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b9170836 DJ |
1 | /* |
2 | * drivers/cpufreq/cpufreq_conservative.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 | * (C) 2004 Alexander Clouter <alex-kernel@digriz.org.uk> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | */ | |
13 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/ctype.h> | |
20 | #include <linux/cpufreq.h> | |
21 | #include <linux/sysctl.h> | |
22 | #include <linux/types.h> | |
23 | #include <linux/fs.h> | |
24 | #include <linux/sysfs.h> | |
25 | #include <linux/sched.h> | |
26 | #include <linux/kmod.h> | |
27 | #include <linux/workqueue.h> | |
28 | #include <linux/jiffies.h> | |
29 | #include <linux/kernel_stat.h> | |
30 | #include <linux/percpu.h> | |
3fc54d37 | 31 | #include <linux/mutex.h> |
b9170836 DJ |
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) | |
b9170836 | 38 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
b9170836 DJ |
39 | |
40 | /* | |
41 | * The polling frequency of this governor depends on the capability of | |
42 | * the processor. Default polling frequency is 1000 times the transition | |
43 | * latency of the processor. The governor will work on any processor with | |
44 | * transition latency <= 10mS, using appropriate sampling | |
45 | * rate. | |
46 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) | |
47 | * this governor will not work. | |
48 | * All times here are in uS. | |
49 | */ | |
50 | static unsigned int def_sampling_rate; | |
2c906b31 AC |
51 | #define MIN_SAMPLING_RATE_RATIO (2) |
52 | /* for correct statistics, we need at least 10 ticks between each measure */ | |
53 | #define MIN_STAT_SAMPLING_RATE (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) | |
54 | #define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) | |
b9170836 | 55 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
2c906b31 AC |
56 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) |
57 | #define DEF_SAMPLING_DOWN_FACTOR (1) | |
58 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
b9170836 DJ |
59 | #define TRANSITION_LATENCY_LIMIT (10 * 1000) |
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; | |
a159b827 AC |
68 | unsigned int down_skip; |
69 | unsigned int requested_freq; | |
b9170836 DJ |
70 | }; |
71 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); | |
72 | ||
73 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
74 | ||
3fc54d37 | 75 | static DEFINE_MUTEX (dbs_mutex); |
b9170836 DJ |
76 | static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); |
77 | ||
78 | struct dbs_tuners { | |
79 | unsigned int sampling_rate; | |
80 | unsigned int sampling_down_factor; | |
81 | unsigned int up_threshold; | |
82 | unsigned int down_threshold; | |
83 | unsigned int ignore_nice; | |
84 | unsigned int freq_step; | |
85 | }; | |
86 | ||
87 | static struct dbs_tuners dbs_tuners_ins = { | |
88 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, | |
89 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, | |
90 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
c326e27e MD |
91 | .ignore_nice = 0, |
92 | .freq_step = 5, | |
b9170836 DJ |
93 | }; |
94 | ||
dac1c1a5 DJ |
95 | static inline unsigned int get_cpu_idle_time(unsigned int cpu) |
96 | { | |
97 | return kstat_cpu(cpu).cpustat.idle + | |
98 | kstat_cpu(cpu).cpustat.iowait + | |
001893cd | 99 | ( dbs_tuners_ins.ignore_nice ? |
dac1c1a5 DJ |
100 | kstat_cpu(cpu).cpustat.nice : |
101 | 0); | |
102 | } | |
103 | ||
b9170836 DJ |
104 | /************************** sysfs interface ************************/ |
105 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
106 | { | |
107 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); | |
108 | } | |
109 | ||
110 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
111 | { | |
112 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); | |
113 | } | |
114 | ||
115 | #define define_one_ro(_name) \ | |
