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734efb46 JS |
1 | /* linux/include/linux/clocksource.h |
2 | * | |
3 | * This file contains the structure definitions for clocksources. | |
4 | * | |
5 | * If you are not a clocksource, or timekeeping code, you should | |
6 | * not be including this file! | |
7 | */ | |
8 | #ifndef _LINUX_CLOCKSOURCE_H | |
9 | #define _LINUX_CLOCKSOURCE_H | |
10 | ||
11 | #include <linux/types.h> | |
12 | #include <linux/timex.h> | |
13 | #include <linux/time.h> | |
14 | #include <linux/list.h> | |
329c8d84 | 15 | #include <linux/cache.h> |
5d8b34fd | 16 | #include <linux/timer.h> |
f1b82746 | 17 | #include <linux/init.h> |
734efb46 JS |
18 | #include <asm/div64.h> |
19 | #include <asm/io.h> | |
20 | ||
5d8b34fd | 21 | struct clocksource; |
09ac369c | 22 | struct module; |
734efb46 | 23 | |
ae7bd11b | 24 | #ifdef CONFIG_ARCH_CLOCKSOURCE_DATA |
433bd805 | 25 | #include <asm/clocksource.h> |
ae7bd11b | 26 | #endif |
433bd805 | 27 | |
734efb46 JS |
28 | /** |
29 | * struct clocksource - hardware abstraction for a free running counter | |
30 | * Provides mostly state-free accessors to the underlying hardware. | |
a038a353 | 31 | * This is the structure used for system time. |
734efb46 JS |
32 | * |
33 | * @name: ptr to clocksource name | |
34 | * @list: list head for registration | |
35 | * @rating: rating value for selection (higher is better) | |
36 | * To avoid rating inflation the following | |
37 | * list should give you a guide as to how | |
38 | * to assign your clocksource a rating | |
39 | * 1-99: Unfit for real use | |
40 | * Only available for bootup and testing purposes. | |
41 | * 100-199: Base level usability. | |
42 | * Functional for real use, but not desired. | |
43 | * 200-299: Good. | |
44 | * A correct and usable clocksource. | |
45 | * 300-399: Desired. | |
46 | * A reasonably fast and accurate clocksource. | |
47 | * 400-499: Perfect | |
48 | * The ideal clocksource. A must-use where | |
49 | * available. | |
8e19608e | 50 | * @read: returns a cycle value, passes clocksource as argument |
4614e6ad MD |
51 | * @enable: optional function to enable the clocksource |
52 | * @disable: optional function to disable the clocksource | |
734efb46 JS |
53 | * @mask: bitmask for two's complement |
54 | * subtraction of non 64 bit counters | |
0a544198 | 55 | * @mult: cycle to nanosecond multiplier |
734efb46 | 56 | * @shift: cycle to nanosecond divisor (power of two) |
98962465 | 57 | * @max_idle_ns: max idle time permitted by the clocksource (nsecs) |
b1b73d09 | 58 | * @maxadj: maximum adjustment value to mult (~11%) |
fb82fe2f | 59 | * @max_cycles: maximum safe cycle value which won't overflow on multiplication |
73b08d2a | 60 | * @flags: flags describing special properties |
433bd805 | 61 | * @archdata: arch-specific data |
c54a42b1 | 62 | * @suspend: suspend function for the clocksource, if necessary |
b52f52a0 | 63 | * @resume: resume function for the clocksource, if necessary |
09ac369c | 64 | * @owner: module reference, must be set by clocksource in modules |
09a99820 TG |
65 | * |
66 | * Note: This struct is not used in hotpathes of the timekeeping code | |
67 | * because the timekeeper caches the hot path fields in its own data | |
68 | * structure, so no line cache alignment is required, | |
69 | * | |
70 | * The pointer to the clocksource itself is handed to the read | |
71 | * callback. If you need extra information there you can wrap struct | |
72 | * clocksource into your own struct. Depending on the amount of | |
73 | * information you need you should consider to cache line align that | |
74 | * structure. | |
734efb46 JS |
75 | */ |
76 | struct clocksource { | |
8e19608e | 77 | cycle_t (*read)(struct clocksource *cs); |
734efb46 JS |
78 | cycle_t mask; |
79 | u32 mult; | |
