linux-kernel - [PATCH 3/4] Add physical count arch timer support for clocksource in ARMv7.

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Message-Id: <1378968687-8200-4-git-send-email-cinifr@gmail.com>
Date:	Thu, 12 Sep 2013 14:51:26 +0800
From:	Fan Rong <cinifr@...il.com>
To:	coosty@....com, maxime.ripard@...e-electrons.com,
	daniel.lezcano@...aro.org, linux@....linux.org.uk,
	tglx@...utronix.de, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, mark.rutland@....com,
	pawel.moll@....co, rob.herring@...xeda.com,
	linux-sunxi@...glegroups.com
Cc:	Fan Rong <cinifr@...il.com>
Subject: [PATCH 3/4] Add physical count arch timer support for clocksource in ARMv7.

Signed-off-by: Fan Rong <cinifr@...il.com>
---
 arch/arm/include/asm/arch_timer.h    |   11 +++++++++++
 drivers/clocksource/Kconfig          |    8 ++++++++
 drivers/clocksource/arm_arch_timer.c |   10 +++++++++-
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h
index 5665134..24c904a 100644
--- a/arch/arm/include/asm/arch_timer.h
+++ b/arch/arm/include/asm/arch_timer.h
@@ -87,6 +87,17 @@ static inline u64 arch_counter_get_cntvct(void)
 	return cval;
 }
 
+static inline u64 arch_counter_get_cntpct(void)
+{
+	u64 cval;
+
+	isb();
+	asm volatile("mrrc p15, 0, %Q0, %R0, c14" : "=r" (cval));
+	return cval;
+}
+
+
+
 static inline void arch_counter_set_user_access(void)
 {
 	u32 cntkctl;
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 41c6946..a4981d2 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -109,3 +109,11 @@ config VF_PIT_TIMER
 	bool
 	help
 	  Support for Period Interrupt Timer on Freescale Vybrid Family SoCs.
+menu "Clock Source"
+
+config ARM_ARCH_TIMER_USE_PHYCNT
+	bool "Use Physical Count Timer"
+	depends on ARM_ARCH_TIMER
+	help
+          If bootloader dont set Virtual Offset register,Physical Count Timer is needed to replace Virtual Count Timer.
+endmenu
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index fbd9ccd..884e4d1 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -372,7 +372,11 @@ static u64 arch_counter_get_cntvct_mem(void)
  * to exist on arm64. arm doesn't use this before DT is probed so even
  * if we don't have the cp15 accessors we won't have a problem.
  */
-u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
+#ifdef CONFIG_ARM_ARCH_TIMER_USE_PHYCNT
+	u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntpct;
+#else
+	u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
+#endif
 
 static cycle_t arch_counter_read(struct clocksource *cs)
 {
@@ -410,7 +414,11 @@ static void __init arch_counter_register(unsigned type)
 
 	/* Register the CP15 based counter if we have one */
 	if (type & ARCH_CP15_TIMER)
+#ifdef CONFIG_ARM_ARCH_TIMER_USE_PHYCNT
+		arch_timer_read_counter = arch_counter_get_cntpct;
+#else
 		arch_timer_read_counter = arch_counter_get_cntvct;
+#endif
 	else
 		arch_timer_read_counter = arch_counter_get_cntvct_mem;
 
-- 
1.7.9.5

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