/* * Early initialization code for ARMv7 architecture. * * This file is based off of the OMAP3530/ARM Cortex start.S file from Das * U-Boot, which itself got the file from armboot. * * Copyright (c) 2004 Texas Instruments * Copyright (c) 2001 Marius Gröger * Copyright (c) 2002 Alex Züpke * Copyright (c) 2002 Gary Jennejohn * Copyright (c) 2003 Richard Woodruff * Copyright (c) 2003 Kshitij * Copyright (c) 2006-2008 Syed Mohammed Khasim * Copyright (c) 2013 The Chromium OS Authors * * 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 */ #define __ASSEMBLY__ #include .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 */ .balignl 16,0xdeadbeef reset: /* * set the cpu to SVC32 mode */ mrs r0, cpsr bic r0, r0, #0x1f orr r0, r0, #0xd3 msr cpsr,r0 /* * From Cortex-A Series Programmer's Guide: * Only CPU 0 performs initialization. Other CPUs go into WFI * to do this, first work out which CPU this is * this code typically is run before any other initialization step */ mrc p15, 0, r1, c0, c0, 5 @ Read Multiprocessor Affinity Register and r1, r1, #0x3 @ Extract CPU ID bits cmp r1, #0 bne wait_for_interrupt @ If this is not core0, wait /* Set V=0 in CP15 SCTRL register - for VBAR to point to vector */ mrc p15, 0, r0, c1, c0, 0 @ Read CP15 SCTRL Register bic r0, #CR_V @ V = 0 mcr p15, 0, r0, c1, c0, 0 @ Write CP15 SCTRL Register /* Set vector address in CP15 VBAR register */ ldr r0, =_start mcr p15, 0, r0, c12, c0, 0 @Set VBAR /* Set stackpointer in internal RAM to call board_init_f */ call_board_init_f: ldr sp, =(CONFIG_SYS_INIT_SP_ADDR) mov sp, r0 bic sp, sp, #7 /* 8-byte alignment for ABI compliance */ ldr r0,=0x00000000 bl board_init_f wait_for_interrupt: wfi mov pc, lr @ back to my caller