// SPDX-License-Identifier: GPL-2.0-only

#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 "cpupower_intern.h"
#include "acpi_cppc.h"

/* ACPI CPPC sysfs access ***********************************************/

static int acpi_cppc_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/acpi_cppc/%s",
                 cpu, fname);
        return cpupower_read_sysfs(path, buf, buflen);
}

static const char * const acpi_cppc_value_files[] = {
        [HIGHEST_PERF] = "highest_perf",
        [LOWEST_PERF] = "lowest_perf",
        [NOMINAL_PERF] = "nominal_perf",
        [LOWEST_NONLINEAR_PERF] = "lowest_nonlinear_perf",
        [LOWEST_FREQ] = "lowest_freq",
        [NOMINAL_FREQ] = "nominal_freq",
        [REFERENCE_PERF] = "reference_perf",
        [WRAPAROUND_TIME] = "wraparound_time"
};

unsigned long acpi_cppc_get_data(unsigned int cpu, enum acpi_cppc_value which)
{
        unsigned long long value;
        unsigned int len;
        char linebuf[MAX_LINE_LEN];
        char *endp;

        if (which >= MAX_CPPC_VALUE_FILES)
                return 0;

        len = acpi_cppc_read_file(cpu, acpi_cppc_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;
}