135728b82SThomas Gleixner // SPDX-License-Identifier: GPL-2.0 2906568c9SThomas Gleixner /* 3906568c9SThomas Gleixner * This file contains the base functions to manage periodic tick 4906568c9SThomas Gleixner * related events. 5906568c9SThomas Gleixner * 6906568c9SThomas Gleixner * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> 7906568c9SThomas Gleixner * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar 8906568c9SThomas Gleixner * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner 9906568c9SThomas Gleixner */ 10906568c9SThomas Gleixner #include <linux/cpu.h> 11906568c9SThomas Gleixner #include <linux/err.h> 12906568c9SThomas Gleixner #include <linux/hrtimer.h> 13d7b90689SRussell King #include <linux/interrupt.h> 145167c506SChunyan Zhang #include <linux/nmi.h> 15906568c9SThomas Gleixner #include <linux/percpu.h> 16906568c9SThomas Gleixner #include <linux/profile.h> 17906568c9SThomas Gleixner #include <linux/sched.h> 18ccf33d68SThomas Gleixner #include <linux/module.h> 1975e0678eSRafael J. Wysocki #include <trace/events/power.h> 20906568c9SThomas Gleixner 21d7b90689SRussell King #include <asm/irq_regs.h> 22d7b90689SRussell King 23f8381cbaSThomas Gleixner #include "tick-internal.h" 24f8381cbaSThomas Gleixner 25906568c9SThomas Gleixner /* 26906568c9SThomas Gleixner * Tick devices 27906568c9SThomas Gleixner */ 28f8381cbaSThomas Gleixner DEFINE_PER_CPU(struct tick_device, tick_cpu_device); 29906568c9SThomas Gleixner /* 30906568c9SThomas Gleixner * Tick next event: keeps track of the tick time 31906568c9SThomas Gleixner */ 32f8381cbaSThomas Gleixner ktime_t tick_next_period; 33f8381cbaSThomas Gleixner ktime_t tick_period; 34050ded1bSAndrew Morton 35050ded1bSAndrew Morton /* 36050ded1bSAndrew Morton * tick_do_timer_cpu is a timer core internal variable which holds the CPU NR 37050ded1bSAndrew Morton * which is responsible for calling do_timer(), i.e. the timekeeping stuff. This 38050ded1bSAndrew Morton * variable has two functions: 39050ded1bSAndrew Morton * 40050ded1bSAndrew Morton * 1) Prevent a thundering herd issue of a gazillion of CPUs trying to grab the 41050ded1bSAndrew Morton * timekeeping lock all at once. Only the CPU which is assigned to do the 42050ded1bSAndrew Morton * update is handling it. 43050ded1bSAndrew Morton * 44050ded1bSAndrew Morton * 2) Hand off the duty in the NOHZ idle case by setting the value to 45050ded1bSAndrew Morton * TICK_DO_TIMER_NONE, i.e. a non existing CPU. So the next cpu which looks 46050ded1bSAndrew Morton * at it will take over and keep the time keeping alive. The handover 47050ded1bSAndrew Morton * procedure also covers cpu hotplug. 48050ded1bSAndrew Morton */ 496441402bSThomas Gleixner int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT; 5008ae95f4SNicholas Piggin #ifdef CONFIG_NO_HZ_FULL 5108ae95f4SNicholas Piggin /* 5208ae95f4SNicholas Piggin * tick_do_timer_boot_cpu indicates the boot CPU temporarily owns 5308ae95f4SNicholas Piggin * tick_do_timer_cpu and it should be taken over by an eligible secondary 5408ae95f4SNicholas Piggin * when one comes online. 5508ae95f4SNicholas Piggin */ 5608ae95f4SNicholas Piggin static int tick_do_timer_boot_cpu __read_mostly = -1; 5708ae95f4SNicholas Piggin #endif 58906568c9SThomas Gleixner 59289f480aSIngo Molnar /* 60289f480aSIngo Molnar * Debugging: see timer_list.c 61289f480aSIngo Molnar */ 62289f480aSIngo Molnar struct tick_device *tick_get_device(int cpu) 63289f480aSIngo Molnar { 64289f480aSIngo Molnar return &per_cpu(tick_cpu_device, cpu); 65289f480aSIngo Molnar } 66289f480aSIngo Molnar 6779bf2bb3SThomas Gleixner /** 6879bf2bb3SThomas Gleixner * tick_is_oneshot_available - check for a oneshot capable event device 6979bf2bb3SThomas Gleixner */ 7079bf2bb3SThomas Gleixner int tick_is_oneshot_available(void) 7179bf2bb3SThomas Gleixner { 