[Backport for linux-5.4.y PATCH 1/4] ARM: OMAP: replace setup_irq() by request_irq()

[Backport for linux-5.4.y PATCH 1/4] ARM: OMAP: replace setup_irq() by request_irq()

[Tony Lindgren]

From: afzal mohammed <afzal.mohd.ma@gmail.com>

Upstream commit b75ca5217743e4d7076cf65e044e88389e44318d backported for
stable linux-5.4.y to make it easier to apply dra7 timer errata patches.

request_irq() is preferred over setup_irq(). Invocations of setup_irq()
occur after memory allocators are ready.

Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.

Hence replace setup_irq() by request_irq().

[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Tero Kristo <kristo@kernel.org>
Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 arch/arm/mach-omap1/pm.c       | 13 ++++++-------
 arch/arm/mach-omap1/time.c     | 10 +++-------
 arch/arm/mach-omap1/timer32k.c | 10 +++-------
 arch/arm/mach-omap2/timer.c    | 11 +++--------
 4 files changed, 15 insertions(+), 29 deletions(-)

diff --git a/arch/arm/mach-omap1/pm.c b/arch/arm/mach-omap1/pm.c
--- a/arch/arm/mach-omap1/pm.c
+++ b/arch/arm/mach-omap1/pm.c
@@ -596,11 +596,6 @@ static irqreturn_t omap_wakeup_interrupt(int irq, void *dev)
 	return IRQ_HANDLED;
 }
 
-static struct irqaction omap_wakeup_irq = {
-	.name		= "peripheral wakeup",
-	.handler	= omap_wakeup_interrupt
-};
-
 
 
 static const struct platform_suspend_ops omap_pm_ops = {
@@ -613,6 +608,7 @@ static const struct platform_suspend_ops omap_pm_ops = {
 static int __init omap_pm_init(void)
 {
 	int error = 0;
+	int irq;
 
 	if (!cpu_class_is_omap1())
 		return -ENODEV;
@@ -656,9 +652,12 @@ static int __init omap_pm_init(void)
 	arm_pm_idle = omap1_pm_idle;
 
 	if (cpu_is_omap7xx())
-		setup_irq(INT_7XX_WAKE_UP_REQ, &omap_wakeup_irq);
+		irq = INT_7XX_WAKE_UP_REQ;
 	else if (cpu_is_omap16xx())
-		setup_irq(INT_1610_WAKE_UP_REQ, &omap_wakeup_irq);
+		irq = INT_1610_WAKE_UP_REQ;
+	if (request_irq(irq, omap_wakeup_interrupt, 0, "peripheral wakeup",
+			NULL))
+		pr_err("Failed to request irq %d (peripheral wakeup)\n", irq);
 
 	/* Program new power ramp-up time
 	 * (0 for most boards since we don't lower voltage when in deep sleep)
diff --git a/arch/arm/mach-omap1/time.c b/arch/arm/mach-omap1/time.c
--- a/arch/arm/mach-omap1/time.c
+++ b/arch/arm/mach-omap1/time.c
@@ -155,15 +155,11 @@ static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static struct irqaction omap_mpu_timer1_irq = {
-	.name		= "mpu_timer1",
-	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
-	.handler	= omap_mpu_timer1_interrupt,
-};
-
 static __init void omap_init_mpu_timer(unsigned long rate)
 {
-	setup_irq(INT_TIMER1, &omap_mpu_timer1_irq);
+	if (request_irq(INT_TIMER1, omap_mpu_timer1_interrupt,
+			IRQF_TIMER | IRQF_IRQPOLL, "mpu_timer1", NULL))
+		pr_err("Failed to request irq %d (mpu_timer1)\n", INT_TIMER1);
 	omap_mpu_timer_start(0, (rate / HZ) - 1, 1);
 
 	clockevent_mpu_timer1.cpumask = cpumask_of(0);
diff --git a/arch/arm/mach-omap1/timer32k.c b/arch/arm/mach-omap1/timer32k.c
--- a/arch/arm/mach-omap1/timer32k.c
+++ b/arch/arm/mach-omap1/timer32k.c
@@ -148,15 +148,11 @@ static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static struct irqaction omap_32k_timer_irq = {
-	.name		= "32KHz timer",
-	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
-	.handler	= omap_32k_timer_interrupt,
-};
-
 static __init void omap_init_32k_timer(void)
 {
-	setup_irq(INT_OS_TIMER, &omap_32k_timer_irq);
+	if (request_irq(INT_OS_TIMER, omap_32k_timer_interrupt,
+			IRQF_TIMER | IRQF_IRQPOLL, "32KHz timer", NULL))
+		pr_err("Failed to request irq %d(32KHz timer)\n", INT_OS_TIMER);
 
 	clockevent_32k_timer.cpumask = cpumask_of(0);
 	clockevents_config_and_register(&clockevent_32k_timer,
diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -91,12 +91,6 @@ static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static struct irqaction omap2_gp_timer_irq = {
-	.name		= "gp_timer",
-	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
-	.handler	= omap2_gp_timer_interrupt,
-};
-
 static int omap2_gp_timer_set_next_event(unsigned long cycles,
 					 struct clock_event_device *evt)
 {
@@ -382,8 +376,9 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 				     &clockevent_gpt.name, OMAP_TIMER_POSTED);
 	BUG_ON(res);
 
