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 DL |
15 | #include <linux/cpumask.h> |
16 | #include <linux/clockchips.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 DL |
132 | /** |
133 | * cpuidle_setup_broadcast_timer - enable/disable the broadcast timer | |
134 | * @arg: a void pointer used to match the SMP cross call API | |
135 | * | |
caf4a36e | 136 | * @arg is used as a value of type 'long' with one of the two values: |
6d19cb93 DL |
137 | * - CLOCK_EVT_NOTIFY_BROADCAST_ON |
138 | * - CLOCK_EVT_NOTIFY_BROADCAST_OFF | |
139 | * | |
140 | * Set the broadcast timer notification for the current CPU. This function | |
141 | * is executed per CPU by an SMP cross call. It not supposed to be called | |
142 | * directly. | |
143 | */ | |
82467a5a | 144 | static void cpuidle_setup_broadcast_timer(void *arg) |
bf4d1b5d | 145 | { |
82467a5a DL |
146 | int cpu = smp_processor_id(); |
147 | clockevents_notify((long)(arg), &cpu); | |
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 | |
82467a5a | 158 | drv->refcnt = 0; |
bf4d1b5d | 159 | |
6d19cb93 DL |
160 | /* |
161 | * Use all possible CPUs as the default, because if the kernel boots | |
162 | * with some CPUs offline and then we online one of them, the CPU | |
163 | * notifier has to know which driver to assign. | |
164 | */ | |
82467a5a DL |
165 | if (!drv->cpumask) |
166 | drv->cpumask = (struct cpumask *)cpu_possible_mask; | |
bf4d1b5d | 167 | |
6d19cb93 DL |
168 | /* |
169 | * Look for the timer stop flag in the different states, so that we know | |
170 | * if the broadcast timer has to be set up. The loop is in the reverse | |
caf4a36e | 171 | * order, because usually one of the deeper states have this flag set. |
6d19cb93 | 172 | */ |
82467a5a | 173 | for (i = drv->state_count - 1; i >= 0 ; i--) { |
b171a856 VK |
174 | if (drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP) { |
175 | drv->bctimer = 1; | |
176 | break; | |
177 | } | |
82467a5a | 178 | } |
bf4d1b5d DL |
179 | } |
180 | ||
d7c7f103 VK |
181 | #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
182 | static int poll_idle(struct cpuidle_device *dev, | |
183 | struct cpuidle_driver *drv, int index) | |
184 | { | |
185 | ktime_t t1, t2; | |
186 | s64 diff; | |
187 | ||
188 | t1 = ktime_get(); | |
189 | local_irq_enable(); | |
190 | while (!need_resched()) | |
191 | cpu_relax(); | |
192 | ||
193 | t2 = ktime_get(); | |
194 | diff = ktime_to_us(ktime_sub(t2, t1)); | |
195 | if (diff > INT_MAX) | |
196 | diff = INT_MAX; | |
197 | ||
198 | dev->last_residency = (int) diff; | |
199 | ||
200 | return index; | |
201 | } | |
202 | ||
203 | static void poll_idle_init(struct cpuidle_driver *drv) | |
204 | { | |
205 | struct cpuidle_state *state = &drv->states[0]; | |
206 | ||
207 | snprintf(state->name, CPUIDLE_NAME_LEN, "POLL"); | |
208 | snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); | |
209 | state->exit_latency = 0; | |
210 | state->target_residency = 0; | |
211 | state->power_usage = -1; | |
4b2f0b03 | 212 | state->flags = CPUIDLE_FLAG_TIME_VALID; |
d7c7f103 VK |
213 | state->enter = poll_idle; |
214 | state->disabled = false; | |
215 | } | |
216 | #else | |
217 | static void poll_idle_init(struct cpuidle_driver *drv) {} | |
218 | #endif /* !CONFIG_ARCH_HAS_CPU_RELAX */ | |
219 | ||
6d19cb93 DL |
