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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 | */ | |
9acef487 | 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 | { | |
9411b4ef TR |
143 | static int print_once; |
144 | ||
145 | if (!print_once) { | |
146 | printk(KERN_INFO "CPUFREQ: conservative sampling_rate_max " | |
147 | "sysfs file is deprecated - used by: %s\n", | |
148 | current->comm); | |
149 | print_once = 1; | |
150 | } | |
9acef487 | 151 | return sprintf(buf, "%u\n", MAX_SAMPLING_RATE); |
b9170836 DJ |
152 | } |
153 | ||
154 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) | |
155 | { | |
9411b4ef TR |
156 | static int print_once; |
157 | ||
158 | if (!print_once) { | |
159 | printk(KERN_INFO "CPUFREQ: conservative sampling_rate_max " | |
160 | "sysfs file is deprecated - used by: %s\n", current->comm); | |
161 | print_once = 1; | |
162 | } | |
9acef487 | 163 | return sprintf(buf, "%u\n", MIN_SAMPLING_RATE); |
b9170836 DJ |
164 | } |
165 | ||
18a7247d DJ |
166 | #define define_one_ro(_name) \ |
167 | static struct freq_attr _name = \ | |
b9170836 DJ |
168 | __ATTR(_name, 0444, show_##_name, NULL) |
169 | ||
170 | define_one_ro(sampling_rate_max); | |
171 | define_one_ro(sampling_rate_min); | |
172 | ||
173 | /* cpufreq_conservative Governor Tunables */ | |
174 | #define show_one(file_name, object) \ | |
175 | static ssize_t show_##file_name \ | |
176 | (struct cpufreq_policy *unused, char *buf) \ | |
177 | { \ | |
178 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ | |
179 | } | |
180 | show_one(sampling_rate, sampling_rate); | |
181 | show_one(sampling_down_factor, sampling_down_factor); | |
182 | show_one(up_threshold, up_threshold); | |
183 | show_one(down_threshold, down_threshold); | |
001893cd | 184 | show_one(ignore_nice_load, ignore_nice); |
b9170836 DJ |
185 | show_one(freq_step, freq_step); |
186 | ||
18a7247d | 187 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, |
b9170836 DJ |
188 | const char *buf, size_t count) |
189 | { | |
190 | unsigned int input; | |
191 | int ret; | |
9acef487 | 192 | ret = sscanf(buf, "%u", &input); |
2c906b31 | 193 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
194 | return -EINVAL; |
195 | ||
3fc54d37 | 196 | mutex_lock(&dbs_mutex); |
b9170836 | 197 | dbs_tuners_ins.sampling_down_factor = input; |
3fc54d37 | 198 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
199 | |
200 | return count; | |
201 | } | |
202 | ||
18a7247d | 203 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
b9170836 DJ |
204 | const char *buf, size_t count) |
205 | { | |
206 | unsigned int input; | |
207 | int ret; | |
9acef487 | 208 | ret = sscanf(buf, "%u", &input); |
b9170836 | 209 | |
3fc54d37 | 210 | mutex_lock(&dbs_mutex); |
9acef487 DJ |
211 | if (ret != 1 || input > MAX_SAMPLING_RATE || |
212 | input < MIN_SAMPLING_RATE) { | |
3fc54d37 | 213 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
214 | return -EINVAL; |
215 | } | |
216 | ||
217 | dbs_tuners_ins.sampling_rate = input; | |
3fc54d37 | 218 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
219 | |
220 | return count; | |
221 | } | |
222 | ||
18a7247d | 223 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
b9170836 DJ |
224 | const char *buf, size_t count) |
225 | { | |
226 | unsigned int input; | |
227 | int ret; | |
9acef487 | 228 | ret = sscanf(buf, "%u", &input); |
b9170836 | 229 | |
3fc54d37 | 230 | mutex_lock(&dbs_mutex); |
9acef487 DJ |
231 | if (ret != 1 || input > 100 || |
232 | input <= dbs_tuners_ins.down_threshold) { | |
3fc54d37 | 233 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
234 | return -EINVAL; |
235 | } | |
236 | ||
237 | dbs_tuners_ins.up_threshold = input; | |
3fc54d37 | 238 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
