aboutsummaryrefslogtreecommitdiff
path: root/tools/power/cpupower/utils/helpers/sysfs.c
blob: 0c534e79652b68c00de8aa3d30053319ee931d24 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
/*
 *  (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
 *  (C) 2011       Thomas Renninger <trenn@novell.com> Novell Inc.
 *
 *  Licensed under the terms of the GNU GPL License version 2.
 */

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#include "helpers/sysfs.h"

unsigned int sysfs_read_file(const char *path, char *buf, size_t buflen)
{
	int fd;
	size_t numread;

	if ( ( fd = open(path, O_RDONLY) ) == -1 )
		return 0;

	numread = read(fd, buf, buflen - 1);
	if ( numread < 1 )
	{
		close(fd);
		return 0;
	}

	buf[numread] = '\0';
	close(fd);

	return numread;
}

static unsigned int sysfs_write_file(const char *path,
				     const char *value, size_t len)
{
	int fd;
	size_t numwrite;

	if ( ( fd = open(path, O_WRONLY) ) == -1 )
		return 0;

	numwrite = write(fd, value, len);
	if ( numwrite < 1 )
	{
		close(fd);
		return 0;
	}
	close(fd);
	return numwrite;
}

/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */

/*
 * helper function to read file from /sys into given buffer
 * fname is a relative path under "cpuX/cpuidle/stateX/" dir
 * cstates starting with 0, C0 is not counted as cstate.
 * This means if you want C1 info, pass 0 as idlestate param
 */
unsigned int sysfs_idlestate_read_file(unsigned int cpu, unsigned int idlestate,
			     const char *fname, char *buf, size_t buflen)
{
	char path[SYSFS_PATH_MAX];
	int fd;
	size_t numread;

	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s",
		 cpu, idlestate, fname);

	if ( ( fd = open(path, O_RDONLY) ) == -1 )
		return 0;

	numread = read(fd, buf, buflen - 1);
	if ( numread < 1 )
	{
		close(fd);
		return 0;
	}

	buf[numread] = '\0';
	close(fd);

	return numread;
}

/* read access to files which contain one numeric value */

enum idlestate_value {
	IDLESTATE_USAGE,
	IDLESTATE_POWER,
	IDLESTATE_LATENCY,
	IDLESTATE_TIME,
	MAX_IDLESTATE_VALUE_FILES
};

static const char *idlestate_value_files[MAX_IDLESTATE_VALUE_FILES] = {
	[IDLESTATE_USAGE] = "usage",
	[IDLESTATE_POWER] = "power",
	[IDLESTATE_LATENCY] = "latency",
	[IDLESTATE_TIME]  = "time",
};

static unsigned long long sysfs_idlestate_get_one_value(unsigned int cpu,
						     unsigned int idlestate,
						     enum idlestate_value which)
{
	unsigned long long value;
	unsigned int len;
	char linebuf[MAX_LINE_LEN];
	char *endp;

	if ( which >= MAX_IDLESTATE_VALUE_FILES )
		return 0;

	if ( ( len = sysfs_idlestate_read_file(cpu, idlestate,
					    idlestate_value_files[which],
					    linebuf, sizeof(linebuf))) == 0 )
	{
		return 0;
	}

	value = strtoull(linebuf, &endp, 0);

	if ( endp == linebuf || errno == ERANGE )
		return 0;

	return value;
}

/* read access to files which contain one string */

enum idlestate_string {
	IDLESTATE_DESC,
	IDLESTATE_NAME,
	MAX_IDLESTATE_STRING_FILES
};

static const char *idlestate_string_files[MAX_IDLESTATE_STRING_FILES] = {
	[IDLESTATE_DESC] = "desc",
	[IDLESTATE_NAME] = "name",
};


static char * sysfs_idlestate_get_one_string(unsigned int cpu,
					  unsigned int idlestate,
					  enum idlestate_string which)
{
	char linebuf[MAX_LINE_LEN];
	char *result;
	unsigned int len;

	if (which >= MAX_IDLESTATE_STRING_FILES)
		return NULL;

	if ( ( len = sysfs_idlestate_read_file(cpu, idlestate,
					    idlestate_string_files[which],
					    linebuf, sizeof(linebuf))) == 0 )
		return NULL;

	if ( ( result = strdup(linebuf) ) == NULL )
		return NULL;

	if (result[strlen(result) - 1] == '\n')
		result[strlen(result) - 1] = '\0';

	return result;
}

unsigned long sysfs_get_idlestate_latency(unsigned int cpu, unsigned int idlestate)
{
	return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_LATENCY);
}

unsigned long sysfs_get_idlestate_usage(unsigned int cpu, unsigned int idlestate)
{
	return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_USAGE);
}

unsigned long long sysfs_get_idlestate_time(unsigned int cpu, unsigned int idlestate)
{
	return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_TIME);
}

char * sysfs_get_idlestate_name(unsigned int cpu, unsigned int idlestate)
{
	return sysfs_idlestate_get_one_string(cpu, idlestate, IDLESTATE_NAME);
}

char * sysfs_get_idlestate_desc(unsigned int cpu, unsigned int idlestate)
{
	return sysfs_idlestate_get_one_string(cpu, idlestate, IDLESTATE_DESC);
}

