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1da177e4 LT |
1 | /* |
2 | * drivers/cpufreq/cpufreq_ondemand.c | |
3 | * | |
4 | * Copyright (C) 2001 Russell King | |
5 | * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>. | |
6 | * Jun Nakajima <jun.nakajima@intel.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/kernel.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/smp.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/ctype.h> | |
19 | #include <linux/cpufreq.h> | |
20 | #include <linux/sysctl.h> | |
21 | #include <linux/types.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/sysfs.h> | |
24 | #include <linux/sched.h> | |
25 | #include <linux/kmod.h> | |
26 | #include <linux/workqueue.h> | |
27 | #include <linux/jiffies.h> | |
28 | #include <linux/kernel_stat.h> | |
29 | #include <linux/percpu.h> | |
3fc54d37 | 30 | #include <linux/mutex.h> |
1da177e4 LT |
31 | |
32 | /* | |
33 | * dbs is used in this file as a shortform for demandbased switching | |
34 | * It helps to keep variable names smaller, simpler | |
35 | */ | |
36 | ||
37 | #define DEF_FREQUENCY_UP_THRESHOLD (80) | |
c29f1403 | 38 | #define MIN_FREQUENCY_UP_THRESHOLD (11) |
1da177e4 LT |
39 | #define MAX_FREQUENCY_UP_THRESHOLD (100) |
40 | ||
32ee8c3e DJ |
41 | /* |
42 | * The polling frequency of this governor depends on the capability of | |
1da177e4 | 43 | * the processor. Default polling frequency is 1000 times the transition |
32ee8c3e DJ |
44 | * latency of the processor. The governor will work on any processor with |
45 | * transition latency <= 10mS, using appropriate sampling | |
1da177e4 LT |
46 | * rate. |
47 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) | |
48 | * this governor will not work. | |
49 | * All times here are in uS. | |
50 | */ | |
32ee8c3e | 51 | static unsigned int def_sampling_rate; |
df8b59be DJ |
52 | #define MIN_SAMPLING_RATE_RATIO (2) |
53 | /* for correct statistics, we need at least 10 ticks between each measure */ | |
54 | #define MIN_STAT_SAMPLING_RATE (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) | |
55 | #define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) | |
1da177e4 LT |
56 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
57 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) | |
e131832c DJ |
58 | #define DEF_SAMPLING_DOWN_FACTOR (1) |
59 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
1da177e4 | 60 | #define TRANSITION_LATENCY_LIMIT (10 * 1000) |
1da177e4 LT |
61 | |
62 | static void do_dbs_timer(void *data); | |
63 | ||
64 | struct cpu_dbs_info_s { | |
32ee8c3e DJ |
65 | struct cpufreq_policy *cur_policy; |
66 | unsigned int prev_cpu_idle_up; | |
67 | unsigned int prev_cpu_idle_down; | |
68 | unsigned int enable; | |
1da177e4 LT |
69 | }; |
70 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); | |
71 | ||
72 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
73 | ||
32ee8c3e | 74 | static DEFINE_MUTEX (dbs_mutex); |
1da177e4 LT |
75 | static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); |
76 | ||
6810b548 AK |
77 | static struct workqueue_struct *dbs_workq; |
78 | ||
1da177e4 | 79 | struct dbs_tuners { |
32ee8c3e DJ |
80 | unsigned int sampling_rate; |
81 | unsigned int sampling_down_factor; | |
82 | unsigned int up_threshold; | |
83 | unsigned int ignore_nice; | |
1da177e4 LT |
84 | }; |
85 | ||
86 | static struct dbs_tuners dbs_tuners_ins = { | |
32ee8c3e DJ |
87 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
88 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
9cbad61b | 89 | .ignore_nice = 0, |
1da177e4 LT |
90 | }; |
91 | ||
dac1c1a5 DJ |
92 | static inline unsigned int get_cpu_idle_time(unsigned int cpu) |
93 | { | |
94 | return kstat_cpu(cpu).cpustat.idle + | |
95 | kstat_cpu(cpu).cpustat.iowait + | |
001893cd | 96 | ( dbs_tuners_ins.ignore_nice ? |
dac1c1a5 DJ |
97 | kstat_cpu(cpu).cpustat.nice : |
98 | 0); | |
99 | } | |
100 | ||
1da177e4 LT |
101 | /************************** sysfs interface ************************/ |
