Commit | Line | Data |
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734efb46 | 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 | 24 | */ |
25 | ||
26 | #include <linux/clocksource.h> | |
27 | #include <linux/sysdev.h> | |
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> |
734efb46 | 32 | |
a038a353 PO |
33 | void timecounter_init(struct timecounter *tc, |
34 | const struct cyclecounter *cc, | |
35 | u64 start_tstamp) | |
36 | { | |
37 | tc->cc = cc; | |
38 | tc->cycle_last = cc->read(cc); | |
39 | tc->nsec = start_tstamp; | |
40 | } | |
41 | EXPORT_SYMBOL(timecounter_init); | |
42 | ||
43 | /** | |
44 | * timecounter_read_delta - get nanoseconds since last call of this function | |
45 | * @tc: Pointer to time counter | |
46 | * | |
47 | * When the underlying cycle counter runs over, this will be handled | |
48 | * correctly as long as it does not run over more than once between | |
49 | * calls. | |
50 | * | |
51 | * The first call to this function for a new time counter initializes | |
52 | * the time tracking and returns an undefined result. | |
53 | */ | |
54 | static u64 timecounter_read_delta(struct timecounter *tc) | |
55 | { | |
56 | cycle_t cycle_now, cycle_delta; | |
57 | u64 ns_offset; | |
58 | ||
59 | /* read cycle counter: */ | |
60 | cycle_now = tc->cc->read(tc->cc); | |
61 | ||
62 | /* calculate the delta since the last timecounter_read_delta(): */ | |
63 | cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask; | |
64 | ||
65 | /* convert to nanoseconds: */ | |
66 | ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta); | |
67 | ||
68 | /* update time stamp of timecounter_read_delta() call: */ | |
69 | tc->cycle_last = cycle_now; | |
70 | ||
71 | return ns_offset; | |
72 | } | |
73 | ||
74 | u64 timecounter_read(struct timecounter *tc) | |
75 | { | |
76 | u64 nsec; | |
77 | ||
78 | /* increment time by nanoseconds since last call */ | |
79 | nsec = timecounter_read_delta(tc); | |
80 | nsec += tc->nsec; | |
81 | tc->nsec = nsec; | |
82 | ||
83 | return nsec; | |
84 | } | |
85 | EXPORT_SYMBOL(timecounter_read); | |
86 | ||
87 | u64 timecounter_cyc2time(struct timecounter *tc, | |
88 | cycle_t cycle_tstamp) | |
89 | { | |
90 | u64 cycle_delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask; | |
91 | u64 nsec; | |
92 | ||
93 | /* | |
94 | * Instead of always treating cycle_tstamp as more recent | |
95 | * than tc->cycle_last, detect when it is too far in the | |
96 | * future and treat it as old time stamp instead. | |
97 | */ | |
98 | if (cycle_delta > tc->cc->mask / 2) { | |
99 | cycle_delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask; | |
100 | nsec = tc->nsec - cyclecounter_cyc2ns(tc->cc, cycle_delta); | |
101 | } else { | |
102 | nsec = cyclecounter_cyc2ns(tc->cc, cycle_delta) + tc->nsec; | |
103 | } | |
104 | ||
105 | return nsec; | |
106 | } | |
107 | EXPORT_SYMBOL(timecounter_cyc2time); | |
108 | ||
734efb46 | 109 | /*[Clocksource internal variables]--------- |
110 | * curr_clocksource: | |
f1b82746 | 111 | * currently selected clocksource. |
734efb46 | 112 | * next_clocksource: |
113 | * pending next selected clocksource. | |
114 | * clocksource_list: | |
115 | * linked list with the registered clocksources | |
116 | * clocksource_lock: | |
117 | * protects manipulations to curr_clocksource and next_clocksource | |
118 | * and the clocksource_list | |
119 | * override_name: | |
120 | * Name of the user-specified clocksource. | |
121 | */ | |
f1b82746 | 122 | static struct clocksource *curr_clocksource; |
734efb46 | 123 | static struct clocksource *next_clocksource; |
124 | static LIST_HEAD(clocksource_list); | |
125 | static DEFINE_SPINLOCK(clocksource_lock); | |
