[PATCH v7 0/3] PM / wakeup: show wakeup sources stats in sysfs

[PATCH v7 0/3] PM / wakeup: show wakeup sources stats in sysfs

[Tri Vo]

Userspace can use wakeup_sources debugfs node to plot history of suspend
blocking wakeup sources over device's boot cycle. This information can
then be used (1) for power-specific bug reporting and (2) towards
attributing battery consumption to specific processes over a period of
time.

However, debugfs doesn't have stable ABI. For this reason, create a
'struct device' to expose wakeup sources statistics in sysfs under
/sys/class/wakeup/wakeup<ID>/*.

Patch 1 and 2 do some cleanup to simplify our changes to how wakeup sources are
created. Patch 3 implements wakeup sources stats in sysfs.

Tri Vo (3):
  PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()
  PM / wakeup: Use wakeup_source_register() in wakelock.c
  PM / wakeup: Show wakeup sources stats in sysfs

 Documentation/ABI/testing/sysfs-class-wakeup |  76 +++++++++
 drivers/acpi/device_pm.c                     |   3 +-
 drivers/base/power/Makefile                  |   2 +-
 drivers/base/power/power.h                   |   9 ++
 drivers/base/power/wakeup.c                  |  59 ++++---
 drivers/base/power/wakeup_stats.c            | 161 +++++++++++++++++++
 fs/eventpoll.c                               |   4 +-
 include/linux/pm_wakeup.h                    |  21 +--
 kernel/power/autosleep.c                     |   2 +-
 kernel/power/wakelock.c                      |  32 ++--
 kernel/time/alarmtimer.c                     |   2 +-
 11 files changed, 316 insertions(+), 55 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-wakeup
 create mode 100644 drivers/base/power/wakeup_stats.c

v2:
- Updated Documentation/ABI/, as per Greg.
- Removed locks in attribute functions, as per Greg.
- Lifetimes of struct wakelock and struck wakeup_source are now different due to
  the latter embedding a refcounted kobject. Changed it so that struct wakelock
  only has a pointer to struct wakeup_source, instead of embedding it.
- Added CONFIG_PM_SLEEP_STATS that enables/disables wakeup source statistics in
  sysfs.

v3:
Changes by Greg:
- Reworked code to use 'struct device' instead of raw kobjects.
- Updated documentation file.
- Only link wakeup_stats.o when CONFIG_PM_SLEEP_STATS is enabled.
Changes by Tri:
- Reverted changes to kernel/power/wakelock.c. 'struct device' hides kobject
  operations. So no need to handle lifetimes in wakelock.c

v4:
- Added 'Co-developed-by:' and 'Tested-by:' fields to commit message.
- Moved new documentation to a separate file
  Documentation/ABI/testing/sysfs-class-wakeup, as per Greg.
- Fixed copyright header in drivers/base/power/wakeup_stats.c, as per Greg.

v5:
- Removed CONFIG_PM_SLEEP_STATS
- Used PTR_ERR_OR_ZERO instead of if(IS_ERR(...)) + PTR_ERR, reported by
  kbuild test robot <lkp@intel.com>
- Stephen reported that a call to device_init_wakeup() and writing 'enabled' to
  that device's power/wakeup file results in multiple wakeup source being
  allocated for that device.  Changed device_wakeup_enable() to check if device
  wakeup was previously enabled.
Changes by Stephen:
- Changed stats location from /sys/class/wakeup/<name>/* to
  /sys/class/wakeup/wakeup<ID>/*, where ID is an IDA-allocated integer. This
  avoids name collisions in /sys/class/wakeup/ directory.
- Added a "name" attribute to wakeup sources, and updated documentation.
- Device registering the wakeup source is now the parent of the wakeup source.
  Updated wakeup_source_register()'s signature and its callers accordingly.

v6:
- Changed stats location to /sys/class/wakeup/ws<ID>/*
- Replaced ida_simple_get()/ida_simple_remove() with ida_alloc()/ida_free() as
  the former is deprecated.
- Reverted changes to device_init_wakeup(). Rafael is preparing a patch to deal
  with extra wakeup source allocation in a separate patch.

v7:
- Removed wakeup_source_init(), wakeup_source_prepare().
- Removed duplicate wakeup source creation code from  kernel/power/wakelock.
- Moved ID allocation to wakeup source object creation time.
- Changed stats location back to /sys/class/wakeup/wakeup<ID>/*
- Remove wakeup source device's "power" attributes.

--
2.22.0.770.g0f2c4a37fd-goog

[PATCH v7 1/3] PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()

[Tri Vo]

wakeup_source_init() has no users. Remove it.

As a result, wakeup_source_prepare() is only called from
wakeup_source_create(). Merge wakeup_source_prepare() into
wakeup_source_create() and remove it.

