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media: st_rc: Don't stay on an IRQ handler forever 

As warned by smatch:
	drivers/media/rc/st_rc.c:110 st_rc_rx_interrupt() warn: this loop depends on readl() succeeding

If something goes wrong at readl(), the logic will stay there
inside an IRQ code forever. This is not the nicest thing to
do :-)

So, add a timeout there, preventing staying inside the IRQ
for more than 10ms.

Acked-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2018-04-12 06:32:18 -04:00
parent ca33f8f61a
commit ee2d243d6b
1 changed files with 10 additions and 6 deletions
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16
drivers/media/rc/st_rc.c
View File

@ -96,19 +96,24 @@ static void st_rc_send_lirc_timeout(struct rc_dev *rdev)
static irqreturn_t st_rc_rx_interrupt(int irq, void *data)
{
unsigned long timeout;
unsigned int symbol, mark = 0;
struct st_rc_device *dev = data;
int last_symbol = 0;
u32 status;
u32 status, int_status;
DEFINE_IR_RAW_EVENT(ev);
if (dev->irq_wake)
pm_wakeup_event(dev->dev, 0);
status = readl(dev->rx_base + IRB_RX_STATUS);
/* FIXME: is 10ms good enough ? */
timeout = jiffies + msecs_to_jiffies(10);
do {
status = readl(dev->rx_base + IRB_RX_STATUS);
if (!(status & (IRB_FIFO_NOT_EMPTY | IRB_OVERFLOW)))
break;
while (status & (IRB_FIFO_NOT_EMPTY | IRB_OVERFLOW)) {
u32 int_status = readl(dev->rx_base + IRB_RX_INT_STATUS);
int_status = readl(dev->rx_base + IRB_RX_INT_STATUS);
if (unlikely(int_status & IRB_RX_OVERRUN_INT)) {
/* discard the entire collection in case of errors! */
ir_raw_event_reset(dev->rdev);
@ -148,8 +153,7 @@ static irqreturn_t st_rc_rx_interrupt(int irq, void *data)
}
last_symbol = 0;
status = readl(dev->rx_base + IRB_RX_STATUS);
}
} while (time_is_after_jiffies(timeout));
writel(IRB_RX_INTS, dev->rx_base + IRB_RX_INT_CLEAR);