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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> | |
30 | ||
31 | /* | |
32 | * dbs is used in this file as a shortform for demandbased switching | |
33 | * It helps to keep variable names smaller, simpler | |
34 | */ | |
35 | ||
36 | #define DEF_FREQUENCY_UP_THRESHOLD (80) | |
37 | #define MIN_FREQUENCY_UP_THRESHOLD (0) | |
38 | #define MAX_FREQUENCY_UP_THRESHOLD (100) | |
39 | ||
40 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) | |
41 | #define MIN_FREQUENCY_DOWN_THRESHOLD (0) | |
42 | #define MAX_FREQUENCY_DOWN_THRESHOLD (100) | |
43 | ||
44 | /* | |
45 | * The polling frequency of this governor depends on the capability of | |
46 | * the processor. Default polling frequency is 1000 times the transition | |
47 | * latency of the processor. The governor will work on any processor with | |
48 | * transition latency <= 10mS, using appropriate sampling | |
49 | * rate. | |
50 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) | |
51 | * this governor will not work. | |
52 | * All times here are in uS. | |
53 | */ | |
54 | static unsigned int def_sampling_rate; | |
55 | #define MIN_SAMPLING_RATE (def_sampling_rate / 2) | |
56 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) | |
57 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) | |
58 | #define DEF_SAMPLING_DOWN_FACTOR (10) | |
59 | #define TRANSITION_LATENCY_LIMIT (10 * 1000) | |
1da177e4 LT |
60 | |
61 | static void do_dbs_timer(void *data); | |
62 | ||
63 | struct cpu_dbs_info_s { | |
64 | struct cpufreq_policy *cur_policy; | |
65 | unsigned int prev_cpu_idle_up; | |
66 | unsigned int prev_cpu_idle_down; | |
67 | unsigned int enable; | |
68 | }; | |
69 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); | |
70 | ||
71 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
72 | ||
73 | static DECLARE_MUTEX (dbs_sem); | |
74 | static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); | |
75 | ||
76 | struct dbs_tuners { | |
77 | unsigned int sampling_rate; | |
78 | unsigned int sampling_down_factor; | |
79 | unsigned int up_threshold; | |
80 | unsigned int down_threshold; | |
3d5ee9e5 | 81 | unsigned int ignore_nice; |
1206aaac | 82 | unsigned int freq_step; |
1da177e4 LT |
83 | }; |
84 | ||
85 | static struct dbs_tuners dbs_tuners_ins = { | |
86 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, | |
87 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, | |
88 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
89 | }; | |
90 | ||
91 | /************************** sysfs interface ************************/ | |
92 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
93 | { | |
94 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); | |
95 | } | |
96 | ||
97 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
98 | { | |
99 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); | |
100 | } | |
101 | ||
102 | #define define_one_ro(_name) \ | |
103 | static struct freq_attr _name = \ | |
104 | __ATTR(_name, 0444, show_##_name, NULL) | |
105 | ||
106 | define_one_ro(sampling_rate_max); | |
107 | define_one_ro(sampling_rate_min); | |
108 | ||
109 | /* cpufreq_ondemand Governor Tunables */ | |
110 | #define show_one(file_name, object) \ | |
111 | static ssize_t show_##file_name \ | |
112 | (struct cpufreq_policy *unused, char *buf) \ | |
113 | { \ | |
114 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
115 | } | |
116 | show_one(sampling_rate, sampling_rate); | |
117 | show_one(sampling_down_factor, sampling_down_factor); | |
118 | show_one(up_threshold, up_threshold); | |
119 | show_one(down_threshold, down_threshold); | |
3d5ee9e5 | 120 | show_one(ignore_nice, ignore_nice); |
1206aaac | 121 | show_one(freq_step, freq_step); |
1da177e4 LT |
122 | |
123 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, | |
124 | const char *buf, size_t count) | |
125 | { | |