Signed-off-by: Tri Vo <trong@android.com>
---
 drivers/base/power/wakeup.c | 33 +++++++++++++--------------------
 include/linux/pm_wakeup.h   | 11 -----------
 2 files changed, 13 insertions(+), 31 deletions(-)

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index ee31d4f8d856..3938892c8903 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -72,23 +72,6 @@ static struct wakeup_source deleted_ws = {
 	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
 };
 
-/**
- * wakeup_source_prepare - Prepare a new wakeup source for initialization.
- * @ws: Wakeup source to prepare.
- * @name: Pointer to the name of the new wakeup source.
- *
- * Callers must ensure that the @name string won't be freed when @ws is still in
- * use.
- */
-void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
-{
-	if (ws) {
-		memset(ws, 0, sizeof(*ws));
-		ws->name = name;
-	}
-}
-EXPORT_SYMBOL_GPL(wakeup_source_prepare);
-
 /**
  * wakeup_source_create - Create a struct wakeup_source object.
  * @name: Name of the new wakeup source.
@@ -96,13 +79,23 @@ EXPORT_SYMBOL_GPL(wakeup_source_prepare);
 struct wakeup_source *wakeup_source_create(const char *name)
 {
 	struct wakeup_source *ws;
+	const char *ws_name;
 
-	ws = kmalloc(sizeof(*ws), GFP_KERNEL);
+	ws = kzalloc(sizeof(*ws), GFP_KERNEL);
 	if (!ws)
-		return NULL;
+		goto err_ws;
+
+	ws_name = kstrdup_const(name, GFP_KERNEL);
+	if (!ws_name)
+		goto err_name;
+	ws->name = ws_name;
 
-	wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
 	return ws;
+
+err_name:
+	kfree(ws);
+err_ws:
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(wakeup_source_create);
 
diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index 91027602d137..c0cad2d8f800 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -81,7 +81,6 @@ static inline void device_set_wakeup_path(struct device *dev)
 }
 
 /* drivers/base/power/wakeup.c */
-extern void wakeup_source_prepare(struct wakeup_source *ws, const char *name);
 extern struct wakeup_source *wakeup_source_create(const char *name);
 extern void wakeup_source_destroy(struct wakeup_source *ws);
 extern void wakeup_source_add(struct wakeup_source *ws);
@@ -112,9 +111,6 @@ static inline bool device_can_wakeup(struct device *dev)
 	return dev->power.can_wakeup;
 }
 
-static inline void wakeup_source_prepare(struct wakeup_source *ws,
-					 const char *name) {}
-
 static inline struct wakeup_source *wakeup_source_create(const char *name)
 {
 	return NULL;
@@ -181,13 +177,6 @@ static inline void pm_wakeup_dev_event(struct device *dev, unsigned int msec,
 
 #endif /* !CONFIG_PM_SLEEP */
 
-static inline void wakeup_source_init(struct wakeup_source *ws,
-				      const char *name)
-{
-	wakeup_source_prepare(ws, name);
-	wakeup_source_add(ws);
-}
-
 static inline void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
 {
 	return pm_wakeup_ws_event(ws, msec, false);
-- 
2.22.0.770.g0f2c4a37fd-goog

[PATCH v7 2/3] PM / wakeup: Use wakeup_source_register() in wakelock.c

[Tri Vo]

kernel/power/wakelock.c duplicates wakeup source creation and
registration code from drivers/base/power/wakeup.c.

Change struct wakelock's wakeup source to a pointer and use
wakeup_source_register() function to create and register said wakeup
source. Use wakeup_source_unregister() on cleanup path.

Signed-off-by: Tri Vo <trong@android.com>
---
 kernel/power/wakelock.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
index 4210152e56f0..d1eb7fd98b64 100644
--- a/kernel/power/wakelock.c
+++ b/kernel/power/wakelock.c
@@ -27,7 +27,7 @@ static DEFINE_MUTEX(wakelocks_lock);
 struct wakelock {
 	char			*name;
 	struct rb_node		node;
-	struct wakeup_source	ws;
+	struct wakeup_source	*ws;
 #ifdef CONFIG_PM_WAKELOCKS_GC
 	struct list_head	lru;
 #endif
@@ -46,7 +46,7 @@ ssize_t pm_show_wakelocks(char *buf, bool show_active)
 
 	for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
 		wl = rb_entry(node, struct wakelock, node);
-		if (wl->ws.active == show_active)
+		if (wl->ws->active == show_active)
 			str += scnprintf(str, end - str, "%s ", wl->name);
 	}
 	if (str > buf)
@@ -112,16 +112,16 @@ static void __wakelocks_gc(struct work_struct *work)
 		u64 idle_time_ns;
 		bool active;
 
-		spin_lock_irq(&wl->ws.lock);
-		idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time));
-		active = wl->ws.active;
-		spin_unlock_irq(&wl->ws.lock);
+		spin_lock_irq(&wl->ws->lock);
+		idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws->last_time));
+		active = wl->ws->active;
+		spin_unlock_irq(&wl->ws->lock);
 
 		if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
 			break;
 
 		if (!active) {
-			wakeup_source_remove(&wl->ws);
+			wakeup_source_unregister(wl->ws);
 			rb_erase(&wl->node, &wakelocks_tree);
 			list_del(&wl->lru);
 			kfree(wl->name);
@@ -187,9 +187,15 @@ static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
 		kfree(wl);
 		return ERR_PTR(-ENOMEM);
 	}
-	wl->ws.name = wl->name;
-	wl->ws.last_time = ktime_get();
-	wakeup_source_add(&wl->ws);
+
+	wl->ws = wakeup_source_register(wl->name);
+	if (!wl->ws) {
+		kfree(wl->name);
+		kfree(wl);
+		return ERR_PTR(-ENOMEM);
+	}
+	wl->ws->last_time = ktime_get();
+
 	rb_link_node(&wl->node, parent, node);
 	rb_insert_color(&wl->node, &wakelocks_tree);
 	wakelocks_lru_add(wl);
@@ -233,9 +239,9 @@ int pm_wake_lock(const char *buf)
 		u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;
 
