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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; | |
abb66279 | 20 | unsigned int requested_freq; |
7d5a9956 RW |
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 | */ | |
26f0dbc9 | 61 | static unsigned int cs_dbs_update(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); |
abb66279 | 65 | unsigned int requested_freq = dbs_info->requested_freq; |
bc505475 | 66 | struct dbs_data *dbs_data = policy_dbs->dbs_data; |
4d5dcc42 | 67 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
4cccf755 | 68 | unsigned int load = dbs_update(policy); |
4471a34f VK |
69 | |
70 | /* | |
71 | * break out if we 'cannot' reduce the speed as the user might | |
72 | * want freq_step to be zero | |
73 | */ | |
4d5dcc42 | 74 | if (cs_tuners->freq_step == 0) |
4cccf755 | 75 | goto out; |
4471a34f | 76 | |
abb66279 RW |
77 | /* |
78 | * If requested_freq is out of range, it is likely that the limits | |
79 | * changed in the meantime, so fall back to current frequency in that | |
80 | * case. | |
81 | */ | |
82 | if (requested_freq > policy->max || requested_freq < policy->min) | |
83 | requested_freq = policy->cur; | |
84 | ||
4471a34f | 85 | /* Check for frequency increase */ |
ff4b1789 | 86 | if (load > dbs_data->up_threshold) { |
4471a34f VK |
87 | dbs_info->down_skip = 0; |
88 | ||
89 | /* if we are already at full speed then break out early */ | |
d352cf47 | 90 | if (requested_freq == policy->max) |
4cccf755 | 91 | goto out; |
4471a34f | 92 | |
d352cf47 | 93 | requested_freq += get_freq_target(cs_tuners, policy); |
abb66279 RW |
94 | if (requested_freq > policy->max) |
95 | requested_freq = policy->max; | |
6d7bcb14 | 96 | |
d352cf47 | 97 | __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_H); |
abb66279 | 98 | dbs_info->requested_freq = requested_freq; |
4cccf755 | 99 | goto out; |
4471a34f VK |
100 | } |
101 | ||
7af1c056 | 102 | /* if sampling_down_factor is active break out early */ |
ff4b1789 | 103 | if (++dbs_info->down_skip < dbs_data->sampling_down_factor) |
4cccf755 | 104 | goto out; |
7af1c056 SK |
105 | dbs_info->down_skip = 0; |
106 | ||
27ed3cd2 SK |
107 | /* Check for frequency decrease */ |
108 | if (load < cs_tuners->down_threshold) { | |
abb66279 | 109 | unsigned int freq_target; |
4471a34f VK |
110 | /* |
111 | * if we cannot reduce the frequency anymore, break out early | |
112 | */ | |
d352cf47 | 113 | if (requested_freq == policy->min) |
4cccf755 | 114 | goto out; |
4471a34f | 115 | |
3baa976a | 116 | freq_target = get_freq_target(cs_tuners, policy); |
d352cf47 RW |
117 | if (requested_freq > freq_target) |
118 | requested_freq -= freq_target; | |
3baa976a | 119 | else |
d352cf47 | 120 | requested_freq = policy->min; |
ad529a9c | 121 | |
d352cf47 | 122 | __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_L); |
abb66279 | 123 | dbs_info->requested_freq = requested_freq; |
4471a34f | 124 | } |
43e0ee36 | 125 | |
4cccf755 | 126 | out: |
07aa4402 | 127 | return dbs_data->sampling_rate; |
66df2a01 FB |
128 | } |
129 | ||
b9170836 | 130 | /************************** sysfs interface ************************/ |
b9170836 | 131 | |
0dd3c1d6 RW |
132 | static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set, |
133 | const char *buf, size_t count) | |
b9170836 | 134 | { |
0dd3c1d6 | 135 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
b9170836 DJ |
136 | unsigned int input; |
137 | int ret; | |
9acef487 | 138 | ret = sscanf(buf, "%u", &input); |
8e677ce8 | 139 | |
2c906b31 | 140 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
141 | return -EINVAL; |
142 | ||
ff4b1789 | 143 | dbs_data->sampling_down_factor = input; |
b9170836 DJ |
144 | return count; |
145 | } | |
146 | ||
0dd3c1d6 RW |
