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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/cpufreq/cpufreq_conservative.c
4 *
5 * Copyright (C) 2001 Russell King
6 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
7 * Jun Nakajima <jun.nakajima@intel.com>
8 * (C) 2009 Alexander Clouter <alex@digriz.org.uk>
9 */
10
11#include <linux/slab.h>
12#include "cpufreq_governor.h"
13
14struct cs_policy_dbs_info {
15 struct policy_dbs_info policy_dbs;
16 unsigned int down_skip;
17 unsigned int requested_freq;
18};
19
20static inline struct cs_policy_dbs_info *to_dbs_info(struct policy_dbs_info *policy_dbs)
21{
22 return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs);
23}
24
25struct cs_dbs_tuners {
26 unsigned int down_threshold;
27 unsigned int freq_step;
28};
29
30/* Conservative governor macros */
31#define DEF_FREQUENCY_UP_THRESHOLD (80)
32#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
33#define DEF_FREQUENCY_STEP (5)
34#define DEF_SAMPLING_DOWN_FACTOR (1)
35#define MAX_SAMPLING_DOWN_FACTOR (10)
36
37static inline unsigned int get_freq_step(struct cs_dbs_tuners *cs_tuners,
38 struct cpufreq_policy *policy)
39{
40 unsigned int freq_step = (cs_tuners->freq_step * policy->max) / 100;
41
42 /* max freq cannot be less than 100. But who knows... */
43 if (unlikely(freq_step == 0))
44 freq_step = DEF_FREQUENCY_STEP;
45
46 return freq_step;
47}
48
49/*
50 * Every sampling_rate, we check, if current idle time is less than 20%
51 * (default), then we try to increase frequency. Every sampling_rate *
52 * sampling_down_factor, we check, if current idle time is more than 80%
53 * (default), then we try to decrease frequency
54 *
55 * Frequency updates happen at minimum steps of 5% (default) of maximum
56 * frequency
57 */
58static unsigned int cs_dbs_update(struct cpufreq_policy *policy)
59{
60 struct policy_dbs_info *policy_dbs = policy->governor_data;
61 struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs);
62 unsigned int requested_freq = dbs_info->requested_freq;
63 struct dbs_data *dbs_data = policy_dbs->dbs_data;
64 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
65 unsigned int load = dbs_update(policy);
66 unsigned int freq_step;
67
68 /*
69 * break out if we 'cannot' reduce the speed as the user might
70 * want freq_step to be zero
71 */
72 if (cs_tuners->freq_step == 0)
73 goto out;
74
75 /*
76 * If requested_freq is out of range, it is likely that the limits
77 * changed in the meantime, so fall back to current frequency in that
78 * case.
79 */
80 if (requested_freq > policy->max || requested_freq < policy->min) {
81 requested_freq = policy->cur;
82 dbs_info->requested_freq = requested_freq;
83 }
84
85 freq_step = get_freq_step(cs_tuners, policy);
86
87 /*
88 * Decrease requested_freq one freq_step for each idle period that
89 * we didn't update the frequency.