 		do_div(timeout_ms, NSEC_PER_MSEC);
-		__pm_wakeup_event(&wl->ws, timeout_ms);
+		__pm_wakeup_event(wl->ws, timeout_ms);
 	} else {
-		__pm_stay_awake(&wl->ws);
+		__pm_stay_awake(wl->ws);
 	}
 
 	wakelocks_lru_most_recent(wl);
@@ -271,7 +277,7 @@ int pm_wake_unlock(const char *buf)
 		ret = PTR_ERR(wl);
 		goto out;
 	}
-	__pm_relax(&wl->ws);
+	__pm_relax(wl->ws);
 
 	wakelocks_lru_most_recent(wl);
 	wakelocks_gc();
-- 
2.22.0.770.g0f2c4a37fd-goog

[PATCH v7 3/3] PM / wakeup: Show wakeup sources stats in sysfs

[Tri Vo]

Add an ID and a device pointer to 'struct wakeup_source'. Use them to to
expose wakeup sources statistics in sysfs under
/sys/class/wakeup/wakeup<ID>/*.

Co-developed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Tri Vo <trong@android.com>
Tested-by: Tri Vo <trong@android.com>
Tested-by: Kalesh Singh <kaleshsingh@google.com>
---
 Documentation/ABI/testing/sysfs-class-wakeup |  76 +++++++++
 drivers/acpi/device_pm.c                     |   3 +-
 drivers/base/power/Makefile                  |   2 +-
 drivers/base/power/power.h                   |   9 ++
 drivers/base/power/wakeup.c                  |  28 +++-
 drivers/base/power/wakeup_stats.c            | 161 +++++++++++++++++++
 fs/eventpoll.c                               |   4 +-
 include/linux/pm_wakeup.h                    |  10 +-
 kernel/power/autosleep.c                     |   2 +-
 kernel/power/wakelock.c                      |   2 +-
 kernel/time/alarmtimer.c                     |   2 +-
 11 files changed, 286 insertions(+), 13 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-wakeup
 create mode 100644 drivers/base/power/wakeup_stats.c

diff --git a/Documentation/ABI/testing/sysfs-class-wakeup b/Documentation/ABI/testing/sysfs-class-wakeup
new file mode 100644
index 000000000000..754aab8b6dcd
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-wakeup
@@ -0,0 +1,76 @@
+What:		/sys/class/wakeup/
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		The /sys/class/wakeup/ directory contains pointers to all
+		wakeup sources in the kernel at that moment in time.
+
+What:		/sys/class/wakeup/.../name
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the name of the wakeup source.
+
+What:		/sys/class/wakeup/.../active_count
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the number of times the wakeup source was
+		activated.
+
+What:		/sys/class/wakeup/.../event_count
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the number of signaled wakeup events
+		associated with the wakeup source.
+
+What:		/sys/class/wakeup/.../wakeup_count
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the number of times the wakeup source might
+		abort suspend.
+
+What:		/sys/class/wakeup/.../expire_count
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the number of times the wakeup source's
+		timeout has expired.
+
+What:		/sys/class/wakeup/.../active_time_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the amount of time the wakeup source has
+		been continuously active, in milliseconds.  If the wakeup
+		source is not active, this file contains '0'.
+
+What:		/sys/class/wakeup/.../total_time_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the total amount of time this wakeup source
+		has been active, in milliseconds.
+
+What:		/sys/class/wakeup/.../max_time_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the maximum amount of time this wakeup
+		source has been continuously active, in milliseconds.
+
+What:		/sys/class/wakeup/.../last_change_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the monotonic clock time when the wakeup
+		source was touched last time, in milliseconds.
+
+What:		/sys/class/wakeup/.../prevent_suspend_time_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		The file contains the total amount of time this wakeup source
+		has been preventing autosleep, in milliseconds.
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 28cffaaf9d82..91634e2dba8a 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -495,7 +495,8 @@ acpi_status acpi_add_pm_notifier(struct acpi_device *adev, struct device *dev,
 		goto out;
 
 	mutex_lock(&acpi_pm_notifier_lock);
-	adev->wakeup.ws = wakeup_source_register(dev_name(&adev->dev));
+	adev->wakeup.ws = wakeup_source_register(&adev->dev,
+						 dev_name(&adev->dev));
 	adev->wakeup.context.dev = dev;
 	adev->wakeup.context.func = func;
 	adev->wakeup.flags.notifier_present = true;
diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile
index e1bb691cf8f1..ec5bb190b9d0 100644
--- a/drivers/base/power/Makefile
+++ b/drivers/base/power/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_PM)	+= sysfs.o generic_ops.o common.o qos.o runtime.o wakeirq.o
-obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o
+obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o wakeup_stats.o
 obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o
 obj-$(CONFIG_PM_GENERIC_DOMAINS)	+=  domain.o domain_governor.o
 obj-$(CONFIG_HAVE_CLK)	+= clock_ops.o
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index ec33fbdb919b..57b1d1d88c8e 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -149,3 +149,12 @@ static inline void device_pm_init(struct device *dev)
 	device_pm_sleep_init(dev);
 	pm_runtime_init(dev);
 }
+
+#ifdef CONFIG_PM_SLEEP
+
+/* drivers/base/power/wakeup_stats.c */
+extern int wakeup_source_sysfs_add(struct device *parent,
+				   struct wakeup_source *ws);
+extern void wakeup_source_sysfs_remove(struct wakeup_source *ws);
+
+#endif /* CONFIG_PM_SLEEP */
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 3938892c8903..973675f24314 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -72,6 +72,8 @@ static struct wakeup_source deleted_ws = {
 	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
 };
 
