1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/drivers/devfreq/governor_passive.c
4 *
5 * Copyright (C) 2016 Samsung Electronics
6 * Author: Chanwoo Choi <cw00.choi@samsung.com>
7 * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
8 */
9
10#include <linux/module.h>
11#include <linux/cpu.h>
12#include <linux/cpufreq.h>
13#include <linux/cpumask.h>
14#include <linux/slab.h>
15#include <linux/device.h>
16#include <linux/devfreq.h>
17#include <linux/units.h>
18#include "governor.h"
19
20static struct devfreq_cpu_data *
21get_parent_cpu_data(struct devfreq_passive_data *p_data,
22 struct cpufreq_policy *policy)
23{
24 struct devfreq_cpu_data *parent_cpu_data;
25
26 if (!p_data || !policy)
27 return NULL;
28
29 list_for_each_entry(parent_cpu_data, &p_data->cpu_data_list, node)
30 if (parent_cpu_data->first_cpu == cpumask_first(srcp: policy->related_cpus))
31 return parent_cpu_data;
32
33 return NULL;
34}
35
36static void delete_parent_cpu_data(struct devfreq_passive_data *p_data)
37{
38 struct devfreq_cpu_data *parent_cpu_data, *tmp;
39
40 list_for_each_entry_safe(parent_cpu_data, tmp, &p_data->cpu_data_list, node) {
41 list_del(entry: &parent_cpu_data->node);
42
43 if (parent_cpu_data->opp_table)
44 dev_pm_opp_put_opp_table(opp_table: parent_cpu_data->opp_table);
45
46 kfree(objp: parent_cpu_data);
47 }
48}
49
50static unsigned long get_target_freq_by_required_opp(struct device *p_dev,
51 struct opp_table *p_opp_table,
52 struct opp_table *opp_table,
53 unsigned long *freq)
54{
55 struct dev_pm_opp *opp = NULL, *p_opp = NULL;
56 unsigned long target_freq;
57
58 if (!p_dev || !p_opp_table || !opp_table || !freq)
59 return 0;
60
61 p_opp = devfreq_recommended_opp(dev: p_dev, freq, flags: 0);
62 if (IS_ERR(ptr: p_opp))
63 return 0;
64
65 opp = dev_pm_opp_xlate_required_opp(src_table: p_opp_table, dst_table: opp_table, src_opp: p_opp);
66 dev_pm_opp_put(opp: p_opp);
67
68 if (IS_ERR(ptr: opp))
69 return 0;
70
71 target_freq = dev_pm_opp_get_freq(opp);
72 dev_pm_opp_put(opp);
73
74 return target_freq;
75}
76
77static int get_target_freq_with_cpufreq(struct devfreq *devfreq,
78 unsigned long *target_freq)
79{
80 struct devfreq_passive_data *p_data =
81 (struct devfreq_passive_data *)devfreq->data;
82 struct devfreq_cpu_data *parent_cpu_data;
83 struct cpufreq_policy *policy;
84 unsigned long cpu, cpu_cur, cpu_min, cpu_max, cpu_percent;
85 unsigned long dev_min, dev_max;
86 unsigned long freq = 0;
87 int ret = 0;
88
89 for_each_online_cpu(cpu) {
90 policy = cpufreq_cpu_get(cpu);
91 if (!policy) {
92 ret = -EINVAL;
93 continue;
94 }
95
96 parent_cpu_data = get_parent_cpu_data(p_data, policy);
97 if (!parent_cpu_data) {
98 cpufreq_cpu_put(policy);
99 continue;
100 }
101
102 /* Get target freq via required opps */
103 cpu_cur = parent_cpu_data->cur_freq * HZ_PER_KHZ;
104 freq = get_target_freq_by_required_opp(p_dev: parent_cpu_data->dev,
105 p_opp_table: parent_cpu_data->opp_table,
106 opp_table: devfreq->opp_table, freq: &cpu_cur);
107 if (freq) {
108 *target_freq = max(freq, *target_freq);
109 cpufreq_cpu_put(policy);
110 continue;
111 }
112
113 /* Use interpolation if required opps is not available */
114 devfreq_get_freq_range(devfreq, min_freq: &dev_min, max_freq: &dev_max);
115
