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 20 #include "power.h" 21 22 const char *const pm_states[PM_SUSPEND_MAX] = { 23 [PM_SUSPEND_STANDBY] = "standby", 24 [PM_SUSPEND_MEM] = "mem", 25 }; 26 27 static struct platform_suspend_ops *suspend_ops; 28 29 /** 30 * suspend_set_ops - Set the global suspend method table. 31 * @ops: Pointer to ops structure. 32 */ 33 void suspend_set_ops(struct platform_suspend_ops *ops) 34 { 35 mutex_lock(&pm_mutex); 36 suspend_ops = ops; 37 mutex_unlock(&pm_mutex); 38 } 39 40 bool valid_state(suspend_state_t state) 41 { 42 /* 43 * All states need lowlevel support and need to be valid to the lowlevel 44 * implementation, no valid callback implies that none are valid. 45 */ 46 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state); 47 } 48 49 /** 50 * suspend_valid_only_mem - generic memory-only valid callback 51 * 52 * Platform drivers that implement mem suspend only and only need 53 * to check for that in their .valid callback can use this instead 54 * of rolling their own .valid callback. 55 */ 56 int suspend_valid_only_mem(suspend_state_t state) 57 { 58 return state == PM_SUSPEND_MEM; 59 } 60 61 static int suspend_test(int level) 62 { 63 #ifdef CONFIG_PM_DEBUG 64 if (pm_test_level == level) { 65 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n"); 66 mdelay(5000); 67 return 1; 68 } 69 #endif /* !CONFIG_PM_DEBUG */ 70 return 0; 71 } 72 73 /** 74 * suspend_prepare - Do prep work before entering low-power state. 75 * 76 * This is common code that is called for each state that we're entering. 77 * Run suspend notifiers, allocate a console and stop all processes. 78 */ 79 static int suspend_prepare(void) 80 { 81 int error; 82 83 if (!suspend_ops || !suspend_ops->enter) 84 return -EPERM; 85 86 pm_prepare_console(); 87 88 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE); 89 if (error) 90 goto Finish; 91 92 error = usermodehelper_disable(); 93 if (error) 94 goto Finish; 95 96 error = suspend_freeze_processes(); 97 if (!error) 98 return 0; 99 100 suspend_thaw_processes(); 101 usermodehelper_enable(); 102 Finish: 103 pm_notifier_call_chain(PM_POST_SUSPEND); 104 pm_restore_console(); 105 return error; 106 } 107 108 /* default implementation */ 109 void __attribute__ ((weak)) arch_suspend_disable_irqs(void) 110 { 111 local_irq_disable(); 112 } 113 114 /* default implementation */ 115 void __attribute__ ((weak)) arch_suspend_enable_irqs(void) 116 { 117 local_irq_enable(); 118 } 119 120 /** 121 * suspend_enter - enter the desired system sleep state. 122 * @state: state to enter 123 * 124 * This function should be called after devices have been suspended. 125 */ 126 static int suspend_enter(suspend_state_t state) 127 { 128 int error; 129 130 if (suspend_ops->prepare) { 131 error = suspend_ops->prepare(); 132 if (error) 133 return error; 134 } 135 136 error = dpm_suspend_noirq(PMSG_SUSPEND); 137 if (error) { 138 printk(KERN_ERR "PM: Some devices failed to power down\n"); 139 goto Platfrom_finish; 140 } 141 142 if (suspend_ops->prepare_late) { 143 error = suspend_ops->prepare_late(); 144 if (error) 145 goto Power_up_devices; 146 } 147 148 if (suspend_test(TEST_PLATFORM)) 149 goto Platform_wake; 150 151 error = disable_nonboot_cpus(); 152 if (error || suspend_test(TEST_CPUS)) 153 goto Enable_cpus; 154 155 arch_suspend_disable_irqs(); 156 BUG_ON(!irqs_disabled()); 157 158 error = sysdev_suspend(PMSG_SUSPEND); 159 if (!error) { 160 if (!suspend_test(TEST_CORE)) 161 error = suspend_ops->enter(state); 162 sysdev_resume(); 163 } 164 165 arch_suspend_enable_irqs(); 166 BUG_ON(irqs_disabled()); 167 168 Enable_cpus: 169 enable_nonboot_cpus(); 170 171 Platform_wake: 172 if (suspend_ops->wake) 173 suspend_ops->wake(); 174 175 Power_up_devices: 176 dpm_resume_noirq(PMSG_RESUME); 177 178 Platfrom_finish: 179 if (suspend_ops->finish) 180 suspend_ops->finish(); 181 182 return error; 183 } 184 185 /** 186 * suspend_devices_and_enter - suspend devices and enter the desired system 187 * sleep state. 