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/config.h>
13 #include <linux/kernel.h>
14 #include <linux/sysdev.h>
15 #include <linux/cpu.h>
16 #include <linux/sysfs.h>
17 #include <linux/cpufreq.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 
25 static spinlock_t cpufreq_stats_lock;
26 
27 #define CPUFREQ_STATDEVICE_ATTR(_name,_mode,_show) \
28 static struct freq_attr _attr_##_name = {\
29 	.attr = {.name = __stringify(_name), .owner = THIS_MODULE, \
30 		.mode = _mode, }, \
31 	.show = _show,\
32 };
33 
34 struct cpufreq_stats {
35 	unsigned int cpu;
36 	unsigned int total_trans;
37 	unsigned long long  last_time;
38 	unsigned int max_state;
39 	unsigned int state_num;
40 	unsigned int last_index;
41 	cputime64_t *time_in_state;
42 	unsigned int *freq_table;
43 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
44 	unsigned int *trans_table;
45 #endif
46 };
47 
48 static struct cpufreq_stats *cpufreq_stats_table[NR_CPUS];
49 
50 struct cpufreq_stats_attribute {
51 	struct attribute attr;
52 	ssize_t(*show) (struct cpufreq_stats *, char *);
53 };
54 
55 static int
56 cpufreq_stats_update (unsigned int cpu)
57 {
58 	struct cpufreq_stats *stat;
59 	unsigned long long cur_time;
60 
61 	cur_time = get_jiffies_64();
62 	spin_lock(&cpufreq_stats_lock);
63 	stat = cpufreq_stats_table[cpu];
64 	if (stat->time_in_state)
65 		stat->time_in_state[stat->last_index] =
66 			cputime64_add(stat->time_in_state[stat->last_index],
67 				      cputime_sub(cur_time, stat->last_time));
68 	stat->last_time = cur_time;
69 	spin_unlock(&cpufreq_stats_lock);
70 	return 0;
71 }
72 
73 static ssize_t
74 show_total_trans(struct cpufreq_policy *policy, char *buf)
75 {
76 	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
77 	if(!stat)
78 		return 0;
79 	return sprintf(buf, "%d\n",
80 			cpufreq_stats_table[stat->cpu]->total_trans);
81 }
82 
83 static ssize_t
84 show_time_in_state(struct cpufreq_policy *policy, char *buf)
85 {
86 	ssize_t len = 0;
87 	int i;
88 	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
89 	if(!stat)
90 		return 0;
91 	cpufreq_stats_update(stat->cpu);
92 	for (i = 0; i < stat->state_num; i++) {
93 		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
94 			(unsigned long long)cputime64_to_clock_t(stat->time_in_state[i]));
95 	}
96 	return len;
97 }
98 
99 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
100 static ssize_t
101 show_trans_table(struct cpufreq_policy *policy, char *buf)
102 {
103 	ssize_t len = 0;
104 	int i, j;
105 
106 	struct cpufreq_stats *stat = cpufreq_stats_table[policy->cpu];
107 	if(!stat)
108 		return 0;
109 	cpufreq_stats_update(stat->cpu);
110 	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
111 	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
112 	for (i = 0; i < stat->state_num; i++) {
113 		if (len >= PAGE_SIZE)
114 			break;
115 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
116 				stat->freq_table[i]);
117 	}
118 	if (len >= PAGE_SIZE)
119 		return len;
120 
121 	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
122 
123 	for (i = 0; i < stat->state_num; i++) {
124 		if (len >= PAGE_SIZE)
125 			break;
126 
127 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
128 				stat->freq_table[i]);
129 
130 		for (j = 0; j < stat->state_num; j++)   {
131 			if (len >= PAGE_SIZE)
132 				break;
133 			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
134 					stat->trans_table[i*stat->max_state+j]);
135 		}
