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/kmod.h> 16 #include <linux/console.h> 17 #include <linux/cpu.h> 18 #include <linux/syscalls.h> 19 #include <linux/gfp.h> 20 #include <linux/io.h> 21 #include <linux/kernel.h> 22 #include <linux/list.h> 23 #include <linux/mm.h> 24 #include <linux/slab.h> 25 #include <linux/export.h> 26 #include <linux/suspend.h> 27 #include <linux/syscore_ops.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: Pointer to ops structure. 42 */ 43 void suspend_set_ops(const struct platform_suspend_ops *ops) 44 { 45 mutex_lock(&pm_mutex); 46 suspend_ops = ops; 47 mutex_unlock(&pm_mutex); 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 64 * to check for that in their .valid callback can use this instead 65 * of rolling their own .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 - Do prep work before entering low-power state. 87 * 88 * This is common code that is called for each state that we're entering. 89 * Run suspend notifiers, allocate a console and stop all processes. 90 */ 91 static int suspend_prepare(void) 92 { 93 int error; 94 95 if (!suspend_ops || !suspend_ops->enter) 96 return -EPERM; 97 98 pm_prepare_console(); 99 100 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE); 101 if (error) 102 goto Finish; 103 104 error = usermodehelper_disable(); 105 if (error) 106 goto Finish; 107 108 error = suspend_freeze_processes(); 109 if (error) { 110 suspend_stats.failed_freeze++; 111 dpm_save_failed_step(SUSPEND_FREEZE); 112 } else 113 return 0; 114 115 suspend_thaw_processes(); 116 usermodehelper_enable(); 117 Finish: 118 pm_notifier_call_chain(PM_POST_SUSPEND); 119 pm_restore_console(); 120 return error; 121 } 122 123 /* default implementation */ 124 void __attribute__ ((weak)) arch_suspend_disable_irqs(void) 125 { 126 local_irq_disable(); 127 } 128 129 /* default implementation */ 130 void __attribute__ ((weak)) arch_suspend_enable_irqs(void) 131 { 132 local_irq_enable(); 133 } 134 135 /** 136 * suspend_enter - enter the desired system sleep state. 137 * @state: State to enter 138 * @wakeup: Returns information that suspend should not be entered again. 139 * 140 * This function should be called after devices have been suspended. 141 */ 142 static int suspend_enter(suspend_state_t state, bool *wakeup) 143 { 144 int error; 145 146 if (suspend_ops->prepare) { 147 error = suspend_ops->prepare(); 148 if (error) 149 goto Platform_finish; 150 } 151 152 error = dpm_suspend_noirq(PMSG_SUSPEND); 153 if (error) { 154 printk(KERN_ERR "PM: Some devices failed to power down\n"); 155 goto Platform_finish; 156 } 157 158 if (suspend_ops->prepare_late) { 159 error = suspend_ops->prepare_late(); 160 if (error) 161 goto Platform_wake; 162 } 163 164 if (suspend_test(TEST_PLATFORM)) 165 goto Platform_wake; 166 167 error = disable_nonboot_cpus(); 168 if (error || suspend_test(TEST_CPUS)) 169 goto Enable_cpus; 170 171 arch_suspend_disable_irqs(); 172 BUG_ON(!irqs_disabled()); 173 174 error = syscore_suspend(); 175 if (!error) { 176 *wakeup = pm_wakeup_pending(); 177 if (!(suspend_test(TEST_CORE) || *wakeup)) { 178 error = suspend_ops->enter(state); 179 events_check_enabled = false; 180 } 181 syscore_resume(); 182 } 183 184 arch_suspend_enable_irqs(); 185 BUG_ON(irqs_disabled()); 186 187 Enable_cpus: 188 enable_nonboot_cpus(); 189 190 Platform_wake: 191 if (suspend_ops->wake) 192 suspend_ops->wake(); 193 194 dpm_resume_noirq(PMSG_RESUME); 195 196 Platform_finish: 197 if (suspend_ops->finish) 198 suspend_ops->finish(); 199 200 return error; 201 } 202 203 /** 204 * suspend_devices_and_enter - suspend devices and enter the desired system 205 * sleep state. 