mailbox: qcom-ipcc: Log the pending interrupt during resume

Enable logging of the pending interrupt that triggered device wakeup. This
logging information helps to debug IRQs that cause periodic device wakeups
by printing the detailed information of pending IPCC interrupts.

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 be understood that the client here is
IPCC_CLIENT_MPSS and the signal was IPCC_MPROC_SIGNAL_SMP2P.
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Prasad Sodagudi <quic_psodagud@quicinc.com>
Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/qcom-ipcc.c

@@ -255,6 +255,24 @@ static int qcom_ipcc_setup_mbox(struct qcom_ipcc *ipcc,
 	return devm_mbox_controller_register(dev, mbox);
 }
 
+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_dbg(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));
+
+	return 0;
+}
+
 static int qcom_ipcc_probe(struct platform_device *pdev)
 {
 	struct qcom_ipcc *ipcc;
@@ -325,6 +343,10 @@ 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,
@@ -332,6 +354,7 @@ static struct platform_driver qcom_ipcc_driver = {
 		.name = "qcom-ipcc",
 		.of_match_table = qcom_ipcc_of_match,
 		.suppress_bind_attrs = true,
+		.pm = pm_sleep_ptr(&qcom_ipcc_dev_pm_ops),
 	},
 };