[PATCH v2] PM/sleep: Expose suspend stats in sysfs

[Kalesh Singh <kaleshsingh@google.com>]

Userspace can get suspend stats from the suspend stats debugfs node.
Since debugfs doesn't have stable ABI, expose suspend stats in
sysfs under /sys/power/suspend_stats.

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
---
Changes in v2:
  - Added separate show functions for last_failed_* stats, as per Greg
  - Updated ABI Documentation

 Documentation/ABI/testing/sysfs-power | 106 ++++++++++++++++++++++++++
 kernel/power/main.c                   |  97 ++++++++++++++++++++++-
 2 files changed, 201 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
index 3c5130355011..6f87b9dd384b 100644
--- a/Documentation/ABI/testing/sysfs-power
+++ b/Documentation/ABI/testing/sysfs-power
@@ -301,3 +301,109 @@ Description:
 
 		Using this sysfs file will override any values that were
 		set using the kernel command line for disk offset.
+
+What:		/sys/power/suspend_stats
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats directory contains suspend related
+		statistics.
+
+What:		/sys/power/suspend_stats/success
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/success file contains the number
+		of times entering system sleep state succeeded.
+
+What:		/sys/power/suspend_stats/fail
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/fail file contains the number
+		of times entering system sleep state failed.
+
+What:		/sys/power/suspend_stats/failed_freeze
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/failed_freeze file contains the
+		number of times freezing processes failed.
+
+What:		/sys/power/suspend_stats/failed_prepare
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/failed_prepare file contains the
+		number of times preparing all non-sysdev devices for
+		a system PM transition failed.
+
+What:		/sys/power/suspend_stats/failed_resume
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/failed_resume file contains the
+		number of times executing "resume" callbacks of
+		non-sysdev devices failed.
+
+What:		/sys/power/suspend_stats/failed_resume_early
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/failed_resume_early file contains
+		the number of times executing "early resume" callbacks
+		of devices failed.
+
+What:		/sys/power/suspend_stats/failed_resume_noirq
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/failed_resume_noirq file contains
+		the number of times executing "noirq resume" callbacks
+		of devices failed.
+
+What:		/sys/power/suspend_stats/failed_suspend
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/failed_suspend file contains
+		the number of times executing "suspend" callbacks
+		of all non-sysdev devices failed.
+
+What:		/sys/power/suspend_stats/failed_suspend_late
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/failed_suspend_late file contains
+		the number of times executing "late suspend" callbacks
+		of all devices failed.
+
+What:		/sys/power/suspend_stats/failed_suspend_noirq
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/failed_suspend_noirq file contains
+		the number of times executing "noirq suspend" callbacks
+		of all devices failed.
+
+What:		/sys/power/suspend_stats/last_failed_dev
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/last_failed_dev file contains
+		the last device for which a suspend/resume callback failed.
+
+What:		/sys/power/suspend_stats/last_failed_errno
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/last_failed_errno file contains
+		the errno of the last failed attempt at entering
+		system sleep state.
+
+What:		/sys/power/suspend_stats/last_failed_step
+Date:		July 2019
+Contact:	Kalesh Singh <kaleshsingh96@gmail.com>
+Description:
+		The /sys/power/suspend_stats/last_failed_step file contains
+		the last failed step in the suspend/resume path.
diff --git a/kernel/power/main.c b/kernel/power/main.c
index bdbd605c4215..938dc53a8b94 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -254,7 +254,6 @@ static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
 power_attr(pm_test);
 #endif /* CONFIG_PM_SLEEP_DEBUG */
 
-#ifdef CONFIG_DEBUG_FS
 static char *suspend_step_name(enum suspend_stat_step step)
 {
 	switch (step) {
@@ -275,6 +274,92 @@ static char *suspend_step_name(enum suspend_stat_step step)
 	}
 }
 
+#define suspend_attr(_name)					\
+static ssize_t _name##_show(struct kobject *kobj,		\
+		struct kobj_attribute *attr, char *buf)		\
+{								\
+	return sprintf(buf, "%d\n", suspend_stats._name);	\
+}								\
+static struct kobj_attribute _name = __ATTR_RO(_name)
+
+suspend_attr(success);
+suspend_attr(fail);
+suspend_attr(failed_freeze);
+suspend_attr(failed_prepare);
+suspend_attr(failed_suspend);
+suspend_attr(failed_suspend_late);
+suspend_attr(failed_suspend_noirq);
+suspend_attr(failed_resume);
+suspend_attr(failed_resume_early);
+suspend_attr(failed_resume_noirq);
+
+static ssize_t last_failed_dev_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	int index;
+	char *last_failed_dev = NULL;
+
+	index = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
+	index %= REC_FAILED_NUM;
+	last_failed_dev = suspend_stats.failed_devs[index];
+
+	return sprintf(buf, "%s\n", last_failed_dev);
+}
+static struct kobj_attribute last_failed_dev = __ATTR_RO(last_failed_dev);
+
+static ssize_t last_failed_errno_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	int index;
+	int last_failed_errno;
+
+	index = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
+	index %= REC_FAILED_NUM;
+	last_failed_errno = suspend_stats.errno[index];
+
+	return sprintf(buf, "%d\n", last_failed_errno);
+}
+static struct kobj_attribute last_failed_errno = __ATTR_RO(last_failed_errno);
+
+static ssize_t last_failed_step_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	int index;
+	enum suspend_stat_step step;
+	char *last_failed_step = NULL;
+
+	index = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
+	index %= REC_FAILED_NUM;
+	step = suspend_stats.failed_steps[index];
+	last_failed_step = suspend_step_name(step);
+
+	return sprintf(buf, "%s\n", last_failed_step);
+}
+static struct kobj_attribute last_failed_step = __ATTR_RO(last_failed_step);
+
+static struct attribute *suspend_attrs[] = {
+	&success.attr,
+	&fail.attr,
+	&failed_freeze.attr,
+	&failed_prepare.attr,
+	&failed_suspend.attr,
+	&failed_suspend_late.attr,
+	&failed_suspend_noirq.attr,
+	&failed_resume.attr,
+	&failed_resume_early.attr,
+	&failed_resume_noirq.attr,
+	&last_failed_dev.attr,
+	&last_failed_errno.attr,
+	&last_failed_step.attr,
+	NULL,
+};
+
+static struct attribute_group suspend_attr_group = {
+	.name = "suspend_stats",
+	.attrs = suspend_attrs,
+};
+
+#ifdef CONFIG_DEBUG_FS
 static int suspend_stats_show(struct seq_file *s, void *unused)
 {
 	int i, index, last_dev, last_errno, last_step;
@@ -794,6 +879,14 @@ static const struct attribute_group attr_group = {
 	.attrs = g,
 };
 
+static const struct attribute_group *attr_groups[] = {
+	&attr_group,
+#ifdef CONFIG_PM_SLEEP
+	&suspend_attr_group,
+#endif
+	NULL,
+};
+
 struct workqueue_struct *pm_wq;
 EXPORT_SYMBOL_GPL(pm_wq);
 
@@ -815,7 +908,7 @@ static int __init pm_init(void)
 	power_kobj = kobject_create_and_add("power", NULL);
 	if (!power_kobj)
 		return -ENOMEM;
-	error = sysfs_create_group(power_kobj, &attr_group);
+	error = sysfs_create_groups(power_kobj, attr_groups);
 	if (error)
 		return error;
 	pm_print_times_init();
-- 
2.22.0.770.g0f2c4a37fd-goog