john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 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 |
| 24 | * o get rid of clocksource_jiffies extern |
| 25 | */ |
| 26 | |
| 27 | #include <linux/clocksource.h> |
| 28 | #include <linux/sysdev.h> |
| 29 | #include <linux/init.h> |
| 30 | #include <linux/module.h> |
Mathieu Desnoyers | dc29a36 | 2007-02-10 01:43:43 -0800 | [diff] [blame] | 31 | #include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */ |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 32 | #include <linux/tick.h> |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 33 | |
| 34 | /* XXX - Would like a better way for initializing curr_clocksource */ |
| 35 | extern struct clocksource clocksource_jiffies; |
| 36 | |
| 37 | /*[Clocksource internal variables]--------- |
| 38 | * curr_clocksource: |
| 39 | * currently selected clocksource. Initialized to clocksource_jiffies. |
| 40 | * next_clocksource: |
| 41 | * pending next selected clocksource. |
| 42 | * clocksource_list: |
| 43 | * linked list with the registered clocksources |
| 44 | * clocksource_lock: |
| 45 | * protects manipulations to curr_clocksource and next_clocksource |
| 46 | * and the clocksource_list |
| 47 | * override_name: |
| 48 | * Name of the user-specified clocksource. |
| 49 | */ |
| 50 | static struct clocksource *curr_clocksource = &clocksource_jiffies; |
| 51 | static struct clocksource *next_clocksource; |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 52 | static struct clocksource *clocksource_override; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 53 | static LIST_HEAD(clocksource_list); |
| 54 | static DEFINE_SPINLOCK(clocksource_lock); |
| 55 | static char override_name[32]; |
| 56 | static int finished_booting; |
| 57 | |
john stultz | 6bb74df | 2007-03-05 00:30:50 -0800 | [diff] [blame] | 58 | /* clocksource_done_booting - Called near the end of core bootup |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 59 | * |
john stultz | 6bb74df | 2007-03-05 00:30:50 -0800 | [diff] [blame] | 60 | * Hack to avoid lots of clocksource churn at boot time. |
| 61 | * We use fs_initcall because we want this to start before |
| 62 | * device_initcall but after subsys_initcall. |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 63 | */ |
john stultz | ad59617 | 2006-06-26 00:25:06 -0700 | [diff] [blame] | 64 | static int __init clocksource_done_booting(void) |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 65 | { |
| 66 | finished_booting = 1; |
| 67 | return 0; |
| 68 | } |
john stultz | 6bb74df | 2007-03-05 00:30:50 -0800 | [diff] [blame] | 69 | fs_initcall(clocksource_done_booting); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 70 | |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 71 | #ifdef CONFIG_CLOCKSOURCE_WATCHDOG |
| 72 | static LIST_HEAD(watchdog_list); |
| 73 | static struct clocksource *watchdog; |
| 74 | static struct timer_list watchdog_timer; |
| 75 | static DEFINE_SPINLOCK(watchdog_lock); |
| 76 | static cycle_t watchdog_last; |
Thomas Gleixner | 8f89441 | 2007-05-15 01:41:32 -0700 | [diff] [blame] | 77 | static unsigned long watchdog_resumed; |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 78 | |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 79 | /* |
Daniel Walker | 35c35d1 | 2007-05-09 02:33:40 -0700 | [diff] [blame] | 80 | * Interval: 0.5sec Threshold: 0.0625s |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 81 | */ |
| 82 | #define WATCHDOG_INTERVAL (HZ >> 1) |
Daniel Walker | 35c35d1 | 2007-05-09 02:33:40 -0700 | [diff] [blame] | 83 | #define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 4) |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 84 | |
| 85 | static void clocksource_ratewd(struct clocksource *cs, int64_t delta) |
| 86 | { |
Daniel Walker | 35c35d1 | 2007-05-09 02:33:40 -0700 | [diff] [blame] | 87 | if (delta > -WATCHDOG_THRESHOLD && delta < WATCHDOG_THRESHOLD) |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 88 | return; |
