Commit | Line | Data |
---|---|---|
4f86d3a8 LB |
1 | /* |
2 | * driver.c - driver support | |
3 | * | |
4 | * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> | |
5 | * Shaohua Li <shaohua.li@intel.com> | |
6 | * Adam Belay <abelay@novell.com> | |
7 | * | |
8 | * This code is licenced under the GPL. | |
9 | */ | |
10 | ||
11 | #include <linux/mutex.h> | |
12 | #include <linux/module.h> | |
d7c7f103 | 13 | #include <linux/sched.h> |
4c822698 | 14 | #include <linux/sched/idle.h> |
4f86d3a8 | 15 | #include <linux/cpuidle.h> |
a06df062 | 16 | #include <linux/cpumask.h> |
ee7a1438 | 17 | #include <linux/tick.h> |
6727ad9e | 18 | #include <linux/cpu.h> |
4f86d3a8 LB |
19 | |
20 | #include "cpuidle.h" | |
21 | ||
4f86d3a8 LB |
22 | DEFINE_SPINLOCK(cpuidle_driver_lock); |
23 | ||
82467a5a | 24 | #ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS |
bf4d1b5d | 25 | |
82467a5a DL |
26 | static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers); |
27 | ||
6d19cb93 DL |
28 | /** |
29 | * __cpuidle_get_cpu_driver - return the cpuidle driver tied to a CPU. | |
30 | * @cpu: the CPU handled by the driver | |
31 | * | |
32 | * Returns a pointer to struct cpuidle_driver or NULL if no driver has been | |
33 | * registered for @cpu. | |
34 | */ | |
82467a5a | 35 | static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) |
13dd52f1 | 36 | { |
82467a5a | 37 | return per_cpu(cpuidle_drivers, cpu); |
a06df062 DL |
38 | } |
39 | ||
6d19cb93 DL |
40 | /** |
41 | * __cpuidle_unset_driver - unset per CPU driver variables. | |
42 | * @drv: a valid pointer to a struct cpuidle_driver | |
43 | * | |
44 | * For each CPU in the driver's CPU mask, unset the registered driver per CPU | |
45 | * variable. If @drv is different from the registered driver, the corresponding | |
46 | * variable is not cleared. | |
47 | */ | |
82467a5a | 48 | static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) |
a06df062 | 49 | { |
82467a5a | 50 | int cpu; |
a06df062 | 51 | |
82467a5a | 52 | for_each_cpu(cpu, drv->cpumask) { |
a06df062 | 53 | |
82467a5a | 54 | if (drv != __cpuidle_get_cpu_driver(cpu)) |
a06df062 DL |
55 | continue; |
56 | ||
82467a5a | 57 | per_cpu(cpuidle_drivers, cpu) = NULL; |
a06df062 | 58 | } |
13dd52f1 DL |
59 | } |
60 | ||
6d19cb93 | 61 | /** |
caf4a36e | 62 | * __cpuidle_set_driver - set per CPU driver variables for the given driver. |
6d19cb93 DL |
63 | * @drv: a valid pointer to a struct cpuidle_driver |
64 | * | |
918c1fe9 ZD |
65 | * Returns 0 on success, -EBUSY if any CPU in the cpumask have a driver |
66 | * different from drv already. | |
6d19cb93 | 67 | */ |
82467a5a | 68 | static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) |
4f86d3a8 | 69 | { |
82467a5a | 70 | int cpu; |
62027aea | 71 | |
82467a5a | 72 | for_each_cpu(cpu, drv->cpumask) { |
918c1fe9 | 73 | struct cpuidle_driver *old_drv; |
ed953472 | 74 | |
918c1fe9 ZD |
75 | old_drv = __cpuidle_get_cpu_driver(cpu); |
76 | if (old_drv && old_drv != drv) | |
82467a5a | 77 | return -EBUSY; |
918c1fe9 | 78 | } |
ed953472 | 79 | |
918c1fe9 | 80 | for_each_cpu(cpu, drv->cpumask) |
82467a5a | 81 | per_cpu(cpuidle_drivers, cpu) = drv; |
42f67f2a | 82 | |
13dd52f1 DL |
83 | return 0; |
84 | } | |
85 | ||
82467a5a | 86 | #else |
13dd52f1 | 87 | |
82467a5a | 88 | static struct cpuidle_driver *cpuidle_curr_driver; |
a06df062 | 89 | |
6d19cb93 DL |
90 | /** |
91 | * __cpuidle_get_cpu_driver - return the global cpuidle driver pointer. | |
92 | * @cpu: ignored without the multiple driver support | |
93 | * | |
94 | * Return a pointer to a struct cpuidle_driver object or NULL if no driver was | |
95 | * previously registered. | |
