Commit | Line | Data |
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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
734efb46 | 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> |
b2c67cbe | 20 | #include <linux/clocksource_ids.h> |
734efb46 | 21 | #include <asm/div64.h> |
22 | #include <asm/io.h> | |
23 | ||
5d8b34fd | 24 | struct clocksource; |
09ac369c | 25 | struct module; |
734efb46 | 26 | |
5d51bee7 | 27 | #if defined(CONFIG_ARCH_CLOCKSOURCE_DATA) || \ |
f86fd32d | 28 | defined(CONFIG_GENERIC_GETTIMEOFDAY) |
433bd805 | 29 | #include <asm/clocksource.h> |
ae7bd11b | 30 | #endif |
433bd805 | 31 | |
14ee2ac6 | 32 | #include <vdso/clocksource.h> |
5d51bee7 | 33 | |
734efb46 | 34 | /** |
35 | * struct clocksource - hardware abstraction for a free running counter | |
36 | * Provides mostly state-free accessors to the underlying hardware. | |
a038a353 | 37 | * This is the structure used for system time. |
734efb46 | 38 | * |
3bd142a4 TG |
39 | * @read: Returns a cycle value, passes clocksource as argument |
40 | * @mask: Bitmask for two's complement | |
41 | * subtraction of non 64 bit counters | |
42 | * @mult: Cycle to nanosecond multiplier | |
43 | * @shift: Cycle to nanosecond divisor (power of two) | |
44 | * @max_idle_ns: Maximum idle time permitted by the clocksource (nsecs) | |
45 | * @maxadj: Maximum adjustment value to mult (~11%) | |
2e27e793 PM |
46 | * @uncertainty_margin: Maximum uncertainty in nanoseconds per half second. |
47 | * Zero says to use default WATCHDOG_THRESHOLD. | |
3bd142a4 TG |
48 | * @archdata: Optional arch-specific data |
49 | * @max_cycles: Maximum safe cycle value which won't overflow on | |
50 | * multiplication | |
51 | * @name: Pointer to clocksource name | |
52 | * @list: List head for registration (internal) | |
53 | * @rating: Rating value for selection (higher is better) | |
734efb46 | 54 | * To avoid rating inflation the following |
55 | * list should give you a guide as to how | |
56 | * to assign your clocksource a rating | |
57 | * 1-99: Unfit for real use | |
58 | * Only available for bootup and testing purposes. | |
59 | * 100-199: Base level usability. | |
60 | * Functional for real use, but not desired. | |
61 | * 200-299: Good. | |
62 | * A correct and usable clocksource. | |
63 | * 300-399: Desired. | |
64 | * A reasonably fast and accurate clocksource. | |
65 | * 400-499: Perfect | |
66 | * The ideal clocksource. A must-use where | |
67 | * available. | |
b2c67cbe TG |
68 | * @id: Defaults to CSID_GENERIC. The id value is captured |
69 | * in certain snapshot functions to allow callers to | |
70 | * validate the clocksource from which the snapshot was | |
71 | * taken. | |
3bd142a4 TG |
72 | * @flags: Flags describing special properties |
73 | * @enable: Optional function to enable the clocksource | |
74 | * @disable: Optional function to disable the clocksource | |
75 | * @suspend: Optional suspend function for the clocksource | |
76 | * @resume: Optional resume function for the clocksource | |
12907fbb TG |
77 | * @mark_unstable: Optional function to inform the clocksource driver that |
78 | * the watchdog marked the clocksource unstable | |
3bd142a4 | 79 | * @tick_stable: Optional function called periodically from the watchdog |
