start.s

U-boot源码 ARM7启动代码

/*
 * Copyright (C) 2003	Josef Baumgartner <[e-mail]>
 * Based on code from Bernhard Kuhn <[e-mail]>
 *
 * 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"

#ifndef	 CONFIG_IDENT_STRING
#define	 CONFIG_IDENT_STRING ""
#endif

#define _START	_start
#define _FAULT	_fault

#define SAVE_ALL						\
	move.w	#0x2700,%sr;		/* disable intrs */	\
	subl	#60,%sp;		/* space for 15 regs */ \
	moveml	%d0-%d7/%a0-%a6,%sp@;

#define RESTORE_ALL						\
	moveml	%sp@,%d0-%d7/%a0-%a6;				\
	addl	#60,%sp;		/* space for 15 regs */ \
	rte;

.text
/*
 *	Vector table. This is used for initial platform startup.
 *	These vectors are to catch any un-intended traps.
 */
_vectors:

INITSP:		.long	0x00000000	/* Initial SP	*/
INITPC:		.long	_START	/* Initial PC 		*/
vector02:	.long	_FAULT	/* Access Error		*/
vector03:	.long	_FAULT	/* Address Error	*/
vector04:	.long	_FAULT	/* Illegal Instruction	*/
vector05:	.long	_FAULT	/* Reserved		*/
vector06:	.long	_FAULT	/* Reserved		*/
vector07:	.long	_FAULT	/* Reserved		*/
vector08:	.long	_FAULT	/* Privilege Violation	*/
vector09:	.long	_FAULT	/* Trace		*/
vector0A:	.long	_FAULT	/* Unimplemented A-Line	*/
vector0B:	.long	_FAULT	/* Unimplemented F-Line	*/
vector0C:	.long	_FAULT	/* Debug Interrupt	*/
vector0D:	.long	_FAULT	/* Reserved		*/
vector0E:	.long	_FAULT	/* Format Error		*/
vector0F:	.long	_FAULT	/* Unitialized Int.	*/

/* Reserved */
vector10_17:
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT

vector18:	.long	_FAULT	/* Spurious Interrupt	*/
vector19:	.long	_FAULT	/* Autovector Level 1	*/
vector1A:	.long	_FAULT	/* Autovector Level 2	*/
vector1B:	.long	_FAULT	/* Autovector Level 3	*/
vector1C:	.long	_FAULT	/* Autovector Level 4	*/
vector1D:	.long	_FAULT	/* Autovector Level 5	*/
vector1E:	.long	_FAULT	/* Autovector Level 6	*/
vector1F:	.long	_FAULT	/* Autovector Level 7	*/

/* TRAP #0 - #15 */
vector20_2F:
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT

/* Reserved	*/
vector30_3F:
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT

vector64_127:
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT

vector128_191:
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT

vector192_255:
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT
.long	_FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT, _FAULT

	.text

	.globl	_start
_start:
	nop
	nop
	move.w #0x2700,%sr	/* Mask off Interrupt */

	/* Set vector base register at the beginning of the Flash */
	move.l	#CFG_FLASH_BASE, %d0
	movec	%d0, %VBR

	move.l	#(CFG_INIT_RAM_ADDR + CFG_INIT_RAM_CTRL), %d0
	movec	%d0, %RAMBAR1

	/* invalidate and disable cache */
	move.l	#0x01000000, %d0		/* Invalidate cache cmd */
	movec	%d0, %CACR			/* Invalidate cache */
	move.l	#0, %d0
	movec	%d0, %ACR0
	movec	%d0, %ACR1

	/* initialize general use internal ram */
	move.l #0, %d0
	move.l #(CFG_INIT_RAM_ADDR+CFG_INIT_RAM_END-8), %a1
	move.l #(CFG_INIT_RAM_ADDR+CFG_INIT_RAM_END-4), %a2
	move.l %d0, (%a1)
	move.l %d0, (%a2)

	/* set stackpointer to end of internal ram to get some stackspace for the
	   first c-code */
	move.l	#(CFG_INIT_RAM_ADDR + CFG_INIT_SP_OFFSET), %sp
	clr.l %sp@-

	move.l #__got_start, %a5	/* put relocation table address to a5 */

	bsr cpu_init_f			/* run low-level CPU init code (from flash) */
	bsr board_init_f		/* run low-level board init code (from flash) */

	/* board_init_f() does not return */

/*------------------------------------------------------------------------------*/

