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/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. | |
e08f5f5b GS |
46 | * For CPUs with transition latency > 10mS (mostly drivers |
47 | * with CPUFREQ_ETERNAL), this governor will not work. | |
b9170836 DJ |
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 */ | |
e08f5f5b GS |
53 | #define MIN_STAT_SAMPLING_RATE \ |
54 | (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) | |
55 | #define MIN_SAMPLING_RATE \ | |
56 | (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) | |
b9170836 | 57 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
2c906b31 AC |
58 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) |
59 | #define DEF_SAMPLING_DOWN_FACTOR (1) | |
60 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
1c256245 | 61 | #define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000) |
b9170836 | 62 | |
c4028958 | 63 | static void do_dbs_timer(struct work_struct *work); |
b9170836 DJ |
64 | |
65 | struct cpu_dbs_info_s { | |
66 | struct cpufreq_policy *cur_policy; | |
67 | unsigned int prev_cpu_idle_up; | |
68 | unsigned int prev_cpu_idle_down; | |
69 | unsigned int enable; | |
a159b827 AC |
70 | unsigned int down_skip; |
71 | unsigned int requested_freq; | |
b9170836 DJ |
72 | }; |
73 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); | |
74 | ||
75 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
76 | ||
4ec223d0 VP |
77 | /* |
78 | * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug | |
79 | * lock and dbs_mutex. cpu_hotplug lock should always be held before | |
80 | * dbs_mutex. If any function that can potentially take cpu_hotplug lock | |
81 | * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then | |
82 | * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock | |
83 | * is recursive for the same process. -Venki | |
84 | */ | |
3fc54d37 | 85 | static DEFINE_MUTEX (dbs_mutex); |
c4028958 | 86 | static DECLARE_DELAYED_WORK(dbs_work, do_dbs_timer); |
b9170836 DJ |
87 | |
88 | struct dbs_tuners { | |
89 | unsigned int sampling_rate; | |
90 | unsigned int sampling_down_factor; | |
91 | unsigned int up_threshold; | |
92 | unsigned int down_threshold; | |
93 | unsigned int ignore_nice; | |
94 | unsigned int freq_step; | |
95 | }; | |
96 | ||
97 | static struct dbs_tuners dbs_tuners_ins = { | |
98 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, | |
99 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, | |
100 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
c326e27e MD |
101 | .ignore_nice = 0, |
102 | .freq_step = 5, | |
b9170836 DJ |
103 | }; |
104 | ||
dac1c1a5 DJ |
105 | static inline unsigned int get_cpu_idle_time(unsigned int cpu) |
106 | { | |
e08f5f5b GS |
107 | unsigned int add_nice = 0, ret; |
108 | ||
109 | if (dbs_tuners_ins.ignore_nice) | |
110 | add_nice = kstat_cpu(cpu).cpustat.nice; | |
111 | ||
112 | ret = kstat_cpu(cpu).cpustat.idle + | |
dac1c1a5 | 113 | kstat_cpu(cpu).cpustat.iowait + |
e08f5f5b GS |
114 | add_nice; |
115 | ||
116 | return ret; | |
dac1c1a5 DJ |
117 | } |
118 | ||
b9170836 DJ |
119 | /************************** sysfs interface ************************/ |
120 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
121 | { | |
122 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); | |
123 | } | |
124 | ||
125 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
126 | { | |
127 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); | |
128 | } | |
129 | ||
130 | #define define_one_ro(_name) \ | |
131 | static struct freq_attr _name = \ | |
132 | __ATTR(_name, 0444, show_##_name, NULL) | |
133 | ||
134 | define_one_ro(sampling_rate_max); | |
135 | define_one_ro(sampling_rate_min); | |
136 | ||
137 | /* cpufreq_conservative Governor Tunables */ | |
138 | #define show_one(file_name, object) \ | |
139 | static ssize_t show_##file_name \ | |
140 | (struct cpufreq_policy *unused, char *buf) \ | |
141 | { \ | |
142 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
143 | } | |
