diff options
Diffstat (limited to 'arch/arm/cpu/s3c44b0/start.S')
| -rw-r--r-- | arch/arm/cpu/s3c44b0/start.S | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/arch/arm/cpu/s3c44b0/start.S b/arch/arm/cpu/s3c44b0/start.S new file mode 100644 index 0000000..f5a3d3a --- /dev/null +++ b/arch/arm/cpu/s3c44b0/start.S @@ -0,0 +1,272 @@ +/* + * Startup Code for S3C44B0 CPU-core + * + * (C) Copyright 2004 + * DAVE Srl + * + * http://www.dave-tech.it + * http://www.wawnet.biz + * mailto:info@wawnet.biz + * + * 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> + + +/* + * Jump vector table + */ + + +.globl _start +_start: b reset + add pc, pc, #0x0c000000 + add pc, pc, #0x0c000000 + add pc, pc, #0x0c000000 + add pc, pc, #0x0c000000 + add pc, pc, #0x0c000000 + add pc, pc, #0x0c000000 + add pc, pc, #0x0c000000 + + .balignl 16,0xdeadbeef + + +/* + ************************************************************************* + * + * Startup Code (reset vector) + * + * do important init only if we don't start from memory! + * relocate u-boot to ram + * setup stack + * jump to second stage + * + ************************************************************************* + */ + +_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 + +#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 + + +/* + * the actual reset code + */ + +reset: + /* + * set the cpu to SVC32 mode + */ + mrs r0,cpsr + bic r0,r0,#0x1f + orr r0,r0,#0x13 + 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 + /* + * before relocating, we have to setup RAM timing + * because memory timing is board-dependend, you will + * find a lowlevel_init.S in your board directory. + */ + bl lowlevel_init +#endif + +#ifndef CONFIG_SKIP_RELOCATE_UBOOT +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 + +/* + now copy to sram the interrupt vector +*/ + adr r0, real_vectors + add r2, r0, #1024 + ldr r1, =0x0c000000 + add r1, r1, #0x08 +vector_copy_loop: + ldmia r0!, {r3-r10} + stmia r1!, {r3-r10} + cmp r0, r2 + ble vector_copy_loop +#endif /* CONFIG_SKIP_RELOCATE_UBOOT */ + + /* Set up the stack */ +stack_setup: + ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */ + sub r0, r0, #CONFIG_SYS_MALLOC_LEN /* malloc area */ + sub r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo */ +#ifdef CONFIG_USE_IRQ + sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ) +#endif + sub sp, r0, #12 /* leave 3 words for abort-stack */ + + ldr pc, _start_armboot + +_start_armboot: .word start_armboot + + +/* + ************************************************************************* + * + * CPU_init_critical registers + * + * setup important registers + * setup memory timing + * + ************************************************************************* + */ + +#define INTCON (0x01c00000+0x200000) +#define INTMSK (0x01c00000+0x20000c) +#define LOCKTIME (0x01c00000+0x18000c) +#define PLLCON (0x01c00000+0x180000) +#define CLKCON (0x01c00000+0x180004) +#define WTCON (0x01c00000+0x130000) +cpu_init_crit: + /* disable watch dog */ + ldr r0, =WTCON + ldr r1, =0x0 + str r1, [r0] + + /* + * mask all IRQs by clearing all bits in the INTMRs + */ + ldr r1,=INTMSK + ldr r0, =0x03fffeff + str r0, [r1] + + ldr r1, =INTCON + ldr r0, =0x05 + str r0, [r1] + + /* Set Clock Control Register */ + ldr r1, =LOCKTIME + ldrb r0, =800 + strb r0, [r1] + + ldr r1, =PLLCON + +#if CONFIG_S3C44B0_CLOCK_SPEED==66 + ldr r0, =0x34031 /* 66MHz (Quartz=11MHz) */ +#elif CONFIG_S3C44B0_CLOCK_SPEED==75 + ldr r0, =0x610c1 /*B2: Xtal=20mhz Fclk=75MHz */ +#else +# error CONFIG_S3C44B0_CLOCK_SPEED undefined +#endif + + str r0, [r1] + + ldr r1,=CLKCON + ldr r0, =0x7ff8 + str r0, [r1] + + mov pc, lr + + +/*************************************************/ +/* interrupt vectors */ +/*************************************************/ +real_vectors: + b reset + b undefined_instruction + b software_interrupt + b prefetch_abort + b data_abort + b not_used + b irq + b fiq + +/*************************************************/ + +undefined_instruction: + mov r6, #3 + b reset + +software_interrupt: + mov r6, #4 + b reset + +prefetch_abort: + mov r6, #5 + b reset + +data_abort: + mov r6, #6 + b reset + +not_used: + /* we *should* never reach this */ + mov r6, #7 + b reset + +irq: + mov r6, #8 + b reset + +fiq: + mov r6, #9 + b reset |