linux/kernel/power/main.c
Rafael J. Wysocki 8d98a690f5 swsusp: fix sysfs interface
The sysfs files /sys/power/disk and /sys/power/state do not work as
documented, since they allow the user to write only a few initial
characters of the input string to trigger the option (eg.  'echo pl >
/sys/power/disk' activates the platform mode of hibernation).  Fix it.

Special thanks to Peter Moulder <Peter.Moulder@infotech.monash.edu.au> for
pointing out the problem.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17 05:23:05 -07:00

358 lines
7.4 KiB
C

/*
* 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/module.h>
#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 <linux/console.h>
#include <linux/cpu.h>
#include <linux/resume-trace.h>
#include <linux/freezer.h>
#include <linux/vmstat.h>
#include "power.h"
/*This is just an arbitrary number */
#define FREE_PAGE_NUMBER (100)
DEFINE_MUTEX(pm_mutex);
struct pm_ops *pm_ops;
/**
* pm_set_ops - Set the global power method table.
* @ops: Pointer to ops structure.
*/
void pm_set_ops(struct pm_ops * ops)
{
mutex_lock(&pm_mutex);
pm_ops = ops;
mutex_unlock(&pm_mutex);
}
/**
* pm_valid_only_mem - generic memory-only valid callback
*
* pm_ops 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 pm_valid_only_mem(suspend_state_t state)
{
return state == PM_SUSPEND_MEM;
}
static inline void pm_finish(suspend_state_t state)
{
if (pm_ops->finish)
pm_ops->finish(state);
}
/**
* 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;
unsigned int free_pages;
if (!pm_ops || !pm_ops->enter)
return -EPERM;
pm_prepare_console();
if (freeze_processes()) {
error = -EAGAIN;
goto Thaw;
}
if ((free_pages = global_page_state(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;
}
}
suspend_console();
error = device_suspend(PMSG_SUSPEND);
if (error) {
printk(KERN_ERR "Some devices failed to suspend\n");
goto Resume_console;
}
if (pm_ops->prepare) {
if ((error = pm_ops->prepare(state)))
goto Resume_devices;
}
error = disable_nonboot_cpus();
if (!error)
return 0;
enable_nonboot_cpus();
pm_finish(state);
Resume_devices:
device_resume();
Resume_console:
resume_console();
Thaw:
thaw_processes();
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();
}
int suspend_enter(suspend_state_t state)
{
int error = 0;
arch_suspend_disable_irqs();
BUG_ON(!irqs_disabled());
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:
arch_suspend_enable_irqs();
BUG_ON(irqs_disabled());
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)
{
enable_nonboot_cpus();
pm_finish(state);
device_resume();
resume_console();
thaw_processes();
pm_restore_console();
}
static const char * const pm_states[PM_SUSPEND_MAX] = {
[PM_SUSPEND_STANDBY] = "standby",
[PM_SUSPEND_MEM] = "mem",
};
static inline int 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. */
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 (!mutex_trylock(&pm_mutex))
return -EBUSY;
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:
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);
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 kset *kset, 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]);
}
#ifdef CONFIG_SOFTWARE_SUSPEND
s += sprintf(s, "%s\n", "disk");
#else
if (s != buf)
/* convert the last space to a newline */
*(s-1) = '\n';
#endif
return (s - buf);
}
static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
{
suspend_state_t state = PM_SUSPEND_STANDBY;
const char * const *s;
char *p;
int error;
int len;
p = memchr(buf, '\n', n);
len = p ? p - buf : n;
/* First, check if we are requested to hibernate */
if (len == 4 && !strncmp(buf, "disk", len)) {
error = hibernate();
return error ? error : n;
}
for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
break;
}
if (state < PM_SUSPEND_MAX && *s)
error = enter_state(state);
else
error = -EINVAL;
return error ? error : n;
}
power_attr(state);
#ifdef CONFIG_PM_TRACE
int pm_trace_enabled;
static ssize_t pm_trace_show(struct kset *kset, char *buf)
{
return sprintf(buf, "%d\n", pm_trace_enabled);
}
static ssize_t
pm_trace_store(struct kset *kset, const char *buf, size_t n)
{
int val;
if (sscanf(buf, "%d", &val) == 1) {
pm_trace_enabled = !!val;
return n;
}
return -EINVAL;
}
power_attr(pm_trace);
static struct attribute * g[] = {
&state_attr.attr,
&pm_trace_attr.attr,
NULL,
};
#else
static struct attribute * g[] = {
&state_attr.attr,
NULL,
};
#endif /* CONFIG_PM_TRACE */
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.kobj,&attr_group);
return error;
}
core_initcall(pm_init);