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