116 cpu_min = parent_cpu_data->min_freq;
117 cpu_max = parent_cpu_data->max_freq;
118 cpu_cur = parent_cpu_data->cur_freq;
119
120 cpu_percent = ((cpu_cur - cpu_min) * 100) / (cpu_max - cpu_min);
121 freq = dev_min + mult_frac(dev_max - dev_min, cpu_percent, 100);
122
123 *target_freq = max(freq, *target_freq);
124 cpufreq_cpu_put(policy);
125 }
126
127 return ret;
128}
129
130static int get_target_freq_with_devfreq(struct devfreq *devfreq,
131 unsigned long *freq)
132{
133 struct devfreq_passive_data *p_data
134 = (struct devfreq_passive_data *)devfreq->data;
135 struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
136 unsigned long child_freq = ULONG_MAX;
137 int i, count;
138
139 /* Get target freq via required opps */
140 child_freq = get_target_freq_by_required_opp(p_dev: parent_devfreq->dev.parent,
141 p_opp_table: parent_devfreq->opp_table,
142 opp_table: devfreq->opp_table, freq);
143 if (child_freq)
144 goto out;
145
146 /* Use interpolation if required opps is not available */
147 for (i = 0; i < parent_devfreq->max_state; i++)
148 if (parent_devfreq->freq_table[i] == *freq)
149 break;
150
151 if (i == parent_devfreq->max_state)
152 return -EINVAL;
153
154 if (i < devfreq->max_state) {
155 child_freq = devfreq->freq_table[i];
156 } else {
157 count = devfreq->max_state;
158 child_freq = devfreq->freq_table[count - 1];
159 }
160
161out:
162 *freq = child_freq;
163
164 return 0;
165}
166
167static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
168 unsigned long *freq)
169{
170 struct devfreq_passive_data *p_data =
171 (struct devfreq_passive_data *)devfreq->data;
172 int ret;
173
174 if (!p_data)
175 return -EINVAL;
176
177 /*
178 * If the devfreq device with passive governor has the specific method
179 * to determine the next frequency, should use the get_target_freq()
180 * of struct devfreq_passive_data.
181 */
182 if (p_data->get_target_freq)
183 return p_data->get_target_freq(devfreq, freq);
184
185 switch (p_data->parent_type) {
186 case DEVFREQ_PARENT_DEV:
187 ret = get_target_freq_with_devfreq(devfreq, freq);
188 break;
189 case CPUFREQ_PARENT_DEV:
190 ret = get_target_freq_with_cpufreq(devfreq, target_freq: freq);
191 break;
192 default:
193 ret = -EINVAL;
194 dev_err(&devfreq->dev, "Invalid parent type\n");
195 break;
196 }
197
198 return ret;
199}
200
201static int cpufreq_passive_notifier_call(struct notifier_block *nb,
202 unsigned long event, void *ptr)
203{
204 struct devfreq_passive_data *p_data =
205 container_of(nb, struct devfreq_passive_data, nb);
206 struct devfreq *devfreq = (struct devfreq *)p_data->this;
207 struct devfreq_cpu_data *parent_cpu_data;
208 struct cpufreq_freqs *freqs = ptr;
209 unsigned int cur_freq;
210 int ret;
211
212 if (event != CPUFREQ_POSTCHANGE || !freqs)
213 return 0;
214
215 parent_cpu_data = get_parent_cpu_data(p_data, policy: freqs->policy);
216 if (!parent_cpu_data || parent_cpu_data->cur_freq == freqs->new)
217 return 0;
218
219 cur_freq = parent_cpu_data->cur_freq;
220 parent_cpu_data->cur_freq = freqs->new;
221
222 mutex_lock(&devfreq->lock);
223 ret = devfreq_update_target(devfreq, freq: freqs->new);
224 mutex_unlock(lock: &devfreq->lock);
225 if (ret) {
226 parent_cpu_data->cur_freq = cur_freq;
227 dev_err(&devfreq->dev, "failed to update the frequency.\n");