116 | static struct freq_attr _name = \ | |
117 | __ATTR(_name, 0444, show_##_name, NULL) | |
118 | ||
119 | define_one_ro(sampling_rate_max); | |
120 | define_one_ro(sampling_rate_min); | |
121 | ||
122 | /* cpufreq_conservative Governor Tunables */ | |
123 | #define show_one(file_name, object) \ | |
124 | static ssize_t show_##file_name \ | |
125 | (struct cpufreq_policy *unused, char *buf) \ | |
126 | { \ | |
127 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
128 | } | |
129 | show_one(sampling_rate, sampling_rate); | |
130 | show_one(sampling_down_factor, sampling_down_factor); | |
131 | show_one(up_threshold, up_threshold); | |
132 | show_one(down_threshold, down_threshold); | |
001893cd | 133 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
134 | show_one(freq_step, freq_step); |
135 | ||
136 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, | |
137 | const char *buf, size_t count) | |
138 | { | |
139 | unsigned int input; | |
140 | int ret; | |
141 | ret = sscanf (buf, "%u", &input); | |
2c906b31 | 142 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
143 | return -EINVAL; |
144 | ||
3fc54d37 | 145 | mutex_lock(&dbs_mutex); |
b9170836 | 146 | dbs_tuners_ins.sampling_down_factor = input; |
3fc54d37 | 147 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
148 | |
149 | return count; | |
150 | } | |
151 | ||
152 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, | |
153 | const char *buf, size_t count) | |
154 | { | |
155 | unsigned int input; | |
156 | int ret; | |
157 | ret = sscanf (buf, "%u", &input); | |
158 | ||
3fc54d37 | 159 | mutex_lock(&dbs_mutex); |
b9170836 | 160 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
3fc54d37 | 161 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
162 | return -EINVAL; |
163 | } | |
164 | ||
165 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 166 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
167 | |
168 | return count; | |
169 | } | |
170 | ||
171 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, | |
172 | const char *buf, size_t count) | |
173 | { | |
174 | unsigned int input; | |
175 | int ret; | |
176 | ret = sscanf (buf, "%u", &input); | |
177 | ||
3fc54d37 | 178 | mutex_lock(&dbs_mutex); |
b82fbe6c | 179 | if (ret != 1 || input > 100 || input <= dbs_tuners_ins.down_threshold) { |
3fc54d37 | 180 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
181 | return -EINVAL; |
182 | } | |
183 | ||
184 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 185 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
186 | |
187 | return count; | |
188 | } | |
189 | ||
190 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, | |
191 | const char *buf, size_t count) | |
192 | { | |
193 | unsigned int input; | |
194 | int ret; | |
195 | ret = sscanf (buf, "%u", &input); | |
196 | ||
3fc54d37 | 197 | mutex_lock(&dbs_mutex); |
b82fbe6c | 198 | if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) { |
3fc54d37 | 199 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
200 | return -EINVAL; |
201 | } | |
202 | ||
203 | dbs_tuners_ins.down_threshold = input; | |
3fc54d37 | 204 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
205 | |
206 | return count; | |
207 | } | |
208 | ||
001893cd | 209 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
b9170836 DJ |
210 | const char *buf, size_t count) |
211 | { | |
212 | unsigned int input; | |
213 | int ret; | |
214 | ||
215 | unsigned int j; | |
216 | ||
217 | ret = sscanf (buf, "%u", &input); | |
218 | if ( ret != 1 ) | |
219 | return -EINVAL; | |
220 | ||
221 | if ( input > 1 ) | |
222 | input = 1; | |
223 | ||
3fc54d37 | 224 | mutex_lock(&dbs_mutex); |
b9170836 | 225 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
3fc54d37 | 226 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
227 | return count; |
228 | } | |
229 | dbs_tuners_ins.ignore_nice = input; | |
230 | ||
231 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