102 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
103 | { | |
104 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); | |
105 | } | |
106 | ||
107 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
108 | { | |
109 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); | |
110 | } | |
111 | ||
32ee8c3e DJ |
112 | #define define_one_ro(_name) \ |
113 | static struct freq_attr _name = \ | |
1da177e4 LT |
114 | __ATTR(_name, 0444, show_##_name, NULL) |
115 | ||
116 | define_one_ro(sampling_rate_max); | |
117 | define_one_ro(sampling_rate_min); | |
118 | ||
119 | /* cpufreq_ondemand Governor Tunables */ | |
120 | #define show_one(file_name, object) \ | |
121 | static ssize_t show_##file_name \ | |
122 | (struct cpufreq_policy *unused, char *buf) \ | |
123 | { \ | |
124 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
125 | } | |
126 | show_one(sampling_rate, sampling_rate); | |
127 | show_one(sampling_down_factor, sampling_down_factor); | |
128 | show_one(up_threshold, up_threshold); | |
001893cd | 129 | show_one(ignore_nice_load, ignore_nice); |
1da177e4 | 130 | |
32ee8c3e | 131 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, |
1da177e4 LT |
132 | const char *buf, size_t count) |
133 | { | |
134 | unsigned int input; | |
135 | int ret; | |
136 | ret = sscanf (buf, "%u", &input); | |
137 | if (ret != 1 ) | |
138 | return -EINVAL; | |
139 | ||
e131832c DJ |
140 | if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
141 | return -EINVAL; | |
142 | ||
3fc54d37 | 143 | mutex_lock(&dbs_mutex); |
1da177e4 | 144 | dbs_tuners_ins.sampling_down_factor = input; |
3fc54d37 | 145 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
146 | |
147 | return count; | |
148 | } | |
149 | ||
32ee8c3e | 150 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
1da177e4 LT |
151 | const char *buf, size_t count) |
152 | { | |
153 | unsigned int input; | |
154 | int ret; | |
155 | ret = sscanf (buf, "%u", &input); | |
156 | ||
3fc54d37 | 157 | mutex_lock(&dbs_mutex); |
1da177e4 | 158 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
3fc54d37 | 159 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
160 | return -EINVAL; |
161 | } | |
162 | ||
163 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 164 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
165 | |
166 | return count; | |
167 | } | |
168 | ||
32ee8c3e | 169 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
1da177e4 LT |
170 | const char *buf, size_t count) |
171 | { | |
172 | unsigned int input; | |
173 | int ret; | |
174 | ret = sscanf (buf, "%u", &input); | |
175 | ||
3fc54d37 | 176 | mutex_lock(&dbs_mutex); |
32ee8c3e | 177 | if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || |
c29f1403 | 178 | input < MIN_FREQUENCY_UP_THRESHOLD) { |
3fc54d37 | 179 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
180 | return -EINVAL; |
181 | } | |
182 | ||
183 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 184 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
185 | |
186 | return count; | |
187 | } | |
188 | ||
001893cd | 189 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
3d5ee9e5 DJ |
190 | const char *buf, size_t count) |
191 | { | |
192 | unsigned int input; | |
193 | int ret; | |
194 | ||
195 | unsigned int j; | |
32ee8c3e | 196 | |
3d5ee9e5 DJ |
197 | ret = sscanf (buf, "%u", &input); |
198 | if ( ret != 1 ) | |
199 | return -EINVAL; | |
200 | ||
201 | if ( input > 1 ) | |
202 | input = 1; | |
32ee8c3e | 203 | |
3fc54d37 | 204 | mutex_lock(&dbs_mutex); |
3d5ee9e5 | 205 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
3fc54d37 | 206 | mutex_unlock(&dbs_mutex); |
3d5ee9e5 DJ |
207 | return count; |
208 | } | |
209 | dbs_tuners_ins.ignore_nice = input; | |
210 | ||
211 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
dac1c1a5 | 212 | for_each_online_cpu(j) { |
3d5ee9e5 DJ |
213 | struct cpu_dbs_info_s *j_dbs_info; |
214 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
