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> |
4f86d3a8 | 14 | #include <linux/cpuidle.h> |
a06df062 | 15 | #include <linux/cpumask.h> |
ee7a1438 | 16 | #include <linux/tick.h> |
4f86d3a8 LB |
17 | |
18 | #include "cpuidle.h" | |
19 | ||
4f86d3a8 LB |
20 | DEFINE_SPINLOCK(cpuidle_driver_lock); |
21 | ||
82467a5a | 22 | #ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS |
bf4d1b5d | 23 | |
82467a5a DL |
24 | static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers); |
25 | ||
6d19cb93 DL |
26 | /** |
27 | * __cpuidle_get_cpu_driver - return the cpuidle driver tied to a CPU. | |
28 | * @cpu: the CPU handled by the driver | |
29 | * | |
30 | * Returns a pointer to struct cpuidle_driver or NULL if no driver has been | |
31 | * registered for @cpu. | |
32 | */ | |
82467a5a | 33 | static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) |
13dd52f1 | 34 | { |
82467a5a | 35 | return per_cpu(cpuidle_drivers, cpu); |
a06df062 DL |
36 | } |
37 | ||
6d19cb93 DL |
38 | /** |
39 | * __cpuidle_unset_driver - unset per CPU driver variables. | |
40 | * @drv: a valid pointer to a struct cpuidle_driver | |
41 | * | |
42 | * For each CPU in the driver's CPU mask, unset the registered driver per CPU | |
43 | * variable. If @drv is different from the registered driver, the corresponding | |
44 | * variable is not cleared. | |
45 | */ | |
82467a5a | 46 | static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) |
a06df062 | 47 | { |
82467a5a | 48 | int cpu; |
a06df062 | 49 | |
82467a5a | 50 | for_each_cpu(cpu, drv->cpumask) { |
a06df062 | 51 | |
82467a5a | 52 | if (drv != __cpuidle_get_cpu_driver(cpu)) |
a06df062 DL |
53 | continue; |
54 | ||
82467a5a | 55 | per_cpu(cpuidle_drivers, cpu) = NULL; |
a06df062 | 56 | } |
13dd52f1 DL |
57 | } |
58 | ||
6d19cb93 | 59 | /** |
caf4a36e | 60 | * __cpuidle_set_driver - set per CPU driver variables for the given driver. |
6d19cb93 DL |
61 | * @drv: a valid pointer to a struct cpuidle_driver |
62 | * | |
63 | * For each CPU in the driver's cpumask, unset the registered driver per CPU | |
64 | * to @drv. | |
65 | * | |
66 | * Returns 0 on success, -EBUSY if the CPUs have driver(s) already. | |
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) { |
ed953472 | 73 | |
82467a5a DL |
74 | if (__cpuidle_get_cpu_driver(cpu)) { |
75 | __cpuidle_unset_driver(drv); | |
76 | return -EBUSY; | |
77 | } | |
ed953472 | 78 | |
82467a5a DL |
79 | per_cpu(cpuidle_drivers, cpu) = drv; |
80 | } | |
42f67f2a | 81 | |
13dd52f1 DL |
82 | return 0; |
83 | } | |
84 | ||
82467a5a | 85 | #else |
13dd52f1 | 86 | |
82467a5a | 87 | static struct cpuidle_driver *cpuidle_curr_driver; |
a06df062 | 88 | |
6d19cb93 DL |
89 | /** |
90 | * __cpuidle_get_cpu_driver - return the global cpuidle driver pointer. | |
91 | * @cpu: ignored without the multiple driver support | |
92 | * | |
93 | * Return a pointer to a struct cpuidle_driver object or NULL if no driver was | |
94 | * previously registered. | |
95 | */ | |
82467a5a DL |
96 | static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu) |
97 | { | |
98 | return cpuidle_curr_driver; | |
bf4d1b5d DL |
99 | } |
100 | ||
6d19cb93 DL |
101 | /** |
102 | * __cpuidle_set_driver - assign the global cpuidle driver variable. | |