dac1c1a5 | 232 | for_each_online_cpu(j) { |
b9170836 DJ |
233 | struct cpu_dbs_info_s *j_dbs_info; |
234 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
dac1c1a5 | 235 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
b9170836 DJ |
236 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
237 | } | |
3fc54d37 | 238 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
239 | |
240 | return count; | |
241 | } | |
242 | ||
243 | static ssize_t store_freq_step(struct cpufreq_policy *policy, | |
244 | const char *buf, size_t count) | |
245 | { | |
246 | unsigned int input; | |
247 | int ret; | |
248 | ||
249 | ret = sscanf (buf, "%u", &input); | |
250 | ||
251 | if ( ret != 1 ) | |
252 | return -EINVAL; | |
253 | ||
254 | if ( input > 100 ) | |
255 | input = 100; | |
256 | ||
257 | /* no need to test here if freq_step is zero as the user might actually | |
258 | * want this, they would be crazy though :) */ | |
3fc54d37 | 259 | mutex_lock(&dbs_mutex); |
b9170836 | 260 | dbs_tuners_ins.freq_step = input; |
3fc54d37 | 261 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
262 | |
263 | return count; | |
264 | } | |
265 | ||
266 | #define define_one_rw(_name) \ | |
267 | static struct freq_attr _name = \ | |
268 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
269 | ||
270 | define_one_rw(sampling_rate); | |
271 | define_one_rw(sampling_down_factor); | |
272 | define_one_rw(up_threshold); | |
273 | define_one_rw(down_threshold); | |
001893cd | 274 | define_one_rw(ignore_nice_load); |
b9170836 DJ |
275 | define_one_rw(freq_step); |
276 | ||
277 | static struct attribute * dbs_attributes[] = { | |
278 | &sampling_rate_max.attr, | |
279 | &sampling_rate_min.attr, | |
280 | &sampling_rate.attr, | |
281 | &sampling_down_factor.attr, | |
282 | &up_threshold.attr, | |
283 | &down_threshold.attr, | |
001893cd | 284 | &ignore_nice_load.attr, |
b9170836 DJ |
285 | &freq_step.attr, |
286 | NULL | |
287 | }; | |
288 | ||
289 | static struct attribute_group dbs_attr_group = { | |
290 | .attrs = dbs_attributes, | |
291 | .name = "conservative", | |
292 | }; | |
293 | ||
294 | /************************** sysfs end ************************/ | |
295 | ||
296 | static void dbs_check_cpu(int cpu) | |
297 | { | |
298 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; | |
08a28e2e | 299 | unsigned int tmp_idle_ticks, total_idle_ticks; |
b9170836 DJ |
300 | unsigned int freq_step; |
301 | unsigned int freq_down_sampling_rate; | |
08a28e2e | 302 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
b9170836 | 303 | struct cpufreq_policy *policy; |
b9170836 | 304 | |
b9170836 DJ |
305 | if (!this_dbs_info->enable) |
306 | return; | |
307 | ||
08a28e2e AC |
308 | policy = this_dbs_info->cur_policy; |
309 | ||
b9170836 DJ |
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 | |
321 | * 5% (default) of max_frequency | |
322 | */ | |
323 | ||
324 | /* Check for frequency increase */ | |
9c7d269b | 325 | idle_ticks = UINT_MAX; |
b9170836 | 326 | |
08a28e2e AC |
327 | /* Check for frequency increase */ |
328 | total_idle_ticks = get_cpu_idle_time(cpu); | |
329 | tmp_idle_ticks = total_idle_ticks - | |
330 | this_dbs_info->prev_cpu_idle_up; | |
331 | this_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
332 | ||
333 | if (tmp_idle_ticks < idle_ticks) | |
334 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
335 | |
336 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
337 | idle_ticks *= 100; | |
338 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
2c906b31 | 339 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
b9170836 DJ |
340 | |
341 | if (idle_ticks < up_idle_ticks) { | |
a159b827 | 342 | this_dbs_info->down_skip = 0; |
08a28e2e AC |
343 | this_dbs_info->prev_cpu_idle_down = |
344 | this_dbs_info->prev_cpu_idle_up; | |
790d76fa | 345 | |
b9170836 | 346 | /* if we are already at full speed then break out early */ |
a159b827 | 347 | if (this_dbs_info->requested_freq == policy->max) |
