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/suspend.h> 25 #include <linux/syscore_ops.h> 26 #include <trace/events/power.h> 27 28 #include "power.h" 29 30 const char *const pm_states[PM_SUSPEND_MAX] = { 31 [PM_SUSPEND_STANDBY] = "standby", 32 [PM_SUSPEND_MEM] = "mem", 33 }; 34 35 static const struct platform_suspend_ops *suspend_ops; 36 37 /** 38 * suspend_set_ops - Set the global suspend method table. 39 * @ops: Pointer to ops structure. 40 */ 41 void suspend_set_ops(const struct platform_suspend_ops *ops) 42 { 43 mutex_lock(&pm_mutex); 44 suspend_ops = ops; 45 mutex_unlock(&pm_mutex); 46 } 47 EXPORT_SYMBOL_GPL(suspend_set_ops); 48 49 bool valid_state(suspend_state_t state) 50 { 51 /* 52 * All states need lowlevel support and need to be valid to the lowlevel 53 * implementation, no valid callback implies that none are valid. 54 */ 55 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state); 56 } 57 58 /** 59 * suspend_valid_only_mem - generic memory-only valid callback 60 * 61 * Platform drivers that implement mem suspend only and only need 62 * to check for that in their .valid callback can use this instead 63 * of rolling their own .valid callback. 64 */ 65 int suspend_valid_only_mem(suspend_state_t state) 66 { 67 return state == PM_SUSPEND_MEM; 68 } 69 EXPORT_SYMBOL_GPL(suspend_valid_only_mem); 70 71 static int suspend_test(int level) 72 { 73 #ifdef CONFIG_PM_DEBUG 74 if (pm_test_level == level) { 75 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n"); 76 mdelay(5000); 77 return 1; 78 } 79 #endif /* !CONFIG_PM_DEBUG */ 80 return 0; 81 } 82 83 /** 84 * suspend_prepare - Do prep work before entering low-power state. 85 * 86 * This is common code that is called for each state that we're entering. 87 * Run suspend notifiers, allocate a console and stop all processes. 88 */ 89 static int suspend_prepare(void) 90 { 91 int error; 92 93 if (!suspend_ops || !suspend_ops->enter) 94 return -EPERM; 95 96 pm_prepare_console(); 97 98 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE); 99 if (error) 100 goto Finish; 101 102 error = usermodehelper_disable(); 103 if (error) 104 goto Finish; 105 106 error = suspend_freeze_processes(); 107 if (error) { 108 suspend_stats.failed_freeze++; 109 dpm_save_failed_step(SUSPEND_FREEZE); 110 } else 111 return 0; 112 113 suspend_thaw_processes(); 114 usermodehelper_enable(); 115 Finish: 116 pm_notifier_call_chain(PM_POST_SUSPEND); 117 pm_restore_console(); 118 return error; 119 } 120 121 /* default implementation */ 122 void __attribute__ ((weak)) arch_suspend_disable_irqs(void) 123 { 124 local_irq_disable(); 125 } 126 127 /* default implementation */ 128 void __attribute__ ((weak)) arch_suspend_enable_irqs(void) 129 { 130 local_irq_enable(); 131 } 132 133 /** 134 * suspend_enter - enter the desired system sleep state. 135 * @state: State to enter 136 * @wakeup: Returns information that suspend should not be entered again. 137 * 138 * This function should be called after devices have been suspended. 139 */ 140 static int suspend_enter(suspend_state_t state, bool *wakeup) 141 { 142 int error; 143 144 if (suspend_ops->prepare) { 145 error = suspend_ops->prepare(); 146 if (error) 147 goto Platform_finish; 148 } 149 150 error = dpm_suspend_noirq(PMSG_SUSPEND); 151 if (error) { 152 printk(KERN_ERR "PM: Some devices failed to power down\n"); 153 goto Platform_finish; 154 } 155 156 if (suspend_ops->prepare_late) { 157 error = suspend_ops->prepare_late(); 158 if (error) 159 goto Platform_wake; 160 } 161 162 if (suspend_test(TEST_PLATFORM)) 163 goto Platform_wake; 164 165 error = disable_nonboot_cpus(); 166 if (error || suspend_test(TEST_CPUS)) 167 goto Enable_cpus; 168 169 arch_suspend_disable_irqs(); 170 BUG_ON(!irqs_disabled()); 171 172 error = syscore_suspend(); 173 if (!error) { 174 *wakeup = pm_wakeup_pending(); 175 if (!