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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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