228 return ret;
229 }
230
231 return 0;
232}
233
234static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
235{
236 struct devfreq_passive_data *p_data
237 = (struct devfreq_passive_data *)devfreq->data;
238 int ret;
239
240 if (p_data->nb.notifier_call) {
241 ret = cpufreq_unregister_notifier(nb: &p_data->nb,
242 CPUFREQ_TRANSITION_NOTIFIER);
243 if (ret < 0)
244 return ret;
245 }
246
247 delete_parent_cpu_data(p_data);
248
249 return 0;
250}
251
252static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
253{
254 struct devfreq_passive_data *p_data
255 = (struct devfreq_passive_data *)devfreq->data;
256 struct device *dev = devfreq->dev.parent;
257 struct opp_table *opp_table = NULL;
258 struct devfreq_cpu_data *parent_cpu_data;
259 struct cpufreq_policy *policy;
260 struct device *cpu_dev;
261 unsigned int cpu;
262 int ret;
263
264 p_data->cpu_data_list
265 = (struct list_head)LIST_HEAD_INIT(p_data->cpu_data_list);
266
267 p_data->nb.notifier_call = cpufreq_passive_notifier_call;
268 ret = cpufreq_register_notifier(nb: &p_data->nb, CPUFREQ_TRANSITION_NOTIFIER);
269 if (ret) {
270 dev_err(dev, "failed to register cpufreq notifier\n");
271 p_data->nb.notifier_call = NULL;
272 goto err;
273 }
274
275 for_each_possible_cpu(cpu) {
276 policy = cpufreq_cpu_get(cpu);
277 if (!policy) {
278 ret = -EPROBE_DEFER;
279 goto err;
280 }
281
282 parent_cpu_data = get_parent_cpu_data(p_data, policy);
283 if (parent_cpu_data) {
284 cpufreq_cpu_put(policy);
285 continue;
286 }
287
288 parent_cpu_data = kzalloc(size: sizeof(*parent_cpu_data),
289 GFP_KERNEL);
290 if (!parent_cpu_data) {
291 ret = -ENOMEM;
292 goto err_put_policy;
293 }
294
295 cpu_dev = get_cpu_device(cpu);
296 if (!cpu_dev) {
297 dev_err(dev, "failed to get cpu device\n");
298 ret = -ENODEV;
299 goto err_free_cpu_data;
300 }
301
302 opp_table = dev_pm_opp_get_opp_table(dev: cpu_dev);
303 if (IS_ERR(ptr: opp_table)) {
304 dev_err(dev, "failed to get opp_table of cpu%d\n", cpu);
305 ret = PTR_ERR(ptr: opp_table);
306 goto err_free_cpu_data;
307 }
308
309 parent_cpu_data->dev = cpu_dev;
310 parent_cpu_data->opp_table = opp_table;
311 parent_cpu_data->first_cpu = cpumask_first(srcp: policy->related_cpus);
312 parent_cpu_data->cur_freq = policy->cur;
313 parent_cpu_data->min_freq = policy->cpuinfo.min_freq;
314 parent_cpu_data->max_freq = policy->cpuinfo.max_freq;
315
316 list_add_tail(new: &parent_cpu_data->node, head: &p_data->cpu_data_list);
317 cpufreq_cpu_put(policy);
318 }
319
320 mutex_lock(&devfreq->lock);
321 ret = devfreq_update_target(devfreq, freq: 0L);
322 mutex_unlock(lock: &devfreq->lock);
323 if (ret)
324 dev_err(dev, "failed to update the frequency\n");
325
326 return ret;
327
328err_free_cpu_data:
329 kfree(objp: parent_cpu_data);
330err_put_policy:
331 cpufreq_cpu_put(policy);
332err:
333
334 return ret;
335}
336
337static int devfreq_passive_notifier_call(struct notifier_block *nb,
338 unsigned long event, void *ptr)
339{
340 struct devfreq_passive_data *data
341 = container_of(nb, struct devfreq_passive_data, nb);
342 struct devfreq *devfreq = (struct devfreq *)data->this;
343 struct devfreq *parent = (struct devfreq *)data->parent;
344 struct devfreq_freqs *freqs = (struct devfreq_freqs *)ptr;
