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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 | ||
4ec223d0 VP |
75 | /* |
76 | * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug | |
77 | * lock and dbs_mutex. cpu_hotplug lock should always be held before | |
78 | * dbs_mutex. If any function that can potentially take cpu_hotplug lock | |
79 | * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then | |
80 | * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock | |
81 | * is recursive for the same process. -Venki | |
82 | */ | |
3fc54d37 | 83 | static DEFINE_MUTEX (dbs_mutex); |
b9170836 DJ |
84 | static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); |
85 | ||
86 | struct dbs_tuners { | |
87 | unsigned int sampling_rate; | |
88 | unsigned int sampling_down_factor; | |
89 | unsigned int up_threshold; | |
90 | unsigned int down_threshold; | |
91 | unsigned int ignore_nice; | |
92 | unsigned int freq_step; | |
93 | }; | |
94 | ||
95 | static struct dbs_tuners dbs_tuners_ins = { | |
96 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, | |
97 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, | |
98 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
c326e27e MD |
99 | .ignore_nice = 0, |
100 | .freq_step = 5, | |
b9170836 DJ |
101 | }; |
102 | ||
dac1c1a5 DJ |
103 | static inline unsigned int get_cpu_idle_time(unsigned int cpu) |
104 | { | |
105 | return kstat_cpu(cpu).cpustat.idle + | |
106 | kstat_cpu(cpu).cpustat.iowait + | |
001893cd | 107 | ( dbs_tuners_ins.ignore_nice ? |
dac1c1a5 DJ |
108 | kstat_cpu(cpu).cpustat.nice : |
109 | 0); | |
110 | } | |
111 | ||
b9170836 DJ |
112 | /************************** sysfs interface ************************/ |
113 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
114 | { | |
115 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); | |
116 | } | |
117 | ||
118 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
119 | { | |
120 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); | |
121 | } | |
122 | ||
123 | #define define_one_ro(_name) \ | |
124 | static struct freq_attr _name = \ | |
125 | __ATTR(_name, 0444, show_##_name, NULL) | |
126 | ||
127 | define_one_ro(sampling_rate_max); | |
128 | define_one_ro(sampling_rate_min); | |
129 | ||
130 | /* cpufreq_conservative Governor Tunables */ | |
131 | #define show_one(file_name, object) \ | |
132 | static ssize_t show_##file_name \ | |
133 | (struct cpufreq_policy *unused, char *buf) \ | |
134 | { \ | |
135 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
136 | } | |
137 | show_one(sampling_rate, sampling_rate); | |
138 | show_one(sampling_down_factor, sampling_down_factor); | |
139 | show_one(up_threshold, up_threshold); | |
140 | show_one(down_threshold, down_threshold); | |
001893cd | 141 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
142 | show_one(freq_step, freq_step); |
143 | ||
144 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, | |
145 | const char *buf, size_t count) | |
146 | { | |
147 | unsigned int input; | |
148 | int ret; | |
149 | ret = sscanf (buf, "%u", &input); | |
2c906b31 | 150 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
151 | return -EINVAL; |
152 | ||
3fc54d37 | 153 | mutex_lock(&dbs_mutex); |
b9170836 | 154 | dbs_tuners_ins.sampling_down_factor = input; |
3fc54d37 | 155 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
156 | |
157 | return count; | |
158 | } | |
159 | ||
160 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, | |
161 | const char *buf, size_t count) | |
162 | { | |
163 | unsigned int input; | |
164 | int ret; | |
165 | ret = sscanf (buf, "%u", &input); | |
166 | ||
