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> | |
11a80a9c | 7 | * (C) 2009 Alexander Clouter <alex@digriz.org.uk> |
b9170836 DJ |
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 | ||
4d5dcc42 | 14 | #include <linux/slab.h> |
4471a34f | 15 | #include "cpufreq_governor.h" |
b9170836 | 16 | |
7d5a9956 RW |
17 | struct cs_policy_dbs_info { |
18 | struct policy_dbs_info policy_dbs; | |
19 | unsigned int down_skip; | |
20 | unsigned int requested_freq; | |
21 | }; | |
22 | ||
23 | static inline struct cs_policy_dbs_info *to_dbs_info(struct policy_dbs_info *policy_dbs) | |
24 | { | |
25 | return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs); | |
26 | } | |
27 | ||
47ebaac1 RW |
28 | struct cs_dbs_tuners { |
29 | unsigned int down_threshold; | |
30 | unsigned int freq_step; | |
31 | }; | |
32 | ||
c88883cd | 33 | /* Conservative governor macros */ |
b9170836 | 34 | #define DEF_FREQUENCY_UP_THRESHOLD (80) |
b9170836 | 35 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
98765847 | 36 | #define DEF_FREQUENCY_STEP (5) |
2c906b31 AC |
37 | #define DEF_SAMPLING_DOWN_FACTOR (1) |
38 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
b9170836 | 39 | |
98765847 SK |
40 | static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners, |
41 | struct cpufreq_policy *policy) | |
42 | { | |
43 | unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100; | |
44 | ||
45 | /* max freq cannot be less than 100. But who knows... */ | |
46 | if (unlikely(freq_target == 0)) | |
47 | freq_target = DEF_FREQUENCY_STEP; | |
48 | ||
49 | return freq_target; | |
50 | } | |
51 | ||
4471a34f VK |
52 | /* |
53 | * Every sampling_rate, we check, if current idle time is less than 20% | |
7af1c056 SK |
54 | * (default), then we try to increase frequency. Every sampling_rate * |
55 | * sampling_down_factor, we check, if current idle time is more than 80% | |
56 | * (default), then we try to decrease frequency | |
4471a34f VK |
57 | * |
58 | * Any frequency increase takes it to the maximum frequency. Frequency reduction | |
59 | * happens at minimum steps of 5% (default) of maximum frequency | |
60 | */ | |
4cccf755 | 61 | static unsigned int cs_dbs_timer(struct cpufreq_policy *policy) |
a8d7c3bc | 62 | { |
bc505475 | 63 | struct policy_dbs_info *policy_dbs = policy->governor_data; |
7d5a9956 | 64 | struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs); |
bc505475 | 65 | struct dbs_data *dbs_data = policy_dbs->dbs_data; |
4d5dcc42 | 66 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
4cccf755 | 67 | unsigned int load = dbs_update(policy); |
4471a34f VK |
68 | |
69 | /* | |
70 | * break out if we 'cannot' reduce the speed as the user might | |
71 | * want freq_step to be zero | |
72 | */ | |
4d5dcc42 | 73 | if (cs_tuners->freq_step == 0) |
4cccf755 | 74 | goto out; |
4471a34f VK |
75 | |
76 | /* Check for frequency increase */ | |
ff4b1789 | 77 | if (load > dbs_data->up_threshold) { |
4471a34f VK |
78 | dbs_info->down_skip = 0; |
79 | ||
80 | /* if we are already at full speed then break out early */ | |
81 | if (dbs_info->requested_freq == policy->max) | |
4cccf755 | 82 | goto out; |
4471a34f | 83 | |
98765847 | 84 | dbs_info->requested_freq += get_freq_target(cs_tuners, policy); |
a8d7c3bc | 85 | |
6d7bcb14 XC |
86 | if (dbs_info->requested_freq > policy->max) |
87 | dbs_info->requested_freq = policy->max; | |
88 | ||
4471a34f VK |
89 | __cpufreq_driver_target(policy, dbs_info->requested_freq, |
90 | CPUFREQ_RELATION_H); | |
4cccf755 | 91 | goto out; |
4471a34f VK |
92 | } |
93 | ||
7af1c056 | 94 | /* if sampling_down_factor is active break out early */ |
