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From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: tglx@linutronix.de
Cc: linux-kernel@vger.kernel.org,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	Carlo Caione <carlo@caione.org>,
	Kevin Hilman <khilman@baylibre.com>,
	linux-arm-kernel@lists.infradead.org (moderated list:ARM/Amlogic
	Meson SoC support),
	linux-amlogic@lists.infradead.org (open list:ARM/Amlogic Meson
	SoC support)
Subject: [PATCH 07/25] clocksource/drivers/meson6_timer: Implement the ARM delay timer
Date: Tue, 18 Dec 2018 22:28:25 +0100	[thread overview]
Message-ID: <20181218212844.30445-7-daniel.lezcano@linaro.org> (raw)
In-Reply-To: <20181218212844.30445-1-daniel.lezcano@linaro.org>

From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

Implement an ARM delay timer to be used for udelay(). This allows us to
skip the delay loop calibration at boot.

With this patch udelay() is now independent of CPU frequency changes.
This is a good thing on Meson8, Meson8b and Meson8m2 because changing
the CPU frequency requires running the CPU clock off the XTAL while
changing the PLL or it's dividers. After changing the CPU clocks we need
to wait a few usecs for the clock to become stable. So having an
udelay() implementation that doesn't depend on the CPU frequency is
beneficial.

Suggested-by: Jianxin Pan <jianxin.pan@amlogic.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/meson6_timer.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/clocksource/meson6_timer.c b/drivers/clocksource/meson6_timer.c
index 23c7638e2bb3..84bd9479c3f8 100644
--- a/drivers/clocksource/meson6_timer.c
+++ b/drivers/clocksource/meson6_timer.c
@@ -22,6 +22,10 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 
+#ifdef CONFIG_ARM
+#include <linux/delay.h>
+#endif
+
 #define MESON_ISA_TIMER_MUX					0x00
 #define MESON_ISA_TIMER_MUX_TIMERD_EN				BIT(19)
 #define MESON_ISA_TIMER_MUX_TIMERC_EN				BIT(18)
@@ -54,6 +58,18 @@
 
 static void __iomem *timer_base;
 
+#ifdef CONFIG_ARM
+static unsigned long meson6_read_current_timer(void)
+{
+	return readl_relaxed(timer_base + MESON_ISA_TIMERE);
+}
+
+static struct delay_timer meson6_delay_timer = {
+	.read_current_timer = meson6_read_current_timer,
+	.freq = 1000 * 1000,
+};
+#endif
+
 static u64 notrace meson6_timer_sched_read(void)
 {
 	return (u64)readl(timer_base + MESON_ISA_TIMERE);
@@ -192,6 +208,12 @@ static int __init meson6_timer_init(struct device_node *node)
 
 	clockevents_config_and_register(&meson6_clockevent, USEC_PER_SEC,
 					1, 0xfffe);
+
+#ifdef CONFIG_ARM
+	/* Also use MESON_ISA_TIMERE for delays */
+	register_current_timer_delay(&meson6_delay_timer);
+#endif
+
 	return 0;
 }
 TIMER_OF_DECLARE(meson6, "amlogic,meson6-timer",
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: tglx@linutronix.de
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	Kevin Hilman <khilman@baylibre.com>,
	linux-kernel@vger.kernel.org, Carlo Caione <carlo@caione.org>,
	"open list:ARM/Amlogic Meson SoC support"
	<linux-amlogic@lists.infradead.org>,
	"moderated list:ARM/Amlogic Meson SoC support"
	<linux-arm-kernel@lists.infradead.org>
Subject: [PATCH 07/25] clocksource/drivers/meson6_timer: Implement the ARM delay timer
Date: Tue, 18 Dec 2018 22:28:25 +0100	[thread overview]
Message-ID: <20181218212844.30445-7-daniel.lezcano@linaro.org> (raw)
In-Reply-To: <20181218212844.30445-1-daniel.lezcano@linaro.org>

From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

Implement an ARM delay timer to be used for udelay(). This allows us to
skip the delay loop calibration at boot.

With this patch udelay() is now independent of CPU frequency changes.
This is a good thing on Meson8, Meson8b and Meson8m2 because changing
the CPU frequency requires running the CPU clock off the XTAL while
changing the PLL or it's dividers. After changing the CPU clocks we need
to wait a few usecs for the clock to become stable. So having an
udelay() implementation that doesn't depend on the CPU frequency is
beneficial.