126 | static char override_name[32]; | |
127 | static int finished_booting; | |
128 | ||
6bb74df4 | 129 | /* clocksource_done_booting - Called near the end of core bootup |
734efb46 | 130 | * |
6bb74df4 | 131 | * Hack to avoid lots of clocksource churn at boot time. |
132 | * We use fs_initcall because we want this to start before | |
133 | * device_initcall but after subsys_initcall. | |
734efb46 | 134 | */ |
ad596171 | 135 | static int __init clocksource_done_booting(void) |
734efb46 | 136 | { |
137 | finished_booting = 1; | |
138 | return 0; | |
139 | } | |
6bb74df4 | 140 | fs_initcall(clocksource_done_booting); |
734efb46 | 141 | |
5d8b34fd TG |
142 | #ifdef CONFIG_CLOCKSOURCE_WATCHDOG |
143 | static LIST_HEAD(watchdog_list); | |
144 | static struct clocksource *watchdog; | |
145 | static struct timer_list watchdog_timer; | |
146 | static DEFINE_SPINLOCK(watchdog_lock); | |
147 | static cycle_t watchdog_last; | |
8f89441b | 148 | static unsigned long watchdog_resumed; |
b52f52a0 | 149 | |
5d8b34fd | 150 | /* |
35c35d1a | 151 | * Interval: 0.5sec Threshold: 0.0625s |
5d8b34fd TG |
152 | */ |
153 | #define WATCHDOG_INTERVAL (HZ >> 1) | |
35c35d1a | 154 | #define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 4) |
5d8b34fd TG |
155 | |
156 | static void clocksource_ratewd(struct clocksource *cs, int64_t delta) | |
157 | { | |
35c35d1a | 158 | if (delta > -WATCHDOG_THRESHOLD && delta < WATCHDOG_THRESHOLD) |
5d8b34fd TG |
159 | return; |
160 | ||
161 | printk(KERN_WARNING "Clocksource %s unstable (delta = %Ld ns)\n", | |
162 | cs->name, delta); | |
163 | cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG); | |
164 | clocksource_change_rating(cs, 0); | |
5d8b34fd TG |
165 | list_del(&cs->wd_list); |
166 | } | |
167 | ||
168 | static void clocksource_watchdog(unsigned long data) | |
169 | { | |
170 | struct clocksource *cs, *tmp; | |
171 | cycle_t csnow, wdnow; | |
172 | int64_t wd_nsec, cs_nsec; | |
b52f52a0 | 173 | int resumed; |
5d8b34fd TG |
174 | |
175 | spin_lock(&watchdog_lock); | |
176 | ||
8f89441b | 177 | resumed = test_and_clear_bit(0, &watchdog_resumed); |
b52f52a0 | 178 | |
8e19608e | 179 | wdnow = watchdog->read(watchdog); |
5d8b34fd TG |
180 | wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask); |
181 | watchdog_last = wdnow; | |
182 | ||
183 | list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) { | |
8e19608e | 184 | csnow = cs->read(cs); |
b52f52a0 TG |
185 | |
186 | if (unlikely(resumed)) { | |
187 | cs->wd_last = csnow; | |
188 | continue; | |
189 | } | |
190 | ||
5d8b34fd TG |
191 | /* Initialized ? */ |
192 | if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) { | |
193 | if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) && | |
194 | (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) { | |
195 | cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; | |
79bf2bb3 TG |
196 | /* |
197 | * We just marked the clocksource as | |
198 | * highres-capable, notify the rest of the | |
199 | * system as well so that we transition | |
200 | * into high-res mode: | |
201 | */ | |
202 | tick_clock_notify(); | |
5d8b34fd TG |
203 | } |
204 | cs->flags |= CLOCK_SOURCE_WATCHDOG; | |
205 | cs->wd_last = csnow; | |
206 | } else { | |
207 | cs_nsec = cyc2ns(cs, (csnow - cs->wd_last) & cs->mask); | |
208 | cs->wd_last = csnow; | |
209 | /* Check the delta. Might remove from the list ! */ | |
210 | clocksource_ratewd(cs, cs_nsec - wd_nsec); | |
211 | } | |
212 | } | |
213 | ||
214 | if (!list_empty(&watchdog_list)) { | |
6993fc5b AK |
215 | /* |
216 | * Cycle through CPUs to check if the CPUs stay | |
217 | * synchronized to each other. | |
218 | */ | |
