linux/tools/power/cpupower/lib/sysfs.c

673 lines
14 KiB
C

/*
* (C) 2004-2009 Dominik Brodowski <linux@dominikbrodowski.de>
*
* Licensed under the terms of the GNU GPL License version 2.
*/
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "cpufreq.h"
#define PATH_TO_CPU "/sys/devices/system/cpu/"
#define MAX_LINE_LEN 4096
#define SYSFS_PATH_MAX 255
static unsigned int sysfs_read_file(const char *path, char *buf, size_t buflen)
{
int fd;
ssize_t numread;
fd = open(path, O_RDONLY);
if (fd == -1)
return 0;
numread = read(fd, buf, buflen - 1);
if (numread < 1) {
close(fd);
return 0;
}
buf[numread] = '\0';
close(fd);
return (unsigned int) numread;
}
/* CPUFREQ sysfs access **************************************************/
/* helper function to read file from /sys into given buffer */
/* fname is a relative path under "cpuX/cpufreq" dir */
static unsigned int sysfs_cpufreq_read_file(unsigned int cpu, const char *fname,
char *buf, size_t buflen)
{
char path[SYSFS_PATH_MAX];
snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpufreq/%s",
cpu, fname);
return sysfs_read_file(path, buf, buflen);
}
/* helper function to write a new value to a /sys file */
/* fname is a relative path under "cpuX/cpufreq" dir */
static unsigned int sysfs_cpufreq_write_file(unsigned int cpu,
const char *fname,
const char *value, size_t len)
{
char path[SYSFS_PATH_MAX];
int fd;
ssize_t numwrite;
snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpufreq/%s",
cpu, fname);
fd = open(path, O_WRONLY);
if (fd == -1)
return 0;
numwrite = write(fd, value, len);
if (numwrite < 1) {
close(fd);
return 0;
}
close(fd);
return (unsigned int) numwrite;
}
/* read access to files which contain one numeric value */
enum cpufreq_value {
CPUINFO_CUR_FREQ,
CPUINFO_MIN_FREQ,
CPUINFO_MAX_FREQ,
CPUINFO_LATENCY,
SCALING_CUR_FREQ,
SCALING_MIN_FREQ,
SCALING_MAX_FREQ,
STATS_NUM_TRANSITIONS,
MAX_CPUFREQ_VALUE_READ_FILES
};
static const char *cpufreq_value_files[MAX_CPUFREQ_VALUE_READ_FILES] = {
[CPUINFO_CUR_FREQ] = "cpuinfo_cur_freq",
[CPUINFO_MIN_FREQ] = "cpuinfo_min_freq",
[CPUINFO_MAX_FREQ] = "cpuinfo_max_freq",
[CPUINFO_LATENCY] = "cpuinfo_transition_latency",
[SCALING_CUR_FREQ] = "scaling_cur_freq",
[SCALING_MIN_FREQ] = "scaling_min_freq",
[SCALING_MAX_FREQ] = "scaling_max_freq",
[STATS_NUM_TRANSITIONS] = "stats/total_trans"
};
static unsigned long sysfs_cpufreq_get_one_value(unsigned int cpu,
enum cpufreq_value which)
{
unsigned long value;
unsigned int len;
char linebuf[MAX_LINE_LEN];
char *endp;
if (which >= MAX_CPUFREQ_VALUE_READ_FILES)
return 0;
len = sysfs_cpufreq_read_file(cpu, cpufreq_value_files[which],
linebuf, sizeof(linebuf));
if (len == 0)
return 0;
value = strtoul(linebuf, &endp, 0);
if (endp == linebuf || errno == ERANGE)
return 0;
return value;
}
/* read access to files which contain one string */
enum cpufreq_string {
SCALING_DRIVER,
SCALING_GOVERNOR,
MAX_CPUFREQ_STRING_FILES
};
static const char *cpufreq_string_files[MAX_CPUFREQ_STRING_FILES] = {
[SCALING_DRIVER] = "scaling_driver",
[SCALING_GOVERNOR] = "scaling_governor",
};
static char *sysfs_cpufreq_get_one_string(unsigned int cpu,
enum cpufreq_string which)
{
char linebuf[MAX_LINE_LEN];
char *result;
unsigned int len;
if (which >= MAX_CPUFREQ_STRING_FILES)
return NULL;
len = sysfs_cpufreq_read_file(cpu, cpufreq_string_files[which],
linebuf, sizeof(linebuf));
if (len == 0)
return NULL;
result = strdup(linebuf);
if (result == NULL)
return NULL;
