diff options
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/sun4i_timer.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/drivers/clocksource/sun4i_timer.c b/drivers/clocksource/sun4i_timer.c index 8e9c6513645..7123f654ce7 100644 --- a/drivers/clocksource/sun4i_timer.c +++ b/drivers/clocksource/sun4i_timer.c @@ -38,6 +38,20 @@ static void __iomem *timer_base; +/* + * When we disable a timer, we need to wait at least for 2 cycles of + * the timer source clock. We will use for that the clocksource timer + * that is already setup and runs at the same frequency than the other + * timers, and we never will be disabled. + */ +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) + cpu_relax(); +} + static void sun4i_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *clk) { @@ -63,9 +77,14 @@ static void sun4i_clkevt_mode(enum clock_event_mode mode, static int sun4i_clkevt_next_event(unsigned long evt, struct clock_event_device *unused) { - u32 u = readl(timer_base + TIMER_CTL_REG(0)); - writel(evt, timer_base + TIMER_CNTVAL_REG(0)); - writel(u | TIMER_CTL_ENABLE | TIMER_CTL_AUTORELOAD, + u32 val = readl(timer_base + TIMER_CTL_REG(0)); + writel(val & ~TIMER_CTL_ENABLE, timer_base + TIMER_CTL_REG(0)); + sun4i_clkevt_sync(); + + writel(evt, timer_base + TIMER_INTVAL_REG(0)); + + val = readl(timer_base + TIMER_CTL_REG(0)); + writel(val | TIMER_CTL_ENABLE | TIMER_CTL_AUTORELOAD, timer_base + TIMER_CTL_REG(0)); return 0; |