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-rw-r--r--src/northbridge/intel/sandybridge/Makefile.inc1
-rw-r--r--src/northbridge/intel/sandybridge/udelay.c55
2 files changed, 56 insertions, 0 deletions
diff --git a/src/northbridge/intel/sandybridge/Makefile.inc b/src/northbridge/intel/sandybridge/Makefile.inc
index 60765f2da1..cf79459df2 100644
--- a/src/northbridge/intel/sandybridge/Makefile.inc
+++ b/src/northbridge/intel/sandybridge/Makefile.inc
@@ -42,6 +42,7 @@ romstage-y += early_init.c
romstage-y += report_platform.c
romstage-y += ../../../arch/x86/lib/walkcbfs.S
+smm-$(CONFIG_HAVE_SMI_HANDLER) += udelay.c
smm-$(CONFIG_HAVE_SMI_HANDLER) += finalize.c
# We don't ship that, but booting without it is bound to fail
diff --git a/src/northbridge/intel/sandybridge/udelay.c b/src/northbridge/intel/sandybridge/udelay.c
new file mode 100644
index 0000000000..b150253247
--- /dev/null
+++ b/src/northbridge/intel/sandybridge/udelay.c
@@ -0,0 +1,55 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2007-2008 coresystems GmbH
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc.
+ */
+
+#include <delay.h>
+#include <stdint.h>
+#include <cpu/x86/tsc.h>
+#include <cpu/x86/msr.h>
+
+/**
+ * Intel Sandy Bridge/Ivy Bridge CPUs always run the TSC at BCLK=100MHz
+ */
+
+void udelay(u32 us)
+{
+ u32 dword;
+ tsc_t tsc, tsc1, tscd;
+ msr_t msr;
+ u32 fsb = 100, divisor;
+ u32 d; /* ticks per us */
+
+ msr = rdmsr(0xce);
+ divisor = (msr.lo >> 8) & 0xff;
+
+ d = fsb * divisor; /* On Core/Core2 this is divided by 4 */
+ multiply_to_tsc(&tscd, us, d);
+
+ tsc1 = rdtsc();
+ dword = tsc1.lo + tscd.lo;
+ if ((dword < tsc1.lo) || (dword < tscd.lo)) {
+ tsc1.hi++;
+ }
+ tsc1.lo = dword;
+ tsc1.hi += tscd.hi;
+
+ do {
+ tsc = rdtsc();
+ } while ((tsc.hi < tsc1.hi)
+ || ((tsc.hi == tsc1.hi) && (tsc.lo < tsc1.lo)));
+}