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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> | |
3fc54d37 | 30 | #include <linux/mutex.h> |
1da177e4 LT |
31 | |
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) | |
c29f1403 | 38 | #define MIN_FREQUENCY_UP_THRESHOLD (11) |
1da177e4 LT |
39 | #define MAX_FREQUENCY_UP_THRESHOLD (100) |
40 | ||
32ee8c3e DJ |
41 | /* |
42 | * The polling frequency of this governor depends on the capability of | |
1da177e4 | 43 | * the processor. Default polling frequency is 1000 times the transition |
32ee8c3e DJ |
44 | * latency of the processor. The governor will work on any processor with |
45 | * transition latency <= 10mS, using appropriate sampling | |
1da177e4 LT |
46 | * rate. |
47 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) | |
48 | * this governor will not work. | |
49 | * All times here are in uS. | |
50 | */ | |
32ee8c3e | 51 | static unsigned int def_sampling_rate; |
df8b59be DJ |
52 | #define MIN_SAMPLING_RATE_RATIO (2) |
53 | /* for correct statistics, we need at least 10 ticks between each measure */ | |
54 | #define MIN_STAT_SAMPLING_RATE (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) | |
55 | #define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO) | |
1da177e4 LT |
56 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
57 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000) | |
e131832c DJ |
58 | #define DEF_SAMPLING_DOWN_FACTOR (1) |
59 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
1da177e4 | 60 | #define TRANSITION_LATENCY_LIMIT (10 * 1000) |
1da177e4 LT |
61 | |
62 | static void do_dbs_timer(void *data); | |
63 | ||
64 | struct cpu_dbs_info_s { | |
32ee8c3e DJ |
65 | struct cpufreq_policy *cur_policy; |
66 | unsigned int prev_cpu_idle_up; | |
67 | unsigned int prev_cpu_idle_down; | |
68 | unsigned int enable; | |
1da177e4 LT |
69 | }; |
70 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); | |
71 | ||
72 | static unsigned int dbs_enable; /* number of CPUs using this policy */ | |
73 | ||
32ee8c3e | 74 | static DEFINE_MUTEX (dbs_mutex); |
1da177e4 LT |
75 | static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); |
76 | ||
77 | struct dbs_tuners { | |
32ee8c3e DJ |
78 | unsigned int sampling_rate; |
79 | unsigned int sampling_down_factor; | |
80 | unsigned int up_threshold; | |
81 | unsigned int ignore_nice; | |
1da177e4 LT |
82 | }; |
83 | ||
84 | static struct dbs_tuners dbs_tuners_ins = { | |
32ee8c3e DJ |
85 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
86 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
9cbad61b | 87 | .ignore_nice = 0, |
1da177e4 LT |
88 | }; |
89 | ||
dac1c1a5 DJ |
90 | static inline unsigned int get_cpu_idle_time(unsigned int cpu) |
91 | { | |
92 | return kstat_cpu(cpu).cpustat.idle + | |
93 | kstat_cpu(cpu).cpustat.iowait + | |
001893cd | 94 | ( dbs_tuners_ins.ignore_nice ? |
dac1c1a5 DJ |
95 | kstat_cpu(cpu).cpustat.nice : |
96 | 0); | |
97 | } | |
98 | ||
1da177e4 LT |
99 | /************************** sysfs interface ************************/ |
100 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
101 | { | |
102 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); | |
103 | } | |
104 | ||
105 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
106 | { | |
107 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); | |
108 | } | |
109 | ||
32ee8c3e DJ |
110 | #define define_one_ro(_name) \ |
111 | static struct freq_attr _name = \ | |
1da177e4 LT |
112 | __ATTR(_name, 0444, show_##_name, NULL) |
113 | ||
114 | define_one_ro(sampling_rate_max); | |
115 | define_one_ro(sampling_rate_min); | |
116 | ||
