u-boot/cpu/at32ap/start.S
Haavard Skinnemoen 1f4f2121c2 AVR32: Relocate u-boot to SDRAM
Relocate the u-boot image into SDRAM like everyone else does. This
means that we can handle much larger .data and .bss than we used to.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2007-04-14 15:20:27 +02:00

165 lines
3.5 KiB
ArmAsm

/*
* Copyright (C) 2005-2006 Atmel Corporation
*
* 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 <config.h>
#include <asm/sysreg.h>
#ifndef PART_SPECIFIC_BOOTSTRAP
# define PART_SPECIFIC_BOOTSTRAP
#endif
#define SYSREG_MMUCR_I_OFFSET 2
#define SYSREG_MMUCR_S_OFFSET 4
#define SR_INIT (SYSREG_BIT(GM) | SYSREG_BIT(EM) | SYSREG_BIT(M0))
#define CPUCR_INIT (SYSREG_BIT(BI) | SYSREG_BIT(BE) \
| SYSREG_BIT(FE) | SYSREG_BIT(RE) \
| SYSREG_BIT(IBE) | SYSREG_BIT(IEE))
.text
.global _start
_start:
PART_SPECIFIC_BOOTSTRAP
/* Reset the Status Register */
mov r0, lo(SR_INIT)
orh r0, hi(SR_INIT)
mtsr SYSREG_SR, r0
/* Reset CPUCR and invalidate the BTB */
mov r2, CPUCR_INIT
mtsr SYSREG_CPUCR, r2
/* Flush the caches */
mov r1, 0
cache r1[4], 8
cache r1[0], 0
sync 0
/* Reset the MMU to default settings */
mov r0, SYSREG_BIT(MMUCR_S) | SYSREG_BIT(MMUCR_I)
mtsr SYSREG_MMUCR, r0
/* Internal RAM should not need any initialization. We might
have to initialize external RAM here if the part doesn't
have internal RAM (or we may use the data cache) */
/* Jump to cacheable segment */
lddpc pc, 1f
.align 2
1: .long 2f
2: lddpc sp, sp_init
/* Initialize the GOT pointer */
lddpc r6, got_init
3: rsub r6, pc
/* Let's go */
rjmp board_init_f
.align 2
.type sp_init,@object
sp_init:
.long CFG_INIT_SP_ADDR
got_init:
.long 3b - _GLOBAL_OFFSET_TABLE_
/*
* void relocate_code(new_sp, new_gd, monitor_addr)
*
* Relocate the u-boot image into RAM and continue from there.
* Does not return.
*/
.global relocate_code
.type relocate_code,@function
relocate_code:
mov sp, r12 /* use new stack */
mov r12, r11 /* save new_gd */
mov r11, r10 /* save destination address */
/* copy .text section and flush the cache along the way */
lda.w r8, _text
lda.w r9, _etext
sub lr, r10, r8 /* relocation offset */
1: ldm r8++, r0-r3
stm r10, r0-r3
sub r10, -16
ldm r8++, r0-r3
stm r10, r0-r3
sub r10, -16
cp.w r8, r9
cache r10[-4], 0x0d /* dcache clean/invalidate */
cache r10[-4], 0x01 /* icache invalidate */
brlt 1b
/* flush write buffer */
sync 0
/* copy data sections */
lda.w r9, _edata
1: ld.d r0, r8++
st.d r10++, r0
cp.w r8, r9
brlt 1b
/* zero out .bss */
mov r0, 0
mov r1, 0
lda.w r9, _end
sub r9, r8
1: st.d r10++, r0
sub r9, 8
brgt 1b
/* jump to RAM */
sub r0, pc, . - in_ram
add pc, r0, lr
.align 2
in_ram:
/* find the new GOT and relocate it */
lddpc r6, got_init_reloc
3: rsub r6, pc
mov r8, r6
lda.w r9, _egot
lda.w r10, _got
sub r9, r10
1: ld.w r0, r8[0]
add r0, lr
st.w r8++, r0
sub r9, 4
brgt 1b
/* Move the exception handlers */
mfsr r2, SYSREG_EVBA
add r2, lr
mtsr SYSREG_EVBA, r2
/* Do the rest of the initialization sequence */
call board_init_r
.align 2
got_init_reloc:
.long 3b - _GLOBAL_OFFSET_TABLE_