ff4b1789 | 95 | if (++dbs_info->down_skip < dbs_data->sampling_down_factor) |
4cccf755 | 96 | goto out; |
7af1c056 SK |
97 | dbs_info->down_skip = 0; |
98 | ||
27ed3cd2 SK |
99 | /* Check for frequency decrease */ |
100 | if (load < cs_tuners->down_threshold) { | |
3baa976a | 101 | unsigned int freq_target; |
4471a34f VK |
102 | /* |
103 | * if we cannot reduce the frequency anymore, break out early | |
104 | */ | |
105 | if (policy->cur == policy->min) | |
4cccf755 | 106 | goto out; |
4471a34f | 107 | |
3baa976a XC |
108 | freq_target = get_freq_target(cs_tuners, policy); |
109 | if (dbs_info->requested_freq > freq_target) | |
110 | dbs_info->requested_freq -= freq_target; | |
111 | else | |
112 | dbs_info->requested_freq = policy->min; | |
ad529a9c | 113 | |
4471a34f | 114 | __cpufreq_driver_target(policy, dbs_info->requested_freq, |
fed573d5 | 115 | CPUFREQ_RELATION_L); |
4471a34f | 116 | } |
43e0ee36 | 117 | |
4cccf755 | 118 | out: |
07aa4402 | 119 | return dbs_data->sampling_rate; |
66df2a01 FB |
120 | } |
121 | ||
4471a34f | 122 | static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, |
af926185 | 123 | void *data); |
a8d7c3bc | 124 | |
8e0484d2 VK |
125 | static struct notifier_block cs_cpufreq_notifier_block = { |
126 | .notifier_call = dbs_cpufreq_notifier, | |
127 | }; | |
128 | ||
b9170836 | 129 | /************************** sysfs interface ************************/ |
7bdad34d | 130 | static struct dbs_governor cs_dbs_gov; |
b9170836 | 131 | |
4d5dcc42 VK |
132 | static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data, |
133 | const char *buf, size_t count) | |
b9170836 DJ |
134 | { |
135 | unsigned int input; | |
136 | int ret; | |
9acef487 | 137 | ret = sscanf(buf, "%u", &input); |
8e677ce8 | 138 | |
2c906b31 | 139 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
140 | return -EINVAL; |
141 | ||
ff4b1789 | 142 | dbs_data->sampling_down_factor = input; |
b9170836 DJ |
143 | return count; |
144 | } | |
145 | ||
4d5dcc42 VK |
146 | static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf, |
147 | size_t count) | |
b9170836 | 148 | { |
4d5dcc42 | 149 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
150 | unsigned int input; |
151 | int ret; | |
9acef487 | 152 | ret = sscanf(buf, "%u", &input); |
b9170836 | 153 | |
4d5dcc42 | 154 | if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold) |
b9170836 | 155 | return -EINVAL; |
b9170836 | 156 | |
ff4b1789 | 157 | dbs_data->up_threshold = input; |
b9170836 DJ |
158 | return count; |
159 | } | |
160 | ||
4d5dcc42 VK |
161 | static ssize_t store_down_threshold(struct dbs_data *dbs_data, const char *buf, |
162 | size_t count) | |
b9170836 | 163 | { |
4d5dcc42 | 164 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
165 | unsigned int input; |
166 | int ret; | |
9acef487 | 167 | ret = sscanf(buf, "%u", &input); |
b9170836 | 168 | |
8e677ce8 AC |
169 | /* cannot be lower than 11 otherwise freq will not fall */ |
170 | if (ret != 1 || input < 11 || input > 100 || | |
ff4b1789 | 171 | input >= dbs_data->up_threshold) |
b9170836 | 172 | return -EINVAL; |
b9170836 | 173 | |
4d5dcc42 | 174 | cs_tuners->down_threshold = input; |
b9170836 DJ |
175 | return count; |
176 | } | |
177 | ||
6c4640c3 VK |
178 | static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data, |
179 | const char *buf, size_t count) | |
b9170836 | 180 | { |
a33cce1c | 181 | unsigned int input; |
b9170836 DJ |
182 | int ret; |
183 | ||
18a7247d DJ |
184 | ret = sscanf(buf, "%u", &input); |
185 | if (ret != 1) | |
b9170836 DJ |
186 | return -EINVAL; |
187 | ||
