[PATCH v2 02/15] clocksource: orion: Use atomic access for shared registers
From: Daniel Lezcano <hidden>
Date: 2014-01-21 09:57:37
Also in:
linux-devicetree, linux-watchdog
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 <redacted>
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
quoted hunk
--- 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 ?
quoted hunk
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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