kernel/power/suspend.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
0004  *
0005  * Copyright (c) 2003 Patrick Mochel
0006  * Copyright (c) 2003 Open Source Development Lab
0007  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
0008  */
0009
0010 #define pr_fmt(fmt) "PM: " fmt
0011
0012 #include <linux/string.h>
0013 #include <linux/delay.h>
0014 #include <linux/errno.h>
0015 #include <linux/init.h>
0016 #include <linux/console.h>
0017 #include <linux/cpu.h>
0018 #include <linux/cpuidle.h>
0019 #include <linux/gfp.h>
0020 #include <linux/io.h>
0021 #include <linux/kernel.h>
0022 #include <linux/list.h>
0023 #include <linux/mm.h>
0024 #include <linux/slab.h>
0025 #include <linux/export.h>
0026 #include <linux/suspend.h>
0027 #include <linux/syscore_ops.h>
0028 #include <linux/swait.h>
0029 #include <linux/ftrace.h>
0030 #include <trace/events/power.h>
0031 #include <linux/compiler.h>
0032 #include <linux/moduleparam.h>
0033
0034 #include "power.h"
0035
0036 const char * const pm_labels[] = {
0037     [PM_SUSPEND_TO_IDLE] = "freeze",
0038     [PM_SUSPEND_STANDBY] = "standby",
0039     [PM_SUSPEND_MEM] = "mem",
0040 };
0041 const char *pm_states[PM_SUSPEND_MAX];
0042 static const char * const mem_sleep_labels[] = {
0043     [PM_SUSPEND_TO_IDLE] = "s2idle",
0044     [PM_SUSPEND_STANDBY] = "shallow",
0045     [PM_SUSPEND_MEM] = "deep",
0046 };
0047 const char *mem_sleep_states[PM_SUSPEND_MAX];
0048
0049 suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
0050 suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
0051 suspend_state_t pm_suspend_target_state;
0052 EXPORT_SYMBOL_GPL(pm_suspend_target_state);
0053
0054 unsigned int pm_suspend_global_flags;
0055 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
0056
0057 static const struct platform_suspend_ops *suspend_ops;
0058 static const struct platform_s2idle_ops *s2idle_ops;
0059 static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head);
0060
0061 enum s2idle_states __read_mostly s2idle_state;
0062 static DEFINE_RAW_SPINLOCK(s2idle_lock);
0063
0064 /**
0065  * pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend.
0066  *
0067  * Return 'true' if suspend-to-idle has been selected as the default system
0068  * suspend method.
0069  */
0070 bool pm_suspend_default_s2idle(void)
0071 {
0072     return mem_sleep_current == PM_SUSPEND_TO_IDLE;
0073 }
0074 EXPORT_SYMBOL_GPL(pm_suspend_default_s2idle);
0075
0076 void s2idle_set_ops(const struct platform_s2idle_ops *ops)
0077 {
0078     lock_system_sleep();
0079     s2idle_ops = ops;
0080     unlock_system_sleep();
0081 }
0082
0083 static void s2idle_begin(void)
0084 {
0085     s2idle_state = S2IDLE_STATE_NONE;
0086 }
0087
0088 static void s2idle_enter(void)
0089 {
0090     trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
0091
0092     raw_spin_lock_irq(&s2idle_lock);
0093     if (pm_wakeup_pending())
0094         goto out;
0095
0096     s2idle_state = S2IDLE_STATE_ENTER;
0097     raw_spin_unlock_irq(&s2idle_lock);
0098
0099     cpus_read_lock();
0100
0101     /* Push all the CPUs into the idle loop. */
0102     wake_up_all_idle_cpus();
0103     /* Make the current CPU wait so it can enter the idle loop too. */
0104     swait_event_exclusive(s2idle_wait_head,
0105             s2idle_state == S2IDLE_STATE_WAKE);
0106
0107     cpus_read_unlock();
0108
0109     raw_spin_lock_irq(&s2idle_lock);
0110
0111  out:
0112     s2idle_state = S2IDLE_STATE_NONE;
0113     raw_spin_unlock_irq(&s2idle_lock);
0114
0115     trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
0116 }
0117
0118 static void s2idle_loop(void)
0119 {
0120     pm_pr_dbg("suspend-to-idle\n");
0121
0122     /*
0123      * Suspend-to-idle equals:
0124      * frozen processes + suspended devices + idle processors.
