Commit | Line | Data |
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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> | |
138a0128 | 25 | #include <linux/cpu.h> |
b9170836 DJ |
26 | #include <linux/sched.h> |
27 | #include <linux/kmod.h> | |
28 | #include <linux/workqueue.h> | |
29 | #include <linux/jiffies.h> | |
30 | #include <linux/kernel_stat.h> | |
31 | #include <linux/percpu.h> | |
3fc54d37 | 32 | #include <linux/mutex.h> |
b9170836 DJ |
33 | /* |
34 | * dbs is used in this file as a shortform for demandbased switching | |
35 | * It helps to keep variable names smaller, simpler | |
36 | */ | |
37 | ||
38 | #define DEF_FREQUENCY_UP_THRESHOLD (80) | |
b9170836 | 39 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
b9170836 DJ |
40 | |
41 | /* | |
42 | * The polling frequency of this governor depends on the capability of | |
43 | * the processor. Default polling frequency is 1000 times the transition | |
44 | * latency of the processor. The governor will work on any processor with | |
45 | * transition latency <= 10mS, using appropriate sampling | |
46 | * rate. | |
e08f5f5b GS |
47 | * For CPUs with transition latency > 10mS (mostly drivers |
48 | * with CPUFREQ_ETERNAL), this governor will not work. | |
b9170836 DJ |
49 | * All times here are in uS. |
50 | */ | |
51 | static unsigned int def_sampling_rate; | |
2c906b31 AC |
52 | #define MIN_SAMPLING_RATE_RATIO (2) |
53 | /* for correct statistics, we need at least 10 ticks between each measure */ | |
e08f5f5b GS |
54 | #define MIN_STAT_SAMPLING_RATE \ |
55 | (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) | |
56 | #define MIN_SAMPLING_RATE \ | |
57 | (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) | |
b9170836 | 58 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
2c906b31 AC |
59 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) |
60 | #define DEF_SAMPLING_DOWN_FACTOR (1) | |
61 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
b9170836 DJ |
62 | #define TRANSITION_LATENCY_LIMIT (10 * 1000) |
63 | ||
64 | static void do_dbs_timer(void *data); | |
65 | ||
66 | struct cpu_dbs_info_s { | |
67 | struct cpufreq_policy *cur_policy; | |
68 | unsigned int prev_cpu_idle_up; | |
69 | unsigned int prev_cpu_idle_down; | |
70 | unsigned int enable; | |
a159b827 AC |
71 | unsigned int down_skip; |
72 | unsigned int requested_freq; | |
b9170836 DJ |
73 | }; |
74 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); | |
75 | ||
76 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
77 | ||
4ec223d0 VP |
78 | /* |
79 | * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug | |
80 | * lock and dbs_mutex. cpu_hotplug lock should always be held before | |
81 | * dbs_mutex. If any function that can potentially take cpu_hotplug lock | |
82 | * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then | |
83 | * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock | |
84 | * is recursive for the same process. -Venki | |
85 | */ | |
3fc54d37 | 86 | static DEFINE_MUTEX (dbs_mutex); |
b9170836 DJ |
87 | static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); |
88 | ||
89 | struct dbs_tuners { | |
90 | unsigned int sampling_rate; | |
91 | unsigned int sampling_down_factor; | |
92 | unsigned int up_threshold; | |
93 | unsigned int down_threshold; | |
94 | unsigned int ignore_nice; | |
95 | unsigned int freq_step; | |
96 | }; | |
97 | ||
98 | static struct dbs_tuners dbs_tuners_ins = { | |
99 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, | |
100 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, | |
101 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
c326e27e MD |
102 | .ignore_nice = 0, |
103 | .freq_step = 5, | |
b9170836 DJ |
104 | }; |
105 | ||
dac1c1a5 DJ |
106 | static inline unsigned int get_cpu_idle_time(unsigned int cpu) |
107 | { | |
e08f5f5b GS |
108 | unsigned int add_nice = 0, ret; |
109 | ||
110 | if (dbs_tuners_ins.ignore_nice) | |
111 | add_nice = kstat_cpu(cpu).cpustat.nice; | |
112 | ||
113 | ret = kstat_cpu(cpu).cpustat.idle + | |