4bf07f65 | 80 | * code to provide stable synchronization points |
3bd142a4 TG |
81 | * @wd_list: List head to enqueue into the watchdog list (internal) |
82 | * @cs_last: Last clocksource value for clocksource watchdog | |
83 | * @wd_last: Last watchdog value corresponding to @cs_last | |
84 | * @owner: Module reference, must be set by clocksource in modules | |
09a99820 TG |
85 | * |
86 | * Note: This struct is not used in hotpathes of the timekeeping code | |
87 | * because the timekeeper caches the hot path fields in its own data | |
3bd142a4 | 88 | * structure, so no cache line alignment is required, |
09a99820 TG |
89 | * |
90 | * The pointer to the clocksource itself is handed to the read | |
91 | * callback. If you need extra information there you can wrap struct | |
92 | * clocksource into your own struct. Depending on the amount of | |
93 | * information you need you should consider to cache line align that | |
94 | * structure. | |
734efb46 | 95 | */ |
96 | struct clocksource { | |
3bd142a4 TG |
97 | u64 (*read)(struct clocksource *cs); |
98 | u64 mask; | |
99 | u32 mult; | |
100 | u32 shift; | |
101 | u64 max_idle_ns; | |
102 | u32 maxadj; | |
2e27e793 | 103 | u32 uncertainty_margin; |
ae7bd11b | 104 | #ifdef CONFIG_ARCH_CLOCKSOURCE_DATA |
433bd805 | 105 | struct arch_clocksource_data archdata; |
0aa366f3 | 106 | #endif |
3bd142a4 TG |
107 | u64 max_cycles; |
108 | const char *name; | |
109 | struct list_head list; | |
110 | int rating; | |
b2c67cbe | 111 | enum clocksource_ids id; |
5d51bee7 | 112 | enum vdso_clock_mode vdso_clock_mode; |
3bd142a4 TG |
113 | unsigned long flags; |
114 | ||
115 | int (*enable)(struct clocksource *cs); | |
116 | void (*disable)(struct clocksource *cs); | |
117 | void (*suspend)(struct clocksource *cs); | |
118 | void (*resume)(struct clocksource *cs); | |
119 | void (*mark_unstable)(struct clocksource *cs); | |
120 | void (*tick_stable)(struct clocksource *cs); | |
5d8b34fd | 121 | |
b1b73d09 | 122 | /* private: */ |
5d8b34fd TG |
123 | #ifdef CONFIG_CLOCKSOURCE_WATCHDOG |
124 | /* Watchdog related data, used by the framework */ | |
3bd142a4 TG |
125 | struct list_head wd_list; |
126 | u64 cs_last; | |
127 | u64 wd_last; | |
5d8b34fd | 128 | #endif |
3bd142a4 | 129 | struct module *owner; |
09a99820 | 130 | }; |
734efb46 | 131 | |
73b08d2a TG |
132 | /* |
133 | * Clock source flags bits:: | |
134 | */ | |
5d8b34fd TG |
135 | #define CLOCK_SOURCE_IS_CONTINUOUS 0x01 |
136 | #define CLOCK_SOURCE_MUST_VERIFY 0x02 | |
137 | ||
138 | #define CLOCK_SOURCE_WATCHDOG 0x10 | |
139 | #define CLOCK_SOURCE_VALID_FOR_HRES 0x20 | |
c55c87c8 | 140 | #define CLOCK_SOURCE_UNSTABLE 0x40 |
5caf4636 | 141 | #define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80 |
332962f2 | 142 | #define CLOCK_SOURCE_RESELECT 0x100 |
7560c02b | 143 | #define CLOCK_SOURCE_VERIFY_PERCPU 0x200 |
7f9f303a | 144 | /* simplify initialization of mask field */ |
0773cea3 | 145 | #define CLOCKSOURCE_MASK(bits) GENMASK_ULL((bits) - 1, 0) |
734efb46 | 146 | |
7aca0c07 AK |
147 | static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from) |
148 | { | |
149 | /* freq = cyc/from | |
150 | * mult/2^shift = ns/cyc | |
151 | * mult = ns/cyc * 2^shift | |