147 | static ssize_t store_up_threshold(struct gov_attr_set *attr_set, |
148 | const char *buf, size_t count) | |
b9170836 | 149 | { |
0dd3c1d6 | 150 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
4d5dcc42 | 151 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
152 | unsigned int input; |
153 | int ret; | |
9acef487 | 154 | ret = sscanf(buf, "%u", &input); |
b9170836 | 155 | |
4d5dcc42 | 156 | if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold) |
b9170836 | 157 | return -EINVAL; |
b9170836 | 158 | |
ff4b1789 | 159 | dbs_data->up_threshold = input; |
b9170836 DJ |
160 | return count; |
161 | } | |
162 | ||
0dd3c1d6 RW |
163 | static ssize_t store_down_threshold(struct gov_attr_set *attr_set, |
164 | const char *buf, size_t count) | |
b9170836 | 165 | { |
0dd3c1d6 | 166 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
4d5dcc42 | 167 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
168 | unsigned int input; |
169 | int ret; | |
9acef487 | 170 | ret = sscanf(buf, "%u", &input); |
b9170836 | 171 | |
8e677ce8 AC |
172 | /* cannot be lower than 11 otherwise freq will not fall */ |
173 | if (ret != 1 || input < 11 || input > 100 || | |
ff4b1789 | 174 | input >= dbs_data->up_threshold) |
b9170836 | 175 | return -EINVAL; |
b9170836 | 176 | |
4d5dcc42 | 177 | cs_tuners->down_threshold = input; |
b9170836 DJ |
178 | return count; |
179 | } | |
180 | ||
0dd3c1d6 RW |
181 | static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set, |
182 | const char *buf, size_t count) | |
b9170836 | 183 | { |
0dd3c1d6 | 184 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
a33cce1c | 185 | unsigned int input; |
b9170836 DJ |
186 | int ret; |
187 | ||
18a7247d DJ |
188 | ret = sscanf(buf, "%u", &input); |
189 | if (ret != 1) | |
b9170836 DJ |
190 | return -EINVAL; |
191 | ||
18a7247d | 192 | if (input > 1) |
b9170836 | 193 | input = 1; |
18a7247d | 194 | |
ff4b1789 | 195 | if (input == dbs_data->ignore_nice_load) /* nothing to do */ |
b9170836 | 196 | return count; |
326c86de | 197 | |
ff4b1789 | 198 | dbs_data->ignore_nice_load = input; |
b9170836 | 199 | |
8e677ce8 | 200 | /* we need to re-evaluate prev_cpu_idle */ |
8c8f77fd | 201 | gov_update_cpu_data(dbs_data); |
a33cce1c | 202 | |
b9170836 DJ |
203 | return count; |
204 | } | |
205 | ||
0dd3c1d6 RW |
206 | static ssize_t store_freq_step(struct gov_attr_set *attr_set, const char *buf, |
207 | size_t count) | |
b9170836 | 208 | { |
0dd3c1d6 | 209 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
4d5dcc42 | 210 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
211 | unsigned int input; |
212 | int ret; | |
18a7247d | 213 | ret = sscanf(buf, "%u", &input); |
b9170836 | 214 | |
18a7247d | 215 | if (ret != 1) |
b9170836 DJ |
216 | return -EINVAL; |
217 | ||
18a7247d | 218 | if (input > 100) |
b9170836 | 219 | input = 100; |
18a7247d | 220 | |
4471a34f VK |
221 | /* |
222 | * no need to test here if freq_step is zero as the user might actually | |
223 | * want this, they would be crazy though :) | |
224 | */ | |
4d5dcc42 | 225 | cs_tuners->freq_step = input; |
b9170836 DJ |
226 | return count; |
227 | } | |
228 | ||
c4435630 VK |
229 | gov_show_one_common(sampling_rate); |
230 | gov_show_one_common(sampling_down_factor); | |
231 | gov_show_one_common(up_threshold); | |
232 | gov_show_one_common(ignore_nice_load); | |
233 | gov_show_one_common(min_sampling_rate); | |
234 | gov_show_one(cs, down_threshold); | |
235 | gov_show_one(cs, freq_step); | |
236 | ||
237 | gov_attr_rw(sampling_rate); | |
238 | gov_attr_rw(sampling_down_factor); | |
239 | gov_attr_rw(up_threshold); | |
240 | gov_attr_rw(ignore_nice_load); | |
241 | gov_attr_ro(min_sampling_rate); | |
242 | gov_attr_rw(down_threshold); | |
243 | gov_attr_rw(freq_step); | |
244 | ||
245 | static struct attribute *cs_attributes[] = { | |