-	omap2_gp_timer_irq.dev_id = &clkev;
-	setup_irq(clkev.irq, &omap2_gp_timer_irq);
+	if (request_irq(clkev.irq, omap2_gp_timer_interrupt,
+			IRQF_TIMER | IRQF_IRQPOLL, "gp_timer", &clkev))
+		pr_err("Failed to request irq %d (gp_timer)\n", clkev.irq);
 
 	__omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);
 
-- 
2.31.1

[Backport for linux-5.4.y PATCH 2/4] ARM: OMAP2+: Prepare timer code to backport dra7 timer wrap errata i940

[Tony Lindgren]

Prepare linux-5.4.y to backport upstream timer wrap errata commit
3efe7a878a11c13b5297057bfc1e5639ce1241ce and commit
25de4ce5ed02994aea8bc111d133308f6fd62566. Earlier kernels still use
mach-omap2/timer instead of drivers/clocksource as these kernels still
depend on legacy platform code for timers. Note that earlier stable
kernels need also additional patches and will be posted separately.

We need to prepare the timer code to allow using multiple timer instances
to handle the dra7 timer wrap errata. We do this by adding struct
dmtimer_clockevent that we initialize dynamically, and update the timer
functions to use it.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Tero Kristo <kristo@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 arch/arm/mach-omap2/timer.c | 105 +++++++++++++++++++++---------------
 1 file changed, 63 insertions(+), 42 deletions(-)

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -63,15 +63,28 @@
 
 /* Clockevent code */
 
-static struct omap_dm_timer clkev;
-static struct clock_event_device clockevent_gpt;
-
 /* Clockevent hwmod for am335x and am437x suspend */
 static struct omap_hwmod *clockevent_gpt_hwmod;
 
 /* Clockesource hwmod for am437x suspend */
 static struct omap_hwmod *clocksource_gpt_hwmod;
 
+struct dmtimer_clockevent {
+	struct clock_event_device dev;
+	struct omap_dm_timer timer;
+};
+
+static struct dmtimer_clockevent clockevent;
+
+static struct omap_dm_timer *to_dmtimer(struct clock_event_device *clockevent)
+{
+	struct dmtimer_clockevent *clkevt =
+		container_of(clockevent, struct dmtimer_clockevent, dev);
+	struct omap_dm_timer *timer = &clkevt->timer;
+
+	return timer;
+}
+
 #ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
 static unsigned long arch_timer_freq;
 
@@ -83,10 +96,11 @@ void set_cntfreq(void)
 
 static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
 {
-	struct clock_event_device *evt = &clockevent_gpt;
-
-	__omap_dm_timer_write_status(&clkev, OMAP_TIMER_INT_OVERFLOW);
+	struct dmtimer_clockevent *clkevt = dev_id;
+	struct clock_event_device *evt = &clkevt->dev;
+	struct omap_dm_timer *timer = &clkevt->timer;
 
+	__omap_dm_timer_write_status(timer, OMAP_TIMER_INT_OVERFLOW);
 	evt->event_handler(evt);
 	return IRQ_HANDLED;
 }
@@ -94,7 +108,9 @@ static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
 static int omap2_gp_timer_set_next_event(unsigned long cycles,
 					 struct clock_event_device *evt)
 {
-	__omap_dm_timer_load_start(&clkev, OMAP_TIMER_CTRL_ST,
+	struct omap_dm_timer *timer = to_dmtimer(evt);
+
+	__omap_dm_timer_load_start(timer, OMAP_TIMER_CTRL_ST,
 				   0xffffffff - cycles, OMAP_TIMER_POSTED);
 
 	return 0;
@@ -102,22 +118,26 @@ static int omap2_gp_timer_set_next_event(unsigned long cycles,
 
 static int omap2_gp_timer_shutdown(struct clock_event_device *evt)
 {
-	__omap_dm_timer_stop(&clkev, OMAP_TIMER_POSTED, clkev.rate);
+	struct omap_dm_timer *timer = to_dmtimer(evt);
+
+	__omap_dm_timer_stop(timer, OMAP_TIMER_POSTED, timer->rate);
+
 	return 0;
 }
 
 static int omap2_gp_timer_set_periodic(struct clock_event_device *evt)
 {
+	struct omap_dm_timer *timer = to_dmtimer(evt);
 	u32 period;
 
-	__omap_dm_timer_stop(&clkev, OMAP_TIMER_POSTED, clkev.rate);
+	__omap_dm_timer_stop(timer, OMAP_TIMER_POSTED, timer->rate);
 
