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