72909ea964SChristoph Lameter struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); 7379bf2bb3SThomas Gleixner 743a142a06SThomas Gleixner if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT)) 753a142a06SThomas Gleixner return 0; 763a142a06SThomas Gleixner if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) 773a142a06SThomas Gleixner return 1; 783a142a06SThomas Gleixner return tick_broadcast_oneshot_available(); 7979bf2bb3SThomas Gleixner } 8079bf2bb3SThomas Gleixner 81906568c9SThomas Gleixner /* 82906568c9SThomas Gleixner * Periodic tick 83906568c9SThomas Gleixner */ 84906568c9SThomas Gleixner static void tick_periodic(int cpu) 85906568c9SThomas Gleixner { 86906568c9SThomas Gleixner if (tick_do_timer_cpu == cpu) { 87*e5d4d175SThomas Gleixner raw_spin_lock(&jiffies_lock); 88*e5d4d175SThomas Gleixner write_seqcount_begin(&jiffies_seq); 89906568c9SThomas Gleixner 90906568c9SThomas Gleixner /* Keep track of the next tick event */ 91906568c9SThomas Gleixner tick_next_period = ktime_add(tick_next_period, tick_period); 92906568c9SThomas Gleixner 93906568c9SThomas Gleixner do_timer(1); 94*e5d4d175SThomas Gleixner write_seqcount_end(&jiffies_seq); 95*e5d4d175SThomas Gleixner raw_spin_unlock(&jiffies_lock); 9647a1b796SJohn Stultz update_wall_time(); 97906568c9SThomas Gleixner } 98906568c9SThomas Gleixner 99906568c9SThomas Gleixner update_process_times(user_mode(get_irq_regs())); 100906568c9SThomas Gleixner profile_tick(CPU_PROFILING); 101906568c9SThomas Gleixner } 102906568c9SThomas Gleixner 103906568c9SThomas Gleixner /* 104906568c9SThomas Gleixner * Event handler for periodic ticks 105906568c9SThomas Gleixner */ 106906568c9SThomas Gleixner void tick_handle_periodic(struct clock_event_device *dev) 107906568c9SThomas Gleixner { 108906568c9SThomas Gleixner int cpu = smp_processor_id(); 109b97f0291SViresh Kumar ktime_t next = dev->next_event; 110906568c9SThomas Gleixner 111906568c9SThomas Gleixner tick_periodic(cpu); 112906568c9SThomas Gleixner 113c6eb3f70SThomas Gleixner #if defined(CONFIG_HIGH_RES_TIMERS) || defined(CONFIG_NO_HZ_COMMON) 114c6eb3f70SThomas Gleixner /* 115c6eb3f70SThomas Gleixner * The cpu might have transitioned to HIGHRES or NOHZ mode via 116c6eb3f70SThomas Gleixner * update_process_times() -> run_local_timers() -> 117c6eb3f70SThomas Gleixner * hrtimer_run_queues(). 118c6eb3f70SThomas Gleixner */ 119c6eb3f70SThomas Gleixner if (dev->event_handler != tick_handle_periodic) 120c6eb3f70SThomas Gleixner return; 121c6eb3f70SThomas Gleixner #endif 122c6eb3f70SThomas Gleixner 123472c4a94SViresh Kumar if (!clockevent_state_oneshot(dev)) 124906568c9SThomas Gleixner return; 125b97f0291SViresh Kumar for (;;) { 126906568c9SThomas Gleixner /* 127906568c9SThomas Gleixner * Setup the next period for devices, which do not have 128906568c9SThomas Gleixner * periodic mode: 129906568c9SThomas Gleixner */ 130b97f0291SViresh Kumar next = ktime_add(next, tick_period); 131b97f0291SViresh Kumar 132d1748302SMartin Schwidefsky if (!clockevents_program_event(dev, next, false)) 133906568c9SThomas Gleixner return; 13474a03b69Sjohn stultz /* 13574a03b69Sjohn stultz * Have to be careful here. If we're in oneshot mode, 13674a03b69Sjohn stultz * before we call tick_periodic() in a loop, we need 13774a03b69Sjohn stultz * to be sure we're using a real hardware clocksource. 13874a03b69Sjohn stultz * Otherwise we could get trapped in an infinite 13974a03b69Sjohn stultz * loop, as the tick_periodic() increments jiffies, 140cacb3c76SViresh Kumar * which then will increment time, possibly causing 14174a03b69Sjohn stultz * the loop to trigger again and again. 