if (result[strlen(result) - 1] == '\n')
result[strlen(result) - 1] = '\0';
return result;
}
/* write access */
enum cpufreq_write {
WRITE_SCALING_MIN_FREQ,
WRITE_SCALING_MAX_FREQ,
WRITE_SCALING_GOVERNOR,
WRITE_SCALING_SET_SPEED,
MAX_CPUFREQ_WRITE_FILES
};
static const char *cpufreq_write_files[MAX_CPUFREQ_WRITE_FILES] = {
[WRITE_SCALING_MIN_FREQ] = "scaling_min_freq",
[WRITE_SCALING_MAX_FREQ] = "scaling_max_freq",
[WRITE_SCALING_GOVERNOR] = "scaling_governor",
[WRITE_SCALING_SET_SPEED] = "scaling_setspeed",
};
static int sysfs_cpufreq_write_one_value(unsigned int cpu,
enum cpufreq_write which,
const char *new_value, size_t len)
{
if (which >= MAX_CPUFREQ_WRITE_FILES)
return 0;
if (sysfs_cpufreq_write_file(cpu, cpufreq_write_files[which],
new_value, len) != len)
return -ENODEV;
return 0;
};
unsigned long sysfs_get_freq_kernel(unsigned int cpu)
{
return sysfs_cpufreq_get_one_value(cpu, SCALING_CUR_FREQ);
}
unsigned long sysfs_get_freq_hardware(unsigned int cpu)
{
return sysfs_cpufreq_get_one_value(cpu, CPUINFO_CUR_FREQ);
}
unsigned long sysfs_get_freq_transition_latency(unsigned int cpu)
{
return sysfs_cpufreq_get_one_value(cpu, CPUINFO_LATENCY);
}
int sysfs_get_freq_hardware_limits(unsigned int cpu,
unsigned long *min,
unsigned long *max)
{
if ((!min) || (!max))
return -EINVAL;
*min = sysfs_cpufreq_get_one_value(cpu, CPUINFO_MIN_FREQ);
if (!*min)
return -ENODEV;
*max = sysfs_cpufreq_get_one_value(cpu, CPUINFO_MAX_FREQ);
if (!*max)
return -ENODEV;
return 0;
}
char *sysfs_get_freq_driver(unsigned int cpu)
{
return sysfs_cpufreq_get_one_string(cpu, SCALING_DRIVER);
}
struct cpufreq_policy *sysfs_get_freq_policy(unsigned int cpu)
{
struct cpufreq_policy *policy;
policy = malloc(sizeof(struct cpufreq_policy));
if (!policy)
return NULL;
policy->governor = sysfs_cpufreq_get_one_string(cpu, SCALING_GOVERNOR);
if (!policy->governor) {
free(policy);
return NULL;
}
policy->min = sysfs_cpufreq_get_one_value(cpu, SCALING_MIN_FREQ);
policy->max = sysfs_cpufreq_get_one_value(cpu, SCALING_MAX_FREQ);
if ((!policy->min) || (!policy->max)) {
free(policy->governor);
free(policy);
return NULL;
}
return policy;
}
struct cpufreq_available_governors *
sysfs_get_freq_available_governors(unsigned int cpu) {
struct cpufreq_available_governors *first = NULL;
struct cpufreq_available_governors *current = NULL;
char linebuf[MAX_LINE_LEN];
unsigned int pos, i;
unsigned int len;
len = sysfs_cpufreq_read_file(cpu, "scaling_available_governors",
linebuf, sizeof(linebuf));
if (len == 0)
return NULL;
pos = 0;
for (i = 0; i < len; i++) {
if (linebuf[i] == ' ' || linebuf[i] == '\n') {
if (i - pos < 2)
continue;
if (current) {
current->next = malloc(sizeof(*current));
if (!current->next)
goto error_out;
current = current->next;
} else {
first = malloc(sizeof(*first));
if (!first)
goto error_out;
current = first;
}
current->first = first;
current->next = NULL;
current->governor = malloc(i - pos + 1);
if (!current->governor)
goto error_out;
memcpy(current->governor, linebuf + pos, i - pos);
current->governor[i - pos] = '\0';
pos = i + 1;
}
}
return first;
error_out:
while (first) {
current = first->next;
if (first->governor)
free(first->governor);
free(first);
first = current;
}
return NULL;
}
struct cpufreq_available_frequencies *
sysfs_get_available_frequencies(unsigned int cpu) {
struct cpufreq_available_frequencies *first = NULL;
struct cpufreq_available_frequencies *current = NULL;
char one_value[SYSFS_PATH_MAX];
