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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /kernel/power/pm.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'kernel/power/pm.c')
-rw-r--r--kernel/power/pm.c265
1 files changed, 265 insertions, 0 deletions
diff --git a/kernel/power/pm.c b/kernel/power/pm.c
new file mode 100644
index 000000000000..61deda04e39e
--- /dev/null
+++ b/kernel/power/pm.c
@@ -0,0 +1,265 @@
+/*
+ * pm.c - Power management interface
+ *
+ * Copyright (C) 2000 Andrew Henroid
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/pm.h>
+#include <linux/interrupt.h>
+
+int pm_active;
+
+/*
+ * Locking notes:
+ * pm_devs_lock can be a semaphore providing pm ops are not called
+ * from an interrupt handler (already a bad idea so no change here). Each
+ * change must be protected so that an unlink of an entry doesn't clash
+ * with a pm send - which is permitted to sleep in the current architecture
+ *
+ * Module unloads clashing with pm events now work out safely, the module
+ * unload path will block until the event has been sent. It may well block
+ * until a resume but that will be fine.
+ */
+
+static DECLARE_MUTEX(pm_devs_lock);
+static LIST_HEAD(pm_devs);
+
+/**
+ * pm_register - register a device with power management
+ * @type: device type
+ * @id: device ID
+ * @callback: callback function
+ *
+ * Add a device to the list of devices that wish to be notified about
+ * power management events. A &pm_dev structure is returned on success,
+ * on failure the return is %NULL.
+ *
+ * The callback function will be called in process context and
+ * it may sleep.
+ */
+
+struct pm_dev *pm_register(pm_dev_t type,
+ unsigned long id,
+ pm_callback callback)
+{
+ struct pm_dev *dev = kmalloc(sizeof(struct pm_dev), GFP_KERNEL);
+ if (dev) {
+ memset(dev, 0, sizeof(*dev));
+ dev->type = type;
+ dev->id = id;
+ dev->callback = callback;
+
+ down(&pm_devs_lock);
+ list_add(&dev->entry, &pm_devs);
+ up(&pm_devs_lock);
+ }
+ return dev;
+}
+
+/**
+ * pm_unregister - unregister a device with power management
+ * @dev: device to unregister
+ *
+ * Remove a device from the power management notification lists. The
+ * dev passed must be a handle previously returned by pm_register.
+ */
+
+void pm_unregister(struct pm_dev *dev)
+{
+ if (dev) {
+ down(&pm_devs_lock);
+ list_del(&dev->entry);
+ up(&pm_devs_lock);
+
+ kfree(dev);
+ }
+}
+
+static void __pm_unregister(struct pm_dev *dev)
+{
+ if (dev) {
+ list_del(&dev->entry);
+ kfree(dev);
+ }
+}
+
+/**
+ * pm_unregister_all - unregister all devices with matching callback
+ * @callback: callback function pointer
+ *
+ * Unregister every device that would call the callback passed. This
+ * is primarily meant as a helper function for loadable modules. It
+ * enables a module to give up all its managed devices without keeping
+ * its own private list.
+ */
+
+void pm_unregister_all(pm_callback callback)
+{
+ struct list_head *entry;
+
+ if (!callback)
+ return;
+
+ down(&pm_devs_lock);
+ entry = pm_devs.next;
+ while (entry != &pm_devs) {
+ struct pm_dev *dev = list_entry(entry, struct pm_dev, entry);
+ entry = entry->next;
+ if (dev->callback == callback)
+ __pm_unregister(dev);
+ }
+ up(&pm_devs_lock);
+}
+
+/**
+ * pm_send - send request to a single device
+ * @dev: device to send to
+ * @rqst: power management request
+ * @data: data for the callback
+ *
+ * Issue a power management request to a given device. The
+ * %PM_SUSPEND and %PM_RESUME events are handled specially. The
+ * data field must hold the intended next state. No call is made
+ * if the state matches.
