linux-kernel - Re: [RESEND PATCH v3 02/10] spmi: pmic-arb: do not ack and clear peripheral interrupts in cleanup

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Date:   Thu, 2 Dec 2021 02:39:53 +0000
From:   Bryan O'Donoghue <bryan.odonoghue@...aro.org>
To:     Fenglin Wu <quic_fenglinw@...cinc.com>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        sboyd@...nel.org
Cc:     collinsd@...eaurora.org, subbaram@...eaurora.org,
        tglx@...utronix.de, maz@...nel.org
Subject: Re: [RESEND PATCH v3 02/10] spmi: pmic-arb: do not ack and clear
 peripheral interrupts in cleanup_irq

On 02/12/2021 00:00, Fenglin Wu wrote:
> From: Subbaraman Narayanamurthy <subbaram@...eaurora.org>
> 
> Currently, cleanup_irq() is invoked when a peripheral's interrupt
> fires and there is no mapping present in the interrupt domain of
> spmi interrupt controller.
> 
> The cleanup_irq clears the arbiter bit, clears the pmic interrupt
> and disables it at the pmic in that order. The last disable in
> cleanup_irq races with request_irq() in that it stomps over the
> enable issued by request_irq. Fix this by not writing to the pmic
> in cleanup_irq. The latched bit will be left set in the pmic,
> which will not send us more interrupts even if the enable bit
> stays enabled.
> 
> When a client wants to request an interrupt, use the activate
> callback on the irq_domain to clear latched bit. This ensures
> that the latched, if set due to the above changes in cleanup_irq
> or when the bootloader leaves it set, gets cleaned up, paving way
> for upcoming interrupts to trigger.
> 
> With this, there is a possibility of unwanted triggering of
> interrupt right after the latched bit is cleared - the interrupt
> may be left enabled too. To avoid that, clear the enable first
> followed by clearing the latched bit in the activate callback.
> 
> Signed-off-by: Subbaraman Narayanamurthy <subbaram@...eaurora.org>
> [collinsd@...eaurora.org: fix merge conflict]
> Signed-off-by: David Collins <collinsd@...eaurora.org>
> Signed-off-by: Fenglin Wu <quic_fenglinw@...cinc.com>
> ---
>   drivers/spmi/spmi-pmic-arb.c | 15 +++++----------
>   1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/spmi/spmi-pmic-arb.c b/drivers/spmi/spmi-pmic-arb.c
> index da629cc..ce7ae99 100644
> --- a/drivers/spmi/spmi-pmic-arb.c
> +++ b/drivers/spmi/spmi-pmic-arb.c
> @@ -492,16 +492,6 @@ static void cleanup_irq(struct spmi_pmic_arb *pmic_arb, u16 apid, int id)
>   	dev_err_ratelimited(&pmic_arb->spmic->dev, "%s apid=%d sid=0x%x per=0x%x irq=%d\n",
>   			__func__, apid, sid, per, id);
>   	writel_relaxed(irq_mask, pmic_arb->ver_ops->irq_clear(pmic_arb, apid));
> -
> -	if (pmic_arb_write_cmd(pmic_arb->spmic, SPMI_CMD_EXT_WRITEL, sid,
> -			(per << 8) + QPNPINT_REG_LATCHED_CLR, &irq_mask, 1))
> -		dev_err_ratelimited(&pmic_arb->spmic->dev, "failed to ack irq_mask = 0x%x for ppid = %x\n",
> -				irq_mask, ppid);spmi: pmic-arb: cleanup unrequested irqs
> -
> -	if (pmic_arb_write_cmd(pmic_arb->spmic, SPMI_CMD_EXT_WRITEL, sid,
> -			       (per << 8) + QPNPINT_REG_EN_CLR, &irq_mask, 1))
> -		dev_err_ratelimited(&pmic_arb->spmic->dev, "failed to ack irq_mask = 0x%x for ppid = %x\n",
> -				irq_mask, ppid);
>   }
>   
>   static int periph_interrupt(struct spmi_pmic_arb *pmic_arb, u16 apid)
> @@ -674,6 +664,7 @@ static int qpnpint_irq_domain_activate(struct irq_domain *domain,
>   	u16 apid = hwirq_to_apid(d->hwirq);
>   	u16 sid = hwirq_to_sid(d->hwirq);
>   	u16 irq = hwirq_to_irq(d->hwirq);
> +	u8 buf;
>   
>   	if (pmic_arb->apid_data[apid].irq_ee != pmic_arb->ee) {
>   		dev_err(&pmic_arb->spmic->dev, "failed to xlate sid = %#x, periph = %#x, irq = %u: ee=%u but owner=%u\n",
> @@ -682,6 +673,10 @@ static int qpnpint_irq_domain_activate(struct irq_domain *domain,
>   		return -ENODEV;
>   	}
>   
> +	buf = BIT(irq);
> +	qpnpint_spmi_write(d, QPNPINT_REG_EN_CLR, &buf, 1);
> +	qpnpint_spmi_write(d, QPNPINT_REG_LATCHED_CLR, &buf, 1);
> +
>   	return 0;
>   }
>   
> 

Shouldn't this have a

Fixes: 6bc546e71e50 ("spmi: pmic-arb: cleanup unrequested irqs")
Fixes: 02abec3616c1 ("spmi: pmic-arb: rename pa_xx to pmic_arb_xx and 
other cleanup")

so we know to backport as necessary

---
bod