1 files changed, 68 insertions, 0 deletions
diff --git a/src/northbridge/intel/fsp_rangeley/udelay.c b/src/northbridge/intel/fsp_rangeley/udelay.c
new file mode 100644
index 0000000000..2256208d06
--- /dev/null
+++ b/src/northbridge/intel/fsp_rangeley/udelay.c
@@ -0,0 +1,68 @@
+/*
+ * 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 Rangeley CPUs always run the TSC at BCLK=100MHz
+ */
+
+/* Simple 32- to 64-bit multiplication. Uses 16-bit words to avoid overflow.
+ * This code is used to prevent use of libgcc's umoddi3.
+ */
+static inline void multiply_to_tsc(tsc_t *const tsc, const u32 a, const u32 b)
+{
+	tsc->lo = (a & 0xffff) * (b & 0xffff);
+	tsc->hi = ((tsc->lo >> 16)
+		+ ((a & 0xffff) * (b >> 16))
+		+ ((b & 0xffff) * (a >> 16)));
+	tsc->lo = ((tsc->hi & 0xffff) << 16) | (tsc->lo & 0xffff);
+	tsc->hi = ((a >> 16) * (b >> 16)) + (tsc->hi >> 16);
+}
+
+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;
+	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)));
+}