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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 | 39 | |
18a7247d DJ |
40 | /* |
41 | * The polling frequency of this governor depends on the capability of | |
b9170836 | 42 | * the processor. Default polling frequency is 1000 times the transition |
18a7247d DJ |
43 | * latency of the processor. The governor will work on any processor with |
44 | * transition latency <= 10mS, using appropriate sampling | |
b9170836 | 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 | */ | |
18a7247d | 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 { | |
18a7247d DJ |
66 | struct cpufreq_policy *cur_policy; |
67 | unsigned int prev_cpu_idle_up; | |
68 | unsigned int prev_cpu_idle_down; | |
69 | unsigned int enable; | |
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 | */ | |
18a7247d | 85 | static DEFINE_MUTEX (dbs_mutex); |
c4028958 | 86 | static DECLARE_DELAYED_WORK(dbs_work, do_dbs_timer); |
b9170836 DJ |
87 | |
88 | struct dbs_tuners { | |
18a7247d DJ |
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; | |
b9170836 DJ |
95 | }; |
96 | ||
97 | static struct dbs_tuners dbs_tuners_ins = { | |
18a7247d DJ |
98 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
99 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, | |
100 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, | |
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 | ||
18a7247d | 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 | ||
a8d7c3bc EO |
119 | /* keep track of frequency transitions */ |
120 | static int | |
121 | dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, | |
122 | void *data) | |
123 | { | |
124 | struct cpufreq_freqs *freq = data; | |
125 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, | |
126 | freq->cpu); | |
127 | ||
128 | if (!this_dbs_info->enable) | |
129 | return 0; | |
130 | ||
131 | this_dbs_info->requested_freq = freq->new; | |
132 | ||
133 | return 0; | |
134 | } | |
135 | ||
136 | static struct notifier_block dbs_cpufreq_notifier_block = { | |
137 | .notifier_call = dbs_cpufreq_notifier | |
138 | }; | |
139 | ||
b9170836 DJ |
140 | /************************** sysfs interface ************************/ |
141 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) | |
142 | { | |
143 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); | |
144 | } | |
145 | ||
146 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
147 | { | |
148 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); | |
149 | } | |
150 | ||
18a7247d DJ |
151 | #define define_one_ro(_name) \ |
152 | static struct freq_attr _name = \ | |
b9170836 DJ |
153 | __ATTR(_name, 0444, show_##_name, NULL) |
154 | ||
155 | define_one_ro(sampling_rate_max); | |
156 | define_one_ro(sampling_rate_min); | |
157 | ||
158 | /* cpufreq_conservative Governor Tunables */ | |
159 | #define show_one(file_name, object) \ | |
160 | static ssize_t show_##file_name \ | |
161 | (struct cpufreq_policy *unused, char *buf) \ | |
162 | { \ | |
163 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
164 | } | |
165 | show_one(sampling_rate, sampling_rate); | |
166 | show_one(sampling_down_factor, sampling_down_factor); | |
167 | show_one(up_threshold, up_threshold); | |
168 | show_one(down_threshold, down_threshold); | |
001893cd | 169 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
170 | show_one(freq_step, freq_step); |
171 | ||
18a7247d | 172 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, |
b9170836 DJ |
173 | const char *buf, size_t count) |
174 | { | |
175 | unsigned int input; | |
176 | int ret; | |
177 | ret = sscanf (buf, "%u", &input); | |
2c906b31 | 178 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
179 | return -EINVAL; |
180 | ||
3fc54d37 | 181 | mutex_lock(&dbs_mutex); |
b9170836 | 182 | dbs_tuners_ins.sampling_down_factor = input; |
3fc54d37 | 183 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
184 | |
185 | return count; | |
186 | } | |
187 | ||