5db0e1e9 RR |
219 | int next_cpu = cpumask_next(raw_smp_processor_id(), |
220 | cpu_online_mask); | |
6993fc5b | 221 | |
cad0e458 | 222 | if (next_cpu >= nr_cpu_ids) |
6b954823 | 223 | next_cpu = cpumask_first(cpu_online_mask); |
6993fc5b AK |
224 | watchdog_timer.expires += WATCHDOG_INTERVAL; |
225 | add_timer_on(&watchdog_timer, next_cpu); | |
5d8b34fd TG |
226 | } |
227 | spin_unlock(&watchdog_lock); | |
228 | } | |
b52f52a0 TG |
229 | static void clocksource_resume_watchdog(void) |
230 | { | |
8f89441b | 231 | set_bit(0, &watchdog_resumed); |
b52f52a0 TG |
232 | } |
233 | ||
5d8b34fd TG |
234 | static void clocksource_check_watchdog(struct clocksource *cs) |
235 | { | |
236 | struct clocksource *cse; | |
237 | unsigned long flags; | |
238 | ||
239 | spin_lock_irqsave(&watchdog_lock, flags); | |
240 | if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) { | |
241 | int started = !list_empty(&watchdog_list); | |
242 | ||
243 | list_add(&cs->wd_list, &watchdog_list); | |
244 | if (!started && watchdog) { | |
8e19608e | 245 | watchdog_last = watchdog->read(watchdog); |
5d8b34fd | 246 | watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL; |
6993fc5b | 247 | add_timer_on(&watchdog_timer, |
6b954823 | 248 | cpumask_first(cpu_online_mask)); |
5d8b34fd | 249 | } |
948ac6d7 TG |
250 | } else { |
251 | if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) | |
5d8b34fd TG |
252 | cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; |
253 | ||
254 | if (!watchdog || cs->rating > watchdog->rating) { | |
255 | if (watchdog) | |
256 | del_timer(&watchdog_timer); | |
257 | watchdog = cs; | |
898a19de | 258 | init_timer(&watchdog_timer); |
5d8b34fd TG |
259 | watchdog_timer.function = clocksource_watchdog; |
260 | ||
261 | /* Reset watchdog cycles */ | |
262 | list_for_each_entry(cse, &watchdog_list, wd_list) | |
263 | cse->flags &= ~CLOCK_SOURCE_WATCHDOG; | |
264 | /* Start if list is not empty */ | |
265 | if (!list_empty(&watchdog_list)) { | |
8e19608e | 266 | watchdog_last = watchdog->read(watchdog); |
5d8b34fd TG |
267 | watchdog_timer.expires = |
268 | jiffies + WATCHDOG_INTERVAL; | |
6993fc5b | 269 | add_timer_on(&watchdog_timer, |
6b954823 | 270 | cpumask_first(cpu_online_mask)); |
5d8b34fd TG |
271 | } |
272 | } | |
273 | } | |
274 | spin_unlock_irqrestore(&watchdog_lock, flags); | |
275 | } | |
276 | #else | |
277 | static void clocksource_check_watchdog(struct clocksource *cs) | |
278 | { | |
279 | if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) | |
280 | cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; | |
281 | } | |
b52f52a0 TG |
282 | |
283 | static inline void clocksource_resume_watchdog(void) { } | |
5d8b34fd TG |
284 | #endif |
285 | ||
b52f52a0 TG |
286 | /** |
287 | * clocksource_resume - resume the clocksource(s) | |
288 | */ | |
289 | void clocksource_resume(void) | |
290 | { | |
2e197586 | 291 | struct clocksource *cs; |
b52f52a0 TG |
292 | unsigned long flags; |
293 | ||
294 | spin_lock_irqsave(&clocksource_lock, flags); | |
295 | ||
2e197586 | 296 | list_for_each_entry(cs, &clocksource_list, list) { |
b52f52a0 TG |
297 | if (cs->resume) |
298 | cs->resume(); | |
299 | } | |
300 | ||
301 | clocksource_resume_watchdog(); | |
302 | ||
303 | spin_unlock_irqrestore(&clocksource_lock, flags); | |
304 | } | |
305 | ||
7c3078b6 JW |
306 | /** |
307 | * clocksource_touch_watchdog - Update watchdog | |
308 | * | |
309 | * Update the watchdog after exception contexts such as kgdb so as not | |
310 | * to incorrectly trip the watchdog. | |
311 | * | |
312 | */ | |
313 | void clocksource_touch_watchdog(void) | |
314 | { | |
315 | clocksource_resume_watchdog(); | |
316 | } | |
