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Commit | Line | Data |
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4f86d3a8 LB |
1 | /* |
2 | * cpuidle.c - core cpuidle infrastructure | |
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/kernel.h> | |
12 | #include <linux/mutex.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/notifier.h> | |
d82b3518 | 15 | #include <linux/pm_qos_params.h> |
4f86d3a8 LB |
16 | #include <linux/cpu.h> |
17 | #include <linux/cpuidle.h> | |
9a0b8415 | 18 | #include <linux/ktime.h> |
2e94d1f7 | 19 | #include <linux/hrtimer.h> |
288f023e | 20 | #include <trace/events/power.h> |
4f86d3a8 LB |
21 | |
22 | #include "cpuidle.h" | |
23 | ||
24 | DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices); | |
4f86d3a8 LB |
25 | |
26 | DEFINE_MUTEX(cpuidle_lock); | |
27 | LIST_HEAD(cpuidle_detected_devices); | |
28 | static void (*pm_idle_old)(void); | |
29 | ||
30 | static int enabled_devices; | |
31 | ||
a6869cc4 VP |
32 | #if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT) |
33 | static void cpuidle_kick_cpus(void) | |
34 | { | |
35 | cpu_idle_wait(); | |
36 | } | |
37 | #elif defined(CONFIG_SMP) | |
38 | # error "Arch needs cpu_idle_wait() equivalent here" | |
39 | #else /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT && !CONFIG_SMP */ | |
40 | static void cpuidle_kick_cpus(void) {} | |
41 | #endif | |
42 | ||
dcb84f33 VP |
43 | static int __cpuidle_register_device(struct cpuidle_device *dev); |
44 | ||
4f86d3a8 LB |
45 | /** |
46 | * cpuidle_idle_call - the main idle loop | |
47 | * | |
48 | * NOTE: no locks or semaphores should be used here | |
49 | */ | |
50 | static void cpuidle_idle_call(void) | |
51 | { | |
52 | struct cpuidle_device *dev = __get_cpu_var(cpuidle_devices); | |
53 | struct cpuidle_state *target_state; | |
54 | int next_state; | |
55 | ||
56 | /* check if the device is ready */ | |
57 | if (!dev || !dev->enabled) { | |
58 | if (pm_idle_old) | |
59 | pm_idle_old(); | |
60 | else | |
89cedfef VP |
61 | #if defined(CONFIG_ARCH_HAS_DEFAULT_IDLE) |
62 | default_idle(); | |
63 | #else | |
4f86d3a8 | 64 | local_irq_enable(); |
89cedfef | 65 | #endif |
4f86d3a8 LB |
66 | return; |
67 | } | |
68 | ||
9a655837 AV |
69 | #if 0 |
70 | /* shows regressions, re-enable for 2.6.29 */ | |
2e94d1f7 AV |
71 | /* |
72 | * run any timers that can be run now, at this point | |
73 | * before calculating the idle duration etc. | |
74 | */ | |
75 | hrtimer_peek_ahead_timers(); | |
9a655837 | 76 | #endif |
71abbbf8 AL |
77 | |
78 | /* | |
79 | * Call the device's prepare function before calling the | |
80 | * governor's select function. ->prepare gives the device's | |
81 | * cpuidle driver a chance to update any dynamic information | |
82 | * of its cpuidle states for the current idle period, e.g. | |
83 | * state availability, latencies, residencies, etc. | |
84 | */ | |
85 | if (dev->prepare) | |
86 | dev->prepare(dev); | |
87 | ||
4f86d3a8 LB |
88 | /* ask the governor for the next state */ |
89 | next_state = cpuidle_curr_governor->select(dev); | |
246eb7f0 KH |
90 | if (need_resched()) { |
91 | local_irq_enable(); | |
4f86d3a8 | 92 | return; |
246eb7f0 KH |
93 | } |
94 | ||
4f86d3a8 LB |
95 | target_state = &dev->states[next_state]; |
96 | ||
97 | /* enter the state and update stats */ | |
4f86d3a8 | 98 | dev->last_state = target_state; |
887e301a VP |
99 | dev->last_residency = target_state->enter(dev, target_state); |
100 | if (dev->last_state) | |
101 | target_state = dev->last_state; | |
102 | ||