0125      * Thus s2idle_enter() should be called right after all devices have
0126      * been suspended.
0127      *
0128      * Wakeups during the noirq suspend of devices may be spurious, so try
0129      * to avoid them upfront.
0130      */
0131     for (;;) {
0132         if (s2idle_ops && s2idle_ops->wake) {
0133             if (s2idle_ops->wake())
0134                 break;
0135         } else if (pm_wakeup_pending()) {
0136             break;
0137         }
0138
0139         s2idle_enter();
0140     }
0141
0142     pm_pr_dbg("resume from suspend-to-idle\n");
0143 }
0144
0145 void s2idle_wake(void)
0146 {
0147     unsigned long flags;
0148
0149     raw_spin_lock_irqsave(&s2idle_lock, flags);
0150     if (s2idle_state > S2IDLE_STATE_NONE) {
0151         s2idle_state = S2IDLE_STATE_WAKE;
0152         swake_up_one(&s2idle_wait_head);
0153     }
0154     raw_spin_unlock_irqrestore(&s2idle_lock, flags);
0155 }
0156 EXPORT_SYMBOL_GPL(s2idle_wake);
0157
0158 static bool valid_state(suspend_state_t state)
0159 {
0160     /*
0161      * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level
0162      * support and need to be valid to the low-level implementation.
0163      *
0164      * No ->valid() or ->enter() callback implies that none are valid.
0165      */
0166     return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&
0167         suspend_ops->enter;
0168 }
0169
0170 void __init pm_states_init(void)
0171 {
0172     /* "mem" and "freeze" are always present in /sys/power/state. */
0173     pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
0174     pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
0175     /*
0176      * Suspend-to-idle should be supported even without any suspend_ops,
0177      * initialize mem_sleep_states[] accordingly here.
0178      */
0179     mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
0180 }
0181
0182 static int __init mem_sleep_default_setup(char *str)
0183 {
0184     suspend_state_t state;
0185
0186     for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
0187         if (mem_sleep_labels[state] &&
0188             !strcmp(str, mem_sleep_labels[state])) {
0189             mem_sleep_default = state;
0190             break;
0191         }
0192
0193     return 1;
0194 }
0195 __setup("mem_sleep_default=", mem_sleep_default_setup);
0196
0197 /**
0198  * suspend_set_ops - Set the global suspend method table.
0199  * @ops: Suspend operations to use.
0200  */
0201 void suspend_set_ops(const struct platform_suspend_ops *ops)
0202 {
0203     lock_system_sleep();
0204
0205     suspend_ops = ops;
0206
0207     if (valid_state(PM_SUSPEND_STANDBY)) {
0208         mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
0209         pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
0210         if (mem_sleep_default == PM_SUSPEND_STANDBY)
0211             mem_sleep_current = PM_SUSPEND_STANDBY;
0212     }
0213     if (valid_state(PM_SUSPEND_MEM)) {
0214         mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
0215         if (mem_sleep_default >= PM_SUSPEND_MEM)
0216             mem_sleep_current = PM_SUSPEND_MEM;
0217     }
0218
0219     unlock_system_sleep();
0220 }
0221 EXPORT_SYMBOL_GPL(suspend_set_ops);
0222
0223 /**
0224  * suspend_valid_only_mem - Generic memory-only valid callback.
0225  * @state: Target system sleep state.
0226  *
0227  * Platform drivers that implement mem suspend only and only need to check for
0228  * that in their .valid() callback can use this instead of rolling their own
0229  * .valid() callback.