| 89 | |
| 90 | printk(KERN_WARNING "Clocksource %s unstable (delta = %Ld ns)\n", |
| 91 | cs->name, delta); |
| 92 | cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG); |
| 93 | clocksource_change_rating(cs, 0); |
| 94 | cs->flags &= ~CLOCK_SOURCE_WATCHDOG; |
| 95 | list_del(&cs->wd_list); |
| 96 | } |
| 97 | |
| 98 | static void clocksource_watchdog(unsigned long data) |
| 99 | { |
| 100 | struct clocksource *cs, *tmp; |
| 101 | cycle_t csnow, wdnow; |
| 102 | int64_t wd_nsec, cs_nsec; |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 103 | int resumed; |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 104 | |
| 105 | spin_lock(&watchdog_lock); |
| 106 | |
Thomas Gleixner | 8f89441 | 2007-05-15 01:41:32 -0700 | [diff] [blame] | 107 | resumed = test_and_clear_bit(0, &watchdog_resumed); |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 108 | |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 109 | wdnow = watchdog->read(); |
| 110 | wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask); |
| 111 | watchdog_last = wdnow; |
| 112 | |
| 113 | list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) { |
| 114 | csnow = cs->read(); |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 115 | |
| 116 | if (unlikely(resumed)) { |
| 117 | cs->wd_last = csnow; |
| 118 | continue; |
| 119 | } |
| 120 | |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 121 | /* Initialized ? */ |
| 122 | if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) { |
| 123 | if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) && |
| 124 | (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) { |
| 125 | cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 126 | /* |
| 127 | * We just marked the clocksource as |
| 128 | * highres-capable, notify the rest of the |
| 129 | * system as well so that we transition |
| 130 | * into high-res mode: |
| 131 | */ |
| 132 | tick_clock_notify(); |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 133 | } |
| 134 | cs->flags |= CLOCK_SOURCE_WATCHDOG; |
| 135 | cs->wd_last = csnow; |
| 136 | } else { |
| 137 | cs_nsec = cyc2ns(cs, (csnow - cs->wd_last) & cs->mask); |
| 138 | cs->wd_last = csnow; |
| 139 | /* Check the delta. Might remove from the list ! */ |
| 140 | clocksource_ratewd(cs, cs_nsec - wd_nsec); |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | if (!list_empty(&watchdog_list)) { |
| 145 | __mod_timer(&watchdog_timer, |
| 146 | watchdog_timer.expires + WATCHDOG_INTERVAL); |
| 147 | } |
| 148 | spin_unlock(&watchdog_lock); |
| 149 | } |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 150 | static void clocksource_resume_watchdog(void) |
| 151 | { |
Thomas Gleixner | 8f89441 | 2007-05-15 01:41:32 -0700 | [diff] [blame] | 152 | set_bit(0, &watchdog_resumed); |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 153 | } |
| 154 | |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 155 | static void clocksource_check_watchdog(struct clocksource *cs) |
| 156 | { |
| 157 | struct clocksource *cse; |
| 158 | unsigned long flags; |
| 159 | |
| 160 | spin_lock_irqsave(&watchdog_lock, flags); |
| 161 | if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) { |
| 162 | int started = !list_empty(&watchdog_list); |
| 163 | |
| 164 | list_add(&cs->wd_list, &watchdog_list); |
| 165 | if (!started && watchdog) { |
| 166 | watchdog_last = watchdog->read(); |
| 167 | watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL; |
| 168 | add_timer(&watchdog_timer); |
| 169 | } |
Thomas Gleixner | 948ac6d | 2007-03-25 14:42:51 +0200 | [diff] [blame] | 170 | } else { |
| 171 | if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 172 | cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; |
| 173 | |
| 174 | if (!watchdog || cs->rating > watchdog->rating) { |
| 175 | if (watchdog) |
