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Date:   Mon, 16 May 2022 18:57:37 +0530
From:   Manivannan Sadhasivam <mani@kernel.org>
To:     Sibi Sankar <quic_sibis@quicinc.com>
Cc:     bjorn.andersson@linaro.org, jassisinghbrar@gmail.com,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        agross@kernel.org, Prasad Sodagudi <quic_psodagud@quicinc.com>
Subject: Re: [PATCH v2] mailbox: qcom-ipcc: Log the pending interrupt during
 resume
Message-ID: <20220516132737.GA5492@thinkpad>
References: <1652251404-30562-1-git-send-email-quic_sibis@quicinc.com>
 <20220512074312.GA35848@thinkpad>
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 <76a15747-b06e-e869-078f-ac4ad2e4a5ec@quicinc.com>
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On Thu, May 12, 2022 at 04:49:30PM +0530, Sibi Sankar wrote:
> 
> 
> On 5/12/22 3:29 PM, Manivannan Sadhasivam wrote:
> > On Thu, May 12, 2022 at 03:08:43PM +0530, Sibi Sankar wrote:
> > > 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@quicinc.com>
> > > > > 
> > > > > 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@quicinc.com>
> > > > > Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
> > > > > ---
> > > > > 
> > > > > 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.
> > > 
> > 
> > Right but that information is only required for debugging the periodic wakeups.
> > And that's not going to be useful for an end user.
> 
> I would consider this an extension to "Resume caused by IRQ xx, xxxx"

May I know from where it is coming? I couldn't grep it.

> print that we get to identify the wake up source. That's the reasoning
> behind marking it as dev_info (being able to nail down random wakeups is
> just an added advantage). That said I'll re-spin it with dbg if that's
> the consensus.
> 

I'll leave it up to Jassi to decide. But this patch looks good to me otherwise.

Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>

Thanks,
Mani

> > 
> > Thanks,
> > Mani
> > 
> > > -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
> > > > > 
> > > > 
> > 

-- 
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