u-boot/arch/arm/cpu/arm926ejs/mxs/start.S
Otavio Salvador 3a0398d7b9 mxs: reorganize source directory for easy sharing of code in i.MXS SoCs
Most code can be shared between i.MX23 and i.MX28 as both are from
i.MXS family; this source directory structure makes easy to share code
among them.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Acked-by: Stefano Babic <sbabic@denx.de>
2012-09-01 14:58:17 +02:00

247 lines
5.7 KiB
ArmAsm

/*
* armboot - Startup Code for ARM926EJS CPU-core
*
* Copyright (c) 2003 Texas Instruments
*
* ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------
*
* Copyright (c) 2001 Marius Groger <mag@sysgo.de>
* Copyright (c) 2002 Alex Zupke <azu@sysgo.de>
* Copyright (c) 2002 Gary Jennejohn <garyj@denx.de>
* Copyright (c) 2003 Richard Woodruff <r-woodruff2@ti.com>
* Copyright (c) 2003 Kshitij <kshitij@ti.com>
* Copyright (c) 2010 Albert Aribaud <albert.u.boot@aribaud.net>
*
* Change to support call back into iMX28 bootrom
* Copyright (c) 2011 Marek Vasut <marek.vasut@gmail.com>
* on behalf of DENX Software Engineering GmbH
*
* 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 <asm-offsets.h>
#include <config.h>
#include <common.h>
#include <version.h>
/*
*************************************************************************
*
* Jump vector table as in table 3.1 in [1]
*
*************************************************************************
*/
.globl _start
_start:
b reset
b undefined_instruction
b software_interrupt
b prefetch_abort
b data_abort
b not_used
b irq
b fiq
/*
* Vector table, located at address 0x20.
* This table allows the code running AFTER SPL, the U-Boot, to install it's
* interrupt handlers here. The problem is that the U-Boot is loaded into RAM,
* including it's interrupt vectoring table and the table at 0x0 is still the
* SPLs. So if interrupt happens in U-Boot, the SPLs interrupt vectoring table
* is still used.
*/
_vt_reset:
.word _reset
_vt_undefined_instruction:
.word _hang
_vt_software_interrupt:
.word _hang
_vt_prefetch_abort:
.word _hang
_vt_data_abort:
.word _hang
_vt_not_used:
.word _reset
_vt_irq:
.word _hang
_vt_fiq:
.word _hang
reset:
ldr pc, _vt_reset
undefined_instruction:
ldr pc, _vt_undefined_instruction
software_interrupt:
ldr pc, _vt_software_interrupt
prefetch_abort:
ldr pc, _vt_prefetch_abort
data_abort:
ldr pc, _vt_data_abort
not_used:
ldr pc, _vt_not_used
irq:
ldr pc, _vt_irq
fiq:
ldr pc, _vt_fiq
.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
*
*************************************************************************
*/
.globl _TEXT_BASE
_TEXT_BASE:
.word CONFIG_SYS_TEXT_BASE
/*
* These are defined in the board-specific linker script.
* Subtracting _start from them lets the linker put their
* relative position in the executable instead of leaving
* them null.
*/
.globl _bss_start_ofs
_bss_start_ofs:
.word __bss_start - _start
.globl _bss_end_ofs
_bss_end_ofs:
.word __bss_end__ - _start
.globl _end_ofs
_end_ofs:
.word _end - _start
#ifdef CONFIG_USE_IRQ
/* IRQ stack memory (calculated at run-time) */
.globl IRQ_STACK_START
IRQ_STACK_START:
.word 0x0badc0de
/* IRQ stack memory (calculated at run-time) */
.globl FIQ_STACK_START
FIQ_STACK_START:
.word 0x0badc0de
#endif
/* IRQ stack memory (calculated at run-time) + 8 bytes */
.globl IRQ_STACK_START_IN
IRQ_STACK_START_IN:
.word 0x0badc0de
/*
* the actual reset code
*/
_reset:
/*
* Store all registers on old stack pointer, this will allow us later to
* return to the BootROM and let the BootROM load U-Boot into RAM.
*/
push {r0-r12,r14}
/* save control register c1 */
mrc p15, 0, r0, c1, c0, 0
push {r0}
/*
* set the cpu to SVC32 mode and store old CPSR register content
*/
mrs r0,cpsr
push {r0}
bic r0,r0,#0x1f
orr r0,r0,#0xd3
msr cpsr,r0
/*
* we do sys-critical inits only at reboot,
* not when booting from ram!
*/
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
bl cpu_init_crit
#endif
bl board_init_ll
/*
* restore bootrom's cpu mode (especially FIQ)
*/
pop {r0}
msr cpsr,r0
/*
* restore c1 register
* (especially set exception vector location back to
* bootrom space which is required by bootrom for USB boot)
*/
pop {r0}
mcr p15, 0, r0, c1, c0, 0
pop {r0-r12,r14}
bx lr
/*
*************************************************************************
*
* CPU_init_critical registers
*
* setup important registers
* setup memory timing
*
*************************************************************************
*/
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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 */
orr r0, r0, #0x00001000 /* set bit 12 (I) I-Cache */
mcr p15, 0, r0, c1, c0, 0
mov pc, lr /* back to my caller */
.align 5
#endif /* CONFIG_SKIP_LOWLEVEL_INIT */
_hang:
ldr sp, _TEXT_BASE /* switch to abort stack */
1:
bl 1b /* hang and never return */