| 176 | del_timer(&watchdog_timer); |
| 177 | watchdog = cs; |
| 178 | init_timer(&watchdog_timer); |
| 179 | watchdog_timer.function = clocksource_watchdog; |
| 180 | |
| 181 | /* Reset watchdog cycles */ |
| 182 | list_for_each_entry(cse, &watchdog_list, wd_list) |
| 183 | cse->flags &= ~CLOCK_SOURCE_WATCHDOG; |
| 184 | /* Start if list is not empty */ |
| 185 | if (!list_empty(&watchdog_list)) { |
| 186 | watchdog_last = watchdog->read(); |
| 187 | watchdog_timer.expires = |
| 188 | jiffies + WATCHDOG_INTERVAL; |
| 189 | add_timer(&watchdog_timer); |
| 190 | } |
| 191 | } |
| 192 | } |
| 193 | spin_unlock_irqrestore(&watchdog_lock, flags); |
| 194 | } |
| 195 | #else |
| 196 | static void clocksource_check_watchdog(struct clocksource *cs) |
| 197 | { |
| 198 | if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) |
| 199 | cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; |
| 200 | } |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 201 | |
| 202 | static inline void clocksource_resume_watchdog(void) { } |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 203 | #endif |
| 204 | |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 205 | /** |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 206 | * clocksource_resume - resume the clocksource(s) |
| 207 | */ |
| 208 | void clocksource_resume(void) |
| 209 | { |
Matthias Kaehlcke | 2e19758 | 2007-10-18 23:39:58 -0700 | [diff] [blame^] | 210 | struct clocksource *cs; |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 211 | unsigned long flags; |
| 212 | |
| 213 | spin_lock_irqsave(&clocksource_lock, flags); |
| 214 | |
Matthias Kaehlcke | 2e19758 | 2007-10-18 23:39:58 -0700 | [diff] [blame^] | 215 | list_for_each_entry(cs, &clocksource_list, list) { |
Thomas Gleixner | b52f52a | 2007-05-09 02:35:15 -0700 | [diff] [blame] | 216 | if (cs->resume) |
| 217 | cs->resume(); |
| 218 | } |
| 219 | |
| 220 | clocksource_resume_watchdog(); |
| 221 | |
| 222 | spin_unlock_irqrestore(&clocksource_lock, flags); |
| 223 | } |
| 224 | |
| 225 | /** |
john stultz | a275254 | 2006-06-26 00:25:14 -0700 | [diff] [blame] | 226 | * clocksource_get_next - Returns the selected clocksource |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 227 | * |
| 228 | */ |
john stultz | a275254 | 2006-06-26 00:25:14 -0700 | [diff] [blame] | 229 | struct clocksource *clocksource_get_next(void) |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 230 | { |
| 231 | unsigned long flags; |
| 232 | |
| 233 | spin_lock_irqsave(&clocksource_lock, flags); |
| 234 | if (next_clocksource && finished_booting) { |
| 235 | curr_clocksource = next_clocksource; |
| 236 | next_clocksource = NULL; |
| 237 | } |
| 238 | spin_unlock_irqrestore(&clocksource_lock, flags); |
| 239 | |
| 240 | return curr_clocksource; |
| 241 | } |
| 242 | |
| 243 | /** |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 244 | * select_clocksource - Selects the best registered clocksource. |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 245 | * |
| 246 | * Private function. Must hold clocksource_lock when called. |
| 247 | * |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 248 | * Select the clocksource with the best rating, or the clocksource, |
| 249 | * which is selected by userspace override. |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 250 | */ |
| 251 | static struct clocksource *select_clocksource(void) |
| 252 | { |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 253 | struct clocksource *next; |
| 254 | |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 255 | if (list_empty(&clocksource_list)) |
| 256 | return NULL; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 257 | |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 258 | if (clocksource_override) |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 259 | next = clocksource_override; |
| 260 | else |
| 261 | next = list_entry(clocksource_list.next, struct clocksource, |
