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; | |
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 | |
d5f905a9 VK |
40 | static inline unsigned int get_freq_step(struct cs_dbs_tuners *cs_tuners, |
41 | struct cpufreq_policy *policy) | |
98765847 | 42 | { |
d5f905a9 | 43 | unsigned int freq_step = (cs_tuners->freq_step * policy->max) / 100; |
98765847 SK |
44 | |
45 | /* max freq cannot be less than 100. But who knows... */ | |
d5f905a9 VK |
46 | if (unlikely(freq_step == 0)) |
47 | freq_step = DEF_FREQUENCY_STEP; | |
98765847 | 48 | |
d5f905a9 | 49 | return freq_step; |
98765847 SK |
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 | 57 | * |
42d951c8 SK |
58 | * Frequency updates happen at minimum steps of 5% (default) of maximum |
59 | * frequency | |
4471a34f | 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); |
00bfe058 | 69 | unsigned int freq_step; |
4471a34f VK |
70 | |
71 | /* | |
72 | * break out if we 'cannot' reduce the speed as the user might | |
73 | * want freq_step to be zero | |
74 | */ | |
4d5dcc42 | 75 | if (cs_tuners->freq_step == 0) |
4cccf755 | 76 | goto out; |
4471a34f | 77 | |
abb66279 RW |
78 | /* |
79 | * If requested_freq is out of range, it is likely that the limits | |
80 | * changed in the meantime, so fall back to current frequency in that | |
81 | * case. | |
82 | */ | |
da5e79bc | 83 | if (requested_freq > policy->max || requested_freq < policy->min) { |
abb66279 | 84 | requested_freq = policy->cur; |
da5e79bc RW |
85 | dbs_info->requested_freq = requested_freq; |
86 | } | |
abb66279 | 87 | |
00bfe058 SK |
88 | freq_step = get_freq_step(cs_tuners, policy); |
89 | ||
90 | /* | |
91 | * Decrease requested_freq one freq_step for each idle period that | |
92 | * we didn't update the frequency. | |
93 | */ | |
94 | if (policy_dbs->idle_periods < UINT_MAX) { | |
95 | unsigned int freq_steps = policy_dbs->idle_periods * freq_step; | |
96 | ||
da5e79bc | 97 | if (requested_freq > policy->min + freq_steps) |
00bfe058 SK |
98 | requested_freq -= freq_steps; |
99 | else | |
100 | requested_freq = policy->min; | |
101 | ||
102 | policy_dbs->idle_periods = UINT_MAX; | |
103 | } | |
104 | ||
4471a34f | 105 | /* Check for frequency increase */ |
ff4b1789 | 106 | if (load > dbs_data->up_threshold) { |
4471a34f VK |
107 | dbs_info->down_skip = 0; |
108 | ||
109 | /* if we are already at full speed then break out early */ | |
d352cf47 | 110 | if (requested_freq == policy->max) |
4cccf755 | 111 | goto out; |
4471a34f | 112 | |
00bfe058 | 113 | requested_freq += freq_step; |
abb66279 RW |
114 | if (requested_freq > policy->max) |
115 | requested_freq = policy->max; | |
6d7bcb14 | 116 | |
d352cf47 | 117 | __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_H); |
abb66279 | 118 | dbs_info->requested_freq = requested_freq; |
4cccf755 | 119 | goto out; |
4471a34f VK |
120 | } |
121 | ||
7af1c056 | 122 | /* if sampling_down_factor is active break out early */ |
ff4b1789 | 123 | if (++dbs_info->down_skip < dbs_data->sampling_down_factor) |
4cccf755 | 124 | goto out; |
7af1c056 SK |
125 | dbs_info->down_skip = 0; |
126 | ||
27ed3cd2 SK |
127 | /* Check for frequency decrease */ |
128 | if (load < cs_tuners->down_threshold) { | |
4471a34f VK |
129 | /* |
130 | * if we cannot reduce the frequency anymore, break out early | |
131 | */ | |
d352cf47 | 132 | if (requested_freq == policy->min) |
4cccf755 | 133 | goto out; |
4471a34f | 134 | |
d5f905a9 VK |
135 | if (requested_freq > freq_step) |
136 | requested_freq -= freq_step; | |
3baa976a | 137 | else |
d352cf47 | 138 | requested_freq = policy->min; |
ad529a9c | 139 | |
d352cf47 | 140 | __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_L); |
abb66279 | 141 | dbs_info->requested_freq = requested_freq; |
4471a34f | 142 | } |
43e0ee36 | 143 | |
4cccf755 | 144 | out: |
07aa4402 | 145 | return dbs_data->sampling_rate; |
66df2a01 FB |
146 | } |
147 | ||
b9170836 | 148 | /************************** sysfs interface ************************/ |