b9170836 DJ |
348 | return; |
349 | ||
350 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
351 | ||
352 | /* max freq cannot be less than 100. But who knows.... */ | |
353 | if (unlikely(freq_step == 0)) | |
354 | freq_step = 5; | |
355 | ||
a159b827 AC |
356 | this_dbs_info->requested_freq += freq_step; |
357 | if (this_dbs_info->requested_freq > policy->max) | |
358 | this_dbs_info->requested_freq = policy->max; | |
b9170836 | 359 | |
a159b827 | 360 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
b9170836 | 361 | CPUFREQ_RELATION_H); |
b9170836 DJ |
362 | return; |
363 | } | |
364 | ||
365 | /* Check for frequency decrease */ | |
a159b827 AC |
366 | this_dbs_info->down_skip++; |
367 | if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor) | |
b9170836 DJ |
368 | return; |
369 | ||
08a28e2e AC |
370 | /* Check for frequency decrease */ |
371 | total_idle_ticks = this_dbs_info->prev_cpu_idle_up; | |
372 | tmp_idle_ticks = total_idle_ticks - | |
373 | this_dbs_info->prev_cpu_idle_down; | |
374 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
b9170836 | 375 | |
08a28e2e AC |
376 | if (tmp_idle_ticks < idle_ticks) |
377 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
378 | |
379 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
380 | idle_ticks *= 100; | |
a159b827 | 381 | this_dbs_info->down_skip = 0; |
b9170836 DJ |
382 | |
383 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * | |
384 | dbs_tuners_ins.sampling_down_factor; | |
385 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * | |
2c906b31 | 386 | usecs_to_jiffies(freq_down_sampling_rate); |
b9170836 | 387 | |
9c7d269b | 388 | if (idle_ticks > down_idle_ticks) { |
2c906b31 AC |
389 | /* |
390 | * if we are already at the lowest speed then break out early | |
b9170836 | 391 | * or if we 'cannot' reduce the speed as the user might want |
2c906b31 AC |
392 | * freq_step to be zero |
393 | */ | |
a159b827 | 394 | if (this_dbs_info->requested_freq == policy->min |
b9170836 DJ |
395 | || dbs_tuners_ins.freq_step == 0) |
396 | return; | |
397 | ||
398 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
399 | ||
400 | /* max freq cannot be less than 100. But who knows.... */ | |
401 | if (unlikely(freq_step == 0)) | |
402 | freq_step = 5; | |
403 | ||
a159b827 AC |
404 | this_dbs_info->requested_freq -= freq_step; |
405 | if (this_dbs_info->requested_freq < policy->min) | |
406 | this_dbs_info->requested_freq = policy->min; | |
b9170836 | 407 | |
a159b827 | 408 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
2c906b31 | 409 | CPUFREQ_RELATION_H); |
b9170836 DJ |
410 | return; |
411 | } | |
412 | } | |
413 | ||
414 | static void do_dbs_timer(void *data) | |
415 | { | |
416 | int i; | |
3fc54d37 | 417 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
418 | for_each_online_cpu(i) |
419 | dbs_check_cpu(i); | |
420 | schedule_delayed_work(&dbs_work, | |
421 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
3fc54d37 | 422 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
423 | } |
424 | ||
425 | static inline void dbs_timer_init(void) | |
426 | { | |
427 | INIT_WORK(&dbs_work, do_dbs_timer, NULL); | |
428 | schedule_delayed_work(&dbs_work, | |
429 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
430 | return; | |
431 | } | |
432 | ||
433 | static inline void dbs_timer_exit(void) | |
434 | { | |
435 | cancel_delayed_work(&dbs_work); | |
436 | return; | |
437 | } | |
438 | ||
439 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
440 | unsigned int event) | |
441 | { | |
442 | unsigned int cpu = policy->cpu; | |
443 | struct cpu_dbs_info_s *this_dbs_info; | |
444 | unsigned int j; | |
445 | ||
446 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
447 | ||
448 | switch (event) { | |
449 | case CPUFREQ_GOV_START: | |
450 | if ((!cpu_online(cpu)) || | |
451 | (!policy->cur)) | |
452 | return -EINVAL; | |
453 | ||
454 | if (policy->cpuinfo.transition_latency > | |