dac1c1a5 | 215 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
3d5ee9e5 DJ |
216 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
217 | } | |
3fc54d37 | 218 | mutex_unlock(&dbs_mutex); |
3d5ee9e5 DJ |
219 | |
220 | return count; | |
221 | } | |
222 | ||
1da177e4 LT |
223 | #define define_one_rw(_name) \ |
224 | static struct freq_attr _name = \ | |
225 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
226 | ||
227 | define_one_rw(sampling_rate); | |
228 | define_one_rw(sampling_down_factor); | |
229 | define_one_rw(up_threshold); | |
001893cd | 230 | define_one_rw(ignore_nice_load); |
1da177e4 LT |
231 | |
232 | static struct attribute * dbs_attributes[] = { | |
233 | &sampling_rate_max.attr, | |
234 | &sampling_rate_min.attr, | |
235 | &sampling_rate.attr, | |
236 | &sampling_down_factor.attr, | |
237 | &up_threshold.attr, | |
001893cd | 238 | &ignore_nice_load.attr, |
1da177e4 LT |
239 | NULL |
240 | }; | |
241 | ||
242 | static struct attribute_group dbs_attr_group = { | |
243 | .attrs = dbs_attributes, | |
244 | .name = "ondemand", | |
245 | }; | |
246 | ||
247 | /************************** sysfs end ************************/ | |
248 | ||
249 | static void dbs_check_cpu(int cpu) | |
250 | { | |
c29f1403 DJ |
251 | unsigned int idle_ticks, up_idle_ticks, total_ticks; |
252 | unsigned int freq_next; | |
1da177e4 LT |
253 | unsigned int freq_down_sampling_rate; |
254 | static int down_skip[NR_CPUS]; | |
255 | struct cpu_dbs_info_s *this_dbs_info; | |
256 | ||
257 | struct cpufreq_policy *policy; | |
258 | unsigned int j; | |
259 | ||
260 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
261 | if (!this_dbs_info->enable) | |
262 | return; | |
263 | ||
264 | policy = this_dbs_info->cur_policy; | |
32ee8c3e | 265 | /* |
c29f1403 DJ |
266 | * Every sampling_rate, we check, if current idle time is less |
267 | * than 20% (default), then we try to increase frequency | |
268 | * Every sampling_rate*sampling_down_factor, we look for a the lowest | |
269 | * frequency which can sustain the load while keeping idle time over | |
270 | * 30%. If such a frequency exist, we try to decrease to this frequency. | |
1da177e4 | 271 | * |
32ee8c3e DJ |
272 | * Any frequency increase takes it to the maximum frequency. |
273 | * Frequency reduction happens at minimum steps of | |
274 | * 5% (default) of current frequency | |
1da177e4 LT |
275 | */ |
276 | ||
277 | /* Check for frequency increase */ | |
9c7d269b | 278 | idle_ticks = UINT_MAX; |
1da177e4 | 279 | for_each_cpu_mask(j, policy->cpus) { |
9c7d269b | 280 | unsigned int tmp_idle_ticks, total_idle_ticks; |
1da177e4 LT |
281 | struct cpu_dbs_info_s *j_dbs_info; |
282 | ||
1da177e4 | 283 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
dac1c1a5 | 284 | total_idle_ticks = get_cpu_idle_time(j); |
1da177e4 LT |
285 | tmp_idle_ticks = total_idle_ticks - |
286 | j_dbs_info->prev_cpu_idle_up; | |
287 | j_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
288 | ||
289 | if (tmp_idle_ticks < idle_ticks) | |
290 | idle_ticks = tmp_idle_ticks; | |
291 | } | |
292 | ||
293 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
294 | idle_ticks *= 100; | |
295 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
6fe71165 | 296 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
1da177e4 LT |
297 | |
298 | if (idle_ticks < up_idle_ticks) { | |
dac1c1a5 | 299 | down_skip[cpu] = 0; |
790d76fa DJ |
300 | for_each_cpu_mask(j, policy->cpus) { |
301 | struct cpu_dbs_info_s *j_dbs_info; | |
302 | ||
303 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
32ee8c3e | 304 | j_dbs_info->prev_cpu_idle_down = |
790d76fa DJ |
305 | j_dbs_info->prev_cpu_idle_up; |
306 | } | |
c11420a6 DJ |
307 | /* if we are already at full speed then break out early */ |
308 | if (policy->cur == policy->max) | |
309 | return; | |
32ee8c3e DJ |
310 | |
311 | __cpufreq_driver_target(policy, policy->max, | |
1da177e4 | 312 | CPUFREQ_RELATION_H); |