18a7247d | 188 | if (input > 1) |
b9170836 | 189 | input = 1; |
18a7247d | 190 | |
ff4b1789 | 191 | if (input == dbs_data->ignore_nice_load) /* nothing to do */ |
b9170836 | 192 | return count; |
326c86de | 193 | |
ff4b1789 | 194 | dbs_data->ignore_nice_load = input; |
b9170836 | 195 | |
8e677ce8 | 196 | /* we need to re-evaluate prev_cpu_idle */ |
8c8f77fd | 197 | gov_update_cpu_data(dbs_data); |
a33cce1c | 198 | |
b9170836 DJ |
199 | return count; |
200 | } | |
201 | ||
4d5dcc42 VK |
202 | static ssize_t store_freq_step(struct dbs_data *dbs_data, const char *buf, |
203 | size_t count) | |
b9170836 | 204 | { |
4d5dcc42 | 205 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
206 | unsigned int input; |
207 | int ret; | |
18a7247d | 208 | ret = sscanf(buf, "%u", &input); |
b9170836 | 209 | |
18a7247d | 210 | if (ret != 1) |
b9170836 DJ |
211 | return -EINVAL; |
212 | ||
18a7247d | 213 | if (input > 100) |
b9170836 | 214 | input = 100; |
18a7247d | 215 | |
4471a34f VK |
216 | /* |
217 | * no need to test here if freq_step is zero as the user might actually | |
218 | * want this, they would be crazy though :) | |
219 | */ | |
4d5dcc42 | 220 | cs_tuners->freq_step = input; |
b9170836 DJ |
221 | return count; |
222 | } | |
223 | ||
c4435630 VK |
224 | gov_show_one_common(sampling_rate); |
225 | gov_show_one_common(sampling_down_factor); | |
226 | gov_show_one_common(up_threshold); | |
227 | gov_show_one_common(ignore_nice_load); | |
228 | gov_show_one_common(min_sampling_rate); | |
229 | gov_show_one(cs, down_threshold); | |
230 | gov_show_one(cs, freq_step); | |
231 | ||
232 | gov_attr_rw(sampling_rate); | |
233 | gov_attr_rw(sampling_down_factor); | |
234 | gov_attr_rw(up_threshold); | |
235 | gov_attr_rw(ignore_nice_load); | |
236 | gov_attr_ro(min_sampling_rate); | |
237 | gov_attr_rw(down_threshold); | |
238 | gov_attr_rw(freq_step); | |
239 | ||
240 | static struct attribute *cs_attributes[] = { | |
241 | &min_sampling_rate.attr, | |
242 | &sampling_rate.attr, | |
243 | &sampling_down_factor.attr, | |
244 | &up_threshold.attr, | |
245 | &down_threshold.attr, | |
246 | &ignore_nice_load.attr, | |
247 | &freq_step.attr, | |
b9170836 DJ |
248 | NULL |
249 | }; | |
250 | ||
b9170836 DJ |
251 | /************************** sysfs end ************************/ |
252 | ||
7d5a9956 RW |
253 | static struct policy_dbs_info *cs_alloc(void) |
254 | { | |
255 | struct cs_policy_dbs_info *dbs_info; | |
256 | ||
257 | dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL); | |
258 | return dbs_info ? &dbs_info->policy_dbs : NULL; | |
259 | } | |
260 | ||
261 | static void cs_free(struct policy_dbs_info *policy_dbs) | |
262 | { | |
263 | kfree(to_dbs_info(policy_dbs)); | |
264 | } | |
265 | ||
8e0484d2 | 266 | static int cs_init(struct dbs_data *dbs_data, bool notify) |
4d5dcc42 VK |
267 | { |
268 | struct cs_dbs_tuners *tuners; | |
269 | ||
d5b73cd8 | 270 | tuners = kzalloc(sizeof(*tuners), GFP_KERNEL); |
4d5dcc42 VK |
271 | if (!tuners) { |
272 | pr_err("%s: kzalloc failed\n", __func__); | |
273 | return -ENOMEM; | |
274 | } | |
275 | ||
4d5dcc42 | 276 | tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; |
98765847 | 277 | tuners->freq_step = DEF_FREQUENCY_STEP; |
ff4b1789 VK |
278 | dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; |
279 | dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; | |
280 | dbs_data->ignore_nice_load = 0; | |
4d5dcc42 VK |
281 | |
282 | dbs_data->tuners = tuners; | |
283 | dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO * | |
284 | jiffies_to_usecs(10); | |
8e0484d2 VK |
285 | |
286 | if (notify) | |
