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;
19struct module;
20
21/* Clock event mode commands for legacy ->set_mode(): OBSOLETE */
22enum clock_event_mode {
23	CLOCK_EVT_MODE_UNUSED,
24	CLOCK_EVT_MODE_SHUTDOWN,
25	CLOCK_EVT_MODE_PERIODIC,
26	CLOCK_EVT_MODE_ONESHOT,
27	CLOCK_EVT_MODE_RESUME,
28};
29
30/*
31 * Possible states of a clock event device.
32 *
33 * DETACHED:	Device is not used by clockevents core. Initial state or can be
34 *		reached from SHUTDOWN.
35 * SHUTDOWN:	Device is powered-off. Can be reached from PERIODIC or ONESHOT.
36 * PERIODIC:	Device is programmed to generate events periodically. Can be
37 *		reached from DETACHED or SHUTDOWN.
38 * ONESHOT:	Device is programmed to generate event only once. Can be reached
39 *		from DETACHED or SHUTDOWN.
40 */
41enum clock_event_state {
42	CLOCK_EVT_STATE_DETACHED,
43	CLOCK_EVT_STATE_SHUTDOWN,
44	CLOCK_EVT_STATE_PERIODIC,
45	CLOCK_EVT_STATE_ONESHOT,
46};
47
48/*
49 * Clock event features
50 */
51# define CLOCK_EVT_FEAT_PERIODIC	0x000001
52# define CLOCK_EVT_FEAT_ONESHOT		0x000002
53# define CLOCK_EVT_FEAT_KTIME		0x000004
54
55/*
56 * x86(64) specific (mis)features:
57 *
58 * - Clockevent source stops in C3 State and needs broadcast support.
59 * - Local APIC timer is used as a dummy device.
60 */
61# define CLOCK_EVT_FEAT_C3STOP		0x000008
62# define CLOCK_EVT_FEAT_DUMMY		0x000010
63
64/*
65 * Core shall set the interrupt affinity dynamically in broadcast mode
66 */
67# define CLOCK_EVT_FEAT_DYNIRQ		0x000020
68# define CLOCK_EVT_FEAT_PERCPU		0x000040
69
70/*
71 * Clockevent device is based on a hrtimer for broadcast
72 */
73# define CLOCK_EVT_FEAT_HRTIMER		0x000080
74
75/**
76 * struct clock_event_device - clock event device descriptor
77 * @event_handler:	Assigned by the framework to be called by the low
78 *			level handler of the event source
79 * @set_next_event:	set next event function using a clocksource delta
80 * @set_next_ktime:	set next event function using a direct ktime value
81 * @next_event:		local storage for the next event in oneshot mode
82 * @max_delta_ns:	maximum delta value in ns
83 * @min_delta_ns:	minimum delta value in ns
84 * @mult:		nanosecond to cycles multiplier
85 * @shift:		nanoseconds to cycles divisor (power of two)
86 * @mode:		operating mode, relevant only to ->set_mode(), OBSOLETE
87 * @state:		current state of the device, assigned by the core code
88 * @features:		features
89 * @retries:		number of forced programming retries
90 * @set_mode:		legacy set mode function, only for modes <= CLOCK_EVT_MODE_RESUME.
91 * @set_state_periodic:	switch state to periodic, if !set_mode
92 * @set_state_oneshot:	switch state to oneshot, if !set_mode
93 * @set_state_shutdown:	switch state to shutdown, if !set_mode
94 * @tick_resume:	resume clkevt device, if !set_mode
95 * @broadcast:		function to broadcast events
96 * @min_delta_ticks:	minimum delta value in ticks stored for reconfiguration
97 * @max_delta_ticks:	maximum delta value in ticks stored for reconfiguration
98 * @name:		ptr to clock event name
99 * @rating:		variable to rate clock event devices
100 * @irq:		IRQ number (only for non CPU local devices)
101 * @bound_on:		Bound on CPU
102 * @cpumask:		cpumask to indicate for which CPUs this device works
103 * @list:		list head for the management code
104 * @owner:		module reference
105 */
106struct clock_event_device {
107	void			(*event_handler)(struct clock_event_device *);
108	int			(*set_next_event)(unsigned long evt, struct clock_event_device *);
109	int			(*set_next_ktime)(ktime_t expires, struct clock_event_device *);
110	ktime_t			next_event;
111	u64			max_delta_ns;
112	u64			min_delta_ns;
113	u32			mult;
114	u32			shift;
115	enum clock_event_mode	mode;
116	enum clock_event_state	state;
117	unsigned int		features;
118	unsigned long		retries;
119
120	/*
121	 * State transition callback(s): Only one of the two groups should be
122	 * defined:
123	 * - set_mode(), only for modes <= CLOCK_EVT_MODE_RESUME.
