From 834c3d2c4b6b6b1fdeb4d3c24253210769d1dea0 Mon Sep 17 00:00:00 2001
From: Zhang Jiejing <jiejing.zhang@freescale.com>
Date: Mon, 22 Nov 2010 17:14:32 +0800
Subject: ENGR00133978 PM: add time sensitive debug function to suspend &
 resume

There was some driver is slow on suspend/resume,
but some embeded system like eReader,Cellphone
are time sensitive,this commit will report the slow
driver on suspend/resume, the default value is 500us(0.5ms)

Also, the threshold can be change by modify
'/sys/power/device_suspend_time_threshold' to change the threshold,
it is in microsecond.

The output is like:

PM: device platform:soc-audio.2 suspend too slow, takes          606.696 msecs
PM: device platform:mxc_sdc_fb.1 suspend too slow, takes         7.708 msecs

the default state of suspend driver is default off,
if you want to debug the suspend time, echo time in
microsecond(u Second) to /sys/powe/device_suspend_time_threshold

eg: I want to know which driver suspend & resume takes
more that 0.5 ms (500 us), you can just :

ehco 500 > /sys/power/device_suspend_time_threshold

Signed-off-by: Zhang Jiejing <jiejing.zhang@freescale.com>
---
 drivers/base/power/main.c  | 39 ++++++++++++++++++++++++++++++++++++++-
 drivers/base/power/power.h |  4 ++++
 2 files changed, 42 insertions(+), 1 deletion(-)

(limited to 'drivers/base')

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 06f09bf89cb2..f1e1a5b8fb04 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -179,6 +179,39 @@ static void initcall_debug_report(struct device *dev, ktime_t calltime,
 			error, (unsigned long long)ktime_to_ns(delta) >> 10);
 	}
 }
+#ifdef CONFIG_SUSPEND_DEVICE_TIME_DEBUG
+static void suspend_time_debug_start(ktime_t *start)
+{
+	*start = ktime_get();
+}
+
+static void suspend_time_debug_report(const char *name, struct device *dev,
+				      ktime_t starttime)
+{
+	ktime_t rettime;
+	s64 usecs64;
+	int usecs;
+
+	if (!dev->driver)
+		return;
+
+	rettime = ktime_get();
+	usecs64 = ktime_to_us(ktime_sub(rettime, starttime));
+	usecs = usecs64;
+	if (usecs == 0)
+		usecs = 1;
+
+	if (device_suspend_time_threshold
+	    && usecs > device_suspend_time_threshold)
+		pr_info("PM: device %s:%s %s too slow, it takes \t %ld.%03ld msecs\n",
+			dev->bus->name, dev_name(dev), name,
+			usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
+}
+#else
+static void suspend_time_debug_start(ktime_t *start) {}
+static void suspend_time_debug_report(const char *name, struct device *dev,
+				      ktime_t starttime) {}
+#endif /* CONFIG_SUSPEND_DEVICE_TIME_DEBUG */
 
 /**
  * dpm_wait - Wait for a PM operation to complete.
@@ -216,7 +249,7 @@ static int pm_op(struct device *dev,
 		 pm_message_t state)
 {
 	int error = 0;
-	ktime_t calltime;
+	ktime_t calltime, starttime;
 
 	calltime = initcall_debug_start(dev);
 
@@ -224,13 +257,17 @@ static int pm_op(struct device *dev,
 #ifdef CONFIG_SUSPEND
 	case PM_EVENT_SUSPEND:
 		if (ops->suspend) {
+			suspend_time_debug_start(&starttime);
 			error = ops->suspend(dev);
+			suspend_time_debug_report("suspend", dev, starttime);
 			suspend_report_result(ops->suspend, error);
 		}
 		break;
 	case PM_EVENT_RESUME:
 		if (ops->resume) {
+			suspend_time_debug_start(&starttime);
 			error = ops->resume(dev);
+			suspend_time_debug_report("resume", dev, starttime);
 			suspend_report_result(ops->resume, error);
 		}
 		break;
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index f2a25f18fde7..51b585a4e9d9 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -10,6 +10,10 @@ static inline void pm_runtime_remove(struct device *dev) {}
 
 #endif /* !CONFIG_PM_RUNTIME */
 
+#ifdef CONFIG_SUSPEND_DEVICE_TIME_DEBUG
+extern int device_suspend_time_threshold;
+#endif
+
 #ifdef CONFIG_PM_SLEEP
 
 /* kernel/power/main.c */
-- 
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