345 unsigned long freq = freqs->new;
346 int ret = 0;
347
348 mutex_lock_nested(lock: &devfreq->lock, SINGLE_DEPTH_NESTING);
349 switch (event) {
350 case DEVFREQ_PRECHANGE:
351 if (parent->previous_freq > freq)
352 ret = devfreq_update_target(devfreq, freq);
353
354 break;
355 case DEVFREQ_POSTCHANGE:
356 if (parent->previous_freq < freq)
357 ret = devfreq_update_target(devfreq, freq);
358 break;
359 }
360 mutex_unlock(lock: &devfreq->lock);
361
362 if (ret < 0)
363 dev_warn(&devfreq->dev,
364 "failed to update devfreq using passive governor\n");
365
366 return NOTIFY_DONE;
367}
368
369static int devfreq_passive_unregister_notifier(struct devfreq *devfreq)
370{
371 struct devfreq_passive_data *p_data
372 = (struct devfreq_passive_data *)devfreq->data;
373 struct devfreq *parent = (struct devfreq *)p_data->parent;
374 struct notifier_block *nb = &p_data->nb;
375
376 return devfreq_unregister_notifier(devfreq: parent, nb, DEVFREQ_TRANSITION_NOTIFIER);
377}
378
379static int devfreq_passive_register_notifier(struct devfreq *devfreq)
380{
381 struct devfreq_passive_data *p_data
382 = (struct devfreq_passive_data *)devfreq->data;
383 struct devfreq *parent = (struct devfreq *)p_data->parent;
384 struct notifier_block *nb = &p_data->nb;
385
386 if (!parent)
387 return -EPROBE_DEFER;
388
389 nb->notifier_call = devfreq_passive_notifier_call;
390 return devfreq_register_notifier(devfreq: parent, nb, DEVFREQ_TRANSITION_NOTIFIER);
391}
392
393static int devfreq_passive_event_handler(struct devfreq *devfreq,
394 unsigned int event, void *data)
395{
396 struct devfreq_passive_data *p_data
397 = (struct devfreq_passive_data *)devfreq->data;
398 int ret = 0;
399
400 if (!p_data)
401 return -EINVAL;
402
403 p_data->this = devfreq;
404
405 switch (event) {
406 case DEVFREQ_GOV_START:
407 if (p_data->parent_type == DEVFREQ_PARENT_DEV)
408 ret = devfreq_passive_register_notifier(devfreq);
409 else if (p_data->parent_type == CPUFREQ_PARENT_DEV)
410 ret = cpufreq_passive_register_notifier(devfreq);
411 break;
412 case DEVFREQ_GOV_STOP:
413 if (p_data->parent_type == DEVFREQ_PARENT_DEV)
414 WARN_ON(devfreq_passive_unregister_notifier(devfreq));
415 else if (p_data->parent_type == CPUFREQ_PARENT_DEV)
416 WARN_ON(cpufreq_passive_unregister_notifier(devfreq));
417 break;
418 default:
419 break;
420 }
421
422 return ret;
423}
424
425static struct devfreq_governor devfreq_passive = {
426 .name = DEVFREQ_GOV_PASSIVE,
427 .flags = DEVFREQ_GOV_FLAG_IMMUTABLE,
428 .get_target_freq = devfreq_passive_get_target_freq,
429 .event_handler = devfreq_passive_event_handler,
430};
431
432static int __init devfreq_passive_init(void)
433{
434 return devfreq_add_governor(governor: &devfreq_passive);
435}
436subsys_initcall(devfreq_passive_init);
437
438static void __exit devfreq_passive_exit(void)
439{
440 int ret;
441
442 ret = devfreq_remove_governor(governor: &devfreq_passive);
443 if (ret)
444 pr_err("%s: failed remove governor %d\n", __func__, ret);
445}
446module_exit(devfreq_passive_exit);
447
448MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
449MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
450MODULE_DESCRIPTION("DEVFREQ Passive governor");
451MODULE_LICENSE("GPL v2");
452

source code of linux/drivers/devfreq/governor_passive.c