]>
Commit | Line | Data |
---|---|---|
734efb46 JS |
1 | /* |
2 | * linux/kernel/time/clocksource.c | |
3 | * | |
4 | * This file contains the functions which manage clocksource drivers. | |
5 | * | |
6 | * Copyright (C) 2004, 2005 IBM, John Stultz (johnstul@us.ibm.com) | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
21 | * | |
22 | * TODO WishList: | |
23 | * o Allow clocksource drivers to be unregistered | |
734efb46 JS |
24 | */ |
25 | ||
d369a5d8 | 26 | #include <linux/device.h> |
734efb46 | 27 | #include <linux/clocksource.h> |
734efb46 JS |
28 | #include <linux/init.h> |
29 | #include <linux/module.h> | |
dc29a365 | 30 | #include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */ |
79bf2bb3 | 31 | #include <linux/tick.h> |
01548f4d | 32 | #include <linux/kthread.h> |
734efb46 | 33 | |
a038a353 PO |
34 | void timecounter_init(struct timecounter *tc, |
35 | const struct cyclecounter *cc, | |
36 | u64 start_tstamp) | |
37 | { | |
38 | tc->cc = cc; | |
39 | tc->cycle_last = cc->read(cc); | |
40 | tc->nsec = start_tstamp; | |
41 | } | |
3586e0a9 | 42 | EXPORT_SYMBOL_GPL(timecounter_init); |
a038a353 PO |
43 | |
44 | /** | |
45 | * timecounter_read_delta - get nanoseconds since last call of this function | |
46 | * @tc: Pointer to time counter | |
47 | * | |
48 | * When the underlying cycle counter runs over, this will be handled | |
49 | * correctly as long as it does not run over more than once between | |
50 | * calls. | |
51 | * | |
52 | * The first call to this function for a new time counter initializes | |
53 | * the time tracking and returns an undefined result. | |
54 | */ | |
55 | static u64 timecounter_read_delta(struct timecounter *tc) | |
56 | { | |
57 | cycle_t cycle_now, cycle_delta; | |
58 | u64 ns_offset; | |
59 | ||
60 | /* read cycle counter: */ | |
61 | cycle_now = tc->cc->read(tc->cc); | |
62 | ||
63 | /* calculate the delta since the last timecounter_read_delta(): */ | |
64 | cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask; | |
65 | ||
66 | /* convert to nanoseconds: */ | |
67 | ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta); | |
68 | ||
69 | /* update time stamp of timecounter_read_delta() call: */ | |
70 | tc->cycle_last = cycle_now; | |
71 | ||
72 | return ns_offset; | |
73 | } | |
74 | ||
75 | u64 timecounter_read(struct timecounter *tc) | |
76 | { | |
77 | u64 nsec; | |
78 | ||
79 | /* increment time by nanoseconds since last call */ | |
80 | nsec = timecounter_read_delta(tc); | |
81 | nsec += tc->nsec; | |
82 | tc->nsec = nsec; | |
83 | ||
84 | return nsec; | |
85 | } | |
3586e0a9 | 86 | EXPORT_SYMBOL_GPL(timecounter_read); |
a038a353 PO |
87 | |
88 | u64 timecounter_cyc2time(struct timecounter *tc, | |
89 | cycle_t cycle_tstamp) | |
90 | { | |
91 | u64 cycle_delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask; | |
92 | u64 nsec; | |
93 | ||
94 | /* | |
95 | * Instead of always treating cycle_tstamp as more recent | |
96 | * than tc->cycle_last, detect when it is too far in the | |
97 | * future and treat it as old time stamp instead. | |
98 | */ | |
99 | if (cycle_delta > tc->cc->mask / 2) { | |
100 | cycle_delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask; | |
101 | nsec = tc->nsec - cyclecounter_cyc2ns(tc->cc, cycle_delta); | |
102 | } else { | |
103 | nsec = cyclecounter_cyc2ns(tc->cc, cycle_delta) + tc->nsec; | |
104 | } | |
105 | ||
106 | return nsec; | |
107 | } | |
3586e0a9 | 108 | EXPORT_SYMBOL_GPL(timecounter_cyc2time); |
a038a353 | 109 | |
7d2f944a TG |
110 | /** |
111 | * clocks_calc_mult_shift - calculate mult/shift factors for scaled math of clocks | |
112 | * @mult: pointer to mult variable | |
113 | * @shift: pointer to shift variable | |
114 | * @from: frequency to convert from | |
115 | * @to: frequency to convert to | |
5fdade95 | 116 | * @maxsec: guaranteed runtime conversion range in seconds |
7d2f944a TG |
117 | * |
118 | * The function evaluates the shift/mult pair for the scaled math | |
119 | * operations of clocksources and clockevents. | |
120 | * | |
121 | * @to and @from are frequency values in HZ. For clock sources @to is | |
122 | * NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock | |
123 | * event @to is the counter frequency and @from is NSEC_PER_SEC. | |
124 | * | |
5fdade95 | 125 | * The @maxsec conversion range argument controls the time frame in |
7d2f944a TG |
126 | * seconds which must be covered by the runtime conversion with the |
127 | * calculated mult and shift factors. This guarantees that no 64bit | |
128 | * overflow happens when the input value of the conversion is | |
129 | * multiplied with the calculated mult factor. Larger ranges may | |
130 | * reduce the conversion accuracy by chosing smaller mult and shift | |
131 | * factors. | |
132 | */ | |
133 | void | |
5fdade95 | 134 | clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 maxsec) |
7d2f944a TG |
135 | { |
136 | u64 tmp; | |
137 | u32 sft, sftacc= 32; | |
138 | ||
139 | /* | |
140 | * Calculate the shift factor which is limiting the conversion | |
141 | * range: | |
142 | */ | |
5fdade95 | 143 | tmp = ((u64)maxsec * from) >> 32; |
7d2f944a TG |
144 | while (tmp) { |
145 | tmp >>=1; | |
146 | sftacc--; | |
147 | } | |