dac1c1a5 | 114 | kstat_cpu(cpu).cpustat.iowait + |
e08f5f5b GS |
115 | add_nice; |
116 | ||
117 | return ret; | |
dac1c1a5 DJ |
118 | } |
119 | ||
b9170836 DJ |
120 | /************************** sysfs interface ************************/ |
121 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
122 | { | |
123 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); | |
124 | } | |
125 | ||
126 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
127 | { | |
128 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); | |
129 | } | |
130 | ||
131 | #define define_one_ro(_name) \ | |
132 | static struct freq_attr _name = \ | |
133 | __ATTR(_name, 0444, show_##_name, NULL) | |
134 | ||
135 | define_one_ro(sampling_rate_max); | |
136 | define_one_ro(sampling_rate_min); | |
137 | ||
138 | /* cpufreq_conservative Governor Tunables */ | |
139 | #define show_one(file_name, object) \ | |
140 | static ssize_t show_##file_name \ | |
141 | (struct cpufreq_policy *unused, char *buf) \ | |
142 | { \ | |
143 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
144 | } | |
145 | show_one(sampling_rate, sampling_rate); | |
146 | show_one(sampling_down_factor, sampling_down_factor); | |
147 | show_one(up_threshold, up_threshold); | |
148 | show_one(down_threshold, down_threshold); | |
001893cd | 149 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
150 | show_one(freq_step, freq_step); |
151 | ||
152 | static ssize_t store_sampling_down_factor(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); | |
2c906b31 | 158 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
159 | return -EINVAL; |
160 | ||
3fc54d37 | 161 | mutex_lock(&dbs_mutex); |
b9170836 | 162 | dbs_tuners_ins.sampling_down_factor = input; |
3fc54d37 | 163 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
164 | |
165 | return count; | |
166 | } | |
167 | ||
168 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, | |
169 | const char *buf, size_t count) | |
170 | { | |
171 | unsigned int input; | |
172 | int ret; | |
173 | ret = sscanf (buf, "%u", &input); | |
174 | ||
3fc54d37 | 175 | mutex_lock(&dbs_mutex); |
b9170836 | 176 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
3fc54d37 | 177 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
178 | return -EINVAL; |
179 | } | |
180 | ||
181 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 182 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
183 | |
184 | return count; | |
185 | } | |
186 | ||
187 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, | |
188 | const char *buf, size_t count) | |
189 | { | |
190 | unsigned int input; | |
191 | int ret; | |
192 | ret = sscanf (buf, "%u", &input); | |
193 | ||
3fc54d37 | 194 | mutex_lock(&dbs_mutex); |
b82fbe6c | 195 | if (ret != 1 || input > 100 || input <= dbs_tuners_ins.down_threshold) { |
3fc54d37 | 196 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
197 | return -EINVAL; |
198 | } | |
199 | ||
200 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 201 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
202 | |
203 | return count; | |
204 | } | |
205 | ||
206 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, | |
207 | const char *buf, size_t count) | |
208 | { | |
209 | unsigned int input; | |
210 | int ret; | |
211 | ret = sscanf (buf, "%u", &input); | |
212 | ||
3fc54d37 | 213 | mutex_lock(&dbs_mutex); |
b82fbe6c | 214 | if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) { |
3fc54d37 | 215 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
216 | return -EINVAL; |
217 | } | |
218 | ||
219 | dbs_tuners_ins.down_threshold = input; | |
3fc54d37 | 220 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
221 | |
222 | return count; | |
223 | } | |
224 | ||
001893cd | 225 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
b9170836 DJ |
226 | const char *buf, size_t count) |
227 | { | |
228 | unsigned int input; | |
229 | int ret; | |
230 | ||
231 | unsigned int j; | |
232 | ||
233 | ret = sscanf (buf, "%u", &input); | |
