/*
* 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();
thaw_processes();
enable_nonboot_cpus();
if (pm_ops && pm_ops->finish)
pm_ops->finish(state);
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);