Suggested-by: Jianxin Pan <jianxin.pan@amlogic.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/meson6_timer.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/clocksource/meson6_timer.c b/drivers/clocksource/meson6_timer.c
index 23c7638e2bb3..84bd9479c3f8 100644
--- a/drivers/clocksource/meson6_timer.c
+++ b/drivers/clocksource/meson6_timer.c
@@ -22,6 +22,10 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 
+#ifdef CONFIG_ARM
+#include <linux/delay.h>
+#endif
+
 #define MESON_ISA_TIMER_MUX					0x00
 #define MESON_ISA_TIMER_MUX_TIMERD_EN				BIT(19)
 #define MESON_ISA_TIMER_MUX_TIMERC_EN				BIT(18)
@@ -54,6 +58,18 @@
 
 static void __iomem *timer_base;
 
+#ifdef CONFIG_ARM
+static unsigned long meson6_read_current_timer(void)
+{
+	return readl_relaxed(timer_base + MESON_ISA_TIMERE);
+}
+
+static struct delay_timer meson6_delay_timer = {
+	.read_current_timer = meson6_read_current_timer,
+	.freq = 1000 * 1000,
+};
+#endif
+
 static u64 notrace meson6_timer_sched_read(void)
 {
 	return (u64)readl(timer_base + MESON_ISA_TIMERE);
@@ -192,6 +208,12 @@ static int __init meson6_timer_init(struct device_node *node)
 
 	clockevents_config_and_register(&meson6_clockevent, USEC_PER_SEC,
 					1, 0xfffe);
+
+#ifdef CONFIG_ARM
+	/* Also use MESON_ISA_TIMERE for delays */
+	register_current_timer_delay(&meson6_delay_timer);
+#endif
+
 	return 0;
 }
 TIMER_OF_DECLARE(meson6, "amlogic,meson6-timer",
-- 
2.17.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: tglx@linutronix.de
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	Kevin Hilman <khilman@baylibre.com>,
	linux-kernel@vger.kernel.org, Carlo Caione <carlo@caione.org>,
	"open list:ARM/Amlogic Meson SoC support"
	<linux-amlogic@lists.infradead.org>,
	"moderated list:ARM/Amlogic Meson SoC support"
	<linux-arm-kernel@lists.infradead.org>
Subject: [PATCH 07/25] clocksource/drivers/meson6_timer: Implement the ARM delay timer
Date: Tue, 18 Dec 2018 22:28:25 +0100	[thread overview]
Message-ID: <20181218212844.30445-7-daniel.lezcano@linaro.org> (raw)
In-Reply-To: <20181218212844.30445-1-daniel.lezcano@linaro.org>

From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

Implement an ARM delay timer to be used for udelay(). This allows us to
skip the delay loop calibration at boot.

With this patch udelay() is now independent of CPU frequency changes.
This is a good thing on Meson8, Meson8b and Meson8m2 because changing
the CPU frequency requires running the CPU clock off the XTAL while
changing the PLL or it's dividers. After changing the CPU clocks we need
to wait a few usecs for the clock to become stable. So having an
udelay() implementation that doesn't depend on the CPU frequency is
beneficial.

Suggested-by: Jianxin Pan <jianxin.pan@amlogic.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/meson6_timer.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/clocksource/meson6_timer.c b/drivers/clocksource/meson6_timer.c
index 23c7638e2bb3..84bd9479c3f8 100644
--- a/drivers/clocksource/meson6_timer.c
+++ b/drivers/clocksource/meson6_timer.c
@@ -22,6 +22,10 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 
+#ifdef CONFIG_ARM
+#include <linux/delay.h>
+#endif
+
 #define MESON_ISA_TIMER_MUX					0x00
 #define MESON_ISA_TIMER_MUX_TIMERD_EN				BIT(19)
 #define MESON_ISA_TIMER_MUX_TIMERC_EN				BIT(18)
@@ -54,6 +58,18 @@
 
 static void __iomem *timer_base;
 
