| /* |
| * 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 <linux/console.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; |
| } |
| |
| suspend_console(); |
| 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; |
| } |
| |
| |
| 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(); |
| resume_console(); |
| 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 (state < PM_SUSPEND_MAX && *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); |