317 | ||
f1b82746 | 318 | #ifdef CONFIG_GENERIC_TIME |
734efb46 | 319 | /** |
a2752549 | 320 | * clocksource_get_next - Returns the selected clocksource |
734efb46 | 321 | * |
322 | */ | |
a2752549 | 323 | struct clocksource *clocksource_get_next(void) |
734efb46 | 324 | { |
325 | unsigned long flags; | |
326 | ||
327 | spin_lock_irqsave(&clocksource_lock, flags); | |
328 | if (next_clocksource && finished_booting) { | |
329 | curr_clocksource = next_clocksource; | |
330 | next_clocksource = NULL; | |
331 | } | |
332 | spin_unlock_irqrestore(&clocksource_lock, flags); | |
333 | ||
334 | return curr_clocksource; | |
335 | } | |
336 | ||
337 | /** | |
f1b82746 | 338 | * clocksource_select - Select the best clocksource available |
734efb46 | 339 | * |
340 | * Private function. Must hold clocksource_lock when called. | |
341 | * | |
92c7e002 TG |
342 | * Select the clocksource with the best rating, or the clocksource, |
343 | * which is selected by userspace override. | |
734efb46 | 344 | */ |
f1b82746 | 345 | static void clocksource_select(void) |
734efb46 | 346 | { |
f1b82746 | 347 | struct clocksource *best, *cs; |
5d8b34fd | 348 | |
92c7e002 | 349 | if (list_empty(&clocksource_list)) |
f1b82746 MS |
350 | return; |
351 | /* First clocksource on the list has the best rating. */ | |
352 | best = list_first_entry(&clocksource_list, struct clocksource, list); | |
353 | /* Check for the override clocksource. */ | |
354 | list_for_each_entry(cs, &clocksource_list, list) { | |
355 | if (strcmp(cs->name, override_name) != 0) | |
356 | continue; | |
357 | /* | |
358 | * Check to make sure we don't switch to a non-highres | |
359 | * capable clocksource if the tick code is in oneshot | |
360 | * mode (highres or nohz) | |
361 | */ | |
362 | if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && | |
363 | tick_oneshot_mode_active()) { | |
364 | /* Override clocksource cannot be used. */ | |
365 | printk(KERN_WARNING "Override clocksource %s is not " | |
366 | "HRT compatible. Cannot switch while in " | |
367 | "HRT/NOHZ mode\n", cs->name); | |
368 | override_name[0] = 0; | |
369 | } else | |
370 | /* Override clocksource can be used. */ | |
371 | best = cs; | |
372 | break; | |
373 | } | |
374 | if (curr_clocksource != best) | |
375 | next_clocksource = best; | |
376 | } | |
734efb46 | 377 | |
f1b82746 | 378 | #else /* CONFIG_GENERIC_TIME */ |
734efb46 | 379 | |
f1b82746 | 380 | static void clocksource_select(void) { } |
5d8b34fd | 381 | |
f1b82746 | 382 | #endif |
734efb46 | 383 | |
92c7e002 TG |
384 | /* |
385 | * Enqueue the clocksource sorted by rating | |
734efb46 | 386 | */ |
f1b82746 | 387 | static void clocksource_enqueue(struct clocksource *cs) |
734efb46 | 388 | { |
f1b82746 MS |
389 | struct list_head *entry = &clocksource_list; |
390 | struct clocksource *tmp; | |
92c7e002 | 391 | |
f1b82746 | 392 | list_for_each_entry(tmp, &clocksource_list, list) |
92c7e002 | 393 | /* Keep track of the place, where to insert */ |
f1b82746 MS |
394 | if (tmp->rating >= cs->rating) |
395 | entry = &tmp->list; | |
396 | list_add(&cs->list, entry); | |
734efb46 | 397 | } |
398 | ||
399 | /** | |
a2752549 | 400 | * clocksource_register - Used to install new clocksources |
734efb46 | 401 | * @t: clocksource to be registered |
402 | * | |
403 | * Returns -EBUSY if registration fails, zero otherwise. | |
404 | */ | |
f1b82746 | 405 | int clocksource_register(struct clocksource *cs) |
734efb46 | 406 | { |
734efb46 | 407 | unsigned long flags; |
408 | ||
409 | spin_lock_irqsave(&clocksource_lock, flags); | |
f1b82746 MS |
410 | clocksource_enqueue(cs); |
411 | clocksource_select(); | |
734efb46 | 412 | spin_unlock_irqrestore(&clocksource_lock, flags); |
