linux-kernel - Re: [PATCH 4/9] mfd: pm8xxx: disassociate old virq if hwirq mapping already exists

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Date:   Wed, 30 Jan 2019 13:31:16 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Brian Masney <masneyb@...tation.org>
Cc:     linus.walleij@...aro.org, sboyd@...nel.org,
        bjorn.andersson@...aro.org, andy.gross@...aro.org,
        marc.zyngier@....com, 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 4/9] mfd: pm8xxx: disassociate old virq if hwirq mapping
 already exists

Thomas,

On Fri, 25 Jan 2019, Brian Masney wrote:

> 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.

I guess that's okay.  Would quite like a second opinion though.

> This change was not tested on any actual hardware, however the same
> change was made to spmi-pmic-arb.c and tested on a LG Nexus 5
> (hammerhead) phone.
> 
> Signed-off-by: Brian Masney <masneyb@...tation.org>
> ---
>  drivers/mfd/qcom-pm8xxx.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/mfd/qcom-pm8xxx.c b/drivers/mfd/qcom-pm8xxx.c
> index a976890c4019..97b931465601 100644
> --- a/drivers/mfd/qcom-pm8xxx.c
> +++ b/drivers/mfd/qcom-pm8xxx.c
> @@ -387,6 +387,11 @@ static void pm8xxx_irq_domain_map(struct pm_irq_chip *chip,
>  				  irq_hw_number_t hwirq, unsigned int type)
>  {
>  	irq_flow_handler_t handler;
> +	unsigned int old_virq;
> +
> +	old_virq = irq_find_mapping(domain, hwirq);
> +	if (old_virq)
> +		irq_domain_disassociate(domain, old_virq);
>  
>  	if (type & IRQ_TYPE_EDGE_BOTH)
>  		handler = handle_edge_irq;

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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