diff options
Diffstat (limited to 'tools/power/cpupower/lib/sysfs.c')
| -rw-r--r-- | tools/power/cpupower/lib/sysfs.c | 671 |
1 files changed, 671 insertions, 0 deletions
diff --git a/tools/power/cpupower/lib/sysfs.c b/tools/power/cpupower/lib/sysfs.c new file mode 100644 index 00000000000..c9b061fe87b --- /dev/null +++ b/tools/power/cpupower/lib/sysfs.c @@ -0,0 +1,671 @@ +/* + * (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 255 +#define SYSFS_PATH_MAX 255 + + +static 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; +} + + +/* 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; + size_t numwrite; + + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpufreq/%s", + cpu, fname); + + 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; +} + +/* 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; + + if ( ( len = sysfs_cpufreq_read_file(cpu, cpufreq_value_files[which], + linebuf, sizeof(linebuf))) == 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; + + if ( ( len = sysfs_cpufreq_read_file(cpu, cpufreq_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; +} + +/* 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; + + if ( ( len = sysfs_cpufreq_read_file(cpu, "scaling_available_governors", + linebuf, sizeof(linebuf))) == 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; + + if ( ( len = sysfs_cpufreq_read_file(cpu, + "scaling_available_frequencies", + linebuf, sizeof(linebuf))) == 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", ¤t->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; + + if ( ( len = sysfs_cpufreq_read_file(cpu, file, linebuf, + sizeof(linebuf))) == 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", ¤t->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; + + if ( ( len = sysfs_cpufreq_read_file(cpu, "stats/time_in_state", + linebuf, sizeof(linebuf))) == 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", ¤t->frequency, ¤t->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 **************************************************/ |