/* 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