239 | |
240 | return count; | |
241 | } | |
242 | ||
18a7247d | 243 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, |
b9170836 DJ |
244 | const char *buf, size_t count) |
245 | { | |
246 | unsigned int input; | |
247 | int ret; | |
9acef487 | 248 | ret = sscanf(buf, "%u", &input); |
b9170836 | 249 | |
3fc54d37 | 250 | mutex_lock(&dbs_mutex); |
b82fbe6c | 251 | if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) { |
3fc54d37 | 252 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
253 | return -EINVAL; |
254 | } | |
255 | ||
256 | dbs_tuners_ins.down_threshold = input; | |
3fc54d37 | 257 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
258 | |
259 | return count; | |
260 | } | |
261 | ||
001893cd | 262 | static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, |
b9170836 DJ |
263 | const char *buf, size_t count) |
264 | { | |
265 | unsigned int input; | |
266 | int ret; | |
267 | ||
268 | unsigned int j; | |
18a7247d DJ |
269 | |
270 | ret = sscanf(buf, "%u", &input); | |
271 | if (ret != 1) | |
b9170836 DJ |
272 | return -EINVAL; |
273 | ||
18a7247d | 274 | if (input > 1) |
b9170836 | 275 | input = 1; |
18a7247d | 276 | |
3fc54d37 | 277 | mutex_lock(&dbs_mutex); |
18a7247d | 278 | if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */ |
3fc54d37 | 279 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
280 | return count; |
281 | } | |
282 | dbs_tuners_ins.ignore_nice = input; | |
283 | ||
284 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ | |
dac1c1a5 | 285 | for_each_online_cpu(j) { |
b9170836 DJ |
286 | struct cpu_dbs_info_s *j_dbs_info; |
287 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
dac1c1a5 | 288 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j); |
b9170836 DJ |
289 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
290 | } | |
3fc54d37 | 291 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
292 | |
293 | return count; | |
294 | } | |
295 | ||
296 | static ssize_t store_freq_step(struct cpufreq_policy *policy, | |
297 | const char *buf, size_t count) | |
298 | { | |
299 | unsigned int input; | |
300 | int ret; | |
301 | ||
18a7247d | 302 | ret = sscanf(buf, "%u", &input); |
b9170836 | 303 | |
18a7247d | 304 | if (ret != 1) |
b9170836 DJ |
305 | return -EINVAL; |
306 | ||
18a7247d | 307 | if (input > 100) |
b9170836 | 308 | input = 100; |
18a7247d | 309 | |
b9170836 DJ |
310 | /* no need to test here if freq_step is zero as the user might actually |
311 | * want this, they would be crazy though :) */ | |
3fc54d37 | 312 | mutex_lock(&dbs_mutex); |
b9170836 | 313 | dbs_tuners_ins.freq_step = input; |
3fc54d37 | 314 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
315 | |
316 | return count; | |
317 | } | |
318 | ||
319 | #define define_one_rw(_name) \ | |
320 | static struct freq_attr _name = \ | |
321 | __ATTR(_name, 0644, show_##_name, store_##_name) | |
322 | ||
323 | define_one_rw(sampling_rate); | |
324 | define_one_rw(sampling_down_factor); | |
325 | define_one_rw(up_threshold); | |
326 | define_one_rw(down_threshold); | |
001893cd | 327 | define_one_rw(ignore_nice_load); |
b9170836 DJ |
328 | define_one_rw(freq_step); |
329 | ||
9acef487 | 330 | static struct attribute *dbs_attributes[] = { |
b9170836 DJ |
331 | &sampling_rate_max.attr, |
332 | &sampling_rate_min.attr, | |
333 | &sampling_rate.attr, | |
334 | &sampling_down_factor.attr, | |
335 | &up_threshold.attr, | |
336 | &down_threshold.attr, | |
001893cd | 337 | &ignore_nice_load.attr, |
b9170836 DJ |
338 | &freq_step.attr, |
339 | NULL | |
340 | }; | |
341 | ||
342 | static struct attribute_group dbs_attr_group = { | |
343 | .attrs = dbs_attributes, | |
344 | .name = "conservative", | |
345 | }; | |
346 | ||
347 | /************************** sysfs end ************************/ | |