8b78cf60 | 103 | target_state->time += (unsigned long long)dev->last_residency; |
4f86d3a8 LB |
104 | target_state->usage++; |
105 | ||
106 | /* give the governor an opportunity to reflect on the outcome */ | |
107 | if (cpuidle_curr_governor->reflect) | |
108 | cpuidle_curr_governor->reflect(dev); | |
6f4f2723 | 109 | trace_power_end(smp_processor_id()); |
4f86d3a8 LB |
110 | } |
111 | ||
112 | /** | |
113 | * cpuidle_install_idle_handler - installs the cpuidle idle loop handler | |
114 | */ | |
115 | void cpuidle_install_idle_handler(void) | |
116 | { | |
117 | if (enabled_devices && (pm_idle != cpuidle_idle_call)) { | |
118 | /* Make sure all changes finished before we switch to new idle */ | |
119 | smp_wmb(); | |
120 | pm_idle = cpuidle_idle_call; | |
121 | } | |
122 | } | |
123 | ||
124 | /** | |
125 | * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler | |
126 | */ | |
127 | void cpuidle_uninstall_idle_handler(void) | |
128 | { | |
b032bf70 | 129 | if (enabled_devices && pm_idle_old && (pm_idle != pm_idle_old)) { |
4f86d3a8 | 130 | pm_idle = pm_idle_old; |
a6869cc4 | 131 | cpuidle_kick_cpus(); |
4f86d3a8 LB |
132 | } |
133 | } | |
134 | ||
135 | /** | |
136 | * cpuidle_pause_and_lock - temporarily disables CPUIDLE | |
137 | */ | |
138 | void cpuidle_pause_and_lock(void) | |
139 | { | |
140 | mutex_lock(&cpuidle_lock); | |
141 | cpuidle_uninstall_idle_handler(); | |
142 | } | |
143 | ||
144 | EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock); | |
145 | ||
146 | /** | |
147 | * cpuidle_resume_and_unlock - resumes CPUIDLE operation | |
148 | */ | |
149 | void cpuidle_resume_and_unlock(void) | |
150 | { | |
151 | cpuidle_install_idle_handler(); | |
152 | mutex_unlock(&cpuidle_lock); | |
153 | } | |
154 | ||
155 | EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); | |
156 | ||
d8c216cf RW |
157 | #ifdef CONFIG_ARCH_HAS_CPU_RELAX |
158 | static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st) | |
159 | { | |
160 | ktime_t t1, t2; | |
161 | s64 diff; | |
162 | int ret; | |
163 | ||
164 | t1 = ktime_get(); | |
165 | local_irq_enable(); | |
166 | while (!need_resched()) | |
167 | cpu_relax(); | |
168 | ||
169 | t2 = ktime_get(); | |
170 | diff = ktime_to_us(ktime_sub(t2, t1)); | |
171 | if (diff > INT_MAX) | |
172 | diff = INT_MAX; | |
173 | ||
174 | ret = (int) diff; | |
175 | return ret; | |
176 | } | |
177 | ||
178 | static void poll_idle_init(struct cpuidle_device *dev) | |
179 | { | |
180 | struct cpuidle_state *state = &dev->states[0]; | |
181 | ||
182 | cpuidle_set_statedata(state, NULL); | |
183 | ||
184 | snprintf(state->name, CPUIDLE_NAME_LEN, "C0"); | |
185 | snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); | |
186 | state->exit_latency = 0; | |
187 | state->target_residency = 0; | |
188 | state->power_usage = -1; | |
189 | state->flags = CPUIDLE_FLAG_POLL; | |
190 | state->enter = poll_idle; | |
191 | } | |
192 | #else | |
193 | static void poll_idle_init(struct cpuidle_device *dev) {} | |
194 | #endif /* CONFIG_ARCH_HAS_CPU_RELAX */ | |
195 | ||
4f86d3a8 LB |
196 | /** |
197 | * cpuidle_enable_device - enables idle PM for a CPU | |
198 | * @dev: the CPU | |
199 | * | |
200 | * This function must be called between cpuidle_pause_and_lock and | |
201 | * cpuidle_resume_and_unlock when used externally. | |
202 | */ | |
203 | int cpuidle_enable_device(struct cpuidle_device *dev) | |
204 | { | |
205 | int ret, i; | |
206 | ||
207 | if (dev->enabled) | |
208 | return 0; | |
752138df | 209 | if (!cpuidle_get_driver() || !cpuidle_curr_governor) |
4f86d3a8 LB |
210 | return -EIO; |