-	period = clkev.rate / HZ;
+	period = timer->rate / HZ;
 	period -= 1;
 	/* Looks like we need to first set the load value separately */
-	__omap_dm_timer_write(&clkev, OMAP_TIMER_LOAD_REG, 0xffffffff - period,
+	__omap_dm_timer_write(timer, OMAP_TIMER_LOAD_REG, 0xffffffff - period,
 			      OMAP_TIMER_POSTED);
-	__omap_dm_timer_load_start(&clkev,
+	__omap_dm_timer_load_start(timer,
 				   OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST,
 				   0xffffffff - period, OMAP_TIMER_POSTED);
 	return 0;
@@ -131,26 +151,17 @@ static void omap_clkevt_idle(struct clock_event_device *unused)
 	omap_hwmod_idle(clockevent_gpt_hwmod);
 }
 
-static void omap_clkevt_unidle(struct clock_event_device *unused)
+static void omap_clkevt_unidle(struct clock_event_device *evt)
 {
+	struct omap_dm_timer *timer = to_dmtimer(evt);
+
 	if (!clockevent_gpt_hwmod)
 		return;
 
 	omap_hwmod_enable(clockevent_gpt_hwmod);
-	__omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);
+	__omap_dm_timer_int_enable(timer, OMAP_TIMER_INT_OVERFLOW);
 }
 
-static struct clock_event_device clockevent_gpt = {
-	.features		= CLOCK_EVT_FEAT_PERIODIC |
-				  CLOCK_EVT_FEAT_ONESHOT,
-	.rating			= 300,
-	.set_next_event		= omap2_gp_timer_set_next_event,
-	.set_state_shutdown	= omap2_gp_timer_shutdown,
-	.set_state_periodic	= omap2_gp_timer_set_periodic,
-	.set_state_oneshot	= omap2_gp_timer_shutdown,
-	.tick_resume		= omap2_gp_timer_shutdown,
-};
-
 static const struct of_device_id omap_timer_match[] __initconst = {
 	{ .compatible = "ti,omap2420-timer", },
 	{ .compatible = "ti,omap3430-timer", },
@@ -360,44 +371,54 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 						const char *fck_source,
 						const char *property)
 {
+	struct dmtimer_clockevent *clkevt = &clockevent;
+	struct omap_dm_timer *timer = &clkevt->timer;
 	int res;
 
-	clkev.id = gptimer_id;
-	clkev.errata = omap_dm_timer_get_errata();
+	timer->id = gptimer_id;
+	timer->errata = omap_dm_timer_get_errata();
+	clkevt->dev.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+	clkevt->dev.rating = 300;
+	clkevt->dev.set_next_event = omap2_gp_timer_set_next_event;
+	clkevt->dev.set_state_shutdown = omap2_gp_timer_shutdown;
+	clkevt->dev.set_state_periodic = omap2_gp_timer_set_periodic;
+	clkevt->dev.set_state_oneshot = omap2_gp_timer_shutdown;
+	clkevt->dev.tick_resume = omap2_gp_timer_shutdown;
 
 	/*
 	 * For clock-event timers we never read the timer counter and
 	 * so we are not impacted by errata i103 and i767. Therefore,
 	 * we can safely ignore this errata for clock-event timers.
 	 */
-	__omap_dm_timer_override_errata(&clkev, OMAP_TIMER_ERRATA_I103_I767);
+	__omap_dm_timer_override_errata(timer, OMAP_TIMER_ERRATA_I103_I767);
 
-	res = omap_dm_timer_init_one(&clkev, fck_source, property,
-				     &clockevent_gpt.name, OMAP_TIMER_POSTED);
+	res = omap_dm_timer_init_one(timer, fck_source, property,
+				     &clkevt->dev.name, OMAP_TIMER_POSTED);
 	BUG_ON(res);
 
-	if (request_irq(clkev.irq, omap2_gp_timer_interrupt,
-			IRQF_TIMER | IRQF_IRQPOLL, "gp_timer", &clkev))
-		pr_err("Failed to request irq %d (gp_timer)\n", clkev.irq);
+	clkevt->dev.cpumask = cpu_possible_mask;
+	clkevt->dev.irq = omap_dm_timer_get_irq(timer);
+
+	if (request_irq(timer->irq, omap2_gp_timer_interrupt,
+			IRQF_TIMER | IRQF_IRQPOLL, "gp_timer", clkevt))
+		pr_err("Failed to request irq %d (gp_timer)\n", timer->irq);
 
-	__omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);
+	__omap_dm_timer_int_enable(timer, OMAP_TIMER_INT_OVERFLOW);
 
-	clockevent_gpt.cpumask = cpu_possible_mask;
-	clockevent_gpt.irq = omap_dm_timer_get_irq(&clkev);
-	clockevents_config_and_register(&clockevent_gpt, clkev.rate,
+	clockevents_config_and_register(&clkevt->dev, timer->rate,
 					3, /* Timer internal resynch latency */
 					0xffffffff);
 
 	if (soc_is_am33xx() || soc_is_am43xx()) {
-		clockevent_gpt.suspend = omap_clkevt_idle;
-		clockevent_gpt.resume = omap_clkevt_unidle;
+		clkevt->dev.suspend = omap_clkevt_idle;
+		clkevt->dev.resume = omap_clkevt_unidle;
 
 		clockevent_gpt_hwmod =
-			omap_hwmod_lookup(clockevent_gpt.name);
+			omap_hwmod_lookup(clkevt->dev.name);
 	}
 
