1/* SPDX-License-Identifier: GPL-2.0 */
2/*  linux/include/linux/clockchips.h
3 *
4 *  This file contains the structure definitions for clockchips.
5 *
6 *  If you are not a clockchip, or the time of day code, you should
7 *  not be including this file!
8 */
9#ifndef _LINUX_CLOCKCHIPS_H
10#define _LINUX_CLOCKCHIPS_H
11
12#ifdef CONFIG_GENERIC_CLOCKEVENTS
13
14# include <linux/clocksource.h>
15# include <linux/cpumask.h>
16# include <linux/ktime.h>
17# include <linux/notifier.h>
18
19struct clock_event_device;
20struct module;
21
22/*
23 * Possible states of a clock event device.
24 *
25 * DETACHED:	Device is not used by clockevents core. Initial state or can be
26 *		reached from SHUTDOWN.
27 * SHUTDOWN:	Device is powered-off. Can be reached from PERIODIC or ONESHOT.
28 * PERIODIC:	Device is programmed to generate events periodically. Can be
29 *		reached from DETACHED or SHUTDOWN.
30 * ONESHOT:	Device is programmed to generate event only once. Can be reached
31 *		from DETACHED or SHUTDOWN.
32 * ONESHOT_STOPPED: Device was programmed in ONESHOT mode and is temporarily
33 *		    stopped.
34 */
35enum clock_event_state {
36	CLOCK_EVT_STATE_DETACHED,
37	CLOCK_EVT_STATE_SHUTDOWN,
38	CLOCK_EVT_STATE_PERIODIC,
39	CLOCK_EVT_STATE_ONESHOT,
40	CLOCK_EVT_STATE_ONESHOT_STOPPED,
41};
42
43/*
44 * Clock event features
45 */
46# define CLOCK_EVT_FEAT_PERIODIC	0x000001
47# define CLOCK_EVT_FEAT_ONESHOT		0x000002
48# define CLOCK_EVT_FEAT_KTIME		0x000004
49
50/*
51 * x86(64) specific (mis)features:
52 *
53 * - Clockevent source stops in C3 State and needs broadcast support.
54 * - Local APIC timer is used as a dummy device.
55 */
56# define CLOCK_EVT_FEAT_C3STOP		0x000008
57# define CLOCK_EVT_FEAT_DUMMY		0x000010
58
59/*
60 * Core shall set the interrupt affinity dynamically in broadcast mode
61 */
62# define CLOCK_EVT_FEAT_DYNIRQ		0x000020
63# define CLOCK_EVT_FEAT_PERCPU		0x000040
64
65/*
66 * Clockevent device is based on a hrtimer for broadcast
67 */
68# define CLOCK_EVT_FEAT_HRTIMER		0x000080
69
70/**
71 * struct clock_event_device - clock event device descriptor
72 * @event_handler:	Assigned by the framework to be called by the low
73 *			level handler of the event source
74 * @set_next_event:	set next event function using a clocksource delta
75 * @set_next_ktime:	set next event function using a direct ktime value
76 * @next_event:		local storage for the next event in oneshot mode
77 * @max_delta_ns:	maximum delta value in ns
78 * @min_delta_ns:	minimum delta value in ns
79 * @mult:		nanosecond to cycles multiplier
80 * @shift:		nanoseconds to cycles divisor (power of two)
81 * @state_use_accessors:current state of the device, assigned by the core code
82 * @features:		features
83 * @retries:		number of forced programming retries
84 * @set_state_periodic:	switch state to periodic
85 * @set_state_oneshot:	switch state to oneshot
86 * @set_state_oneshot_stopped: switch state to oneshot_stopped
87 * @set_state_shutdown:	switch state to shutdown
88 * @tick_resume:	resume clkevt device
89 * @broadcast:		function to broadcast events
90 * @min_delta_ticks:	minimum delta value in ticks stored for reconfiguration
91 * @max_delta_ticks:	maximum delta value in ticks stored for reconfiguration
92 * @name:		ptr to clock event name
93 * @rating:		variable to rate clock event devices
94 * @irq:		IRQ number (only for non CPU local devices)
95 * @bound_on:		Bound on CPU
96 * @cpumask:		cpumask to indicate for which CPUs this device works
97 * @list:		list head for the management code
98 * @owner:		module reference
99 */
100struct clock_event_device {
101	void			(*event_handler)(struct clock_event_device *);
102	int			(*set_next_event)(unsigned long evt, struct clock_event_device *);
103	int			(*set_next_ktime)(ktime_t expires, struct clock_event_device *);
104	ktime_t			next_event;
105	u64			max_delta_ns;
106	u64			min_delta_ns;
107	u32			mult;
108	u32			shift;
109	enum clock_event_state	state_use_accessors;
