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-rw-r--r--tools/power/cpupower/utils/helpers/sysfs.c350
1 files changed, 350 insertions, 0 deletions
diff --git a/tools/power/cpupower/utils/helpers/sysfs.c b/tools/power/cpupower/utils/helpers/sysfs.c
new file mode 100644
index 00000000000..0c534e79652
--- /dev/null
+++ b/tools/power/cpupower/utils/helpers/sysfs.c
@@ -0,0 +1,350 @@
+/*
+ * (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;
+}
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