3fc54d37 | 167 | mutex_lock(&dbs_mutex); |
b9170836 | 168 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
3fc54d37 | 169 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
170 | return -EINVAL; |
171 | } | |
172 | ||
173 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 174 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
175 | |
176 | return count; | |
177 | } | |
178 | ||
179 | static ssize_t store_up_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 | ||
3fc54d37 | 186 | mutex_lock(&dbs_mutex); |
b82fbe6c | 187 | if (ret != 1 || input > 100 || input <= dbs_tuners_ins.down_threshold) { |
3fc54d37 | 188 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
189 | return -EINVAL; |
190 | } | |
191 | ||
192 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 193 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
194 | |
195 | return count; | |
196 | } | |
197 | ||
198 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, | |
199 | const char *buf, size_t count) | |
200 | { | |
201 | unsigned int input; | |
202 | int ret; | |
203 | ret = sscanf (buf, "%u", &input); | |
204 | ||
3fc54d37 | 205 | mutex_lock(&dbs_mutex); |
b82fbe6c | 206 | if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) { |
3fc54d37 | 207 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
208 | return -EINVAL; |
209 | } | |
210 | ||
211 | dbs_tuners_ins.down_threshold = input; | |
3fc54d37 | 212 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
213 | |
214 | return count; | |
215 | } | |
216 | ||
001893cd | 217 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
b9170836 DJ |
218 | const char *buf, size_t count) |
219 | { | |
220 | unsigned int input; | |
221 | int ret; | |
222 | ||
223 | unsigned int j; | |
224 | ||
225 | ret = sscanf (buf, "%u", &input); | |
226 | if ( ret != 1 ) | |
227 | return -EINVAL; | |
228 | ||
229 | if ( input > 1 ) | |
230 | input = 1; | |
231 | ||
3fc54d37 | 232 | mutex_lock(&dbs_mutex); |
b9170836 | 233 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
3fc54d37 | 234 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
235 | return count; |
236 | } | |
237 | dbs_tuners_ins.ignore_nice = input; | |
238 | ||
239 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
dac1c1a5 | 240 | for_each_online_cpu(j) { |
b9170836 DJ |
241 | struct cpu_dbs_info_s *j_dbs_info; |
242 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
dac1c1a5 | 243 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
b9170836 DJ |
244 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
245 | } | |
3fc54d37 | 246 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
247 | |
248 | return count; | |
249 | } | |
250 | ||
251 | static ssize_t store_freq_step(struct cpufreq_policy *policy, | |
252 | const char *buf, size_t count) | |
253 | { | |
254 | unsigned int input; | |
255 | int ret; | |
256 | ||
257 | ret = sscanf (buf, "%u", &input); | |
258 | ||
259 | if ( ret != 1 ) | |
260 | return -EINVAL; | |
261 | ||
262 | if ( input > 100 ) | |
263 | input = 100; | |
264 | ||
265 | /* no need to test here if freq_step is zero as the user might actually | |
266 | * want this, they would be crazy though :) */ | |
3fc54d37 | 267 | mutex_lock(&dbs_mutex); |
b9170836 | 268 | dbs_tuners_ins.freq_step = input; |
3fc54d37 | 269 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
270 | |
271 | return count; | |
272 | } | |
273 | ||
274 | #define define_one_rw(_name) \ | |
275 | static struct freq_attr _name = \ | |
276 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
277 | ||
278 | define_one_rw(sampling_rate); | |
279 | define_one_rw(sampling_down_factor); | |
280 | define_one_rw(up_threshold); | |