148 | ||
149 | /* | |
150 | * Find the conversion shift/mult pair which has the best | |
151 | * accuracy and fits the maxsec conversion range: | |
152 | */ | |
153 | for (sft = 32; sft > 0; sft--) { | |
154 | tmp = (u64) to << sft; | |
b5776c4a | 155 | tmp += from / 2; |
7d2f944a TG |
156 | do_div(tmp, from); |
157 | if ((tmp >> sftacc) == 0) | |
158 | break; | |
159 | } | |
160 | *mult = tmp; | |
161 | *shift = sft; | |
162 | } | |
163 | ||
734efb46 JS |
164 | /*[Clocksource internal variables]--------- |
165 | * curr_clocksource: | |
f1b82746 | 166 | * currently selected clocksource. |
734efb46 JS |
167 | * clocksource_list: |
168 | * linked list with the registered clocksources | |
75c5158f MS |
169 | * clocksource_mutex: |
170 | * protects manipulations to curr_clocksource and the clocksource_list | |
734efb46 JS |
171 | * override_name: |
172 | * Name of the user-specified clocksource. | |
173 | */ | |
f1b82746 | 174 | static struct clocksource *curr_clocksource; |
734efb46 | 175 | static LIST_HEAD(clocksource_list); |
75c5158f | 176 | static DEFINE_MUTEX(clocksource_mutex); |
29b54078 TG |
177 | #define CS_NAME_LEN 32 |
178 | static char override_name[CS_NAME_LEN]; | |
54a6bc0b | 179 | static int finished_booting; |
734efb46 | 180 | |
5d8b34fd | 181 | #ifdef CONFIG_CLOCKSOURCE_WATCHDOG |
f79e0258 MS |
182 | static void clocksource_watchdog_work(struct work_struct *work); |
183 | ||
5d8b34fd TG |
184 | static LIST_HEAD(watchdog_list); |
185 | static struct clocksource *watchdog; | |
186 | static struct timer_list watchdog_timer; | |
f79e0258 | 187 | static DECLARE_WORK(watchdog_work, clocksource_watchdog_work); |
5d8b34fd | 188 | static DEFINE_SPINLOCK(watchdog_lock); |
fb63a0eb | 189 | static int watchdog_running; |
9fb60336 | 190 | static atomic_t watchdog_reset_pending; |
b52f52a0 | 191 | |
01548f4d | 192 | static int clocksource_watchdog_kthread(void *data); |
d0981a1b | 193 | static void __clocksource_change_rating(struct clocksource *cs, int rating); |
c55c87c8 | 194 | |
5d8b34fd | 195 | /* |
35c35d1a | 196 | * Interval: 0.5sec Threshold: 0.0625s |
5d8b34fd TG |
197 | */ |
198 | #define WATCHDOG_INTERVAL (HZ >> 1) | |
35c35d1a | 199 | #define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 4) |
5d8b34fd | 200 | |
01548f4d MS |
201 | static void clocksource_watchdog_work(struct work_struct *work) |
202 | { | |
203 | /* | |
204 | * If kthread_run fails the next watchdog scan over the | |
205 | * watchdog_list will find the unstable clock again. | |
206 | */ | |
207 | kthread_run(clocksource_watchdog_kthread, NULL, "kwatchdog"); | |
208 | } | |
209 | ||
7285dd7f | 210 | static void __clocksource_unstable(struct clocksource *cs) |
5d8b34fd | 211 | { |
5d8b34fd | 212 | cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG); |
c55c87c8 | 213 | cs->flags |= CLOCK_SOURCE_UNSTABLE; |
54a6bc0b TG |
214 | if (finished_booting) |
215 | schedule_work(&watchdog_work); | |
5d8b34fd TG |
216 | } |
217 | ||
7285dd7f TG |
218 | static void clocksource_unstable(struct clocksource *cs, int64_t delta) |
219 | { | |
220 | printk(KERN_WARNING "Clocksource %s unstable (delta = %Ld ns)\n", | |
221 | cs->name, delta); | |
222 | __clocksource_unstable(cs); | |
223 | } | |
224 | ||
225 | /** | |
226 | * clocksource_mark_unstable - mark clocksource unstable via watchdog | |
227 | * @cs: clocksource to be marked unstable | |
228 | * | |
229 | * This function is called instead of clocksource_change_rating from | |
230 | * cpu hotplug code to avoid a deadlock between the clocksource mutex | |
231 | * and the cpu hotplug mutex. It defers the update of the clocksource | |
232 | * to the watchdog thread. | |
233 | */ | |
234 | void clocksource_mark_unstable(struct clocksource *cs) | |
235 | { | |
236 | unsigned long flags; | |
237 | ||
238 | spin_lock_irqsave(&watchdog_lock, flags); | |
239 | if (!(cs->flags & CLOCK_SOURCE_UNSTABLE)) { | |
240 | if (list_empty(&cs->wd_list)) | |
241 | list_add(&cs->wd_list, &watchdog_list); | |
242 | __clocksource_unstable(cs); | |
243 | } | |
244 | spin_unlock_irqrestore(&watchdog_lock, flags); | |
245 | } | |
246 | ||
5d8b34fd TG |
247 | static void clocksource_watchdog(unsigned long data) |
248 | { | |
c55c87c8 | 249 | struct clocksource *cs; |
5d8b34fd TG |
250 | cycle_t csnow, wdnow; |
251 | int64_t wd_nsec, cs_nsec; | |
9fb60336 | 252 | int next_cpu, reset_pending; |
5d8b34fd TG |
253 | |
254 | spin_lock(&watchdog_lock); | |
fb63a0eb MS |
255 | if (!watchdog_running) |
256 | goto out; | |
5d8b34fd | 257 | |
9fb60336 TG |
258 | reset_pending = atomic_read(&watchdog_reset_pending); |
259 | ||
c55c87c8 MS |
260 | list_for_each_entry(cs, &watchdog_list, wd_list) { |
261 | ||
262 | /* Clocksource already marked unstable? */ | |
01548f4d | 263 | if (cs->flags & CLOCK_SOURCE_UNSTABLE) { |
54a6bc0b TG |
264 | if (finished_booting) |
265 | schedule_work(&watchdog_work); | |
c55c87c8 | 266 | continue; |
01548f4d | 267 | } |
c55c87c8 | 268 | |
b5199515 | 269 | local_irq_disable(); |
8e19608e | 270 | csnow = cs->read(cs); |
b5199515 TG |
271 | wdnow = watchdog->read(watchdog); |
272 | local_irq_enable(); | |
b52f52a0 | 273 | |
8cf4e750 | 274 | /* Clocksource initialized ? */ |
9fb60336 TG |