| 262 | list); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 263 | |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 264 | if (next == curr_clocksource) |
| 265 | return NULL; |
| 266 | |
| 267 | return next; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 268 | } |
| 269 | |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 270 | /* |
| 271 | * Enqueue the clocksource sorted by rating |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 272 | */ |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 273 | static int clocksource_enqueue(struct clocksource *c) |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 274 | { |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 275 | struct list_head *tmp, *entry = &clocksource_list; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 276 | |
| 277 | list_for_each(tmp, &clocksource_list) { |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 278 | struct clocksource *cs; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 279 | |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 280 | cs = list_entry(tmp, struct clocksource, list); |
| 281 | if (cs == c) |
| 282 | return -EBUSY; |
| 283 | /* Keep track of the place, where to insert */ |
| 284 | if (cs->rating >= c->rating) |
| 285 | entry = tmp; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 286 | } |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 287 | list_add(&c->list, entry); |
| 288 | |
| 289 | if (strlen(c->name) == strlen(override_name) && |
| 290 | !strcmp(c->name, override_name)) |
| 291 | clocksource_override = c; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 292 | |
| 293 | return 0; |
| 294 | } |
| 295 | |
| 296 | /** |
john stultz | a275254 | 2006-06-26 00:25:14 -0700 | [diff] [blame] | 297 | * clocksource_register - Used to install new clocksources |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 298 | * @t: clocksource to be registered |
| 299 | * |
| 300 | * Returns -EBUSY if registration fails, zero otherwise. |
| 301 | */ |
john stultz | a275254 | 2006-06-26 00:25:14 -0700 | [diff] [blame] | 302 | int clocksource_register(struct clocksource *c) |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 303 | { |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 304 | unsigned long flags; |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 305 | int ret; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 306 | |
| 307 | spin_lock_irqsave(&clocksource_lock, flags); |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 308 | ret = clocksource_enqueue(c); |
| 309 | if (!ret) |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 310 | next_clocksource = select_clocksource(); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 311 | spin_unlock_irqrestore(&clocksource_lock, flags); |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 312 | if (!ret) |
| 313 | clocksource_check_watchdog(c); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 314 | return ret; |
| 315 | } |
john stultz | a275254 | 2006-06-26 00:25:14 -0700 | [diff] [blame] | 316 | EXPORT_SYMBOL(clocksource_register); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 317 | |
| 318 | /** |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 319 | * clocksource_change_rating - Change the rating of a registered clocksource |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 320 | * |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 321 | */ |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 322 | void clocksource_change_rating(struct clocksource *cs, int rating) |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 323 | { |
| 324 | unsigned long flags; |
| 325 | |
| 326 | spin_lock_irqsave(&clocksource_lock, flags); |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 327 | list_del(&cs->list); |
