Rev 6936 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
6588 | serge | 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 |
||
12 | #include |
||
13 | #include |
||
14 | #include |
||
15 | #include |
||
6934 | serge | 16 | #include |
6588 | serge | 17 | #include |
18 | #include |
||
19 | #include |
||
20 | |||
21 | struct clocksource; |
||
22 | struct module; |
||
23 | |||
24 | #ifdef CONFIG_ARCH_CLOCKSOURCE_DATA |
||
25 | #include |
||
26 | #endif |
||
27 | |||
28 | /** |
||
29 | * struct clocksource - hardware abstraction for a free running counter |
||
30 | * Provides mostly state-free accessors to the underlying hardware. |
||
31 | * This is the structure used for system time. |
||
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. |
||
50 | * @read: returns a cycle value, passes clocksource as argument |
||
51 | * @enable: optional function to enable the clocksource |
||
52 | * @disable: optional function to disable the clocksource |
||
53 | * @mask: bitmask for two's complement |
||
54 | * subtraction of non 64 bit counters |
||
55 | * @mult: cycle to nanosecond multiplier |
||
56 | * @shift: cycle to nanosecond divisor (power of two) |
||
57 | * @max_idle_ns: max idle time permitted by the clocksource (nsecs) |
||
58 | * @maxadj: maximum adjustment value to mult (~11%) |
||
59 | * @max_cycles: maximum safe cycle value which won't overflow on multiplication |
||
60 | * @flags: flags describing special properties |
||
61 | * @archdata: arch-specific data |
||
62 | * @suspend: suspend function for the clocksource, if necessary |
||
63 | * @resume: resume function for the clocksource, if necessary |
||
64 | * @owner: module reference, must be set by clocksource in modules |
||
6936 | serge | 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. |
||
6588 | serge | 75 | */ |
76 | struct clocksource { |
||
77 | cycle_t (*read)(struct clocksource *cs); |
||
78 | cycle_t mask; |
||
79 | u32 mult; |
||
80 | u32 shift; |
||
81 | u64 max_idle_ns; |
||
82 | u32 maxadj; |
||
83 | #ifdef CONFIG_ARCH_CLOCKSOURCE_DATA |
||
84 | struct arch_clocksource_data archdata; |
||
85 | #endif |
||
86 | u64 max_cycles; |
||
87 | const char *name; |
||
88 | struct list_head list; |
||
89 | int rating; |
||
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); |
||
95 | |||
96 | /* private: */ |
||
97 | #ifdef CONFIG_CLOCKSOURCE_WATCHDOG |
||
98 | /* Watchdog related data, used by the framework */ |
||
99 | struct list_head wd_list; |
||
100 | cycle_t cs_last; |
||
101 | cycle_t wd_last; |
||
102 | #endif |
||
103 | struct module *owner; |
||
6936 | serge | 104 | }; |
6588 | serge | 105 | |
106 | /* |
||
107 | * Clock source flags bits:: |
||
108 | */ |
||
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 |
||
114 | #define CLOCK_SOURCE_UNSTABLE 0x40 |
||
115 | #define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80 |
||
116 | #define CLOCK_SOURCE_RESELECT 0x100 |
||
117 | |||
118 | /* simplify initialization of mask field */ |
||
119 | #define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1) |
||
120 | |||
7143 | serge | 121 | static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from) |
122 | { |
||
123 | /* freq = cyc/from |
||
124 | * mult/2^shift = ns/cyc |
||
125 | * mult = ns/cyc * 2^shift |
||
126 | * mult = from/freq * 2^shift |
||
127 | * mult = from * 2^shift / freq |
||
128 | * mult = (from< |
||
129 | */ |
||
130 | u64 tmp = ((u64)from) << shift_constant; |
||
131 | |||
132 | tmp += freq/2; /* round for do_div */ |
||
133 | do_div(tmp, freq); |
||
134 | |||
135 | return (u32)tmp; |
||
136 | } |
||
137 | |||
6588 | serge | 138 | /** |
139 | * clocksource_khz2mult - calculates mult from khz and shift |
||
140 | * @khz: Clocksource frequency in KHz |
||
141 | * @shift_constant: Clocksource shift factor |
||
142 | * |
||
143 | * Helper functions that converts a khz counter frequency to a timsource |
||
144 | * multiplier, given the clocksource shift value |
||
145 | */ |
||
146 | static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant) |
||
147 | { |
||
7143 | serge | 148 | return clocksource_freq2mult(khz, shift_constant, NSEC_PER_MSEC); |
6588 | serge | 149 | } |
150 | |||
151 | /** |
||
152 | * clocksource_hz2mult - calculates mult from hz and shift |
||
