1 /* 2 * kernel/power/suspend.c - Suspend to RAM and standby functionality. 3 * 4 * Copyright (c) 2003 Patrick Mochel 5 * Copyright (c) 2003 Open Source Development Lab 6 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. 7 * 8 * This file is released under the GPLv2. 9 */ 10 11 #include <linux/string.h> 12 #include <linux/delay.h> 13 #include <linux/errno.h> 14 #include <linux/init.h> 15 #include <linux/console.h> 16 #include <linux/cpu.h> 17 #include <linux/syscalls.h> 18 #include <linux/gfp.h> 19 #include <linux/io.h> 20 #include <linux/kernel.h> 21 #include <linux/list.h> 22 #include <linux/mm.h> 23 #include <linux/slab.h> 24 #include <linux/export.h> 25 #include <linux/suspend.h> 26 #include <linux/syscore_ops.h> 27 #include <linux/ftrace.h> 28 #include <trace/events/power.h> 29 #include <linux/compiler.h> 30 31 #include "power.h" 32 33 const char *const pm_states[PM_SUSPEND_MAX] = { 34 [PM_SUSPEND_FREEZE] = "freeze", 35 [PM_SUSPEND_STANDBY] = "standby", 36 [PM_SUSPEND_MEM] = "mem", 37 }; 38 39 static const struct platform_suspend_ops *suspend_ops; 40 41 static bool need_suspend_ops(suspend_state_t state) 42 { 43 return state > PM_SUSPEND_FREEZE; 44 } 45 46 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head); 47 static bool suspend_freeze_wake; 48 49 static void freeze_begin(void) 50 { 51 suspend_freeze_wake = false; 52 } 53 54 static void freeze_enter(void) 55 { 56 wait_event(suspend_freeze_wait_head, suspend_freeze_wake); 57 } 58 59 void freeze_wake(void) 60 { 61 suspend_freeze_wake = true; 62 wake_up(&suspend_freeze_wait_head); 63 } 64 EXPORT_SYMBOL_GPL(freeze_wake); 65 66 /** 67 * suspend_set_ops - Set the global suspend method table. 68 * @ops: Suspend operations to use. 69 */ 70 void suspend_set_ops(const struct platform_suspend_ops *ops) 71 { 72 lock_system_sleep(); 73 suspend_ops = ops; 74 unlock_system_sleep(); 75 } 76 EXPORT_SYMBOL_GPL(suspend_set_ops); 77 78 bool valid_state(suspend_state_t state) 79 { 80 if (state == PM_SUSPEND_FREEZE) { 81 #ifdef CONFIG_PM_DEBUG 82 if (pm_test_level != TEST_NONE && 83 pm_test_level != TEST_FREEZER && 84 pm_test_level != TEST_DEVICES && 85 pm_test_level != TEST_PLATFORM) { 86 printk(KERN_WARNING "Unsupported pm_test mode for " 87 "freeze state, please choose " 88 "none/freezer/devices/platform.\n"); 89 return false; 90 } 91 #endif 92 return true; 93 } 94 /* 95 * PM_SUSPEND_STANDBY and PM_SUSPEND_MEMORY states need lowlevel 96 * support and need to be valid to the lowlevel 97 * implementation, no valid callback implies that none are valid. 98 */ 99 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state); 100 } 101 102 /** 103 * suspend_valid_only_mem - Generic memory-only valid callback. 104 * 105 * Platform drivers that implement mem suspend only and only need to check for 106 * that in their .valid() callback can use this instead of rolling their own 107 * .valid() callback. 108 */ 109 int suspend_valid_only_mem(suspend_state_t state) 110 { 111 return state == PM_SUSPEND_MEM; 112 } 113 EXPORT_SYMBOL_GPL(suspend_valid_only_mem); 114 115 static int suspend_test(int level) 116 { 117 #ifdef CONFIG_PM_DEBUG 118 if (pm_test_level == level) { 119 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n"); 120 mdelay(5000); 121 return 1; 122 } 123 #endif /* !CONFIG_PM_DEBUG */ 124 return 0; 125 } 126 127 /** 128 * suspend_prepare - Prepare for entering system sleep state. 