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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
734efb46 JS |
2 | /* linux/include/linux/clocksource.h |
3 | * | |
4 | * This file contains the structure definitions for clocksources. | |
5 | * | |
6 | * If you are not a clocksource, or timekeeping code, you should | |
7 | * not be including this file! | |
8 | */ | |
9 | #ifndef _LINUX_CLOCKSOURCE_H | |
10 | #define _LINUX_CLOCKSOURCE_H | |
11 | ||
12 | #include <linux/types.h> | |
13 | #include <linux/timex.h> | |
14 | #include <linux/time.h> | |
15 | #include <linux/list.h> | |
329c8d84 | 16 | #include <linux/cache.h> |
5d8b34fd | 17 | #include <linux/timer.h> |
f1b82746 | 18 | #include <linux/init.h> |
02fad5e9 | 19 | #include <linux/of.h> |
734efb46 JS |
20 | #include <asm/div64.h> |
21 | #include <asm/io.h> | |
22 | ||
5d8b34fd | 23 | struct clocksource; |
09ac369c | 24 | struct module; |
734efb46 | 25 | |
ae7bd11b | 26 | #ifdef CONFIG_ARCH_CLOCKSOURCE_DATA |
433bd805 | 27 | #include <asm/clocksource.h> |
ae7bd11b | 28 | #endif |
433bd805 | 29 | |
734efb46 JS |
30 | /** |
31 | * struct clocksource - hardware abstraction for a free running counter | |
32 | * Provides mostly state-free accessors to the underlying hardware. | |
a038a353 | 33 | * This is the structure used for system time. |
734efb46 JS |
34 | * |
35 | * @name: ptr to clocksource name | |
36 | * @list: list head for registration | |
37 | * @rating: rating value for selection (higher is better) | |
38 | * To avoid rating inflation the following | |
39 | * list should give you a guide as to how | |
40 | * to assign your clocksource a rating | |
41 | * 1-99: Unfit for real use | |
42 | * Only available for bootup and testing purposes. | |
43 | * 100-199: Base level usability. | |
44 | * Functional for real use, but not desired. | |
45 | * 200-299: Good. | |
46 | * A correct and usable clocksource. | |
47 | * 300-399: Desired. | |
48 | * A reasonably fast and accurate clocksource. | |
49 | * 400-499: Perfect | |
50 | * The ideal clocksource. A must-use where | |
51 | * available. | |
8e19608e | 52 | * @read: returns a cycle value, passes clocksource as argument |
4614e6ad MD |
53 | * @enable: optional function to enable the clocksource |
54 | * @disable: optional function to disable the clocksource | |
734efb46 JS |
55 | * @mask: bitmask for two's complement |
56 | * subtraction of non 64 bit counters | |
0a544198 | 57 | * @mult: cycle to nanosecond multiplier |
734efb46 | 58 | * @shift: cycle to nanosecond divisor (power of two) |
98962465 | 59 | * @max_idle_ns: max idle time permitted by the clocksource (nsecs) |
b1b73d09 | 60 | * @maxadj: maximum adjustment value to mult (~11%) |
fb82fe2f | 61 | * @max_cycles: maximum safe cycle value which won't overflow on multiplication |
73b08d2a | 62 | * @flags: flags describing special properties |
433bd805 | 63 | * @archdata: arch-specific data |
c54a42b1 | 64 | * @suspend: suspend function for the clocksource, if necessary |
b52f52a0 | 65 | * @resume: resume function for the clocksource, if necessary |
12907fbb TG |
66 | * @mark_unstable: Optional function to inform the clocksource driver that |
67 | * the watchdog marked the clocksource unstable | |
09ac369c | 68 | * @owner: module reference, must be set by clocksource in modules |
09a99820 TG |
69 | * |
70 | * Note: This struct is not used in hotpathes of the timekeeping code | |
71 | * because the timekeeper caches the hot path fields in its own data | |
72 | * structure, so no line cache alignment is required, | |
73 | * | |
74 | * The pointer to the clocksource itself is handed to the read | |
75 | * callback. If you need extra information there you can wrap struct | |
76 | * clocksource into your own struct. Depending on the amount of | |
77 | * information you need you should consider to cache line align that | |
78 | * structure. | |
734efb46 JS |
79 | */ |
80 | struct clocksource { | |
a5a1d1c2 TG |
81 | u64 (*read)(struct clocksource *cs); |
82 | u64 mask; | |
