Linux kernel mirror (for testing)
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1/* linux/include/linux/clockchips.h
2 *
3 * This file contains the structure definitions for clockchips.
4 *
5 * If you are not a clockchip, or the time of day code, you should
6 * not be including this file!
7 */
8#ifndef _LINUX_CLOCKCHIPS_H
9#define _LINUX_CLOCKCHIPS_H
10
11#ifdef CONFIG_GENERIC_CLOCKEVENTS
12
13#include <linux/clocksource.h>
14#include <linux/cpumask.h>
15#include <linux/ktime.h>
16#include <linux/notifier.h>
17
18struct clock_event_device;
19
20/* Clock event mode commands */
21enum clock_event_mode {
22 CLOCK_EVT_MODE_UNUSED = 0,
23 CLOCK_EVT_MODE_SHUTDOWN,
24 CLOCK_EVT_MODE_PERIODIC,
25 CLOCK_EVT_MODE_ONESHOT,
26};
27
28/* Clock event notification values */
29enum clock_event_nofitiers {
30 CLOCK_EVT_NOTIFY_ADD,
31 CLOCK_EVT_NOTIFY_BROADCAST_ON,
32 CLOCK_EVT_NOTIFY_BROADCAST_OFF,
33 CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
34 CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
35 CLOCK_EVT_NOTIFY_SUSPEND,
36 CLOCK_EVT_NOTIFY_RESUME,
37 CLOCK_EVT_NOTIFY_CPU_DEAD,
38};
39
40/*
41 * Clock event features
42 */
43#define CLOCK_EVT_FEAT_PERIODIC 0x000001
44#define CLOCK_EVT_FEAT_ONESHOT 0x000002
45/*
46 * x86(64) specific misfeatures:
47 *
48 * - Clockevent source stops in C3 State and needs broadcast support.
49 * - Local APIC timer is used as a dummy device.
50 */
51#define CLOCK_EVT_FEAT_C3STOP 0x000004
52#define CLOCK_EVT_FEAT_DUMMY 0x000008
53
54/**
55 * struct clock_event_device - clock event device descriptor
56 * @name: ptr to clock event name
57 * @features: features
58 * @max_delta_ns: maximum delta value in ns
59 * @min_delta_ns: minimum delta value in ns
60 * @mult: nanosecond to cycles multiplier
61 * @shift: nanoseconds to cycles divisor (power of two)
62 * @rating: variable to rate clock event devices
63 * @irq: IRQ number (only for non CPU local devices)
64 * @cpumask: cpumask to indicate for which CPUs this device works
65 * @set_next_event: set next event function
66 * @set_mode: set mode function
67 * @event_handler: Assigned by the framework to be called by the low
68 * level handler of the event source
69 * @broadcast: function to broadcast events
70 * @list: list head for the management code
71 * @mode: operating mode assigned by the management code
72 * @next_event: local storage for the next event in oneshot mode
73 */
74struct clock_event_device {
75 const char *name;
76 unsigned int features;
77 unsigned long max_delta_ns;
78 unsigned long min_delta_ns;
79 unsigned long mult;
80 int shift;
81 int rating;
82 int irq;
83 cpumask_t cpumask;
84 int (*set_next_event)(unsigned long evt,
85 struct clock_event_device *);
86 void (*set_mode)(enum clock_event_mode mode,
87 struct clock_event_device *);
88 void (*event_handler)(struct clock_event_device *);
89 void (*broadcast)(cpumask_t mask);
90 struct list_head list;
91 enum clock_event_mode mode;
92 ktime_t next_event;
93};
94
95/*
96 * Calculate a multiplication factor for scaled math, which is used to convert
97 * nanoseconds based values to clock ticks:
98 *
99 * clock_ticks = (nanoseconds * factor) >> shift.
100 *
101 * div_sc is the rearranged equation to calculate a factor from a given clock
102 * ticks / nanoseconds ratio:
103 *
104 * factor = (clock_ticks << shift) / nanoseconds
105 */
106static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
107 int shift)
108{
109 uint64_t tmp = ((uint64_t)ticks) << shift;
110
111 do_div(tmp, nsec);
112 return (unsigned long) tmp;
113}
114
115/* Clock event layer functions */
116extern unsigned long clockevent_delta2ns(unsigned long latch,
117 struct clock_event_device *evt);
118extern void clockevents_register_device(struct clock_event_device *dev);
119
120extern void clockevents_exchange_device(struct clock_event_device *old,
121 struct clock_event_device *new);
122extern
123struct clock_event_device *clockevents_request_device(unsigned int features,
124 cpumask_t cpumask);
125extern void clockevents_release_device(struct clock_event_device *dev);
126extern void clockevents_set_mode(struct clock_event_device *dev,
127 enum clock_event_mode mode);
128extern int clockevents_register_notifier(struct notifier_block *nb);
129extern void clockevents_unregister_notifier(struct notifier_block *nb);
130extern int clockevents_program_event(struct clock_event_device *dev,
131 ktime_t expires, ktime_t now);
132
133extern void clockevents_notify(unsigned long reason, void *arg);
134
135#else
136
137static inline void clockevents_resume_events(void) { }
138#define clockevents_notify(reason, arg) do { } while (0)
139
140#endif
141
142#endif