cpufreq: OMAP: put clk if cpu_init failed
[linux-2.6.git] / drivers / cpufreq / cpufreq_conservative.c
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/kernel.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/cpufreq.h>
18 #include <linux/cpu.h>
19 #include <linux/jiffies.h>
20 #include <linux/kernel_stat.h>
21 #include <linux/mutex.h>
22 #include <linux/hrtimer.h>
23 #include <linux/tick.h>
24 #include <linux/ktime.h>
25 #include <linux/sched.h>
26
27 /*
28  * dbs is used in this file as a shortform for demandbased switching
29  * It helps to keep variable names smaller, simpler
30  */
31
32 #define DEF_FREQUENCY_UP_THRESHOLD              (80)
33 #define DEF_FREQUENCY_DOWN_THRESHOLD            (20)
34
35 /*
36  * The polling frequency of this governor depends on the capability of
37  * the processor. Default polling frequency is 1000 times the transition
38  * latency of the processor. The governor will work on any processor with
39  * transition latency <= 10mS, using appropriate sampling
40  * rate.
41  * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
42  * this governor will not work.
43  * All times here are in uS.
44  */
45 #define MIN_SAMPLING_RATE_RATIO                 (2)
46
47 static unsigned int min_sampling_rate;
48
49 #define LATENCY_MULTIPLIER                      (1000)
50 #define MIN_LATENCY_MULTIPLIER                  (100)
51 #define DEF_SAMPLING_DOWN_FACTOR                (1)
52 #define MAX_SAMPLING_DOWN_FACTOR                (10)
53 #define TRANSITION_LATENCY_LIMIT                (10 * 1000 * 1000)
54
55 static void do_dbs_timer(struct work_struct *work);
56
57 struct cpu_dbs_info_s {
58         cputime64_t prev_cpu_idle;
59         cputime64_t prev_cpu_wall;
60         cputime64_t prev_cpu_nice;
61         struct cpufreq_policy *cur_policy;
62         struct delayed_work work;
63         unsigned int down_skip;
64         unsigned int requested_freq;
65         int cpu;
66         unsigned int enable:1;
67         /*
68          * percpu mutex that serializes governor limit change with
69          * do_dbs_timer invocation. We do not want do_dbs_timer to run
70          * when user is changing the governor or limits.
71          */
72         struct mutex timer_mutex;
73 };
74 static DEFINE_PER_CPU(struct cpu_dbs_info_s, cs_cpu_dbs_info);
75
76 static unsigned int dbs_enable; /* number of CPUs using this policy */
77
78 /*
79  * dbs_mutex protects dbs_enable in governor start/stop.
80  */
81 static DEFINE_MUTEX(dbs_mutex);
82
83 static struct dbs_tuners {
84         unsigned int sampling_rate;
85         unsigned int sampling_down_factor;
86         unsigned int up_threshold;
87         unsigned int down_threshold;
88         unsigned int ignore_nice;
89         unsigned int freq_step;
90 } dbs_tuners_ins = {
91         .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
92         .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD,
93         .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
94         .ignore_nice = 0,
95         .freq_step = 5,
96 };
97
98 static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
99                                                         cputime64_t *wall)
100 {
101         cputime64_t idle_time;
102         cputime64_t cur_wall_time;
103         cputime64_t busy_time;
104
105         cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
106         busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user,
107                         kstat_cpu(cpu).cpustat.system);
108
109         busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq);
110         busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq);
111         busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal);
112         busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice);
113
114         idle_time = cputime64_sub(cur_wall_time, busy_time);
115         if (wall)
116                 *wall = (cputime64_t)jiffies_to_usecs(cur_wall_time);
117
118         return (cputime64_t)jiffies_to_usecs(idle_time);
119 }
120
121 static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
122 {
123         u64 idle_time = get_cpu_idle_time_us(cpu, NULL);
124
125         if (idle_time == -1ULL)
126                 return get_cpu_idle_time_jiffy(cpu, wall);
127         else
128                 idle_time += get_cpu_iowait_time_us(cpu, wall);
129
130         return idle_time;
131 }
132
133 /* keep track of frequency transitions */
134 static int
135 dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
136                      void *data)
137 {
138         struct cpufreq_freqs *freq = data;
139         struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cs_cpu_dbs_info,
140                                                         freq->cpu);
141
142         struct cpufreq_policy *policy;
143
144         if (!this_dbs_info->enable)
145                 return 0;
146
147         policy = this_dbs_info->cur_policy;
148
149         /*
150          * we only care if our internally tracked freq moves outside
151          * the 'valid' ranges of freqency available to us otherwise
