From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- tools/power/cpupower/utils/helpers/sysfs.c | 472 +++++++++++++++++++++++++++++ 1 file changed, 472 insertions(+) create mode 100644 tools/power/cpupower/utils/helpers/sysfs.c (limited to 'tools/power/cpupower/utils/helpers/sysfs.c') diff --git a/tools/power/cpupower/utils/helpers/sysfs.c b/tools/power/cpupower/utils/helpers/sysfs.c new file mode 100644 index 000000000..4e8fe2c7b --- /dev/null +++ b/tools/power/cpupower/utils/helpers/sysfs.c @@ -0,0 +1,472 @@ +/* + * (C) 2004-2009 Dominik Brodowski + * (C) 2011 Thomas Renninger Novell Inc. + * + * Licensed under the terms of the GNU GPL License version 2. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "helpers/sysfs.h" + +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; +} + +/* + * Detect whether a CPU is online + * + * Returns: + * 1 -> if CPU is online + * 0 -> if CPU is offline + * negative errno values in error case + */ +int sysfs_is_cpu_online(unsigned int cpu) +{ + char path[SYSFS_PATH_MAX]; + int fd; + ssize_t numread; + unsigned long long value; + char linebuf[MAX_LINE_LEN]; + char *endp; + struct stat statbuf; + + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u", cpu); + + if (stat(path, &statbuf) != 0) + return 0; + + /* + * kernel without CONFIG_HOTPLUG_CPU + * -> cpuX directory exists, but not cpuX/online file + */ + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/online", cpu); + if (stat(path, &statbuf) != 0) + return 1; + + fd = open(path, O_RDONLY); + if (fd == -1) + return -errno; + + numread = read(fd, linebuf, MAX_LINE_LEN - 1); + if (numread < 1) { + close(fd); + return -EIO; + } + linebuf[numread] = '\0'; + close(fd); + + value = strtoull(linebuf, &endp, 0); + if (value > 1) + return -EINVAL; + + return value; +} + +/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */ + + +/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */ + +/* + * helper function to check whether a file under "../cpuX/cpuidle/stateX/" dir + * exists. + * For example the functionality to disable c-states was introduced in later + * kernel versions, this function can be used to explicitly check for this + * feature. + * + * returns 1 if the file exists, 0 otherwise. + */ +unsigned int sysfs_idlestate_file_exists(unsigned int cpu, + unsigned int idlestate, + const char *fname) +{ + char path[SYSFS_PATH_MAX]; + struct stat statbuf; + + + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s", + cpu, idlestate, fname); + if (stat(path, &statbuf) != 0) + return 0; + return 1; +} + +/* + * 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; + ssize_t numread; + + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/cpuidle/state%u/%s", + cpu, idlestate, fname); + + 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; +} + +/* + * helper function to write a new value to a /sys file + * fname is a relative path under "../cpuX/cpuidle/cstateY/" dir + * + * Returns the number of bytes written or 0 on error + */ +static +unsigned int sysfs_idlestate_write_file(unsigned int cpu, + unsigned int idlestate, + 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/cpuidle/state%u/%s", + cpu, idlestate, 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 idlestate_value { + IDLESTATE_USAGE, + IDLESTATE_POWER, + IDLESTATE_LATENCY, + IDLESTATE_TIME, + IDLESTATE_DISABLE, + 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", + [IDLESTATE_DISABLE] = "disable", +}; + +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; + + len = sysfs_idlestate_read_file(cpu, idlestate, + idlestate_value_files[which], + linebuf, sizeof(linebuf)); + if (len == 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; + + len = sysfs_idlestate_read_file(cpu, idlestate, + idlestate_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; +} + +/* + * Returns: + * 1 if disabled + * 0 if enabled + * -1 if idlestate is not available + * -2 if disabling is not supported by the kernel + */ +int sysfs_is_idlestate_disabled(unsigned int cpu, + unsigned int idlestate) +{ + if (sysfs_get_idlestate_count(cpu) <= idlestate) + return -1; + + if (!sysfs_idlestate_file_exists(cpu, idlestate, + idlestate_value_files[IDLESTATE_DISABLE])) + return -2; + return sysfs_idlestate_get_one_value(cpu, idlestate, IDLESTATE_DISABLE); +} + +/* + * Pass 1 as last argument to disable or 0 to enable the state + * Returns: + * 0 on success + * negative values on error, for example: + * -1 if idlestate is not available + * -2 if disabling is not supported by the kernel + * -3 No write access to disable/enable C-states + */ +int sysfs_idlestate_disable(unsigned int cpu, + unsigned int idlestate, + unsigned int disable) +{ + char value[SYSFS_PATH_MAX]; + int bytes_written; + + if (sysfs_get_idlestate_count(cpu) <= idlestate) + return -1; + + if (!sysfs_idlestate_file_exists(cpu, idlestate, + idlestate_value_files[IDLESTATE_DISABLE])) + return -2; + + snprintf(value, SYSFS_PATH_MAX, "%u", disable); + + bytes_written = sysfs_idlestate_write_file(cpu, idlestate, "disable", + value, sizeof(disable)); + if (bytes_written) + return 0; + return -3; +} + +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 + */ +unsigned 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 0; + + 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; + + len = sysfs_cpuidle_read_file(cpuidle_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; +} + +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) +{ + return -ENODEV; +} + +/* + * 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) +{ + return -ENODEV; +} -- cgit v1.2.3-54-g00ecf