348 | ||
349 | static void dbs_check_cpu(int cpu) | |
350 | { | |
351 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; | |
08a28e2e | 352 | unsigned int tmp_idle_ticks, total_idle_ticks; |
f068c04b | 353 | unsigned int freq_target; |
b9170836 | 354 | unsigned int freq_down_sampling_rate; |
08a28e2e | 355 | struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
b9170836 | 356 | struct cpufreq_policy *policy; |
b9170836 | 357 | |
b9170836 DJ |
358 | if (!this_dbs_info->enable) |
359 | return; | |
360 | ||
08a28e2e AC |
361 | policy = this_dbs_info->cur_policy; |
362 | ||
18a7247d DJ |
363 | /* |
364 | * The default safe range is 20% to 80% | |
b9170836 | 365 | * Every sampling_rate, we check |
18a7247d DJ |
366 | * - If current idle time is less than 20%, then we try to |
367 | * increase frequency | |
b9170836 | 368 | * Every sampling_rate*sampling_down_factor, we check |
18a7247d DJ |
369 | * - If current idle time is more than 80%, then we try to |
370 | * decrease frequency | |
b9170836 | 371 | * |
18a7247d DJ |
372 | * Any frequency increase takes it to the maximum frequency. |
373 | * Frequency reduction happens at minimum steps of | |
374 | * 5% (default) of max_frequency | |
b9170836 DJ |
375 | */ |
376 | ||
377 | /* Check for frequency increase */ | |
9c7d269b | 378 | idle_ticks = UINT_MAX; |
b9170836 | 379 | |
08a28e2e AC |
380 | /* Check for frequency increase */ |
381 | total_idle_ticks = get_cpu_idle_time(cpu); | |
382 | tmp_idle_ticks = total_idle_ticks - | |
383 | this_dbs_info->prev_cpu_idle_up; | |
384 | this_dbs_info->prev_cpu_idle_up = total_idle_ticks; | |
385 | ||
386 | if (tmp_idle_ticks < idle_ticks) | |
387 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
388 | |
389 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
390 | idle_ticks *= 100; | |
391 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * | |
2c906b31 | 392 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
b9170836 DJ |
393 | |
394 | if (idle_ticks < up_idle_ticks) { | |
a159b827 | 395 | this_dbs_info->down_skip = 0; |
08a28e2e AC |
396 | this_dbs_info->prev_cpu_idle_down = |
397 | this_dbs_info->prev_cpu_idle_up; | |
790d76fa | 398 | |
b9170836 | 399 | /* if we are already at full speed then break out early */ |
a159b827 | 400 | if (this_dbs_info->requested_freq == policy->max) |
b9170836 | 401 | return; |
18a7247d | 402 | |
f068c04b | 403 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
b9170836 DJ |
404 | |
405 | /* max freq cannot be less than 100. But who knows.... */ | |
f068c04b DJ |
406 | if (unlikely(freq_target == 0)) |
407 | freq_target = 5; | |
18a7247d | 408 | |
f068c04b | 409 | this_dbs_info->requested_freq += freq_target; |
a159b827 AC |
410 | if (this_dbs_info->requested_freq > policy->max) |
411 | this_dbs_info->requested_freq = policy->max; | |
b9170836 | 412 | |
a159b827 | 413 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
b9170836 | 414 | CPUFREQ_RELATION_H); |
b9170836 DJ |
415 | return; |
416 | } | |
417 | ||
418 | /* Check for frequency decrease */ | |
a159b827 AC |
419 | this_dbs_info->down_skip++; |
420 | if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor) | |
b9170836 DJ |
421 | return; |
422 | ||
08a28e2e AC |
423 | /* Check for frequency decrease */ |
424 | total_idle_ticks = this_dbs_info->prev_cpu_idle_up; | |
425 | tmp_idle_ticks = total_idle_ticks - | |
426 | this_dbs_info->prev_cpu_idle_down; | |
427 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; | |
b9170836 | 428 | |
08a28e2e AC |
429 | if (tmp_idle_ticks < idle_ticks) |
430 | idle_ticks = tmp_idle_ticks; | |
b9170836 DJ |
431 | |
432 | /* Scale idle ticks by 100 and compare with up and down ticks */ | |
433 | idle_ticks *= 100; | |
a159b827 | 434 | this_dbs_info->down_skip = 0; |