103 | * @drv: pointer to a struct cpuidle_driver object | |
104 | * | |
105 | * Returns 0 on success, -EBUSY if the driver is already registered. | |
106 | */ | |
82467a5a DL |
107 | static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) |
108 | { | |
109 | if (cpuidle_curr_driver) | |
110 | return -EBUSY; | |
bf4d1b5d | 111 | |
82467a5a | 112 | cpuidle_curr_driver = drv; |
bf4d1b5d | 113 | |
82467a5a | 114 | return 0; |
bf4d1b5d DL |
115 | } |
116 | ||
6d19cb93 DL |
117 | /** |
118 | * __cpuidle_unset_driver - unset the global cpuidle driver variable. | |
119 | * @drv: a pointer to a struct cpuidle_driver | |
120 | * | |
121 | * Reset the global cpuidle variable to NULL. If @drv does not match the | |
122 | * registered driver, do nothing. | |
123 | */ | |
82467a5a | 124 | static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv) |
bf4d1b5d | 125 | { |
82467a5a DL |
126 | if (drv == cpuidle_curr_driver) |
127 | cpuidle_curr_driver = NULL; | |
bf4d1b5d DL |
128 | } |
129 | ||
82467a5a DL |
130 | #endif |
131 | ||
6d19cb93 | 132 | /** |
ee7a1438 | 133 | * cpuidle_setup_broadcast_timer - enable/disable the broadcast timer on a cpu |
6d19cb93 DL |
134 | * @arg: a void pointer used to match the SMP cross call API |
135 | * | |
ee7a1438 | 136 | * If @arg is NULL broadcast is disabled otherwise enabled |
6d19cb93 | 137 | * |
ee7a1438 TG |
138 | * This function is executed per CPU by an SMP cross call. It's not |
139 | * supposed to be called directly. | |
6d19cb93 | 140 | */ |
82467a5a | 141 | static void cpuidle_setup_broadcast_timer(void *arg) |
bf4d1b5d | 142 | { |
ee7a1438 TG |
143 | if (arg) |
144 | tick_broadcast_enable(); | |
145 | else | |
146 | tick_broadcast_disable(); | |
bf4d1b5d DL |
147 | } |
148 | ||
6d19cb93 DL |
149 | /** |
150 | * __cpuidle_driver_init - initialize the driver's internal data | |
151 | * @drv: a valid pointer to a struct cpuidle_driver | |
6d19cb93 | 152 | */ |
e437f3e3 | 153 | static void __cpuidle_driver_init(struct cpuidle_driver *drv) |
bf4d1b5d | 154 | { |
82467a5a | 155 | int i; |
bf4d1b5d | 156 | |
82467a5a | 157 | drv->refcnt = 0; |
bf4d1b5d | 158 | |
6d19cb93 DL |
159 | /* |
160 | * Use all possible CPUs as the default, because if the kernel boots | |
161 | * with some CPUs offline and then we online one of them, the CPU | |
162 | * notifier has to know which driver to assign. | |
163 | */ | |
82467a5a DL |
164 | if (!drv->cpumask) |
165 | drv->cpumask = (struct cpumask *)cpu_possible_mask; | |
bf4d1b5d | 166 | |
6d19cb93 DL |
167 | /* |
168 | * Look for the timer stop flag in the different states, so that we know | |
169 | * if the broadcast timer has to be set up. The loop is in the reverse | |
caf4a36e | 170 | * order, because usually one of the deeper states have this flag set. |
6d19cb93 | 171 | */ |
82467a5a | 172 | for (i = drv->state_count - 1; i >= 0 ; i--) { |
b171a856 VK |
173 | if (drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP) { |
174 | drv->bctimer = 1; | |
175 | break; | |
176 | } | |
82467a5a | 177 | } |
bf4d1b5d DL |
178 | } |
179 | ||
d7c7f103 VK |
180 | #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
181 | static int poll_idle(struct cpuidle_device *dev, | |
