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>

2 files changed, 61 insertions, 0 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 87f4d24b55b0..c1a820a36861 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -7,6 +7,31 @@ config SUSPEND
 	  powered and thus its contents are preserved, such as the
 	  suspend-to-RAM state (e.g. the ACPI S3 state).
 
+config PM_TEST_SUSPEND
+	bool "Test suspend/resume and wakealarm during bootup"
+	depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
+	---help---
+	This option will let you suspend your machine during bootup, and
+	make it wake up a few seconds later using an RTC wakeup alarm.
+	Enable this with a kernel parameter like "test_suspend=mem".
+
+	You probably want to have your system's RTC driver statically
+	linked, ensuring that it's available when this test runs.
+
+config SUSPEND_DEVICE_TIME_DEBUG
+        bool "Warnning device suspend/resume takes too much time"
+	depends on SUSPEND && PM_DEBUG
+	default n
+	---help---
+	This option will enable a timing function to check device
+        suspend time consumption, If the device takes more time that
+        the threshold(default 0.5 ms), it will print the device and
+        bus name on the console.  You can change the threshold
+        on-the-fly by modify /sys/power/time_threshold the time unit
+        is in microsecond.
+
+	This options only for debug proprose, If in doubt, say N.
+
 config SUSPEND_FREEZER
 	bool "Enable freezer for suspend to RAM/standby" \
 		if ARCH_WANTS_FREEZER_CONTROL || BROKEN
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 2981af4ce7cb..b7d0e301e43b 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -297,12 +297,48 @@ power_attr(pm_trace_dev_match);
 
 #endif /* CONFIG_PM_TRACE */
 
+#ifdef CONFIG_SUSPEND_DEVICE_TIME_DEBUG
+/*
+ * threshold of device suspend time consumption in microsecond(0.5ms), the
+ * driver suspend/resume time longer than this threshold will be
+ * print to console, 0 to disable */
+int device_suspend_time_threshold;
+
+static ssize_t
+device_suspend_time_threshold_show(struct kobject *kobj,
+				   struct kobj_attribute *attr, char *buf)
+{
+	if (device_suspend_time_threshold == 0)
+		return sprintf(buf, "off\n");
+	else
+		return sprintf(buf, "%d usecs\n",
+			       device_suspend_time_threshold);
+}
+
+static ssize_t
+device_suspend_time_threshold_store(struct kobject *kobj,
+				    struct kobj_attribute *attr,
+				    const char *buf, size_t n)
+{
+	int val;
+	if (sscanf(buf, "%d", &val) > 0) {
+		device_suspend_time_threshold = val;
+		return n;
+	}
+	return -EINVAL;
+}
+power_attr(device_suspend_time_threshold);
+#endif
+
 static struct attribute * g[] = {
 	&state_attr.attr,
 #ifdef CONFIG_PM_TRACE
 	&pm_trace_attr.attr,
 	&pm_trace_dev_match_attr.attr,
 #endif
+#ifdef CONFIG_SUSPEND_DEVICE_TIME_DEBUG
+	&device_suspend_time_threshold_attr.attr,
+#endif
 #ifdef CONFIG_PM_SLEEP
 	&pm_async_attr.attr,
 	&wakeup_count_attr.attr,