USB: Export suspend statistics

This patch exports two statistics to userspace:
/sys/bus/usb/device/.../power/connected_duration
/sys/bus/usb/device/.../power/active_duration

connected_duration is the total time (in msec) that the device has
been connected.  active_duration is the total time the device has not
been suspended.  With these two statistics, tools like PowerTOP can
calculate the percentage time that a device is active, i.e. not
suspended or auto-suspended.

Users can also use the active_duration to check if a device is actually
autosuspended.  Currently, they can set power/level to auto and
power/autosuspend to a positive timeout, but there's no way to know from
userspace if a device was actually autosuspended without looking at the
dmesg output.  These statistics will be useful in creating an automated
userspace script to test autosuspend for USB devices.

Signed-off-by: Sarah Sharp <sarah.a.sharp@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 60 insertions, 1 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index cc93aa9336fe..53fe049b40f5 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1034,8 +1034,10 @@ static void recursively_mark_NOTATTACHED(struct usb_device *udev)
                 if (udev->children[i])
                         recursively_mark_NOTATTACHED(udev->children[i]);
         }
-        if (udev->state == USB_STATE_SUSPENDED)
+        if (udev->state == USB_STATE_SUSPENDED) {
                 udev->discon_suspended = 1;
+                udev->active_duration -= jiffies;
+        }
         udev->state = USB_STATE_NOTATTACHED;
 }
 
@@ -1084,6 +1086,12 @@ void usb_set_device_state(struct usb_device *udev,
                         else
                                 device_init_wakeup(&udev->dev, 0);
                 }
+                if (udev->state == USB_STATE_SUSPENDED &&
+                        new_state != USB_STATE_SUSPENDED)
+                        udev->active_duration -= jiffies;
+                else if (new_state == USB_STATE_SUSPENDED &&
+                                udev->state != USB_STATE_SUSPENDED)
+                        udev->active_duration += jiffies;
                 udev->state = new_state;
         } else
                 recursively_mark_NOTATTACHED(udev);
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 32bd130b1eed..021b1d37462c 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -249,6 +249,41 @@ static void remove_persist_attributes(struct device *dev)
 #ifdef  CONFIG_USB_SUSPEND
 
 static ssize_t
+show_connected_duration(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct usb_device *udev = to_usb_device(dev);
+
+        return sprintf(buf, "%u\n",
+                        jiffies_to_msecs(jiffies - udev->connect_time));
+}
+
+static DEVICE_ATTR(connected_duration, S_IRUGO, show_connected_duration, NULL);
+
+/*
+ * If the device is resumed, the last time the device was suspended has
+ * been pre-subtracted from active_duration.  We add the current time to
+ * get the duration that the device was actually active.
+ *
+ * If the device is suspended, the active_duration is up-to-date.
+ */
+static ssize_t
+show_active_duration(struct device *dev, struct device_attribute *attr,
+                char *buf)
+{
+        struct usb_device *udev = to_usb_device(dev);
+        int duration;
+
+        if (udev->state != USB_STATE_SUSPENDED)
+                duration = jiffies_to_msecs(jiffies + udev->active_duration);
+        else
+                duration = jiffies_to_msecs(udev->active_duration);
+        return sprintf(buf, "%u\n", duration);
+}
+
+static DEVICE_ATTR(active_duration, S_IRUGO, show_active_duration, NULL);
+
+static ssize_t
 show_autosuspend(struct device *dev, struct device_attribute *attr, char *buf)
 {
         struct usb_device *udev = to_usb_device(dev);
@@ -365,6 +400,14 @@ static int add_power_attributes(struct device *dev)
                         rc = sysfs_add_file_to_group(&dev->kobj,
                                         &dev_attr_level.attr,
                                         power_group);
+                if (rc == 0)
+                        rc = sysfs_add_file_to_group(&dev->kobj,
+                                        &dev_attr_connected_duration.attr,
+                                        power_group);
+                if (rc == 0)
+                        rc = sysfs_add_file_to_group(&dev->kobj,
+                                        &dev_attr_active_duration.attr,
+                                        power_group);
         }
         return rc;
 }
@@ -372,6 +415,12 @@ static int add_power_attributes(struct device *dev)
 static void remove_power_attributes(struct device *dev)
 {
         sysfs_remove_file_from_group(&dev->kobj,
+                        &dev_attr_active_duration.attr,
+                        power_group);
+        sysfs_remove_file_from_group(&dev->kobj,
+                        &dev_attr_connected_duration.attr,
+                        power_group);
+        sysfs_remove_file_from_group(&dev->kobj,
                         &dev_attr_level.attr,
                         power_group);
         sysfs_remove_file_from_group(&dev->kobj,
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index bc5edacb0c34..fdb444d81271 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -339,6 +339,8 @@ usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
         mutex_init(&dev->pm_mutex);
         INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work);
         dev->autosuspend_delay = usb_autosuspend_delay * HZ;
+        dev->connect_time = jiffies;
+        dev->active_duration = -jiffies;
 #endif
         if (root_hub)   /* Root hub always ok [and always wired] */
                 dev->authorized = 1;