220 | /** |
221 | * __cpuidle_register_driver: register the driver | |
222 | * @drv: a valid pointer to a struct cpuidle_driver | |
223 | * | |
224 | * Do some sanity checks, initialize the driver, assign the driver to the | |
225 | * global cpuidle driver variable(s) and set up the broadcast timer if the | |
226 | * cpuidle driver has some states that shut down the local timer. | |
227 | * | |
228 | * Returns 0 on success, a negative error code otherwise: | |
229 | * * -EINVAL if the driver pointer is NULL or no idle states are available | |
230 | * * -ENODEV if the cpuidle framework is disabled | |
231 | * * -EBUSY if the driver is already assigned to the global variable(s) | |
232 | */ | |
82467a5a | 233 | static int __cpuidle_register_driver(struct cpuidle_driver *drv) |
bf4d1b5d DL |
234 | { |
235 | int ret; | |
236 | ||
82467a5a DL |
237 | if (!drv || !drv->state_count) |
238 | return -EINVAL; | |
bf4d1b5d | 239 | |
82467a5a DL |
240 | if (cpuidle_disabled()) |
241 | return -ENODEV; | |
bf4d1b5d | 242 | |
e437f3e3 | 243 | __cpuidle_driver_init(drv); |
ed953472 | 244 | |
82467a5a DL |
245 | ret = __cpuidle_set_driver(drv); |
246 | if (ret) | |
247 | return ret; | |
13dd52f1 | 248 | |
82467a5a DL |
249 | if (drv->bctimer) |
250 | on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer, | |
251 | (void *)CLOCK_EVT_NOTIFY_BROADCAST_ON, 1); | |
4f86d3a8 | 252 | |
d7c7f103 VK |
253 | poll_idle_init(drv); |
254 | ||
82467a5a | 255 | return 0; |
4f86d3a8 | 256 | } |
4f86d3a8 | 257 | |
752138df | 258 | /** |
6d19cb93 DL |
259 | * __cpuidle_unregister_driver - unregister the driver |
260 | * @drv: a valid pointer to a struct cpuidle_driver | |
261 | * | |
262 | * Check if the driver is no longer in use, reset the global cpuidle driver | |
263 | * variable(s) and disable the timer broadcast notification mechanism if it was | |
264 | * in use. | |
265 | * | |
752138df | 266 | */ |
82467a5a | 267 | static void __cpuidle_unregister_driver(struct cpuidle_driver *drv) |
bf4d1b5d | 268 | { |
82467a5a DL |
269 | if (WARN_ON(drv->refcnt > 0)) |
270 | return; | |
bf4d1b5d | 271 | |
82467a5a DL |
272 | if (drv->bctimer) { |
273 | drv->bctimer = 0; | |
274 | on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer, | |
275 | (void *)CLOCK_EVT_NOTIFY_BROADCAST_OFF, 1); | |
276 | } | |
bf4d1b5d | 277 | |
82467a5a | 278 | __cpuidle_unset_driver(drv); |
752138df | 279 | } |
bf4d1b5d DL |
280 | |
281 | /** | |
282 | * cpuidle_register_driver - registers a driver | |
6d19cb93 DL |
283 | * @drv: a pointer to a valid struct cpuidle_driver |
284 | * | |
285 | * Register the driver under a lock to prevent concurrent attempts to | |
286 | * [un]register the driver from occuring at the same time. | |
287 | * | |
288 | * Returns 0 on success, a negative error code (returned by | |
289 | * __cpuidle_register_driver()) otherwise. | |
bf4d1b5d DL |
290 | */ |
291 | int cpuidle_register_driver(struct cpuidle_driver *drv) | |
292 | { | |
82467a5a | 293 | int ret; |
bf4d1b5d | 294 | |
bf4d1b5d | 295 | spin_lock(&cpuidle_driver_lock); |
82467a5a | 296 | ret = __cpuidle_register_driver(drv); |
bf4d1b5d | 297 | spin_unlock(&cpuidle_driver_lock); |
bf4d1b5d DL |
298 | |
299 | return ret; | |
300 | } | |
301 | EXPORT_SYMBOL_GPL(cpuidle_register_driver); | |
752138df | 302 | |
