[PATCH 0/3] ARM: OMAP1/2+: 32k-timer: Add hwmod lookup for 32k-timer

[PATCH 0/3] ARM: OMAP1/2+: 32k-timer: Add hwmod lookup for 32k-timer

[Vaibhav Hiremath]

This patch series cleans up the existing 32k-sync timer implementation
without any major code change and adds hwmod lookup for omap2+ devices,
if lookup fails then fall back to gp-timer.

With this, we should be able to support multi-omap boot
including devices with/without 32k-sync timer.
For example, AM33xx device doesn't have 32k-sync timer available,
which breaks multi-omap boot.

This patch-series has been boot tested on AM37xEVM platform, it
would be helpful if somebody help me to validate it on OMAP2
platform.

Background:
==========
In 2010 timeframe 'Fillipe Balbi' had submitted first version
of 32k-sync timer cleanup patches, but it did not made its way
to the mainline.

http://www.mail-archive.com/linux-omap@vger.kernel.org/msg37403.html

Yesterday I had submitted the RFC version patch-series, which was
built on top of earlier cleanup patches from 'Fillipe Balbi'.

http://www.spinics.net/lists/linux-omap/msg63004.html

Based on comments (Thanks to Russell, Marc and Tony) from community
it was clear that, arch_init is not the correct way here.


Vaibhav Hiremath (3):
  ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k
    timer
  ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common
    header
  ARM: OMAP2+: hwmod data: Add 32k-sync timer data to hwmod database

 arch/arm/mach-omap2/omap_hwmod_2420_data.c |   53 ++++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_2430_data.c |   52 +++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_3xxx_data.c |   51 +++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_44xx_data.c |    2 +-
 arch/arm/mach-omap2/prcm-common.h          |    4 +
 arch/arm/mach-omap2/timer.c                |   27 ++++-----
 arch/arm/plat-omap/counter_32k.c           |   83 ++++++++++++++-------------
 7 files changed, 215 insertions(+), 57 deletions(-)

[PATCH 0/3] ARM: OMAP1/2+: 32k-timer: Add hwmod lookup for 32k-timer

[Vaibhav Hiremath]

This patch series cleans up the existing 32k-sync timer implementation
without any major code change and adds hwmod lookup for omap2+ devices,
if lookup fails then fall back to gp-timer.

With this, we should be able to support multi-omap boot
including devices with/without 32k-sync timer.
For example, AM33xx device doesn't have 32k-sync timer available,
which breaks multi-omap boot.

This patch-series has been boot tested on AM37xEVM platform, it
would be helpful if somebody help me to validate it on OMAP2
platform.

Background:
==========
In 2010 timeframe 'Fillipe Balbi' had submitted first version
of 32k-sync timer cleanup patches, but it did not made its way
to the mainline.

http://www.mail-archive.com/linux-omap at vger.kernel.org/msg37403.html

Yesterday I had submitted the RFC version patch-series, which was
built on top of earlier cleanup patches from 'Fillipe Balbi'.

http://www.spinics.net/lists/linux-omap/msg63004.html

Based on comments (Thanks to Russell, Marc and Tony) from community
it was clear that, arch_init is not the correct way here.


Vaibhav Hiremath (3):
  ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k
    timer
  ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common
    header
  ARM: OMAP2+: hwmod data: Add 32k-sync timer data to hwmod database

 arch/arm/mach-omap2/omap_hwmod_2420_data.c |   53 ++++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_2430_data.c |   52 +++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_3xxx_data.c |   51 +++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_44xx_data.c |    2 +-
 arch/arm/mach-omap2/prcm-common.h          |    4 +
 arch/arm/mach-omap2/timer.c                |   27 ++++-----
 arch/arm/plat-omap/counter_32k.c           |   83 ++++++++++++++-------------
 7 files changed, 215 insertions(+), 57 deletions(-)

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Vaibhav Hiremath]

OMAP device has 32k-sync timer which is currently used as a
clocksource in the kernel (omap2plus_defconfig).
The current implementation uses compile time selection between
gp-timer and 32k-sync timer, which breaks multi-omap build for
the devices like AM33xx, where 32k-sync timer is not available.

So use hwmod database lookup mechanism, through which at run-time
we can identify availability of 32k-sync timer on the device,
else fall back to gp-timer.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tarun Kanti DebBarma <tarun.kanti@ti.com>
---
 arch/arm/mach-omap2/timer.c      |   27 +++++-------
 arch/arm/plat-omap/counter_32k.c |   83 +++++++++++++++++++------------------
 2 files changed, 54 insertions(+), 56 deletions(-)

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 6eeff0e..b978b39 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 }
 
 /* Clocksource code */
-
-#ifdef CONFIG_OMAP_32K_TIMER
-/*
- * When 32k-timer is enabled, don't use GPTimer for clocksource
- * instead, just leave default clocksource which uses the 32k
- * sync counter.  See clocksource setup in plat-omap/counter_32k.c
- */
-
-static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
-{
-	omap_init_clocksource_32k();
-}
-
-#else
-
 static struct omap_dm_timer clksrc;
 
 /*
@@ -281,6 +266,17 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 {
 	int res;
 
+	/*
+	 * First check for availability for 32k-sync timer.
+	 *
+	 * Return non-zero, means the device doesn't have 32k-sync timer and
+	 * execution will fallback to gp-timer.
+	 */
+	res = omap_init_clocksource_32k();
+	if (!res)
+		return;
+
+	/* Fall back to gp-timer code */
 	res = omap_dm_timer_init_one(&clksrc, gptimer_id, fck_source);
 	BUG_ON(res);
 
@@ -295,7 +291,6 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 		pr_err("Could not register clocksource %s\n",
 			clocksource_gpt.name);
 }
-#endif
 
 #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src,			\
 				clksrc_nr, clksrc_src)			\
diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
index 5f0f229..8504bea 100644
--- a/arch/arm/plat-omap/counter_32k.c
+++ b/arch/arm/plat-omap/counter_32k.c
@@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
 
 int __init omap_init_clocksource_32k(void)
 {
-	static char err[] __initdata = KERN_ERR
-			"%s: can't register clocksource!\n";
-
-	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
-		u32 pbase;
-		unsigned long size = SZ_4K;
-		void __iomem *base;
-		struct clk *sync_32k_ick;
-
-		if (cpu_is_omap16xx()) {
-			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
-			size = SZ_1K;
-		} else if (cpu_is_omap2420())
-			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
-		else if (cpu_is_omap2430())
-			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
-		else if (cpu_is_omap34xx())
-			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
-		else if (cpu_is_omap44xx())
-			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
-		else
+	u32 pbase;
+	unsigned long size = SZ_4K;
+	void __iomem *base;
+	struct clk *sync_32k_ick;
+
+	if (cpu_is_omap16xx()) {
+		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
+		size = SZ_1K;
+	} else if (cpu_class_is_omap2()) {
+		struct omap_hwmod *oh;
+		const char *oh_name = "counter_32k";
+
+		oh = omap_hwmod_lookup(oh_name);
+		if (!oh || oh->slaves_cnt == 0) {
+			pr_err("Could not lookup %s hwmod\n", oh_name);
 			return -ENODEV;
+		}
+		pbase = oh->slaves[0]->addr->pa_start + 0x10;
+	} else {
+		return -ENODEV;
+	}
 
-		/* For this to work we must have a static mapping in io.c for this area */
-		base = ioremap(pbase, size);
-		if (!base)
-			return -ENODEV;
+	/*
+	 * For this to work we must have a static mapping in io.c
+	 * for this area
+	 */
+	base = ioremap(pbase, size);
+	if (!base)
+		return -ENODEV;
 
-		sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
-		if (!IS_ERR(sync_32k_ick))
-			clk_enable(sync_32k_ick);
+	sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
+	if (!IS_ERR(sync_32k_ick))
+		clk_enable(sync_32k_ick);
 
-		timer_32k_base = base;
+	timer_32k_base = base;
 
-		/*
-		 * 120000 rough estimate from the calculations in
-		 * __clocksource_updatefreq_scale.
-		 */
-		clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
-				32768, NSEC_PER_SEC, 120000);
+	/*
+	 * 120000 rough estimate from the calculations in
+	 * __clocksource_updatefreq_scale.
+	 */
+	clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
+			32768, NSEC_PER_SEC, 120000);
 
-		if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32,
-					  clocksource_mmio_readl_up))
-			printk(err, "32k_counter");
+	if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32,
+				clocksource_mmio_readl_up))
+		printk(KERN_ERR "%s: can't register clocksource!\n",
+				"32k_counter");
+
+	setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
 
-		setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
-	}
 	return 0;
 }
-- 
1.7.0.4

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Vaibhav Hiremath]

OMAP device has 32k-sync timer which is currently used as a
clocksource in the kernel (omap2plus_defconfig).
The current implementation uses compile time selection between
gp-timer and 32k-sync timer, which breaks multi-omap build for
the devices like AM33xx, where 32k-sync timer is not available.

So use hwmod database lookup mechanism, through which at run-time
we can identify availability of 32k-sync timer on the device,
else fall back to gp-timer.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tarun Kanti DebBarma <tarun.kanti@ti.com>
---
 arch/arm/mach-omap2/timer.c      |   27 +++++-------
 arch/arm/plat-omap/counter_32k.c |   83 +++++++++++++++++++------------------
 2 files changed, 54 insertions(+), 56 deletions(-)

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 6eeff0e..b978b39 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 }
 
 /* Clocksource code */
-
-#ifdef CONFIG_OMAP_32K_TIMER
-/*
- * When 32k-timer is enabled, don't use GPTimer for clocksource
- * instead, just leave default clocksource which uses the 32k
- * sync counter.  See clocksource setup in plat-omap/counter_32k.c
- */
-
-static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
-{
-	omap_init_clocksource_32k();
-}
-
-#else
-
 static struct omap_dm_timer clksrc;
 
 /*
@@ -281,6 +266,17 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 {
 	int res;
 
+	/*
+	 * First check for availability for 32k-sync timer.
+	 *
+	 * Return non-zero, means the device doesn't have 32k-sync timer and
+	 * execution will fallback to gp-timer.
+	 */
+	res = omap_init_clocksource_32k();
+	if (!res)
+		return;
+
+	/* Fall back to gp-timer code */
 	res = omap_dm_timer_init_one(&clksrc, gptimer_id, fck_source);
 	BUG_ON(res);
 
@@ -295,7 +291,6 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 		pr_err("Could not register clocksource %s\n",
 			clocksource_gpt.name);
 }
-#endif
 
 #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src,			\
 				clksrc_nr, clksrc_src)			\
diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
index 5f0f229..8504bea 100644
--- a/arch/arm/plat-omap/counter_32k.c
+++ b/arch/arm/plat-omap/counter_32k.c
@@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
 
 int __init omap_init_clocksource_32k(void)
 {
-	static char err[] __initdata = KERN_ERR
-			"%s: can't register clocksource!\n";
-
-	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
-		u32 pbase;
-		unsigned long size = SZ_4K;
-		void __iomem *base;
-		struct clk *sync_32k_ick;
-
-		if (cpu_is_omap16xx()) {
-			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
-			size = SZ_1K;
-		} else if (cpu_is_omap2420())
-			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
-		else if (cpu_is_omap2430())
-			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
-		else if (cpu_is_omap34xx())
-			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
-		else if (cpu_is_omap44xx())
-			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
-		else
+	u32 pbase;
+	unsigned long size = SZ_4K;
+	void __iomem *base;
+	struct clk *sync_32k_ick;
+
+	if (cpu_is_omap16xx()) {
+		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
+		size = SZ_1K;
+	} else if (cpu_class_is_omap2()) {
+		struct omap_hwmod *oh;
+		const char *oh_name = "counter_32k";
+
+		oh = omap_hwmod_lookup(oh_name);
+		if (!oh || oh->slaves_cnt == 0) {
+			pr_err("Could not lookup %s hwmod\n", oh_name);
 			return -ENODEV;
+		}
+		pbase = oh->slaves[0]->addr->pa_start + 0x10;
+	} else {
+		return -ENODEV;
+	}
 
-		/* For this to work we must have a static mapping in io.c for this area */
-		base = ioremap(pbase, size);
-		if (!base)
-			return -ENODEV;
+	/*
+	 * For this to work we must have a static mapping in io.c
+	 * for this area
+	 */
+	base = ioremap(pbase, size);
+	if (!base)
+		return -ENODEV;
 
-		sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
-		if (!IS_ERR(sync_32k_ick))
-			clk_enable(sync_32k_ick);
+	sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
+	if (!IS_ERR(sync_32k_ick))
+		clk_enable(sync_32k_ick);
 
-		timer_32k_base = base;
+	timer_32k_base = base;
 
-		/*
-		 * 120000 rough estimate from the calculations in
-		 * __clocksource_updatefreq_scale.
-		 */
-		clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
-				32768, NSEC_PER_SEC, 120000);
+	/*
+	 * 120000 rough estimate from the calculations in
+	 * __clocksource_updatefreq_scale.
+	 */
+	clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
+			32768, NSEC_PER_SEC, 120000);
 
-		if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32,
-					  clocksource_mmio_readl_up))
-			printk(err, "32k_counter");
+	if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32,
+				clocksource_mmio_readl_up))
+		printk(KERN_ERR "%s: can't register clocksource!\n",
+				"32k_counter");
+
+	setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
 
-		setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
-	}
 	return 0;
 }
-- 
1.7.0.4

[PATCH 2/3] ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common header

[Vaibhav Hiremath]

Add missing idle_st bit for 32k-sync timer into the prcm-common
header file, required for hwmod data.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Walmsley <paul@pwsan.com>
---
 arch/arm/mach-omap2/prcm-common.h |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/prcm-common.h b/arch/arm/mach-omap2/prcm-common.h
index 5aa5435..29955d5 100644
--- a/arch/arm/mach-omap2/prcm-common.h
+++ b/arch/arm/mach-omap2/prcm-common.h
@@ -177,6 +177,8 @@
 /* PM_WKST_WKUP, CM_IDLEST_WKUP shared bits */
 #define OMAP24XX_ST_GPIOS_SHIFT				2
 #define OMAP24XX_ST_GPIOS_MASK				(1 << 2)
+#define OMAP24XX_ST_32KSYNC_SHIFT			1
+#define OMAP24XX_ST_32KSYNC_MASK			(1 << 1)
 #define OMAP24XX_ST_GPT1_SHIFT				0
 #define OMAP24XX_ST_GPT1_MASK				(1 << 0)
 
@@ -307,6 +309,8 @@
 #define OMAP3430_ST_SR1_MASK				(1 << 6)
 #define OMAP3430_ST_GPIO1_SHIFT				3
 #define OMAP3430_ST_GPIO1_MASK				(1 << 3)
+#define OMAP3430_ST_32KSYNC_SHIFT			2
+#define OMAP3430_ST_32KSYNC_MASK			(1 << 2)
 #define OMAP3430_ST_GPT12_SHIFT				1
 #define OMAP3430_ST_GPT12_MASK				(1 << 1)
 #define OMAP3430_ST_GPT1_SHIFT				0
-- 
1.7.0.4

[PATCH 2/3] ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common header

[Vaibhav Hiremath]

Add missing idle_st bit for 32k-sync timer into the prcm-common
header file, required for hwmod data.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Walmsley <paul@pwsan.com>
---
 arch/arm/mach-omap2/prcm-common.h |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/prcm-common.h b/arch/arm/mach-omap2/prcm-common.h
index 5aa5435..29955d5 100644
--- a/arch/arm/mach-omap2/prcm-common.h
+++ b/arch/arm/mach-omap2/prcm-common.h
@@ -177,6 +177,8 @@
 /* PM_WKST_WKUP, CM_IDLEST_WKUP shared bits */
 #define OMAP24XX_ST_GPIOS_SHIFT				2
 #define OMAP24XX_ST_GPIOS_MASK				(1 << 2)
+#define OMAP24XX_ST_32KSYNC_SHIFT			1
+#define OMAP24XX_ST_32KSYNC_MASK			(1 << 1)
 #define OMAP24XX_ST_GPT1_SHIFT				0
 #define OMAP24XX_ST_GPT1_MASK				(1 << 0)
 
@@ -307,6 +309,8 @@
 #define OMAP3430_ST_SR1_MASK				(1 << 6)
 #define OMAP3430_ST_GPIO1_SHIFT				3
 #define OMAP3430_ST_GPIO1_MASK				(1 << 3)
+#define OMAP3430_ST_32KSYNC_SHIFT			2
+#define OMAP3430_ST_32KSYNC_MASK			(1 << 2)
 #define OMAP3430_ST_GPT12_SHIFT				1
 #define OMAP3430_ST_GPT12_MASK				(1 << 1)
 #define OMAP3430_ST_GPT1_SHIFT				0
-- 
1.7.0.4

[PATCH 3/3] ARM: OMAP2+: hwmod data: Add 32k-sync timer data to hwmod database

[Vaibhav Hiremath]

Add 32k-sync timer hwmod data to omap2 & 3 hwmod table
and also enable existing hwmod data for omap4 (was disabled before).

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Walmsley <paul@pwsan.com>
---
 arch/arm/mach-omap2/omap_hwmod_2420_data.c |   53 ++++++++++++++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_2430_data.c |   52 +++++++++++++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_3xxx_data.c |   51 ++++++++++++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_44xx_data.c |    2 +-
 4 files changed, 157 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod_2420_data.c b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
index a5409ce..2091a5c 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2420_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
@@ -54,6 +54,7 @@ static struct omap_hwmod omap2420_gpio4_hwmod;
 static struct omap_hwmod omap2420_dma_system_hwmod;
 static struct omap_hwmod omap2420_mcspi1_hwmod;
 static struct omap_hwmod omap2420_mcspi2_hwmod;
+static struct omap_hwmod omap2420_counter_32k_hwmod;
 
 /* L3 -> L4_CORE interface */
 static struct omap_hwmod_ocp_if omap2420_l3_main__l4_core = {
@@ -1513,6 +1514,55 @@ static struct omap_hwmod omap2420_mcbsp2_hwmod = {
 	.slaves_cnt	= ARRAY_SIZE(omap2420_mcbsp2_slaves),
 };
 
+/*
+ * '32K sync counter' class
+ * 32-bit ordinary counter, clocked by the falling edge of the 32 khz clock
+ */
+static struct omap_hwmod_class omap2420_counter_hwmod_class = {
+	.name = "counter",
+};
+
+/* counter_32k */
+static struct omap_hwmod_addr_space omap2420_counter_32k_addrs[] = {
+	{
+		.pa_start	= 0x48004000,
+		.pa_end		= 0x48004000 + SZ_4K,
+		.flags		= ADDR_TYPE_RT
+	},
+	{ }
+};
+
+/* l4_wkup -> counter_32k */
+static struct omap_hwmod_ocp_if omap2420_l4_wkup__counter_32k = {
+	.master		= &omap2420_l4_wkup_hwmod,
+	.slave		= &omap2420_counter_32k_hwmod,
+	.clk		= "l4_ck",
+	.addr		= omap2420_counter_32k_addrs,
+	.user		= OCP_USER_MPU | OCP_USER_SDMA,
+};
+
+/* counter_32k slave ports */
+static struct omap_hwmod_ocp_if *omap2420_counter_32k_slaves[] = {
+	&omap2420_l4_wkup__counter_32k,
+};
+
+static struct omap_hwmod omap2420_counter_32k_hwmod = {
+	.name		= "counter_32k",
+	.class		= &omap2420_counter_hwmod_class,
+	.main_clk	= "sync_32k_ick",
+	.prcm = {
+		.omap2	= {
+			.module_offs		= WKUP_MOD,
+			.prcm_reg_id		= 1,
+			.module_bit		= OMAP24XX_ST_32KSYNC_SHIFT,
+			.idlest_reg_id		= 1,
+			.idlest_idle_bit	= OMAP24XX_ST_32KSYNC_SHIFT,
+		},
+	},
+	.slaves		= omap2420_counter_32k_slaves,
+	.slaves_cnt	= ARRAY_SIZE(omap2420_counter_32k_slaves),
+};
+
 static __initdata struct omap_hwmod *omap2420_hwmods[] = {
 	&omap2420_l3_main_hwmod,
 	&omap2420_l4_core_hwmod,
@@ -1565,6 +1615,9 @@ static __initdata struct omap_hwmod *omap2420_hwmods[] = {
 	/* mcspi class */
 	&omap2420_mcspi1_hwmod,
 	&omap2420_mcspi2_hwmod,
+
+	/* 32k sync timer */
+	&omap2420_counter_32k_hwmod,
 	NULL,
 };
 
diff --git a/arch/arm/mach-omap2/omap_hwmod_2430_data.c b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
index c4f56cb..f7cc4bb 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2430_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
@@ -64,6 +64,7 @@ static struct omap_hwmod omap2430_mcspi2_hwmod;
 static struct omap_hwmod omap2430_mcspi3_hwmod;
 static struct omap_hwmod omap2430_mmc1_hwmod;
 static struct omap_hwmod omap2430_mmc2_hwmod;
+static struct omap_hwmod omap2430_counter_32k_hwmod;
 
 /* L3 -> L4_CORE interface */
 static struct omap_hwmod_ocp_if omap2430_l3_main__l4_core = {
@@ -2001,6 +2002,55 @@ static struct omap_hwmod omap2430_mmc2_hwmod = {
 	.class		= &omap2430_mmc_class,
 };
 
+/*
+ * '32K sync counter' class
+ * 32-bit ordinary counter, clocked by the falling edge of the 32 khz clock
+ */
+static struct omap_hwmod_class omap2430_counter_hwmod_class = {
+	.name = "counter",
+};
+
+/* counter_32k */
+static struct omap_hwmod_addr_space omap2430_counter_32k_addrs[] = {
+	{
+		.pa_start	= 0x49020000,
+		.pa_end		= 0x49020000 + SZ_4K,
+		.flags		= ADDR_TYPE_RT
+	},
+	{ }
+};
+
+/* l4_wkup -> counter_32k */
+static struct omap_hwmod_ocp_if omap2430_l4_wkup__counter_32k = {
+	.master		= &omap2430_l4_wkup_hwmod,
+	.slave		= &omap2430_counter_32k_hwmod,
+	.clk		= "l4_ck",
+	.addr		= omap2430_counter_32k_addrs,
+	.user		= OCP_USER_MPU | OCP_USER_SDMA,
+};
+
+/* counter_32k slave ports */
+static struct omap_hwmod_ocp_if *omap2430_counter_32k_slaves[] = {
+	&omap2430_l4_wkup__counter_32k,
+};
+
+static struct omap_hwmod omap2430_counter_32k_hwmod = {
+	.name		= "counter_32k",
+	.class		= &omap2430_counter_hwmod_class,
+	.main_clk	= "sync_32k_ick",
+	.prcm		= {
+		.omap2	= {
+			.module_offs		= WKUP_MOD,
+			.prcm_reg_id		= 1,
+			.module_bit		= OMAP24XX_ST_32KSYNC_SHIFT,
+			.idlest_reg_id		= 1,
+			.idlest_idle_bit	= OMAP24XX_ST_32KSYNC_SHIFT,
+		},
+	},
+	.slaves		= omap2430_counter_32k_slaves,
+	.slaves_cnt	= ARRAY_SIZE(omap2430_counter_32k_slaves),
+};
+
 static __initdata struct omap_hwmod *omap2430_hwmods[] = {
 	&omap2430_l3_main_hwmod,
 	&omap2430_l4_core_hwmod,
@@ -2064,6 +2114,8 @@ static __initdata struct omap_hwmod *omap2430_hwmods[] = {
 	/* usbotg class*/
 	&omap2430_usbhsotg_hwmod,
 
+	/* 32k sync timer */
+	&omap2430_counter_32k_hwmod,
 	NULL,
 };
 
diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
index 5324e8d..19a3591 100644
--- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
@@ -86,6 +86,7 @@ static struct omap_hwmod omap3xxx_mcbsp2_sidetone_hwmod;
 static struct omap_hwmod omap3xxx_mcbsp3_sidetone_hwmod;
 static struct omap_hwmod omap3xxx_usb_host_hs_hwmod;
 static struct omap_hwmod omap3xxx_usb_tll_hs_hwmod;
+static struct omap_hwmod omap3xxx_counter_32k_hwmod;
 
 /* L3 -> L4_CORE interface */
 static struct omap_hwmod_ocp_if omap3xxx_l3_main__l4_core = {
@@ -3498,6 +3499,55 @@ static struct omap_hwmod omap3xxx_usb_tll_hs_hwmod = {
 	.slaves_cnt	= ARRAY_SIZE(omap3xxx_usb_tll_hs_slaves),
 };
 
+/*
+ * '32K sync counter' class
+ * 32-bit ordinary counter, clocked by the falling edge of the 32 khz clock
+ */
+static struct omap_hwmod_class omap3xxx_counter_hwmod_class = {
+	.name = "counter",
+};
+
+/* counter_32k */
+static struct omap_hwmod_addr_space omap3xxx_counter_32k_addrs[] = {
+	{
+		.pa_start	= 0x48320000,
+		.pa_end		= 0x48320000 + SZ_4K,
+		.flags		= ADDR_TYPE_RT
+	},
+	{ }
+};
+
+/* l4_wkup -> counter_32k */
+static struct omap_hwmod_ocp_if omap3xxx_l4_wkup__counter_32k = {
+	.master		= &omap3xxx_l4_wkup_hwmod,
+	.slave		= &omap3xxx_counter_32k_hwmod,
+	.clk		= "wkup_l4_ick",
+	.addr		= omap3xxx_counter_32k_addrs,
+	.user		= OCP_USER_MPU | OCP_USER_SDMA,
+};
+
+/* counter_32k slave ports */
+static struct omap_hwmod_ocp_if *omap3xxx_counter_32k_slaves[] = {
+	&omap3xxx_l4_wkup__counter_32k,
+};
+
+static struct omap_hwmod omap3xxx_counter_32k_hwmod = {
+	.name		= "counter_32k",
+	.class		= &omap3xxx_counter_hwmod_class,
+	.main_clk	= "omap_32ksync_ick",
+	.prcm		= {
+		.omap2	= {
+			.module_offs		= WKUP_MOD,
+			.prcm_reg_id		= 1,
+			.module_bit		= OMAP3430_ST_32KSYNC_SHIFT,
+			.idlest_reg_id		= 1,
+			.idlest_idle_bit	= OMAP3430_ST_32KSYNC_SHIFT,
+		},
+	},
+	.slaves		= omap3xxx_counter_32k_slaves,
+	.slaves_cnt	= ARRAY_SIZE(omap3xxx_counter_32k_slaves),
+};
+
 static __initdata struct omap_hwmod *omap3xxx_hwmods[] = {
 	&omap3xxx_l3_main_hwmod,
 	&omap3xxx_l4_core_hwmod,
@@ -3561,6 +3611,7 @@ static __initdata struct omap_hwmod *omap3xxx_hwmods[] = {
 	&omap34xx_mcspi3,
 	&omap34xx_mcspi4,
 
+	&omap3xxx_counter_32k_hwmod,
 	NULL,
 };
 
diff --git a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
index f9f1510..cd60b13 100644
--- a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
@@ -5510,7 +5510,7 @@ static __initdata struct omap_hwmod *omap44xx_hwmods[] = {
 	&omap44xx_bandgap_hwmod,
 
 	/* counter class */
-/*	&omap44xx_counter_32k_hwmod, */
+	&omap44xx_counter_32k_hwmod,
 
 	/* dma class */
 	&omap44xx_dma_system_hwmod,
-- 
1.7.0.4

[PATCH 3/3] ARM: OMAP2+: hwmod data: Add 32k-sync timer data to hwmod database

[Vaibhav Hiremath]

Add 32k-sync timer hwmod data to omap2 & 3 hwmod table
and also enable existing hwmod data for omap4 (was disabled before).

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Walmsley <paul@pwsan.com>
---
 arch/arm/mach-omap2/omap_hwmod_2420_data.c |   53 ++++++++++++++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_2430_data.c |   52 +++++++++++++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_3xxx_data.c |   51 ++++++++++++++++++++++++++
 arch/arm/mach-omap2/omap_hwmod_44xx_data.c |    2 +-
 4 files changed, 157 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod_2420_data.c b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
index a5409ce..2091a5c 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2420_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
@@ -54,6 +54,7 @@ static struct omap_hwmod omap2420_gpio4_hwmod;
 static struct omap_hwmod omap2420_dma_system_hwmod;
 static struct omap_hwmod omap2420_mcspi1_hwmod;
 static struct omap_hwmod omap2420_mcspi2_hwmod;
+static struct omap_hwmod omap2420_counter_32k_hwmod;
 
 /* L3 -> L4_CORE interface */
 static struct omap_hwmod_ocp_if omap2420_l3_main__l4_core = {
@@ -1513,6 +1514,55 @@ static struct omap_hwmod omap2420_mcbsp2_hwmod = {
 	.slaves_cnt	= ARRAY_SIZE(omap2420_mcbsp2_slaves),
 };
 
+/*
+ * '32K sync counter' class
+ * 32-bit ordinary counter, clocked by the falling edge of the 32 khz clock
+ */
+static struct omap_hwmod_class omap2420_counter_hwmod_class = {
+	.name = "counter",
+};
+
+/* counter_32k */
+static struct omap_hwmod_addr_space omap2420_counter_32k_addrs[] = {
+	{
+		.pa_start	= 0x48004000,
+		.pa_end		= 0x48004000 + SZ_4K,
+		.flags		= ADDR_TYPE_RT
+	},
+	{ }
+};
+
+/* l4_wkup -> counter_32k */
+static struct omap_hwmod_ocp_if omap2420_l4_wkup__counter_32k = {
+	.master		= &omap2420_l4_wkup_hwmod,
+	.slave		= &omap2420_counter_32k_hwmod,
+	.clk		= "l4_ck",
+	.addr		= omap2420_counter_32k_addrs,
+	.user		= OCP_USER_MPU | OCP_USER_SDMA,
+};
+
+/* counter_32k slave ports */
+static struct omap_hwmod_ocp_if *omap2420_counter_32k_slaves[] = {
+	&omap2420_l4_wkup__counter_32k,
+};
+
+static struct omap_hwmod omap2420_counter_32k_hwmod = {
+	.name		= "counter_32k",
+	.class		= &omap2420_counter_hwmod_class,
+	.main_clk	= "sync_32k_ick",
+	.prcm = {
+		.omap2	= {
+			.module_offs		= WKUP_MOD,
+			.prcm_reg_id		= 1,
+			.module_bit		= OMAP24XX_ST_32KSYNC_SHIFT,
+			.idlest_reg_id		= 1,
+			.idlest_idle_bit	= OMAP24XX_ST_32KSYNC_SHIFT,
+		},
+	},
+	.slaves		= omap2420_counter_32k_slaves,
+	.slaves_cnt	= ARRAY_SIZE(omap2420_counter_32k_slaves),
+};
+
 static __initdata struct omap_hwmod *omap2420_hwmods[] = {
 	&omap2420_l3_main_hwmod,
 	&omap2420_l4_core_hwmod,
@@ -1565,6 +1615,9 @@ static __initdata struct omap_hwmod *omap2420_hwmods[] = {
 	/* mcspi class */
 	&omap2420_mcspi1_hwmod,
 	&omap2420_mcspi2_hwmod,
+
+	/* 32k sync timer */
+	&omap2420_counter_32k_hwmod,
 	NULL,
 };
 
diff --git a/arch/arm/mach-omap2/omap_hwmod_2430_data.c b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
index c4f56cb..f7cc4bb 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2430_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
@@ -64,6 +64,7 @@ static struct omap_hwmod omap2430_mcspi2_hwmod;
 static struct omap_hwmod omap2430_mcspi3_hwmod;
 static struct omap_hwmod omap2430_mmc1_hwmod;
 static struct omap_hwmod omap2430_mmc2_hwmod;
+static struct omap_hwmod omap2430_counter_32k_hwmod;
 
 /* L3 -> L4_CORE interface */
 static struct omap_hwmod_ocp_if omap2430_l3_main__l4_core = {
@@ -2001,6 +2002,55 @@ static struct omap_hwmod omap2430_mmc2_hwmod = {
 	.class		= &omap2430_mmc_class,
 };
 
+/*
+ * '32K sync counter' class
+ * 32-bit ordinary counter, clocked by the falling edge of the 32 khz clock
+ */
+static struct omap_hwmod_class omap2430_counter_hwmod_class = {
+	.name = "counter",
+};
+
+/* counter_32k */
+static struct omap_hwmod_addr_space omap2430_counter_32k_addrs[] = {
+	{
+		.pa_start	= 0x49020000,
+		.pa_end		= 0x49020000 + SZ_4K,
+		.flags		= ADDR_TYPE_RT
+	},
+	{ }
+};
+
+/* l4_wkup -> counter_32k */
+static struct omap_hwmod_ocp_if omap2430_l4_wkup__counter_32k = {
+	.master		= &omap2430_l4_wkup_hwmod,
+	.slave		= &omap2430_counter_32k_hwmod,
+	.clk		= "l4_ck",
+	.addr		= omap2430_counter_32k_addrs,
+	.user		= OCP_USER_MPU | OCP_USER_SDMA,
+};
+
+/* counter_32k slave ports */
+static struct omap_hwmod_ocp_if *omap2430_counter_32k_slaves[] = {
+	&omap2430_l4_wkup__counter_32k,
+};
+
+static struct omap_hwmod omap2430_counter_32k_hwmod = {
+	.name		= "counter_32k",
+	.class		= &omap2430_counter_hwmod_class,
+	.main_clk	= "sync_32k_ick",
+	.prcm		= {
+		.omap2	= {
+			.module_offs		= WKUP_MOD,
+			.prcm_reg_id		= 1,
+			.module_bit		= OMAP24XX_ST_32KSYNC_SHIFT,
+			.idlest_reg_id		= 1,
+			.idlest_idle_bit	= OMAP24XX_ST_32KSYNC_SHIFT,
+		},
+	},
+	.slaves		= omap2430_counter_32k_slaves,
+	.slaves_cnt	= ARRAY_SIZE(omap2430_counter_32k_slaves),
+};
+
 static __initdata struct omap_hwmod *omap2430_hwmods[] = {
 	&omap2430_l3_main_hwmod,
 	&omap2430_l4_core_hwmod,
@@ -2064,6 +2114,8 @@ static __initdata struct omap_hwmod *omap2430_hwmods[] = {
 	/* usbotg class*/
 	&omap2430_usbhsotg_hwmod,
 
+	/* 32k sync timer */
+	&omap2430_counter_32k_hwmod,
 	NULL,
 };
 
diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
index 5324e8d..19a3591 100644
--- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
@@ -86,6 +86,7 @@ static struct omap_hwmod omap3xxx_mcbsp2_sidetone_hwmod;
 static struct omap_hwmod omap3xxx_mcbsp3_sidetone_hwmod;
 static struct omap_hwmod omap3xxx_usb_host_hs_hwmod;
 static struct omap_hwmod omap3xxx_usb_tll_hs_hwmod;
+static struct omap_hwmod omap3xxx_counter_32k_hwmod;
 
 /* L3 -> L4_CORE interface */
 static struct omap_hwmod_ocp_if omap3xxx_l3_main__l4_core = {
@@ -3498,6 +3499,55 @@ static struct omap_hwmod omap3xxx_usb_tll_hs_hwmod = {
 	.slaves_cnt	= ARRAY_SIZE(omap3xxx_usb_tll_hs_slaves),
 };
 
+/*
+ * '32K sync counter' class
+ * 32-bit ordinary counter, clocked by the falling edge of the 32 khz clock
+ */
+static struct omap_hwmod_class omap3xxx_counter_hwmod_class = {
+	.name = "counter",
+};
+
+/* counter_32k */
+static struct omap_hwmod_addr_space omap3xxx_counter_32k_addrs[] = {
+	{
+		.pa_start	= 0x48320000,
+		.pa_end		= 0x48320000 + SZ_4K,
+		.flags		= ADDR_TYPE_RT
+	},
+	{ }
+};
+
+/* l4_wkup -> counter_32k */
+static struct omap_hwmod_ocp_if omap3xxx_l4_wkup__counter_32k = {
+	.master		= &omap3xxx_l4_wkup_hwmod,
+	.slave		= &omap3xxx_counter_32k_hwmod,
+	.clk		= "wkup_l4_ick",
+	.addr		= omap3xxx_counter_32k_addrs,
+	.user		= OCP_USER_MPU | OCP_USER_SDMA,
+};
+
+/* counter_32k slave ports */
+static struct omap_hwmod_ocp_if *omap3xxx_counter_32k_slaves[] = {
+	&omap3xxx_l4_wkup__counter_32k,
+};
+
+static struct omap_hwmod omap3xxx_counter_32k_hwmod = {
+	.name		= "counter_32k",
+	.class		= &omap3xxx_counter_hwmod_class,
+	.main_clk	= "omap_32ksync_ick",
+	.prcm		= {
+		.omap2	= {
+			.module_offs		= WKUP_MOD,
+			.prcm_reg_id		= 1,
+			.module_bit		= OMAP3430_ST_32KSYNC_SHIFT,
+			.idlest_reg_id		= 1,
+			.idlest_idle_bit	= OMAP3430_ST_32KSYNC_SHIFT,
+		},
+	},
+	.slaves		= omap3xxx_counter_32k_slaves,
+	.slaves_cnt	= ARRAY_SIZE(omap3xxx_counter_32k_slaves),
+};
+
 static __initdata struct omap_hwmod *omap3xxx_hwmods[] = {
 	&omap3xxx_l3_main_hwmod,
 	&omap3xxx_l4_core_hwmod,
@@ -3561,6 +3611,7 @@ static __initdata struct omap_hwmod *omap3xxx_hwmods[] = {
 	&omap34xx_mcspi3,
 	&omap34xx_mcspi4,
 
+	&omap3xxx_counter_32k_hwmod,
 	NULL,
 };
 
diff --git a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
index f9f1510..cd60b13 100644
--- a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
@@ -5510,7 +5510,7 @@ static __initdata struct omap_hwmod *omap44xx_hwmods[] = {
 	&omap44xx_bandgap_hwmod,
 
 	/* counter class */
-/*	&omap44xx_counter_32k_hwmod, */
+	&omap44xx_counter_32k_hwmod,
 
 	/* dma class */
 	&omap44xx_dma_system_hwmod,
-- 
1.7.0.4

RE: [PATCH 0/3] ARM: OMAP1/2+: 32k-timer: Add hwmod lookup for 32k-timer

[Hiremath, Vaibhav]

On Thu, Jan 19, 2012 at 19:58:21, Hiremath, Vaibhav wrote:
> This patch series cleans up the existing 32k-sync timer implementation
> without any major code change and adds hwmod lookup for omap2+ devices,
> if lookup fails then fall back to gp-timer.
> 
> With this, we should be able to support multi-omap boot
> including devices with/without 32k-sync timer.
> For example, AM33xx device doesn't have 32k-sync timer available,
> which breaks multi-omap boot.
> 
> This patch-series has been boot tested on AM37xEVM platform, it
> would be helpful if somebody help me to validate it on OMAP2
> platform.
> 
> Background:
> ==========
> In 2010 timeframe 'Fillipe Balbi' had submitted first version
> of 32k-sync timer cleanup patches, but it did not made its way
> to the mainline.
> 
> http://www.mail-archive.com/linux-omap@vger.kernel.org/msg37403.html
> 
> Yesterday I had submitted the RFC version patch-series, which was
> built on top of earlier cleanup patches from 'Fillipe Balbi'.
> 
> http://www.spinics.net/lists/linux-omap/msg63004.html
> 
> Based on comments (Thanks to Russell, Marc and Tony) from community
> it was clear that, arch_init is not the correct way here.
> 
> 
> Vaibhav Hiremath (3):
>   ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k
>     timer
>   ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common
>     header
>   ARM: OMAP2+: hwmod data: Add 32k-sync timer data to hwmod database
> 

Tony,

If there are no review comments, can this be merged?