0230  */
0231 int suspend_valid_only_mem(suspend_state_t state)
0232 {
0233     return state == PM_SUSPEND_MEM;
0234 }
0235 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
0236
0237 static bool sleep_state_supported(suspend_state_t state)
0238 {
0239     return state == PM_SUSPEND_TO_IDLE ||
0240            (valid_state(state) && !cxl_mem_active());
0241 }
0242
0243 static int platform_suspend_prepare(suspend_state_t state)
0244 {
0245     return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
0246         suspend_ops->prepare() : 0;
0247 }
0248
0249 static int platform_suspend_prepare_late(suspend_state_t state)
0250 {
0251     return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
0252         s2idle_ops->prepare() : 0;
0253 }
0254
0255 static int platform_suspend_prepare_noirq(suspend_state_t state)
0256 {
0257     if (state == PM_SUSPEND_TO_IDLE)
0258         return s2idle_ops && s2idle_ops->prepare_late ?
0259             s2idle_ops->prepare_late() : 0;
0260
0261     return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;
0262 }
0263
0264 static void platform_resume_noirq(suspend_state_t state)
0265 {
0266     if (state == PM_SUSPEND_TO_IDLE) {
0267         if (s2idle_ops && s2idle_ops->restore_early)
0268             s2idle_ops->restore_early();
0269     } else if (suspend_ops->wake) {
0270         suspend_ops->wake();
0271     }
0272 }
0273
0274 static void platform_resume_early(suspend_state_t state)
0275 {
0276     if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
0277         s2idle_ops->restore();
0278 }
0279
0280 static void platform_resume_finish(suspend_state_t state)
0281 {
0282     if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
0283         suspend_ops->finish();
0284 }
0285
0286 static int platform_suspend_begin(suspend_state_t state)
0287 {
0288     if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
0289         return s2idle_ops->begin();
0290     else if (suspend_ops && suspend_ops->begin)
0291         return suspend_ops->begin(state);
0292     else
0293         return 0;
0294 }
0295
0296 static void platform_resume_end(suspend_state_t state)
0297 {
0298     if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
0299         s2idle_ops->end();
0300     else if (suspend_ops && suspend_ops->end)
0301         suspend_ops->end();
0302 }
0303
0304 static void platform_recover(suspend_state_t state)
0305 {
0306     if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
0307         suspend_ops->recover();
0308 }
0309
0310 static bool platform_suspend_again(suspend_state_t state)
0311 {
0312     return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
0313         suspend_ops->suspend_again() : false;
0314 }
0315
0316 #ifdef CONFIG_PM_DEBUG
0317 static unsigned int pm_test_delay = 5;
0318 module_param(pm_test_delay, uint, 0644);
0319 MODULE_PARM_DESC(pm_test_delay,
0320          "Number of seconds to wait before resuming from suspend test");
0321 #endif
0322
0323 static int suspend_test(int level)
0324 {
0325 #ifdef CONFIG_PM_DEBUG
0326     if (pm_test_level == level) {
0327         pr_info("suspend debug: Waiting for %d second(s).\n",
0328                 pm_test_delay);
0329         mdelay(pm_test_delay * 1000);
0330         return 1;
0331     }
0332 #endif /* !CONFIG_PM_DEBUG */
0333     return 0;
0334 }
0335
0336 /**
0337  * suspend_prepare - Prepare for entering system sleep state.
0338  * @state: Target system sleep state.
0339  *
0340  * Common code run for every system sleep state that can be entered (except for
0341  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
0342  * freeze processes.
0343  */
0344 static int suspend_prepare(suspend_state_t state)
0345 {
0346     int error;
0347
0348     if (!sleep_state_supported(state))
0349         return -EPERM;
0350
0351     pm_prepare_console();
0352
0353     error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
0354     if (error)
0355         goto Restore;
0356
0357     trace_suspend_resume(TPS("freeze_processes"), 0, true);
0358     error = suspend_freeze_processes();
0359     trace_suspend_resume(TPS("freeze_processes"), 0, false);
0360     if (!error)
0361         return 0;
0362
0363     suspend_stats.failed_freeze++;
0364     dpm_save_failed_step(SUSPEND_FREEZE);
0365     pm_notifier_call_chain(PM_POST_SUSPEND);
0366  Restore:
0367     pm_restore_console();
0368     return error;
0369 }
0370
0371 /* default implementation */
0372 void __weak arch_suspend_disable_irqs(void)
0373 {
0374     local_irq_disable();
0375 }
0376
0377 /* default implementation */
0378 void __weak arch_suspend_enable_irqs(void)
0379 {
0380     local_irq_enable();
0381 }
0382
0383 /**
0384  * suspend_enter - Make the system enter the given sleep state.
