#include <linux/mutex.h>
#include <linux/pm.h>
#include <linux/resume-trace.h>
+#include <linux/rwsem.h>
#include "../base.h"
#include "power.h"
+/*
+ * The entries in the dpm_active list are in a depth first order, simply
+ * because children are guaranteed to be discovered after parents, and
+ * are inserted at the back of the list on discovery.
+ *
+ * All the other lists are kept in the same order, for consistency.
+ * However the lists aren't always traversed in the same order.
+ * Semaphores must be acquired from the top (i.e., front) down
+ * and released in the opposite order. Devices must be suspended
+ * from the bottom (i.e., end) up and resumed in the opposite order.
+ * That way no parent will be suspended while it still has an active
+ * child.
+ *
+ * Since device_pm_add() may be called with a device semaphore held,
+ * we must never try to acquire a device semaphore while holding
+ * dpm_list_mutex.
+ */
+
LIST_HEAD(dpm_active);
static LIST_HEAD(dpm_off);
static LIST_HEAD(dpm_off_irq);
-static DEFINE_MUTEX(dpm_mtx);
static DEFINE_MUTEX(dpm_list_mtx);
-int (*platform_enable_wakeup)(struct device *dev, int is_on);
-
+/* 'true' if all devices have been suspended, protected by dpm_list_mtx */
+static bool all_sleeping;
-void device_pm_add(struct device *dev)
+/**
+ * device_pm_add - add a device to the list of active devices
+ * @dev: Device to be added to the list
+ */
+int device_pm_add(struct device *dev)
{
+ int error = 0;
+
pr_debug("PM: Adding info for %s:%s\n",
dev->bus ? dev->bus->name : "No Bus",
kobject_name(&dev->kobj));
mutex_lock(&dpm_list_mtx);
- list_add_tail(&dev->power.entry, &dpm_active);
+ if ((dev->parent && dev->parent->power.sleeping) || all_sleeping) {
+ if (dev->parent->power.sleeping)
+ dev_warn(dev,
+ "parent %s is sleeping, will not add\n",
+ dev->parent->bus_id);
+ else
+ dev_warn(dev, "devices are sleeping, will not add\n");
+ WARN_ON(true);
+ error = -EBUSY;
+ } else {
+ error = dpm_sysfs_add(dev);
+ if (!error)
+ list_add_tail(&dev->power.entry, &dpm_active);
+ }
mutex_unlock(&dpm_list_mtx);
+ return error;
}
+/**
+ * device_pm_remove - remove a device from the list of active devices
+ * @dev: Device to be removed from the list
+ *
+ * This function also removes the device's PM-related sysfs attributes.
+ */
void device_pm_remove(struct device *dev)
{
pr_debug("PM: Removing info for %s:%s\n",
mutex_unlock(&dpm_list_mtx);
}
-
/*------------------------- Resume routines -------------------------*/
/**
- * resume_device - Restore state for one device.
+ * resume_device_early - Power on one device (early resume).
* @dev: Device.
*
+ * Must be called with interrupts disabled.
*/
+static int resume_device_early(struct device *dev)
+{
+ int error = 0;
+
+ TRACE_DEVICE(dev);
+ TRACE_RESUME(0);
-static int resume_device(struct device * dev)
+ if (dev->bus && dev->bus->resume_early) {
+ dev_dbg(dev, "EARLY resume\n");
+ error = dev->bus->resume_early(dev);
+ }
+
+ TRACE_RESUME(error);
+ return error;
+}
+
+/**
+ * dpm_power_up - Power on all regular (non-sysdev) devices.
+ *
+ * Walk the dpm_off_irq list and power each device up. This
+ * is used for devices that required they be powered down with
+ * interrupts disabled. As devices are powered on, they are moved
+ * to the dpm_off list.
+ *
+ * Must be called with interrupts disabled and only one CPU running.