Thanks,
Vaibhav

>  arch/arm/mach-omap2/omap_hwmod_2420_data.c |   53 ++++++++++++++++++
>  arch/arm/mach-omap2/omap_hwmod_2430_data.c |   52 +++++++++++++++++
>  arch/arm/mach-omap2/omap_hwmod_3xxx_data.c |   51 +++++++++++++++++
>  arch/arm/mach-omap2/omap_hwmod_44xx_data.c |    2 +-
>  arch/arm/mach-omap2/prcm-common.h          |    4 +
>  arch/arm/mach-omap2/timer.c                |   27 ++++-----
>  arch/arm/plat-omap/counter_32k.c           |   83 ++++++++++++++-------------
>  7 files changed, 215 insertions(+), 57 deletions(-)
> 
> 

[PATCH 0/3] ARM: OMAP1/2+: 32k-timer: Add hwmod lookup for 32k-timer

[Hiremath, Vaibhav]

On Thu, Jan 19, 2012 at 19:58:21, Hiremath, Vaibhav wrote:
> This patch series cleans up the existing 32k-sync timer implementation
> without any major code change and adds hwmod lookup for omap2+ devices,
> if lookup fails then fall back to gp-timer.
> 
> With this, we should be able to support multi-omap boot
> including devices with/without 32k-sync timer.
> For example, AM33xx device doesn't have 32k-sync timer available,
> which breaks multi-omap boot.
> 
> This patch-series has been boot tested on AM37xEVM platform, it
> would be helpful if somebody help me to validate it on OMAP2
> platform.
> 
> Background:
> ==========
> In 2010 timeframe 'Fillipe Balbi' had submitted first version
> of 32k-sync timer cleanup patches, but it did not made its way
> to the mainline.
> 
> http://www.mail-archive.com/linux-omap at vger.kernel.org/msg37403.html
> 
> Yesterday I had submitted the RFC version patch-series, which was
> built on top of earlier cleanup patches from 'Fillipe Balbi'.
> 
> http://www.spinics.net/lists/linux-omap/msg63004.html
> 
> Based on comments (Thanks to Russell, Marc and Tony) from community
> it was clear that, arch_init is not the correct way here.
> 
> 
> Vaibhav Hiremath (3):
>   ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k
>     timer
>   ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common
>     header
>   ARM: OMAP2+: hwmod data: Add 32k-sync timer data to hwmod database
> 

Tony,

If there are no review comments, can this be merged?

Thanks,
Vaibhav

>  arch/arm/mach-omap2/omap_hwmod_2420_data.c |   53 ++++++++++++++++++
>  arch/arm/mach-omap2/omap_hwmod_2430_data.c |   52 +++++++++++++++++
>  arch/arm/mach-omap2/omap_hwmod_3xxx_data.c |   51 +++++++++++++++++
>  arch/arm/mach-omap2/omap_hwmod_44xx_data.c |    2 +-
>  arch/arm/mach-omap2/prcm-common.h          |    4 +
>  arch/arm/mach-omap2/timer.c                |   27 ++++-----
>  arch/arm/plat-omap/counter_32k.c           |   83 ++++++++++++++-------------
>  7 files changed, 215 insertions(+), 57 deletions(-)
> 
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

Vaibhav Hiremath <hvaibhav@ti.com> writes:

> OMAP device has 32k-sync timer which is currently used as a
> clocksource in the kernel (omap2plus_defconfig).
> The current implementation uses compile time selection between
> gp-timer and 32k-sync timer, which breaks multi-omap build for
> the devices like AM33xx, where 32k-sync timer is not available.
>
> So use hwmod database lookup mechanism, through which at run-time
> we can identify availability of 32k-sync timer on the device,
> else fall back to gp-timer.

With the runtime detection & fallback, I suggest also removing the
Kconfig choice between the two as well.

Kevin

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

Vaibhav Hiremath <hvaibhav@ti.com> writes:

> OMAP device has 32k-sync timer which is currently used as a
> clocksource in the kernel (omap2plus_defconfig).
> The current implementation uses compile time selection between
> gp-timer and 32k-sync timer, which breaks multi-omap build for
> the devices like AM33xx, where 32k-sync timer is not available.
>
> So use hwmod database lookup mechanism, through which at run-time
> we can identify availability of 32k-sync timer on the device,
> else fall back to gp-timer.

With the runtime detection & fallback, I suggest also removing the
Kconfig choice between the two as well.

Kevin

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Jan 24, 2012 at 05:08:50, Hilman, Kevin wrote:
> Vaibhav Hiremath <hvaibhav@ti.com> writes:
> 
> > OMAP device has 32k-sync timer which is currently used as a
> > clocksource in the kernel (omap2plus_defconfig).
> > The current implementation uses compile time selection between
> > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > the devices like AM33xx, where 32k-sync timer is not available.
> >
> > So use hwmod database lookup mechanism, through which at run-time
> > we can identify availability of 32k-sync timer on the device,
> > else fall back to gp-timer.
> 
> With the runtime detection & fallback, I suggest also removing the
> Kconfig choice between the two as well.
> 
Kevin,

Actually I thought of cleaning whole 32KTIMER related code,
but then realized that, it would be major cleanup, since
it is being used in lot of places.

So let's not block this patch-series for this further cleanup.
I will work on cleaning up the complete 32KTIMER macro and 
submit the patches.


Simple grep command gives -
===========================
psplinux060:/datalocal/omap-kernel>grep -r OMAP_32K_TIMER *
arch/arm/mach-omap1/Makefile:obj-$(CONFIG_OMAP_32K_TIMER)       += timer32k.o
arch/arm/mach-omap1/time.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/mach-omap1/pm.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/mach-omap1/pm.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/mach-omap1/pm.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/mach-omap1/timer32k.c:#define OMAP_32K_TIMER_TICK_PERIOD       ((OMAP_32K_TICKS_PER_SEC / HZ) - 1)
arch/arm/mach-omap1/timer32k.c:         omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD);
arch/arm/mach-omap2/timer.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/configs/omap1_defconfig:CONFIG_OMAP_32K_TIMER=y
arch/arm/plat-omap/include/plat/timex.h:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/plat-omap/include/plat/timex.h:#define CLOCK_TICK_RATE         (CONFIG_OMAP_32K_TIMER_HZ)
arch/arm/plat-omap/include/plat/param.h:#ifdef CONFIG_OMAP_32K_TIMER_HZ
arch/arm/plat-omap/include/plat/param.h:#define HZ      CONFIG_OMAP_32K_TIMER_HZ
arch/arm/plat-omap/Kconfig:config OMAP_32K_TIMER
arch/arm/plat-omap/Kconfig:config OMAP_32K_TIMER_HZ
arch/arm/plat-omap/Kconfig:     depends on OMAP_32K_TIMER
arch/arm/Kconfig:       default OMAP_32K_TIMER_HZ if ARCH_OMAP && OMAP_32K_TIMER



Thanks,
Vaibhav

> Kevin
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Jan 24, 2012 at 05:08:50, Hilman, Kevin wrote:
> Vaibhav Hiremath <hvaibhav@ti.com> writes:
> 
> > OMAP device has 32k-sync timer which is currently used as a
> > clocksource in the kernel (omap2plus_defconfig).
> > The current implementation uses compile time selection between
> > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > the devices like AM33xx, where 32k-sync timer is not available.
> >
> > So use hwmod database lookup mechanism, through which at run-time
> > we can identify availability of 32k-sync timer on the device,
> > else fall back to gp-timer.
> 
> With the runtime detection & fallback, I suggest also removing the
> Kconfig choice between the two as well.
> 
Kevin,

Actually I thought of cleaning whole 32KTIMER related code,
but then realized that, it would be major cleanup, since
it is being used in lot of places.

So let's not block this patch-series for this further cleanup.
I will work on cleaning up the complete 32KTIMER macro and 
submit the patches.


Simple grep command gives -
===========================
psplinux060:/datalocal/omap-kernel>grep -r OMAP_32K_TIMER *
arch/arm/mach-omap1/Makefile:obj-$(CONFIG_OMAP_32K_TIMER)       += timer32k.o
arch/arm/mach-omap1/time.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/mach-omap1/pm.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/mach-omap1/pm.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/mach-omap1/pm.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/mach-omap1/timer32k.c:#define OMAP_32K_TIMER_TICK_PERIOD       ((OMAP_32K_TICKS_PER_SEC / HZ) - 1)
arch/arm/mach-omap1/timer32k.c:         omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD);
arch/arm/mach-omap2/timer.c:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/configs/omap1_defconfig:CONFIG_OMAP_32K_TIMER=y
arch/arm/plat-omap/include/plat/timex.h:#ifdef CONFIG_OMAP_32K_TIMER
arch/arm/plat-omap/include/plat/timex.h:#define CLOCK_TICK_RATE         (CONFIG_OMAP_32K_TIMER_HZ)
arch/arm/plat-omap/include/plat/param.h:#ifdef CONFIG_OMAP_32K_TIMER_HZ
arch/arm/plat-omap/include/plat/param.h:#define HZ      CONFIG_OMAP_32K_TIMER_HZ
arch/arm/plat-omap/Kconfig:config OMAP_32K_TIMER
arch/arm/plat-omap/Kconfig:config OMAP_32K_TIMER_HZ
arch/arm/plat-omap/Kconfig:     depends on OMAP_32K_TIMER
arch/arm/Kconfig:       default OMAP_32K_TIMER_HZ if ARCH_OMAP && OMAP_32K_TIMER



Thanks,
Vaibhav

> Kevin
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

"Hiremath, Vaibhav" <hvaibhav@ti.com> writes:

> On Tue, Jan 24, 2012 at 05:08:50, Hilman, Kevin wrote:
>> Vaibhav Hiremath <hvaibhav@ti.com> writes:
>> 
>> > OMAP device has 32k-sync timer which is currently used as a
>> > clocksource in the kernel (omap2plus_defconfig).
>> > The current implementation uses compile time selection between
>> > gp-timer and 32k-sync timer, which breaks multi-omap build for
>> > the devices like AM33xx, where 32k-sync timer is not available.
>> >
>> > So use hwmod database lookup mechanism, through which at run-time
>> > we can identify availability of 32k-sync timer on the device,
>> > else fall back to gp-timer.
>> 
>> With the runtime detection & fallback, I suggest also removing the
>> Kconfig choice between the two as well.
>> 
> Kevin,
>
> Actually I thought of cleaning whole 32KTIMER related code,
> but then realized that, it would be major cleanup, since
> it is being used in lot of places.
>
> So let's not block this patch-series for this further cleanup.
> I will work on cleaning up the complete 32KTIMER macro and 
> submit the patches.

OK, Tony can make the call.

Kevin

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

"Hiremath, Vaibhav" <hvaibhav@ti.com> writes:

> On Tue, Jan 24, 2012 at 05:08:50, Hilman, Kevin wrote:
>> Vaibhav Hiremath <hvaibhav@ti.com> writes:
>> 
>> > OMAP device has 32k-sync timer which is currently used as a
>> > clocksource in the kernel (omap2plus_defconfig).
>> > The current implementation uses compile time selection between
>> > gp-timer and 32k-sync timer, which breaks multi-omap build for
>> > the devices like AM33xx, where 32k-sync timer is not available.
>> >
>> > So use hwmod database lookup mechanism, through which at run-time
>> > we can identify availability of 32k-sync timer on the device,
>> > else fall back to gp-timer.
>> 
>> With the runtime detection & fallback, I suggest also removing the
>> Kconfig choice between the two as well.
>> 
> Kevin,
>
> Actually I thought of cleaning whole 32KTIMER related code,
> but then realized that, it would be major cleanup, since
> it is being used in lot of places.
>
> So let's not block this patch-series for this further cleanup.
> I will work on cleaning up the complete 32KTIMER macro and 
> submit the patches.

OK, Tony can make the call.

Kevin

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Jan 24, 2012 at 23:17:56, Hilman, Kevin wrote:
> "Hiremath, Vaibhav" <hvaibhav@ti.com> writes:
> 
> > On Tue, Jan 24, 2012 at 05:08:50, Hilman, Kevin wrote:
> >> Vaibhav Hiremath <hvaibhav@ti.com> writes:
> >> 
> >> > OMAP device has 32k-sync timer which is currently used as a
> >> > clocksource in the kernel (omap2plus_defconfig).
> >> > The current implementation uses compile time selection between
> >> > gp-timer and 32k-sync timer, which breaks multi-omap build for
> >> > the devices like AM33xx, where 32k-sync timer is not available.
> >> >
> >> > So use hwmod database lookup mechanism, through which at run-time
> >> > we can identify availability of 32k-sync timer on the device,
> >> > else fall back to gp-timer.
> >> 
> >> With the runtime detection & fallback, I suggest also removing the
> >> Kconfig choice between the two as well.
> >> 
> > Kevin,
> >
> > Actually I thought of cleaning whole 32KTIMER related code,
> > but then realized that, it would be major cleanup, since
> > it is being used in lot of places.
> >
> > So let's not block this patch-series for this further cleanup.
> > I will work on cleaning up the complete 32KTIMER macro and 
> > submit the patches.
> 
> OK, Tony can make the call.
> 
Tony,

Can this also get merged?

Thanks,
Vaibhav

> Kevin
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Jan 24, 2012 at 23:17:56, Hilman, Kevin wrote:
> "Hiremath, Vaibhav" <hvaibhav@ti.com> writes:
> 
> > On Tue, Jan 24, 2012 at 05:08:50, Hilman, Kevin wrote:
> >> Vaibhav Hiremath <hvaibhav@ti.com> writes:
> >> 
> >> > OMAP device has 32k-sync timer which is currently used as a
> >> > clocksource in the kernel (omap2plus_defconfig).
> >> > The current implementation uses compile time selection between
> >> > gp-timer and 32k-sync timer, which breaks multi-omap build for
> >> > the devices like AM33xx, where 32k-sync timer is not available.
> >> >
> >> > So use hwmod database lookup mechanism, through which at run-time
> >> > we can identify availability of 32k-sync timer on the device,
> >> > else fall back to gp-timer.
> >> 
> >> With the runtime detection & fallback, I suggest also removing the
> >> Kconfig choice between the two as well.
> >> 
> > Kevin,
> >
> > Actually I thought of cleaning whole 32KTIMER related code,
> > but then realized that, it would be major cleanup, since
> > it is being used in lot of places.
> >
> > So let's not block this patch-series for this further cleanup.
> > I will work on cleaning up the complete 32KTIMER macro and 
> > submit the patches.
> 
> OK, Tony can make the call.
> 
Tony,

Can this also get merged?

Thanks,
Vaibhav

> Kevin
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Tony Lindgren]

Hi,

* Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> OMAP device has 32k-sync timer which is currently used as a
> clocksource in the kernel (omap2plus_defconfig).
> The current implementation uses compile time selection between
> gp-timer and 32k-sync timer, which breaks multi-omap build for
> the devices like AM33xx, where 32k-sync timer is not available.
> 
> So use hwmod database lookup mechanism, through which at run-time
> we can identify availability of 32k-sync timer on the device,
> else fall back to gp-timer.
...

> --- a/arch/arm/plat-omap/counter_32k.c
> +++ b/arch/arm/plat-omap/counter_32k.c
> @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
>  
>  int __init omap_init_clocksource_32k(void)
>  {
> -	static char err[] __initdata = KERN_ERR
> -			"%s: can't register clocksource!\n";
> -
> -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> -		u32 pbase;
> -		unsigned long size = SZ_4K;
> -		void __iomem *base;
> -		struct clk *sync_32k_ick;
> -
> -		if (cpu_is_omap16xx()) {
> -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> -			size = SZ_1K;
> -		} else if (cpu_is_omap2420())
> -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> -		else if (cpu_is_omap2430())
> -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> -		else if (cpu_is_omap34xx())
> -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> -		else if (cpu_is_omap44xx())
> -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> -		else
> +	u32 pbase;
> +	unsigned long size = SZ_4K;
> +	void __iomem *base;
> +	struct clk *sync_32k_ick;
> +
> +	if (cpu_is_omap16xx()) {
> +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> +		size = SZ_1K;
> +	} else if (cpu_class_is_omap2()) {
> +		struct omap_hwmod *oh;
> +		const char *oh_name = "counter_32k";
> +
> +		oh = omap_hwmod_lookup(oh_name);
> +		if (!oh || oh->slaves_cnt == 0) {
> +			pr_err("Could not lookup %s hwmod\n", oh_name);
>  			return -ENODEV;
> +		}
> +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> +	} else {
> +		return -ENODEV;
> +	}

How about have separate omap1 and omap2+ init functions that
call a common function and passes the pbase as a parameter?

That way we can get rid of the cpu_is_omapxxxx tests here.

Regards,

Tony 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Tony Lindgren]

Hi,

* Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> OMAP device has 32k-sync timer which is currently used as a
> clocksource in the kernel (omap2plus_defconfig).
> The current implementation uses compile time selection between
> gp-timer and 32k-sync timer, which breaks multi-omap build for
> the devices like AM33xx, where 32k-sync timer is not available.
> 
> So use hwmod database lookup mechanism, through which at run-time
> we can identify availability of 32k-sync timer on the device,
> else fall back to gp-timer.
...

> --- a/arch/arm/plat-omap/counter_32k.c
> +++ b/arch/arm/plat-omap/counter_32k.c
> @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
>  
>  int __init omap_init_clocksource_32k(void)
>  {
> -	static char err[] __initdata = KERN_ERR
> -			"%s: can't register clocksource!\n";
> -
> -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> -		u32 pbase;
> -		unsigned long size = SZ_4K;
> -		void __iomem *base;
> -		struct clk *sync_32k_ick;
> -
> -		if (cpu_is_omap16xx()) {
> -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> -			size = SZ_1K;
> -		} else if (cpu_is_omap2420())
> -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> -		else if (cpu_is_omap2430())
> -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> -		else if (cpu_is_omap34xx())
> -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> -		else if (cpu_is_omap44xx())
> -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> -		else
> +	u32 pbase;
> +	unsigned long size = SZ_4K;
> +	void __iomem *base;
> +	struct clk *sync_32k_ick;
> +
> +	if (cpu_is_omap16xx()) {
> +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> +		size = SZ_1K;
> +	} else if (cpu_class_is_omap2()) {
> +		struct omap_hwmod *oh;
> +		const char *oh_name = "counter_32k";
> +
> +		oh = omap_hwmod_lookup(oh_name);
> +		if (!oh || oh->slaves_cnt == 0) {
> +			pr_err("Could not lookup %s hwmod\n", oh_name);
>  			return -ENODEV;
> +		}
> +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> +	} else {
> +		return -ENODEV;
> +	}

How about have separate omap1 and omap2+ init functions that
call a common function and passes the pbase as a parameter?

That way we can get rid of the cpu_is_omapxxxx tests here.

Regards,

Tony 

Re: [PATCH 2/3] ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common header

[Tony Lindgren]

* Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> Add missing idle_st bit for 32k-sync timer into the prcm-common
> header file, required for hwmod data.

These should be queued by Paul when the related hwmod changes
are done.

Regards,

Tony
 
> Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
> Cc: Felipe Balbi <balbi@ti.com>
> Cc: Benoit Cousson <b-cousson@ti.com>
> Cc: Tony Lindgren <tony@atomide.com>
> Cc: Paul Walmsley <paul@pwsan.com>
> ---
>  arch/arm/mach-omap2/prcm-common.h |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/prcm-common.h b/arch/arm/mach-omap2/prcm-common.h
> index 5aa5435..29955d5 100644
> --- a/arch/arm/mach-omap2/prcm-common.h
> +++ b/arch/arm/mach-omap2/prcm-common.h
> @@ -177,6 +177,8 @@
>  /* PM_WKST_WKUP, CM_IDLEST_WKUP shared bits */
>  #define OMAP24XX_ST_GPIOS_SHIFT				2
>  #define OMAP24XX_ST_GPIOS_MASK				(1 << 2)
> +#define OMAP24XX_ST_32KSYNC_SHIFT			1
> +#define OMAP24XX_ST_32KSYNC_MASK			(1 << 1)
>  #define OMAP24XX_ST_GPT1_SHIFT				0
>  #define OMAP24XX_ST_GPT1_MASK				(1 << 0)
>  
> @@ -307,6 +309,8 @@
>  #define OMAP3430_ST_SR1_MASK				(1 << 6)
>  #define OMAP3430_ST_GPIO1_SHIFT				3
>  #define OMAP3430_ST_GPIO1_MASK				(1 << 3)
> +#define OMAP3430_ST_32KSYNC_SHIFT			2
> +#define OMAP3430_ST_32KSYNC_MASK			(1 << 2)
>  #define OMAP3430_ST_GPT12_SHIFT				1
>  #define OMAP3430_ST_GPT12_MASK				(1 << 1)
>  #define OMAP3430_ST_GPT1_SHIFT				0
> -- 
> 1.7.0.4
> 

[PATCH 2/3] ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common header

[Tony Lindgren]

* Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> Add missing idle_st bit for 32k-sync timer into the prcm-common
> header file, required for hwmod data.

These should be queued by Paul when the related hwmod changes
are done.

Regards,

Tony
 
> Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
> Cc: Felipe Balbi <balbi@ti.com>
> Cc: Benoit Cousson <b-cousson@ti.com>
> Cc: Tony Lindgren <tony@atomide.com>
> Cc: Paul Walmsley <paul@pwsan.com>
> ---
>  arch/arm/mach-omap2/prcm-common.h |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/prcm-common.h b/arch/arm/mach-omap2/prcm-common.h
> index 5aa5435..29955d5 100644
> --- a/arch/arm/mach-omap2/prcm-common.h
> +++ b/arch/arm/mach-omap2/prcm-common.h
> @@ -177,6 +177,8 @@
>  /* PM_WKST_WKUP, CM_IDLEST_WKUP shared bits */
>  #define OMAP24XX_ST_GPIOS_SHIFT				2
>  #define OMAP24XX_ST_GPIOS_MASK				(1 << 2)
> +#define OMAP24XX_ST_32KSYNC_SHIFT			1
> +#define OMAP24XX_ST_32KSYNC_MASK			(1 << 1)
>  #define OMAP24XX_ST_GPT1_SHIFT				0
>  #define OMAP24XX_ST_GPT1_MASK				(1 << 0)
>  
> @@ -307,6 +309,8 @@
>  #define OMAP3430_ST_SR1_MASK				(1 << 6)
>  #define OMAP3430_ST_GPIO1_SHIFT				3
>  #define OMAP3430_ST_GPIO1_MASK				(1 << 3)
> +#define OMAP3430_ST_32KSYNC_SHIFT			2
> +#define OMAP3430_ST_32KSYNC_MASK			(1 << 2)
>  #define OMAP3430_ST_GPT12_SHIFT				1
>  #define OMAP3430_ST_GPT12_MASK				(1 << 1)
>  #define OMAP3430_ST_GPT1_SHIFT				0
> -- 
> 1.7.0.4
> 

Re: [PATCH 0/3] ARM: OMAP1/2+: 32k-timer: Add hwmod lookup for 32k-timer

[Tony Lindgren]

* Hiremath, Vaibhav <hvaibhav@ti.com> [120123 00:16]:
> On Thu, Jan 19, 2012 at 19:58:21, Hiremath, Vaibhav wrote:
> > This patch series cleans up the existing 32k-sync timer implementation
> > without any major code change and adds hwmod lookup for omap2+ devices,
> > if lookup fails then fall back to gp-timer.
...
 
> Tony,
> 
> If there are no review comments, can this be merged?

Made a minor comment on the first patch, it would be nice to get
that clean-up merged. The other two depend on some some hwmod
data shrinkage by Paul..

Regards,

Tony

[PATCH 0/3] ARM: OMAP1/2+: 32k-timer: Add hwmod lookup for 32k-timer

[Tony Lindgren]

* Hiremath, Vaibhav <hvaibhav@ti.com> [120123 00:16]:
> On Thu, Jan 19, 2012 at 19:58:21, Hiremath, Vaibhav wrote:
> > This patch series cleans up the existing 32k-sync timer implementation
> > without any major code change and adds hwmod lookup for omap2+ devices,
> > if lookup fails then fall back to gp-timer.
...
 
> Tony,
> 
> If there are no review comments, can this be merged?

Made a minor comment on the first patch, it would be nice to get
that clean-up merged. The other two depend on some some hwmod
data shrinkage by Paul..

Regards,

Tony

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> Hi,
> 
> * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > OMAP device has 32k-sync timer which is currently used as a
> > clocksource in the kernel (omap2plus_defconfig).
> > The current implementation uses compile time selection between
> > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > the devices like AM33xx, where 32k-sync timer is not available.
> > 
> > So use hwmod database lookup mechanism, through which at run-time
> > we can identify availability of 32k-sync timer on the device,
> > else fall back to gp-timer.
> ...
> 
> > --- a/arch/arm/plat-omap/counter_32k.c
> > +++ b/arch/arm/plat-omap/counter_32k.c
> > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> >  
> >  int __init omap_init_clocksource_32k(void)
> >  {
> > -	static char err[] __initdata = KERN_ERR
> > -			"%s: can't register clocksource!\n";
> > -
> > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > -		u32 pbase;
> > -		unsigned long size = SZ_4K;
> > -		void __iomem *base;
> > -		struct clk *sync_32k_ick;
> > -
> > -		if (cpu_is_omap16xx()) {
> > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > -			size = SZ_1K;
> > -		} else if (cpu_is_omap2420())
> > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap2430())
> > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap34xx())
> > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap44xx())
> > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > -		else
> > +	u32 pbase;
> > +	unsigned long size = SZ_4K;
> > +	void __iomem *base;
> > +	struct clk *sync_32k_ick;
> > +
> > +	if (cpu_is_omap16xx()) {
> > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > +		size = SZ_1K;
> > +	} else if (cpu_class_is_omap2()) {
> > +		struct omap_hwmod *oh;
> > +		const char *oh_name = "counter_32k";
> > +
> > +		oh = omap_hwmod_lookup(oh_name);
> > +		if (!oh || oh->slaves_cnt == 0) {
> > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> >  			return -ENODEV;
> > +		}
> > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > +	} else {
> > +		return -ENODEV;
> > +	}
> 
> How about have separate omap1 and omap2+ init functions that
> call a common function and passes the pbase as a parameter?
> 
> That way we can get rid of the cpu_is_omapxxxx tests here.
> 

Ok, let me clean this code accordingly  and submit the next version.

Thanks,
Vaibhav

> Regards,
> 
> Tony 
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> Hi,
> 
> * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > OMAP device has 32k-sync timer which is currently used as a
> > clocksource in the kernel (omap2plus_defconfig).
> > The current implementation uses compile time selection between
> > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > the devices like AM33xx, where 32k-sync timer is not available.
> > 
> > So use hwmod database lookup mechanism, through which at run-time
> > we can identify availability of 32k-sync timer on the device,
> > else fall back to gp-timer.
> ...
> 
> > --- a/arch/arm/plat-omap/counter_32k.c
> > +++ b/arch/arm/plat-omap/counter_32k.c
> > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> >  
> >  int __init omap_init_clocksource_32k(void)
> >  {
> > -	static char err[] __initdata = KERN_ERR
> > -			"%s: can't register clocksource!\n";
> > -
> > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > -		u32 pbase;
> > -		unsigned long size = SZ_4K;
> > -		void __iomem *base;
> > -		struct clk *sync_32k_ick;
> > -
> > -		if (cpu_is_omap16xx()) {
> > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > -			size = SZ_1K;
> > -		} else if (cpu_is_omap2420())
> > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap2430())
> > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap34xx())
> > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap44xx())
> > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > -		else
> > +	u32 pbase;
> > +	unsigned long size = SZ_4K;
> > +	void __iomem *base;
> > +	struct clk *sync_32k_ick;
> > +
> > +	if (cpu_is_omap16xx()) {
> > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > +		size = SZ_1K;
> > +	} else if (cpu_class_is_omap2()) {
> > +		struct omap_hwmod *oh;
> > +		const char *oh_name = "counter_32k";
> > +
> > +		oh = omap_hwmod_lookup(oh_name);
> > +		if (!oh || oh->slaves_cnt == 0) {
> > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> >  			return -ENODEV;
> > +		}
> > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > +	} else {
> > +		return -ENODEV;
> > +	}
> 
> How about have separate omap1 and omap2+ init functions that
> call a common function and passes the pbase as a parameter?
> 
> That way we can get rid of the cpu_is_omapxxxx tests here.
> 

Ok, let me clean this code accordingly  and submit the next version.

Thanks,
Vaibhav

> Regards,
> 
> Tony 
> 

RE: [PATCH 2/3] ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common header

[Hiremath, Vaibhav]

On Tue, Mar 06, 2012 at 04:26:40, Tony Lindgren wrote:
> * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > Add missing idle_st bit for 32k-sync timer into the prcm-common
> > header file, required for hwmod data.
> 
> These should be queued by Paul when the related hwmod changes
> are done.
> 

Paul,

Can you queue this up into your next-branch?

Thanks,
Vaibhav


> Regards,
> 
> Tony
>  
> > Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
> > Cc: Felipe Balbi <balbi@ti.com>
> > Cc: Benoit Cousson <b-cousson@ti.com>
> > Cc: Tony Lindgren <tony@atomide.com>
> > Cc: Paul Walmsley <paul@pwsan.com>
> > ---
> >  arch/arm/mach-omap2/prcm-common.h |    4 ++++
> >  1 files changed, 4 insertions(+), 0 deletions(-)
> > 
> > diff --git a/arch/arm/mach-omap2/prcm-common.h b/arch/arm/mach-omap2/prcm-common.h
> > index 5aa5435..29955d5 100644
> > --- a/arch/arm/mach-omap2/prcm-common.h
> > +++ b/arch/arm/mach-omap2/prcm-common.h
> > @@ -177,6 +177,8 @@
> >  /* PM_WKST_WKUP, CM_IDLEST_WKUP shared bits */
> >  #define OMAP24XX_ST_GPIOS_SHIFT				2
> >  #define OMAP24XX_ST_GPIOS_MASK				(1 << 2)
> > +#define OMAP24XX_ST_32KSYNC_SHIFT			1
> > +#define OMAP24XX_ST_32KSYNC_MASK			(1 << 1)
> >  #define OMAP24XX_ST_GPT1_SHIFT				0
> >  #define OMAP24XX_ST_GPT1_MASK				(1 << 0)
> >  
> > @@ -307,6 +309,8 @@
> >  #define OMAP3430_ST_SR1_MASK				(1 << 6)
> >  #define OMAP3430_ST_GPIO1_SHIFT				3
> >  #define OMAP3430_ST_GPIO1_MASK				(1 << 3)
> > +#define OMAP3430_ST_32KSYNC_SHIFT			2
> > +#define OMAP3430_ST_32KSYNC_MASK			(1 << 2)
> >  #define OMAP3430_ST_GPT12_SHIFT				1
> >  #define OMAP3430_ST_GPT12_MASK				(1 << 1)
> >  #define OMAP3430_ST_GPT1_SHIFT				0
> > -- 
> > 1.7.0.4
> > 
> 

[PATCH 2/3] ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common header

[Hiremath, Vaibhav]

On Tue, Mar 06, 2012 at 04:26:40, Tony Lindgren wrote:
> * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > Add missing idle_st bit for 32k-sync timer into the prcm-common
> > header file, required for hwmod data.
> 
> These should be queued by Paul when the related hwmod changes
> are done.
> 

Paul,

Can you queue this up into your next-branch?

Thanks,
Vaibhav


> Regards,
> 
> Tony
>  
> > Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
> > Cc: Felipe Balbi <balbi@ti.com>
> > Cc: Benoit Cousson <b-cousson@ti.com>
> > Cc: Tony Lindgren <tony@atomide.com>
> > Cc: Paul Walmsley <paul@pwsan.com>
> > ---
> >  arch/arm/mach-omap2/prcm-common.h |    4 ++++
> >  1 files changed, 4 insertions(+), 0 deletions(-)
> > 
> > diff --git a/arch/arm/mach-omap2/prcm-common.h b/arch/arm/mach-omap2/prcm-common.h
> > index 5aa5435..29955d5 100644
> > --- a/arch/arm/mach-omap2/prcm-common.h
> > +++ b/arch/arm/mach-omap2/prcm-common.h
> > @@ -177,6 +177,8 @@
> >  /* PM_WKST_WKUP, CM_IDLEST_WKUP shared bits */
> >  #define OMAP24XX_ST_GPIOS_SHIFT				2
> >  #define OMAP24XX_ST_GPIOS_MASK				(1 << 2)
> > +#define OMAP24XX_ST_32KSYNC_SHIFT			1
> > +#define OMAP24XX_ST_32KSYNC_MASK			(1 << 1)
> >  #define OMAP24XX_ST_GPT1_SHIFT				0
> >  #define OMAP24XX_ST_GPT1_MASK				(1 << 0)
> >  
> > @@ -307,6 +309,8 @@
> >  #define OMAP3430_ST_SR1_MASK				(1 << 6)
> >  #define OMAP3430_ST_GPIO1_SHIFT				3
> >  #define OMAP3430_ST_GPIO1_MASK				(1 << 3)
> > +#define OMAP3430_ST_32KSYNC_SHIFT			2
> > +#define OMAP3430_ST_32KSYNC_MASK			(1 << 2)
> >  #define OMAP3430_ST_GPT12_SHIFT				1
> >  #define OMAP3430_ST_GPT12_MASK				(1 << 1)
> >  #define OMAP3430_ST_GPT1_SHIFT				0
> > -- 
> > 1.7.0.4
> > 
> 

RE: [PATCH 0/3] ARM: OMAP1/2+: 32k-timer: Add hwmod lookup for 32k-timer

[Hiremath, Vaibhav]

On Tue, Mar 06, 2012 at 04:27:52, Tony Lindgren wrote:
> * Hiremath, Vaibhav <hvaibhav@ti.com> [120123 00:16]:
> > On Thu, Jan 19, 2012 at 19:58:21, Hiremath, Vaibhav wrote:
> > > This patch series cleans up the existing 32k-sync timer implementation
> > > without any major code change and adds hwmod lookup for omap2+ devices,
> > > if lookup fails then fall back to gp-timer.
> ...
>  
> > Tony,
> > 
> > If there are no review comments, can this be merged?
> 
> Made a minor comment on the first patch, it would be nice to get
> that clean-up merged. The other two depend on some some hwmod
> data shrinkage by Paul..
> 

Working on it, will be submitting next version soon.

Thanks,
Vaibhav

> Regards,
> 
> Tony
> 

[PATCH 0/3] ARM: OMAP1/2+: 32k-timer: Add hwmod lookup for 32k-timer

[Hiremath, Vaibhav]

On Tue, Mar 06, 2012 at 04:27:52, Tony Lindgren wrote:
> * Hiremath, Vaibhav <hvaibhav@ti.com> [120123 00:16]:
> > On Thu, Jan 19, 2012 at 19:58:21, Hiremath, Vaibhav wrote:
> > > This patch series cleans up the existing 32k-sync timer implementation
> > > without any major code change and adds hwmod lookup for omap2+ devices,
> > > if lookup fails then fall back to gp-timer.
> ...
>  
> > Tony,
> > 
> > If there are no review comments, can this be merged?
> 
> Made a minor comment on the first patch, it would be nice to get
> that clean-up merged. The other two depend on some some hwmod
> data shrinkage by Paul..
> 

Working on it, will be submitting next version soon.

Thanks,
Vaibhav

> Regards,
> 
> Tony
> 

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> Hi,
> 
> * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > OMAP device has 32k-sync timer which is currently used as a
> > clocksource in the kernel (omap2plus_defconfig).
> > The current implementation uses compile time selection between
> > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > the devices like AM33xx, where 32k-sync timer is not available.
> > 
> > So use hwmod database lookup mechanism, through which at run-time
> > we can identify availability of 32k-sync timer on the device,
> > else fall back to gp-timer.
> ...
> 
> > --- a/arch/arm/plat-omap/counter_32k.c
> > +++ b/arch/arm/plat-omap/counter_32k.c
> > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> >  
> >  int __init omap_init_clocksource_32k(void)
> >  {
> > -	static char err[] __initdata = KERN_ERR
> > -			"%s: can't register clocksource!\n";
> > -
> > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > -		u32 pbase;
> > -		unsigned long size = SZ_4K;
> > -		void __iomem *base;
> > -		struct clk *sync_32k_ick;
> > -
> > -		if (cpu_is_omap16xx()) {
> > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > -			size = SZ_1K;
> > -		} else if (cpu_is_omap2420())
> > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap2430())
> > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap34xx())
> > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap44xx())
> > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > -		else
> > +	u32 pbase;
> > +	unsigned long size = SZ_4K;
> > +	void __iomem *base;
> > +	struct clk *sync_32k_ick;
> > +
> > +	if (cpu_is_omap16xx()) {
> > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > +		size = SZ_1K;
> > +	} else if (cpu_class_is_omap2()) {
> > +		struct omap_hwmod *oh;
> > +		const char *oh_name = "counter_32k";
> > +
> > +		oh = omap_hwmod_lookup(oh_name);
> > +		if (!oh || oh->slaves_cnt == 0) {
> > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> >  			return -ENODEV;
> > +		}
> > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > +	} else {
> > +		return -ENODEV;
> > +	}
> 
> How about have separate omap1 and omap2+ init functions that
> call a common function and passes the pbase as a parameter?
> 
> That way we can get rid of the cpu_is_omapxxxx tests here.
> 

Tony,

In the morning, I replied very soon, without much thinking...

Just now I started working on the patch, I was just reviewing the code, 
and I felt that, it is unnecessary to split the code between omap1 and 
omap2+.

The reason is,

Currently Only OMAP16xx base-address is hardcoded with cpu_is_omap16xx() 
macro, For all other omap family of devices the complete information is fetched from HWDMO api's/data.

Thanks,
Vaibhav

> Regards,
> 
> Tony 
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> Hi,
> 
> * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > OMAP device has 32k-sync timer which is currently used as a
> > clocksource in the kernel (omap2plus_defconfig).
> > The current implementation uses compile time selection between
> > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > the devices like AM33xx, where 32k-sync timer is not available.
> > 
> > So use hwmod database lookup mechanism, through which at run-time
> > we can identify availability of 32k-sync timer on the device,
> > else fall back to gp-timer.
> ...
> 
> > --- a/arch/arm/plat-omap/counter_32k.c
> > +++ b/arch/arm/plat-omap/counter_32k.c
> > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> >  
> >  int __init omap_init_clocksource_32k(void)
> >  {
> > -	static char err[] __initdata = KERN_ERR
> > -			"%s: can't register clocksource!\n";
> > -
> > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > -		u32 pbase;
> > -		unsigned long size = SZ_4K;
> > -		void __iomem *base;
> > -		struct clk *sync_32k_ick;
> > -
> > -		if (cpu_is_omap16xx()) {
> > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > -			size = SZ_1K;
> > -		} else if (cpu_is_omap2420())
> > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap2430())
> > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap34xx())
> > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap44xx())
> > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > -		else
> > +	u32 pbase;
> > +	unsigned long size = SZ_4K;
> > +	void __iomem *base;
> > +	struct clk *sync_32k_ick;
> > +
> > +	if (cpu_is_omap16xx()) {
> > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > +		size = SZ_1K;
> > +	} else if (cpu_class_is_omap2()) {
> > +		struct omap_hwmod *oh;
> > +		const char *oh_name = "counter_32k";
> > +
> > +		oh = omap_hwmod_lookup(oh_name);
> > +		if (!oh || oh->slaves_cnt == 0) {
> > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> >  			return -ENODEV;
> > +		}
> > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > +	} else {
> > +		return -ENODEV;
> > +	}
> 
> How about have separate omap1 and omap2+ init functions that
> call a common function and passes the pbase as a parameter?
> 
> That way we can get rid of the cpu_is_omapxxxx tests here.
> 

Tony,

In the morning, I replied very soon, without much thinking...

Just now I started working on the patch, I was just reviewing the code, 
and I felt that, it is unnecessary to split the code between omap1 and 
omap2+.

The reason is,

Currently Only OMAP16xx base-address is hardcoded with cpu_is_omap16xx() 
macro, For all other omap family of devices the complete information is fetched from HWDMO api's/data.

Thanks,
Vaibhav

> Regards,
> 
> Tony 
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 3285 bytes --]

On Fri, Mar 09, 2012 at 05:58:00PM +0000, Hiremath, Vaibhav wrote:
> On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> > Hi,
> > 
> > * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > > OMAP device has 32k-sync timer which is currently used as a
> > > clocksource in the kernel (omap2plus_defconfig).
> > > The current implementation uses compile time selection between
> > > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > > the devices like AM33xx, where 32k-sync timer is not available.
> > > 
> > > So use hwmod database lookup mechanism, through which at run-time
> > > we can identify availability of 32k-sync timer on the device,
> > > else fall back to gp-timer.
> > ...
> > 
> > > --- a/arch/arm/plat-omap/counter_32k.c
> > > +++ b/arch/arm/plat-omap/counter_32k.c
> > > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> > >  
> > >  int __init omap_init_clocksource_32k(void)
> > >  {
> > > -	static char err[] __initdata = KERN_ERR
> > > -			"%s: can't register clocksource!\n";
> > > -
> > > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > > -		u32 pbase;
> > > -		unsigned long size = SZ_4K;
> > > -		void __iomem *base;
> > > -		struct clk *sync_32k_ick;
> > > -
> > > -		if (cpu_is_omap16xx()) {
> > > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > -			size = SZ_1K;
> > > -		} else if (cpu_is_omap2420())
> > > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > > -		else if (cpu_is_omap2430())
> > > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > > -		else if (cpu_is_omap34xx())
> > > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > > -		else if (cpu_is_omap44xx())
> > > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > > -		else
> > > +	u32 pbase;
> > > +	unsigned long size = SZ_4K;
> > > +	void __iomem *base;
> > > +	struct clk *sync_32k_ick;
> > > +
> > > +	if (cpu_is_omap16xx()) {
> > > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > +		size = SZ_1K;
> > > +	} else if (cpu_class_is_omap2()) {
> > > +		struct omap_hwmod *oh;
> > > +		const char *oh_name = "counter_32k";
> > > +
> > > +		oh = omap_hwmod_lookup(oh_name);
> > > +		if (!oh || oh->slaves_cnt == 0) {
> > > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> > >  			return -ENODEV;
> > > +		}
> > > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > > +	} else {
> > > +		return -ENODEV;
> > > +	}
> > 
> > How about have separate omap1 and omap2+ init functions that
> > call a common function and passes the pbase as a parameter?
> > 
> > That way we can get rid of the cpu_is_omapxxxx tests here.
> > 
> 
> Tony,
> 
> In the morning, I replied very soon, without much thinking...
> 
> Just now I started working on the patch, I was just reviewing the code, 
> and I felt that, it is unnecessary to split the code between omap1 and 
> omap2+.
> 
> The reason is,
> 
> Currently Only OMAP16xx base-address is hardcoded with
> cpu_is_omap16xx() macro, For all other omap family of devices the
> complete information is fetched from HWDMO api's/data.