-	pr_info("OMAP clockevent source: %s at %lu Hz\n", clockevent_gpt.name,
-		clkev.rate);
+	pr_info("OMAP clockevent source: %s at %lu Hz\n", clkevt->dev.name,
+		timer->rate);
 }
 
 /* Clocksource code */
-- 
2.31.1

[Backport for linux-5.4.y PATCH 3/4] ARM: OMAP2+: Prepare to handle dra7 timer wrap issue

[Tony Lindgren]

Upstream commit 3efe7a878a11c13b5297057bfc1e5639ce1241ce backported to
stable linux-5.4.y mach-omap2/timer instead of drivers/clocksource as
linux-5.4.y still depends on legacy platform code for timers. Note that
earlier stable kernels need also additional patches and will be posted
separately.

There is a timer wrap issue on dra7 for the ARM architected timer.
In a typical clock configuration the timer fails to wrap after 388 days.

To work around the issue, we need to use timer-ti-dm timers instead.

Let's prepare for adding support for percpu timers by adding a common
dmtimer_clkevt_init_common() and call it from __omap_sync32k_timer_init().
This patch makes no intentional functional changes.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Tero Kristo <kristo@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 arch/arm/mach-omap2/timer.c | 34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -367,18 +367,21 @@ void tick_broadcast(const struct cpumask *mask)
 }
 #endif
 
-static void __init omap2_gp_clockevent_init(int gptimer_id,
-						const char *fck_source,
-						const char *property)
+static void __init dmtimer_clkevt_init_common(struct dmtimer_clockevent *clkevt,
+					      int gptimer_id,
+					      const char *fck_source,
+					      unsigned int features,
+					      const struct cpumask *cpumask,
+					      const char *property,
+					      int rating, const char *name)
 {
-	struct dmtimer_clockevent *clkevt = &clockevent;
 	struct omap_dm_timer *timer = &clkevt->timer;
 	int res;
 
 	timer->id = gptimer_id;
 	timer->errata = omap_dm_timer_get_errata();
-	clkevt->dev.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
-	clkevt->dev.rating = 300;
+	clkevt->dev.features = features;
+	clkevt->dev.rating = rating;
 	clkevt->dev.set_next_event = omap2_gp_timer_set_next_event;
 	clkevt->dev.set_state_shutdown = omap2_gp_timer_shutdown;
 	clkevt->dev.set_state_periodic = omap2_gp_timer_set_periodic;
@@ -396,19 +399,15 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 				     &clkevt->dev.name, OMAP_TIMER_POSTED);
 	BUG_ON(res);
 
-	clkevt->dev.cpumask = cpu_possible_mask;
+	clkevt->dev.cpumask = cpumask;
 	clkevt->dev.irq = omap_dm_timer_get_irq(timer);
 
-	if (request_irq(timer->irq, omap2_gp_timer_interrupt,
-			IRQF_TIMER | IRQF_IRQPOLL, "gp_timer", clkevt))
-		pr_err("Failed to request irq %d (gp_timer)\n", timer->irq);
+	if (request_irq(clkevt->dev.irq, omap2_gp_timer_interrupt,
+			IRQF_TIMER | IRQF_IRQPOLL, name, clkevt))
+		pr_err("Failed to request irq %d (gp_timer)\n", clkevt->dev.irq);
 
 	__omap_dm_timer_int_enable(timer, OMAP_TIMER_INT_OVERFLOW);
 
-	clockevents_config_and_register(&clkevt->dev, timer->rate,
-					3, /* Timer internal resynch latency */
-					0xffffffff);
-
 	if (soc_is_am33xx() || soc_is_am43xx()) {
 		clkevt->dev.suspend = omap_clkevt_idle;
 		clkevt->dev.resume = omap_clkevt_unidle;
@@ -558,7 +557,12 @@ static void __init __omap_sync32k_timer_init(int clkev_nr, const char *clkev_src
 {
 	omap_clk_init();
 	omap_dmtimer_init();
-	omap2_gp_clockevent_init(clkev_nr, clkev_src, clkev_prop);
+	dmtimer_clkevt_init_common(&clockevent, clkev_nr, clkev_src,
+				   CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+				   cpu_possible_mask, clkev_prop, 300, "clockevent");
+	clockevents_config_and_register(&clockevent.dev, clockevent.timer.rate,
+					3, /* Timer internal resynch latency */
+					0xffffffff);
 
 	/* Enable the use of clocksource="gp_timer" kernel parameter */
 	if (use_gptimer_clksrc || gptimer)
-- 
2.31.1

[Backport for linux-5.4.y PATCH 4/4] ARM: OMAP2+: Handle dra7 timer wrap errata i940

[Tony Lindgren]

Upstream commit 25de4ce5ed02994aea8bc111d133308f6fd62566 backported to
stable linux-5.4.y mach-omap2/timer instead of drivers/clocksource as
earlier kernels still depend on legacy platform code for timers. Note
that earlier stable kernels need also additional patches and will be
posted separately.

