Commit | Line | Data |
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79bf2bb3 TG |
1 | /* |
2 | * linux/kernel/time/tick-oneshot.c | |
3 | * | |
4 | * This file contains functions which manage high resolution tick | |
5 | * related events. | |
6 | * | |
7 | * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> | |
8 | * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar | |
9 | * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner | |
10 | * | |
11 | * This code is licenced under the GPL version 2. For details see | |
12 | * kernel-base/COPYING. | |
13 | */ | |
14 | #include <linux/cpu.h> | |
15 | #include <linux/err.h> | |
16 | #include <linux/hrtimer.h> | |
d7b90689 | 17 | #include <linux/interrupt.h> |
79bf2bb3 TG |
18 | #include <linux/percpu.h> |
19 | #include <linux/profile.h> | |
20 | #include <linux/sched.h> | |
79bf2bb3 TG |
21 | |
22 | #include "tick-internal.h" | |
23 | ||
7205656a TG |
24 | /** |
25 | * tick_program_event | |
26 | */ | |
27 | int tick_program_event(ktime_t expires, int force) | |
28 | { | |
909ea964 | 29 | struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); |
7205656a | 30 | |
2456e855 | 31 | if (unlikely(expires == KTIME_MAX)) { |
d2540875 VK |
32 | /* |
33 | * We don't need the clock event device any more, stop it. | |
34 | */ | |
d7eb231c | 35 | clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT_STOPPED); |
39c82caf | 36 | dev->next_event = KTIME_MAX; |
d2540875 VK |
37 | return 0; |
38 | } | |
39 | ||
472c4a94 | 40 | if (unlikely(clockevent_state_oneshot_stopped(dev))) { |
d2540875 VK |
41 | /* |
42 | * We need the clock event again, configure it in ONESHOT mode | |
43 | * before using it. | |
44 | */ | |
d7eb231c | 45 | clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); |
d2540875 VK |
46 | } |
47 | ||
d1748302 | 48 | return clockevents_program_event(dev, expires, force); |
7205656a TG |
49 | } |
50 | ||
cd05a1f8 TG |
51 | /** |
52 | * tick_resume_onshot - resume oneshot mode | |
53 | */ | |
54 | void tick_resume_oneshot(void) | |
55 | { | |
d1748302 | 56 | struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); |
cd05a1f8 | 57 | |
d7eb231c | 58 | clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); |
d1748302 | 59 | clockevents_program_event(dev, ktime_get(), true); |
cd05a1f8 TG |
60 | } |
61 | ||
79bf2bb3 TG |
62 | /** |
63 | * tick_setup_oneshot - setup the event device for oneshot mode (hres or nohz) | |
64 | */ | |
65 | void tick_setup_oneshot(struct clock_event_device *newdev, | |
66 | void (*handler)(struct clock_event_device *), | |
67 | ktime_t next_event) | |
68 | { | |
69 | newdev->event_handler = handler; | |
d7eb231c | 70 | clockevents_switch_state(newdev, CLOCK_EVT_STATE_ONESHOT); |
d1748302 | 71 | clockevents_program_event(newdev, next_event, true); |
79bf2bb3 TG |
72 | } |
73 | ||
74 | /** | |
75 | * tick_switch_to_oneshot - switch to oneshot mode | |
76 | */ | |
77 | int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *)) | |
78 | { | |
22127e93 | 79 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
79bf2bb3 TG |
80 | struct clock_event_device *dev = td->evtdev; |
81 | ||
82 | if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) || | |
820de5c3 IM |
83 | !tick_device_is_functional(dev)) { |
84 | ||
85 | printk(KERN_INFO "Clockevents: " | |
86 | "could not switch to one-shot mode:"); | |
87 | if (!dev) { | |
88 | printk(" no tick device\n"); | |
89 | } else { | |
90 | if (!tick_device_is_functional(dev)) | |
91 | printk(" %s is not functional.\n", dev->name); | |
92 | else | |
93 | printk(" %s does not support one-shot mode.\n", | |
94 | dev->name); | |
95 | } | |
79bf2bb3 | 96 | return -EINVAL; |
820de5c3 | 97 | } |
79bf2bb3 TG |
98 | |
99 | td->mode = TICKDEV_MODE_ONESHOT; | |
100 | dev->event_handler = handler; | |
d7eb231c | 101 | clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); |
79bf2bb3 TG |
102 | tick_broadcast_switch_to_oneshot(); |
103 | return 0; | |
104 | } | |
105 | ||
cd6d95d8 TG |
106 | /** |
107 | * tick_check_oneshot_mode - check whether the system is in oneshot mode | |
108 | * | |
109 | * returns 1 when either nohz or highres are enabled. otherwise 0. | |
110 | */ | |
111 | int tick_oneshot_mode_active(void) | |
112 | { | |
113 | unsigned long flags; | |
114 | int ret; | |
115 | ||
116 | local_irq_save(flags); | |
909ea964 | 117 | ret = __this_cpu_read(tick_cpu_device.mode) == TICKDEV_MODE_ONESHOT; |
cd6d95d8 TG |
118 | local_irq_restore(flags); |
119 | ||
120 | return ret; | |
121 | } | |
122 | ||
79bf2bb3 TG |
123 | #ifdef CONFIG_HIGH_RES_TIMERS |
124 | /** | |
125 | * tick_init_highres - switch to high resolution mode | |
126 | * | |
127 | * Called with interrupts disabled. | |
128 | */ | |
129 | int tick_init_highres(void) | |
130 | { | |
131 | return tick_switch_to_oneshot(hrtimer_interrupt); | |
132 | } | |
133 | #endif |