sysfs.c

Go to the documentation of this file.

/*
 * drivers/base/power/sysfs.c - sysfs entries for device PM
 */

#include <linux/device.h>
#include <linux/string.h>
#include <linux/export.h>
#include <linux/pm_qos.h>
#include <linux/pm_runtime.h>
#include <linux/atomic.h>
#include <linux/jiffies.h>
#include "power.h"

/*
 *  control - Report/change current runtime PM setting of the device
 *
 *  Runtime power management of a device can be blocked with the help of
 *  this attribute.  All devices have one of the following two values for
 *  the power/control file:
 *
 *   + "auto\n" to allow the device to be power managed at run time;
 *   + "on\n" to prevent the device from being power managed at run time;
 *
 *  The default for all devices is "auto", which means that devices may be
 *  subject to automatic power management, depending on their drivers.
 *  Changing this attribute to "on" prevents the driver from power managing
 *  the device at run time.  Doing that while the device is suspended causes
 *  it to be woken up.
 *
 *  wakeup - Report/change current wakeup option for device
 *
 *  Some devices support "wakeup" events, which are hardware signals
 *  used to activate devices from suspended or low power states.  Such
 *  devices have one of three values for the sysfs power/wakeup file:
 *
 *   + "enabled\n" to issue the events;
 *   + "disabled\n" not to do so; or
 *   + "\n" for temporary or permanent inability to issue wakeup.
 *
 *  (For example, unconfigured USB devices can't issue wakeups.)
 *
 *  Familiar examples of devices that can issue wakeup events include
 *  keyboards and mice (both PS2 and USB styles), power buttons, modems,
 *  "Wake-On-LAN" Ethernet links, GPIO lines, and more.  Some events
 *  will wake the entire system from a suspend state; others may just
 *  wake up the device (if the system as a whole is already active).
 *  Some wakeup events use normal IRQ lines; other use special out
 *  of band signaling.
 *
 *  It is the responsibility of device drivers to enable (or disable)
 *  wakeup signaling as part of changing device power states, respecting
 *  the policy choices provided through the driver model.
 *
 *  Devices may not be able to generate wakeup events from all power
 *  states.  Also, the events may be ignored in some configurations;
 *  for example, they might need help from other devices that aren't
 *  active, or which may have wakeup disabled.  Some drivers rely on
 *  wakeup events internally (unless they are disabled), keeping
 *  their hardware in low power modes whenever they're unused.  This
 *  saves runtime power, without requiring system-wide sleep states.
 *
 *  async - Report/change current async suspend setting for the device
 *
 *  Asynchronous suspend and resume of the device during system-wide power
 *  state transitions can be enabled by writing "enabled" to this file.
 *  Analogously, if "disabled" is written to this file, the device will be
 *  suspended and resumed synchronously.
 *
 *  All devices have one of the following two values for power/async:
 *
 *   + "enabled\n" to permit the asynchronous suspend/resume of the device;
 *   + "disabled\n" to forbid it;
 *
 *  NOTE: It generally is unsafe to permit the asynchronous suspend/resume
 *  of a device unless it is certain that all of the PM dependencies of the
 *  device are known to the PM core.  However, for some devices this
 *  attribute is set to "enabled" by bus type code or device drivers and in
 *  that cases it should be safe to leave the default value.
 *
 *  autosuspend_delay_ms - Report/change a device's autosuspend_delay value
 *
 *  Some drivers don't want to carry out a runtime suspend as soon as a
 *  device becomes idle; they want it always to remain idle for some period
 *  of time before suspending it.  This period is the autosuspend_delay
 *  value (expressed in milliseconds) and it can be controlled by the user.
 *  If the value is negative then the device will never be runtime
 *  suspended.
 *
 *  NOTE: The autosuspend_delay_ms attribute and the autosuspend_delay
 *  value are used only if the driver calls pm_runtime_use_autosuspend().
 *
 *  wakeup_count - Report the number of wakeup events related to the device
 */

static const char enabled[] = "enabled";
static const char disabled[] = "disabled";

const char power_group_name[] = "power";
EXPORT_SYMBOL_GPL(power_group_name);

