blob: e431d11abf8d86deb79b200ef17eaa24a2c139ca [file] [log] [blame]
Len Brown4f86d3a2007-10-03 18:58:00 -04001/*
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>
Viresh Kumard7c7f102013-10-03 21:26:54 +053013#include <linux/sched.h>
Len Brown4f86d3a2007-10-03 18:58:00 -040014#include <linux/cpuidle.h>
Daniel Lezcanoa06df062013-03-27 10:22:10 +000015#include <linux/cpumask.h>
16#include <linux/clockchips.h>
Len Brown4f86d3a2007-10-03 18:58:00 -040017
18#include "cpuidle.h"
19
Len Brown4f86d3a2007-10-03 18:58:00 -040020DEFINE_SPINLOCK(cpuidle_driver_lock);
21
Daniel Lezcano82467a52013-06-07 21:53:09 +000022#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
23
24static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers);
25
Daniel Lezcano6d19cb92013-06-07 21:53:10 +000026/**
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 */
Daniel Lezcano82467a52013-06-07 21:53:09 +000033static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
34{
35 return per_cpu(cpuidle_drivers, cpu);
36}
37
Daniel Lezcano6d19cb92013-06-07 21:53:10 +000038/**
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 */
Daniel Lezcano82467a52013-06-07 21:53:09 +000046static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv)
47{
48 int cpu;
49
50 for_each_cpu(cpu, drv->cpumask) {
51
52 if (drv != __cpuidle_get_cpu_driver(cpu))
53 continue;
54
55 per_cpu(cpuidle_drivers, cpu) = NULL;
56 }
57}
58
Daniel Lezcano6d19cb92013-06-07 21:53:10 +000059/**
Viresh Kumarcaf4a362013-10-03 21:26:41 +053060 * __cpuidle_set_driver - set per CPU driver variables for the given driver.
Daniel Lezcano6d19cb92013-06-07 21:53:10 +000061 * @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 */
Daniel Lezcano82467a52013-06-07 21:53:09 +000068static inline int __cpuidle_set_driver(struct cpuidle_driver *drv)
69{
70 int cpu;
71
72 for_each_cpu(cpu, drv->cpumask) {
73
74 if (__cpuidle_get_cpu_driver(cpu)) {
75 __cpuidle_unset_driver(drv);
76 return -EBUSY;
77 }
78
79 per_cpu(cpuidle_drivers, cpu) = drv;
80 }
81
82 return 0;
83}
84
85#else
86
87static struct cpuidle_driver *cpuidle_curr_driver;
88
Daniel Lezcano6d19cb92013-06-07 21:53:10 +000089/**
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 */
Daniel Lezcano82467a52013-06-07 21:53:09 +000096static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
97{
98 return cpuidle_curr_driver;
99}
100
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000101/**
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 */
Daniel Lezcano82467a52013-06-07 21:53:09 +0000107static inline int __cpuidle_set_driver(struct cpuidle_driver *drv)
108{
109 if (cpuidle_curr_driver)
110 return -EBUSY;
111
112 cpuidle_curr_driver = drv;
113
114 return 0;
115}
116
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000117/**
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 */
Daniel Lezcano82467a52013-06-07 21:53:09 +0000124static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv)
125{
126 if (drv == cpuidle_curr_driver)
127 cpuidle_curr_driver = NULL;
128}
129
130#endif
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000131
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000132/**
133 * cpuidle_setup_broadcast_timer - enable/disable the broadcast timer
134 * @arg: a void pointer used to match the SMP cross call API
135 *
Viresh Kumarcaf4a362013-10-03 21:26:41 +0530136 * @arg is used as a value of type 'long' with one of the two values:
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000137 * - 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 */
Daniel Lezcanoa06df062013-03-27 10:22:10 +0000144static void cpuidle_setup_broadcast_timer(void *arg)
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000145{
Daniel Lezcanoa06df062013-03-27 10:22:10 +0000146 int cpu = smp_processor_id();
147 clockevents_notify((long)(arg), &cpu);
148}
149
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000150/**
151 * __cpuidle_driver_init - initialize the driver's internal data
152 * @drv: a valid pointer to a struct cpuidle_driver
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000153 */
Viresh Kumare437f3e2013-10-03 21:26:44 +0530154static void __cpuidle_driver_init(struct cpuidle_driver *drv)
Daniel Lezcanoa06df062013-03-27 10:22:10 +0000155{
156 int i;
157
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000158 drv->refcnt = 0;
Daniel Lezcanoa06df062013-03-27 10:22:10 +0000159
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000160 /*
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 */
Daniel Lezcano82467a52013-06-07 21:53:09 +0000165 if (!drv->cpumask)
166 drv->cpumask = (struct cpumask *)cpu_possible_mask;
167
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000168 /*
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
Viresh Kumarcaf4a362013-10-03 21:26:41 +0530171 * order, because usually one of the deeper states have this flag set.