281 | define_one_rw(down_threshold); | |
001893cd | 282 | define_one_rw(ignore_nice_load); |
b9170836 DJ |
283 | define_one_rw(freq_step); |
284 | ||
285 | static struct attribute * dbs_attributes[] = { | |
286 | &sampling_rate_max.attr, | |
287 | &sampling_rate_min.attr, | |
288 | &sampling_rate.attr, | |
289 | &sampling_down_factor.attr, | |
290 | &up_threshold.attr, | |
291 | &down_threshold.attr, | |
001893cd | 292 | &ignore_nice_load.attr, |
b9170836 DJ |
293 | &freq_step.attr, |
294 | NULL | |
295 | }; | |
296 | ||
297 | static struct attribute_group dbs_attr_group = { | |
298 | .attrs = dbs_attributes, | |
299 | .name = "conservative", | |
300 | }; | |
301 | ||
302 | /************************** sysfs end ************************/ | |
303 | ||
304 | static void dbs_check_cpu(int cpu) | |
305 | { | |
306 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; | |
08a28e2e | 307 | unsigned int tmp_idle_ticks, total_idle_ticks; |
b9170836 DJ |
308 | unsigned int freq_step; |
309 | unsigned int freq_down_sampling_rate; | |
08a28e2e | 310 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
b9170836 | 311 | struct cpufreq_policy *policy; |
b9170836 | 312 | |
b9170836 DJ |
313 | if (!this_dbs_info->enable) |
314 | return; | |
315 | ||
08a28e2e AC |
316 | policy = this_dbs_info->cur_policy; |
317 | ||
b9170836 DJ |
318 | /* |
319 | * The default safe range is 20% to 80% | |
320 | * Every sampling_rate, we check | |
321 | * - If current idle time is less than 20%, then we try to | |
322 | * increase frequency | |
323 | * Every sampling_rate*sampling_down_factor, we check | |
324 | * - If current idle time is more than 80%, then we try to | |
325 | * decrease frequency | |
326 | * | |
327 | * Any frequency increase takes it to the maximum frequency. | |
328 | * Frequency reduction happens at minimum steps of | |
329 | * 5% (default) of max_frequency | |
330 | */ | |
331 | ||
332 | /* Check for frequency increase */ | |
9c7d269b | 333 | idle_ticks = UINT_MAX; |
b9170836 | 334 | |
08a28e2e AC |
335 | /* Check for frequency increase */ |
336 | total_idle_ticks = get_cpu_idle_time(cpu); | |
337 | tmp_idle_ticks = total_idle_ticks - | |
338 | this_dbs_info->prev_cpu_idle_up; | |
339 | this_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
340 | ||
341 | if (tmp_idle_ticks < idle_ticks) | |
342 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
343 | |
344 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
345 | idle_ticks *= 100; | |
346 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
2c906b31 | 347 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
b9170836 DJ |
348 | |
349 | if (idle_ticks < up_idle_ticks) { | |
a159b827 | 350 | this_dbs_info->down_skip = 0; |
08a28e2e AC |
351 | this_dbs_info->prev_cpu_idle_down = |
352 | this_dbs_info->prev_cpu_idle_up; | |
790d76fa | 353 | |
b9170836 | 354 | /* if we are already at full speed then break out early */ |
a159b827 | 355 | if (this_dbs_info->requested_freq == policy->max) |
b9170836 DJ |
356 | return; |
357 | ||
358 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
359 | ||
360 | /* max freq cannot be less than 100. But who knows.... */ | |
361 | if (unlikely(freq_step == 0)) | |
362 | freq_step = 5; | |
363 | ||
a159b827 AC |
364 | this_dbs_info->requested_freq += freq_step; |
365 | if (this_dbs_info->requested_freq > policy->max) | |
366 | this_dbs_info->requested_freq = policy->max; | |
b9170836 | 367 | |
a159b827 | 368 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
b9170836 | 369 | CPUFREQ_RELATION_H); |
b9170836 DJ |
370 | return; |
371 | } | |
372 | ||
373 | /* Check for frequency decrease */ | |
a159b827 AC |