124	 * - set_state_{shutdown|periodic|oneshot}(), tick_resume().
125	 */
126	void			(*set_mode)(enum clock_event_mode mode, struct clock_event_device *);
127	int			(*set_state_periodic)(struct clock_event_device *);
128	int			(*set_state_oneshot)(struct clock_event_device *);
129	int			(*set_state_shutdown)(struct clock_event_device *);
130	int			(*tick_resume)(struct clock_event_device *);
131
132	void			(*broadcast)(const struct cpumask *mask);
133	void			(*suspend)(struct clock_event_device *);
134	void			(*resume)(struct clock_event_device *);
135	unsigned long		min_delta_ticks;
136	unsigned long		max_delta_ticks;
137
138	const char		*name;
139	int			rating;
140	int			irq;
141	int			bound_on;
142	const struct cpumask	*cpumask;
143	struct list_head	list;
144	struct module		*owner;
145} ____cacheline_aligned;
146
147/*
148 * Calculate a multiplication factor for scaled math, which is used to convert
149 * nanoseconds based values to clock ticks:
150 *
151 * clock_ticks = (nanoseconds * factor) >> shift.
152 *
153 * div_sc is the rearranged equation to calculate a factor from a given clock
154 * ticks / nanoseconds ratio:
155 *
156 * factor = (clock_ticks << shift) / nanoseconds
157 */
158static inline unsigned long
159div_sc(unsigned long ticks, unsigned long nsec, int shift)
160{
161	u64 tmp = ((u64)ticks) << shift;
162
163	do_div(tmp, nsec);
164
165	return (unsigned long) tmp;
166}
167
168/* Clock event layer functions */
169extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
170extern void clockevents_register_device(struct clock_event_device *dev);
171extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
172
173extern void clockevents_config(struct clock_event_device *dev, u32 freq);
174extern void clockevents_config_and_register(struct clock_event_device *dev,
175					    u32 freq, unsigned long min_delta,
176					    unsigned long max_delta);
177
178extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
179
180static inline void
181clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
182{
183	return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, minsec);
184}
185
186extern void clockevents_suspend(void);
187extern void clockevents_resume(void);
188
189# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
190#  ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
191extern void tick_broadcast(const struct cpumask *mask);
192#  else
193#   define tick_broadcast	NULL
194#  endif
195extern int tick_receive_broadcast(void);
196# endif
197
198# if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
199extern void tick_setup_hrtimer_broadcast(void);
200extern int tick_check_broadcast_expired(void);
201# else
202static inline int tick_check_broadcast_expired(void) { return 0; }
203static inline void tick_setup_hrtimer_broadcast(void) { }
204# endif
205
206extern int clockevents_notify(unsigned long reason, void *arg);
207
208#else /* !CONFIG_GENERIC_CLOCKEVENTS: */
209
210static inline void clockevents_suspend(void) { }
211static inline void clockevents_resume(void) { }
212static inline int clockevents_notify(unsigned long reason, void *arg) { return 0; }
213static inline int tick_check_broadcast_expired(void) { return 0; }
214static inline void tick_setup_hrtimer_broadcast(void) { }
215
216#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
217
218#endif /* _LINUX_CLOCKCHIPS_H */
219