[PATCH v2] firmware: imx: scu: ensure wakeup procedure calls pm_system_wakeup()

[Xiaolei Wang]

There will still be mu irq in the suspend stage, for
example, in imx8. When the system enters the suspend
state, the GPIO enters the pad wakeup state. Calling
pm_system_wakeup() at this time will cause the system
suspend to terminate, so when it is set to wakeup, call
pm_system_wakeup(), through rtcwake -s 10 -v -m freeze
verification.

mxc_gpio_noirq_suspend
     mxc_gpio_set_pad_wakeup
         mbox_send_message
              imx_mu_isr
                 imx_mu_generic_rxdb

Fixes: 0caf847975b2 ("firmware: imx: make sure MU irq can wake up system from suspend mode")
Signed-off-by: Xiaolei Wang <xiaolei.wang at windriver.com>
---

Changes in v2:
- Fix warning: 'imx_scu_pm_ops' defined but not used [-Wunused-const-variable=] and etested it

 drivers/firmware/imx/imx-scu-irq.c |  4 +++-
 drivers/firmware/imx/imx-scu.c     | 21 +++++++++++++++++++++
 include/linux/firmware/imx/sci.h   |  1 +
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
index 6125cccc9ba7..099a1f50d995 100644
--- a/drivers/firmware/imx/imx-scu-irq.c
+++ b/drivers/firmware/imx/imx-scu-irq.c
@@ -20,6 +20,7 @@
 #define IMX_SC_IRQ_NUM_GROUP	9
 
 static u32 mu_resource_id;
+int scu_suspend;
 
 struct imx_sc_msg_irq_get_status {
 	struct imx_sc_rpc_msg hdr;
@@ -109,7 +110,8 @@ static void imx_scu_irq_work_handler(struct work_struct *work)
 			scu_irq_wakeup[i].wakeup_src = irq_status;
 		}
 
-		pm_system_wakeup();
+		if (scu_suspend)
+			pm_system_wakeup();
 		imx_scu_irq_notifier_call_chain(irq_status, &i);
 	}
 }
diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c
index 1dd4362ef9a3..aae430b70fd5 100644
--- a/drivers/firmware/imx/imx-scu.c
+++ b/drivers/firmware/imx/imx-scu.c
@@ -342,15 +342,36 @@ static int imx_scu_probe(struct platform_device *pdev)
 	return devm_of_platform_populate(dev);
 }
 
+
+
 static const struct of_device_id imx_scu_match[] = {
 	{ .compatible = "fsl,imx-scu", },
 	{ /* Sentinel */ }
 };
+static int __maybe_unused imx_scu_suspend_noirq(struct device *dev)
+{
+	scu_suspend = true;
+
+	return 0;
+}
+
+static int __maybe_unused imx_scu_resume_noirq(struct device *dev)
+{
+	scu_suspend = false;
+
+	return 0;
+};
+
+static const struct dev_pm_ops imx_scu_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_scu_suspend_noirq,
+				      imx_scu_resume_noirq)
+};
 
 static struct platform_driver imx_scu_driver = {
 	.driver = {
 		.name = "imx-scu",
 		.of_match_table = imx_scu_match,
+		.pm = &imx_scu_pm_ops,
 	},
 	.probe = imx_scu_probe,
 };
diff --git a/include/linux/firmware/imx/sci.h b/include/linux/firmware/imx/sci.h
index df17196df5ff..244df9c7629d 100644
--- a/include/linux/firmware/imx/sci.h
+++ b/include/linux/firmware/imx/sci.h
@@ -17,6 +17,7 @@
 #include <linux/firmware/imx/svc/rm.h>
 
 #if IS_ENABLED(CONFIG_IMX_SCU)
+extern int scu_suspend;
 int imx_scu_enable_general_irq_channel(struct device *dev);
 int imx_scu_irq_register_notifier(struct notifier_block *nb);
 int imx_scu_irq_unregister_notifier(struct notifier_block *nb);
-- 
2.25.1