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Subject[PATCH 1/2] clocksource: arm_arch_timer: unify sched_clock init
Date
From: Rob Herring <rob.herring@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@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@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


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