+static DEFINE_IDA(wakeup_ida);
+
 /**
  * wakeup_source_create - Create a struct wakeup_source object.
  * @name: Name of the new wakeup source.
@@ -80,6 +82,7 @@ struct wakeup_source *wakeup_source_create(const char *name)
 {
 	struct wakeup_source *ws;
 	const char *ws_name;
+	int id;
 
 	ws = kzalloc(sizeof(*ws), GFP_KERNEL);
 	if (!ws)
@@ -90,8 +93,15 @@ struct wakeup_source *wakeup_source_create(const char *name)
 		goto err_name;
 	ws->name = ws_name;
 
+	id = ida_alloc(&wakeup_ida, GFP_KERNEL);
+	if (id < 0)
+		goto err_id;
+	ws->id = id;
+
 	return ws;
 
+err_id:
+	kfree_const(ws->name);
 err_name:
 	kfree(ws);
 err_ws:
@@ -140,6 +150,7 @@ void wakeup_source_destroy(struct wakeup_source *ws)
 
 	__pm_relax(ws);
 	wakeup_source_record(ws);
+	ida_free(&wakeup_ida, ws->id);
 	kfree_const(ws->name);
 	kfree(ws);
 }
@@ -193,16 +204,24 @@ EXPORT_SYMBOL_GPL(wakeup_source_remove);
 
 /**
  * wakeup_source_register - Create wakeup source and add it to the list.
+ * @dev: Device this wakeup source is associated with (or NULL if virtual).
  * @name: Name of the wakeup source to register.
  */
-struct wakeup_source *wakeup_source_register(const char *name)
+struct wakeup_source *wakeup_source_register(struct device *dev,
+					     const char *name)
 {
 	struct wakeup_source *ws;
+	int ret;
 
 	ws = wakeup_source_create(name);
-	if (ws)
+	if (ws) {
+		ret = wakeup_source_sysfs_add(dev, ws);
+		if (ret) {
+			wakeup_source_destroy(ws);
+			return NULL;
+		}
 		wakeup_source_add(ws);
-
+	}
 	return ws;
 }
 EXPORT_SYMBOL_GPL(wakeup_source_register);
@@ -215,6 +234,7 @@ void wakeup_source_unregister(struct wakeup_source *ws)
 {
 	if (ws) {
 		wakeup_source_remove(ws);
+		wakeup_source_sysfs_remove(ws);
 		wakeup_source_destroy(ws);
 	}
 }
@@ -258,7 +278,7 @@ int device_wakeup_enable(struct device *dev)
 	if (pm_suspend_target_state != PM_SUSPEND_ON)
 		dev_dbg(dev, "Suspicious %s() during system transition!\n", __func__);
 
-	ws = wakeup_source_register(dev_name(dev));
+	ws = wakeup_source_register(dev, dev_name(dev));
 	if (!ws)
 		return -ENOMEM;
 