90 */
91 if (policy_dbs->idle_periods < UINT_MAX) {
92 unsigned int freq_steps = policy_dbs->idle_periods * freq_step;
93
94 if (requested_freq > policy->min + freq_steps)
95 requested_freq -= freq_steps;
96 else
97 requested_freq = policy->min;
98
99 policy_dbs->idle_periods = UINT_MAX;
100 }
101
102 /* Check for frequency increase */
103 if (load > dbs_data->up_threshold) {
104 dbs_info->down_skip = 0;
105
106 /* if we are already at full speed then break out early */
107 if (requested_freq == policy->max)
108 goto out;
109
110 requested_freq += freq_step;
111 if (requested_freq > policy->max)
112 requested_freq = policy->max;
113
114 __cpufreq_driver_target(policy, requested_freq,
115 CPUFREQ_RELATION_HE);
116 dbs_info->requested_freq = requested_freq;
117 goto out;
118 }
119
120 /* if sampling_down_factor is active break out early */
121 if (++dbs_info->down_skip < dbs_data->sampling_down_factor)
122 goto out;
123 dbs_info->down_skip = 0;
124
125 /* Check for frequency decrease */
126 if (load < cs_tuners->down_threshold) {
127 /*
128 * if we cannot reduce the frequency anymore, break out early
129 */
130 if (requested_freq == policy->min)
131 goto out;
132
133 if (requested_freq > freq_step)
134 requested_freq -= freq_step;
135 else
136 requested_freq = policy->min;
137
138 __cpufreq_driver_target(policy, requested_freq,
139 CPUFREQ_RELATION_LE);
140 dbs_info->requested_freq = requested_freq;
141 }
142
143 out:
144 return dbs_data->sampling_rate;
145}
146
147/************************** sysfs interface ************************/
148
149static ssize_t sampling_down_factor_store(struct gov_attr_set *attr_set,
150 const char *buf, size_t count)
151{
152 struct dbs_data *dbs_data = to_dbs_data(attr_set);
153 unsigned int input;
154 int ret;
155 ret = sscanf(buf, "%u", &input);
156
157 if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
158 return -EINVAL;
159
160 dbs_data->sampling_down_factor = input;
161 return count;
162}
163
164static ssize_t up_threshold_store(struct gov_attr_set *attr_set,
165 const char *buf, size_t count)
166{
167 struct dbs_data *dbs_data = to_dbs_data(attr_set);
168 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
169 unsigned int input;
170 int ret;
171 ret = sscanf(buf, "%u", &input);
172
173 if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold)
174 return -EINVAL;
175
176 dbs_data->up_threshold = input;
177 return count;
178}
179
180static ssize_t down_threshold_store(struct gov_attr_set *attr_set,
181 const char *buf, size_t count)
182{
183 struct dbs_data *dbs_data = to_dbs_data(attr_set);
184 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
185 unsigned int input;
186 int ret;
187 ret = sscanf(buf, "%u", &input);
188
189 /* cannot be lower than 1 otherwise freq will not fall */
190 if (ret != 1 || input < 1 || input >= dbs_data->up_threshold)
191 return -EINVAL;
192
193 cs_tuners->down_threshold = input;
194 return count;
195}
196
197static ssize_t ignore_nice_load_store(struct gov_attr_set *attr_set,
198 const char *buf, size_t count)
199{
200 struct dbs_data *dbs_data = to_dbs_data(attr_set);
201 unsigned int input;
202 int ret;
203
204 ret = sscanf(buf, "%u", &input);
205 if (ret != 1)
206 return -EINVAL;
207
208 if (input > 1)
209 input = 1;
210
211 if (input == dbs_data->ignore_nice_load) /* nothing to do */
212 return count;
213
214 dbs_data->ignore_nice_load = input;
215
216 /* we need to re-evaluate prev_cpu_idle */
217 gov_update_cpu_data(dbs_data);
218
219 return count;
220}
221
222static ssize_t freq_step_store(struct gov_attr_set *attr_set, const char *buf,
223 size_t count)
224{
225 struct dbs_data *dbs_data = to_dbs_data(attr_set);
226 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
227 unsigned int input;
228 int ret;
229 ret = sscanf(buf, "%u", &input);
230
231 if (ret != 1)
232 return -EINVAL;
233
234 if (input > 100)
235 input = 100;
236
237 /*
238 * no need to test here if freq_step is zero as the user might actually
239 * want this, they would be crazy though :)
240 */
241 cs_tuners->freq_step = input;
242 return count;
243}
244
245gov_show_one_common(sampling_rate);
246gov_show_one_common(sampling_down_factor);
247gov_show_one_common(up_threshold);
248gov_show_one_common(ignore_nice_load);
249gov_show_one(cs, down_threshold);
250gov_show_one(cs, freq_step);
251
252gov_attr_rw(sampling_rate);
253gov_attr_rw(sampling_down_factor);
254gov_attr_rw(up_threshold);
255gov_attr_rw(ignore_nice_load);
256gov_attr_rw(down_threshold);
257gov_attr_rw(freq_step);
258
259static struct attribute *cs_attrs[] = {