96 | */ | |
82467a5a DL |
97 | static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) |
98 | { | |
99 | return cpuidle_curr_driver; | |
bf4d1b5d DL |
100 | } |
101 | ||
6d19cb93 DL |
102 | /** |
103 | * __cpuidle_set_driver - assign the global cpuidle driver variable. | |
104 | * @drv: pointer to a struct cpuidle_driver object | |
105 | * | |
106 | * Returns 0 on success, -EBUSY if the driver is already registered. | |
107 | */ | |
82467a5a DL |
108 | static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) |
109 | { | |
110 | if (cpuidle_curr_driver) | |
111 | return -EBUSY; | |
bf4d1b5d | 112 | |
82467a5a | 113 | cpuidle_curr_driver = drv; |
bf4d1b5d | 114 | |
82467a5a | 115 | return 0; |
bf4d1b5d DL |
116 | } |
117 | ||
6d19cb93 DL |
118 | /** |
119 | * __cpuidle_unset_driver - unset the global cpuidle driver variable. | |
120 | * @drv: a pointer to a struct cpuidle_driver | |
121 | * | |
122 | * Reset the global cpuidle variable to NULL. If @drv does not match the | |
123 | * registered driver, do nothing. | |
124 | */ | |
82467a5a | 125 | static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) |
bf4d1b5d | 126 | { |
82467a5a DL |
127 | if (drv == cpuidle_curr_driver) |
128 | cpuidle_curr_driver = NULL; | |
bf4d1b5d DL |
129 | } |
130 | ||
82467a5a DL |
131 | #endif |
132 | ||
6d19cb93 | 133 | /** |
ee7a1438 | 134 | * cpuidle_setup_broadcast_timer - enable/disable the broadcast timer on a cpu |
6d19cb93 DL |
135 | * @arg: a void pointer used to match the SMP cross call API |
136 | * | |
ee7a1438 | 137 | * If @arg is NULL broadcast is disabled otherwise enabled |
6d19cb93 | 138 | * |
ee7a1438 TG |
139 | * This function is executed per CPU by an SMP cross call. It's not |
140 | * supposed to be called directly. | |
6d19cb93 | 141 | */ |
82467a5a | 142 | static void cpuidle_setup_broadcast_timer(void *arg) |
bf4d1b5d | 143 | { |
ee7a1438 TG |
144 | if (arg) |
145 | tick_broadcast_enable(); | |
146 | else | |
147 | tick_broadcast_disable(); | |
bf4d1b5d DL |
148 | } |
149 | ||
6d19cb93 DL |
150 | /** |
151 | * __cpuidle_driver_init - initialize the driver's internal data | |
152 | * @drv: a valid pointer to a struct cpuidle_driver | |
6d19cb93 | 153 | */ |
e437f3e3 | 154 | static void __cpuidle_driver_init(struct cpuidle_driver *drv) |
bf4d1b5d | 155 | { |
82467a5a | 156 | int i; |
bf4d1b5d | 157 | |
6d19cb93 DL |
158 | /* |
159 | * Use all possible CPUs as the default, because if the kernel boots | |
160 | * with some CPUs offline and then we online one of them, the CPU | |
161 | * notifier has to know which driver to assign. | |
162 | */ | |
82467a5a DL |
163 | if (!drv->cpumask) |
164 | drv->cpumask = (struct cpumask *)cpu_possible_mask; | |
bf4d1b5d | 165 | |
c1d51f68 RW |
166 | for (i = 0; i < drv->state_count; i++) { |
167 | struct cpuidle_state *s = &drv->states[i]; | |
168 | ||
169 | /* | |
170 | * Look for the timer stop flag in the different states and if | |
171 | * it is found, indicate that the broadcast timer has to be set | |
172 | * up. | |
173 | */ | |
174 | if (s->flags & CPUIDLE_FLAG_TIMER_STOP) | |
b171a856 | 175 | drv->bctimer = 1; |
c1d51f68 RW |
176 | |
177 | /* | |
178 | * The core will use the target residency and exit latency | |
179 | * values in nanoseconds, but allow drivers to provide them in | |
180 | * microseconds too. | |
181 | */ | |
182 | if (s->target_residency > 0) | |
183 | s->target_residency_ns = s->target_residency * NSEC_PER_USEC; | |
184 | ||
185 | if (s->exit_latency > 0) | |
186 | s->exit_latency_ns = s->exit_latency * NSEC_PER_USEC; | |
82467a5a | 187 | } |
bf4d1b5d DL |
188 | } |
189 | ||
6d19cb93 DL |