18a7247d | 188 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
b9170836 DJ |
189 | const char *buf, size_t count) |
190 | { | |
191 | unsigned int input; | |
192 | int ret; | |
193 | ret = sscanf (buf, "%u", &input); | |
194 | ||
3fc54d37 | 195 | mutex_lock(&dbs_mutex); |
b9170836 | 196 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
3fc54d37 | 197 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
198 | return -EINVAL; |
199 | } | |
200 | ||
201 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 202 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
203 | |
204 | return count; | |
205 | } | |
206 | ||
18a7247d | 207 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
b9170836 DJ |
208 | const char *buf, size_t count) |
209 | { | |
210 | unsigned int input; | |
211 | int ret; | |
212 | ret = sscanf (buf, "%u", &input); | |
213 | ||
3fc54d37 | 214 | mutex_lock(&dbs_mutex); |
b82fbe6c | 215 | if (ret != 1 || input > 100 || input <= dbs_tuners_ins.down_threshold) { |
3fc54d37 | 216 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
217 | return -EINVAL; |
218 | } | |
219 | ||
220 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 221 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
222 | |
223 | return count; | |
224 | } | |
225 | ||
18a7247d | 226 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, |
b9170836 DJ |
227 | const char *buf, size_t count) |
228 | { | |
229 | unsigned int input; | |
230 | int ret; | |
231 | ret = sscanf (buf, "%u", &input); | |
232 | ||
3fc54d37 | 233 | mutex_lock(&dbs_mutex); |
b82fbe6c | 234 | if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) { |
3fc54d37 | 235 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
236 | return -EINVAL; |
237 | } | |
238 | ||
239 | dbs_tuners_ins.down_threshold = input; | |
3fc54d37 | 240 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
241 | |
242 | return count; | |
243 | } | |
244 | ||
001893cd | 245 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
b9170836 DJ |
246 | const char *buf, size_t count) |
247 | { | |
248 | unsigned int input; | |
249 | int ret; | |
250 | ||
251 | unsigned int j; | |
18a7247d DJ |
252 | |
253 | ret = sscanf(buf, "%u", &input); | |
254 | if (ret != 1) | |
b9170836 DJ |
255 | return -EINVAL; |
256 | ||
18a7247d | 257 | if (input > 1) |
b9170836 | 258 | input = 1; |
18a7247d | 259 | |
3fc54d37 | 260 | mutex_lock(&dbs_mutex); |
18a7247d | 261 | if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */ |
3fc54d37 | 262 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
263 | return count; |
264 | } | |
265 | dbs_tuners_ins.ignore_nice = input; | |
266 | ||
267 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
dac1c1a5 | 268 | for_each_online_cpu(j) { |
b9170836 DJ |
269 | struct cpu_dbs_info_s *j_dbs_info; |
270 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
dac1c1a5 | 271 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
b9170836 DJ |
272 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
273 | } | |
3fc54d37 | 274 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
275 | |
276 | return count; | |
277 | } | |
278 | ||
279 | static ssize_t store_freq_step(struct cpufreq_policy *policy, | |
280 | const char *buf, size_t count) | |
281 | { | |
282 | unsigned int input; | |
283 | int ret; | |
284 | ||
18a7247d | 285 | ret = sscanf(buf, "%u", &input); |
b9170836 | 286 | |
18a7247d | 287 | if (ret != 1) |
b9170836 DJ |
288 | return -EINVAL; |
289 | ||
18a7247d | 290 | if (input > 100) |
b9170836 | 291 | input = 100; |
18a7247d | 292 | |
b9170836 DJ |
293 | /* no need to test here if freq_step is zero as the user might actually |
294 | * want this, they would be crazy though :) */ | |
3fc54d37 | 295 | mutex_lock(&dbs_mutex); |
b9170836 | 296 | dbs_tuners_ins.freq_step = input; |
3fc54d37 | 297 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
298 | |
299 | return count; | |
300 | } | |
301 | ||
302 | #define define_one_rw(_name) \ | |
303 | static struct freq_attr _name = \ | |
