rockbox/firmware/target/arm/s5l8702/crt0.S

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id: crt0.S 18776 2008-10-11 18:32:17Z gevaerts $
 *
 * Copyright (C) 2008 by Marcoen Hirschberg
 * Copyright (C) 2008 by Denes Balatoni
 *
 * 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.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#define ASM
#include "config.h"
#include "cpu.h"

#define CACHE_NONE  0
#define CACHE_ALL   0x0C

    .section .intvect,"ax",%progbits
    .global    start
    .global    _newstart
    /* Exception vectors */
start:
    b _newstart
    ldr pc, =undef_instr_handler
    ldr pc, =software_int_handler
    ldr pc, =prefetch_abort_handler
    ldr pc, =data_abort_handler
    ldr pc, =reserved_handler
    ldr pc, =irq_handler
    ldr pc, =fiq_handler
    .ltorg
_newstart:
#if !defined(BOOTLOADER)
    ldr pc, =newstart2 // we do not want to execute from 0x0 as iram will be mapped there
    .section .init.text,"ax",%progbits
newstart2:
#endif
    msr     cpsr_c, #0xd3 /* enter supervisor mode, disable IRQ/FIQ */

#ifdef BOOTLOADER
    /* Relocate ourself to IRAM - we have been loaded to DRAM */
    mov    r0, #0x08000000   /* source (DRAM) */
    mov    r1, #0x22000000   /* dest (IRAM) */
    ldr    r2, =_dataend
1:
    cmp    r2, r1
    ldrhi  r3, [r0], #4
    strhi  r3, [r1], #4
    bhi    1b

    ldr    pc, =start_loc    /* jump to the relocated start_loc:  */
start_loc:
#endif

    mrc 15, 0, r0, c1, c0, 0
    bic r0, r0, #0x1000
    bic r0, r0, #0x5
    mcr 15, 0, r0, c1, c0, 0 // disable caches and protection unit

.cleancache:
    mrc	p15, 0, r15,c7,c10,3
    bne	.cleancache
    mov r0, #0
    mcr	p15, 0, r0,c7,c10,4
    mcr	p15, 0, r0,c7,c5,0
    bl      ttb_init

    mov     r0, #0                          @ physical address
    mov     r1, #0                          @ virtual address
    mov     r2, #0x380                      @ size (all memory)
    mov     r3, #CACHE_ALL
    bl      map_section

    mov     r0, #0x38000000                 @ physical address
    mov     r1, #0x38000000                 @ virtual address
    mov     r2, #0x80                       @ size (AHB/APB)
    mov     r3, #CACHE_NONE
    bl      map_section

    bl      enable_mmu

    mrc 15, 0, r0, c1, c0, 0
    orr r0, r0, #0x5
    orr r0, r0, #0x1000
    mcr 15, 0, r0, c1, c0, 0 // re-enable protection unit and caches

    ldr	r1, =0x38e00000
    add	r2, r1, #0x00001000
    add	r3, r1, #0x00002000
    sub	r4, r0, #1
    str	r4, [r1,#0x14]
    str	r4, [r2,#0x14]
    str	r4, [r1,#0xf00]
    str	r4, [r2,#0xf00]
    str	r4, [r3,#0x08]
    str	r4, [r3,#0x0c]
    str	r0, [r1,#0x14]
    str	r0, [r2,#0x14]
    
#if !defined(BOOTLOADER)
    /* Copy interrupt vectors to iram */
    ldr     r2, =_intvectstart
    ldr     r3, =_intvectend
    ldr     r4, =_intvectcopy
1:
    cmp     r3, r2
    ldrhi   r1, [r4], #4
    strhi   r1, [r2], #4
    bhi     1b
#endif

    /* Initialise bss section to zero */
    ldr     r2, =_edata
    ldr     r3, =_end
    mov     r4, #0
1:
    cmp     r3, r2
    strhi   r4, [r2], #4
    bhi     1b

#ifndef BOOTLOADER
    /* Copy icode and data to ram */
    ldr     r2, =_iramstart
    ldr     r3, =_iramend
    ldr     r4, =_iramcopy
1:
    cmp     r3, r2
    ldrhi   r1, [r4], #4
    strhi   r1, [r2], #4
    bhi     1b
    
    /* Initialise ibss section to zero */
    ldr     r2, =_iedata
    ldr     r3, =_iend
    mov     r4, #0
1:
    cmp     r3, r2
    strhi   r4, [r2], #4
    bhi     1b
#endif

    /* Set up some stack and munge it with 0xdeadbeef */
    ldr     sp, =stackend
    ldr     r2, =stackbegin
    ldr     r3, =0xdeadbeef
1:
    cmp     sp, r2
    strhi   r3, [r2], #4
    bhi     1b

    /* Set up stack for IRQ mode */ 
    msr     cpsr_c, #0xd2
    ldr     sp, =_irqstackend

    /* Set up stack for FIQ mode */ 
    msr     cpsr_c, #0xd1
    ldr     sp, =_fiqstackend

    /* Let abort and undefined modes use IRQ stack */
    msr     cpsr_c, #0xd7
    ldr     sp, =_irqstackend
    msr     cpsr_c, #0xdb
    ldr     sp, =_irqstackend

    /* Switch back to supervisor mode */
    msr     cpsr_c, #0xd3

    bl      main

    .text
/*    .global UIE*/

/* All illegal exceptions call into UIE with exception address as first
 * parameter. This is calculated differently depending on which exception
 * we're in. Second parameter is exception number, used for a string lookup
 * in UIE. */
undef_instr_handler:
    sub    r0, lr, #4
    mov    r1, #0
    b      UIE

/* We run supervisor mode most of the time, and should never see a software
 * exception being thrown. Perhaps make it illegal and call UIE? */
software_int_handler:
reserved_handler:
    movs   pc, lr

prefetch_abort_handler:
    sub    r0, lr, #4
    mov    r1, #1
    b      UIE

data_abort_handler:
    sub    r0, lr, #8 
    mov    r1, #2
    b      UIE