aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/clockchips.h
blob: 66346521cb6561641045297cb74c8d15f7b71f74 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
/*  linux/include/linux/clockchips.h
 *
 *  This file contains the structure definitions for clockchips.
 *
 *  If you are not a clockchip, or the time of day code, you should
 *  not be including this file!
 */
#ifndef _LINUX_CLOCKCHIPS_H
#define _LINUX_CLOCKCHIPS_H

#ifdef CONFIG_GENERIC_CLOCKEVENTS_BUILD

#include <linux/clocksource.h>
#include <linux/cpumask.h>
#include <linux/ktime.h>
#include <linux/notifier.h>

struct clock_event_device;

/* Clock event mode commands */
enum clock_event_mode {
	CLOCK_EVT_MODE_UNUSED = 0,
	CLOCK_EVT_MODE_SHUTDOWN,
	CLOCK_EVT_MODE_PERIODIC,
	CLOCK_EVT_MODE_ONESHOT,
	CLOCK_EVT_MODE_RESUME,
};

/* Clock event notification values */
enum clock_event_nofitiers {
	CLOCK_EVT_NOTIFY_ADD,
	CLOCK_EVT_NOTIFY_BROADCAST_ON,
	CLOCK_EVT_NOTIFY_BROADCAST_OFF,
	CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
	CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
	CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
	CLOCK_EVT_NOTIFY_SUSPEND,
	CLOCK_EVT_NOTIFY_RESUME,
	CLOCK_EVT_NOTIFY_CPU_DYING,
	CLOCK_EVT_NOTIFY_CPU_DEAD,
};

/*
 * Clock event features
 */
#define CLOCK_EVT_FEAT_PERIODIC		0x000001
#define CLOCK_EVT_FEAT_ONESHOT		0x000002
#define CLOCK_EVT_FEAT_KTIME		0x000004
/*
 * x86(64) specific misfeatures:
 *
 * - Clockevent source stops in C3 State and needs broadcast support.
 * - Local APIC timer is used as a dummy device.
 */
#define CLOCK_EVT_FEAT_C3STOP		0x000008
#define CLOCK_EVT_FEAT_DUMMY		0x000010

/**
 * struct clock_event_device - clock event device descriptor
 * @event_handler:	Assigned by the framework to be called by the low
 *			level handler of the event source
 * @set_next_event:	set next event function using a clocksource delta
 * @set_next_ktime:	set next event function using a direct ktime value
 * @next_event:		local storage for the next event in oneshot mode
 * @max_delta_ns:	maximum delta value in ns
 * @min_delta_ns:	minimum delta value in ns
 * @mult:		nanosecond to cycles multiplier
 * @shift:		nanoseconds to cycles divisor (power of two)
 * @mode:		operating mode assigned by the management code
 * @features:		features
 * @retries:		number of forced programming retries
 * @set_mode:		set mode function
 * @broadcast:		function to broadcast events
 * @min_delta_ticks:	minimum delta value in ticks stored for reconfiguration
 * @max_delta_ticks:	maximum delta value in ticks stored for reconfiguration
 * @name:		ptr to clock event name
 * @rating:		variable to rate clock event devices
 * @irq:		IRQ number (only for non CPU local devices)
 * @cpumask:		cpumask to indicate for which CPUs this device works
 * @list:		list head for the management code
 */
struct clock_event_device {
	void			(*event_handler)(struct clock_event_device *);
	int			(*set_next_event)(unsigned long evt,
						  struct clock_event_device *);
	int			(*set_next_ktime)(ktime_t expires,
						  struct clock_event_device *);
	ktime_t			next_event;
	u64			max_delta_ns;
	u64			min_delta_ns;
	u32			mult;
	u32			shift;
	enum clock_event_mode	mode;
	unsigned int		features;
	unsigned long		retries;

	void			(*broadcast)(const struct cpumask *mask);
	void			(*set_mode)(enum clock_event_mode mode,
					    struct clock_event_device *);
	void			(*suspend)(struct clock_event_device *);
	void			(*resume)(struct clock_event_device *);
	unsigned long		min_delta_ticks;
	unsigned long		max_delta_ticks;

	const char		*name;
	int			rating;
	int			irq;
	const struct cpumask	*cpumask;
	struct list_head	list;
} ____cacheline_aligned;

/*
 * Calculate a multiplication factor for scaled math, which is used to convert
 * nanoseconds based values to clock ticks:
 *
 * clock_ticks = (nanoseconds * factor) >> shift.
 *
 * div_sc is the rearranged equation to calculate a factor from a given clock
 * ticks / nanoseconds ratio:
 *
 * factor = (clock_ticks << shift) / nanoseconds
 */
static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
				   int shift)
{
	uint64_t tmp = ((uint64_t)ticks) << shift;

	do_div(tmp, nsec);
	return (unsigned long) tmp;
}

/* Clock event layer functions */
extern u64 clockevent_delta2ns(unsigned long latch,
			       struct clock_event_device *evt);
extern void clockevents_register_device(struct clock_event_device *dev);

extern void clockevents_config(struct clock_event_device *dev, u32 freq);
extern void clockevents_config_and_register(struct clock_event_device *dev,
					    u32 freq, unsigned long min_delta,
					    unsigned long max_delta);

extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);

extern void clockevents_exchange_device(struct clock_event_device *old,
					struct clock_event_device *new);
extern void clockevents_set_mode(struct clock_event_device *dev,
				 enum clock_event_mode mode);
extern int clockevents_register_notifier(struct notifier_block *nb);
extern int clockevents_program_event(struct clock_event_device *dev,
				     ktime_t expires, bool force);

extern void clockevents_handle_noop(struct clock_event_device *dev);

static inline void
clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
{
	return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC,
				      freq, minsec);
}

extern void clockevents_suspend(void);
extern void clockevents_resume(void);

#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
#ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
extern void tick_broadcast(const struct cpumask *mask);
#else
#define tick_broadcast	NULL
#endif
extern int tick_receive_broadcast(void);
#endif

#ifdef CONFIG_GENERIC_CLOCKEVENTS
extern void clockevents_notify(unsigned long reason, void *arg);
#else
# define clockevents_notify(reason, arg) do { } while (0)
#endif

#else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */

static inline void clockevents_suspend(void) {}
static inline void clockevents_resume(void) {}

#define clockevents_notify(reason, arg) do { } while (0)

#endif

#endif