gamecube-head.S
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/*
* arch/powerpc/boot/gamecube-head.S
*
* Nintendo GameCube bootwrapper entry.
* Copyright (C) 2004-2009 The GameCube Linux Team
* Copyright (C) 2008,2009 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"
/*
* The entry code does no assumptions regarding:
* - if the data and instruction caches are enabled or not
* - if the MMU is enabled or not
*
* We enable the caches if not already enabled, enable the MMU with an
* identity mapping scheme and jump to the start code.
*/
.text
.globl _zimage_start
_zimage_start:
/* turn the MMU off */
mfmsr 9
rlwinm 9, 9, 0, ~((1<<4)|(1<<5)) /* MSR_DR|MSR_IR */
bcl 20, 31, 1f
1:
mflr 8
clrlwi 8, 8, 3 /* convert to a real address */
addi 8, 8, _mmu_off - 1b
mtsrr0 8
mtsrr1 9
rfi
_mmu_off:
/* MMU disabled */
/* setup BATs */
isync
li 8, 0
mtspr 0x210, 8 /* IBAT0U */
mtspr 0x212, 8 /* IBAT1U */
mtspr 0x214, 8 /* IBAT2U */
mtspr 0x216, 8 /* IBAT3U */
mtspr 0x218, 8 /* DBAT0U */
mtspr 0x21a, 8 /* DBAT1U */
mtspr 0x21c, 8 /* DBAT2U */
mtspr 0x21e, 8 /* DBAT3U */
li 8, 0x01ff /* first 16MiB */
li 9, 0x0002 /* rw */
mtspr 0x211, 9 /* IBAT0L */
mtspr 0x210, 8 /* IBAT0U */
mtspr 0x219, 9 /* DBAT0L */
mtspr 0x218, 8 /* DBAT0U */
lis 8, 0x0c00 /* I/O mem */
ori 8, 8, 0x3ff /* 32MiB */
lis 9, 0x0c00
ori 9, 9, 0x002a /* uncached, guarded, rw */
mtspr 0x21b, 9 /* DBAT1L */
mtspr 0x21a, 8 /* DBAT1U */
lis 8, 0x0100 /* next 8MiB */
ori 8, 8, 0x00ff /* 8MiB */
lis 9, 0x0100
ori 9, 9, 0x0002 /* rw */
mtspr 0x215, 9 /* IBAT2L */
mtspr 0x214, 8 /* IBAT2U */
mtspr 0x21d, 9 /* DBAT2L */
mtspr 0x21c, 8 /* DBAT2U */
/* enable and invalidate the caches if not already enabled */
mfspr 8, 0x3f0 /* HID0 */
andi. 0, 8, (1<<15) /* HID0_ICE */
bne 1f
ori 8, 8, (1<<15)|(1<<11) /* HID0_ICE|HID0_ICFI*/
1:
andi. 0, 8, (1<<14) /* HID0_DCE */
bne 1f
ori 8, 8, (1<<14)|(1<<10) /* HID0_DCE|HID0_DCFI*/
1:
mtspr 0x3f0, 8 /* HID0 */
isync
/* initialize arguments */
li 3, 0
li 4, 0
li 5, 0
/* turn the MMU on */
bcl 20, 31, 1f
1:
mflr 8
addi 8, 8, _mmu_on - 1b
mfmsr 9
ori 9, 9, (1<<4)|(1<<5) /* MSR_DR|MSR_IR */
mtsrr0 8
mtsrr1 9
sync
rfi
_mmu_on:
b _zimage_start_lib