b9170836 DJ |
435 | |
436 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * | |
437 | dbs_tuners_ins.sampling_down_factor; | |
438 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * | |
2c906b31 | 439 | usecs_to_jiffies(freq_down_sampling_rate); |
b9170836 | 440 | |
9c7d269b | 441 | if (idle_ticks > down_idle_ticks) { |
2c906b31 AC |
442 | /* |
443 | * if we are already at the lowest speed then break out early | |
b9170836 | 444 | * or if we 'cannot' reduce the speed as the user might want |
f068c04b | 445 | * freq_target to be zero |
2c906b31 | 446 | */ |
a159b827 | 447 | if (this_dbs_info->requested_freq == policy->min |
b9170836 DJ |
448 | || dbs_tuners_ins.freq_step == 0) |
449 | return; | |
450 | ||
f068c04b | 451 | freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100; |
b9170836 DJ |
452 | |
453 | /* max freq cannot be less than 100. But who knows.... */ | |
f068c04b DJ |
454 | if (unlikely(freq_target == 0)) |
455 | freq_target = 5; | |
b9170836 | 456 | |
f068c04b | 457 | this_dbs_info->requested_freq -= freq_target; |
a159b827 AC |
458 | if (this_dbs_info->requested_freq < policy->min) |
459 | this_dbs_info->requested_freq = policy->min; | |
b9170836 | 460 | |
a159b827 | 461 | __cpufreq_driver_target(policy, this_dbs_info->requested_freq, |
2c906b31 | 462 | CPUFREQ_RELATION_H); |
b9170836 DJ |
463 | return; |
464 | } | |
465 | } | |
466 | ||
c4028958 | 467 | static void do_dbs_timer(struct work_struct *work) |
18a7247d | 468 | { |
b9170836 | 469 | int i; |
3fc54d37 | 470 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
471 | for_each_online_cpu(i) |
472 | dbs_check_cpu(i); | |
18a7247d | 473 | schedule_delayed_work(&dbs_work, |
b9170836 | 474 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
3fc54d37 | 475 | mutex_unlock(&dbs_mutex); |
18a7247d | 476 | } |
b9170836 DJ |
477 | |
478 | static inline void dbs_timer_init(void) | |
479 | { | |
8217e4f4 | 480 | init_timer_deferrable(&dbs_work.timer); |
b9170836 DJ |
481 | schedule_delayed_work(&dbs_work, |
482 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); | |
483 | return; | |
484 | } | |
485 | ||
486 | static inline void dbs_timer_exit(void) | |
487 | { | |
488 | cancel_delayed_work(&dbs_work); | |
489 | return; | |
490 | } | |
491 | ||
492 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, | |
493 | unsigned int event) | |
494 | { | |
495 | unsigned int cpu = policy->cpu; | |
496 | struct cpu_dbs_info_s *this_dbs_info; | |
497 | unsigned int j; | |
914f7c31 | 498 | int rc; |
b9170836 DJ |
499 | |
500 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
501 | ||
502 | switch (event) { | |
503 | case CPUFREQ_GOV_START: | |
18a7247d | 504 | if ((!cpu_online(cpu)) || (!policy->cur)) |
b9170836 DJ |
505 | return -EINVAL; |
506 | ||
b9170836 DJ |
507 | if (this_dbs_info->enable) /* Already enabled */ |
508 | break; | |
18a7247d | 509 | |
3fc54d37 | 510 | mutex_lock(&dbs_mutex); |
914f7c31 JG |
511 | |
512 | rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); | |
513 | if (rc) { | |
514 | mutex_unlock(&dbs_mutex); | |
515 | return rc; | |
516 | } | |
517 | ||
835481d9 | 518 | for_each_cpu(j, policy->cpus) { |
b9170836 DJ |
519 | struct cpu_dbs_info_s *j_dbs_info; |
520 | j_dbs_info = &per_cpu(cpu_dbs_info, j); | |
521 | j_dbs_info->cur_policy = policy; | |
18a7247d | 522 | |
08a28e2e | 523 | j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(cpu); |
b9170836 DJ |
524 | j_dbs_info->prev_cpu_idle_down |
525 | = j_dbs_info->prev_cpu_idle_up; | |
526 | } | |
527 | this_dbs_info->enable = 1; | |
a159b827 AC |
528 | this_dbs_info->down_skip = 0; |
529 | this_dbs_info->requested_freq = policy->cur; | |
914f7c31 | 530 | |
b9170836 DJ |
531 | dbs_enable++; |
532 | /* | |
533 | * Start the timerschedule work, when this governor | |
