60 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2 3#include <stdio.h>4#include <errno.h>5#include <stdlib.h>6#include <string.h>7#include <sys/types.h>8#include <sys/stat.h>9#include <fcntl.h>10#include <unistd.h>11 12#include "cpupower_intern.h"13#include "acpi_cppc.h"14 15/* ACPI CPPC sysfs access ***********************************************/16 17static int acpi_cppc_read_file(unsigned int cpu, const char *fname,18 char *buf, size_t buflen)19{20 char path[SYSFS_PATH_MAX];21 22 snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/acpi_cppc/%s",23 cpu, fname);24 return cpupower_read_sysfs(path, buf, buflen);25}26 27static const char * const acpi_cppc_value_files[] = {28 [HIGHEST_PERF] = "highest_perf",29 [LOWEST_PERF] = "lowest_perf",30 [NOMINAL_PERF] = "nominal_perf",31 [LOWEST_NONLINEAR_PERF] = "lowest_nonlinear_perf",32 [LOWEST_FREQ] = "lowest_freq",33 [NOMINAL_FREQ] = "nominal_freq",34 [REFERENCE_PERF] = "reference_perf",35 [WRAPAROUND_TIME] = "wraparound_time"36};37 38unsigned long acpi_cppc_get_data(unsigned int cpu, enum acpi_cppc_value which)39{40 unsigned long long value;41 unsigned int len;42 char linebuf[MAX_LINE_LEN];43 char *endp;44 45 if (which >= MAX_CPPC_VALUE_FILES)46 return 0;47 48 len = acpi_cppc_read_file(cpu, acpi_cppc_value_files[which],49 linebuf, sizeof(linebuf));50 if (len == 0)51 return 0;52 53 value = strtoull(linebuf, &endp, 0);54 55 if (endp == linebuf || errno == ERANGE)56 return 0;57 58 return value;59}60