136 		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
137 	}
138 	return len;
139 }
140 CPUFREQ_STATDEVICE_ATTR(trans_table,0444,show_trans_table);
141 #endif
142 
143 CPUFREQ_STATDEVICE_ATTR(total_trans,0444,show_total_trans);
144 CPUFREQ_STATDEVICE_ATTR(time_in_state,0444,show_time_in_state);
145 
146 static struct attribute *default_attrs[] = {
147 	&_attr_total_trans.attr,
148 	&_attr_time_in_state.attr,
149 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
150 	&_attr_trans_table.attr,
151 #endif
152 	NULL
153 };
154 static struct attribute_group stats_attr_group = {
155 	.attrs = default_attrs,
156 	.name = "stats"
157 };
158 
159 static int
160 freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
161 {
162 	int index;
163 	for (index = 0; index < stat->max_state; index++)
164 		if (stat->freq_table[index] == freq)
165 			return index;
166 	return -1;
167 }
168 
169 static void
170 cpufreq_stats_free_table (unsigned int cpu)
171 {
172 	struct cpufreq_stats *stat = cpufreq_stats_table[cpu];
173 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
174 	if (policy && policy->cpu == cpu)
175 		sysfs_remove_group(&policy->kobj, &stats_attr_group);
176 	if (stat) {
177 		kfree(stat->time_in_state);
178 		kfree(stat);
179 	}
180 	cpufreq_stats_table[cpu] = NULL;
181 	if (policy)
182 		cpufreq_cpu_put(policy);
183 }
184 
185 static int
186 cpufreq_stats_create_table (struct cpufreq_policy *policy,
187 		struct cpufreq_frequency_table *table)
188 {
189 	unsigned int i, j, count = 0, ret = 0;
190 	struct cpufreq_stats *stat;
191 	struct cpufreq_policy *data;
192 	unsigned int alloc_size;
193 	unsigned int cpu = policy->cpu;
194 	if (cpufreq_stats_table[cpu])
195 		return -EBUSY;
196 	if ((stat = kzalloc(sizeof(struct cpufreq_stats), GFP_KERNEL)) == NULL)
197 		return -ENOMEM;
198 
199 	data = cpufreq_cpu_get(cpu);
200 	if (data == NULL) {
201 		ret = -EINVAL;
202 		goto error_get_fail;
203 	}
204 
205 	if ((ret = sysfs_create_group(&data->kobj, &stats_attr_group)))
206 		goto error_out;
207 
208 	stat->cpu = cpu;
209 	cpufreq_stats_table[cpu] = stat;
210 
211 	for (i=0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
212 		unsigned int freq = table[i].frequency;
213 		if (freq == CPUFREQ_ENTRY_INVALID)
214 			continue;
215 		count++;
216 	}
217 
218 	alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
219 
220 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
221 	alloc_size += count * count * sizeof(int);
222 #endif
223 	stat->max_state = count;
224 	stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
225 	if (!stat->time_in_state) {
226 		ret = -ENOMEM;
227 		goto error_out;
228 	}
229 	stat->freq_table = (unsigned int *)(stat->time_in_state + count);
230 
231 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
232 	stat->trans_table = stat->freq_table + count;
233 #endif
234 	j = 0;
235 	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
236 		unsigned int freq = table[i].frequency;
237 		if (freq == CPUFREQ_ENTRY_INVALID)
238 			continue;
239 		if (freq_table_get_index(stat, freq) == -1)
240 			stat->freq_table[j++] = freq;
241 	}
242 	stat->state_num = j;
243 	spin_lock(&cpufreq_stats_lock);
244 	stat->last_time = get_jiffies_64();
245 	stat->last_index = freq_table_get_index(stat, policy->cur);
246 	spin_unlock(&cpufreq_stats_lock);
247 	cpufreq_cpu_put(data);
248 	return 0;
249 error_out:
250 	cpufreq_cpu_put(data);
251 error_get_fail:
252 	kfree(stat);
253 	cpufreq_stats_table[cpu] = NULL;