144 | show_one(sampling_rate, sampling_rate); | |
145 | show_one(sampling_down_factor, sampling_down_factor); | |
146 | show_one(up_threshold, up_threshold); | |
147 | show_one(down_threshold, down_threshold); | |
001893cd | 148 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
149 | show_one(freq_step, freq_step); |
150 | ||
151 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, | |
152 | const char *buf, size_t count) | |
153 | { | |
154 | unsigned int input; | |
155 | int ret; | |
156 | ret = sscanf (buf, "%u", &input); | |
2c906b31 | 157 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
158 | return -EINVAL; |
159 | ||
3fc54d37 | 160 | mutex_lock(&dbs_mutex); |
b9170836 | 161 | dbs_tuners_ins.sampling_down_factor = input; |
3fc54d37 | 162 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
163 | |
164 | return count; | |
165 | } | |
166 | ||
167 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, | |
168 | const char *buf, size_t count) | |
169 | { | |
170 | unsigned int input; | |
171 | int ret; | |
172 | ret = sscanf (buf, "%u", &input); | |
173 | ||
3fc54d37 | 174 | mutex_lock(&dbs_mutex); |
b9170836 | 175 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
3fc54d37 | 176 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
177 | return -EINVAL; |
178 | } | |
179 | ||
180 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 181 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
182 | |
183 | return count; | |
184 | } | |
185 | ||
186 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, | |
187 | const char *buf, size_t count) | |
188 | { | |
189 | unsigned int input; | |
190 | int ret; | |
191 | ret = sscanf (buf, "%u", &input); | |
192 | ||
3fc54d37 | 193 | mutex_lock(&dbs_mutex); |
b82fbe6c | 194 | if (ret != 1 || input > 100 || input <= dbs_tuners_ins.down_threshold) { |
3fc54d37 | 195 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
196 | return -EINVAL; |
197 | } | |
198 | ||
199 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 200 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
201 | |
202 | return count; | |
203 | } | |
204 | ||
205 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, | |
206 | const char *buf, size_t count) | |
207 | { | |
208 | unsigned int input; | |
209 | int ret; | |
210 | ret = sscanf (buf, "%u", &input); | |
211 | ||
3fc54d37 | 212 | mutex_lock(&dbs_mutex); |
b82fbe6c | 213 | if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) { |
3fc54d37 | 214 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
215 | return -EINVAL; |
216 | } | |
217 | ||
218 | dbs_tuners_ins.down_threshold = input; | |
3fc54d37 | 219 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
220 | |
221 | return count; | |
222 | } | |
223 | ||
001893cd | 224 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
b9170836 DJ |
225 | const char *buf, size_t count) |
226 | { | |
227 | unsigned int input; | |
228 | int ret; | |
229 | ||
230 | unsigned int j; | |
231 | ||
232 | ret = sscanf (buf, "%u", &input); | |
233 | if ( ret != 1 ) | |
234 | return -EINVAL; | |
235 | ||
236 | if ( input > 1 ) | |
237 | input = 1; | |
238 | ||
3fc54d37 | 239 | mutex_lock(&dbs_mutex); |
b9170836 | 240 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
3fc54d37 | 241 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
242 | return count; |
243 | } | |
244 | dbs_tuners_ins.ignore_nice = input; | |
245 | ||
246 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
dac1c1a5 | 247 | for_each_online_cpu(j) { |
b9170836 DJ |
248 | struct cpu_dbs_info_s *j_dbs_info; |
249 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
dac1c1a5 | 250 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
b9170836 DJ |
251 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
252 | } | |
3fc54d37 | 253 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
254 | |
255 | return count; | |
256 | } | |
257 | ||
258 | static ssize_t store_freq_step(struct cpufreq_policy *policy, | |
259 | const char *buf, size_t count) | |