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000172 */
Daniel Lezcanoa06df062013-03-27 10:22:10 +0000173 for (i = drv->state_count - 1; i >= 0 ; i--) {
Viresh Kumarb171a852013-10-03 21:26:45 +0530174 if (drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP) {
175 drv->bctimer = 1;
176 break;
177 }
Daniel Lezcanoa06df062013-03-27 10:22:10 +0000178 }
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000179}
180
Viresh Kumard7c7f102013-10-03 21:26:54 +0530181#ifdef CONFIG_ARCH_HAS_CPU_RELAX
182static int poll_idle(struct cpuidle_device *dev,
183 struct cpuidle_driver *drv, int index)
184{
Viresh Kumard7c7f102013-10-03 21:26:54 +0530185 local_irq_enable();
Andy Lutomirski84c40702014-06-04 10:31:14 -0700186 if (!current_set_polling_and_test()) {
187 while (!need_resched())
188 cpu_relax();
189 }
190 current_clr_polling();
Viresh Kumard7c7f102013-10-03 21:26:54 +0530191
Viresh Kumard7c7f102013-10-03 21:26:54 +0530192 return index;
193}
194
195static void poll_idle_init(struct cpuidle_driver *drv)
196{
197 struct cpuidle_state *state = &drv->states[0];
198
199 snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
200 snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
201 state->exit_latency = 0;
202 state->target_residency = 0;
203 state->power_usage = -1;
tuukka.tikkanen@linaro.org4b2f0b02014-02-24 08:29:37 +0200204 state->flags = CPUIDLE_FLAG_TIME_VALID;
Viresh Kumard7c7f102013-10-03 21:26:54 +0530205 state->enter = poll_idle;
206 state->disabled = false;
207}
208#else
209static void poll_idle_init(struct cpuidle_driver *drv) {}
210#endif /* !CONFIG_ARCH_HAS_CPU_RELAX */
211
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000212/**
213 * __cpuidle_register_driver: register the driver
214 * @drv: a valid pointer to a struct cpuidle_driver
215 *
216 * Do some sanity checks, initialize the driver, assign the driver to the
217 * global cpuidle driver variable(s) and set up the broadcast timer if the
218 * cpuidle driver has some states that shut down the local timer.
219 *
220 * Returns 0 on success, a negative error code otherwise:
221 * * -EINVAL if the driver pointer is NULL or no idle states are available
222 * * -ENODEV if the cpuidle framework is disabled
223 * * -EBUSY if the driver is already assigned to the global variable(s)
224 */
Daniel Lezcano82467a52013-06-07 21:53:09 +0000225static int __cpuidle_register_driver(struct cpuidle_driver *drv)
Len Brown4f86d3a2007-10-03 18:58:00 -0400226{
Daniel Lezcano82467a52013-06-07 21:53:09 +0000227 int ret;
228
Daniel Lezcanofc850f32012-03-26 14:51:26 +0200229 if (!drv || !drv->state_count)
Len Brown4f86d3a2007-10-03 18:58:00 -0400230 return -EINVAL;
231
Len Brown62027ae2011-04-01 18:13:10 -0400232 if (cpuidle_disabled())
233 return -ENODEV;
234
Viresh Kumare437f3e2013-10-03 21:26:44 +0530235 __cpuidle_driver_init(drv);
Daniel Lezcanoed953472012-09-22 00:38:32 +0200236
Daniel Lezcano82467a52013-06-07 21:53:09 +0000237 ret = __cpuidle_set_driver(drv);
238 if (ret)
239 return ret;
Daniel Lezcanoed953472012-09-22 00:38:32 +0200240
Daniel Lezcano82467a52013-06-07 21:53:09 +0000241 if (drv->bctimer)
242 on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer,
243 (void *)CLOCK_EVT_NOTIFY_BROADCAST_ON, 1);
Len Brown4f86d3a2007-10-03 18:58:00 -0400244
Viresh Kumard7c7f102013-10-03 21:26:54 +0530245 poll_idle_init(drv);
246
Len Brown4f86d3a2007-10-03 18:58:00 -0400247 return 0;
248}
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000249
Daniel Lezcano82467a52013-06-07 21:53:09 +0000250/**
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000251 * __cpuidle_unregister_driver - unregister the driver
252 * @drv: a valid pointer to a struct cpuidle_driver
253 *
254 * Check if the driver is no longer in use, reset the global cpuidle driver
255 * variable(s) and disable the timer broadcast notification mechanism if it was
256 * in use.
257 *
Daniel Lezcano82467a52013-06-07 21:53:09 +0000258 */
259static void __cpuidle_unregister_driver(struct cpuidle_driver *drv)
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000260{
Daniel Lezcano82467a52013-06-07 21:53:09 +0000261 if (WARN_ON(drv->refcnt > 0))
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000262 return;
263
Daniel Lezcanoa06df062013-03-27 10:22:10 +0000264 if (drv->bctimer) {
265 drv->bctimer = 0;
Daniel Lezcano82467a52013-06-07 21:53:09 +0000266 on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer,
Daniel Lezcanoa06df062013-03-27 10:22:10 +0000267 (void *)CLOCK_EVT_NOTIFY_BROADCAST_OFF, 1);
268 }
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000269
Daniel Lezcano82467a52013-06-07 21:53:09 +0000270 __cpuidle_unset_driver(drv);
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000271}
272
273/**
274 * cpuidle_register_driver - registers a driver
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000275 * @drv: a pointer to a valid struct cpuidle_driver
276 *
277 * Register the driver under a lock to prevent concurrent attempts to
278 * [un]register the driver from occuring at the same time.
