New patch to review for coreboot: cpu/amd/fam10h-15h: Add tsc_freq_mhz() function

[Timothy Pearson]

Timothy Pearson ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/12834

-gerrit

commit 15aa2536f51808faece445b0c19955fd0d128fae
Author: Timothy Pearson 
Date:   Tue Jan 5 11:00:49 2016 -0600

cpu/amd/fam10h-15h: Add tsc_freq_mhz() function

The AMD Family 10h/15h processors use a TSC that increments at
    the P0 core frequency.  Allow coreboot to query the TSC frequency.

Change-Id: I73ead4fd4af18991452d59985b667a54689778cd
    Signed-off-by: Timothy Pearson 
---
 src/cpu/amd/family_10h-family_15h/Makefile.inc |  1 +
 src/cpu/amd/family_10h-family_15h/tsc_freq.c   | 31 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/src/cpu/amd/family_10h-family_15h/Makefile.inc b/src/cpu/amd/family_10h-family_15h/Makefile.inc
index 6cd2513..0f31b79 100644
--- a/src/cpu/amd/family_10h-family_15h/Makefile.inc
+++ b/src/cpu/amd/family_10h-family_15h/Makefile.inc
@@ -5,6 +5,7 @@ ramstage-y += processor_name.c
 romstage-y += update_microcode.c
 romstage-y += ram_calc.c
 ramstage-y += ram_calc.c
+ramstage-y += tsc_freq.c
 ramstage-y += monotonic_timer.c
 ramstage-$(CONFIG_HAVE_ACPI_TABLES) += powernow_acpi.c

diff --git a/src/cpu/amd/family_10h-family_15h/tsc_freq.c b/src/cpu/amd/family_10h-family_15h/tsc_freq.c
new file mode 100644
index 0000000..2bd6368
--- /dev/null
+++ b/src/cpu/amd/family_10h-family_15h/tsc_freq.c
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2015 Raptor Engineeirng
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <stdint.h>
+#include <cpu/x86/msr.h>
+#include <cpu/x86/tsc.h>
+
+unsigned long tsc_freq_mhz(void)
+{
+	msr_t msr;
+	uint8_t cpufid;
+	uint8_t cpudid;
+
+	msr = rdmsr(0xc0010064);
+	cpufid = (msr.lo & 0x3f);
+	cpudid = (msr.lo & 0x1c0) >> 6;
+
+	return (100 * (cpufid + 0x10)) / (0x01 << cpudid);
+}