From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date: Fri, 18 Oct 2013 20:14:45 +0000 (+0200)
Subject: Merge branch 'pm-sleep-next' into linux-next
X-Git-Tag: next-20131024~79^2~4
X-Git-Url: https://git.kernelconcepts.de/?a=commitdiff_plain;h=b16cb5620809872e0657d8e632d27c850bb79fa5;hp=5129ec1ff652cbe4d189dc5f336f8cbe654d6f23;p=karo-tx-linux.git

Merge branch 'pm-sleep-next' into linux-next

* pm-sleep-next:
  PM / Sleep: Detect device suspend/resume lockup and log event
---

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 9f098a82cf04..ee039afe9078 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -30,6 +30,8 @@
 #include <linux/suspend.h>
 #include <trace/events/power.h>
 #include <linux/cpuidle.h>
+#include <linux/timer.h>
+
 #include "../base.h"
 #include "power.h"
 
@@ -390,6 +392,71 @@ 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 -------------------------*/
 
 /**
@@ -576,6 +643,7 @@ 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);
@@ -584,6 +652,7 @@ 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);
 
 	/*
@@ -642,6 +711,7 @@ 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);
@@ -1060,6 +1130,7 @@ 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);
 
@@ -1083,6 +1154,7 @@ 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) {
@@ -1139,6 +1211,7 @@ 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);
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index d444c4e834f4..2fac9cc79b3d 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -178,6 +178,22 @@ config PM_SLEEP_DEBUG
 	def_bool y
 	depends on PM_DEBUG && PM_SLEEP
 
+config DPM_WATCHDOG
+	bool "Device suspend/resume watchdog"
+	depends on PM_DEBUG && PSTORE
+	---help---
+	  Sets up a watchdog timer to capture drivers that are
+	  locked up attempting to suspend/resume a device.
+	  A detected lockup causes system panic with message
+	  captured in pstore device for inspection in subsequent
+	  boot session.
+
+config DPM_WATCHDOG_TIMEOUT
+	int "Watchdog timeout in seconds"
+	range 1 120
+	default 12
+	depends on DPM_WATCHDOG
+
 config PM_TRACE
 	bool
 	help