1/*
2 *  drivers/cpufreq/cpufreq_stats.c
3 *
4 *  Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
5 *  (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/kernel.h>
13#include <linux/slab.h>
14#include <linux/cpu.h>
15#include <linux/sysfs.h>
16#include <linux/cpufreq.h>
17#include <linux/module.h>
18#include <linux/jiffies.h>
19#include <linux/percpu.h>
20#include <linux/kobject.h>
21#include <linux/spinlock.h>
22#include <linux/notifier.h>
23#include <asm/cputime.h>
24
25static spinlock_t cpufreq_stats_lock;
26
27#define CPUFREQ_STATDEVICE_ATTR(_name, _mode, _show) \
28static struct freq_attr _attr_##_name = {\
29	.attr = {.name = __stringify(_name), .mode = _mode, }, \
30	.show = _show,\
31};
32
33struct cpufreq_stats {
34	unsigned int cpu;
35	unsigned int total_trans;
36	unsigned long long  last_time;
37	unsigned int max_state;
38	unsigned int state_num;
39	unsigned int last_index;
40	cputime64_t *time_in_state;
41	unsigned int *freq_table;
42#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
43	unsigned int *trans_table;
44#endif
45};
46
47static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
48
49struct cpufreq_stats_attribute {
50	struct attribute attr;
51	ssize_t(*show) (struct cpufreq_stats *, char *);
52};
53
54static int cpufreq_stats_update(unsigned int cpu)
55{
56	struct cpufreq_stats *stat;
57	unsigned long long cur_time;
58
59	cur_time = get_jiffies_64();
60	spin_lock(&cpufreq_stats_lock);
61	stat = per_cpu(cpufreq_stats_table, cpu);
62	if (stat->time_in_state)
63		stat->time_in_state[stat->last_index] +=
64			cur_time - stat->last_time;
65	stat->last_time = cur_time;
66	spin_unlock(&cpufreq_stats_lock);
67	return 0;
68}
69
70static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
71{
72	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
73	if (!stat)
74		return 0;
75	return sprintf(buf, "%d\n",
76			per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
77}
78
79static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
80{
81	ssize_t len = 0;
82	int i;
83	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
84	if (!stat)
85		return 0;
86	cpufreq_stats_update(stat->cpu);
87	for (i = 0; i < stat->state_num; i++) {
88		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
89			(unsigned long long)
90			cputime64_to_clock_t(stat->time_in_state[i]));
91	}
92	return len;
93}
94
95#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
96static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
97{
98	ssize_t len = 0;
99	int i, j;
100
101	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
102	if (!stat)
103		return 0;
104	cpufreq_stats_update(stat->cpu);
105	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
106	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
107	for (i = 0; i < stat->state_num; i++) {
108		if (len >= PAGE_SIZE)
109			break;
110		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
111				stat->freq_table[i]);
112	}
113	if (len >= PAGE_SIZE)
114		return PAGE_SIZE;
115
116	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
117
118	for (i = 0; i < stat->state_num; i++) {
119		if (len >= PAGE_SIZE)
120			break;
121
122		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
123				stat->freq_table[i]);
124
125		for (j = 0; j < stat->state_num; j++)   {
126			if (len >= PAGE_SIZE)
127				break;
128			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
129					stat->trans_table[i*stat->max_state+j]);
130		}
131		if (len >= PAGE_SIZE)
132			break;
133		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
134	}
135	if (len >= PAGE_SIZE)
136		return PAGE_SIZE;
137	return len;
138}
139CPUFREQ_STATDEVICE_ATTR(trans_table, 0444, show_trans_table);
140#endif
141
142CPUFREQ_STATDEVICE_ATTR(total_trans, 0444, show_total_trans);
143CPUFREQ_STATDEVICE_ATTR(time_in_state, 0444, show_time_in_state);
144
145static struct attribute *default_attrs[] = {
146	&_attr_total_trans.attr,
147	&_attr_time_in_state.attr,
148#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
149	&_attr_trans_table.attr,
150#endif
151	NULL
152};
153static struct attribute_group stats_attr_group = {
154	.attrs = default_attrs,
155	.name = "stats"
156};
157
158static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
159{
160	int index;
161	for (index = 0; index < stat->max_state; index++)
162		if (stat->freq_table[index] == freq)
163			return index;
164	return -1;
165}
166
167/* should be called late in the CPU removal sequence so that the stats
168 * memory is still available in case someone tries to use it.
