[PATCH 1/2] clocksource: arm_arch_timer: unify sched_clock init

[Rob Herring]

From: Rob Herring <rob.herring at calxeda.com>

In preparation to fix initial time and suspend/resume handling, unify
the sched_clock init and implementation for arch timer on arm and arm64.

Signed-off-by: Rob Herring <rob.herring at calxeda.com>
Cc: Russell King <linux at arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will.deacon at arm.com>
Cc: John Stultz <john.stultz at linaro.org>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Stephen Boyd <sboyd at codeaurora.org>
---
 arch/arm/kernel/arch_timer.c         |   12 ------------
 arch/arm64/kernel/time.c             |   10 ----------
 drivers/clocksource/arm_arch_timer.c |   14 ++++++++++++++
 include/clocksource/arm_arch_timer.h |    1 +
 4 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index 59dcdce..df6825e 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -22,13 +22,6 @@ static unsigned long arch_timer_read_counter_long(void)
 	return arch_timer_read_counter();
 }
 
-static u32 sched_clock_mult __read_mostly;
-
-static unsigned long long notrace arch_timer_sched_clock(void)
-{
-	return arch_timer_read_counter() * sched_clock_mult;
-}
-
 static struct delay_timer arch_delay_timer;
 
 static void __init arch_timer_delay_timer_register(void)
@@ -48,11 +41,6 @@ int __init arch_timer_arch_init(void)
 
 	arch_timer_delay_timer_register();
 
-	/* Cache the sched_clock multiplier to save a divide in the hot path. */
-	sched_clock_mult = NSEC_PER_SEC / arch_timer_rate;
 	sched_clock_func = arch_timer_sched_clock;
-	pr_info("sched_clock: ARM arch timer >56 bits at %ukHz, resolution %uns\n",
-		arch_timer_rate / 1000, sched_clock_mult);
-
 	return 0;
 }
diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
index a551f88..3a369aa 100644
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -61,13 +61,6 @@ unsigned long profile_pc(struct pt_regs *regs)
 EXPORT_SYMBOL(profile_pc);
 #endif
 
-static u64 sched_clock_mult __read_mostly;
-
-unsigned long long notrace sched_clock(void)
-{
-	return arch_timer_read_counter() * sched_clock_mult;
-}
-
 int read_current_timer(unsigned long *timer_value)
 {
 	*timer_value = arch_timer_read_counter();
@@ -84,9 +77,6 @@ void __init time_init(void)
 	if (!arch_timer_rate)
 		panic("Unable to initialise architected timer.\n");
 
-	/* Cache the sched_clock multiplier to save a divide in the hot path. */
-	sched_clock_mult = NSEC_PER_SEC / arch_timer_rate;
-
 	/* Calibrate the delay loop directly */
 	lpj_fine = arch_timer_rate / HZ;
 }
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 122ff05..17ed8e4 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -266,6 +266,15 @@ static struct notifier_block arch_timer_cpu_nb __cpuinitdata = {
 	.notifier_call = arch_timer_cpu_notify,
 };
 
+static u64 sched_clock_mult __read_mostly;
+
+unsigned long long notrace arch_timer_sched_clock(void)
+{
+	return arch_timer_read_counter() * sched_clock_mult;
+}
+unsigned long long sched_clock(void) \
+	__attribute__((weak, alias("arch_timer_sched_clock")));
+
 static int __init arch_timer_register(void)
 {
 	int err;
@@ -318,6 +327,11 @@ static int __init arch_timer_register(void)
 	/* Immediately configure the timer on the boot CPU */
 	arch_timer_setup(this_cpu_ptr(arch_timer_evt));
 
+	/* Cache the sched_clock multiplier to save a divide in the hot path. */
+	sched_clock_mult = NSEC_PER_SEC / arch_timer_rate;
+	pr_info("sched_clock: ARM arch timer >56 bits at %ukHz, resolution %lluns\n",
+		arch_timer_rate / 1000, sched_clock_mult);
+
 	return 0;
 
 out_free_irq:
diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h
index e6c9c4c..ded7c77 100644
--- a/include/clocksource/arm_arch_timer.h
+++ b/include/clocksource/arm_arch_timer.h
@@ -34,6 +34,7 @@
 extern u32 arch_timer_get_rate(void);
 extern u64 (*arch_timer_read_counter)(void);
 extern struct timecounter *arch_timer_get_timecounter(void);
+extern unsigned long long notrace arch_timer_sched_clock(void);
 
 #else
 
-- 
1.7.10.4