1 files changed, 88 insertions, 0 deletions
diff --git a/arch/powerpc/boot/util.S b/arch/powerpc/boot/util.S
new file mode 100644
index 00000000000..427ddfc1199
--- /dev/null
+++ b/arch/powerpc/boot/util.S
@@ -0,0 +1,88 @@
+/*
+ * Copied from <file:arch/powerpc/kernel/misc_32.S>
+ *
+ * This file contains miscellaneous low-level functions.
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ * Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
+ * and Paul Mackerras.
+ *
+ * kexec bits:
+ * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
+ * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+#include "ppc_asm.h"
+
+#define SPRN_PVR        0x11F   /* Processor Version Register */
+
+	.text
+
+/* udelay (on non-601 processors) needs to know the period of the
+ * timebase in nanoseconds.  This used to be hardcoded to be 60ns
+ * (period of 66MHz/4).  Now a variable is used that is initialized to
+ * 60 for backward compatibility, but it can be overridden as necessary
+ * with code something like this:
+ *    extern unsigned long timebase_period_ns;
+ *    timebase_period_ns = 1000000000 / bd->bi_tbfreq;
+ */
+	.data
+	.globl timebase_period_ns
+timebase_period_ns:
+	.long	60
+
+	.text
+/*
+ * Delay for a number of microseconds
+ */
+	.globl	udelay
+udelay:
+	mfspr	r4,SPRN_PVR
+	srwi	r4,r4,16
+	cmpwi	0,r4,1		/* 601 ? */
+	bne	.udelay_not_601
+00:	li	r0,86	/* Instructions / microsecond? */
+	mtctr	r0
+10:	addi	r0,r0,0 /* NOP */
+	bdnz	10b
+	subic.	r3,r3,1
+	bne	00b
+	blr
+
+.udelay_not_601:
+	mulli	r4,r3,1000	/* nanoseconds */
+	/*  Change r4 to be the number of ticks using:
+	 *	(nanoseconds + (timebase_period_ns - 1 )) / timebase_period_ns
+	 *  timebase_period_ns defaults to 60 (16.6MHz) */
+	mflr	r5
+	bl	0f
+0:	mflr	r6
+	mtlr	r5
+	lis	r5,0b@ha
+	addi	r5,r5,0b@l
+	subf	r5,r5,r6	/* In case we're relocated */
+	addis	r5,r5,timebase_period_ns@ha
+	lwz	r5,timebase_period_ns@l(r5)
+	add	r4,r4,r5
+	addi	r4,r4,-1
+	divw	r4,r4,r5	/* BUS ticks */
+1:	mftbu	r5
+	mftb	r6
+	mftbu	r7
+	cmpw	0,r5,r7
+	bne	1b		/* Get [synced] base time */
+	addc	r9,r6,r4	/* Compute end time */
+	addze	r8,r5
+2:	mftbu	r5
+	cmpw	0,r5,r8
+	blt	2b
+	bgt	3f
+	mftb	r6
+	cmpw	0,r6,r9
+	blt	2b
+3:	blr