304 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
305 | ||
306 | define_one_rw(sampling_rate); | |
307 | define_one_rw(sampling_down_factor); | |
308 | define_one_rw(up_threshold); | |
309 | define_one_rw(down_threshold); | |
001893cd | 310 | define_one_rw(ignore_nice_load); |
b9170836 DJ |
311 | define_one_rw(freq_step); |
312 | ||
313 | static struct attribute * dbs_attributes[] = { | |
314 | &sampling_rate_max.attr, | |
315 | &sampling_rate_min.attr, | |
316 | &sampling_rate.attr, | |
317 | &sampling_down_factor.attr, | |
318 | &up_threshold.attr, | |
319 | &down_threshold.attr, | |
001893cd | 320 | &ignore_nice_load.attr, |
b9170836 DJ |
321 | &freq_step.attr, |
322 | NULL | |
323 | }; | |
324 | ||
325 | static struct attribute_group dbs_attr_group = { | |
326 | .attrs = dbs_attributes, | |
327 | .name = "conservative", | |
328 | }; | |
329 | ||
330 | /************************** sysfs end ************************/ | |
331 | ||
332 | static void dbs_check_cpu(int cpu) | |
333 | { | |
334 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; | |
08a28e2e | 335 | unsigned int tmp_idle_ticks, total_idle_ticks; |
b9170836 DJ |
336 | unsigned int freq_step; |
337 | unsigned int freq_down_sampling_rate; | |
08a28e2e | 338 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
b9170836 | 339 | struct cpufreq_policy *policy; |
b9170836 | 340 | |
b9170836 DJ |
341 | if (!this_dbs_info->enable) |
342 | return; | |
343 | ||
08a28e2e AC |
344 | policy = this_dbs_info->cur_policy; |
345 | ||
18a7247d DJ |
346 | /* |
347 | * The default safe range is 20% to 80% | |
b9170836 | 348 | * Every sampling_rate, we check |
18a7247d DJ |
349 | * - If current idle time is less than 20%, then we try to |
350 | * increase frequency | |
b9170836 | 351 | * Every sampling_rate*sampling_down_factor, we check |
18a7247d DJ |
352 | * - If current idle time is more than 80%, then we try to |
353 | * decrease frequency | |
b9170836 | 354 | * |
18a7247d DJ |
355 | * Any frequency increase takes it to the maximum frequency. |
356 | * Frequency reduction happens at minimum steps of | |
357 | * 5% (default) of max_frequency | |
b9170836 DJ |
358 | */ |
359 | ||
360 | /* Check for frequency increase */ | |
9c7d269b | 361 | idle_ticks = UINT_MAX; |
b9170836 | 362 | |
08a28e2e AC |
363 | /* Check for frequency increase */ |
364 | total_idle_ticks = get_cpu_idle_time(cpu); | |
365 | tmp_idle_ticks = total_idle_ticks - | |
366 | this_dbs_info->prev_cpu_idle_up; | |
367 | this_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
368 | ||
369 | if (tmp_idle_ticks < idle_ticks) | |
370 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
371 | |
372 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
373 | idle_ticks *= 100; | |
374 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
2c906b31 | 375 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
b9170836 DJ |
376 | |
377 | if (idle_ticks < up_idle_ticks) { | |
a159b827 | 378 | this_dbs_info->down_skip = 0; |
08a28e2e AC |
379 | this_dbs_info->prev_cpu_idle_down = |
380 | this_dbs_info->prev_cpu_idle_up; | |
790d76fa | 381 | |
b9170836 | 382 | /* if we are already at full speed then break out early */ |
a159b827 | 383 | if (this_dbs_info->requested_freq == policy->max) |
b9170836 | 384 | return; |
18a7247d | 385 | |
b9170836 DJ |
386 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; |
387 | ||
388 | /* max freq cannot be less than 100. But who knows.... */ | |
389 | if (unlikely(freq_step == 0)) | |
390 | freq_step = 5; | |
18a7247d | 391 | |
a159b827 AC |
392 | this_dbs_info->requested_freq += freq_step; |
393 | if (this_dbs_info->requested_freq > policy->max) | |
394 | this_dbs_info->requested_freq = policy->max; | |
b9170836 | 395 | |
a159b827 | 396 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
b9170836 | 397 | CPUFREQ_RELATION_H); |
b9170836 DJ |
398 | return; |
399 | } | |
400 | ||
401 | /* Check for frequency decrease */ | |
a159b827 AC |
402 | this_dbs_info->down_skip++; |
