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Albert Herranzb68a24b2009-12-12 06:31:36 +00001/*
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