534 | * is used for first time | |
535 | */ | |
536 | if (dbs_enable == 1) { | |
537 | unsigned int latency; | |
538 | /* policy latency is in nS. Convert it to uS first */ | |
2c906b31 AC |
539 | latency = policy->cpuinfo.transition_latency / 1000; |
540 | if (latency == 0) | |
541 | latency = 1; | |
b9170836 | 542 | |
e8a02572 | 543 | def_sampling_rate = 10 * latency * |
b9170836 | 544 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
2c906b31 AC |
545 | |
546 | if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) | |
547 | def_sampling_rate = MIN_STAT_SAMPLING_RATE; | |
548 | ||
b9170836 | 549 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
b9170836 DJ |
550 | |
551 | dbs_timer_init(); | |
a8d7c3bc EO |
552 | cpufreq_register_notifier( |
553 | &dbs_cpufreq_notifier_block, | |
554 | CPUFREQ_TRANSITION_NOTIFIER); | |
b9170836 | 555 | } |
18a7247d | 556 | |
3fc54d37 | 557 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
558 | break; |
559 | ||
560 | case CPUFREQ_GOV_STOP: | |
3fc54d37 | 561 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
562 | this_dbs_info->enable = 0; |
563 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); | |
564 | dbs_enable--; | |
565 | /* | |
566 | * Stop the timerschedule work, when this governor | |
567 | * is used for first time | |
568 | */ | |
a8d7c3bc | 569 | if (dbs_enable == 0) { |
b9170836 | 570 | dbs_timer_exit(); |
a8d7c3bc EO |
571 | cpufreq_unregister_notifier( |
572 | &dbs_cpufreq_notifier_block, | |
573 | CPUFREQ_TRANSITION_NOTIFIER); | |
574 | } | |
575 | ||
3fc54d37 | 576 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
577 | |
578 | break; | |
579 | ||
580 | case CPUFREQ_GOV_LIMITS: | |
3fc54d37 | 581 | mutex_lock(&dbs_mutex); |
b9170836 DJ |
582 | if (policy->max < this_dbs_info->cur_policy->cur) |
583 | __cpufreq_driver_target( | |
584 | this_dbs_info->cur_policy, | |
18a7247d | 585 | policy->max, CPUFREQ_RELATION_H); |
b9170836 DJ |
586 | else if (policy->min > this_dbs_info->cur_policy->cur) |
587 | __cpufreq_driver_target( | |
588 | this_dbs_info->cur_policy, | |
18a7247d | 589 | policy->min, CPUFREQ_RELATION_L); |
3fc54d37 | 590 | mutex_unlock(&dbs_mutex); |
b9170836 DJ |
591 | break; |
592 | } | |
593 | return 0; | |
594 | } | |
595 | ||
c4d14bc0 SW |
596 | #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
597 | static | |
598 | #endif | |
1c256245 TR |
599 | struct cpufreq_governor cpufreq_gov_conservative = { |
600 | .name = "conservative", | |
601 | .governor = cpufreq_governor_dbs, | |
602 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, | |
603 | .owner = THIS_MODULE, | |
b9170836 DJ |
604 | }; |
605 | ||
606 | static int __init cpufreq_gov_dbs_init(void) | |
607 | { | |
1c256245 | 608 | return cpufreq_register_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
609 | } |
610 | ||
611 | static void __exit cpufreq_gov_dbs_exit(void) | |
612 | { | |
613 | /* Make sure that the scheduled work is indeed not running */ | |
614 | flush_scheduled_work(); | |
615 | ||
1c256245 | 616 | cpufreq_unregister_governor(&cpufreq_gov_conservative); |
b9170836 DJ |
617 | } |
618 | ||
619 | ||
9acef487 DJ |
620 | MODULE_AUTHOR("Alexander Clouter <alex-kernel@digriz.org.uk>"); |
621 | MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " | |
b9170836 DJ |
622 | "Low Latency Frequency Transition capable processors " |
623 | "optimised for use in a battery environment"); | |
9acef487 | 624 | MODULE_LICENSE("GPL"); |
b9170836 | 625 | |
6915719b JW |
626 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
627 | fs_initcall(cpufreq_gov_dbs_init); | |
628 | #else | |
b9170836 | 629 | module_init(cpufreq_gov_dbs_init); |
6915719b | 630 | #endif |
b9170836 | 631 | module_exit(cpufreq_gov_dbs_exit); |