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 
24 static spinlock_t cpufreq_stats_lock;
25 
26 #define CPUFREQ_STATDEVICE_ATTR(_name, _mode, _show) \
27 static struct freq_attr _attr_##_name = {\
28 	.attr = {.name = __stringify(_name), .mode = _mode, }, \
29 	.show = _show,\
30 };
31 
32 struct cpufreq_stats {
33 	unsigned int cpu;
34 	unsigned int total_trans;
35 	unsigned long long  last_time;
36 	unsigned int max_state;
37 	unsigned int state_num;
38 	unsigned int last_index;
39 	cputime64_t *time_in_state;
40 	unsigned int *freq_table;
41 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
42 	unsigned int *trans_table;
43 #endif
44 };
45 
46 static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
47 
48 struct cpufreq_stats_attribute {
49 	struct attribute attr;
50 	ssize_t(*show) (struct cpufreq_stats *, char *);
51 };
52 
53 static int cpufreq_stats_update(unsigned int cpu)
54 {
55 	struct cpufreq_stats *stat;
56 	unsigned long long cur_time;
57 
58 	cur_time = get_jiffies_64();
59 	spin_lock(&cpufreq_stats_lock);
60 	stat = per_cpu(cpufreq_stats_table, cpu);
61 	if (stat->time_in_state)
62 		stat->time_in_state[stat->last_index] =
63 			cputime64_add(stat->time_in_state[stat->last_index],
64 				      cputime_sub(cur_time, stat->last_time));
65 	stat->last_time = cur_time;
66 	spin_unlock(&cpufreq_stats_lock);
67 	return 0;
68 }
69 
70 static 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 
79 static 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
96 static 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 }
139 CPUFREQ_STATDEVICE_ATTR(trans_table, 0444, show_trans_table);
140 #endif
141 
142 CPUFREQ_STATDEVICE_ATTR(total_trans, 0444, show_total_trans);
143 CPUFREQ_STATDEVICE_ATTR(time_in_state, 0444, show_time_in_state);
144 
145 static 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 };
153 static struct attribute_group stats_attr_group = {
154 	.attrs = default_attrs,
155 	.name = "stats"
156 };
157 
158 static 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 static void cpufreq_stats_free_table(unsigned int cpu)
168 {
169 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
170 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
171 	if (policy && policy->cpu == cpu)
172 		sysfs_remove_group(&policy->kobj, &stats_attr_group);
173 	if (stat) {
174 		kfree(stat->time_in_state);
175 		kfree(stat);
176 	}
177 	per_cpu(cpufreq_stats_table, cpu) = NULL;
178 	if (policy)
179 		cpufreq_cpu_put(policy);
180 }
181 
182 static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
183 		struct cpufreq_frequency_table *table)
184 {
185 	unsigned int i, j, count = 0, ret = 0;
186 	struct cpufreq_stats *stat;
187 	struct cpufreq_policy *data;
188 	unsigned int alloc_size;
189 	unsigned int cpu = policy->cpu;
190 	if (per_cpu(cpufreq_stats_table, cpu))
191 		return -EBUSY;
192 	stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL);
193 	if ((stat) == NULL)
194 		return -ENOMEM;
195 
196 	data = cpufreq_cpu_get(cpu);
197 	if (data == NULL) {
198 		ret = -EINVAL;
199 		goto error_get_fail;
200 	}
201 
202 	ret = sysfs_create_group(&data->kobj, &stats_attr_group);
203 	if (ret)
204 		goto error_out;
205 
206 	stat->cpu = cpu;
207 	per_cpu(cpufreq_stats_table, cpu) = stat;
208 
209 	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
210 		unsigned int freq = table[i].frequency;
211 		if (freq == CPUFREQ_ENTRY_INVALID)
212 			continue;
213 		count++;
214 	}
215 
216 	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
217 
218 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
219 	alloc_size += count * count * sizeof(int);
220 #endif
221 	stat->max_state = count;
222 	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
223 	if (!stat->time_in_state) {
224 		ret = -ENOMEM;
225 		goto error_out;
226 	}
227 	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
228 
229 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
230 	stat->trans_table = stat->freq_table + count;
231 #endif
232 	j = 0;
