NetBSD/sys/arch/mipsco/stand/common/prom.S
wdk 7495cd76b1 Since we don't have a lseek function in the PROM firmware standalone libs
we have to poke the data structures directly to force the offset we need.

The open() function returns with the address of the IO control block in
register t0 so we take a copy of it for our brute-force lseek function.

This should be reasonably portable since the firmware writers closely
follow UNIX semantics and the open stubs should recompile and use the
same registers.   May break on the rebadged clones -- buyer beware.

The alternative is to use dummy reads to go forwards and reopen followed
by dummy reads to go backwards.  It takes around 60 seconds to boot
using this method if we use a clean filesystem.

Tested with firmware versions 5.40 and 5.43
2000-09-26 09:32:25 +00:00

118 lines
3.0 KiB
ArmAsm

/* $NetBSD: prom.S,v 1.2 2000/09/26 09:32:25 wdk Exp $ */
/*
* Copyright (c) 2000 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Wayne Knowles
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <mips/asm.h>
#include <mips/cpuregs.h>
#include <machine/prom.h>
LEAF(prom_restart)
li v0, MIPS_PROM_RESTART
j v0
move a0, zero
END(prom_restart)
NESTED(prom_open, CALLFRAME_SIZ, ra)
.mask 0x80000000, -4
subu sp, sp, CALLFRAME_SIZ
sw ra, CALLFRAME_RA(sp)
li v0, MIPS_PROM_OPEN
jal v0
nop
/*
* On return t0 contains our _iob structure
* v0 contains the file descriptor number
*/
la t4, saiob
sll t5, v0, 2
add t4, t4, t5
lw ra, CALLFRAME_RA(sp)
addu sp, sp, CALLFRAME_SIZ
sw t0, 0(t4)
j ra
nop
END(prom_open)
#ifndef LIBSA_NO_DEV_CLOSE
LEAF(prom_close)
li v0, MIPS_PROM_CLOSE
j v0
nop
END(prom_close)
#endif
LEAF(prom_read)
li v0, MIPS_PROM_READ
j v0
nop
END(prom_read)
#ifndef LIBSA_NO_FS_WRITE
LEAF(prom_write)
li v0, MIPS_PROM_WRITE
j v0
nop
END(prom_write)
#endif
LEAF(printf)
li v0, MIPS_PROM_PRINTF
j v0
nop
END(printf)
#ifndef NO_GETCHAR
LEAF(getchar)
li v0, MIPS_PROM_GETCHAR
j v0
nop
END(getchar)
LEAF(putchar)
li v0, MIPS_PROM_PUTCHAR
j v0
nop
END(putchar)
#endif
.sdata
.global saiob
saiob: .space 8*4