275 | if (!(cs->flags & CLOCK_SOURCE_WATCHDOG) || |
276 | atomic_read(&watchdog_reset_pending)) { | |
8cf4e750 | 277 | cs->flags |= CLOCK_SOURCE_WATCHDOG; |
b5199515 TG |
278 | cs->wd_last = wdnow; |
279 | cs->cs_last = csnow; | |
b52f52a0 TG |
280 | continue; |
281 | } | |
282 | ||
b5199515 TG |
283 | wd_nsec = clocksource_cyc2ns((wdnow - cs->wd_last) & watchdog->mask, |
284 | watchdog->mult, watchdog->shift); | |
285 | ||
286 | cs_nsec = clocksource_cyc2ns((csnow - cs->cs_last) & | |
155ec602 | 287 | cs->mask, cs->mult, cs->shift); |
b5199515 TG |
288 | cs->cs_last = csnow; |
289 | cs->wd_last = wdnow; | |
290 | ||
9fb60336 TG |
291 | if (atomic_read(&watchdog_reset_pending)) |
292 | continue; | |
293 | ||
b5199515 | 294 | /* Check the deviation from the watchdog clocksource. */ |
9fb60336 | 295 | if ((abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD)) { |
8cf4e750 MS |
296 | clocksource_unstable(cs, cs_nsec - wd_nsec); |
297 | continue; | |
298 | } | |
299 | ||
300 | if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && | |
301 | (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) && | |
302 | (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) { | |
303 | cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; | |
304 | /* | |
305 | * We just marked the clocksource as highres-capable, | |
306 | * notify the rest of the system as well so that we | |
307 | * transition into high-res mode: | |
308 | */ | |
309 | tick_clock_notify(); | |
5d8b34fd TG |
310 | } |
311 | } | |
312 | ||
9fb60336 TG |
313 | /* |
314 | * We only clear the watchdog_reset_pending, when we did a | |
315 | * full cycle through all clocksources. | |
316 | */ | |
317 | if (reset_pending) | |
318 | atomic_dec(&watchdog_reset_pending); | |
319 | ||
c55c87c8 MS |
320 | /* |
321 | * Cycle through CPUs to check if the CPUs stay synchronized | |
322 | * to each other. | |
323 | */ | |
324 | next_cpu = cpumask_next(raw_smp_processor_id(), cpu_online_mask); | |
325 | if (next_cpu >= nr_cpu_ids) | |
326 | next_cpu = cpumask_first(cpu_online_mask); | |
327 | watchdog_timer.expires += WATCHDOG_INTERVAL; | |
328 | add_timer_on(&watchdog_timer, next_cpu); | |
fb63a0eb | 329 | out: |
5d8b34fd TG |
330 | spin_unlock(&watchdog_lock); |
331 | } | |
0f8e8ef7 | 332 | |
fb63a0eb MS |
333 | static inline void clocksource_start_watchdog(void) |
334 | { | |
335 | if (watchdog_running || !watchdog || list_empty(&watchdog_list)) | |
336 | return; | |
337 | init_timer(&watchdog_timer); | |
338 | watchdog_timer.function = clocksource_watchdog; | |
fb63a0eb MS |
339 | watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL; |
340 | add_timer_on(&watchdog_timer, cpumask_first(cpu_online_mask)); | |
341 | watchdog_running = 1; | |
342 | } | |
343 | ||
344 | static inline void clocksource_stop_watchdog(void) | |
345 | { | |
346 | if (!watchdog_running || (watchdog && !list_empty(&watchdog_list))) | |
347 | return; | |
348 | del_timer(&watchdog_timer); | |
349 | watchdog_running = 0; | |
350 | } | |
351 | ||
0f8e8ef7 MS |
352 | static inline void clocksource_reset_watchdog(void) |
353 | { | |
354 | struct clocksource *cs; | |
355 | ||
356 | list_for_each_entry(cs, &watchdog_list, wd_list) | |
357 | cs->flags &= ~CLOCK_SOURCE_WATCHDOG; | |
358 | } | |
359 | ||
b52f52a0 TG |
360 | static void clocksource_resume_watchdog(void) |
361 | { | |
9fb60336 | 362 | atomic_inc(&watchdog_reset_pending); |
b52f52a0 TG |
363 | } |
364 | ||
fb63a0eb | 365 | static void clocksource_enqueue_watchdog(struct clocksource *cs) |
5d8b34fd | 366 | { |
5d8b34fd TG |
367 | unsigned long flags; |
368 | ||
369 | spin_lock_irqsave(&watchdog_lock, flags); | |
370 | if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) { | |
fb63a0eb | 371 | /* cs is a clocksource to be watched. */ |
5d8b34fd | 372 | list_add(&cs->wd_list, &watchdog_list); |
fb63a0eb | 373 | cs->flags &= ~CLOCK_SOURCE_WATCHDOG; |
948ac6d7 | 374 | } else { |
fb63a0eb | 375 | /* cs is a watchdog. */ |
948ac6d7 | 376 | if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) |
5d8b34fd | 377 | cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; |
fb63a0eb | 378 | /* Pick the best watchdog. */ |
5d8b34fd | 379 | if (!watchdog || cs->rating > watchdog->rating) { |
5d8b34fd | 380 | watchdog = cs; |
5d8b34fd | 381 | /* Reset watchdog cycles */ |
0f8e8ef7 | 382 | clocksource_reset_watchdog(); |
5d8b34fd TG |
383 | } |
384 | } | |
fb63a0eb MS |
385 | /* Check if the watchdog timer needs to be started. */ |
386 | clocksource_start_watchdog(); | |
5d8b34fd TG |
387 | spin_unlock_irqrestore(&watchdog_lock, flags); |
388 | } | |
fb63a0eb MS |
389 | |
390 | static void clocksource_dequeue_watchdog(struct clocksource *cs) | |
391 | { | |
fb63a0eb MS |
392 | unsigned long flags; |
393 | ||
394 | spin_lock_irqsave(&watchdog_lock, flags); | |
a89c7edb TG |
395 | if (cs != watchdog) { |
396 | if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) { | |
397 | /* cs is a watched clocksource. */ | |
398 | list_del_init(&cs->wd_list); | |
399 | /* Check if the watchdog timer needs to be stopped. */ | |
400 | clocksource_stop_watchdog(); | |
fb63a0eb MS |
401 | } |
402 | } | |
fb63a0eb MS |
403 | spin_unlock_irqrestore(&watchdog_lock, flags); |