#ifdef CONFIG_PM_RUNTIME
static const char ctrl_auto[] = "auto";
static const char ctrl_on[] = "on";

static ssize_t control_show(struct device *dev, struct device_attribute *attr,
                char *buf)
{
    return sprintf(buf, "%s\n",
                dev->power.runtime_auto ? ctrl_auto : ctrl_on);
}

static ssize_t control_store(struct device * dev, struct device_attribute *attr,
                 const char * buf, size_t n)
{
    char *cp;
    int len = n;

    cp = memchr(buf, '\n', n);
    if (cp)
        len = cp - buf;
    device_lock(dev);
    if (len == sizeof ctrl_auto - 1 && strncmp(buf, ctrl_auto, len) == 0)
        pm_runtime_allow(dev);
    else if (len == sizeof ctrl_on - 1 && strncmp(buf, ctrl_on, len) == 0)
        pm_runtime_forbid(dev);
    else
        n = -EINVAL;
    device_unlock(dev);
    return n;
}

static DEVICE_ATTR(control, 0644, control_show, control_store);

static ssize_t rtpm_active_time_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    int ret;
    spin_lock_irq(&dev->power.lock);
    update_pm_runtime_accounting(dev);
    ret = sprintf(buf, "%i\n", jiffies_to_msecs(dev->power.active_jiffies));
    spin_unlock_irq(&dev->power.lock);
    return ret;
}

static DEVICE_ATTR(runtime_active_time, 0444, rtpm_active_time_show, NULL);

static ssize_t rtpm_suspended_time_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    int ret;
    spin_lock_irq(&dev->power.lock);
    update_pm_runtime_accounting(dev);
    ret = sprintf(buf, "%i\n",
        jiffies_to_msecs(dev->power.suspended_jiffies));
    spin_unlock_irq(&dev->power.lock);
    return ret;
}

static DEVICE_ATTR(runtime_suspended_time, 0444, rtpm_suspended_time_show, NULL);

static ssize_t rtpm_status_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    const char *p;

    if (dev->power.runtime_error) {
        p = "error\n";
    } else if (dev->power.disable_depth) {
        p = "unsupported\n";
    } else {
        switch (dev->power.runtime_status) {
        case RPM_SUSPENDED:
            p = "suspended\n";
            break;
        case RPM_SUSPENDING:
            p = "suspending\n";
            break;
        case RPM_RESUMING:
            p = "resuming\n";
            break;
        case RPM_ACTIVE:
            p = "active\n";
            break;
        default:
            return -EIO;
        }
    }
    return sprintf(buf, p);
}

static DEVICE_ATTR(runtime_status, 0444, rtpm_status_show, NULL);

static ssize_t autosuspend_delay_ms_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
    if (!dev->power.use_autosuspend)
        return -EIO;
    return sprintf(buf, "%d\n", dev->power.autosuspend_delay);
}

static ssize_t autosuspend_delay_ms_store(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t n)
{
    long delay;

    if (!dev->power.use_autosuspend)
        return -EIO;

    if (strict_strtol(buf, 10, &delay) != 0 || delay != (int) delay)
        return -EINVAL;

    device_lock(dev);
    pm_runtime_set_autosuspend_delay(dev, delay);
    device_unlock(dev);
    return n;
}

static DEVICE_ATTR(autosuspend_delay_ms, 0644, autosuspend_delay_ms_show,
        autosuspend_delay_ms_store);

static ssize_t pm_qos_latency_show(struct device *dev,
                   struct device_attribute *attr, char *buf)
{
    return sprintf(buf, "%d\n", dev->power.pq_req->node.prio);
}

static ssize_t pm_qos_latency_store(struct device *dev,
                    struct device_attribute *attr,
                    const char *buf, size_t n)
{
    s32 value;
    int ret;

    if (kstrtos32(buf, 0, &value))
        return -EINVAL;

    if (value < 0)
        return -EINVAL;

    ret = dev_pm_qos_update_request(dev->power.pq_req, value);
    return ret < 0 ? ret : n;
}

static DEVICE_ATTR(pm_qos_resume_latency_us, 0644,
           pm_qos_latency_show, pm_qos_latency_store);
#endif /* CONFIG_PM_RUNTIME */

