1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  drivers/cpufreq/cpufreq_stats.c
4  *
5  *  Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
6  *  (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
7  */
8 
9 #include <linux/cpu.h>
10 #include <linux/cpufreq.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 
14 
15 struct cpufreq_stats {
16 	unsigned int total_trans;
17 	unsigned long long last_time;
18 	unsigned int max_state;
19 	unsigned int state_num;
20 	unsigned int last_index;
21 	u64 *time_in_state;
22 	spinlock_t lock;
23 	unsigned int *freq_table;
24 	unsigned int *trans_table;
25 };
26 
27 static void cpufreq_stats_update(struct cpufreq_stats *stats)
28 {
29 	unsigned long long cur_time = get_jiffies_64();
30 
31 	stats->time_in_state[stats->last_index] += cur_time - stats->last_time;
32 	stats->last_time = cur_time;
33 }
34 
35 static void cpufreq_stats_clear_table(struct cpufreq_stats *stats)
36 {
37 	unsigned int count = stats->max_state;
38 
39 	spin_lock(&stats->lock);
40 	memset(stats->time_in_state, 0, count * sizeof(u64));
41 	memset(stats->trans_table, 0, count * count * sizeof(int));
42 	stats->last_time = get_jiffies_64();
43 	stats->total_trans = 0;
44 	spin_unlock(&stats->lock);
45 }
46 
47 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
48 {
49 	return sprintf(buf, "%d\n", policy->stats->total_trans);
50 }
51 cpufreq_freq_attr_ro(total_trans);
52 
53 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
54 {
55 	struct cpufreq_stats *stats = policy->stats;
56 	ssize_t len = 0;
57 	int i;
58 
59 	if (policy->fast_switch_enabled)
60 		return 0;
61 
62 	spin_lock(&stats->lock);
63 	cpufreq_stats_update(stats);
64 	spin_unlock(&stats->lock);
65 
66 	for (i = 0; i < stats->state_num; i++) {
67 		len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],
68 			(unsigned long long)
69 			jiffies_64_to_clock_t(stats->time_in_state[i]));
70 	}
71 	return len;
72 }
73 cpufreq_freq_attr_ro(time_in_state);
74 
75 static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
76 			   size_t count)
77 {
78 	/* We don't care what is written to the attribute. */
79 	cpufreq_stats_clear_table(policy->stats);
80 	return count;
81 }
82 cpufreq_freq_attr_wo(reset);
83 
84 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
85 {
86 	struct cpufreq_stats *stats = policy->stats;
87 	ssize_t len = 0;
88 	int i, j;
89 
90 	if (policy->fast_switch_enabled)
91 		return 0;
92 
93 	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
94 	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
95 	for (i = 0; i < stats->state_num; i++) {
96 		if (len >= PAGE_SIZE)
97 			break;
98 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
99 				stats->freq_table[i]);
100 	}
101 	if (len >= PAGE_SIZE)
102 		return PAGE_SIZE;
103 
104 	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
105 
106 	for (i = 0; i < stats->state_num; i++) {
107 		if (len >= PAGE_SIZE)
108 			break;
109 
110 		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
111 				stats->freq_table[i]);
112 
113 		for (j = 0; j < stats->state_num; j++) {
114 			if (len >= PAGE_SIZE)
115 				break;
116 			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
117 					stats->trans_table[i*stats->max_state+j]);
118 		}
119 		if (len >= PAGE_SIZE)
120 			break;
121 		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
122 	}
123 
124 	if (len >= PAGE_SIZE) {
125 		pr_warn_once("cpufreq transition table exceeds PAGE_SIZE. Disabling\n");
126 		return -EFBIG;
127 	}
128 	return len;
129 }
130 cpufreq_freq_attr_ro(trans_table);
131 
132 static struct attribute *default_attrs[] = {
133 	&total_trans.attr,
134 	&time_in_state.attr,
135 	&reset.attr,
136 	&trans_table.attr,
137 	NULL
138 };
139 static const struct attribute_group stats_attr_group = {
140 	.attrs = default_attrs,
141 	.name = "stats"
142 };
143 
144 static int freq_table_get_index(struct cpufreq_stats *stats, unsigned int freq)
145 {
146 	int index;
147 	for (index = 0; index < stats->max_state; index++)
148 		if (stats->freq_table[index] == freq)
149 			return index;
150 	return -1;
151 }
152 
153 void cpufreq_stats_free_table(struct cpufreq_policy *policy)
154 {
155 	struct cpufreq_stats *stats = policy->stats;
156 
157 	/* Already freed */
158 	if (!stats)
159 		return;
160 
161 	pr_debug("%s: Free stats table\n", __func__);
162 
163 	sysfs_remove_group(&policy->kobj, &stats_attr_group);
164 	kfree(stats->time_in_state);
165 	kfree(stats);
166 	policy->stats = NULL;
167 }
168 
169 void cpufreq_stats_create_table(struct cpufreq_policy *policy)
170 {
171 	unsigned int i = 0, count = 0, ret = -ENOMEM;
172 	struct cpufreq_stats *stats;
173 	unsigned int alloc_size;
174 	struct cpufreq_frequency_table *pos;
175 
176 	count = cpufreq_table_count_valid_entries(policy);
177 	if (!count)
178 		return;
179 
180 	/* stats already initialized */
181 	if (policy->stats)
182 		return;
183 
184 	stats = kzalloc(sizeof(*stats), GFP_KERNEL);
185 	if (!stats)
186 		return;
187 
188 	alloc_size = count * sizeof(int) + count * sizeof(u64);
189 
190 	alloc_size += count * count * sizeof(int);
191 
192 	/* Allocate memory for time_in_state/freq_table/trans_table in one go */
193 	stats->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
194 	if (!stats->time_in_state)
195 		goto free_stat;
196 
197 	stats->freq_table = (unsigned int *)(stats->time_in_state + count);
198 
199 	stats->trans_table = stats->freq_table + count;
200 
201 	stats->max_state = count;
202 
203 	/* Find valid-unique entries */
204 	cpufreq_for_each_valid_entry(pos, policy->freq_table)
205 		if (freq_table_get_index(stats, pos->frequency) == -1)
206 			stats->freq_table[i++] = pos->frequency;
207 
208 	stats->state_num = i;
209 	stats->last_time = get_jiffies_64();
210 	stats->last_index = freq_table_get_index(stats, policy->cur);
211 	spin_lock_init(&stats->lock);
212 
213 	policy->stats = stats;
214 	ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
215 	if (!ret)
216 		return;
217 
218 	/* We failed, release resources */
219 	policy->stats = NULL;
220 	kfree(stats->time_in_state);
221 free_stat:
222 	kfree(stats);
223 }
224 
225 void cpufreq_stats_record_transition(struct cpufreq_policy *policy,
226 				     unsigned int new_freq)
227 {
228 	struct cpufreq_stats *stats = policy->stats;
229 	int old_index, new_index;
230 
231 	if (!stats) {
232 		pr_debug("%s: No stats found\n", __func__);
233 		return;
234 	}
235 
236 	old_index = stats->last_index;
237 	new_index = freq_table_get_index(stats, new_freq);
238 
239 	/* We can't do stats->time_in_state[-1]= .. */
240 	if (old_index == -1 || new_index == -1 || old_index == new_index)
241 		return;
242 
243 	spin_lock(&stats->lock);
244 	cpufreq_stats_update(stats);
245 
246 	stats->last_index = new_index;
247 	stats->trans_table[old_index * stats->max_state + new_index]++;
248 	stats->total_trans++;
249 	spin_unlock(&stats->lock);
250 }
251