14274a03b69Sjohn stultz */ 14374a03b69Sjohn stultz if (timekeeping_valid_for_hres()) 144906568c9SThomas Gleixner tick_periodic(cpu); 145906568c9SThomas Gleixner } 146906568c9SThomas Gleixner } 147906568c9SThomas Gleixner 148906568c9SThomas Gleixner /* 149906568c9SThomas Gleixner * Setup the device for a periodic tick 150906568c9SThomas Gleixner */ 151f8381cbaSThomas Gleixner void tick_setup_periodic(struct clock_event_device *dev, int broadcast) 152906568c9SThomas Gleixner { 153f8381cbaSThomas Gleixner tick_set_periodic_handler(dev, broadcast); 154f8381cbaSThomas Gleixner 155f8381cbaSThomas Gleixner /* Broadcast setup ? */ 156f8381cbaSThomas Gleixner if (!tick_device_is_functional(dev)) 157f8381cbaSThomas Gleixner return; 158906568c9SThomas Gleixner 15927ce4cb4SThomas Gleixner if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) && 16027ce4cb4SThomas Gleixner !tick_broadcast_oneshot_active()) { 161d7eb231cSThomas Gleixner clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC); 162906568c9SThomas Gleixner } else { 163e1e41b6cSRasmus Villemoes unsigned int seq; 164906568c9SThomas Gleixner ktime_t next; 165906568c9SThomas Gleixner 166906568c9SThomas Gleixner do { 167*e5d4d175SThomas Gleixner seq = read_seqcount_begin(&jiffies_seq); 168906568c9SThomas Gleixner next = tick_next_period; 169*e5d4d175SThomas Gleixner } while (read_seqcount_retry(&jiffies_seq, seq)); 170906568c9SThomas Gleixner 171d7eb231cSThomas Gleixner clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); 172906568c9SThomas Gleixner 173906568c9SThomas Gleixner for (;;) { 174d1748302SMartin Schwidefsky if (!clockevents_program_event(dev, next, false)) 175906568c9SThomas Gleixner return; 176906568c9SThomas Gleixner next = ktime_add(next, tick_period); 177906568c9SThomas Gleixner } 178906568c9SThomas Gleixner } 179906568c9SThomas Gleixner } 180906568c9SThomas Gleixner 18108ae95f4SNicholas Piggin #ifdef CONFIG_NO_HZ_FULL 18208ae95f4SNicholas Piggin static void giveup_do_timer(void *info) 18308ae95f4SNicholas Piggin { 18408ae95f4SNicholas Piggin int cpu = *(unsigned int *)info; 18508ae95f4SNicholas Piggin 18608ae95f4SNicholas Piggin WARN_ON(tick_do_timer_cpu != smp_processor_id()); 18708ae95f4SNicholas Piggin 18808ae95f4SNicholas Piggin tick_do_timer_cpu = cpu; 18908ae95f4SNicholas Piggin } 19008ae95f4SNicholas Piggin 19108ae95f4SNicholas Piggin static void tick_take_do_timer_from_boot(void) 19208ae95f4SNicholas Piggin { 19308ae95f4SNicholas Piggin int cpu = smp_processor_id(); 19408ae95f4SNicholas Piggin int from = tick_do_timer_boot_cpu; 19508ae95f4SNicholas Piggin 19608ae95f4SNicholas Piggin if (from >= 0 && from != cpu) 19708ae95f4SNicholas Piggin smp_call_function_single(from, giveup_do_timer, &cpu, 1); 19808ae95f4SNicholas Piggin } 19908ae95f4SNicholas Piggin #endif 20008ae95f4SNicholas Piggin 201906568c9SThomas Gleixner /* 202906568c9SThomas Gleixner * Setup the tick device 203906568c9SThomas Gleixner */ 204906568c9SThomas Gleixner static void tick_setup_device(struct tick_device *td, 205906568c9SThomas Gleixner struct clock_event_device *newdev, int cpu, 2060de26520SRusty Russell const struct cpumask *cpumask) 207906568c9SThomas Gleixner { 208906568c9SThomas Gleixner void (*handler)(struct clock_event_device *) = NULL; 2098b0e1953SThomas Gleixner ktime_t next_event = 0; 210906568c9SThomas Gleixner 211906568c9SThomas Gleixner /* 212906568c9SThomas Gleixner * First device setup ? 213906568c9SThomas Gleixner */ 214906568c9SThomas Gleixner if (!td->evtdev) { 215906568c9SThomas Gleixner /* 216906568c9SThomas Gleixner * If no cpu took the do_timer update, assign it to 217906568c9SThomas Gleixner * this cpu: 218906568c9SThomas Gleixner */ 2196441402bSThomas Gleixner if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) { 220906568c9SThomas Gleixner tick_do_timer_cpu = cpu; 22108ae95f4SNicholas Piggin 222906568c9SThomas Gleixner tick_next_period = ktime_get(); 2238b0e1953SThomas Gleixner tick_period = NSEC_PER_SEC / HZ; 22408ae95f4SNicholas Piggin #ifdef