+ */
+static void dpm_power_up(void)
+{
+
+ while (!list_empty(&dpm_off_irq)) {
+ struct list_head *entry = dpm_off_irq.next;
+ struct device *dev = to_device(entry);
+
+ list_move_tail(entry, &dpm_off);
+ resume_device_early(dev);
+ }
+}
+
+/**
+ * device_power_up - Turn on all devices that need special attention.
+ *
+ * Power on system devices, then devices that required we shut them down
+ * with interrupts disabled.
+ *
+ * Must be called with interrupts disabled.
+ */
+void device_power_up(void)
+{
+ sysdev_resume();
+ dpm_power_up();
+}
+EXPORT_SYMBOL_GPL(device_power_up);
+
+/**
+ * resume_device - Restore state for one device.
+ * @dev: Device.
+ *
+ */
+static int resume_device(struct device *dev)
{
int error = 0;
return error;
}
-
-static int resume_device_early(struct device * dev)
-{
- int error = 0;
-
- TRACE_DEVICE(dev);
- TRACE_RESUME(0);
- if (dev->bus && dev->bus->resume_early) {
- dev_dbg(dev,"EARLY resume\n");
- error = dev->bus->resume_early(dev);
- }
- TRACE_RESUME(error);
- return error;
-}
-
-/*
- * Resume the devices that have either not gone through
- * the late suspend, or that did go through it but also
- * went through the early resume
+/**
+ * dpm_resume - Resume every device.
+ *
+ * Resume the devices that have either not gone through
+ * the late suspend, or that did go through it but also
+ * went through the early resume.
+ *
+ * Take devices from the dpm_off_list, resume them,
+ * and put them on the dpm_locked list.
*/
static void dpm_resume(void)
{
mutex_lock(&dpm_list_mtx);
+ all_sleeping = false;
while(!list_empty(&dpm_off)) {
- struct list_head * entry = dpm_off.next;
- struct device * dev = to_device(entry);
+ struct list_head *entry = dpm_off.next;
+ struct device *dev = to_device(entry);
- get_device(dev);
list_move_tail(entry, &dpm_active);
-
+ dev->power.sleeping = false;
mutex_unlock(&dpm_list_mtx);
resume_device(dev);
mutex_lock(&dpm_list_mtx);
- put_device(dev);
}
mutex_unlock(&dpm_list_mtx);
}
-
/**
* device_resume - Restore state of each device in system.
*
- * Walk the dpm_off list, remove each entry, resume the device,
- * then add it to the dpm_active list.
+ * Resume all the devices, unlock them all, and allow new
+ * devices to be registered once again.
*/
-
void device_resume(void)
{
might_sleep();
- mutex_lock(&dpm_mtx);
dpm_resume();
- mutex_unlock(&dpm_mtx);
}
-
EXPORT_SYMBOL_GPL(device_resume);
-/**
- * dpm_power_up - Power on some devices.
- *
- * Walk the dpm_off_irq list and power each device up. This
- * is used for devices that required they be powered down with
- * interrupts disabled. As devices are powered on, they are moved
- * to the dpm_active list.
- *
- * Interrupts must be disabled when calling this.
- */
-
-static void dpm_power_up(void)
-{
- while(!list_empty(&dpm_off_irq)) {
- struct list_head * entry = dpm_off_irq.next;
- struct device * dev = to_device(entry);
-
- list_move_tail(entry, &dpm_off);
- resume_device_early(dev);
- }
-}
-
-
-/**
- * device_power_up - Turn on all devices that need special attention.
- *
- * Power on system devices then devices that required we shut them down
- * with interrupts disabled.
- * Called with interrupts disabled.
- */
-
-void device_power_up(void)
-{
- sysdev_resume();
- dpm_power_up();
-}
-
-EXPORT_SYMBOL_GPL(device_power_up);
-
-
/*------------------------- Suspend routines -------------------------*/
-/*
- * The entries in the dpm_active list are in a depth first order, simply
- * because children are guaranteed to be discovered after parents, and
- * are inserted at the back of the list on discovery.
