/* * kernel/power/suspend.c - Suspend to RAM and standby functionality. * * Copyright (c) 2003 Patrick Mochel * Copyright (c) 2003 Open Source Development Lab * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. * * This file is released under the GPLv2. */ #include <linux/string.h> #include <linux/delay.h> #include <linux/errno.h> #include <linux/init.h> #include <linux/console.h> #include <linux/cpu.h> #include <linux/syscalls.h> #include "power.h" const char *const pm_states[PM_SUSPEND_MAX] = { [PM_SUSPEND_STANDBY] = "standby", [PM_SUSPEND_MEM] = "mem", }; static struct platform_suspend_ops *suspend_ops; /** * suspend_set_ops - Set the global suspend method table. * @ops: Pointer to ops structure. */ void suspend_set_ops(struct platform_suspend_ops *ops) { mutex_lock(&pm_mutex); suspend_ops = ops; mutex_unlock(&pm_mutex); } bool valid_state(suspend_state_t state) { /* * All states need lowlevel support and need to be valid to the lowlevel * implementation, no valid callback implies that none are valid. */ return suspend_ops && suspend_ops->valid && suspend_ops->valid(state); } /** * suspend_valid_only_mem - generic memory-only valid callback * * Platform drivers that implement mem suspend only and only need * to check for that in their .valid callback can use this instead * of rolling their own .valid callback. */ int suspend_valid_only_mem(suspend_state_t state) { return state == PM_SUSPEND_MEM; } static int suspend_test(int level) { #ifdef CONFIG_PM_DEBUG if (pm_test_level == level) { printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n"); mdelay(5000); return 1; } #endif /* !CONFIG_PM_DEBUG */ return 0; } /** * suspend_prepare - Do prep work before entering low-power state. * * This is common code that is called for each state that we're entering. * Run suspend notifiers, allocate a console and stop all processes. */ static int suspend_prepare(void) { int error; if (!suspend_ops || !suspend_ops->enter) return -EPERM; pm_prepare_console(); error = pm_notifier_call_chain(PM_SUSPEND_PREPARE); if (error) goto Finish; error = usermodehelper_disable(); if (error) goto Finish; error = suspend_freeze_processes(); if (!error) return 0; suspend_thaw_processes(); usermodehelper_enable(); Finish: pm_notifier_call_chain(PM_POST_SUSPEND); pm_restore_console(); return error; } /* default implementation */ void __attribute__ ((weak)) arch_suspend_disable_irqs(void) { local_irq_disable(); } /* default implementation */ void __attribute__ ((weak)) arch_suspend_enable_irqs(void) { local_irq_enable(); } /** * suspend_enter - enter the desired system sleep state. * @state: state to enter * * This function should be called after devices have been suspended. */ static int suspend_enter(suspend_state_t state) { int error; if (suspend_ops->prepare) { error = suspend_ops->prepare(); if (error) return error; } error = dpm_suspend_noirq(PMSG_SUSPEND); if (error) { printk(KERN_ERR "PM: Some devices failed to power down\n"); goto Platfrom_finish; } if (suspend_ops->prepare_late) { error = suspend_ops->prepare_late(); if (error) goto Power_up_devices; } if (suspend_test(TEST_PLATFORM)) goto Platform_wake; error = disable_nonboot_cpus(); if (error || suspend_test(TEST_CPUS)) goto Enable_cpus; arch_suspend_disable_irqs(); BUG_ON(!irqs_disabled()); error = sysdev_suspend(PMSG_SUSPEND); if (!error) { if (!suspend_test(TEST_CORE)) error = suspend_ops->enter(state); sysdev_resume(); } arch_suspend_enable_irqs(); BUG_ON(irqs_disabled()); Enable_cpus: enable_nonboot_cpus(); Platform_wake: if (suspend_ops->wake) suspend_ops->wake(); Power_up_devices: dpm_resume_noirq(PMSG_RESUME); Platfrom_finish: if (suspend_ops->finish) suspend_ops->finish(); return error; } /** * suspend_devices_and_enter - suspend devices and enter the desired system * sleep state. * @state: state to enter */ int suspend_devices_and_enter(suspend_state_t state) { int error; if (!suspend_ops) return -ENOSYS; if (suspend_ops->begin) { error = suspend_ops->begin(state); if (error) goto Close; } suspend_console(); suspend_test_start(); error = dpm_suspend_start(PMSG_SUSPEND); if (error) { printk(KERN_ERR "PM: Some devices failed to suspend\n"); goto Recover_platform; } suspend_test_finish("suspend devices"); if (suspend_test(TEST_DEVICES)) goto Recover_platform; suspend_enter(state); Resume_devices: suspend_test_start(); dpm_resume_end(PMSG_RESUME); suspend_test_finish("resume devices"); resume_console(); Close: if (suspend_ops->end) suspend_ops->end(); return error; Recover_platform: if (suspend_ops->recover) suspend_ops->recover(); goto Resume_devices; } /** * suspend_finish - Do final work before exiting suspend sequence. * * 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(void) { suspend_thaw_processes(); usermodehelper_enable(); pm_notifier_call_chain(PM_POST_SUSPEND); pm_restore_console(); } /** * 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). */ int enter_state(suspend_state_t state) { int error; if (!valid_state(state)) return -ENODEV; if (!mutex_trylock(&pm_mutex)) return -EBUSY; printk(KERN_INFO "PM: Syncing filesystems ... "); sys_sync(); printk("done.\n"); pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); error = suspend_prepare(); if (error) goto Unlock; if (suspend_test(TEST_FREEZER)) goto Finish; pr_debug("PM: Entering %s sleep\n", pm_states[state]); error = suspend_devices_and_enter(state); Finish: pr_debug("PM: Finishing wakeup.\n"); suspend_finish(); Unlock: mutex_unlock(&pm_mutex); return error; } /** * pm_suspend - Externally visible function for suspending system. * @state: Enumerated 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; } EXPORT_SYMBOL(pm_suspend);