In that case, why don't you create the platform_device by hand on
arch/arm/mach-omap1/devices.c and move the omap2+ (which is based on
hwmod) to arch/arm/mach-omap2/devices.c ?

-- 
balbi

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Felipe Balbi]

On Fri, Mar 09, 2012 at 05:58:00PM +0000, Hiremath, Vaibhav wrote:
> On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> > Hi,
> > 
> > * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > > OMAP device has 32k-sync timer which is currently used as a
> > > clocksource in the kernel (omap2plus_defconfig).
> > > The current implementation uses compile time selection between
> > > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > > the devices like AM33xx, where 32k-sync timer is not available.
> > > 
> > > So use hwmod database lookup mechanism, through which at run-time
> > > we can identify availability of 32k-sync timer on the device,
> > > else fall back to gp-timer.
> > ...
> > 
> > > --- a/arch/arm/plat-omap/counter_32k.c
> > > +++ b/arch/arm/plat-omap/counter_32k.c
> > > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> > >  
> > >  int __init omap_init_clocksource_32k(void)
> > >  {
> > > -	static char err[] __initdata = KERN_ERR
> > > -			"%s: can't register clocksource!\n";
> > > -
> > > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > > -		u32 pbase;
> > > -		unsigned long size = SZ_4K;
> > > -		void __iomem *base;
> > > -		struct clk *sync_32k_ick;
> > > -
> > > -		if (cpu_is_omap16xx()) {
> > > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > -			size = SZ_1K;
> > > -		} else if (cpu_is_omap2420())
> > > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > > -		else if (cpu_is_omap2430())
> > > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > > -		else if (cpu_is_omap34xx())
> > > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > > -		else if (cpu_is_omap44xx())
> > > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > > -		else
> > > +	u32 pbase;
> > > +	unsigned long size = SZ_4K;
> > > +	void __iomem *base;
> > > +	struct clk *sync_32k_ick;
> > > +
> > > +	if (cpu_is_omap16xx()) {
> > > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > +		size = SZ_1K;
> > > +	} else if (cpu_class_is_omap2()) {
> > > +		struct omap_hwmod *oh;
> > > +		const char *oh_name = "counter_32k";
> > > +
> > > +		oh = omap_hwmod_lookup(oh_name);
> > > +		if (!oh || oh->slaves_cnt == 0) {
> > > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> > >  			return -ENODEV;
> > > +		}
> > > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > > +	} else {
> > > +		return -ENODEV;
> > > +	}
> > 
> > How about have separate omap1 and omap2+ init functions that
> > call a common function and passes the pbase as a parameter?
> > 
> > That way we can get rid of the cpu_is_omapxxxx tests here.
> > 
> 
> Tony,
> 
> In the morning, I replied very soon, without much thinking...
> 
> Just now I started working on the patch, I was just reviewing the code, 
> and I felt that, it is unnecessary to split the code between omap1 and 
> omap2+.
> 
> The reason is,
> 
> Currently Only OMAP16xx base-address is hardcoded with
> cpu_is_omap16xx() macro, For all other omap family of devices the
> complete information is fetched from HWDMO api's/data.

In that case, why don't you create the platform_device by hand on
arch/arm/mach-omap1/devices.c and move the omap2+ (which is based on
hwmod) to arch/arm/mach-omap2/devices.c ?

-- 
balbi
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RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Mon, Mar 12, 2012 at 15:09:24, Balbi, Felipe wrote:
> On Fri, Mar 09, 2012 at 05:58:00PM +0000, Hiremath, Vaibhav wrote:
> > On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> > > Hi,
> > > 
> > > * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > > > OMAP device has 32k-sync timer which is currently used as a
> > > > clocksource in the kernel (omap2plus_defconfig).
> > > > The current implementation uses compile time selection between
> > > > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > > > the devices like AM33xx, where 32k-sync timer is not available.
> > > > 
> > > > So use hwmod database lookup mechanism, through which at run-time
> > > > we can identify availability of 32k-sync timer on the device,
> > > > else fall back to gp-timer.
> > > ...
> > > 
> > > > --- a/arch/arm/plat-omap/counter_32k.c
> > > > +++ b/arch/arm/plat-omap/counter_32k.c
> > > > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> > > >  
> > > >  int __init omap_init_clocksource_32k(void)
> > > >  {
> > > > -	static char err[] __initdata = KERN_ERR
> > > > -			"%s: can't register clocksource!\n";
> > > > -
> > > > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > > > -		u32 pbase;
> > > > -		unsigned long size = SZ_4K;
> > > > -		void __iomem *base;
> > > > -		struct clk *sync_32k_ick;
> > > > -
> > > > -		if (cpu_is_omap16xx()) {
> > > > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > -			size = SZ_1K;
> > > > -		} else if (cpu_is_omap2420())
> > > > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > > > -		else if (cpu_is_omap2430())
> > > > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > > > -		else if (cpu_is_omap34xx())
> > > > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > > > -		else if (cpu_is_omap44xx())
> > > > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > > > -		else
> > > > +	u32 pbase;
> > > > +	unsigned long size = SZ_4K;
> > > > +	void __iomem *base;
> > > > +	struct clk *sync_32k_ick;
> > > > +
> > > > +	if (cpu_is_omap16xx()) {
> > > > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > +		size = SZ_1K;
> > > > +	} else if (cpu_class_is_omap2()) {
> > > > +		struct omap_hwmod *oh;
> > > > +		const char *oh_name = "counter_32k";
> > > > +
> > > > +		oh = omap_hwmod_lookup(oh_name);
> > > > +		if (!oh || oh->slaves_cnt == 0) {
> > > > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> > > >  			return -ENODEV;
> > > > +		}
> > > > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > > > +	} else {
> > > > +		return -ENODEV;
> > > > +	}
> > > 
> > > How about have separate omap1 and omap2+ init functions that
> > > call a common function and passes the pbase as a parameter?
> > > 
> > > That way we can get rid of the cpu_is_omapxxxx tests here.
> > > 
> > 
> > Tony,
> > 
> > In the morning, I replied very soon, without much thinking...
> > 
> > Just now I started working on the patch, I was just reviewing the code, 
> > and I felt that, it is unnecessary to split the code between omap1 and 
> > omap2+.
> > 
> > The reason is,
> > 
> > Currently Only OMAP16xx base-address is hardcoded with
> > cpu_is_omap16xx() macro, For all other omap family of devices the
> > complete information is fetched from HWDMO api's/data.
> 
> In that case, why don't you create the platform_device by hand on
> arch/arm/mach-omap1/devices.c and move the omap2+ (which is based on
> hwmod) to arch/arm/mach-omap2/devices.c ?
> 

Balbi,

32k_counter code is not a platform_device/driver, we don't build the 
any device here. We only need hwmod data to fetch the basic information like, 
base-address, size, etc...

And I am note sure whether we really intend to make it 
platform_device/driver thing.

Thanks,
Vaibhav

> -- 
> balbi
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Mon, Mar 12, 2012 at 15:09:24, Balbi, Felipe wrote:
> On Fri, Mar 09, 2012 at 05:58:00PM +0000, Hiremath, Vaibhav wrote:
> > On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> > > Hi,
> > > 
> > > * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > > > OMAP device has 32k-sync timer which is currently used as a
> > > > clocksource in the kernel (omap2plus_defconfig).
> > > > The current implementation uses compile time selection between
> > > > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > > > the devices like AM33xx, where 32k-sync timer is not available.
> > > > 
> > > > So use hwmod database lookup mechanism, through which at run-time
> > > > we can identify availability of 32k-sync timer on the device,
> > > > else fall back to gp-timer.
> > > ...
> > > 
> > > > --- a/arch/arm/plat-omap/counter_32k.c
> > > > +++ b/arch/arm/plat-omap/counter_32k.c
> > > > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> > > >  
> > > >  int __init omap_init_clocksource_32k(void)
> > > >  {
> > > > -	static char err[] __initdata = KERN_ERR
> > > > -			"%s: can't register clocksource!\n";
> > > > -
> > > > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > > > -		u32 pbase;
> > > > -		unsigned long size = SZ_4K;
> > > > -		void __iomem *base;
> > > > -		struct clk *sync_32k_ick;
> > > > -
> > > > -		if (cpu_is_omap16xx()) {
> > > > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > -			size = SZ_1K;
> > > > -		} else if (cpu_is_omap2420())
> > > > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > > > -		else if (cpu_is_omap2430())
> > > > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > > > -		else if (cpu_is_omap34xx())
> > > > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > > > -		else if (cpu_is_omap44xx())
> > > > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > > > -		else
> > > > +	u32 pbase;
> > > > +	unsigned long size = SZ_4K;
> > > > +	void __iomem *base;
> > > > +	struct clk *sync_32k_ick;
> > > > +
> > > > +	if (cpu_is_omap16xx()) {
> > > > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > +		size = SZ_1K;
> > > > +	} else if (cpu_class_is_omap2()) {
> > > > +		struct omap_hwmod *oh;
> > > > +		const char *oh_name = "counter_32k";
> > > > +
> > > > +		oh = omap_hwmod_lookup(oh_name);
> > > > +		if (!oh || oh->slaves_cnt == 0) {
> > > > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> > > >  			return -ENODEV;
> > > > +		}
> > > > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > > > +	} else {
> > > > +		return -ENODEV;
> > > > +	}
> > > 
> > > How about have separate omap1 and omap2+ init functions that
> > > call a common function and passes the pbase as a parameter?
> > > 
> > > That way we can get rid of the cpu_is_omapxxxx tests here.
> > > 
> > 
> > Tony,
> > 
> > In the morning, I replied very soon, without much thinking...
> > 
> > Just now I started working on the patch, I was just reviewing the code, 
> > and I felt that, it is unnecessary to split the code between omap1 and 
> > omap2+.
> > 
> > The reason is,
> > 
> > Currently Only OMAP16xx base-address is hardcoded with
> > cpu_is_omap16xx() macro, For all other omap family of devices the
> > complete information is fetched from HWDMO api's/data.
> 
> In that case, why don't you create the platform_device by hand on
> arch/arm/mach-omap1/devices.c and move the omap2+ (which is based on
> hwmod) to arch/arm/mach-omap2/devices.c ?
> 

Balbi,

32k_counter code is not a platform_device/driver, we don't build the 
any device here. We only need hwmod data to fetch the basic information like, 
base-address, size, etc...

And I am note sure whether we really intend to make it 
platform_device/driver thing.

Thanks,
Vaibhav

> -- 
> balbi
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 4185 bytes --]

Hi,

On Mon, Mar 12, 2012 at 09:48:20AM +0000, Hiremath, Vaibhav wrote:
> On Mon, Mar 12, 2012 at 15:09:24, Balbi, Felipe wrote:
> > On Fri, Mar 09, 2012 at 05:58:00PM +0000, Hiremath, Vaibhav wrote:
> > > On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> > > > Hi,
> > > > 
> > > > * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > > > > OMAP device has 32k-sync timer which is currently used as a
> > > > > clocksource in the kernel (omap2plus_defconfig).
> > > > > The current implementation uses compile time selection between
> > > > > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > > > > the devices like AM33xx, where 32k-sync timer is not available.
> > > > > 
> > > > > So use hwmod database lookup mechanism, through which at run-time
> > > > > we can identify availability of 32k-sync timer on the device,
> > > > > else fall back to gp-timer.
> > > > ...
> > > > 
> > > > > --- a/arch/arm/plat-omap/counter_32k.c
> > > > > +++ b/arch/arm/plat-omap/counter_32k.c
> > > > > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> > > > >  
> > > > >  int __init omap_init_clocksource_32k(void)
> > > > >  {
> > > > > -	static char err[] __initdata = KERN_ERR
> > > > > -			"%s: can't register clocksource!\n";
> > > > > -
> > > > > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > > > > -		u32 pbase;
> > > > > -		unsigned long size = SZ_4K;
> > > > > -		void __iomem *base;
> > > > > -		struct clk *sync_32k_ick;
> > > > > -
> > > > > -		if (cpu_is_omap16xx()) {
> > > > > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > > -			size = SZ_1K;
> > > > > -		} else if (cpu_is_omap2420())
> > > > > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > > > > -		else if (cpu_is_omap2430())
> > > > > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > > > > -		else if (cpu_is_omap34xx())
> > > > > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > > > > -		else if (cpu_is_omap44xx())
> > > > > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > > > > -		else
> > > > > +	u32 pbase;
> > > > > +	unsigned long size = SZ_4K;
> > > > > +	void __iomem *base;
> > > > > +	struct clk *sync_32k_ick;
> > > > > +
> > > > > +	if (cpu_is_omap16xx()) {
> > > > > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > > +		size = SZ_1K;
> > > > > +	} else if (cpu_class_is_omap2()) {
> > > > > +		struct omap_hwmod *oh;
> > > > > +		const char *oh_name = "counter_32k";
> > > > > +
> > > > > +		oh = omap_hwmod_lookup(oh_name);
> > > > > +		if (!oh || oh->slaves_cnt == 0) {
> > > > > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> > > > >  			return -ENODEV;
> > > > > +		}
> > > > > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > > > > +	} else {
> > > > > +		return -ENODEV;
> > > > > +	}
> > > > 
> > > > How about have separate omap1 and omap2+ init functions that
> > > > call a common function and passes the pbase as a parameter?
> > > > 
> > > > That way we can get rid of the cpu_is_omapxxxx tests here.
> > > > 
> > > 
> > > Tony,
> > > 
> > > In the morning, I replied very soon, without much thinking...
> > > 
> > > Just now I started working on the patch, I was just reviewing the code, 
> > > and I felt that, it is unnecessary to split the code between omap1 and 
> > > omap2+.
> > > 
> > > The reason is,
> > > 
> > > Currently Only OMAP16xx base-address is hardcoded with
> > > cpu_is_omap16xx() macro, For all other omap family of devices the
> > > complete information is fetched from HWDMO api's/data.
> > 
> > In that case, why don't you create the platform_device by hand on
> > arch/arm/mach-omap1/devices.c and move the omap2+ (which is based on
> > hwmod) to arch/arm/mach-omap2/devices.c ?
> > 
> 
> Balbi,
> 
> 32k_counter code is not a platform_device/driver, we don't build the 
> any device here. We only need hwmod data to fetch the basic information like, 
> base-address, size, etc...
> 
> And I am note sure whether we really intend to make it 
> platform_device/driver thing.

that's kinda weird... anyway, you can also pass base as argument to
omap_init_clocksource_32k()... dunno.

-- 
balbi

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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Felipe Balbi]

Hi,

On Mon, Mar 12, 2012 at 09:48:20AM +0000, Hiremath, Vaibhav wrote:
> On Mon, Mar 12, 2012 at 15:09:24, Balbi, Felipe wrote:
> > On Fri, Mar 09, 2012 at 05:58:00PM +0000, Hiremath, Vaibhav wrote:
> > > On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> > > > Hi,
> > > > 
> > > > * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > > > > OMAP device has 32k-sync timer which is currently used as a
> > > > > clocksource in the kernel (omap2plus_defconfig).
> > > > > The current implementation uses compile time selection between
> > > > > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > > > > the devices like AM33xx, where 32k-sync timer is not available.
> > > > > 
> > > > > So use hwmod database lookup mechanism, through which at run-time
> > > > > we can identify availability of 32k-sync timer on the device,
> > > > > else fall back to gp-timer.
> > > > ...
> > > > 
> > > > > --- a/arch/arm/plat-omap/counter_32k.c
> > > > > +++ b/arch/arm/plat-omap/counter_32k.c
> > > > > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> > > > >  
> > > > >  int __init omap_init_clocksource_32k(void)
> > > > >  {
> > > > > -	static char err[] __initdata = KERN_ERR
> > > > > -			"%s: can't register clocksource!\n";
> > > > > -
> > > > > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > > > > -		u32 pbase;
> > > > > -		unsigned long size = SZ_4K;
> > > > > -		void __iomem *base;
> > > > > -		struct clk *sync_32k_ick;
> > > > > -
> > > > > -		if (cpu_is_omap16xx()) {
> > > > > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > > -			size = SZ_1K;
> > > > > -		} else if (cpu_is_omap2420())
> > > > > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > > > > -		else if (cpu_is_omap2430())
> > > > > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > > > > -		else if (cpu_is_omap34xx())
> > > > > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > > > > -		else if (cpu_is_omap44xx())
> > > > > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > > > > -		else
> > > > > +	u32 pbase;
> > > > > +	unsigned long size = SZ_4K;
> > > > > +	void __iomem *base;
> > > > > +	struct clk *sync_32k_ick;
> > > > > +
> > > > > +	if (cpu_is_omap16xx()) {
> > > > > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > > +		size = SZ_1K;
> > > > > +	} else if (cpu_class_is_omap2()) {
> > > > > +		struct omap_hwmod *oh;
> > > > > +		const char *oh_name = "counter_32k";
> > > > > +
> > > > > +		oh = omap_hwmod_lookup(oh_name);
> > > > > +		if (!oh || oh->slaves_cnt == 0) {
> > > > > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> > > > >  			return -ENODEV;
> > > > > +		}
> > > > > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > > > > +	} else {
> > > > > +		return -ENODEV;
> > > > > +	}
> > > > 
> > > > How about have separate omap1 and omap2+ init functions that
> > > > call a common function and passes the pbase as a parameter?
> > > > 
> > > > That way we can get rid of the cpu_is_omapxxxx tests here.
> > > > 
> > > 
> > > Tony,
> > > 
> > > In the morning, I replied very soon, without much thinking...
> > > 
> > > Just now I started working on the patch, I was just reviewing the code, 
> > > and I felt that, it is unnecessary to split the code between omap1 and 
> > > omap2+.
> > > 
> > > The reason is,
> > > 
> > > Currently Only OMAP16xx base-address is hardcoded with
> > > cpu_is_omap16xx() macro, For all other omap family of devices the
> > > complete information is fetched from HWDMO api's/data.
> > 
> > In that case, why don't you create the platform_device by hand on
> > arch/arm/mach-omap1/devices.c and move the omap2+ (which is based on
> > hwmod) to arch/arm/mach-omap2/devices.c ?
> > 
> 
> Balbi,
> 
> 32k_counter code is not a platform_device/driver, we don't build the 
> any device here. We only need hwmod data to fetch the basic information like, 
> base-address, size, etc...
> 
> And I am note sure whether we really intend to make it 
> platform_device/driver thing.

that's kinda weird... anyway, you can also pass base as argument to
omap_init_clocksource_32k()... dunno.

-- 
balbi
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RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Mon, Mar 12, 2012 at 15:47:58, Balbi, Felipe wrote:
> Hi,
> 
> On Mon, Mar 12, 2012 at 09:48:20AM +0000, Hiremath, Vaibhav wrote:
> > On Mon, Mar 12, 2012 at 15:09:24, Balbi, Felipe wrote:
> > > On Fri, Mar 09, 2012 at 05:58:00PM +0000, Hiremath, Vaibhav wrote:
> > > > On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> > > > > Hi,
> > > > > 
> > > > > * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > > > > > OMAP device has 32k-sync timer which is currently used as a
> > > > > > clocksource in the kernel (omap2plus_defconfig).
> > > > > > The current implementation uses compile time selection between
> > > > > > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > > > > > the devices like AM33xx, where 32k-sync timer is not available.
> > > > > > 
> > > > > > So use hwmod database lookup mechanism, through which at run-time
> > > > > > we can identify availability of 32k-sync timer on the device,
> > > > > > else fall back to gp-timer.
> > > > > ...
> > > > > 
> > > > > > --- a/arch/arm/plat-omap/counter_32k.c
> > > > > > +++ b/arch/arm/plat-omap/counter_32k.c
> > > > > > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> > > > > >  
> > > > > >  int __init omap_init_clocksource_32k(void)
> > > > > >  {
> > > > > > -	static char err[] __initdata = KERN_ERR
> > > > > > -			"%s: can't register clocksource!\n";
> > > > > > -
> > > > > > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > > > > > -		u32 pbase;
> > > > > > -		unsigned long size = SZ_4K;
> > > > > > -		void __iomem *base;
> > > > > > -		struct clk *sync_32k_ick;
> > > > > > -
> > > > > > -		if (cpu_is_omap16xx()) {
> > > > > > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > > > -			size = SZ_1K;
> > > > > > -		} else if (cpu_is_omap2420())
> > > > > > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > > > > > -		else if (cpu_is_omap2430())
> > > > > > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > > > > > -		else if (cpu_is_omap34xx())
> > > > > > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > > > > > -		else if (cpu_is_omap44xx())
> > > > > > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > > > > > -		else
> > > > > > +	u32 pbase;
> > > > > > +	unsigned long size = SZ_4K;
> > > > > > +	void __iomem *base;
> > > > > > +	struct clk *sync_32k_ick;
> > > > > > +
> > > > > > +	if (cpu_is_omap16xx()) {
> > > > > > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > > > +		size = SZ_1K;
> > > > > > +	} else if (cpu_class_is_omap2()) {
> > > > > > +		struct omap_hwmod *oh;
> > > > > > +		const char *oh_name = "counter_32k";
> > > > > > +
> > > > > > +		oh = omap_hwmod_lookup(oh_name);
> > > > > > +		if (!oh || oh->slaves_cnt == 0) {
> > > > > > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> > > > > >  			return -ENODEV;
> > > > > > +		}
> > > > > > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > > > > > +	} else {
> > > > > > +		return -ENODEV;
> > > > > > +	}
> > > > > 
> > > > > How about have separate omap1 and omap2+ init functions that
> > > > > call a common function and passes the pbase as a parameter?
> > > > > 
> > > > > That way we can get rid of the cpu_is_omapxxxx tests here.
> > > > > 
> > > > 
> > > > Tony,
> > > > 
> > > > In the morning, I replied very soon, without much thinking...
> > > > 
> > > > Just now I started working on the patch, I was just reviewing the code, 
> > > > and I felt that, it is unnecessary to split the code between omap1 and 
> > > > omap2+.
> > > > 
> > > > The reason is,
> > > > 
> > > > Currently Only OMAP16xx base-address is hardcoded with
> > > > cpu_is_omap16xx() macro, For all other omap family of devices the
> > > > complete information is fetched from HWDMO api's/data.
> > > 
> > > In that case, why don't you create the platform_device by hand on
> > > arch/arm/mach-omap1/devices.c and move the omap2+ (which is based on
> > > hwmod) to arch/arm/mach-omap2/devices.c ?
> > > 
> > 
> > Balbi,
> > 
> > 32k_counter code is not a platform_device/driver, we don't build the 
> > any device here. We only need hwmod data to fetch the basic information like, 
> > base-address, size, etc...
> > 
> > And I am note sure whether we really intend to make it 
> > platform_device/driver thing.
> 
> that's kinda weird... 

Balbi,

Its not that weird, I think its because, this code is used as system 
clocksource.

> anyway, you can also pass base as argument to
> omap_init_clocksource_32k()... dunno.
> 

That's the whole point, just for one platform (omap16xx), we are changing the code. Rest all other platforms are using hwmod data, which is I believe 
is clean interface as of now.

To be more specific, we have to choose between something like -

"arch/arm/mach-omap1/timer32k.c"
bool __init omap_32k_timer_init(void) {
	omap_init_clocksource_32k(OMAP16XX_TIMER_32K_SYNCHRONIZED, SZ_1K);
	...
}
"arch/arm/mach-omap2/timer.c"

static void __init omap2_gp_clocksource_init(int gptimer_id,
                                                 const char *fck_source)
{
	/* Parse the hwmod data here*/
	Base = oh->slaves[0]->addr->pa_start + 0x10;
	Size = oh->slaves[0]->addr->pa_end - oh->slaves[0]->addr->pa_start;
	res = omap_init_clocksource_32k(base, size);
	if (!res)
		return;

	/* Fall back to gptimer */
}


OR

My current patch, which actually add cpu_is_16xx() check at one place and
does everything.


Thanks,
Vaibhav
> -- 
> balbi
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Mon, Mar 12, 2012 at 15:47:58, Balbi, Felipe wrote:
> Hi,
> 
> On Mon, Mar 12, 2012 at 09:48:20AM +0000, Hiremath, Vaibhav wrote:
> > On Mon, Mar 12, 2012 at 15:09:24, Balbi, Felipe wrote:
> > > On Fri, Mar 09, 2012 at 05:58:00PM +0000, Hiremath, Vaibhav wrote:
> > > > On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> > > > > Hi,
> > > > > 
> > > > > * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > > > > > OMAP device has 32k-sync timer which is currently used as a
> > > > > > clocksource in the kernel (omap2plus_defconfig).
> > > > > > The current implementation uses compile time selection between
> > > > > > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > > > > > the devices like AM33xx, where 32k-sync timer is not available.
> > > > > > 
> > > > > > So use hwmod database lookup mechanism, through which at run-time
> > > > > > we can identify availability of 32k-sync timer on the device,
> > > > > > else fall back to gp-timer.
> > > > > ...
> > > > > 
> > > > > > --- a/arch/arm/plat-omap/counter_32k.c
> > > > > > +++ b/arch/arm/plat-omap/counter_32k.c
> > > > > > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> > > > > >  
> > > > > >  int __init omap_init_clocksource_32k(void)
> > > > > >  {
> > > > > > -	static char err[] __initdata = KERN_ERR
> > > > > > -			"%s: can't register clocksource!\n";
> > > > > > -
> > > > > > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > > > > > -		u32 pbase;
> > > > > > -		unsigned long size = SZ_4K;
> > > > > > -		void __iomem *base;
> > > > > > -		struct clk *sync_32k_ick;
> > > > > > -
> > > > > > -		if (cpu_is_omap16xx()) {
> > > > > > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > > > -			size = SZ_1K;
> > > > > > -		} else if (cpu_is_omap2420())
> > > > > > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > > > > > -		else if (cpu_is_omap2430())
> > > > > > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > > > > > -		else if (cpu_is_omap34xx())
> > > > > > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > > > > > -		else if (cpu_is_omap44xx())
> > > > > > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > > > > > -		else
> > > > > > +	u32 pbase;
> > > > > > +	unsigned long size = SZ_4K;
> > > > > > +	void __iomem *base;
> > > > > > +	struct clk *sync_32k_ick;
> > > > > > +
> > > > > > +	if (cpu_is_omap16xx()) {
> > > > > > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > > > > > +		size = SZ_1K;
> > > > > > +	} else if (cpu_class_is_omap2()) {
> > > > > > +		struct omap_hwmod *oh;
> > > > > > +		const char *oh_name = "counter_32k";
> > > > > > +
> > > > > > +		oh = omap_hwmod_lookup(oh_name);
> > > > > > +		if (!oh || oh->slaves_cnt == 0) {
> > > > > > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> > > > > >  			return -ENODEV;
> > > > > > +		}
> > > > > > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > > > > > +	} else {
> > > > > > +		return -ENODEV;
> > > > > > +	}
> > > > > 
> > > > > How about have separate omap1 and omap2+ init functions that
> > > > > call a common function and passes the pbase as a parameter?
> > > > > 
> > > > > That way we can get rid of the cpu_is_omapxxxx tests here.
> > > > > 
> > > > 
> > > > Tony,
> > > > 
> > > > In the morning, I replied very soon, without much thinking...
> > > > 
> > > > Just now I started working on the patch, I was just reviewing the code, 
> > > > and I felt that, it is unnecessary to split the code between omap1 and 
> > > > omap2+.
> > > > 
> > > > The reason is,
> > > > 
> > > > Currently Only OMAP16xx base-address is hardcoded with
> > > > cpu_is_omap16xx() macro, For all other omap family of devices the
> > > > complete information is fetched from HWDMO api's/data.
> > > 
> > > In that case, why don't you create the platform_device by hand on
> > > arch/arm/mach-omap1/devices.c and move the omap2+ (which is based on
> > > hwmod) to arch/arm/mach-omap2/devices.c ?
> > > 
> > 
> > Balbi,
> > 
> > 32k_counter code is not a platform_device/driver, we don't build the 
> > any device here. We only need hwmod data to fetch the basic information like, 
> > base-address, size, etc...
> > 
> > And I am note sure whether we really intend to make it 
> > platform_device/driver thing.
> 
> that's kinda weird... 

Balbi,

Its not that weird, I think its because, this code is used as system 
clocksource.

> anyway, you can also pass base as argument to
> omap_init_clocksource_32k()... dunno.
> 

That's the whole point, just for one platform (omap16xx), we are changing the code. Rest all other platforms are using hwmod data, which is I believe 
is clean interface as of now.

To be more specific, we have to choose between something like -

"arch/arm/mach-omap1/timer32k.c"
bool __init omap_32k_timer_init(void) {
	omap_init_clocksource_32k(OMAP16XX_TIMER_32K_SYNCHRONIZED, SZ_1K);
	...
}
"arch/arm/mach-omap2/timer.c"

static void __init omap2_gp_clocksource_init(int gptimer_id,
                                                 const char *fck_source)
{
	/* Parse the hwmod data here*/
	Base = oh->slaves[0]->addr->pa_start + 0x10;
	Size = oh->slaves[0]->addr->pa_end - oh->slaves[0]->addr->pa_start;
	res = omap_init_clocksource_32k(base, size);
	if (!res)
		return;

	/* Fall back to gptimer */
}


OR

My current patch, which actually add cpu_is_16xx() check at one place and
does everything.


Thanks,
Vaibhav
> -- 
> balbi
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

Hi,

On Tue, Jan 24, 2012 at 7:38 AM, Kevin Hilman <khilman@ti.com> wrote:
> Vaibhav Hiremath <hvaibhav@ti.com> writes:
>
>> OMAP device has 32k-sync timer which is currently used as a
>> clocksource in the kernel (omap2plus_defconfig).
>> The current implementation uses compile time selection between
>> gp-timer and 32k-sync timer, which breaks multi-omap build for
>> the devices like AM33xx, where 32k-sync timer is not available.
>>
>> So use hwmod database lookup mechanism, through which at run-time
>> we can identify availability of 32k-sync timer on the device,
>> else fall back to gp-timer.
>
> With the runtime detection & fallback, I suggest also removing the
> Kconfig choice between the two as well.

IMO, under some situations, gp timer clocksource has high precision
and is very useful, so hope the Kconfig choice can be kept, or using
kernel parameter way,  and the patch need to be changed to support the
selection.


thanks,
-- 
Ming Lei

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

Hi,

On Tue, Jan 24, 2012 at 7:38 AM, Kevin Hilman <khilman@ti.com> wrote:
> Vaibhav Hiremath <hvaibhav@ti.com> writes:
>
>> OMAP device has 32k-sync timer which is currently used as a
>> clocksource in the kernel (omap2plus_defconfig).
>> The current implementation uses compile time selection between
>> gp-timer and 32k-sync timer, which breaks multi-omap build for
>> the devices like AM33xx, where 32k-sync timer is not available.
>>
>> So use hwmod database lookup mechanism, through which at run-time
>> we can identify availability of 32k-sync timer on the device,
>> else fall back to gp-timer.
>
> With the runtime detection & fallback, I suggest also removing the
> Kconfig choice between the two as well.

IMO, under some situations, gp timer clocksource has high precision
and is very useful, so hope the Kconfig choice can be kept, or using
kernel parameter way,  and the patch need to be changed to support the
selection.


thanks,
-- 
Ming Lei

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Mar 13, 2012 at 17:07:16, Ming Lei wrote:
> Hi,
> 
> On Tue, Jan 24, 2012 at 7:38 AM, Kevin Hilman <khilman@ti.com> wrote:
> > Vaibhav Hiremath <hvaibhav@ti.com> writes:
> >
> >> OMAP device has 32k-sync timer which is currently used as a
> >> clocksource in the kernel (omap2plus_defconfig).
> >> The current implementation uses compile time selection between
> >> gp-timer and 32k-sync timer, which breaks multi-omap build for
> >> the devices like AM33xx, where 32k-sync timer is not available.
> >>
> >> So use hwmod database lookup mechanism, through which at run-time
> >> we can identify availability of 32k-sync timer on the device,
> >> else fall back to gp-timer.
> >
> > With the runtime detection & fallback, I suggest also removing the
> > Kconfig choice between the two as well.
> 
> IMO, under some situations, gp timer clocksource has high precision
> and is very useful, so hope the Kconfig choice can be kept, or using
> kernel parameter way,  and the patch need to be changed to support the
> selection.
> 
> 

I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
It will always use 32k-counter, and never fall back to dmtimer.

Then the only options we have here is,

1) Register both the timers, 32k-counter and dmtimer for clocksource; let
   Kernel pick up best rating clocksource out of these two.

   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better 
   Rating. User can choose the 32k-counter clocksource via bootargs.

   Impact: without bootargs for clocksource selection, kernel will choose 
     dmtimer, impacting loss of time during suspend/resume.


2) Let the current code be as is, means, the clocksource registration will 
   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option 
   selection will be Controlled by Kconfig rules.


Based on this conclusion, 1st patch of this series needs some changes.
But Irrespective of this, we still need 2 patches from this series,

[PATCH 2/3] ARM: OMAP2+: hwmod data: Add 32k-sync timer data to hwmod database
[PATCH 3/3] ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common header


Thanks,
Vaibhav

> thanks,
> -- 
> Ming Lei
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Mar 13, 2012 at 17:07:16, Ming Lei wrote:
> Hi,
> 
> On Tue, Jan 24, 2012 at 7:38 AM, Kevin Hilman <khilman@ti.com> wrote:
> > Vaibhav Hiremath <hvaibhav@ti.com> writes:
> >
> >> OMAP device has 32k-sync timer which is currently used as a
> >> clocksource in the kernel (omap2plus_defconfig).
> >> The current implementation uses compile time selection between
> >> gp-timer and 32k-sync timer, which breaks multi-omap build for
> >> the devices like AM33xx, where 32k-sync timer is not available.
> >>
> >> So use hwmod database lookup mechanism, through which at run-time
> >> we can identify availability of 32k-sync timer on the device,
> >> else fall back to gp-timer.
> >
> > With the runtime detection & fallback, I suggest also removing the
> > Kconfig choice between the two as well.
> 
> IMO, under some situations, gp timer clocksource has high precision
> and is very useful, so hope the Kconfig choice can be kept, or using
> kernel parameter way,  and the patch need to be changed to support the
> selection.
> 
> 

I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
It will always use 32k-counter, and never fall back to dmtimer.

Then the only options we have here is,

1) Register both the timers, 32k-counter and dmtimer for clocksource; let
   Kernel pick up best rating clocksource out of these two.

   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better 
   Rating. User can choose the 32k-counter clocksource via bootargs.

   Impact: without bootargs for clocksource selection, kernel will choose 
     dmtimer, impacting loss of time during suspend/resume.


2) Let the current code be as is, means, the clocksource registration will 
   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option 
   selection will be Controlled by Kconfig rules.


Based on this conclusion, 1st patch of this series needs some changes.
But Irrespective of this, we still need 2 patches from this series,

[PATCH 2/3] ARM: OMAP2+: hwmod data: Add 32k-sync timer data to hwmod database
[PATCH 3/3] ARM: OMAP2/3: Add idle_st bits for ST_32KSYNC timer to prcm-common header


Thanks,
Vaibhav

> thanks,
> -- 
> Ming Lei
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>
> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> It will always use 32k-counter, and never fall back to dmtimer.
>
> Then the only options we have here is,
>
> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
>   Kernel pick up best rating clocksource out of these two.
>
>   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
>   Rating. User can choose the 32k-counter clocksource via bootargs.
>
>   Impact: without bootargs for clocksource selection, kernel will choose
>     dmtimer, impacting loss of time during suspend/resume.
>
>
> 2) Let the current code be as is, means, the clocksource registration will
>   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
>   selection will be Controlled by Kconfig rules.

How about the 3rd option?

3), take the way in your patch 1) at default, but will switch to
register dmtimer
directly and bypass 32k-counter if user need it via kernel parameter.

As far as I can think of, the situations required for dmtimer are high-frequency
perf sample and high precision trace points, so looks it is OK to take
32k-counter
at default.

Thanks,
-- 
Ming Lei
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>
> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> It will always use 32k-counter, and never fall back to dmtimer.
>
> Then the only options we have here is,
>
> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
> ? Kernel pick up best rating clocksource out of these two.
>
> ? In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
> ? Rating. User can choose the 32k-counter clocksource via bootargs.
>
> ? Impact: without bootargs for clocksource selection, kernel will choose
> ? ? dmtimer, impacting loss of time during suspend/resume.
>
>
> 2) Let the current code be as is, means, the clocksource registration will
> ? Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
> ? selection will be Controlled by Kconfig rules.

How about the 3rd option?

3), take the way in your patch 1) at default, but will switch to
register dmtimer
directly and bypass 32k-counter if user need it via kernel parameter.

As far as I can think of, the situations required for dmtimer are high-frequency
perf sample and high precision trace points, so looks it is OK to take
32k-counter
at default.

Thanks,
-- 
Ming Lei

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>
>> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
>> It will always use 32k-counter, and never fall back to dmtimer.
>>
>> Then the only options we have here is,
>>
>> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
>>   Kernel pick up best rating clocksource out of these two.
>>
>>   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
>>   Rating. User can choose the 32k-counter clocksource via bootargs.
>>
>>   Impact: without bootargs for clocksource selection, kernel will choose
>>     dmtimer, impacting loss of time during suspend/resume.
>>
This is the right option. The problem is gptimer clocksource
doesn't work across power transitions and hence it is broken.

Even for the perf, with PM enabled, dmtimer can't be used or it needs
to be used with 32KHz clock which makes it no better than sync timer.

So here keeping 32K sync timer is default clocksource makes sense since
it is the only working and viable option.

So what can be done is register both 32K and gptimer together but make
gptimer clocksource registration depends on PM enabled.

This should solve all the needs I guess.

>>
>> 2) Let the current code be as is, means, the clocksource registration will
>>   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
>>   selection will be Controlled by Kconfig rules.
> 
We should get rid off CONFIG_OMAP_32K_TIMER.

Regards
Santosh

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>
>> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
>> It will always use 32k-counter, and never fall back to dmtimer.
>>
>> Then the only options we have here is,
>>
>> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
>>   Kernel pick up best rating clocksource out of these two.
>>
>>   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
>>   Rating. User can choose the 32k-counter clocksource via bootargs.
>>
>>   Impact: without bootargs for clocksource selection, kernel will choose
>>     dmtimer, impacting loss of time during suspend/resume.
>>
This is the right option. The problem is gptimer clocksource
doesn't work across power transitions and hence it is broken.

Even for the perf, with PM enabled, dmtimer can't be used or it needs
to be used with 32KHz clock which makes it no better than sync timer.

So here keeping 32K sync timer is default clocksource makes sense since
it is the only working and viable option.

So what can be done is register both 32K and gptimer together but make
gptimer clocksource registration depends on PM enabled.

This should solve all the needs I guess.

>>
>> 2) Let the current code be as is, means, the clocksource registration will
>>   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
>>   selection will be Controlled by Kconfig rules.
> 
We should get rid off CONFIG_OMAP_32K_TIMER.

Regards
Santosh

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Mon, Mar 19, 2012 at 17:14:30, Ming Lei wrote:
> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >
> > I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> > It will always use 32k-counter, and never fall back to dmtimer.
> >
> > Then the only options we have here is,
> >
> > 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
> >   Kernel pick up best rating clocksource out of these two.
> >
> >   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
> >   Rating. User can choose the 32k-counter clocksource via bootargs.
> >
> >   Impact: without bootargs for clocksource selection, kernel will choose
> >     dmtimer, impacting loss of time during suspend/resume.
> >
> >
> > 2) Let the current code be as is, means, the clocksource registration will
> >   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
> >   selection will be Controlled by Kconfig rules.
> 
> How about the 3rd option?
> 
> 3), take the way in your patch 1) at default, but will switch to
> register dmtimer
> directly and bypass 32k-counter if user need it via kernel parameter.
> 
> As far as I can think of, the situations required for dmtimer are high-frequency
> perf sample and high precision trace points, so looks it is OK to take
> 32k-counter
> at default.
> 
But if you register both the timers (dmtimer & 32ksync), then initially kernel will only pick up dmtimer, as this has better rating. And late in
the boot sequence clocksource switch will happen, base on 
kernel parameter (clocksource=).