- *
- * All list on the suspend path are done in reverse order, so we operate
- * on the leaves of the device tree (or forests, depending on how you want
- * to look at it ;) first. As nodes are removed from the back of the list,
- * they are inserted into the front of their destintation lists.
- *
- * Things are the reverse on the resume path - iterations are done in
- * forward order, and nodes are inserted at the back of their destination
- * lists. This way, the ancestors will be accessed before their descendents.
- */
-
static inline char *suspend_verb(u32 event)
{
switch (event) {
}
}
-
static void
suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
{
}
/**
- * suspend_device - Save state of one device.
+ * suspend_device_late - Shut down one device (late suspend).
* @dev: Device.
* @state: Power state device is entering.
+ *
+ * This is called with interrupts off and only a single CPU running.
*/
+static int suspend_device_late(struct device *dev, pm_message_t state)
+{
+ int error = 0;
-static int suspend_device(struct device * dev, pm_message_t state)
+ if (dev->bus && dev->bus->suspend_late) {
+ suspend_device_dbg(dev, state, "LATE ");
+ error = dev->bus->suspend_late(dev, state);
+ suspend_report_result(dev->bus->suspend_late, error);
+ }
+ return error;
+}
+
+/**
+ * device_power_down - Shut down special devices.
+ * @state: Power state to enter.
+ *
+ * Power down devices that require interrupts to be disabled
+ * and move them from the dpm_off list to the dpm_off_irq list.
+ * Then power down system devices.
+ *
+ * Must be called with interrupts disabled and only one CPU running.
+ */
+int device_power_down(pm_message_t state)
{
int error = 0;
- down(&dev->sem);
- if (dev->power.power_state.event) {
- dev_dbg(dev, "PM: suspend %d-->%d\n",
- dev->power.power_state.event, state.event);
+ while (!list_empty(&dpm_off)) {
+ struct list_head *entry = dpm_off.prev;
+ struct device *dev = to_device(entry);
+
+ error = suspend_device_late(dev, state);
+ if (error) {
+ printk(KERN_ERR "Could not power down device %s: "
+ "error %d\n",
+ kobject_name(&dev->kobj), error);
+ break;
+ }
+ if (!list_empty(&dev->power.entry))
+ list_move(&dev->power.entry, &dpm_off_irq);
}
+ if (!error)
+ error = sysdev_suspend(state);
+ if (error)
+ dpm_power_up();
+ return error;
+}
+EXPORT_SYMBOL_GPL(device_power_down);
+
+/**
+ * suspend_device - Save state of one device.
+ * @dev: Device.
+ * @state: Power state device is entering.
+ */
+static int suspend_device(struct device *dev, pm_message_t state)
+{
+ int error = 0;
+
+ down(&dev->sem);
+
if (dev->class && dev->class->suspend) {
suspend_device_dbg(dev, state, "class ");
error = dev->class->suspend(dev, state);
error = dev->bus->suspend(dev, state);
suspend_report_result(dev->bus->suspend, error);
}
- up(&dev->sem);
- return error;
-}
-
-/*
- * This is called with interrupts off, only a single CPU
- * running. We can't acquire a mutex or semaphore (and we don't
- * need the protection)
- */
-static int suspend_device_late(struct device *dev, pm_message_t state)
-{
- int error = 0;
+ up(&dev->sem);
- if (dev->bus && dev->bus->suspend_late) {
- suspend_device_dbg(dev, state, "LATE ");
- error = dev->bus->suspend_late(dev, state);
- suspend_report_result(dev->bus->suspend_late, error);
- }
return error;
}
/**
- * device_suspend - Save state and stop all devices in system.
- * @state: Power state to put each device in.
+ * dpm_suspend - Suspend every device.
+ * @state: Power state to put each device in.
