[PATCH v2 02/15] clocksource: orion: Use atomic access for shared registers
Daniel Lezcano
daniel.lezcano at linaro.org
Tue Jan 21 04:57:37 EST 2014
On 01/21/2014 10:12 AM, Ezequiel Garcia wrote:
> Replace the driver-specific thread-safe shared register API
> by the recently introduced atomic_io_clear_set().
>
> Signed-off-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
Hi Ezequiel,
in the future, put me in Cc when modifying files in clocksource that
will make my life easier to track the changes.
Thanks.
-- Daniel
> ---
> drivers/clocksource/time-orion.c | 28 ++++++++++------------------
> 1 file changed, 10 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/clocksource/time-orion.c b/drivers/clocksource/time-orion.c
> index 9c7f018..3f14e56 100644
> --- a/drivers/clocksource/time-orion.c
> +++ b/drivers/clocksource/time-orion.c
> @@ -35,20 +35,6 @@
> #define ORION_ONESHOT_MAX 0xfffffffe
>
> static void __iomem *timer_base;
> -static DEFINE_SPINLOCK(timer_ctrl_lock);
> -
> -/*
> - * Thread-safe access to TIMER_CTRL register
> - * (shared with watchdog timer)
> - */
> -void orion_timer_ctrl_clrset(u32 clr, u32 set)
> -{
> - spin_lock(&timer_ctrl_lock);
> - writel((readl(timer_base + TIMER_CTRL) & ~clr) | set,
> - timer_base + TIMER_CTRL);
> - spin_unlock(&timer_ctrl_lock);
> -}
> -EXPORT_SYMBOL(orion_timer_ctrl_clrset);
> /*
> * Free-running clocksource handling.
> @@ -68,7 +54,8 @@ static int orion_clkevt_next_event(unsigned long delta,
> {
> /* setup and enable one-shot timer */
> writel(delta, timer_base + TIMER1_VAL);
> - orion_timer_ctrl_clrset(TIMER1_RELOAD_EN, TIMER1_EN);
> + atomic_io_modify(timer_base + TIMER_CTRL,
> + TIMER1_RELOAD_EN | TIMER1_EN, TIMER1_EN);
I am not convinced this change is worth.
Could you elaborate the race the spinlock should prevent ?
>
> return 0;
> }
> @@ -80,10 +67,13 @@ static void orion_clkevt_mode(enum clock_event_mode mode,
> /* setup and enable periodic timer at 1/HZ intervals */
> writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD);
> writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL);
> - orion_timer_ctrl_clrset(0, TIMER1_RELOAD_EN | TIMER1_EN);
> + atomic_io_modify(timer_base + TIMER_CTRL,
> + TIMER1_RELOAD_EN | TIMER1_EN,
> + TIMER1_RELOAD_EN | TIMER1_EN);
> } else {
> /* disable timer */
> - orion_timer_ctrl_clrset(TIMER1_RELOAD_EN | TIMER1_EN, 0);
> + atomic_io_modify(timer_base + TIMER_CTRL,
> + TIMER1_RELOAD_EN | TIMER1_EN, 0);
> }
> }
>
> @@ -131,7 +121,9 @@ static void __init orion_timer_init(struct device_node *np)
> /* setup timer0 as free-running clocksource */
> writel(~0, timer_base + TIMER0_VAL);
> writel(~0, timer_base + TIMER0_RELOAD);
> - orion_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | TIMER0_EN);
> + atomic_io_modify(timer_base + TIMER_CTRL,
> + TIMER0_RELOAD_EN | TIMER0_EN,
> + TIMER0_RELOAD_EN | TIMER0_EN);
> clocksource_mmio_init(timer_base + TIMER0_VAL, "orion_clocksource",
> clk_get_rate(clk), 300, 32,
> clocksource_mmio_readl_down);
>
--
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