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
54 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 			cputime64_add(stat->time_in_state[stat->last_index],
65 				      cputime_sub(cur_time, stat->last_time));
66 	stat->last_time = cur_time;
67 	spin_unlock(&cpufreq_stats_lock);
68 	return 0;
69 }
70 
71 static ssize_t
72 show_total_trans(struct cpufreq_policy *policy, char *buf)
73 {
74 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
75 	if (!stat)
76 		return 0;
77 	return sprintf(buf, "%d\n",
78 			per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
79 }
80 
81 static ssize_t
82 show_time_in_state(struct cpufreq_policy *policy, char *buf)
83 {
84 	ssize_t len = 0;
85 	int i;
86 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
87 	if (!stat)
88 		return 0;
89 	cpufreq_stats_update(stat->cpu);
90 	for (i = 0; i < stat->state_num; i++) {
91 		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
92 			(unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
93 	}
94 	return len;
95 }
96 
97 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
98 static ssize_t
99 show_trans_table(struct cpufreq_policy *policy, char *buf)
100 {
101 	ssize_t len = 0;
102 	int i, j;
103 
104 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
105 	if (!stat)
106 		return 0;
107 	cpufreq_stats_update(stat->cpu);
108 	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
109 	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
110 	for (i = 0; i < stat->state_num; i++) {
111 		if (len >= PAGE_SIZE)
112 			break;
113 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
114 				stat->freq_table[i]);
115 	}
116 	if (len >= PAGE_SIZE)
117 		return PAGE_SIZE;
118 
119 	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
120 
121 	for (i = 0; i < stat->state_num; i++) {
122 		if (len >= PAGE_SIZE)
123 			break;
124 
125 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
126 				stat->freq_table[i]);
127 
128 		for (j = 0; j < stat->state_num; j++)   {
129 			if (len >= PAGE_SIZE)
130 				break;
131 			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
132 					stat->trans_table[i*stat->max_state+j]);
133 		}
134 		if (len >= PAGE_SIZE)
135 			break;
136 		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
137 	}
138 	if (len >= PAGE_SIZE)
139 		return PAGE_SIZE;
140 	return len;
141 }
142 CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
143 #endif
144 
145 CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
146 CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);
147 
148 static struct attribute *default_attrs[] = {
149 	&_attr_total_trans.attr,
150 	&_attr_time_in_state.attr,
151 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
152 	&_attr_trans_table.attr,
153 #endif
154 	NULL
155 };
156 static struct attribute_group stats_attr_group = {
157 	.attrs = default_attrs,
158 	.name = "stats"
159 };
160 
161 static int
162 freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
163 {
164 	int index;
165 	for (index = 0; index < stat->max_state; index++)
166 		if (stat->freq_table[index] == freq)
167 			return index;
168 	return -1;
169 }
170 
171 static void cpufreq_stats_free_table(unsigned int cpu)
172 {
173 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
174 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
175 	if (policy && policy->cpu == cpu)
176 		sysfs_remove_group(&policy->kobj, &stats_attr_group);
177 	if (stat) {
178 		kfree(stat->time_in_state);
179 		kfree(stat);
180 	}
181 	per_cpu(cpufreq_stats_table, cpu) = NULL;
182 	if (policy)
183 		cpufreq_cpu_put(policy);
184 }
185 
186 static int
187 cpufreq_stats_create_table (struct cpufreq_policy *policy,
188 		struct cpufreq_frequency_table *table)
189 {
190 	unsigned int i, j, count = 0, ret = 0;
191 	struct cpufreq_stats *stat;
192 	struct cpufreq_policy *data;
193 	unsigned int alloc_size;
194 	unsigned int cpu = policy->cpu;
195 	if (per_cpu(cpufreq_stats_table, cpu))
196 		return -EBUSY;
197 	if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
198 		return -ENOMEM;
199 
200 	data = cpufreq_cpu_get(cpu);
201 	if (data == NULL) {
202 		ret = -EINVAL;
203 		goto error_get_fail;
204 	}
205 
206 	if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
207 		goto error_out;
208 
209 	stat->cpu = cpu;
210 	per_cpu(cpufreq_stats_table, cpu) = stat;
211 
212 	for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
213 		unsigned int freq = table[i].frequency;
214 		if (freq == CPUFREQ_ENTRY_INVALID)
215 			continue;
216 		count++;
217 	}
218 
219 	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
220 
221 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
