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 struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];
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 = 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 = cpufreq_stats_table[policy->cpu];
75 	if (!stat)
76 		return 0;
77 	return sprintf(buf, "%d\n",
78 			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 = 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 = 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 len;
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 		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
135 	}
136 	return len;
137 }
138 CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
139 #endif
140 
141 CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
142 CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);
143 
144 static struct attribute *default_attrs[] = {
145 	&_attr_total_trans.attr,
146 	&_attr_time_in_state.attr,
147 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
148 	&_attr_trans_table.attr,
149 #endif
150 	NULL
151 };
152 static struct attribute_group stats_attr_group = {
153 	.attrs = default_attrs,
154 	.name = "stats"
155 };
156 
157 static int
158 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
168 cpufreq_stats_free_table (unsigned int cpu)
169 {
170 	struct cpufreq_stats *stat = cpufreq_stats_table[cpu];
171 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
172 	if (policy && policy->cpu == cpu)
173 		sysfs_remove_group(&policy->kobj, &stats_attr_group);
174 	if (stat) {
175 		kfree(stat->time_in_state);
176 		kfree(stat);
177 	}
178 	cpufreq_stats_table[cpu] = NULL;
179 	if (policy)
180 		cpufreq_cpu_put(policy);
181 }
182 
183 static int
184 cpufreq_stats_create_table (struct cpufreq_policy *policy,
185 		struct cpufreq_frequency_table *table)
186 {
187 	unsigned int i, j, count = 0, ret = 0;
188 	struct cpufreq_stats *stat;
189 	struct cpufreq_policy *data;
190 	unsigned int alloc_size;
191 	unsigned int cpu = policy->cpu;
192 	if (cpufreq_stats_table[cpu])
193 		return -EBUSY;
194 	if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
195 		return -ENOMEM;
196 
197 	data = cpufreq_cpu_get(cpu);
198 	if (data == NULL) {
199 		ret = -EINVAL;
200 		goto error_get_fail;
201 	}
202 
203 	if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
204 		goto error_out;
205 
206 	stat->cpu = cpu;
207 	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 	cpufreq_stats_table[cpu] = NULL;
252 	return ret;
253 }
254 
255 static int
256 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
257 		void *data)
258 {
259 	int ret;
260 	struct cpufreq_policy *policy = data;
261 	struct cpufreq_frequency_table *table;
262 	unsigned int cpu = policy->cpu;
263 	if (val != CPUFREQ_NOTIFY)
264 		return 0;
265 	table = cpufreq_frequency_get_table(cpu);
266 	if (!table)
267 		return 0;
268 	if ((ret = cpufreq_stats_create_table(policy, table)))
269 		return ret;
270 	return 0;
271 }
272 
273 static int
274 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
275 		void *data)
276 {
277 	struct cpufreq_freqs *freq = data;
278 	struct cpufreq_stats *stat;
279 	int old_index, new_index;
280 
281 	if (val != CPUFREQ_POSTCHANGE)
282 		return 0;
283 
284 	stat = cpufreq_stats_table[freq->cpu];
285 	if (!stat)
286 		return 0;
287 
288 	old_index = freq_table_get_index(stat, freq->old);
289 	new_index = freq_table_get_index(stat, freq->new);
290 
291 	cpufreq_stats_update(freq->cpu);
292 	if (old_index == new_index)
293 		return 0;
294 
295 	if (old_index == -1 || new_index == -1)
296 		return 0;
297 
298 	spin_lock(&cpufreq_stats_lock);
299 	stat->last_index = new_index;
300 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
301 	stat->trans_table[old_index * stat->max_state + new_index]++;
302 #endif
303 	stat->total_trans++;
304 	spin_unlock(&cpufreq_stats_lock);
305 	return 0;
306 }
307 
308 static int cpufreq_stat_cpu_callback(struct notifier_block *nfb,
309 					unsigned long action, 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 =
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
340 __init cpufreq_stats_init(void)
341 {
342 	int ret;
343 	unsigned int cpu;
344 
345 	spin_lock_init(&cpufreq_stats_lock);
346 	if ((ret = cpufreq_register_notifier(&notifier_policy_block,
347 				CPUFREQ_POLICY_NOTIFIER)))
348 		return ret;
349 
350 	if ((ret = cpufreq_register_notifier(&notifier_trans_block,
351 				CPUFREQ_TRANSITION_NOTIFIER))) {
352 		cpufreq_unregister_notifier(&notifier_policy_block,
353 				CPUFREQ_POLICY_NOTIFIER);
354 		return ret;
355 	}
356 
357 	register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
358 	for_each_online_cpu(cpu) {
359 		cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier,
360 				CPU_ONLINE, (void *)(long)cpu);
361 	}
362 	return 0;
363 }
364 static void
365 __exit cpufreq_stats_exit(void)
366 {
367 	unsigned int cpu;
368 
369 	cpufreq_unregister_notifier(&notifier_policy_block,
370 			CPUFREQ_POLICY_NOTIFIER);
371 	cpufreq_unregister_notifier(&notifier_trans_block,
372 			CPUFREQ_TRANSITION_NOTIFIER);
373 	unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
374 	for_each_online_cpu(cpu) {
375 		cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier,
376 						CPU_DEAD, (void *)(long)cpu);
377 	}
378 }
379 
380 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
381 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats"
382 				"through sysfs filesystem");
383 MODULE_LICENSE ("GPL");
384 
385 module_init(cpufreq_stats_init);
386 module_exit(cpufreq_stats_exit);
387