xref: /kernel/linux/linux-6.6/arch/powerpc/boot/wii-head.S

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * arch/powerpc/boot/wii-head.S
 *
 * Nintendo Wii bootwrapper entry.
 * Copyright (C) 2008-2009 The GameCube Linux Team
 * Copyright (C) 2008,2009 Albert Herranz
 */

#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