260 | { | |
261 | unsigned int input; | |
262 | int ret; | |
263 | ||
264 | ret = sscanf (buf, "%u", &input); | |
265 | ||
266 | if ( ret != 1 ) | |
267 | return -EINVAL; | |
268 | ||
269 | if ( input > 100 ) | |
270 | input = 100; | |
271 | ||
272 | /* no need to test here if freq_step is zero as the user might actually | |
273 | * want this, they would be crazy though :) */ | |
3fc54d37 | 274 | mutex_lock(&dbs_mutex); |
b9170836 | 275 | dbs_tuners_ins.freq_step = input; |
3fc54d37 | 276 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
277 | |
278 | return count; | |
279 | } | |
280 | ||
281 | #define define_one_rw(_name) \ | |
282 | static struct freq_attr _name = \ | |
283 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
284 | ||
285 | define_one_rw(sampling_rate); | |
286 | define_one_rw(sampling_down_factor); | |
287 | define_one_rw(up_threshold); | |
288 | define_one_rw(down_threshold); | |
001893cd | 289 | define_one_rw(ignore_nice_load); |
b9170836 DJ |
290 | define_one_rw(freq_step); |
291 | ||
292 | static struct attribute * dbs_attributes[] = { | |
293 | &sampling_rate_max.attr, | |
294 | &sampling_rate_min.attr, | |
295 | &sampling_rate.attr, | |
296 | &sampling_down_factor.attr, | |
297 | &up_threshold.attr, | |
298 | &down_threshold.attr, | |
001893cd | 299 | &ignore_nice_load.attr, |
b9170836 DJ |
300 | &freq_step.attr, |
301 | NULL | |
302 | }; | |
303 | ||
304 | static struct attribute_group dbs_attr_group = { | |
305 | .attrs = dbs_attributes, | |
306 | .name = "conservative", | |
307 | }; | |
308 | ||
309 | /************************** sysfs end ************************/ | |
310 | ||
311 | static void dbs_check_cpu(int cpu) | |
312 | { | |
313 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; | |
08a28e2e | 314 | unsigned int tmp_idle_ticks, total_idle_ticks; |
b9170836 DJ |
315 | unsigned int freq_step; |
316 | unsigned int freq_down_sampling_rate; | |
08a28e2e | 317 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
b9170836 | 318 | struct cpufreq_policy *policy; |
b9170836 | 319 | |
b9170836 DJ |
320 | if (!this_dbs_info->enable) |
321 | return; | |
322 | ||
08a28e2e AC |
323 | policy = this_dbs_info->cur_policy; |
324 | ||
b9170836 DJ |
325 | /* |
326 | * The default safe range is 20% to 80% | |
327 | * Every sampling_rate, we check | |
328 | * - If current idle time is less than 20%, then we try to | |
329 | * increase frequency | |
330 | * Every sampling_rate*sampling_down_factor, we check | |
331 | * - If current idle time is more than 80%, then we try to | |
332 | * decrease frequency | |
333 | * | |
334 | * Any frequency increase takes it to the maximum frequency. | |
335 | * Frequency reduction happens at minimum steps of | |
336 | * 5% (default) of max_frequency | |
337 | */ | |
338 | ||
339 | /* Check for frequency increase */ | |
9c7d269b | 340 | idle_ticks = UINT_MAX; |
b9170836 | 341 | |
08a28e2e AC |
342 | /* Check for frequency increase */ |
343 | total_idle_ticks = get_cpu_idle_time(cpu); | |
344 | tmp_idle_ticks = total_idle_ticks - | |
345 | this_dbs_info->prev_cpu_idle_up; | |
346 | this_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
347 | ||
348 | if (tmp_idle_ticks < idle_ticks) | |
349 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
350 | |
351 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
352 | idle_ticks *= 100; | |
353 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
2c906b31 | 354 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
b9170836 DJ |
355 | |
356 | if (idle_ticks < up_idle_ticks) { | |
a159b827 | 357 | this_dbs_info->down_skip = 0; |
08a28e2e AC |
358 | this_dbs_info->prev_cpu_idle_down = |
359 | this_dbs_info->prev_cpu_idle_up; | |
790d76fa | 360 | |
b9170836 | 361 | /* if we are already at full speed then break out early */ |
a159b827 | 362 | if (this_dbs_info->requested_freq == policy->max) |
b9170836 DJ |
363 | return; |
364 | ||
365 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
366 | ||