diff --git a/drivers/base/power/wakeup_stats.c b/drivers/base/power/wakeup_stats.c
new file mode 100644
index 000000000000..3a4f55028e27
--- /dev/null
+++ b/drivers/base/power/wakeup_stats.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Wakeup statistics in sysfs
+ *
+ * Copyright (c) 2019 Linux Foundation
+ * Copyright (c) 2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (c) 2019 Google Inc.
+ */
+
+#include <linux/idr.h>
+#include <linux/kdev_t.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+#include "power.h"
+
+static struct class *wakeup_class;
+
+#define wakeup_attr(_name)						\
+static ssize_t _name##_show(struct device *dev,				\
+			    struct device_attribute *attr, char *buf)	\
+{									\
+	struct wakeup_source *ws = dev_get_drvdata(dev);		\
+									\
+	return sprintf(buf, "%lu\n", ws->_name);			\
+}									\
+static DEVICE_ATTR_RO(_name)
+
+wakeup_attr(active_count);
+wakeup_attr(event_count);
+wakeup_attr(wakeup_count);
+wakeup_attr(expire_count);
+
+static ssize_t active_time_ms_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+	ktime_t active_time =
+		ws->active ? ktime_sub(ktime_get(), ws->last_time) : 0;
+
+	return sprintf(buf, "%lld\n", ktime_to_ms(active_time));
+}
+static DEVICE_ATTR_RO(active_time_ms);
+
+static ssize_t total_time_ms_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+	ktime_t active_time;
+	ktime_t total_time = ws->total_time;
+
+	if (ws->active) {
+		active_time = ktime_sub(ktime_get(), ws->last_time);
+		total_time = ktime_add(total_time, active_time);
+	}
+	return sprintf(buf, "%lld\n", ktime_to_ms(total_time));
+}
+static DEVICE_ATTR_RO(total_time_ms);
+
+static ssize_t max_time_ms_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+	ktime_t active_time;
+	ktime_t max_time = ws->max_time;
+
+	if (ws->active) {
+		active_time = ktime_sub(ktime_get(), ws->last_time);
+		if (active_time > max_time)
+			max_time = active_time;
+	}
+	return sprintf(buf, "%lld\n", ktime_to_ms(max_time));
+}
+static DEVICE_ATTR_RO(max_time_ms);
+
+static ssize_t last_change_ms_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%lld\n", ktime_to_ms(ws->last_time));
+}
+static DEVICE_ATTR_RO(last_change_ms);
+
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", ws->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t prevent_suspend_time_ms_show(struct device *dev,
+					    struct device_attribute *attr,
+					    char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+	ktime_t prevent_sleep_time = ws->prevent_sleep_time;
+
+	if (ws->active && ws->autosleep_enabled) {
+		prevent_sleep_time = ktime_add(prevent_sleep_time,
+			ktime_sub(ktime_get(), ws->start_prevent_time));
+	}
+	return sprintf(buf, "%lld\n", ktime_to_ms(prevent_sleep_time));
+}
+static DEVICE_ATTR_RO(prevent_suspend_time_ms);
+
+static struct attribute *wakeup_source_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_active_count.attr,
+	&dev_attr_event_count.attr,
+	&dev_attr_wakeup_count.attr,
+	&dev_attr_expire_count.attr,
+	&dev_attr_active_time_ms.attr,
+	&dev_attr_total_time_ms.attr,
+	&dev_attr_max_time_ms.attr,
+	&dev_attr_last_change_ms.attr,
+	&dev_attr_prevent_suspend_time_ms.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(wakeup_source);
+
+/**
+ * wakeup_source_sysfs_add - Add wakeup_source attributes to sysfs.
+ * @parent: Device given wakeup source is associated with (or NULL if virtual).
+ * @ws: Wakeup source to be added in sysfs.
+ */
+int wakeup_source_sysfs_add(struct device *parent, struct wakeup_source *ws)
+{
+	struct device *dev;
+
+	dev = device_create_with_groups(wakeup_class, parent, MKDEV(0, 0), ws,
+					wakeup_source_groups, "wakeup%d",
+					ws->id);
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
+	ws->dev = dev;
+	pm_runtime_no_callbacks(ws->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wakeup_source_sysfs_add);
+
+/**
+ * wakeup_source_sysfs_remove - Remove wakeup_source attributes from sysfs.
+ * @ws: Wakeup source to be removed from sysfs.
+ */
+void wakeup_source_sysfs_remove(struct wakeup_source *ws)
+{
+	device_unregister(ws->dev);
+}
+EXPORT_SYMBOL_GPL(wakeup_source_sysfs_remove);
+
+static int __init wakeup_sources_sysfs_init(void)
+{
+	wakeup_class = class_create(THIS_MODULE, "wakeup");
+
+	return PTR_ERR_OR_ZERO(wakeup_class);
+}
+postcore_initcall(wakeup_sources_sysfs_init);
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index d7f1f5011fac..c4159bcc05d9 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1459,13 +1459,13 @@ static int ep_create_wakeup_source(struct epitem *epi)
 	struct wakeup_source *ws;
 
 	if (!epi->ep->ws) {
-		epi->ep->ws = wakeup_source_register("eventpoll");
+		epi->ep->ws = wakeup_source_register(NULL, "eventpoll");
 		if (!epi->ep->ws)
 			return -ENOMEM;
 	}
 
 	name = epi->ffd.file->f_path.dentry->d_name.name;
-	ws = wakeup_source_register(name);
+	ws = wakeup_source_register(NULL, name);
 
 	if (!ws)
 		return -ENOMEM;
diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index c0cad2d8f800..661efa029c96 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -21,6 +21,7 @@ struct wake_irq;
  * struct wakeup_source - Representation of wakeup sources
  *
  * @name: Name of the wakeup source
+ * @id: Wakeup source id
  * @entry: Wakeup source list entry
  * @lock: Wakeup source lock
  * @wakeirq: Optional device specific wakeirq
@@ -35,11 +36,13 @@ struct wake_irq;
  * @relax_count: Number of times the wakeup source was deactivated.
  * @expire_count: Number of times the wakeup source's timeout has expired.
  * @wakeup_count: Number of times the wakeup source might abort suspend.
+ * @dev: Struct device for sysfs statistics about the wakeup source.
  * @active: Status of the wakeup source.
  * @autosleep_enabled: Autosleep is active, so update @prevent_sleep_time.
  */
 struct wakeup_source {
 	const char 		*name;
+	int			id;
 	struct list_head	entry;
 	spinlock_t		lock;
 	struct wake_irq		*wakeirq;
@@ -55,6 +58,7 @@ struct wakeup_source {
 	unsigned long		relax_count;
 	unsigned long		expire_count;
 	unsigned long		wakeup_count;
+	struct device		*dev;
 	bool			active:1;
 	bool			autosleep_enabled:1;
 };
@@ -85,7 +89,8 @@ extern struct wakeup_source *wakeup_source_create(const char *name);
 extern void wakeup_source_destroy(struct wakeup_source *ws);
 extern void wakeup_source_add(struct wakeup_source *ws);
 extern void wakeup_source_remove(struct wakeup_source *ws);
-extern struct wakeup_source *wakeup_source_register(const char *name);
+extern struct wakeup_source *wakeup_source_register(struct device *dev,
+						    const char *name);
 extern void wakeup_source_unregister(struct wakeup_source *ws);
 extern int device_wakeup_enable(struct device *dev);
 extern int device_wakeup_disable(struct device *dev);
@@ -122,7 +127,8 @@ static inline void wakeup_source_add(struct wakeup_source *ws) {}
 