117 | /* cpufreq_ondemand Governor Tunables */ | |
118 | #define show_one(file_name, object) \ | |
119 | static ssize_t show_##file_name \ | |
120 | (struct cpufreq_policy *unused, char *buf) \ | |
121 | { \ | |
122 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
123 | } | |
124 | show_one(sampling_rate, sampling_rate); | |
125 | show_one(sampling_down_factor, sampling_down_factor); | |
126 | show_one(up_threshold, up_threshold); | |
001893cd | 127 | show_one(ignore_nice_load, ignore_nice); |
1da177e4 | 128 | |
32ee8c3e | 129 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, |
1da177e4 LT |
130 | const char *buf, size_t count) |
131 | { | |
132 | unsigned int input; | |
133 | int ret; | |
134 | ret = sscanf (buf, "%u", &input); | |
135 | if (ret != 1 ) | |
136 | return -EINVAL; | |
137 | ||
e131832c DJ |
138 | if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
139 | return -EINVAL; | |
140 | ||
3fc54d37 | 141 | mutex_lock(&dbs_mutex); |
1da177e4 | 142 | dbs_tuners_ins.sampling_down_factor = input; |
3fc54d37 | 143 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
144 | |
145 | return count; | |
146 | } | |
147 | ||
32ee8c3e | 148 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
1da177e4 LT |
149 | const char *buf, size_t count) |
150 | { | |
151 | unsigned int input; | |
152 | int ret; | |
153 | ret = sscanf (buf, "%u", &input); | |
154 | ||
3fc54d37 | 155 | mutex_lock(&dbs_mutex); |
1da177e4 | 156 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
3fc54d37 | 157 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
158 | return -EINVAL; |
159 | } | |
160 | ||
161 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 162 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
163 | |
164 | return count; | |
165 | } | |
166 | ||
32ee8c3e | 167 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
1da177e4 LT |
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); |
32ee8c3e | 175 | if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || |
c29f1403 | 176 | input < MIN_FREQUENCY_UP_THRESHOLD) { |
3fc54d37 | 177 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
178 | return -EINVAL; |
179 | } | |
180 | ||
181 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 182 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
183 | |
184 | return count; | |
185 | } | |
186 | ||
001893cd | 187 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
3d5ee9e5 DJ |
188 | const char *buf, size_t count) |
189 | { | |
190 | unsigned int input; | |
191 | int ret; | |
192 | ||
193 | unsigned int j; | |
32ee8c3e | 194 | |
3d5ee9e5 DJ |
195 | ret = sscanf (buf, "%u", &input); |
196 | if ( ret != 1 ) | |
197 | return -EINVAL; | |
198 | ||
199 | if ( input > 1 ) | |
200 | input = 1; | |
32ee8c3e | 201 | |
3fc54d37 | 202 | mutex_lock(&dbs_mutex); |
3d5ee9e5 | 203 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
3fc54d37 | 204 | mutex_unlock(&dbs_mutex); |
3d5ee9e5 DJ |
205 | return count; |
206 | } | |
207 | dbs_tuners_ins.ignore_nice = input; | |
208 | ||
209 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
dac1c1a5 | 210 | for_each_online_cpu(j) { |
3d5ee9e5 DJ |
211 | struct cpu_dbs_info_s *j_dbs_info; |
212 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
dac1c1a5 | 213 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
3d5ee9e5 DJ |
214 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
215 | } | |
3fc54d37 | 216 | mutex_unlock(&dbs_mutex); |
3d5ee9e5 DJ |
217 | |
218 | return count; | |
219 | } | |
220 | ||
1da177e4 LT |
221 | #define define_one_rw(_name) \ |
222 | static struct freq_attr _name = \ | |
223 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
224 | ||
