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);
+
+