So logically dmtimer will be always used as a default here.

Thanks,
Vaibhav

> Thanks,
> -- 
> Ming Lei
> 

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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Mon, Mar 19, 2012 at 17:14:30, Ming Lei wrote:
> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >
> > I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> > It will always use 32k-counter, and never fall back to dmtimer.
> >
> > Then the only options we have here is,
> >
> > 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
> > ? Kernel pick up best rating clocksource out of these two.
> >
> > ? In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
> > ? Rating. User can choose the 32k-counter clocksource via bootargs.
> >
> > ? Impact: without bootargs for clocksource selection, kernel will choose
> > ? ? dmtimer, impacting loss of time during suspend/resume.
> >
> >
> > 2) Let the current code be as is, means, the clocksource registration will
> > ? Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
> > ? selection will be Controlled by Kconfig rules.
> 
> How about the 3rd option?
> 
> 3), take the way in your patch 1) at default, but will switch to
> register dmtimer
> directly and bypass 32k-counter if user need it via kernel parameter.
> 
> As far as I can think of, the situations required for dmtimer are high-frequency
> perf sample and high precision trace points, so looks it is OK to take
> 32k-counter
> at default.
> 
But if you register both the timers (dmtimer & 32ksync), then initially kernel will only pick up dmtimer, as this has better rating. And late in
the boot sequence clocksource switch will happen, base on 
kernel parameter (clocksource=).

So logically dmtimer will be always used as a default here.

Thanks,
Vaibhav

> Thanks,
> -- 
> Ming Lei
> 

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>
> >> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> >> It will always use 32k-counter, and never fall back to dmtimer.
> >>
> >> Then the only options we have here is,
> >>
> >> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
> >>   Kernel pick up best rating clocksource out of these two.
> >>
> >>   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
> >>   Rating. User can choose the 32k-counter clocksource via bootargs.
> >>
> >>   Impact: without bootargs for clocksource selection, kernel will choose
> >>     dmtimer, impacting loss of time during suspend/resume.
> >>
> This is the right option. The problem is gptimer clocksource
> doesn't work across power transitions and hence it is broken.
> 
> Even for the perf, with PM enabled, dmtimer can't be used or it needs
> to be used with 32KHz clock which makes it no better than sync timer.
> 
> So here keeping 32K sync timer is default clocksource makes sense since
> it is the only working and viable option.
> 
> So what can be done is register both 32K and gptimer together but make
> gptimer clocksource registration depends on PM enabled.
> 
> This should solve all the needs I guess.
> 

I am not sure this will work on all platforms, for example, AM33XX, where
We do not have 32ksync timer available, but we need PM support. Also, I 
personally think, we should not again use compile time option here.

So the only option I have here is, register both the clocksources, let dmtimer be a default clocksource for the kernel (since it has better rating),
And based on kernel parameter user can change the clocksource, specially 
for PM use-cases.


Implementation point of view, I just need to do something like,

static void __init omap2_gp_clocksource_init(int gptimer_id,
							const char *fck_source)
{
	int res;

	res = omap_init_clocksource_32k();
	if (!res)
		pr_err("failed to register 32ksync counter as a clocksource\n");

	/* 
	 * Continue with dmtimer registration as well, irrespective of
	 * whether 32ksync timer registration succeeded or not.
	 */
}

> >>
> >> 2) Let the current code be as is, means, the clocksource registration will
> >>   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
> >>   selection will be Controlled by Kconfig rules.
> > 
> We should get rid off CONFIG_OMAP_32K_TIMER.
> 

Agreed, I will take this activity once I close on this.

Thanks,
Vaibhav

> Regards
> Santosh
> 
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>
> >> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> >> It will always use 32k-counter, and never fall back to dmtimer.
> >>
> >> Then the only options we have here is,
> >>
> >> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
> >>   Kernel pick up best rating clocksource out of these two.
> >>
> >>   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
> >>   Rating. User can choose the 32k-counter clocksource via bootargs.
> >>
> >>   Impact: without bootargs for clocksource selection, kernel will choose
> >>     dmtimer, impacting loss of time during suspend/resume.
> >>
> This is the right option. The problem is gptimer clocksource
> doesn't work across power transitions and hence it is broken.
> 
> Even for the perf, with PM enabled, dmtimer can't be used or it needs
> to be used with 32KHz clock which makes it no better than sync timer.
> 
> So here keeping 32K sync timer is default clocksource makes sense since
> it is the only working and viable option.
> 
> So what can be done is register both 32K and gptimer together but make
> gptimer clocksource registration depends on PM enabled.
> 
> This should solve all the needs I guess.
> 

I am not sure this will work on all platforms, for example, AM33XX, where
We do not have 32ksync timer available, but we need PM support. Also, I 
personally think, we should not again use compile time option here.

So the only option I have here is, register both the clocksources, let dmtimer be a default clocksource for the kernel (since it has better rating),
And based on kernel parameter user can change the clocksource, specially 
for PM use-cases.


Implementation point of view, I just need to do something like,

static void __init omap2_gp_clocksource_init(int gptimer_id,
							const char *fck_source)
{
	int res;

	res = omap_init_clocksource_32k();
	if (!res)
		pr_err("failed to register 32ksync counter as a clocksource\n");

	/* 
	 * Continue with dmtimer registration as well, irrespective of
	 * whether 32ksync timer registration succeeded or not.
	 */
}

> >>
> >> 2) Let the current code be as is, means, the clocksource registration will
> >>   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
> >>   selection will be Controlled by Kconfig rules.
> > 
> We should get rid off CONFIG_OMAP_32K_TIMER.
> 

Agreed, I will take this activity once I close on this.

Thanks,
Vaibhav

> Regards
> Santosh
> 
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >>
>> >> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
>> >> It will always use 32k-counter, and never fall back to dmtimer.
>> >>
>> >> Then the only options we have here is,
>> >>
>> >> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
>> >>   Kernel pick up best rating clocksource out of these two.
>> >>
>> >>   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
>> >>   Rating. User can choose the 32k-counter clocksource via bootargs.
>> >>
>> >>   Impact: without bootargs for clocksource selection, kernel will choose
>> >>     dmtimer, impacting loss of time during suspend/resume.
>> >>
>> This is the right option. The problem is gptimer clocksource
>> doesn't work across power transitions and hence it is broken.
>>
>> Even for the perf, with PM enabled, dmtimer can't be used or it needs
>> to be used with 32KHz clock which makes it no better than sync timer.
>>
>> So here keeping 32K sync timer is default clocksource makes sense since
>> it is the only working and viable option.
>>
>> So what can be done is register both 32K and gptimer together but make
>> gptimer clocksource registration depends on PM enabled.
>>
>> This should solve all the needs I guess.
>>
>
> I am not sure this will work on all platforms, for example, AM33XX, where
> We do not have 32ksync timer available, but we need PM support. Also, I
> personally think, we should not again use compile time option here.
>
Why not ?
If 32ksync timer is not available, don't register it. Then in AM case
you just have one clock-source. I am against the idea of making
gptimer as the default and asking user to choose sync32k from
command-line.

Btw, if you need PM, how are you going to use GPTIMER
as a clocksource. Note sys-clock is generally stopped in
low power states. So that leaves you option with using
gptimer with 32K clock and in that case, GPTIMER
is not a better clock-source compare to 32K sync timer
and so shouldn't be the rating.

Regards
Santosh
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >>
>> >> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
>> >> It will always use 32k-counter, and never fall back to dmtimer.
>> >>
>> >> Then the only options we have here is,
>> >>
>> >> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
>> >> ? Kernel pick up best rating clocksource out of these two.
>> >>
>> >> ? In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
>> >> ? Rating. User can choose the 32k-counter clocksource via bootargs.
>> >>
>> >> ? Impact: without bootargs for clocksource selection, kernel will choose
>> >> ? ? dmtimer, impacting loss of time during suspend/resume.
>> >>
>> This is the right option. The problem is gptimer clocksource
>> doesn't work across power transitions and hence it is broken.
>>
>> Even for the perf, with PM enabled, dmtimer can't be used or it needs
>> to be used with 32KHz clock which makes it no better than sync timer.
>>
>> So here keeping 32K sync timer is default clocksource makes sense since
>> it is the only working and viable option.
>>
>> So what can be done is register both 32K and gptimer together but make
>> gptimer clocksource registration depends on PM enabled.
>>
>> This should solve all the needs I guess.
>>
>
> I am not sure this will work on all platforms, for example, AM33XX, where
> We do not have 32ksync timer available, but we need PM support. Also, I
> personally think, we should not again use compile time option here.
>
Why not ?
If 32ksync timer is not available, don't register it. Then in AM case
you just have one clock-source. I am against the idea of making
gptimer as the default and asking user to choose sync32k from
command-line.

Btw, if you need PM, how are you going to use GPTIMER
as a clocksource. Note sys-clock is generally stopped in
low power states. So that leaves you option with using
gptimer with 32K clock and in that case, GPTIMER
is not a better clock-source compare to 32K sync timer
and so shouldn't be the rating.

Regards
Santosh

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Wed, Mar 21, 2012 at 7:29 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Mon, Mar 19, 2012 at 17:14:30, Ming Lei wrote:
>> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >
>> > I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
>> > It will always use 32k-counter, and never fall back to dmtimer.
>> >
>> > Then the only options we have here is,
>> >
>> > 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
>> >   Kernel pick up best rating clocksource out of these two.
>> >
>> >   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
>> >   Rating. User can choose the 32k-counter clocksource via bootargs.
>> >
>> >   Impact: without bootargs for clocksource selection, kernel will choose
>> >     dmtimer, impacting loss of time during suspend/resume.
>> >
>> >
>> > 2) Let the current code be as is, means, the clocksource registration will
>> >   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
>> >   selection will be Controlled by Kconfig rules.
>>
>> How about the 3rd option?
>>
>> 3), take the way in your patch 1) at default, but will switch to
>> register dmtimer
>> directly and bypass 32k-counter if user need it via kernel parameter.
>>
>> As far as I can think of, the situations required for dmtimer are high-frequency
>> perf sample and high precision trace points, so looks it is OK to take
>> 32k-counter
>> at default.
>>
> But if you register both the timers (dmtimer & 32ksync), then initially kernel will only pick up dmtimer, as this has better rating. And late in

Looks not so, I found that 32ksync is always selected as the default
clocksource if both are registered.

> the boot sequence clocksource switch will happen, base on
> kernel parameter (clocksource=).
>
> So logically dmtimer will be always used as a default here.

Not so at least on my Pandaboard.


Thanks,
-- 
Ming Lei
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Wed, Mar 21, 2012 at 7:29 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Mon, Mar 19, 2012 at 17:14:30, Ming Lei wrote:
>> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >
>> > I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
>> > It will always use 32k-counter, and never fall back to dmtimer.
>> >
>> > Then the only options we have here is,
>> >
>> > 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
>> > ? Kernel pick up best rating clocksource out of these two.
>> >
>> > ? In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
>> > ? Rating. User can choose the 32k-counter clocksource via bootargs.
>> >
>> > ? Impact: without bootargs for clocksource selection, kernel will choose
>> > ? ? dmtimer, impacting loss of time during suspend/resume.
>> >
>> >
>> > 2) Let the current code be as is, means, the clocksource registration will
>> > ? Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
>> > ? selection will be Controlled by Kconfig rules.
>>
>> How about the 3rd option?
>>
>> 3), take the way in your patch 1) at default, but will switch to
>> register dmtimer
>> directly and bypass 32k-counter if user need it via kernel parameter.
>>
>> As far as I can think of, the situations required for dmtimer are high-frequency
>> perf sample and high precision trace points, so looks it is OK to take
>> 32k-counter
>> at default.
>>
> But if you register both the timers (dmtimer & 32ksync), then initially kernel will only pick up dmtimer, as this has better rating. And late in

Looks not so, I found that 32ksync is always selected as the default
clocksource if both are registered.

> the boot sequence clocksource switch will happen, base on
> kernel parameter (clocksource=).
>
> So logically dmtimer will be always used as a default here.

Not so at least on my Pandaboard.


Thanks,
-- 
Ming Lei

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >>
> >> >> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> >> >> It will always use 32k-counter, and never fall back to dmtimer.
> >> >>
> >> >> Then the only options we have here is,
> >> >>
> >> >> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
> >> >>   Kernel pick up best rating clocksource out of these two.
> >> >>
> >> >>   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
> >> >>   Rating. User can choose the 32k-counter clocksource via bootargs.
> >> >>
> >> >>   Impact: without bootargs for clocksource selection, kernel will choose
> >> >>     dmtimer, impacting loss of time during suspend/resume.
> >> >>
> >> This is the right option. The problem is gptimer clocksource
> >> doesn't work across power transitions and hence it is broken.
> >>
> >> Even for the perf, with PM enabled, dmtimer can't be used or it needs
> >> to be used with 32KHz clock which makes it no better than sync timer.
> >>
> >> So here keeping 32K sync timer is default clocksource makes sense since
> >> it is the only working and viable option.
> >>
> >> So what can be done is register both 32K and gptimer together but make
> >> gptimer clocksource registration depends on PM enabled.
> >>
> >> This should solve all the needs I guess.
> >>
> >
> > I am not sure this will work on all platforms, for example, AM33XX, where
> > We do not have 32ksync timer available, but we need PM support. Also, I
> > personally think, we should not again use compile time option here.
> >
> Why not ?
> If 32ksync timer is not available, don't register it. Then in AM case
> you just have one clock-source. 

In case of AM33xx, what about kernel without PM support?
As clocksource registration would be dependent on PM option, it won't work.

> I am against the idea of making
> gptimer as the default and asking user to choose sync32k from
> command-line.
> 

I understand your concern here.


> Btw, if you need PM, how are you going to use GPTIMER
> as a clocksource. Note sys-clock is generally stopped in
> low power states. So that leaves you option with using
> gptimer with 32K clock and in that case, GPTIMER
> is not a better clock-source compare to 32K sync timer
> and so shouldn't be the rating.
> 

AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
Clocksource, without any issues.

Thanks,
Vaibhav

> Regards
> Santosh
> 

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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >>
> >> >> I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> >> >> It will always use 32k-counter, and never fall back to dmtimer.
> >> >>
> >> >> Then the only options we have here is,
> >> >>
> >> >> 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
> >> >> ? Kernel pick up best rating clocksource out of these two.
> >> >>
> >> >> ? In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
> >> >> ? Rating. User can choose the 32k-counter clocksource via bootargs.
> >> >>
> >> >> ? Impact: without bootargs for clocksource selection, kernel will choose
> >> >> ? ? dmtimer, impacting loss of time during suspend/resume.
> >> >>
> >> This is the right option. The problem is gptimer clocksource
> >> doesn't work across power transitions and hence it is broken.
> >>
> >> Even for the perf, with PM enabled, dmtimer can't be used or it needs
> >> to be used with 32KHz clock which makes it no better than sync timer.
> >>
> >> So here keeping 32K sync timer is default clocksource makes sense since
> >> it is the only working and viable option.
> >>
> >> So what can be done is register both 32K and gptimer together but make
> >> gptimer clocksource registration depends on PM enabled.
> >>
> >> This should solve all the needs I guess.
> >>
> >
> > I am not sure this will work on all platforms, for example, AM33XX, where
> > We do not have 32ksync timer available, but we need PM support. Also, I
> > personally think, we should not again use compile time option here.
> >
> Why not ?
> If 32ksync timer is not available, don't register it. Then in AM case
> you just have one clock-source. 

In case of AM33xx, what about kernel without PM support?
As clocksource registration would be dependent on PM option, it won't work.

> I am against the idea of making
> gptimer as the default and asking user to choose sync32k from
> command-line.
> 

I understand your concern here.


> Btw, if you need PM, how are you going to use GPTIMER
> as a clocksource. Note sys-clock is generally stopped in
> low power states. So that leaves you option with using
> gptimer with 32K clock and in that case, GPTIMER
> is not a better clock-source compare to 32K sync timer
> and so shouldn't be the rating.
> 

AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
Clocksource, without any issues.

Thanks,
Vaibhav

> Regards
> Santosh
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
>> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:

[...]

>
>> Btw, if you need PM, how are you going to use GPTIMER
>> as a clocksource. Note sys-clock is generally stopped in
>> low power states. So that leaves you option with using
>> gptimer with 32K clock and in that case, GPTIMER
>> is not a better clock-source compare to 32K sync timer
>> and so shouldn't be the rating.
>>
>
> AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
> Clocksource, without any issues.
>
GPTIMER1 is in wakeup domain on OMAP too but that doesn't
solve the issue I am talking. Once the sysclock is stopped, GPTIMER
can't tick anymore even if it is in wakeup domain.

The only way it will work is using always running 32KHz clock as
the clock input to GPT1. And then the end result is the accuracy
of GPTIMER = sync 32K timer. So they are of same rating.

Hope it is clear now.

Regards
Santosh

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
>> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:

[...]

>
>> Btw, if you need PM, how are you going to use GPTIMER
>> as a clocksource. Note sys-clock is generally stopped in
>> low power states. So that leaves you option with using
>> gptimer with 32K clock and in that case, GPTIMER
>> is not a better clock-source compare to 32K sync timer
>> and so shouldn't be the rating.
>>
>
> AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
> Clocksource, without any issues.
>
GPTIMER1 is in wakeup domain on OMAP too but that doesn't
solve the issue I am talking. Once the sysclock is stopped, GPTIMER
can't tick anymore even if it is in wakeup domain.

The only way it will work is using always running 32KHz clock as
the clock input to GPT1. And then the end result is the accuracy
of GPTIMER = sync 32K timer. So they are of same rating.

Hope it is clear now.

Regards
Santosh

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> 
> [...]
> 
> >
> >> Btw, if you need PM, how are you going to use GPTIMER
> >> as a clocksource. Note sys-clock is generally stopped in
> >> low power states. So that leaves you option with using
> >> gptimer with 32K clock and in that case, GPTIMER
> >> is not a better clock-source compare to 32K sync timer
> >> and so shouldn't be the rating.
> >>
> >
> > AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
> > Clocksource, without any issues.
> >
> GPTIMER1 is in wakeup domain on OMAP too but that doesn't
> solve the issue I am talking. Once the sysclock is stopped, GPTIMER
> can't tick anymore even if it is in wakeup domain.
> 
> The only way it will work is using always running 32KHz clock as
> the clock input to GPT1. And then the end result is the accuracy
> of GPTIMER = sync 32K timer. So they are of same rating.
> 

Ohh ok, sorry I should have clarified it in my last response itself.

AM33xx architecture is bit different than OMAP family, and gmtimer1 is 
sourced from RTC32K clock, which is in wakeup domain.
This means we have RTC32K clock always running across suspend/resume.

0 - SEL1: Select CLK_M_OSC clock
1 - SEL2: Select CLK_32KHZ clock
2 - SEL3: Select TCLKIN clock
3 - SEL4: Select CLK_RC32K clock
4 - SEL5: Selects the CLK_32768 from 32KHz Crystal Osc


We use value "4" here, for RTC32K (always on clock).
I hope this clarifies what I am trying to say here.


Thanks,
Vaibhav

> Hope it is clear now.
> 
> Regards
> Santosh
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> 
> [...]
> 
> >
> >> Btw, if you need PM, how are you going to use GPTIMER
> >> as a clocksource. Note sys-clock is generally stopped in
> >> low power states. So that leaves you option with using
> >> gptimer with 32K clock and in that case, GPTIMER
> >> is not a better clock-source compare to 32K sync timer
> >> and so shouldn't be the rating.
> >>
> >
> > AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
> > Clocksource, without any issues.
> >
> GPTIMER1 is in wakeup domain on OMAP too but that doesn't
> solve the issue I am talking. Once the sysclock is stopped, GPTIMER
> can't tick anymore even if it is in wakeup domain.
> 
> The only way it will work is using always running 32KHz clock as
> the clock input to GPT1. And then the end result is the accuracy
> of GPTIMER = sync 32K timer. So they are of same rating.
> 

Ohh ok, sorry I should have clarified it in my last response itself.

AM33xx architecture is bit different than OMAP family, and gmtimer1 is 
sourced from RTC32K clock, which is in wakeup domain.
This means we have RTC32K clock always running across suspend/resume.

0 - SEL1: Select CLK_M_OSC clock
1 - SEL2: Select CLK_32KHZ clock
2 - SEL3: Select TCLKIN clock
3 - SEL4: Select CLK_RC32K clock
4 - SEL5: Selects the CLK_32768 from 32KHz Crystal Osc


We use value "4" here, for RTC32K (always on clock).
I hope this clarifies what I am trying to say here.


Thanks,
Vaibhav

> Hope it is clear now.
> 
> Regards
> Santosh
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
>> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
>> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>
>> [...]
>>
>> >
>> >> Btw, if you need PM, how are you going to use GPTIMER
>> >> as a clocksource. Note sys-clock is generally stopped in
>> >> low power states. So that leaves you option with using
>> >> gptimer with 32K clock and in that case, GPTIMER
>> >> is not a better clock-source compare to 32K sync timer
>> >> and so shouldn't be the rating.
>> >>
>> >
>> > AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
>> > Clocksource, without any issues.
>> >
>> GPTIMER1 is in wakeup domain on OMAP too but that doesn't
>> solve the issue I am talking. Once the sysclock is stopped, GPTIMER
>> can't tick anymore even if it is in wakeup domain.
>>
>> The only way it will work is using always running 32KHz clock as
>> the clock input to GPT1. And then the end result is the accuracy
>> of GPTIMER = sync 32K timer. So they are of same rating.
>>
>
> Ohh ok, sorry I should have clarified it in my last response itself.
>
np.

> AM33xx architecture is bit different than OMAP family, and gmtimer1 is
> sourced from RTC32K clock, which is in wakeup domain.
> This means we have RTC32K clock always running across suspend/resume.
>
> 0 - SEL1: Select CLK_M_OSC clock
> 1 - SEL2: Select CLK_32KHZ clock
> 2 - SEL3: Select TCLKIN clock
> 3 - SEL4: Select CLK_RC32K clock
> 4 - SEL5: Selects the CLK_32768 from 32KHz Crystal Osc
>
>
> We use value "4" here, for RTC32K (always on clock).
> I hope this clarifies what I am trying to say here.
>
I thought so and now if you look at last part of my comment.

Rating of 32K based synctimer and 32K based GPTIMER
should be same because of the precision. That's the main
point why I was saying that GPTIMER is not a better
clock-source( with 32k clock src)  than sync timer when
both are enabled together.

Regards
Santosh

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
>> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
>> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>
>> [...]
>>
>> >
>> >> Btw, if you need PM, how are you going to use GPTIMER
>> >> as a clocksource. Note sys-clock is generally stopped in
>> >> low power states. So that leaves you option with using
>> >> gptimer with 32K clock and in that case, GPTIMER
>> >> is not a better clock-source compare to 32K sync timer
>> >> and so shouldn't be the rating.
>> >>
>> >
>> > AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
>> > Clocksource, without any issues.
>> >
>> GPTIMER1 is in wakeup domain on OMAP too but that doesn't
>> solve the issue I am talking. Once the sysclock is stopped, GPTIMER
>> can't tick anymore even if it is in wakeup domain.
>>
>> The only way it will work is using always running 32KHz clock as
>> the clock input to GPT1. And then the end result is the accuracy
>> of GPTIMER = sync 32K timer. So they are of same rating.
>>
>
> Ohh ok, sorry I should have clarified it in my last response itself.
>
np.

> AM33xx architecture is bit different than OMAP family, and gmtimer1 is
> sourced from RTC32K clock, which is in wakeup domain.
> This means we have RTC32K clock always running across suspend/resume.
>
> 0 - SEL1: Select CLK_M_OSC clock
> 1 - SEL2: Select CLK_32KHZ clock
> 2 - SEL3: Select TCLKIN clock
> 3 - SEL4: Select CLK_RC32K clock
> 4 - SEL5: Selects the CLK_32768 from 32KHz Crystal Osc
>
>
> We use value "4" here, for RTC32K (always on clock).
> I hope this clarifies what I am trying to say here.
>
I thought so and now if you look at last part of my comment.

Rating of 32K based synctimer and 32K based GPTIMER
should be same because of the precision. That's the main
point why I was saying that GPTIMER is not a better
clock-source( with 32k clock src)  than sync timer when
both are enabled together.

Regards
Santosh

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
> >> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> >> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>
> >> [...]
> >>
> >> >
> >> >> Btw, if you need PM, how are you going to use GPTIMER
> >> >> as a clocksource. Note sys-clock is generally stopped in
> >> >> low power states. So that leaves you option with using
> >> >> gptimer with 32K clock and in that case, GPTIMER
> >> >> is not a better clock-source compare to 32K sync timer
> >> >> and so shouldn't be the rating.
> >> >>
> >> >
> >> > AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
> >> > Clocksource, without any issues.
> >> >
> >> GPTIMER1 is in wakeup domain on OMAP too but that doesn't
> >> solve the issue I am talking. Once the sysclock is stopped, GPTIMER
> >> can't tick anymore even if it is in wakeup domain.
> >>
> >> The only way it will work is using always running 32KHz clock as
> >> the clock input to GPT1. And then the end result is the accuracy
> >> of GPTIMER = sync 32K timer. So they are of same rating.
> >>
> >
> > Ohh ok, sorry I should have clarified it in my last response itself.
> >
> np.
> 
> > AM33xx architecture is bit different than OMAP family, and gmtimer1 is
> > sourced from RTC32K clock, which is in wakeup domain.
> > This means we have RTC32K clock always running across suspend/resume.
> >
> > 0 - SEL1: Select CLK_M_OSC clock
> > 1 - SEL2: Select CLK_32KHZ clock
> > 2 - SEL3: Select TCLKIN clock
> > 3 - SEL4: Select CLK_RC32K clock
> > 4 - SEL5: Selects the CLK_32768 from 32KHz Crystal Osc
> >
> >
> > We use value "4" here, for RTC32K (always on clock).
> > I hope this clarifies what I am trying to say here.
> >
> I thought so and now if you look at last part of my comment.
> 
> Rating of 32K based synctimer and 32K based GPTIMER
> should be same because of the precision. That's the main
> point why I was saying that GPTIMER is not a better
> clock-source( with 32k clock src)  than sync timer when
> both are enabled together.
> 

Santosh,

In case of OMAP, we are using timer 2 for clocksource

OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)

And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER 
defined in our defconfig.

Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).


Let me propose this,

How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
And also, as mentioned by Santosh, I will register both the clocks as 
clocksource with the same rating.
By default, kernel is going to use 32k_counter as a clocksource, and through 
Command prompt user can override it without any issues.

Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.

Also, this way I can completely get rid of option CONFIG_OMAP_32K_TIMER_HZ.




diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 6b12372..ded78b7 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -45,6 +45,7 @@
 #include <plat/omap_hwmod.h>
 #include <plat/omap_device.h>
 #include <plat/omap-pm.h>
+#include <plat/clock.h>
 
 #include "powerdomain.h"
 
@@ -57,18 +58,18 @@
 #define OMAP3_32K_SOURCE	"omap_32k_fck"
 #define OMAP4_32K_SOURCE	"sys_32k_ck"
 
-#ifdef CONFIG_OMAP_32K_TIMER
+//#ifdef CONFIG_OMAP_32K_TIMER
 #define OMAP2_CLKEV_SOURCE	OMAP2_32K_SOURCE
 #define OMAP3_CLKEV_SOURCE	OMAP3_32K_SOURCE
 #define OMAP4_CLKEV_SOURCE	OMAP4_32K_SOURCE
 #define OMAP3_SECURE_TIMER	12
-#else
+/*#else
 #define OMAP2_CLKEV_SOURCE	OMAP2_MPU_SOURCE
 #define OMAP3_CLKEV_SOURCE	OMAP3_MPU_SOURCE
 #define OMAP4_CLKEV_SOURCE	OMAP4_MPU_SOURCE
 #define OMAP3_SECURE_TIMER	1
 #endif
-
+*/
 /* MAX_GPTIMER_ID: number of GPTIMERs on the chip */
 #define MAX_GPTIMER_ID		12
 
@@ -244,6 +245,7 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 
 /* Clocksource code */
 static struct omap_dm_timer clksrc;
+static bool is_dmtimer_clocksource;
 
 /*
  * clocksource
@@ -253,20 +255,38 @@ static cycle_t clocksource_read_cycles(struct clocksource *cs)
 	return (cycle_t)__omap_dm_timer_read_counter(&clksrc, 1);
 }
 
+static int clocksource_enable(struct clocksource *cs)
+{
+	__omap_dm_timer_load_start(&clksrc,
+			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR,
+			omap_32k_read_sched_clock(), 1);
+
+	is_dmtimer_clocksource = true;
+	return 0;
+}
+
+static void clocksource_disable(struct clocksource *cs)
+{
+	__omap_dm_timer_stop(&clksrc, 1, clksrc.rate);
+	is_dmtimer_clocksource = false;
+}
+
 static struct clocksource clocksource_gpt = {
 	.name		= "gp timer",
-	.rating		= 300,
+	.rating		= 250,
 	.read		= clocksource_read_cycles,
+	.enable		= clocksource_enable,
+	.disable	= clocksource_disable,
 	.mask		= CLOCKSOURCE_MASK(32),
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-static u32 notrace dmtimer_read_sched_clock(void)
+static u32 notrace read_sched_clock(void)
 {
-	if (clksrc.reserved)
+	if (is_dmtimer_clocksource && clksrc.reserved)
 		return __omap_dm_timer_read_counter(&clksrc, 1);
-
-	return 0;
+	else
+		return omap_32k_read_sched_clock();
 }
 
 /* Setup free-running counter for clocksource */
@@ -282,8 +302,8 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 	 * execution will fallback to gp-timer.
 	 */
 	res = omap_init_clocksource_32k();
-	if (!res)
-		return;
+	if (res)
+		pr_err("failed to init 32k_counter as a clocksource %d\n", res);
 
 	/* Fall back to gp-timer code */
 	res = omap_dm_timer_init_one(&clksrc, gptimer_id, fck_source);
@@ -292,9 +312,9 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 	pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
 		gptimer_id, clksrc.rate);
 
-	__omap_dm_timer_load_start(&clksrc,
-			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);
-	setup_sched_clock(dmtimer_read_sched_clock, 32, clksrc.rate);
+//	__omap_dm_timer_load_start(&clksrc,
+//			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);
+	setup_sched_clock(read_sched_clock, 32, clksrc.rate);
 
 	if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
 		pr_err("Could not register clocksource %s\n",
@@ -315,12 +335,12 @@ struct sys_timer omap##name##_timer = {					\
 };
 
 #ifdef CONFIG_ARCH_OMAP2
-OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
+OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP3_CLKEV_SOURCE)
 OMAP_SYS_TIMER(2)
 #endif
 
 #ifdef CONFIG_ARCH_OMAP3
-OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
+OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_CLKEV_SOURCE)
 OMAP_SYS_TIMER(3)
 OMAP_SYS_TIMER_INIT(3_secure, OMAP3_SECURE_TIMER, OMAP3_CLKEV_SOURCE,
 			2, OMAP3_MPU_SOURCE)
diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
index 5a25de0..4d65c2f 100644
--- a/arch/arm/plat-omap/counter_32k.c
+++ b/arch/arm/plat-omap/counter_32k.c
@@ -37,7 +37,7 @@ static void __iomem *timer_32k_base;
 
 #define OMAP16XX_TIMER_32K_SYNCHRONIZED		0xfffbc410
 
-static u32 notrace omap_32k_read_sched_clock(void)
+u32 notrace omap_32k_read_sched_clock(void)
 {
 	return timer_32k_base ? __raw_readl(timer_32k_base) : 0;
 }
@@ -118,7 +118,7 @@ int __init omap_init_clocksource_32k(void)
 		printk(KERN_ERR "%s: can't register clocksource!\n",
 				"32k_counter");
 
-	setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
+//	setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
 
 	return 0;
 }
diff --git a/arch/arm/plat-omap/include/plat/common.h b/arch/arm/plat-omap/include/plat/common.h
index b4d7ec3..4afb19b 100644
--- a/arch/arm/plat-omap/include/plat/common.h
+++ b/arch/arm/plat-omap/include/plat/common.h
@@ -31,6 +31,7 @@
 #include <plat/omap_hwmod.h>
 
 extern int __init omap_init_clocksource_32k(void);
+extern u32 notrace omap_32k_read_sched_clock(void);
 
 extern void omap_reserve(void);
 extern int omap_dss_reset(struct omap_hwmod *);


Thanks,
Vaibhav

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
> >> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> >> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>
> >> [...]
> >>
> >> >
> >> >> Btw, if you need PM, how are you going to use GPTIMER
> >> >> as a clocksource. Note sys-clock is generally stopped in
> >> >> low power states. So that leaves you option with using
> >> >> gptimer with 32K clock and in that case, GPTIMER
> >> >> is not a better clock-source compare to 32K sync timer
> >> >> and so shouldn't be the rating.
> >> >>
> >> >
> >> > AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
> >> > Clocksource, without any issues.
> >> >
> >> GPTIMER1 is in wakeup domain on OMAP too but that doesn't
> >> solve the issue I am talking. Once the sysclock is stopped, GPTIMER
> >> can't tick anymore even if it is in wakeup domain.
> >>
> >> The only way it will work is using always running 32KHz clock as
> >> the clock input to GPT1. And then the end result is the accuracy
> >> of GPTIMER = sync 32K timer. So they are of same rating.
> >>
> >
> > Ohh ok, sorry I should have clarified it in my last response itself.
> >
> np.
> 
> > AM33xx architecture is bit different than OMAP family, and gmtimer1 is
> > sourced from RTC32K clock, which is in wakeup domain.
> > This means we have RTC32K clock always running across suspend/resume.
> >
> > 0 - SEL1: Select CLK_M_OSC clock
> > 1 - SEL2: Select CLK_32KHZ clock
> > 2 - SEL3: Select TCLKIN clock
> > 3 - SEL4: Select CLK_RC32K clock
> > 4 - SEL5: Selects the CLK_32768 from 32KHz Crystal Osc
> >
> >
> > We use value "4" here, for RTC32K (always on clock).
> > I hope this clarifies what I am trying to say here.
> >
> I thought so and now if you look at last part of my comment.
> 
> Rating of 32K based synctimer and 32K based GPTIMER
> should be same because of the precision. That's the main
> point why I was saying that GPTIMER is not a better
> clock-source( with 32k clock src)  than sync timer when
> both are enabled together.
> 

Santosh,

In case of OMAP, we are using timer 2 for clocksource

OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)

And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER 
defined in our defconfig.

Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).


Let me propose this,

How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
And also, as mentioned by Santosh, I will register both the clocks as 
clocksource with the same rating.
By default, kernel is going to use 32k_counter as a clocksource, and through 
Command prompt user can override it without any issues.

Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.

Also, this way I can completely get rid of option CONFIG_OMAP_32K_TIMER_HZ.




diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 6b12372..ded78b7 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -45,6 +45,7 @@
 #include <plat/omap_hwmod.h>
 #include <plat/omap_device.h>
 #include <plat/omap-pm.h>
+#include <plat/clock.h>
 
 #include "powerdomain.h"
 
@@ -57,18 +58,18 @@
 #define OMAP3_32K_SOURCE	"omap_32k_fck"
 #define OMAP4_32K_SOURCE	"sys_32k_ck"
 
-#ifdef CONFIG_OMAP_32K_TIMER
+//#ifdef CONFIG_OMAP_32K_TIMER
 #define OMAP2_CLKEV_SOURCE	OMAP2_32K_SOURCE
 #define OMAP3_CLKEV_SOURCE	OMAP3_32K_SOURCE
 #define OMAP4_CLKEV_SOURCE	OMAP4_32K_SOURCE
 #define OMAP3_SECURE_TIMER	12
-#else
+/*#else
 #define OMAP2_CLKEV_SOURCE	OMAP2_MPU_SOURCE
 #define OMAP3_CLKEV_SOURCE	OMAP3_MPU_SOURCE
 #define OMAP4_CLKEV_SOURCE	OMAP4_MPU_SOURCE
 #define OMAP3_SECURE_TIMER	1
 #endif
-
+*/
 /* MAX_GPTIMER_ID: number of GPTIMERs on the chip */
 #define MAX_GPTIMER_ID		12
 
@@ -244,6 +245,7 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 
 /* Clocksource code */
 static struct omap_dm_timer clksrc;
+static bool is_dmtimer_clocksource;
 
 /*
  * clocksource
@@ -253,20 +255,38 @@ static cycle_t clocksource_read_cycles(struct clocksource *cs)
 	return (cycle_t)__omap_dm_timer_read_counter(&clksrc, 1);
 }
 
+static int clocksource_enable(struct clocksource *cs)
+{
+	__omap_dm_timer_load_start(&clksrc,
+			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR,
+			omap_32k_read_sched_clock(), 1);
+
+	is_dmtimer_clocksource = true;
+	return 0;
+}
+
+static void clocksource_disable(struct clocksource *cs)
+{
+	__omap_dm_timer_stop(&clksrc, 1, clksrc.rate);
+	is_dmtimer_clocksource = false;
+}
+
 static struct clocksource clocksource_gpt = {
 	.name		= "gp timer",
-	.rating		= 300,
+	.rating		= 250,
 	.read		= clocksource_read_cycles,
+	.enable		= clocksource_enable,
+	.disable	= clocksource_disable,
 	.mask		= CLOCKSOURCE_MASK(32),
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-static u32 notrace dmtimer_read_sched_clock(void)
+static u32 notrace read_sched_clock(void)
 {
-	if (clksrc.reserved)
+	if (is_dmtimer_clocksource && clksrc.reserved)
 		return __omap_dm_timer_read_counter(&clksrc, 1);
-
-	return 0;
+	else
+		return omap_32k_read_sched_clock();
 }
 
 /* Setup free-running counter for clocksource */
@@ -282,8 +302,8 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 	 * execution will fallback to gp-timer.
 	 */
 	res = omap_init_clocksource_32k();
-	if (!res)
-		return;
+	if (res)
+		pr_err("failed to init 32k_counter as a clocksource %d\n", res);
 
 	/* Fall back to gp-timer code */
 	res = omap_dm_timer_init_one(&clksrc, gptimer_id, fck_source);
@@ -292,9 +312,9 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 	pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
 		gptimer_id, clksrc.rate);
 
-	__omap_dm_timer_load_start(&clksrc,
-			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);
-	setup_sched_clock(dmtimer_read_sched_clock, 32, clksrc.rate);
+//	__omap_dm_timer_load_start(&clksrc,
+//			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);
+	setup_sched_clock(read_sched_clock, 32, clksrc.rate);
 
 	if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
 		pr_err("Could not register clocksource %s\n",
@@ -315,12 +335,12 @@ struct sys_timer omap##name##_timer = {					\
 };
 
 #ifdef CONFIG_ARCH_OMAP2
-OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
+OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP3_CLKEV_SOURCE)
 OMAP_SYS_TIMER(2)
 #endif
 
 #ifdef CONFIG_ARCH_OMAP3
-OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
+OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_CLKEV_SOURCE)
 OMAP_SYS_TIMER(3)
 OMAP_SYS_TIMER_INIT(3_secure, OMAP3_SECURE_TIMER, OMAP3_CLKEV_SOURCE,
 			2, OMAP3_MPU_SOURCE)
diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
index 5a25de0..4d65c2f 100644
--- a/arch/arm/plat-omap/counter_32k.c
+++ b/arch/arm/plat-omap/counter_32k.c
@@ -37,7 +37,7 @@ static void __iomem *timer_32k_base;
 
 #define OMAP16XX_TIMER_32K_SYNCHRONIZED		0xfffbc410
 
-static u32 notrace omap_32k_read_sched_clock(void)
+u32 notrace omap_32k_read_sched_clock(void)
 {
 	return timer_32k_base ? __raw_readl(timer_32k_base) : 0;
 }
@@ -118,7 +118,7 @@ int __init omap_init_clocksource_32k(void)
 		printk(KERN_ERR "%s: can't register clocksource!\n",
 				"32k_counter");
 
-	setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
+//	setup_sched_clock(omap_32k_read_sched_clock, 32, 32768);
 
 	return 0;
 }
diff --git a/arch/arm/plat-omap/include/plat/common.h b/arch/arm/plat-omap/include/plat/common.h
index b4d7ec3..4afb19b 100644
--- a/arch/arm/plat-omap/include/plat/common.h
+++ b/arch/arm/plat-omap/include/plat/common.h
@@ -31,6 +31,7 @@
 #include <plat/omap_hwmod.h>
 
 extern int __init omap_init_clocksource_32k(void);
+extern u32 notrace omap_32k_read_sched_clock(void);
 
 extern void omap_reserve(void);
 extern int omap_dss_reset(struct omap_hwmod *);


Thanks,
Vaibhav

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 23, 2012 at 13:50:25, Ming Lei wrote:
> On Wed, Mar 21, 2012 at 7:29 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Mon, Mar 19, 2012 at 17:14:30, Ming Lei wrote:
> >> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >
> >> > I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> >> > It will always use 32k-counter, and never fall back to dmtimer.
> >> >
> >> > Then the only options we have here is,
> >> >
> >> > 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
> >> >   Kernel pick up best rating clocksource out of these two.
> >> >
> >> >   In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
> >> >   Rating. User can choose the 32k-counter clocksource via bootargs.
> >> >
> >> >   Impact: without bootargs for clocksource selection, kernel will choose
> >> >     dmtimer, impacting loss of time during suspend/resume.
> >> >
> >> >
> >> > 2) Let the current code be as is, means, the clocksource registration will
> >> >   Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
> >> >   selection will be Controlled by Kconfig rules.
> >>
> >> How about the 3rd option?
> >>
> >> 3), take the way in your patch 1) at default, but will switch to
> >> register dmtimer
> >> directly and bypass 32k-counter if user need it via kernel parameter.
> >>
> >> As far as I can think of, the situations required for dmtimer are high-frequency
> >> perf sample and high precision trace points, so looks it is OK to take
> >> 32k-counter
> >> at default.
> >>
> > But if you register both the timers (dmtimer & 32ksync), then initially kernel will only pick up dmtimer, as this has better rating. And late in
> 
> Looks not so, I found that 32ksync is always selected as the default
> clocksource if both are registered.
> 

No. Kernel always chooses better-rated timer/counter for clocksource.
Please refer to the file 

"kernel/time/clocksource.c"

When you register any clocksource, the sequence is
	...
	clocksource_enqueue(cs);
	...
	clocksource_select();
	...

