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; | |
7d5a9956 RW |
20 | }; |
21 | ||
22 | static inline struct cs_policy_dbs_info *to_dbs_info(struct policy_dbs_info *policy_dbs) | |
23 | { | |
24 | return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs); | |
25 | } | |
26 | ||
47ebaac1 RW |
27 | struct cs_dbs_tuners { |
28 | unsigned int down_threshold; | |
29 | unsigned int freq_step; | |
30 | }; | |
31 | ||
c88883cd | 32 | /* Conservative governor macros */ |
b9170836 | 33 | #define DEF_FREQUENCY_UP_THRESHOLD (80) |
b9170836 | 34 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
98765847 | 35 | #define DEF_FREQUENCY_STEP (5) |
2c906b31 AC |
36 | #define DEF_SAMPLING_DOWN_FACTOR (1) |
37 | #define MAX_SAMPLING_DOWN_FACTOR (10) | |
b9170836 | 38 | |
98765847 SK |
39 | static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners, |
40 | struct cpufreq_policy *policy) | |
41 | { | |
42 | unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100; | |
43 | ||
44 | /* max freq cannot be less than 100. But who knows... */ | |
45 | if (unlikely(freq_target == 0)) | |
46 | freq_target = DEF_FREQUENCY_STEP; | |
47 | ||
48 | return freq_target; | |
49 | } | |
50 | ||
4471a34f VK |
51 | /* |
52 | * Every sampling_rate, we check, if current idle time is less than 20% | |
7af1c056 SK |
53 | * (default), then we try to increase frequency. Every sampling_rate * |
54 | * sampling_down_factor, we check, if current idle time is more than 80% | |
55 | * (default), then we try to decrease frequency | |
4471a34f VK |
56 | * |
57 | * Any frequency increase takes it to the maximum frequency. Frequency reduction | |
58 | * happens at minimum steps of 5% (default) of maximum frequency | |
59 | */ | |
4cccf755 | 60 | static unsigned int cs_dbs_timer(struct cpufreq_policy *policy) |
a8d7c3bc | 61 | { |
bc505475 | 62 | struct policy_dbs_info *policy_dbs = policy->governor_data; |
7d5a9956 | 63 | struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs); |
bc505475 | 64 | struct dbs_data *dbs_data = policy_dbs->dbs_data; |
4d5dcc42 | 65 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
4cccf755 | 66 | unsigned int load = dbs_update(policy); |
4471a34f VK |
67 | |
68 | /* | |
69 | * break out if we 'cannot' reduce the speed as the user might | |
70 | * want freq_step to be zero | |
71 | */ | |
4d5dcc42 | 72 | if (cs_tuners->freq_step == 0) |
4cccf755 | 73 | goto out; |
4471a34f VK |
74 | |
75 | /* Check for frequency increase */ | |
ff4b1789 | 76 | if (load > dbs_data->up_threshold) { |
d352cf47 RW |
77 | unsigned int requested_freq = policy->cur; |
78 | ||
4471a34f VK |
79 | dbs_info->down_skip = 0; |
80 | ||
81 | /* if we are already at full speed then break out early */ | |
d352cf47 | 82 | if (requested_freq == policy->max) |
4cccf755 | 83 | goto out; |
4471a34f | 84 | |
d352cf47 | 85 | requested_freq += get_freq_target(cs_tuners, policy); |
6d7bcb14 | 86 | |
d352cf47 | 87 | __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_H); |
4cccf755 | 88 | goto out; |
4471a34f VK |
89 | } |
90 | ||
7af1c056 | 91 | /* if sampling_down_factor is active break out early */ |
ff4b1789 | 92 | if (++dbs_info->down_skip < dbs_data->sampling_down_factor) |
4cccf755 | 93 | goto out; |
7af1c056 SK |
94 | dbs_info->down_skip = 0; |
95 | ||
27ed3cd2 SK |
96 | /* Check for frequency decrease */ |
97 | if (load < cs_tuners->down_threshold) { | |
d352cf47 | 98 | unsigned int freq_target, requested_freq = policy->cur; |
4471a34f VK |
99 | /* |
100 | * if we cannot reduce the frequency anymore, break out early | |
101 | */ | |
d352cf47 | 102 | if (requested_freq == policy->min) |
4cccf755 | 103 | goto out; |
4471a34f | 104 | |
3baa976a | 105 | freq_target = get_freq_target(cs_tuners, policy); |
d352cf47 RW |
106 | if (requested_freq > freq_target) |
107 | requested_freq -= freq_target; | |
3baa976a | 108 | else |
d352cf47 | 109 | requested_freq = policy->min; |
ad529a9c | 110 | |
d352cf47 | 111 | __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_L); |
4471a34f | 112 | } |
43e0ee36 | 113 | |
4cccf755 | 114 | out: |
07aa4402 | 115 | return dbs_data->sampling_rate; |
66df2a01 FB |