234 | if ( ret != 1 ) | |
235 | return -EINVAL; | |
236 | ||
237 | if ( input > 1 ) | |
238 | input = 1; | |
239 | ||
3fc54d37 | 240 | mutex_lock(&dbs_mutex); |
b9170836 | 241 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
3fc54d37 | 242 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
243 | return count; |
244 | } | |
245 | dbs_tuners_ins.ignore_nice = input; | |
246 | ||
247 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
dac1c1a5 | 248 | for_each_online_cpu(j) { |
b9170836 DJ |
249 | struct cpu_dbs_info_s *j_dbs_info; |
250 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
dac1c1a5 | 251 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
b9170836 DJ |
252 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
253 | } | |
3fc54d37 | 254 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
255 | |
256 | return count; | |
257 | } | |
258 | ||
259 | static ssize_t store_freq_step(struct cpufreq_policy *policy, | |
260 | const char *buf, size_t count) | |
261 | { | |
262 | unsigned int input; | |
263 | int ret; | |
264 | ||
265 | ret = sscanf (buf, "%u", &input); | |
266 | ||
267 | if ( ret != 1 ) | |
268 | return -EINVAL; | |
269 | ||
270 | if ( input > 100 ) | |
271 | input = 100; | |
272 | ||
273 | /* no need to test here if freq_step is zero as the user might actually | |
274 | * want this, they would be crazy though :) */ | |
3fc54d37 | 275 | mutex_lock(&dbs_mutex); |
b9170836 | 276 | dbs_tuners_ins.freq_step = input; |
3fc54d37 | 277 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
278 | |
279 | return count; | |
280 | } | |
281 | ||
282 | #define define_one_rw(_name) \ | |
283 | static struct freq_attr _name = \ | |
284 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
285 | ||
286 | define_one_rw(sampling_rate); | |
287 | define_one_rw(sampling_down_factor); | |
288 | define_one_rw(up_threshold); | |
289 | define_one_rw(down_threshold); | |
001893cd | 290 | define_one_rw(ignore_nice_load); |
b9170836 DJ |
291 | define_one_rw(freq_step); |
292 | ||
293 | static struct attribute * dbs_attributes[] = { | |
294 | &sampling_rate_max.attr, | |
295 | &sampling_rate_min.attr, | |
296 | &sampling_rate.attr, | |
297 | &sampling_down_factor.attr, | |
298 | &up_threshold.attr, | |
299 | &down_threshold.attr, | |
001893cd | 300 | &ignore_nice_load.attr, |
b9170836 DJ |
301 | &freq_step.attr, |
302 | NULL | |
303 | }; | |
304 | ||
305 | static struct attribute_group dbs_attr_group = { | |
306 | .attrs = dbs_attributes, | |
307 | .name = "conservative", | |
308 | }; | |
309 | ||
310 | /************************** sysfs end ************************/ | |
311 | ||
312 | static void dbs_check_cpu(int cpu) | |
313 | { | |
314 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; | |
08a28e2e | 315 | unsigned int tmp_idle_ticks, total_idle_ticks; |
b9170836 DJ |
316 | unsigned int freq_step; |
317 | unsigned int freq_down_sampling_rate; | |
08a28e2e | 318 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
b9170836 | 319 | struct cpufreq_policy *policy; |
b9170836 | 320 | |
b9170836 DJ |
321 | if (!this_dbs_info->enable) |
322 | return; | |
323 | ||
08a28e2e AC |
324 | policy = this_dbs_info->cur_policy; |
325 | ||
b9170836 DJ |
326 | /* |
327 | * The default safe range is 20% to 80% | |
328 | * Every sampling_rate, we check | |
329 | * - If current idle time is less than 20%, then we try to | |
330 | * increase frequency | |
331 | * Every sampling_rate*sampling_down_factor, we check | |
332 | * - If current idle time is more than 80%, then we try to | |
333 | * decrease frequency | |
334 | * | |
335 | * Any frequency increase takes it to the maximum frequency. | |
336 | * Frequency reduction happens at minimum steps of | |
337 | * 5% (default) of max_frequency | |
338 | */ | |
339 | ||
340 | /* Check for frequency increase */ | |
9c7d269b | 341 | idle_ticks = UINT_MAX; |
b9170836 | 342 | |
08a28e2e AC |
343 | /* Check for frequency increase */ |
344 | total_idle_ticks = get_cpu_idle_time(cpu); | |