*
- * Walk the dpm_active list, call ->suspend() for each device, and move
- * it to the dpm_off list.
+ * Walk the dpm_locked list. Suspend each device and move it
+ * to the dpm_off list.
*
* (For historical reasons, if it returns -EAGAIN, that used to mean
* that the device would be called again with interrupts disabled.
* These days, we use the "suspend_late()" callback for that, so we
* print a warning and consider it an error).
- *
- * If we get a different error, try and back out.
- *
- * If we hit a failure with any of the devices, call device_resume()
- * above to bring the suspended devices back to life.
- *
*/
-
-int device_suspend(pm_message_t state)
+static int dpm_suspend(pm_message_t state)
{
int error = 0;
- might_sleep();
- mutex_lock(&dpm_mtx);
mutex_lock(&dpm_list_mtx);
- while (!list_empty(&dpm_active) && error == 0) {
- struct list_head * entry = dpm_active.prev;
- struct device * dev = to_device(entry);
+ while (!list_empty(&dpm_active)) {
+ struct list_head *entry = dpm_active.prev;
+ struct device *dev = to_device(entry);
- get_device(dev);
- mutex_unlock(&dpm_list_mtx);
+ WARN_ON(dev->parent && dev->parent->power.sleeping);
+ dev->power.sleeping = true;
+ mutex_unlock(&dpm_list_mtx);
error = suspend_device(dev, state);
-
mutex_lock(&dpm_list_mtx);
-
- /* Check if the device got removed */
- if (!list_empty(&dev->power.entry)) {
- /* Move it to the dpm_off list */
- if (!error)
- list_move(&dev->power.entry, &dpm_off);
- }
- if (error)
+ if (error) {
printk(KERN_ERR "Could not suspend device %s: "
- "error %d%s\n",
- kobject_name(&dev->kobj), error,
- error == -EAGAIN ? " (please convert to suspend_late)" : "");
- put_device(dev);
+ "error %d%s\n",
+ kobject_name(&dev->kobj),
+ error,
+ (error == -EAGAIN ?
+ " (please convert to suspend_late)" :
+ ""));
+ dev->power.sleeping = false;
+ break;
+ }
+ if (!list_empty(&dev->power.entry))
+ list_move(&dev->power.entry, &dpm_off);
}
+ if (!error)
+ all_sleeping = true;
mutex_unlock(&dpm_list_mtx);
- if (error)
- dpm_resume();
- mutex_unlock(&dpm_mtx);
return error;
}
-EXPORT_SYMBOL_GPL(device_suspend);
-
/**
- * device_power_down - Shut down special devices.
- * @state: Power state to enter.
+ * device_suspend - Save state and stop all devices in system.
+ * @state: new power management state
*
- * Walk the dpm_off_irq list, calling ->power_down() for each device that
- * couldn't power down the device with interrupts enabled. When we're
- * done, power down system devices.
+ * Prevent new devices from being registered, then lock all devices
+ * and suspend them.
*/
-
-int device_power_down(pm_message_t state)
+int device_suspend(pm_message_t state)
{
- int error = 0;
- struct device * dev;
-
- while (!list_empty(&dpm_off)) {
- struct list_head * entry = dpm_off.prev;
-
- dev = to_device(entry);
- error = suspend_device_late(dev, state);
- if (error)
- goto Error;
- list_move(&dev->power.entry, &dpm_off_irq);
- }
+ int error;
- error = sysdev_suspend(state);
- Done:
+ might_sleep();
+ error = dpm_suspend(state);
+ if (error)
+ device_resume();
return error;
- Error:
- printk(KERN_ERR "Could not power down device %s: "
- "error %d\n", kobject_name(&dev->kobj), error);
- dpm_power_up();
- goto Done;
}
-
-EXPORT_SYMBOL_GPL(device_power_down);
+EXPORT_SYMBOL_GPL(device_suspend);
void __suspend_report_result(const char *function, void *fn, int ret)
{
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