734efb46 JS |
83 | u32 mult; |
84 | u32 shift; | |
98962465 | 85 | u64 max_idle_ns; |
d65670a7 | 86 | u32 maxadj; |
ae7bd11b | 87 | #ifdef CONFIG_ARCH_CLOCKSOURCE_DATA |
433bd805 | 88 | struct arch_clocksource_data archdata; |
0aa366f3 | 89 | #endif |
fb82fe2f | 90 | u64 max_cycles; |
369db4c9 TG |
91 | const char *name; |
92 | struct list_head list; | |
93 | int rating; | |
369db4c9 TG |
94 | int (*enable)(struct clocksource *cs); |
95 | void (*disable)(struct clocksource *cs); | |
96 | unsigned long flags; | |
97 | void (*suspend)(struct clocksource *cs); | |
98 | void (*resume)(struct clocksource *cs); | |
12907fbb | 99 | void (*mark_unstable)(struct clocksource *cs); |
b421b22b | 100 | void (*tick_stable)(struct clocksource *cs); |
5d8b34fd | 101 | |
b1b73d09 | 102 | /* private: */ |
5d8b34fd TG |
103 | #ifdef CONFIG_CLOCKSOURCE_WATCHDOG |
104 | /* Watchdog related data, used by the framework */ | |
105 | struct list_head wd_list; | |
a5a1d1c2 TG |
106 | u64 cs_last; |
107 | u64 wd_last; | |
5d8b34fd | 108 | #endif |
09ac369c | 109 | struct module *owner; |
09a99820 | 110 | }; |
734efb46 | 111 | |
73b08d2a TG |
112 | /* |
113 | * Clock source flags bits:: | |
114 | */ | |
5d8b34fd TG |
115 | #define CLOCK_SOURCE_IS_CONTINUOUS 0x01 |
116 | #define CLOCK_SOURCE_MUST_VERIFY 0x02 | |
117 | ||
118 | #define CLOCK_SOURCE_WATCHDOG 0x10 | |
119 | #define CLOCK_SOURCE_VALID_FOR_HRES 0x20 | |
c55c87c8 | 120 | #define CLOCK_SOURCE_UNSTABLE 0x40 |
5caf4636 | 121 | #define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80 |
332962f2 | 122 | #define CLOCK_SOURCE_RESELECT 0x100 |
73b08d2a | 123 | |
7f9f303a | 124 | /* simplify initialization of mask field */ |
0773cea3 | 125 | #define CLOCKSOURCE_MASK(bits) GENMASK_ULL((bits) - 1, 0) |
734efb46 | 126 | |
7aca0c07 AK |
127 | static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from) |
128 | { | |
129 | /* freq = cyc/from | |
130 | * mult/2^shift = ns/cyc | |
131 | * mult = ns/cyc * 2^shift | |
132 | * mult = from/freq * 2^shift | |
133 | * mult = from * 2^shift / freq | |
134 | * mult = (from<<shift) / freq | |
135 | */ | |
136 | u64 tmp = ((u64)from) << shift_constant; | |
137 | ||
138 | tmp += freq/2; /* round for do_div */ | |
139 | do_div(tmp, freq); | |
140 | ||
141 | return (u32)tmp; | |
142 | } | |
143 | ||
734efb46 JS |
144 | /** |
145 | * clocksource_khz2mult - calculates mult from khz and shift | |
146 | * @khz: Clocksource frequency in KHz | |
147 | * @shift_constant: Clocksource shift factor | |
148 | * | |
149 | * Helper functions that converts a khz counter frequency to a timsource | |
150 | * multiplier, given the clocksource shift value | |
151 | */ | |
152 | static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant) | |
153 | { | |
7aca0c07 | 154 | return clocksource_freq2mult(khz, shift_constant, NSEC_PER_MSEC); |
734efb46 JS |
155 | } |
156 | ||
157 | /** | |
158 | * clocksource_hz2mult - calculates mult from hz and shift | |
159 | * @hz: Clocksource frequency in Hz | |
160 | * @shift_constant: Clocksource shift factor | |
161 | * | |
162 | * Helper functions that converts a hz counter | |
163 | * frequency to a timsource multiplier, given the | |
164 | * clocksource shift value | |
165 | */ | |
166 | static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant) | |
167 | { | |
7aca0c07 | 168 | return clocksource_freq2mult(hz, shift_constant, NSEC_PER_SEC); |
734efb46 JS |
169 | } |
170 | ||
734efb46 | 171 | /** |
155ec602 | 172 | * clocksource_cyc2ns - converts clocksource cycles to nanoseconds |
b1b73d09 KK |
173 | * @cycles: cycles |
174 | * @mult: cycle to nanosecond multiplier | |
175 | * @shift: cycle to nanosecond divisor (power of two) | |
734efb46 | 176 | * |
ec4101e8 CM |
177 | * Converts clocksource cycles to nanoseconds, using the given @mult and @shift. |
178 | * The code is optimized for performance and is not intended to work | |
179 | * with absolute clocksource cycles (as those will easily overflow), | |
180 | * but is only intended to be used with relative (delta) clocksource cycles. | |