b9170836 | 149 | |
0dd3c1d6 RW |
150 | static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set, |
151 | const char *buf, size_t count) | |
b9170836 | 152 | { |
0dd3c1d6 | 153 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
b9170836 DJ |
154 | unsigned int input; |
155 | int ret; | |
9acef487 | 156 | ret = sscanf(buf, "%u", &input); |
8e677ce8 | 157 | |
2c906b31 | 158 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
159 | return -EINVAL; |
160 | ||
ff4b1789 | 161 | dbs_data->sampling_down_factor = input; |
b9170836 DJ |
162 | return count; |
163 | } | |
164 | ||
0dd3c1d6 RW |
165 | static ssize_t store_up_threshold(struct gov_attr_set *attr_set, |
166 | const char *buf, size_t count) | |
b9170836 | 167 | { |
0dd3c1d6 | 168 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
4d5dcc42 | 169 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
170 | unsigned int input; |
171 | int ret; | |
9acef487 | 172 | ret = sscanf(buf, "%u", &input); |
b9170836 | 173 | |
4d5dcc42 | 174 | if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold) |
b9170836 | 175 | return -EINVAL; |
b9170836 | 176 | |
ff4b1789 | 177 | dbs_data->up_threshold = input; |
b9170836 DJ |
178 | return count; |
179 | } | |
180 | ||
0dd3c1d6 RW |
181 | static ssize_t store_down_threshold(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); |
4d5dcc42 | 185 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
186 | unsigned int input; |
187 | int ret; | |
9acef487 | 188 | ret = sscanf(buf, "%u", &input); |
b9170836 | 189 | |
b8e11f7d TW |
190 | /* cannot be lower than 1 otherwise freq will not fall */ |
191 | if (ret != 1 || input < 1 || input > 100 || | |
ff4b1789 | 192 | input >= dbs_data->up_threshold) |
b9170836 | 193 | return -EINVAL; |
b9170836 | 194 | |
4d5dcc42 | 195 | cs_tuners->down_threshold = input; |
b9170836 DJ |
196 | return count; |
197 | } | |
198 | ||
0dd3c1d6 RW |
199 | static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set, |
200 | const char *buf, size_t count) | |
b9170836 | 201 | { |
0dd3c1d6 | 202 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
a33cce1c | 203 | unsigned int input; |
b9170836 DJ |
204 | int ret; |
205 | ||
18a7247d DJ |
206 | ret = sscanf(buf, "%u", &input); |
207 | if (ret != 1) | |
b9170836 DJ |
208 | return -EINVAL; |
209 | ||
18a7247d | 210 | if (input > 1) |
b9170836 | 211 | input = 1; |
18a7247d | 212 | |
ff4b1789 | 213 | if (input == dbs_data->ignore_nice_load) /* nothing to do */ |
b9170836 | 214 | return count; |
326c86de | 215 | |
ff4b1789 | 216 | dbs_data->ignore_nice_load = input; |
b9170836 | 217 | |
8e677ce8 | 218 | /* we need to re-evaluate prev_cpu_idle */ |
8c8f77fd | 219 | gov_update_cpu_data(dbs_data); |
a33cce1c | 220 | |
b9170836 DJ |
221 | return count; |
222 | } | |
223 | ||
0dd3c1d6 RW |
224 | static ssize_t store_freq_step(struct gov_attr_set *attr_set, const char *buf, |
225 | size_t count) | |
b9170836 | 226 | { |
0dd3c1d6 | 227 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
4d5dcc42 | 228 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
229 | unsigned int input; |
230 | int ret; | |
18a7247d | 231 | ret = sscanf(buf, "%u", &input); |
b9170836 | 232 | |
18a7247d | 233 | if (ret != 1) |
b9170836 DJ |
234 | return -EINVAL; |
235 | ||
18a7247d | 236 | if (input > 100) |
b9170836 | 237 | input = 100; |
18a7247d | 238 | |
4471a34f VK |
239 | /* |
240 | * no need to test here if freq_step is zero as the user might actually | |
241 | * want this, they would be crazy though :) | |
242 | */ | |
4d5dcc42 | 243 | cs_tuners->freq_step = input; |
b9170836 DJ |
244 | return count; |
245 | } | |
246 | ||
c4435630 VK |
247 | gov_show_one_common(sampling_rate); |
248 | gov_show_one_common(sampling_down_factor); | |
249 | gov_show_one_common(up_threshold); | |
250 | gov_show_one_common(ignore_nice_load); | |
c4435630 VK |
251 | gov_show_one(cs, down_threshold); |
252 | gov_show_one(cs, freq_step); | |