403 | if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor) | |
b9170836 DJ |
404 | return; |
405 | ||
08a28e2e AC |
406 | /* Check for frequency decrease */ |
407 | total_idle_ticks = this_dbs_info->prev_cpu_idle_up; | |
408 | tmp_idle_ticks = total_idle_ticks - | |
409 | this_dbs_info->prev_cpu_idle_down; | |
410 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
b9170836 | 411 | |
08a28e2e AC |
412 | if (tmp_idle_ticks < idle_ticks) |
413 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
414 | |
415 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
416 | idle_ticks *= 100; | |
a159b827 | 417 | this_dbs_info->down_skip = 0; |
b9170836 DJ |
418 | |
419 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * | |
420 | dbs_tuners_ins.sampling_down_factor; | |
421 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * | |
2c906b31 | 422 | usecs_to_jiffies(freq_down_sampling_rate); |
b9170836 | 423 | |
9c7d269b | 424 | if (idle_ticks > down_idle_ticks) { |
2c906b31 AC |
425 | /* |
426 | * if we are already at the lowest speed then break out early | |
b9170836 | 427 | * or if we 'cannot' reduce the speed as the user might want |
2c906b31 AC |
428 | * freq_step to be zero |
429 | */ | |
a159b827 | 430 | if (this_dbs_info->requested_freq == policy->min |
b9170836 DJ |
431 | || dbs_tuners_ins.freq_step == 0) |
432 | return; | |
433 | ||
434 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; | |
435 | ||
436 | /* max freq cannot be less than 100. But who knows.... */ | |
437 | if (unlikely(freq_step == 0)) | |
438 | freq_step = 5; | |
439 | ||
a159b827 AC |
440 | this_dbs_info->requested_freq -= freq_step; |
441 | if (this_dbs_info->requested_freq < policy->min) | |
442 | this_dbs_info->requested_freq = policy->min; | |
b9170836 | 443 | |
a159b827 | 444 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
2c906b31 | 445 | CPUFREQ_RELATION_H); |
b9170836 DJ |
446 | return; |
447 | } | |
448 | } | |
449 | ||
c4028958 | 450 | static void do_dbs_timer(struct work_struct *work) |
18a7247d | 451 | { |
b9170836 | 452 | int i; |
3fc54d37 | 453 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
454 | for_each_online_cpu(i) |
455 | dbs_check_cpu(i); | |
18a7247d | 456 | schedule_delayed_work(&dbs_work, |
b9170836 | 457 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
3fc54d37 | 458 | mutex_unlock(&dbs_mutex); |
18a7247d | 459 | } |
b9170836 DJ |
460 | |
461 | static inline void dbs_timer_init(void) | |
462 | { | |
b9170836 DJ |
463 | schedule_delayed_work(&dbs_work, |
464 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
465 | return; | |
466 | } | |
467 | ||
468 | static inline void dbs_timer_exit(void) | |
469 | { | |
470 | cancel_delayed_work(&dbs_work); | |
471 | return; | |
472 | } | |
473 | ||
474 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
475 | unsigned int event) | |
476 | { | |
477 | unsigned int cpu = policy->cpu; | |
478 | struct cpu_dbs_info_s *this_dbs_info; | |
479 | unsigned int j; | |
914f7c31 | 480 | int rc; |
b9170836 DJ |
481 | |
482 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
483 | ||
484 | switch (event) { | |
485 | case CPUFREQ_GOV_START: | |
18a7247d | 486 | if ((!cpu_online(cpu)) || (!policy->cur)) |
b9170836 DJ |
487 | return -EINVAL; |
488 | ||
b9170836 DJ |
489 | if (this_dbs_info->enable) /* Already enabled */ |
490 | break; | |
18a7247d | 491 | |
3fc54d37 | 492 | mutex_lock(&dbs_mutex); |
914f7c31 JG |
493 | |
494 | rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
495 | if (rc) { | |
496 | mutex_unlock(&dbs_mutex); | |
497 | return rc; | |
498 | } | |
499 | ||
b9170836 DJ |
500 | for_each_cpu_mask(j, policy->cpus) { |
501 | struct cpu_dbs_info_s *j_dbs_info; | |
502 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
503 | j_dbs_info->cur_policy = policy; | |
18a7247d | 504 | |
08a28e2e | 505 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(cpu); |
b9170836 DJ |
506 | j_dbs_info->prev_cpu_idle_down |
507 | = j_dbs_info->prev_cpu_idle_up; | |
508 | } | |