182 | struct cpuidle_driver *drv, int index) | |
183 | { | |
d7c7f103 | 184 | local_irq_enable(); |
84c40708 AL |
185 | if (!current_set_polling_and_test()) { |
186 | while (!need_resched()) | |
187 | cpu_relax(); | |
188 | } | |
189 | current_clr_polling(); | |
d7c7f103 | 190 | |
d7c7f103 VK |
191 | return index; |
192 | } | |
193 | ||
194 | static void poll_idle_init(struct cpuidle_driver *drv) | |
195 | { | |
196 | struct cpuidle_state *state = &drv->states[0]; | |
197 | ||
198 | snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); | |
199 | snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); | |
200 | state->exit_latency = 0; | |
201 | state->target_residency = 0; | |
202 | state->power_usage = -1; | |
d7c7f103 VK |
203 | state->enter = poll_idle; |
204 | state->disabled = false; | |
205 | } | |
206 | #else | |
207 | static void poll_idle_init(struct cpuidle_driver *drv) {} | |
208 | #endif /* !CONFIG_ARCH_HAS_CPU_RELAX */ | |
209 | ||
6d19cb93 DL |
210 | /** |
211 | * __cpuidle_register_driver: register the driver | |
212 | * @drv: a valid pointer to a struct cpuidle_driver | |
213 | * | |
214 | * Do some sanity checks, initialize the driver, assign the driver to the | |
215 | * global cpuidle driver variable(s) and set up the broadcast timer if the | |
216 | * cpuidle driver has some states that shut down the local timer. | |
217 | * | |
218 | * Returns 0 on success, a negative error code otherwise: | |
219 | * * -EINVAL if the driver pointer is NULL or no idle states are available | |
220 | * * -ENODEV if the cpuidle framework is disabled | |
221 | * * -EBUSY if the driver is already assigned to the global variable(s) | |
222 | */ | |
82467a5a | 223 | static int __cpuidle_register_driver(struct cpuidle_driver *drv) |
bf4d1b5d DL |
224 | { |
225 | int ret; | |
226 | ||
82467a5a DL |
227 | if (!drv || !drv->state_count) |
228 | return -EINVAL; | |
bf4d1b5d | 229 | |
abceaa9c XP |
230 | ret = cpuidle_coupled_state_verify(drv); |
231 | if (ret) | |
232 | return ret; | |
233 | ||
82467a5a DL |
234 | if (cpuidle_disabled()) |
235 | return -ENODEV; | |
bf4d1b5d | 236 | |
e437f3e3 | 237 | __cpuidle_driver_init(drv); |
ed953472 | 238 | |
82467a5a DL |
239 | ret = __cpuidle_set_driver(drv); |
240 | if (ret) | |
241 | return ret; | |
13dd52f1 | 242 | |
82467a5a DL |
243 | if (drv->bctimer) |
244 | on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer, | |
ee7a1438 | 245 | (void *)1, 1); |
4f86d3a8 | 246 | |
d7c7f103 VK |
247 | poll_idle_init(drv); |
248 | ||
82467a5a | 249 | return 0; |
4f86d3a8 | 250 | } |
4f86d3a8 | 251 | |
752138df | 252 | /** |
6d19cb93 DL |
253 | * __cpuidle_unregister_driver - unregister the driver |
254 | * @drv: a valid pointer to a struct cpuidle_driver | |
255 | * | |
256 | * Check if the driver is no longer in use, reset the global cpuidle driver | |
257 | * variable(s) and disable the timer broadcast notification mechanism if it was | |
258 | * in use. | |
259 | * | |
752138df | 260 | */ |
82467a5a | 261 | static void __cpuidle_unregister_driver(struct cpuidle_driver *drv) |
bf4d1b5d | 262 | { |
82467a5a DL |
263 | if (WARN_ON(drv->refcnt > 0)) |
264 | return; | |
bf4d1b5d | 265 | |
82467a5a DL |
266 | if (drv->bctimer) { |