253 | ||
254 | gov_attr_rw(sampling_rate); | |
255 | gov_attr_rw(sampling_down_factor); | |
256 | gov_attr_rw(up_threshold); | |
257 | gov_attr_rw(ignore_nice_load); | |
c4435630 VK |
258 | gov_attr_rw(down_threshold); |
259 | gov_attr_rw(freq_step); | |
260 | ||
261 | static struct attribute *cs_attributes[] = { | |
c4435630 VK |
262 | &sampling_rate.attr, |
263 | &sampling_down_factor.attr, | |
264 | &up_threshold.attr, | |
265 | &down_threshold.attr, | |
266 | &ignore_nice_load.attr, | |
267 | &freq_step.attr, | |
b9170836 DJ |
268 | NULL |
269 | }; | |
270 | ||
b9170836 DJ |
271 | /************************** sysfs end ************************/ |
272 | ||
7d5a9956 RW |
273 | static struct policy_dbs_info *cs_alloc(void) |
274 | { | |
275 | struct cs_policy_dbs_info *dbs_info; | |
276 | ||
277 | dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL); | |
278 | return dbs_info ? &dbs_info->policy_dbs : NULL; | |
279 | } | |
280 | ||
281 | static void cs_free(struct policy_dbs_info *policy_dbs) | |
282 | { | |
283 | kfree(to_dbs_info(policy_dbs)); | |
284 | } | |
285 | ||
9a15fb2c | 286 | static int cs_init(struct dbs_data *dbs_data) |
4d5dcc42 VK |
287 | { |
288 | struct cs_dbs_tuners *tuners; | |
289 | ||
d5b73cd8 | 290 | tuners = kzalloc(sizeof(*tuners), GFP_KERNEL); |
a69d6b29 | 291 | if (!tuners) |
4d5dcc42 | 292 | return -ENOMEM; |
4d5dcc42 | 293 | |
4d5dcc42 | 294 | tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; |
98765847 | 295 | tuners->freq_step = DEF_FREQUENCY_STEP; |
ff4b1789 VK |
296 | dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; |
297 | dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; | |
298 | dbs_data->ignore_nice_load = 0; | |
4d5dcc42 | 299 | dbs_data->tuners = tuners; |
8e0484d2 | 300 | |
4d5dcc42 VK |
301 | return 0; |
302 | } | |
303 | ||
9a15fb2c | 304 | static void cs_exit(struct dbs_data *dbs_data) |
4d5dcc42 VK |
305 | { |
306 | kfree(dbs_data->tuners); | |
307 | } | |
308 | ||
702c9e54 RW |
309 | static void cs_start(struct cpufreq_policy *policy) |
310 | { | |
7d5a9956 | 311 | struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data); |
702c9e54 RW |
312 | |
313 | dbs_info->down_skip = 0; | |
abb66279 | 314 | dbs_info->requested_freq = policy->cur; |
702c9e54 RW |
315 | } |
316 | ||
d352cf47 RW |
317 | static struct dbs_governor cs_governor = { |
318 | .gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"), | |
319 | .kobj_type = { .default_attrs = cs_attributes }, | |
26f0dbc9 | 320 | .gov_dbs_update = cs_dbs_update, |
d352cf47 RW |
321 | .alloc = cs_alloc, |
322 | .free = cs_free, | |
323 | .init = cs_init, | |
324 | .exit = cs_exit, | |
325 | .start = cs_start, | |
4471a34f | 326 | }; |
b9170836 | 327 | |
d352cf47 | 328 | #define CPU_FREQ_GOV_CONSERVATIVE (&cs_governor.gov) |
af926185 | 329 | |
b9170836 DJ |
330 | static int __init cpufreq_gov_dbs_init(void) |
331 | { | |
af926185 | 332 | return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
333 | } |
334 | ||
335 | static void __exit cpufreq_gov_dbs_exit(void) | |
336 | { | |
af926185 | 337 | cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
338 | } |
339 | ||
11a80a9c | 340 | MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); |
9acef487 | 341 | MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
b9170836 DJ |
342 | "Low Latency Frequency Transition capable processors " |
343 | "optimised for use in a battery environment"); | |
9acef487 | 344 | MODULE_LICENSE("GPL"); |
b9170836 | 345 | |
6915719b | 346 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
de1df26b RW |
347 | struct cpufreq_governor *cpufreq_default_governor(void) |
348 | { | |
af926185 | 349 | return CPU_FREQ_GOV_CONSERVATIVE; |
de1df26b RW |
350 | } |
351 | ||
6915719b JW |
352 | fs_initcall(cpufreq_gov_dbs_init); |
353 | #else | |
b9170836 | 354 | module_init(cpufreq_gov_dbs_init); |
6915719b | 355 | #endif |
b9170836 | 356 | module_exit(cpufreq_gov_dbs_exit); |