126 | unsigned int input; | |
127 | int ret; | |
128 | ret = sscanf (buf, "%u", &input); | |
129 | if (ret != 1 ) | |
130 | return -EINVAL; | |
131 | ||
132 | down(&dbs_sem); | |
133 | dbs_tuners_ins.sampling_down_factor = input; | |
134 | up(&dbs_sem); | |
135 | ||
136 | return count; | |
137 | } | |
138 | ||
139 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, | |
140 | const char *buf, size_t count) | |
141 | { | |
142 | unsigned int input; | |
143 | int ret; | |
144 | ret = sscanf (buf, "%u", &input); | |
145 | ||
146 | down(&dbs_sem); | |
147 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { | |
148 | up(&dbs_sem); | |
149 | return -EINVAL; | |
150 | } | |
151 | ||
152 | dbs_tuners_ins.sampling_rate = input; | |
153 | up(&dbs_sem); | |
154 | ||
155 | return count; | |
156 | } | |
157 | ||
158 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, | |
159 | const char *buf, size_t count) | |
160 | { | |
161 | unsigned int input; | |
162 | int ret; | |
163 | ret = sscanf (buf, "%u", &input); | |
164 | ||
165 | down(&dbs_sem); | |
166 | if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || | |
167 | input < MIN_FREQUENCY_UP_THRESHOLD || | |
168 | input <= dbs_tuners_ins.down_threshold) { | |
169 | up(&dbs_sem); | |
170 | return -EINVAL; | |
171 | } | |
172 | ||
173 | dbs_tuners_ins.up_threshold = input; | |
174 | up(&dbs_sem); | |
175 | ||
176 | return count; | |
177 | } | |
178 | ||
179 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, | |
180 | const char *buf, size_t count) | |
181 | { | |
182 | unsigned int input; | |
183 | int ret; | |
184 | ret = sscanf (buf, "%u", &input); | |
185 | ||
186 | down(&dbs_sem); | |
187 | if (ret != 1 || input > MAX_FREQUENCY_DOWN_THRESHOLD || | |
188 | input < MIN_FREQUENCY_DOWN_THRESHOLD || | |
189 | input >= dbs_tuners_ins.up_threshold) { | |
190 | up(&dbs_sem); | |
191 | return -EINVAL; | |
192 | } | |
193 | ||
194 | dbs_tuners_ins.down_threshold = input; | |
195 | up(&dbs_sem); | |
196 | ||
197 | return count; | |
198 | } | |
199 | ||
3d5ee9e5 DJ |
200 | static ssize_t store_ignore_nice(struct cpufreq_policy *policy, |
201 | const char *buf, size_t count) | |
202 | { | |
203 | unsigned int input; | |
204 | int ret; | |
205 | ||
206 | unsigned int j; | |
207 | ||
208 | ret = sscanf (buf, "%u", &input); | |
209 | if ( ret != 1 ) | |
210 | return -EINVAL; | |
211 | ||
212 | if ( input > 1 ) | |
213 | input = 1; | |
214 | ||
215 | down(&dbs_sem); | |
216 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ | |
217 | up(&dbs_sem); | |
218 | return count; | |
219 | } | |
220 | dbs_tuners_ins.ignore_nice = input; | |
221 | ||
222 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
223 | for_each_cpu_mask(j, policy->cpus) { | |
224 | struct cpu_dbs_info_s *j_dbs_info; | |
225 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
226 | j_dbs_info->cur_policy = policy; | |
227 | ||
228 | j_dbs_info->prev_cpu_idle_up = | |
229 | kstat_cpu(j).cpustat.idle + | |
230 | kstat_cpu(j).cpustat.iowait + | |
231 | ( !dbs_tuners_ins.ignore_nice | |
232 | ? kstat_cpu(j).cpustat.nice : 0 ); | |
233 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; | |
234 | } | |
235 | up(&dbs_sem); | |
236 | ||
237 | return count; | |
238 | } | |
239 | ||
1206aaac DJ |
240 | static ssize_t store_freq_step(struct cpufreq_policy *policy, |
241 | const char *buf, size_t count) | |
242 | { | |
243 | unsigned int input; | |
244 | int ret; | |
245 | ||
246 | ret = sscanf (buf, "%u", &input); | |
247 | ||
248 | if ( ret != 1 ) | |
249 | return -EINVAL; | |
250 | ||
251 | if ( input > 100 ) | |
252 | input = 100; | |
253 | ||
254 | /* no need to test here if freq_step is zero as the user might actually | |
255 | * want this, they would be crazy though :) */ | |
256 | down(&dbs_sem); | |
257 | dbs_tuners_ins.freq_step = input; | |
258 | up(&dbs_sem); | |
259 | ||
260 | return count; | |
