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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /kernel/time/tick-oneshot.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | kernel/time/tick-oneshot.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c new file mode 100644 index 000000000..475ecceda --- /dev/null +++ b/kernel/time/tick-oneshot.c @@ -0,0 +1,128 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains functions which manage high resolution tick + * related events. + * + * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> + * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar + * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner + */ +#include <linux/cpu.h> +#include <linux/err.h> +#include <linux/hrtimer.h> +#include <linux/interrupt.h> +#include <linux/percpu.h> +#include <linux/profile.h> +#include <linux/sched.h> + +#include "tick-internal.h" + +/** + * tick_program_event + */ +int tick_program_event(ktime_t expires, int force) +{ + struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); + + if (unlikely(expires == KTIME_MAX)) { + /* + * We don't need the clock event device any more, stop it. + */ + clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT_STOPPED); + dev->next_event = KTIME_MAX; + return 0; + } + + if (unlikely(clockevent_state_oneshot_stopped(dev))) { + /* + * We need the clock event again, configure it in ONESHOT mode + * before using it. + */ + clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); + } + + return clockevents_program_event(dev, expires, force); +} + +/** + * tick_resume_oneshot - resume oneshot mode + */ +void tick_resume_oneshot(void) +{ + struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); + + clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); + clockevents_program_event(dev, ktime_get(), true); +} + +/** + * tick_setup_oneshot - setup the event device for oneshot mode (hres or nohz) + */ +void tick_setup_oneshot(struct clock_event_device *newdev, + void (*handler)(struct clock_event_device *), + ktime_t next_event) +{ + newdev->event_handler = handler; + clockevents_switch_state(newdev, CLOCK_EVT_STATE_ONESHOT); + clockevents_program_event(newdev, next_event, true); +} + +/** + * tick_switch_to_oneshot - switch to oneshot mode + */ +int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *)) +{ + struct tick_device *td = this_cpu_ptr(&tick_cpu_device); + struct clock_event_device *dev = td->evtdev; + + if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) || + !tick_device_is_functional(dev)) { + + pr_info("Clockevents: could not switch to one-shot mode:"); + if (!dev) { + pr_cont(" no tick device\n"); + } else { + if (!tick_device_is_functional(dev)) + pr_cont(" %s is not functional.\n", dev->name); + else + pr_cont(" %s does not support one-shot mode.\n", + dev->name); + } + return -EINVAL; + } + + td->mode = TICKDEV_MODE_ONESHOT; + dev->event_handler = handler; + clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); + tick_broadcast_switch_to_oneshot(); + return 0; +} + +/** + * tick_check_oneshot_mode - check whether the system is in oneshot mode + * + * returns 1 when either nohz or highres are enabled. otherwise 0. + */ +int tick_oneshot_mode_active(void) +{ + unsigned long flags; + int ret; + + local_irq_save(flags); + ret = __this_cpu_read(tick_cpu_device.mode) == TICKDEV_MODE_ONESHOT; + local_irq_restore(flags); + + return ret; +} + +#ifdef CONFIG_HIGH_RES_TIMERS +/** + * tick_init_highres - switch to high resolution mode + * + * Called with interrupts disabled. + */ +int tick_init_highres(void) +{ + return tick_switch_to_oneshot(hrtimer_interrupt); +} +#endif |