Re: [PATCH] gpio: tegra186: Don't set parent IRQ affinity

[Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>]

On Fri, May 7, 2021 at 12:34 PM Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
>
> When hotplugging CPUs on Tegra186 and Tegra194 errors such as the
> following are seen ...
>
>  IRQ63: set affinity failed(-22).
>  IRQ65: set affinity failed(-22).
>  IRQ66: set affinity failed(-22).
>  IRQ67: set affinity failed(-22).
>
> Looking at the /proc/interrupts the above are all interrupts associated
> with GPIOs. The reason why these error messages occur is because there
> is no 'parent_data' associated with any of the GPIO interrupts and so
> tegra186_irq_set_affinity() simply returns -EINVAL.
>
> To understand why there is no 'parent_data' it is first necessary to
> understand that in addition to the GPIO interrupts being routed to the
> interrupt controller (GIC), the interrupts for some GPIOs are also
> routed to the Tegra Power Management Controller (PMC) to wake up the
> system from low power states. In order to configure GPIO events as
> wake events in the PMC, the PMC is configured as IRQ parent domain
> for the GPIO IRQ domain. Originally the GIC was the IRQ parent domain
> of the PMC and although this was working, this started causing issues
> once commit 64a267e9a41c ("irqchip/gic: Configure SGIs as standard
> interrupts") was added, because technically, the GIC is not a parent
> of the PMC. Commit c351ab7bf2a5 ("soc/tegra: pmc: Don't create fake
> interrupt hierarchy levels") fixed this by severing the IRQ domain
> hierarchy for the Tegra GPIOs and hence, there may be no IRQ parent
> domain for the GPIOs.
>
> The GPIO controllers on Tegra186 and Tegra194 have either one or six
> interrupt lines to the interrupt controller. For GPIO controllers with
> six interrupts, the mapping of the GPIO interrupt to the controller
> interrupt is configurable within the GPIO controller. Currently a
> default mapping is used, however, it could be possible to use the
> set affinity callback for the Tegra186 GPIO driver to do something a
> bit more interesting. Currently, because interrupts for all GPIOs are
> have the same mapping and any attempts to configure the affinity for
> a given GPIO can conflict with another that shares the same IRQ, for
> now it is simpler to just remove set affinity support and this avoids
> the above warnings being seen.
>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Fixes: c4e1f7d92cd6 ("gpio: tegra186: Set affinity callback to parent")
> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> ---
>  drivers/gpio/gpio-tegra186.c | 11 -----------
>  1 file changed, 11 deletions(-)
>
> diff --git a/drivers/gpio/gpio-tegra186.c b/drivers/gpio/gpio-tegra186.c
> index 1bd9e44df718..05974b760796 100644
> --- a/drivers/gpio/gpio-tegra186.c
> +++ b/drivers/gpio/gpio-tegra186.c
> @@ -444,16 +444,6 @@ static int tegra186_irq_set_wake(struct irq_data *data, unsigned int on)
>         return 0;
>  }
>
> -static int tegra186_irq_set_affinity(struct irq_data *data,
> -                                    const struct cpumask *dest,
> -                                    bool force)
> -{
> -       if (data->parent_data)
> -               return irq_chip_set_affinity_parent(data, dest, force);
> -
> -       return -EINVAL;
> -}
> -
>  static void tegra186_gpio_irq(struct irq_desc *desc)
>  {
>         struct tegra_gpio *gpio = irq_desc_get_handler_data(desc);
> @@ -700,7 +690,6 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
>         gpio->intc.irq_unmask = tegra186_irq_unmask;
>         gpio->intc.irq_set_type = tegra186_irq_set_type;
>         gpio->intc.irq_set_wake = tegra186_irq_set_wake;
> -       gpio->intc.irq_set_affinity = tegra186_irq_set_affinity;
>
>         irq = &gpio->gpio.irq;
>         irq->chip = &gpio->intc;
> --
> 2.17.1
>

Thanks for the very descriptive commit message!

Patch applied.

Bart