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[v2,0/1] pinctrl: ocelot: fix system hang on level based interrupts

Message ID 20241012105743.12450-1-matsievskiysv@gmail.com
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Series pinctrl: ocelot: fix system hang on level based interrupts | expand

Message

Sergey Matsievskiy Oct. 12, 2024, 10:57 a.m. UTC 
Fix system hang in case of GPIO pin interrupt configured in level mode
and the parent controller configured in edge mode.
Observed on Jaguar2 VSC7448 connected to MAX3421.

v2:
 - Change commit description
 - Add Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

v1:
Link: https://lore.kernel.org/linux-mips/20241006181310.181309-1-matsievskiysv@gmail.com/

Sergey Matsievskiy (1):
  pinctrl: ocelot: fix system hang on level based interrupts

 drivers/pinctrl/pinctrl-ocelot.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Linus Walleij Oct. 12, 2024, 8:04 p.m. UTC | #1 
On Sat, Oct 12, 2024 at 12:58 PM Sergey Matsievskiy
<matsievskiysv@gmail.com> wrote:

> The current implementation only calls chained_irq_enter() and
> chained_irq_exit() if it detects pending interrupts.
>
> ```
> for (i = 0; i < info->stride; i++) {
>         uregmap_read(info->map, id_reg + 4 * i, &reg);
>         if (!reg)
>                 continue;
>
>         chained_irq_enter(parent_chip, desc);
> ```
>
> However, in case of GPIO pin configured in level mode and the parent
> controller configured in edge mode, GPIO interrupt might be lowered by the
> hardware. In the result, if the interrupt is short enough, the parent
> interrupt is still pending while the GPIO interrupt is cleared;
> chained_irq_enter() never gets called and the system hangs trying to
> service the parent interrupt.
>
> Moving chained_irq_enter() and chained_irq_exit() outside the for loop
> ensures that they are called even when GPIO interrupt is lowered by the
> hardware.
>
> The similar code with chained_irq_enter() / chained_irq_exit() functions
> wrapping interrupt checking loop may be found in many other drivers:
> ```
> grep -r -A 10 chained_irq_enter drivers/pinctrl
> ```
>
> Signed-off-by: Sergey Matsievskiy <matsievskiysv@gmail.com>
> Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Patch applied and tagged for stable!

Yours,
Linus Walleij
Andy Shevchenko Oct. 13, 2024, 7:07 p.m. UTC | #2 
On Sat, Oct 12, 2024 at 01:57:43PM +0300, Sergey Matsievskiy wrote:

...

> The similar code with chained_irq_enter() / chained_irq_exit() functions
> wrapping interrupt checking loop may be found in many other drivers:
> ```
> grep -r -A 10 chained_irq_enter drivers/pinctrl
> ```

Side note: `git grep ...` is much much faster if you have a Git tree at hand.
Sergey Matsievskiy Oct. 14, 2024, 4:56 a.m. UTC | #3 
On Sat, Oct 12, 2024 at 10:04:30PM +0200, Linus Walleij wrote:
> Patch applied and tagged for stable!

Awesome, thanks!

--
Sergey Matsievskiy
Sergey Matsievskiy Oct. 14, 2024, 5:06 a.m. UTC | #4 
On Sun, Oct 13, 2024 at 10:07:04PM +0300, Andy Shevchenko wrote:
> Side note: `git grep ...` is much much faster if you have a Git tree at hand.

Thanks for the tip! I usually use ripgrep, but git grep has some interesting
features.