261 | } | |
262 | ||
1da177e4 LT |
263 | #define define_one_rw(_name) \ |
264 | static struct freq_attr _name = \ | |
265 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
266 | ||
267 | define_one_rw(sampling_rate); | |
268 | define_one_rw(sampling_down_factor); | |
269 | define_one_rw(up_threshold); | |
270 | define_one_rw(down_threshold); | |
3d5ee9e5 | 271 | define_one_rw(ignore_nice); |
1206aaac | 272 | define_one_rw(freq_step); |
1da177e4 LT |
273 | |
274 | static struct attribute * dbs_attributes[] = { | |
275 | &sampling_rate_max.attr, | |
276 | &sampling_rate_min.attr, | |
277 | &sampling_rate.attr, | |
278 | &sampling_down_factor.attr, | |
279 | &up_threshold.attr, | |
280 | &down_threshold.attr, | |
3d5ee9e5 | 281 | &ignore_nice.attr, |
1206aaac | 282 | &freq_step.attr, |
1da177e4 LT |
283 | NULL |
284 | }; | |
285 | ||
286 | static struct attribute_group dbs_attr_group = { | |
287 | .attrs = dbs_attributes, | |
288 | .name = "ondemand", | |
289 | }; | |
290 | ||
291 | /************************** sysfs end ************************/ | |
292 | ||
293 | static void dbs_check_cpu(int cpu) | |
294 | { | |
295 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; | |
296 | unsigned int total_idle_ticks; | |
297 | unsigned int freq_down_step; | |
298 | unsigned int freq_down_sampling_rate; | |
299 | static int down_skip[NR_CPUS]; | |
300 | struct cpu_dbs_info_s *this_dbs_info; | |
301 | ||
302 | struct cpufreq_policy *policy; | |
303 | unsigned int j; | |
304 | ||
305 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
306 | if (!this_dbs_info->enable) | |
307 | return; | |
308 | ||
309 | policy = this_dbs_info->cur_policy; | |
310 | /* | |
311 | * The default safe range is 20% to 80% | |
312 | * Every sampling_rate, we check | |
313 | * - If current idle time is less than 20%, then we try to | |
314 | * increase frequency | |
315 | * Every sampling_rate*sampling_down_factor, we check | |
316 | * - If current idle time is more than 80%, then we try to | |
317 | * decrease frequency | |
318 | * | |
319 | * Any frequency increase takes it to the maximum frequency. | |
320 | * Frequency reduction happens at minimum steps of | |
1206aaac | 321 | * 5% (default) of max_frequency |
1da177e4 LT |
322 | */ |
323 | ||
324 | /* Check for frequency increase */ | |
325 | total_idle_ticks = kstat_cpu(cpu).cpustat.idle + | |
326 | kstat_cpu(cpu).cpustat.iowait; | |
3d5ee9e5 DJ |
327 | /* consider 'nice' tasks as 'idle' time too if required */ |
328 | if (dbs_tuners_ins.ignore_nice == 0) | |
329 | total_idle_ticks += kstat_cpu(cpu).cpustat.nice; | |
1da177e4 LT |
330 | idle_ticks = total_idle_ticks - |
331 | this_dbs_info->prev_cpu_idle_up; | |
332 | this_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
333 | ||
334 | ||
335 | for_each_cpu_mask(j, policy->cpus) { | |
336 | unsigned int tmp_idle_ticks; | |
337 | struct cpu_dbs_info_s *j_dbs_info; | |
338 | ||
339 | if (j == cpu) | |
340 | continue; | |
341 | ||
342 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
343 | /* Check for frequency increase */ | |
344 | total_idle_ticks = kstat_cpu(j).cpustat.idle + | |
345 | kstat_cpu(j).cpustat.iowait; | |
3d5ee9e5 DJ |
346 | /* consider 'nice' too? */ |
347 | if (dbs_tuners_ins.ignore_nice == 0) | |
348 | total_idle_ticks += kstat_cpu(j).cpustat.nice; | |
1da177e4 LT |
349 | tmp_idle_ticks = total_idle_ticks - |
350 | j_dbs_info->prev_cpu_idle_up; | |
351 | j_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
352 | ||
353 | if (tmp_idle_ticks < idle_ticks) | |
354 | idle_ticks = tmp_idle_ticks; | |
355 | } | |
356 | ||
357 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
358 | idle_ticks *= 100; | |
359 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
6fe71165 | 360 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
1da177e4 LT |
361 | |
362 | if (idle_ticks < up_idle_ticks) { | |
c11420a6 DJ |
