1 files changed, 78 insertions, 2 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 10c3510d72a9..e3219dfd736c 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -31,6 +31,8 @@
 #include <trace/events/power.h>
 #include <linux/cpufreq.h>
 #include <linux/cpuidle.h>
+#include <linux/timer.h>
+
 #include "../base.h"
 #include "power.h"
 
@@ -391,6 +393,71 @@ static int dpm_run_callback(pm_callback_t cb, struct device *dev,
         return error;
 }
 
+#ifdef CONFIG_DPM_WATCHDOG
+struct dpm_watchdog {
+        struct device           *dev;
+        struct task_struct      *tsk;
+        struct timer_list       timer;
+};
+
+#define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
+        struct dpm_watchdog wd
+
+/**
+ * dpm_watchdog_handler - Driver suspend / resume watchdog handler.
+ * @data: Watchdog object address.
+ *
+ * Called when a driver has timed out suspending or resuming.
+ * There's not much we can do here to recover so panic() to
+ * capture a crash-dump in pstore.
+ */
+static void dpm_watchdog_handler(unsigned long data)
+{
+        struct dpm_watchdog *wd = (void *)data;
+
+        dev_emerg(wd->dev, "**** DPM device timeout ****\n");
+        show_stack(wd->tsk, NULL);
+        panic("%s %s: unrecoverable failure\n",
+                dev_driver_string(wd->dev), dev_name(wd->dev));
+}
+
+/**
+ * dpm_watchdog_set - Enable pm watchdog for given device.
+ * @wd: Watchdog. Must be allocated on the stack.
+ * @dev: Device to handle.
+ */
+static void dpm_watchdog_set(struct dpm_watchdog *wd, struct device *dev)
+{
+        struct timer_list *timer = &wd->timer;
+
+        wd->dev = dev;
+        wd->tsk = current;
+
+        init_timer_on_stack(timer);
+        /* use same timeout value for both suspend and resume */
+        timer->expires = jiffies + HZ * CONFIG_DPM_WATCHDOG_TIMEOUT;
+        timer->function = dpm_watchdog_handler;
+        timer->data = (unsigned long)wd;
+        add_timer(timer);
+}
+
+/**
+ * dpm_watchdog_clear - Disable suspend/resume watchdog.
+ * @wd: Watchdog to disable.
+ */
+static void dpm_watchdog_clear(struct dpm_watchdog *wd)
+{
+        struct timer_list *timer = &wd->timer;
+
+        del_timer_sync(timer);
+        destroy_timer_on_stack(timer);
+}
+#else
+#define DECLARE_DPM_WATCHDOG_ON_STACK(wd)
+#define dpm_watchdog_set(x, y)
+#define dpm_watchdog_clear(x)
+#endif
+
 /*------------------------- Resume routines -------------------------*/
 
 /**
@@ -578,6 +645,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
         pm_callback_t callback = NULL;
         char *info = NULL;
         int error = 0;
+        DECLARE_DPM_WATCHDOG_ON_STACK(wd);
 
         TRACE_DEVICE(dev);
         TRACE_RESUME(0);
@@ -586,6 +654,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
                 goto Complete;
 
         dpm_wait(dev->parent, async);
+        dpm_watchdog_set(&wd, dev);
         device_lock(dev);
 
         /*
@@ -644,6 +713,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
 
  Unlock:
         device_unlock(dev);
+        dpm_watchdog_clear(&wd);
 
  Complete:
         complete_all(&dev->power.completion);
@@ -689,7 +759,7 @@ void dpm_resume(pm_message_t state)
         async_error = 0;
 
         list_for_each_entry(dev, &dpm_suspended_list, power.entry) {
-                INIT_COMPLETION(dev->power.completion);
+                reinit_completion(&dev->power.completion);
                 if (is_async(dev)) {
                         get_device(dev);
                         async_schedule(async_resume, dev);
@@ -1063,6 +1133,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
         pm_callback_t callback = NULL;
         char *info = NULL;
         int error = 0;
+        DECLARE_DPM_WATCHDOG_ON_STACK(wd);
 
         dpm_wait_for_children(dev, async);
 
@@ -1086,6 +1157,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
         if (dev->power.syscore)
                 goto Complete;
 
+        dpm_watchdog_set(&wd, dev);
         device_lock(dev);
 
         if (dev->pm_domain) {
@@ -1142,6 +1214,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
         }
 
         device_unlock(dev);
+        dpm_watchdog_clear(&wd);
 
  Complete:
         complete_all(&dev->power.completion);
@@ -1167,7 +1240,7 @@ static void async_suspend(void *data, async_cookie_t cookie)
 
 static int device_suspend(struct device *dev)
 {
-        INIT_COMPLETION(dev->power.completion);
+        reinit_completion(&dev->power.completion);
 
         if (pm_async_enabled && dev->power.async_suspend) {
                 get_device(dev);
@@ -1280,6 +1353,9 @@ static int device_prepare(struct device *dev, pm_message_t state)
 
         device_unlock(dev);
 
+        if (error)
+                pm_runtime_put(dev);
+
         return error;
 }