367 | /* max freq cannot be less than 100. But who knows.... */ | |
368 | if (unlikely(freq_step == 0)) | |
369 | freq_step = 5; | |
370 | ||
a159b827 AC |
371 | this_dbs_info->requested_freq += freq_step; |
372 | if (this_dbs_info->requested_freq > policy->max) | |
373 | this_dbs_info->requested_freq = policy->max; | |
b9170836 | 374 | |
a159b827 | 375 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
b9170836 | 376 | CPUFREQ_RELATION_H); |
b9170836 DJ |
377 | return; |
378 | } | |
379 | ||
380 | /* Check for frequency decrease */ | |
a159b827 AC |
381 | this_dbs_info->down_skip++; |
382 | if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor) | |
b9170836 DJ |
383 | return; |
384 | ||
08a28e2e AC |
385 | /* Check for frequency decrease */ |
386 | total_idle_ticks = this_dbs_info->prev_cpu_idle_up; | |
387 | tmp_idle_ticks = total_idle_ticks - | |
388 | this_dbs_info->prev_cpu_idle_down; | |
389 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
b9170836 | 390 | |
08a28e2e AC |
391 | if (tmp_idle_ticks < idle_ticks) |
392 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
393 | |
394 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
395 | idle_ticks *= 100; | |
a159b827 | 396 | this_dbs_info->down_skip = 0; |
b9170836 DJ |
397 | |
398 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * | |
399 | dbs_tuners_ins.sampling_down_factor; | |
400 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * | |
2c906b31 | 401 | usecs_to_jiffies(freq_down_sampling_rate); |
b9170836 | 402 | |
9c7d269b | 403 | if (idle_ticks > down_idle_ticks) { |
2c906b31 AC |
404 | /* |
405 | * if we are already at the lowest speed then break out early | |
b9170836 | 406 | * or if we 'cannot' reduce the speed as the user might want |
2c906b31 AC |
407 | * freq_step to be zero |
408 | */ | |
a159b827 | 409 | if (this_dbs_info->requested_freq == policy->min |
b9170836 DJ |
410 | || dbs_tuners_ins.freq_step == 0) |
411 | return; | |
412 | ||
413 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
414 | ||
415 | /* max freq cannot be less than 100. But who knows.... */ | |
416 | if (unlikely(freq_step == 0)) | |
417 | freq_step = 5; | |
418 | ||
a159b827 AC |
419 | this_dbs_info->requested_freq -= freq_step; |
420 | if (this_dbs_info->requested_freq < policy->min) | |
421 | this_dbs_info->requested_freq = policy->min; | |
b9170836 | 422 | |
a159b827 | 423 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
2c906b31 | 424 | CPUFREQ_RELATION_H); |
b9170836 DJ |
425 | return; |
426 | } | |
427 | } | |
428 | ||
c4028958 | 429 | static void do_dbs_timer(struct work_struct *work) |
b9170836 DJ |
430 | { |
431 | int i; | |
3fc54d37 | 432 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
433 | for_each_online_cpu(i) |
434 | dbs_check_cpu(i); | |
435 | schedule_delayed_work(&dbs_work, | |
436 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
3fc54d37 | 437 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
438 | } |
439 | ||
440 | static inline void dbs_timer_init(void) | |
441 | { | |
b9170836 DJ |
442 | schedule_delayed_work(&dbs_work, |
443 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
444 | return; | |
445 | } | |
446 | ||
447 | static inline void dbs_timer_exit(void) | |
448 | { | |
449 | cancel_delayed_work(&dbs_work); | |
450 | return; | |
451 | } | |
452 | ||
453 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
454 | unsigned int event) | |
455 | { | |
456 | unsigned int cpu = policy->cpu; | |
457 | struct cpu_dbs_info_s *this_dbs_info; | |
458 | unsigned int j; | |
914f7c31 | 459 | int rc; |
b9170836 DJ |
460 | |
461 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
462 | ||
463 | switch (event) { | |
464 | case CPUFREQ_GOV_START: | |
465 | if ((!cpu_online(cpu)) || | |
466 | (!policy->cur)) | |
467 | return -EINVAL; | |
468 | ||
b9170836 DJ |
469 | if (this_dbs_info->enable) /* Already enabled */ |
470 | break; | |
471 | ||
3fc54d37 | 472 | mutex_lock(&dbs_mutex); |
914f7c31 JG |
473 | |
474 | rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
