linux-kernel - Re: [PATCH v2 05/11] mfd: pm8xxx: disassociate old virq if hwirq mapping already exists

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Date:   Thu, 14 Feb 2019 21:51:26 -0800
From:   Stephen Boyd <sboyd@...nel.org>
To:     Brian Masney <masneyb@...tation.org>, andy.gross@...aro.org,
        bjorn.andersson@...aro.org, lee.jones@...aro.org,
        linus.walleij@...aro.org, marc.zyngier@....com
Cc:     tglx@...utronix.de, shawnguo@...nel.org, dianders@...omium.org,
        linux-gpio@...r.kernel.org, nicolas.dechesne@...aro.org,
        niklas.cassel@...aro.org, david.brown@...aro.org,
        robh+dt@...nel.org, mark.rutland@....com, thierry.reding@...il.com,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v2 05/11] mfd: pm8xxx: disassociate old virq if hwirq mapping already exists

Quoting Brian Masney (2019-02-07 18:16:25)
> Check to see if the hwirq is already associated with another virq on
> this IRQ domain. If so, then disassociate it before associating the
> hwirq with the new virq.
> 
> This is a temporary hack that is needed in order to not break git
> bisect for existing boards. The next patch in this series converts
> ssbi-gpio to be a hierarchical IRQ chip, then there are several patches
> to update all of the device tree files, and finally this patch will be
> reverted within the same patch series.
> 
> IRQs for ssbi-gpio are all initially setup without an IRQ hierarchy
> this driver is probed due to the interrupts property in device tree.
> Once ssbi-gpio is converted to be a hierarchical IRQ chip in the next
> patch, existing users of gpio[d]_to_irq() will call pmic_gpio_to_irq(),
> and that will use the new IRQ chip code in ssbi-gpio that sets up the
> IRQ in an IRQ hierarchy. The hwirq is now associated with two Linux
> virqs and interrupts will not work as expected. This patch corrects
> that issue.
> 
> This change was tested on an APQ8060 DragonBoard.
> 
> Signed-off-by: Brian Masney <masneyb@...tation.org>
> Tested-by: Linus Walleij <linus.walleij@...aro.org>
> ---
> Changes since v1:
> - None
> 
>  drivers/mfd/qcom-pm8xxx.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/mfd/qcom-pm8xxx.c b/drivers/mfd/qcom-pm8xxx.c
> index 8eb2528793f9..2f99a98ccee5 100644
> --- a/drivers/mfd/qcom-pm8xxx.c
> +++ b/drivers/mfd/qcom-pm8xxx.c
> @@ -380,6 +380,12 @@ static void pm8xxx_irq_domain_map(struct pm_irq_chip *chip,
>                                   struct irq_domain *domain, unsigned int irq,
>                                   irq_hw_number_t hwirq, unsigned int type)
>  {
> +       unsigned int old_virq;
> +
> +       old_virq = irq_find_mapping(domain, hwirq);
> +       if (old_virq)
> +               irq_domain_disassociate(domain, old_virq);

Is it possible to pass 'true' for the 'realloc' argument to
__irq_domain_alloc_irqs() and then this disassociate change isn't
needed?

> +
>         irq_domain_set_info(domain, irq, hwirq, chip->pm_irq_data->irq_chip,
>                             chip, handle_level_irq, NULL, NULL);
>         irq_set_noprobe(irq);