4 files changed, 125 insertions, 6 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 6ca5cdf63849..3b44c201ddad 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -25,6 +25,7 @@
 #include <linux/resume-trace.h>
 #include <linux/interrupt.h>
 #include <linux/sched.h>
+#include <linux/async.h>
 
 #include "../base.h"
 #include "power.h"
@@ -42,6 +43,7 @@
 LIST_HEAD(dpm_list);
 
 static DEFINE_MUTEX(dpm_list_mtx);
+static pm_message_t pm_transition;
 
 /*
  * Set once the preparation of devices for a PM transition has started, reset
@@ -56,6 +58,7 @@ static bool transition_started;
 void device_pm_init(struct device *dev)
 {
         dev->power.status = DPM_ON;
+        init_completion(&dev->power.completion);
         pm_runtime_init(dev);
 }
 
@@ -111,6 +114,7 @@ void device_pm_remove(struct device *dev)
         pr_debug("PM: Removing info for %s:%s\n",
                  dev->bus ? dev->bus->name : "No Bus",
                  kobject_name(&dev->kobj));
+        complete_all(&dev->power.completion);
         mutex_lock(&dpm_list_mtx);
         list_del_init(&dev->power.entry);
         mutex_unlock(&dpm_list_mtx);
@@ -188,6 +192,31 @@ static void initcall_debug_report(struct device *dev, ktime_t calltime,
 }
 
 /**
+ * dpm_wait - Wait for a PM operation to complete.
+ * @dev: Device to wait for.
+ * @async: If unset, wait only if the device's power.async_suspend flag is set.
+ */
+static void dpm_wait(struct device *dev, bool async)
+{
+        if (!dev)
+                return;
+
+        if (async || dev->power.async_suspend)
+                wait_for_completion(&dev->power.completion);
+}
+
+static int dpm_wait_fn(struct device *dev, void *async_ptr)
+{
+        dpm_wait(dev, *((bool *)async_ptr));
+        return 0;
+}
+
+static void dpm_wait_for_children(struct device *dev, bool async)
+{
+       device_for_each_child(dev, &async, dpm_wait_fn);
+}
+
+/**
  * pm_op - Execute the PM operation appropriate for given PM event.
  * @dev: Device to handle.
  * @ops: PM operations to choose from.
@@ -466,17 +495,19 @@ static int legacy_resume(struct device *dev, int (*cb)(struct device *dev))
 }
 
 /**
- * device_resume - Execute "resume" callbacks for given device.
+ * __device_resume - Execute "resume" callbacks for given device.
  * @dev: Device to handle.
  * @state: PM transition of the system being carried out.
+ * @async: If true, the device is being resumed asynchronously.
  */
-static int device_resume(struct device *dev, pm_message_t state)
+static int __device_resume(struct device *dev, pm_message_t state, bool async)
 {
         int error = 0;
 
         TRACE_DEVICE(dev);
         TRACE_RESUME(0);
 
+        dpm_wait(dev->parent, async);
         down(&dev->sem);
 
         if (dev->bus) {
@@ -511,11 +542,36 @@ static int device_resume(struct device *dev, pm_message_t state)
         }
  End:
         up(&dev->sem);
+        complete_all(&dev->power.completion);
 
         TRACE_RESUME(error);
         return error;
 }
 
+static void async_resume(void *data, async_cookie_t cookie)
+{
+        struct device *dev = (struct device *)data;
+        int error;
+
+        error = __device_resume(dev, pm_transition, true);
+        if (error)
+                pm_dev_err(dev, pm_transition, " async", error);
+        put_device(dev);
+}
+
+static int device_resume(struct device *dev)
+{
+        INIT_COMPLETION(dev->power.completion);
+
+        if (dev->power.async_suspend && !pm_trace_is_enabled()) {
+                get_device(dev);
+                async_schedule(async_resume, dev);
+                return 0;
+        }
+
+        return __device_resume(dev, pm_transition, false);
+}
+
 /**
  * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
  * @state: PM transition of the system being carried out.
@@ -530,6 +586,7 @@ static void dpm_resume(pm_message_t state)
 
         INIT_LIST_HEAD(&list);
         mutex_lock(&dpm_list_mtx);
+        pm_transition = state;
         while (!list_empty(&dpm_list)) {
                 struct device *dev = to_device(dpm_list.next);
 
@@ -540,7 +597,7 @@ static void dpm_resume(pm_message_t state)
                         dev->power.status = DPM_RESUMING;
                         mutex_unlock(&dpm_list_mtx);
 
-                        error = device_resume(dev, state);
+                        error = device_resume(dev);
 
                         mutex_lock(&dpm_list_mtx);
                         if (error)
@@ -555,6 +612,7 @@ static void dpm_resume(pm_message_t state)
         }
         list_splice(&list, &dpm_list);
         mutex_unlock(&dpm_list_mtx);
+        async_synchronize_full();
         dpm_show_time(starttime, state, NULL);
 }
 
@@ -732,17 +790,24 @@ static int legacy_suspend(struct device *dev, pm_message_t state,
         return error;
 }
 