404 | } | |
405 | ||
01548f4d | 406 | static int clocksource_watchdog_kthread(void *data) |
c55c87c8 MS |
407 | { |
408 | struct clocksource *cs, *tmp; | |
409 | unsigned long flags; | |
6ea41d25 | 410 | LIST_HEAD(unstable); |
c55c87c8 | 411 | |
d0981a1b | 412 | mutex_lock(&clocksource_mutex); |
c55c87c8 MS |
413 | spin_lock_irqsave(&watchdog_lock, flags); |
414 | list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) | |
415 | if (cs->flags & CLOCK_SOURCE_UNSTABLE) { | |
416 | list_del_init(&cs->wd_list); | |
6ea41d25 | 417 | list_add(&cs->wd_list, &unstable); |
c55c87c8 MS |
418 | } |
419 | /* Check if the watchdog timer needs to be stopped. */ | |
420 | clocksource_stop_watchdog(); | |
6ea41d25 TG |
421 | spin_unlock_irqrestore(&watchdog_lock, flags); |
422 | ||
423 | /* Needs to be done outside of watchdog lock */ | |
424 | list_for_each_entry_safe(cs, tmp, &unstable, wd_list) { | |
425 | list_del_init(&cs->wd_list); | |
d0981a1b | 426 | __clocksource_change_rating(cs, 0); |
6ea41d25 | 427 | } |
d0981a1b | 428 | mutex_unlock(&clocksource_mutex); |
01548f4d | 429 | return 0; |
c55c87c8 MS |
430 | } |
431 | ||
7eaeb343 TG |
432 | static bool clocksource_is_watchdog(struct clocksource *cs) |
433 | { | |
434 | return cs == watchdog; | |
435 | } | |
436 | ||
fb63a0eb MS |
437 | #else /* CONFIG_CLOCKSOURCE_WATCHDOG */ |
438 | ||
439 | static void clocksource_enqueue_watchdog(struct clocksource *cs) | |
5d8b34fd TG |
440 | { |
441 | if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) | |
442 | cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; | |
443 | } | |
b52f52a0 | 444 | |
fb63a0eb | 445 | static inline void clocksource_dequeue_watchdog(struct clocksource *cs) { } |
b52f52a0 | 446 | static inline void clocksource_resume_watchdog(void) { } |
54a6bc0b | 447 | static inline int clocksource_watchdog_kthread(void *data) { return 0; } |
7eaeb343 | 448 | static bool clocksource_is_watchdog(struct clocksource *cs) { return false; } |
fb63a0eb MS |
449 | |
450 | #endif /* CONFIG_CLOCKSOURCE_WATCHDOG */ | |
5d8b34fd | 451 | |
c54a42b1 MD |
452 | /** |
453 | * clocksource_suspend - suspend the clocksource(s) | |
454 | */ | |
455 | void clocksource_suspend(void) | |
456 | { | |
457 | struct clocksource *cs; | |
458 | ||
459 | list_for_each_entry_reverse(cs, &clocksource_list, list) | |
460 | if (cs->suspend) | |
461 | cs->suspend(cs); | |
462 | } | |
463 | ||
b52f52a0 TG |
464 | /** |
465 | * clocksource_resume - resume the clocksource(s) | |
466 | */ | |
467 | void clocksource_resume(void) | |
468 | { | |
2e197586 | 469 | struct clocksource *cs; |
b52f52a0 | 470 | |
75c5158f | 471 | list_for_each_entry(cs, &clocksource_list, list) |
b52f52a0 | 472 | if (cs->resume) |
17622339 | 473 | cs->resume(cs); |
b52f52a0 TG |
474 | |
475 | clocksource_resume_watchdog(); | |
b52f52a0 TG |
476 | } |
477 | ||
7c3078b6 JW |
478 | /** |
479 | * clocksource_touch_watchdog - Update watchdog | |
480 | * | |
481 | * Update the watchdog after exception contexts such as kgdb so as not | |
7b7422a5 TG |
482 | * to incorrectly trip the watchdog. This might fail when the kernel |
483 | * was stopped in code which holds watchdog_lock. | |
7c3078b6 JW |
484 | */ |
485 | void clocksource_touch_watchdog(void) | |
486 | { | |
487 | clocksource_resume_watchdog(); | |
488 | } | |
489 | ||
d65670a7 JS |
490 | /** |
491 | * clocksource_max_adjustment- Returns max adjustment amount | |
492 | * @cs: Pointer to clocksource | |
493 | * | |
494 | */ | |
495 | static u32 clocksource_max_adjustment(struct clocksource *cs) | |
496 | { | |
497 | u64 ret; | |
498 | /* | |
88b28adf | 499 | * We won't try to correct for more than 11% adjustments (110,000 ppm), |
d65670a7 JS |
500 | */ |
501 | ret = (u64)cs->mult * 11; | |
502 | do_div(ret,100); | |
503 | return (u32)ret; | |
504 | } | |
505 | ||
98962465 JH |
506 | /** |
507 | * clocksource_max_deferment - Returns max time the clocksource can be deferred | |
508 | * @cs: Pointer to clocksource | |
509 | * | |
510 | */ | |
511 | static u64 clocksource_max_deferment(struct clocksource *cs) | |
512 | { | |
513 | u64 max_nsecs, max_cycles; | |
514 | ||
515 | /* | |
516 | * Calculate the maximum number of cycles that we can pass to the | |
517 | * cyc2ns function without overflowing a 64-bit signed result. The | |
d65670a7 JS |
518 | * maximum number of cycles is equal to ULLONG_MAX/(cs->mult+cs->maxadj) |
519 | * which is equivalent to the below. | |
520 | * max_cycles < (2^63)/(cs->mult + cs->maxadj) | |
521 | * max_cycles < 2^(log2((2^63)/(cs->mult + cs->maxadj))) | |
522 | * max_cycles < 2^(log2(2^63) - log2(cs->mult + cs->maxadj)) | |
523 | * max_cycles < 2^(63 - log2(cs->mult + cs->maxadj)) | |
524 | * max_cycles < 1 << (63 - log2(cs->mult + cs->maxadj)) | |
98962465 JH |
525 | * Please note that we add 1 to the result of the log2 to account for |
526 | * any rounding errors, ensure the above inequality is satisfied and | |
527 | * no overflow will occur. | |
528 | */ | |
d65670a7 | 529 | max_cycles = 1ULL << (63 - (ilog2(cs->mult + cs->maxadj) + 1)); |
98962465 JH |
530 | |
531 | /* | |
532 | * The actual maximum number of cycles we can defer the clocksource is | |
533 | * determined by the minimum of max_cycles and cs->mask. | |