1da177e4 LT |
313 | return; |
314 | } | |
315 | ||
316 | /* Check for frequency decrease */ | |
317 | down_skip[cpu]++; | |
318 | if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor) | |
319 | return; | |
320 | ||
9c7d269b | 321 | idle_ticks = UINT_MAX; |
1da177e4 | 322 | for_each_cpu_mask(j, policy->cpus) { |
9c7d269b | 323 | unsigned int tmp_idle_ticks, total_idle_ticks; |
1da177e4 LT |
324 | struct cpu_dbs_info_s *j_dbs_info; |
325 | ||
1da177e4 | 326 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
dac1c1a5 DJ |
327 | /* Check for frequency decrease */ |
328 | total_idle_ticks = j_dbs_info->prev_cpu_idle_up; | |
1da177e4 LT |
329 | tmp_idle_ticks = total_idle_ticks - |
330 | j_dbs_info->prev_cpu_idle_down; | |
331 | j_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
332 | ||
333 | if (tmp_idle_ticks < idle_ticks) | |
334 | idle_ticks = tmp_idle_ticks; | |
335 | } | |
336 | ||
1da177e4 | 337 | down_skip[cpu] = 0; |
c29f1403 DJ |
338 | /* if we cannot reduce the frequency anymore, break out early */ |
339 | if (policy->cur == policy->min) | |
340 | return; | |
1da177e4 | 341 | |
c29f1403 | 342 | /* Compute how many ticks there are between two measurements */ |
1da177e4 LT |
343 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * |
344 | dbs_tuners_ins.sampling_down_factor; | |
c29f1403 | 345 | total_ticks = usecs_to_jiffies(freq_down_sampling_rate); |
1206aaac | 346 | |
c29f1403 DJ |
347 | /* |
348 | * The optimal frequency is the frequency that is the lowest that | |
349 | * can support the current CPU usage without triggering the up | |
350 | * policy. To be safe, we focus 10 points under the threshold. | |
351 | */ | |
352 | freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks; | |
32ee8c3e | 353 | freq_next = (freq_next * policy->cur) / |
c29f1403 | 354 | (dbs_tuners_ins.up_threshold - 10); |
1da177e4 | 355 | |
7c9d8c0e DB |
356 | if (freq_next < policy->min) |
357 | freq_next = policy->min; | |
358 | ||
c29f1403 DJ |
359 | if (freq_next <= ((policy->cur * 95) / 100)) |
360 | __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L); | |
1da177e4 LT |
361 | } |
362 | ||
363 | static void do_dbs_timer(void *data) | |
32ee8c3e | 364 | { |
1da177e4 | 365 | int i; |
3fc54d37 | 366 | mutex_lock(&dbs_mutex); |
6fe71165 DJ |
367 | for_each_online_cpu(i) |
368 | dbs_check_cpu(i); | |
6810b548 AK |
369 | queue_delayed_work(dbs_workq, &dbs_work, |
370 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
3fc54d37 | 371 | mutex_unlock(&dbs_mutex); |
32ee8c3e | 372 | } |
1da177e4 LT |
373 | |
374 | static inline void dbs_timer_init(void) | |
375 | { | |
376 | INIT_WORK(&dbs_work, do_dbs_timer, NULL); | |
6810b548 AK |
377 | if (!dbs_workq) |
378 | dbs_workq = create_singlethread_workqueue("ondemand"); | |
379 | if (!dbs_workq) { | |
380 | printk(KERN_ERR "ondemand: Cannot initialize kernel thread\n"); | |
381 | return; | |
382 | } | |
383 | queue_delayed_work(dbs_workq, &dbs_work, | |
384 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
1da177e4 LT |
385 | return; |
386 | } | |
387 | ||
388 | static inline void dbs_timer_exit(void) | |
389 | { | |
6810b548 AK |
390 | if (dbs_workq) |
391 | cancel_rearming_delayed_workqueue(dbs_workq, &dbs_work); | |
1da177e4 LT |
392 | } |
393 | ||
394 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
395 | unsigned int event) | |
396 | { | |
397 | unsigned int cpu = policy->cpu; | |
398 | struct cpu_dbs_info_s *this_dbs_info; | |
399 | unsigned int j; | |
400 | ||
401 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
402 | ||
403 | switch (event) { | |
404 | case CPUFREQ_GOV_START: | |
32ee8c3e | 405 | if ((!cpu_online(cpu)) || |
1da177e4 LT |
406 | (!policy->cur)) |
407 | return -EINVAL; | |
408 | ||
409 | if (policy->cpuinfo.transition_latency > | |
ff8c288d EP |
410 | (TRANSITION_LATENCY_LIMIT * 1000)) { |
411 | printk(KERN_WARNING "ondemand governor failed to load " | |
412 | "due to too long transition latency\n"); | |