4f86d3a8 LB |
303 | /** |
304 | * cpuidle_unregister_driver - unregisters a driver | |
6d19cb93 DL |
305 | * @drv: a pointer to a valid struct cpuidle_driver |
306 | * | |
307 | * Unregisters the cpuidle driver under a lock to prevent concurrent attempts | |
308 | * to [un]register the driver from occuring at the same time. @drv has to | |
309 | * match the currently registered driver. | |
4f86d3a8 LB |
310 | */ |
311 | void cpuidle_unregister_driver(struct cpuidle_driver *drv) | |
312 | { | |
4f86d3a8 | 313 | spin_lock(&cpuidle_driver_lock); |
82467a5a | 314 | __cpuidle_unregister_driver(drv); |
4f86d3a8 LB |
315 | spin_unlock(&cpuidle_driver_lock); |
316 | } | |
4f86d3a8 | 317 | EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); |
bf4d1b5d DL |
318 | |
319 | /** | |
6d19cb93 DL |
320 | * cpuidle_get_driver - return the driver tied to the current CPU. |
321 | * | |
322 | * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered. | |
bf4d1b5d DL |
323 | */ |
324 | struct cpuidle_driver *cpuidle_get_driver(void) | |
325 | { | |
326 | struct cpuidle_driver *drv; | |
327 | int cpu; | |
328 | ||
329 | cpu = get_cpu(); | |
330 | drv = __cpuidle_get_cpu_driver(cpu); | |
331 | put_cpu(); | |
332 | ||
333 | return drv; | |
334 | } | |
335 | EXPORT_SYMBOL_GPL(cpuidle_get_driver); | |
336 | ||
337 | /** | |
6d19cb93 DL |
338 | * cpuidle_get_cpu_driver - return the driver registered for a CPU. |
339 | * @dev: a valid pointer to a struct cpuidle_device | |
340 | * | |
341 | * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered | |
342 | * for the CPU associated with @dev. | |
bf4d1b5d DL |
343 | */ |
344 | struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev) | |
345 | { | |
bf4d1b5d DL |
346 | if (!dev) |
347 | return NULL; | |
348 | ||
ac34d7c8 | 349 | return __cpuidle_get_cpu_driver(dev->cpu); |
bf4d1b5d DL |
350 | } |
351 | EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver); | |
6e797a07 | 352 | |
6d19cb93 DL |
353 | /** |
354 | * cpuidle_driver_ref - get a reference to the driver. | |
355 | * | |
356 | * Increment the reference counter of the cpuidle driver associated with | |
357 | * the current CPU. | |
358 | * | |
359 | * Returns a pointer to the driver, or NULL if the current CPU has no driver. | |
360 | */ | |
6e797a07 RW |
361 | struct cpuidle_driver *cpuidle_driver_ref(void) |
362 | { | |
363 | struct cpuidle_driver *drv; | |
364 | ||
365 | spin_lock(&cpuidle_driver_lock); | |
366 | ||
13dd52f1 | 367 | drv = cpuidle_get_driver(); |
3b9c10e9 DF |
368 | if (drv) |
369 | drv->refcnt++; | |
6e797a07 RW |
370 | |
371 | spin_unlock(&cpuidle_driver_lock); | |
372 | return drv; | |
373 | } | |
374 | ||
6d19cb93 DL |
375 | /** |
376 | * cpuidle_driver_unref - puts down the refcount for the driver | |
377 | * | |
378 | * Decrement the reference counter of the cpuidle driver associated with | |
379 | * the current CPU. | |
380 | */ | |
6e797a07 RW |
381 | void cpuidle_driver_unref(void) |
382 | { | |
0d09d312 | 383 | struct cpuidle_driver *drv; |
42f67f2a | 384 | |
6e797a07 RW |
385 | spin_lock(&cpuidle_driver_lock); |
386 | ||
0d09d312 | 387 | drv = cpuidle_get_driver(); |
42f67f2a DL |
388 | if (drv && !WARN_ON(drv->refcnt <= 0)) |
389 | drv->refcnt--; | |
6e797a07 RW |
390 | |
391 | spin_unlock(&cpuidle_driver_lock); | |
392 | } |