d65670a7 JS |
534 | * Note: Here we subtract the maxadj to make sure we don't sleep for |
535 | * too long if there's a large negative adjustment. | |
98962465 JH |
536 | */ |
537 | max_cycles = min_t(u64, max_cycles, (u64) cs->mask); | |
d65670a7 JS |
538 | max_nsecs = clocksource_cyc2ns(max_cycles, cs->mult - cs->maxadj, |
539 | cs->shift); | |
98962465 JH |
540 | |
541 | /* | |
542 | * To ensure that the clocksource does not wrap whilst we are idle, | |
543 | * limit the time the clocksource can be deferred by 12.5%. Please | |
544 | * note a margin of 12.5% is used because this can be computed with | |
545 | * a shift, versus say 10% which would require division. | |
546 | */ | |
b1f91966 | 547 | return max_nsecs - (max_nsecs >> 3); |
98962465 JH |
548 | } |
549 | ||
592913ec | 550 | #ifndef CONFIG_ARCH_USES_GETTIMEOFFSET |
734efb46 | 551 | |
f5a2e343 | 552 | static struct clocksource *clocksource_find_best(bool oneshot, bool skipcur) |
5d33b883 TG |
553 | { |
554 | struct clocksource *cs; | |
555 | ||
556 | if (!finished_booting || list_empty(&clocksource_list)) | |
557 | return NULL; | |
558 | ||
559 | /* | |
560 | * We pick the clocksource with the highest rating. If oneshot | |
561 | * mode is active, we pick the highres valid clocksource with | |
562 | * the best rating. | |
563 | */ | |
564 | list_for_each_entry(cs, &clocksource_list, list) { | |
f5a2e343 TG |
565 | if (skipcur && cs == curr_clocksource) |
566 | continue; | |
5d33b883 TG |
567 | if (oneshot && !(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES)) |
568 | continue; | |
569 | return cs; | |
570 | } | |
571 | return NULL; | |
572 | } | |
573 | ||
f5a2e343 | 574 | static void __clocksource_select(bool skipcur) |
734efb46 | 575 | { |
5d33b883 | 576 | bool oneshot = tick_oneshot_mode_active(); |
f1b82746 | 577 | struct clocksource *best, *cs; |
5d8b34fd | 578 | |
5d33b883 | 579 | /* Find the best suitable clocksource */ |
f5a2e343 | 580 | best = clocksource_find_best(oneshot, skipcur); |
5d33b883 | 581 | if (!best) |
f1b82746 | 582 | return; |
5d33b883 | 583 | |
f1b82746 MS |
584 | /* Check for the override clocksource. */ |
585 | list_for_each_entry(cs, &clocksource_list, list) { | |
f5a2e343 TG |
586 | if (skipcur && cs == curr_clocksource) |
587 | continue; | |
f1b82746 MS |
588 | if (strcmp(cs->name, override_name) != 0) |
589 | continue; | |
590 | /* | |
591 | * Check to make sure we don't switch to a non-highres | |
592 | * capable clocksource if the tick code is in oneshot | |
593 | * mode (highres or nohz) | |
594 | */ | |
5d33b883 | 595 | if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && oneshot) { |
f1b82746 MS |
596 | /* Override clocksource cannot be used. */ |
597 | printk(KERN_WARNING "Override clocksource %s is not " | |
598 | "HRT compatible. Cannot switch while in " | |
599 | "HRT/NOHZ mode\n", cs->name); | |
600 | override_name[0] = 0; | |
601 | } else | |
602 | /* Override clocksource can be used. */ | |
603 | best = cs; | |
604 | break; | |
605 | } | |
ba919d1c TG |
606 | |
607 | if (curr_clocksource != best && !timekeeping_notify(best)) { | |
608 | pr_info("Switched to clocksource %s\n", best->name); | |
75c5158f | 609 | curr_clocksource = best; |
75c5158f | 610 | } |
f1b82746 | 611 | } |
734efb46 | 612 | |
f5a2e343 TG |
613 | /** |
614 | * clocksource_select - Select the best clocksource available | |
615 | * | |
616 | * Private function. Must hold clocksource_mutex when called. | |
617 | * | |
618 | * Select the clocksource with the best rating, or the clocksource, | |
619 | * which is selected by userspace override. | |
620 | */ | |
621 | static void clocksource_select(void) | |
622 | { | |
623 | return __clocksource_select(false); | |
624 | } | |
625 | ||
7eaeb343 TG |
626 | static void clocksource_select_fallback(void) |
627 | { | |
628 | return __clocksource_select(true); | |
629 | } | |
630 | ||
592913ec | 631 | #else /* !CONFIG_ARCH_USES_GETTIMEOFFSET */ |
54a6bc0b TG |
632 | |
633 | static inline void clocksource_select(void) { } | |
634 | ||
635 | #endif | |
636 | ||
75c5158f MS |
637 | /* |
638 | * clocksource_done_booting - Called near the end of core bootup | |
639 | * | |
640 | * Hack to avoid lots of clocksource churn at boot time. | |
641 | * We use fs_initcall because we want this to start before | |
642 | * device_initcall but after subsys_initcall. | |
643 | */ | |
644 | static int __init clocksource_done_booting(void) | |
645 | { | |
ad6759fb JS |
646 | mutex_lock(&clocksource_mutex); |
647 | curr_clocksource = clocksource_default_clock(); | |
648 | mutex_unlock(&clocksource_mutex); | |
649 | ||
75c5158f | 650 | finished_booting = 1; |
54a6bc0b TG |
651 | |
652 | /* | |
653 | * Run the watchdog first to eliminate unstable clock sources | |
654 | */ | |
655 | clocksource_watchdog_kthread(NULL); | |
656 | ||
e6c73305 | 657 | mutex_lock(&clocksource_mutex); |
75c5158f | 658 | clocksource_select(); |
e6c73305 | 659 | mutex_unlock(&clocksource_mutex); |
75c5158f MS |
660 | return 0; |
661 | } | |
662 | fs_initcall(clocksource_done_booting); | |
663 | ||
92c7e002 TG |
664 | /* |
665 | * Enqueue the clocksource sorted by rating | |
734efb46 | 666 | */ |