233 	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
234 		unsigned int freq = table[i].frequency;
235 		if (freq == CPUFREQ_ENTRY_INVALID)
236 			continue;
237 		if (freq_table_get_index(stat, freq) == -1)
238 			stat->freq_table[j++] = freq;
239 	}
240 	stat->state_num = j;
241 	spin_lock(&cpufreq_stats_lock);
242 	stat->last_time = get_jiffies_64();
243 	stat->last_index = freq_table_get_index(stat, policy->cur);
244 	spin_unlock(&cpufreq_stats_lock);
245 	cpufreq_cpu_put(data);
246 	return 0;
247 error_out:
248 	cpufreq_cpu_put(data);
249 error_get_fail:
250 	kfree(stat);
251 	per_cpu(cpufreq_stats_table, cpu) = NULL;
252 	return ret;
253 }
254 
255 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
256 		unsigned long val, void *data)
257 {
258 	int ret;
259 	struct cpufreq_policy *policy = data;
260 	struct cpufreq_frequency_table *table;
261 	unsigned int cpu = policy->cpu;
262 	if (val != CPUFREQ_NOTIFY)
263 		return 0;
264 	table = cpufreq_frequency_get_table(cpu);
265 	if (!table)
266 		return 0;
267 	ret = cpufreq_stats_create_table(policy, table);
268 	if (ret)
269 		return ret;
270 	return 0;
271 }
272 
273 static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
274 		unsigned long val, void *data)
275 {
276 	struct cpufreq_freqs *freq = data;
277 	struct cpufreq_stats *stat;
278 	int old_index, new_index;
279 
280 	if (val != CPUFREQ_POSTCHANGE)
281 		return 0;
282 
283 	stat = per_cpu(cpufreq_stats_table, freq->cpu);
284 	if (!stat)
285 		return 0;
286 
287 	old_index = stat->last_index;
288 	new_index = freq_table_get_index(stat, freq->new);
289 
290 	cpufreq_stats_update(freq->cpu);
291 	if (old_index == new_index)
292 		return 0;
293 
294 	if (old_index == -1 || new_index == -1)
295 		return 0;
296 
297 	spin_lock(&cpufreq_stats_lock);
298 	stat->last_index = new_index;
299 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
300 	stat->trans_table[old_index * stat->max_state + new_index]++;
301 #endif
302 	stat->total_trans++;
303 	spin_unlock(&cpufreq_stats_lock);
304 	return 0;
305 }
306 
307 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
308 					       unsigned long action,
309 					       void *hcpu)
310 {
311 	unsigned int cpu = (unsigned long)hcpu;
312 
313 	switch (action) {
314 	case CPU_ONLINE:
315 	case CPU_ONLINE_FROZEN:
316 		cpufreq_update_policy(cpu);
317 		break;
318 	case CPU_DEAD:
319 	case CPU_DEAD_FROZEN:
320 		cpufreq_stats_free_table(cpu);
321 		break;
322 	}
323 	return NOTIFY_OK;
324 }
325 
326 static struct notifier_block cpufreq_stat_cpu_notifier __refdata =
327 {
328 	.notifier_call = cpufreq_stat_cpu_callback,
329 };
330 
331 static struct notifier_block notifier_policy_block = {
332 	.notifier_call = cpufreq_stat_notifier_policy
333 };
334 
335 static struct notifier_block notifier_trans_block = {
336 	.notifier_call = cpufreq_stat_notifier_trans
337 };
338 
339 static int __init cpufreq_stats_init(void)
340 {
341 	int ret;
342 	unsigned int cpu;
343 
344 	spin_lock_init(&cpufreq_stats_lock);
345 	ret = cpufreq_register_notifier(&notifier_policy_block,
346 				CPUFREQ_POLICY_NOTIFIER);
347 	if (ret)
348 		return ret;
349 
350 	ret = cpufreq_register_notifier(&notifier_trans_block,
351 				CPUFREQ_TRANSITION_NOTIFIER);
352 	if (ret) {
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_update_policy(cpu);
361 	}
362 	return 0;
363 }
364 static void __exit cpufreq_stats_exit(void)
365 {
366 	unsigned int cpu;
367 
368 	cpufreq_unregister_notifier(&notifier_policy_block,
369 			CPUFREQ_POLICY_NOTIFIER);
370 	cpufreq_unregister_notifier(&notifier_trans_block,
371 			CPUFREQ_TRANSITION_NOTIFIER);
372 	unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
373 	for_each_online_cpu(cpu) {
374 		cpufreq_stats_free_table(cpu);
375 	}
376 }
377 
378 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
379 MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
380 				"through sysfs filesystem");
381 MODULE_LICENSE("GPL");
382 
383 module_init(cpufreq_stats_init);
384 module_exit(cpufreq_stats_exit);
385