f1b82746 MS |
413 | clocksource_check_watchdog(cs); |
414 | return 0; | |
734efb46 | 415 | } |
a2752549 | 416 | EXPORT_SYMBOL(clocksource_register); |
734efb46 | 417 | |
418 | /** | |
92c7e002 | 419 | * clocksource_change_rating - Change the rating of a registered clocksource |
734efb46 | 420 | * |
734efb46 | 421 | */ |
92c7e002 | 422 | void clocksource_change_rating(struct clocksource *cs, int rating) |
734efb46 | 423 | { |
424 | unsigned long flags; | |
425 | ||
426 | spin_lock_irqsave(&clocksource_lock, flags); | |
92c7e002 | 427 | list_del(&cs->list); |
5d8b34fd | 428 | cs->rating = rating; |
92c7e002 | 429 | clocksource_enqueue(cs); |
f1b82746 | 430 | clocksource_select(); |
734efb46 | 431 | spin_unlock_irqrestore(&clocksource_lock, flags); |
432 | } | |
433 | ||
4713e22c TG |
434 | /** |
435 | * clocksource_unregister - remove a registered clocksource | |
436 | */ | |
437 | void clocksource_unregister(struct clocksource *cs) | |
438 | { | |
439 | unsigned long flags; | |
440 | ||
441 | spin_lock_irqsave(&clocksource_lock, flags); | |
442 | list_del(&cs->list); | |
f1b82746 | 443 | clocksource_select(); |
4713e22c TG |
444 | spin_unlock_irqrestore(&clocksource_lock, flags); |
445 | } | |
446 | ||
2b013700 | 447 | #ifdef CONFIG_SYSFS |
734efb46 | 448 | /** |
449 | * sysfs_show_current_clocksources - sysfs interface for current clocksource | |
450 | * @dev: unused | |
451 | * @buf: char buffer to be filled with clocksource list | |
452 | * | |
453 | * Provides sysfs interface for listing current clocksource. | |
454 | */ | |
455 | static ssize_t | |
4a0b2b4d AK |
456 | sysfs_show_current_clocksources(struct sys_device *dev, |
457 | struct sysdev_attribute *attr, char *buf) | |
734efb46 | 458 | { |
5e2cb101 | 459 | ssize_t count = 0; |
734efb46 | 460 | |
461 | spin_lock_irq(&clocksource_lock); | |
5e2cb101 | 462 | count = snprintf(buf, PAGE_SIZE, "%s\n", curr_clocksource->name); |
734efb46 | 463 | spin_unlock_irq(&clocksource_lock); |
464 | ||
5e2cb101 | 465 | return count; |
734efb46 | 466 | } |
467 | ||
468 | /** | |
469 | * sysfs_override_clocksource - interface for manually overriding clocksource | |
470 | * @dev: unused | |
471 | * @buf: name of override clocksource | |
472 | * @count: length of buffer | |
473 | * | |
474 | * Takes input from sysfs interface for manually overriding the default | |
475 | * clocksource selction. | |
476 | */ | |
477 | static ssize_t sysfs_override_clocksource(struct sys_device *dev, | |
4a0b2b4d | 478 | struct sysdev_attribute *attr, |
734efb46 | 479 | const char *buf, size_t count) |
480 | { | |
481 | size_t ret = count; | |
92c7e002 | 482 | |
734efb46 | 483 | /* strings from sysfs write are not 0 terminated! */ |
484 | if (count >= sizeof(override_name)) | |
485 | return -EINVAL; | |
486 | ||
487 | /* strip of \n: */ | |
488 | if (buf[count-1] == '\n') | |
489 | count--; | |
734efb46 | 490 | |
491 | spin_lock_irq(&clocksource_lock); | |
492 | ||
92c7e002 TG |
493 | if (count > 0) |
494 | memcpy(override_name, buf, count); | |
734efb46 | 495 | override_name[count] = 0; |
f1b82746 | 496 | clocksource_select(); |
734efb46 | 497 | |
498 | spin_unlock_irq(&clocksource_lock); | |
499 | ||
500 | return ret; | |
501 | } | |
502 | ||
503 | /** | |
504 | * sysfs_show_available_clocksources - sysfs interface for listing clocksource | |
505 | * @dev: unused | |
506 | * @buf: char buffer to be filled with clocksource list | |
507 | * | |
508 | * Provides sysfs interface for listing registered clocksources | |
509 | */ | |
510 | static ssize_t | |
4a0b2b4d AK |
511 | sysfs_show_available_clocksources(struct sys_device *dev, |
512 | struct sysdev_attribute *attr, | |
