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 000000000000..427ddfc11991
--- /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