211 | if (!dev->state_count) | |
212 | return -EINVAL; | |
213 | ||
dcb84f33 VP |
214 | if (dev->registered == 0) { |
215 | ret = __cpuidle_register_device(dev); | |
216 | if (ret) | |
217 | return ret; | |
218 | } | |
219 | ||
d8c216cf RW |
220 | poll_idle_init(dev); |
221 | ||
4f86d3a8 LB |
222 | if ((ret = cpuidle_add_state_sysfs(dev))) |
223 | return ret; | |
224 | ||
225 | if (cpuidle_curr_governor->enable && | |
226 | (ret = cpuidle_curr_governor->enable(dev))) | |
227 | goto fail_sysfs; | |
228 | ||
229 | for (i = 0; i < dev->state_count; i++) { | |
230 | dev->states[i].usage = 0; | |
231 | dev->states[i].time = 0; | |
232 | } | |
233 | dev->last_residency = 0; | |
234 | dev->last_state = NULL; | |
235 | ||
236 | smp_wmb(); | |
237 | ||
238 | dev->enabled = 1; | |
239 | ||
240 | enabled_devices++; | |
241 | return 0; | |
242 | ||
243 | fail_sysfs: | |
244 | cpuidle_remove_state_sysfs(dev); | |
245 | ||
246 | return ret; | |
247 | } | |
248 | ||
249 | EXPORT_SYMBOL_GPL(cpuidle_enable_device); | |
250 | ||
251 | /** | |
252 | * cpuidle_disable_device - disables idle PM for a CPU | |
253 | * @dev: the CPU | |
254 | * | |
255 | * This function must be called between cpuidle_pause_and_lock and | |
256 | * cpuidle_resume_and_unlock when used externally. | |
257 | */ | |
258 | void cpuidle_disable_device(struct cpuidle_device *dev) | |
259 | { | |
260 | if (!dev->enabled) | |
261 | return; | |
752138df | 262 | if (!cpuidle_get_driver() || !cpuidle_curr_governor) |
4f86d3a8 LB |
263 | return; |
264 | ||
265 | dev->enabled = 0; | |
266 | ||
267 | if (cpuidle_curr_governor->disable) | |
268 | cpuidle_curr_governor->disable(dev); | |
269 | ||
270 | cpuidle_remove_state_sysfs(dev); | |
271 | enabled_devices--; | |
272 | } | |
273 | ||
274 | EXPORT_SYMBOL_GPL(cpuidle_disable_device); | |
275 | ||
276 | /** | |
dcb84f33 VP |
277 | * __cpuidle_register_device - internal register function called before register |
278 | * and enable routines | |
4f86d3a8 | 279 | * @dev: the cpu |
dcb84f33 VP |
280 | * |
281 | * cpuidle_lock mutex must be held before this is called | |
4f86d3a8 | 282 | */ |
dcb84f33 | 283 | static int __cpuidle_register_device(struct cpuidle_device *dev) |
4f86d3a8 LB |
284 | { |
285 | int ret; | |
286 | struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu); | |
752138df | 287 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 LB |
288 | |
289 | if (!sys_dev) | |
290 | return -EINVAL; | |
752138df | 291 | if (!try_module_get(cpuidle_driver->owner)) |
4f86d3a8 LB |
292 | return -EINVAL; |
293 | ||
294 | init_completion(&dev->kobj_unregister); | |
295 | ||
71abbbf8 AL |
296 | /* |
297 | * cpuidle driver should set the dev->power_specified bit | |
298 | * before registering the device if the driver provides | |
299 | * power_usage numbers. | |
300 | * | |
301 | * For those devices whose ->power_specified is not set, | |
302 | * we fill in power_usage with decreasing values as the | |
303 | * cpuidle code has an implicit assumption that state Cn | |
304 | * uses less power than C(n-1). | |
305 | * | |
306 | * With CONFIG_ARCH_HAS_CPU_RELAX, C0 is already assigned | |
307 | * an power value of -1. So we use -2, -3, etc, for other | |
308 | * c-states. | |
309 | */ | |
310 | if (!dev->power_specified) { | |
311 | int i; | |
312 | for (i = CPUIDLE_DRIVER_STATE_START; i < dev->state_count; i++) | |
313 | dev->states[i].power_usage = -1 - i; | |
314 | } | |
315 | ||
4f86d3a8 LB |
316 | per_cpu(cpuidle_devices, dev->cpu) = dev; |
317 | list_add(&dev->device_list, &cpuidle_detected_devices); | |