260 &sampling_rate.attr,
261 &sampling_down_factor.attr,
262 &up_threshold.attr,
263 &down_threshold.attr,
264 &ignore_nice_load.attr,
265 &freq_step.attr,
266 NULL
267};
268ATTRIBUTE_GROUPS(cs);
269
270/************************** sysfs end ************************/
271
272static struct policy_dbs_info *cs_alloc(void)
273{
274 struct cs_policy_dbs_info *dbs_info;
275
276 dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL);
277 return dbs_info ? &dbs_info->policy_dbs : NULL;
278}
279
280static void cs_free(struct policy_dbs_info *policy_dbs)
281{
282 kfree(to_dbs_info(policy_dbs));
283}
284
285static int cs_init(struct dbs_data *dbs_data)
286{
287 struct cs_dbs_tuners *tuners;
288
289 tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
290 if (!tuners)
291 return -ENOMEM;
292
293 tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
294 tuners->freq_step = DEF_FREQUENCY_STEP;
295 dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
296 dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
297 dbs_data->ignore_nice_load = 0;
298 dbs_data->tuners = tuners;
299
300 return 0;
301}
302
303static void cs_exit(struct dbs_data *dbs_data)
304{
305 kfree(dbs_data->tuners);
306}
307
308static void cs_start(struct cpufreq_policy *policy)
309{
310 struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data);
311
312 dbs_info->down_skip = 0;
313 dbs_info->requested_freq = policy->cur;
314}
315
316static struct dbs_governor cs_governor = {
317 .gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"),
318 .kobj_type = { .default_groups = cs_groups },
319 .gov_dbs_update = cs_dbs_update,
320 .alloc = cs_alloc,
321 .free = cs_free,
322 .init = cs_init,
323 .exit = cs_exit,
324 .start = cs_start,
325};
326
327#define CPU_FREQ_GOV_CONSERVATIVE (cs_governor.gov)
328
329MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
330MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
331 "Low Latency Frequency Transition capable processors "
332 "optimised for use in a battery environment");
333MODULE_LICENSE("GPL");
334
335#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
336struct cpufreq_governor *cpufreq_default_governor(void)
337{
338 return &CPU_FREQ_GOV_CONSERVATIVE;
339}
340#endif
341
342cpufreq_governor_init(CPU_FREQ_GOV_CONSERVATIVE);
343cpufreq_governor_exit(CPU_FREQ_GOV_CONSERVATIVE);
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) 2009 Alexander Clouter <alex@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/slab.h>
15#include "cpufreq_governor.h"
16
17struct cs_policy_dbs_info {
18 struct policy_dbs_info policy_dbs;
19 unsigned int down_skip;
20 unsigned int requested_freq;
21};
22
23static 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
28struct cs_dbs_tuners {
29 unsigned int down_threshold;
30 unsigned int freq_step;
31};
32
33/* Conservative governor macros */
34#define DEF_FREQUENCY_UP_THRESHOLD (80)
35#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
36#define DEF_FREQUENCY_STEP (5)
37#define DEF_SAMPLING_DOWN_FACTOR (1)
38#define MAX_SAMPLING_DOWN_FACTOR (10)
39
40static inline unsigned int get_freq_step(struct cs_dbs_tuners *cs_tuners,
41 struct cpufreq_policy *policy)
42{
43 unsigned int freq_step = (cs_tuners->freq_step * policy->max) / 100;
44
45 /* max freq cannot be less than 100. But who knows... */
46 if (unlikely(freq_step == 0))
47 freq_step = DEF_FREQUENCY_STEP;
48
49 return freq_step;
50}
51
52/*
53 * Every sampling_rate, we check, if current idle time is less than 20%
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
57 *
58 * Frequency updates happen at minimum steps of 5% (default) of maximum
59 * frequency
60 */
61static unsigned int cs_dbs_update(struct cpufreq_policy *policy)
62{
63 struct policy_dbs_info *policy_dbs = policy->governor_data;
64 struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs);
65 unsigned int requested_freq = dbs_info->requested_freq;
66 struct dbs_data *dbs_data = policy_dbs->dbs_data;
67 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
68 unsigned int load = dbs_update(policy);
69 unsigned int freq_step;
70
71 /*
72 * break out if we 'cannot' reduce the speed as the user might
73 * want freq_step to be zero
74 */
75 if (cs_tuners->freq_step == 0)
76 goto out;
77
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 */
83 if (requested_freq > policy->max || requested_freq < policy->min)
84 requested_freq = policy->cur;
85
86 freq_step = get_freq_step(cs_tuners, policy);
87
88 /*
89 * Decrease requested_freq one freq_step for each idle period that
90 * we didn't update the frequency.