80 | u32 shift; | |
98962465 | 81 | u64 max_idle_ns; |
d65670a7 | 82 | u32 maxadj; |
ae7bd11b | 83 | #ifdef CONFIG_ARCH_CLOCKSOURCE_DATA |
433bd805 | 84 | struct arch_clocksource_data archdata; |
0aa366f3 | 85 | #endif |
fb82fe2f | 86 | u64 max_cycles; |
369db4c9 TG |
87 | const char *name; |
88 | struct list_head list; | |
89 | int rating; | |
369db4c9 TG |
90 | int (*enable)(struct clocksource *cs); |
91 | void (*disable)(struct clocksource *cs); | |
92 | unsigned long flags; | |
93 | void (*suspend)(struct clocksource *cs); | |
94 | void (*resume)(struct clocksource *cs); | |
5d8b34fd | 95 | |
b1b73d09 | 96 | /* private: */ |
5d8b34fd TG |
97 | #ifdef CONFIG_CLOCKSOURCE_WATCHDOG |
98 | /* Watchdog related data, used by the framework */ | |
99 | struct list_head wd_list; | |
b5199515 | 100 | cycle_t cs_last; |
5d8b34fd TG |
101 | cycle_t wd_last; |
102 | #endif | |
09ac369c | 103 | struct module *owner; |
09a99820 | 104 | }; |
734efb46 | 105 | |
73b08d2a TG |
106 | /* |
107 | * Clock source flags bits:: | |
108 | */ | |
5d8b34fd TG |
109 | #define CLOCK_SOURCE_IS_CONTINUOUS 0x01 |
110 | #define CLOCK_SOURCE_MUST_VERIFY 0x02 | |
111 | ||
112 | #define CLOCK_SOURCE_WATCHDOG 0x10 | |
113 | #define CLOCK_SOURCE_VALID_FOR_HRES 0x20 | |
c55c87c8 | 114 | #define CLOCK_SOURCE_UNSTABLE 0x40 |
5caf4636 | 115 | #define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80 |
332962f2 | 116 | #define CLOCK_SOURCE_RESELECT 0x100 |
73b08d2a | 117 | |
7f9f303a | 118 | /* simplify initialization of mask field */ |
1d76c262 | 119 | #define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1) |
734efb46 JS |
120 | |
121 | /** | |
122 | * clocksource_khz2mult - calculates mult from khz and shift | |
123 | * @khz: Clocksource frequency in KHz | |
124 | * @shift_constant: Clocksource shift factor | |
125 | * | |
126 | * Helper functions that converts a khz counter frequency to a timsource | |
127 | * multiplier, given the clocksource shift value | |
128 | */ | |
129 | static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant) | |
130 | { | |
131 | /* khz = cyc/(Million ns) | |
132 | * mult/2^shift = ns/cyc | |
133 | * mult = ns/cyc * 2^shift | |
134 | * mult = 1Million/khz * 2^shift | |
135 | * mult = 1000000 * 2^shift / khz | |
136 | * mult = (1000000<<shift) / khz | |
137 | */ | |
138 | u64 tmp = ((u64)1000000) << shift_constant; | |
139 | ||
140 | tmp += khz/2; /* round for do_div */ | |
141 | do_div(tmp, khz); | |
142 | ||
143 | return (u32)tmp; | |
144 | } | |
145 | ||
146 | /** | |
147 | * clocksource_hz2mult - calculates mult from hz and shift | |
148 | * @hz: Clocksource frequency in Hz | |
149 | * @shift_constant: Clocksource shift factor | |
150 | * | |
151 | * Helper functions that converts a hz counter | |
152 | * frequency to a timsource multiplier, given the | |
153 | * clocksource shift value | |
154 | */ | |
155 | static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant) | |
156 | { | |
157 | /* hz = cyc/(Billion ns) | |
158 | * mult/2^shift = ns/cyc | |
159 | * mult = ns/cyc * 2^shift | |
160 | * mult = 1Billion/hz * 2^shift | |
161 | * mult = 1000000000 * 2^shift / hz | |
162 | * mult = (1000000000<<shift) / hz | |
163 | */ | |
164 | u64 tmp = ((u64)1000000000) << shift_constant; | |
165 | ||
166 | tmp += hz/2; /* round for do_div */ | |
167 | do_div(tmp, hz); | |
168 | ||
169 | return (u32)tmp; | |
170 | } | |
171 | ||
734efb46 | 172 | /** |
155ec602 | 173 | * clocksource_cyc2ns - converts clocksource cycles to nanoseconds |
b1b73d09 KK |
174 | * @cycles: cycles |
175 | * @mult: cycle to nanosecond multiplier | |
176 | * @shift: cycle to nanosecond divisor (power of two) | |
734efb46 | 177 | * |
155ec602 | 178 | * Converts cycles to nanoseconds, using the given mult and shift. |
734efb46 JS |
179 | * |