345 | tmp_idle_ticks = total_idle_ticks - | |
346 | this_dbs_info->prev_cpu_idle_up; | |
347 | this_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
348 | ||
349 | if (tmp_idle_ticks < idle_ticks) | |
350 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
351 | |
352 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
353 | idle_ticks *= 100; | |
354 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
2c906b31 | 355 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
b9170836 DJ |
356 | |
357 | if (idle_ticks < up_idle_ticks) { | |
a159b827 | 358 | this_dbs_info->down_skip = 0; |
08a28e2e AC |
359 | this_dbs_info->prev_cpu_idle_down = |
360 | this_dbs_info->prev_cpu_idle_up; | |
790d76fa | 361 | |
b9170836 | 362 | /* if we are already at full speed then break out early */ |
a159b827 | 363 | if (this_dbs_info->requested_freq == policy->max) |
b9170836 DJ |
364 | return; |
365 | ||
366 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
367 | ||
368 | /* max freq cannot be less than 100. But who knows.... */ | |
369 | if (unlikely(freq_step == 0)) | |
370 | freq_step = 5; | |
371 | ||
a159b827 AC |
372 | this_dbs_info->requested_freq += freq_step; |
373 | if (this_dbs_info->requested_freq > policy->max) | |
374 | this_dbs_info->requested_freq = policy->max; | |
b9170836 | 375 | |
a159b827 | 376 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
b9170836 | 377 | CPUFREQ_RELATION_H); |
b9170836 DJ |
378 | return; |
379 | } | |
380 | ||
381 | /* Check for frequency decrease */ | |
a159b827 AC |
382 | this_dbs_info->down_skip++; |
383 | if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor) | |
b9170836 DJ |
384 | return; |
385 | ||
08a28e2e AC |
386 | /* Check for frequency decrease */ |
387 | total_idle_ticks = this_dbs_info->prev_cpu_idle_up; | |
388 | tmp_idle_ticks = total_idle_ticks - | |
389 | this_dbs_info->prev_cpu_idle_down; | |
390 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
b9170836 | 391 | |
08a28e2e AC |
392 | if (tmp_idle_ticks < idle_ticks) |
393 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
394 | |
395 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
396 | idle_ticks *= 100; | |
a159b827 | 397 | this_dbs_info->down_skip = 0; |
b9170836 DJ |
398 | |
399 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * | |
400 | dbs_tuners_ins.sampling_down_factor; | |
401 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * | |
2c906b31 | 402 | usecs_to_jiffies(freq_down_sampling_rate); |
b9170836 | 403 | |
9c7d269b | 404 | if (idle_ticks > down_idle_ticks) { |
2c906b31 AC |
405 | /* |
406 | * if we are already at the lowest speed then break out early | |
b9170836 | 407 | * or if we 'cannot' reduce the speed as the user might want |
2c906b31 AC |
408 | * freq_step to be zero |
409 | */ | |
a159b827 | 410 | if (this_dbs_info->requested_freq == policy->min |
b9170836 DJ |
411 | || dbs_tuners_ins.freq_step == 0) |
412 | return; | |
413 | ||
414 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
415 | ||
416 | /* max freq cannot be less than 100. But who knows.... */ | |
417 | if (unlikely(freq_step == 0)) | |
418 | freq_step = 5; | |
419 | ||
a159b827 AC |
420 | this_dbs_info->requested_freq -= freq_step; |
421 | if (this_dbs_info->requested_freq < policy->min) | |
422 | this_dbs_info->requested_freq = policy->min; | |
b9170836 | 423 | |
a159b827 | 424 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
2c906b31 | 425 | CPUFREQ_RELATION_H); |
b9170836 DJ |
426 | return; |
427 | } | |
428 | } | |
429 | ||
430 | static void do_dbs_timer(void *data) | |
431 | { | |
432 | int i; | |
4ec223d0 | 433 | lock_cpu_hotplug(); |
3fc54d37 | 434 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
435 | for_each_online_cpu(i) |
436 | dbs_check_cpu(i); | |
437 | schedule_delayed_work(&dbs_work, | |
438 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
3fc54d37 | 439 | mutex_unlock(&dbs_mutex); |
4ec223d0 | 440 | unlock_cpu_hotplug(); |
b9170836 DJ |
441 | } |
442 | ||
443 | static inline void dbs_timer_init(void) | |
