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/*
* Copyright (c) 2004 Cucy Systems (http://www.cucy.com)
* Curt Brune <curt@cucy.com>
*
* 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 <version.h>
#include <asm/hardware.h>
/***********************************************************************
* Configure Memory Map
*
* This memory map allows us to relocate from FLASH to SRAM. After
* power-on reset the CPU only knows about the FLASH memory at address
* 0x00000000. After lowlevel_init completes the memory map will be:
*
* Memory Addr
* 0x00000000
* to 8MB SRAM (U5) -- 8MB Map
* 0x00800000
*
* 0x01000000
* to 2MB Flash @ 0x00000000 (U7) -- 2MB Map
* 0x01200000
*
* 0x02000000
* to 512KB Flash @ 0x02000000 (U9) -- 2MB Map
* 0x02080000
*
* Load all 12 memory registers with the STMIA instruction since
* memory access is disabled once these registers are written. The
* last register written re-enables memory access. For more info see
* the user's manual for the S3C4510B, available from Samsung's web
* site. Search for part number "S3C4510B".
*
***********************************************************************/
.globl lowlevel_init
lowlevel_init:
/* preserve the temp register (r12 AKA ip) and remap it. */
ldr r1, =SRAM_BASE+0xC
add r0, r12, #0x01000000
str r0, [r1]
/* remap the link register for when we return */
add lr, lr, #0x01000000
/* store a short program in the on chip SRAM, which is
* unaffected when remapping memory. Note the cache must be
* disabled for the on chip SRAM to be available.
*/
ldr r1, =SRAM_BASE
ldr r0, =0xe8801ffe /* stmia r0, {r1-r12} */
str r0, [r1]
add r1, r1, #4
ldr r0, =0xe59fc000 /* ldr r12, [pc, #0] */
str r0, [r1]
add r1, r1, #4
ldr r0, =0xe1a0f00e /* mov pc, lr */
str r0, [r1]
adr r0, memory_map_data
ldmia r0, {r1-r12}
ldr r0, =REG_EXTDBWTH
ldr pc, =SRAM_BASE
.globl reset_cpu
reset_cpu:
/*
* reset the cpu by re-mapping FLASH 0 to 0x0 and jumping to
* address 0x0. We accomplish this by storing a few
* instructions into the on chip SRAM (8KB) and run from
* there. Note the cache must be disabled for the on chip
* SRAM to be available.
*
* load r2 with REG_ROMCON0
* load r3 with 0x12040060 configure FLASH bank 0 @ 0x00000000
* load r4 with REG_DRAMCON0
* load r5 with 0x08000380 configure RAM bank 0 @ 0x01000000
* load r6 with REG_REFEXTCON
* load r7 with 0x9c218360
* load r8 with 0x0
* store str r3,[r2] @ SRAM_BASE
* store str r5,[r4] @ SRAM_BASE + 0x4
* store str r7,[r6] @ SRAM_BASE + 0x8
* store mov pc,r8 @ SRAM_BASE + 0xC
* mov pc, SRAM_BASE
*
*/
/* disable cache */
ldr r0, =REG_SYSCFG
ldr r1, =0x83ffffa0 /* cache-disabled */
str r1, [r0]
ldr r2, =REG_ROMCON0
ldr r3, =0x02000060 /* Bank0 2MB FLASH @ 0x00000000 */
ldr r4, =REG_DRAMCON0
ldr r5, =0x18040380 /* DRAM0 8MB SRAM @ 0x01000000 */
ldr r6, =REG_REFEXTCON
ldr r7, =0xce278360
ldr r8, =0x00000000
ldr r1, =SRAM_BASE
ldr r0, =0xe5823000 /* str r3, [r2] */
str r0, [r1]
ldr r1, =SRAM_BASE+4
ldr r0, =0xe5845000 /* str r5, [r4] */
str r0, [r1]
ldr r1, =SRAM_BASE+8
ldr r0, =0xe5867000 /* str r7, [r6] */
str r0, [r1]
ldr r1, =SRAM_BASE+0xC
ldr r0, =0xe1a0f008 /* mov pc, r8 */
str r0, [r1]
ldr r1, =SRAM_BASE
mov pc, r1
/* never return */
/************************************************************************
* Below are twelve 32-bit values for the twelve memory registers of
* the system manager, starting with register REG_EXTDBWTH.
***********************************************************************/
memory_map_data:
.long 0x00f03005 /* memory widths */
.long 0x12040060 /* Bank0 2MB FLASH @ 0x01000000 */
.long 0x22080060 /* Bank1 512KB FLASH @ 0x02000000 */
.long 0x00000000
.long 0x00000000
.long 0x00000000
.long 0x00000000
.long 0x08000380 /* DRAM0 8MB SRAM @ 0x00000000 */
.long 0x00000000
.long 0x00000000
.long 0x00000000
.long 0x9c218360 /* enable memory */
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