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Diffstat (limited to 'cpu/at91rm9200/start.S')
| -rw-r--r-- | cpu/at91rm9200/start.S | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/cpu/at91rm9200/start.S b/cpu/at91rm9200/start.S new file mode 100644 index 0000000..9b3e7aa --- /dev/null +++ b/cpu/at91rm9200/start.S @@ -0,0 +1,347 @@ +/* + * armboot - Startup Code for ARM720 CPU-core + * + * Copyright (c) 2001 Marius Gröger <mag@sysgo.de> + * Copyright (c) 2002 Alex Züpke <azu@sysgo.de> + * + * 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 as in table 3.1 in [1] + * + ************************************************************************* + */ + + +.globl _start +_start: b reset + ldr pc, _undefined_instruction + ldr pc, _software_interrupt + ldr pc, _prefetch_abort + ldr pc, _data_abort + ldr pc, _not_used + ldr pc, _irq + ldr pc, _fiq + +_undefined_instruction: .word undefined_instruction +_software_interrupt: .word software_interrupt +_prefetch_abort: .word prefetch_abort +_data_abort: .word data_abort +_not_used: .word not_used +_irq: .word irq +_fiq: .word fiq + + .balignl 16,0xdeadbeef + + +/* + ************************************************************************* + * + * Startup Code (reset vector) + * + * do important init only if we don't start from memory! + * relocate armboot to ram + * setup stack + * jump to second stage + * + ************************************************************************* + */ + +/* + * CFG_MEM_END is in the board dependent config-file (configs/config_BOARD.h) + */ +_TEXT_BASE: + .word TEXT_BASE + +.globl _armboot_start +_armboot_start: + .word _start + +/* + * Note: _armboot_end_data and _armboot_end are defined + * by the (board-dependent) linker script. + * _armboot_end_data is the first usable FLASH address after armboot + */ +.globl _armboot_end_data +_armboot_end_data: + .word armboot_end_data +/* + * Note: armboot_end is defined by the (board-dependent) linker script + */ +.globl _armboot_end +_armboot_end: + .word armboot_end + +/* + * _armboot_real_end is the first usable RAM address behind armboot + * and the various stacks + */ +.globl _armboot_real_end +_armboot_real_end: + .word 0x0badc0de + +#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 + + /* + * relocate exeception table + */ + ldr r0, =_start + ldr r1, =0x0 + mov r2, #16 +copyex: + subs r2, r2, #1 + ldr r3, [r0], #4 + str r3, [r1], #4 + bne copyex + + /* + * we do sys-critical inits only at reboot, + * not when booting from ram! + */ +#ifdef CONFIG_INIT_CRITICAL + bl cpu_init_crit +#endif + + /* set up the stack */ + ldr r0, _armboot_end + add r0, r0, #CONFIG_STACKSIZE + sub sp, r0, #12 /* leave 3 words for abort-stack */ + ldr pc,_start_armboot + +_start_armboot: .word start_armboot + +/* + ************************************************************************* + * + * CPU_init_critical registers + * + ************************************************************************* + */ + +cpu_init_crit: + # actually do nothing for now! + mov pc, lr + + + + +/* + ************************************************************************* + * + * Interrupt handling + * + ************************************************************************* + */ + +@ +@ IRQ stack frame. +@ +#define S_FRAME_SIZE 72 + +#define S_OLD_R0 68 +#define S_PSR 64 +#define S_PC 60 +#define S_LR 56 +#define S_SP 52 + +#define S_IP 48 +#define S_FP 44 +#define S_R10 40 +#define S_R9 36 +#define S_R8 32 +#define S_R7 28 +#define S_R6 24 +#define S_R5 20 +#define S_R4 16 +#define S_R3 12 +#define S_R2 8 +#define S_R1 4 +#define S_R0 0 + +#define MODE_SVC 0x13 +#define I_BIT 0x80 + +/* + * use bad_save_user_regs for abort/prefetch/undef/swi ... + * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling + */ + + .macro bad_save_user_regs + sub sp, sp, #S_FRAME_SIZE + stmia sp, {r0 - r12} @ Calling r0-r12 + add r8, sp, #S_PC + + ldr r2, _armboot_end + add r2, r2, #CONFIG_STACKSIZE + sub r2, r2, #8 + ldmia r2, {r2 - r4} @ get pc, cpsr, old_r0 + add r0, sp, #S_FRAME_SIZE @ restore sp_SVC + + add r5, sp, #S_SP + mov r1, lr + stmia r5, {r0 - r4} @ save sp_SVC, lr_SVC, pc, cpsr, old_r + mov r0, sp + .endm + + .macro irq_save_user_regs + sub sp, sp, #S_FRAME_SIZE + stmia sp, {r0 - r12} @ Calling r0-r12 + add r8, sp, #S_PC + stmdb r8, {sp, lr}^ @ Calling SP, LR + str lr, [r8, #0] @ Save calling PC + mrs r6, spsr + str r6, [r8, #4] @ Save CPSR + str r0, [r8, #8] @ Save OLD_R0 + mov r0, sp + .endm + + .macro irq_restore_user_regs + ldmia sp, {r0 - lr}^ @ Calling r0 - lr + mov r0, r0 + ldr lr, [sp, #S_PC] @ Get PC + add sp, sp, #S_FRAME_SIZE + subs pc, lr, #4 @ return & move spsr_svc into cpsr + .endm + + .macro get_bad_stack + ldr r13, _armboot_end @ setup our mode stack + add r13, r13, #CONFIG_STACKSIZE @ resides at top of normal stack + sub r13, r13, #8 + + str lr, [r13] @ save caller lr / spsr + mrs lr, spsr + str lr, [r13, #4] + + mov r13, #MODE_SVC @ prepare SVC-Mode + msr spsr_c, r13 + mov lr, pc + movs pc, lr + .endm + + .macro get_irq_stack @ setup IRQ stack + ldr sp, IRQ_STACK_START + .endm + + .macro get_fiq_stack @ setup FIQ stack + ldr sp, FIQ_STACK_START + .endm + +/* + * exception handlers + */ + .align 5 +undefined_instruction: + get_bad_stack + bad_save_user_regs + bl do_undefined_instruction + + .align 5 +software_interrupt: + get_bad_stack + bad_save_user_regs + bl do_software_interrupt + + .align 5 +prefetch_abort: + get_bad_stack + bad_save_user_regs + bl do_prefetch_abort + + .align 5 +data_abort: + get_bad_stack + bad_save_user_regs + bl do_data_abort + + .align 5 +not_used: + get_bad_stack + bad_save_user_regs + bl do_not_used + +#ifdef CONFIG_USE_IRQ + + .align 5 +irq: + get_irq_stack + irq_save_user_regs + bl do_irq + irq_restore_user_regs + + .align 5 +fiq: + get_fiq_stack + /* someone ought to write a more effiction fiq_save_user_regs */ + irq_save_user_regs + bl do_fiq + irq_restore_user_regs + +#else + + .align 5 +irq: + get_bad_stack + bad_save_user_regs + bl do_irq + + .align 5 +fiq: + get_bad_stack + bad_save_user_regs + bl do_fiq + +#endif + + .align 5 +.globl reset_cpu +reset_cpu: + mov pc, r0 |