225 | define_one_rw(sampling_rate); | |
226 | define_one_rw(sampling_down_factor); | |
227 | define_one_rw(up_threshold); | |
001893cd | 228 | define_one_rw(ignore_nice_load); |
1da177e4 LT |
229 | |
230 | static struct attribute * dbs_attributes[] = { | |
231 | &sampling_rate_max.attr, | |
232 | &sampling_rate_min.attr, | |
233 | &sampling_rate.attr, | |
234 | &sampling_down_factor.attr, | |
235 | &up_threshold.attr, | |
001893cd | 236 | &ignore_nice_load.attr, |
1da177e4 LT |
237 | NULL |
238 | }; | |
239 | ||
240 | static struct attribute_group dbs_attr_group = { | |
241 | .attrs = dbs_attributes, | |
242 | .name = "ondemand", | |
243 | }; | |
244 | ||
245 | /************************** sysfs end ************************/ | |
246 | ||
247 | static void dbs_check_cpu(int cpu) | |
248 | { | |
c29f1403 DJ |
249 | unsigned int idle_ticks, up_idle_ticks, total_ticks; |
250 | unsigned int freq_next; | |
1da177e4 LT |
251 | unsigned int freq_down_sampling_rate; |
252 | static int down_skip[NR_CPUS]; | |
253 | struct cpu_dbs_info_s *this_dbs_info; | |
254 | ||
255 | struct cpufreq_policy *policy; | |
256 | unsigned int j; | |
257 | ||
258 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
259 | if (!this_dbs_info->enable) | |
260 | return; | |
261 | ||
262 | policy = this_dbs_info->cur_policy; | |
32ee8c3e | 263 | /* |
c29f1403 DJ |
264 | * Every sampling_rate, we check, if current idle time is less |
265 | * than 20% (default), then we try to increase frequency | |
266 | * Every sampling_rate*sampling_down_factor, we look for a the lowest | |
267 | * frequency which can sustain the load while keeping idle time over | |
268 | * 30%. If such a frequency exist, we try to decrease to this frequency. | |
1da177e4 | 269 | * |
32ee8c3e DJ |
270 | * Any frequency increase takes it to the maximum frequency. |
271 | * Frequency reduction happens at minimum steps of | |
272 | * 5% (default) of current frequency | |
1da177e4 LT |
273 | */ |
274 | ||
275 | /* Check for frequency increase */ | |
9c7d269b | 276 | idle_ticks = UINT_MAX; |
1da177e4 | 277 | for_each_cpu_mask(j, policy->cpus) { |
9c7d269b | 278 | unsigned int tmp_idle_ticks, total_idle_ticks; |
1da177e4 LT |
279 | struct cpu_dbs_info_s *j_dbs_info; |
280 | ||
1da177e4 | 281 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
dac1c1a5 | 282 | total_idle_ticks = get_cpu_idle_time(j); |
1da177e4 LT |
283 | tmp_idle_ticks = total_idle_ticks - |
284 | j_dbs_info->prev_cpu_idle_up; | |
285 | j_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
286 | ||
287 | if (tmp_idle_ticks < idle_ticks) | |
288 | idle_ticks = tmp_idle_ticks; | |
289 | } | |
290 | ||
291 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
292 | idle_ticks *= 100; | |
293 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
6fe71165 | 294 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
1da177e4 LT |
295 | |
296 | if (idle_ticks < up_idle_ticks) { | |
dac1c1a5 | 297 | down_skip[cpu] = 0; |
790d76fa DJ |
298 | for_each_cpu_mask(j, policy->cpus) { |
299 | struct cpu_dbs_info_s *j_dbs_info; | |
300 | ||
301 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
32ee8c3e | 302 | j_dbs_info->prev_cpu_idle_down = |
790d76fa DJ |
303 | j_dbs_info->prev_cpu_idle_up; |
304 | } | |
c11420a6 DJ |
305 | /* if we are already at full speed then break out early */ |
306 | if (policy->cur == policy->max) | |
307 | return; | |
32ee8c3e DJ |
308 | |
309 | __cpufreq_driver_target(policy, policy->max, | |
1da177e4 | 310 | CPUFREQ_RELATION_H); |
1da177e4 LT |
311 | return; |
312 | } | |
313 | ||
314 | /* Check for frequency decrease */ | |
315 | down_skip[cpu]++; | |
316 | if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor) | |