374 | this_dbs_info->down_skip++; |
375 | if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor) | |
b9170836 DJ |
376 | return; |
377 | ||
08a28e2e AC |
378 | /* Check for frequency decrease */ |
379 | total_idle_ticks = this_dbs_info->prev_cpu_idle_up; | |
380 | tmp_idle_ticks = total_idle_ticks - | |
381 | this_dbs_info->prev_cpu_idle_down; | |
382 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
b9170836 | 383 | |
08a28e2e AC |
384 | if (tmp_idle_ticks < idle_ticks) |
385 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
386 | |
387 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
388 | idle_ticks *= 100; | |
a159b827 | 389 | this_dbs_info->down_skip = 0; |
b9170836 DJ |
390 | |
391 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * | |
392 | dbs_tuners_ins.sampling_down_factor; | |
393 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * | |
2c906b31 | 394 | usecs_to_jiffies(freq_down_sampling_rate); |
b9170836 | 395 | |
9c7d269b | 396 | if (idle_ticks > down_idle_ticks) { |
2c906b31 AC |
397 | /* |
398 | * if we are already at the lowest speed then break out early | |
b9170836 | 399 | * or if we 'cannot' reduce the speed as the user might want |
2c906b31 AC |
400 | * freq_step to be zero |
401 | */ | |
a159b827 | 402 | if (this_dbs_info->requested_freq == policy->min |
b9170836 DJ |
403 | || dbs_tuners_ins.freq_step == 0) |
404 | return; | |
405 | ||
406 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
407 | ||
408 | /* max freq cannot be less than 100. But who knows.... */ | |
409 | if (unlikely(freq_step == 0)) | |
410 | freq_step = 5; | |
411 | ||
a159b827 AC |
412 | this_dbs_info->requested_freq -= freq_step; |
413 | if (this_dbs_info->requested_freq < policy->min) | |
414 | this_dbs_info->requested_freq = policy->min; | |
b9170836 | 415 | |
a159b827 | 416 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
2c906b31 | 417 | CPUFREQ_RELATION_H); |
b9170836 DJ |
418 | return; |
419 | } | |
420 | } | |
421 | ||
422 | static void do_dbs_timer(void *data) | |
423 | { | |
424 | int i; | |
4ec223d0 | 425 | lock_cpu_hotplug(); |
3fc54d37 | 426 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
427 | for_each_online_cpu(i) |
428 | dbs_check_cpu(i); | |
429 | schedule_delayed_work(&dbs_work, | |
430 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
3fc54d37 | 431 | mutex_unlock(&dbs_mutex); |
4ec223d0 | 432 | unlock_cpu_hotplug(); |
b9170836 DJ |
433 | } |
434 | ||
435 | static inline void dbs_timer_init(void) | |
436 | { | |
437 | INIT_WORK(&dbs_work, do_dbs_timer, NULL); | |
438 | schedule_delayed_work(&dbs_work, | |
439 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
440 | return; | |
441 | } | |
442 | ||
443 | static inline void dbs_timer_exit(void) | |
444 | { | |
445 | cancel_delayed_work(&dbs_work); | |
446 | return; | |
447 | } | |
448 | ||
449 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
450 | unsigned int event) | |
451 | { | |
452 | unsigned int cpu = policy->cpu; | |
453 | struct cpu_dbs_info_s *this_dbs_info; | |
454 | unsigned int j; | |
455 | ||
456 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
457 | ||
458 | switch (event) { | |
459 | case CPUFREQ_GOV_START: | |
460 | if ((!cpu_online(cpu)) || | |
461 | (!policy->cur)) | |
462 | return -EINVAL; | |
463 | ||
464 | if (policy->cpuinfo.transition_latency > | |
465 | (TRANSITION_LATENCY_LIMIT * 1000)) | |
466 | return -EINVAL; | |
467 | if (this_dbs_info->enable) /* Already enabled */ | |
468 | break; | |
469 | ||
3fc54d37 | 470 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
471 | for_each_cpu_mask(j, policy->cpus) { |
472 | struct cpu_dbs_info_s *j_dbs_info; | |