91 */
92 if (policy_dbs->idle_periods < UINT_MAX) {
93 unsigned int freq_steps = policy_dbs->idle_periods * freq_step;
94
95 if (requested_freq > freq_steps)
96 requested_freq -= freq_steps;
97 else
98 requested_freq = policy->min;
99
100 policy_dbs->idle_periods = UINT_MAX;
101 }
102
103 /* Check for frequency increase */
104 if (load > dbs_data->up_threshold) {
105 dbs_info->down_skip = 0;
106
107 /* if we are already at full speed then break out early */
108 if (requested_freq == policy->max)
109 goto out;
110
111 requested_freq += freq_step;
112 if (requested_freq > policy->max)
113 requested_freq = policy->max;
114
115 __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_H);
116 dbs_info->requested_freq = requested_freq;
117 goto out;
118 }
119
120 /* if sampling_down_factor is active break out early */
121 if (++dbs_info->down_skip < dbs_data->sampling_down_factor)
122 goto out;
123 dbs_info->down_skip = 0;
124
125 /* Check for frequency decrease */
126 if (load < cs_tuners->down_threshold) {
127 /*
128 * if we cannot reduce the frequency anymore, break out early
129 */
130 if (requested_freq == policy->min)
131 goto out;
132
133 if (requested_freq > freq_step)
134 requested_freq -= freq_step;
135 else
136 requested_freq = policy->min;
137
138 __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_L);
139 dbs_info->requested_freq = requested_freq;
140 }
141
142 out:
143 return dbs_data->sampling_rate;
144}
145
146/************************** sysfs interface ************************/
147
148static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set,
149 const char *buf, size_t count)
150{
151 struct dbs_data *dbs_data = to_dbs_data(attr_set);
152 unsigned int input;
153 int ret;
154 ret = sscanf(buf, "%u", &input);
155
156 if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
157 return -EINVAL;
158
159 dbs_data->sampling_down_factor = input;
160 return count;
161}
162
163static ssize_t store_up_threshold(struct gov_attr_set *attr_set,
164 const char *buf, size_t count)
165{
166 struct dbs_data *dbs_data = to_dbs_data(attr_set);
167 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
168 unsigned int input;
169 int ret;
170 ret = sscanf(buf, "%u", &input);
171
172 if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold)
173 return -EINVAL;
174
175 dbs_data->up_threshold = input;
176 return count;
177}
178
179static ssize_t store_down_threshold(struct gov_attr_set *attr_set,
180 const char *buf, size_t count)
181{
182 struct dbs_data *dbs_data = to_dbs_data(attr_set);
183 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
184 unsigned int input;
185 int ret;
186 ret = sscanf(buf, "%u", &input);
187
188 /* cannot be lower than 11 otherwise freq will not fall */
189 if (ret != 1 || input < 11 || input > 100 ||
190 input >= dbs_data->up_threshold)
191 return -EINVAL;
192
193 cs_tuners->down_threshold = input;
194 return count;
195}
196
197static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set,
198 const char *buf, size_t count)
199{
200 struct dbs_data *dbs_data = to_dbs_data(attr_set);
201 unsigned int input;
202 int ret;
203
204 ret = sscanf(buf, "%u", &input);
205 if (ret != 1)
206 return -EINVAL;
207
208 if (input > 1)
209 input = 1;
210
211 if (input == dbs_data->ignore_nice_load) /* nothing to do */
212 return count;
213
214 dbs_data->ignore_nice_load = input;
215
216 /* we need to re-evaluate prev_cpu_idle */
217 gov_update_cpu_data(dbs_data);
218
219 return count;
220}
221
222static ssize_t store_freq_step(struct gov_attr_set *attr_set, const char *buf,
223 size_t count)
224{
225 struct dbs_data *dbs_data = to_dbs_data(attr_set);