#ifdef CONFIG_PM_SLEEP
static ssize_t
wake_show(struct device * dev, struct device_attribute *attr, char * buf)
{
    return sprintf(buf, "%s\n", device_can_wakeup(dev)
        ? (device_may_wakeup(dev) ? enabled : disabled)
        : "");
}

static ssize_t
wake_store(struct device * dev, struct device_attribute *attr,
    const char * buf, size_t n)
{
    char *cp;
    int len = n;

    if (!device_can_wakeup(dev))
        return -EINVAL;

    cp = memchr(buf, '\n', n);
    if (cp)
        len = cp - buf;
    if (len == sizeof enabled - 1
            && strncmp(buf, enabled, sizeof enabled - 1) == 0)
        device_set_wakeup_enable(dev, 1);
    else if (len == sizeof disabled - 1
            && strncmp(buf, disabled, sizeof disabled - 1) == 0)
        device_set_wakeup_enable(dev, 0);
    else
        return -EINVAL;
    return n;
}

static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);

static ssize_t wakeup_count_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    unsigned long count = 0;
    bool enabled = false;

    spin_lock_irq(&dev->power.lock);
    if (dev->power.wakeup) {
        count = dev->power.wakeup->event_count;
        enabled = true;
    }
    spin_unlock_irq(&dev->power.lock);
    return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_count, 0444, wakeup_count_show, NULL);

static ssize_t wakeup_active_count_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    unsigned long count = 0;
    bool enabled = false;

    spin_lock_irq(&dev->power.lock);
    if (dev->power.wakeup) {
        count = dev->power.wakeup->active_count;
        enabled = true;
    }
    spin_unlock_irq(&dev->power.lock);
    return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_active_count, 0444, wakeup_active_count_show, NULL);

static ssize_t wakeup_abort_count_show(struct device *dev,
                    struct device_attribute *attr,
                    char *buf)
{
    unsigned long count = 0;
    bool enabled = false;

    spin_lock_irq(&dev->power.lock);
    if (dev->power.wakeup) {
        count = dev->power.wakeup->wakeup_count;
        enabled = true;
    }
    spin_unlock_irq(&dev->power.lock);
    return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_abort_count, 0444, wakeup_abort_count_show, NULL);

static ssize_t wakeup_expire_count_show(struct device *dev,
                    struct device_attribute *attr,
                    char *buf)
{
    unsigned long count = 0;
    bool enabled = false;

    spin_lock_irq(&dev->power.lock);
    if (dev->power.wakeup) {
        count = dev->power.wakeup->expire_count;
        enabled = true;
    }
    spin_unlock_irq(&dev->power.lock);
    return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_expire_count, 0444, wakeup_expire_count_show, NULL);

static ssize_t wakeup_active_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    unsigned int active = 0;
    bool enabled = false;

    spin_lock_irq(&dev->power.lock);
    if (dev->power.wakeup) {
        active = dev->power.wakeup->active;
        enabled = true;
    }
    spin_unlock_irq(&dev->power.lock);
    return enabled ? sprintf(buf, "%u\n", active) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_active, 0444, wakeup_active_show, NULL);

static ssize_t wakeup_total_time_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    s64 msec = 0;
    bool enabled = false;

    spin_lock_irq(&dev->power.lock);
    if (dev->power.wakeup) {
        msec = ktime_to_ms(dev->power.wakeup->total_time);
        enabled = true;
    }
    spin_unlock_irq(&dev->power.lock);
    return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_total_time_ms, 0444, wakeup_total_time_show, NULL);

