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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_BUILD
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 CLOCK_EVT_MODE_RESUME,
27};
28
29/* Clock event notification values */
30enum clock_event_nofitiers {
31 CLOCK_EVT_NOTIFY_ADD,
32 CLOCK_EVT_NOTIFY_BROADCAST_ON,
33 CLOCK_EVT_NOTIFY_BROADCAST_OFF,
34 CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
35 CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
36 CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
37 CLOCK_EVT_NOTIFY_SUSPEND,
38 CLOCK_EVT_NOTIFY_RESUME,
39 CLOCK_EVT_NOTIFY_CPU_DYING,
40 CLOCK_EVT_NOTIFY_CPU_DEAD,
41};
42
43/*
44 * Clock event features
45 */
46#define CLOCK_EVT_FEAT_PERIODIC 0x000001
47#define CLOCK_EVT_FEAT_ONESHOT 0x000002
48/*
49 * x86(64) specific misfeatures:
50 *
51 * - Clockevent source stops in C3 State and needs broadcast support.
52 * - Local APIC timer is used as a dummy device.
53 */
54#define CLOCK_EVT_FEAT_C3STOP 0x000004
55#define CLOCK_EVT_FEAT_DUMMY 0x000008
56
57/**
58 * struct clock_event_device - clock event device descriptor
59 * @name: ptr to clock event name
60 * @features: features
61 * @max_delta_ns: maximum delta value in ns
62 * @min_delta_ns: minimum delta value in ns
63 * @mult: nanosecond to cycles multiplier
64 * @shift: nanoseconds to cycles divisor (power of two)
65 * @rating: variable to rate clock event devices
66 * @irq: IRQ number (only for non CPU local devices)
67 * @cpumask: cpumask to indicate for which CPUs this device works
68 * @set_next_event: set next event function
69 * @set_mode: set mode function
70 * @event_handler: Assigned by the framework to be called by the low
71 * level handler of the event source
72 * @broadcast: function to broadcast events
73 * @list: list head for the management code
74 * @mode: operating mode assigned by the management code
75 * @next_event: local storage for the next event in oneshot mode
76 * @retries: number of forced programming retries
77 */
78struct clock_event_device {
79 const char *name;
80 unsigned int features;
81 u64 max_delta_ns;
82 u64 min_delta_ns;
83 u32 mult;
84 u32 shift;
85 int rating;
86 int irq;
87 const struct cpumask *cpumask;
88 int (*set_next_event)(unsigned long evt,
89 struct clock_event_device *);
90 void (*set_mode)(enum clock_event_mode mode,
91 struct clock_event_device *);
92 void (*event_handler)(struct clock_event_device *);
93 void (*broadcast)(const struct cpumask *mask);
94 struct list_head list;
95 enum clock_event_mode mode;
96 ktime_t next_event;
97 unsigned long retries;
98};
99
100/*
101 * Calculate a multiplication factor for scaled math, which is used to convert
102 * nanoseconds based values to clock ticks:
103 *
104 * clock_ticks = (nanoseconds * factor) >> shift.
105 *
106 * div_sc is the rearranged equation to calculate a factor from a given clock
107 * ticks / nanoseconds ratio:
108 *
109 * factor = (clock_ticks << shift) / nanoseconds
110 */
111static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
112 int shift)
113{
114 uint64_t tmp = ((uint64_t)ticks) << shift;
115
116 do_div(tmp, nsec);
117 return (unsigned long) tmp;
118}
119
120/* Clock event layer functions */
121extern u64 clockevent_delta2ns(unsigned long latch,
122 struct clock_event_device *evt);
123extern void clockevents_register_device(struct clock_event_device *dev);
124
125extern void clockevents_exchange_device(struct clock_event_device *old,
126 struct clock_event_device *new);
127extern void clockevents_set_mode(struct clock_event_device *dev,
128 enum clock_event_mode mode);
129extern int clockevents_register_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_handle_noop(struct clock_event_device *dev);
134
135static inline void
136clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
137{
138 return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC,
139 freq, minsec);
140}
141
142#ifdef CONFIG_GENERIC_CLOCKEVENTS
143extern void clockevents_notify(unsigned long reason, void *arg);
144#else
145# define clockevents_notify(reason, arg) do { } while (0)
146#endif
147
148#else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */
149
150#define clockevents_notify(reason, arg) do { } while (0)
151
152#endif
153
154#endif