152          * we do not change it
153         */
154         if (this_dbs_info->requested_freq > policy->max
155                         || this_dbs_info->requested_freq < policy->min)
156                 this_dbs_info->requested_freq = freq->new;
157
158         return 0;
159 }
160
161 static struct notifier_block dbs_cpufreq_notifier_block = {
162         .notifier_call = dbs_cpufreq_notifier
163 };
164
165 /************************** sysfs interface ************************/
166 static ssize_t show_sampling_rate_min(struct kobject *kobj,
167                                       struct attribute *attr, char *buf)
168 {
169         return sprintf(buf, "%u\n", min_sampling_rate);
170 }
171
172 define_one_global_ro(sampling_rate_min);
173
174 /* cpufreq_conservative Governor Tunables */
175 #define show_one(file_name, object)                                     \
176 static ssize_t show_##file_name                                         \
177 (struct kobject *kobj, struct attribute *attr, char *buf)               \
178 {                                                                       \
179         return sprintf(buf, "%u\n", dbs_tuners_ins.object);             \
180 }
181 show_one(sampling_rate, sampling_rate);
182 show_one(sampling_down_factor, sampling_down_factor);
183 show_one(up_threshold, up_threshold);
184 show_one(down_threshold, down_threshold);
185 show_one(ignore_nice_load, ignore_nice);
186 show_one(freq_step, freq_step);
187
188 static ssize_t store_sampling_down_factor(struct kobject *a,
189                                           struct attribute *b,
190                                           const char *buf, size_t count)
191 {
192         unsigned int input;
193         int ret;
194         ret = sscanf(buf, "%u", &input);
195
196         if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
197                 return -EINVAL;
198
199         dbs_tuners_ins.sampling_down_factor = input;
200         return count;
201 }
202
203 static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
204                                    const char *buf, size_t count)
205 {
206         unsigned int input;
207         int ret;
208         ret = sscanf(buf, "%u", &input);
209
210         if (ret != 1)
211                 return -EINVAL;
212
213         dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate);
214         return count;
215 }
216
217 static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
218                                   const char *buf, size_t count)
219 {
220         unsigned int input;
221         int ret;
222         ret = sscanf(buf, "%u", &input);
223
224         if (ret != 1 || input > 100 ||
225                         input <= dbs_tuners_ins.down_threshold)
226                 return -EINVAL;
227
228         dbs_tuners_ins.up_threshold = input;
229         return count;
230 }
231
232 static ssize_t store_down_threshold(struct kobject *a, struct attribute *b,
233                                     const char *buf, size_t count)
234 {
235         unsigned int input;
236         int ret;
237         ret = sscanf(buf, "%u", &input);
238
239         /* cannot be lower than 11 otherwise freq will not fall */
240         if (ret != 1 || input < 11 || input > 100 ||
241                         input >= dbs_tuners_ins.up_threshold)
242                 return -EINVAL;
243
244         dbs_tuners_ins.down_threshold = input;
245         return count;
246 }
247
248 static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
249                                       const char *buf, size_t count)
250 {
251         unsigned int input;
252         int ret;
253
254         unsigned int j;
255
256         ret = sscanf(buf, "%u", &input);
257         if (ret != 1)
258                 return -EINVAL;
259
260         if (input > 1)
261                 input = 1;
262
263         if (input == dbs_tuners_ins.ignore_nice) /* nothing to do */
264                 return count;
265
266         dbs_tuners_ins.ignore_nice = input;
267
268         /* we need to re-evaluate prev_cpu_idle */
269         for_each_online_cpu(j) {
270                 struct cpu_dbs_info_s *dbs_info;
271                 dbs_info = &per_cpu(cs_cpu_dbs_info, j);
272                 dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
273                                                 &dbs_info->prev_cpu_wall);
274                 if (dbs_tuners_ins.ignore_nice)
275                         dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
276         }
277         return count;
278 }
279
280 static ssize_t store_freq_step(struct kobject *a, struct attribute *b,
281                                const char *buf, size_t count)
282 {
283         unsigned int input;
284         int ret;
285         ret = sscanf(buf, "%u", &input);
286
287         if (ret != 1)
288                 return -EINVAL;
289
290         if (input > 100)
291                 input = 100;
292
293         /* no need to test here if freq_step is zero as the user might actually
294          * want this, they would be crazy though :) */
295         dbs_tuners_ins.freq_step = input;
