pm: device_runtime: Allow to use system wq

Add an option to use the system work queue instead of defining
its own queue for asynchronous API.

Signed-off-by: Flavio Ceolin <[email protected]>

Author: ceolin

include/zephyr/pm/device.h

@@ -170,7 +170,8 @@ struct pm_device {
 	struct k_sem lock;
 	/** Event var to listen to the sync request events */
 	struct k_event event;
-#if defined(CONFIG_PM_DEVICE_RUNTIME_ASYNC) || defined(__DOXYGEN__)
+#if (defined(CONFIG_PM_DEVICE_RUNTIME_ASYNC) && !defined(CONFIG_PM_DEVICE_RUNTIME_ASYNC_USE_SYSTEM_WQ))
+	|| defined(__DOXYGEN__)
 	/** Work object for asynchronous calls */
 	struct k_work_delayable work;
 #endif /* CONFIG_PM_DEVICE_RUNTIME_ASYNC */

subsys/pm/Kconfig

@@ -110,6 +110,13 @@ config PM_DEVICE_RUNTIME_ASYNC
 	  in the power management device runtime.
 
 if PM_DEVICE_RUNTIME_ASYNC
+config PM_DEVICE_RUNTIME_USE_SYSTEM_WQ
+	bool "Use the system workqueue"
+	default n
+	help
+	  When this option is enabled the power management subsystem will
+	  use the system worqueue instead of defining its own queue.
+
 config PM_DEVICE_RUNTIME_WQ_STACK_SIZE
 	int "Stack size for pm runtime async workqueue"
 	default 1024
@@ -119,8 +126,8 @@ config PM_DEVICE_RUNTIME_WQ_STACK_SIZE
 
 config PM_DEVICE_RUNTIME_WQ_PRIO
 	int "PM device runtime workqueue priority. Should be pre-emptible."
+	default SYSTEM_WORKQUEUE_PRIORITY if PM_DEVICE_RUNTIME_USE_SYSTEM_WQ
 	default 0
-	range 0 NUM_PREEMPT_PRIORITIES
 
 config PM_DEVICE_RUNTIME_WQ_INIT_PRIO
 	int "PM device runtime workqueue init priority"

subsys/pm/device_runtime.c

@@ -21,8 +21,10 @@ LOG_MODULE_DECLARE(pm_device, CONFIG_PM_DEVICE_LOG_LEVEL);
 #endif
 
 #ifdef CONFIG_PM_DEVICE_RUNTIME_ASYNC
+#ifndef CONFIG_PM_DEVICE_RUNTIME_USE_SYSTEM_WQ
 K_THREAD_STACK_DEFINE(pm_device_runtime_stack, CONFIG_PM_DEVICE_RUNTIME_WQ_STACK_SIZE);
 static struct k_work_q pm_device_runtime_wq;
+#endif /* !CONFIG_PM_DEVICE_RUNTIME_USE_SYSTEM_WQ */
 #endif /* CONFIG_PM_DEVICE_RUNTIME_ASYNC */
 
 #define EVENT_STATE_ACTIVE	BIT(PM_DEVICE_STATE_ACTIVE)
@@ -86,7 +88,11 @@ static int runtime_suspend(const struct device *dev, bool async,
 		/* queue suspend */
 #ifdef CONFIG_PM_DEVICE_RUNTIME_ASYNC
 		pm->base.state = PM_DEVICE_STATE_SUSPENDING;
+#ifdef CONFIG_PM_DEVICE_RUNTIME_USE_SYSTEM_WQ
+		(void)k_work_schedule(&pm->work, delay);
+#else
 		(void)k_work_schedule_for_queue(&pm_device_runtime_wq, &pm->work, delay);
+#endif /* CONFIG_PM_DEVICE_RUNTIME_USE_SYSTEM_WQ */
 #endif /* CONFIG_PM_DEVICE_RUNTIME_ASYNC */
 	} else {
 		/* suspend now */
@@ -592,6 +598,7 @@ int pm_device_runtime_usage(const struct device *dev)
 }
 
 #ifdef CONFIG_PM_DEVICE_RUNTIME_ASYNC
+#ifndef CONFIG_PM_DEVICE_RUNTIME_USE_SYSTEM_WQ
 
 static int pm_device_runtime_wq_init(void)
 {
@@ -608,4 +615,5 @@ static int pm_device_runtime_wq_init(void)
 
 SYS_INIT(pm_device_runtime_wq_init, POST_KERNEL, CONFIG_PM_DEVICE_RUNTIME_WQ_INIT_PRIO);
 
+#endif /* !CONFIG_PM_DEVICE_RUNTIME_USE_SYSTEM_WQ */
 #endif /* CONFIG_PM_DEVICE_RUNTIME_ASYNC */

tests/subsys/pm/device_runtime_api/testcase.yaml

@@ -10,6 +10,11 @@ tests:
     - native_sim
     extra_configs:
     - CONFIG_TEST_PM_DEVICE_ISR_SAFE=y
+  pm.device_runtime.async_system_wq.api:
+    platform_allow:
+    - native_sim
+    extra_configs:
+    - CONFIG_PM_DEVICE_RUNTIME_ASYNC_USE_SYSTEM_WQ=y
   pm.device_runtime.async_disabled.api:
     platform_allow:
     - native_sim