129 * 130 * Common code run for every system sleep state that can be entered (except for 131 * hibernation). Run suspend notifiers, allocate the "suspend" console and 132 * freeze processes. 133 */ 134 static int suspend_prepare(suspend_state_t state) 135 { 136 int error; 137 138 if (need_suspend_ops(state) && (!suspend_ops || !suspend_ops->enter)) 139 return -EPERM; 140 141 pm_prepare_console(); 142 143 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE); 144 if (error) 145 goto Finish; 146 147 error = suspend_freeze_processes(); 148 if (!error) 149 return 0; 150 151 suspend_stats.failed_freeze++; 152 dpm_save_failed_step(SUSPEND_FREEZE); 153 Finish: 154 pm_notifier_call_chain(PM_POST_SUSPEND); 155 pm_restore_console(); 156 return error; 157 } 158 159 /* default implementation */ 160 void __weak arch_suspend_disable_irqs(void) 161 { 162 local_irq_disable(); 163 } 164 165 /* default implementation */ 166 void __weak arch_suspend_enable_irqs(void) 167 { 168 local_irq_enable(); 169 } 170 171 /** 172 * suspend_enter - Make the system enter the given sleep state. 173 * @state: System sleep state to enter. 174 * @wakeup: Returns information that the sleep state should not be re-entered. 175 * 176 * This function should be called after devices have been suspended. 177 */ 178 static int suspend_enter(suspend_state_t state, bool *wakeup) 179 { 180 int error; 181 182 if (need_suspend_ops(state) && suspend_ops->prepare) { 183 error = suspend_ops->prepare(); 184 if (error) 185 goto Platform_finish; 186 } 187 188 error = dpm_suspend_end(PMSG_SUSPEND); 189 if (error) { 190 printk(KERN_ERR "PM: Some devices failed to power down\n"); 191 goto Platform_finish; 192 } 193 194 if (need_suspend_ops(state) && suspend_ops->prepare_late) { 195 error = suspend_ops->prepare_late(); 196 if (error) 197 goto Platform_wake; 198 } 199 200 if (suspend_test(TEST_PLATFORM)) 201 goto Platform_wake; 202 203 /* 204 * PM_SUSPEND_FREEZE equals 205 * frozen processes + suspended devices + idle processors. 206 * Thus we should invoke freeze_enter() soon after 207 * all the devices are suspended. 208 */ 209 if (state == PM_SUSPEND_FREEZE) { 210 freeze_enter(); 211 goto Platform_wake; 212 } 213 214 ftrace_stop(); 215 error = disable_nonboot_cpus(); 216 if (error || suspend_test(TEST_CPUS)) 217 goto Enable_cpus; 218 219 arch_suspend_disable_irqs(); 220 BUG_ON(!irqs_disabled()); 221 222 error = syscore_suspend(); 223 if (!error) { 224 *wakeup = pm_wakeup_pending(); 225 if (!(suspend_test(TEST_CORE) || *wakeup)) { 226 error = suspend_ops->enter(state); 227 events_check_enabled = false; 228 } 229 syscore_resume(); 230 } 231 232 arch_suspend_enable_irqs(); 233 BUG_ON(irqs_disabled()); 234 235 Enable_cpus: 236 enable_nonboot_cpus(); 237 ftrace_start(); 238 239 Platform_wake: 240 if (need_suspend_ops(state) && suspend_ops->wake) 241 suspend_ops->wake(); 242 243 dpm_resume_start(PMSG_RESUME); 244 245 Platform_finish: 246 if (need_suspend_ops(state) && suspend_ops->finish) 247 suspend_ops->finish(); 248 249 return error; 250 } 251 252 /** 253 * suspend_devices_and_enter - Suspend devices and enter system sleep state. 254 * @state: System sleep state to enter. 