226 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
227 unsigned int input;
228 int ret;
229 ret = sscanf(buf, "%u", &input);
230
231 if (ret != 1)
232 return -EINVAL;
233
234 if (input > 100)
235 input = 100;
236
237 /*
238 * no need to test here if freq_step is zero as the user might actually
239 * want this, they would be crazy though :)
240 */
241 cs_tuners->freq_step = input;
242 return count;
243}
244
245gov_show_one_common(sampling_rate);
246gov_show_one_common(sampling_down_factor);
247gov_show_one_common(up_threshold);
248gov_show_one_common(ignore_nice_load);
249gov_show_one_common(min_sampling_rate);
250gov_show_one(cs, down_threshold);
251gov_show_one(cs, freq_step);
252
253gov_attr_rw(sampling_rate);
254gov_attr_rw(sampling_down_factor);
255gov_attr_rw(up_threshold);
256gov_attr_rw(ignore_nice_load);
257gov_attr_ro(min_sampling_rate);
258gov_attr_rw(down_threshold);
259gov_attr_rw(freq_step);
260
261static struct attribute *cs_attributes[] = {
262 &min_sampling_rate.attr,
263 &sampling_rate.attr,
264 &sampling_down_factor.attr,
265 &up_threshold.attr,
266 &down_threshold.attr,
267 &ignore_nice_load.attr,
268 &freq_step.attr,
269 NULL
270};
271
272/************************** sysfs end ************************/
273
274static struct policy_dbs_info *cs_alloc(void)
275{
276 struct cs_policy_dbs_info *dbs_info;
277
278 dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL);
279 return dbs_info ? &dbs_info->policy_dbs : NULL;
280}
281
282static void cs_free(struct policy_dbs_info *policy_dbs)
283{
284 kfree(to_dbs_info(policy_dbs));
285}
286
287static int cs_init(struct dbs_data *dbs_data)
288{
289 struct cs_dbs_tuners *tuners;
290
291 tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
292 if (!tuners)
293 return -ENOMEM;
294
295 tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
296 tuners->freq_step = DEF_FREQUENCY_STEP;
297 dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
298 dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
299 dbs_data->ignore_nice_load = 0;
300
301 dbs_data->tuners = tuners;
302 dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
303 jiffies_to_usecs(10);
304
305 return 0;
306}
307
308static void cs_exit(struct dbs_data *dbs_data)
309{
310 kfree(dbs_data->tuners);
311}
312
313static void cs_start(struct cpufreq_policy *policy)
314{
315 struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data);
316
317 dbs_info->down_skip = 0;
318 dbs_info->requested_freq = policy->cur;
319}
320
321static struct dbs_governor cs_governor = {
322 .gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"),
323 .kobj_type = { .default_attrs = cs_attributes },
324 .gov_dbs_update = cs_dbs_update,
325 .alloc = cs_alloc,
326 .free = cs_free,
327 .init = cs_init,
328 .exit = cs_exit,
329 .start = cs_start,
330};
331
332#define CPU_FREQ_GOV_CONSERVATIVE (&cs_governor.gov)
333
334static int __init cpufreq_gov_dbs_init(void)
335{
336 return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE);
337}
338
339static void __exit cpufreq_gov_dbs_exit(void)
340{
341 cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE);
342}
343
344MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
345MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
346 "Low Latency Frequency Transition capable processors "
347 "optimised for use in a battery environment");
348MODULE_LICENSE("GPL");
349
350#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
351struct cpufreq_governor *cpufreq_default_governor(void)
352{
353 return CPU_FREQ_GOV_CONSERVATIVE;
354}
355
356fs_initcall(cpufreq_gov_dbs_init);
357#else
358module_init(cpufreq_gov_dbs_init);
359#endif
360module_exit(cpufreq_gov_dbs_exit);