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Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm
[karo-tx-linux.git] / drivers / cpufreq / cpufreq_governor.c
1 /*
2  * drivers/cpufreq/cpufreq_governor.c
3  *
4  * CPUFREQ governors common code
5  *
6  * Copyright    (C) 2001 Russell King
7  *              (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
8  *              (C) 2003 Jun Nakajima <jun.nakajima@intel.com>
9  *              (C) 2009 Alexander Clouter <alex@digriz.org.uk>
10  *              (c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License version 2 as
14  * published by the Free Software Foundation.
15  */
16
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19 #include <asm/cputime.h>
20 #include <linux/cpufreq.h>
21 #include <linux/cpumask.h>
22 #include <linux/export.h>
23 #include <linux/kernel_stat.h>
24 #include <linux/mutex.h>
25 #include <linux/tick.h>
26 #include <linux/types.h>
27 #include <linux/workqueue.h>
28
29 #include "cpufreq_governor.h"
30
31 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
32 {
33         u64 idle_time;
34         u64 cur_wall_time;
35         u64 busy_time;
36
37         cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
38
39         busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
40         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
41         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
42         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
43         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
44         busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
45
46         idle_time = cur_wall_time - busy_time;
47         if (wall)
48                 *wall = cputime_to_usecs(cur_wall_time);
49
50         return cputime_to_usecs(idle_time);
51 }
52
53 u64 get_cpu_idle_time(unsigned int cpu, u64 *wall)
54 {
55         u64 idle_time = get_cpu_idle_time_us(cpu, NULL);
56
57         if (idle_time == -1ULL)
58                 return get_cpu_idle_time_jiffy(cpu, wall);
59         else
60                 idle_time += get_cpu_iowait_time_us(cpu, wall);
61
62         return idle_time;
63 }
64 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
65
66 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
67 {
68         struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);
69         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
70         struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
71         struct cpufreq_policy *policy;
72         unsigned int max_load = 0;
73         unsigned int ignore_nice;
74         unsigned int j;
75
76         if (dbs_data->governor == GOV_ONDEMAND)
77                 ignore_nice = od_tuners->ignore_nice;
78         else
79                 ignore_nice = cs_tuners->ignore_nice;
80
81         policy = cdbs->cur_policy;
82
83         /* Get Absolute Load (in terms of freq for ondemand gov) */
84         for_each_cpu(j, policy->cpus) {
85                 struct cpu_dbs_common_info *j_cdbs;
86                 u64 cur_wall_time, cur_idle_time, cur_iowait_time;
87                 unsigned int idle_time, wall_time, iowait_time;
88                 unsigned int load;
89
90                 j_cdbs = dbs_data->get_cpu_cdbs(j);
91
92                 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
93
94                 wall_time = (unsigned int)
95                         (cur_wall_time - j_cdbs->prev_cpu_wall);
96                 j_cdbs->prev_cpu_wall = cur_wall_time;
97
98                 idle_time = (unsigned int)
99                         (cur_idle_time - j_cdbs->prev_cpu_idle);
100                 j_cdbs->prev_cpu_idle = cur_idle_time;
101
102                 if (ignore_nice) {
103                         u64 cur_nice;
104                         unsigned long cur_nice_jiffies;
105
106                         cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
107                                          cdbs->prev_cpu_nice;
108                         /*
109                          * Assumption: nice time between sampling periods will
110                          * be less than 2^32 jiffies for 32 bit sys
111                          */
112                         cur_nice_jiffies = (unsigned long)
113                                         cputime64_to_jiffies64(cur_nice);
114
115                         cdbs->prev_cpu_nice =
116                                 kcpustat_cpu(j).cpustat[CPUTIME_NICE];
117                         idle_time += jiffies_to_usecs(cur_nice_jiffies);
118                 }
119
120                 if (dbs_data->governor == GOV_ONDEMAND) {
121                         struct od_cpu_dbs_info_s *od_j_dbs_info =
122                                 dbs_data->get_cpu_dbs_info_s(cpu);
123
124                         cur_iowait_time = get_cpu_iowait_time_us(j,
125                                         &cur_wall_time);
126                         if (cur_iowait_time == -1ULL)
127                                 cur_iowait_time = 0;
128
129                         iowait_time = (unsigned int) (cur_iowait_time -
130                                         od_j_dbs_info->prev_cpu_iowait);
131                         od_j_dbs_info->prev_cpu_iowait = cur_iowait_time;
132
133                         /*
134                          * For the purpose of ondemand, waiting for disk IO is
135                          * an indication that you're performance critical, and
136                          * not that the system is actually idle. So subtract the
137                          * iowait time from the cpu idle time.
