1 // SPDX-License-Identifier: GPL-2.0-only
3  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
26 #include <linux/suspend.h>
66  * pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend.
68  * Return 'true' if suspend-to-idle has been selected as the default system
69  * suspend method.
100 	 * The s2idle_lock must be acquired before the pending wakeup check to  in s2idle_enter()
112 	/* Push all the CPUs into the idle loop. */  in s2idle_enter()
114 	/* Make the current CPU wait so it can enter the idle loop too. */  in s2idle_enter()
119 	 * Kick all CPUs to ensure that they resume their timers and restore  in s2idle_enter()
135 	pm_pr_dbg("suspend-to-idle\n");  in s2idle_loop()
138 	 * Suspend-to-idle equals:  in s2idle_loop()
139 	 * frozen processes + suspended devices + idle processors.  in s2idle_loop()
143 	 * Wakeups during the noirq suspend of devices may be spurious, so try  in s2idle_loop()
144 	 * to avoid them upfront.  in s2idle_loop()
147 		if (s2idle_ops && s2idle_ops->wake) {  in s2idle_loop()
148 			if (s2idle_ops->wake())  in s2idle_loop()
154 		if (s2idle_ops && s2idle_ops->check)  in s2idle_loop()
155 			s2idle_ops->check();  in s2idle_loop()
160 	pm_pr_dbg("resume from suspend-to-idle\n");  in s2idle_loop()
179 	 * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level  in valid_state()
180 	 * support and need to be valid to the low-level implementation.  in valid_state()
182 	 * No ->valid() or ->enter() callback implies that none are valid.  in valid_state()
184 	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&  in valid_state()
185 		suspend_ops->enter;  in valid_state()
194 	 * Suspend-to-idle should be supported even without any suspend_ops,  in pm_states_init()
217  * suspend_set_ops - Set the global suspend method table.
218  * @ops: Suspend operations to use.
245  * suspend_valid_only_mem - Generic memory-only valid callback.
248  * Platform drivers that implement mem suspend only and only need to check for
266 	return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?  in platform_suspend_prepare()
267 		suspend_ops->prepare() : 0;  in platform_suspend_prepare()
272 	return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?  in platform_suspend_prepare_late()
273 		s2idle_ops->prepare() : 0;  in platform_suspend_prepare_late()
279 		return s2idle_ops && s2idle_ops->prepare_late ?  in platform_suspend_prepare_noirq()
280 			s2idle_ops->prepare_late() : 0;  in platform_suspend_prepare_noirq()
282 	return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;  in platform_suspend_prepare_noirq()
288 		if (s2idle_ops && s2idle_ops->restore_early)  in platform_resume_noirq()
289 			s2idle_ops->restore_early();  in platform_resume_noirq()
290 	} else if (suspend_ops->wake) {  in platform_resume_noirq()
291 		suspend_ops->wake();  in platform_resume_noirq()
297 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)  in platform_resume_early()
298 		s2idle_ops->restore();  in platform_resume_early()
303 	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)  in platform_resume_finish()
304 		suspend_ops->finish();  in platform_resume_finish()
309 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)  in platform_suspend_begin()
310 		return s2idle_ops->begin();  in platform_suspend_begin()
311 	else if (suspend_ops && suspend_ops->begin)  in platform_suspend_begin()
312 		return suspend_ops->begin(state);  in platform_suspend_begin()
319 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)  in platform_resume_end()
320 		s2idle_ops->end();  in platform_resume_end()
321 	else if (suspend_ops && suspend_ops->end)  in platform_resume_end()
322 		suspend_ops->end();  in platform_resume_end()
327 	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)  in platform_recover()
328 		suspend_ops->recover();  in platform_recover()
333 	return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?  in platform_suspend_again()
334 		suspend_ops->suspend_again() : false;  in platform_suspend_again()
341 		 "Number of seconds to wait before resuming from suspend test");
348 		pr_info("suspend debug: Waiting for %d second(s).\n",  in suspend_test()
358  * suspend_prepare - Prepare for entering system sleep state.
362  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
370 		return -EPERM;  in suspend_prepare()
407  * suspend_enter - Make the system enter the given sleep state.
408  * @state: System sleep state to enter.
409  * @wakeup: Returns information that the sleep state should not be re-entered.
423 		pr_err("late suspend of devices failed\n");  in suspend_enter()
432 		pr_err("noirq suspend of devices failed\n");  in suspend_enter()
462 			error = suspend_ops->enter(state);  in suspend_enter()
466 			error = -EBUSY;  in suspend_enter()
495  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
496  * @state: System sleep state to enter.
504 		return -ENOSYS;  in suspend_devices_and_enter()
519 		pr_err("Some devices failed to suspend, or early wake event detected\n");  in suspend_devices_and_enter()
522 	suspend_test_finish("suspend devices");  in suspend_devices_and_enter()
549  * suspend_finish - Clean up before finishing the suspend sequence.
551  * Call platform code to clean up, restart processes, and free the console that
563  * enter_state - Do common work needed to enter system sleep state.
564  * @state: System sleep state to enter.
566  * Make sure that no one else is trying to put the system into a sleep state.
567  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
578 …pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n…  in enter_state()
579 			return -EAGAIN;  in enter_state()
583 		return -EINVAL;  in enter_state()
586 		return -EBUSY;  in enter_state()
620  * pm_suspend - Externally visible function for suspending the system.
621  * @state: System sleep state to enter.
624  * execute enter_state() and update system suspend statistics.
631 		return -EINVAL;  in pm_suspend()
633 	pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);  in pm_suspend()
636 	pr_info("suspend exit\n");  in pm_suspend()