317 | return; | |
318 | ||
9c7d269b | 319 | idle_ticks = UINT_MAX; |
1da177e4 | 320 | for_each_cpu_mask(j, policy->cpus) { |
9c7d269b | 321 | unsigned int tmp_idle_ticks, total_idle_ticks; |
1da177e4 LT |
322 | struct cpu_dbs_info_s *j_dbs_info; |
323 | ||
1da177e4 | 324 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
dac1c1a5 DJ |
325 | /* Check for frequency decrease */ |
326 | total_idle_ticks = j_dbs_info->prev_cpu_idle_up; | |
1da177e4 LT |
327 | tmp_idle_ticks = total_idle_ticks - |
328 | j_dbs_info->prev_cpu_idle_down; | |
329 | j_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
330 | ||
331 | if (tmp_idle_ticks < idle_ticks) | |
332 | idle_ticks = tmp_idle_ticks; | |
333 | } | |
334 | ||
1da177e4 | 335 | down_skip[cpu] = 0; |
c29f1403 DJ |
336 | /* if we cannot reduce the frequency anymore, break out early */ |
337 | if (policy->cur == policy->min) | |
338 | return; | |
1da177e4 | 339 | |
c29f1403 | 340 | /* Compute how many ticks there are between two measurements */ |
1da177e4 LT |
341 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * |
342 | dbs_tuners_ins.sampling_down_factor; | |
c29f1403 | 343 | total_ticks = usecs_to_jiffies(freq_down_sampling_rate); |
1206aaac | 344 | |
c29f1403 DJ |
345 | /* |
346 | * The optimal frequency is the frequency that is the lowest that | |
347 | * can support the current CPU usage without triggering the up | |
348 | * policy. To be safe, we focus 10 points under the threshold. | |
349 | */ | |
350 | freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks; | |
32ee8c3e | 351 | freq_next = (freq_next * policy->cur) / |
c29f1403 | 352 | (dbs_tuners_ins.up_threshold - 10); |
1da177e4 | 353 | |
7c9d8c0e DB |
354 | if (freq_next < policy->min) |
355 | freq_next = policy->min; | |
356 | ||
c29f1403 DJ |
357 | if (freq_next <= ((policy->cur * 95) / 100)) |
358 | __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L); | |
1da177e4 LT |
359 | } |
360 | ||
361 | static void do_dbs_timer(void *data) | |
32ee8c3e | 362 | { |
1da177e4 | 363 | int i; |
3fc54d37 | 364 | mutex_lock(&dbs_mutex); |
6fe71165 DJ |
365 | for_each_online_cpu(i) |
366 | dbs_check_cpu(i); | |
32ee8c3e | 367 | schedule_delayed_work(&dbs_work, |
6fe71165 | 368 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
3fc54d37 | 369 | mutex_unlock(&dbs_mutex); |
32ee8c3e | 370 | } |
1da177e4 LT |
371 | |
372 | static inline void dbs_timer_init(void) | |
373 | { | |
374 | INIT_WORK(&dbs_work, do_dbs_timer, NULL); | |
375 | schedule_delayed_work(&dbs_work, | |
6fe71165 | 376 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
1da177e4 LT |
377 | return; |
378 | } | |
379 | ||
380 | static inline void dbs_timer_exit(void) | |
381 | { | |
382 | cancel_delayed_work(&dbs_work); | |
383 | return; | |
384 | } | |
385 | ||
386 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
387 | unsigned int event) | |
388 | { | |
389 | unsigned int cpu = policy->cpu; | |
390 | struct cpu_dbs_info_s *this_dbs_info; | |
391 | unsigned int j; | |
392 | ||
393 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
394 | ||
395 | switch (event) { | |
396 | case CPUFREQ_GOV_START: | |
32ee8c3e | 397 | if ((!cpu_online(cpu)) || |
1da177e4 LT |
398 | (!policy->cur)) |
399 | return -EINVAL; | |
400 | ||
401 | if (policy->cpuinfo.transition_latency > | |
ff8c288d EP |
402 | (TRANSITION_LATENCY_LIMIT * 1000)) { |
403 | printk(KERN_WARNING "ondemand governor failed to load " | |
404 | "due to too long transition latency\n"); | |
1da177e4 | 405 | return -EINVAL; |
ff8c288d | 406 | } |
1da177e4 LT |
407 | if (this_dbs_info->enable) /* Already enabled */ |
408 | break; | |