CONFIG_NO_HZ_FULL 22508ae95f4SNicholas Piggin /* 22608ae95f4SNicholas Piggin * The boot CPU may be nohz_full, in which case set 22708ae95f4SNicholas Piggin * tick_do_timer_boot_cpu so the first housekeeping 22808ae95f4SNicholas Piggin * secondary that comes up will take do_timer from 22908ae95f4SNicholas Piggin * us. 23008ae95f4SNicholas Piggin */ 23108ae95f4SNicholas Piggin if (tick_nohz_full_cpu(cpu)) 23208ae95f4SNicholas Piggin tick_do_timer_boot_cpu = cpu; 23308ae95f4SNicholas Piggin 23408ae95f4SNicholas Piggin } else if (tick_do_timer_boot_cpu != -1 && 23508ae95f4SNicholas Piggin !tick_nohz_full_cpu(cpu)) { 23608ae95f4SNicholas Piggin tick_take_do_timer_from_boot(); 23708ae95f4SNicholas Piggin tick_do_timer_boot_cpu = -1; 23808ae95f4SNicholas Piggin WARN_ON(tick_do_timer_cpu != cpu); 23908ae95f4SNicholas Piggin #endif 240906568c9SThomas Gleixner } 241906568c9SThomas Gleixner 242906568c9SThomas Gleixner /* 243906568c9SThomas Gleixner * Startup in periodic mode first. 244906568c9SThomas Gleixner */ 245906568c9SThomas Gleixner td->mode = TICKDEV_MODE_PERIODIC; 246906568c9SThomas Gleixner } else { 247906568c9SThomas Gleixner handler = td->evtdev->event_handler; 248906568c9SThomas Gleixner next_event = td->evtdev->next_event; 2497c1e7689SVenkatesh Pallipadi td->evtdev->event_handler = clockevents_handle_noop; 250906568c9SThomas Gleixner } 251906568c9SThomas Gleixner 252906568c9SThomas Gleixner td->evtdev = newdev; 253906568c9SThomas Gleixner 254906568c9SThomas Gleixner /* 255906568c9SThomas Gleixner * When the device is not per cpu, pin the interrupt to the 256906568c9SThomas Gleixner * current cpu: 257906568c9SThomas Gleixner */ 258320ab2b0SRusty Russell if (!cpumask_equal(newdev->cpumask, cpumask)) 2590de26520SRusty Russell irq_set_affinity(newdev->irq, cpumask); 260906568c9SThomas Gleixner 261f8381cbaSThomas Gleixner /* 262f8381cbaSThomas Gleixner * When global broadcasting is active, check if the current 263f8381cbaSThomas Gleixner * device is registered as a placeholder for broadcast mode. 264f8381cbaSThomas Gleixner * This allows us to handle this x86 misfeature in a generic 26507bd1172SThomas Gleixner * way. This function also returns !=0 when we keep the 26607bd1172SThomas Gleixner * current active broadcast state for this CPU. 267f8381cbaSThomas Gleixner */ 268f8381cbaSThomas Gleixner if (tick_device_uses_broadcast(newdev, cpu)) 269f8381cbaSThomas Gleixner return; 270f8381cbaSThomas Gleixner 271906568c9SThomas Gleixner if (td->mode == TICKDEV_MODE_PERIODIC) 272906568c9SThomas Gleixner tick_setup_periodic(newdev, 0); 27379bf2bb3SThomas Gleixner else 27479bf2bb3SThomas Gleixner tick_setup_oneshot(newdev, handler, next_event); 275906568c9SThomas Gleixner } 276906568c9SThomas Gleixner 27703e13cf5SThomas Gleixner void tick_install_replacement(struct clock_event_device *newdev) 27803e13cf5SThomas Gleixner { 27922127e93SChristoph Lameter struct tick_device *td = this_cpu_ptr(&tick_cpu_device); 28003e13cf5SThomas Gleixner int cpu = smp_processor_id(); 28103e13cf5SThomas Gleixner 28203e13cf5SThomas Gleixner clockevents_exchange_device(td->evtdev, newdev); 28303e13cf5SThomas Gleixner tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); 28403e13cf5SThomas Gleixner if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) 28503e13cf5SThomas Gleixner tick_oneshot_notify(); 28603e13cf5SThomas Gleixner } 28703e13cf5SThomas Gleixner 28845cb8e01SThomas Gleixner static bool tick_check_percpu(struct clock_event_device *curdev, 28945cb8e01SThomas Gleixner struct clock_event_device *newdev, int cpu) 29045cb8e01SThomas Gleixner { 29145cb8e01SThomas Gleixner if (!cpumask_test_cpu(cpu, newdev->cpumask)) 29245cb8e01SThomas Gleixner return false; 29345cb8e01SThomas Gleixner if (cpumask_equal(newdev->cpumask, cpumask_of(cpu))) 29445cb8e01SThomas Gleixner