363 | /* if we are already at full speed then break out early */ |
364 | if (policy->cur == policy->max) | |
365 | return; | |
366 | ||
1da177e4 LT |
367 | __cpufreq_driver_target(policy, policy->max, |
368 | CPUFREQ_RELATION_H); | |
369 | down_skip[cpu] = 0; | |
370 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
371 | return; | |
372 | } | |
373 | ||
374 | /* Check for frequency decrease */ | |
375 | down_skip[cpu]++; | |
376 | if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor) | |
377 | return; | |
378 | ||
379 | total_idle_ticks = kstat_cpu(cpu).cpustat.idle + | |
380 | kstat_cpu(cpu).cpustat.iowait; | |
3d5ee9e5 DJ |
381 | /* consider 'nice' too? */ |
382 | if (dbs_tuners_ins.ignore_nice == 0) | |
383 | total_idle_ticks += kstat_cpu(cpu).cpustat.nice; | |
1da177e4 LT |
384 | idle_ticks = total_idle_ticks - |
385 | this_dbs_info->prev_cpu_idle_down; | |
386 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
387 | ||
388 | for_each_cpu_mask(j, policy->cpus) { | |
389 | unsigned int tmp_idle_ticks; | |
390 | struct cpu_dbs_info_s *j_dbs_info; | |
391 | ||
392 | if (j == cpu) | |
393 | continue; | |
394 | ||
395 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
396 | /* Check for frequency increase */ | |
397 | total_idle_ticks = kstat_cpu(j).cpustat.idle + | |
398 | kstat_cpu(j).cpustat.iowait; | |
3d5ee9e5 DJ |
399 | /* consider 'nice' too? */ |
400 | if (dbs_tuners_ins.ignore_nice == 0) | |
401 | total_idle_ticks += kstat_cpu(j).cpustat.nice; | |
1da177e4 LT |
402 | tmp_idle_ticks = total_idle_ticks - |
403 | j_dbs_info->prev_cpu_idle_down; | |
404 | j_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
405 | ||
406 | if (tmp_idle_ticks < idle_ticks) | |
407 | idle_ticks = tmp_idle_ticks; | |
408 | } | |
409 | ||
410 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
411 | idle_ticks *= 100; | |
412 | down_skip[cpu] = 0; | |
413 | ||
414 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * | |
415 | dbs_tuners_ins.sampling_down_factor; | |
416 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * | |
6fe71165 | 417 | usecs_to_jiffies(freq_down_sampling_rate); |
1da177e4 LT |
418 | |
419 | if (idle_ticks > down_idle_ticks ) { | |
1206aaac DJ |
420 | /* if we are already at the lowest speed then break out early |
421 | * or if we 'cannot' reduce the speed as the user might want | |
422 | * freq_step to be zero */ | |
423 | if (policy->cur == policy->min || dbs_tuners_ins.freq_step == 0) | |
c11420a6 | 424 | return; |
1206aaac DJ |
425 | |
426 | freq_down_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
1da177e4 LT |
427 | |
428 | /* max freq cannot be less than 100. But who knows.... */ | |
429 | if (unlikely(freq_down_step == 0)) | |
430 | freq_down_step = 5; | |
431 | ||
432 | __cpufreq_driver_target(policy, | |
1206aaac | 433 | policy->cur - freq_down_step, |
1da177e4 LT |
434 | CPUFREQ_RELATION_H); |
435 | return; | |
436 | } | |
437 | } | |
438 | ||
439 | static void do_dbs_timer(void *data) | |
440 | { | |
441 | int i; | |
442 | down(&dbs_sem); | |
6fe71165 DJ |
443 | for_each_online_cpu(i) |
444 | dbs_check_cpu(i); | |
1da177e4 | 445 | schedule_delayed_work(&dbs_work, |
6fe71165 | 446 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
1da177e4 LT |
447 | up(&dbs_sem); |
448 | } | |
449 | ||
450 | static inline void dbs_timer_init(void) | |
451 | { | |
452 | INIT_WORK(&dbs_work, do_dbs_timer, NULL); | |
453 | schedule_delayed_work(&dbs_work, | |
6fe71165 | 454 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
1da177e4 LT |
455 | return; |
456 | } | |
457 | ||
458 | static inline void dbs_timer_exit(void) | |
459 | { | |
460 | cancel_delayed_work(&dbs_work); | |
461 | return; | |
462 | } | |
463 | ||
464 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
465 | unsigned int event) | |
466 | { | |
467 | unsigned int cpu = policy->cpu; | |
468 | struct cpu_dbs_info_s *this_dbs_info; | |
