kernel-ark/arch/powerpc/platforms/44x/misc_44x.S
David Gibson d9b55a0361 [POWERPC] Early serial debug support for PPC44x
This adds support for early serial debugging via the built in
port on IBM/AMCC PowerPC 44x CPUs.  It uses a bolted TLB entry in
address space 1 for the UART's mapping, allowing robust debugging both
before and after the initialization of the MMU.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-05-08 14:47:33 +10:00

58 lines
1005 B
ArmAsm

/*
* This file contains miscellaneous low-level functions for PPC 44x.
* Copyright 2007 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
*
* 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 <asm/reg.h>
#include <asm/ppc_asm.h>
.text
/*
* Do an IO access in AS1
*/
_GLOBAL(as1_readb)
mfmsr r7
ori r0,r7,MSR_DS
sync
mtmsr r0
sync
isync
lbz r3,0(r3)
sync
mtmsr r7
sync
isync
blr
_GLOBAL(as1_writeb)
mfmsr r7
ori r0,r7,MSR_DS
sync
mtmsr r0
sync
isync
stb r3,0(r4)
sync
mtmsr r7
sync
isync
blr
/*
* void ppc44x_reset_system(char *cmd)
*
* At present, this routine just applies a system reset.
*/
_GLOBAL(ppc44x_reset_system)
mfspr r13,SPRN_DBCR0
oris r13,r13,DBCR0_RST_SYSTEM@h
mtspr SPRN_DBCR0,r13
b . /* Just in case the reset doesn't work */