246 | &min_sampling_rate.attr, | |
247 | &sampling_rate.attr, | |
248 | &sampling_down_factor.attr, | |
249 | &up_threshold.attr, | |
250 | &down_threshold.attr, | |
251 | &ignore_nice_load.attr, | |
252 | &freq_step.attr, | |
b9170836 DJ |
253 | NULL |
254 | }; | |
255 | ||
b9170836 DJ |
256 | /************************** sysfs end ************************/ |
257 | ||
7d5a9956 RW |
258 | static struct policy_dbs_info *cs_alloc(void) |
259 | { | |
260 | struct cs_policy_dbs_info *dbs_info; | |
261 | ||
262 | dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL); | |
263 | return dbs_info ? &dbs_info->policy_dbs : NULL; | |
264 | } | |
265 | ||
266 | static void cs_free(struct policy_dbs_info *policy_dbs) | |
267 | { | |
268 | kfree(to_dbs_info(policy_dbs)); | |
269 | } | |
270 | ||
9a15fb2c | 271 | static int cs_init(struct dbs_data *dbs_data) |
4d5dcc42 VK |
272 | { |
273 | struct cs_dbs_tuners *tuners; | |
274 | ||
d5b73cd8 | 275 | tuners = kzalloc(sizeof(*tuners), GFP_KERNEL); |
a69d6b29 | 276 | if (!tuners) |
4d5dcc42 | 277 | return -ENOMEM; |
4d5dcc42 | 278 | |
4d5dcc42 | 279 | tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; |
98765847 | 280 | tuners->freq_step = DEF_FREQUENCY_STEP; |
ff4b1789 VK |
281 | dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; |
282 | dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; | |
283 | dbs_data->ignore_nice_load = 0; | |
4d5dcc42 VK |
284 | |
285 | dbs_data->tuners = tuners; | |
286 | dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO * | |
287 | jiffies_to_usecs(10); | |
8e0484d2 | 288 | |
4d5dcc42 VK |
289 | return 0; |
290 | } | |
291 | ||
9a15fb2c | 292 | static void cs_exit(struct dbs_data *dbs_data) |
4d5dcc42 VK |
293 | { |
294 | kfree(dbs_data->tuners); | |
295 | } | |
296 | ||
702c9e54 RW |
297 | static void cs_start(struct cpufreq_policy *policy) |
298 | { | |
7d5a9956 | 299 | struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data); |
702c9e54 RW |
300 | |
301 | dbs_info->down_skip = 0; | |
abb66279 | 302 | dbs_info->requested_freq = policy->cur; |
702c9e54 RW |
303 | } |
304 | ||
d352cf47 RW |
305 | static struct dbs_governor cs_governor = { |
306 | .gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"), | |
307 | .kobj_type = { .default_attrs = cs_attributes }, | |
26f0dbc9 | 308 | .gov_dbs_update = cs_dbs_update, |
d352cf47 RW |
309 | .alloc = cs_alloc, |
310 | .free = cs_free, | |
311 | .init = cs_init, | |
312 | .exit = cs_exit, | |
313 | .start = cs_start, | |
4471a34f | 314 | }; |
b9170836 | 315 | |
d352cf47 | 316 | #define CPU_FREQ_GOV_CONSERVATIVE (&cs_governor.gov) |
af926185 | 317 | |
b9170836 DJ |
318 | static int __init cpufreq_gov_dbs_init(void) |
319 | { | |
af926185 | 320 | return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
321 | } |
322 | ||
323 | static void __exit cpufreq_gov_dbs_exit(void) | |
324 | { | |
af926185 | 325 | cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
326 | } |
327 | ||
11a80a9c | 328 | MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); |
9acef487 | 329 | MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
b9170836 DJ |
330 | "Low Latency Frequency Transition capable processors " |
331 | "optimised for use in a battery environment"); | |
9acef487 | 332 | MODULE_LICENSE("GPL"); |
b9170836 | 333 | |
6915719b | 334 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
de1df26b RW |
335 | struct cpufreq_governor *cpufreq_default_governor(void) |
336 | { | |
af926185 | 337 | return CPU_FREQ_GOV_CONSERVATIVE; |
de1df26b RW |
338 | } |
339 | ||
6915719b JW |
340 | fs_initcall(cpufreq_gov_dbs_init); |
341 | #else | |
b9170836 | 342 | module_init(cpufreq_gov_dbs_init); |
6915719b | 343 | #endif |
b9170836 | 344 | module_exit(cpufreq_gov_dbs_exit); |