116 | } |
117 | ||
b9170836 | 118 | /************************** sysfs interface ************************/ |
b9170836 | 119 | |
0dd3c1d6 RW |
120 | static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set, |
121 | const char *buf, size_t count) | |
b9170836 | 122 | { |
0dd3c1d6 | 123 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
b9170836 DJ |
124 | unsigned int input; |
125 | int ret; | |
9acef487 | 126 | ret = sscanf(buf, "%u", &input); |
8e677ce8 | 127 | |
2c906b31 | 128 | if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
b9170836 DJ |
129 | return -EINVAL; |
130 | ||
ff4b1789 | 131 | dbs_data->sampling_down_factor = input; |
b9170836 DJ |
132 | return count; |
133 | } | |
134 | ||
0dd3c1d6 RW |
135 | static ssize_t store_up_threshold(struct gov_attr_set *attr_set, |
136 | const char *buf, size_t count) | |
b9170836 | 137 | { |
0dd3c1d6 | 138 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
4d5dcc42 | 139 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
140 | unsigned int input; |
141 | int ret; | |
9acef487 | 142 | ret = sscanf(buf, "%u", &input); |
b9170836 | 143 | |
4d5dcc42 | 144 | if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold) |
b9170836 | 145 | return -EINVAL; |
b9170836 | 146 | |
ff4b1789 | 147 | dbs_data->up_threshold = input; |
b9170836 DJ |
148 | return count; |
149 | } | |
150 | ||
0dd3c1d6 RW |
151 | static ssize_t store_down_threshold(struct gov_attr_set *attr_set, |
152 | const char *buf, size_t count) | |
b9170836 | 153 | { |
0dd3c1d6 | 154 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
4d5dcc42 | 155 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
156 | unsigned int input; |
157 | int ret; | |
9acef487 | 158 | ret = sscanf(buf, "%u", &input); |
b9170836 | 159 | |
8e677ce8 AC |
160 | /* cannot be lower than 11 otherwise freq will not fall */ |
161 | if (ret != 1 || input < 11 || input > 100 || | |
ff4b1789 | 162 | input >= dbs_data->up_threshold) |
b9170836 | 163 | return -EINVAL; |
b9170836 | 164 | |
4d5dcc42 | 165 | cs_tuners->down_threshold = input; |
b9170836 DJ |
166 | return count; |
167 | } | |
168 | ||
0dd3c1d6 RW |
169 | static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set, |
170 | const char *buf, size_t count) | |
b9170836 | 171 | { |
0dd3c1d6 | 172 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
a33cce1c | 173 | unsigned int input; |
b9170836 DJ |
174 | int ret; |
175 | ||
18a7247d DJ |
176 | ret = sscanf(buf, "%u", &input); |
177 | if (ret != 1) | |
b9170836 DJ |
178 | return -EINVAL; |
179 | ||
18a7247d | 180 | if (input > 1) |
b9170836 | 181 | input = 1; |
18a7247d | 182 | |
ff4b1789 | 183 | if (input == dbs_data->ignore_nice_load) /* nothing to do */ |
b9170836 | 184 | return count; |
326c86de | 185 | |
ff4b1789 | 186 | dbs_data->ignore_nice_load = input; |
b9170836 | 187 | |
8e677ce8 | 188 | /* we need to re-evaluate prev_cpu_idle */ |
8c8f77fd | 189 | gov_update_cpu_data(dbs_data); |
a33cce1c | 190 | |
b9170836 DJ |
191 | return count; |
192 | } | |
193 | ||
0dd3c1d6 RW |
194 | static ssize_t store_freq_step(struct gov_attr_set *attr_set, const char *buf, |
195 | size_t count) | |
b9170836 | 196 | { |
0dd3c1d6 | 197 | struct dbs_data *dbs_data = to_dbs_data(attr_set); |
4d5dcc42 | 198 | struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
b9170836 DJ |
199 | unsigned int input; |
200 | int ret; | |
18a7247d | 201 | ret = sscanf(buf, "%u", &input); |
b9170836 | 202 | |
18a7247d | 203 | if (ret != 1) |
b9170836 DJ |
204 | return -EINVAL; |
205 | ||
18a7247d | 206 | if (input > 100) |
b9170836 | 207 | input = 100; |
18a7247d | 208 | |
4471a34f VK |
209 | /* |
210 | * no need to test here if freq_step is zero as the user might actually | |
211 | * want this, they would be crazy though :) | |
212 | */ | |
4d5dcc42 | 213 | cs_tuners->freq_step = input; |
b9170836 DJ |
214 | return count; |
215 | } | |
216 | ||
c4435630 VK |
217 | gov_show_one_common(sampling_rate); |
218 | gov_show_one_common(sampling_down_factor); | |
219 | gov_show_one_common(up_threshold); | |
220 | gov_show_one_common(ignore_nice_load); | |
221 | gov_show_one_common(min_sampling_rate); | |