And clocksource_enqueue(), makes sure that the list of registered clocksource is always sorted by its rating. And clocksource_select()
Chooses best (first in the list) as a clocksource, unless you override
It using bootparams or sysfs.

Thanks,
Vaibhav

> > the boot sequence clocksource switch will happen, base on
> > kernel parameter (clocksource=).
> >
> > So logically dmtimer will be always used as a default here.
> 
> Not so at least on my Pandaboard.
> 
> 
> Thanks,
> -- 
> Ming Lei
> 

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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 23, 2012 at 13:50:25, Ming Lei wrote:
> On Wed, Mar 21, 2012 at 7:29 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Mon, Mar 19, 2012 at 17:14:30, Ming Lei wrote:
> >> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >
> >> > I think you made very good point here. With the above patch, we are almost missing the capability of registering dmtimer as a clocksource for OMAP.
> >> > It will always use 32k-counter, and never fall back to dmtimer.
> >> >
> >> > Then the only options we have here is,
> >> >
> >> > 1) Register both the timers, 32k-counter and dmtimer for clocksource; let
> >> > ? Kernel pick up best rating clocksource out of these two.
> >> >
> >> > ? In case of OMAP1/2/3/4, kernel will use dmtimer, since it has better
> >> > ? Rating. User can choose the 32k-counter clocksource via bootargs.
> >> >
> >> > ? Impact: without bootargs for clocksource selection, kernel will choose
> >> > ? ? dmtimer, impacting loss of time during suspend/resume.
> >> >
> >> >
> >> > 2) Let the current code be as is, means, the clocksource registration will
> >> > ? Happened based on "#ifdef CONFIG_OMAP_32K_TIMER" and this option
> >> > ? selection will be Controlled by Kconfig rules.
> >>
> >> How about the 3rd option?
> >>
> >> 3), take the way in your patch 1) at default, but will switch to
> >> register dmtimer
> >> directly and bypass 32k-counter if user need it via kernel parameter.
> >>
> >> As far as I can think of, the situations required for dmtimer are high-frequency
> >> perf sample and high precision trace points, so looks it is OK to take
> >> 32k-counter
> >> at default.
> >>
> > But if you register both the timers (dmtimer & 32ksync), then initially kernel will only pick up dmtimer, as this has better rating. And late in
> 
> Looks not so, I found that 32ksync is always selected as the default
> clocksource if both are registered.
> 

No. Kernel always chooses better-rated timer/counter for clocksource.
Please refer to the file 

"kernel/time/clocksource.c"

When you register any clocksource, the sequence is
	...
	clocksource_enqueue(cs);
	...
	clocksource_select();
	...

And clocksource_enqueue(), makes sure that the list of registered clocksource is always sorted by its rating. And clocksource_select()
Chooses best (first in the list) as a clocksource, unless you override
It using bootparams or sysfs.

Thanks,
Vaibhav

> > the boot sequence clocksource switch will happen, base on
> > kernel parameter (clocksource=).
> >
> > So logically dmtimer will be always used as a default here.
> 
> Not so at least on my Pandaboard.
> 
> 
> Thanks,
> -- 
> Ming Lei
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

[-- Attachment #1: Type: text/plain, Size: 5517 bytes --]

On Fri, Mar 30, 2012 at 12:04 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
>> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> > On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
>> >> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
>> >> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>> >> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>> >> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >>
[...]

>> I thought so and now if you look at last part of my comment.
>>
>> Rating of 32K based synctimer and 32K based GPTIMER
>> should be same because of the precision. That's the main
>> point why I was saying that GPTIMER is not a better
>> clock-source( with 32k clock src)  than sync timer when
>> both are enabled together.
>>
>
> Santosh,
>
> In case of OMAP, we are using timer 2 for clocksource
>
> OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
> OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
>
> And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER
> defined in our defconfig.
>
> Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).
>
>
> Let me propose this,
>
> How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
> And also, as mentioned by Santosh, I will register both the clocks as
> clocksource with the same rating.
> By default, kernel is going to use 32k_counter as a clocksource, and through
> Command prompt user can override it without any issues.
>
> Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.

Let's not make this more complicated. I guess below simple patch should sort
out the issue. I briefly tested it on OMAP4 and it works. let me know
if it helps AMxxx machines.

Regards
Santosh

>From 0a9283e26174d76ff2753ac88521b61a26b24e8f Mon Sep 17 00:00:00 2001
From: Santosh Shilimkar <santosh.shilimkar@ti.com>
Date: Fri, 30 Mar 2012 12:43:29 +0530
Subject: [PATCH] ARM: OMAP: Make OMAP clocksource source selection runtime.

Current OMAP code support couple of clocksource options based on compilation
flag. The 32KHz based sync timer and a gptimer based clock source which can
run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options.

1. 32KHz synctimer
2. Sysclock based(e.g 38.4 MHz) gptimer
3. 32KHz based gptimer.

The optional gptimer based clocksource was added so that it can give the
high precision than synctimer so expected usage was 2 and not 3. Unfortunatlly
option 2, clocksource doesn't meet the requirement of free-running clock
as per clocksource need. It stops in low power states when  sysclock is cut.
That makes gptimer based clocksource option useless for OMAP2/3/4 devices
with sysclock as a clock input. Option 3 will still work but it is no better'
than 32K synctimer based clocksource.

So ideally we can kill the gptimer based clocksource option but there are some
OMAP based derivative SoCs like AMXXXX which doesn't have synictimer hardware IP
and need to fallback on 32KHz based gptimer clocksource.

Considering above, make synctimer and gptimer clocksource runtime
selectable so that both OMAP and AMXXXX continue to use the same code.

Not-yet-signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
 arch/arm/mach-omap2/timer.c |   25 ++++++++-----------------
 1 files changed, 8 insertions(+), 17 deletions(-)

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index c512bac..3878e59 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 }

 /* Clocksource code */
-
-#ifdef CONFIG_OMAP_32K_TIMER
-/*
- * When 32k-timer is enabled, don't use GPTimer for clocksource
- * instead, just leave default clocksource which uses the 32k
- * sync counter.  See clocksource setup in plat-omap/counter_32k.c
- */
-
-static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
-{
-	omap_init_clocksource_32k();
-}
-
-#else
-
 static struct omap_dm_timer clksrc;

 /*
@@ -276,7 +261,7 @@ static u32 notrace dmtimer_read_sched_clock(void)
 }

 /* Setup free-running counter for clocksource */
-static void __init omap2_gp_clocksource_init(int gptimer_id,
+static void __init omap2_gptimer_clocksource_init(int gptimer_id,
 						const char *fck_source)
 {
 	int res;
@@ -295,7 +280,13 @@ static void __init omap2_gp_clocksource_init(int
gptimer_id,
 		pr_err("Could not register clocksource %s\n",
 			clocksource_gpt.name);
 }
-#endif
+
+static void __init omap2_gp_clocksource_init(int gptimer_id,
+                                                const char *fck_source)
+{
+	if (omap_init_clocksource_32k())
+		omap2_gptimer_clocksource_init(gptimer_id, fck_source);
+}

 #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src,			\
 				clksrc_nr, clksrc_src)			\
-- 
1.7.5.4

[-- Attachment #2: 0001-ARM-OMAP-Make-OMAP-clocksource-source-selection-runt.patch --]
[-- Type: application/octet-stream, Size: 3080 bytes --]

From 0a9283e26174d76ff2753ac88521b61a26b24e8f Mon Sep 17 00:00:00 2001
From: Santosh Shilimkar <santosh.shilimkar@ti.com>
Date: Fri, 30 Mar 2012 12:43:29 +0530
Subject: [PATCH] ARM: OMAP: Make OMAP clocksource source selection runtime.

Current OMAP code support couple of clocksource options based on compilation
flag. The 32KHz based sync timer and a gptimer based clock source which can
run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options.

1. 32KHz synctimer
2. Sysclock based(e.g 38.4 MHz) gptimer
3. 32KHz based gptimer.

The optional gptimer based clocksource was added so that it can give the
high precision than synctimer so expected usage was 2 and not 3. Unfortunatlly
option 2, clocksource doesn't meet the requirement of free-running clock
as per clocksource need. It stops in low power states when  sysclock is cut.
That makes gptimer based clocksource option useless for OMAP2/3/4 devices
with sysclock as a clock input. Option 3 will still work but it is no better'
than 32K synctimer based clocksource.

So ideally we can kill the gptimer based clocksource option but there are some
OMAP based derivative SoCs like AMXXXX which doesn't have synictimer hardware IP
and need to fallback on 32KHz based gptimer clocksource.

Considering above, make synctimer and gptimer clocksource runtime
selectable so that both OMAP and AMXXXX continue to use the same code.

Not-yet-signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
 arch/arm/mach-omap2/timer.c |   25 ++++++++-----------------
 1 files changed, 8 insertions(+), 17 deletions(-)

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index c512bac..3878e59 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 }
 
 /* Clocksource code */
-
-#ifdef CONFIG_OMAP_32K_TIMER
-/*
- * When 32k-timer is enabled, don't use GPTimer for clocksource
- * instead, just leave default clocksource which uses the 32k
- * sync counter.  See clocksource setup in plat-omap/counter_32k.c
- */
-
-static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
-{
-	omap_init_clocksource_32k();
-}
-
-#else
-
 static struct omap_dm_timer clksrc;
 
 /*
@@ -276,7 +261,7 @@ static u32 notrace dmtimer_read_sched_clock(void)
 }
 
 /* Setup free-running counter for clocksource */
-static void __init omap2_gp_clocksource_init(int gptimer_id,
+static void __init omap2_gptimer_clocksource_init(int gptimer_id,
 						const char *fck_source)
 {
 	int res;
@@ -295,7 +280,13 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 		pr_err("Could not register clocksource %s\n",
 			clocksource_gpt.name);
 }
-#endif
+
+static void __init omap2_gp_clocksource_init(int gptimer_id,
+                                                const char *fck_source)
+{
+	if (omap_init_clocksource_32k())
+		omap2_gptimer_clocksource_init(gptimer_id, fck_source);
+}
 
 #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src,			\
 				clksrc_nr, clksrc_src)			\
-- 
1.7.5.4

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Fri, Mar 30, 2012 at 12:04 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
>> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> > On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
>> >> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
>> >> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>> >> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>> >> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> >>
[...]

>> I thought so and now if you look at last part of my comment.
>>
>> Rating of 32K based synctimer and 32K based GPTIMER
>> should be same because of the precision. That's the main
>> point why I was saying that GPTIMER is not a better
>> clock-source( with 32k clock src) ?than sync timer when
>> both are enabled together.
>>
>
> Santosh,
>
> In case of OMAP, we are using timer 2 for clocksource
>
> OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
> OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
>
> And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER
> defined in our defconfig.
>
> Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).
>
>
> Let me propose this,
>
> How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
> And also, as mentioned by Santosh, I will register both the clocks as
> clocksource with the same rating.
> By default, kernel is going to use 32k_counter as a clocksource, and through
> Command prompt user can override it without any issues.
>
> Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.

Let's not make this more complicated. I guess below simple patch should sort
out the issue. I briefly tested it on OMAP4 and it works. let me know
if it helps AMxxx machines.

Regards
Santosh

>From 0a9283e26174d76ff2753ac88521b61a26b24e8f Mon Sep 17 00:00:00 2001
From: Santosh Shilimkar <santosh.shilimkar@ti.com>
Date: Fri, 30 Mar 2012 12:43:29 +0530
Subject: [PATCH] ARM: OMAP: Make OMAP clocksource source selection runtime.

Current OMAP code support couple of clocksource options based on compilation
flag. The 32KHz based sync timer and a gptimer based clock source which can
run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options.

1. 32KHz synctimer
2. Sysclock based(e.g 38.4 MHz) gptimer
3. 32KHz based gptimer.

The optional gptimer based clocksource was added so that it can give the
high precision than synctimer so expected usage was 2 and not 3. Unfortunatlly
option 2, clocksource doesn't meet the requirement of free-running clock
as per clocksource need. It stops in low power states when  sysclock is cut.
That makes gptimer based clocksource option useless for OMAP2/3/4 devices
with sysclock as a clock input. Option 3 will still work but it is no better'
than 32K synctimer based clocksource.

So ideally we can kill the gptimer based clocksource option but there are some
OMAP based derivative SoCs like AMXXXX which doesn't have synictimer hardware IP
and need to fallback on 32KHz based gptimer clocksource.

Considering above, make synctimer and gptimer clocksource runtime
selectable so that both OMAP and AMXXXX continue to use the same code.

Not-yet-signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
 arch/arm/mach-omap2/timer.c |   25 ++++++++-----------------
 1 files changed, 8 insertions(+), 17 deletions(-)

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index c512bac..3878e59 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 }

 /* Clocksource code */
-
-#ifdef CONFIG_OMAP_32K_TIMER
-/*
- * When 32k-timer is enabled, don't use GPTimer for clocksource
- * instead, just leave default clocksource which uses the 32k
- * sync counter.  See clocksource setup in plat-omap/counter_32k.c
- */
-
-static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
-{
-	omap_init_clocksource_32k();
-}
-
-#else
-
 static struct omap_dm_timer clksrc;

 /*
@@ -276,7 +261,7 @@ static u32 notrace dmtimer_read_sched_clock(void)
 }

 /* Setup free-running counter for clocksource */
-static void __init omap2_gp_clocksource_init(int gptimer_id,
+static void __init omap2_gptimer_clocksource_init(int gptimer_id,
 						const char *fck_source)
 {
 	int res;
@@ -295,7 +280,13 @@ static void __init omap2_gp_clocksource_init(int
gptimer_id,
 		pr_err("Could not register clocksource %s\n",
 			clocksource_gpt.name);
 }
-#endif
+
+static void __init omap2_gp_clocksource_init(int gptimer_id,
+                                                const char *fck_source)
+{
+	if (omap_init_clocksource_32k())
+		omap2_gptimer_clocksource_init(gptimer_id, fck_source);
+}

 #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src,			\
 				clksrc_nr, clksrc_src)			\
-- 
1.7.5.4
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RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
> On Fri, Mar 30, 2012 at 12:04 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
> >> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> > On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
> >> >> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> >> >> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >> >> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >> >> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >>
> [...]
> 
> >> I thought so and now if you look at last part of my comment.
> >>
> >> Rating of 32K based synctimer and 32K based GPTIMER
> >> should be same because of the precision. That's the main
> >> point why I was saying that GPTIMER is not a better
> >> clock-source( with 32k clock src)  than sync timer when
> >> both are enabled together.
> >>
> >
> > Santosh,
> >
> > In case of OMAP, we are using timer 2 for clocksource
> >
> > OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
> > OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
> >
> > And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER
> > defined in our defconfig.
> >
> > Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).
> >
> >
> > Let me propose this,
> >
> > How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
> > And also, as mentioned by Santosh, I will register both the clocks as
> > clocksource with the same rating.
> > By default, kernel is going to use 32k_counter as a clocksource, and through
> > Command prompt user can override it without any issues.
> >
> > Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.
> 
> Let's not make this more complicated. I guess below simple patch should sort
> out the issue. I briefly tested it on OMAP4 and it works. let me know
> if it helps AMxxx machines.
> 
> Regards
> Santosh
> 
> From 0a9283e26174d76ff2753ac88521b61a26b24e8f Mon Sep 17 00:00:00 2001
> From: Santosh Shilimkar <santosh.shilimkar@ti.com>
> Date: Fri, 30 Mar 2012 12:43:29 +0530
> Subject: [PATCH] ARM: OMAP: Make OMAP clocksource source selection runtime.
> 
> Current OMAP code support couple of clocksource options based on compilation
> flag. The 32KHz based sync timer and a gptimer based clock source which can
> run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options.
> 
> 1. 32KHz synctimer
> 2. Sysclock based(e.g 38.4 MHz) gptimer
> 3. 32KHz based gptimer.
> 
> The optional gptimer based clocksource was added so that it can give the
> high precision than synctimer so expected usage was 2 and not 3. Unfortunatlly
> option 2, clocksource doesn't meet the requirement of free-running clock
> as per clocksource need. It stops in low power states when  sysclock is cut.
> That makes gptimer based clocksource option useless for OMAP2/3/4 devices
> with sysclock as a clock input. Option 3 will still work but it is no better'
> than 32K synctimer based clocksource.
> 
> So ideally we can kill the gptimer based clocksource option but there are some
> OMAP based derivative SoCs like AMXXXX which doesn't have synictimer hardware IP
> and need to fallback on 32KHz based gptimer clocksource.
> 
> Considering above, make synctimer and gptimer clocksource runtime
> selectable so that both OMAP and AMXXXX continue to use the same code.
> 
> Not-yet-signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> ---
>  arch/arm/mach-omap2/timer.c |   25 ++++++++-----------------
>  1 files changed, 8 insertions(+), 17 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
> index c512bac..3878e59 100644
> --- a/arch/arm/mach-omap2/timer.c
> +++ b/arch/arm/mach-omap2/timer.c
> @@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
>  }
> 
>  /* Clocksource code */
> -
> -#ifdef CONFIG_OMAP_32K_TIMER
> -/*
> - * When 32k-timer is enabled, don't use GPTimer for clocksource
> - * instead, just leave default clocksource which uses the 32k
> - * sync counter.  See clocksource setup in plat-omap/counter_32k.c
> - */
> -
> -static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
> -{
> -	omap_init_clocksource_32k();
> -}
> -
> -#else
> -
>  static struct omap_dm_timer clksrc;
> 
>  /*
> @@ -276,7 +261,7 @@ static u32 notrace dmtimer_read_sched_clock(void)
>  }
> 
>  /* Setup free-running counter for clocksource */
> -static void __init omap2_gp_clocksource_init(int gptimer_id,
> +static void __init omap2_gptimer_clocksource_init(int gptimer_id,
>  						const char *fck_source)
>  {
>  	int res;
> @@ -295,7 +280,13 @@ static void __init omap2_gp_clocksource_init(int
> gptimer_id,
>  		pr_err("Could not register clocksource %s\n",
>  			clocksource_gpt.name);
>  }
> -#endif
> +
> +static void __init omap2_gp_clocksource_init(int gptimer_id,
> +                                                const char *fck_source)
> +{
> +	if (omap_init_clocksource_32k())
> +		omap2_gptimer_clocksource_init(gptimer_id, fck_source);
> +}
> 

With this patch, will you be able to choose gptimer as a clocksource
using bootparameter (or sysfs) for given kernel uImage?

The answer is simply NO...as the registration of gptimer is based on
failure from omap_init_clocksource_32k(). And this is nothing different 
than my original patch, my patch exactly does same thing.

The requirement after 'ming Lie' response on my patch was, there will be
usecases where we might need to use gptimer for clocksource and with 
the patch it is not possible, since you will only register 
32k_counter here.

So in order to allow user to choose between 32K and gptimer, you must 
register both and make 32k as a default thing.


Thanks,
Vaibhav

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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
> On Fri, Mar 30, 2012 at 12:04 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
> >> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> > On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
> >> >> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >> > On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> >> >> >> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >> >> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >> >> >> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >> >> >> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> >>
> [...]
> 
> >> I thought so and now if you look at last part of my comment.
> >>
> >> Rating of 32K based synctimer and 32K based GPTIMER
> >> should be same because of the precision. That's the main
> >> point why I was saying that GPTIMER is not a better
> >> clock-source( with 32k clock src) ?than sync timer when
> >> both are enabled together.
> >>
> >
> > Santosh,
> >
> > In case of OMAP, we are using timer 2 for clocksource
> >
> > OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
> > OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
> >
> > And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER
> > defined in our defconfig.
> >
> > Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).
> >
> >
> > Let me propose this,
> >
> > How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
> > And also, as mentioned by Santosh, I will register both the clocks as
> > clocksource with the same rating.
> > By default, kernel is going to use 32k_counter as a clocksource, and through
> > Command prompt user can override it without any issues.
> >
> > Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.
> 
> Let's not make this more complicated. I guess below simple patch should sort
> out the issue. I briefly tested it on OMAP4 and it works. let me know
> if it helps AMxxx machines.
> 
> Regards
> Santosh
> 
> From 0a9283e26174d76ff2753ac88521b61a26b24e8f Mon Sep 17 00:00:00 2001
> From: Santosh Shilimkar <santosh.shilimkar@ti.com>
> Date: Fri, 30 Mar 2012 12:43:29 +0530
> Subject: [PATCH] ARM: OMAP: Make OMAP clocksource source selection runtime.
> 
> Current OMAP code support couple of clocksource options based on compilation
> flag. The 32KHz based sync timer and a gptimer based clock source which can
> run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options.
> 
> 1. 32KHz synctimer
> 2. Sysclock based(e.g 38.4 MHz) gptimer
> 3. 32KHz based gptimer.
> 
> The optional gptimer based clocksource was added so that it can give the
> high precision than synctimer so expected usage was 2 and not 3. Unfortunatlly
> option 2, clocksource doesn't meet the requirement of free-running clock
> as per clocksource need. It stops in low power states when  sysclock is cut.
> That makes gptimer based clocksource option useless for OMAP2/3/4 devices
> with sysclock as a clock input. Option 3 will still work but it is no better'
> than 32K synctimer based clocksource.
> 
> So ideally we can kill the gptimer based clocksource option but there are some
> OMAP based derivative SoCs like AMXXXX which doesn't have synictimer hardware IP
> and need to fallback on 32KHz based gptimer clocksource.
> 
> Considering above, make synctimer and gptimer clocksource runtime
> selectable so that both OMAP and AMXXXX continue to use the same code.
> 
> Not-yet-signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> ---
>  arch/arm/mach-omap2/timer.c |   25 ++++++++-----------------
>  1 files changed, 8 insertions(+), 17 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
> index c512bac..3878e59 100644
> --- a/arch/arm/mach-omap2/timer.c
> +++ b/arch/arm/mach-omap2/timer.c
> @@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
>  }
> 
>  /* Clocksource code */
> -
> -#ifdef CONFIG_OMAP_32K_TIMER
> -/*
> - * When 32k-timer is enabled, don't use GPTimer for clocksource
> - * instead, just leave default clocksource which uses the 32k
> - * sync counter.  See clocksource setup in plat-omap/counter_32k.c
> - */
> -
> -static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
> -{
> -	omap_init_clocksource_32k();
> -}
> -
> -#else
> -
>  static struct omap_dm_timer clksrc;
> 
>  /*
> @@ -276,7 +261,7 @@ static u32 notrace dmtimer_read_sched_clock(void)
>  }
> 
>  /* Setup free-running counter for clocksource */
> -static void __init omap2_gp_clocksource_init(int gptimer_id,
> +static void __init omap2_gptimer_clocksource_init(int gptimer_id,
>  						const char *fck_source)
>  {
>  	int res;
> @@ -295,7 +280,13 @@ static void __init omap2_gp_clocksource_init(int
> gptimer_id,
>  		pr_err("Could not register clocksource %s\n",
>  			clocksource_gpt.name);
>  }
> -#endif
> +
> +static void __init omap2_gp_clocksource_init(int gptimer_id,
> +                                                const char *fck_source)
> +{
> +	if (omap_init_clocksource_32k())
> +		omap2_gptimer_clocksource_init(gptimer_id, fck_source);
> +}
> 

With this patch, will you be able to choose gptimer as a clocksource
using bootparameter (or sysfs) for given kernel uImage?

The answer is simply NO...as the registration of gptimer is based on
failure from omap_init_clocksource_32k(). And this is nothing different 
than my original patch, my patch exactly does same thing.

The requirement after 'ming Lie' response on my patch was, there will be
usecases where we might need to use gptimer for clocksource and with 
the patch it is not possible, since you will only register 
32k_counter here.

So in order to allow user to choose between 32K and gptimer, you must 
register both and make 32k as a default thing.


Thanks,
Vaibhav

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
> On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
>> On Fri, Mar 30, 2012 at 12:04 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>> On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
>>>> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>> On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
>>>>>> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>>>> On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
>>>>>>>> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>>>>>> On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>>>>>>>>>> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>>>>>>>>>>> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>>>
>> [...]
>>
>>>> I thought so and now if you look at last part of my comment.
>>>>
>>>> Rating of 32K based synctimer and 32K based GPTIMER
>>>> should be same because of the precision. That's the main
>>>> point why I was saying that GPTIMER is not a better
>>>> clock-source( with 32k clock src)  than sync timer when
>>>> both are enabled together.
>>>>
>>>
>>> Santosh,
>>>
>>> In case of OMAP, we are using timer 2 for clocksource
>>>
>>> OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
>>> OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
>>>
>>> And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER
>>> defined in our defconfig.
>>>
>>> Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).
>>>
>>>
>>> Let me propose this,
>>>
>>> How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
>>> And also, as mentioned by Santosh, I will register both the clocks as
>>> clocksource with the same rating.
>>> By default, kernel is going to use 32k_counter as a clocksource, and through
>>> Command prompt user can override it without any issues.
>>>
>>> Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.
>>
>> Let's not make this more complicated. I guess below simple patch should sort
>> out the issue. I briefly tested it on OMAP4 and it works. let me know
>> if it helps AMxxx machines.
>>
>> Regards
>> Santosh
>>
>> From 0a9283e26174d76ff2753ac88521b61a26b24e8f Mon Sep 17 00:00:00 2001
>> From: Santosh Shilimkar <santosh.shilimkar@ti.com>
>> Date: Fri, 30 Mar 2012 12:43:29 +0530
>> Subject: [PATCH] ARM: OMAP: Make OMAP clocksource source selection runtime.
>>
>> Current OMAP code support couple of clocksource options based on compilation
>> flag. The 32KHz based sync timer and a gptimer based clock source which can
>> run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options.
>>
>> 1. 32KHz synctimer
>> 2. Sysclock based(e.g 38.4 MHz) gptimer
>> 3. 32KHz based gptimer.
>>
>> The optional gptimer based clocksource was added so that it can give the
>> high precision than synctimer so expected usage was 2 and not 3. Unfortunatlly
>> option 2, clocksource doesn't meet the requirement of free-running clock
>> as per clocksource need. It stops in low power states when  sysclock is cut.
>> That makes gptimer based clocksource option useless for OMAP2/3/4 devices
>> with sysclock as a clock input. Option 3 will still work but it is no better'
>> than 32K synctimer based clocksource.
>>
>> So ideally we can kill the gptimer based clocksource option but there are some
>> OMAP based derivative SoCs like AMXXXX which doesn't have synictimer hardware IP
>> and need to fallback on 32KHz based gptimer clocksource.
>>
>> Considering above, make synctimer and gptimer clocksource runtime
>> selectable so that both OMAP and AMXXXX continue to use the same code.
>>
>> Not-yet-signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
>> ---
>>  arch/arm/mach-omap2/timer.c |   25 ++++++++-----------------
>>  1 files changed, 8 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
>> index c512bac..3878e59 100644
>> --- a/arch/arm/mach-omap2/timer.c
>> +++ b/arch/arm/mach-omap2/timer.c
>> @@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
>>  }
>>
>>  /* Clocksource code */
>> -
>> -#ifdef CONFIG_OMAP_32K_TIMER
>> -/*
>> - * When 32k-timer is enabled, don't use GPTimer for clocksource
>> - * instead, just leave default clocksource which uses the 32k
>> - * sync counter.  See clocksource setup in plat-omap/counter_32k.c
>> - */
>> -
>> -static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
>> -{
>> -	omap_init_clocksource_32k();
>> -}
>> -
>> -#else
>> -
>>  static struct omap_dm_timer clksrc;
>>
>>  /*
>> @@ -276,7 +261,7 @@ static u32 notrace dmtimer_read_sched_clock(void)
>>  }
>>
>>  /* Setup free-running counter for clocksource */
>> -static void __init omap2_gp_clocksource_init(int gptimer_id,
>> +static void __init omap2_gptimer_clocksource_init(int gptimer_id,
>>  						const char *fck_source)
>>  {
>>  	int res;
>> @@ -295,7 +280,13 @@ static void __init omap2_gp_clocksource_init(int
>> gptimer_id,
>>  		pr_err("Could not register clocksource %s\n",
>>  			clocksource_gpt.name);
>>  }
>> -#endif
>> +
>> +static void __init omap2_gp_clocksource_init(int gptimer_id,
>> +                                                const char *fck_source)
>> +{
>> +	if (omap_init_clocksource_32k())
>> +		omap2_gptimer_clocksource_init(gptimer_id, fck_source);
>> +}
>>
> 
> With this patch, will you be able to choose gptimer as a clocksource
> using bootparameter (or sysfs) for given kernel uImage?
> 
Why do you want that ? Look at changelog. The gptimer based clocksource
is useless for OMAP and for AM devices synctimer is not available.


> The answer is simply NO...as the registration of gptimer is based on
> failure from omap_init_clocksource_32k(). And this is nothing different 
> than my original patch, my patch exactly does same thing.
> 
I ight have missed your original patch. If that patch is similar then
no problems.

> The requirement after 'ming Lie' response on my patch was, there will be
> usecases where we might need to use gptimer for clocksource and with 
> the patch it is not possible, since you will only register 
> 32k_counter here.
> 
I think Ming Lie might have expected that gptimer clocksource might
be better which is not the case.

> So in order to allow user to choose between 32K and gptimer, you must 
> register both and make 32k as a default thing.
> 
As described in the commit log, its not needed at all. Let's not add
a feature which is just useless because the gptimer based clock
source has no advantage against the syntimer.

Hope this clarifies.

Regards
Santosh

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
> On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
>> On Fri, Mar 30, 2012 at 12:04 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>> On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
>>>> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>> On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
>>>>>> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>>>> On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
>>>>>>>> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>>>>>> On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>>>>>>>>>> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>>>>>>>>>>> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>>>
>> [...]
>>
>>>> I thought so and now if you look at last part of my comment.
>>>>
>>>> Rating of 32K based synctimer and 32K based GPTIMER
>>>> should be same because of the precision. That's the main
>>>> point why I was saying that GPTIMER is not a better
>>>> clock-source( with 32k clock src)  than sync timer when
>>>> both are enabled together.
>>>>
>>>
>>> Santosh,
>>>
>>> In case of OMAP, we are using timer 2 for clocksource
>>>
>>> OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
>>> OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
>>>
>>> And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER
>>> defined in our defconfig.
>>>
>>> Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).
>>>
>>>
>>> Let me propose this,
>>>
>>> How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
>>> And also, as mentioned by Santosh, I will register both the clocks as
>>> clocksource with the same rating.
>>> By default, kernel is going to use 32k_counter as a clocksource, and through
>>> Command prompt user can override it without any issues.
>>>
>>> Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.
>>
>> Let's not make this more complicated. I guess below simple patch should sort
>> out the issue. I briefly tested it on OMAP4 and it works. let me know
>> if it helps AMxxx machines.
>>
>> Regards
>> Santosh
>>
>> From 0a9283e26174d76ff2753ac88521b61a26b24e8f Mon Sep 17 00:00:00 2001
>> From: Santosh Shilimkar <santosh.shilimkar@ti.com>
>> Date: Fri, 30 Mar 2012 12:43:29 +0530
>> Subject: [PATCH] ARM: OMAP: Make OMAP clocksource source selection runtime.
>>
>> Current OMAP code support couple of clocksource options based on compilation
>> flag. The 32KHz based sync timer and a gptimer based clock source which can
>> run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options.
>>
>> 1. 32KHz synctimer
>> 2. Sysclock based(e.g 38.4 MHz) gptimer
>> 3. 32KHz based gptimer.
>>
>> The optional gptimer based clocksource was added so that it can give the
>> high precision than synctimer so expected usage was 2 and not 3. Unfortunatlly
>> option 2, clocksource doesn't meet the requirement of free-running clock
>> as per clocksource need. It stops in low power states when  sysclock is cut.
>> That makes gptimer based clocksource option useless for OMAP2/3/4 devices
>> with sysclock as a clock input. Option 3 will still work but it is no better'
>> than 32K synctimer based clocksource.
>>
>> So ideally we can kill the gptimer based clocksource option but there are some
>> OMAP based derivative SoCs like AMXXXX which doesn't have synictimer hardware IP
>> and need to fallback on 32KHz based gptimer clocksource.
>>
>> Considering above, make synctimer and gptimer clocksource runtime
>> selectable so that both OMAP and AMXXXX continue to use the same code.
>>
>> Not-yet-signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
>> ---
>>  arch/arm/mach-omap2/timer.c |   25 ++++++++-----------------
>>  1 files changed, 8 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
>> index c512bac..3878e59 100644
>> --- a/arch/arm/mach-omap2/timer.c
>> +++ b/arch/arm/mach-omap2/timer.c
>> @@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
>>  }
>>
>>  /* Clocksource code */
>> -
>> -#ifdef CONFIG_OMAP_32K_TIMER
>> -/*
>> - * When 32k-timer is enabled, don't use GPTimer for clocksource
>> - * instead, just leave default clocksource which uses the 32k
>> - * sync counter.  See clocksource setup in plat-omap/counter_32k.c
>> - */
>> -
>> -static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
>> -{
>> -	omap_init_clocksource_32k();
>> -}
>> -
>> -#else
>> -
>>  static struct omap_dm_timer clksrc;
>>
>>  /*
>> @@ -276,7 +261,7 @@ static u32 notrace dmtimer_read_sched_clock(void)
>>  }
>>
>>  /* Setup free-running counter for clocksource */
>> -static void __init omap2_gp_clocksource_init(int gptimer_id,
>> +static void __init omap2_gptimer_clocksource_init(int gptimer_id,
>>  						const char *fck_source)
>>  {
>>  	int res;
>> @@ -295,7 +280,13 @@ static void __init omap2_gp_clocksource_init(int
>> gptimer_id,
>>  		pr_err("Could not register clocksource %s\n",
>>  			clocksource_gpt.name);
>>  }
>> -#endif
>> +
>> +static void __init omap2_gp_clocksource_init(int gptimer_id,
>> +                                                const char *fck_source)
>> +{
>> +	if (omap_init_clocksource_32k())
>> +		omap2_gptimer_clocksource_init(gptimer_id, fck_source);
>> +}
>>
> 
> With this patch, will you be able to choose gptimer as a clocksource
> using bootparameter (or sysfs) for given kernel uImage?
> 
Why do you want that ? Look at changelog. The gptimer based clocksource
is useless for OMAP and for AM devices synctimer is not available.


> The answer is simply NO...as the registration of gptimer is based on
> failure from omap_init_clocksource_32k(). And this is nothing different 
> than my original patch, my patch exactly does same thing.
> 
I ight have missed your original patch. If that patch is similar then
no problems.

> The requirement after 'ming Lie' response on my patch was, there will be
> usecases where we might need to use gptimer for clocksource and with 
> the patch it is not possible, since you will only register 
> 32k_counter here.
> 
I think Ming Lie might have expected that gptimer clocksource might
be better which is not the case.

> So in order to allow user to choose between 32K and gptimer, you must 
> register both and make 32k as a default thing.
> 
As described in the commit log, its not needed at all. Let's not add
a feature which is just useless because the gptimer based clock
source has no advantage against the syntimer.

Hope this clarifies.

Regards
Santosh

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
> >> On Fri, Mar 30, 2012 at 12:04 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>> On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
> >>>> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>>>> On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
> >>>>>> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>>>>>> On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> >>>>>>>> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>>>>>>>> On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >>>>>>>>>> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >>>>>>>>>>> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>>>>>
> >> [...]
> >>
> >>>> I thought so and now if you look at last part of my comment.
> >>>>
> >>>> Rating of 32K based synctimer and 32K based GPTIMER
> >>>> should be same because of the precision. That's the main
> >>>> point why I was saying that GPTIMER is not a better
> >>>> clock-source( with 32k clock src)  than sync timer when
> >>>> both are enabled together.
> >>>>
> >>>
> >>> Santosh,
> >>>
> >>> In case of OMAP, we are using timer 2 for clocksource
> >>>
> >>> OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
> >>> OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
> >>>
> >>> And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER
> >>> defined in our defconfig.
> >>>
> >>> Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).
> >>>
> >>>
> >>> Let me propose this,
> >>>
> >>> How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
> >>> And also, as mentioned by Santosh, I will register both the clocks as
> >>> clocksource with the same rating.
> >>> By default, kernel is going to use 32k_counter as a clocksource, and through
> >>> Command prompt user can override it without any issues.
> >>>
> >>> Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.
> >>
> >> Let's not make this more complicated. I guess below simple patch should sort
> >> out the issue. I briefly tested it on OMAP4 and it works. let me know
> >> if it helps AMxxx machines.
> >>
> >> Regards
> >> Santosh
> >>
> >> From 0a9283e26174d76ff2753ac88521b61a26b24e8f Mon Sep 17 00:00:00 2001
> >> From: Santosh Shilimkar <santosh.shilimkar@ti.com>
> >> Date: Fri, 30 Mar 2012 12:43:29 +0530
> >> Subject: [PATCH] ARM: OMAP: Make OMAP clocksource source selection runtime.
> >>
> >> Current OMAP code support couple of clocksource options based on compilation
> >> flag. The 32KHz based sync timer and a gptimer based clock source which can
> >> run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options.
> >>
> >> 1. 32KHz synctimer
> >> 2. Sysclock based(e.g 38.4 MHz) gptimer
> >> 3. 32KHz based gptimer.
> >>
> >> The optional gptimer based clocksource was added so that it can give the
> >> high precision than synctimer so expected usage was 2 and not 3. Unfortunatlly
> >> option 2, clocksource doesn't meet the requirement of free-running clock
> >> as per clocksource need. It stops in low power states when  sysclock is cut.
> >> That makes gptimer based clocksource option useless for OMAP2/3/4 devices
> >> with sysclock as a clock input. Option 3 will still work but it is no better'
> >> than 32K synctimer based clocksource.
> >>
> >> So ideally we can kill the gptimer based clocksource option but there are some
> >> OMAP based derivative SoCs like AMXXXX which doesn't have synictimer hardware IP
> >> and need to fallback on 32KHz based gptimer clocksource.
> >>
> >> Considering above, make synctimer and gptimer clocksource runtime
> >> selectable so that both OMAP and AMXXXX continue to use the same code.
> >>
> >> Not-yet-signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> >> ---
> >>  arch/arm/mach-omap2/timer.c |   25 ++++++++-----------------
> >>  1 files changed, 8 insertions(+), 17 deletions(-)
> >>
> >> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
> >> index c512bac..3878e59 100644
> >> --- a/arch/arm/mach-omap2/timer.c
> >> +++ b/arch/arm/mach-omap2/timer.c
> >> @@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
> >>  }
> >>
> >>  /* Clocksource code */
> >> -
> >> -#ifdef CONFIG_OMAP_32K_TIMER
> >> -/*
> >> - * When 32k-timer is enabled, don't use GPTimer for clocksource
> >> - * instead, just leave default clocksource which uses the 32k
> >> - * sync counter.  See clocksource setup in plat-omap/counter_32k.c
> >> - */
> >> -
> >> -static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
> >> -{
> >> -	omap_init_clocksource_32k();
> >> -}
> >> -
> >> -#else
> >> -
> >>  static struct omap_dm_timer clksrc;
> >>
> >>  /*
> >> @@ -276,7 +261,7 @@ static u32 notrace dmtimer_read_sched_clock(void)
> >>  }
> >>
> >>  /* Setup free-running counter for clocksource */
> >> -static void __init omap2_gp_clocksource_init(int gptimer_id,
> >> +static void __init omap2_gptimer_clocksource_init(int gptimer_id,
> >>  						const char *fck_source)
> >>  {
> >>  	int res;
> >> @@ -295,7 +280,13 @@ static void __init omap2_gp_clocksource_init(int
> >> gptimer_id,
> >>  		pr_err("Could not register clocksource %s\n",
> >>  			clocksource_gpt.name);
> >>  }
> >> -#endif
> >> +
> >> +static void __init omap2_gp_clocksource_init(int gptimer_id,
> >> +                                                const char *fck_source)
> >> +{
> >> +	if (omap_init_clocksource_32k())
> >> +		omap2_gptimer_clocksource_init(gptimer_id, fck_source);
> >> +}
> >>
> > 
> > With this patch, will you be able to choose gptimer as a clocksource
> > using bootparameter (or sysfs) for given kernel uImage?
> > 
> Why do you want that ? Look at changelog. The gptimer based clocksource
> is useless for OMAP and for AM devices synctimer is not available.
> 
> 
> > The answer is simply NO...as the registration of gptimer is based on
> > failure from omap_init_clocksource_32k(). And this is nothing different 
> > than my original patch, my patch exactly does same thing.
> > 
> I ight have missed your original patch. If that patch is similar then
> no problems.
> 
> > The requirement after 'ming Lie' response on my patch was, there will be
> > usecases where we might need to use gptimer for clocksource and with 
> > the patch it is not possible, since you will only register 
> > 32k_counter here.
> > 
> I think Ming Lie might have expected that gptimer clocksource might
> be better which is not the case.
> 
> > So in order to allow user to choose between 32K and gptimer, you must 
> > register both and make 32k as a default thing.
> > 
> As described in the commit log, its not needed at all. Let's not add
> a feature which is just useless because the gptimer based clock
> source has no advantage against the syntimer.
> 

I completely agree with you, and that is my understanding too.

