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
18 struct clock_event_device;
19
20 /* Clock event mode commands */
21 enum 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 */
30 enum 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 */
77 struct clock_event_device {
78 const char *name;
79 unsigned int features;
80 unsigned long max_delta_ns;
81 unsigned long min_delta_ns;
82 unsigned long mult;
83 int shift;
84 int rating;
85 int irq;
86 const struct cpumask *cpumask;
87 int (*set_next_event)(unsigned long evt,
88 struct clock_event_device *);
89 void (*set_mode)(enum clock_event_mode mode,
90 struct clock_event_device *);
91 void (*event_handler)(struct clock_event_device *);
92 void (*broadcast)(const struct cpumask *mask);
93 struct list_head list;
94 enum clock_event_mode mode;
95 ktime_t next_event;
96 };
97
98 /*
99 * Calculate a multiplication factor for scaled math, which is used to convert
100 * nanoseconds based values to clock ticks:
101 *
102 * clock_ticks = (nanoseconds * factor) >> shift.
103 *
104 * div_sc is the rearranged equation to calculate a factor from a given clock
105 * ticks / nanoseconds ratio:
106 *
107 * factor = (clock_ticks << shift) / nanoseconds
108 */
109 static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
110 int shift)
111 {
112 uint64_t tmp = ((uint64_t)ticks) << shift;
113
114 do_div(tmp, nsec);
115 return (unsigned long) tmp;
116 }
117
118 /* Clock event layer functions */
119 extern unsigned long clockevent_delta2ns(unsigned long latch,
120 struct clock_event_device *evt);
121 extern void clockevents_register_device(struct clock_event_device *dev);
122
123 extern void clockevents_exchange_device(struct clock_event_device *old,
124 struct clock_event_device *new);
125 extern void clockevents_set_mode(struct clock_event_device *dev,
126 enum clock_event_mode mode);
127 extern int clockevents_register_notifier(struct notifier_block *nb);
128 extern int clockevents_program_event(struct clock_event_device *dev,
129 ktime_t expires, ktime_t now);
130
131 extern void clockevents_handle_noop(struct clock_event_device *dev);
132
133 #ifdef CONFIG_GENERIC_CLOCKEVENTS
134 extern void clockevents_notify(unsigned long reason, void *arg);
135 #else
136 # define clockevents_notify(reason, arg) do { } while (0)
137 #endif
138
139 #else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */
140
141 #define clockevents_notify(reason, arg) do { } while (0)
142
143 #endif
144
145 #endif
146
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