267 | drv->bctimer = 0; | |
268 | on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer, | |
ee7a1438 | 269 | NULL, 1); |
82467a5a | 270 | } |
bf4d1b5d | 271 | |
82467a5a | 272 | __cpuidle_unset_driver(drv); |
752138df | 273 | } |
bf4d1b5d DL |
274 | |
275 | /** | |
276 | * cpuidle_register_driver - registers a driver | |
6d19cb93 DL |
277 | * @drv: a pointer to a valid struct cpuidle_driver |
278 | * | |
279 | * Register the driver under a lock to prevent concurrent attempts to | |
280 | * [un]register the driver from occuring at the same time. | |
281 | * | |
282 | * Returns 0 on success, a negative error code (returned by | |
283 | * __cpuidle_register_driver()) otherwise. | |
bf4d1b5d DL |
284 | */ |
285 | int cpuidle_register_driver(struct cpuidle_driver *drv) | |
286 | { | |
82467a5a | 287 | int ret; |
bf4d1b5d | 288 | |
bf4d1b5d | 289 | spin_lock(&cpuidle_driver_lock); |
82467a5a | 290 | ret = __cpuidle_register_driver(drv); |
bf4d1b5d | 291 | spin_unlock(&cpuidle_driver_lock); |
bf4d1b5d DL |
292 | |
293 | return ret; | |
294 | } | |
295 | EXPORT_SYMBOL_GPL(cpuidle_register_driver); | |
752138df | 296 | |
4f86d3a8 LB |
297 | /** |
298 | * cpuidle_unregister_driver - unregisters a driver | |
6d19cb93 DL |
299 | * @drv: a pointer to a valid struct cpuidle_driver |
300 | * | |
301 | * Unregisters the cpuidle driver under a lock to prevent concurrent attempts | |
302 | * to [un]register the driver from occuring at the same time. @drv has to | |
303 | * match the currently registered driver. | |
4f86d3a8 LB |
304 | */ |
305 | void cpuidle_unregister_driver(struct cpuidle_driver *drv) | |
306 | { | |
4f86d3a8 | 307 | spin_lock(&cpuidle_driver_lock); |
82467a5a | 308 | __cpuidle_unregister_driver(drv); |
4f86d3a8 LB |
309 | spin_unlock(&cpuidle_driver_lock); |
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 | |
6d19cb93 DL |
347 | /** |
348 | * cpuidle_driver_ref - get a reference to the driver. | |
349 | * | |
350 | * Increment the reference counter of the cpuidle driver associated with | |
351 | * the current CPU. | |
352 | * | |
353 | * Returns a pointer to the driver, or NULL if the current CPU has no driver. | |
354 | */ | |
6e797a07 RW |
355 | struct cpuidle_driver *cpuidle_driver_ref(void) |
356 | { | |
357 | struct cpuidle_driver *drv; | |
358 | ||
359 | spin_lock(&cpuidle_driver_lock); | |
360 | ||
13dd52f1 | 361 | drv = cpuidle_get_driver(); |
3b9c10e9 DF |
362 | if (drv) |
363 | drv->refcnt++; | |
6e797a07 RW |
364 | |
365 | spin_unlock(&cpuidle_driver_lock); | |
366 | return drv; | |
367 | } | |
368 | ||
6d19cb93 DL |
369 | /** |
370 | * cpuidle_driver_unref - puts down the refcount for the driver | |
371 | * | |
372 | * Decrement the reference counter of the cpuidle driver associated with | |
373 | * the current CPU. | |
374 | */ | |
6e797a07 RW |
375 | void cpuidle_driver_unref(void) |
376 | { | |
0d09d312 | 377 | struct cpuidle_driver *drv; |
42f67f2a | 378 | |
6e797a07 RW |
379 | spin_lock(&cpuidle_driver_lock); |
380 | ||
0d09d312 | 381 | drv = cpuidle_get_driver(); |
42f67f2a DL |
382 | if (drv && !WARN_ON(drv->refcnt <= 0)) |
383 | drv->refcnt--; | |
6e797a07 RW |
384 | |
385 | spin_unlock(&cpuidle_driver_lock); | |
386 | } |