0385  * @state: System sleep state to enter.
0386  * @wakeup: Returns information that the sleep state should not be re-entered.
0387  *
0388  * This function should be called after devices have been suspended.
0389  */
0390 static int suspend_enter(suspend_state_t state, bool *wakeup)
0391 {
0392     int error;
0393
0394     error = platform_suspend_prepare(state);
0395     if (error)
0396         goto Platform_finish;
0397
0398     error = dpm_suspend_late(PMSG_SUSPEND);
0399     if (error) {
0400         pr_err("late suspend of devices failed\n");
0401         goto Platform_finish;
0402     }
0403     error = platform_suspend_prepare_late(state);
0404     if (error)
0405         goto Devices_early_resume;
0406
0407     error = dpm_suspend_noirq(PMSG_SUSPEND);
0408     if (error) {
0409         pr_err("noirq suspend of devices failed\n");
0410         goto Platform_early_resume;
0411     }
0412     error = platform_suspend_prepare_noirq(state);
0413     if (error)
0414         goto Platform_wake;
0415
0416     if (suspend_test(TEST_PLATFORM))
0417         goto Platform_wake;
0418
0419     if (state == PM_SUSPEND_TO_IDLE) {
0420         s2idle_loop();
0421         goto Platform_wake;
0422     }
0423
0424     error = pm_sleep_disable_secondary_cpus();
0425     if (error || suspend_test(TEST_CPUS))
0426         goto Enable_cpus;
0427
0428     arch_suspend_disable_irqs();
0429     BUG_ON(!irqs_disabled());
0430
0431     system_state = SYSTEM_SUSPEND;
0432
0433     error = syscore_suspend();
0434     if (!error) {
0435         *wakeup = pm_wakeup_pending();
0436         if (!(suspend_test(TEST_CORE) || *wakeup)) {
0437             trace_suspend_resume(TPS("machine_suspend"),
0438                 state, true);
0439             error = suspend_ops->enter(state);
0440             trace_suspend_resume(TPS("machine_suspend"),
0441                 state, false);
0442         } else if (*wakeup) {
0443             error = -EBUSY;
0444         }
0445         syscore_resume();
0446     }
0447
0448     system_state = SYSTEM_RUNNING;
0449
0450     arch_suspend_enable_irqs();
0451     BUG_ON(irqs_disabled());
0452
0453  Enable_cpus:
0454     pm_sleep_enable_secondary_cpus();
0455
0456  Platform_wake:
0457     platform_resume_noirq(state);
0458     dpm_resume_noirq(PMSG_RESUME);
0459
0460  Platform_early_resume:
0461     platform_resume_early(state);
0462
0463  Devices_early_resume:
0464     dpm_resume_early(PMSG_RESUME);
0465
0466  Platform_finish:
0467     platform_resume_finish(state);
0468     return error;
0469 }
0470
0471 /**
0472  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
0473  * @state: System sleep state to enter.