110	unsigned int		features;
111	unsigned long		retries;
112
113	int			(*set_state_periodic)(struct clock_event_device *);
114	int			(*set_state_oneshot)(struct clock_event_device *);
115	int			(*set_state_oneshot_stopped)(struct clock_event_device *);
116	int			(*set_state_shutdown)(struct clock_event_device *);
117	int			(*tick_resume)(struct clock_event_device *);
118
119	void			(*broadcast)(const struct cpumask *mask);
120	void			(*suspend)(struct clock_event_device *);
121	void			(*resume)(struct clock_event_device *);
122	unsigned long		min_delta_ticks;
123	unsigned long		max_delta_ticks;
124
125	const char		*name;
126	int			rating;
127	int			irq;
128	int			bound_on;
129	const struct cpumask	*cpumask;
130	struct list_head	list;
131	struct module		*owner;
132} ____cacheline_aligned;
133
134/* Helpers to verify state of a clockevent device */
135static inline bool clockevent_state_detached(struct clock_event_device *dev)
136{
137	return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED;
138}
139
140static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
141{
142	return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN;
143}
144
145static inline bool clockevent_state_periodic(struct clock_event_device *dev)
146{
147	return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC;
148}
149
150static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
151{
152	return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT;
153}
154
155static inline bool clockevent_state_oneshot_stopped(struct clock_event_device *dev)
156{
157	return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT_STOPPED;
158}
159
160/*
161 * Calculate a multiplication factor for scaled math, which is used to convert
162 * nanoseconds based values to clock ticks:
163 *
164 * clock_ticks = (nanoseconds * factor) >> shift.
165 *
166 * div_sc is the rearranged equation to calculate a factor from a given clock
167 * ticks / nanoseconds ratio:
168 *
169 * factor = (clock_ticks << shift) / nanoseconds
170 */
171static inline unsigned long
172div_sc(unsigned long ticks, unsigned long nsec, int shift)
173{
174	u64 tmp = ((u64)ticks) << shift;
175
176	do_div(tmp, nsec);
177
178	return (unsigned long) tmp;
179}
180
181/* Clock event layer functions */
182extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
183extern void clockevents_register_device(struct clock_event_device *dev);
184extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
185
186extern void clockevents_config_and_register(struct clock_event_device *dev,
187					    u32 freq, unsigned long min_delta,
188					    unsigned long max_delta);
189
190extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
191
192static inline void
193clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 maxsec)
194{
195	return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, maxsec);
196}
197
198extern void clockevents_suspend(void);
199extern void clockevents_resume(void);
200
201# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
202#  ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
203extern void tick_broadcast(const struct cpumask *mask);
204#  else
205#   define tick_broadcast	NULL
206#  endif
207extern int tick_receive_broadcast(void);
208# endif
209
210# if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
211extern void tick_setup_hrtimer_broadcast(void);
212extern int tick_check_broadcast_expired(void);
213# else
214static __always_inline int tick_check_broadcast_expired(void) { return 0; }
215static inline void tick_setup_hrtimer_broadcast(void) { }
216# endif
217
218#else /* !CONFIG_GENERIC_CLOCKEVENTS: */
219
220static inline void clockevents_suspend(void) { }
221static inline void clockevents_resume(void) { }
222static __always_inline int tick_check_broadcast_expired(void) { return 0; }
223static inline void tick_setup_hrtimer_broadcast(void) { }
224
225#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
226
227#endif /* _LINUX_CLOCKCHIPS_H */
228