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Diffstat (limited to 'arch/arm/cpu/armv7/start.S')
| -rw-r--r-- | arch/arm/cpu/armv7/start.S | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S new file mode 100644 index 0000000..1e0a150 --- /dev/null +++ b/arch/arm/cpu/armv7/start.S @@ -0,0 +1,416 @@ +/* + * armboot - Startup Code for OMAP3530/ARM Cortex CPU-core + * + * Copyright (c) 2004 Texas Instruments <r-woodruff2@ti.com> + * + * Copyright (c) 2001 Marius Gröger <mag@sysgo.de> + * Copyright (c) 2002 Alex Züpke <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) 2006-2008 Syed Mohammed Khasim <x0khasim@ti.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> + +.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 +_pad: .word 0x12345678 /* now 16*4=64 */ +.global _end_vect +_end_vect: + + .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 + * + *************************************************************************/ + +_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, #0xd3 + msr cpsr,r0 + +#if (CONFIG_OMAP34XX) + /* Copy vectors to mask ROM indirect addr */ + adr r0, _start @ r0 <- current position of code + add r0, r0, #4 @ skip reset vector + mov r2, #64 @ r2 <- size to copy + add r2, r0, r2 @ r2 <- source end address + mov r1, #SRAM_OFFSET0 @ build vect addr + mov r3, #SRAM_OFFSET1 + add r1, r1, r3 + mov r3, #SRAM_OFFSET2 + add r1, r1, r3 +next: + ldmia r0!, {r3 - r10} @ copy from source address [r0] + stmia r1!, {r3 - r10} @ copy to target address [r1] + cmp r0, r2 @ until source end address [r2] + bne next @ loop until equal */ +#if !defined(CONFIG_SYS_NAND_BOOT) && !defined(CONFIG_SYS_ONENAND_BOOT) + /* No need to copy/exec the clock code - DPLL adjust already done + * in NAND/oneNAND Boot. + */ + bl cpy_clk_code @ put dpll adjust code behind vectors +#endif /* NAND Boot */ +#endif + /* the mask ROM code should have PLL and others stable */ +#ifndef CONFIG_SKIP_LOWLEVEL_INIT + bl cpu_init_crit +#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: @ copy 32 bytes at a time + 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 +#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 + bic sp, sp, #7 @ 8-byte alignment for ABI compliance + + /* Clear BSS (if any). Is below tx (watch load addr - need space) */ +clear_bss: + ldr r0, _bss_start @ find start of bss segment + ldr r1, _bss_end @ stop here + mov r2, #0x00000000 @ clear value +clbss_l: + str r2, [r0] @ clear BSS location + cmp r0, r1 @ are we at the end yet + add r0, r0, #4 @ increment clear index pointer + bne clbss_l @ keep clearing till at end + + ldr pc, _start_armboot @ jump to C code + +_start_armboot: .word start_armboot + + +/************************************************************************* + * + * CPU_init_critical registers + * + * setup important registers + * setup memory timing + * + *************************************************************************/ +cpu_init_crit: + /* + * Invalidate L1 I/D + */ + mov r0, #0 @ set up for MCR + mcr p15, 0, r0, c8, c7, 0 @ invalidate TLBs + mcr p15, 0, r0, c7, c5, 0 @ invalidate icache + + /* + * disable MMU stuff and caches + */ + mrc p15, 0, r0, c1, c0, 0 + bic r0, r0, #0x00002000 @ clear bits 13 (--V-) + bic r0, r0, #0x00000007 @ clear bits 2:0 (-CAM) + orr r0, r0, #0x00000002 @ set bit 1 (--A-) Align + orr r0, r0, #0x00000800 @ set bit 12 (Z---) BTB + mcr p15, 0, r0, c1, c0, 0 + + /* + * Jump to board specific initialization... + * The Mask ROM will have already initialized + * basic memory. Go here to bump up clock rate and handle + * wake up conditions. + */ + mov ip, lr @ persevere link reg across call + bl lowlevel_init @ go setup pll,mux,memory + mov lr, ip @ restore link + mov pc, lr @ back to my caller +/* + ************************************************************************* + * + * 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 @ carve out a frame on current + @ user stack + stmia sp, {r0 - r12} @ Save user registers (now in + @ svc mode) r0-r12 + + ldr r2, _armboot_start + sub r2, r2, #(CONFIG_SYS_MALLOC_LEN) + sub r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE + 8) @ set base 2 words into abort + @ stack + ldmia r2, {r2 - r3} @ get values for "aborted" pc + @ and cpsr (into parm regs) + add r0, sp, #S_FRAME_SIZE @ grab pointer to old stack + + add r5, sp, #S_SP + mov r1, lr + stmia r5, {r0 - r3} @ save sp_SVC, lr_SVC, pc, cpsr + mov r0, sp @ save current stack into r0 + @ (param register) + .endm + + .macro irq_save_user_regs + sub sp, sp, #S_FRAME_SIZE + stmia sp, {r0 - r12} @ Calling r0-r12 + add r8, sp, #S_PC @ !! R8 NEEDS to be saved !! + @ a reserved stack spot would + @ be good. + 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_start @ setup our mode stack (enter + @ in banked mode) + sub r13, r13, #(CONFIG_SYS_MALLOC_LEN) @ move past malloc pool + sub r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE + 8) @ move to reserved a couple + @ spots for abort stack + + str lr, [r13] @ save caller lr in position 0 + @ of saved stack + mrs lr, spsr @ get the spsr + str lr, [r13, #4] @ save spsr in position 1 of + @ saved stack + + mov r13, #MODE_SVC @ prepare SVC-Mode + @ msr spsr_c, r13 + msr spsr, r13 @ switch modes, make sure + @ moves will execute + mov lr, pc @ capture return pc + movs pc, lr @ jump to next instruction & + @ switch modes. + .endm + + .macro get_bad_stack_swi + sub r13, r13, #4 @ space on current stack for + @ scratch reg. + str r0, [r13] @ save R0's value. + ldr r0, _armboot_start @ get data regions start + sub r0, r0, #(CONFIG_SYS_MALLOC_LEN) @ move past malloc pool + sub r0, r0, #(CONFIG_SYS_GBL_DATA_SIZE + 8) @ move past gbl and a couple + @ spots for abort stack + str lr, [r0] @ save caller lr in position 0 + @ of saved stack + mrs r0, spsr @ get the spsr + str lr, [r0, #4] @ save spsr in position 1 of + @ saved stack + ldr r0, [r13] @ restore r0 + add r13, r13, #4 @ pop stack entry + .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_swi + 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 effective 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 |