return true; 29545cb8e01SThomas Gleixner /* Check if irq affinity can be set */ 29645cb8e01SThomas Gleixner if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq)) 29745cb8e01SThomas Gleixner return false; 29845cb8e01SThomas Gleixner /* Prefer an existing cpu local device */ 29945cb8e01SThomas Gleixner if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu))) 30045cb8e01SThomas Gleixner return false; 30145cb8e01SThomas Gleixner return true; 30245cb8e01SThomas Gleixner } 30345cb8e01SThomas Gleixner 30445cb8e01SThomas Gleixner static bool tick_check_preferred(struct clock_event_device *curdev, 30545cb8e01SThomas Gleixner struct clock_event_device *newdev) 30645cb8e01SThomas Gleixner { 30745cb8e01SThomas Gleixner /* Prefer oneshot capable device */ 30845cb8e01SThomas Gleixner if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) { 30945cb8e01SThomas Gleixner if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT)) 31045cb8e01SThomas Gleixner return false; 31145cb8e01SThomas Gleixner if (tick_oneshot_mode_active()) 31245cb8e01SThomas Gleixner return false; 31345cb8e01SThomas Gleixner } 31445cb8e01SThomas Gleixner 31570e5975dSStephen Boyd /* 31670e5975dSStephen Boyd * Use the higher rated one, but prefer a CPU local device with a lower 31770e5975dSStephen Boyd * rating than a non-CPU local device 31870e5975dSStephen Boyd */ 31970e5975dSStephen Boyd return !curdev || 32070e5975dSStephen Boyd newdev->rating > curdev->rating || 3215b5ccbc2SSudeep Holla !cpumask_equal(curdev->cpumask, newdev->cpumask); 32245cb8e01SThomas Gleixner } 32345cb8e01SThomas Gleixner 324906568c9SThomas Gleixner /* 32503e13cf5SThomas Gleixner * Check whether the new device is a better fit than curdev. curdev 32603e13cf5SThomas Gleixner * can be NULL ! 32703e13cf5SThomas Gleixner */ 32803e13cf5SThomas Gleixner bool tick_check_replacement(struct clock_event_device *curdev, 32903e13cf5SThomas Gleixner struct clock_event_device *newdev) 33003e13cf5SThomas Gleixner { 331521c4299SViresh Kumar if (!tick_check_percpu(curdev, newdev, smp_processor_id())) 33203e13cf5SThomas Gleixner return false; 33303e13cf5SThomas Gleixner 33403e13cf5SThomas Gleixner return tick_check_preferred(curdev, newdev); 33503e13cf5SThomas Gleixner } 33603e13cf5SThomas Gleixner 33703e13cf5SThomas Gleixner /* 3387126cac4SThomas Gleixner * Check, if the new registered device should be used. Called with 3397126cac4SThomas Gleixner * clockevents_lock held and interrupts disabled. 340906568c9SThomas Gleixner */ 3417172a286SThomas Gleixner void tick_check_new_device(struct clock_event_device *newdev) 342906568c9SThomas Gleixner { 343906568c9SThomas Gleixner struct clock_event_device *curdev; 344906568c9SThomas Gleixner struct tick_device *td; 3457172a286SThomas Gleixner int cpu; 346906568c9SThomas Gleixner 347906568c9SThomas Gleixner cpu = smp_processor_id(); 348906568c9SThomas Gleixner td = &per_cpu(tick_cpu_device, cpu); 349906568c9SThomas Gleixner curdev = td->evtdev; 350906568c9SThomas Gleixner 351906568c9SThomas Gleixner /* cpu local device ? */ 35245cb8e01SThomas Gleixner if (!tick_check_percpu(curdev, newdev, cpu)) 353906568c9SThomas Gleixner goto out_bc; 354906568c9SThomas Gleixner 35545cb8e01SThomas Gleixner /* Preference decision */ 35645cb8e01SThomas Gleixner if (!tick_check_preferred(curdev, newdev)) 357906568c9SThomas Gleixner goto out_bc; 358906568c9SThomas Gleixner 359ccf33d68SThomas Gleixner if (!try_module_get(newdev->owner)) 360ccf33d68SThomas Gleixner return; 361ccf33d68SThomas Gleixner 362906568c9SThomas Gleixner /* 363906568c9SThomas Gleixner * Replace the eventually existing device by the new 364f8381cbaSThomas Gleixner * device. If the current device is the broadcast device, do 365f8381cbaSThomas Gleixner * not give it back to the clockevents layer ! 