diff options
Diffstat (limited to 'tools/power/cpupower/debug/i386/powernow-k8-decode.c')
-rw-r--r-- | tools/power/cpupower/debug/i386/powernow-k8-decode.c | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/tools/power/cpupower/debug/i386/powernow-k8-decode.c b/tools/power/cpupower/debug/i386/powernow-k8-decode.c new file mode 100644 index 0000000000..735dca1e25 --- /dev/null +++ b/tools/power/cpupower/debug/i386/powernow-k8-decode.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * (C) 2004 Bruno Ducrot <ducrot@poupinou.org> + * + * Based on code found in + * linux/arch/i386/kernel/cpu/cpufreq/powernow-k8.c + * and originally developed by Paul Devriendt + */ + +#include <stdio.h> +#include <stdlib.h> +#include <stdint.h> +#include <unistd.h> +#include <errno.h> +#include <fcntl.h> + +#include <sys/types.h> +#include <sys/stat.h> + +#define MCPU 32 + +#define MSR_FIDVID_STATUS 0xc0010042 + +#define MSR_S_HI_CURRENT_VID 0x0000001f +#define MSR_S_LO_CURRENT_FID 0x0000003f + +static int get_fidvid(uint32_t cpu, uint32_t *fid, uint32_t *vid) +{ + int err = 1; + uint64_t msr = 0; + int fd; + char file[20]; + + if (cpu > MCPU) + goto out; + + sprintf(file, "/dev/cpu/%d/msr", cpu); + + fd = open(file, O_RDONLY); + if (fd < 0) + goto out; + lseek(fd, MSR_FIDVID_STATUS, SEEK_CUR); + if (read(fd, &msr, 8) != 8) + goto err1; + + *fid = ((uint32_t )(msr & 0xffffffffull)) & MSR_S_LO_CURRENT_FID; + *vid = ((uint32_t )(msr>>32 & 0xffffffffull)) & MSR_S_HI_CURRENT_VID; + err = 0; +err1: + close(fd); +out: + return err; +} + + +/* Return a frequency in MHz, given an input fid */ +static uint32_t find_freq_from_fid(uint32_t fid) +{ + return 800 + (fid * 100); +} + +/* Return a voltage in miliVolts, given an input vid */ +static uint32_t find_millivolts_from_vid(uint32_t vid) +{ + return 1550-vid*25; +} + +int main (int argc, char *argv[]) +{ + int err; + int cpu; + uint32_t fid, vid; + + if (argc < 2) + cpu = 0; + else + cpu = strtoul(argv[1], NULL, 0); + + err = get_fidvid(cpu, &fid, &vid); + + if (err) { + printf("can't get fid, vid from MSR\n"); + printf("Possible trouble: you don't run a powernow-k8 capable cpu\n"); + printf("or you are not root, or the msr driver is not present\n"); + exit(1); + } + + + printf("cpu %d currently at %d MHz and %d mV\n", + cpu, + find_freq_from_fid(fid), + find_millivolts_from_vid(vid)); + + return 0; +} |