513 | char *buf) | |
734efb46 | 514 | { |
2e197586 | 515 | struct clocksource *src; |
5e2cb101 | 516 | ssize_t count = 0; |
734efb46 | 517 | |
518 | spin_lock_irq(&clocksource_lock); | |
2e197586 | 519 | list_for_each_entry(src, &clocksource_list, list) { |
cd6d95d8 TG |
520 | /* |
521 | * Don't show non-HRES clocksource if the tick code is | |
522 | * in one shot mode (highres=on or nohz=on) | |
523 | */ | |
524 | if (!tick_oneshot_mode_active() || | |
525 | (src->flags & CLOCK_SOURCE_VALID_FOR_HRES)) | |
3f68535a | 526 | count += snprintf(buf + count, |
5e2cb101 MX |
527 | max((ssize_t)PAGE_SIZE - count, (ssize_t)0), |
528 | "%s ", src->name); | |
734efb46 | 529 | } |
530 | spin_unlock_irq(&clocksource_lock); | |
531 | ||
5e2cb101 MX |
532 | count += snprintf(buf + count, |
533 | max((ssize_t)PAGE_SIZE - count, (ssize_t)0), "\n"); | |
734efb46 | 534 | |
5e2cb101 | 535 | return count; |
734efb46 | 536 | } |
537 | ||
538 | /* | |
539 | * Sysfs setup bits: | |
540 | */ | |
4f95f81a | 541 | static SYSDEV_ATTR(current_clocksource, 0644, sysfs_show_current_clocksources, |
f5f1a24a | 542 | sysfs_override_clocksource); |
734efb46 | 543 | |
4f95f81a | 544 | static SYSDEV_ATTR(available_clocksource, 0444, |
f5f1a24a | 545 | sysfs_show_available_clocksources, NULL); |
734efb46 | 546 | |
547 | static struct sysdev_class clocksource_sysclass = { | |
af5ca3f4 | 548 | .name = "clocksource", |
734efb46 | 549 | }; |
550 | ||
551 | static struct sys_device device_clocksource = { | |
552 | .id = 0, | |
553 | .cls = &clocksource_sysclass, | |
554 | }; | |
555 | ||
ad596171 | 556 | static int __init init_clocksource_sysfs(void) |
734efb46 | 557 | { |
558 | int error = sysdev_class_register(&clocksource_sysclass); | |
559 | ||
560 | if (!error) | |
561 | error = sysdev_register(&device_clocksource); | |
562 | if (!error) | |
563 | error = sysdev_create_file( | |
564 | &device_clocksource, | |
565 | &attr_current_clocksource); | |
566 | if (!error) | |
567 | error = sysdev_create_file( | |
568 | &device_clocksource, | |
569 | &attr_available_clocksource); | |
570 | return error; | |
571 | } | |
572 | ||
573 | device_initcall(init_clocksource_sysfs); | |
2b013700 | 574 | #endif /* CONFIG_SYSFS */ |
734efb46 | 575 | |
576 | /** | |
577 | * boot_override_clocksource - boot clock override | |
578 | * @str: override name | |
579 | * | |
580 | * Takes a clocksource= boot argument and uses it | |
581 | * as the clocksource override name. | |
582 | */ | |
583 | static int __init boot_override_clocksource(char* str) | |
584 | { | |
585 | unsigned long flags; | |
586 | spin_lock_irqsave(&clocksource_lock, flags); | |
587 | if (str) | |
588 | strlcpy(override_name, str, sizeof(override_name)); | |
589 | spin_unlock_irqrestore(&clocksource_lock, flags); | |
590 | return 1; | |
591 | } | |
592 | ||
593 | __setup("clocksource=", boot_override_clocksource); | |
594 | ||
595 | /** | |
596 | * boot_override_clock - Compatibility layer for deprecated boot option | |
597 | * @str: override name | |
598 | * | |
599 | * DEPRECATED! Takes a clock= boot argument and uses it | |
600 | * as the clocksource override name | |
601 | */ | |
602 | static int __init boot_override_clock(char* str) | |
603 | { | |
5d0cf410 | 604 | if (!strcmp(str, "pmtmr")) { |
605 | printk("Warning: clock=pmtmr is deprecated. " | |
606 | "Use clocksource=acpi_pm.\n"); | |
607 | return boot_override_clocksource("acpi_pm"); | |
608 | } | |
609 | printk("Warning! clock= boot option is deprecated. " | |
610 | "Use clocksource=xyz\n"); | |
734efb46 | 611 | return boot_override_clocksource(str); |
612 | } | |
613 | ||
614 | __setup("clock=", boot_override_clock); |