366906568c9SThomas Gleixner */ 367f8381cbaSThomas Gleixner if (tick_is_broadcast_device(curdev)) { 3682344abbcSThomas Gleixner clockevents_shutdown(curdev); 369f8381cbaSThomas Gleixner curdev = NULL; 370f8381cbaSThomas Gleixner } 371906568c9SThomas Gleixner clockevents_exchange_device(curdev, newdev); 3726b954823SRusty Russell tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); 37379bf2bb3SThomas Gleixner if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) 37479bf2bb3SThomas Gleixner tick_oneshot_notify(); 3757172a286SThomas Gleixner return; 376f8381cbaSThomas Gleixner 377f8381cbaSThomas Gleixner out_bc: 378f8381cbaSThomas Gleixner /* 379f8381cbaSThomas Gleixner * Can the new device be used as a broadcast device ? 380f8381cbaSThomas Gleixner */ 3817172a286SThomas Gleixner tick_install_broadcast_device(newdev); 382906568c9SThomas Gleixner } 383906568c9SThomas Gleixner 384f32dd117SThomas Gleixner /** 385f32dd117SThomas Gleixner * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode 386f32dd117SThomas Gleixner * @state: The target state (enter/exit) 387f32dd117SThomas Gleixner * 388f32dd117SThomas Gleixner * The system enters/leaves a state, where affected devices might stop 389f32dd117SThomas Gleixner * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups. 390f32dd117SThomas Gleixner * 391f32dd117SThomas Gleixner * Called with interrupts disabled, so clockevents_lock is not 392f32dd117SThomas Gleixner * required here because the local clock event device cannot go away 393f32dd117SThomas Gleixner * under us. 394f32dd117SThomas Gleixner */ 395f32dd117SThomas Gleixner int tick_broadcast_oneshot_control(enum tick_broadcast_state state) 396f32dd117SThomas Gleixner { 397f32dd117SThomas Gleixner struct tick_device *td = this_cpu_ptr(&tick_cpu_device); 398f32dd117SThomas Gleixner 399f32dd117SThomas Gleixner if (!(td->evtdev->features & CLOCK_EVT_FEAT_C3STOP)) 400f32dd117SThomas Gleixner return 0; 401f32dd117SThomas Gleixner 402f32dd117SThomas Gleixner return __tick_broadcast_oneshot_control(state); 403f32dd117SThomas Gleixner } 4040f447051SThomas Gleixner EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control); 405f32dd117SThomas Gleixner 40652c063d1SThomas Gleixner #ifdef CONFIG_HOTPLUG_CPU 407906568c9SThomas Gleixner /* 40894df7de0SSebastien Dugue * Transfer the do_timer job away from a dying cpu. 40994df7de0SSebastien Dugue * 41052c063d1SThomas Gleixner * Called with interrupts disabled. Not locking required. If 41152c063d1SThomas Gleixner * tick_do_timer_cpu is owned by this cpu, nothing can change it. 41294df7de0SSebastien Dugue */ 41352c063d1SThomas Gleixner void tick_handover_do_timer(void) 41494df7de0SSebastien Dugue { 41552c063d1SThomas Gleixner if (tick_do_timer_cpu == smp_processor_id()) { 41694df7de0SSebastien Dugue int cpu = cpumask_first(cpu_online_mask); 41794df7de0SSebastien Dugue 41894df7de0SSebastien Dugue tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu : 41994df7de0SSebastien Dugue TICK_DO_TIMER_NONE; 42094df7de0SSebastien Dugue } 42194df7de0SSebastien Dugue } 42294df7de0SSebastien Dugue 42394df7de0SSebastien Dugue /* 424906568c9SThomas Gleixner * Shutdown an event device on a given cpu: 425906568c9SThomas Gleixner * 426906568c9SThomas Gleixner * This is called on a life CPU, when a CPU is dead. So we cannot 427906568c9SThomas Gleixner * access the hardware device itself. 428906568c9SThomas Gleixner * We just set the mode and remove it from the lists. 429906568c9SThomas Gleixner */ 430a49b116dSThomas Gleixner void tick_shutdown(unsigned int cpu) 431906568c9SThomas Gleixner { 432a49b116dSThomas Gleixner struct tick_device *td = &per_cpu(tick_cpu_device, cpu); 433906568c9SThomas Gleixner struct clock_event_device *dev = td->evtdev; 434906568c9SThomas Gleixner 435906568c9SThomas Gleixner td->mode = TICKDEV_MODE_PERIODIC; 436906568c9SThomas Gleixner if (dev) { 437906568c9SThomas Gleixner /* 438906568c9SThomas Gleixner * Prevent that the clock events layer tries to call 439906568c9SThomas Gleixner * the set mode function! 