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);
+
+