static ssize_t wakeup_max_time_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    s64 msec = 0;
    bool enabled = false;

    spin_lock_irq(&dev->power.lock);
    if (dev->power.wakeup) {
        msec = ktime_to_ms(dev->power.wakeup->max_time);
        enabled = true;
    }
    spin_unlock_irq(&dev->power.lock);
    return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_max_time_ms, 0444, wakeup_max_time_show, NULL);

static ssize_t wakeup_last_time_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    s64 msec = 0;
    bool enabled = false;

    spin_lock_irq(&dev->power.lock);
    if (dev->power.wakeup) {
        msec = ktime_to_ms(dev->power.wakeup->last_time);
        enabled = true;
    }
    spin_unlock_irq(&dev->power.lock);
    return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_last_time_ms, 0444, wakeup_last_time_show, NULL);

#ifdef CONFIG_PM_AUTOSLEEP
static ssize_t wakeup_prevent_sleep_time_show(struct device *dev,
                          struct device_attribute *attr,
                          char *buf)
{
    s64 msec = 0;
    bool enabled = false;

    spin_lock_irq(&dev->power.lock);
    if (dev->power.wakeup) {
        msec = ktime_to_ms(dev->power.wakeup->prevent_sleep_time);
        enabled = true;
    }
    spin_unlock_irq(&dev->power.lock);
    return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
}

static DEVICE_ATTR(wakeup_prevent_sleep_time_ms, 0444,
           wakeup_prevent_sleep_time_show, NULL);
#endif /* CONFIG_PM_AUTOSLEEP */
#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_PM_ADVANCED_DEBUG
#ifdef CONFIG_PM_RUNTIME

static ssize_t rtpm_usagecount_show(struct device *dev,
                    struct device_attribute *attr, char *buf)
{
    return sprintf(buf, "%d\n", atomic_read(&dev->power.usage_count));
}

static ssize_t rtpm_children_show(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    return sprintf(buf, "%d\n", dev->power.ignore_children ?
        0 : atomic_read(&dev->power.child_count));
}

static ssize_t rtpm_enabled_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
{
    if ((dev->power.disable_depth) && (dev->power.runtime_auto == false))
        return sprintf(buf, "disabled & forbidden\n");
    else if (dev->power.disable_depth)
        return sprintf(buf, "disabled\n");
    else if (dev->power.runtime_auto == false)
        return sprintf(buf, "forbidden\n");
    return sprintf(buf, "enabled\n");
}

static DEVICE_ATTR(runtime_usage, 0444, rtpm_usagecount_show, NULL);
static DEVICE_ATTR(runtime_active_kids, 0444, rtpm_children_show, NULL);
static DEVICE_ATTR(runtime_enabled, 0444, rtpm_enabled_show, NULL);

#endif

#ifdef CONFIG_PM_SLEEP

static ssize_t async_show(struct device *dev, struct device_attribute *attr,
              char *buf)
{
    return sprintf(buf, "%s\n",
            device_async_suspend_enabled(dev) ? enabled : disabled);
}

static ssize_t async_store(struct device *dev, struct device_attribute *attr,
               const char *buf, size_t n)
{
    char *cp;
    int len = n;

    cp = memchr(buf, '\n', n);
    if (cp)
        len = cp - buf;
    if (len == sizeof enabled - 1 && strncmp(buf, enabled, len) == 0)
        device_enable_async_suspend(dev);
    else if (len == sizeof disabled - 1 && strncmp(buf, disabled, len) == 0)
        device_disable_async_suspend(dev);
    else
        return -EINVAL;
    return n;
}

static DEVICE_ATTR(async, 0644, async_show, async_store);