440906568c9SThomas Gleixner */ 441051ebd10SThomas Gleixner clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED); 442906568c9SThomas Gleixner clockevents_exchange_device(dev, NULL); 4436f7a05d7SThomas Gleixner dev->event_handler = clockevents_handle_noop; 444906568c9SThomas Gleixner td->evtdev = NULL; 445906568c9SThomas Gleixner } 446906568c9SThomas Gleixner } 447a49b116dSThomas Gleixner #endif 448906568c9SThomas Gleixner 4494ffee521SThomas Gleixner /** 450f46481d0SThomas Gleixner * tick_suspend_local - Suspend the local tick device 451f46481d0SThomas Gleixner * 452f46481d0SThomas Gleixner * Called from the local cpu for freeze with interrupts disabled. 453f46481d0SThomas Gleixner * 454f46481d0SThomas Gleixner * No locks required. Nothing can change the per cpu device. 455f46481d0SThomas Gleixner */ 4567270d11cSThomas Gleixner void tick_suspend_local(void) 457f46481d0SThomas Gleixner { 458f46481d0SThomas Gleixner struct tick_device *td = this_cpu_ptr(&tick_cpu_device); 459f46481d0SThomas Gleixner 460f46481d0SThomas Gleixner clockevents_shutdown(td->evtdev); 461f46481d0SThomas Gleixner } 462f46481d0SThomas Gleixner 463f46481d0SThomas Gleixner /** 464f46481d0SThomas Gleixner * tick_resume_local - Resume the local tick device 465f46481d0SThomas Gleixner * 466f46481d0SThomas Gleixner * Called from the local CPU for unfreeze or XEN resume magic. 467f46481d0SThomas Gleixner * 468f46481d0SThomas Gleixner * No locks required. Nothing can change the per cpu device. 469f46481d0SThomas Gleixner */ 470f46481d0SThomas Gleixner void tick_resume_local(void) 471f46481d0SThomas Gleixner { 472f46481d0SThomas Gleixner struct tick_device *td = this_cpu_ptr(&tick_cpu_device); 473f46481d0SThomas Gleixner bool broadcast = tick_resume_check_broadcast(); 474f46481d0SThomas Gleixner 475f46481d0SThomas Gleixner clockevents_tick_resume(td->evtdev); 476f46481d0SThomas Gleixner if (!broadcast) { 477f46481d0SThomas Gleixner if (td->mode == TICKDEV_MODE_PERIODIC) 478f46481d0SThomas Gleixner tick_setup_periodic(td->evtdev, 0); 479f46481d0SThomas Gleixner else 480f46481d0SThomas Gleixner tick_resume_oneshot(); 481f46481d0SThomas Gleixner } 482f46481d0SThomas Gleixner } 483f46481d0SThomas Gleixner 484f46481d0SThomas Gleixner /** 4854ffee521SThomas Gleixner * tick_suspend - Suspend the tick and the broadcast device 4864ffee521SThomas Gleixner * 4874ffee521SThomas Gleixner * Called from syscore_suspend() via timekeeping_suspend with only one 4884ffee521SThomas Gleixner * CPU online and interrupts disabled or from tick_unfreeze() under 4894ffee521SThomas Gleixner * tick_freeze_lock. 4904ffee521SThomas Gleixner * 4914ffee521SThomas Gleixner * No locks required. Nothing can change the per cpu device. 4924ffee521SThomas Gleixner */ 4938c53daf6SThomas Gleixner void tick_suspend(void) 4946321dd60SThomas Gleixner { 495f46481d0SThomas Gleixner tick_suspend_local(); 4964ffee521SThomas Gleixner tick_suspend_broadcast(); 4976321dd60SThomas Gleixner } 4986321dd60SThomas Gleixner 4994ffee521SThomas Gleixner /** 5004ffee521SThomas Gleixner * tick_resume - Resume the tick and the broadcast device 5014ffee521SThomas Gleixner * 5024ffee521SThomas Gleixner * Called from syscore_resume() via timekeeping_resume with only one 503f46481d0SThomas Gleixner * CPU online and interrupts disabled. 5044ffee521SThomas Gleixner * 5054ffee521SThomas Gleixner * No locks required. Nothing can change the per cpu device. 