1 /* 2 * kernel/power/main.c - PM subsystem core functionality. 3 * 4 * Copyright (c) 2003 Patrick Mochel 5 * Copyright (c) 2003 Open Source Development Lab 6 * 7 * This file is released under the GPLv2 8 * 9 */ 10 11 #include <linux/module.h> 12 #include <linux/suspend.h> 13 #include <linux/kobject.h> 14 #include <linux/string.h> 15 #include <linux/delay.h> 16 #include <linux/errno.h> 17 #include <linux/init.h> 18 #include <linux/console.h> 19 #include <linux/cpu.h> 20 #include <linux/resume-trace.h> 21 #include <linux/freezer.h> 22 #include <linux/vmstat.h> 23 #include <linux/syscalls.h> 24 25 #include "power.h" 26 27 BLOCKING_NOTIFIER_HEAD(pm_chain_head); 28 29 DEFINE_MUTEX(pm_mutex); 30 31 #ifdef CONFIG_SUSPEND 32 33 /* This is just an arbitrary number */ 34 #define FREE_PAGE_NUMBER (100) 35 36 static struct platform_suspend_ops *suspend_ops; 37 38 /** 39 * suspend_set_ops - Set the global suspend method table. 40 * @ops: Pointer to ops structure. 41 */ 42 43 void suspend_set_ops(struct platform_suspend_ops *ops) 44 { 45 mutex_lock(&pm_mutex); 46 suspend_ops = ops; 47 mutex_unlock(&pm_mutex); 48 } 49 50 /** 51 * suspend_valid_only_mem - generic memory-only valid callback 52 * 53 * Platform drivers that implement mem suspend only and only need 54 * to check for that in their .valid callback can use this instead 55 * of rolling their own .valid callback. 56 */ 57 int suspend_valid_only_mem(suspend_state_t state) 58 { 59 return state == PM_SUSPEND_MEM; 60 } 61 62 /** 63 * suspend_prepare - Do prep work before entering low-power state. 64 * 65 * This is common code that is called for each state that we're entering. 66 * Run suspend notifiers, allocate a console and stop all processes. 67 */ 68 static int suspend_prepare(void) 69 { 70 int error; 71 unsigned int free_pages; 72 73 if (!suspend_ops || !suspend_ops->enter) 74 return -EPERM; 75 76 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE); 77 if (error) 78 goto Finish; 79 80 pm_prepare_console(); 81 82 if (freeze_processes()) { 83 error = -EAGAIN; 84 goto Thaw; 85 } 86 87 free_pages = global_page_state(NR_FREE_PAGES); 88 if (free_pages < FREE_PAGE_NUMBER) { 89 pr_debug("PM: free some memory\n"); 90 shrink_all_memory(FREE_PAGE_NUMBER - free_pages); 91 if (nr_free_pages() < FREE_PAGE_NUMBER) { 92 error = -ENOMEM; 93 printk(KERN_ERR "PM: No enough memory\n"); 94 } 95 } 96 if (!error) 97 return 0; 98 99 Thaw: 100 thaw_processes(); 101 pm_restore_console(); 102 Finish: 103 pm_notifier_call_chain(PM_POST_SUSPEND); 104 return error; 105 } 106 107 /* default implementation */ 108 void __attribute__ ((weak)) arch_suspend_disable_irqs(void) 109 { 110 local_irq_disable(); 111 } 112 113 /* default implementation */ 114 void __attribute__ ((weak)) arch_suspend_enable_irqs(void) 115 { 116 local_irq_enable(); 117 } 118 119 /** 120 * suspend_enter - enter the desired system sleep state. 121 * @state: state to enter 122 * 123 * This function should be called after devices have been suspended. 124 */ 125 static int suspend_enter(suspend_state_t state) 126 { 127 int error = 0; 128 129 arch_suspend_disable_irqs(); 130 BUG_ON(!irqs_disabled()); 131 132 if ((error = device_power_down(PMSG_SUSPEND))) { 133 printk(KERN_ERR "Some devices failed to power down\n"); 134 goto Done; 135 } 136 error = suspend_ops->enter(state); 137 device_power_up(); 138 Done: 139 arch_suspend_enable_irqs(); 140 BUG_ON(irqs_disabled()); 141 return error; 142 } 143 144 /** 145 * suspend_devices_and_enter - suspend devices and enter the desired system sleep 146 * state. 147 * @state: state to enter 148 */ 149 int suspend_devices_and_enter(suspend_state_t state) 150 { 151 int error; 152 153 if (!suspend_ops) 154 return -ENOSYS; 155 156 if (suspend_ops->set_target) { 157 error = suspend_ops->set_target(state); 158 if (error) 159 return error; 160 } 161 suspend_console(); 162 error = device_suspend(PMSG_SUSPEND); 163 if (error) { 164 printk(KERN_ERR "Some devices failed to suspend\n"); 165 goto Resume_console; 166 } 167 if (suspend_ops->prepare) { 168 error = suspend_ops->prepare(); 169 if (error) 170 goto Resume_devices; 171 } 172 error = disable_nonboot_cpus(); 173 if (!error) 174 suspend_enter(state); 175 176 enable_nonboot_cpus(); 177 if (suspend_ops->finish) 178 suspend_ops->finish(); 179 Resume_devices: 180 device_resume(); 181 Resume_console: 182 resume_console(); 183 return error; 184 } 185 186 /** 187 * suspend_finish - Do final work before exiting suspend sequence. 