mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 05:34:00 +08:00
b1576fec7f
binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
103 lines
2.3 KiB
ArmAsm
103 lines
2.3 KiB
ArmAsm
/*
|
|
* 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 .Ludelay_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
|
|
|
|
.Ludelay_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 */
|
|
#ifdef CONFIG_8xx
|
|
1: mftbu r5
|
|
mftb r6
|
|
mftbu r7
|
|
#else
|
|
1: mfspr r5, SPRN_TBRU
|
|
mfspr r6, SPRN_TBRL
|
|
mfspr r7, SPRN_TBRU
|
|
#endif
|
|
cmpw 0,r5,r7
|
|
bne 1b /* Get [synced] base time */
|
|
addc r9,r6,r4 /* Compute end time */
|
|
addze r8,r5
|
|
#ifdef CONFIG_8xx
|
|
2: mftbu r5
|
|
#else
|
|
2: mfspr r5, SPRN_TBRU
|
|
#endif
|
|
cmpw 0,r5,r8
|
|
blt 2b
|
|
bgt 3f
|
|
#ifdef CONFIG_8xx
|
|
mftb r6
|
|
#else
|
|
mfspr r6, SPRN_TBRL
|
|
#endif
|
|
cmpw 0,r6,r9
|
|
blt 2b
|
|
3: blr
|