1/* 2 * arch/powerpc/boot/gamecube-head.S 3 * 4 * Nintendo GameCube bootwrapper entry. 5 * Copyright (C) 2004-2009 The GameCube Linux Team 6 * Copyright (C) 2008,2009 Albert Herranz 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License 10 * as published by the Free Software Foundation; either version 2 11 * of the License, or (at your option) any later version. 12 * 13 */ 14 15#include "ppc_asm.h" 16 17/* 18 * The entry code does no assumptions regarding: 19 * - if the data and instruction caches are enabled or not 20 * - if the MMU is enabled or not 21 * 22 * We enable the caches if not already enabled, enable the MMU with an 23 * identity mapping scheme and jump to the start code. 24 */ 25 26 .text 27 28 .globl _zimage_start 29_zimage_start: 30 31 /* turn the MMU off */ 32 mfmsr 9 33 rlwinm 9, 9, 0, ~((1<<4)|(1<<5)) /* MSR_DR|MSR_IR */ 34 bcl 20, 31, 1f 351: 36 mflr 8 37 clrlwi 8, 8, 3 /* convert to a real address */ 38 addi 8, 8, _mmu_off - 1b 39 mtsrr0 8 40 mtsrr1 9 41 rfi 42_mmu_off: 43 /* MMU disabled */ 44 45 /* setup BATs */ 46 isync 47 li 8, 0 48 mtspr 0x210, 8 /* IBAT0U */ 49 mtspr 0x212, 8 /* IBAT1U */ 50 mtspr 0x214, 8 /* IBAT2U */ 51 mtspr 0x216, 8 /* IBAT3U */ 52 mtspr 0x218, 8 /* DBAT0U */ 53 mtspr 0x21a, 8 /* DBAT1U */ 54 mtspr 0x21c, 8 /* DBAT2U */ 55 mtspr 0x21e, 8 /* DBAT3U */ 56 57 li 8, 0x01ff /* first 16MiB */ 58 li 9, 0x0002 /* rw */ 59 mtspr 0x211, 9 /* IBAT0L */ 60 mtspr 0x210, 8 /* IBAT0U */ 61 mtspr 0x219, 9 /* DBAT0L */ 62 mtspr 0x218, 8 /* DBAT0U */ 63 64 lis 8, 0x0c00 /* I/O mem */ 65 ori 8, 8, 0x3ff /* 32MiB */ 66 lis 9, 0x0c00 67 ori 9, 9, 0x002a /* uncached, guarded, rw */ 68 mtspr 0x21b, 9 /* DBAT1L */ 69 mtspr 0x21a, 8 /* DBAT1U */ 70 71 lis 8, 0x0100 /* next 8MiB */ 72 ori 8, 8, 0x00ff /* 8MiB */ 73 lis 9, 0x0100 74 ori 9, 9, 0x0002 /* rw */ 75 mtspr 0x215, 9 /* IBAT2L */ 76 mtspr 0x214, 8 /* IBAT2U */ 77 mtspr 0x21d, 9 /* DBAT2L */ 78 mtspr 0x21c, 8 /* DBAT2U */ 79 80 /* enable and invalidate the caches if not already enabled */ 81 mfspr 8, 0x3f0 /* HID0 */ 82 andi. 0, 8, (1<<15) /* HID0_ICE */ 83 bne 1f 84 ori 8, 8, (1<<15)|(1<<11) /* HID0_ICE|HID0_ICFI*/ 851: 86 andi. 0, 8, (1<<14) /* HID0_DCE */ 87 bne 1f 88 ori 8, 8, (1<<14)|(1<<10) /* HID0_DCE|HID0_DCFI*/ 891: 90 mtspr 0x3f0, 8 /* HID0 */ 91 isync 92 93 /* initialize arguments */ 94 li 3, 0 95 li 4, 0 96 li 5, 0 97 98 /* turn the MMU on */ 99 bcl 20, 31, 1f 1001: 101 mflr 8 102 addi 8, 8, _mmu_on - 1b 103 mfmsr 9 104 ori 9, 9, (1<<4)|(1<<5) /* MSR_DR|MSR_IR */ 105 mtsrr0 8 106 mtsrr1 9 107 sync 108 rfi 109_mmu_on: 110 b _zimage_start_lib 111