254 	return ret;
255 }
256 
257 static int
258 cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
259 		void *data)
260 {
261 	int ret;
262 	struct cpufreq_policy *policy = data;
263 	struct cpufreq_frequency_table *table;
264 	unsigned int cpu = policy->cpu;
265 	if (val != CPUFREQ_NOTIFY)
266 		return 0;
267 	table = cpufreq_frequency_get_table(cpu);
268 	if (!table)
269 		return 0;
270 	if ((ret = cpufreq_stats_create_table(policy, table)))
271 		return ret;
272 	return 0;
273 }
274 
275 static int
276 cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val,
277 		void *data)
278 {
279 	struct cpufreq_freqs *freq = data;
280 	struct cpufreq_stats *stat;
281 	int old_index, new_index;
282 
283 	if (val != CPUFREQ_POSTCHANGE)
284 		return 0;
285 
286 	stat = cpufreq_stats_table[freq->cpu];
287 	if (!stat)
288 		return 0;
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 	spin_lock(&cpufreq_stats_lock);
297 	stat->last_index = new_index;
298 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
299 	stat->trans_table[old_index * stat->max_state + new_index]++;
300 #endif
301 	stat->total_trans++;
302 	spin_unlock(&cpufreq_stats_lock);
303 	return 0;
304 }
305 
306 static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb,
307 					unsigned long action, void *hcpu)
308 {
309 	unsigned int cpu = (unsigned long)hcpu;
310 
311 	switch (action) {
312 	case CPU_ONLINE:
313 		cpufreq_update_policy(cpu);
314 		break;
315 	case CPU_DEAD:
316 		cpufreq_stats_free_table(cpu);
317 		break;
318 	}
319 	return NOTIFY_OK;
320 }
321 
322 static struct notifier_block cpufreq_stat_cpu_notifier =
323 {
324 	.notifier_call = cpufreq_stat_cpu_callback,
325 };
326 
327 static struct notifier_block notifier_policy_block = {
328 	.notifier_call = cpufreq_stat_notifier_policy
329 };
330 
331 static struct notifier_block notifier_trans_block = {
332 	.notifier_call = cpufreq_stat_notifier_trans
333 };
334 
335 static int
336 __init cpufreq_stats_init(void)
337 {
338 	int ret;
339 	unsigned int cpu;
340 
341 	spin_lock_init(&cpufreq_stats_lock);
342 	if ((ret = cpufreq_register_notifier(&notifier_policy_block,
343 				CPUFREQ_POLICY_NOTIFIER)))
344 		return ret;
345 
346 	if ((ret = cpufreq_register_notifier(&notifier_trans_block,
347 				CPUFREQ_TRANSITION_NOTIFIER))) {
348 		cpufreq_unregister_notifier(&notifier_policy_block,
349 				CPUFREQ_POLICY_NOTIFIER);
350 		return ret;
351 	}
352 
353 	register_cpu_notifier(&cpufreq_stat_cpu_notifier);
354 	lock_cpu_hotplug();
355 	for_each_online_cpu(cpu) {
356 		cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_ONLINE,
357 			(void *)(long)cpu);
358 	}
359 	unlock_cpu_hotplug();
360 	return 0;
361 }
362 static void
363 __exit cpufreq_stats_exit(void)
364 {
365 	unsigned int cpu;
366 
367 	cpufreq_unregister_notifier(&notifier_policy_block,
368 			CPUFREQ_POLICY_NOTIFIER);
369 	cpufreq_unregister_notifier(&notifier_trans_block,
370 			CPUFREQ_TRANSITION_NOTIFIER);
371 	unregister_cpu_notifier(&cpufreq_stat_cpu_notifier);
372 	lock_cpu_hotplug();
373 	for_each_online_cpu(cpu) {
374 		cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_DEAD,
375 			(void *)(long)cpu);
376 	}
377 	unlock_cpu_hotplug();
378 }
379 
380 MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>");
381 MODULE_DESCRIPTION ("'cpufreq_stats' - A driver to export cpufreq stats through sysfs filesystem");
382 MODULE_LICENSE ("GPL");
383 
384 module_init(cpufreq_stats_init);
385 module_exit(cpufreq_stats_exit);
386