After Ming Lie's comment, the point that I came to my mind was,
certainly there will be resolution difference between these two clocksources,
if  gptimer2 is sourced from sys_ck (26Mhz).

I am quite not sure, whether will there be any practical usecase where you
change the kernel clocksource for high resolution dynamically through sysfs 
or something. May be not....but still it is possible.


In that case my original patch still holds good here. I would still request
you to review the same and give your acked-by  or tested-by.


Thanks,
Vaibhav 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
> >> On Fri, Mar 30, 2012 at 12:04 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>> On Wed, Mar 28, 2012 at 20:19:07, Shilimkar, Santosh wrote:
> >>>> On Wed, Mar 28, 2012 at 8:07 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>>>> On Wed, Mar 28, 2012 at 19:50:02, Shilimkar, Santosh wrote:
> >>>>>> On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>>>>>> On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
> >>>>>>>> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>>>>>>>> On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
> >>>>>>>>>> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
> >>>>>>>>>>> On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >>>>>>
> >> [...]
> >>
> >>>> I thought so and now if you look at last part of my comment.
> >>>>
> >>>> Rating of 32K based synctimer and 32K based GPTIMER
> >>>> should be same because of the precision. That's the main
> >>>> point why I was saying that GPTIMER is not a better
> >>>> clock-source( with 32k clock src)  than sync timer when
> >>>> both are enabled together.
> >>>>
> >>>
> >>> Santosh,
> >>>
> >>> In case of OMAP, we are using timer 2 for clocksource
> >>>
> >>> OMAP_SYS_TIMER_INIT(2, 1, OMAP2_CLKEV_SOURCE, 2, OMAP2_MPU_SOURCE)
> >>> OMAP_SYS_TIMER_INIT(3, 1, OMAP3_CLKEV_SOURCE, 2, OMAP3_MPU_SOURCE)
> >>>
> >>> And timer2 as clocksource is never used, since we have CONFIG_OMAP_32K_TIMER
> >>> defined in our defconfig.
> >>>
> >>> Also, after looking at the code, I came across another problem, setup_sched_clock(). But this can be easily fixed, if we source both the timers with same clock (here 32k_fck).
> >>>
> >>>
> >>> Let me propose this,
> >>>
> >>> How about, if I keep timer2 source always set to 32k_fclk for omap2,3,4?
> >>> And also, as mentioned by Santosh, I will register both the clocks as
> >>> clocksource with the same rating.
> >>> By default, kernel is going to use 32k_counter as a clocksource, and through
> >>> Command prompt user can override it without any issues.
> >>>
> >>> Just to make sure that, whatever I am trying to propse here works and don't get into unknown issue; I changed my code for this, and it is working for me without any issues.
> >>
> >> Let's not make this more complicated. I guess below simple patch should sort
> >> out the issue. I briefly tested it on OMAP4 and it works. let me know
> >> if it helps AMxxx machines.
> >>
> >> Regards
> >> Santosh
> >>
> >> From 0a9283e26174d76ff2753ac88521b61a26b24e8f Mon Sep 17 00:00:00 2001
> >> From: Santosh Shilimkar <santosh.shilimkar@ti.com>
> >> Date: Fri, 30 Mar 2012 12:43:29 +0530
> >> Subject: [PATCH] ARM: OMAP: Make OMAP clocksource source selection runtime.
> >>
> >> Current OMAP code support couple of clocksource options based on compilation
> >> flag. The 32KHz based sync timer and a gptimer based clock source which can
> >> run on 32KHz or system clock (e.g 38.4 MHz). So there can be 3 options.
> >>
> >> 1. 32KHz synctimer
> >> 2. Sysclock based(e.g 38.4 MHz) gptimer
> >> 3. 32KHz based gptimer.
> >>
> >> The optional gptimer based clocksource was added so that it can give the
> >> high precision than synctimer so expected usage was 2 and not 3. Unfortunatlly
> >> option 2, clocksource doesn't meet the requirement of free-running clock
> >> as per clocksource need. It stops in low power states when  sysclock is cut.
> >> That makes gptimer based clocksource option useless for OMAP2/3/4 devices
> >> with sysclock as a clock input. Option 3 will still work but it is no better'
> >> than 32K synctimer based clocksource.
> >>
> >> So ideally we can kill the gptimer based clocksource option but there are some
> >> OMAP based derivative SoCs like AMXXXX which doesn't have synictimer hardware IP
> >> and need to fallback on 32KHz based gptimer clocksource.
> >>
> >> Considering above, make synctimer and gptimer clocksource runtime
> >> selectable so that both OMAP and AMXXXX continue to use the same code.
> >>
> >> Not-yet-signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> >> ---
> >>  arch/arm/mach-omap2/timer.c |   25 ++++++++-----------------
> >>  1 files changed, 8 insertions(+), 17 deletions(-)
> >>
> >> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
> >> index c512bac..3878e59 100644
> >> --- a/arch/arm/mach-omap2/timer.c
> >> +++ b/arch/arm/mach-omap2/timer.c
> >> @@ -234,21 +234,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
> >>  }
> >>
> >>  /* Clocksource code */
> >> -
> >> -#ifdef CONFIG_OMAP_32K_TIMER
> >> -/*
> >> - * When 32k-timer is enabled, don't use GPTimer for clocksource
> >> - * instead, just leave default clocksource which uses the 32k
> >> - * sync counter.  See clocksource setup in plat-omap/counter_32k.c
> >> - */
> >> -
> >> -static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
> >> -{
> >> -	omap_init_clocksource_32k();
> >> -}
> >> -
> >> -#else
> >> -
> >>  static struct omap_dm_timer clksrc;
> >>
> >>  /*
> >> @@ -276,7 +261,7 @@ static u32 notrace dmtimer_read_sched_clock(void)
> >>  }
> >>
> >>  /* Setup free-running counter for clocksource */
> >> -static void __init omap2_gp_clocksource_init(int gptimer_id,
> >> +static void __init omap2_gptimer_clocksource_init(int gptimer_id,
> >>  						const char *fck_source)
> >>  {
> >>  	int res;
> >> @@ -295,7 +280,13 @@ static void __init omap2_gp_clocksource_init(int
> >> gptimer_id,
> >>  		pr_err("Could not register clocksource %s\n",
> >>  			clocksource_gpt.name);
> >>  }
> >> -#endif
> >> +
> >> +static void __init omap2_gp_clocksource_init(int gptimer_id,
> >> +                                                const char *fck_source)
> >> +{
> >> +	if (omap_init_clocksource_32k())
> >> +		omap2_gptimer_clocksource_init(gptimer_id, fck_source);
> >> +}
> >>
> > 
> > With this patch, will you be able to choose gptimer as a clocksource
> > using bootparameter (or sysfs) for given kernel uImage?
> > 
> Why do you want that ? Look at changelog. The gptimer based clocksource
> is useless for OMAP and for AM devices synctimer is not available.
> 
> 
> > The answer is simply NO...as the registration of gptimer is based on
> > failure from omap_init_clocksource_32k(). And this is nothing different 
> > than my original patch, my patch exactly does same thing.
> > 
> I ight have missed your original patch. If that patch is similar then
> no problems.
> 
> > The requirement after 'ming Lie' response on my patch was, there will be
> > usecases where we might need to use gptimer for clocksource and with 
> > the patch it is not possible, since you will only register 
> > 32k_counter here.
> > 
> I think Ming Lie might have expected that gptimer clocksource might
> be better which is not the case.
> 
> > So in order to allow user to choose between 32K and gptimer, you must 
> > register both and make 32k as a default thing.
> > 
> As described in the commit log, its not needed at all. Let's not add
> a feature which is just useless because the gptimer based clock
> source has no advantage against the syntimer.
> 

I completely agree with you, and that is my understanding too.

After Ming Lie's comment, the point that I came to my mind was,
certainly there will be resolution difference between these two clocksources,
if  gptimer2 is sourced from sys_ck (26Mhz).

I am quite not sure, whether will there be any practical usecase where you
change the kernel clocksource for high resolution dynamically through sysfs 
or something. May be not....but still it is possible.


In that case my original patch still holds good here. I would still request
you to review the same and give your acked-by  or tested-by.


Thanks,
Vaibhav 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
>> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
>> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:

[....]

>> >
>> > With this patch, will you be able to choose gptimer as a clocksource
>> > using bootparameter (or sysfs) for given kernel uImage?
>> >
>> Why do you want that ? Look at changelog. The gptimer based clocksource
>> is useless for OMAP and for AM devices synctimer is not available.
>>
>>
>> > The answer is simply NO...as the registration of gptimer is based on
>> > failure from omap_init_clocksource_32k(). And this is nothing different
>> > than my original patch, my patch exactly does same thing.
>> >
>> I ight have missed your original patch. If that patch is similar then
>> no problems.
>>
>> > The requirement after 'ming Lie' response on my patch was, there will be
>> > usecases where we might need to use gptimer for clocksource and with
>> > the patch it is not possible, since you will only register
>> > 32k_counter here.
>> >
>> I think Ming Lie might have expected that gptimer clocksource might
>> be better which is not the case.
>>
>> > So in order to allow user to choose between 32K and gptimer, you must
>> > register both and make 32k as a default thing.
>> >
>> As described in the commit log, its not needed at all. Let's not add
>> a feature which is just useless because the gptimer based clock
>> source has no advantage against the syntimer.
>>
>
> I completely agree with you, and that is my understanding too.
>
Thanks !!

> After Ming Lie's comment, the point that I came to my mind was,
> certainly there will be resolution difference between these two clocksources,
> if  gptimer2 is sourced from sys_ck (26Mhz).
>
GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
and when sysclock is cut, it stops.

> I am quite not sure, whether will there be any practical usecase where you
> change the kernel clocksource for high resolution dynamically through sysfs
> or something. May be not....but still it is possible.
>
Even if there is a usecase, there no option with full PM.

>
> In that case my original patch still holds good here. I would still request
> you to review the same and give your acked-by  or tested-by.
>
I just looked at that.
It looks fine to me. Can you repost that patch addressing Kevin and
Tony's comments.
Also update the change log as describe in the patch i posted.

Once that done, will ack it.

Regards
Santosh
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
>> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
>> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:

[....]

>> >
>> > With this patch, will you be able to choose gptimer as a clocksource
>> > using bootparameter (or sysfs) for given kernel uImage?
>> >
>> Why do you want that ? Look at changelog. The gptimer based clocksource
>> is useless for OMAP and for AM devices synctimer is not available.
>>
>>
>> > The answer is simply NO...as the registration of gptimer is based on
>> > failure from omap_init_clocksource_32k(). And this is nothing different
>> > than my original patch, my patch exactly does same thing.
>> >
>> I ight have missed your original patch. If that patch is similar then
>> no problems.
>>
>> > The requirement after 'ming Lie' response on my patch was, there will be
>> > usecases where we might need to use gptimer for clocksource and with
>> > the patch it is not possible, since you will only register
>> > 32k_counter here.
>> >
>> I think Ming Lie might have expected that gptimer clocksource might
>> be better which is not the case.
>>
>> > So in order to allow user to choose between 32K and gptimer, you must
>> > register both and make 32k as a default thing.
>> >
>> As described in the commit log, its not needed at all. Let's not add
>> a feature which is just useless because the gptimer based clock
>> source has no advantage against the syntimer.
>>
>
> I completely agree with you, and that is my understanding too.
>
Thanks !!

> After Ming Lie's comment, the point that I came to my mind was,
> certainly there will be resolution difference between these two clocksources,
> if ?gptimer2 is sourced from sys_ck (26Mhz).
>
GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
and when sysclock is cut, it stops.

> I am quite not sure, whether will there be any practical usecase where you
> change the kernel clocksource for high resolution dynamically through sysfs
> or something. May be not....but still it is possible.
>
Even if there is a usecase, there no option with full PM.

>
> In that case my original patch still holds good here. I would still request
> you to review the same and give your acked-by ?or tested-by.
>
I just looked at that.
It looks fine to me. Can you repost that patch addressing Kevin and
Tony's comments.
Also update the change log as describe in the patch i posted.

Once that done, will ack it.

Regards
Santosh

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 30, 2012 at 14:50:02, Shilimkar, Santosh wrote:
> On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
> >> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
> >> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
> 
> [....]
> 
> >> >
> >> > With this patch, will you be able to choose gptimer as a clocksource
> >> > using bootparameter (or sysfs) for given kernel uImage?
> >> >
> >> Why do you want that ? Look at changelog. The gptimer based clocksource
> >> is useless for OMAP and for AM devices synctimer is not available.
> >>
> >>
> >> > The answer is simply NO...as the registration of gptimer is based on
> >> > failure from omap_init_clocksource_32k(). And this is nothing different
> >> > than my original patch, my patch exactly does same thing.
> >> >
> >> I ight have missed your original patch. If that patch is similar then
> >> no problems.
> >>
> >> > The requirement after 'ming Lie' response on my patch was, there will be
> >> > usecases where we might need to use gptimer for clocksource and with
> >> > the patch it is not possible, since you will only register
> >> > 32k_counter here.
> >> >
> >> I think Ming Lie might have expected that gptimer clocksource might
> >> be better which is not the case.
> >>
> >> > So in order to allow user to choose between 32K and gptimer, you must
> >> > register both and make 32k as a default thing.
> >> >
> >> As described in the commit log, its not needed at all. Let's not add
> >> a feature which is just useless because the gptimer based clock
> >> source has no advantage against the syntimer.
> >>
> >
> > I completely agree with you, and that is my understanding too.
> >
> Thanks !!
> 
> > After Ming Lie's comment, the point that I came to my mind was,
> > certainly there will be resolution difference between these two clocksources,
> > if  gptimer2 is sourced from sys_ck (26Mhz).
> >
> GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
> and when sysclock is cut, it stops.
> 
> > I am quite not sure, whether will there be any practical usecase where you
> > change the kernel clocksource for high resolution dynamically through sysfs
> > or something. May be not....but still it is possible.
> >
> Even if there is a usecase, there no option with full PM.
> 

What if before suspending the system, you switch back to 32k_counter 
everytime, and in resume you again switch to gp_timer?

Please consider this as just a technical discussion, as I am myself quite 
not sure whether we have such use-case available.

> >
> > In that case my original patch still holds good here. I would still request
> > you to review the same and give your acked-by  or tested-by.
> >
> I just looked at that.
> It looks fine to me. Can you repost that patch addressing Kevin and
> Tony's comments.
> Also update the change log as describe in the patch i posted.
> 
> Once that done, will ack it.
> 

Thanks for the review and discussion, I will submit revised version shortly.


Thanks,
Vaibhav

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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 30, 2012 at 14:50:02, Shilimkar, Santosh wrote:
> On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
> >> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
> >> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
> 
> [....]
> 
> >> >
> >> > With this patch, will you be able to choose gptimer as a clocksource
> >> > using bootparameter (or sysfs) for given kernel uImage?
> >> >
> >> Why do you want that ? Look at changelog. The gptimer based clocksource
> >> is useless for OMAP and for AM devices synctimer is not available.
> >>
> >>
> >> > The answer is simply NO...as the registration of gptimer is based on
> >> > failure from omap_init_clocksource_32k(). And this is nothing different
> >> > than my original patch, my patch exactly does same thing.
> >> >
> >> I ight have missed your original patch. If that patch is similar then
> >> no problems.
> >>
> >> > The requirement after 'ming Lie' response on my patch was, there will be
> >> > usecases where we might need to use gptimer for clocksource and with
> >> > the patch it is not possible, since you will only register
> >> > 32k_counter here.
> >> >
> >> I think Ming Lie might have expected that gptimer clocksource might
> >> be better which is not the case.
> >>
> >> > So in order to allow user to choose between 32K and gptimer, you must
> >> > register both and make 32k as a default thing.
> >> >
> >> As described in the commit log, its not needed at all. Let's not add
> >> a feature which is just useless because the gptimer based clock
> >> source has no advantage against the syntimer.
> >>
> >
> > I completely agree with you, and that is my understanding too.
> >
> Thanks !!
> 
> > After Ming Lie's comment, the point that I came to my mind was,
> > certainly there will be resolution difference between these two clocksources,
> > if ?gptimer2 is sourced from sys_ck (26Mhz).
> >
> GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
> and when sysclock is cut, it stops.
> 
> > I am quite not sure, whether will there be any practical usecase where you
> > change the kernel clocksource for high resolution dynamically through sysfs
> > or something. May be not....but still it is possible.
> >
> Even if there is a usecase, there no option with full PM.
> 

What if before suspending the system, you switch back to 32k_counter 
everytime, and in resume you again switch to gp_timer?

Please consider this as just a technical discussion, as I am myself quite 
not sure whether we have such use-case available.

> >
> > In that case my original patch still holds good here. I would still request
> > you to review the same and give your acked-by ?or tested-by.
> >
> I just looked at that.
> It looks fine to me. Can you repost that patch addressing Kevin and
> Tony's comments.
> Also update the change log as describe in the patch i posted.
> 
> Once that done, will ack it.
> 

Thanks for the review and discussion, I will submit revised version shortly.


Thanks,
Vaibhav

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Fri, Mar 30, 2012 at 2:58 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Fri, Mar 30, 2012 at 14:50:02, Shilimkar, Santosh wrote:
>> On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> > On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
>> >> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
>> >> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
>>
>> [....]
>>
>> >> >
>> >> > With this patch, will you be able to choose gptimer as a clocksource
>> >> > using bootparameter (or sysfs) for given kernel uImage?
>> >> >
>> >> Why do you want that ? Look at changelog. The gptimer based clocksource
>> >> is useless for OMAP and for AM devices synctimer is not available.
>> >>
>> >>
>> >> > The answer is simply NO...as the registration of gptimer is based on
>> >> > failure from omap_init_clocksource_32k(). And this is nothing different
>> >> > than my original patch, my patch exactly does same thing.
>> >> >
>> >> I ight have missed your original patch. If that patch is similar then
>> >> no problems.
>> >>
>> >> > The requirement after 'ming Lie' response on my patch was, there will be
>> >> > usecases where we might need to use gptimer for clocksource and with
>> >> > the patch it is not possible, since you will only register
>> >> > 32k_counter here.
>> >> >
>> >> I think Ming Lie might have expected that gptimer clocksource might
>> >> be better which is not the case.
>> >>
>> >> > So in order to allow user to choose between 32K and gptimer, you must
>> >> > register both and make 32k as a default thing.
>> >> >
>> >> As described in the commit log, its not needed at all. Let's not add
>> >> a feature which is just useless because the gptimer based clock
>> >> source has no advantage against the syntimer.
>> >>
>> >
>> > I completely agree with you, and that is my understanding too.
>> >
>> Thanks !!
>>
>> > After Ming Lie's comment, the point that I came to my mind was,
>> > certainly there will be resolution difference between these two clocksources,
>> > if  gptimer2 is sourced from sys_ck (26Mhz).
>> >
>> GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
>> and when sysclock is cut, it stops.
>>
>> > I am quite not sure, whether will there be any practical usecase where you
>> > change the kernel clocksource for high resolution dynamically through sysfs
>> > or something. May be not....but still it is possible.
>> >
>> Even if there is a usecase, there no option with full PM.
>>
>
> What if before suspending the system, you switch back to 32k_counter
> everytime, and in resume you again switch to gp_timer?
>
This has been discussed at length. Dynamic switching between
clock-sources affects the NTP time corrections. Go through [1]
when you have time, since its a long thread.

If and when that feature works, we can update the clocksource
code.

Regards
Santosh

[1]  https://lkml.org/lkml/2011/6/2/167
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Fri, Mar 30, 2012 at 2:58 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Fri, Mar 30, 2012 at 14:50:02, Shilimkar, Santosh wrote:
>> On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> > On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
>> >> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
>> >> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
>>
>> [....]
>>
>> >> >
>> >> > With this patch, will you be able to choose gptimer as a clocksource
>> >> > using bootparameter (or sysfs) for given kernel uImage?
>> >> >
>> >> Why do you want that ? Look at changelog. The gptimer based clocksource
>> >> is useless for OMAP and for AM devices synctimer is not available.
>> >>
>> >>
>> >> > The answer is simply NO...as the registration of gptimer is based on
>> >> > failure from omap_init_clocksource_32k(). And this is nothing different
>> >> > than my original patch, my patch exactly does same thing.
>> >> >
>> >> I ight have missed your original patch. If that patch is similar then
>> >> no problems.
>> >>
>> >> > The requirement after 'ming Lie' response on my patch was, there will be
>> >> > usecases where we might need to use gptimer for clocksource and with
>> >> > the patch it is not possible, since you will only register
>> >> > 32k_counter here.
>> >> >
>> >> I think Ming Lie might have expected that gptimer clocksource might
>> >> be better which is not the case.
>> >>
>> >> > So in order to allow user to choose between 32K and gptimer, you must
>> >> > register both and make 32k as a default thing.
>> >> >
>> >> As described in the commit log, its not needed at all. Let's not add
>> >> a feature which is just useless because the gptimer based clock
>> >> source has no advantage against the syntimer.
>> >>
>> >
>> > I completely agree with you, and that is my understanding too.
>> >
>> Thanks !!
>>
>> > After Ming Lie's comment, the point that I came to my mind was,
>> > certainly there will be resolution difference between these two clocksources,
>> > if ?gptimer2 is sourced from sys_ck (26Mhz).
>> >
>> GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
>> and when sysclock is cut, it stops.
>>
>> > I am quite not sure, whether will there be any practical usecase where you
>> > change the kernel clocksource for high resolution dynamically through sysfs
>> > or something. May be not....but still it is possible.
>> >
>> Even if there is a usecase, there no option with full PM.
>>
>
> What if before suspending the system, you switch back to 32k_counter
> everytime, and in resume you again switch to gp_timer?
>
This has been discussed at length. Dynamic switching between
clock-sources affects the NTP time corrections. Go through [1]
when you have time, since its a long thread.

If and when that feature works, we can update the clocksource
code.

Regards
Santosh

[1]  https://lkml.org/lkml/2011/6/2/167

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 30, 2012 at 15:12:19, Shilimkar, Santosh wrote:
> On Fri, Mar 30, 2012 at 2:58 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Fri, Mar 30, 2012 at 14:50:02, Shilimkar, Santosh wrote:
> >> On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> > On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
> >> >> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
> >> >> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
> >>
<...>

Santosh & others,

Do you think, it makes sense to clean up the CONFIG_OMAP_32K_TIMER
usage in mach-omap2/timer.c file now? Specifically below code-snippet -

#ifdef CONFIG_OMAP_32K_TIMER
#define OMAP2_CLKEV_SOURCE      OMAP2_32K_SOURCE
#define OMAP3_CLKEV_SOURCE      OMAP3_32K_SOURCE
#define OMAP4_CLKEV_SOURCE      OMAP4_32K_SOURCE
#define OMAP3_SECURE_TIMER      12
#else
#define OMAP2_CLKEV_SOURCE      OMAP2_MPU_SOURCE
#define OMAP3_CLKEV_SOURCE      OMAP3_MPU_SOURCE
#define OMAP4_CLKEV_SOURCE      OMAP4_MPU_SOURCE
#define OMAP3_SECURE_TIMER      1
#endif

And lets make 32k_fclk as default clocksource for gptimer, if it is being
used as clocksource. Atleast with this I can clean whole omap2/3/4 families,
and I can take omap1 thing later .
(as I have to understand/read about omap1 first).

If you agree, I can include this cleanup also in my next version of patch-
series. What's your opinion here?

Thanks,
Vaibhav

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Mar 30, 2012 at 15:12:19, Shilimkar, Santosh wrote:
> On Fri, Mar 30, 2012 at 2:58 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Fri, Mar 30, 2012 at 14:50:02, Shilimkar, Santosh wrote:
> >> On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> >> > On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
> >> >> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
> >> >> > On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
> >>
<...>

Santosh & others,

Do you think, it makes sense to clean up the CONFIG_OMAP_32K_TIMER
usage in mach-omap2/timer.c file now? Specifically below code-snippet -

#ifdef CONFIG_OMAP_32K_TIMER
#define OMAP2_CLKEV_SOURCE      OMAP2_32K_SOURCE
#define OMAP3_CLKEV_SOURCE      OMAP3_32K_SOURCE
#define OMAP4_CLKEV_SOURCE      OMAP4_32K_SOURCE
#define OMAP3_SECURE_TIMER      12
#else
#define OMAP2_CLKEV_SOURCE      OMAP2_MPU_SOURCE
#define OMAP3_CLKEV_SOURCE      OMAP3_MPU_SOURCE
#define OMAP4_CLKEV_SOURCE      OMAP4_MPU_SOURCE
#define OMAP3_SECURE_TIMER      1
#endif

And lets make 32k_fclk as default clocksource for gptimer, if it is being
used as clocksource. Atleast with this I can clean whole omap2/3/4 families,
and I can take omap1 thing later .
(as I have to understand/read about omap1 first).

If you agree, I can include this cleanup also in my next version of patch-
series. What's your opinion here?

Thanks,
Vaibhav

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Friday 30 March 2012 04:59 PM, Hiremath, Vaibhav wrote:
> On Fri, Mar 30, 2012 at 15:12:19, Shilimkar, Santosh wrote:
>> On Fri, Mar 30, 2012 at 2:58 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>> On Fri, Mar 30, 2012 at 14:50:02, Shilimkar, Santosh wrote:
>>>> On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>> On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
>>>>>> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
>>>>>>> On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
>>>>
> <...>
> 
> Santosh & others,
> 
> Do you think, it makes sense to clean up the CONFIG_OMAP_32K_TIMER
> usage in mach-omap2/timer.c file now? Specifically below code-snippet -
> 
> #ifdef CONFIG_OMAP_32K_TIMER
> #define OMAP2_CLKEV_SOURCE      OMAP2_32K_SOURCE
> #define OMAP3_CLKEV_SOURCE      OMAP3_32K_SOURCE
> #define OMAP4_CLKEV_SOURCE      OMAP4_32K_SOURCE
> #define OMAP3_SECURE_TIMER      12
> #else
> #define OMAP2_CLKEV_SOURCE      OMAP2_MPU_SOURCE
> #define OMAP3_CLKEV_SOURCE      OMAP3_MPU_SOURCE
> #define OMAP4_CLKEV_SOURCE      OMAP4_MPU_SOURCE
> #define OMAP3_SECURE_TIMER      1
> #endif
> 
> And lets make 32k_fclk as default clocksource for gptimer, if it is being
> used as clocksource. Atleast with this I can clean whole omap2/3/4 families,
> and I can take omap1 thing later .
> (as I have to understand/read about omap1 first).
> 
> If you agree, I can include this cleanup also in my next version of patch-
> series. What's your opinion here?
> 
I am ok with this clean up. But I let Tony take decision on it.

Regards
Santosh

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Friday 30 March 2012 04:59 PM, Hiremath, Vaibhav wrote:
> On Fri, Mar 30, 2012 at 15:12:19, Shilimkar, Santosh wrote:
>> On Fri, Mar 30, 2012 at 2:58 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>> On Fri, Mar 30, 2012 at 14:50:02, Shilimkar, Santosh wrote:
>>>> On Fri, Mar 30, 2012 at 2:42 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>>>>> On Fri, Mar 30, 2012 at 14:08:20, Shilimkar, Santosh wrote:
>>>>>> On Friday 30 March 2012 02:02 PM, Hiremath, Vaibhav wrote:
>>>>>>> On Fri, Mar 30, 2012 at 13:11:35, Shilimkar, Santosh wrote:
>>>>
> <...>
> 
> Santosh & others,
> 
> Do you think, it makes sense to clean up the CONFIG_OMAP_32K_TIMER
> usage in mach-omap2/timer.c file now? Specifically below code-snippet -
> 
> #ifdef CONFIG_OMAP_32K_TIMER
> #define OMAP2_CLKEV_SOURCE      OMAP2_32K_SOURCE
> #define OMAP3_CLKEV_SOURCE      OMAP3_32K_SOURCE
> #define OMAP4_CLKEV_SOURCE      OMAP4_32K_SOURCE
> #define OMAP3_SECURE_TIMER      12
> #else
> #define OMAP2_CLKEV_SOURCE      OMAP2_MPU_SOURCE
> #define OMAP3_CLKEV_SOURCE      OMAP3_MPU_SOURCE
> #define OMAP4_CLKEV_SOURCE      OMAP4_MPU_SOURCE
> #define OMAP3_SECURE_TIMER      1
> #endif
> 
> And lets make 32k_fclk as default clocksource for gptimer, if it is being
> used as clocksource. Atleast with this I can clean whole omap2/3/4 families,
> and I can take omap1 thing later .
> (as I have to understand/read about omap1 first).
> 
> If you agree, I can include this cleanup also in my next version of patch-
> series. What's your opinion here?
> 
I am ok with this clean up. But I let Tony take decision on it.

Regards
Santosh

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Fri, Mar 30, 2012 at 5:20 PM, Shilimkar, Santosh <santosh.shilimkar@ti.com>
>
>> After Ming Lie's comment, the point that I came to my mind was,
>> certainly there will be resolution difference between these two clocksources,
>> if  gptimer2 is sourced from sys_ck (26Mhz).
>>
> GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
> and when sysclock is cut, it stops.

If neither CONFIG_PM or CONFIG_CPUIDLE is set, GPTIMER2 with sysclock
should be an option.

As I commented before, high resolution timer is very useful for trace, debug or
high frequency perf sample. Suppose you want to trace the running time of
one function,  32K counter can only give you a resolution of ~35us, which is
too coarse to work well.


Thanks,
-- 
Ming Lei

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Fri, Mar 30, 2012 at 5:20 PM, Shilimkar, Santosh <santosh.shilimkar@ti.com>
>
>> After Ming Lie's comment, the point that I came to my mind was,
>> certainly there will be resolution difference between these two clocksources,
>> if ?gptimer2 is sourced from sys_ck (26Mhz).
>>
> GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
> and when sysclock is cut, it stops.

If neither CONFIG_PM or CONFIG_CPUIDLE is set, GPTIMER2 with sysclock
should be an option.

As I commented before, high resolution timer is very useful for trace, debug or
high frequency perf sample. Suppose you want to trace the running time of
one function,  32K counter can only give you a resolution of ~35us, which is
too coarse to work well.


Thanks,
-- 
Ming Lei

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Sat, Mar 31, 2012 at 7:00 AM, Ming Lei <tom.leiming@gmail.com> wrote:
> On Fri, Mar 30, 2012 at 5:20 PM, Shilimkar, Santosh <santosh.shilimkar@ti.com>
>>
>>> After Ming Lie's comment, the point that I came to my mind was,
>>> certainly there will be resolution difference between these two clocksources,
>>> if  gptimer2 is sourced from sys_ck (26Mhz).
>>>
>> GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
>> and when sysclock is cut, it stops.
>
> If neither CONFIG_PM or CONFIG_CPUIDLE is set, GPTIMER2 with sysclock
> should be an option.
>
So it's a PM disable kernel and you will recompile it.

> As I commented before, high resolution timer is very useful for trace, debug or
> high frequency perf sample. Suppose you want to trace the running time of
> one function,  32K counter can only give you a resolution of ~35us, which is
> too coarse to work well.
>
Since you need to recompile the kernel, you can very much tweak the
clocksource to use GPTIMER with sysl clock. Support for that is still
in place.

Regards
Santosh
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Sat, Mar 31, 2012 at 7:00 AM, Ming Lei <tom.leiming@gmail.com> wrote:
> On Fri, Mar 30, 2012 at 5:20 PM, Shilimkar, Santosh <santosh.shilimkar@ti.com>
>>
>>> After Ming Lie's comment, the point that I came to my mind was,
>>> certainly there will be resolution difference between these two clocksources,
>>> if ?gptimer2 is sourced from sys_ck (26Mhz).
>>>
>> GPTIMER2 with sysclock is not an option. GPTIMER is not in wakeup domain
>> and when sysclock is cut, it stops.
>
> If neither CONFIG_PM or CONFIG_CPUIDLE is set, GPTIMER2 with sysclock
> should be an option.
>
So it's a PM disable kernel and you will recompile it.

> As I commented before, high resolution timer is very useful for trace, debug or
> high frequency perf sample. Suppose you want to trace the running time of
> one function, ?32K counter can only give you a resolution of ~35us, which is
> too coarse to work well.
>
Since you need to recompile the kernel, you can very much tweak the
clocksource to use GPTIMER with sysl clock. Support for that is still
in place.

Regards
Santosh

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Sat, Mar 31, 2012 at 2:30 PM, Shilimkar, Santosh
> Since you need to recompile the kernel, you can very much tweak the
> clocksource to use GPTIMER with sysl clock. Support for that is still
> in place.

With current kernel, running 'make menuconfig' can do it, but after applying
Hiremath's patch[1], I have to edit the source code manually to get it, so looks
this kind of tweaking is not friendly enough, :-(

[1], http://marc.info/?l=linux-arm-kernel&m=133311647410324&w=2

Thanks,
-- 
Ming Lei

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Sat, Mar 31, 2012 at 2:30 PM, Shilimkar, Santosh
> Since you need to recompile the kernel, you can very much tweak the
> clocksource to use GPTIMER with sysl clock. Support for that is still
> in place.

With current kernel, running 'make menuconfig' can do it, but after applying
Hiremath's patch[1], I have to edit the source code manually to get it, so looks
this kind of tweaking is not friendly enough, :-(

[1], http://marc.info/?l=linux-arm-kernel&m=133311647410324&w=2

Thanks,
-- 
Ming Lei

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Sat, Mar 31, 2012 at 2:09 PM, Ming Lei <tom.leiming@gmail.com> wrote:
> On Sat, Mar 31, 2012 at 2:30 PM, Shilimkar, Santosh
>> Since you need to recompile the kernel, you can very much tweak the
>> clocksource to use GPTIMER with sysl clock. Support for that is still
>> in place.
>
> With current kernel, running 'make menuconfig' can do it, but after applying
> Hiremath's patch[1], I have to edit the source code manually to get it, so looks
> this kind of tweaking is not friendly enough, :-(
>
It's not friendly but doable. But above can be supported I guess.

Since you are talking about doing menuconfig
and rebuilding kernel so what can be done is when one disable CPUIDLE
and PM, one can disabled 32K source as well. And then 32K clocksource
init should fail and fallback on gptimer clock source.

Vaibhav,
Can you update your patch to support above. The patch which I
did was doing exactly that but was not using hwmod. The problem with your
patch is synctimer hwmod lookup on OMAP will never fail if the hwmod
entry is supported.

So you might better use failure case of omap_init_clocksource_32k() for
fall back on gptimer source as I tried in my patch. That should support
the usage mentioned by Ming Lie

Regards
Santosh

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Sat, Mar 31, 2012 at 2:09 PM, Ming Lei <tom.leiming@gmail.com> wrote:
> On Sat, Mar 31, 2012 at 2:30 PM, Shilimkar, Santosh
>> Since you need to recompile the kernel, you can very much tweak the
>> clocksource to use GPTIMER with sysl clock. Support for that is still
>> in place.
>
> With current kernel, running 'make menuconfig' can do it, but after applying
> Hiremath's patch[1], I have to edit the source code manually to get it, so looks
> this kind of tweaking is not friendly enough, :-(
>
It's not friendly but doable. But above can be supported I guess.

Since you are talking about doing menuconfig
and rebuilding kernel so what can be done is when one disable CPUIDLE
and PM, one can disabled 32K source as well. And then 32K clocksource
init should fail and fallback on gptimer clock source.

Vaibhav,
Can you update your patch to support above. The patch which I
did was doing exactly that but was not using hwmod. The problem with your
patch is synctimer hwmod lookup on OMAP will never fail if the hwmod
entry is supported.

So you might better use failure case of omap_init_clocksource_32k() for
fall back on gptimer source as I tried in my patch. That should support
the usage mentioned by Ming Lie

Regards
Santosh

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Sun, Apr 1, 2012 at 3:10 AM, Shilimkar, Santosh
<santosh.shilimkar@ti.com> wrote:
> On Sat, Mar 31, 2012 at 2:09 PM, Ming Lei <tom.leiming@gmail.com> wrote:
>> On Sat, Mar 31, 2012 at 2:30 PM, Shilimkar, Santosh
>>> Since you need to recompile the kernel, you can very much tweak the
>>> clocksource to use GPTIMER with sysl clock. Support for that is still
>>> in place.
>>
>> With current kernel, running 'make menuconfig' can do it, but after applying
>> Hiremath's patch[1], I have to edit the source code manually to get it, so looks
>> this kind of tweaking is not friendly enough, :-(
>>
> It's not friendly but doable. But above can be supported I guess.
>
> Since you are talking about doing menuconfig
> and rebuilding kernel so what can be done is when one disable CPUIDLE
> and PM, one can disabled 32K source as well. And then 32K clocksource
> init should fail and fallback on gptimer clock source.

OK, it should work, but looks OMAP_32K_TIMER option has to be kept
for the usage, which may be a bit divergent to the purpose of the patch set.

So how about introducing a kernel parameter to decide if bypassing
32K source and using gptimer source directly, and let which depend
on PM?

>
> Vaibhav,
> Can you update your patch to support above. The patch which I
> did was doing exactly that but was not using hwmod. The problem with your
> patch is synctimer hwmod lookup on OMAP will never fail if the hwmod
> entry is supported.
>
> So you might better use failure case of omap_init_clocksource_32k() for
> fall back on gptimer source as I tried in my patch. That should support

You patch still doesn't work for the usage because you removed 32K option.


Thanks,
-- 
Ming Lei

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Sun, Apr 1, 2012 at 3:10 AM, Shilimkar, Santosh
<santosh.shilimkar@ti.com> wrote:
> On Sat, Mar 31, 2012 at 2:09 PM, Ming Lei <tom.leiming@gmail.com> wrote:
>> On Sat, Mar 31, 2012 at 2:30 PM, Shilimkar, Santosh
>>> Since you need to recompile the kernel, you can very much tweak the
>>> clocksource to use GPTIMER with sysl clock. Support for that is still
>>> in place.
>>
>> With current kernel, running 'make menuconfig' can do it, but after applying
>> Hiremath's patch[1], I have to edit the source code manually to get it, so looks
>> this kind of tweaking is not friendly enough, :-(
>>
> It's not friendly but doable. But above can be supported I guess.
>
> Since you are talking about doing menuconfig
> and rebuilding kernel so what can be done is when one disable CPUIDLE
> and PM, one can disabled 32K source as well. And then 32K clocksource
> init should fail and fallback on gptimer clock source.

OK, it should work, but looks OMAP_32K_TIMER option has to be kept
for the usage, which may be a bit divergent to the purpose of the patch set.

So how about introducing a kernel parameter to decide if bypassing
32K source and using gptimer source directly, and let which depend
on PM?

