1 // SPDX-License-Identifier: GPL-2.0
3  * This file contains functions which emulate a local clock-event
6  * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
7  * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
8  * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
20 #include "tick-internal.h"
23  * Broadcast support for broken x86 hardware, where the local apic
24  * timer stops in C3 state.
79 	if ((newdev->features & CLOCK_EVT_FEAT_DUMMY) ||  in tick_check_broadcast_device()
80 	    (newdev->features & CLOCK_EVT_FEAT_PERCPU) ||  in tick_check_broadcast_device()
81 	    (newdev->features & CLOCK_EVT_FEAT_C3STOP))  in tick_check_broadcast_device()
85 	    !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))  in tick_check_broadcast_device()
88 	return !curdev || newdev->rating > curdev->rating;  in tick_check_broadcast_device()
101 	if (!try_module_get(dev->owner))  in tick_install_broadcast_device()
106 		cur->event_handler = clockevents_handle_noop;  in tick_install_broadcast_device()
118 	if (dev->features & CLOCK_EVT_FEAT_ONESHOT)  in tick_install_broadcast_device()
132 	int ret = -ENODEV;  in tick_broadcast_update_freq()
145 	pr_crit_once("Failed to broadcast timer tick. Some CPUs may be unresponsive.\n");  in err_broadcast()
150 	if (!dev->broadcast)  in tick_device_setup_broadcast_func()
151 		dev->broadcast = tick_broadcast;  in tick_device_setup_broadcast_func()
152 	if (!dev->broadcast) {  in tick_device_setup_broadcast_func()
154 			     dev->name);  in tick_device_setup_broadcast_func()
155 		dev->broadcast = err_broadcast;  in tick_device_setup_broadcast_func()
175 	 * the cpu local device.  in tick_device_uses_broadcast()
178 		dev->event_handler = tick_handle_periodic;  in tick_device_uses_broadcast()
191 		if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))  in tick_device_uses_broadcast()
210 			 * state affected device to stop. Let the  in tick_device_uses_broadcast()
233 			if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER))  in tick_device_uses_broadcast()
248 	struct clock_event_device *evt = td->evtdev;  in tick_receive_broadcast()
251 		return -ENODEV;  in tick_receive_broadcast()
253 	if (!evt->event_handler)  in tick_receive_broadcast()
254 		return -EINVAL;  in tick_receive_broadcast()
256 	evt->event_handler(evt);  in tick_receive_broadcast()
268 	bool local = false;  in tick_do_broadcast()  local
278 		 * We only run the local handler, if the broadcast  in tick_do_broadcast()
282 		 * local timer_interrupt()  in tick_do_broadcast()
289 		local = !(bc->features & CLOCK_EVT_FEAT_HRTIMER);  in tick_do_broadcast()
300 		td->evtdev->broadcast(mask);  in tick_do_broadcast()
302 	return local;  in tick_do_broadcast()
307  * - invoke the broadcast handlers
334 		ktime_t next = ktime_add(dev->next_event, tick_period);  in tick_handle_periodic_broadcast()
341 	 * We run the handler of the local cpu after dropping  in tick_handle_periodic_broadcast()
346 		td->evtdev->event_handler(td->evtdev);  in tick_handle_periodic_broadcast()
350  * tick_broadcast_control - Enable/disable or force broadcast mode
354  * might stop. Note: TICK_BROADCAST_FORCE cannot be undone.
363 	/* Protects also the local clockevent device. */  in tick_broadcast_control()
366 	dev = td->evtdev;  in tick_broadcast_control()
371 	if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))  in tick_broadcast_control()
389 			 * Only shutdown the cpu local device, if:  in tick_broadcast_control()
391 			 * - the broadcast device exists  in tick_broadcast_control()
392 			 * - the broadcast device is not a hrtimer based one  in tick_broadcast_control()
393 			 * - the broadcast device is in periodic mode to  in tick_broadcast_control()
396 			if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER) &&  in tick_broadcast_control()
436 		dev->event_handler = tick_handle_periodic;  in tick_set_periodic_handler()
438 		dev->event_handler = tick_handle_periodic_broadcast;  in tick_set_periodic_handler()
555 	if (!(bc->features & CLOCK_EVT_FEAT_DYNIRQ))  in tick_broadcast_set_affinity()
558 	if (cpumask_equal(bc->cpumask, cpumask))  in tick_broadcast_set_affinity()
561 	bc->cpumask = cpumask;  in tick_broadcast_set_affinity()
562 	irq_set_affinity(bc->irq, bc->cpumask);  in tick_broadcast_set_affinity()
594 		if (td->mode == TICKDEV_MODE_ONESHOT) {  in tick_check_oneshot_broadcast_this_cpu()
595 			clockevents_switch_state(td->evtdev,  in tick_check_oneshot_broadcast_this_cpu()