255 */ 256 int suspend_devices_and_enter(suspend_state_t state) 257 { 258 int error; 259 bool wakeup = false; 260 261 if (need_suspend_ops(state) && !suspend_ops) 262 return -ENOSYS; 263 264 trace_machine_suspend(state); 265 if (need_suspend_ops(state) && suspend_ops->begin) { 266 error = suspend_ops->begin(state); 267 if (error) 268 goto Close; 269 } 270 suspend_console(); 271 suspend_test_start(); 272 error = dpm_suspend_start(PMSG_SUSPEND); 273 if (error) { 274 pr_err("PM: Some devices failed to suspend, or early wake event detected\n"); 275 goto Recover_platform; 276 } 277 suspend_test_finish("suspend devices"); 278 if (suspend_test(TEST_DEVICES)) 279 goto Recover_platform; 280 281 do { 282 error = suspend_enter(state, &wakeup); 283 } while (!error && !wakeup && need_suspend_ops(state) 284 && suspend_ops->suspend_again && suspend_ops->suspend_again()); 285 286 Resume_devices: 287 suspend_test_start(); 288 dpm_resume_end(PMSG_RESUME); 289 suspend_test_finish("resume devices"); 290 resume_console(); 291 Close: 292 if (need_suspend_ops(state) && suspend_ops->end) 293 suspend_ops->end(); 294 trace_machine_suspend(PWR_EVENT_EXIT); 295 return error; 296 297 Recover_platform: 298 if (need_suspend_ops(state) && suspend_ops->recover) 299 suspend_ops->recover(); 300 goto Resume_devices; 301 } 302 303 /** 304 * suspend_finish - Clean up before finishing the suspend sequence. 305 * 306 * Call platform code to clean up, restart processes, and free the console that 307 * we've allocated. This routine is not called for hibernation. 308 */ 309 static void suspend_finish(void) 310 { 311 suspend_thaw_processes(); 312 pm_notifier_call_chain(PM_POST_SUSPEND); 313 pm_restore_console(); 314 } 315 316 /** 317 * enter_state - Do common work needed to enter system sleep state. 318 * @state: System sleep state to enter. 319 * 320 * Make sure that no one else is trying to put the system into a sleep state. 321 * Fail if that's not the case. Otherwise, prepare for system suspend, make the 322 * system enter the given sleep state and clean up after wakeup. 323 */ 324 static int enter_state(suspend_state_t state) 325 { 326 int error; 327 328 if (!valid_state(state)) 329 return -ENODEV; 330 331 if (!mutex_trylock(&pm_mutex)) 332 return -EBUSY; 333 334 if (state == PM_SUSPEND_FREEZE) 335 freeze_begin(); 336 337 printk(KERN_INFO "PM: Syncing filesystems ... "); 338 sys_sync(); 339 printk("done.\n"); 340 341 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); 342 error = suspend_prepare(state); 343 if (error) 344 goto Unlock; 345 346 if (suspend_test(TEST_FREEZER)) 347 goto Finish; 348 349 pr_debug("PM: Entering %s sleep\n", pm_states[state]); 350 pm_restrict_gfp_mask(); 351 error = suspend_devices_and_enter(state); 352 pm_restore_gfp_mask(); 353 354 Finish: 355 pr_debug("PM: Finishing wakeup.\n"); 356 suspend_finish(); 357 Unlock: 358 mutex_unlock(&pm_mutex); 359 return error; 360 } 361 362 /** 363 * pm_suspend - Externally visible function for suspending the system. 364 * @state: System sleep state to enter. 365 * 366 * Check if the value of @state represents one of the supported states, 367 * execute enter_state() and update system suspend statistics. 368 */ 369 int pm_suspend(suspend_state_t state) 370 { 371 int error; 372 373 if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX) 374 return -EINVAL; 375 376 error = enter_state(state); 377 if (error) { 378 suspend_stats.fail++; 379 dpm_save_failed_errno(error); 380 } else { 381 suspend_stats.success++; 382 } 383 return error; 384 } 385 EXPORT_SYMBOL(pm_suspend); 386