188 * @state: state to enter 189 */ 190 int suspend_devices_and_enter(suspend_state_t state) 191 { 192 int error; 193 gfp_t saved_mask; 194 195 if (!suspend_ops) 196 return -ENOSYS; 197 198 if (suspend_ops->begin) { 199 error = suspend_ops->begin(state); 200 if (error) 201 goto Close; 202 } 203 suspend_console(); 204 saved_mask = clear_gfp_allowed_mask(GFP_IOFS); 205 suspend_test_start(); 206 error = dpm_suspend_start(PMSG_SUSPEND); 207 if (error) { 208 printk(KERN_ERR "PM: Some devices failed to suspend\n"); 209 goto Recover_platform; 210 } 211 suspend_test_finish("suspend devices"); 212 if (suspend_test(TEST_DEVICES)) 213 goto Recover_platform; 214 215 suspend_enter(state); 216 217 Resume_devices: 218 suspend_test_start(); 219 dpm_resume_end(PMSG_RESUME); 220 suspend_test_finish("resume devices"); 221 set_gfp_allowed_mask(saved_mask); 222 resume_console(); 223 Close: 224 if (suspend_ops->end) 225 suspend_ops->end(); 226 return error; 227 228 Recover_platform: 229 if (suspend_ops->recover) 230 suspend_ops->recover(); 231 goto Resume_devices; 232 } 233 234 /** 235 * suspend_finish - Do final work before exiting suspend sequence. 236 * 237 * Call platform code to clean up, restart processes, and free the 238 * console that we've allocated. This is not called for suspend-to-disk. 239 */ 240 static void suspend_finish(void) 241 { 242 suspend_thaw_processes(); 243 usermodehelper_enable(); 244 pm_notifier_call_chain(PM_POST_SUSPEND); 245 pm_restore_console(); 246 } 247 248 /** 249 * enter_state - Do common work of entering low-power state. 250 * @state: pm_state structure for state we're entering. 251 * 252 * Make sure we're the only ones trying to enter a sleep state. Fail 253 * if someone has beat us to it, since we don't want anything weird to 254 * happen when we wake up. 255 * Then, do the setup for suspend, enter the state, and cleaup (after 256 * we've woken up). 257 */ 258 int enter_state(suspend_state_t state) 259 { 260 int error; 261 262 if (!valid_state(state)) 263 return -ENODEV; 264 265 if (!mutex_trylock(&pm_mutex)) 266 return -EBUSY; 267 268 printk(KERN_INFO "PM: Syncing filesystems ... "); 269 sys_sync(); 270 printk("done.\n"); 271 272 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); 273 error = suspend_prepare(); 274 if (error) 275 goto Unlock; 276 277 if (suspend_test(TEST_FREEZER)) 278 goto Finish; 279 280 pr_debug("PM: Entering %s sleep\n", pm_states[state]); 281 error = suspend_devices_and_enter(state); 282 283 Finish: 284 pr_debug("PM: Finishing wakeup.\n"); 285 suspend_finish(); 286 Unlock: 287 mutex_unlock(&pm_mutex); 288 return error; 289 } 290 291 /** 292 * pm_suspend - Externally visible function for suspending system. 293 * @state: Enumerated value of state to enter. 294 * 295 * Determine whether or not value is within range, get state 296 * structure, and enter (above). 297 */ 298 int pm_suspend(suspend_state_t state) 299 { 300 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX) 301 return enter_state(state); 302 return -EINVAL; 303 } 304 EXPORT_SYMBOL(pm_suspend); 305