LXR linux/tools/power/cpupower/debug/i386/powernow-k8-decode.c

   1/*
   2 *  (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
   3 *
   4 *  Licensed under the terms of the GNU GPL License version 2.
   5 *
   6 * Based on code found in
   7 * linux/arch/i386/kernel/cpu/cpufreq/powernow-k8.c
   8 * and originally developed by Paul Devriendt
   9 */
  10
  11#include <stdio.h>
  12#include <stdlib.h>
  13#include <stdint.h>
  14#include <unistd.h>
  15#include <errno.h>
  16#include <fcntl.h>
  17
  18#include <sys/types.h>
  19#include <sys/stat.h>
  20
  21#define MCPU 32
  22
  23#define MSR_FIDVID_STATUS       0xc0010042
  24
  25#define MSR_S_HI_CURRENT_VID    0x0000001f
  26#define MSR_S_LO_CURRENT_FID    0x0000003f
  27
  28static int get_fidvid(uint32_t cpu, uint32_t *fid, uint32_t *vid)
  29{
  30        int err = 1;
  31        uint64_t msr = 0;
  32        int fd;
  33        char file[20];
  34
  35        if (cpu > MCPU)
  36                goto out;
  37
  38        sprintf(file, "/dev/cpu/%d/msr", cpu);
  39
  40        fd = open(file, O_RDONLY);
  41        if (fd < 0)
  42                goto out;
  43        lseek(fd, MSR_FIDVID_STATUS, SEEK_CUR);
  44        if (read(fd, &msr, 8) != 8)
  45                goto err1;
  46
  47        *fid = ((uint32_t )(msr & 0xffffffffull)) & MSR_S_LO_CURRENT_FID;
  48        *vid = ((uint32_t )(msr>>32 & 0xffffffffull)) & MSR_S_HI_CURRENT_VID;
  49        err = 0;
  50err1:
  51        close(fd);
  52out:
  53        return err;
  54}
  55
  56
  57/* Return a frequency in MHz, given an input fid */
  58static uint32_t find_freq_from_fid(uint32_t fid)
  59{
  60        return 800 + (fid * 100);
  61}
  62
  63/* Return a voltage in miliVolts, given an input vid */
  64static uint32_t find_millivolts_from_vid(uint32_t vid)
  65{
  66        return 1550-vid*25;
  67}
  68
  69int main (int argc, char *argv[])
  70{
  71        int err;
  72        int cpu;
  73        uint32_t fid, vid;
  74
  75        if (argc < 2)
  76                cpu = 0;
  77        else
  78                cpu = strtoul(argv[1], NULL, 0);
  79
  80        err = get_fidvid(cpu, &fid, &vid);
  81
  82        if (err) {
  83                printf("can't get fid, vid from MSR\n");
  84                printf("Possible trouble: you don't run a powernow-k8 capable cpu\n");
  85                printf("or you are not root, or the msr driver is not present\n");
  86                exit(1);
  87        }
  88
  89        
  90        printf("cpu %d currently at %d MHz and %d mV\n",
  91                        cpu,
  92                        find_freq_from_fid(fid),
  93                        find_millivolts_from_vid(vid));
  94        
  95        return 0;
  96}
  97