Re: [PATCH v2] mailbox: qcom-ipcc: Log the pending interrupt during resume

[Sibi Sankar]

Hey Mani,

Thanks for taking time to review the patch.

On 5/12/22 1:13 PM, Manivannan Sadhasivam wrote:
> On Wed, May 11, 2022 at 12:13:24PM +0530, Sibi Sankar wrote:
> > From: Prasad Sodagudi <quic_psodagud@xxxxxxxxxxx>
> >
> > Enable logging of the pending interrupt that triggered device wakeup. This
> > logging information helps to debug IRQs that cause periodic device wakeups
> > and prints the detailed information of pending IPCC interrupts instead of
> > the generic "Resume caused by IRQ 17, ipcc".
> >
> > Scenario: Device wakeup caused by Modem crash
> > Logs:
> > qcom-ipcc mailbox: virq: 182 triggered client-id: 2; signal-id: 2
> >
> >  From the IPCC bindings it can further understood that the client here is
> > IPCC_CLIENT_MPSS and the signal was IPCC_MPROC_SIGNAL_SMP2P.
> >
> > Signed-off-by: Prasad Sodagudi <quic_psodagud@xxxxxxxxxxx>
> > Signed-off-by: Sibi Sankar <quic_sibis@xxxxxxxxxxx>
> > ---
> >
> > V2:
> >   * Fix build error when ipcc is a module [Kernel Test Bot]
> >
> >   drivers/mailbox/qcom-ipcc.c | 27 +++++++++++++++++++++++++++
> >   1 file changed, 27 insertions(+)
> >
> > diff --git a/drivers/mailbox/qcom-ipcc.c b/drivers/mailbox/qcom-ipcc.c
> > index c5d963222014..21c071ec119c 100644
> > --- a/drivers/mailbox/qcom-ipcc.c
> > +++ b/drivers/mailbox/qcom-ipcc.c
> > @@ -254,6 +254,28 @@ static int qcom_ipcc_setup_mbox(struct qcom_ipcc *ipcc,
> >   	return devm_mbox_controller_register(dev, mbox);
> >   }
> >   
> > +#ifdef CONFIG_PM_SLEEP
>
> You don't need this guard anymore. Please see below.

ack

> > +static int qcom_ipcc_pm_resume(struct device *dev)
> > +{
> > +	struct qcom_ipcc *ipcc = dev_get_drvdata(dev);
> > +	u32 hwirq;
> > +	int virq;
> > +
> > +	hwirq = readl(ipcc->base + IPCC_REG_RECV_ID);
> > +	if (hwirq == IPCC_NO_PENDING_IRQ)
> > +		return 0;
> > +
> > +	virq = irq_find_mapping(ipcc->irq_domain, hwirq);
> > +
> > +	dev_info(dev, "virq: %d triggered client-id: %ld; signal-id: %ld\n", virq,
> > +		 FIELD_GET(IPCC_CLIENT_ID_MASK, hwirq), FIELD_GET(IPCC_SIGNAL_ID_MASK, hwirq));
> > +
>
> Does this really need to be dev_info? This looks like a dev_dbg() material to
> me.

The whole point of the log is to catch sporadic issues like random
wakeups caused by remoteprocs through ipcc. We would just end up with
a single line identifying the client id during resume if ipcc had indeed
caused the wakeup else it wouldn't print anything.

-Sibi
> > +	return 0;
> > +}
> > +#else
> > +#define qcom_ipcc_pm_resume NULL
> > +#endif
> > +
> >   static int qcom_ipcc_probe(struct platform_device *pdev)
> >   {
> >   	struct qcom_ipcc *ipcc;
> > @@ -324,6 +346,10 @@ static const struct of_device_id qcom_ipcc_of_match[] = {
> >   };
> >   MODULE_DEVICE_TABLE(of, qcom_ipcc_of_match);
> >   
> > +static const struct dev_pm_ops qcom_ipcc_dev_pm_ops = {
> > +	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(NULL, qcom_ipcc_pm_resume)
> > +};
> > +
> >   static struct platform_driver qcom_ipcc_driver = {
> >   	.probe = qcom_ipcc_probe,
> >   	.remove = qcom_ipcc_remove,
> > @@ -331,6 +357,7 @@ static struct platform_driver qcom_ipcc_driver = {
> >   		.name = "qcom-ipcc",
> >   		.of_match_table = qcom_ipcc_of_match,
> >   		.suppress_bind_attrs = true,
> > +		.pm = &qcom_ipcc_dev_pm_ops,
>
> You can use the new pm_sleep_ptr() macro to avoid the PM_SLEEP guard.
>
> 		.pm = pm_sleep_ptr(&qcom_ipcc_dev_pm_ops),

ack

> Thanks,
> Mani
>
> >   	},
> >   };
> >   
> > --
> > 2.7.4