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Subject: Re: [PATCH v2] mailbox: qcom-ipcc: Log the pending interrupt during
 resume
To:     Manivannan Sadhasivam <mani@kernel.org>
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>
References: <1652251404-30562-1-git-send-email-quic_sibis@quicinc.com>
 <20220512074312.GA35848@thinkpad>
From:   Sibi Sankar <quic_sibis@quicinc.com>
Message-ID: <5b8aa653-5af8-a54f-b7bd-4d758eac9019@quicinc.com>
Date:   Thu, 12 May 2022 15:08:43 +0530
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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.

-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
>>
>