206 * @state: state to enter 207 */ 208 int suspend_devices_and_enter(suspend_state_t state) 209 { 210 int error; 211 bool wakeup = false; 212 213 if (!suspend_ops) 214 return -ENOSYS; 215 216 trace_machine_suspend(state); 217 if (suspend_ops->begin) { 218 error = suspend_ops->begin(state); 219 if (error) 220 goto Close; 221 } 222 suspend_console(); 223 suspend_test_start(); 224 error = dpm_suspend_start(PMSG_SUSPEND); 225 if (error) { 226 printk(KERN_ERR "PM: Some devices failed to suspend\n"); 227 goto Recover_platform; 228 } 229 suspend_test_finish("suspend devices"); 230 if (suspend_test(TEST_DEVICES)) 231 goto Recover_platform; 232 233 do { 234 error = suspend_enter(state, &wakeup); 235 } while (!error && !wakeup 236 && suspend_ops->suspend_again && suspend_ops->suspend_again()); 237 238 Resume_devices: 239 suspend_test_start(); 240 dpm_resume_end(PMSG_RESUME); 241 suspend_test_finish("resume devices"); 242 resume_console(); 243 Close: 244 if (suspend_ops->end) 245 suspend_ops->end(); 246 trace_machine_suspend(PWR_EVENT_EXIT); 247 return error; 248 249 Recover_platform: 250 if (suspend_ops->recover) 251 suspend_ops->recover(); 252 goto Resume_devices; 253 } 254 255 /** 256 * suspend_finish - Do final work before exiting suspend sequence. 257 * 258 * Call platform code to clean up, restart processes, and free the 259 * console that we've allocated. This is not called for suspend-to-disk. 260 */ 261 static void suspend_finish(void) 262 { 263 suspend_thaw_processes(); 264 usermodehelper_enable(); 265 pm_notifier_call_chain(PM_POST_SUSPEND); 266 pm_restore_console(); 267 } 268 269 /** 270 * enter_state - Do common work of entering low-power state. 271 * @state: pm_state structure for state we're entering. 272 * 273 * Make sure we're the only ones trying to enter a sleep state. Fail 274 * if someone has beat us to it, since we don't want anything weird to 275 * happen when we wake up. 276 * Then, do the setup for suspend, enter the state, and cleaup (after 277 * we've woken up). 278 */ 279 int enter_state(suspend_state_t state) 280 { 281 int error; 282 283 if (!valid_state(state)) 284 return -ENODEV; 285 286 if (!mutex_trylock(&pm_mutex)) 287 return -EBUSY; 288 289 printk(KERN_INFO "PM: Syncing filesystems ... "); 290 sys_sync(); 291 printk("done.\n"); 292 293 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); 294 error = suspend_prepare(); 295 if (error) 296 goto Unlock; 297 298 if (suspend_test(TEST_FREEZER)) 299 goto Finish; 300 301 pr_debug("PM: Entering %s sleep\n", pm_states[state]); 302 pm_restrict_gfp_mask(); 303 error = suspend_devices_and_enter(state); 304 pm_restore_gfp_mask(); 305 306 Finish: 307 pr_debug("PM: Finishing wakeup.\n"); 308 suspend_finish(); 309 Unlock: 310 mutex_unlock(&pm_mutex); 311 return error; 312 } 313 314 /** 315 * pm_suspend - Externally visible function for suspending system. 316 * @state: Enumerated value of state to enter. 317 * 318 * Determine whether or not value is within range, get state 319 * structure, and enter (above). 320 */ 321 int pm_suspend(suspend_state_t state) 322 { 323 int ret; 324 if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX) { 325 ret = enter_state(state); 326 if (ret) { 327 suspend_stats.fail++; 328 dpm_save_failed_errno(ret); 329 } else 330 suspend_stats.success++; 331 return ret; 332 } 333 return -EINVAL; 334 } 335 EXPORT_SYMBOL(pm_suspend); 336