+ *
+ * BUGS: what stops two power management requests occurring in parallel
+ * and conflicting.
+ *
+ * WARNING: Calling pm_send directly is not generally recommended, in
+ * particular there is no locking against the pm_dev going away. The
+ * caller must maintain all needed locking or have 'inside knowledge'
+ * on the safety. Also remember that this function is not locked against
+ * pm_unregister. This means that you must handle SMP races on callback
+ * execution and unload yourself.
+ */
+
+static int pm_send(struct pm_dev *dev, pm_request_t rqst, void *data)
+{
+ int status = 0;
+ unsigned long prev_state, next_state;
+
+ if (in_interrupt())
+ BUG();
+
+ switch (rqst) {
+ case PM_SUSPEND:
+ case PM_RESUME:
+ prev_state = dev->state;
+ next_state = (unsigned long) data;
+ if (prev_state != next_state) {
+ if (dev->callback)
+ status = (*dev->callback)(dev, rqst, data);
+ if (!status) {
+ dev->state = next_state;
+ dev->prev_state = prev_state;
+ }
+ }
+ else {
+ dev->prev_state = prev_state;
+ }
+ break;
+ default:
+ if (dev->callback)
+ status = (*dev->callback)(dev, rqst, data);
+ break;
+ }
+ return status;
+}
+
+/*
+ * Undo incomplete request
+ */
+static void pm_undo_all(struct pm_dev *last)
+{
+ struct list_head *entry = last->entry.prev;
+ while (entry != &pm_devs) {
+ struct pm_dev *dev = list_entry(entry, struct pm_dev, entry);
+ if (dev->state != dev->prev_state) {
+ /* previous state was zero (running) resume or
+ * previous state was non-zero (suspended) suspend
+ */
+ pm_request_t undo = (dev->prev_state
+ ? PM_SUSPEND:PM_RESUME);
+ pm_send(dev, undo, (void*) dev->prev_state);
+ }
+ entry = entry->prev;
+ }
+}
+
+/**
+ * pm_send_all - send request to all managed devices
+ * @rqst: power management request
+ * @data: data for the callback
+ *
+ * Issue a power management request to a all devices. The
+ * %PM_SUSPEND events are handled specially. Any device is
+ * permitted to fail a suspend by returning a non zero (error)
+ * value from its callback function. If any device vetoes a
+ * suspend request then all other devices that have suspended
+ * during the processing of this request are restored to their
+ * previous state.
+ *
+ * WARNING: This function takes the pm_devs_lock. The lock is not dropped until
+ * the callbacks have completed. This prevents races against pm locking
+ * functions, races against module unload pm_unregister code. It does
+ * mean however that you must not issue pm_ functions within the callback
+ * or you will deadlock and users will hate you.
+ *
+ * Zero is returned on success. If a suspend fails then the status
+ * from the device that vetoes the suspend is returned.
+ *
+ * BUGS: what stops two power management requests occurring in parallel
+ * and conflicting.
+ */
+
+int pm_send_all(pm_request_t rqst, void *data)
+{
+ struct list_head *entry;
+
+ down(&pm_devs_lock);
+ entry = pm_devs.next;
+ while (entry != &pm_devs) {
+ struct pm_dev *dev = list_entry(entry, struct pm_dev, entry);
+ if (dev->callback) {
+ int status = pm_send(dev, rqst, data);
+ if (status) {
+ /* return devices to previous state on
+ * failed suspend request
+ */
+ if (rqst == PM_SUSPEND)
+ pm_undo_all(dev);
+ up(&pm_devs_lock);
+ return status;
+ }
+ }
+ entry = entry->next;
+ }
+ up(&pm_devs_lock);
+ return 0;
+}
+
+EXPORT_SYMBOL(pm_register);
+EXPORT_SYMBOL(pm_unregister);
+EXPORT_SYMBOL(pm_unregister_all);
+EXPORT_SYMBOL(pm_send_all);
+EXPORT_SYMBOL(pm_active);
+
+

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