char linebuf[MAX_LINE_LEN];
unsigned int pos, i;
unsigned int len;
len = sysfs_cpufreq_read_file(cpu, "scaling_available_frequencies",
linebuf, sizeof(linebuf));
if (len == 0)
return NULL;
pos = 0;
for (i = 0; i < len; i++) {
if (linebuf[i] == ' ' || linebuf[i] == '\n') {
if (i - pos < 2)
continue;
if (i - pos >= SYSFS_PATH_MAX)
goto error_out;
if (current) {
current->next = malloc(sizeof(*current));
if (!current->next)
goto error_out;
current = current->next;
} else {
first = malloc(sizeof(*first));
if (!first)
goto error_out;
current = first;
}
current->first = first;
current->next = NULL;
memcpy(one_value, linebuf + pos, i - pos);
one_value[i - pos] = '\0';
if (sscanf(one_value, "%lu", &current->frequency) != 1)
goto error_out;
pos = i + 1;
}
}
return first;
error_out:
while (first) {
current = first->next;
free(first);
first = current;
}
return NULL;
}
static struct cpufreq_affected_cpus *sysfs_get_cpu_list(unsigned int cpu,
const char *file)
{
struct cpufreq_affected_cpus *first = NULL;
struct cpufreq_affected_cpus *current = NULL;
char one_value[SYSFS_PATH_MAX];
char linebuf[MAX_LINE_LEN];
unsigned int pos, i;
unsigned int len;
len = sysfs_cpufreq_read_file(cpu, file, linebuf, sizeof(linebuf));
if (len == 0)
return NULL;
pos = 0;
for (i = 0; i < len; i++) {
if (i == len || linebuf[i] == ' ' || linebuf[i] == '\n') {
if (i - pos < 1)
continue;
if (i - pos >= SYSFS_PATH_MAX)
goto error_out;
if (current) {
current->next = malloc(sizeof(*current));
if (!current->next)
goto error_out;
current = current->next;
} else {
first = malloc(sizeof(*first));
if (!first)
goto error_out;
current = first;
}
current->first = first;
current->next = NULL;
memcpy(one_value, linebuf + pos, i - pos);
one_value[i - pos] = '\0';
if (sscanf(one_value, "%u", &current->cpu) != 1)
goto error_out;
pos = i + 1;
}
}
return first;
error_out:
while (first) {
current = first->next;
free(first);
first = current;
}
return NULL;
}
struct cpufreq_affected_cpus *sysfs_get_freq_affected_cpus(unsigned int cpu)
{
return sysfs_get_cpu_list(cpu, "affected_cpus");
}
struct cpufreq_affected_cpus *sysfs_get_freq_related_cpus(unsigned int cpu)
{
return sysfs_get_cpu_list(cpu, "related_cpus");
}
struct cpufreq_stats *sysfs_get_freq_stats(unsigned int cpu,
unsigned long long *total_time) {
struct cpufreq_stats *first = NULL;
struct cpufreq_stats *current = NULL;
char one_value[SYSFS_PATH_MAX];
char linebuf[MAX_LINE_LEN];
unsigned int pos, i;
unsigned int len;
len = sysfs_cpufreq_read_file(cpu, "stats/time_in_state",
linebuf, sizeof(linebuf));
if (len == 0)
return NULL;
*total_time = 0;
pos = 0;
for (i = 0; i < len; i++) {
if (i == strlen(linebuf) || linebuf[i] == '\n') {
if (i - pos < 2)
continue;
if ((i - pos) >= SYSFS_PATH_MAX)
goto error_out;
if (current) {
current->next = malloc(sizeof(*current));
if (!current->next)
goto error_out;
current = current->next;
} else {
first = malloc(sizeof(*first));
if (!first)
goto error_out;
current = first;
}
current->first = first;
current->next = NULL;
memcpy(one_value, linebuf + pos, i - pos);
one_value[i - pos] = '\0';
if (sscanf(one_value, "%lu %llu",
&current->frequency,
&current->time_in_state) != 2)
goto error_out;
*total_time = *total_time + current->time_in_state;
pos = i + 1;
}
}
return first;
error_out:
while (first) {
current = first->next;
free(first);
first = current;
}
return NULL;
}
unsigned long sysfs_get_freq_transitions(unsigned int cpu)
{
return sysfs_cpufreq_get_one_value(cpu, STATS_NUM_TRANSITIONS);