222 	alloc_size += count * count * sizeof(int);
223 #endif
224 	stat->max_state = count;
225 	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
226 	if (!stat->time_in_state) {
227 		ret = -ENOMEM;
228 		goto error_out;
229 	}
230 	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
231 
232 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
233 	stat->trans_table = stat->freq_table + count;
234 #endif
235 	j = 0;
236 	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
237 		unsigned int freq = table[i].frequency;
238 		if (freq == CPUFREQ_ENTRY_INVALID)
239 			continue;
240 		if (freq_table_get_index(stat, freq) == -1)
241 			stat->freq_table[j++] = freq;
242 	}
243 	stat->state_num = j;
244 	spin_lock(&cpufreq_stats_lock);
245 	stat->last_time = get_jiffies_64();
246 	stat->last_index = freq_table_get_index(stat, policy->cur);
247 	spin_unlock(&cpufreq_stats_lock);
248 	cpufreq_cpu_put(data);
249 	return 0;
250 error_out:
251 	cpufreq_cpu_put(data);
252 error_get_fail:
253 	kfree(stat);
254 	per_cpu(cpufreq_stats_table, cpu) = NULL;
255 	return ret;
256 }
257 
258 static int
259 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
260 		void *data)
261 {
262 	int ret;
263 	struct cpufreq_policy *policy = data;
264 	struct cpufreq_frequency_table *table;
265 	unsigned int cpu = policy->cpu;
266 	if (val != CPUFREQ_NOTIFY)
267 		return 0;
268 	table = cpufreq_frequency_get_table(cpu);
269 	if (!table)
270 		return 0;
271 	if ((ret = cpufreq_stats_create_table(policy, table)))
272 		return ret;
273 	return 0;
274 }
275 
276 static int
277 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
278 		void *data)
279 {
280 	struct cpufreq_freqs *freq = data;
281 	struct cpufreq_stats *stat;
282 	int old_index, new_index;
283 
284 	if (val != CPUFREQ_POSTCHANGE)
285 		return 0;
286 
287 	stat = per_cpu(cpufreq_stats_table, freq->cpu);
288 	if (!stat)
289 		return 0;
290 
291 	old_index = stat->last_index;
292 	new_index = freq_table_get_index(stat, freq->new);
293 
294 	cpufreq_stats_update(freq->cpu);
295 	if (old_index == new_index)
296 		return 0;
297 
298 	if (old_index == -1 || new_index == -1)
299 		return 0;
300 
301 	spin_lock(&cpufreq_stats_lock);
302 	stat->last_index = new_index;
303 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
304 	stat->trans_table[old_index * stat->max_state + new_index]++;
305 #endif
306 	stat->total_trans++;
307 	spin_unlock(&cpufreq_stats_lock);
308 	return 0;
309 }
310 
311 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
312 					       unsigned long action,
313 					       void *hcpu)
314 {
315 	unsigned int cpu = (unsigned long)hcpu;
316 
317 	switch (action) {
318 	case CPU_ONLINE:
319 	case CPU_ONLINE_FROZEN:
320 		cpufreq_update_policy(cpu);
321 		break;
322 	case CPU_DEAD:
323 	case CPU_DEAD_FROZEN:
324 		cpufreq_stats_free_table(cpu);
325 		break;
326 	}
327 	return NOTIFY_OK;
328 }
329 
330 static struct notifier_block cpufreq_stat_cpu_notifier __refdata =
331 {
332 	.notifier_call = cpufreq_stat_cpu_callback,
333 };
334 
335 static struct notifier_block notifier_policy_block = {
336 	.notifier_call = cpufreq_stat_notifier_policy
337 };
338 
339 static struct notifier_block notifier_trans_block = {
340 	.notifier_call = cpufreq_stat_notifier_trans
341 };
342 
343 static int
344 __init cpufreq_stats_init(void)
345 {
346 	int ret;
347 	unsigned int cpu;
348 
349 	spin_lock_init(&cpufreq_stats_lock);
350 	if ((ret = cpufreq_register_notifier(&notifier_policy_block,
351 				CPUFREQ_POLICY_NOTIFIER)))
352 		return ret;
353 
354 	if ((ret = cpufreq_register_notifier(&notifier_trans_block,
355 				CPUFREQ_TRANSITION_NOTIFIER))) {
356 		cpufreq_unregister_notifier(&notifier_policy_block,
357 				CPUFREQ_POLICY_NOTIFIER);
358 		return ret;
359 	}
360 
361 	register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
362 	for_each_online_cpu(cpu) {
363 		cpufreq_update_policy(cpu);
364 	}
365 	return 0;
366 }
367 static void
368 __exit cpufreq_stats_exit(void)
369 {
370 	unsigned int cpu;
371 
372 	cpufreq_unregister_notifier(&notifier_policy_block,
373 			CPUFREQ_POLICY_NOTIFIER);
374 	cpufreq_unregister_notifier(&notifier_trans_block,
375 			CPUFREQ_TRANSITION_NOTIFIER);
376 	unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
377 	for_each_online_cpu(cpu) {
378 		cpufreq_stats_free_table(cpu);
379 	}
380 }
381 
382 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
383 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats "
384 				"through sysfs filesystem");
385 MODULE_LICENSE ("GPL");
386 
387 module_init(cpufreq_stats_init);
388 module_exit(cpufreq_stats_exit);
389