279 *
280 * Returns 0 on success, a negative error code (returned by
281 * __cpuidle_register_driver()) otherwise.
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000282 */
283int cpuidle_register_driver(struct cpuidle_driver *drv)
284{
285 int ret;
286
287 spin_lock(&cpuidle_driver_lock);
Daniel Lezcano82467a52013-06-07 21:53:09 +0000288 ret = __cpuidle_register_driver(drv);
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000289 spin_unlock(&cpuidle_driver_lock);
290
291 return ret;
292}
Len Brown4f86d3a2007-10-03 18:58:00 -0400293EXPORT_SYMBOL_GPL(cpuidle_register_driver);
294
295/**
296 * cpuidle_unregister_driver - unregisters a driver
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000297 * @drv: a pointer to a valid struct cpuidle_driver
298 *
299 * Unregisters the cpuidle driver under a lock to prevent concurrent attempts
300 * to [un]register the driver from occuring at the same time. @drv has to
301 * match the currently registered driver.
Len Brown4f86d3a2007-10-03 18:58:00 -0400302 */
303void cpuidle_unregister_driver(struct cpuidle_driver *drv)
304{
Len Brown4f86d3a2007-10-03 18:58:00 -0400305 spin_lock(&cpuidle_driver_lock);
Daniel Lezcano82467a52013-06-07 21:53:09 +0000306 __cpuidle_unregister_driver(drv);
Len Brown4f86d3a2007-10-03 18:58:00 -0400307 spin_unlock(&cpuidle_driver_lock);
308}
Len Brown4f86d3a2007-10-03 18:58:00 -0400309EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
Rafael J. Wysocki6e797a02012-06-16 15:20:11 +0200310
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000311/**
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000312 * cpuidle_get_driver - return the driver tied to the current CPU.
313 *
314 * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered.
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000315 */
316struct cpuidle_driver *cpuidle_get_driver(void)
317{
318 struct cpuidle_driver *drv;
319 int cpu;
320
321 cpu = get_cpu();
322 drv = __cpuidle_get_cpu_driver(cpu);
323 put_cpu();
324
325 return drv;
326}
327EXPORT_SYMBOL_GPL(cpuidle_get_driver);
328
329/**
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000330 * cpuidle_get_cpu_driver - return the driver registered for a CPU.
331 * @dev: a valid pointer to a struct cpuidle_device
332 *
333 * Returns a struct cpuidle_driver pointer, or NULL if no driver is registered
334 * for the CPU associated with @dev.
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000335 */
336struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
337{
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000338 if (!dev)
339 return NULL;
340
Daniel Lezcanoac34d7c2013-01-03 13:03:18 +0100341 return __cpuidle_get_cpu_driver(dev->cpu);
Daniel Lezcanobf4d1b52012-10-31 16:44:48 +0000342}
343EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver);
344
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000345/**
346 * cpuidle_driver_ref - get a reference to the driver.
347 *
348 * Increment the reference counter of the cpuidle driver associated with
349 * the current CPU.
350 *
351 * Returns a pointer to the driver, or NULL if the current CPU has no driver.
352 */
Rafael J. Wysocki6e797a02012-06-16 15:20:11 +0200353struct cpuidle_driver *cpuidle_driver_ref(void)
354{
355 struct cpuidle_driver *drv;
356
357 spin_lock(&cpuidle_driver_lock);
358
Daniel Lezcano13dd52f2012-10-31 16:44:47 +0000359 drv = cpuidle_get_driver();
Daniel Fu3b9c10e2013-08-30 19:48:22 +0800360 if (drv)
361 drv->refcnt++;
Rafael J. Wysocki6e797a02012-06-16 15:20:11 +0200362
363 spin_unlock(&cpuidle_driver_lock);
364 return drv;
365}
366
Daniel Lezcano6d19cb92013-06-07 21:53:10 +0000367/**
368 * cpuidle_driver_unref - puts down the refcount for the driver
369 *
370 * Decrement the reference counter of the cpuidle driver associated with
371 * the current CPU.
372 */
Rafael J. Wysocki6e797a02012-06-16 15:20:11 +0200373void cpuidle_driver_unref(void)
374{
Viresh Kumar0d09d312013-10-03 21:26:50 +0530375 struct cpuidle_driver *drv;
Daniel Lezcano42f67f22012-10-31 16:44:45 +0000376
Rafael J. Wysocki6e797a02012-06-16 15:20:11 +0200377 spin_lock(&cpuidle_driver_lock);
378
Viresh Kumar0d09d312013-10-03 21:26:50 +0530379 drv = cpuidle_get_driver();
Daniel Lezcano42f67f22012-10-31 16:44:45 +0000380 if (drv && !WARN_ON(drv->refcnt <= 0))
381 drv->refcnt--;
Rafael J. Wysocki6e797a02012-06-16 15:20:11 +0200382
383 spin_unlock(&cpuidle_driver_lock);
384}