188 * 189 * Call platform code to clean up, restart processes, and free the 190 * console that we've allocated. This is not called for suspend-to-disk. 191 */ 192 static void suspend_finish(void) 193 { 194 thaw_processes(); 195 pm_restore_console(); 196 pm_notifier_call_chain(PM_POST_SUSPEND); 197 } 198 199 200 201 202 static const char * const pm_states[PM_SUSPEND_MAX] = { 203 [PM_SUSPEND_STANDBY] = "standby", 204 [PM_SUSPEND_MEM] = "mem", 205 }; 206 207 static inline int valid_state(suspend_state_t state) 208 { 209 /* All states need lowlevel support and need to be valid 210 * to the lowlevel implementation, no valid callback 211 * implies that none are valid. */ 212 if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state)) 213 return 0; 214 return 1; 215 } 216 217 218 /** 219 * enter_state - Do common work of entering low-power state. 220 * @state: pm_state structure for state we're entering. 221 * 222 * Make sure we're the only ones trying to enter a sleep state. Fail 223 * if someone has beat us to it, since we don't want anything weird to 224 * happen when we wake up. 225 * Then, do the setup for suspend, enter the state, and cleaup (after 226 * we've woken up). 227 */ 228 static int enter_state(suspend_state_t state) 229 { 230 int error; 231 232 if (!valid_state(state)) 233 return -ENODEV; 234 235 if (!mutex_trylock(&pm_mutex)) 236 return -EBUSY; 237 238 printk("Syncing filesystems ... "); 239 sys_sync(); 240 printk("done.\n"); 241 242 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); 243 if ((error = suspend_prepare())) 244 goto Unlock; 245 246 pr_debug("PM: Entering %s sleep\n", pm_states[state]); 247 error = suspend_devices_and_enter(state); 248 249 pr_debug("PM: Finishing wakeup.\n"); 250 suspend_finish(); 251 Unlock: 252 mutex_unlock(&pm_mutex); 253 return error; 254 } 255 256 257 /** 258 * pm_suspend - Externally visible function for suspending system. 259 * @state: Enumerated value of state to enter. 260 * 261 * Determine whether or not value is within range, get state 262 * structure, and enter (above). 263 */ 264 265 int pm_suspend(suspend_state_t state) 266 { 267 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX) 268 return enter_state(state); 269 return -EINVAL; 270 } 271 272 EXPORT_SYMBOL(pm_suspend); 273 274 #endif /* CONFIG_SUSPEND */ 275 276 decl_subsys(power,NULL,NULL); 277 278 279 /** 280 * state - control system power state. 281 * 282 * show() returns what states are supported, which is hard-coded to 283 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 284 * 'disk' (Suspend-to-Disk). 285 * 286 * store() accepts one of those strings, translates it into the 287 * proper enumerated value, and initiates a suspend transition. 288 */ 289 290 static ssize_t state_show(struct kset *kset, char *buf) 291 { 292 char *s = buf; 293 #ifdef CONFIG_SUSPEND 294 int i; 295 296 for (i = 0; i < PM_SUSPEND_MAX; i++) { 297 if (pm_states[i] && valid_state(i)) 298 s += sprintf(s,"%s ", pm_states[i]); 299 } 300 #endif 301 #ifdef CONFIG_HIBERNATION 302 s += sprintf(s, "%s\n", "disk"); 303 #else 304 if (s != buf) 305 /* convert the last space to a newline */ 306 *(s-1) = '\n'; 307 #endif 308 return (s - buf); 309 } 310 311 static ssize_t state_store(struct kset *kset, const char *buf, size_t n) 312 { 313 #ifdef CONFIG_SUSPEND 314 suspend_state_t state = PM_SUSPEND_STANDBY; 315 const char * const *s; 316 #endif 317 char *p; 318 int len; 319 int error = -EINVAL; 320 321 p = memchr(buf, '\n', n); 322 len = p ? p - buf : n; 323 324 /* First, check if we are requested to hibernate */ 325 if (len == 4 && !strncmp(buf, "disk", len)) { 326 error = hibernate(); 327 goto Exit; 328 } 329 330 #ifdef CONFIG_SUSPEND 331 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) { 332 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) 333 break; 334 } 335 if (state < PM_SUSPEND_MAX && *s) 336 error = enter_state(state); 337 #endif 338 339 Exit: 340 return error ? error : n; 341 } 342 343 power_attr(state); 344 345 #ifdef CONFIG_PM_TRACE 346 int pm_trace_enabled; 347 348 static ssize_t pm_trace_show(struct kset *kset, char *buf) 349 { 350 return sprintf(buf, "%d\n", pm_trace_enabled); 351 } 352 353 static ssize_t 354 pm_trace_store(struct kset *kset, const char *buf, size_t n) 355 { 356 int val; 357 358 if (sscanf(buf, "%d", &val) == 1) { 359 pm_trace_enabled = !!val; 360 return n; 361 } 362 return -EINVAL; 363 } 364 365 power_attr(pm_trace); 366 367 static struct attribute * g[] = { 368 &state_attr.attr, 369 &pm_trace_attr.attr, 370 NULL, 371 }; 372 #else 373 static struct attribute * g[] = { 374 &state_attr.attr, 375 NULL, 376 }; 377 #endif /* CONFIG_PM_TRACE */ 378 379 static struct attribute_group attr_group = { 380 .attrs = g, 381 }; 382 383 384 static int __init pm_init(void) 385 { 386 int error = subsystem_register(&power_subsys); 387 if (!error) 388 error = sysfs_create_group(&power_subsys.kobj,&attr_group); 389 return error; 390 } 391 392 core_initcall(pm_init); 393