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-rw-r--r--tools/power/cpupower/debug/i386/centrino-decode.c112
1 files changed, 112 insertions, 0 deletions
diff --git a/tools/power/cpupower/debug/i386/centrino-decode.c b/tools/power/cpupower/debug/i386/centrino-decode.c
new file mode 100644
index 000000000..700cd31a7
--- /dev/null
+++ b/tools/power/cpupower/debug/i386/centrino-decode.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * (C) 2003 - 2004 Dominik Brodowski <linux@dominikbrodowski.de>
+ *
+ * Based on code found in
+ * linux/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
+ * and originally developed by Jeremy Fitzhardinge.
+ *
+ * USAGE: simply run it to decode the current settings on CPU 0,
+ * or pass the CPU number as argument, or pass the MSR content
+ * as argument.
+ */
+
+#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_IA32_PERF_STATUS 0x198
+
+static int rdmsr(unsigned int cpu, unsigned int msr,
+ unsigned int *lo, unsigned int *hi)
+{
+ int fd;
+ char file[20];
+ unsigned long long val;
+ int retval = -1;
+
+ *lo = *hi = 0;
+
+ if (cpu > MCPU)
+ goto err1;
+
+ sprintf(file, "/dev/cpu/%d/msr", cpu);
+ fd = open(file, O_RDONLY);
+
+ if (fd < 0)
+ goto err1;
+
+ if (lseek(fd, msr, SEEK_CUR) == -1)
+ goto err2;
+
+ if (read(fd, &val, 8) != 8)
+ goto err2;
+
+ *lo = (uint32_t )(val & 0xffffffffull);
+ *hi = (uint32_t )(val>>32 & 0xffffffffull);
+
+ retval = 0;
+err2:
+ close(fd);
+err1:
+ return retval;
+}
+
+static void decode (unsigned int msr)
+{
+ unsigned int multiplier;
+ unsigned int mv;
+
+ multiplier = ((msr >> 8) & 0xFF);
+
+ mv = (((msr & 0xFF) * 16) + 700);
+
+ printf("0x%x means multiplier %d @ %d mV\n", msr, multiplier, mv);
+}
+
+static int decode_live(unsigned int cpu)
+{
+ unsigned int lo, hi;
+ int err;
+
+ err = rdmsr(cpu, MSR_IA32_PERF_STATUS, &lo, &hi);
+
+ if (err) {
+ printf("can't get MSR_IA32_PERF_STATUS for cpu %d\n", cpu);
+ printf("Possible trouble: you don't run an Enhanced SpeedStep capable cpu\n");
+ printf("or you are not root, or the msr driver is not present\n");
+ return 1;
+ }
+
+ decode(lo);
+
+ return 0;
+}
+
+int main (int argc, char **argv)
+{
+ unsigned int cpu, mode = 0;
+
+ if (argc < 2)
+ cpu = 0;
+ else {
+ cpu = strtoul(argv[1], NULL, 0);
+ if (cpu >= MCPU)
+ mode = 1;
+ }
+
+ if (mode)
+ decode(cpu);
+ else
+ decode_live(cpu);
+
+ return 0;
+}