f1b82746 | 667 | static void clocksource_enqueue(struct clocksource *cs) |
734efb46 | 668 | { |
f1b82746 MS |
669 | struct list_head *entry = &clocksource_list; |
670 | struct clocksource *tmp; | |
92c7e002 | 671 | |
f1b82746 | 672 | list_for_each_entry(tmp, &clocksource_list, list) |
92c7e002 | 673 | /* Keep track of the place, where to insert */ |
f1b82746 MS |
674 | if (tmp->rating >= cs->rating) |
675 | entry = &tmp->list; | |
676 | list_add(&cs->list, entry); | |
734efb46 JS |
677 | } |
678 | ||
d7e81c26 | 679 | /** |
852db46d | 680 | * __clocksource_updatefreq_scale - Used update clocksource with new freq |
b1b73d09 | 681 | * @cs: clocksource to be registered |
d7e81c26 JS |
682 | * @scale: Scale factor multiplied against freq to get clocksource hz |
683 | * @freq: clocksource frequency (cycles per second) divided by scale | |
684 | * | |
852db46d | 685 | * This should only be called from the clocksource->enable() method. |
d7e81c26 JS |
686 | * |
687 | * This *SHOULD NOT* be called directly! Please use the | |
852db46d | 688 | * clocksource_updatefreq_hz() or clocksource_updatefreq_khz helper functions. |
d7e81c26 | 689 | */ |
852db46d | 690 | void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq) |
d7e81c26 | 691 | { |
c0e299b1 | 692 | u64 sec; |
d7e81c26 | 693 | /* |
724ed53e TG |
694 | * Calc the maximum number of seconds which we can run before |
695 | * wrapping around. For clocksources which have a mask > 32bit | |
696 | * we need to limit the max sleep time to have a good | |
697 | * conversion precision. 10 minutes is still a reasonable | |
698 | * amount. That results in a shift value of 24 for a | |
699 | * clocksource with mask >= 40bit and f >= 4GHz. That maps to | |
700 | * ~ 0.06ppm granularity for NTP. We apply the same 12.5% | |
701 | * margin as we do in clocksource_max_deferment() | |
d7e81c26 | 702 | */ |
b1f91966 | 703 | sec = (cs->mask - (cs->mask >> 3)); |
724ed53e TG |
704 | do_div(sec, freq); |
705 | do_div(sec, scale); | |
706 | if (!sec) | |
707 | sec = 1; | |
708 | else if (sec > 600 && cs->mask > UINT_MAX) | |
709 | sec = 600; | |
710 | ||
d7e81c26 | 711 | clocks_calc_mult_shift(&cs->mult, &cs->shift, freq, |
724ed53e | 712 | NSEC_PER_SEC / scale, sec * scale); |
d65670a7 JS |
713 | |
714 | /* | |
715 | * for clocksources that have large mults, to avoid overflow. | |
716 | * Since mult may be adjusted by ntp, add an safety extra margin | |
717 | * | |
718 | */ | |
719 | cs->maxadj = clocksource_max_adjustment(cs); | |
720 | while ((cs->mult + cs->maxadj < cs->mult) | |
721 | || (cs->mult - cs->maxadj > cs->mult)) { | |
722 | cs->mult >>= 1; | |
723 | cs->shift--; | |
724 | cs->maxadj = clocksource_max_adjustment(cs); | |
725 | } | |
726 | ||
d7e81c26 | 727 | cs->max_idle_ns = clocksource_max_deferment(cs); |
852db46d JS |
728 | } |
729 | EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale); | |
730 | ||
731 | /** | |
732 | * __clocksource_register_scale - Used to install new clocksources | |
b1b73d09 | 733 | * @cs: clocksource to be registered |
852db46d JS |
734 | * @scale: Scale factor multiplied against freq to get clocksource hz |
735 | * @freq: clocksource frequency (cycles per second) divided by scale | |
736 | * | |
737 | * Returns -EBUSY if registration fails, zero otherwise. | |
738 | * | |
739 | * This *SHOULD NOT* be called directly! Please use the | |
740 | * clocksource_register_hz() or clocksource_register_khz helper functions. | |
741 | */ | |
742 | int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) | |
743 | { | |
744 | ||
b595076a | 745 | /* Initialize mult/shift and max_idle_ns */ |
852db46d | 746 | __clocksource_updatefreq_scale(cs, scale, freq); |
d7e81c26 | 747 | |
852db46d | 748 | /* Add clocksource to the clcoksource list */ |
d7e81c26 JS |
749 | mutex_lock(&clocksource_mutex); |
750 | clocksource_enqueue(cs); | |
d7e81c26 | 751 | clocksource_enqueue_watchdog(cs); |
e05b2efb | 752 | clocksource_select(); |
d7e81c26 JS |
753 | mutex_unlock(&clocksource_mutex); |
754 | return 0; | |
755 | } | |
756 | EXPORT_SYMBOL_GPL(__clocksource_register_scale); | |
757 | ||
758 | ||
734efb46 | 759 | /** |
a2752549 | 760 | * clocksource_register - Used to install new clocksources |
b1b73d09 | 761 | * @cs: clocksource to be registered |
734efb46 JS |
762 | * |
763 | * Returns -EBUSY if registration fails, zero otherwise. | |
764 | */ | |
f1b82746 | 765 | int clocksource_register(struct clocksource *cs) |
734efb46 | 766 | { |
d65670a7 JS |
767 | /* calculate max adjustment for given mult/shift */ |
768 | cs->maxadj = clocksource_max_adjustment(cs); | |
769 | WARN_ONCE(cs->mult + cs->maxadj < cs->mult, | |
770 | "Clocksource %s might overflow on 11%% adjustment\n", | |
771 | cs->name); | |
772 | ||
98962465 JH |
773 | /* calculate max idle time permitted for this clocksource */ |
774 | cs->max_idle_ns = clocksource_max_deferment(cs); | |
775 | ||
75c5158f | 776 | mutex_lock(&clocksource_mutex); |
f1b82746 | 777 | clocksource_enqueue(cs); |
fb63a0eb | 778 | clocksource_enqueue_watchdog(cs); |
e05b2efb | 779 | clocksource_select(); |
75c5158f | 780 | mutex_unlock(&clocksource_mutex); |
f1b82746 | 781 | return 0; |
734efb46 | 782 | } |
a2752549 | 783 | EXPORT_SYMBOL(clocksource_register); |
