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