 static inline void wakeup_source_remove(struct wakeup_source *ws) {}
 
-static inline struct wakeup_source *wakeup_source_register(const char *name)
+static inline struct wakeup_source *wakeup_source_register(struct device *dev,
+							   const char *name)
 {
 	return NULL;
 }
diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
index 41e83a779e19..9af5a50d3489 100644
--- a/kernel/power/autosleep.c
+++ b/kernel/power/autosleep.c
@@ -116,7 +116,7 @@ int pm_autosleep_set_state(suspend_state_t state)
 
 int __init pm_autosleep_init(void)
 {
-	autosleep_ws = wakeup_source_register("autosleep");
+	autosleep_ws = wakeup_source_register(NULL, "autosleep");
 	if (!autosleep_ws)
 		return -ENOMEM;
 
diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
index d1eb7fd98b64..105df4dfc783 100644
--- a/kernel/power/wakelock.c
+++ b/kernel/power/wakelock.c
@@ -188,7 +188,7 @@ static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
 		return ERR_PTR(-ENOMEM);
 	}
 
-	wl->ws = wakeup_source_register(wl->name);
+	wl->ws = wakeup_source_register(NULL, wl->name);
 	if (!wl->ws) {
 		kfree(wl->name);
 		kfree(wl);
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 57518efc3810..93b382d9701c 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -97,7 +97,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
 	if (!device_may_wakeup(rtc->dev.parent))
 		return -1;
 
-	__ws = wakeup_source_register("alarmtimer");
+	__ws = wakeup_source_register(dev, "alarmtimer");
 
 	spin_lock_irqsave(&rtcdev_lock, flags);
 	if (!rtcdev) {
-- 
2.22.0.770.g0f2c4a37fd-goog

Re: [PATCH v7 1/3] PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()

[Stephen Boyd]

Quoting Tri Vo (2019-08-05 10:58:46)
> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> index ee31d4f8d856..3938892c8903 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -72,23 +72,6 @@ static struct wakeup_source deleted_ws = {
>         .lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
>  };
>  
> -/**
> - * wakeup_source_prepare - Prepare a new wakeup source for initialization.
> - * @ws: Wakeup source to prepare.
> - * @name: Pointer to the name of the new wakeup source.
> - *
> - * Callers must ensure that the @name string won't be freed when @ws is still in
> - * use.
> - */
> -void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
> -{
> -       if (ws) {
> -               memset(ws, 0, sizeof(*ws));
> -               ws->name = name;
> -       }
> -}
> -EXPORT_SYMBOL_GPL(wakeup_source_prepare);
> -
>  /**
>   * wakeup_source_create - Create a struct wakeup_source object.
>   * @name: Name of the new wakeup source.
> @@ -96,13 +79,23 @@ EXPORT_SYMBOL_GPL(wakeup_source_prepare);
>  struct wakeup_source *wakeup_source_create(const char *name)
>  {
>         struct wakeup_source *ws;
> +       const char *ws_name;
>  
> -       ws = kmalloc(sizeof(*ws), GFP_KERNEL);
> +       ws = kzalloc(sizeof(*ws), GFP_KERNEL);
>         if (!ws)
> -               return NULL;
> +               goto err_ws;
> +
> +       ws_name = kstrdup_const(name, GFP_KERNEL);
> +       if (!ws_name)

Does this intentionally change this function to return an error if
'name' is NULL? Before, wakeup_source_prepare() would just assign
ws->name to NULL, but now it errors out. I don't see how it's good or
useful to allow NULL for the wakeup source name, but it is what it is.

> +               goto err_name;
> +       ws->name = ws_name;
>  
> -       wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
>         return ws;
> +
> +err_name:
> +       kfree(ws);
> +err_ws:
> +       return NULL;
>  }
>  EXPORT_SYMBOL_GPL(wakeup_source_create);
>  

Re: [PATCH v7 2/3] PM / wakeup: Use wakeup_source_register() in wakelock.c

[Stephen Boyd]

Quoting Tri Vo (2019-08-05 10:58:47)
> kernel/power/wakelock.c duplicates wakeup source creation and
> registration code from drivers/base/power/wakeup.c.
> 
> Change struct wakelock's wakeup source to a pointer and use
> wakeup_source_register() function to create and register said wakeup
> source. Use wakeup_source_unregister() on cleanup path.
> 
> Signed-off-by: Tri Vo <trong@android.com>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

Re: [PATCH v7 3/3] PM / wakeup: Show wakeup sources stats in sysfs

[Stephen Boyd]

Quoting Tri Vo (2019-08-05 10:58:48)
> diff --git a/drivers/base/power/wakeup_stats.c b/drivers/base/power/wakeup_stats.c
> new file mode 100644
> index 000000000000..3a4f55028e27
> --- /dev/null
> +++ b/drivers/base/power/wakeup_stats.c
> @@ -0,0 +1,161 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Wakeup statistics in sysfs
> + *
> + * Copyright (c) 2019 Linux Foundation
> + * Copyright (c) 2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> + * Copyright (c) 2019 Google Inc.
> + */
> +
> +#include <linux/idr.h>
> +#include <linux/kdev_t.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/slab.h>

Can you include init.h, device.h, timekeeping.h, and kernel. here? This
file calls functions exported in those headers.