734efb46 | 784 | |
d0981a1b TG |
785 | static void __clocksource_change_rating(struct clocksource *cs, int rating) |
786 | { | |
787 | list_del(&cs->list); | |
788 | cs->rating = rating; | |
789 | clocksource_enqueue(cs); | |
790 | clocksource_select(); | |
791 | } | |
792 | ||
734efb46 | 793 | /** |
92c7e002 | 794 | * clocksource_change_rating - Change the rating of a registered clocksource |
b1b73d09 KK |
795 | * @cs: clocksource to be changed |
796 | * @rating: new rating | |
734efb46 | 797 | */ |
92c7e002 | 798 | void clocksource_change_rating(struct clocksource *cs, int rating) |
734efb46 | 799 | { |
75c5158f | 800 | mutex_lock(&clocksource_mutex); |
d0981a1b | 801 | __clocksource_change_rating(cs, rating); |
75c5158f | 802 | mutex_unlock(&clocksource_mutex); |
734efb46 | 803 | } |
fb63a0eb | 804 | EXPORT_SYMBOL(clocksource_change_rating); |
734efb46 | 805 | |
7eaeb343 TG |
806 | /* |
807 | * Unbind clocksource @cs. Called with clocksource_mutex held | |
808 | */ | |
809 | static int clocksource_unbind(struct clocksource *cs) | |
810 | { | |
811 | /* | |
812 | * I really can't convince myself to support this on hardware | |
813 | * designed by lobotomized monkeys. | |
814 | */ | |
815 | if (clocksource_is_watchdog(cs)) | |
816 | return -EBUSY; | |
817 | ||
818 | if (cs == curr_clocksource) { | |
819 | /* Select and try to install a replacement clock source */ | |
820 | clocksource_select_fallback(); | |
821 | if (curr_clocksource == cs) | |
822 | return -EBUSY; | |
823 | } | |
824 | clocksource_dequeue_watchdog(cs); | |
825 | list_del_init(&cs->list); | |
826 | return 0; | |
827 | } | |
828 | ||
4713e22c TG |
829 | /** |
830 | * clocksource_unregister - remove a registered clocksource | |
b1b73d09 | 831 | * @cs: clocksource to be unregistered |
4713e22c | 832 | */ |
a89c7edb | 833 | int clocksource_unregister(struct clocksource *cs) |
4713e22c | 834 | { |
a89c7edb TG |
835 | int ret = 0; |
836 | ||
75c5158f | 837 | mutex_lock(&clocksource_mutex); |
a89c7edb TG |
838 | if (!list_empty(&cs->list)) |
839 | ret = clocksource_unbind(cs); | |
75c5158f | 840 | mutex_unlock(&clocksource_mutex); |
a89c7edb | 841 | return ret; |
4713e22c | 842 | } |
fb63a0eb | 843 | EXPORT_SYMBOL(clocksource_unregister); |
4713e22c | 844 | |
2b013700 | 845 | #ifdef CONFIG_SYSFS |
734efb46 JS |
846 | /** |
847 | * sysfs_show_current_clocksources - sysfs interface for current clocksource | |
848 | * @dev: unused | |
b1b73d09 | 849 | * @attr: unused |
734efb46 JS |
850 | * @buf: char buffer to be filled with clocksource list |
851 | * | |
852 | * Provides sysfs interface for listing current clocksource. | |
853 | */ | |
854 | static ssize_t | |
d369a5d8 KS |
855 | sysfs_show_current_clocksources(struct device *dev, |
856 | struct device_attribute *attr, char *buf) | |
734efb46 | 857 | { |
5e2cb101 | 858 | ssize_t count = 0; |
734efb46 | 859 | |
75c5158f | 860 | mutex_lock(&clocksource_mutex); |
5e2cb101 | 861 | count = snprintf(buf, PAGE_SIZE, "%s\n", curr_clocksource->name); |
75c5158f | 862 | mutex_unlock(&clocksource_mutex); |
734efb46 | 863 | |
5e2cb101 | 864 | return count; |
734efb46 JS |
865 | } |
866 | ||
29b54078 TG |
867 | static size_t clocksource_get_uname(const char *buf, char *dst, size_t cnt) |
868 | { | |
869 | size_t ret = cnt; | |
870 | ||
871 | /* strings from sysfs write are not 0 terminated! */ | |
872 | if (!cnt || cnt >= CS_NAME_LEN) | |
873 | return -EINVAL; | |
874 | ||
875 | /* strip of \n: */ | |
876 | if (buf[cnt-1] == '\n') | |
877 | cnt--; | |
878 | if (cnt > 0) | |
879 | memcpy(dst, buf, cnt); | |
880 | dst[cnt] = 0; | |
881 | return ret; | |
882 | } | |
883 | ||
734efb46 JS |
884 | /** |
885 | * sysfs_override_clocksource - interface for manually overriding clocksource | |
886 | * @dev: unused | |
b1b73d09 | 887 | * @attr: unused |
734efb46 JS |
888 | * @buf: name of override clocksource |
889 | * @count: length of buffer | |
890 | * | |
891 | * Takes input from sysfs interface for manually overriding the default | |
b71a8eb0 | 892 | * clocksource selection. |
734efb46 | 893 | */ |
d369a5d8 KS |
894 | static ssize_t sysfs_override_clocksource(struct device *dev, |
895 | struct device_attribute *attr, | |
734efb46 JS |
896 | const char *buf, size_t count) |
897 | { | |
29b54078 | 898 | size_t ret; |
734efb46 | 899 | |
75c5158f | 900 | mutex_lock(&clocksource_mutex); |
734efb46 | 901 | |
29b54078 TG |
902 | ret = clocksource_get_uname(buf, override_name, count); |
903 | if (ret >= 0) | |
904 | clocksource_select(); | |
734efb46 | 905 | |
75c5158f | 906 | mutex_unlock(&clocksource_mutex); |
734efb46 JS |
907 | |
908 | return ret; | |
909 | } | |
910 | ||
7eaeb343 TG |
911 | /** |
912 | * sysfs_unbind_current_clocksource - interface for manually unbinding clocksource | |
913 | * @dev: unused | |
914 | * @attr: unused | |
915 | * @buf: unused | |
916 | * @count: length of buffer | |
917 | * | |
918 | * Takes input from sysfs interface for manually unbinding a clocksource. | |
919 | */ | |
920 | static ssize_t sysfs_unbind_clocksource(struct device *dev, | |
921 | struct device_attribute *attr, | |
922 | const char *buf, size_t count) | |
923 | { | |
924 | struct clocksource *cs; | |
925 | char name[CS_NAME_LEN]; | |
