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