> +
> +#include "power.h"
> +
> +static struct class *wakeup_class;
> +
> +#define wakeup_attr(_name)                                             \
> +static ssize_t _name##_show(struct device *dev,                                \
> +                           struct device_attribute *attr, char *buf)   \
> +{                                                                      \
> +       struct wakeup_source *ws = dev_get_drvdata(dev);                \
> +                                                                       \
> +       return sprintf(buf, "%lu\n", ws->_name);                        \
> +}                                                                      \
> +static DEVICE_ATTR_RO(_name)
> +
> +wakeup_attr(active_count);
> +wakeup_attr(event_count);
> +wakeup_attr(wakeup_count);

Re: [PATCH v7 1/3] PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()

[Tri Vo]

On Mon, Aug 5, 2019 at 1:54 PM Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Tri Vo (2019-08-05 10:58:46)
> > diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> > index ee31d4f8d856..3938892c8903 100644
> > --- a/drivers/base/power/wakeup.c
> > +++ b/drivers/base/power/wakeup.c
> > @@ -72,23 +72,6 @@ static struct wakeup_source deleted_ws = {
> >         .lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
> >  };
> >
> > -/**
> > - * wakeup_source_prepare - Prepare a new wakeup source for initialization.
> > - * @ws: Wakeup source to prepare.
> > - * @name: Pointer to the name of the new wakeup source.
> > - *
> > - * Callers must ensure that the @name string won't be freed when @ws is still in
> > - * use.
> > - */
> > -void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
> > -{
> > -       if (ws) {
> > -               memset(ws, 0, sizeof(*ws));
> > -               ws->name = name;
> > -       }
> > -}
> > -EXPORT_SYMBOL_GPL(wakeup_source_prepare);
> > -
> >  /**
> >   * wakeup_source_create - Create a struct wakeup_source object.
> >   * @name: Name of the new wakeup source.
> > @@ -96,13 +79,23 @@ EXPORT_SYMBOL_GPL(wakeup_source_prepare);
> >  struct wakeup_source *wakeup_source_create(const char *name)
> >  {
> >         struct wakeup_source *ws;
> > +       const char *ws_name;
> >
> > -       ws = kmalloc(sizeof(*ws), GFP_KERNEL);
> > +       ws = kzalloc(sizeof(*ws), GFP_KERNEL);
> >         if (!ws)
> > -               return NULL;
> > +               goto err_ws;
> > +
> > +       ws_name = kstrdup_const(name, GFP_KERNEL);
> > +       if (!ws_name)
>
> Does this intentionally change this function to return an error if
> 'name' is NULL? Before, wakeup_source_prepare() would just assign
> ws->name to NULL, but now it errors out. I don't see how it's good or
> useful to allow NULL for the wakeup source name, but it is what it is.

Yes, the change to not allow ws->name to be NULL is intentional.

Re: [PATCH v7 1/3] PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()

[Stephen Boyd]

Quoting Tri Vo (2019-08-05 14:11:55)
> On Mon, Aug 5, 2019 at 1:54 PM Stephen Boyd <swboyd@chromium.org> wrote:
> >
> > Quoting Tri Vo (2019-08-05 10:58:46)
> > > @@ -96,13 +79,23 @@ EXPORT_SYMBOL_GPL(wakeup_source_prepare);
> > >  struct wakeup_source *wakeup_source_create(const char *name)
> > >  {
> > >         struct wakeup_source *ws;
> > > +       const char *ws_name;
> > >
> > > -       ws = kmalloc(sizeof(*ws), GFP_KERNEL);
> > > +       ws = kzalloc(sizeof(*ws), GFP_KERNEL);
> > >         if (!ws)
> > > -               return NULL;
> > > +               goto err_ws;
> > > +
> > > +       ws_name = kstrdup_const(name, GFP_KERNEL);
> > > +       if (!ws_name)
> >
> > Does this intentionally change this function to return an error if
> > 'name' is NULL? Before, wakeup_source_prepare() would just assign
> > ws->name to NULL, but now it errors out. I don't see how it's good or
> > useful to allow NULL for the wakeup source name, but it is what it is.
> 
> Yes, the change to not allow ws->name to be NULL is intentional.

Ok. It would be good to mention it in the commit text so we don't think
it was a bug when looking back a few months later.