222 | gov_show_one(cs, down_threshold); | |
223 | gov_show_one(cs, freq_step); | |
224 | ||
225 | gov_attr_rw(sampling_rate); | |
226 | gov_attr_rw(sampling_down_factor); | |
227 | gov_attr_rw(up_threshold); | |
228 | gov_attr_rw(ignore_nice_load); | |
229 | gov_attr_ro(min_sampling_rate); | |
230 | gov_attr_rw(down_threshold); | |
231 | gov_attr_rw(freq_step); | |
232 | ||
233 | static struct attribute *cs_attributes[] = { | |
234 | &min_sampling_rate.attr, | |
235 | &sampling_rate.attr, | |
236 | &sampling_down_factor.attr, | |
237 | &up_threshold.attr, | |
238 | &down_threshold.attr, | |
239 | &ignore_nice_load.attr, | |
240 | &freq_step.attr, | |
b9170836 DJ |
241 | NULL |
242 | }; | |
243 | ||
b9170836 DJ |
244 | /************************** sysfs end ************************/ |
245 | ||
7d5a9956 RW |
246 | static struct policy_dbs_info *cs_alloc(void) |
247 | { | |
248 | struct cs_policy_dbs_info *dbs_info; | |
249 | ||
250 | dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL); | |
251 | return dbs_info ? &dbs_info->policy_dbs : NULL; | |
252 | } | |
253 | ||
254 | static void cs_free(struct policy_dbs_info *policy_dbs) | |
255 | { | |
256 | kfree(to_dbs_info(policy_dbs)); | |
257 | } | |
258 | ||
9a15fb2c | 259 | static int cs_init(struct dbs_data *dbs_data) |
4d5dcc42 VK |
260 | { |
261 | struct cs_dbs_tuners *tuners; | |
262 | ||
d5b73cd8 | 263 | tuners = kzalloc(sizeof(*tuners), GFP_KERNEL); |
a69d6b29 | 264 | if (!tuners) |
4d5dcc42 | 265 | return -ENOMEM; |
4d5dcc42 | 266 | |
4d5dcc42 | 267 | tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; |
98765847 | 268 | tuners->freq_step = DEF_FREQUENCY_STEP; |
ff4b1789 VK |
269 | dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; |
270 | dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; | |
271 | dbs_data->ignore_nice_load = 0; | |
4d5dcc42 VK |
272 | |
273 | dbs_data->tuners = tuners; | |
274 | dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO * | |
275 | jiffies_to_usecs(10); | |
8e0484d2 | 276 | |
4d5dcc42 VK |
277 | return 0; |
278 | } | |
279 | ||
9a15fb2c | 280 | static void cs_exit(struct dbs_data *dbs_data) |
4d5dcc42 VK |
281 | { |
282 | kfree(dbs_data->tuners); | |
283 | } | |
284 | ||
702c9e54 RW |
285 | static void cs_start(struct cpufreq_policy *policy) |
286 | { | |
7d5a9956 | 287 | struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data); |
702c9e54 RW |
288 | |
289 | dbs_info->down_skip = 0; | |
702c9e54 RW |
290 | } |
291 | ||
d352cf47 RW |
292 | static struct dbs_governor cs_governor = { |
293 | .gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"), | |
294 | .kobj_type = { .default_attrs = cs_attributes }, | |
295 | .gov_dbs_timer = cs_dbs_timer, | |
296 | .alloc = cs_alloc, | |
297 | .free = cs_free, | |
298 | .init = cs_init, | |
299 | .exit = cs_exit, | |
300 | .start = cs_start, | |
4471a34f | 301 | }; |
b9170836 | 302 | |
d352cf47 | 303 | #define CPU_FREQ_GOV_CONSERVATIVE (&cs_governor.gov) |
af926185 | 304 | |
b9170836 DJ |
305 | static int __init cpufreq_gov_dbs_init(void) |
306 | { | |
af926185 | 307 | return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
308 | } |
309 | ||
310 | static void __exit cpufreq_gov_dbs_exit(void) | |
311 | { | |
af926185 | 312 | cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE); |
b9170836 DJ |
313 | } |
314 | ||
11a80a9c | 315 | MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); |
9acef487 | 316 | MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
b9170836 DJ |
317 | "Low Latency Frequency Transition capable processors " |
318 | "optimised for use in a battery environment"); | |
9acef487 | 319 | MODULE_LICENSE("GPL"); |
b9170836 | 320 | |
6915719b | 321 | #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
de1df26b RW |
322 | struct cpufreq_governor *cpufreq_default_governor(void) |
323 | { | |
af926185 | 324 | return CPU_FREQ_GOV_CONSERVATIVE; |
de1df26b RW |
325 | } |
326 | ||
6915719b JW |
327 | fs_initcall(cpufreq_gov_dbs_init); |
328 | #else | |
b9170836 | 329 | module_init(cpufreq_gov_dbs_init); |
6915719b | 330 | #endif |
b9170836 | 331 | module_exit(cpufreq_gov_dbs_exit); |