469 | unsigned int j; | |
470 | ||
471 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
472 | ||
473 | switch (event) { | |
474 | case CPUFREQ_GOV_START: | |
475 | if ((!cpu_online(cpu)) || | |
476 | (!policy->cur)) | |
477 | return -EINVAL; | |
478 | ||
479 | if (policy->cpuinfo.transition_latency > | |
480 | (TRANSITION_LATENCY_LIMIT * 1000)) | |
481 | return -EINVAL; | |
482 | if (this_dbs_info->enable) /* Already enabled */ | |
483 | break; | |
484 | ||
485 | down(&dbs_sem); | |
486 | for_each_cpu_mask(j, policy->cpus) { | |
487 | struct cpu_dbs_info_s *j_dbs_info; | |
488 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
489 | j_dbs_info->cur_policy = policy; | |
490 | ||
491 | j_dbs_info->prev_cpu_idle_up = | |
492 | kstat_cpu(j).cpustat.idle + | |
3d5ee9e5 DJ |
493 | kstat_cpu(j).cpustat.iowait + |
494 | ( !dbs_tuners_ins.ignore_nice | |
495 | ? kstat_cpu(j).cpustat.nice : 0 ); | |
496 | j_dbs_info->prev_cpu_idle_down | |
497 | = j_dbs_info->prev_cpu_idle_up; | |
1da177e4 LT |
498 | } |
499 | this_dbs_info->enable = 1; | |
500 | sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
501 | dbs_enable++; | |
502 | /* | |
503 | * Start the timerschedule work, when this governor | |
504 | * is used for first time | |
505 | */ | |
506 | if (dbs_enable == 1) { | |
507 | unsigned int latency; | |
508 | /* policy latency is in nS. Convert it to uS first */ | |
509 | ||
510 | latency = policy->cpuinfo.transition_latency; | |
511 | if (latency < 1000) | |
512 | latency = 1000; | |
513 | ||
514 | def_sampling_rate = (latency / 1000) * | |
515 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; | |
516 | dbs_tuners_ins.sampling_rate = def_sampling_rate; | |
3d5ee9e5 | 517 | dbs_tuners_ins.ignore_nice = 0; |
1206aaac | 518 | dbs_tuners_ins.freq_step = 5; |
1da177e4 LT |
519 | |
520 | dbs_timer_init(); | |
521 | } | |
522 | ||
523 | up(&dbs_sem); | |
524 | break; | |
525 | ||
526 | case CPUFREQ_GOV_STOP: | |
527 | down(&dbs_sem); | |
528 | this_dbs_info->enable = 0; | |
529 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); | |
530 | dbs_enable--; | |
531 | /* | |
532 | * Stop the timerschedule work, when this governor | |
533 | * is used for first time | |
534 | */ | |
535 | if (dbs_enable == 0) | |
536 | dbs_timer_exit(); | |
537 | ||
538 | up(&dbs_sem); | |
539 | ||
540 | break; | |
541 | ||
542 | case CPUFREQ_GOV_LIMITS: | |
543 | down(&dbs_sem); | |
544 | if (policy->max < this_dbs_info->cur_policy->cur) | |
545 | __cpufreq_driver_target( | |
546 | this_dbs_info->cur_policy, | |
547 | policy->max, CPUFREQ_RELATION_H); | |
548 | else if (policy->min > this_dbs_info->cur_policy->cur) | |
549 | __cpufreq_driver_target( | |
550 | this_dbs_info->cur_policy, | |
551 | policy->min, CPUFREQ_RELATION_L); | |
552 | up(&dbs_sem); | |
553 | break; | |
554 | } | |
555 | return 0; | |
556 | } | |
557 | ||
7f335d4e | 558 | static struct cpufreq_governor cpufreq_gov_dbs = { |
1da177e4 LT |
559 | .name = "ondemand", |
560 | .governor = cpufreq_governor_dbs, | |
561 | .owner = THIS_MODULE, | |
562 | }; | |
1da177e4 LT |
563 | |
564 | static int __init cpufreq_gov_dbs_init(void) | |
565 | { | |
566 | return cpufreq_register_governor(&cpufreq_gov_dbs); | |
567 | } | |
568 | ||
569 | static void __exit cpufreq_gov_dbs_exit(void) | |
570 | { | |
571 | /* Make sure that the scheduled work is indeed not running */ | |
572 | flush_scheduled_work(); | |
573 | ||
574 | cpufreq_unregister_governor(&cpufreq_gov_dbs); | |
575 | } | |
576 | ||
577 | ||
578 | MODULE_AUTHOR ("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>"); | |
579 | MODULE_DESCRIPTION ("'cpufreq_ondemand' - A dynamic cpufreq governor for " | |
580 | "Low Latency Frequency Transition capable processors"); | |
581 | MODULE_LICENSE ("GPL"); | |
582 | ||
583 | module_init(cpufreq_gov_dbs_init); | |
584 | module_exit(cpufreq_gov_dbs_exit); |