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_types.h>
16 # include <linux/ktime.h>
17 # include <linux/notifier.h>
18
19 struct clock_event_device;
20 struct 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 */
35 enum 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 */
100 struct 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 */
135 static inline bool clockevent_state_detached(struct clock_event_device *dev)
136 {
137 return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED;
138 }
139
140 static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
141 {
142 return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN;
143 }
144
145 static inline bool clockevent_state_periodic(struct clock_event_device *dev)
146 {
147 return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC;
148 }
149
150 static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
151 {
152 return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT;
153 }
154
155 static 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 */
171 static inline unsigned long
172 div_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 */
182 extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
183 extern void clockevents_register_device(struct clock_event_device *dev);
184 extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
185
186 extern void clockevents_config_and_register(struct clock_event_device *dev,
187 u32 freq, unsigned long min_delta,
188 unsigned long max_delta);
189
190 extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
191
192 static inline void
193 clockevents_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
198 extern void clockevents_suspend(void);
199 extern void clockevents_resume(void);
200
201 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
202 # ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
203 extern void tick_broadcast(const struct cpumask *mask);
204 # else
205 # define tick_broadcast NULL
206 # endif
207 extern int tick_receive_broadcast(void);
208 # endif
209
210 # if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
211 extern void tick_setup_hrtimer_broadcast(void);
212 extern int tick_check_broadcast_expired(void);
213 # else
214 static __always_inline int tick_check_broadcast_expired(void) { return 0; }
215 static inline void tick_setup_hrtimer_broadcast(void) { }
216 # endif
217
218 #else /* !CONFIG_GENERIC_CLOCKEVENTS: */
219
220 static inline void clockevents_suspend(void) { }
221 static inline void clockevents_resume(void) { }
222 static __always_inline int tick_check_broadcast_expired(void) { return 0; }
223 static inline void tick_setup_hrtimer_broadcast(void) { }
224
225 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
226
227 #endif /* _LINUX_CLOCKCHIPS_H */
228
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