>
> Vaibhav,
> Can you update your patch to support above. The patch which I
> did was doing exactly that but was not using hwmod. The problem with your
> patch is synctimer hwmod lookup on OMAP will never fail if the hwmod
> entry is supported.
>
> So you might better use failure case of omap_init_clocksource_32k() for
> fall back on gptimer source as I tried in my patch. That should support

You patch still doesn't work for the usage because you removed 32K option.


Thanks,
-- 
Ming Lei

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Sun, Apr 1, 2012 at 7:09 AM, Ming Lei <tom.leiming@gmail.com> wrote:
> On Sun, Apr 1, 2012 at 3:10 AM, Shilimkar, Santosh
> <santosh.shilimkar@ti.com> wrote:
>> On Sat, Mar 31, 2012 at 2:09 PM, Ming Lei <tom.leiming@gmail.com> wrote:
>>> On Sat, Mar 31, 2012 at 2:30 PM, Shilimkar, Santosh
>>>> Since you need to recompile the kernel, you can very much tweak the
>>>> clocksource to use GPTIMER with sysl clock. Support for that is still
>>>> in place.
>>>
>>> With current kernel, running 'make menuconfig' can do it, but after applying
>>> Hiremath's patch[1], I have to edit the source code manually to get it, so looks
>>> this kind of tweaking is not friendly enough, :-(
>>>
>> It's not friendly but doable. But above can be supported I guess.
>>
>> Since you are talking about doing menuconfig
>> and rebuilding kernel so what can be done is when one disable CPUIDLE
>> and PM, one can disabled 32K source as well. And then 32K clocksource
>> init should fail and fallback on gptimer clock source.
>
> OK, it should work, but looks OMAP_32K_TIMER option has to be kept
> for the usage, which may be a bit divergent to the purpose of the patch set.
>
> So how about introducing a kernel parameter to decide if bypassing
> 32K source and using gptimer source directly, and let which depend
> on PM?
>
We are just doing circles on this patch set. Till the dynamic clock-soucre
switching supported for low power entry exit, the high precision clocksoucre
selection is already broken and very much limited for use

I don't personally like to add features which hardly anybody use and
fundamentally
broken with full kernel.

I let Tony take final call on what's appropriate.

Regards
Santosh

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Sun, Apr 1, 2012 at 7:09 AM, Ming Lei <tom.leiming@gmail.com> wrote:
> On Sun, Apr 1, 2012 at 3:10 AM, Shilimkar, Santosh
> <santosh.shilimkar@ti.com> wrote:
>> On Sat, Mar 31, 2012 at 2:09 PM, Ming Lei <tom.leiming@gmail.com> wrote:
>>> On Sat, Mar 31, 2012 at 2:30 PM, Shilimkar, Santosh
>>>> Since you need to recompile the kernel, you can very much tweak the
>>>> clocksource to use GPTIMER with sysl clock. Support for that is still
>>>> in place.
>>>
>>> With current kernel, running 'make menuconfig' can do it, but after applying
>>> Hiremath's patch[1], I have to edit the source code manually to get it, so looks
>>> this kind of tweaking is not friendly enough, :-(
>>>
>> It's not friendly but doable. But above can be supported I guess.
>>
>> Since you are talking about doing menuconfig
>> and rebuilding kernel so what can be done is when one disable CPUIDLE
>> and PM, one can disabled 32K source as well. And then 32K clocksource
>> init should fail and fallback on gptimer clock source.
>
> OK, it should work, but looks OMAP_32K_TIMER option has to be kept
> for the usage, which may be a bit divergent to the purpose of the patch set.
>
> So how about introducing a kernel parameter to decide if bypassing
> 32K source and using gptimer source directly, and let which depend
> on PM?
>
We are just doing circles on this patch set. Till the dynamic clock-soucre
switching supported for low power entry exit, the high precision clocksoucre
selection is already broken and very much limited for use

I don't personally like to add features which hardly anybody use and
fundamentally
broken with full kernel.

I let Tony take final call on what's appropriate.

Regards
Santosh

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

"Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:

[...]

> I don't personally like to add features which hardly anybody use and
> fundamentally broken with full kernel.

Let's keep sane defaults, but not make it unreasonable to tweak eaither.

I suggest what has already been mentioned.

Register both timers, but have the sync timer have a higher rating.  On
AMxxx where there is no sync timer, GPtimer will be used.

For those who want to use GPtimer, they can boot using clocksource= to
override the default.

Santosh is right, GPtimer will not work on a PM enabled kernel, but
there are lots of ways to use the cmdline to get a non-working kernel,
so that's OK by me.

Let's just ensure that the boot-defaults are sane.

Kevin

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

"Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:

[...]

> I don't personally like to add features which hardly anybody use and
> fundamentally broken with full kernel.

Let's keep sane defaults, but not make it unreasonable to tweak eaither.

I suggest what has already been mentioned.

Register both timers, but have the sync timer have a higher rating.  On
AMxxx where there is no sync timer, GPtimer will be used.

For those who want to use GPtimer, they can boot using clocksource= to
override the default.

Santosh is right, GPtimer will not work on a PM enabled kernel, but
there are lots of ways to use the cmdline to get a non-working kernel,
so that's OK by me.

Let's just ensure that the boot-defaults are sane.

Kevin

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Tue, Apr 3, 2012 at 12:05 AM, Kevin Hilman <khilman@ti.com> wrote:
> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
>
> [...]
>
>> I don't personally like to add features which hardly anybody use and
>> fundamentally broken with full kernel.
>
> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
>
Exactly. Thanks for echoing the concern.

> I suggest what has already been mentioned.
>
> Register both timers, but have the sync timer have a higher rating.  On
> AMxxx where there is no sync timer, GPtimer will be used.
>
Technically it's a hack just from clock precision point of view but I don't mind
this.

> For those who want to use GPtimer, they can boot using clocksource= to
> override the default.
>
Sounds good to me.

> Santosh is right, GPtimer will not work on a PM enabled kernel, but
> there are lots of ways to use the cmdline to get a non-working kernel,
> so that's OK by me.
>
> Let's just ensure that the boot-defaults are sane.
>
Absolutely.

Regards
Santosh
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Tue, Apr 3, 2012 at 12:05 AM, Kevin Hilman <khilman@ti.com> wrote:
> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
>
> [...]
>
>> I don't personally like to add features which hardly anybody use and
>> fundamentally broken with full kernel.
>
> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
>
Exactly. Thanks for echoing the concern.

> I suggest what has already been mentioned.
>
> Register both timers, but have the sync timer have a higher rating. ?On
> AMxxx where there is no sync timer, GPtimer will be used.
>
Technically it's a hack just from clock precision point of view but I don't mind
this.

> For those who want to use GPtimer, they can boot using clocksource= to
> override the default.
>
Sounds good to me.

> Santosh is right, GPtimer will not work on a PM enabled kernel, but
> there are lots of ways to use the cmdline to get a non-working kernel,
> so that's OK by me.
>
> Let's just ensure that the boot-defaults are sane.
>
Absolutely.

Regards
Santosh

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Apr 03, 2012 at 00:05:38, Hilman, Kevin wrote:
> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
> 
> [...]
> 
> > I don't personally like to add features which hardly anybody use and
> > fundamentally broken with full kernel.
> 
> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
> 
> I suggest what has already been mentioned.
> 
> Register both timers, but have the sync timer have a higher rating.  On
> AMxxx where there is no sync timer, GPtimer will be used.
> 

This is another good option, I can change the rating of both the timers.
With below description and given understanding/discussion/usability of both
the timers, we can reverse the rating,

32K-sync counter = 300
GPTIMER = 250

Considering the fact that, 32k-sync counter is more usable than gptimer on
OMAP platform.


@"include/linux/clocksource.h"

* @rating:             rating value for selection (higher is better)
*                      To avoid rating inflation the following
*                      list should give you a guide as to how
*                      to assign your clocksource a rating
*                      1-99: Unfit for real use
*                             Only available for bootup and testing purposes.
*                      100-199: Base level usability.
*                              Functional for real use, but not desired.
*                      200-299: Good.
*                              A correct and usable clocksource.
*                      300-399: Desired.
*                              A reasonably fast and accurate clocksource.
*                      400-499: Perfect
*                              The ideal clocksource. A must-use where
*                              available.


Thanks,
Vaibhav

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Apr 03, 2012 at 00:05:38, Hilman, Kevin wrote:
> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
> 
> [...]
> 
> > I don't personally like to add features which hardly anybody use and
> > fundamentally broken with full kernel.
> 
> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
> 
> I suggest what has already been mentioned.
> 
> Register both timers, but have the sync timer have a higher rating.  On
> AMxxx where there is no sync timer, GPtimer will be used.
> 

This is another good option, I can change the rating of both the timers.
With below description and given understanding/discussion/usability of both
the timers, we can reverse the rating,

32K-sync counter = 300
GPTIMER = 250

Considering the fact that, 32k-sync counter is more usable than gptimer on
OMAP platform.


@"include/linux/clocksource.h"

* @rating:             rating value for selection (higher is better)
*                      To avoid rating inflation the following
*                      list should give you a guide as to how
*                      to assign your clocksource a rating
*                      1-99: Unfit for real use
*                             Only available for bootup and testing purposes.
*                      100-199: Base level usability.
*                              Functional for real use, but not desired.
*                      200-299: Good.
*                              A correct and usable clocksource.
*                      300-399: Desired.
*                              A reasonably fast and accurate clocksource.
*                      400-499: Perfect
*                              The ideal clocksource. A must-use where
*                              available.


Thanks,
Vaibhav

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Tue, Apr 3, 2012 at 9:05 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Tue, Apr 03, 2012 at 00:05:38, Hilman, Kevin wrote:
>> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
>>
>> [...]
>>
>> > I don't personally like to add features which hardly anybody use and
>> > fundamentally broken with full kernel.
>>
>> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
>>
>> I suggest what has already been mentioned.
>>
>> Register both timers, but have the sync timer have a higher rating.  On
>> AMxxx where there is no sync timer, GPtimer will be used.
>>
>
> This is another good option, I can change the rating of both the timers.
> With below description and given understanding/discussion/usability of both
> the timers, we can reverse the rating,
>
Btw, if we are going with this path, then there won't any need of commandline
option since clock-source can be switched from user space as well.

Regards
santosh
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Tue, Apr 3, 2012 at 9:05 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Tue, Apr 03, 2012 at 00:05:38, Hilman, Kevin wrote:
>> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
>>
>> [...]
>>
>> > I don't personally like to add features which hardly anybody use and
>> > fundamentally broken with full kernel.
>>
>> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
>>
>> I suggest what has already been mentioned.
>>
>> Register both timers, but have the sync timer have a higher rating. ?On
>> AMxxx where there is no sync timer, GPtimer will be used.
>>
>
> This is another good option, I can change the rating of both the timers.
> With below description and given understanding/discussion/usability of both
> the timers, we can reverse the rating,
>
Btw, if we are going with this path, then there won't any need of commandline
option since clock-source can be switched from user space as well.

Regards
santosh

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Apr 04, 2012 at 14:34:09, Shilimkar, Santosh wrote:
> On Tue, Apr 3, 2012 at 9:05 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Tue, Apr 03, 2012 at 00:05:38, Hilman, Kevin wrote:
> >> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
> >>
> >> [...]
> >>
> >> > I don't personally like to add features which hardly anybody use and
> >> > fundamentally broken with full kernel.
> >>
> >> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
> >>
> >> I suggest what has already been mentioned.
> >>
> >> Register both timers, but have the sync timer have a higher rating.  On
> >> AMxxx where there is no sync timer, GPtimer will be used.
> >>
> >
> > This is another good option, I can change the rating of both the timers.
> > With below description and given understanding/discussion/usability of both
> > the timers, we can reverse the rating,
> >
> Btw, if we are going with this path, then there won't any need of commandline
> option since clock-source can be switched from user space as well.
> 

Yes, both the options will be open now and its upto user how he want to 
choose it (either bootargs or sysfs).

Thanks,
Vaibhav
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Apr 04, 2012 at 14:34:09, Shilimkar, Santosh wrote:
> On Tue, Apr 3, 2012 at 9:05 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > On Tue, Apr 03, 2012 at 00:05:38, Hilman, Kevin wrote:
> >> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
> >>
> >> [...]
> >>
> >> > I don't personally like to add features which hardly anybody use and
> >> > fundamentally broken with full kernel.
> >>
> >> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
> >>
> >> I suggest what has already been mentioned.
> >>
> >> Register both timers, but have the sync timer have a higher rating. ?On
> >> AMxxx where there is no sync timer, GPtimer will be used.
> >>
> >
> > This is another good option, I can change the rating of both the timers.
> > With below description and given understanding/discussion/usability of both
> > the timers, we can reverse the rating,
> >
> Btw, if we are going with this path, then there won't any need of commandline
> option since clock-source can be switched from user space as well.
> 

Yes, both the options will be open now and its upto user how he want to 
choose it (either bootargs or sysfs).

Thanks,
Vaibhav

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Apr 04, 2012 at 16:09:51, Hiremath, Vaibhav wrote:
> On Wed, Apr 04, 2012 at 14:34:09, Shilimkar, Santosh wrote:
> > On Tue, Apr 3, 2012 at 9:05 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > > On Tue, Apr 03, 2012 at 00:05:38, Hilman, Kevin wrote:
> > >> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
> > >>
> > >> [...]
> > >>
> > >> > I don't personally like to add features which hardly anybody use and
> > >> > fundamentally broken with full kernel.
> > >>
> > >> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
> > >>
> > >> I suggest what has already been mentioned.
> > >>
> > >> Register both timers, but have the sync timer have a higher rating.  On
> > >> AMxxx where there is no sync timer, GPtimer will be used.
> > >>
> > >
> > > This is another good option, I can change the rating of both the timers.
> > > With below description and given understanding/discussion/usability of both
> > > the timers, we can reverse the rating,
> > >
> > Btw, if we are going with this path, then there won't any need of commandline
> > option since clock-source can be switched from user space as well.
> > 
> 
> Yes, both the options will be open now and its upto user how he want to 
> choose it (either bootargs or sysfs).
> 

Santosh, Kevin and others (may be Russell can comment/conform),

Unfortunately, I am still struggling to get final patch out of this 
discussion,

Although now we concluded on changing the rates for 32ksync (rating = 300) 
and gptmier (rating = 250), and we thought kernel will choose better 
clocksource automatically, in default case it would be 32ksync_counter, and 
that is what we want; and user can use bootargs to override the clocksource 
to gptimer.

But we all missed on "setup_sched_clock()", which is dependent on clock 
Frequency, and based on that whole sched_clock() function works.

In case of 32ksync_counter:
--------------------------
cd.mult - 4000000000, cd.shift - 17
sched_clock: 32 bits at 32kHz, resolution 30517ns, wraps every 131071999ms

In case of gptimer:
--------------------------
cd.mult - 2581110154, cd.shift - 26
sched_clock: 32 bits at 26MHz, resolution 38ns, wraps every 165191ms

Also, in addition to this,

 - We do not have any API available in sched_clock code to update the 
   mult/shift factors.

 - You supposed to not call setup_sched_clock() multiple times, it dumps 
   whole stack with,

   WARN_ON(read_sched_clock != jiffy_sched_clock_read);

 - In case, user pass "clocksource="gp timer" in bootargs, still initially
   Kernel is going to use 32ksync_counter as a clocksource and the late in 
   the boot sequence it will switch to gptimer.

   [    0.637512] Switching to clocksource gp timer


There seems to be limitation for ARM architecture, it is restricted by
sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
Natively, clocksource framework does support change in rate/frequency for
registered timer, using,

   - __clocksource_updatefreq_scale()
   - __clocksource_updatefreq_hz()
   - __clocksource_updatefreq_khz()


May be I am missing something here, so far this is what my understanding is, 
I am still digging through the code to understand how best we can handle 
this. And also, I wouldn't want to again create our own sched_clock 
interface.

May be Russell can help me to conform my understanding here.


Coming back to our actual problem of registering 2 clocksources, with all 
above things, I am slowly moving towards keeping CONFIG_OMAP_32K_TIMER 
config option and use compile time option for this (original approach) along 
with hwmod detection, so that it can be reused for devices like AM33xx.

Code implementation will be,

#ifdef CONFIG_OMAP_32K_TIMER
	oh = omap_hwmod_lookup(oh_name);
	if (oh && oh->slaves_cnt != 0) {
		u32 pbase;
		unsigned long size;
		struct resource mem_rsrc;
	
		res = omap_hwmod_get_resource_byname(oh, IORESOURCE_MEM,
					NULL, &mem_rsrc);
		if (!res) {
			pbase = mem_rsrc.start + 0x10;
			size = mem_rsrc.end - mem_rsrc.start;
			res = omap_init_clocksource_32k(pbase, size);
			if (!res)
				return;
	}
}
#endif

	/* Fall back to gp-timer code */
	res = omap_dm_timer_init_one(&clksrc, gptimer_id, fck_source);
	BUG_ON(res);

	__omap_dm_timer_load_start(&clksrc,
			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);

	setup_sched_clock(dmtimer_read_sched_clock, 32, clksrc.rate);

	if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
		pr_err("Could not register clocksource %s\n",
						clocksource_gpt.name);
	else
		pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
						gptimer_id, clksrc.rate);


Thanks,
Vaibhav

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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Wed, Apr 04, 2012 at 16:09:51, Hiremath, Vaibhav wrote:
> On Wed, Apr 04, 2012 at 14:34:09, Shilimkar, Santosh wrote:
> > On Tue, Apr 3, 2012 at 9:05 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> > > On Tue, Apr 03, 2012 at 00:05:38, Hilman, Kevin wrote:
> > >> "Shilimkar, Santosh" <santosh.shilimkar@ti.com> writes:
> > >>
> > >> [...]
> > >>
> > >> > I don't personally like to add features which hardly anybody use and
> > >> > fundamentally broken with full kernel.
> > >>
> > >> Let's keep sane defaults, but not make it unreasonable to tweak eaither.
> > >>
> > >> I suggest what has already been mentioned.
> > >>
> > >> Register both timers, but have the sync timer have a higher rating. ?On
> > >> AMxxx where there is no sync timer, GPtimer will be used.
> > >>
> > >
> > > This is another good option, I can change the rating of both the timers.
> > > With below description and given understanding/discussion/usability of both
> > > the timers, we can reverse the rating,
> > >
> > Btw, if we are going with this path, then there won't any need of commandline
> > option since clock-source can be switched from user space as well.
> > 
> 
> Yes, both the options will be open now and its upto user how he want to 
> choose it (either bootargs or sysfs).
> 

Santosh, Kevin and others (may be Russell can comment/conform),

Unfortunately, I am still struggling to get final patch out of this 
discussion,

Although now we concluded on changing the rates for 32ksync (rating = 300) 
and gptmier (rating = 250), and we thought kernel will choose better 
clocksource automatically, in default case it would be 32ksync_counter, and 
that is what we want; and user can use bootargs to override the clocksource 
to gptimer.

But we all missed on "setup_sched_clock()", which is dependent on clock 
Frequency, and based on that whole sched_clock() function works.

In case of 32ksync_counter:
--------------------------
cd.mult - 4000000000, cd.shift - 17
sched_clock: 32 bits at 32kHz, resolution 30517ns, wraps every 131071999ms

In case of gptimer:
--------------------------
cd.mult - 2581110154, cd.shift - 26
sched_clock: 32 bits at 26MHz, resolution 38ns, wraps every 165191ms

Also, in addition to this,

 - We do not have any API available in sched_clock code to update the 
   mult/shift factors.

 - You supposed to not call setup_sched_clock() multiple times, it dumps 
   whole stack with,

   WARN_ON(read_sched_clock != jiffy_sched_clock_read);

 - In case, user pass "clocksource="gp timer" in bootargs, still initially
   Kernel is going to use 32ksync_counter as a clocksource and the late in 
   the boot sequence it will switch to gptimer.

   [    0.637512] Switching to clocksource gp timer


There seems to be limitation for ARM architecture, it is restricted by
sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
Natively, clocksource framework does support change in rate/frequency for
registered timer, using,

   - __clocksource_updatefreq_scale()
   - __clocksource_updatefreq_hz()
   - __clocksource_updatefreq_khz()


May be I am missing something here, so far this is what my understanding is, 
I am still digging through the code to understand how best we can handle 
this. And also, I wouldn't want to again create our own sched_clock 
interface.

May be Russell can help me to conform my understanding here.


Coming back to our actual problem of registering 2 clocksources, with all 
above things, I am slowly moving towards keeping CONFIG_OMAP_32K_TIMER 
config option and use compile time option for this (original approach) along 
with hwmod detection, so that it can be reused for devices like AM33xx.

Code implementation will be,

#ifdef CONFIG_OMAP_32K_TIMER
	oh = omap_hwmod_lookup(oh_name);
	if (oh && oh->slaves_cnt != 0) {
		u32 pbase;
		unsigned long size;
		struct resource mem_rsrc;
	
		res = omap_hwmod_get_resource_byname(oh, IORESOURCE_MEM,
					NULL, &mem_rsrc);
		if (!res) {
			pbase = mem_rsrc.start + 0x10;
			size = mem_rsrc.end - mem_rsrc.start;
			res = omap_init_clocksource_32k(pbase, size);
			if (!res)
				return;
	}
}
#endif

	/* Fall back to gp-timer code */
	res = omap_dm_timer_init_one(&clksrc, gptimer_id, fck_source);
	BUG_ON(res);

	__omap_dm_timer_load_start(&clksrc,
			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);

	setup_sched_clock(dmtimer_read_sched_clock, 32, clksrc.rate);

	if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
		pr_err("Could not register clocksource %s\n",
						clocksource_gpt.name);
	else
		pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
						gptimer_id, clksrc.rate);


Thanks,
Vaibhav

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Russell King - ARM Linux]

On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
> There seems to be limitation for ARM architecture, it is restricted by
> sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
> Natively, clocksource framework does support change in rate/frequency for
> registered timer, using,

Any kind of switching of timing sources introduces loss of time issues
by the mere fact that you can't instantly know the counter values of
both timing sources at precisely the same instant - because CPUs can
only do one thing at a time.  So any kind of repeated dynamic switching
_will_ result in a gradual loss of time - which will be indeterminant
as it depends on the frequency of the switching and the relative delta
between the two.

To put it another way - it is not possible to maintain high precision
and accuracy while dynamically switching your timing sources.

I'm not about to lift the restriction that there's only one source for
sched_clock() just for OMAP.  That'd require a lot of additional code -
it's not just about adjusting the multiplier and shift, you also have to
correct the returned ns value as well, which means synchronizing against
two counters.  (And as I've pointed out above, that's impossible to do
accurately.)

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Russell King - ARM Linux]

On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
> There seems to be limitation for ARM architecture, it is restricted by
> sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
> Natively, clocksource framework does support change in rate/frequency for
> registered timer, using,

Any kind of switching of timing sources introduces loss of time issues
by the mere fact that you can't instantly know the counter values of
both timing sources at precisely the same instant - because CPUs can
only do one thing at a time.  So any kind of repeated dynamic switching
_will_ result in a gradual loss of time - which will be indeterminant
as it depends on the frequency of the switching and the relative delta
between the two.

To put it another way - it is not possible to maintain high precision
and accuracy while dynamically switching your timing sources.

I'm not about to lift the restriction that there's only one source for
sched_clock() just for OMAP.  That'd require a lot of additional code -
it's not just about adjusting the multiplier and shift, you also have to
correct the returned ns value as well, which means synchronizing against
two counters.  (And as I've pointed out above, that's impossible to do
accurately.)

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Thu, Apr 05, 2012 at 15:22:21, Russell King - ARM Linux wrote:
> On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
> > There seems to be limitation for ARM architecture, it is restricted by
> > sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
> > Natively, clocksource framework does support change in rate/frequency for
> > registered timer, using,
> 
> Any kind of switching of timing sources introduces loss of time issues
> by the mere fact that you can't instantly know the counter values of
> both timing sources at precisely the same instant - because CPUs can
> only do one thing at a time.  So any kind of repeated dynamic switching
> _will_ result in a gradual loss of time - which will be indeterminant
> as it depends on the frequency of the switching and the relative delta
> between the two.
> 
> To put it another way - it is not possible to maintain high precision
> and accuracy while dynamically switching your timing sources.
> 
> I'm not about to lift the restriction that there's only one source for
> sched_clock() just for OMAP.  That'd require a lot of additional code -
> it's not just about adjusting the multiplier and shift, you also have to
> correct the returned ns value as well, which means synchronizing against
> two counters.  (And as I've pointed out above, that's impossible to do
> accurately.)
> 

Thanks a ton Russell for confirming on this,

I understand, we also have to adjust ns value and such confirmation is what exactly I was looking for.

So this means, we have to use compile time option, as existing
implementation in "arch/arm/mach-omap2/timer.c".

Thanks again, I will repost patches shortly with the code changes (mentioned 
in my last email)

Thanks,
Vaibhav

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Thu, Apr 05, 2012 at 15:22:21, Russell King - ARM Linux wrote:
> On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
> > There seems to be limitation for ARM architecture, it is restricted by
> > sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
> > Natively, clocksource framework does support change in rate/frequency for
> > registered timer, using,
> 
> Any kind of switching of timing sources introduces loss of time issues
> by the mere fact that you can't instantly know the counter values of
> both timing sources at precisely the same instant - because CPUs can
> only do one thing at a time.  So any kind of repeated dynamic switching
> _will_ result in a gradual loss of time - which will be indeterminant
> as it depends on the frequency of the switching and the relative delta
> between the two.
> 
> To put it another way - it is not possible to maintain high precision
> and accuracy while dynamically switching your timing sources.
> 
> I'm not about to lift the restriction that there's only one source for
> sched_clock() just for OMAP.  That'd require a lot of additional code -
> it's not just about adjusting the multiplier and shift, you also have to
> correct the returned ns value as well, which means synchronizing against
> two counters.  (And as I've pointed out above, that's impossible to do
> accurately.)
> 

Thanks a ton Russell for confirming on this,

I understand, we also have to adjust ns value and such confirmation is what exactly I was looking for.

So this means, we have to use compile time option, as existing
implementation in "arch/arm/mach-omap2/timer.c".

Thanks again, I will repost patches shortly with the code changes (mentioned 
in my last email)

Thanks,
Vaibhav

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Thursday 05 April 2012 04:01 PM, Hiremath, Vaibhav wrote:
> On Thu, Apr 05, 2012 at 15:22:21, Russell King - ARM Linux wrote:
>> On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
>>> There seems to be limitation for ARM architecture, it is restricted by
>>> sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
>>> Natively, clocksource framework does support change in rate/frequency for
>>> registered timer, using,
>>
>> Any kind of switching of timing sources introduces loss of time issues
>> by the mere fact that you can't instantly know the counter values of
>> both timing sources at precisely the same instant - because CPUs can
>> only do one thing at a time.  So any kind of repeated dynamic switching
>> _will_ result in a gradual loss of time - which will be indeterminant
>> as it depends on the frequency of the switching and the relative delta
>> between the two.
>>
>> To put it another way - it is not possible to maintain high precision
>> and accuracy while dynamically switching your timing sources.
>>
>> I'm not about to lift the restriction that there's only one source for
>> sched_clock() just for OMAP.  That'd require a lot of additional code -
>> it's not just about adjusting the multiplier and shift, you also have to
>> correct the returned ns value as well, which means synchronizing against
>> two counters.  (And as I've pointed out above, that's impossible to do
>> accurately.)
>>
> 
> Thanks a ton Russell for confirming on this,
> 
> I understand, we also have to adjust ns value and such confirmation is what exactly I was looking for.
> 
> So this means, we have to use compile time option, as existing
> implementation in "arch/arm/mach-omap2/timer.c".
> 
> Thanks again, I will repost patches shortly with the code changes (mentioned 
> in my last email)
> 
I suggest you wait for Kevin and Tony to look at it.

Am still going back to what I proposed initially.
Why not the conditional way as shown in the patch [1] I proposed or
your initial patch with some updates?  Something like this.

if(commandline.clksource == gpt)
	omap2_gptimer_clocksource_init(gptimer_id, fck_source);
else if (omap_init_clocksource_32k())
	omap2_gptimer_clocksource_init(gptimer_id, fck_source);

This won't need compile time option and gives you all everybody wants.

1. Ability to use gpt as a clock-source for perf like stuff
2. Hardware like AMXX where 32K synctimer doesn't exist which means
omap_init_clocksource_32k() will fail and use gptimer.
3. For OMAP, it will continue to use 32K sync timer.

What am I missing Vaibhav?

Regards
Santosh

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Thursday 05 April 2012 04:01 PM, Hiremath, Vaibhav wrote:
> On Thu, Apr 05, 2012 at 15:22:21, Russell King - ARM Linux wrote:
>> On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
>>> There seems to be limitation for ARM architecture, it is restricted by
>>> sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
>>> Natively, clocksource framework does support change in rate/frequency for
>>> registered timer, using,
>>
>> Any kind of switching of timing sources introduces loss of time issues
>> by the mere fact that you can't instantly know the counter values of
>> both timing sources at precisely the same instant - because CPUs can
>> only do one thing at a time.  So any kind of repeated dynamic switching
>> _will_ result in a gradual loss of time - which will be indeterminant
>> as it depends on the frequency of the switching and the relative delta
>> between the two.
>>
>> To put it another way - it is not possible to maintain high precision
>> and accuracy while dynamically switching your timing sources.
>>
>> I'm not about to lift the restriction that there's only one source for
>> sched_clock() just for OMAP.  That'd require a lot of additional code -
>> it's not just about adjusting the multiplier and shift, you also have to
>> correct the returned ns value as well, which means synchronizing against
>> two counters.  (And as I've pointed out above, that's impossible to do
>> accurately.)
>>
> 
> Thanks a ton Russell for confirming on this,
> 
> I understand, we also have to adjust ns value and such confirmation is what exactly I was looking for.
> 
> So this means, we have to use compile time option, as existing
> implementation in "arch/arm/mach-omap2/timer.c".
> 
> Thanks again, I will repost patches shortly with the code changes (mentioned 
> in my last email)
> 
I suggest you wait for Kevin and Tony to look at it.

Am still going back to what I proposed initially.
Why not the conditional way as shown in the patch [1] I proposed or
your initial patch with some updates?  Something like this.

if(commandline.clksource == gpt)
	omap2_gptimer_clocksource_init(gptimer_id, fck_source);
else if (omap_init_clocksource_32k())
	omap2_gptimer_clocksource_init(gptimer_id, fck_source);

This won't need compile time option and gives you all everybody wants.

1. Ability to use gpt as a clock-source for perf like stuff
2. Hardware like AMXX where 32K synctimer doesn't exist which means
omap_init_clocksource_32k() will fail and use gptimer.
3. For OMAP, it will continue to use 32K sync timer.

What am I missing Vaibhav?

Regards
Santosh

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

"Hiremath, Vaibhav" <hvaibhav@ti.com> writes:

> On Thu, Apr 05, 2012 at 15:22:21, Russell King - ARM Linux wrote:
>> On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
>> > There seems to be limitation for ARM architecture, it is restricted by
>> > sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
>> > Natively, clocksource framework does support change in rate/frequency for
>> > registered timer, using,
>> 
>> Any kind of switching of timing sources introduces loss of time issues
>> by the mere fact that you can't instantly know the counter values of
>> both timing sources at precisely the same instant - because CPUs can
>> only do one thing at a time.  So any kind of repeated dynamic switching
>> _will_ result in a gradual loss of time - which will be indeterminant
>> as it depends on the frequency of the switching and the relative delta
>> between the two.
>> 
>> To put it another way - it is not possible to maintain high precision
>> and accuracy while dynamically switching your timing sources.
>> 
>> I'm not about to lift the restriction that there's only one source for
>> sched_clock() just for OMAP.  That'd require a lot of additional code -
>> it's not just about adjusting the multiplier and shift, you also have to
>> correct the returned ns value as well, which means synchronizing against
>> two counters.  (And as I've pointed out above, that's impossible to do
>> accurately.)
>> 
>
> Thanks a ton Russell for confirming on this,
>
> I understand, we also have to adjust ns value and such confirmation is what exactly I was looking for.
>
> So this means, we have to use compile time option, as existing
> implementation in "arch/arm/mach-omap2/timer.c".

Not exactly.  A compile time option isn't (yet) the only option.

Russell points out the various problems with dynamic switching of
clocksources, which is true.  However, we're not trying to dynamically
switch clocksources.

What we need is only one-time selection at boot based on presence (or
not) of various timers.  IOW, we still only ever need to call
setup_sched_clock() once based on which HW timers are available.

Why not just delay the setup_sched_clock() until the clocksource is
decided?

Kevin

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

"Hiremath, Vaibhav" <hvaibhav@ti.com> writes:

> On Thu, Apr 05, 2012 at 15:22:21, Russell King - ARM Linux wrote:
>> On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
>> > There seems to be limitation for ARM architecture, it is restricted by
>> > sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
>> > Natively, clocksource framework does support change in rate/frequency for
>> > registered timer, using,
>> 
>> Any kind of switching of timing sources introduces loss of time issues
>> by the mere fact that you can't instantly know the counter values of
>> both timing sources at precisely the same instant - because CPUs can
>> only do one thing at a time.  So any kind of repeated dynamic switching
>> _will_ result in a gradual loss of time - which will be indeterminant
>> as it depends on the frequency of the switching and the relative delta
>> between the two.
>> 
>> To put it another way - it is not possible to maintain high precision
>> and accuracy while dynamically switching your timing sources.
>> 
>> I'm not about to lift the restriction that there's only one source for
>> sched_clock() just for OMAP.  That'd require a lot of additional code -
>> it's not just about adjusting the multiplier and shift, you also have to
>> correct the returned ns value as well, which means synchronizing against
>> two counters.  (And as I've pointed out above, that's impossible to do
>> accurately.)
>> 
>
> Thanks a ton Russell for confirming on this,
>
> I understand, we also have to adjust ns value and such confirmation is what exactly I was looking for.
>
> So this means, we have to use compile time option, as existing
> implementation in "arch/arm/mach-omap2/timer.c".

Not exactly.  A compile time option isn't (yet) the only option.

Russell points out the various problems with dynamic switching of
clocksources, which is true.  However, we're not trying to dynamically
switch clocksources.

What we need is only one-time selection at boot based on presence (or
not) of various timers.  IOW, we still only ever need to call
setup_sched_clock() once based on which HW timers are available.

Why not just delay the setup_sched_clock() until the clocksource is
decided?

Kevin

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Apr 06, 2012 at 03:03:01, Hilman, Kevin wrote:
> "Hiremath, Vaibhav" <hvaibhav@ti.com> writes:
> 
> > On Thu, Apr 05, 2012 at 15:22:21, Russell King - ARM Linux wrote:
> >> On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
> >> > There seems to be limitation for ARM architecture, it is restricted by
> >> > sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
> >> > Natively, clocksource framework does support change in rate/frequency for
> >> > registered timer, using,
> >> 
> >> Any kind of switching of timing sources introduces loss of time issues
> >> by the mere fact that you can't instantly know the counter values of
> >> both timing sources at precisely the same instant - because CPUs can
> >> only do one thing at a time.  So any kind of repeated dynamic switching
> >> _will_ result in a gradual loss of time - which will be indeterminant
> >> as it depends on the frequency of the switching and the relative delta
> >> between the two.
> >> 
> >> To put it another way - it is not possible to maintain high precision
> >> and accuracy while dynamically switching your timing sources.
> >> 
> >> I'm not about to lift the restriction that there's only one source for
> >> sched_clock() just for OMAP.  That'd require a lot of additional code -
> >> it's not just about adjusting the multiplier and shift, you also have to
> >> correct the returned ns value as well, which means synchronizing against
> >> two counters.  (And as I've pointed out above, that's impossible to do
> >> accurately.)
> >> 
> >
> > Thanks a ton Russell for confirming on this,
> >
> > I understand, we also have to adjust ns value and such confirmation is what exactly I was looking for.
> >
> > So this means, we have to use compile time option, as existing
> > implementation in "arch/arm/mach-omap2/timer.c".
> 
> Not exactly.  A compile time option isn't (yet) the only option.
> 
> Russell points out the various problems with dynamic switching of
> clocksources, which is true.  However, we're not trying to dynamically
> switch clocksources.
> 
> What we need is only one-time selection at boot based on presence (or
> not) of various timers.  IOW, we still only ever need to call
> setup_sched_clock() once based on which HW timers are available.
> 
> Why not just delay the setup_sched_clock() until the clocksource is
> decided?
> 

Kevin,

I liked Santosh's idea in using command line argument "clocksource=" and 
make decision based on this. I have implemented it and tried it on both
OMAP3EVM and beaglebone and it works great.

I have introduced something like this in mach-omap2/timer.c,

static int __init omap2_override_clocksource(char* str)
{
	if (!str)
		return 0;
	/*
	 * For OMAP architecture, we only have two options
	 *    - sync_32k (default)
	 *    - gp timer
	 */
	if (!strcmp(str, "gp timer"))
		use_gptimer_clksrc = true;

	return 0;
}
early_param("clocksource", omap2_override_clocksource);


It solves all issues what we have been trying address.

Thanks,

Vaibhav

> Kevin
> 

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Apr 06, 2012 at 03:03:01, Hilman, Kevin wrote:
> "Hiremath, Vaibhav" <hvaibhav@ti.com> writes:
> 
> > On Thu, Apr 05, 2012 at 15:22:21, Russell King - ARM Linux wrote:
> >> On Thu, Apr 05, 2012 at 09:36:00AM +0000, Hiremath, Vaibhav wrote:
> >> > There seems to be limitation for ARM architecture, it is restricted by
> >> > sched_clock implementation present in "arch/arm/kernel/sched_clock.c".
> >> > Natively, clocksource framework does support change in rate/frequency for
> >> > registered timer, using,
> >> 
> >> Any kind of switching of timing sources introduces loss of time issues
> >> by the mere fact that you can't instantly know the counter values of
> >> both timing sources at precisely the same instant - because CPUs can
> >> only do one thing at a time.  So any kind of repeated dynamic switching
> >> _will_ result in a gradual loss of time - which will be indeterminant
> >> as it depends on the frequency of the switching and the relative delta
> >> between the two.
> >> 
> >> To put it another way - it is not possible to maintain high precision
> >> and accuracy while dynamically switching your timing sources.
> >> 
> >> I'm not about to lift the restriction that there's only one source for
> >> sched_clock() just for OMAP.  That'd require a lot of additional code -
> >> it's not just about adjusting the multiplier and shift, you also have to
> >> correct the returned ns value as well, which means synchronizing against
> >> two counters.  (And as I've pointed out above, that's impossible to do
> >> accurately.)
> >> 
> >
> > Thanks a ton Russell for confirming on this,
> >
> > I understand, we also have to adjust ns value and such confirmation is what exactly I was looking for.
> >
> > So this means, we have to use compile time option, as existing
> > implementation in "arch/arm/mach-omap2/timer.c".
> 
> Not exactly.  A compile time option isn't (yet) the only option.
> 
> Russell points out the various problems with dynamic switching of
> clocksources, which is true.  However, we're not trying to dynamically
> switch clocksources.
> 
> What we need is only one-time selection at boot based on presence (or
> not) of various timers.  IOW, we still only ever need to call
> setup_sched_clock() once based on which HW timers are available.
> 
> Why not just delay the setup_sched_clock() until the clocksource is
> decided?
> 

Kevin,

I liked Santosh's idea in using command line argument "clocksource=" and 
make decision based on this. I have implemented it and tried it on both
OMAP3EVM and beaglebone and it works great.

I have introduced something like this in mach-omap2/timer.c,

static int __init omap2_override_clocksource(char* str)
{
	if (!str)
		return 0;
	/*
	 * For OMAP architecture, we only have two options
	 *    - sync_32k (default)
	 *    - gp timer
	 */
	if (!strcmp(str, "gp timer"))
		use_gptimer_clksrc = true;

	return 0;
}
early_param("clocksource", omap2_override_clocksource);


It solves all issues what we have been trying address.

Thanks,

Vaibhav

> Kevin
> 

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Tony Lindgren]

* Hiremath, Vaibhav <hvaibhav@ti.com> [120405 22:25]:
> On Fri, Apr 06, 2012 at 03:03:01, Hilman, Kevin wrote:
> > 
> > What we need is only one-time selection at boot based on presence (or
> > not) of various timers.  IOW, we still only ever need to call
> > setup_sched_clock() once based on which HW timers are available.
> > 
> > Why not just delay the setup_sched_clock() until the clocksource is
> > decided?

I think that's we're already doing for omap1 as 15xx does not
have the 32 KiHz timer and the CONFIG_OMAP_32K_TIMER is no longer
conflicting with the MPU timer.