Thomas Gleixner | 5d8b34f | 2007-02-16 01:27:43 -0800 | [diff] [blame] | 328 | cs->rating = rating; |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 329 | clocksource_enqueue(cs); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 330 | next_clocksource = select_clocksource(); |
| 331 | spin_unlock_irqrestore(&clocksource_lock, flags); |
| 332 | } |
| 333 | |
Daniel Walker | 2b01370 | 2006-12-10 02:21:30 -0800 | [diff] [blame] | 334 | #ifdef CONFIG_SYSFS |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 335 | /** |
| 336 | * sysfs_show_current_clocksources - sysfs interface for current clocksource |
| 337 | * @dev: unused |
| 338 | * @buf: char buffer to be filled with clocksource list |
| 339 | * |
| 340 | * Provides sysfs interface for listing current clocksource. |
| 341 | */ |
| 342 | static ssize_t |
| 343 | sysfs_show_current_clocksources(struct sys_device *dev, char *buf) |
| 344 | { |
| 345 | char *curr = buf; |
| 346 | |
| 347 | spin_lock_irq(&clocksource_lock); |
| 348 | curr += sprintf(curr, "%s ", curr_clocksource->name); |
| 349 | spin_unlock_irq(&clocksource_lock); |
| 350 | |
| 351 | curr += sprintf(curr, "\n"); |
| 352 | |
| 353 | return curr - buf; |
| 354 | } |
| 355 | |
| 356 | /** |
| 357 | * sysfs_override_clocksource - interface for manually overriding clocksource |
| 358 | * @dev: unused |
| 359 | * @buf: name of override clocksource |
| 360 | * @count: length of buffer |
| 361 | * |
| 362 | * Takes input from sysfs interface for manually overriding the default |
| 363 | * clocksource selction. |
| 364 | */ |
| 365 | static ssize_t sysfs_override_clocksource(struct sys_device *dev, |
| 366 | const char *buf, size_t count) |
| 367 | { |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 368 | struct clocksource *ovr = NULL; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 369 | size_t ret = count; |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 370 | int len; |
| 371 | |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 372 | /* strings from sysfs write are not 0 terminated! */ |
| 373 | if (count >= sizeof(override_name)) |
| 374 | return -EINVAL; |
| 375 | |
| 376 | /* strip of \n: */ |
| 377 | if (buf[count-1] == '\n') |
| 378 | count--; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 379 | |
| 380 | spin_lock_irq(&clocksource_lock); |
| 381 | |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 382 | if (count > 0) |
| 383 | memcpy(override_name, buf, count); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 384 | override_name[count] = 0; |
| 385 | |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 386 | len = strlen(override_name); |
| 387 | if (len) { |
Matthias Kaehlcke | 2e19758 | 2007-10-18 23:39:58 -0700 | [diff] [blame^] | 388 | struct clocksource *cs; |
| 389 | |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 390 | ovr = clocksource_override; |
| 391 | /* try to select it: */ |
Matthias Kaehlcke | 2e19758 | 2007-10-18 23:39:58 -0700 | [diff] [blame^] | 392 | list_for_each_entry(cs, &clocksource_list, list) { |
Thomas Gleixner | 92c7e00 | 2007-02-16 01:27:33 -0800 | [diff] [blame] | 393 | if (strlen(cs->name) == len && |
| 394 | !strcmp(cs->name, override_name)) |
| 395 | ovr = cs; |
| 396 | } |
| 397 | } |
| 398 | |
| 399 | /* Reselect, when the override name has changed */ |
| 400 | if (ovr != clocksource_override) { |
| 401 | clocksource_override = ovr; |
| 402 | next_clocksource = select_clocksource(); |
| 403 | } |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 404 | |
| 405 | spin_unlock_irq(&clocksource_lock); |
| 406 | |
| 407 | return ret; |
| 408 | } |
| 409 | |
| 410 | /** |
| 411 | * sysfs_show_available_clocksources - sysfs interface for listing clocksource |
| 412 | * @dev: unused |
| 413 | * @buf: char buffer to be filled with clocksource list |
| 414 | * |
| 415 | * Provides sysfs interface for listing registered clocksources |
| 416 | */ |
| 417 | static ssize_t |
| 418 | sysfs_show_available_clocksources(struct sys_device *dev, char *buf) |