There is a timer wrap issue on dra7 for the ARM architected timer.
In a typical clock configuration the timer fails to wrap after 388 days.

To work around the issue, we need to use timer-ti-dm percpu timers instead.

Let's configure dmtimer3 and 4 as percpu timers by default, and warn about
the issue if the dtb is not configured properly.

For more information, please see the errata for "AM572x Sitara Processors
Silicon Revisions 1.1, 2.0":

https://www.ti.com/lit/er/sprz429m/sprz429m.pdf

The concept is based on earlier reference patches done by Tero Kristo and
Keerthy.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Tero Kristo <kristo@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 arch/arm/boot/dts/dra7-l4.dtsi      |  4 +--
 arch/arm/boot/dts/dra7.dtsi         | 20 +++++++++++
 arch/arm/mach-omap2/board-generic.c |  4 +--
 arch/arm/mach-omap2/timer.c         | 53 ++++++++++++++++++++++++++++-
 drivers/clk/ti/clk-7xx.c            |  1 +
 include/linux/cpuhotplug.h          |  1 +
 6 files changed, 78 insertions(+), 5 deletions(-)

diff --git a/arch/arm/boot/dts/dra7-l4.dtsi b/arch/arm/boot/dts/dra7-l4.dtsi
--- a/arch/arm/boot/dts/dra7-l4.dtsi
+++ b/arch/arm/boot/dts/dra7-l4.dtsi
@@ -1176,7 +1176,7 @@
 			};
 		};
 
-		target-module@34000 {			/* 0x48034000, ap 7 46.0 */
+		timer3_target: target-module@34000 {	/* 0x48034000, ap 7 46.0 */
 			compatible = "ti,sysc-omap4-timer", "ti,sysc";
 			ti,hwmods = "timer3";
 			reg = <0x34000 0x4>,
@@ -1204,7 +1204,7 @@
 			};
 		};
 
-		target-module@36000 {			/* 0x48036000, ap 9 4e.0 */
+		timer4_target: target-module@36000 {	/* 0x48036000, ap 9 4e.0 */
 			compatible = "ti,sysc-omap4-timer", "ti,sysc";
 			ti,hwmods = "timer4";
 			reg = <0x36000 0x4>,
diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
--- a/arch/arm/boot/dts/dra7.dtsi
+++ b/arch/arm/boot/dts/dra7.dtsi
@@ -46,6 +46,7 @@
 
 	timer {
 		compatible = "arm,armv7-timer";
+		status = "disabled";	/* See ARM architected timer wrap erratum i940 */
 		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>,
 			     <GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>,
 			     <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>,
@@ -766,3 +767,22 @@
 
 #include "dra7-l4.dtsi"
 #include "dra7xx-clocks.dtsi"
+
+/* Local timers, see ARM architected timer wrap erratum i940 */
+&timer3_target {
+	ti,no-reset-on-init;
+	ti,no-idle;
+	timer@0 {
+		assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER3_CLKCTRL 24>;
+		assigned-clock-parents = <&timer_sys_clk_div>;
+	};
+};
+
+&timer4_target {
+	ti,no-reset-on-init;
+	ti,no-idle;
+	timer@0 {
+		assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER4_CLKCTRL 24>;
+		assigned-clock-parents = <&timer_sys_clk_div>;
+	};
+};
diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c
--- a/arch/arm/mach-omap2/board-generic.c
+++ b/arch/arm/mach-omap2/board-generic.c
@@ -327,7 +327,7 @@ DT_MACHINE_START(DRA74X_DT, "Generic DRA74X (Flattened Device Tree)")
 	.init_late	= dra7xx_init_late,
 	.init_irq	= omap_gic_of_init,
 	.init_machine	= omap_generic_init,
-	.init_time	= omap5_realtime_timer_init,
+	.init_time	= omap3_gptimer_timer_init,
 	.dt_compat	= dra74x_boards_compat,
 	.restart	= omap44xx_restart,
 MACHINE_END
@@ -350,7 +350,7 @@ DT_MACHINE_START(DRA72X_DT, "Generic DRA72X (Flattened Device Tree)")
 	.init_late	= dra7xx_init_late,
 	.init_irq	= omap_gic_of_init,
 	.init_machine	= omap_generic_init,
-	.init_time	= omap5_realtime_timer_init,
+	.init_time	= omap3_gptimer_timer_init,
 	.dt_compat	= dra72x_boards_compat,
 	.restart	= omap44xx_restart,
 MACHINE_END
diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -42,6 +42,7 @@
 #include <linux/platform_device.h>
 #include <linux/platform_data/dmtimer-omap.h>
 #include <linux/sched_clock.h>
+#include <linux/cpu.h>
 
 #include <asm/mach/time.h>
 
@@ -420,6 +421,53 @@ static void __init dmtimer_clkevt_init_common(struct dmtimer_clockevent *clkevt,
 		timer->rate);
 }
 