475 | if (rc) { | |
476 | mutex_unlock(&dbs_mutex); | |
477 | return rc; | |
478 | } | |
479 | ||
b9170836 DJ |
480 | for_each_cpu_mask(j, policy->cpus) { |
481 | struct cpu_dbs_info_s *j_dbs_info; | |
482 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
483 | j_dbs_info->cur_policy = policy; | |
484 | ||
08a28e2e | 485 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(cpu); |
b9170836 DJ |
486 | j_dbs_info->prev_cpu_idle_down |
487 | = j_dbs_info->prev_cpu_idle_up; | |
488 | } | |
489 | this_dbs_info->enable = 1; | |
a159b827 AC |
490 | this_dbs_info->down_skip = 0; |
491 | this_dbs_info->requested_freq = policy->cur; | |
914f7c31 | 492 | |
b9170836 DJ |
493 | dbs_enable++; |
494 | /* | |
495 | * Start the timerschedule work, when this governor | |
496 | * is used for first time | |
497 | */ | |
498 | if (dbs_enable == 1) { | |
499 | unsigned int latency; | |
500 | /* policy latency is in nS. Convert it to uS first */ | |
2c906b31 AC |
501 | latency = policy->cpuinfo.transition_latency / 1000; |
502 | if (latency == 0) | |
503 | latency = 1; | |
b9170836 | 504 | |
e8a02572 | 505 | def_sampling_rate = 10 * latency * |
b9170836 | 506 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
2c906b31 AC |
507 | |
508 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
509 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
510 | ||
b9170836 | 511 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
b9170836 DJ |
512 | |
513 | dbs_timer_init(); | |
514 | } | |
515 | ||
3fc54d37 | 516 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
517 | break; |
518 | ||
519 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 520 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
521 | this_dbs_info->enable = 0; |
522 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); | |
523 | dbs_enable--; | |
524 | /* | |
525 | * Stop the timerschedule work, when this governor | |
526 | * is used for first time | |
527 | */ | |
528 | if (dbs_enable == 0) | |
529 | dbs_timer_exit(); | |
530 | ||
3fc54d37 | 531 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
532 | |
533 | break; | |
534 | ||
535 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 536 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
537 | if (policy->max < this_dbs_info->cur_policy->cur) |
538 | __cpufreq_driver_target( | |
539 | this_dbs_info->cur_policy, | |
540 | policy->max, CPUFREQ_RELATION_H); | |
541 | else if (policy->min > this_dbs_info->cur_policy->cur) | |
542 | __cpufreq_driver_target( | |
543 | this_dbs_info->cur_policy, | |
544 | policy->min, CPUFREQ_RELATION_L); | |
3fc54d37 | 545 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
546 | break; |
547 | } | |
548 | return 0; | |
549 | } | |
550 | ||
1c256245 TR |
551 | struct cpufreq_governor cpufreq_gov_conservative = { |
552 | .name = "conservative", | |
553 | .governor = cpufreq_governor_dbs, | |
554 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, | |
555 | .owner = THIS_MODULE, | |
b9170836 | 556 | }; |
1c256245 | 557 | EXPORT_SYMBOL(cpufreq_gov_conservative); |
b9170836 DJ |
558 | |
559 | static int __init cpufreq_gov_dbs_init(void) | |
560 | { | |
1c256245 | 561 | return cpufreq_register_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
562 | } |
563 | ||
564 | static void __exit cpufreq_gov_dbs_exit(void) | |
565 | { | |
566 | /* Make sure that the scheduled work is indeed not running */ | |
567 | flush_scheduled_work(); | |
568 | ||
1c256245 | 569 | cpufreq_unregister_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
570 | } |
571 | ||
572 | ||
573 | MODULE_AUTHOR ("Alexander Clouter <alex-kernel@digriz.org.uk>"); | |
574 | MODULE_DESCRIPTION ("'cpufreq_conservative' - A dynamic cpufreq governor for " | |
575 | "Low Latency Frequency Transition capable processors " | |
576 | "optimised for use in a battery environment"); | |
577 | MODULE_LICENSE ("GPL"); | |
578 | ||
579 | module_init(cpufreq_gov_dbs_init); | |
580 | module_exit(cpufreq_gov_dbs_exit); |