/* * kernel/power/main.c - PM subsystem core functionality. * * Copyright (c) 2003 Patrick Mochel * Copyright (c) 2003 Open Source Development Lab * * This file is released under the GPLv2 * */ #include <linux/suspend.h> #include <linux/kobject.h> #include <linux/string.h> #include <linux/delay.h> #include <linux/errno.h> #include <linux/init.h> #include <linux/pm.h> #include "power.h" /*This is just an arbitrary number */ #define FREE_PAGE_NUMBER (100) DECLARE_MUTEX(pm_sem); struct pm_ops *pm_ops; suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN; /** * pm_set_ops - Set the global power method table. * @ops: Pointer to ops structure. */ void pm_set_ops(struct pm_ops * ops) { down(&pm_sem); pm_ops = ops; up(&pm_sem); } /** * suspend_prepare - Do prep work before entering low-power state. * @state: State we're entering. * * This is common code that is called for each state that we're * entering. Allocate a console, stop all processes, then make sure * the platform can enter the requested state. */ static int suspend_prepare(suspend_state_t state) { int error = 0; unsigned int free_pages; if (!pm_ops || !pm_ops->enter) return -EPERM; pm_prepare_console(); disable_nonboot_cpus(); if (num_online_cpus() != 1) { error = -EPERM; goto Enable_cpu; } if (freeze_processes()) { error = -EAGAIN; goto Thaw; } if ((free_pages = nr_free_pages()) < FREE_PAGE_NUMBER) { pr_debug("PM: free some memory\n"); shrink_all_memory(FREE_PAGE_NUMBER - free_pages); if (nr_free_pages() < FREE_PAGE_NUMBER) { error = -ENOMEM; printk(KERN_ERR "PM: No enough memory\n"); goto Thaw; } } if (pm_ops->prepare) { if ((error = pm_ops->prepare(state))) goto Thaw; } if ((error = device_suspend(PMSG_SUSPEND))) { printk(KERN_ERR "Some devices failed to suspend\n"); goto Finish; } return 0; Finish: if (pm_ops->finish) pm_ops->finish(state); Thaw: thaw_processes(); Enable_cpu: enable_nonboot_cpus(); pm_restore_console(); return error; } static int suspend_enter(suspend_state_t state) { int error = 0; unsigned long flags; local_irq_save(flags); if ((error = device_power_down(PMSG_SUSPEND))) { printk(KERN_ERR "Some devices failed to power down\n"); goto Done; } error = pm_ops->enter(state); device_power_up(); Done: local_irq_restore(flags); return error; } /** * suspend_finish - Do final work before exiting suspend sequence. * @state: State we're coming out of. * * Call platform code to clean up, restart processes, and free the * console that we've allocated. This is not called for suspend-to-disk. */ static void suspend_finish(suspend_state_t state) { device_resume(); if (pm_ops && pm_ops->finish) pm_ops->finish(state); thaw_processes(); enable_nonboot_cpus(); pm_restore_console(); } static char *pm_states[PM_SUSPEND_MAX] = { [PM_SUSPEND_STANDBY] = "standby", [PM_SUSPEND_MEM] = "mem", #ifdef CONFIG_SOFTWARE_SUSPEND [PM_SUSPEND_DISK] = "disk", #endif }; static inline int valid_state(suspend_state_t state) { /* Suspend-to-disk does not really need low-level support. * It can work with reboot if needed. */ if (state == PM_SUSPEND_DISK) return 1; if (pm_ops && pm_ops->valid && !pm_ops->valid(state)) return 0; return 1; } /** * enter_state - Do common work of entering low-power state. * @state: pm_state structure for state we're entering. * * Make sure we're the only ones trying to enter a sleep state. Fail * if someone has beat us to it, since we don't want anything weird to * happen when we wake up. * Then, do the setup for suspend, enter the state, and cleaup (after * we've woken up). */ static int enter_state(suspend_state_t state) { int error; if (!valid_state(state)) return -ENODEV; if (down_trylock(&pm_sem)) return -EBUSY; if (state == PM_SUSPEND_DISK) { error = pm_suspend_disk(); goto Unlock; } pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); if ((error = suspend_prepare(state))) goto Unlock; pr_debug("PM: Entering %s sleep\n", pm_states[state]); error = suspend_enter(state); pr_debug("PM: Finishing wakeup.\n"); suspend_finish(state); Unlock: up(&pm_sem); return error; } /* * This is main interface to the outside world. It needs to be * called from process context. */ int software_suspend(void) { return enter_state(PM_SUSPEND_DISK); } /** * pm_suspend - Externally visible function for suspending system. * @state: Enumarted value of state to enter. * * Determine whether or not value is within range, get state * structure, and enter (above). */ int pm_suspend(suspend_state_t state) { if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX) return enter_state(state); return -EINVAL; } decl_subsys(power,NULL,NULL); /** * state - control system power state. * * show() returns what states are supported, which is hard-coded to * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and * 'disk' (Suspend-to-Disk). * * store() accepts one of those strings, translates it into the * proper enumerated value, and initiates a suspend transition. */ static ssize_t state_show(struct subsystem * subsys, char * buf) { int i; char * s = buf; for (i = 0; i < PM_SUSPEND_MAX; i++) { if (pm_states[i] && valid_state(i)) s += sprintf(s,"%s ", pm_states[i]); } s += sprintf(s,"\n"); return (s - buf); } static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n) { suspend_state_t state = PM_SUSPEND_STANDBY; char ** s; char *p; int error; int len; p = memchr(buf, '\n', n); len = p ? p - buf : n; for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { if (*s && !strncmp(buf, *s, len)) break; } if (*s) error = enter_state(state); else error = -EINVAL; return error ? error : n; } power_attr(state); static struct attribute * g[] = { &state_attr.attr, NULL, }; static struct attribute_group attr_group = { .attrs = g, }; static int __init pm_init(void) { int error = subsystem_register(&power_subsys); if (!error) error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group); return error; } core_initcall(pm_init);