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-rw-r--r--tools/power/cpupower/debug/i386/powernow-k8-decode.c95
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 000000000..735dca1e2
--- /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;
+}