734efb46 JS |
181 | * |
182 | * XXX - This could use some mult_lxl_ll() asm optimization | |
183 | */ | |
a5a1d1c2 | 184 | static inline s64 clocksource_cyc2ns(u64 cycles, u32 mult, u32 shift) |
734efb46 | 185 | { |
155ec602 | 186 | return ((u64) cycles * mult) >> shift; |
5eb6d205 JS |
187 | } |
188 | ||
189 | ||
a89c7edb | 190 | extern int clocksource_unregister(struct clocksource*); |
7c3078b6 | 191 | extern void clocksource_touch_watchdog(void); |
92c7e002 | 192 | extern void clocksource_change_rating(struct clocksource *cs, int rating); |
c54a42b1 | 193 | extern void clocksource_suspend(void); |
b52f52a0 | 194 | extern void clocksource_resume(void); |
96a2adbc | 195 | extern struct clocksource * __init clocksource_default_clock(void); |
7285dd7f | 196 | extern void clocksource_mark_unstable(struct clocksource *cs); |
734efb46 | 197 | |
87d8b9eb | 198 | extern u64 |
fb82fe2f | 199 | clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cycles); |
7d2f944a TG |
200 | extern void |
201 | clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec); | |
202 | ||
d7e81c26 JS |
203 | /* |
204 | * Don't call __clocksource_register_scale directly, use | |
205 | * clocksource_register_hz/khz | |
206 | */ | |
207 | extern int | |
208 | __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq); | |
852db46d | 209 | extern void |
fba9e072 | 210 | __clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq); |
d7e81c26 | 211 | |
f8935983 JS |
212 | /* |
213 | * Don't call this unless you are a default clocksource | |
214 | * (AKA: jiffies) and absolutely have to. | |
215 | */ | |
216 | static inline int __clocksource_register(struct clocksource *cs) | |
217 | { | |
218 | return __clocksource_register_scale(cs, 1, 0); | |
219 | } | |
220 | ||
d7e81c26 JS |
221 | static inline int clocksource_register_hz(struct clocksource *cs, u32 hz) |
222 | { | |
223 | return __clocksource_register_scale(cs, 1, hz); | |
224 | } | |
225 | ||
226 | static inline int clocksource_register_khz(struct clocksource *cs, u32 khz) | |
227 | { | |
228 | return __clocksource_register_scale(cs, 1000, khz); | |
229 | } | |
230 | ||
fba9e072 | 231 | static inline void __clocksource_update_freq_hz(struct clocksource *cs, u32 hz) |
852db46d | 232 | { |
fba9e072 | 233 | __clocksource_update_freq_scale(cs, 1, hz); |
852db46d JS |
234 | } |
235 | ||
fba9e072 | 236 | static inline void __clocksource_update_freq_khz(struct clocksource *cs, u32 khz) |
852db46d | 237 | { |
fba9e072 | 238 | __clocksource_update_freq_scale(cs, 1000, khz); |
852db46d | 239 | } |
d7e81c26 | 240 | |
acc9a9dc | 241 | |
ba919d1c | 242 | extern int timekeeping_notify(struct clocksource *clock); |
75c5158f | 243 | |
a5a1d1c2 TG |
244 | extern u64 clocksource_mmio_readl_up(struct clocksource *); |
245 | extern u64 clocksource_mmio_readl_down(struct clocksource *); | |
246 | extern u64 clocksource_mmio_readw_up(struct clocksource *); | |
247 | extern u64 clocksource_mmio_readw_down(struct clocksource *); | |
442c8176 RK |
248 | |
249 | extern int clocksource_mmio_init(void __iomem *, const char *, | |
a5a1d1c2 | 250 | unsigned long, int, unsigned, u64 (*)(struct clocksource *)); |
442c8176 | 251 | |
8c414ff3 RK |
252 | extern int clocksource_i8253_init(void); |
253 | ||
17273395 | 254 | #define TIMER_OF_DECLARE(name, compat, fn) \ |
2fcc112a | 255 | OF_DECLARE_1_RET(timer, name, compat, fn) |
b7c4db86 | 256 | |
54196ccb | 257 | #define CLOCKSOURCE_OF_DECLARE(name, compat, fn) \ |
8b7a3b56 | 258 | TIMER_OF_DECLARE(name, compat, fn) |
b7c4db86 | 259 | |
bb0eb050 | 260 | #ifdef CONFIG_TIMER_PROBE |
ba5d08c0 | 261 | extern void timer_probe(void); |
e1d7ef1c | 262 | #else |
ba5d08c0 | 263 | static inline void timer_probe(void) {} |
ae278a93 SW |
264 | #endif |
265 | ||
77d62f53 | 266 | #define TIMER_ACPI_DECLARE(name, table_id, fn) \ |
2fcc112a | 267 | ACPI_DECLARE_PROBE_ENTRY(timer, name, table_id, 0, NULL, 0, fn) |
c625f76a | 268 | |
734efb46 | 269 | #endif /* _LINUX_CLOCKSOURCE_H */ |