}
static int verify_gov(char *new_gov, char *passed_gov)
{
unsigned int i, j = 0;
if (!passed_gov || (strlen(passed_gov) > 19))
return -EINVAL;
strncpy(new_gov, passed_gov, 20);
for (i = 0; i < 20; i++) {
if (j) {
new_gov[i] = '\0';
continue;
}
if ((new_gov[i] >= 'a') && (new_gov[i] <= 'z'))
continue;
if ((new_gov[i] >= 'A') && (new_gov[i] <= 'Z'))
continue;
if (new_gov[i] == '-')
continue;
if (new_gov[i] == '_')
continue;
if (new_gov[i] == '\0') {
j = 1;
continue;
}
return -EINVAL;
}
new_gov[19] = '\0';
return 0;
}
int sysfs_modify_freq_policy_governor(unsigned int cpu, char *governor)
{
char new_gov[SYSFS_PATH_MAX];
if (!governor)
return -EINVAL;
if (verify_gov(new_gov, governor))
return -EINVAL;
return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_GOVERNOR,
new_gov, strlen(new_gov));
};
int sysfs_modify_freq_policy_max(unsigned int cpu, unsigned long max_freq)
{
char value[SYSFS_PATH_MAX];
snprintf(value, SYSFS_PATH_MAX, "%lu", max_freq);
return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MAX_FREQ,
value, strlen(value));
};
int sysfs_modify_freq_policy_min(unsigned int cpu, unsigned long min_freq)
{
char value[SYSFS_PATH_MAX];
snprintf(value, SYSFS_PATH_MAX, "%lu", min_freq);
return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MIN_FREQ,
value, strlen(value));
};
int sysfs_set_freq_policy(unsigned int cpu, struct cpufreq_policy *policy)
{
char min[SYSFS_PATH_MAX];
char max[SYSFS_PATH_MAX];
char gov[SYSFS_PATH_MAX];
int ret;
unsigned long old_min;
int write_max_first;
if (!policy || !(policy->governor))
return -EINVAL;
if (policy->max < policy->min)
return -EINVAL;
if (verify_gov(gov, policy->governor))
return -EINVAL;
snprintf(min, SYSFS_PATH_MAX, "%lu", policy->min);
snprintf(max, SYSFS_PATH_MAX, "%lu", policy->max);
old_min = sysfs_cpufreq_get_one_value(cpu, SCALING_MIN_FREQ);
write_max_first = (old_min && (policy->max < old_min) ? 0 : 1);
if (write_max_first) {
ret = sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MAX_FREQ,
max, strlen(max));
if (ret)
return ret;
}
ret = sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MIN_FREQ, min,
strlen(min));
if (ret)
return ret;
if (!write_max_first) {
ret = sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_MAX_FREQ,
max, strlen(max));
if (ret)
return ret;
}
return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_GOVERNOR,
gov, strlen(gov));
}
int sysfs_set_frequency(unsigned int cpu, unsigned long target_frequency)
{
struct cpufreq_policy *pol = sysfs_get_freq_policy(cpu);
char userspace_gov[] = "userspace";
char freq[SYSFS_PATH_MAX];
int ret;
if (!pol)
return -ENODEV;
if (strncmp(pol->governor, userspace_gov, 9) != 0) {
ret = sysfs_modify_freq_policy_governor(cpu, userspace_gov);
if (ret) {
cpufreq_put_policy(pol);
return ret;
}
}
cpufreq_put_policy(pol);
snprintf(freq, SYSFS_PATH_MAX, "%lu", target_frequency);
return sysfs_cpufreq_write_one_value(cpu, WRITE_SCALING_SET_SPEED,
freq, strlen(freq));
}
/* CPUFREQ sysfs access **************************************************/
/* General sysfs access **************************************************/
int sysfs_cpu_exists(unsigned int cpu)
{
char file[SYSFS_PATH_MAX];
struct stat statbuf;
snprintf(file, SYSFS_PATH_MAX, PATH_TO_CPU "cpu%u/", cpu);
if (stat(file, &statbuf) != 0)
return -ENOSYS;
return S_ISDIR(statbuf.st_mode) ? 0 : -ENOSYS;
}
/* General sysfs access **************************************************/