509 | this_dbs_info->enable = 1; | |
a159b827 AC |
510 | this_dbs_info->down_skip = 0; |
511 | this_dbs_info->requested_freq = policy->cur; | |
914f7c31 | 512 | |
b9170836 DJ |
513 | dbs_enable++; |
514 | /* | |
515 | * Start the timerschedule work, when this governor | |
516 | * is used for first time | |
517 | */ | |
518 | if (dbs_enable == 1) { | |
519 | unsigned int latency; | |
520 | /* policy latency is in nS. Convert it to uS first */ | |
2c906b31 AC |
521 | latency = policy->cpuinfo.transition_latency / 1000; |
522 | if (latency == 0) | |
523 | latency = 1; | |
b9170836 | 524 | |
e8a02572 | 525 | def_sampling_rate = 10 * latency * |
b9170836 | 526 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
2c906b31 AC |
527 | |
528 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
529 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
530 | ||
b9170836 | 531 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
b9170836 DJ |
532 | |
533 | dbs_timer_init(); | |
a8d7c3bc EO |
534 | cpufreq_register_notifier( |
535 | &dbs_cpufreq_notifier_block, | |
536 | CPUFREQ_TRANSITION_NOTIFIER); | |
b9170836 | 537 | } |
18a7247d | 538 | |
3fc54d37 | 539 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
540 | break; |
541 | ||
542 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 543 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
544 | this_dbs_info->enable = 0; |
545 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); | |
546 | dbs_enable--; | |
547 | /* | |
548 | * Stop the timerschedule work, when this governor | |
549 | * is used for first time | |
550 | */ | |
a8d7c3bc | 551 | if (dbs_enable == 0) { |
b9170836 | 552 | dbs_timer_exit(); |
a8d7c3bc EO |
553 | cpufreq_unregister_notifier( |
554 | &dbs_cpufreq_notifier_block, | |
555 | CPUFREQ_TRANSITION_NOTIFIER); | |
556 | } | |
557 | ||
3fc54d37 | 558 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
559 | |
560 | break; | |
561 | ||
562 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 563 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
564 | if (policy->max < this_dbs_info->cur_policy->cur) |
565 | __cpufreq_driver_target( | |
566 | this_dbs_info->cur_policy, | |
18a7247d | 567 | policy->max, CPUFREQ_RELATION_H); |
b9170836 DJ |
568 | else if (policy->min > this_dbs_info->cur_policy->cur) |
569 | __cpufreq_driver_target( | |
570 | this_dbs_info->cur_policy, | |
18a7247d | 571 | policy->min, CPUFREQ_RELATION_L); |
3fc54d37 | 572 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
573 | break; |
574 | } | |
575 | return 0; | |
576 | } | |
577 | ||
1c256245 TR |
578 | struct cpufreq_governor cpufreq_gov_conservative = { |
579 | .name = "conservative", | |
580 | .governor = cpufreq_governor_dbs, | |
581 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, | |
582 | .owner = THIS_MODULE, | |
b9170836 | 583 | }; |
1c256245 | 584 | EXPORT_SYMBOL(cpufreq_gov_conservative); |
b9170836 DJ |
585 | |
586 | static int __init cpufreq_gov_dbs_init(void) | |
587 | { | |
1c256245 | 588 | return cpufreq_register_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
589 | } |
590 | ||
591 | static void __exit cpufreq_gov_dbs_exit(void) | |
592 | { | |
593 | /* Make sure that the scheduled work is indeed not running */ | |
594 | flush_scheduled_work(); | |
595 | ||
1c256245 | 596 | cpufreq_unregister_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
597 | } |
598 | ||
599 | ||
600 | MODULE_AUTHOR ("Alexander Clouter <alex-kernel@digriz.org.uk>"); | |
601 | MODULE_DESCRIPTION ("'cpufreq_conservative' - A dynamic cpufreq governor for " | |
602 | "Low Latency Frequency Transition capable processors " | |
603 | "optimised for use in a battery environment"); | |
604 | MODULE_LICENSE ("GPL"); | |
605 | ||
6915719b JW |
606 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
607 | fs_initcall(cpufreq_gov_dbs_init); | |
608 | #else | |
b9170836 | 609 | module_init(cpufreq_gov_dbs_init); |
6915719b | 610 | #endif |
b9170836 | 611 | module_exit(cpufreq_gov_dbs_exit); |