296         return count;
297 }
298
299 define_one_global_rw(sampling_rate);
300 define_one_global_rw(sampling_down_factor);
301 define_one_global_rw(up_threshold);
302 define_one_global_rw(down_threshold);
303 define_one_global_rw(ignore_nice_load);
304 define_one_global_rw(freq_step);
305
306 static struct attribute *dbs_attributes[] = {
307         &sampling_rate_min.attr,
308         &sampling_rate.attr,
309         &sampling_down_factor.attr,
310         &up_threshold.attr,
311         &down_threshold.attr,
312         &ignore_nice_load.attr,
313         &freq_step.attr,
314         NULL
315 };
316
317 static struct attribute_group dbs_attr_group = {
318         .attrs = dbs_attributes,
319         .name = "conservative",
320 };
321
322 /************************** sysfs end ************************/
323
324 static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
325 {
326         unsigned int load = 0;
327         unsigned int max_load = 0;
328         unsigned int freq_target;
329
330         struct cpufreq_policy *policy;
331         unsigned int j;
332
333         policy = this_dbs_info->cur_policy;
334
335         /*
336          * Every sampling_rate, we check, if current idle time is less
337          * than 20% (default), then we try to increase frequency
338          * Every sampling_rate*sampling_down_factor, we check, if current
339          * idle time is more than 80%, then we try to decrease frequency
340          *
341          * Any frequency increase takes it to the maximum frequency.
342          * Frequency reduction happens at minimum steps of
343          * 5% (default) of maximum frequency
344          */
345
346         /* Get Absolute Load */
347         for_each_cpu(j, policy->cpus) {
348                 struct cpu_dbs_info_s *j_dbs_info;
349                 cputime64_t cur_wall_time, cur_idle_time;
350                 unsigned int idle_time, wall_time;
351
352                 j_dbs_info = &per_cpu(cs_cpu_dbs_info, j);
353
354                 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
355
356                 wall_time = (unsigned int) cputime64_sub(cur_wall_time,
357                                 j_dbs_info->prev_cpu_wall);
358                 j_dbs_info->prev_cpu_wall = cur_wall_time;
359
360                 idle_time = (unsigned int) cputime64_sub(cur_idle_time,
361                                 j_dbs_info->prev_cpu_idle);
362                 j_dbs_info->prev_cpu_idle = cur_idle_time;
363
364                 if (dbs_tuners_ins.ignore_nice) {
365                         cputime64_t cur_nice;
366                         unsigned long cur_nice_jiffies;
367
368                         cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice,
369                                          j_dbs_info->prev_cpu_nice);
370                         /*
371                          * Assumption: nice time between sampling periods will
372                          * be less than 2^32 jiffies for 32 bit sys
373                          */
374                         cur_nice_jiffies = (unsigned long)
375                                         cputime64_to_jiffies64(cur_nice);
376
377                         j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
378                         idle_time += jiffies_to_usecs(cur_nice_jiffies);
379                 }
380
381                 if (unlikely(!wall_time || wall_time < idle_time))
382                         continue;
383
384                 load = 100 * (wall_time - idle_time) / wall_time;
385
386                 if (load > max_load)
387                         max_load = load;
388         }
389
390         /*
391          * break out if we 'cannot' reduce the speed as the user might
392          * want freq_step to be zero
393          */
394         if (dbs_tuners_ins.freq_step == 0)
395                 return;
396
397         /* Check for frequency increase */
398         if (max_load > dbs_tuners_ins.up_threshold) {
399                 this_dbs_info->down_skip = 0;
400
401                 /* if we are already at full speed then break out early */
402                 if (this_dbs_info->requested_freq == policy->max)
403                         return;
404
405                 freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100;
406
407                 /* max freq cannot be less than 100. But who knows.... */
408                 if (unlikely(freq_target == 0))
409                         freq_target = 5;
410
411                 this_dbs_info->requested_freq += freq_target;
412                 if (this_dbs_info->requested_freq > policy->max)
413                         this_dbs_info->requested_freq = policy->max;
414
415                 __cpufreq_driver_target(policy, this_dbs_info->requested_freq,
416                         CPUFREQ_RELATION_H);
417                 return;
418         }
419
420         /*
421          * The optimal frequency is the frequency that is the lowest that
422          * can support the current CPU usage without triggering the up
423          * policy. To be safe, we focus 10 points under the threshold.
