/*      $NetBSD: kloader_pxa2x0.S,v 1.2 2021/10/11 14:29:15 rin Exp $   */

/*-
 * Copyright (C) 2012 NONAKA Kimihiro <nonaka@netbsd.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <machine/asm.h>

#include <arm/armreg.h>

#define VATOPA(reg)                                                     \
        bic     reg, reg, #0xff000000   /* clear upper 8 bits */        ;\
        orr     reg, reg, #0xa0000000   /* OR in physical base address */

        .text
        .align  0
/*
 * void
 * kloader_pxa2x0_boot(struct kloader_bootinfo *kbi,
 *                     struct kloader_page_tag *tag)
 *
 * r0: kbi, r1: tag
 */
        .global _C_LABEL(kloader_pxa2x0_boot)
_C_LABEL(kloader_pxa2x0_boot):
        mov     lr, r0                  /* lr: kbi */
        VATOPA(lr)

        /* We will go ahead and disable the MMU here. */
        adr     r8, .Lmmuoff
        VATOPA(r8)

        mrc     p15, 0, r2, c1, c0, 0
        bic     r2, r2, #CPU_CONTROL_MMU_ENABLE
        bic     r2, r2, #CPU_CONTROL_DC_ENABLE
        bic     r2, r2, #CPU_CONTROL_IC_ENABLE
        mcr     p15, 0, r2, c1, c0, 0

        nop
        nop
        nop

        mov     pc, r8                  /* Heave-ho! */

        .align  0
.Lmmuoff:
        nop
        nop
        nop

        /* Load kernel image */
        mov     r4, r1          /* tag */
1:      mov     r3, r4
        cmp     r3, #0          /* tag == NULL */
        beq     3f
        VATOPA(r3)
        ldmia   r3, {r4-r7}     /* r4: next, r5: src, r6: dst, r7: sz */
        VATOPA(r5)
        VATOPA(r6)
        add     r8, r6, r7      /* r8: dst + sz */
2:      ldr     r9, [r5], #4    /* copy */
        str     r9, [r6], #4
        cmp     r8, r6
        bne     2b
        b       1b

3:
        /* Set temporary stack pointer */
        ldr     sp, .Lstack_addr

        /* Jump to kernel entry */
        mov     r3, lr                  /* r3: kbi */
        ldr     lr, [r3]                /* kbi->entry */
        VATOPA(lr)
        ldr     r0, [r3, #4]            /* kbi->argc */
        ldr     r1, [r3, #8]            /* kbi->argv */
        add     r2, r3, #12             /* &kbi->bootinfo */

        /* Fixup argv[] */
        cmp     r1, #0                  /* argv == NULL */
        beq     5f
        VATOPA(r1)
        cmp     r0, #0                  /* argc == 0 */
        beq     5f

        mov     r3, r0
        mov     r4, r1
4:      ldr     r5, [r4]
        VATOPA(r5)
        str     r5, [r4], #4
        subs    r3, r3, #1
        bgt     4b

5:      /* Jump! */
        mov     pc, lr

99:     b       99b

.Lstack_addr:
        .word   0xa0004000