152 | * mult = from/freq * 2^shift | |
153 | * mult = from * 2^shift / freq | |
154 | * mult = (from<<shift) / freq | |
155 | */ | |
156 | u64 tmp = ((u64)from) << shift_constant; | |
157 | ||
158 | tmp += freq/2; /* round for do_div */ | |
159 | do_div(tmp, freq); | |
160 | ||
161 | return (u32)tmp; | |
162 | } | |
163 | ||
734efb46 | 164 | /** |
165 | * clocksource_khz2mult - calculates mult from khz and shift | |
166 | * @khz: Clocksource frequency in KHz | |
167 | * @shift_constant: Clocksource shift factor | |
168 | * | |
169 | * Helper functions that converts a khz counter frequency to a timsource | |
170 | * multiplier, given the clocksource shift value | |
171 | */ | |
172 | static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant) | |
173 | { | |
7aca0c07 | 174 | return clocksource_freq2mult(khz, shift_constant, NSEC_PER_MSEC); |
734efb46 | 175 | } |
176 | ||
177 | /** | |
178 | * clocksource_hz2mult - calculates mult from hz and shift | |
179 | * @hz: Clocksource frequency in Hz | |
180 | * @shift_constant: Clocksource shift factor | |
181 | * | |
182 | * Helper functions that converts a hz counter | |
183 | * frequency to a timsource multiplier, given the | |
184 | * clocksource shift value | |
185 | */ | |
186 | static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant) | |
187 | { | |
7aca0c07 | 188 | return clocksource_freq2mult(hz, shift_constant, NSEC_PER_SEC); |
734efb46 | 189 | } |
190 | ||
734efb46 | 191 | /** |
155ec602 | 192 | * clocksource_cyc2ns - converts clocksource cycles to nanoseconds |
b1b73d09 KK |
193 | * @cycles: cycles |
194 | * @mult: cycle to nanosecond multiplier | |
195 | * @shift: cycle to nanosecond divisor (power of two) | |
734efb46 | 196 | * |
ec4101e8 CM |
197 | * Converts clocksource cycles to nanoseconds, using the given @mult and @shift. |
198 | * The code is optimized for performance and is not intended to work | |
199 | * with absolute clocksource cycles (as those will easily overflow), | |
200 | * but is only intended to be used with relative (delta) clocksource cycles. | |
734efb46 | 201 | * |
202 | * XXX - This could use some mult_lxl_ll() asm optimization | |
203 | */ | |
a5a1d1c2 | 204 | static inline s64 clocksource_cyc2ns(u64 cycles, u32 mult, u32 shift) |
734efb46 | 205 | { |
155ec602 | 206 | return ((u64) cycles * mult) >> shift; |
5eb6d205 | 207 | } |
208 | ||
209 | ||
a89c7edb | 210 | extern int clocksource_unregister(struct clocksource*); |
7c3078b6 | 211 | extern void clocksource_touch_watchdog(void); |
92c7e002 | 212 | extern void clocksource_change_rating(struct clocksource *cs, int rating); |
c54a42b1 | 213 | extern void clocksource_suspend(void); |
b52f52a0 | 214 | extern void clocksource_resume(void); |
96a2adbc | 215 | extern struct clocksource * __init clocksource_default_clock(void); |
7285dd7f | 216 | extern void clocksource_mark_unstable(struct clocksource *cs); |
39232ed5 BW |
217 | extern void |
218 | clocksource_start_suspend_timing(struct clocksource *cs, u64 start_cycles); | |
219 | extern u64 clocksource_stop_suspend_timing(struct clocksource *cs, u64 now); | |
734efb46 | 220 | |
87d8b9eb | 221 | extern u64 |
fb82fe2f | 222 | clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cycles); |