153 | * @hz: Clocksource frequency in Hz |
||
154 | * @shift_constant: Clocksource shift factor |
||
155 | * |
||
156 | * Helper functions that converts a hz counter |
||
157 | * frequency to a timsource multiplier, given the |
||
158 | * clocksource shift value |
||
159 | */ |
||
160 | static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant) |
||
161 | { |
||
7143 | serge | 162 | return clocksource_freq2mult(hz, shift_constant, NSEC_PER_SEC); |
6588 | serge | 163 | } |
164 | |||
165 | /** |
||
166 | * clocksource_cyc2ns - converts clocksource cycles to nanoseconds |
||
167 | * @cycles: cycles |
||
168 | * @mult: cycle to nanosecond multiplier |
||
169 | * @shift: cycle to nanosecond divisor (power of two) |
||
170 | * |
||
171 | * Converts cycles to nanoseconds, using the given mult and shift. |
||
172 | * |
||
173 | * XXX - This could use some mult_lxl_ll() asm optimization |
||
174 | */ |
||
175 | static inline s64 clocksource_cyc2ns(cycle_t cycles, u32 mult, u32 shift) |
||
176 | { |
||
177 | return ((u64) cycles * mult) >> shift; |
||
178 | } |
||
179 | |||
180 | |||
181 | extern int clocksource_unregister(struct clocksource*); |
||
182 | extern void clocksource_touch_watchdog(void); |
||
183 | extern void clocksource_change_rating(struct clocksource *cs, int rating); |
||
184 | extern void clocksource_suspend(void); |
||
185 | extern void clocksource_resume(void); |
||
186 | extern struct clocksource * __init clocksource_default_clock(void); |
||
187 | extern void clocksource_mark_unstable(struct clocksource *cs); |
||
188 | |||
189 | extern u64 |
||
190 | clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cycles); |
||
191 | extern void |
||
192 | clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec); |
||
193 | |||
194 | /* |
||
195 | * Don't call __clocksource_register_scale directly, use |
||
196 | * clocksource_register_hz/khz |
||
197 | */ |
||
198 | extern int |
||
199 | __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq); |
||
200 | extern void |
||
201 | __clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq); |
||
202 | |||
203 | /* |
||
204 | * Don't call this unless you are a default clocksource |
||
205 | * (AKA: jiffies) and absolutely have to. |
||
206 | */ |
||
207 | static inline int __clocksource_register(struct clocksource *cs) |
||
208 | { |
||
209 | return __clocksource_register_scale(cs, 1, 0); |
||
210 | } |
||
211 | |||
212 | static inline int clocksource_register_hz(struct clocksource *cs, u32 hz) |
||
213 | { |
||
214 | return __clocksource_register_scale(cs, 1, hz); |
||
215 | } |
||
216 | |||
217 | static inline int clocksource_register_khz(struct clocksource *cs, u32 khz) |
||
218 | { |
||
219 | return __clocksource_register_scale(cs, 1000, khz); |
||
220 | } |
||
221 | |||
222 | static inline void __clocksource_update_freq_hz(struct clocksource *cs, u32 hz) |
||
223 | { |
||
224 | __clocksource_update_freq_scale(cs, 1, hz); |
||
225 | } |
||
226 | |||
227 | static inline void __clocksource_update_freq_khz(struct clocksource *cs, u32 khz) |
||
228 | { |
||
229 | __clocksource_update_freq_scale(cs, 1000, khz); |
||
230 | } |
||
231 | |||
232 | |||
233 | extern int timekeeping_notify(struct clocksource *clock); |
||
234 | |||
235 | extern cycle_t clocksource_mmio_readl_up(struct clocksource *); |
||
236 | extern cycle_t clocksource_mmio_readl_down(struct clocksource *); |
||
237 | extern cycle_t clocksource_mmio_readw_up(struct clocksource *); |
||
238 | extern cycle_t clocksource_mmio_readw_down(struct clocksource *); |
||
239 | |||
240 | extern int clocksource_mmio_init(void __iomem *, const char *, |
||
241 | unsigned long, int, unsigned, cycle_t (*)(struct clocksource *)); |
||
242 | |||
243 | extern int clocksource_i8253_init(void); |
||
244 | |||
245 | #define CLOCKSOURCE_OF_DECLARE(name, compat, fn) \ |
||
246 | OF_DECLARE_1(clksrc, name, compat, fn) |
||
247 | |||
248 | #ifdef CONFIG_CLKSRC_PROBE |
||
249 | extern void clocksource_probe(void); |
||
250 | #else |
||
251 | static inline void clocksource_probe(void) {} |
||
252 | #endif |
||
253 | |||
254 | #define CLOCKSOURCE_ACPI_DECLARE(name, table_id, fn) \ |
||
255 | ACPI_DECLARE_PROBE_ENTRY(clksrc, name, table_id, 0, NULL, 0, fn) |
||
256 | |||
257 | #endif /* _LINUX_CLOCKSOURCE_H */><> |