287 | cpufreq_register_notifier(&cs_cpufreq_notifier_block, | |
288 | CPUFREQ_TRANSITION_NOTIFIER); | |
289 | ||
4d5dcc42 VK |
290 | return 0; |
291 | } | |
292 | ||
8e0484d2 | 293 | static void cs_exit(struct dbs_data *dbs_data, bool notify) |
4d5dcc42 | 294 | { |
8e0484d2 VK |
295 | if (notify) |
296 | cpufreq_unregister_notifier(&cs_cpufreq_notifier_block, | |
297 | CPUFREQ_TRANSITION_NOTIFIER); | |
298 | ||
4d5dcc42 VK |
299 | kfree(dbs_data->tuners); |
300 | } | |
301 | ||
702c9e54 RW |
302 | static void cs_start(struct cpufreq_policy *policy) |
303 | { | |
7d5a9956 | 304 | struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data); |
702c9e54 RW |
305 | |
306 | dbs_info->down_skip = 0; | |
307 | dbs_info->requested_freq = policy->cur; | |
308 | } | |
309 | ||
7bdad34d | 310 | static struct dbs_governor cs_dbs_gov = { |
af926185 RW |
311 | .gov = { |
312 | .name = "conservative", | |
906a6e5a | 313 | .governor = cpufreq_governor_dbs, |
af926185 RW |
314 | .max_transition_latency = TRANSITION_LATENCY_LIMIT, |
315 | .owner = THIS_MODULE, | |
316 | }, | |
c4435630 | 317 | .kobj_type = { .default_attrs = cs_attributes }, |
4471a34f | 318 | .gov_dbs_timer = cs_dbs_timer, |
7d5a9956 RW |
319 | .alloc = cs_alloc, |
320 | .free = cs_free, | |
4d5dcc42 VK |
321 | .init = cs_init, |
322 | .exit = cs_exit, | |
702c9e54 | 323 | .start = cs_start, |
4471a34f | 324 | }; |
b9170836 | 325 | |
7bdad34d | 326 | #define CPU_FREQ_GOV_CONSERVATIVE (&cs_dbs_gov.gov) |
af926185 | 327 | |
af926185 RW |
328 | static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, |
329 | void *data) | |
330 | { | |
331 | struct cpufreq_freqs *freq = data; | |
af926185 | 332 | struct cpufreq_policy *policy = cpufreq_cpu_get_raw(freq->cpu); |
7d5a9956 | 333 | struct cs_policy_dbs_info *dbs_info; |
af926185 RW |
334 | |
335 | if (!policy) | |
336 | return 0; | |
337 | ||
338 | /* policy isn't governed by conservative governor */ | |
339 | if (policy->governor != CPU_FREQ_GOV_CONSERVATIVE) | |
340 | return 0; | |
341 | ||
7d5a9956 | 342 | dbs_info = to_dbs_info(policy->governor_data); |
af926185 RW |
343 | /* |
344 | * we only care if our internally tracked freq moves outside the 'valid' | |
345 | * ranges of frequency available to us otherwise we do not change it | |
346 | */ | |
347 | if (dbs_info->requested_freq > policy->max | |
348 | || dbs_info->requested_freq < policy->min) | |
349 | dbs_info->requested_freq = freq->new; | |
350 | ||
351 | return 0; | |
352 | } | |
353 | ||
b9170836 DJ |
354 | static int __init cpufreq_gov_dbs_init(void) |
355 | { | |
af926185 | 356 | return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
357 | } |
358 | ||
359 | static void __exit cpufreq_gov_dbs_exit(void) | |
360 | { | |
af926185 | 361 | cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
362 | } |
363 | ||
11a80a9c | 364 | MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); |
9acef487 | 365 | MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
b9170836 DJ |
366 | "Low Latency Frequency Transition capable processors " |
367 | "optimised for use in a battery environment"); | |
9acef487 | 368 | MODULE_LICENSE("GPL"); |
b9170836 | 369 | |
6915719b | 370 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
de1df26b RW |
371 | struct cpufreq_governor *cpufreq_default_governor(void) |
372 | { | |
af926185 | 373 | return CPU_FREQ_GOV_CONSERVATIVE; |
de1df26b RW |
374 | } |
375 | ||
6915719b JW |
376 | fs_initcall(cpufreq_gov_dbs_init); |
377 | #else | |
b9170836 | 378 | module_init(cpufreq_gov_dbs_init); |
6915719b | 379 | #endif |
b9170836 | 380 | module_exit(cpufreq_gov_dbs_exit); |