180 | * XXX - This could use some mult_lxl_ll() asm optimization | |
181 | */ | |
155ec602 | 182 | static inline s64 clocksource_cyc2ns(cycle_t cycles, u32 mult, u32 shift) |
734efb46 | 183 | { |
155ec602 | 184 | return ((u64) cycles * mult) >> shift; |
5eb6d205 JS |
185 | } |
186 | ||
187 | ||
a89c7edb | 188 | extern int clocksource_unregister(struct clocksource*); |
7c3078b6 | 189 | extern void clocksource_touch_watchdog(void); |
92c7e002 | 190 | extern void clocksource_change_rating(struct clocksource *cs, int rating); |
c54a42b1 | 191 | extern void clocksource_suspend(void); |
b52f52a0 | 192 | extern void clocksource_resume(void); |
96a2adbc | 193 | extern struct clocksource * __init clocksource_default_clock(void); |
7285dd7f | 194 | extern void clocksource_mark_unstable(struct clocksource *cs); |
734efb46 | 195 | |
87d8b9eb | 196 | extern u64 |
fb82fe2f | 197 | clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cycles); |
7d2f944a TG |
198 | extern void |
199 | clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec); | |
200 | ||
d7e81c26 JS |
201 | /* |
202 | * Don't call __clocksource_register_scale directly, use | |
203 | * clocksource_register_hz/khz | |
204 | */ | |
205 | extern int | |
206 | __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq); | |
852db46d | 207 | extern void |
fba9e072 | 208 | __clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq); |
d7e81c26 | 209 | |
f8935983 JS |
210 | /* |
211 | * Don't call this unless you are a default clocksource | |
212 | * (AKA: jiffies) and absolutely have to. | |
213 | */ | |
214 | static inline int __clocksource_register(struct clocksource *cs) | |
215 | { | |
216 | return __clocksource_register_scale(cs, 1, 0); | |
217 | } | |
218 | ||
d7e81c26 JS |
219 | static inline int clocksource_register_hz(struct clocksource *cs, u32 hz) |
220 | { | |
221 | return __clocksource_register_scale(cs, 1, hz); | |
222 | } | |
223 | ||
224 | static inline int clocksource_register_khz(struct clocksource *cs, u32 khz) | |
225 | { | |
226 | return __clocksource_register_scale(cs, 1000, khz); | |
227 | } | |
228 | ||
fba9e072 | 229 | static inline void __clocksource_update_freq_hz(struct clocksource *cs, u32 hz) |
852db46d | 230 | { |
fba9e072 | 231 | __clocksource_update_freq_scale(cs, 1, hz); |
852db46d JS |
232 | } |
233 | ||
fba9e072 | 234 | static inline void __clocksource_update_freq_khz(struct clocksource *cs, u32 khz) |
852db46d | 235 | { |
fba9e072 | 236 | __clocksource_update_freq_scale(cs, 1000, khz); |
852db46d | 237 | } |
d7e81c26 | 238 | |
acc9a9dc | 239 | |
ba919d1c | 240 | extern int timekeeping_notify(struct clocksource *clock); |
75c5158f | 241 | |
442c8176 RK |
242 | extern cycle_t clocksource_mmio_readl_up(struct clocksource *); |
243 | extern cycle_t clocksource_mmio_readl_down(struct clocksource *); | |
244 | extern cycle_t clocksource_mmio_readw_up(struct clocksource *); | |
245 | extern cycle_t clocksource_mmio_readw_down(struct clocksource *); | |
246 | ||
247 | extern int clocksource_mmio_init(void __iomem *, const char *, | |
248 | unsigned long, int, unsigned, cycle_t (*)(struct clocksource *)); | |
249 | ||
8c414ff3 RK |
250 | extern int clocksource_i8253_init(void); |
251 | ||
54196ccb RH |
252 | #define CLOCKSOURCE_OF_DECLARE(name, compat, fn) \ |
253 | OF_DECLARE_1(clksrc, name, compat, fn) | |
254 | ||
aad83b15 | 255 | #ifdef CONFIG_CLKSRC_PROBE |
3722ed23 | 256 | extern void clocksource_probe(void); |
e1d7ef1c | 257 | #else |
3722ed23 | 258 | static inline void clocksource_probe(void) {} |
ae278a93 SW |
259 | #endif |
260 | ||
c625f76a MZ |
261 | #define CLOCKSOURCE_ACPI_DECLARE(name, table_id, fn) \ |
262 | ACPI_DECLARE_PROBE_ENTRY(clksrc, name, table_id, 0, NULL, 0, fn) | |
263 | ||
734efb46 | 264 | #endif /* _LINUX_CLOCKSOURCE_H */ |