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/sysdev.h>
14#include <linux/cpu.h>
15#include <linux/sysfs.h>
16#include <linux/cpufreq.h>
17#include <linux/jiffies.h>
18#include <linux/percpu.h>
19#include <linux/kobject.h>
20#include <linux/spinlock.h>
21#include <linux/notifier.h>
22#include <asm/cputime.h>
23
24static spinlock_t cpufreq_stats_lock;
25
26#define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \
27static struct freq_attr _attr_##_name = {\
28	.attr = {.name = __stringify(_name), .owner = THIS_MODULE, \
29		.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 struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];
48
49struct cpufreq_stats_attribute {
50	struct attribute attr;
51	ssize_t(*show) (struct cpufreq_stats *, char *);
52};
53
54static int
55cpufreq_stats_update (unsigned int cpu)
56{
57	struct cpufreq_stats *stat;
58	unsigned long long cur_time;
59
60	cur_time = get_jiffies_64();
61	spin_lock(&cpufreq_stats_lock);
62	stat = cpufreq_stats_table[cpu];
63	if (stat->time_in_state)
64		stat->time_in_state[stat->last_index] =
65			cputime64_add(stat->time_in_state[stat->last_index],
66				      cputime_sub(cur_time, stat->last_time));
67	stat->last_time = cur_time;
68	spin_unlock(&cpufreq_stats_lock);
69	return 0;
70}
71
72static ssize_t
73show_total_trans(struct cpufreq_policy *policy, char *buf)
74{
75	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
76	if (!stat)
77		return 0;
78	return sprintf(buf, "%d\n",
79			cpufreq_stats_table[stat->cpu]->total_trans);
80}
81
82static ssize_t
83show_time_in_state(struct cpufreq_policy *policy, char *buf)
84{
85	ssize_t len = 0;
86	int i;
87	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
88	if (!stat)
89		return 0;
90	cpufreq_stats_update(stat->cpu);
91	for (i = 0; i < stat->state_num; i++) {
92		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
93			(unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
94	}
95	return len;
96}
97
98#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
99static ssize_t
100show_trans_table(struct cpufreq_policy *policy, char *buf)
101{
102	ssize_t len = 0;
103	int i, j;
104
105	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
106	if (!stat)
107		return 0;
108	cpufreq_stats_update(stat->cpu);
109	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
110	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
111	for (i = 0; i < stat->state_num; i++) {
112		if (len >= PAGE_SIZE)
113			break;
114		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
115				stat->freq_table[i]);
116	}
117	if (len >= PAGE_SIZE)
118		return len;
119
120	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
121
122	for (i = 0; i < stat->state_num; i++) {
123		if (len >= PAGE_SIZE)
124			break;
125
126		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
127				stat->freq_table[i]);
128
129		for (j = 0; j < stat->state_num; j++)   {
130			if (len >= PAGE_SIZE)
131				break;
132			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
133					stat->trans_table[i*stat->max_state+j]);
134		}
135		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
136	}
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
159freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
160{
161	int index;
162	for (index = 0; index < stat->max_state; index++)
163		if (stat->freq_table[index] == freq)
164			return index;
165	return -1;
166}
167
168static void
169cpufreq_stats_free_table (unsigned int cpu)
170{
171	struct cpufreq_stats *stat = cpufreq_stats_table[cpu];
172	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
173	if (policy && policy->cpu == cpu)
174		sysfs_remove_group(&policy->kobj, &stats_attr_group);
175	if (stat) {
176		kfree(stat->time_in_state);
177		kfree(stat);
178	}
179	cpufreq_stats_table[cpu] = NULL;
180	if (policy)
181		cpufreq_cpu_put(policy);
182}
183
184static int
185cpufreq_stats_create_table (struct cpufreq_policy *policy,
186		struct cpufreq_frequency_table *table)
187{
188	unsigned int i, j, count = 0, ret = 0;
189	struct cpufreq_stats *stat;
190	struct cpufreq_policy *data;
191	unsigned int alloc_size;
192	unsigned int cpu = policy->cpu;
193	if (cpufreq_stats_table[cpu])
194		return -EBUSY;
195	if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
196		return -ENOMEM;
197
198	data = cpufreq_cpu_get(cpu);
199	if (data == NULL) {
200		ret = -EINVAL;
201		goto error_get_fail;
202	}
203
204	if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
205		goto error_out;
206
207	stat->cpu = cpu;
208	cpufreq_stats_table[cpu] = stat;
209
210	for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
211		unsigned int freq = table[i].frequency;
212		if (freq == CPUFREQ_ENTRY_INVALID)
213			continue;
214		count++;
