This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / arch / powerpc / boot / util.S

diff --git a/arch/powerpc/boot/util.S b/arch/powerpc/boot/util.S
new file mode 100644 (file)
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+++ b/arch/powerpc/boot/util.S
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+/*
+ * 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