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 return 0; 109 110 suspend_thaw_processes(); 111 usermodehelper_enable(); 112 Finish: 113 pm_notifier_call_chain(PM_POST_SUSPEND); 114 pm_restore_console(); 115 return error; 116 } 117 118 /* default implementation */ 119 void __attribute__ ((weak)) arch_suspend_disable_irqs(void) 120 { 121 local_irq_disable(); 122 } 123 124 /* default implementation */ 125 void __attribute__ ((weak)) arch_suspend_enable_irqs(void) 126 { 127 local_irq_enable(); 128 } 129 130 /** 131 * suspend_enter - enter the desired system sleep state. 132 * @state: State to enter 133 * @wakeup: Returns information that suspend should not be entered again. 134 * 135 * This function should be called after devices have been suspended. 136 */ 137 static int suspend_enter(suspend_state_t state, bool *wakeup) 138 { 139 int error; 140 141 if (suspend_ops->prepare) { 142 error = suspend_ops->prepare(); 143 if (error) 144 goto Platform_finish; 145 } 146 147 error = dpm_suspend_noirq(PMSG_SUSPEND); 148 if (error) { 149 printk(KERN_ERR "PM: Some devices failed to power down\n"); 150 goto Platform_finish; 151 } 152 153 if (suspend_ops->prepare_late) { 154 error = suspend_ops->prepare_late(); 155 if (error) 156 goto Platform_wake; 157 } 158 159 if (suspend_test(TEST_PLATFORM)) 160 goto Platform_wake; 161 162 error = disable_nonboot_cpus(); 163 if (error || suspend_test(TEST_CPUS)) 164 goto Enable_cpus; 165 166 arch_suspend_disable_irqs(); 167 BUG_ON(!irqs_disabled()); 168 169 error = syscore_suspend(); 170 if (!error) { 171 *wakeup = pm_wakeup_pending(); 172 if (!(suspend_test(TEST_CORE) || *wakeup)) { 173 error = suspend_ops->enter(state); 174 events_check_enabled = false; 175 } 176 syscore_resume(); 177 } 178 179 arch_suspend_enable_irqs(); 180 BUG_ON(irqs_disabled()); 181 182 Enable_cpus: 183 enable_nonboot_cpus(); 184 185 Platform_wake: 186 if (suspend_ops->wake) 187 suspend_ops->wake(); 188 189 dpm_resume_noirq(PMSG_RESUME); 190 191 Platform_finish: 192 if (suspend_ops->finish) 193 suspend_ops->finish(); 194 195 return error; 196 } 197 198 /** 199 * suspend_devices_and_enter - suspend devices and enter the desired system 200 * sleep state. 201 * @state: state to enter 202 */ 203 int suspend_devices_and_enter(suspend_state_t state) 204 { 205 int error; 206 bool wakeup = false; 207 208 if (!suspend_ops) 209 return -ENOSYS; 210 211 trace_machine_suspend(state); 212 if (suspend_ops->begin) { 213 error = suspend_ops->begin(state); 214 if (error) 215 goto Close; 216 } 217 suspend_console(); 218 suspend_test_start(); 219 error = dpm_suspend_start(PMSG_SUSPEND); 220 if (error) { 221 printk(KERN_ERR "PM: Some devices failed to suspend\n"); 222 goto Recover_platform; 223 } 224 suspend_test_finish("suspend devices"); 225 if (suspend_test(TEST_DEVICES)) 226 goto Recover_platform; 227 228 do { 229 error = suspend_enter(state, &wakeup); 230 } while (!error && !wakeup 231 && suspend_ops->suspend_again && suspend_ops->suspend_again()); 232 233 Resume_devices: 234 suspend_test_start(); 235 dpm_resume_end(PMSG_RESUME); 236 suspend_test_finish("resume devices"); 237 resume_console(); 238 Close: 239 if (suspend_ops->end) 240 suspend_ops->end(); 241 trace_machine_suspend(PWR_EVENT_EXIT); 242 return error; 243 244 Recover_platform: 245 if (suspend_ops->recover) 246 suspend_ops->recover(); 247 goto Resume_devices; 248 } 249 250 /** 251 * suspend_finish - Do final work before exiting suspend sequence. 252 * 253 * Call platform code to clean up, restart processes, and free the 254 * console that we've allocated. This is not called for suspend-to-disk. 255 */ 256 static void suspend_finish(void) 257 { 258 suspend_thaw_processes(); 259 usermodehelper_enable(); 260 pm_notifier_call_chain(PM_POST_SUSPEND); 261 pm_restore_console(); 262 } 263 264 /** 265 * enter_state - Do common work of entering low-power state. 266 * @state: pm_state structure for state we're entering. 267 * 268 * Make sure we're the only ones trying to enter a sleep state. Fail 269 * if someone has beat us to it, since we don't want anything weird to 270 * happen when we wake up. 271 * Then, do the setup for suspend, enter the state, and cleaup (after 272 * we've woken up). 273 */ 274 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 system. 311 * @state: Enumerated value of state to enter. 312 * 313 * Determine whether or not value is within range, get state 314 * structure, and enter (above). 315 */ 316 int pm_suspend(suspend_state_t state) 317 { 318 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX) 319 return enter_state(state); 320 return -EINVAL; 321 } 322 EXPORT_SYMBOL(pm_suspend); 323