138                          */
139                         if (od_tuners->io_is_busy && idle_time >= iowait_time)
140                                 idle_time -= iowait_time;
141                 }
142
143                 if (unlikely(!wall_time || wall_time < idle_time))
144                         continue;
145
146                 load = 100 * (wall_time - idle_time) / wall_time;
147
148                 if (dbs_data->governor == GOV_ONDEMAND) {
149                         int freq_avg = __cpufreq_driver_getavg(policy, j);
150                         if (freq_avg <= 0)
151                                 freq_avg = policy->cur;
152
153                         load *= freq_avg;
154                 }
155
156                 if (load > max_load)
157                         max_load = load;
158         }
159
160         dbs_data->gov_check_cpu(cpu, max_load);
161 }
162 EXPORT_SYMBOL_GPL(dbs_check_cpu);
163
164 static inline void dbs_timer_init(struct dbs_data *dbs_data, int cpu,
165                                   unsigned int sampling_rate)
166 {
167         int delay = delay_for_sampling_rate(sampling_rate);
168         struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);
169
170         schedule_delayed_work_on(cpu, &cdbs->work, delay);
171 }
172
173 static inline void dbs_timer_exit(struct dbs_data *dbs_data, int cpu)
174 {
175         struct cpu_dbs_common_info *cdbs = dbs_data->get_cpu_cdbs(cpu);
176
177         cancel_delayed_work_sync(&cdbs->work);
178 }
179
180 /* Will return if we need to evaluate cpu load again or not */
181 bool need_load_eval(struct cpu_dbs_common_info *cdbs,
182                 unsigned int sampling_rate)
183 {
184         if (policy_is_shared(cdbs->cur_policy)) {
185                 ktime_t time_now = ktime_get();
186                 s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
187
188                 /* Do nothing if we recently have sampled */
189                 if (delta_us < (s64)(sampling_rate / 2))
190                         return false;
191                 else
192                         cdbs->time_stamp = time_now;
193         }
194
195         return true;
196 }
197 EXPORT_SYMBOL_GPL(need_load_eval);
198
199 int cpufreq_governor_dbs(struct dbs_data *dbs_data,
200                 struct cpufreq_policy *policy, unsigned int event)
201 {
202         struct od_cpu_dbs_info_s *od_dbs_info = NULL;
203         struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
204         struct cs_ops *cs_ops = NULL;
205         struct od_ops *od_ops = NULL;
206         struct od_dbs_tuners *od_tuners = dbs_data->tuners;
207         struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
208         struct cpu_dbs_common_info *cpu_cdbs;
209         unsigned int *sampling_rate, latency, ignore_nice, j, cpu = policy->cpu;
210         int rc;
211
212         cpu_cdbs = dbs_data->get_cpu_cdbs(cpu);
213
214         if (dbs_data->governor == GOV_CONSERVATIVE) {
215                 cs_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
216                 sampling_rate = &cs_tuners->sampling_rate;
217                 ignore_nice = cs_tuners->ignore_nice;
218                 cs_ops = dbs_data->gov_ops;
219         } else {
220                 od_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
221                 sampling_rate = &od_tuners->sampling_rate;
222                 ignore_nice = od_tuners->ignore_nice;
223                 od_ops = dbs_data->gov_ops;
224         }
225
226         switch (event) {
227         case CPUFREQ_GOV_START:
228                 if (!policy->cur)
229                         return -EINVAL;
230
231                 mutex_lock(&dbs_data->mutex);
232
233                 for_each_cpu(j, policy->cpus) {
234                         struct cpu_dbs_common_info *j_cdbs =
235                                 dbs_data->get_cpu_cdbs(j);
236
237                         j_cdbs->cpu = j;
238                         j_cdbs->cur_policy = policy;
239                         j_cdbs->prev_cpu_idle = get_cpu_idle_time(j,
240                                         &j_cdbs->prev_cpu_wall);
241                         if (ignore_nice)
242                                 j_cdbs->prev_cpu_nice =
243                                         kcpustat_cpu(j).cpustat[CPUTIME_NICE];
244
245                         mutex_init(&j_cdbs->timer_mutex);
246                         INIT_DEFERRABLE_WORK(&j_cdbs->work,
247                                              dbs_data->gov_dbs_timer);