455 | (TRANSITION_LATENCY_LIMIT * 1000)) | |
456 | return -EINVAL; | |
457 | if (this_dbs_info->enable) /* Already enabled */ | |
458 | break; | |
459 | ||
3fc54d37 | 460 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
461 | for_each_cpu_mask(j, policy->cpus) { |
462 | struct cpu_dbs_info_s *j_dbs_info; | |
463 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
464 | j_dbs_info->cur_policy = policy; | |
465 | ||
08a28e2e | 466 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(cpu); |
b9170836 DJ |
467 | j_dbs_info->prev_cpu_idle_down |
468 | = j_dbs_info->prev_cpu_idle_up; | |
469 | } | |
470 | this_dbs_info->enable = 1; | |
a159b827 AC |
471 | this_dbs_info->down_skip = 0; |
472 | this_dbs_info->requested_freq = policy->cur; | |
b9170836 DJ |
473 | sysfs_create_group(&policy->kobj, &dbs_attr_group); |
474 | dbs_enable++; | |
475 | /* | |
476 | * Start the timerschedule work, when this governor | |
477 | * is used for first time | |
478 | */ | |
479 | if (dbs_enable == 1) { | |
480 | unsigned int latency; | |
481 | /* policy latency is in nS. Convert it to uS first */ | |
2c906b31 AC |
482 | latency = policy->cpuinfo.transition_latency / 1000; |
483 | if (latency == 0) | |
484 | latency = 1; | |
b9170836 | 485 | |
e8a02572 | 486 | def_sampling_rate = 10 * latency * |
b9170836 | 487 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
2c906b31 AC |
488 | |
489 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
490 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
491 | ||
b9170836 | 492 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
b9170836 DJ |
493 | |
494 | dbs_timer_init(); | |
495 | } | |
496 | ||
3fc54d37 | 497 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
498 | break; |
499 | ||
500 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 501 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
502 | this_dbs_info->enable = 0; |
503 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); | |
504 | dbs_enable--; | |
505 | /* | |
506 | * Stop the timerschedule work, when this governor | |
507 | * is used for first time | |
508 | */ | |
509 | if (dbs_enable == 0) | |
510 | dbs_timer_exit(); | |
511 | ||
3fc54d37 | 512 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
513 | |
514 | break; | |
515 | ||
516 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 517 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
518 | if (policy->max < this_dbs_info->cur_policy->cur) |
519 | __cpufreq_driver_target( | |
520 | this_dbs_info->cur_policy, | |
521 | policy->max, CPUFREQ_RELATION_H); | |
522 | else if (policy->min > this_dbs_info->cur_policy->cur) | |
523 | __cpufreq_driver_target( | |
524 | this_dbs_info->cur_policy, | |
525 | policy->min, CPUFREQ_RELATION_L); | |
3fc54d37 | 526 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
527 | break; |
528 | } | |
529 | return 0; | |
530 | } | |
531 | ||
532 | static struct cpufreq_governor cpufreq_gov_dbs = { | |
533 | .name = "conservative", | |
534 | .governor = cpufreq_governor_dbs, | |
535 | .owner = THIS_MODULE, | |
536 | }; | |
537 | ||
538 | static int __init cpufreq_gov_dbs_init(void) | |
539 | { | |
540 | return cpufreq_register_governor(&cpufreq_gov_dbs); | |
541 | } | |
542 | ||
543 | static void __exit cpufreq_gov_dbs_exit(void) | |
544 | { | |
545 | /* Make sure that the scheduled work is indeed not running */ | |
546 | flush_scheduled_work(); | |
547 | ||
548 | cpufreq_unregister_governor(&cpufreq_gov_dbs); | |
549 | } | |
550 | ||
551 | ||
552 | MODULE_AUTHOR ("Alexander Clouter <alex-kernel@digriz.org.uk>"); | |
553 | MODULE_DESCRIPTION ("'cpufreq_conservative' - A dynamic cpufreq governor for " | |
554 | "Low Latency Frequency Transition capable processors " | |
555 | "optimised for use in a battery environment"); | |
556 | MODULE_LICENSE ("GPL"); | |
557 | ||
558 | module_init(cpufreq_gov_dbs_init); | |
559 | module_exit(cpufreq_gov_dbs_exit); |