From 0a32eadd13ab0d2d57149cf62f3a005e688bfa64 Mon Sep 17 00:00:00 2001
From: Flavio Ceolin <flavio.ceolin@intel.com>
Date: Wed, 17 Nov 2021 21:50:08 -0800
Subject: [PATCH] pm: Account device pm state lock

Do not execute pm operations on devices that the device pm state is
locked.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
---
 include/pm/device.h        | 3 +++
 subsys/pm/device.c         | 7 ++++++-
 subsys/pm/device_runtime.c | 5 +++++
 subsys/pm/pm.c             | 4 ++--
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/pm/device.h b/include/pm/device.h
index e81148c4cc2..f9412aa4cbc 100644
--- a/include/pm/device.h
+++ b/include/pm/device.h
@@ -298,6 +298,7 @@ const char *pm_device_state_str(enum pm_device_state state);
  * @retval -EALREADY If device is already at the requested state.
  * @retval -EBUSY If device is changing its state.
  * @retval -ENOSYS If device does not support PM.
+ * @retval -EPERM If device has power state locked.
  * @retval Errno Other negative errno on failure.
  */
 __deprecated int pm_device_state_set(const struct device *dev,
@@ -418,6 +419,8 @@ bool pm_device_wakeup_is_capable(const struct device *dev);
  * system power management or device runtime power
  * management until unlocked.
  *
+ * @note The given device should not have device runtime enabled.
+ *
  * @see pm_device_state_unlock
  *
  * @param dev Device instance.
diff --git a/subsys/pm/device.c b/subsys/pm/device.c
index 6a8324ce71d..942bba71906 100644
--- a/subsys/pm/device.c
+++ b/subsys/pm/device.c
@@ -6,6 +6,7 @@
 
 #include <device.h>
 #include <pm/device.h>
+#include <pm/device_runtime.h>
 
 #include <logging/log.h>
 LOG_MODULE_REGISTER(pm_device, CONFIG_PM_DEVICE_LOG_LEVEL);
@@ -35,6 +36,10 @@ int pm_device_state_set(const struct device *dev,
 		return -ENOSYS;
 	}
 
+	if (pm_device_state_is_locked(dev)) {
+		return -EPERM;
+	}
+
 	switch (state) {
 	case PM_DEVICE_STATE_SUSPENDED:
 		if (pm->state == PM_DEVICE_STATE_SUSPENDED) {
@@ -246,7 +251,7 @@ void pm_device_state_lock(const struct device *dev)
 {
 	struct pm_device *pm = dev->pm;
 
-	if (pm != NULL) {
+	if ((pm != NULL) && !pm_device_runtime_is_enabled(dev)) {
 		atomic_set_bit(&pm->flags, PM_DEVICE_FLAG_STATE_LOCKED);
 	}
 }
diff --git a/subsys/pm/device_runtime.c b/subsys/pm/device_runtime.c
index 371138ba3c5..74b65bda352 100644
--- a/subsys/pm/device_runtime.c
+++ b/subsys/pm/device_runtime.c
@@ -172,6 +172,10 @@ void pm_device_runtime_enable(const struct device *dev)
 
 	SYS_PORT_TRACING_FUNC_ENTER(pm, device_runtime_enable, dev);
 
+	if (pm_device_state_is_locked(dev)) {
+		goto end;
+	}
+
 	if (!k_is_pre_kernel()) {
 		(void)k_mutex_lock(&pm->lock, K_FOREVER);
 	}
@@ -195,6 +199,7 @@ unlock:
 		k_mutex_unlock(&pm->lock);
 	}
 
+end:
 	SYS_PORT_TRACING_FUNC_EXIT(pm, device_runtime_enable, dev);
 }
 
diff --git a/subsys/pm/pm.c b/subsys/pm/pm.c
index 0dc09130439..c58b0213192 100644
--- a/subsys/pm/pm.c
+++ b/subsys/pm/pm.c
@@ -56,8 +56,8 @@ static int pm_suspend_devices(void)
 		 * ignore busy devices, wake up source and devices with
 		 * runtime PM enabled.
 		 */
-		if (pm_device_is_busy(dev) ||
-		    pm_device_wakeup_is_enabled(dev) ||
+		if (pm_device_is_busy(dev) || pm_device_state_is_locked(dev)
+		    || pm_device_wakeup_is_enabled(dev) ||
 		    ((dev->pm != NULL) && pm_device_runtime_is_enabled(dev))) {
 			continue;
 		}