/*
 * Returns number of supported C-states of CPU core cpu
 * Negativ in error case
 * Zero if cpuidle does not export any C-states
 */
int sysfs_get_idlestate_count(unsigned int cpu)
{
	char file[SYSFS_PATH_MAX];
	struct stat statbuf;
	int idlestates = 1;


	snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpuidle");
	if ( stat(file, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
		return -ENODEV;

	snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpu%u/cpuidle/state0", cpu);
	if ( stat(file, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
		return 0;

	while(stat(file, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
		snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU
			 "cpu%u/cpuidle/state%d", cpu, idlestates);
		idlestates++;
	}
	idlestates--;
	return idlestates;
}

/* CPUidle general /sys/devices/system/cpu/cpuidle/ sysfs access ********/

/*
 * helper function to read file from /sys into given buffer
 * fname is a relative path under "cpu/cpuidle/" dir
 */
static unsigned int sysfs_cpuidle_read_file(const char *fname, char *buf,
					    size_t buflen)
{
	char path[SYSFS_PATH_MAX];

	snprintf(path, sizeof(path), PATH_TO_CPU "cpuidle/%s", fname);

	return sysfs_read_file(path, buf, buflen);
}



/* read access to files which contain one string */

enum cpuidle_string {
	CPUIDLE_GOVERNOR,
	CPUIDLE_GOVERNOR_RO,
	CPUIDLE_DRIVER,
	MAX_CPUIDLE_STRING_FILES
};

static const char *cpuidle_string_files[MAX_CPUIDLE_STRING_FILES] = {
	[CPUIDLE_GOVERNOR]	= "current_governor",
	[CPUIDLE_GOVERNOR_RO]	= "current_governor_ro",
	[CPUIDLE_DRIVER]	= "current_driver",
};


static char * sysfs_cpuidle_get_one_string(enum cpuidle_string which)
{
	char linebuf[MAX_LINE_LEN];
	char *result;
	unsigned int len;

	if (which >= MAX_CPUIDLE_STRING_FILES)
		return NULL;

	if ( ( len = sysfs_cpuidle_read_file(cpuidle_string_files[which],
					    linebuf, sizeof(linebuf))) == 0 )
		return NULL;

	if ( ( result = strdup(linebuf) ) == NULL )
		return NULL;

	if (result[strlen(result) - 1] == '\n')
		result[strlen(result) - 1] = '\0';

	return result;
}

char * sysfs_get_cpuidle_governor(void)
{
	char *tmp = sysfs_cpuidle_get_one_string(CPUIDLE_GOVERNOR_RO);
	if (!tmp)
		return sysfs_cpuidle_get_one_string(CPUIDLE_GOVERNOR);
	else
		return tmp;
}

char * sysfs_get_cpuidle_driver(void)
{
	return sysfs_cpuidle_get_one_string(CPUIDLE_DRIVER);
}
/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */

/*
 * Get sched_mc or sched_smt settings
 * Pass "mc" or "smt" as argument
 *
 * Returns negative value on failure
 */
int sysfs_get_sched(const char* smt_mc)
{
 	unsigned long value;
	char linebuf[MAX_LINE_LEN];
	char *endp;
	char path[SYSFS_PATH_MAX];

	if (strcmp("mc", smt_mc) && strcmp("smt", smt_mc))
		return -EINVAL;

	snprintf(path, sizeof(path), PATH_TO_CPU "sched_%s_power_savings", smt_mc);
	if (sysfs_read_file(path, linebuf, MAX_LINE_LEN) == 0 )
		return -1;
	value = strtoul(linebuf, &endp, 0);
	if ( endp == linebuf || errno == ERANGE )
		return -1;
	return value;
}

/*
 * Get sched_mc or sched_smt settings
 * Pass "mc" or "smt" as argument
 *
 * Returns negative value on failure
 */
int sysfs_set_sched(const char* smt_mc, int val)
{
	char linebuf[MAX_LINE_LEN];
	char path[SYSFS_PATH_MAX];
	struct stat statbuf;

	if (strcmp("mc", smt_mc) && strcmp("smt", smt_mc))
		return -EINVAL;

	snprintf(path, sizeof(path), PATH_TO_CPU "sched_%s_power_savings", smt_mc);
	sprintf(linebuf, "%d", val);

	if ( stat(path, &statbuf) != 0 )
		return -ENODEV;

	if (sysfs_write_file(path, linebuf, MAX_LINE_LEN) == 0 )
		return -1;
	return 0;
}