| 419 | { |
Matthias Kaehlcke | 2e19758 | 2007-10-18 23:39:58 -0700 | [diff] [blame^] | 420 | struct clocksource *src; |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 421 | char *curr = buf; |
| 422 | |
| 423 | spin_lock_irq(&clocksource_lock); |
Matthias Kaehlcke | 2e19758 | 2007-10-18 23:39:58 -0700 | [diff] [blame^] | 424 | list_for_each_entry(src, &clocksource_list, list) { |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 425 | curr += sprintf(curr, "%s ", src->name); |
| 426 | } |
| 427 | spin_unlock_irq(&clocksource_lock); |
| 428 | |
| 429 | curr += sprintf(curr, "\n"); |
| 430 | |
| 431 | return curr - buf; |
| 432 | } |
| 433 | |
| 434 | /* |
| 435 | * Sysfs setup bits: |
| 436 | */ |
| 437 | static SYSDEV_ATTR(current_clocksource, 0600, sysfs_show_current_clocksources, |
Daniel Walker | f5f1a24 | 2006-12-10 02:21:33 -0800 | [diff] [blame] | 438 | sysfs_override_clocksource); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 439 | |
| 440 | static SYSDEV_ATTR(available_clocksource, 0600, |
Daniel Walker | f5f1a24 | 2006-12-10 02:21:33 -0800 | [diff] [blame] | 441 | sysfs_show_available_clocksources, NULL); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 442 | |
| 443 | static struct sysdev_class clocksource_sysclass = { |
| 444 | set_kset_name("clocksource"), |
| 445 | }; |
| 446 | |
| 447 | static struct sys_device device_clocksource = { |
| 448 | .id = 0, |
| 449 | .cls = &clocksource_sysclass, |
| 450 | }; |
| 451 | |
john stultz | ad59617 | 2006-06-26 00:25:06 -0700 | [diff] [blame] | 452 | static int __init init_clocksource_sysfs(void) |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 453 | { |
| 454 | int error = sysdev_class_register(&clocksource_sysclass); |
| 455 | |
| 456 | if (!error) |
| 457 | error = sysdev_register(&device_clocksource); |
| 458 | if (!error) |
| 459 | error = sysdev_create_file( |
| 460 | &device_clocksource, |
| 461 | &attr_current_clocksource); |
| 462 | if (!error) |
| 463 | error = sysdev_create_file( |
| 464 | &device_clocksource, |
| 465 | &attr_available_clocksource); |
| 466 | return error; |
| 467 | } |
| 468 | |
| 469 | device_initcall(init_clocksource_sysfs); |
Daniel Walker | 2b01370 | 2006-12-10 02:21:30 -0800 | [diff] [blame] | 470 | #endif /* CONFIG_SYSFS */ |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 471 | |
| 472 | /** |
| 473 | * boot_override_clocksource - boot clock override |
| 474 | * @str: override name |
| 475 | * |
| 476 | * Takes a clocksource= boot argument and uses it |
| 477 | * as the clocksource override name. |
| 478 | */ |
| 479 | static int __init boot_override_clocksource(char* str) |
| 480 | { |
| 481 | unsigned long flags; |
| 482 | spin_lock_irqsave(&clocksource_lock, flags); |
| 483 | if (str) |
| 484 | strlcpy(override_name, str, sizeof(override_name)); |
| 485 | spin_unlock_irqrestore(&clocksource_lock, flags); |
| 486 | return 1; |
| 487 | } |
| 488 | |
| 489 | __setup("clocksource=", boot_override_clocksource); |
| 490 | |
| 491 | /** |
| 492 | * boot_override_clock - Compatibility layer for deprecated boot option |
| 493 | * @str: override name |
| 494 | * |
| 495 | * DEPRECATED! Takes a clock= boot argument and uses it |
| 496 | * as the clocksource override name |
| 497 | */ |
| 498 | static int __init boot_override_clock(char* str) |
| 499 | { |
john stultz | 5d0cf41 | 2006-06-26 00:25:12 -0700 | [diff] [blame] | 500 | if (!strcmp(str, "pmtmr")) { |
| 501 | printk("Warning: clock=pmtmr is deprecated. " |
| 502 | "Use clocksource=acpi_pm.\n"); |
| 503 | return boot_override_clocksource("acpi_pm"); |
| 504 | } |
| 505 | printk("Warning! clock= boot option is deprecated. " |
| 506 | "Use clocksource=xyz\n"); |
john stultz | 734efb4 | 2006-06-26 00:25:05 -0700 | [diff] [blame] | 507 | return boot_override_clocksource(str); |
| 508 | } |
| 509 | |
| 510 | __setup("clock=", boot_override_clock); |