169 */
170static void cpufreq_stats_free_table(unsigned int cpu)
171{
172	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
173	if (stat) {
174		kfree(stat->time_in_state);
175		kfree(stat);
176	}
177	per_cpu(cpufreq_stats_table, cpu) = NULL;
178}
179
180/* must be called early in the CPU removal sequence (before
181 * cpufreq_remove_dev) so that policy is still valid.
182 */
183static void cpufreq_stats_free_sysfs(unsigned int cpu)
184{
185	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
186	if (policy && policy->cpu == cpu)
187		sysfs_remove_group(&policy->kobj, &stats_attr_group);
188	if (policy)
189		cpufreq_cpu_put(policy);
190}
191
192static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
193		struct cpufreq_frequency_table *table)
194{
195	unsigned int i, j, count = 0, ret = 0;
196	struct cpufreq_stats *stat;
197	struct cpufreq_policy *data;
198	unsigned int alloc_size;
199	unsigned int cpu = policy->cpu;
200	if (per_cpu(cpufreq_stats_table, cpu))
201		return -EBUSY;
202	stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
203	if ((stat) == NULL)
204		return -ENOMEM;
205
206	data = cpufreq_cpu_get(cpu);
207	if (data == NULL) {
208		ret = -EINVAL;
209		goto error_get_fail;
210	}
211
212	ret = sysfs_create_group(&data->kobj, &stats_attr_group);
213	if (ret)
214		goto error_out;
215
216	stat->cpu = cpu;
217	per_cpu(cpufreq_stats_table, cpu) = stat;
218
219	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
220		unsigned int freq = table[i].frequency;
221		if (freq == CPUFREQ_ENTRY_INVALID)
222			continue;
223		count++;
224	}
225
226	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
227
228#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
229	alloc_size += count * count * sizeof(int);
230#endif
231	stat->max_state = count;
232	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
233	if (!stat->time_in_state) {
234		ret = -ENOMEM;
235		goto error_out;
236	}
237	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
238
239#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
240	stat->trans_table = stat->freq_table + count;
241#endif
242	j = 0;
243	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
244		unsigned int freq = table[i].frequency;
245		if (freq == CPUFREQ_ENTRY_INVALID)
246			continue;
247		if (freq_table_get_index(stat, freq) == -1)
248			stat->freq_table[j++] = freq;
249	}
250	stat->state_num = j;
251	spin_lock(&cpufreq_stats_lock);
252	stat->last_time = get_jiffies_64();
253	stat->last_index = freq_table_get_index(stat, policy->cur);
254	spin_unlock(&cpufreq_stats_lock);
255	cpufreq_cpu_put(data);
256	return 0;
257error_out:
258	cpufreq_cpu_put(data);
259error_get_fail:
260	kfree(stat);
261	per_cpu(cpufreq_stats_table, cpu) = NULL;
262	return ret;
263}
264
265static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
266		unsigned long val, void *data)
267{
268	int ret;
269	struct cpufreq_policy *policy = data;
270	struct cpufreq_frequency_table *table;
271	unsigned int cpu = policy->cpu;
272	if (val != CPUFREQ_NOTIFY)
273		return 0;
274	table = cpufreq_frequency_get_table(cpu);
275	if (!table)
276		return 0;
277	ret = cpufreq_stats_create_table(policy, table);
278	if (ret)
279		return ret;
280	return 0;
281}
282
283static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
284		unsigned long val, void *data)
285{
286	struct cpufreq_freqs *freq = data;
287	struct cpufreq_stats *stat;
288	int old_index, new_index;
289
290	if (val != CPUFREQ_POSTCHANGE)
291		return 0;
292