248                 }
249
250                 if (!policy->governor->initialized) {
251                         rc = sysfs_create_group(cpufreq_global_kobject,
252                                         dbs_data->attr_group);
253                         if (rc) {
254                                 mutex_unlock(&dbs_data->mutex);
255                                 return rc;
256                         }
257                 }
258
259                 /*
260                  * conservative does not implement micro like ondemand
261                  * governor, thus we are bound to jiffes/HZ
262                  */
263                 if (dbs_data->governor == GOV_CONSERVATIVE) {
264                         cs_dbs_info->down_skip = 0;
265                         cs_dbs_info->enable = 1;
266                         cs_dbs_info->requested_freq = policy->cur;
267
268                         if (!policy->governor->initialized) {
269                                 cpufreq_register_notifier(cs_ops->notifier_block,
270                                                 CPUFREQ_TRANSITION_NOTIFIER);
271
272                                 dbs_data->min_sampling_rate =
273                                         MIN_SAMPLING_RATE_RATIO *
274                                         jiffies_to_usecs(10);
275                         }
276                 } else {
277                         od_dbs_info->rate_mult = 1;
278                         od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
279                         od_ops->powersave_bias_init_cpu(cpu);
280
281                         if (!policy->governor->initialized)
282                                 od_tuners->io_is_busy = od_ops->io_busy();
283                 }
284
285                 if (policy->governor->initialized)
286                         goto unlock;
287
288                 /* policy latency is in nS. Convert it to uS first */
289                 latency = policy->cpuinfo.transition_latency / 1000;
290                 if (latency == 0)
291                         latency = 1;
292
293                 /* Bring kernel and HW constraints together */
294                 dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
295                                 MIN_LATENCY_MULTIPLIER * latency);
296                 *sampling_rate = max(dbs_data->min_sampling_rate, latency *
297                                 LATENCY_MULTIPLIER);
298 unlock:
299                 mutex_unlock(&dbs_data->mutex);
300
301                 /* Initiate timer time stamp */
302                 cpu_cdbs->time_stamp = ktime_get();
303
304                 for_each_cpu(j, policy->cpus)
305                         dbs_timer_init(dbs_data, j, *sampling_rate);
306                 break;
307
308         case CPUFREQ_GOV_STOP:
309                 if (dbs_data->governor == GOV_CONSERVATIVE)
310                         cs_dbs_info->enable = 0;
311
312                 for_each_cpu(j, policy->cpus)
313                         dbs_timer_exit(dbs_data, j);
314
315                 mutex_lock(&dbs_data->mutex);
316                 mutex_destroy(&cpu_cdbs->timer_mutex);
317
318                 if (policy->governor->initialized == 1) {
319                         sysfs_remove_group(cpufreq_global_kobject,
320                                         dbs_data->attr_group);
321                         if (dbs_data->governor == GOV_CONSERVATIVE)
322                                 cpufreq_unregister_notifier(cs_ops->notifier_block,
323                                                 CPUFREQ_TRANSITION_NOTIFIER);
324                 }
325                 mutex_unlock(&dbs_data->mutex);
326
327                 break;
328
329         case CPUFREQ_GOV_LIMITS:
330                 mutex_lock(&cpu_cdbs->timer_mutex);
331                 if (policy->max < cpu_cdbs->cur_policy->cur)
332                         __cpufreq_driver_target(cpu_cdbs->cur_policy,
333                                         policy->max, CPUFREQ_RELATION_H);
334                 else if (policy->min > cpu_cdbs->cur_policy->cur)
335                         __cpufreq_driver_target(cpu_cdbs->cur_policy,
336                                         policy->min, CPUFREQ_RELATION_L);
337                 dbs_check_cpu(dbs_data, cpu);
338                 mutex_unlock(&cpu_cdbs->timer_mutex);
339                 break;
340         }
341         return 0;
342 }
343 EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);