+static DEFINE_PER_CPU(struct dmtimer_clockevent, dmtimer_percpu_timer);
+
+static int omap_gptimer_starting_cpu(unsigned int cpu)
+{
+	struct dmtimer_clockevent *clkevt = per_cpu_ptr(&dmtimer_percpu_timer, cpu);
+	struct clock_event_device *dev = &clkevt->dev;
+	struct omap_dm_timer *timer = &clkevt->timer;
+
+	clockevents_config_and_register(dev, timer->rate, 3, ULONG_MAX);
+	irq_force_affinity(dev->irq, cpumask_of(cpu));
+
+	return 0;
+}
+
+static int __init dmtimer_percpu_quirk_init(void)
+{
+	struct dmtimer_clockevent *clkevt;
+	struct clock_event_device *dev;
+	struct device_node *arm_timer;
+	struct omap_dm_timer *timer;
+	int cpu = 0;
+
+	arm_timer = of_find_compatible_node(NULL, NULL, "arm,armv7-timer");
+	if (of_device_is_available(arm_timer)) {
+		pr_warn_once("ARM architected timer wrap issue i940 detected\n");
+		return 0;
+	}
+
+	for_each_possible_cpu(cpu) {
+		clkevt = per_cpu_ptr(&dmtimer_percpu_timer, cpu);
+		dev = &clkevt->dev;
+		timer = &clkevt->timer;
+
+		dmtimer_clkevt_init_common(clkevt, 0, "timer_sys_ck",
+					   CLOCK_EVT_FEAT_ONESHOT,
+					   cpumask_of(cpu),
+					   "assigned-clock-parents",
+					   500, "percpu timer");
+	}
+
+	cpuhp_setup_state(CPUHP_AP_OMAP_DM_TIMER_STARTING,
+			  "clockevents/omap/gptimer:starting",
+			  omap_gptimer_starting_cpu, NULL);
+
+	return 0;
+}
+
 /* Clocksource code */
 static struct omap_dm_timer clksrc;
 static bool use_gptimer_clksrc __initdata;
@@ -564,6 +612,9 @@ static void __init __omap_sync32k_timer_init(int clkev_nr, const char *clkev_src
 					3, /* Timer internal resynch latency */
 					0xffffffff);
 
+	if (soc_is_dra7xx())
+		dmtimer_percpu_quirk_init();
+
 	/* Enable the use of clocksource="gp_timer" kernel parameter */
 	if (use_gptimer_clksrc || gptimer)
 		omap2_gptimer_clocksource_init(clksrc_nr, clksrc_src,
@@ -591,7 +642,7 @@ void __init omap3_secure_sync32k_timer_init(void)
 #endif /* CONFIG_ARCH_OMAP3 */
 
 #if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) || \
-	defined(CONFIG_SOC_AM43XX)
+	defined(CONFIG_SOC_AM43XX) || defined(CONFIG_SOC_DRA7XX)
 void __init omap3_gptimer_timer_init(void)
 {
 	__omap_sync32k_timer_init(2, "timer_sys_ck", NULL,
diff --git a/drivers/clk/ti/clk-7xx.c b/drivers/clk/ti/clk-7xx.c
--- a/drivers/clk/ti/clk-7xx.c
+++ b/drivers/clk/ti/clk-7xx.c
@@ -793,6 +793,7 @@ static struct ti_dt_clk dra7xx_clks[] = {
 	DT_CLK(NULL, "timer_32k_ck", "sys_32k_ck"),
 	DT_CLK(NULL, "sys_clkin_ck", "timer_sys_clk_div"),
 	DT_CLK(NULL, "sys_clkin", "sys_clkin1"),
+	DT_CLK(NULL, "timer_sys_ck", "timer_sys_clk_div"),
 	DT_CLK(NULL, "atl_dpll_clk_mux", "atl-clkctrl:0000:24"),
 	DT_CLK(NULL, "atl_gfclk_mux", "atl-clkctrl:0000:26"),
 	DT_CLK(NULL, "dcan1_sys_clk_mux", "wkupaon-clkctrl:0068:24"),
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -119,6 +119,7 @@ enum cpuhp_state {
 	CPUHP_AP_ARM_L2X0_STARTING,
 	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
 	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
+	CPUHP_AP_OMAP_DM_TIMER_STARTING,
 	CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
 	CPUHP_AP_JCORE_TIMER_STARTING,
 	CPUHP_AP_ARM_TWD_STARTING,
-- 
2.31.1

Re: [Backport for linux-5.4.y PATCH 2/4] ARM: OMAP2+: Prepare timer code to backport dra7 timer wrap errata i940

[Greg KH]

On Wed, Jun 02, 2021 at 01:46:23PM +0300, Tony Lindgren wrote:
> Prepare linux-5.4.y to backport upstream timer wrap errata commit
> 3efe7a878a11c13b5297057bfc1e5639ce1241ce and commit
> 25de4ce5ed02994aea8bc111d133308f6fd62566. Earlier kernels still use
> mach-omap2/timer instead of drivers/clocksource as these kernels still
> depend on legacy platform code for timers. Note that earlier stable
> kernels need also additional patches and will be posted separately.