215	}
216
217	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
218
219#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
220	alloc_size += count * count * sizeof(int);
221#endif
222	stat->max_state = count;
223	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
224	if (!stat->time_in_state) {
225		ret = -ENOMEM;
226		goto error_out;
227	}
228	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
229
230#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
231	stat->trans_table = stat->freq_table + count;
232#endif
233	j = 0;
234	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
235		unsigned int freq = table[i].frequency;
236		if (freq == CPUFREQ_ENTRY_INVALID)
237			continue;
238		if (freq_table_get_index(stat, freq) == -1)
239			stat->freq_table[j++] = freq;
240	}
241	stat->state_num = j;
242	spin_lock(&cpufreq_stats_lock);
243	stat->last_time = get_jiffies_64();
244	stat->last_index = freq_table_get_index(stat, policy->cur);
245	spin_unlock(&cpufreq_stats_lock);
246	cpufreq_cpu_put(data);
247	return 0;
248error_out:
249	cpufreq_cpu_put(data);
250error_get_fail:
251	kfree(stat);
252	cpufreq_stats_table[cpu] = NULL;
253	return ret;
254}
255
256static int
257cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
258		void *data)
259{
260	int ret;
261	struct cpufreq_policy *policy = data;
262	struct cpufreq_frequency_table *table;
263	unsigned int cpu = policy->cpu;
264	if (val != CPUFREQ_NOTIFY)
265		return 0;
266	table = cpufreq_frequency_get_table(cpu);
267	if (!table)
268		return 0;
269	if ((ret = cpufreq_stats_create_table(policy, table)))
270		return ret;
271	return 0;
272}
273
274static int
275cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
276		void *data)
277{
278	struct cpufreq_freqs *freq = data;
279	struct cpufreq_stats *stat;
280	int old_index, new_index;
281
282	if (val != CPUFREQ_POSTCHANGE)
283		return 0;
284
285	stat = cpufreq_stats_table[freq->cpu];
286	if (!stat)
287		return 0;
288
289	old_index = freq_table_get_index(stat, freq->old);
290	new_index = freq_table_get_index(stat, freq->new);
291
292	cpufreq_stats_update(freq->cpu);
293	if (old_index == new_index)
294		return 0;
295
296	if (old_index == -1 || new_index == -1)
297		return 0;
298
299	spin_lock(&cpufreq_stats_lock);
300	stat->last_index = new_index;
301#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
302	stat->trans_table[old_index * stat->max_state + new_index]++;
303#endif
304	stat->total_trans++;
305	spin_unlock(&cpufreq_stats_lock);
306	return 0;
307}
308
309static int cpufreq_stat_cpu_callback(struct notifier_block *nfb,
310					unsigned long action, void *hcpu)
311{
312	unsigned int cpu = (unsigned long)hcpu;
313
314	switch (action) {
315	case CPU_ONLINE:
316	case CPU_ONLINE_FROZEN:
317		cpufreq_update_policy(cpu);
318		break;
319	case CPU_DEAD:
320	case CPU_DEAD_FROZEN:
321		cpufreq_stats_free_table(cpu);
322		break;
323	}
324	return NOTIFY_OK;
325}
326
327static struct notifier_block cpufreq_stat_cpu_notifier =
328{
329	.notifier_call = cpufreq_stat_cpu_callback,
330};
331
332static struct notifier_block notifier_policy_block = {
333	.notifier_call = cpufreq_stat_notifier_policy
334};
335
336static struct notifier_block notifier_trans_block = {
337	.notifier_call = cpufreq_stat_notifier_trans
338};
339
340static int
341__init cpufreq_stats_init(void)
342{
343	int ret;
344	unsigned int cpu;
345
346	spin_lock_init(&cpufreq_stats_lock);
347	if ((ret = cpufreq_register_notifier(&notifier_policy_block,
348				CPUFREQ_POLICY_NOTIFIER)))
349		return ret;
350
351	if ((ret = cpufreq_register_notifier(&notifier_trans_block,
352				CPUFREQ_TRANSITION_NOTIFIER))) {
353		cpufreq_unregister_notifier(&notifier_policy_block,
354				CPUFREQ_POLICY_NOTIFIER);
355		return ret;
356	}
357
358	register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
359	for_each_online_cpu(cpu) {
360		cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier,
361				CPU_ONLINE, (void *)(long)cpu);
362	}
363	return 0;
364}
365static void
366__exit cpufreq_stats_exit(void)
367{
368	unsigned int cpu;
369
370	cpufreq_unregister_notifier(&notifier_policy_block,
371			CPUFREQ_POLICY_NOTIFIER);
372	cpufreq_unregister_notifier(&notifier_trans_block,
373			CPUFREQ_TRANSITION_NOTIFIER);
374	unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
375	for_each_online_cpu(cpu) {
376		cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier,
377						CPU_DEAD, (void *)(long)cpu);
378	}
379}
380
381MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
382MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats"
383				"through sysfs filesystem");
384MODULE_LICENSE ("GPL");
385
386module_init(cpufreq_stats_init);
387module_exit(cpufreq_stats_exit);
388