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Diffstat (limited to 'tools/power/cpupower/lib/sysfs.c')
-rw-r--r--tools/power/cpupower/lib/sysfs.c672
1 files changed, 672 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..870713a75a8
--- /dev/null
+++ b/tools/power/cpupower/lib/sysfs.c
@@ -0,0 +1,672 @@
+/*
+ * (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 **************************************************/
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-18 08:49:58 +0000