[PATCH] pmdomain: core: Introduce device_set/get_out_band_wakeup()

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@xxxxxxx>

For some cases, a device could still wakeup the system even if its power
domain is in off state, because the device's wakeup hardware logic is
in an always-on domain.

To support this case, introduce device_set/get_out_band_wakeup() to
allow device drivers to control the behaviour in genpd for a device
that is attached to it.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---

V1:
 More discussion:
 https://lore.kernel.org/arm-scmi/20250218162045.GA15753@nxa18884-linux/T/#me83f18f001e0db51860c53d0979f1ac8deb10a12
 With "device_set_out_band_wakeup(dev, true);" in probe of driver
 drivers/usb/dwc3/dwc3-imx8mp.c, when USB power domain is in off state,
 usb could still wakeup the system.

 drivers/pmdomain/core.c   |  6 ++++--
 include/linux/pm.h        |  1 +
 include/linux/pm_wakeup.h | 17 +++++++++++++++++
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 9b2f28b34bb5..fa0d93c9078e 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -1450,7 +1450,8 @@ static int genpd_finish_suspend(struct device *dev,
 	if (ret)
 		return ret;
 
-	if (device_wakeup_path(dev) && genpd_is_active_wakeup(genpd))
+	if (device_wakeup_path(dev) && genpd_is_active_wakeup(genpd) &&
+	    !device_get_out_band_wakeup(dev))
 		return 0;
 
 	if (genpd->dev_ops.stop && genpd->dev_ops.start &&
@@ -1505,7 +1506,8 @@ static int genpd_finish_resume(struct device *dev,
 	if (IS_ERR(genpd))
 		return -EINVAL;
 
-	if (device_wakeup_path(dev) && genpd_is_active_wakeup(genpd))
+	if (device_wakeup_path(dev) && genpd_is_active_wakeup(genpd) &&
+	    !device_get_out_band_wakeup(dev))
 		return resume_noirq(dev);
 
 	genpd_lock(genpd);
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 63a8dffda787..2c1dd35c3e19 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -683,6 +683,7 @@ struct dev_pm_info {
 	bool			smart_suspend:1;	/* Owned by the PM core */
 	bool			must_resume:1;		/* Owned by the PM core */
 	bool			may_skip_resume:1;	/* Set by subsystems */
+	bool			out_band_wakeup:1;
 #else
 	bool			should_wakeup:1;
 #endif
diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index 51e0e8dd5f9e..8dee27c34c3c 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -94,6 +94,16 @@ static inline void device_set_wakeup_path(struct device *dev)
 	dev->power.wakeup_path = true;
 }
 
+static inline void device_set_out_band_wakeup(struct device *dev, bool capable)
+{
+	dev->power.out_band_wakeup = capable;
+}
+
+static inline bool device_get_out_band_wakeup(struct device *dev)
+{
+	return dev->power.out_band_wakeup;
+}
+
 /* drivers/base/power/wakeup.c */
 extern struct wakeup_source *wakeup_source_create(const char *name);
 extern void wakeup_source_destroy(struct wakeup_source *ws);
@@ -177,6 +187,13 @@ static inline bool device_wakeup_path(struct device *dev)
 
 static inline void device_set_wakeup_path(struct device *dev) {}
 
+static inline void device_set_out_band_wakeup(struct device *dev, bool capable) {}
+
+static inline bool device_get_out_band_wakeup(struct device *dev)
+{
+	return false;
+}
+
 static inline void __pm_stay_awake(struct wakeup_source *ws) {}
 
 static inline void pm_stay_awake(struct device *dev) {}
-- 
2.37.1