190 | /** |
191 | * __cpuidle_register_driver: register the driver | |
192 | * @drv: a valid pointer to a struct cpuidle_driver | |
193 | * | |
194 | * Do some sanity checks, initialize the driver, assign the driver to the | |
195 | * global cpuidle driver variable(s) and set up the broadcast timer if the | |
196 | * cpuidle driver has some states that shut down the local timer. | |
197 | * | |
198 | * Returns 0 on success, a negative error code otherwise: | |
199 | * * -EINVAL if the driver pointer is NULL or no idle states are available | |
200 | * * -ENODEV if the cpuidle framework is disabled | |
201 | * * -EBUSY if the driver is already assigned to the global variable(s) | |
202 | */ | |
82467a5a | 203 | static int __cpuidle_register_driver(struct cpuidle_driver *drv) |
bf4d1b5d DL |
204 | { |
205 | int ret; | |
206 | ||
82467a5a DL |
207 | if (!drv || !drv->state_count) |
208 | return -EINVAL; | |
bf4d1b5d | 209 | |
abceaa9c XP |
210 | ret = cpuidle_coupled_state_verify(drv); |
211 | if (ret) | |
212 | return ret; | |
213 | ||
82467a5a DL |
214 | if (cpuidle_disabled()) |
215 | return -ENODEV; | |
bf4d1b5d | 216 | |
e437f3e3 | 217 | __cpuidle_driver_init(drv); |
ed953472 | 218 | |
82467a5a DL |
219 | ret = __cpuidle_set_driver(drv); |
220 | if (ret) | |
221 | return ret; | |
13dd52f1 | 222 | |
82467a5a DL |
223 | if (drv->bctimer) |
224 | on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer, | |
ee7a1438 | 225 | (void *)1, 1); |
4f86d3a8 | 226 | |
82467a5a | 227 | return 0; |
4f86d3a8 | 228 | } |
4f86d3a8 | 229 | |
752138df | 230 | /** |
6d19cb93 DL |
231 | * __cpuidle_unregister_driver - unregister the driver |
232 | * @drv: a valid pointer to a struct cpuidle_driver | |
233 | * | |
234 | * Check if the driver is no longer in use, reset the global cpuidle driver | |
235 | * variable(s) and disable the timer broadcast notification mechanism if it was | |
236 | * in use. | |
237 | * | |
752138df | 238 | */ |
82467a5a | 239 | static void __cpuidle_unregister_driver(struct cpuidle_driver *drv) |
bf4d1b5d | 240 | { |
82467a5a DL |
241 | if (drv->bctimer) { |
242 | drv->bctimer = 0; | |
243 | on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer, | |
ee7a1438 | 244 | NULL, 1); |
82467a5a | 245 | } |
bf4d1b5d | 246 | |
82467a5a | 247 | __cpuidle_unset_driver(drv); |
752138df | 248 | } |
bf4d1b5d DL |
249 | |
250 | /** | |
251 | * cpuidle_register_driver - registers a driver | |
6d19cb93 DL |
252 | * @drv: a pointer to a valid struct cpuidle_driver |
253 | * | |
254 | * Register the driver under a lock to prevent concurrent attempts to | |
255 | * [un]register the driver from occuring at the same time. | |
256 | * | |
257 | * Returns 0 on success, a negative error code (returned by | |
258 | * __cpuidle_register_driver()) otherwise. | |
bf4d1b5d DL |
259 | */ |
260 | int cpuidle_register_driver(struct cpuidle_driver *drv) | |
261 | { | |
cb5d8c45 | 262 | struct cpuidle_governor *gov; |
82467a5a | 263 | int ret; |
bf4d1b5d | 264 | |
bf4d1b5d | 265 | spin_lock(&cpuidle_driver_lock); |
82467a5a | 266 | ret = __cpuidle_register_driver(drv); |
bf4d1b5d | 267 | spin_unlock(&cpuidle_driver_lock); |
bf4d1b5d | 268 | |
cb5d8c45 JM |
269 | if (!ret && !strlen(param_governor) && drv->governor && |
270 | (cpuidle_get_driver() == drv)) { | |
271 | mutex_lock(&cpuidle_lock); | |
272 | gov = cpuidle_find_governor(drv->governor); | |
273 | if (gov) { | |
274 | cpuidle_prev_governor = cpuidle_curr_governor; | |
275 | if (cpuidle_switch_governor(gov) < 0) | |
276 | cpuidle_prev_governor = NULL; | |
277 | } | |
278 | mutex_unlock(&cpuidle_lock); | |
279 | } | |
280 | ||
