1 // SPDX-License-Identifier: GPL-2.0-only
3  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
26 #include <linux/suspend.h>
65  * pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend.
67  * Return 'true' if suspend-to-idle has been selected as the default system
68  * suspend method.
103 	/* Push all the CPUs into the idle loop. */  in s2idle_enter()
105 	/* Make the current CPU wait so it can enter the idle loop too. */  in s2idle_enter()
110 	 * Kick all CPUs to ensure that they resume their timers and restore  in s2idle_enter()
128 	pm_pr_dbg("suspend-to-idle\n");  in s2idle_loop()
131 	 * Suspend-to-idle equals:  in s2idle_loop()
132 	 * frozen processes + suspended devices + idle processors.  in s2idle_loop()
136 	 * Wakeups during the noirq suspend of devices may be spurious, so try  in s2idle_loop()
137 	 * to avoid them upfront.  in s2idle_loop()
140 		if (s2idle_ops && s2idle_ops->wake) {  in s2idle_loop()
141 			if (s2idle_ops->wake())  in s2idle_loop()
147 		if (s2idle_ops && s2idle_ops->check)  in s2idle_loop()
148 			s2idle_ops->check();  in s2idle_loop()
153 	pm_pr_dbg("resume from suspend-to-idle\n");  in s2idle_loop()
172 	 * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level  in valid_state()
173 	 * support and need to be valid to the low-level implementation.  in valid_state()
175 	 * No ->valid() or ->enter() callback implies that none are valid.  in valid_state()
177 	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&  in valid_state()
178 		suspend_ops->enter;  in valid_state()
187 	 * Suspend-to-idle should be supported even without any suspend_ops,  in pm_states_init()
210  * suspend_set_ops - Set the global suspend method table.
211  * @ops: Suspend operations to use.
238  * suspend_valid_only_mem - Generic memory-only valid callback.
241  * Platform drivers that implement mem suspend only and only need to check for
259 	return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?  in platform_suspend_prepare()
260 		suspend_ops->prepare() : 0;  in platform_suspend_prepare()
265 	return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?  in platform_suspend_prepare_late()
266 		s2idle_ops->prepare() : 0;  in platform_suspend_prepare_late()
272 		return s2idle_ops && s2idle_ops->prepare_late ?  in platform_suspend_prepare_noirq()
273 			s2idle_ops->prepare_late() : 0;  in platform_suspend_prepare_noirq()
275 	return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;  in platform_suspend_prepare_noirq()
281 		if (s2idle_ops && s2idle_ops->restore_early)  in platform_resume_noirq()
282 			s2idle_ops->restore_early();  in platform_resume_noirq()
283 	} else if (suspend_ops->wake) {  in platform_resume_noirq()
284 		suspend_ops->wake();  in platform_resume_noirq()
290 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)  in platform_resume_early()
291 		s2idle_ops->restore();  in platform_resume_early()
296 	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)  in platform_resume_finish()
297 		suspend_ops->finish();  in platform_resume_finish()
302 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)  in platform_suspend_begin()
303 		return s2idle_ops->begin();  in platform_suspend_begin()
304 	else if (suspend_ops && suspend_ops->begin)  in platform_suspend_begin()
305 		return suspend_ops->begin(state);  in platform_suspend_begin()
312 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)  in platform_resume_end()
313 		s2idle_ops->end();  in platform_resume_end()
314 	else if (suspend_ops && suspend_ops->end)  in platform_resume_end()
315 		suspend_ops->end();  in platform_resume_end()
320 	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)  in platform_recover()
321 		suspend_ops->recover();  in platform_recover()
326 	return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?  in platform_suspend_again()
327 		suspend_ops->suspend_again() : false;  in platform_suspend_again()
334 		 "Number of seconds to wait before resuming from suspend test");
341 		pr_info("suspend debug: Waiting for %d second(s).\n",  in suspend_test()
351  * suspend_prepare - Prepare for entering system sleep state.
355  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
363 		return -EPERM;  in suspend_prepare()
397  * suspend_enter - Make the system enter the given sleep state.
398  * @state: System sleep state to enter.
399  * @wakeup: Returns information that the sleep state should not be re-entered.
413 		pr_err("late suspend of devices failed\n");  in suspend_enter()
422 		pr_err("noirq suspend of devices failed\n");  in suspend_enter()
452 			error = suspend_ops->enter(state);  in suspend_enter()
456 			error = -EBUSY;  in suspend_enter()
485  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
486  * @state: System sleep state to enter.
494 		return -ENOSYS;  in suspend_devices_and_enter()
509 		pr_err("Some devices failed to suspend, or early wake event detected\n");  in suspend_devices_and_enter()
512 	suspend_test_finish("suspend devices");  in suspend_devices_and_enter()
539  * suspend_finish - Clean up before finishing the suspend sequence.
541  * Call platform code to clean up, restart processes, and free the console that
552  * enter_state - Do common work needed to enter system sleep state.
553  * @state: System sleep state to enter.
555  * Make sure that no one else is trying to put the system into a sleep state.
556  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
567 …pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n…  in enter_state()
568 			return -EAGAIN;  in enter_state()
572 		return -EINVAL;  in enter_state()
575 		return -EBUSY;  in enter_state()
611  * pm_suspend - Externally visible function for suspending the system.
612  * @state: System sleep state to enter.
615  * execute enter_state() and update system suspend statistics.
622 		return -EINVAL;  in pm_suspend()
624 	pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);  in pm_suspend()
627 	pr_info("suspend exit\n");  in pm_suspend()