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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// 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, CPUFREQ_RELATION_H);
115 dbs_info->requested_freq = requested_freq;
116 goto out;
117 }
118
119 /* if sampling_down_factor is active break out early */
120 if (++dbs_info->down_skip < dbs_data->sampling_down_factor)
121 goto out;
122 dbs_info->down_skip = 0;
123
124 /* Check for frequency decrease */
125 if (load < cs_tuners->down_threshold) {
126 /*
127 * if we cannot reduce the frequency anymore, break out early
128 */
129 if (requested_freq == policy->min)
130 goto out;
131
132 if (requested_freq > freq_step)
133 requested_freq -= freq_step;
134 else
135 requested_freq = policy->min;
136
137 __cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_L);
138 dbs_info->requested_freq = requested_freq;
139 }
140
141 out:
142 return dbs_data->sampling_rate;
143}
144
145/************************** sysfs interface ************************/
146
147static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set,
148 const char *buf, size_t count)
149{
150 struct dbs_data *dbs_data = to_dbs_data(attr_set);
151 unsigned int input;
152 int ret;
153 ret = sscanf(buf, "%u", &input);
154
155 if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
156 return -EINVAL;
157
158 dbs_data->sampling_down_factor = input;
159 return count;
160}
161
162static ssize_t store_up_threshold(struct gov_attr_set *attr_set,
163 const char *buf, size_t count)
164{
165 struct dbs_data *dbs_data = to_dbs_data(attr_set);
166 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
167 unsigned int input;
168 int ret;
169 ret = sscanf(buf, "%u", &input);
170
171 if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold)
172 return -EINVAL;
173
174 dbs_data->up_threshold = input;
175 return count;
176}
177
178static ssize_t store_down_threshold(struct gov_attr_set *attr_set,
179 const char *buf, size_t count)
180{
181 struct dbs_data *dbs_data = to_dbs_data(attr_set);
182 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
183 unsigned int input;
184 int ret;
185 ret = sscanf(buf, "%u", &input);
186
187 /* cannot be lower than 1 otherwise freq will not fall */
188 if (ret != 1 || input < 1 || input > 100 ||
189 input >= dbs_data->up_threshold)
190 return -EINVAL;
191
192 cs_tuners->down_threshold = input;
193 return count;
194}
195
196static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set,
197 const char *buf, size_t count)
198{
199 struct dbs_data *dbs_data = to_dbs_data(attr_set);
200 unsigned int input;
201 int ret;
202
203 ret = sscanf(buf, "%u", &input);
204 if (ret != 1)
205 return -EINVAL;
206
207 if (input > 1)
208 input = 1;
209
210 if (input == dbs_data->ignore_nice_load) /* nothing to do */
211 return count;
212
213 dbs_data->ignore_nice_load = input;
214
215 /* we need to re-evaluate prev_cpu_idle */
216 gov_update_cpu_data(dbs_data);
217
218 return count;
219}
220
221static ssize_t store_freq_step(struct gov_attr_set *attr_set, const char *buf,
222 size_t count)
223{
224 struct dbs_data *dbs_data = to_dbs_data(attr_set);
225 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
226 unsigned int input;
227 int ret;
228 ret = sscanf(buf, "%u", &input);
229
230 if (ret != 1)
231 return -EINVAL;
232
233 if (input > 100)
234 input = 100;
235
236 /*
237 * no need to test here if freq_step is zero as the user might actually
238 * want this, they would be crazy though :)
239 */
240 cs_tuners->freq_step = input;
241 return count;
242}
243
244gov_show_one_common(sampling_rate);
245gov_show_one_common(sampling_down_factor);
246gov_show_one_common(up_threshold);
247gov_show_one_common(ignore_nice_load);
248gov_show_one(cs, down_threshold);
249gov_show_one(cs, freq_step);
250
251gov_attr_rw(sampling_rate);
252gov_attr_rw(sampling_down_factor);
253gov_attr_rw(up_threshold);
254gov_attr_rw(ignore_nice_load);
255gov_attr_rw(down_threshold);
256gov_attr_rw(freq_step);
257
258static struct attribute *cs_attributes[] = {
259 &sampling_rate.attr,
260 &sampling_down_factor.attr,
261 &up_threshold.attr,
262 &down_threshold.attr,
263 &ignore_nice_load.attr,
264 &freq_step.attr,
265 NULL
266};
267
268/************************** sysfs end ************************/
269
270static struct policy_dbs_info *cs_alloc(void)
271{
272 struct cs_policy_dbs_info *dbs_info;
273
274 dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL);
275 return dbs_info ? &dbs_info->policy_dbs : NULL;
276}
277
278static void cs_free(struct policy_dbs_info *policy_dbs)
279{
280 kfree(to_dbs_info(policy_dbs));
281}
282
283static int cs_init(struct dbs_data *dbs_data)
284{
285 struct cs_dbs_tuners *tuners;
286
287 tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
288 if (!tuners)
289 return -ENOMEM;
290
291 tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
292 tuners->freq_step = DEF_FREQUENCY_STEP;
293 dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
294 dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
295 dbs_data->ignore_nice_load = 0;
296 dbs_data->tuners = tuners;
297
298 return 0;
299}
300
301static void cs_exit(struct dbs_data *dbs_data)
302{
303 kfree(dbs_data->tuners);
304}
305
306static void cs_start(struct cpufreq_policy *policy)
307{
308 struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data);
309
310 dbs_info->down_skip = 0;
311 dbs_info->requested_freq = policy->cur;
312}
313
314static struct dbs_governor cs_governor = {
315 .gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"),
316 .kobj_type = { .default_attrs = cs_attributes },
317 .gov_dbs_update = cs_dbs_update,
318 .alloc = cs_alloc,
319 .free = cs_free,
320 .init = cs_init,
321 .exit = cs_exit,
322 .start = cs_start,
323};
324
325#define CPU_FREQ_GOV_CONSERVATIVE (cs_governor.gov)
326
327MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
328MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
329 "Low Latency Frequency Transition capable processors "
330 "optimised for use in a battery environment");
331MODULE_LICENSE("GPL");
332
333#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
334struct cpufreq_governor *cpufreq_default_governor(void)
335{
336 return &CPU_FREQ_GOV_CONSERVATIVE;
337}
338#endif
339
340cpufreq_governor_init(CPU_FREQ_GOV_CONSERVATIVE);
341cpufreq_governor_exit(CPU_FREQ_GOV_CONSERVATIVE);