Re: [PATCH v7 3/3] PM / wakeup: Show wakeup sources stats in sysfs

[Stephen Boyd]

Quoting Tri Vo (2019-08-05 10:58:48)
> diff --git a/drivers/base/power/wakeup_stats.c b/drivers/base/power/wakeup_stats.c
> new file mode 100644
> index 000000000000..3a4f55028e27
> --- /dev/null
> +++ b/drivers/base/power/wakeup_stats.c
> @@ -0,0 +1,161 @@
[...]
> +/**
> + * wakeup_source_sysfs_add - Add wakeup_source attributes to sysfs.
> + * @parent: Device given wakeup source is associated with (or NULL if virtual).
> + * @ws: Wakeup source to be added in sysfs.
> + */
> +int wakeup_source_sysfs_add(struct device *parent, struct wakeup_source *ws)
> +{
> +       struct device *dev;
> +
> +       dev = device_create_with_groups(wakeup_class, parent, MKDEV(0, 0), ws,
> +                                       wakeup_source_groups, "wakeup%d",
> +                                       ws->id);
> +       if (IS_ERR(dev))
> +               return PTR_ERR(dev);
> +       ws->dev = dev;
> +       pm_runtime_no_callbacks(ws->dev);

Does this only avoid adding runtime PM attributes?

I thought we would call device_set_pm_not_required() on the device here.
Probably requiring a bit of copy/paste from device_create_with_groups()
so that it can be set before the device is registered. Or another
version of device_create_with_groups() that does everything besides call
device_add().

> +
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(wakeup_source_sysfs_add);
> +

Re: [PATCH v7 3/3] PM / wakeup: Show wakeup sources stats in sysfs

[Tri Vo]

On Mon, Aug 5, 2019 at 4:29 PM Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Tri Vo (2019-08-05 10:58:48)
> > diff --git a/drivers/base/power/wakeup_stats.c b/drivers/base/power/wakeup_stats.c
> > new file mode 100644
> > index 000000000000..3a4f55028e27
> > --- /dev/null
> > +++ b/drivers/base/power/wakeup_stats.c
> > @@ -0,0 +1,161 @@
> [...]
> > +/**
> > + * wakeup_source_sysfs_add - Add wakeup_source attributes to sysfs.
> > + * @parent: Device given wakeup source is associated with (or NULL if virtual).
> > + * @ws: Wakeup source to be added in sysfs.
> > + */
> > +int wakeup_source_sysfs_add(struct device *parent, struct wakeup_source *ws)
> > +{
> > +       struct device *dev;
> > +
> > +       dev = device_create_with_groups(wakeup_class, parent, MKDEV(0, 0), ws,
> > +                                       wakeup_source_groups, "wakeup%d",
> > +                                       ws->id);
> > +       if (IS_ERR(dev))
> > +               return PTR_ERR(dev);
> > +       ws->dev = dev;
> > +       pm_runtime_no_callbacks(ws->dev);
>
> Does this only avoid adding runtime PM attributes?
>
> I thought we would call device_set_pm_not_required() on the device here.
> Probably requiring a bit of copy/paste from device_create_with_groups()
> so that it can be set before the device is registered. Or another
> version of device_create_with_groups() that does everything besides call
> device_add().

Comments on pm_runtime_no_callbacks() say,
  "Set the power.no_callbacks flag, which tells the PM core that this
   device is power-managed through its parent and has no runtime PM
   callbacks of its own.  The runtime sysfs attributes will be removed."

Sound like it's appropriate to apply this function to the wakeup source.

Re: [PATCH v7 3/3] PM / wakeup: Show wakeup sources stats in sysfs

[Rafael J. Wysocki]

On Tue, Aug 6, 2019 at 8:51 PM Tri Vo <trong@android.com> wrote:
>
> On Mon, Aug 5, 2019 at 4:29 PM Stephen Boyd <swboyd@chromium.org> wrote:
> >
> > Quoting Tri Vo (2019-08-05 10:58:48)
> > > diff --git a/drivers/base/power/wakeup_stats.c b/drivers/base/power/wakeup_stats.c
> > > new file mode 100644
> > > index 000000000000..3a4f55028e27
> > > --- /dev/null
> > > +++ b/drivers/base/power/wakeup_stats.c
> > > @@ -0,0 +1,161 @@
> > [...]
> > > +/**
> > > + * wakeup_source_sysfs_add - Add wakeup_source attributes to sysfs.
> > > + * @parent: Device given wakeup source is associated with (or NULL if virtual).
> > > + * @ws: Wakeup source to be added in sysfs.
> > > + */
> > > +int wakeup_source_sysfs_add(struct device *parent, struct wakeup_source *ws)
> > > +{
> > > +       struct device *dev;
> > > +
> > > +       dev = device_create_with_groups(wakeup_class, parent, MKDEV(0, 0), ws,
> > > +                                       wakeup_source_groups, "wakeup%d",
> > > +                                       ws->id);
> > > +       if (IS_ERR(dev))
> > > +               return PTR_ERR(dev);
> > > +       ws->dev = dev;
> > > +       pm_runtime_no_callbacks(ws->dev);
> >
> > Does this only avoid adding runtime PM attributes?
> >
> > I thought we would call device_set_pm_not_required() on the device here.
> > Probably requiring a bit of copy/paste from device_create_with_groups()
> > so that it can be set before the device is registered. Or another
> > version of device_create_with_groups() that does everything besides call
> > device_add().
>
> Comments on pm_runtime_no_callbacks() say,
>   "Set the power.no_callbacks flag, which tells the PM core that this
>    device is power-managed through its parent and has no runtime PM
>    callbacks of its own.  The runtime sysfs attributes will be removed."
>
> Sound like it's appropriate to apply this function to the wakeup source.

This is only useful if you ever enable PM-runtime for this device.
Which you won't do.

You could use device_set_pm_not_required(), though.