[PATCH V2] clockevents/drivers/mtk: Fix spurious interrupt leading to crash

Daniel Lezcano
2015-08-24T21:57:30Z

After analysis done by Yingjoe Chen, the timer appears to have a pending
interrupt when it is enabled.

Fix this by acknowledging the pending interrupt when enabling the timer
interrupt.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/clocksource/mtk_timer.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
index 4cd16fb..505f53d 100644
--- a/drivers/clocksource/mtk_timer.c
+++ b/drivers/clocksource/mtk_timer.c
@@ -156,14 +156,6 @@ static irqreturn_t mtk_timer_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}

-static void mtk_timer_global_reset(struct mtk_clock_event_device *evt)
-{
- /* Disable all interrupts */
- writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
- /* Acknowledge all interrupts */
- writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
-}
-
static void
mtk_timer_setup(struct mtk_clock_event_device *evt, u8 timer, u8 option)
{
@@ -183,6 +175,12 @@ static void mtk_timer_enable_irq(struct mtk_clock_event_device *evt, u8 timer)
{
u32 val;

+ /* Disable all interrupts */
+ writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
+
+ /* Acknowledge all spurious pending interrupts */
+ writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
+
val = readl(evt->gpt_base + GPT_IRQ_EN_REG);
writel(val | GPT_IRQ_ENABLE(timer),
evt->gpt_base + GPT_IRQ_EN_REG);
@@ -232,8 +230,6 @@ static void __init mtk_timer_init(struct device_node *node)
}
rate = clk_get_rate(clk);

- mtk_timer_global_reset(evt);
-
if (request_irq(evt->dev.irq, mtk_timer_interrupt,
IRQF_TIMER | IRQF_IRQPOLL, "mtk_timer", evt)) {
pr_warn("failed to setup irq %d\n", evt->dev.irq);
--
1.9.1