424          */
425         if (max_load < (dbs_tuners_ins.down_threshold - 10)) {
426                 freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100;
427
428                 this_dbs_info->requested_freq -= freq_target;
429                 if (this_dbs_info->requested_freq < policy->min)
430                         this_dbs_info->requested_freq = policy->min;
431
432                 /*
433                  * if we cannot reduce the frequency anymore, break out early
434                  */
435                 if (policy->cur == policy->min)
436                         return;
437
438                 __cpufreq_driver_target(policy, this_dbs_info->requested_freq,
439                                 CPUFREQ_RELATION_H);
440                 return;
441         }
442 }
443
444 static void do_dbs_timer(struct work_struct *work)
445 {
446         struct cpu_dbs_info_s *dbs_info =
447                 container_of(work, struct cpu_dbs_info_s, work.work);
448         unsigned int cpu = dbs_info->cpu;
449
450         /* We want all CPUs to do sampling nearly on same jiffy */
451         int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
452
453         delay -= jiffies % delay;
454
455         mutex_lock(&dbs_info->timer_mutex);
456
457         dbs_check_cpu(dbs_info);
458
459         schedule_delayed_work_on(cpu, &dbs_info->work, delay);
460         mutex_unlock(&dbs_info->timer_mutex);
461 }
462
463 static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
464 {
465         /* We want all CPUs to do sampling nearly on same jiffy */
466         int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
467         delay -= jiffies % delay;
468
469         dbs_info->enable = 1;
470         INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
471         schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, delay);
472 }
473
474 static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
475 {
476         dbs_info->enable = 0;
477         cancel_delayed_work_sync(&dbs_info->work);
478 }
479
480 static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
481                                    unsigned int event)
482 {
483         unsigned int cpu = policy->cpu;
484         struct cpu_dbs_info_s *this_dbs_info;
485         unsigned int j;
486         int rc;
487
488         this_dbs_info = &per_cpu(cs_cpu_dbs_info, cpu);
489
490         switch (event) {
491         case CPUFREQ_GOV_START:
492                 if ((!cpu_online(cpu)) || (!policy->cur))
493                         return -EINVAL;
494
495                 mutex_lock(&dbs_mutex);
496
497                 for_each_cpu(j, policy->cpus) {
498                         struct cpu_dbs_info_s *j_dbs_info;
499                         j_dbs_info = &per_cpu(cs_cpu_dbs_info, j);
500                         j_dbs_info->cur_policy = policy;
501
502                         j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
503                                                 &j_dbs_info->prev_cpu_wall);
504                         if (dbs_tuners_ins.ignore_nice) {
505                                 j_dbs_info->prev_cpu_nice =
506                                                 kstat_cpu(j).cpustat.nice;
507                         }
508                 }
509                 this_dbs_info->down_skip = 0;
510                 this_dbs_info->requested_freq = policy->cur;
511
512                 mutex_init(&this_dbs_info->timer_mutex);
513                 dbs_enable++;
514                 /*
515                  * Start the timerschedule work, when this governor
516                  * is used for first time
517                  */
518                 if (dbs_enable == 1) {
519                         unsigned int latency;
520                         /* policy latency is in nS. Convert it to uS first */
521                         latency = policy->cpuinfo.transition_latency / 1000;
522                         if (latency == 0)
523                                 latency = 1;
524
525                         rc = sysfs_create_group(cpufreq_global_kobject,
526                                                 &dbs_attr_group);