+#ifdef CONFIG_ARM
+static unsigned long meson6_read_current_timer(void)
+{
+	return readl_relaxed(timer_base + MESON_ISA_TIMERE);
+}
+
+static struct delay_timer meson6_delay_timer = {
+	.read_current_timer = meson6_read_current_timer,
+	.freq = 1000 * 1000,
+};
+#endif
+
 static u64 notrace meson6_timer_sched_read(void)
 {
 	return (u64)readl(timer_base + MESON_ISA_TIMERE);
@@ -192,6 +208,12 @@ static int __init meson6_timer_init(struct device_node *node)
 
 	clockevents_config_and_register(&meson6_clockevent, USEC_PER_SEC,
 					1, 0xfffe);
+
+#ifdef CONFIG_ARM
+	/* Also use MESON_ISA_TIMERE for delays */
+	register_current_timer_delay(&meson6_delay_timer);
+#endif
+
 	return 0;
 }
 TIMER_OF_DECLARE(meson6, "amlogic,meson6-timer",
-- 
2.17.1


_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic

  parent reply	other threads:[~2018-12-18 21:31 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-18 21:27 [GIT PULL] timers for 4.21 Daniel Lezcano
2018-12-18 21:28 ` [PATCH 01/25] clocksource/drivers/timer-vt8500: Remove duplicate function name Daniel Lezcano
2018-12-18 21:28   ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 02/25] clocksource/drivers/dbx500: Demote dbx500 PRCMU clocksource Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 03/25] clocksource/drivers/ux500: Drop Ux500 custom SCHED_CLOCK Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 04/25] clocksource/drivers/timer-ti-dm: Remove the early platform driver registration Daniel Lezcano
2018-12-18 21:28   ` [PATCH 05/25] clockevents/drivers/tegra20: Remove obsolete inclusion of <asm/smp_twd.h> Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 06/25] clocksource/drivers/meson6_timer: Use register names from the datasheet Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` Daniel Lezcano [this message]
2018-12-18 21:28     ` [PATCH 07/25] clocksource/drivers/meson6_timer: Implement the ARM delay timer Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 08/25] clocksource/drivers/imx-gpt: Add support for ARM64 Daniel Lezcano
2018-12-18 21:28   ` [PATCH 09/25] clocksource/drivers/imx-gpt: Remove unnecessary irq protection Daniel Lezcano
2018-12-18 21:28   ` [PATCH 10/25] dt-bindings: timer: renesas, cmt: Document r8a7796 CMT support Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 11/25] dt-bindings: timer: renesas, cmt: Document r8a77470 " Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 12/25] clocksource/drivers/arc_timer: Utilize generic sched_clock Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
     [not found]     ` <20181219012457.EC02721871@mail.kernel.org>
2018-12-19  9:06       ` Alexey Brodkin
2018-12-19  9:06         ` Alexey Brodkin
2018-12-18 21:28   ` [PATCH 13/25] clocksource/drivers/timer-imx-tpm: Convert the driver to timer-of Daniel Lezcano
2018-12-18 21:28   ` [PATCH 14/25] dt-bindings: timer: renesas, cmt: Document r8a774a1 CMT support Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 15/25] clocksource/drivers/bcm2835: Switch to SPDX identifier Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 16/25] clocksource/drivers/integrator-ap: Add missing of_node_put() Daniel Lezcano
2018-12-18 21:28   ` [PATCH 17/25] clocksource/drivers/fttmr010: Fix invalid interrupt register access Daniel Lezcano
2018-12-18 21:28   ` [PATCH 18/25] clocksource/drivers/timer-imx-tpm: Specify clock name for timer-of Daniel Lezcano
2018-12-18 21:28   ` [PATCH 19/25] clocksource/drivers/riscv_timer: Provide the sched_clock Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 20/25] clocksource/drivers/riscv: Change name riscv_timer to timer-riscv Daniel Lezcano
2018-12-18 21:28     ` Daniel Lezcano
2018-12-18 21:28   ` [PATCH 21/25] clocksource/drivers/rockchip: Change name rockchip_timer to timer-rockchip Daniel Lezcano
2018-12-18 21:28   ` [PATCH 22/25] clocksource/drivers/tegra20: Change name tegra20_timer to timer-tegra20 Daniel Lezcano
2018-12-18 21:28   ` [PATCH 23/25] clocksource/drivers/sun4i: Change name sun4i_timer to timer-sun4i Daniel Lezcano
2018-12-18 21:28   ` [PATCH 24/25] clocksource/drivers/meson6: Change name meson6_timer timer-meson6 Daniel Lezcano
2018-12-18 21:28   ` [PATCH 25/25] clocksource/drivers/rda: Add clock driver for RDA8810PL SoC Daniel Lezcano

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