clocksource: sun4i: Report the minimum tick that we can program
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 <maxime.ripard@free-electrons.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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 @@
{
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 @@
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 @@
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);