/*
   * arch/powerpc/boot/wii-head.S
   *
   * Nintendo Wii bootwrapper entry.
   * Copyright (C) 2008-2009 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
   * - if the high BATs are enabled or not
   *
   * We enable the high BATs, 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 */
  
  	mtspr	0x230, 8	/* IBAT4U */
  	mtspr	0x232, 8	/* IBAT5U */
  	mtspr	0x234, 8	/* IBAT6U */
  	mtspr	0x236, 8	/* IBAT7U */
  	mtspr	0x238, 8	/* DBAT4U */
  	mtspr	0x23a, 8	/* DBAT5U */
  	mtspr	0x23c, 8	/* DBAT6U */
  	mtspr	0x23e, 8	/* DBAT7U */
  
  	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 */
  
  	lis	8, 0x1000	/* MEM2 */
  	ori	8, 8, 0x07ff	/* 64MiB */
  	lis	9, 0x1000
  	ori	9, 9, 0x0002	/* rw */
  	mtspr	0x216, 8	/* IBAT3U */
  	mtspr	0x217, 9	/* IBAT3L */
  	mtspr	0x21e, 8	/* DBAT3U */
  	mtspr	0x21f, 9	/* DBAT3L */
  
  	/* enable the high BATs */
  	mfspr	8, 0x3f3	/* HID4 */
  	oris	8, 8, 0x0200
  	mtspr	0x3f3, 8	/* HID4 */
  
  	/* 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:
  	/* turn on the front blue led (aka: yay! we got here!) */
  	lis	8, 0x0d00
  	ori	8, 8, 0x00c0
  	lwz	9, 0(8)
  	ori	9, 9, 0x20
  	stw	9, 0(8)
  
  	b _zimage_start_lib