5064ffee521SThomas Gleixner */ 5078c53daf6SThomas Gleixner void tick_resume(void) 5086321dd60SThomas Gleixner { 509f46481d0SThomas Gleixner tick_resume_broadcast(); 510f46481d0SThomas Gleixner tick_resume_local(); 5116321dd60SThomas Gleixner } 5126321dd60SThomas Gleixner 51387e9b9f1SRafael J. Wysocki #ifdef CONFIG_SUSPEND 514124cf911SRafael J. Wysocki static DEFINE_RAW_SPINLOCK(tick_freeze_lock); 515124cf911SRafael J. Wysocki static unsigned int tick_freeze_depth; 516124cf911SRafael J. Wysocki 517124cf911SRafael J. Wysocki /** 518124cf911SRafael J. Wysocki * tick_freeze - Suspend the local tick and (possibly) timekeeping. 519124cf911SRafael J. Wysocki * 520124cf911SRafael J. Wysocki * Check if this is the last online CPU executing the function and if so, 521124cf911SRafael J. Wysocki * suspend timekeeping. Otherwise suspend the local tick. 522124cf911SRafael J. Wysocki * 523124cf911SRafael J. Wysocki * Call with interrupts disabled. Must be balanced with %tick_unfreeze(). 524124cf911SRafael J. Wysocki * Interrupts must not be enabled before the subsequent %tick_unfreeze(). 525124cf911SRafael J. Wysocki */ 526124cf911SRafael J. Wysocki void tick_freeze(void) 527124cf911SRafael J. Wysocki { 528124cf911SRafael J. Wysocki raw_spin_lock(&tick_freeze_lock); 529124cf911SRafael J. Wysocki 530124cf911SRafael J. Wysocki tick_freeze_depth++; 53175e0678eSRafael J. Wysocki if (tick_freeze_depth == num_online_cpus()) { 53275e0678eSRafael J. Wysocki trace_suspend_resume(TPS("timekeeping_freeze"), 53375e0678eSRafael J. Wysocki smp_processor_id(), true); 534c1a957d1SThomas Gleixner system_state = SYSTEM_SUSPEND; 5353f2552f7SChang-An Chen sched_clock_suspend(); 536124cf911SRafael J. Wysocki timekeeping_suspend(); 53775e0678eSRafael J. Wysocki } else { 538f46481d0SThomas Gleixner tick_suspend_local(); 53975e0678eSRafael J. Wysocki } 540124cf911SRafael J. Wysocki 541124cf911SRafael J. Wysocki raw_spin_unlock(&tick_freeze_lock); 542124cf911SRafael J. Wysocki } 543124cf911SRafael J. Wysocki 544124cf911SRafael J. Wysocki /** 545124cf911SRafael J. Wysocki * tick_unfreeze - Resume the local tick and (possibly) timekeeping. 546124cf911SRafael J. Wysocki * 547124cf911SRafael J. Wysocki * Check if this is the first CPU executing the function and if so, resume 548124cf911SRafael J. Wysocki * timekeeping. Otherwise resume the local tick. 549124cf911SRafael J. Wysocki * 550124cf911SRafael J. Wysocki * Call with interrupts disabled. Must be balanced with %tick_freeze(). 551124cf911SRafael J. Wysocki * Interrupts must not be enabled after the preceding %tick_freeze(). 552124cf911SRafael J. Wysocki */ 553124cf911SRafael J. Wysocki void tick_unfreeze(void) 554124cf911SRafael J. Wysocki { 555124cf911SRafael J. Wysocki raw_spin_lock(&tick_freeze_lock); 556124cf911SRafael J. Wysocki 55775e0678eSRafael J. Wysocki if (tick_freeze_depth == num_online_cpus()) { 558124cf911SRafael J. Wysocki timekeeping_resume(); 5593f2552f7SChang-An Chen sched_clock_resume(); 560c1a957d1SThomas Gleixner system_state = SYSTEM_RUNNING; 56175e0678eSRafael J. Wysocki trace_suspend_resume(TPS("timekeeping_freeze"), 56275e0678eSRafael J. Wysocki smp_processor_id(), false); 56375e0678eSRafael J. Wysocki } else { 5645167c506SChunyan Zhang touch_softlockup_watchdog(); 565422fe750SRafael J. Wysocki tick_resume_local(); 56675e0678eSRafael J. Wysocki } 567124cf911SRafael J. Wysocki 568124cf911SRafael J. Wysocki tick_freeze_depth--; 569124cf911SRafael J. Wysocki 570124cf911SRafael J. Wysocki raw_spin_unlock(&tick_freeze_lock); 571124cf911SRafael J. Wysocki } 57287e9b9f1SRafael J. Wysocki #endif /* CONFIG_SUSPEND */ 573124cf911SRafael J. Wysocki 574906568c9SThomas Gleixner /** 575906568c9SThomas Gleixner * tick_init - initialize the tick control 576906568c9SThomas Gleixner */ 577906568c9SThomas Gleixner void __init tick_init(void) 578906568c9SThomas Gleixner { 579b352bc1cSThomas Gleixner tick_broadcast_init(); 580a80e49e2SFrederic Weisbecker tick_nohz_init(); 581906568c9SThomas Gleixner } 582