926 | size_t ret; | |
927 | ||
928 | ret = clocksource_get_uname(buf, name, count); | |
929 | if (ret < 0) | |
930 | return ret; | |
931 | ||
932 | ret = -ENODEV; | |
933 | mutex_lock(&clocksource_mutex); | |
934 | list_for_each_entry(cs, &clocksource_list, list) { | |
935 | if (strcmp(cs->name, name)) | |
936 | continue; | |
937 | ret = clocksource_unbind(cs); | |
938 | break; | |
939 | } | |
940 | mutex_unlock(&clocksource_mutex); | |
941 | ||
942 | return ret ? ret : count; | |
943 | } | |
944 | ||
734efb46 JS |
945 | /** |
946 | * sysfs_show_available_clocksources - sysfs interface for listing clocksource | |
947 | * @dev: unused | |
b1b73d09 | 948 | * @attr: unused |
734efb46 JS |
949 | * @buf: char buffer to be filled with clocksource list |
950 | * | |
951 | * Provides sysfs interface for listing registered clocksources | |
952 | */ | |
953 | static ssize_t | |
d369a5d8 KS |
954 | sysfs_show_available_clocksources(struct device *dev, |
955 | struct device_attribute *attr, | |
4a0b2b4d | 956 | char *buf) |
734efb46 | 957 | { |
2e197586 | 958 | struct clocksource *src; |
5e2cb101 | 959 | ssize_t count = 0; |
734efb46 | 960 | |
75c5158f | 961 | mutex_lock(&clocksource_mutex); |
2e197586 | 962 | list_for_each_entry(src, &clocksource_list, list) { |
cd6d95d8 TG |
963 | /* |
964 | * Don't show non-HRES clocksource if the tick code is | |
965 | * in one shot mode (highres=on or nohz=on) | |
966 | */ | |
967 | if (!tick_oneshot_mode_active() || | |
968 | (src->flags & CLOCK_SOURCE_VALID_FOR_HRES)) | |
3f68535a | 969 | count += snprintf(buf + count, |
5e2cb101 MX |
970 | max((ssize_t)PAGE_SIZE - count, (ssize_t)0), |
971 | "%s ", src->name); | |
734efb46 | 972 | } |
75c5158f | 973 | mutex_unlock(&clocksource_mutex); |
734efb46 | 974 | |
5e2cb101 MX |
975 | count += snprintf(buf + count, |
976 | max((ssize_t)PAGE_SIZE - count, (ssize_t)0), "\n"); | |
734efb46 | 977 | |
5e2cb101 | 978 | return count; |
734efb46 JS |
979 | } |
980 | ||
981 | /* | |
982 | * Sysfs setup bits: | |
983 | */ | |
d369a5d8 | 984 | static DEVICE_ATTR(current_clocksource, 0644, sysfs_show_current_clocksources, |
f5f1a24a | 985 | sysfs_override_clocksource); |
734efb46 | 986 | |
7eaeb343 TG |
987 | static DEVICE_ATTR(unbind_clocksource, 0200, NULL, sysfs_unbind_clocksource); |
988 | ||
d369a5d8 | 989 | static DEVICE_ATTR(available_clocksource, 0444, |
f5f1a24a | 990 | sysfs_show_available_clocksources, NULL); |
734efb46 | 991 | |
d369a5d8 | 992 | static struct bus_type clocksource_subsys = { |
af5ca3f4 | 993 | .name = "clocksource", |
d369a5d8 | 994 | .dev_name = "clocksource", |
734efb46 JS |
995 | }; |
996 | ||
d369a5d8 | 997 | static struct device device_clocksource = { |
734efb46 | 998 | .id = 0, |
d369a5d8 | 999 | .bus = &clocksource_subsys, |
734efb46 JS |
1000 | }; |
1001 | ||
ad596171 | 1002 | static int __init init_clocksource_sysfs(void) |
734efb46 | 1003 | { |
d369a5d8 | 1004 | int error = subsys_system_register(&clocksource_subsys, NULL); |
734efb46 JS |
1005 | |
1006 | if (!error) | |
d369a5d8 | 1007 | error = device_register(&device_clocksource); |
734efb46 | 1008 | if (!error) |
d369a5d8 | 1009 | error = device_create_file( |
734efb46 | 1010 | &device_clocksource, |
d369a5d8 | 1011 | &dev_attr_current_clocksource); |
7eaeb343 TG |
1012 | if (!error) |
1013 | error = device_create_file(&device_clocksource, | |
1014 | &dev_attr_unbind_clocksource); | |
734efb46 | 1015 | if (!error) |
d369a5d8 | 1016 | error = device_create_file( |
734efb46 | 1017 | &device_clocksource, |
d369a5d8 | 1018 | &dev_attr_available_clocksource); |
734efb46 JS |
1019 | return error; |
1020 | } | |
1021 | ||
1022 | device_initcall(init_clocksource_sysfs); | |
2b013700 | 1023 | #endif /* CONFIG_SYSFS */ |
734efb46 JS |
1024 | |
1025 | /** | |
1026 | * boot_override_clocksource - boot clock override | |
1027 | * @str: override name | |
1028 | * | |
1029 | * Takes a clocksource= boot argument and uses it | |
1030 | * as the clocksource override name. | |
1031 | */ | |
1032 | static int __init boot_override_clocksource(char* str) | |
1033 | { | |
75c5158f | 1034 | mutex_lock(&clocksource_mutex); |
734efb46 JS |
1035 | if (str) |
1036 | strlcpy(override_name, str, sizeof(override_name)); | |
75c5158f | 1037 | mutex_unlock(&clocksource_mutex); |
734efb46 JS |
1038 | return 1; |
1039 | } | |
1040 | ||
1041 | __setup("clocksource=", boot_override_clocksource); | |
1042 | ||
1043 | /** | |
1044 | * boot_override_clock - Compatibility layer for deprecated boot option | |
1045 | * @str: override name | |
1046 | * | |
1047 | * DEPRECATED! Takes a clock= boot argument and uses it | |
1048 | * as the clocksource override name | |
1049 | */ | |
1050 | static int __init boot_override_clock(char* str) | |
1051 | { | |
5d0cf410 JS |
1052 | if (!strcmp(str, "pmtmr")) { |
1053 | printk("Warning: clock=pmtmr is deprecated. " | |
1054 | "Use clocksource=acpi_pm.\n"); | |
1055 | return boot_override_clocksource("acpi_pm"); | |
1056 | } | |
1057 | printk("Warning! clock= boot option is deprecated. " | |
1058 | "Use clocksource=xyz\n"); | |
734efb46 JS |
1059 | return boot_override_clocksource(str); |
1060 | } | |
1061 | ||
1062 | __setup("clock=", boot_override_clock); |