32ee8c3e | 409 | |
3fc54d37 | 410 | mutex_lock(&dbs_mutex); |
1da177e4 LT |
411 | for_each_cpu_mask(j, policy->cpus) { |
412 | struct cpu_dbs_info_s *j_dbs_info; | |
413 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
414 | j_dbs_info->cur_policy = policy; | |
32ee8c3e | 415 | |
dac1c1a5 | 416 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
3d5ee9e5 DJ |
417 | j_dbs_info->prev_cpu_idle_down |
418 | = j_dbs_info->prev_cpu_idle_up; | |
1da177e4 LT |
419 | } |
420 | this_dbs_info->enable = 1; | |
421 | sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
422 | dbs_enable++; | |
423 | /* | |
424 | * Start the timerschedule work, when this governor | |
425 | * is used for first time | |
426 | */ | |
427 | if (dbs_enable == 1) { | |
428 | unsigned int latency; | |
429 | /* policy latency is in nS. Convert it to uS first */ | |
df8b59be DJ |
430 | latency = policy->cpuinfo.transition_latency / 1000; |
431 | if (latency == 0) | |
432 | latency = 1; | |
1da177e4 | 433 | |
df8b59be | 434 | def_sampling_rate = latency * |
1da177e4 | 435 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
df8b59be DJ |
436 | |
437 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
438 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
439 | ||
1da177e4 | 440 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
1da177e4 LT |
441 | dbs_timer_init(); |
442 | } | |
32ee8c3e | 443 | |
3fc54d37 | 444 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
445 | break; |
446 | ||
447 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 448 | mutex_lock(&dbs_mutex); |
1da177e4 LT |
449 | this_dbs_info->enable = 0; |
450 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); | |
451 | dbs_enable--; | |
452 | /* | |
453 | * Stop the timerschedule work, when this governor | |
454 | * is used for first time | |
455 | */ | |
32ee8c3e | 456 | if (dbs_enable == 0) |
1da177e4 | 457 | dbs_timer_exit(); |
32ee8c3e | 458 | |
3fc54d37 | 459 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
460 | |
461 | break; | |
462 | ||
463 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 464 | mutex_lock(&dbs_mutex); |
1da177e4 LT |
465 | if (policy->max < this_dbs_info->cur_policy->cur) |
466 | __cpufreq_driver_target( | |
467 | this_dbs_info->cur_policy, | |
32ee8c3e | 468 | policy->max, CPUFREQ_RELATION_H); |
1da177e4 LT |
469 | else if (policy->min > this_dbs_info->cur_policy->cur) |
470 | __cpufreq_driver_target( | |
471 | this_dbs_info->cur_policy, | |
32ee8c3e | 472 | policy->min, CPUFREQ_RELATION_L); |
3fc54d37 | 473 | mutex_unlock(&dbs_mutex); |
1da177e4 LT |
474 | break; |
475 | } | |
476 | return 0; | |
477 | } | |
478 | ||
7f335d4e | 479 | static struct cpufreq_governor cpufreq_gov_dbs = { |
1da177e4 LT |
480 | .name = "ondemand", |
481 | .governor = cpufreq_governor_dbs, | |
482 | .owner = THIS_MODULE, | |
483 | }; | |
1da177e4 LT |
484 | |
485 | static int __init cpufreq_gov_dbs_init(void) | |
486 | { | |
487 | return cpufreq_register_governor(&cpufreq_gov_dbs); | |
488 | } | |
489 | ||
490 | static void __exit cpufreq_gov_dbs_exit(void) | |
491 | { | |
492 | /* Make sure that the scheduled work is indeed not running */ | |
493 | flush_scheduled_work(); | |
494 | ||
495 | cpufreq_unregister_governor(&cpufreq_gov_dbs); | |
496 | } | |
497 | ||
498 | ||
499 | MODULE_AUTHOR ("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>"); | |
500 | MODULE_DESCRIPTION ("'cpufreq_ondemand' - A dynamic cpufreq governor for " | |
501 | "Low Latency Frequency Transition capable processors"); | |
502 | MODULE_LICENSE ("GPL"); | |
503 | ||
504 | module_init(cpufreq_gov_dbs_init); | |
505 | module_exit(cpufreq_gov_dbs_exit); |