We need to wait for at least 2 clock cycles whenever we reprogram our clockevent timer. Report that the minimum number of ticks we can handle is 3 ticks, and remove 3 ticks to the interval programmed to reflect this.
Signed-off-by: Maxime Ripard <[email protected]> --- drivers/clocksource/sun4i_timer.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/clocksource/sun4i_timer.c b/drivers/clocksource/sun4i_timer.c index 8ead025..46008f9 100644 --- a/drivers/clocksource/sun4i_timer.c +++ b/drivers/clocksource/sun4i_timer.c @@ -37,6 +37,8 @@ #define TIMER_INTVAL_REG(val) (0x10 * (val) + 0x14) #define TIMER_CNTVAL_REG(val) (0x10 * (val) + 0x18) +#define TIMER_SYNC_TICKS 3 + static void __iomem *timer_base; static u32 ticks_per_jiffy; @@ -50,7 +52,7 @@ static void sun4i_clkevt_sync(void) { u32 old = readl(timer_base + TIMER_CNTVAL_REG(1)); - while ((old - readl(timer_base + TIMER_CNTVAL_REG(1))) < 3) + while ((old - readl(timer_base + TIMER_CNTVAL_REG(1))) < TIMER_SYNC_TICKS) cpu_relax(); } @@ -104,7 +106,7 @@ static int sun4i_clkevt_next_event(unsigned long evt, struct clock_event_device *unused) { sun4i_clkevt_time_stop(0); - sun4i_clkevt_time_setup(0, evt); + sun4i_clkevt_time_setup(0, evt - TIMER_SYNC_TICKS); sun4i_clkevt_time_start(0, false); return 0; @@ -187,8 +189,8 @@ static void __init sun4i_timer_init(struct device_node *node) sun4i_clockevent.cpumask = cpumask_of(0); - clockevents_config_and_register(&sun4i_clockevent, rate, 0x1, - 0xffffffff); + clockevents_config_and_register(&sun4i_clockevent, rate, + TIMER_SYNC_TICKS, 0xffffffff); } CLOCKSOURCE_OF_DECLARE(sun4i, "allwinner,sun4i-timer", sun4i_timer_init); -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