I do not understand this paragraph.

What upstream commit is this?  And "posted separately" shouldn't show up
in a changelog text, right?

Can you fix this up to make this obvious what is happening here and make
a patch series that I can take without editing changelog text?

thanks,

greg k-h

Re: [Backport for linux-5.4.y PATCH 2/4] ARM: OMAP2+: Prepare timer code to backport dra7 timer wrap errata i940

[Tony Lindgren]

Hi,

* Greg KH <greg@kroah.com> [210608 17:13]:
> On Wed, Jun 02, 2021 at 01:46:23PM +0300, Tony Lindgren wrote:
> > Prepare linux-5.4.y to backport upstream timer wrap errata commit
> > 3efe7a878a11c13b5297057bfc1e5639ce1241ce and commit
> > 25de4ce5ed02994aea8bc111d133308f6fd62566. Earlier kernels still use
> > mach-omap2/timer instead of drivers/clocksource as these kernels still
> > depend on legacy platform code for timers. Note that earlier stable
> > kernels need also additional patches and will be posted separately.
> 
> I do not understand this paragraph.
> 
> What upstream commit is this?  And "posted separately" shouldn't show up
> in a changelog text, right?

This would be a partial backport to add struct dmtimer_clockevent from
commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 to the platform timer
code used in the older kernels.

How about the following for the description:

Upstream commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 usage of
struct dmtimer_clockevent backported to the platform timer code
still used in linux-5.4.y stable kernel. Needed to backport upstream
commit 3efe7a878a11c13b5297057bfc1e5639ce1241ce and commit
25de4ce5ed02994aea8bc111d133308f6fd62566. Earlier kernels use
mach-omap2/timer instead of drivers/clocksource as these kernels still
depend on legacy platform code for booting.

> Can you fix this up to make this obvious what is happening here and make
> a patch series that I can take without editing changelog text?

Sure I'll repost the series, assuming the above is OK for description :)
Please let me know if you need further details added.

Hmm so what's the correct way to prevent automatically applying these
into the earlier stable kernels?

For earlier stable kernels, these changes depend on at least some
additional clock related changes.

Regards,

Tony

Re: [Backport for linux-5.4.y PATCH 2/4] ARM: OMAP2+: Prepare timer code to backport dra7 timer wrap errata i940

[Greg KH]

On Wed, Jun 09, 2021 at 09:13:53AM +0300, Tony Lindgren wrote:
> Hi,
> 
> * Greg KH <greg@kroah.com> [210608 17:13]:
> > On Wed, Jun 02, 2021 at 01:46:23PM +0300, Tony Lindgren wrote:
> > > Prepare linux-5.4.y to backport upstream timer wrap errata commit
> > > 3efe7a878a11c13b5297057bfc1e5639ce1241ce and commit
> > > 25de4ce5ed02994aea8bc111d133308f6fd62566. Earlier kernels still use
> > > mach-omap2/timer instead of drivers/clocksource as these kernels still
> > > depend on legacy platform code for timers. Note that earlier stable
> > > kernels need also additional patches and will be posted separately.
> > 
> > I do not understand this paragraph.
> > 
> > What upstream commit is this?  And "posted separately" shouldn't show up
> > in a changelog text, right?
> 
> This would be a partial backport to add struct dmtimer_clockevent from
> commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 to the platform timer
> code used in the older kernels.
> 
> How about the following for the description:
> 
> Upstream commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 usage of
> struct dmtimer_clockevent backported to the platform timer code
> still used in linux-5.4.y stable kernel. Needed to backport upstream
> commit 3efe7a878a11c13b5297057bfc1e5639ce1241ce and commit
> 25de4ce5ed02994aea8bc111d133308f6fd62566. Earlier kernels use
> mach-omap2/timer instead of drivers/clocksource as these kernels still
> depend on legacy platform code for booting.

Why are you combining 2 commits into one here?

I do not understand what this commit really is at all still, sorry.

How about just providing backports for the individual commits, do not
combine them as that just is a mess.

> > Can you fix this up to make this obvious what is happening here and make
> > a patch series that I can take without editing changelog text?
> 
> Sure I'll repost the series, assuming the above is OK for description :)
> Please let me know if you need further details added.
> 
> Hmm so what's the correct way to prevent automatically applying these
> into the earlier stable kernels?

What would cause them to be automatically applied?  You need to let us
know what kernel(s) they should go to.

thanks,

greg k-h

Re: [Backport for linux-5.4.y PATCH 2/4] ARM: OMAP2+: Prepare timer code to backport dra7 timer wrap errata i940

[Tony Lindgren]

* Greg KH <greg@kroah.com> [210609 06:22]:
> On Wed, Jun 09, 2021 at 09:13:53AM +0300, Tony Lindgren wrote:
> > How about the following for the description:
> > 
> > Upstream commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 usage of
> > struct dmtimer_clockevent backported to the platform timer code
> > still used in linux-5.4.y stable kernel. Needed to backport upstream
> > commit 3efe7a878a11c13b5297057bfc1e5639ce1241ce and commit
> > 25de4ce5ed02994aea8bc111d133308f6fd62566. Earlier kernels use
> > mach-omap2/timer instead of drivers/clocksource as these kernels still
> > depend on legacy platform code for booting.
> 
> Why are you combining 2 commits into one here?

