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;
+}