(suspend_test(TEST_CORE) || *wakeup)) { 176 error = suspend_ops->enter(state); 177 events_check_enabled = false; 178 } 179 syscore_resume(); 180 } 181 182 arch_suspend_enable_irqs(); 183 BUG_ON(irqs_disabled()); 184 185 Enable_cpus: 186 enable_nonboot_cpus(); 187 188 Platform_wake: 189 if (suspend_ops->wake) 190 suspend_ops->wake(); 191 192 dpm_resume_noirq(PMSG_RESUME); 193 194 Platform_finish: 195 if (suspend_ops->finish) 196 suspend_ops->finish(); 197 198 return error; 199 } 200 201 /** 202 * suspend_devices_and_enter - suspend devices and enter the desired system 203 * sleep state. 204 * @state: state to enter 205 */ 206 int suspend_devices_and_enter(suspend_state_t state) 207 { 208 int error; 209 bool wakeup = false; 210 211 if (!suspend_ops) 212 return -ENOSYS; 213 214 trace_machine_suspend(state); 215 if (suspend_ops->begin) { 216 error = suspend_ops->begin(state); 217 if (error) 218 goto Close; 219 } 220 suspend_console(); 221 suspend_test_start(); 222 error = dpm_suspend_start(PMSG_SUSPEND); 223 if (error) { 224 printk(KERN_ERR "PM: Some devices failed to suspend\n"); 225 goto Recover_platform; 226 } 227 suspend_test_finish("suspend devices"); 228 if (suspend_test(TEST_DEVICES)) 229 goto Recover_platform; 230 231 do { 232 error = suspend_enter(state, &wakeup); 233 } while (!error && !wakeup 234 && suspend_ops->suspend_again && suspend_ops->suspend_again()); 235 236 Resume_devices: 237 suspend_test_start(); 238 dpm_resume_end(PMSG_RESUME); 239 suspend_test_finish("resume devices"); 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 - Do final work before exiting suspend sequence. 255 * 256 * Call platform code to clean up, restart processes, and free the 257 * console that we've allocated. This is not called for suspend-to-disk. 258 */ 259 static void suspend_finish(void) 260 { 261 suspend_thaw_processes(); 262 usermodehelper_enable(); 263 pm_notifier_call_chain(PM_POST_SUSPEND); 264 pm_restore_console(); 265 } 266 267 /** 268 * enter_state - Do common work of entering low-power state. 269 * @state: pm_state structure for state we're entering. 270 * 271 * Make sure we're the only ones trying to enter a sleep state. Fail 272 * if someone has beat us to it, since we don't want anything weird to 273 * happen when we wake up. 274 * Then, do the setup for suspend, enter the state, and cleaup (after 275 * we've woken up). 276 */ 277 int enter_state(suspend_state_t state) 278 { 279 int error; 280 281 if (!valid_state(state)) 282 return -ENODEV; 283 284 if (!mutex_trylock(&pm_mutex)) 285 return -EBUSY; 286 287 printk(KERN_INFO "PM: Syncing filesystems ... "); 288 sys_sync(); 289 printk("done.\n"); 290 291 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); 292 error = suspend_prepare(); 293 if (error) 294 goto Unlock; 295 296 if (suspend_test(TEST_FREEZER)) 297 goto Finish; 298 299 pr_debug("PM: Entering %s sleep\n", pm_states[state]); 300 pm_restrict_gfp_mask(); 301 error = suspend_devices_and_enter(state); 302 pm_restore_gfp_mask(); 303 304 Finish: 305 pr_debug("PM: Finishing wakeup.\n"); 306 suspend_finish(); 307 Unlock: 308 mutex_unlock(&pm_mutex); 309 return error; 310 } 311 312 /** 313 * pm_suspend - Externally visible function for suspending system. 314 * @state: Enumerated value of state to enter. 315 * 316 * Determine whether or not value is within range, get state 317 * structure, and enter (above). 318 */ 319 int pm_suspend(suspend_state_t state) 320 { 321 int ret; 322 if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX) { 323 ret = enter_state(state); 324 if (ret) { 325 suspend_stats.fail++; 326 dpm_save_failed_errno(ret); 327 } else 328 suspend_stats.success++; 329 return ret; 330 } 331 return -EINVAL; 332 } 333 EXPORT_SYMBOL(pm_suspend); 334