OK so still too confusing, how about let's just have:

Upstream commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 usage of
struct dmtimer_clockevent backported to the platform timer code
still used in linux-5.4.y stable kernel.

> I do not understand what this commit really is at all still, sorry.

It allows upstream fixes for drivers/clocksource/timer-ti-dm-systimer.c
to be backported to the legacy platform timer code in linux-5.4.y in
arch/arm/mach-omap2/timer.c.

We assume a single dmtimer clockevent instance only in linux-5.4.y
kernels, while for the dra7 hardware errata workaround we now need
extra percpu timers configured and need struct dmtimer_clockevent.

Backporting drivers/clocksource/timer-ti-dm-systimer.c directly seems
risky to me as linux-5.4.y still depends on legacy platform code for
booting and timers, including also the timer instances not used for
clocksource and clockevent. And it would be intrusive also for the
other SoCs not affected by the timer errata.

Of course the best option for folks using the stable kernels is to
move to the current long term kernel that already has the fixes for
drivers/clocksource/timer-ti-dm-systimer.c :)

> How about just providing backports for the individual commits, do not
> combine them as that just is a mess.

OK

> > Hmm so what's the correct way to prevent automatically applying these
> > into the earlier stable kernels?
> 
> What would cause them to be automatically applied?  You need to let us
> know what kernel(s) they should go to.

OK thanks, good to hear.

Regards,

Tony

Re: [Backport for linux-5.4.y PATCH 2/4] ARM: OMAP2+: Prepare timer code to backport dra7 timer wrap errata i940

[Greg KH]

On Wed, Jun 09, 2021 at 09:58:44AM +0300, Tony Lindgren wrote:
> * Greg KH <greg@kroah.com> [210609 06:22]:
> > On Wed, Jun 09, 2021 at 09:13:53AM +0300, Tony Lindgren wrote:
> > > How about the following for the description:
> > > 
> > > Upstream commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 usage of
> > > struct dmtimer_clockevent backported to the platform timer code
> > > still used in linux-5.4.y stable kernel. Needed to backport upstream
> > > commit 3efe7a878a11c13b5297057bfc1e5639ce1241ce and commit
> > > 25de4ce5ed02994aea8bc111d133308f6fd62566. Earlier kernels use
> > > mach-omap2/timer instead of drivers/clocksource as these kernels still
> > > depend on legacy platform code for booting.
> > 
> > Why are you combining 2 commits into one here?
> 
> OK so still too confusing, how about let's just have:
> 
> Upstream commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 usage of
> struct dmtimer_clockevent backported to the platform timer code
> still used in linux-5.4.y stable kernel.

Why not just use the normal commit message with the "upstream commit..."
message as the first line, and then in the s-o-b area add
[backported to 5.4.y - tony]

That's the normal thing we do here for backporting.

thanks,

greg k-h

Re: [Backport for linux-5.4.y PATCH 2/4] ARM: OMAP2+: Prepare timer code to backport dra7 timer wrap errata i940

[Tony Lindgren]

* Greg KH <greg@kroah.com> [210609 07:31]:
> On Wed, Jun 09, 2021 at 09:58:44AM +0300, Tony Lindgren wrote:
> > * Greg KH <greg@kroah.com> [210609 06:22]:
> > > On Wed, Jun 09, 2021 at 09:13:53AM +0300, Tony Lindgren wrote:
> > > > How about the following for the description:
> > > > 
> > > > Upstream commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 usage of
> > > > struct dmtimer_clockevent backported to the platform timer code
> > > > still used in linux-5.4.y stable kernel. Needed to backport upstream
> > > > commit 3efe7a878a11c13b5297057bfc1e5639ce1241ce and commit
> > > > 25de4ce5ed02994aea8bc111d133308f6fd62566. Earlier kernels use
> > > > mach-omap2/timer instead of drivers/clocksource as these kernels still
> > > > depend on legacy platform code for booting.
> > > 
> > > Why are you combining 2 commits into one here?
> > 
> > OK so still too confusing, how about let's just have:
> > 
> > Upstream commit 52762fbd1c4778ac9b173624ca0faacd22ef4724 usage of
> > struct dmtimer_clockevent backported to the platform timer code
> > still used in linux-5.4.y stable kernel.
> 
> Why not just use the normal commit message with the "upstream commit..."
> message as the first line, and then in the s-o-b area add
> [backported to 5.4.y - tony]
> 
> That's the normal thing we do here for backporting.

OK sure works for me thanks. I will repost the series with
updated patch descriptions.

Regards,

Tony