bf4d1b5d DL |
281 | return ret; |
282 | } | |
283 | EXPORT_SYMBOL_GPL(cpuidle_register_driver); | |
752138df | 284 | |
4f86d3a8 LB |
285 | /** |
286 | * cpuidle_unregister_driver - unregisters a driver | |
6d19cb93 DL |
287 | * @drv: a pointer to a valid struct cpuidle_driver |
288 | * | |
289 | * Unregisters the cpuidle driver under a lock to prevent concurrent attempts | |
290 | * to [un]register the driver from occuring at the same time. @drv has to | |
291 | * match the currently registered driver. | |
4f86d3a8 LB |
292 | */ |
293 | void cpuidle_unregister_driver(struct cpuidle_driver *drv) | |
294 | { | |
cb5d8c45 JM |
295 | bool enabled = (cpuidle_get_driver() == drv); |
296 | ||
4f86d3a8 | 297 | spin_lock(&cpuidle_driver_lock); |
82467a5a | 298 | __cpuidle_unregister_driver(drv); |
4f86d3a8 | 299 | spin_unlock(&cpuidle_driver_lock); |
cb5d8c45 JM |
300 | |
301 | if (!enabled) | |
302 | return; | |
303 | ||
304 | mutex_lock(&cpuidle_lock); | |
305 | if (cpuidle_prev_governor) { | |
306 | if (!cpuidle_switch_governor(cpuidle_prev_governor)) | |
307 | cpuidle_prev_governor = NULL; | |
308 | } | |
309 | mutex_unlock(&cpuidle_lock); | |
4f86d3a8 | 310 | } |
4f86d3a8 | 311 | EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); |
bf4d1b5d DL |
312 | |
313 | /** | |
6d19cb93 DL |
314 | * cpuidle_get_driver - return the driver tied to the current CPU. |
315 | * | |
316 | * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered. | |
bf4d1b5d DL |
317 | */ |
318 | struct cpuidle_driver *cpuidle_get_driver(void) | |
319 | { | |
320 | struct cpuidle_driver *drv; | |
321 | int cpu; | |
322 | ||
323 | cpu = get_cpu(); | |
324 | drv = __cpuidle_get_cpu_driver(cpu); | |
325 | put_cpu(); | |
326 | ||
327 | return drv; | |
328 | } | |
329 | EXPORT_SYMBOL_GPL(cpuidle_get_driver); | |
330 | ||
331 | /** | |
6d19cb93 DL |
332 | * cpuidle_get_cpu_driver - return the driver registered for a CPU. |
333 | * @dev: a valid pointer to a struct cpuidle_device | |
334 | * | |
335 | * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered | |
336 | * for the CPU associated with @dev. | |
bf4d1b5d DL |
337 | */ |
338 | struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev) | |
339 | { | |
bf4d1b5d DL |
340 | if (!dev) |
341 | return NULL; | |
342 | ||
ac34d7c8 | 343 | return __cpuidle_get_cpu_driver(dev->cpu); |
bf4d1b5d DL |
344 | } |
345 | EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver); | |
6e797a07 | 346 | |
cbda56d5 RW |
347 | /** |
348 | * cpuidle_driver_state_disabled - Disable or enable an idle state | |
349 | * @drv: cpuidle driver owning the state | |
350 | * @idx: State index | |
351 | * @disable: Whether or not to disable the state | |
352 | */ | |
353 | void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx, | |
354 | bool disable) | |
355 | { | |
356 | unsigned int cpu; | |
357 | ||
358 | mutex_lock(&cpuidle_lock); | |
359 | ||
b0142d66 RW |
360 | spin_lock(&cpuidle_driver_lock); |
361 | ||
362 | if (!drv->cpumask) { | |
363 | drv->states[idx].flags |= CPUIDLE_FLAG_UNUSABLE; | |
364 | goto unlock; | |
365 | } | |
366 | ||
cbda56d5 RW |
367 | for_each_cpu(cpu, drv->cpumask) { |
368 | struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); | |
369 | ||
370 | if (!dev) | |
371 | continue; | |
372 | ||
373 | if (disable) | |
374 | dev->states_usage[idx].disable |= CPUIDLE_STATE_DISABLED_BY_DRIVER; | |
375 | else | |
376 | dev->states_usage[idx].disable &= ~CPUIDLE_STATE_DISABLED_BY_DRIVER; | |
377 | } | |
378 | ||
b0142d66 RW |
379 | unlock: |
380 | spin_unlock(&cpuidle_driver_lock); | |
381 | ||
cbda56d5 RW |
382 | mutex_unlock(&cpuidle_lock); |
383 | } |