612 	dev->next_event = KTIME_MAX;  in tick_handle_oneshot_broadcast()
627 		if (td->evtdev->next_event <= now) {  in tick_handle_oneshot_broadcast()
631 			 * it can avoid reprogramming the cpu local  in tick_handle_oneshot_broadcast()
632 			 * timer in tick_broadcast_oneshot_control().  in tick_handle_oneshot_broadcast()
635 		} else if (td->evtdev->next_event < next_event) {  in tick_handle_oneshot_broadcast()
636 			next_event = td->evtdev->next_event;  in tick_handle_oneshot_broadcast()
666 	 * - The global event did not expire any CPU local  in tick_handle_oneshot_broadcast()
670 	 * - There are pending events on sleeping CPUs which were not  in tick_handle_oneshot_broadcast()
680 		td->evtdev->event_handler(td->evtdev);  in tick_handle_oneshot_broadcast()
686 	if (!(bc->features & CLOCK_EVT_FEAT_HRTIMER))  in broadcast_needs_cpu()
688 	if (bc->next_event == KTIME_MAX)  in broadcast_needs_cpu()
690 	return bc->bound_on == cpu ? -EBUSY : 0;  in broadcast_needs_cpu()
698 	 * local device if our own event is the first one to expire or  in broadcast_shutdown_local()
699 	 * if we own the broadcast timer.  in broadcast_shutdown_local()
701 	if (bc->features & CLOCK_EVT_FEAT_HRTIMER) {  in broadcast_shutdown_local()
704 		if (dev->next_event < bc->next_event)  in broadcast_shutdown_local()
721 		return -EBUSY;  in __tick_broadcast_oneshot_control()
723 	dev = this_cpu_ptr(&tick_cpu_device)->evtdev;  in __tick_broadcast_oneshot_control()
734 		 * through the EXIT path as the local timer is not  in __tick_broadcast_oneshot_control()
747 			if (bc->features & CLOCK_EVT_FEAT_HRTIMER)  in __tick_broadcast_oneshot_control()
748 				ret = -EBUSY;  in __tick_broadcast_oneshot_control()
755 			/* Conditionally shut down the local timer. */  in __tick_broadcast_oneshot_control()
759 			 * We only reprogram the broadcast timer if we  in __tick_broadcast_oneshot_control()
761 			 * if the cpu local event is earlier than the  in __tick_broadcast_oneshot_control()
769 				ret = -EBUSY;  in __tick_broadcast_oneshot_control()
770 			} else if (dev->next_event < bc->next_event) {  in __tick_broadcast_oneshot_control()
771 				tick_broadcast_set_event(bc, cpu, dev->next_event);  in __tick_broadcast_oneshot_control()
775 				 * timer to this cpu. If yes, remove  in __tick_broadcast_oneshot_control()
791 			 * timer marked this cpu in the broadcast  in __tick_broadcast_oneshot_control()
795 			 * handler. No need to reprogram the timer  in __tick_broadcast_oneshot_control()
805 			if (dev->next_event == KTIME_MAX)  in __tick_broadcast_oneshot_control()
813 			 * if the cpu local expiry time is already  in __tick_broadcast_oneshot_control()
814 			 * reached, we would reprogram the cpu local  in __tick_broadcast_oneshot_control()
815 			 * timer with an already expired event.  in __tick_broadcast_oneshot_control()
817 			 * This can lead to a ping-pong when we return  in __tick_broadcast_oneshot_control()
819 			 * timer before the cpu local timer was able  in __tick_broadcast_oneshot_control()
824 			 * enough out that the ping-pong starts.  in __tick_broadcast_oneshot_control()
826 			 * If the cpu local next_event has expired  in __tick_broadcast_oneshot_control()
827 			 * then we know that the broadcast timer  in __tick_broadcast_oneshot_control()
832 			 * will invoke the cpu local handler.  in __tick_broadcast_oneshot_control()
840 			if (dev->next_event <= now) {  in __tick_broadcast_oneshot_control()
846 			 * the cpu local timer device.  in __tick_broadcast_oneshot_control()
848 			tick_program_event(dev->next_event, 1);  in __tick_broadcast_oneshot_control()
875 		if (td->evtdev)  in tick_broadcast_init_next_event()
876 			td->evtdev->next_event = expires;  in tick_broadcast_init_next_event()
881  * tick_broadcast_setup_oneshot - setup the broadcast device
891 	if (bc->event_handler != tick_handle_oneshot_broadcast) {  in tick_broadcast_setup_oneshot()
894 		bc->event_handler = tick_handle_oneshot_broadcast;  in tick_broadcast_setup_oneshot()
913 			bc->next_event = KTIME_MAX;  in tick_broadcast_setup_oneshot()
955 		clockevents_program_event(bc, bc->next_event, 1);  in hotplug_cpu__broadcast_tick_pull()
966 	 * Clear the broadcast masks for the dead cpu, but do not stop  in tick_broadcast_oneshot_offline()
990 	return bc ? bc->features & CLOCK_EVT_FEAT_ONESHOT : false;  in tick_broadcast_oneshot_available()
998 	if (!bc || (bc->features & CLOCK_EVT_FEAT_HRTIMER))  in __tick_broadcast_oneshot_control()
999 		return -EBUSY;  in __tick_broadcast_oneshot_control()