From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-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! --- kernel/power/pm.c | 265 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 265 insertions(+) create mode 100644 kernel/power/pm.c (limited to 'kernel/power/pm.c') diff --git a/kernel/power/pm.c b/kernel/power/pm.c new file mode 100644 index 00000000000..61deda04e39 --- /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 +#include +#include +#include +#include +#include +#include + +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); + + -- cgit v1.2.3