> I liked Santosh's idea in using command line argument "clocksource=" and 
> make decision based on this. I have implemented it and tried it on both
> OMAP3EVM and beaglebone and it works great.
> 
> I have introduced something like this in mach-omap2/timer.c,
> 
> static int __init omap2_override_clocksource(char* str)
> {
> 	if (!str)
> 		return 0;
> 	/*
> 	 * For OMAP architecture, we only have two options
> 	 *    - sync_32k (default)
> 	 *    - gp timer
> 	 */
> 	if (!strcmp(str, "gp timer"))
> 		use_gptimer_clksrc = true;
> 
> 	return 0;
> }
> early_param("clocksource", omap2_override_clocksource);

Sure a cmdline override is nice to have for user selection.
But we should also by default do the right thing based on what the
board wants in .timer entry. 
 
> It solves all issues what we have been trying address.

I'm a bit confused.. Can you briefly summarize again what all
issues you're having? Just want to select a different clocksource
for beaglebone? If you don't have the 32 KiHz then that can't
be selected naturally?

Regards,

Tony

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Tony Lindgren]

* Hiremath, Vaibhav <hvaibhav@ti.com> [120405 22:25]:
> On Fri, Apr 06, 2012 at 03:03:01, Hilman, Kevin wrote:
> > 
> > What we need is only one-time selection at boot based on presence (or
> > not) of various timers.  IOW, we still only ever need to call
> > setup_sched_clock() once based on which HW timers are available.
> > 
> > Why not just delay the setup_sched_clock() until the clocksource is
> > decided?

I think that's we're already doing for omap1 as 15xx does not
have the 32 KiHz timer and the CONFIG_OMAP_32K_TIMER is no longer
conflicting with the MPU timer.

> I liked Santosh's idea in using command line argument "clocksource=" and 
> make decision based on this. I have implemented it and tried it on both
> OMAP3EVM and beaglebone and it works great.
> 
> I have introduced something like this in mach-omap2/timer.c,
> 
> static int __init omap2_override_clocksource(char* str)
> {
> 	if (!str)
> 		return 0;
> 	/*
> 	 * For OMAP architecture, we only have two options
> 	 *    - sync_32k (default)
> 	 *    - gp timer
> 	 */
> 	if (!strcmp(str, "gp timer"))
> 		use_gptimer_clksrc = true;
> 
> 	return 0;
> }
> early_param("clocksource", omap2_override_clocksource);

Sure a cmdline override is nice to have for user selection.
But we should also by default do the right thing based on what the
board wants in .timer entry. 
 
> It solves all issues what we have been trying address.

I'm a bit confused.. Can you briefly summarize again what all
issues you're having? Just want to select a different clocksource
for beaglebone? If you don't have the 32 KiHz then that can't
be selected naturally?

Regards,

Tony

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

"Hiremath, Vaibhav" <hvaibhav@ti.com> writes:

[...]

> I liked Santosh's idea in using command line argument "clocksource=" and 
> make decision based on this. I have implemented it and tried it on both
> OMAP3EVM and beaglebone and it works great.
>
> I have introduced something like this in mach-omap2/timer.c,
>
> static int __init omap2_override_clocksource(char* str)
> {
> 	if (!str)
> 		return 0;
> 	/*
> 	 * For OMAP architecture, we only have two options
> 	 *    - sync_32k (default)
> 	 *    - gp timer
> 	 */
> 	if (!strcmp(str, "gp timer"))
> 		use_gptimer_clksrc = true;
>
> 	return 0;
> }
> early_param("clocksource", omap2_override_clocksource);

How does this interact with the existing clocksource cmdline parameter
already in kernel/time/clocksource.c? (c.f. boot_override_clocksource()) 

IMO, this duplicates that functionality but less elegantly.

What should happen is to let clocksource selection happen normally
(based on presence or lack of HW, or cmdline override.)  Once that has
happened, you can then setup_sched_clock() with parameters from querying
the clocksource itself.

Kevin

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Kevin Hilman]

"Hiremath, Vaibhav" <hvaibhav@ti.com> writes:

[...]

> I liked Santosh's idea in using command line argument "clocksource=" and 
> make decision based on this. I have implemented it and tried it on both
> OMAP3EVM and beaglebone and it works great.
>
> I have introduced something like this in mach-omap2/timer.c,
>
> static int __init omap2_override_clocksource(char* str)
> {
> 	if (!str)
> 		return 0;
> 	/*
> 	 * For OMAP architecture, we only have two options
> 	 *    - sync_32k (default)
> 	 *    - gp timer
> 	 */
> 	if (!strcmp(str, "gp timer"))
> 		use_gptimer_clksrc = true;
>
> 	return 0;
> }
> early_param("clocksource", omap2_override_clocksource);

How does this interact with the existing clocksource cmdline parameter
already in kernel/time/clocksource.c? (c.f. boot_override_clocksource()) 

IMO, this duplicates that functionality but less elegantly.

What should happen is to let clocksource selection happen normally
(based on presence or lack of HW, or cmdline override.)  Once that has
happened, you can then setup_sched_clock() with parameters from querying
the clocksource itself.

Kevin

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Apr 06, 2012 at 23:34:52, Tony Lindgren wrote:
> * Hiremath, Vaibhav <hvaibhav@ti.com> [120405 22:25]:
> > On Fri, Apr 06, 2012 at 03:03:01, Hilman, Kevin wrote:
> > > 
> > > What we need is only one-time selection at boot based on presence (or
> > > not) of various timers.  IOW, we still only ever need to call
> > > setup_sched_clock() once based on which HW timers are available.
> > > 
> > > Why not just delay the setup_sched_clock() until the clocksource is
> > > decided?
> 
> I think that's we're already doing for omap1 as 15xx does not
> have the 32 KiHz timer and the CONFIG_OMAP_32K_TIMER is no longer
> conflicting with the MPU timer.
> 

No we are not delaying anything here, we still are calling 
setup_sched_clock() function in timer->init() callback.
The call sequence for omap1 is,

struct sys_timer omap1_timer = {
	.init           = omap1_timer_init,
};

static void __init omap1_timer_init(void)
{
	if (!omap_32k_timer_usable())
		omap_mpu_timer_init();
}

omap_32k_timer_usable() is just return for omap730 & omap15xx and fallback to omap_mpu_timer_init(). For all other platforms, 32ksync timer init call 
happens.
In both the cases, setup_sched_clock() is called.


> > I liked Santosh's idea in using command line argument "clocksource=" and 
> > make decision based on this. I have implemented it and tried it on both
> > OMAP3EVM and beaglebone and it works great.
> > 
> > I have introduced something like this in mach-omap2/timer.c,
> > 
> > static int __init omap2_override_clocksource(char* str)
> > {
> > 	if (!str)
> > 		return 0;
> > 	/*
> > 	 * For OMAP architecture, we only have two options
> > 	 *    - sync_32k (default)
> > 	 *    - gp timer
> > 	 */
> > 	if (!strcmp(str, "gp timer"))
> > 		use_gptimer_clksrc = true;
> > 
> > 	return 0;
> > }
> > early_param("clocksource", omap2_override_clocksource);
> 
> Sure a cmdline override is nice to have for user selection.
> But we should also by default do the right thing based on what the
> board wants in .timer entry. 
>  

I did not understand what exactly you are trying to point here.
I think we are doing exactly what board needs in .timer. 

> > It solves all issues what we have been trying address.
> 
> I'm a bit confused.. Can you briefly summarize again what all
> issues you're having? Just want to select a different clocksource
> for beaglebone? If you don't have the 32 KiHz then that can't
> be selected naturally?
> 

Let me summarize it here again,

Currently, the timer code is using config option CONFIG_OMAP_32K_TIMER,
to choose between 32ksync counter and gptimer; it is compile time option.
If user wants to use gptimer for HR ticks, he must build the kernel without
CONFIG_OMAP_32K_TIMER option.

AM335x family of devices doesn't have 32ksync_counter available, only option 
here is to use gptimer for kernel clocksource and clockevents.

So in order to support, multi-omap build including devices like AM335x, we 
must get rid of this option CONFIG_OMAP_32K_TIMER, atleast from clocksource 
registration perspective.

So that means, we need to have some mechanism to handle or detect available 
clocksource runtime. Options would be,

 - Use HWMOD to detect availability of 32ksync_counter, else fallback 
   to gptimer. [This was my original patch]

   But this restricts the use of gptimer completely on omap architecture, 
   where we have 32ksync counter module.

 - So the next solution is to still keep compile time option, so that user 
   will get to use gptimer atleast just changing the kernel config option.

   But, still, this is going to be kernel rebuild.

 - Next option came up was, register both the timers and override using 
   kernel parameter. 

   This will work only if, both the timers run at same rate/frequency; since
   we have one more layer here setup_sched_clock(), which actually can be 
   called only once.

 - Next option suggested by Santosh, is to use kernel parameter as in parse
   it early, to make decision on if user wants to override default 
   clocksource (32ksync)
   
   This is something will work for us and solves all above issues.

I have validated it on OMAP3EVM and it seems to be working for me without 
any issues.

Thanks,
Vaibhav

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Fri, Apr 06, 2012 at 23:34:52, Tony Lindgren wrote:
> * Hiremath, Vaibhav <hvaibhav@ti.com> [120405 22:25]:
> > On Fri, Apr 06, 2012 at 03:03:01, Hilman, Kevin wrote:
> > > 
> > > What we need is only one-time selection at boot based on presence (or
> > > not) of various timers.  IOW, we still only ever need to call
> > > setup_sched_clock() once based on which HW timers are available.
> > > 
> > > Why not just delay the setup_sched_clock() until the clocksource is
> > > decided?
> 
> I think that's we're already doing for omap1 as 15xx does not
> have the 32 KiHz timer and the CONFIG_OMAP_32K_TIMER is no longer
> conflicting with the MPU timer.
> 

No we are not delaying anything here, we still are calling 
setup_sched_clock() function in timer->init() callback.
The call sequence for omap1 is,

struct sys_timer omap1_timer = {
	.init           = omap1_timer_init,
};

static void __init omap1_timer_init(void)
{
	if (!omap_32k_timer_usable())
		omap_mpu_timer_init();
}

omap_32k_timer_usable() is just return for omap730 & omap15xx and fallback to omap_mpu_timer_init(). For all other platforms, 32ksync timer init call 
happens.
In both the cases, setup_sched_clock() is called.


> > I liked Santosh's idea in using command line argument "clocksource=" and 
> > make decision based on this. I have implemented it and tried it on both
> > OMAP3EVM and beaglebone and it works great.
> > 
> > I have introduced something like this in mach-omap2/timer.c,
> > 
> > static int __init omap2_override_clocksource(char* str)
> > {
> > 	if (!str)
> > 		return 0;
> > 	/*
> > 	 * For OMAP architecture, we only have two options
> > 	 *    - sync_32k (default)
> > 	 *    - gp timer
> > 	 */
> > 	if (!strcmp(str, "gp timer"))
> > 		use_gptimer_clksrc = true;
> > 
> > 	return 0;
> > }
> > early_param("clocksource", omap2_override_clocksource);
> 
> Sure a cmdline override is nice to have for user selection.
> But we should also by default do the right thing based on what the
> board wants in .timer entry. 
>  

I did not understand what exactly you are trying to point here.
I think we are doing exactly what board needs in .timer. 

> > It solves all issues what we have been trying address.
> 
> I'm a bit confused.. Can you briefly summarize again what all
> issues you're having? Just want to select a different clocksource
> for beaglebone? If you don't have the 32 KiHz then that can't
> be selected naturally?
> 

Let me summarize it here again,

Currently, the timer code is using config option CONFIG_OMAP_32K_TIMER,
to choose between 32ksync counter and gptimer; it is compile time option.
If user wants to use gptimer for HR ticks, he must build the kernel without
CONFIG_OMAP_32K_TIMER option.

AM335x family of devices doesn't have 32ksync_counter available, only option 
here is to use gptimer for kernel clocksource and clockevents.

So in order to support, multi-omap build including devices like AM335x, we 
must get rid of this option CONFIG_OMAP_32K_TIMER, atleast from clocksource 
registration perspective.

So that means, we need to have some mechanism to handle or detect available 
clocksource runtime. Options would be,

 - Use HWMOD to detect availability of 32ksync_counter, else fallback 
   to gptimer. [This was my original patch]

   But this restricts the use of gptimer completely on omap architecture, 
   where we have 32ksync counter module.

 - So the next solution is to still keep compile time option, so that user 
   will get to use gptimer atleast just changing the kernel config option.

   But, still, this is going to be kernel rebuild.

 - Next option came up was, register both the timers and override using 
   kernel parameter. 

   This will work only if, both the timers run at same rate/frequency; since
   we have one more layer here setup_sched_clock(), which actually can be 
   called only once.

 - Next option suggested by Santosh, is to use kernel parameter as in parse
   it early, to make decision on if user wants to override default 
   clocksource (32ksync)
   
   This is something will work for us and solves all above issues.

I have validated it on OMAP3EVM and it seems to be working for me without 
any issues.

Thanks,
Vaibhav

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Sat, Apr 07, 2012 at 02:48:47, Hilman, Kevin wrote:
> "Hiremath, Vaibhav" <hvaibhav@ti.com> writes:
> 
> [...]
> 
> > I liked Santosh's idea in using command line argument "clocksource=" and 
> > make decision based on this. I have implemented it and tried it on both
> > OMAP3EVM and beaglebone and it works great.
> >
> > I have introduced something like this in mach-omap2/timer.c,
> >
> > static int __init omap2_override_clocksource(char* str)
> > {
> > 	if (!str)
> > 		return 0;
> > 	/*
> > 	 * For OMAP architecture, we only have two options
> > 	 *    - sync_32k (default)
> > 	 *    - gp timer
> > 	 */
> > 	if (!strcmp(str, "gp timer"))
> > 		use_gptimer_clksrc = true;
> >
> > 	return 0;
> > }
> > early_param("clocksource", omap2_override_clocksource);
> 
> How does this interact with the existing clocksource cmdline parameter
> already in kernel/time/clocksource.c? (c.f. boot_override_clocksource()) 
> 

Not really, it doesn't interact with existing clocksource parameter
Already present in kernel/time/clocksource.c.

Both works independently...

> IMO, this duplicates that functionality but less elegantly.
> 
> What should happen is to let clocksource selection happen normally
> (based on presence or lack of HW, or cmdline override.)  Once that has
> happened, you can then setup_sched_clock() with parameters from querying
> the clocksource itself.
> 

After Russell's response, it is clear that we should not change the 
clocksource dynamically, its not useful. So I do not see any benefits
following that feature (as of now).

We just need to make sure that, we detect our clocksource and call
setup_sched_clock() with appropriate rating.

Thanks,
Vaibhav

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Sat, Apr 07, 2012 at 02:48:47, Hilman, Kevin wrote:
> "Hiremath, Vaibhav" <hvaibhav@ti.com> writes:
> 
> [...]
> 
> > I liked Santosh's idea in using command line argument "clocksource=" and 
> > make decision based on this. I have implemented it and tried it on both
> > OMAP3EVM and beaglebone and it works great.
> >
> > I have introduced something like this in mach-omap2/timer.c,
> >
> > static int __init omap2_override_clocksource(char* str)
> > {
> > 	if (!str)
> > 		return 0;
> > 	/*
> > 	 * For OMAP architecture, we only have two options
> > 	 *    - sync_32k (default)
> > 	 *    - gp timer
> > 	 */
> > 	if (!strcmp(str, "gp timer"))
> > 		use_gptimer_clksrc = true;
> >
> > 	return 0;
> > }
> > early_param("clocksource", omap2_override_clocksource);
> 
> How does this interact with the existing clocksource cmdline parameter
> already in kernel/time/clocksource.c? (c.f. boot_override_clocksource()) 
> 

Not really, it doesn't interact with existing clocksource parameter
Already present in kernel/time/clocksource.c.

Both works independently...

> IMO, this duplicates that functionality but less elegantly.
> 
> What should happen is to let clocksource selection happen normally
> (based on presence or lack of HW, or cmdline override.)  Once that has
> happened, you can then setup_sched_clock() with parameters from querying
> the clocksource itself.
> 

After Russell's response, it is clear that we should not change the 
clocksource dynamically, its not useful. So I do not see any benefits
following that feature (as of now).

We just need to make sure that, we detect our clocksource and call
setup_sched_clock() with appropriate rating.

Thanks,
Vaibhav

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Jon Hunter]

Hi Vaibhav,

On 04/09/2012 01:19 AM, Hiremath, Vaibhav wrote:

[...]

> Let me summarize it here again,
>
> Currently, the timer code is using config option CONFIG_OMAP_32K_TIMER,
> to choose between 32ksync counter and gptimer; it is compile time option.
> If user wants to use gptimer for HR ticks, he must build the kernel without
> CONFIG_OMAP_32K_TIMER option.
>
> AM335x family of devices doesn't have 32ksync_counter available, only option
> here is to use gptimer for kernel clocksource and clockevents.
>
> So in order to support, multi-omap build including devices like AM335x, we
> must get rid of this option CONFIG_OMAP_32K_TIMER, atleast from clocksource
> registration perspective.
>
> So that means, we need to have some mechanism to handle or detect available
> clocksource runtime. Options would be,
>
>   - Use HWMOD to detect availability of 32ksync_counter, else fallback
>     to gptimer. [This was my original patch]
>
>     But this restricts the use of gptimer completely on omap architecture,
>     where we have 32ksync counter module.

True, but we would always want to use the 32k timer if CONFIG_PM is 
specified. So what I am saying is that if a device has a 32ksync timer 
and CONFIG_PM is defined, we always want to use the 32ksync timer and a 
gptimer should never be used.

So we should/must restrict the use of a gptimer is CONFIG_PM is enabled 
for devices that have the 32ksync timer.

>   - So the next solution is to still keep compile time option, so that user
>     will get to use gptimer atleast just changing the kernel config option.
>
>     But, still, this is going to be kernel rebuild.
>
>   - Next option came up was, register both the timers and override using
>     kernel parameter.
>
>     This will work only if, both the timers run at same rate/frequency; since
>     we have one more layer here setup_sched_clock(), which actually can be
>     called only once.
>
>   - Next option suggested by Santosh, is to use kernel parameter as in parse
>     it early, to make decision on if user wants to override default
>     clocksource (32ksync)
>
>     This is something will work for us and solves all above issues.

What happens if PM is enabled? Can you still override the default? I 
don't think this should be allowed for devices with a 32ksync timer.

Jon

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Jon Hunter]

Hi Vaibhav,

On 04/09/2012 01:19 AM, Hiremath, Vaibhav wrote:

[...]

> Let me summarize it here again,
>
> Currently, the timer code is using config option CONFIG_OMAP_32K_TIMER,
> to choose between 32ksync counter and gptimer; it is compile time option.
> If user wants to use gptimer for HR ticks, he must build the kernel without
> CONFIG_OMAP_32K_TIMER option.
>
> AM335x family of devices doesn't have 32ksync_counter available, only option
> here is to use gptimer for kernel clocksource and clockevents.
>
> So in order to support, multi-omap build including devices like AM335x, we
> must get rid of this option CONFIG_OMAP_32K_TIMER, atleast from clocksource
> registration perspective.
>
> So that means, we need to have some mechanism to handle or detect available
> clocksource runtime. Options would be,
>
>   - Use HWMOD to detect availability of 32ksync_counter, else fallback
>     to gptimer. [This was my original patch]
>
>     But this restricts the use of gptimer completely on omap architecture,
>     where we have 32ksync counter module.

True, but we would always want to use the 32k timer if CONFIG_PM is 
specified. So what I am saying is that if a device has a 32ksync timer 
and CONFIG_PM is defined, we always want to use the 32ksync timer and a 
gptimer should never be used.

So we should/must restrict the use of a gptimer is CONFIG_PM is enabled 
for devices that have the 32ksync timer.

>   - So the next solution is to still keep compile time option, so that user
>     will get to use gptimer atleast just changing the kernel config option.
>
>     But, still, this is going to be kernel rebuild.
>
>   - Next option came up was, register both the timers and override using
>     kernel parameter.
>
>     This will work only if, both the timers run at same rate/frequency; since
>     we have one more layer here setup_sched_clock(), which actually can be
>     called only once.
>
>   - Next option suggested by Santosh, is to use kernel parameter as in parse
>     it early, to make decision on if user wants to override default
>     clocksource (32ksync)
>
>     This is something will work for us and solves all above issues.

What happens if PM is enabled? Can you still override the default? I 
don't think this should be allowed for devices with a 32ksync timer.

Jon

RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Apr 10, 2012 at 01:48:22, Hunter, Jon wrote:
> Hi Vaibhav,
> 
> On 04/09/2012 01:19 AM, Hiremath, Vaibhav wrote:
> 
> [...]
> 
> > Let me summarize it here again,
> >
> > Currently, the timer code is using config option CONFIG_OMAP_32K_TIMER,
> > to choose between 32ksync counter and gptimer; it is compile time option.
> > If user wants to use gptimer for HR ticks, he must build the kernel without
> > CONFIG_OMAP_32K_TIMER option.
> >
> > AM335x family of devices doesn't have 32ksync_counter available, only option
> > here is to use gptimer for kernel clocksource and clockevents.
> >
> > So in order to support, multi-omap build including devices like AM335x, we
> > must get rid of this option CONFIG_OMAP_32K_TIMER, atleast from clocksource
> > registration perspective.
> >
> > So that means, we need to have some mechanism to handle or detect available
> > clocksource runtime. Options would be,
> >
> >   - Use HWMOD to detect availability of 32ksync_counter, else fallback
> >     to gptimer. [This was my original patch]
> >
> >     But this restricts the use of gptimer completely on omap architecture,
> >     where we have 32ksync counter module.
> 
> True, but we would always want to use the 32k timer if CONFIG_PM is 
> specified. So what I am saying is that if a device has a 32ksync timer 
> and CONFIG_PM is defined, we always want to use the 32ksync timer and a 
> gptimer should never be used.
> 
> So we should/must restrict the use of a gptimer is CONFIG_PM is enabled 
> for devices that have the 32ksync timer.
> 
> >   - So the next solution is to still keep compile time option, so that user
> >     will get to use gptimer atleast just changing the kernel config option.
> >
> >     But, still, this is going to be kernel rebuild.
> >
> >   - Next option came up was, register both the timers and override using
> >     kernel parameter.
> >
> >     This will work only if, both the timers run at same rate/frequency; since
> >     we have one more layer here setup_sched_clock(), which actually can be
> >     called only once.
> >
> >   - Next option suggested by Santosh, is to use kernel parameter as in parse
> >     it early, to make decision on if user wants to override default
> >     clocksource (32ksync)
> >
> >     This is something will work for us and solves all above issues.
> 
> What happens if PM is enabled? Can you still override the default? I 
> don't think this should be allowed for devices with a 32ksync timer.
> 

If user is overriding it explicitly, that itself means he knows what he
is doing here. I too much to ask for...and unnecessary thing or expectation
from SW.

Thanks,
Vaibhav

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Hiremath, Vaibhav]

On Tue, Apr 10, 2012 at 01:48:22, Hunter, Jon wrote:
> Hi Vaibhav,
> 
> On 04/09/2012 01:19 AM, Hiremath, Vaibhav wrote:
> 
> [...]
> 
> > Let me summarize it here again,
> >
> > Currently, the timer code is using config option CONFIG_OMAP_32K_TIMER,
> > to choose between 32ksync counter and gptimer; it is compile time option.
> > If user wants to use gptimer for HR ticks, he must build the kernel without
> > CONFIG_OMAP_32K_TIMER option.
> >
> > AM335x family of devices doesn't have 32ksync_counter available, only option
> > here is to use gptimer for kernel clocksource and clockevents.
> >
> > So in order to support, multi-omap build including devices like AM335x, we
> > must get rid of this option CONFIG_OMAP_32K_TIMER, atleast from clocksource
> > registration perspective.
> >
> > So that means, we need to have some mechanism to handle or detect available
> > clocksource runtime. Options would be,
> >
> >   - Use HWMOD to detect availability of 32ksync_counter, else fallback
> >     to gptimer. [This was my original patch]
> >
> >     But this restricts the use of gptimer completely on omap architecture,
> >     where we have 32ksync counter module.
> 
> True, but we would always want to use the 32k timer if CONFIG_PM is 
> specified. So what I am saying is that if a device has a 32ksync timer 
> and CONFIG_PM is defined, we always want to use the 32ksync timer and a 
> gptimer should never be used.
> 
> So we should/must restrict the use of a gptimer is CONFIG_PM is enabled 
> for devices that have the 32ksync timer.
> 
> >   - So the next solution is to still keep compile time option, so that user
> >     will get to use gptimer atleast just changing the kernel config option.
> >
> >     But, still, this is going to be kernel rebuild.
> >
> >   - Next option came up was, register both the timers and override using
> >     kernel parameter.
> >
> >     This will work only if, both the timers run at same rate/frequency; since
> >     we have one more layer here setup_sched_clock(), which actually can be
> >     called only once.
> >
> >   - Next option suggested by Santosh, is to use kernel parameter as in parse
> >     it early, to make decision on if user wants to override default
> >     clocksource (32ksync)
> >
> >     This is something will work for us and solves all above issues.
> 
> What happens if PM is enabled? Can you still override the default? I 
> don't think this should be allowed for devices with a 32ksync timer.
> 

If user is overriding it explicitly, that itself means he knows what he
is doing here. I too much to ask for...and unnecessary thing or expectation
from SW.

Thanks,
Vaibhav

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Russell King - ARM Linux]

On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
> True, but we would always want to use the 32k timer if CONFIG_PM is  
> specified. So what I am saying is that if a device has a 32ksync timer  
> and CONFIG_PM is defined, we always want to use the 32ksync timer and a  
> gptimer should never be used.

Why?  What if you want to have PM enabled, and you also want to use the
kernels high resolution timers, or you want more accurate timing than
the 30.5us tick interval of the 32k timer?

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Russell King - ARM Linux]

On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
> True, but we would always want to use the 32k timer if CONFIG_PM is  
> specified. So what I am saying is that if a device has a 32ksync timer  
> and CONFIG_PM is defined, we always want to use the 32ksync timer and a  
> gptimer should never be used.

Why?  What if you want to have PM enabled, and you also want to use the
kernels high resolution timers, or you want more accurate timing than
the 30.5us tick interval of the 32k timer?

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
> On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>> True, but we would always want to use the 32k timer if CONFIG_PM is  
>> specified. So what I am saying is that if a device has a 32ksync timer  
>> and CONFIG_PM is defined, we always want to use the 32ksync timer and a  
>> gptimer should never be used.
> 
> Why?  What if you want to have PM enabled, and you also want to use the
> kernels high resolution timers, or you want more accurate timing than
> the 30.5us tick interval of the 32k timer?

You might have missed the earlier comments on the thread. High
resolution GP timer(sysclk) will stop in deeper power states and
hence it can't be used with PM enabled usecases.

Regards
Santosh

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Santosh Shilimkar]

On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
> On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>> True, but we would always want to use the 32k timer if CONFIG_PM is  
>> specified. So what I am saying is that if a device has a 32ksync timer  
>> and CONFIG_PM is defined, we always want to use the 32ksync timer and a  
>> gptimer should never be used.
> 
> Why?  What if you want to have PM enabled, and you also want to use the
> kernels high resolution timers, or you want more accurate timing than
> the 30.5us tick interval of the 32k timer?

You might have missed the earlier comments on the thread. High
resolution GP timer(sysclk) will stop in deeper power states and
hence it can't be used with PM enabled usecases.

Regards
Santosh

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Russell King - ARM Linux]

On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
> > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
> >> True, but we would always want to use the 32k timer if CONFIG_PM is  
> >> specified. So what I am saying is that if a device has a 32ksync timer  
> >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a  
> >> gptimer should never be used.
> > 
> > Why?  What if you want to have PM enabled, and you also want to use the
> > kernels high resolution timers, or you want more accurate timing than
> > the 30.5us tick interval of the 32k timer?
> 
> You might have missed the earlier comments on the thread. High
> resolution GP timer(sysclk) will stop in deeper power states and
> hence it can't be used with PM enabled usecases.

Which means folk should be given the choice at boot time between running
with the deeper power states and having a higher resolution timing source,
rather than denying them the higher resolution timing source when PM is
enabled.

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Russell King - ARM Linux]

On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
> > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
> >> True, but we would always want to use the 32k timer if CONFIG_PM is  
> >> specified. So what I am saying is that if a device has a 32ksync timer  
> >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a  
> >> gptimer should never be used.
> > 
> > Why?  What if you want to have PM enabled, and you also want to use the
> > kernels high resolution timers, or you want more accurate timing than
> > the 30.5us tick interval of the 32k timer?
> 
> You might have missed the earlier comments on the thread. High
> resolution GP timer(sysclk) will stop in deeper power states and
> hence it can't be used with PM enabled usecases.

Which means folk should be given the choice at boot time between running
with the deeper power states and having a higher resolution timing source,
rather than denying them the higher resolution timing source when PM is
enabled.

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Tue, Apr 10, 2012 at 2:59 PM, Russell King - ARM Linux
<linux@arm.linux.org.uk> wrote:
> On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
>> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
>> > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>> >> True, but we would always want to use the 32k timer if CONFIG_PM is
>> >> specified. So what I am saying is that if a device has a 32ksync timer
>> >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a
>> >> gptimer should never be used.
>> >
>> > Why?  What if you want to have PM enabled, and you also want to use the
>> > kernels high resolution timers, or you want more accurate timing than
>> > the 30.5us tick interval of the 32k timer?
>>
>> You might have missed the earlier comments on the thread. High
>> resolution GP timer(sysclk) will stop in deeper power states and
>> hence it can't be used with PM enabled usecases.
>
> Which means folk should be given the choice at boot time between running
> with the deeper power states and having a higher resolution timing source,
> rather than denying them the higher resolution timing source when PM is
> enabled.

Good point. My point is such facilities is already part of the kernel and
there is no need to add a new one. The last proposal was allowing user to
choose gptimer as a clocksource and then you already have facility to
disable C-state now so, all should work in general

Regards
Santosh
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Tue, Apr 10, 2012 at 2:59 PM, Russell King - ARM Linux
<linux@arm.linux.org.uk> wrote:
> On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
>> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
>> > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>> >> True, but we would always want to use the 32k timer if CONFIG_PM is
>> >> specified. So what I am saying is that if a device has a 32ksync timer
>> >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a
>> >> gptimer should never be used.
>> >
>> > Why? ?What if you want to have PM enabled, and you also want to use the
>> > kernels high resolution timers, or you want more accurate timing than
>> > the 30.5us tick interval of the 32k timer?
>>
>> You might have missed the earlier comments on the thread. High
>> resolution GP timer(sysclk) will stop in deeper power states and
>> hence it can't be used with PM enabled usecases.
>
> Which means folk should be given the choice at boot time between running
> with the deeper power states and having a higher resolution timing source,
> rather than denying them the higher resolution timing source when PM is
> enabled.

Good point. My point is such facilities is already part of the kernel and
there is no need to add a new one. The last proposal was allowing user to
choose gptimer as a clocksource and then you already have facility to
disable C-state now so, all should work in general

Regards
Santosh

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Jon Hunter]

On 04/10/2012 04:51 AM, Shilimkar, Santosh wrote:
> On Tue, Apr 10, 2012 at 2:59 PM, Russell King - ARM Linux
> <linux@arm.linux.org.uk>  wrote:
>> On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
>>> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
>>>> On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>>>>> True, but we would always want to use the 32k timer if CONFIG_PM is
>>>>> specified. So what I am saying is that if a device has a 32ksync timer
>>>>> and CONFIG_PM is defined, we always want to use the 32ksync timer and a
>>>>> gptimer should never be used.
>>>>
>>>> Why?  What if you want to have PM enabled, and you also want to use the
>>>> kernels high resolution timers, or you want more accurate timing than
>>>> the 30.5us tick interval of the 32k timer?
>>>
>>> You might have missed the earlier comments on the thread. High
>>> resolution GP timer(sysclk) will stop in deeper power states and
>>> hence it can't be used with PM enabled usecases.
>>
>> Which means folk should be given the choice at boot time between running
>> with the deeper power states and having a higher resolution timing source,
>> rather than denying them the higher resolution timing source when PM is
>> enabled.
>
> Good point. My point is such facilities is already part of the kernel and
> there is no need to add a new one. The last proposal was allowing user to
> choose gptimer as a clocksource and then you already have facility to
> disable C-state now so, all should work in general

Actually, thinking about this some more, you do not even need to disable 
c-states. By using a gptimer1 and configuring it to use the SYSCLK as it 
source, as long as the gptimer1 is not disabled, it will prevent SYSCLK 
from ever turning off.

Probably for good measure in this case we should also disable auto clock 
gating of SYSCLK via the PRM_CLKSRC_CTRL (OMAP2/3) or PRM_CLKREQCTRL 
(OMAP4).

Sounds like a good approach.

Jon

[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Jon Hunter]

On 04/10/2012 04:51 AM, Shilimkar, Santosh wrote:
> On Tue, Apr 10, 2012 at 2:59 PM, Russell King - ARM Linux
> <linux@arm.linux.org.uk>  wrote:
>> On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
>>> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
>>>> On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>>>>> True, but we would always want to use the 32k timer if CONFIG_PM is
>>>>> specified. So what I am saying is that if a device has a 32ksync timer
>>>>> and CONFIG_PM is defined, we always want to use the 32ksync timer and a
>>>>> gptimer should never be used.
>>>>
>>>> Why?  What if you want to have PM enabled, and you also want to use the
>>>> kernels high resolution timers, or you want more accurate timing than
>>>> the 30.5us tick interval of the 32k timer?
>>>
>>> You might have missed the earlier comments on the thread. High
>>> resolution GP timer(sysclk) will stop in deeper power states and
>>> hence it can't be used with PM enabled usecases.
>>
>> Which means folk should be given the choice at boot time between running
>> with the deeper power states and having a higher resolution timing source,
>> rather than denying them the higher resolution timing source when PM is
>> enabled.
>
> Good point. My point is such facilities is already part of the kernel and
> there is no need to add a new one. The last proposal was allowing user to
> choose gptimer as a clocksource and then you already have facility to
> disable C-state now so, all should work in general

Actually, thinking about this some more, you do not even need to disable 
c-states. By using a gptimer1 and configuring it to use the SYSCLK as it 
source, as long as the gptimer1 is not disabled, it will prevent SYSCLK 
from ever turning off.

Probably for good measure in this case we should also disable auto clock 
gating of SYSCLK via the PRM_CLKSRC_CTRL (OMAP2/3) or PRM_CLKREQCTRL 
(OMAP4).

Sounds like a good approach.

Jon

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Tue, Apr 10, 2012 at 5:51 PM, Shilimkar, Santosh
<santosh.shilimkar@ti.com> wrote:
> On Tue, Apr 10, 2012 at 2:59 PM, Russell King - ARM Linux
> <linux@arm.linux.org.uk> wrote:
>> On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
>>> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
>>> > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>>> >> True, but we would always want to use the 32k timer if CONFIG_PM is
>>> >> specified. So what I am saying is that if a device has a 32ksync timer
>>> >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a
>>> >> gptimer should never be used.
>>> >
>>> > Why?  What if you want to have PM enabled, and you also want to use the
>>> > kernels high resolution timers, or you want more accurate timing than
>>> > the 30.5us tick interval of the 32k timer?
>>>
>>> You might have missed the earlier comments on the thread. High
>>> resolution GP timer(sysclk) will stop in deeper power states and
>>> hence it can't be used with PM enabled usecases.
>>
>> Which means folk should be given the choice at boot time between running
>> with the deeper power states and having a higher resolution timing source,
>> rather than denying them the higher resolution timing source when PM is
>> enabled.
>
> Good point. My point is such facilities is already part of the kernel and
> there is no need to add a new one. The last proposal was allowing user to
> choose gptimer as a clocksource and then you already have facility to
> disable C-state now so, all should work in general

'nohlt' in boot cmd should work to prevent CPU from entering deep C-state,
which looks enough to make gptimer working well if system suspend isn't
considered.

Thanks,
-- 
Ming Lei
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Ming Lei]

On Tue, Apr 10, 2012 at 5:51 PM, Shilimkar, Santosh
<santosh.shilimkar@ti.com> wrote:
> On Tue, Apr 10, 2012 at 2:59 PM, Russell King - ARM Linux
> <linux@arm.linux.org.uk> wrote:
>> On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
>>> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
>>> > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>>> >> True, but we would always want to use the 32k timer if CONFIG_PM is
>>> >> specified. So what I am saying is that if a device has a 32ksync timer
>>> >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a
>>> >> gptimer should never be used.
>>> >
>>> > Why? ?What if you want to have PM enabled, and you also want to use the
>>> > kernels high resolution timers, or you want more accurate timing than
>>> > the 30.5us tick interval of the 32k timer?
>>>
>>> You might have missed the earlier comments on the thread. High
>>> resolution GP timer(sysclk) will stop in deeper power states and
>>> hence it can't be used with PM enabled usecases.
>>
>> Which means folk should be given the choice at boot time between running
>> with the deeper power states and having a higher resolution timing source,
>> rather than denying them the higher resolution timing source when PM is
>> enabled.
>
> Good point. My point is such facilities is already part of the kernel and
> there is no need to add a new one. The last proposal was allowing user to
> choose gptimer as a clocksource and then you already have facility to
> disable C-state now so, all should work in general

'nohlt' in boot cmd should work to prevent CPU from entering deep C-state,
which looks enough to make gptimer working well if system suspend isn't
considered.

Thanks,
-- 
Ming Lei

Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Wed, Apr 11, 2012 at 6:30 AM, Ming Lei <tom.leiming@gmail.com> wrote:
> On Tue, Apr 10, 2012 at 5:51 PM, Shilimkar, Santosh
> <santosh.shilimkar@ti.com> wrote:
>> On Tue, Apr 10, 2012 at 2:59 PM, Russell King - ARM Linux
>> <linux@arm.linux.org.uk> wrote:
>>> On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
>>>> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
>>>> > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>>>> >> True, but we would always want to use the 32k timer if CONFIG_PM is
>>>> >> specified. So what I am saying is that if a device has a 32ksync timer
>>>> >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a
>>>> >> gptimer should never be used.
>>>> >
>>>> > Why?  What if you want to have PM enabled, and you also want to use the
>>>> > kernels high resolution timers, or you want more accurate timing than
>>>> > the 30.5us tick interval of the 32k timer?
>>>>
>>>> You might have missed the earlier comments on the thread. High
>>>> resolution GP timer(sysclk) will stop in deeper power states and
>>>> hence it can't be used with PM enabled usecases.
>>>
>>> Which means folk should be given the choice at boot time between running
>>> with the deeper power states and having a higher resolution timing source,
>>> rather than denying them the higher resolution timing source when PM is
>>> enabled.
>>
>> Good point. My point is such facilities is already part of the kernel and
>> there is no need to add a new one. The last proposal was allowing user to
>> choose gptimer as a clocksource and then you already have facility to
>> disable C-state now so, all should work in general
>
> 'nohlt' in boot cmd should work to prevent CPU from entering deep C-state,
> which looks enough to make gptimer working well if system suspend isn't
> considered.
>
That's another good option

Looks like we get all the needed flexibility with the reworked patch
from Vaibhav
to choose the command like option for high res. timer source.

Regards
Santosh
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To unsubscribe from this list: send the line "unsubscribe linux-omap" in
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[PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

[Shilimkar, Santosh]

On Wed, Apr 11, 2012 at 6:30 AM, Ming Lei <tom.leiming@gmail.com> wrote:
> On Tue, Apr 10, 2012 at 5:51 PM, Shilimkar, Santosh
> <santosh.shilimkar@ti.com> wrote:
>> On Tue, Apr 10, 2012 at 2:59 PM, Russell King - ARM Linux
>> <linux@arm.linux.org.uk> wrote:
>>> On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
>>>> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
>>>> > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
>>>> >> True, but we would always want to use the 32k timer if CONFIG_PM is
>>>> >> specified. So what I am saying is that if a device has a 32ksync timer
>>>> >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a
>>>> >> gptimer should never be used.
>>>> >
>>>> > Why? ?What if you want to have PM enabled, and you also want to use the
>>>> > kernels high resolution timers, or you want more accurate timing than
>>>> > the 30.5us tick interval of the 32k timer?
>>>>
>>>> You might have missed the earlier comments on the thread. High
>>>> resolution GP timer(sysclk) will stop in deeper power states and
>>>> hence it can't be used with PM enabled usecases.
>>>
>>> Which means folk should be given the choice at boot time between running
>>> with the deeper power states and having a higher resolution timing source,
>>> rather than denying them the higher resolution timing source when PM is
>>> enabled.
>>
>> Good point. My point is such facilities is already part of the kernel and
>> there is no need to add a new one. The last proposal was allowing user to
>> choose gptimer as a clocksource and then you already have facility to
>> disable C-state now so, all should work in general
>
> 'nohlt' in boot cmd should work to prevent CPU from entering deep C-state,
> which looks enough to make gptimer working well if system suspend isn't
> considered.
>
That's another good option

Looks like we get all the needed flexibility with the reworked patch
from Vaibhav
to choose the command like option for high res. timer source.

Regards
Santosh