#endif
#endif /* CONFIG_PM_ADVANCED_DEBUG */

static struct attribute *power_attrs[] = {
#ifdef CONFIG_PM_ADVANCED_DEBUG
#ifdef CONFIG_PM_SLEEP
    &dev_attr_async.attr,
#endif
#ifdef CONFIG_PM_RUNTIME
    &dev_attr_runtime_status.attr,
    &dev_attr_runtime_usage.attr,
    &dev_attr_runtime_active_kids.attr,
    &dev_attr_runtime_enabled.attr,
#endif
#endif /* CONFIG_PM_ADVANCED_DEBUG */
    NULL,
};
static struct attribute_group pm_attr_group = {
    .name   = power_group_name,
    .attrs  = power_attrs,
};

static struct attribute *wakeup_attrs[] = {
#ifdef CONFIG_PM_SLEEP
    &dev_attr_wakeup.attr,
    &dev_attr_wakeup_count.attr,
    &dev_attr_wakeup_active_count.attr,
    &dev_attr_wakeup_abort_count.attr,
    &dev_attr_wakeup_expire_count.attr,
    &dev_attr_wakeup_active.attr,
    &dev_attr_wakeup_total_time_ms.attr,
    &dev_attr_wakeup_max_time_ms.attr,
    &dev_attr_wakeup_last_time_ms.attr,
#ifdef CONFIG_PM_AUTOSLEEP
    &dev_attr_wakeup_prevent_sleep_time_ms.attr,
#endif
#endif
    NULL,
};
static struct attribute_group pm_wakeup_attr_group = {
    .name   = power_group_name,
    .attrs  = wakeup_attrs,
};

static struct attribute *runtime_attrs[] = {
#ifdef CONFIG_PM_RUNTIME
#ifndef CONFIG_PM_ADVANCED_DEBUG
    &dev_attr_runtime_status.attr,
#endif
    &dev_attr_control.attr,
    &dev_attr_runtime_suspended_time.attr,
    &dev_attr_runtime_active_time.attr,
    &dev_attr_autosuspend_delay_ms.attr,
#endif /* CONFIG_PM_RUNTIME */
    NULL,
};
static struct attribute_group pm_runtime_attr_group = {
    .name   = power_group_name,
    .attrs  = runtime_attrs,
};

static struct attribute *pm_qos_attrs[] = {
#ifdef CONFIG_PM_RUNTIME
    &dev_attr_pm_qos_resume_latency_us.attr,
#endif /* CONFIG_PM_RUNTIME */
    NULL,
};
static struct attribute_group pm_qos_attr_group = {
    .name   = power_group_name,
    .attrs  = pm_qos_attrs,
};

int dpm_sysfs_add(struct device *dev)
{
    int rc;

    rc = sysfs_create_group(&dev->kobj, &pm_attr_group);
    if (rc)
        return rc;

    if (pm_runtime_callbacks_present(dev)) {
        rc = sysfs_merge_group(&dev->kobj, &pm_runtime_attr_group);
        if (rc)
            goto err_out;
    }

    if (device_can_wakeup(dev)) {
        rc = sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group);
        if (rc) {
            if (pm_runtime_callbacks_present(dev))
                sysfs_unmerge_group(&dev->kobj,
                            &pm_runtime_attr_group);
            goto err_out;
        }
    }
    return 0;

 err_out:
    sysfs_remove_group(&dev->kobj, &pm_attr_group);
    return rc;
}

int wakeup_sysfs_add(struct device *dev)
{
    return sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group);
}

void wakeup_sysfs_remove(struct device *dev)
{
    sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
}

int pm_qos_sysfs_add(struct device *dev)
{
    return sysfs_merge_group(&dev->kobj, &pm_qos_attr_group);
}

void pm_qos_sysfs_remove(struct device *dev)
{
    sysfs_unmerge_group(&dev->kobj, &pm_qos_attr_group);
}

void rpm_sysfs_remove(struct device *dev)
{
    sysfs_unmerge_group(&dev->kobj, &pm_runtime_attr_group);
}

void dpm_sysfs_remove(struct device *dev)
{
    rpm_sysfs_remove(dev);
    sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
    sysfs_remove_group(&dev->kobj, &pm_attr_group);
}