www.pudn.com > x-load.rar > start.S
/*
* armboot - Startup Code for OMP2420/ARM1136 CPU-core
*
* Copyright (c) 2004 Texas Instruments
*
* Copyright (c) 2001 Marius Gröger
* Copyright (c) 2002 Alex Züpke
* Copyright (c) 2002 Gary Jennejohn
* Copyright (c) 2003 Richard Woodruff
* Copyright (c) 2003 Kshitij
* Copyright (c) 2004 Jian Zhang
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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 program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include
.globl _start
_start:
b reset
ldr pc, _hang
ldr pc, _hang
ldr pc, _hang
ldr pc, _hang
ldr pc, _hang
ldr pc, _hang
ldr pc, _hang
_hang:
.word do_hang
.word 0x12345678
.word 0x12345678
.word 0x12345678
.word 0x12345678
.word 0x12345678
.word 0x12345678
.word 0x12345678 /* now 16*4=64 */
.global _end_vect
_end_vect:
.balignl 16,0xdeadbeef
/*
*************************************************************************
*
* Startup Code (reset vector)
*
* do important init only if we don't start from memory!
* setup Memory and board specific bits prior to relocation.
* relocate armboot to ram
* setup stack
*
*************************************************************************
*/
_TEXT_BASE:
.word TEXT_BASE
.globl _armboot_start
_armboot_start:
.word _start
/*
* These are defined in the board-specific linker script.
*/
.globl _bss_start
_bss_start:
.word __bss_start
.globl _bss_end
_bss_end:
.word _end
/*
* the actual reset code
*/
reset:
/*
* set the cpu to SVC32 mode
*/
mrs r0,cpsr
bic r0,r0,#0x1f
orr r0,r0,#0xd3
msr cpsr,r0
/* Copy vectors to mask ROM indirect addr */
adr r0, _start /* r0 <- current position of code */
add r0, r0, #4 /* skip reset vector */
mov r2, #64 /* r2 <- size to copy */
add r2, r0, r2 /* r2 <- source end address */
mov r1, #0x40000000 /* build vect addr */
mov r3, #0x00200000
add r1, r1, r3
mov r3, #0xf800
add r1, r1, r3
next:
ldmia r0!, {r3-r10} /* copy from source address [r0] */
stmia r1!, {r3-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end address [r2] */
bne next /* loop until equal */
bl cpy_clk_code /* put dpll adjust code behind vectors */
/* the mask ROM code should have PLL and others stable */
bl cpu_init_crit
relocate: /* relocate U-Boot to RAM */
adr r0, _start /* r0 <- current position of code */
ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
cmp r0, r1 /* don't reloc during debug */
/* beq stack_setup */
ldr r2, _armboot_start
ldr r3, _bss_start
sub r2, r3, r2 /* r2 <- size of armboot */
add r2, r0, r2 /* r2 <- source end address */
copy_loop:
ldmia r0!, {r3-r10} /* copy from source address [r0] */
stmia r1!, {r3-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end addreee [r2] */
ble copy_loop
/* Set up the stack */
stack_setup:
ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */
sub sp, r0, #128 /* leave 32 words for abort-stack */
clear_bss:
ldr r0, _bss_start /* find start of bss segment */
ldr r1, _bss_end /* stop here */
mov r2, #0x00000000 /* clear */
//clbss_l:str r2, [r0] /* clear loop... */
// add r0, r0, #4
// cmp r0, r1
// bne clbss_l
ldr pc, _start_armboot
_start_armboot: .word start_armboot
/*
*************************************************************************
*
* CPU_init_critical registers
*
* setup important registers
* setup memory timing
*
*************************************************************************
*/
cpu_init_crit:
/*
* flush v4 I/D caches
*/
mov r0, #0
mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
/*
* disable MMU stuff and caches
*/
mrc p15, 0, r0, c1, c0, 0
bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
orr r0, r0, #0x00000002 @ set bit 2 (A) Align
#ifndef CONFIG_ICACHE_OFF
orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
#endif
mcr p15, 0, r0, c1, c0, 0
/*
* Jump to board specific initialization... The Mask ROM will have already initialized
* basic memory. Go here to bump up clock rate and handle wake up conditions.
*/
adr r0, _start /* r0 <- current position of code */
ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
cmp r0, r1 /* pass on info about skipping some init portions */
moveq r0,#0x1 /* flag to skip prcm and sdrc setup */
movne r0,#0x0
//mov r0, #1 /* this skip memory init */
mov ip, lr /* persevere link reg across call */
bl platformsetup /* go setup pll,mux,memory */
mov lr, ip /* restore link */
mov pc, lr /* back to my caller */
/*
* exception handler
*/
.align 5
do_hang:
ldr sp, _TEXT_BASE /* use 32 words abort stack */
bl hang /* hang and never return */