7d2f944a TG |
223 | extern void |
224 | clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec); | |
225 | ||
d7e81c26 JS |
226 | /* |
227 | * Don't call __clocksource_register_scale directly, use | |
228 | * clocksource_register_hz/khz | |
229 | */ | |
230 | extern int | |
231 | __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq); | |
852db46d | 232 | extern void |
fba9e072 | 233 | __clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq); |
d7e81c26 | 234 | |
f8935983 JS |
235 | /* |
236 | * Don't call this unless you are a default clocksource | |
237 | * (AKA: jiffies) and absolutely have to. | |
238 | */ | |
239 | static inline int __clocksource_register(struct clocksource *cs) | |
240 | { | |
241 | return __clocksource_register_scale(cs, 1, 0); | |
242 | } | |
243 | ||
d7e81c26 JS |
244 | static inline int clocksource_register_hz(struct clocksource *cs, u32 hz) |
245 | { | |
246 | return __clocksource_register_scale(cs, 1, hz); | |
247 | } | |
248 | ||
249 | static inline int clocksource_register_khz(struct clocksource *cs, u32 khz) | |
250 | { | |
251 | return __clocksource_register_scale(cs, 1000, khz); | |
252 | } | |
253 | ||
fba9e072 | 254 | static inline void __clocksource_update_freq_hz(struct clocksource *cs, u32 hz) |
852db46d | 255 | { |
fba9e072 | 256 | __clocksource_update_freq_scale(cs, 1, hz); |
852db46d JS |
257 | } |
258 | ||
fba9e072 | 259 | static inline void __clocksource_update_freq_khz(struct clocksource *cs, u32 khz) |
852db46d | 260 | { |
fba9e072 | 261 | __clocksource_update_freq_scale(cs, 1000, khz); |
852db46d | 262 | } |
d7e81c26 | 263 | |
d67f34c1 TG |
264 | #ifdef CONFIG_ARCH_CLOCKSOURCE_INIT |
265 | extern void clocksource_arch_init(struct clocksource *cs); | |
266 | #else | |
267 | static inline void clocksource_arch_init(struct clocksource *cs) { } | |
268 | #endif | |
acc9a9dc | 269 | |
ba919d1c | 270 | extern int timekeeping_notify(struct clocksource *clock); |
75c5158f | 271 | |
a5a1d1c2 TG |
272 | extern u64 clocksource_mmio_readl_up(struct clocksource *); |
273 | extern u64 clocksource_mmio_readl_down(struct clocksource *); | |
274 | extern u64 clocksource_mmio_readw_up(struct clocksource *); | |
275 | extern u64 clocksource_mmio_readw_down(struct clocksource *); | |
442c8176 RK |
276 | |
277 | extern int clocksource_mmio_init(void __iomem *, const char *, | |
a5a1d1c2 | 278 | unsigned long, int, unsigned, u64 (*)(struct clocksource *)); |
442c8176 | 279 | |
8c414ff3 RK |
280 | extern int clocksource_i8253_init(void); |
281 | ||
17273395 | 282 | #define TIMER_OF_DECLARE(name, compat, fn) \ |
2fcc112a | 283 | OF_DECLARE_1_RET(timer, name, compat, fn) |
b7c4db86 | 284 | |
bb0eb050 | 285 | #ifdef CONFIG_TIMER_PROBE |
ba5d08c0 | 286 | extern void timer_probe(void); |
e1d7ef1c | 287 | #else |
ba5d08c0 | 288 | static inline void timer_probe(void) {} |
ae278a93 SW |
289 | #endif |
290 | ||
77d62f53 | 291 | #define TIMER_ACPI_DECLARE(name, table_id, fn) \ |
2fcc112a | 292 | ACPI_DECLARE_PROBE_ENTRY(timer, name, table_id, 0, NULL, 0, fn) |
c625f76a | 293 | |
1253b9b8 PM |
294 | extern ulong max_cswd_read_retries; |
295 | void clocksource_verify_percpu(struct clocksource *cs); | |
296 | ||
734efb46 | 297 | #endif /* _LINUX_CLOCKSOURCE_H */ |