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