527                         if (rc) {
528                                 mutex_unlock(&dbs_mutex);
529                                 return rc;
530                         }
531
532                         /*
533                          * conservative does not implement micro like ondemand
534                          * governor, thus we are bound to jiffes/HZ
535                          */
536                         min_sampling_rate =
537                                 MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10);
538                         /* Bring kernel and HW constraints together */
539                         min_sampling_rate = max(min_sampling_rate,
540                                         MIN_LATENCY_MULTIPLIER * latency);
541                         dbs_tuners_ins.sampling_rate =
542                                 max(min_sampling_rate,
543                                     latency * LATENCY_MULTIPLIER);
544
545                         cpufreq_register_notifier(
546                                         &dbs_cpufreq_notifier_block,
547                                         CPUFREQ_TRANSITION_NOTIFIER);
548                 }
549                 mutex_unlock(&dbs_mutex);
550
551                 dbs_timer_init(this_dbs_info);
552
553                 break;
554
555         case CPUFREQ_GOV_STOP:
556                 dbs_timer_exit(this_dbs_info);
557
558                 mutex_lock(&dbs_mutex);
559                 dbs_enable--;
560                 mutex_destroy(&this_dbs_info->timer_mutex);
561
562                 /*
563                  * Stop the timerschedule work, when this governor
564                  * is used for first time
565                  */
566                 if (dbs_enable == 0)
567                         cpufreq_unregister_notifier(
568                                         &dbs_cpufreq_notifier_block,
569                                         CPUFREQ_TRANSITION_NOTIFIER);
570
571                 mutex_unlock(&dbs_mutex);
572                 if (!dbs_enable)
573                         sysfs_remove_group(cpufreq_global_kobject,
574                                            &dbs_attr_group);
575
576                 break;
577
578         case CPUFREQ_GOV_LIMITS:
579                 mutex_lock(&this_dbs_info->timer_mutex);
580                 if (policy->max < this_dbs_info->cur_policy->cur)
581                         __cpufreq_driver_target(
582                                         this_dbs_info->cur_policy,
583                                         policy->max, CPUFREQ_RELATION_H);
584                 else if (policy->min > this_dbs_info->cur_policy->cur)
585                         __cpufreq_driver_target(
586                                         this_dbs_info->cur_policy,
587                                         policy->min, CPUFREQ_RELATION_L);
588                 mutex_unlock(&this_dbs_info->timer_mutex);
589
590                 break;
591         }
592         return 0;
593 }
594
595 #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
596 static
597 #endif
598 struct cpufreq_governor cpufreq_gov_conservative = {
599         .name                   = "conservative",
600         .governor               = cpufreq_governor_dbs,
601         .max_transition_latency = TRANSITION_LATENCY_LIMIT,
602         .owner                  = THIS_MODULE,
603 };
604
605 static int __init cpufreq_gov_dbs_init(void)
606 {
607         return cpufreq_register_governor(&cpufreq_gov_conservative);
608 }
609
610 static void __exit cpufreq_gov_dbs_exit(void)
611 {
612         cpufreq_unregister_governor(&cpufreq_gov_conservative);
613 }
614
615
616 MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
617 MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
618                 "Low Latency Frequency Transition capable processors "
619                 "optimised for use in a battery environment");
620 MODULE_LICENSE("GPL");
621
622 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
623 fs_initcall(cpufreq_gov_dbs_init);
624 #else
625 module_init(cpufreq_gov_dbs_init);
626 #endif
627 module_exit(cpufreq_gov_dbs_exit);