+static int async_error;
+
 /**
  * device_suspend - Execute "suspend" callbacks for given device.
  * @dev: Device to handle.
  * @state: PM transition of the system being carried out.
+ * @async: If true, the device is being suspended asynchronously.
  */
-static int device_suspend(struct device *dev, pm_message_t state)
+static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 {
         int error = 0;
 
+        dpm_wait_for_children(dev, async);
         down(&dev->sem);
 
+        if (async_error)
+                goto End;
+
         if (dev->class) {
                 if (dev->class->pm) {
                         pm_dev_dbg(dev, state, "class ");
@@ -773,12 +838,44 @@ static int device_suspend(struct device *dev, pm_message_t state)
                         error = legacy_suspend(dev, state, dev->bus->suspend);
                 }
         }
+
+        if (!error)
+                dev->power.status = DPM_OFF;
+
  End:
         up(&dev->sem);
+        complete_all(&dev->power.completion);
 
         return error;
 }
 
+static void async_suspend(void *data, async_cookie_t cookie)
+{
+        struct device *dev = (struct device *)data;
+        int error;
+
+        error = __device_suspend(dev, pm_transition, true);
+        if (error) {
+                pm_dev_err(dev, pm_transition, " async", error);
+                async_error = error;
+        }
+
+        put_device(dev);
+}
+
+static int device_suspend(struct device *dev)
+{
+        INIT_COMPLETION(dev->power.completion);
+
+        if (dev->power.async_suspend) {
+                get_device(dev);
+                async_schedule(async_suspend, dev);
+                return 0;
+        }
+
+        return __device_suspend(dev, pm_transition, false);
+}
+
 /**
  * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
  * @state: PM transition of the system being carried out.
@@ -791,13 +888,15 @@ static int dpm_suspend(pm_message_t state)
 
         INIT_LIST_HEAD(&list);
         mutex_lock(&dpm_list_mtx);
+        pm_transition = state;
+        async_error = 0;
         while (!list_empty(&dpm_list)) {
                 struct device *dev = to_device(dpm_list.prev);
 
                 get_device(dev);
                 mutex_unlock(&dpm_list_mtx);
 
-                error = device_suspend(dev, state);
+                error = device_suspend(dev);
 
                 mutex_lock(&dpm_list_mtx);
                 if (error) {
@@ -805,13 +904,17 @@ static int dpm_suspend(pm_message_t state)
                         put_device(dev);
                         break;
                 }
-                dev->power.status = DPM_OFF;
                 if (!list_empty(&dev->power.entry))
                         list_move(&dev->power.entry, &list);
                 put_device(dev);
+                if (async_error)
+                        break;
         }
         list_splice(&list, dpm_list.prev);
         mutex_unlock(&dpm_list_mtx);
+        async_synchronize_full();
+        if (!error)
+                error = async_error;
         if (!error)
                 dpm_show_time(starttime, state, NULL);
         return error;
diff --git a/include/linux/device.h b/include/linux/device.h
index a62799f2ab00..70adc5f3f50a 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -472,6 +472,12 @@ static inline int device_is_registered(struct device *dev)
         return dev->kobj.state_in_sysfs;
 }
 
+static inline void device_enable_async_suspend(struct device *dev)
+{
+        if (dev->power.status == DPM_ON)
+                dev->power.async_suspend = true;
+}
+
 void driver_init(void);
 
 /*
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 25b1eca8049d..9c16cd20fc96 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -26,6 +26,7 @@
 #include <linux/spinlock.h>
 #include <linux/wait.h>
 #include <linux/timer.h>
+#include <linux/completion.h>
 
 /*
  * Callbacks for platform drivers to implement.
@@ -412,9 +413,11 @@ struct dev_pm_info {
         pm_message_t            power_state;
         unsigned int            can_wakeup:1;
         unsigned int            should_wakeup:1;
+        unsigned                async_suspend:1;
         enum dpm_state          status;         /* Owned by the PM core */
 #ifdef CONFIG_PM_SLEEP
         struct list_head        entry;
+        struct completion       completion;
 #endif
 #ifdef CONFIG_PM_RUNTIME
         struct timer_list       suspend_timer;
diff --git a/include/linux/resume-trace.h b/include/linux/resume-trace.h
index c9ba2fdf807d..bc8c3881c729 100644
--- a/include/linux/resume-trace.h
+++ b/include/linux/resume-trace.h
@@ -6,6 +6,11 @@
 
 extern int pm_trace_enabled;
 
+static inline int pm_trace_is_enabled(void)
+{
+       return pm_trace_enabled;
+}
+
 struct device;
 extern void set_trace_device(struct device *);
 extern void generate_resume_trace(const void *tracedata, unsigned int user);
@@ -17,6 +22,8 @@ extern void generate_resume_trace(const void *tracedata, unsigned int user);
 
 #else
 
+static inline int pm_trace_is_enabled(void) { return 0; }
+
 #define TRACE_DEVICE(dev) do { } while (0)
 #define TRACE_RESUME(dev) do { } while (0)