0474  */
0475 int suspend_devices_and_enter(suspend_state_t state)
0476 {
0477     int error;
0478     bool wakeup = false;
0479
0480     if (!sleep_state_supported(state))
0481         return -ENOSYS;
0482
0483     pm_suspend_target_state = state;
0484
0485     if (state == PM_SUSPEND_TO_IDLE)
0486         pm_set_suspend_no_platform();
0487
0488     error = platform_suspend_begin(state);
0489     if (error)
0490         goto Close;
0491
0492     suspend_console();
0493     suspend_test_start();
0494     error = dpm_suspend_start(PMSG_SUSPEND);
0495     if (error) {
0496         pr_err("Some devices failed to suspend, or early wake event detected\n");
0497         goto Recover_platform;
0498     }
0499     suspend_test_finish("suspend devices");
0500     if (suspend_test(TEST_DEVICES))
0501         goto Recover_platform;
0502
0503     do {
0504         error = suspend_enter(state, &wakeup);
0505     } while (!error && !wakeup && platform_suspend_again(state));
0506
0507  Resume_devices:
0508     suspend_test_start();
0509     dpm_resume_end(PMSG_RESUME);
0510     suspend_test_finish("resume devices");
0511     trace_suspend_resume(TPS("resume_console"), state, true);
0512     resume_console();
0513     trace_suspend_resume(TPS("resume_console"), state, false);
0514
0515  Close:
0516     platform_resume_end(state);
0517     pm_suspend_target_state = PM_SUSPEND_ON;
0518     return error;
0519
0520  Recover_platform:
0521     platform_recover(state);
0522     goto Resume_devices;
0523 }
0524
0525 /**
0526  * suspend_finish - Clean up before finishing the suspend sequence.
0527  *
0528  * Call platform code to clean up, restart processes, and free the console that
0529  * we've allocated. This routine is not called for hibernation.
0530  */
0531 static void suspend_finish(void)
0532 {
0533     suspend_thaw_processes();
0534     pm_notifier_call_chain(PM_POST_SUSPEND);
0535     pm_restore_console();
0536 }
0537
0538 /**
0539  * enter_state - Do common work needed to enter system sleep state.
0540  * @state: System sleep state to enter.
0541  *
0542  * Make sure that no one else is trying to put the system into a sleep state.
0543  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
0544  * system enter the given sleep state and clean up after wakeup.
0545  */
0546 static int enter_state(suspend_state_t state)
0547 {
0548     int error;
0549
0550     trace_suspend_resume(TPS("suspend_enter"), state, true);
0551     if (state == PM_SUSPEND_TO_IDLE) {
0552 #ifdef CONFIG_PM_DEBUG
0553         if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
0554             pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
0555             return -EAGAIN;
0556         }
0557 #endif
0558     } else if (!valid_state(state)) {
0559         return -EINVAL;
0560     }
0561     if (!mutex_trylock(&system_transition_mutex))
0562         return -EBUSY;
0563
0564     if (state == PM_SUSPEND_TO_IDLE)
0565         s2idle_begin();
0566
0567     if (sync_on_suspend_enabled) {
0568         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
0569         ksys_sync_helper();
0570         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
0571     }
0572
0573     pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
0574     pm_suspend_clear_flags();
0575     error = suspend_prepare(state);
0576     if (error)
0577         goto Unlock;
0578
0579     if (suspend_test(TEST_FREEZER))
0580         goto Finish;
0581
0582     trace_suspend_resume(TPS("suspend_enter"), state, false);
0583     pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
0584     pm_restrict_gfp_mask();
0585     error = suspend_devices_and_enter(state);
0586     pm_restore_gfp_mask();
0587
0588  Finish:
0589     events_check_enabled = false;
0590     pm_pr_dbg("Finishing wakeup.\n");
0591     suspend_finish();
0592  Unlock:
0593     mutex_unlock(&system_transition_mutex);
0594     return error;
0595 }
0596
0597 /**
0598  * pm_suspend - Externally visible function for suspending the system.
0599  * @state: System sleep state to enter.
0600  *
0601  * Check if the value of @state represents one of the supported states,
0602  * execute enter_state() and update system suspend statistics.
0603  */
0604 int pm_suspend(suspend_state_t state)
0605 {
0606     int error;
0607
0608     if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
0609         return -EINVAL;
0610
0611     pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
0612     error = enter_state(state);
0613     if (error) {
0614         suspend_stats.fail++;
0615         dpm_save_failed_errno(error);
0616     } else {
0617         suspend_stats.success++;
0618     }
0619     pr_info("suspend exit\n");
0620     return error;
0621 }
0622 EXPORT_SYMBOL(pm_suspend);