318 | if ((ret = cpuidle_add_sysfs(sys_dev))) { | |
752138df | 319 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
320 | return ret; |
321 | } | |
322 | ||
dcb84f33 VP |
323 | dev->registered = 1; |
324 | return 0; | |
325 | } | |
326 | ||
327 | /** | |
328 | * cpuidle_register_device - registers a CPU's idle PM feature | |
329 | * @dev: the cpu | |
330 | */ | |
331 | int cpuidle_register_device(struct cpuidle_device *dev) | |
332 | { | |
333 | int ret; | |
334 | ||
335 | mutex_lock(&cpuidle_lock); | |
336 | ||
337 | if ((ret = __cpuidle_register_device(dev))) { | |
338 | mutex_unlock(&cpuidle_lock); | |
339 | return ret; | |
340 | } | |
341 | ||
4f86d3a8 LB |
342 | cpuidle_enable_device(dev); |
343 | cpuidle_install_idle_handler(); | |
344 | ||
345 | mutex_unlock(&cpuidle_lock); | |
346 | ||
347 | return 0; | |
348 | ||
349 | } | |
350 | ||
351 | EXPORT_SYMBOL_GPL(cpuidle_register_device); | |
352 | ||
353 | /** | |
354 | * cpuidle_unregister_device - unregisters a CPU's idle PM feature | |
355 | * @dev: the cpu | |
356 | */ | |
357 | void cpuidle_unregister_device(struct cpuidle_device *dev) | |
358 | { | |
359 | struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu); | |
752138df | 360 | struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver(); |
4f86d3a8 | 361 | |
dcb84f33 VP |
362 | if (dev->registered == 0) |
363 | return; | |
364 | ||
4f86d3a8 LB |
365 | cpuidle_pause_and_lock(); |
366 | ||
367 | cpuidle_disable_device(dev); | |
368 | ||
369 | cpuidle_remove_sysfs(sys_dev); | |
370 | list_del(&dev->device_list); | |
371 | wait_for_completion(&dev->kobj_unregister); | |
372 | per_cpu(cpuidle_devices, dev->cpu) = NULL; | |
373 | ||
374 | cpuidle_resume_and_unlock(); | |
375 | ||
752138df | 376 | module_put(cpuidle_driver->owner); |
4f86d3a8 LB |
377 | } |
378 | ||
379 | EXPORT_SYMBOL_GPL(cpuidle_unregister_device); | |
380 | ||
381 | #ifdef CONFIG_SMP | |
382 | ||
383 | static void smp_callback(void *v) | |
384 | { | |
385 | /* we already woke the CPU up, nothing more to do */ | |
386 | } | |
387 | ||
388 | /* | |
389 | * This function gets called when a part of the kernel has a new latency | |
390 | * requirement. This means we need to get all processors out of their C-state, | |
391 | * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that | |
392 | * wakes them all right up. | |
393 | */ | |
394 | static int cpuidle_latency_notify(struct notifier_block *b, | |
395 | unsigned long l, void *v) | |
396 | { | |
8691e5a8 | 397 | smp_call_function(smp_callback, NULL, 1); |
4f86d3a8 LB |
398 | return NOTIFY_OK; |
399 | } | |
400 | ||
401 | static struct notifier_block cpuidle_latency_notifier = { | |
402 | .notifier_call = cpuidle_latency_notify, | |
403 | }; | |
404 | ||
d82b3518 MG |
405 | static inline void latency_notifier_init(struct notifier_block *n) |
406 | { | |
407 | pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n); | |
408 | } | |
4f86d3a8 LB |
409 | |
410 | #else /* CONFIG_SMP */ | |
411 | ||
412 | #define latency_notifier_init(x) do { } while (0) | |
413 | ||
414 | #endif /* CONFIG_SMP */ | |
415 | ||
416 | /** | |
417 | * cpuidle_init - core initializer | |
418 | */ | |
419 | static int __init cpuidle_init(void) | |
420 | { | |
421 | int ret; | |
422 | ||
423 | pm_idle_old = pm_idle; | |
424 | ||
425 | ret = cpuidle_add_class_sysfs(&cpu_sysdev_class); | |
426 | if (ret) | |
427 | return ret; | |
428 | ||
429 | latency_notifier_init(&cpuidle_latency_notifier); | |
430 | ||
431 | return 0; | |
432 | } | |
433 | ||
434 | core_initcall(cpuidle_init); |