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14#include <linux/cpu.h>
15#include <linux/err.h>
16#include <linux/hrtimer.h>
17#include <linux/interrupt.h>
18#include <linux/percpu.h>
19#include <linux/profile.h>
20#include <linux/sched.h>
21#include <linux/tick.h>
22
23#include "tick-internal.h"
24
25
26
27
28int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
29 int force)
30{
31 ktime_t now = ktime_get();
32 int i;
33
34 for (i = 0;;) {
35 int ret = clockevents_program_event(dev, expires, now);
36
37 if (!ret || !force)
38 return ret;
39
40
41
42
43
44
45 if (++i > 2) {
46
47 if (!dev->min_delta_ns)
48 dev->min_delta_ns = 5000;
49 else
50 dev->min_delta_ns += dev->min_delta_ns >> 1;
51
52 printk(KERN_WARNING
53 "CE: %s increasing min_delta_ns to %lu nsec\n",
54 dev->name ? dev->name : "?",
55 dev->min_delta_ns << 1);
56
57 i = 0;
58 }
59
60 now = ktime_get();
61 expires = ktime_add_ns(now, dev->min_delta_ns);
62 }
63}
64
65
66
67
68int tick_program_event(ktime_t expires, int force)
69{
70 struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
71
72 return tick_dev_program_event(dev, expires, force);
73}
74
75
76
77
78void tick_resume_oneshot(void)
79{
80 struct tick_device *td = &__get_cpu_var(tick_cpu_device);
81 struct clock_event_device *dev = td->evtdev;
82
83 clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
84 tick_program_event(ktime_get(), 1);
85}
86
87
88
89
90void tick_setup_oneshot(struct clock_event_device *newdev,
91 void (*handler)(struct clock_event_device *),
92 ktime_t next_event)
93{
94 newdev->event_handler = handler;
95 clockevents_set_mode(newdev, CLOCK_EVT_MODE_ONESHOT);
96 tick_dev_program_event(newdev, next_event, 1);
97}
98
99
100
101
102int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *))
103{
104 struct tick_device *td = &__get_cpu_var(tick_cpu_device);
105 struct clock_event_device *dev = td->evtdev;
106
107 if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) ||
108 !tick_device_is_functional(dev)) {
109
110 printk(KERN_INFO "Clockevents: "
111 "could not switch to one-shot mode:");
112 if (!dev) {
113 printk(" no tick device\n");
114 } else {
115 if (!tick_device_is_functional(dev))
116 printk(" %s is not functional.\n", dev->name);
117 else
118 printk(" %s does not support one-shot mode.\n",
119 dev->name);
120 }
121 return -EINVAL;
122 }
123
124 td->mode = TICKDEV_MODE_ONESHOT;
125 dev->event_handler = handler;
126 clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
127 tick_broadcast_switch_to_oneshot();
128 return 0;
129}
130
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134
135
136int tick_oneshot_mode_active(void)
137{
138 unsigned long flags;
139 int ret;
140
141 local_irq_save(flags);
142 ret = __get_cpu_var(tick_cpu_device).mode == TICKDEV_MODE_ONESHOT;
143 local_irq_restore(flags);
144
145 return ret;
146}
147
148#ifdef CONFIG_HIGH_RES_TIMERS
149
150
151
152
153
154int tick_init_highres(void)
155{
156 return tick_switch_to_oneshot(hrtimer_interrupt);
157}
158#endif
159