293	stat = per_cpu(cpufreq_stats_table, freq->cpu);
294	if (!stat)
295		return 0;
296
297	old_index = stat->last_index;
298	new_index = freq_table_get_index(stat, freq->new);
299
300	/* We can't do stat->time_in_state[-1]= .. */
301	if (old_index == -1 || new_index == -1)
302		return 0;
303
304	cpufreq_stats_update(freq->cpu);
305
306	if (old_index == new_index)
307		return 0;
308
309	spin_lock(&cpufreq_stats_lock);
310	stat->last_index = new_index;
311#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
312	stat->trans_table[old_index * stat->max_state + new_index]++;
313#endif
314	stat->total_trans++;
315	spin_unlock(&cpufreq_stats_lock);
316	return 0;
317}
318
319static int cpufreq_stats_create_table_cpu(unsigned int cpu)
320{
321	struct cpufreq_policy *policy;
322	struct cpufreq_frequency_table *table;
323	int ret = -ENODEV;
324
325	policy = cpufreq_cpu_get(cpu);
326	if (!policy)
327		return -ENODEV;
328
329	table = cpufreq_frequency_get_table(cpu);
330	if (!table)
331		goto out;
332
333	ret = cpufreq_stats_create_table(policy, table);
334
335out:
336	cpufreq_cpu_put(policy);
337	return ret;
338}
339
340static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
341					       unsigned long action,
342					       void *hcpu)
343{
344	unsigned int cpu = (unsigned long)hcpu;
345
346	switch (action) {
347	case CPU_ONLINE:
348	case CPU_ONLINE_FROZEN:
349		cpufreq_update_policy(cpu);
350		break;
351	case CPU_DOWN_PREPARE:
352		cpufreq_stats_free_sysfs(cpu);
353		break;
354	case CPU_DEAD:
355	case CPU_DEAD_FROZEN:
356		cpufreq_stats_free_table(cpu);
357		break;
358	case CPU_DOWN_FAILED:
359	case CPU_DOWN_FAILED_FROZEN:
360		cpufreq_stats_create_table_cpu(cpu);
361		break;
362	}
363	return NOTIFY_OK;
364}
365
366/* priority=1 so this will get called before cpufreq_remove_dev */
367static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
368	.notifier_call = cpufreq_stat_cpu_callback,
369	.priority = 1,
370};
371
372static struct notifier_block notifier_policy_block = {
373	.notifier_call = cpufreq_stat_notifier_policy
374};
375
376static struct notifier_block notifier_trans_block = {
377	.notifier_call = cpufreq_stat_notifier_trans
378};
379
380static int __init cpufreq_stats_init(void)
381{
382	int ret;
383	unsigned int cpu;
384
385	spin_lock_init(&cpufreq_stats_lock);
386	ret = cpufreq_register_notifier(&notifier_policy_block,
387				CPUFREQ_POLICY_NOTIFIER);
388	if (ret)
389		return ret;
390
391	ret = cpufreq_register_notifier(&notifier_trans_block,
392				CPUFREQ_TRANSITION_NOTIFIER);
393	if (ret) {
394		cpufreq_unregister_notifier(&notifier_policy_block,
395				CPUFREQ_POLICY_NOTIFIER);
396		return ret;
397	}
398
399	register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
400	for_each_online_cpu(cpu) {
401		cpufreq_update_policy(cpu);
402	}
403	return 0;
404}
405static void __exit cpufreq_stats_exit(void)
406{
407	unsigned int cpu;
408
409	cpufreq_unregister_notifier(&notifier_policy_block,
410			CPUFREQ_POLICY_NOTIFIER);
411	cpufreq_unregister_notifier(&notifier_trans_block,
412			CPUFREQ_TRANSITION_NOTIFIER);
413	unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
414	for_each_online_cpu(cpu) {
415		cpufreq_stats_free_table(cpu);
416		cpufreq_stats_free_sysfs(cpu);
417	}
418}
419
420MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
421MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
422				"through sysfs filesystem");
423MODULE_LICENSE("GPL");
424
425module_init(cpufreq_stats_init);
426module_exit(cpufreq_stats_exit);
427