444 | { | |
445 | INIT_WORK(&dbs_work, do_dbs_timer, NULL); | |
446 | schedule_delayed_work(&dbs_work, | |
447 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
448 | return; | |
449 | } | |
450 | ||
451 | static inline void dbs_timer_exit(void) | |
452 | { | |
453 | cancel_delayed_work(&dbs_work); | |
454 | return; | |
455 | } | |
456 | ||
457 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
458 | unsigned int event) | |
459 | { | |
460 | unsigned int cpu = policy->cpu; | |
461 | struct cpu_dbs_info_s *this_dbs_info; | |
462 | unsigned int j; | |
914f7c31 | 463 | int rc; |
b9170836 DJ |
464 | |
465 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
466 | ||
467 | switch (event) { | |
468 | case CPUFREQ_GOV_START: | |
469 | if ((!cpu_online(cpu)) || | |
470 | (!policy->cur)) | |
471 | return -EINVAL; | |
472 | ||
473 | if (policy->cpuinfo.transition_latency > | |
474 | (TRANSITION_LATENCY_LIMIT * 1000)) | |
475 | return -EINVAL; | |
476 | if (this_dbs_info->enable) /* Already enabled */ | |
477 | break; | |
478 | ||
3fc54d37 | 479 | mutex_lock(&dbs_mutex); |
914f7c31 JG |
480 | |
481 | rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
482 | if (rc) { | |
483 | mutex_unlock(&dbs_mutex); | |
484 | return rc; | |
485 | } | |
486 | ||
b9170836 DJ |
487 | for_each_cpu_mask(j, policy->cpus) { |
488 | struct cpu_dbs_info_s *j_dbs_info; | |
489 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
490 | j_dbs_info->cur_policy = policy; | |
491 | ||
08a28e2e | 492 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(cpu); |
b9170836 DJ |
493 | j_dbs_info->prev_cpu_idle_down |
494 | = j_dbs_info->prev_cpu_idle_up; | |
495 | } | |
496 | this_dbs_info->enable = 1; | |
a159b827 AC |
497 | this_dbs_info->down_skip = 0; |
498 | this_dbs_info->requested_freq = policy->cur; | |
914f7c31 | 499 | |
b9170836 DJ |
500 | dbs_enable++; |
501 | /* | |
502 | * Start the timerschedule work, when this governor | |
503 | * is used for first time | |
504 | */ | |
505 | if (dbs_enable == 1) { | |
506 | unsigned int latency; | |
507 | /* policy latency is in nS. Convert it to uS first */ | |
2c906b31 AC |
508 | latency = policy->cpuinfo.transition_latency / 1000; |
509 | if (latency == 0) | |
510 | latency = 1; | |
b9170836 | 511 | |
e8a02572 | 512 | def_sampling_rate = 10 * latency * |
b9170836 | 513 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
2c906b31 AC |
514 | |
515 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
516 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
517 | ||
b9170836 | 518 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
b9170836 DJ |
519 | |
520 | dbs_timer_init(); | |
521 | } | |
522 | ||
3fc54d37 | 523 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
524 | break; |
525 | ||
526 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 527 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
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 | ||
3fc54d37 | 538 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
539 | |
540 | break; | |
541 | ||
542 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 543 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
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); | |
3fc54d37 | 552 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
553 | break; |
554 | } | |
555 | return 0; | |
556 | } | |
557 | ||
558 | static struct cpufreq_governor cpufreq_gov_dbs = { | |
559 | .name = "conservative", | |
560 | .governor = cpufreq_governor_dbs, | |
561 | .owner = THIS_MODULE, | |
562 | }; | |
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 ("Alexander Clouter <alex-kernel@digriz.org.uk>"); | |
579 | MODULE_DESCRIPTION ("'cpufreq_conservative' - A dynamic cpufreq governor for " | |
580 | "Low Latency Frequency Transition capable processors " | |
581 | "optimised for use in a battery environment"); | |
582 | MODULE_LICENSE ("GPL"); | |
583 | ||
584 | module_init(cpufreq_gov_dbs_init); | |
585 | module_exit(cpufreq_gov_dbs_exit); |