clear the status bit if the mask register doesn't prevent
the chip level irq from being asserted
OR in the following sequence, there will be irq storm happens:
1) interrupt is triggered;
2) another thread disables it(the mask bit is set);
3) _Then_ the interrupt thread is not ACKed(the status bit is not cleared),
and it's ignored;
4) if the irq is still asserted because of the uncleared status bit,
the irq storm happens;
Signed-off-by: Yi Zhang <[email protected]>
---
drivers/base/regmap/regmap-irq.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index d10456f..0784cf4 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -61,7 +61,7 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
{
struct regmap_irq_chip_data *d = irq_data_get_irq_chip_data(data);
struct regmap *map = d->map;
- int i, ret;
+ int i, j, ret, bits_length;
u32 reg;
if (d->chip->runtime_pm) {
@@ -105,6 +105,30 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
"Failed to sync wakes in %x: %d\n",
reg, ret);
}
+
+ if (!d->chip->init_ack_masked)
+ continue;
+ /*
+ * Ack all the masked interrupts uncondictionly,
+ * OR if there is masked interrupt which hasn't been Acked,
+ * it'll be ignored in irq handler, then may introduce irq storm
+ */
+ if (d->chip->ack_base) {
+ reg = d->chip->ack_base +
+ (i * map->reg_stride * d->irq_reg_stride);
+
+ bits_length = d->map->format.val_bytes * BITS_PER_BYTE;
+ for (j = 0; j < bits_length; j++) {
+ d->mask_buf[i] &= (0x1 << j);
+ if (!d->mask_buf[i])
+ ret = regmap_update_bits(d->map, reg,
+ (0x1 << j), 0);
+ if (ret != 0)
+ dev_err(d->map->dev, "Failed to ack 0x%x: %d\n",
+ reg, ret);
+ }
+ /* no need to sync status_buf, update in irq handler */
+ }
}
if (d->chip->runtime_pm)
--
1.7.9.5
On Tue, Oct 15, 2013 at 01:03:58PM +0800, Yi Zhang wrote:
> + bits_length = d->map->format.val_bytes * BITS_PER_BYTE;
> + for (j = 0; j < bits_length; j++) {
> + d->mask_buf[i] &= (0x1 << j);
> + if (!d->mask_buf[i])
> + ret = regmap_update_bits(d->map, reg,
> + (0x1 << j), 0);
> + if (ret != 0)
> + dev_err(d->map->dev, "Failed to ack 0x%x: %d\n",
> + reg, ret);
I don't entirely understand this code - what's the loop doing? It
looks like it's trying to acknowledge things bit by bit but it's doing
this by updating mask_buf so it looks like it'll corrupt the set of
masked interrupts. After the zeroth iteration any bits other than bit 0
should get cleared by the &= (0x1 << j). I'd have expected to just
write mask_buf back or something similar.
It's possible I'm missing something here but if that is the case perhaps
some comments would be good.
2013/10/15 Mark Brown <[email protected]>:
> On Tue, Oct 15, 2013 at 01:03:58PM +0800, Yi Zhang wrote:
>
>> + bits_length = d->map->format.val_bytes * BITS_PER_BYTE;
>> + for (j = 0; j < bits_length; j++) {
>> + d->mask_buf[i] &= (0x1 << j);
Yes, this line is wrong, I shouldn't change the mask_buf; I'll change it;
my fault; sorry;
>> + if (!d->mask_buf[i])
>> + ret = regmap_update_bits(d->map, reg,
>> + (0x1 << j), 0);
>> + if (ret != 0)
>> + dev_err(d->map->dev, "Failed to ack 0x%x: %d\n",
>> + reg, ret);
>
> I don't entirely understand this code - what's the loop doing? It
> looks like it's trying to acknowledge things bit by bit but it's doing
> this by updating mask_buf so it looks like it'll corrupt the set of
> masked interrupts. After the zeroth iteration any bits other than bit 0
> should get cleared by the &= (0x1 << j). I'd have expected to just
> write mask_buf back or something similar.
>
> It's possible I'm missing something here but if that is the case perhaps
> some comments would be good.