• Sergey Matsievskiy's avatar
    pinctrl: ocelot: fix system hang on level based interrupts · 93b8ddc5
    Sergey Matsievskiy authored
    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
    ```
    
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarSergey Matsievskiy <matsievskiysv@gmail.com>
    Reviewed-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
    Link: https://lore.kernel.org/20241012105743.12450-2-matsievskiysv@gmail.comSigned-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
    93b8ddc5
pinctrl-ocelot.c 57.9 KB