473 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
474 | j_dbs_info->cur_policy = policy; | |
475 | ||
08a28e2e | 476 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(cpu); |
b9170836 DJ |
477 | j_dbs_info->prev_cpu_idle_down |
478 | = j_dbs_info->prev_cpu_idle_up; | |
479 | } | |
480 | this_dbs_info->enable = 1; | |
a159b827 AC |
481 | this_dbs_info->down_skip = 0; |
482 | this_dbs_info->requested_freq = policy->cur; | |
b9170836 DJ |
483 | sysfs_create_group(&policy->kobj, &dbs_attr_group); |
484 | dbs_enable++; | |
485 | /* | |
486 | * Start the timerschedule work, when this governor | |
487 | * is used for first time | |
488 | */ | |
489 | if (dbs_enable == 1) { | |
490 | unsigned int latency; | |
491 | /* policy latency is in nS. Convert it to uS first */ | |
2c906b31 AC |
492 | latency = policy->cpuinfo.transition_latency / 1000; |
493 | if (latency == 0) | |
494 | latency = 1; | |
b9170836 | 495 | |
e8a02572 | 496 | def_sampling_rate = 10 * latency * |
b9170836 | 497 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
2c906b31 AC |
498 | |
499 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
500 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
501 | ||
b9170836 | 502 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
b9170836 DJ |
503 | |
504 | dbs_timer_init(); | |
505 | } | |
506 | ||
3fc54d37 | 507 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
508 | break; |
509 | ||
510 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 511 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
512 | this_dbs_info->enable = 0; |
513 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); | |
514 | dbs_enable--; | |
515 | /* | |
516 | * Stop the timerschedule work, when this governor | |
517 | * is used for first time | |
518 | */ | |
519 | if (dbs_enable == 0) | |
520 | dbs_timer_exit(); | |
521 | ||
3fc54d37 | 522 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
523 | |
524 | break; | |
525 | ||
526 | case CPUFREQ_GOV_LIMITS: | |
4ec223d0 | 527 | lock_cpu_hotplug(); |
3fc54d37 | 528 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
529 | if (policy->max < this_dbs_info->cur_policy->cur) |
530 | __cpufreq_driver_target( | |
531 | this_dbs_info->cur_policy, | |
532 | policy->max, CPUFREQ_RELATION_H); | |
533 | else if (policy->min > this_dbs_info->cur_policy->cur) | |
534 | __cpufreq_driver_target( | |
535 | this_dbs_info->cur_policy, | |
536 | policy->min, CPUFREQ_RELATION_L); | |
3fc54d37 | 537 | mutex_unlock(&dbs_mutex); |
4ec223d0 | 538 | unlock_cpu_hotplug(); |
b9170836 DJ |
539 | break; |
540 | } | |
541 | return 0; | |
542 | } | |
543 | ||
544 | static struct cpufreq_governor cpufreq_gov_dbs = { | |
545 | .name = "conservative", | |
546 | .governor = cpufreq_governor_dbs, | |
547 | .owner = THIS_MODULE, | |
548 | }; | |
549 | ||
550 | static int __init cpufreq_gov_dbs_init(void) | |
551 | { | |
552 | return cpufreq_register_governor(&cpufreq_gov_dbs); | |
553 | } | |
554 | ||
555 | static void __exit cpufreq_gov_dbs_exit(void) | |
556 | { | |
557 | /* Make sure that the scheduled work is indeed not running */ | |
558 | flush_scheduled_work(); | |
559 | ||
560 | cpufreq_unregister_governor(&cpufreq_gov_dbs); | |
561 | } | |
562 | ||
563 | ||
564 | MODULE_AUTHOR ("Alexander Clouter <alex-kernel@digriz.org.uk>"); | |
565 | MODULE_DESCRIPTION ("'cpufreq_conservative' - A dynamic cpufreq governor for " | |
566 | "Low Latency Frequency Transition capable processors " | |
567 | "optimised for use in a battery environment"); | |
568 | MODULE_LICENSE ("GPL"); | |
569 | ||
570 | module_init(cpufreq_gov_dbs_init); | |
571 | module_exit(cpufreq_gov_dbs_exit); |