1da177e4 | 413 | return -EINVAL; |
ff8c288d | 414 | } |
1da177e4 LT |
415 | if (this_dbs_info->enable) /* Already enabled */ |
416 | break; | |
32ee8c3e | 417 | |
3fc54d37 | 418 | mutex_lock(&dbs_mutex); |
1da177e4 LT |
419 | for_each_cpu_mask(j, policy->cpus) { |
420 | struct cpu_dbs_info_s *j_dbs_info; | |
421 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
422 | j_dbs_info->cur_policy = policy; | |
32ee8c3e | 423 | |
dac1c1a5 | 424 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
3d5ee9e5 DJ |
425 | j_dbs_info->prev_cpu_idle_down |
426 | = j_dbs_info->prev_cpu_idle_up; | |
1da177e4 LT |
427 | } |
428 | this_dbs_info->enable = 1; | |
429 | sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
430 | dbs_enable++; | |
431 | /* | |
432 | * Start the timerschedule work, when this governor | |
433 | * is used for first time | |
434 | */ | |
435 | if (dbs_enable == 1) { | |
436 | unsigned int latency; | |
437 | /* policy latency is in nS. Convert it to uS first */ | |
df8b59be DJ |
438 | latency = policy->cpuinfo.transition_latency / 1000; |
439 | if (latency == 0) | |
440 | latency = 1; | |
1da177e4 | 441 | |
df8b59be | 442 | def_sampling_rate = latency * |
1da177e4 | 443 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
df8b59be DJ |
444 | |
445 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
446 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
447 | ||
1da177e4 | 448 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
1da177e4 LT |
449 | dbs_timer_init(); |
450 | } | |
32ee8c3e | 451 | |
3fc54d37 | 452 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
453 | break; |
454 | ||
455 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 456 | mutex_lock(&dbs_mutex); |
1da177e4 LT |
457 | this_dbs_info->enable = 0; |
458 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); | |
459 | dbs_enable--; | |
460 | /* | |
461 | * Stop the timerschedule work, when this governor | |
462 | * is used for first time | |
463 | */ | |
32ee8c3e | 464 | if (dbs_enable == 0) |
1da177e4 | 465 | dbs_timer_exit(); |
32ee8c3e | 466 | |
3fc54d37 | 467 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
468 | |
469 | break; | |
470 | ||
471 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 472 | mutex_lock(&dbs_mutex); |
1da177e4 LT |
473 | if (policy->max < this_dbs_info->cur_policy->cur) |
474 | __cpufreq_driver_target( | |
475 | this_dbs_info->cur_policy, | |
32ee8c3e | 476 | policy->max, CPUFREQ_RELATION_H); |
1da177e4 LT |
477 | else if (policy->min > this_dbs_info->cur_policy->cur) |
478 | __cpufreq_driver_target( | |
479 | this_dbs_info->cur_policy, | |
32ee8c3e | 480 | policy->min, CPUFREQ_RELATION_L); |
3fc54d37 | 481 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
482 | break; |
483 | } | |
484 | return 0; | |
485 | } | |
486 | ||
7f335d4e | 487 | static struct cpufreq_governor cpufreq_gov_dbs = { |
1da177e4 LT |
488 | .name = "ondemand", |
489 | .governor = cpufreq_governor_dbs, | |
490 | .owner = THIS_MODULE, | |
491 | }; | |
1da177e4 LT |
492 | |
493 | static int __init cpufreq_gov_dbs_init(void) | |
494 | { | |
495 | return cpufreq_register_governor(&cpufreq_gov_dbs); | |
496 | } | |
497 | ||
498 | static void __exit cpufreq_gov_dbs_exit(void) | |
499 | { | |
6810b548 AK |
500 | /* Make sure that the scheduled work is indeed not running. |
501 | Assumes the timer has been cancelled first. */ | |
502 | if (dbs_workq) { | |
503 | flush_workqueue(dbs_workq); | |
504 | destroy_workqueue(dbs_workq); | |
505 | } | |
1da177e4 LT |
506 | |
507 | cpufreq_unregister_governor(&cpufreq_gov_dbs); | |
508 | } | |
509 | ||
510 | ||
511 | MODULE_AUTHOR ("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>"); | |
512 | MODULE_DESCRIPTION ("'cpufreq_ondemand' - A dynamic cpufreq governor for " | |
513 | "Low Latency Frequency Transition capable processors"); | |
514 | MODULE_LICENSE ("GPL"); | |
515 | ||
516 | module_init(cpufreq_gov_dbs_init); | |
517 | module_exit(cpufreq_gov_dbs_exit); |