x-loader/cpu/arm1136/start.S

/*
 *  armboot - Startup Code for OMP2420/ARM1136 CPU-core
 *
 *  Copyright (c) 2004  Texas Instruments
 *
 *  Copyright (c) 2001	Marius Gröger <mag@sysgo.de>
 *  Copyright (c) 2002	Alex Züpke <azu@sysgo.de>
 *  Copyright (c) 2002	Gary Jennejohn <gj@denx.de>
 *  Copyright (c) 2003	Richard Woodruff <r-woodruff2@ti.com>
 *  Copyright (c) 2003	Kshitij <kshitij@ti.com>
 *  Copyright (c) 2004	Jian Zhang <jzhang@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>

.globl _start
_start:	
	b	reset
 	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang
	ldr	pc, _hang

_hang:
 	.word do_hang
	
	.word 0x12345678
	.word 0x12345678
	.word 0x12345678
	.word 0x12345678
	.word 0x12345678
	.word 0x12345678
	.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

/*
 * 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

	/* 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, #0x40000000         /* build vect addr */
	mov     r3, #0x00200000
	add     r1, r1, r3
	mov     r3, #0xf800
	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 */

	bl	cpy_clk_code            /* put dpll adjust code behind vectors */
 
	/* the mask ROM code should have PLL and others stable */
	bl  cpu_init_crit

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

	/* Set up the stack						    */
stack_setup:
	ldr	r0, _TEXT_BASE		/* upper 128 KiB: relocated uboot   */
	sub	sp, r0, #128		/* leave 32 words for abort-stack    */

clear_bss:
	ldr	r0, _bss_start		/* find start of bss segment        */
	ldr	r1, _bss_end		/* stop here                        */
	mov 	r2, #0x00000000		/* clear                            */

//clbss_l:str	r2, [r0]		/* clear loop...                    */
//	add	r0, r0, #4
//	cmp	r0, r1
//	bne	clbss_l

	ldr	pc, _start_armboot

_start_armboot:	.word start_armboot


/*
 *************************************************************************
 *
 * CPU_init_critical registers
 *
 * setup important registers
 * setup memory timing
 *
 *************************************************************************
 */
cpu_init_crit:
	/*
	 * flush v4 I/D caches
	 */
	mov	r0, #0
	mcr	p15, 0, r0, c7, c7, 0	/* flush v3/v4 cache */
	mcr	p15, 0, r0, c8, c7, 0	/* flush v4 TLB */

	/*
	 * disable MMU stuff and caches
	 */
	mrc	p15, 0, r0, c1, c0, 0
	bic	r0, r0, #0x00002300	@ clear bits 13, 9:8 (--V- --RS)
	bic	r0, r0, #0x00000087	@ clear bits 7, 2:0 (B--- -CAM)
	orr	r0, r0, #0x00000002	@ set bit 2 (A) Align
#ifndef CONFIG_ICACHE_OFF
	orr	r0, r0, #0x00001000	@ set bit 12 (I) I-Cache
#endif
	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.
	 */
	adr	r0, _start		/* r0 <- current position of code   */
	ldr	r1, _TEXT_BASE		/* test if we run from flash or RAM */
	cmp     r0, r1                  /* pass on info about skipping some init portions */
	moveq   r0,#0x1                 /* flag to skip prcm and sdrc setup */
	movne   r0,#0x0

//mov r0, #1    /* this skip memory init */

	mov	ip, lr          /* persevere link reg across call */
	bl	platformsetup   /* go setup pll,mux,memory */

	mov	lr, ip          /* restore link */
	mov	pc, lr          /* back to my caller */


/*
 * exception handler
 */
 	.align  5
do_hang:
	ldr	sp, _TEXT_BASE		/* use 32 words abort stack */
   	bl	hang				/* hang and never return */