/*
 * void relocate_code (addr_sp, gd, addr_moni)
 *
 * This "function" does not return, instead it continues in RAM
 * after relocating the monitor code.
 *
 * r3 = dest
 * r4 = src
 * r5 = length in bytes
 * r6 = cachelinesize
 */
	.globl	relocate_code
relocate_code:
	link.w %a6,#0
	move.l 8(%a6), %sp		/* set new stack pointer */

	move.l 12(%a6), %d0		/* Save copy of Global Data pointer */
	move.l 16(%a6), %a0		/* Save copy of Destination Address */

	move.l #CFG_MONITOR_BASE, %a1
	move.l #__init_end, %a2
	move.l %a0, %a3

	/* copy the code to RAM */
1:
	move.l (%a1)+, (%a3)+
	cmp.l  %a1,%a2
	bgt.s	 1b

/*
 * We are done. Do not return, instead branch to second part of board
 * initialization, now running from RAM.
 */
	move.l	%a0, %a1
	add.l	#(in_ram - CFG_MONITOR_BASE), %a1
	jmp	(%a1)

in_ram:

clear_bss:
	/*
	 * Now clear BSS segment
	 */
	move.l	%a0, %a1
	add.l	#(_sbss - CFG_MONITOR_BASE),%a1
	move.l	%a0, %d1
	add.l	#(_ebss - CFG_MONITOR_BASE),%d1
6:
	clr.l	(%a1)+
	cmp.l	%a1,%d1
	bgt.s	6b

	/*
	 * fix got table in RAM
	 */
	move.l	%a0, %a1
	add.l	#(__got_start - CFG_MONITOR_BASE),%a1
	move.l	%a1,%a5		/* * fix got pointer register a5 */

	move.l	%a0, %a2
	add.l	#(__got_end - CFG_MONITOR_BASE),%a2

7:
	move.l	(%a1),%d1
	sub.l	#_start,%d1
	add.l	%a0,%d1
	move.l	%d1,(%a1)+
	cmp.l	%a2, %a1
	bne	7b

	/* calculate relative jump to board_init_r in ram */
	move.l %a0, %a1
	add.l #(board_init_r - CFG_MONITOR_BASE), %a1

	/* set parameters for board_init_r */
	move.l %a0,-(%sp)		/* dest_addr */
	move.l %d0,-(%sp)		/* gd */
	jsr	(%a1)

/*------------------------------------------------------------------------------*/
/* exception code */
	.globl _fault
_fault:
	jmp _fault
	.globl	_exc_handler

_exc_handler:
	SAVE_ALL
	movel	%sp,%sp@-
	bsr exc_handler
	addql	#4,%sp
	RESTORE_ALL

	.globl	_int_handler
_int_handler:
	SAVE_ALL
	movel	%sp,%sp@-
	bsr int_handler
	addql	#4,%sp
	RESTORE_ALL

/*------------------------------------------------------------------------------*/
/* cache functions */
	.globl	icache_enable
icache_enable:
	move.l	#0x01000000, %d0		/* Invalidate cache cmd */
	movec	%d0, %CACR			/* Invalidate cache */
	move.l	#(CFG_SDRAM_BASE + 0x1c000), %d0
	movec	%d0, %ACR0			/* Enable cache */

	move.l	#0x80000200, %d0		/* Setup cache mask */
	movec	%d0, %CACR			/* Enable cache */
	nop

	move.l #(CFG_INIT_RAM_ADDR+CFG_INIT_RAM_END-8), %a1
	moveq	#1, %d0
	move.l	%d0, (%a1)
	rts

	.globl	icache_disable
icache_disable:
	move.l	#0x01000000, %d0		/* Setup cache mask */
	movec	%d0, %CACR			/* Disable cache */
	clr.l	%d0				/* Setup cache mask */
	movec	%d0, %ACR0
	movec	%d0, %ACR1

	move.l #(CFG_INIT_RAM_ADDR+CFG_INIT_RAM_END-8), %a1
	moveq	#0, %d0
	move.l	%d0, (%a1)
	rts

	.globl	icache_status
icache_status:
	move.l #(CFG_INIT_RAM_ADDR+CFG_INIT_RAM_END-8), %a1
	move.l	(%a1), %d0
	rts

	.globl	icache_invalid
icache_invalid:
	move.l	#0x81000200, %d0		/* Setup cache mask */
	movec	%d0, %CACR			/* Enable cache */
	rts

	.globl	dcache_enable
dcache_enable:
	move.l #(CFG_INIT_RAM_ADDR+CFG_INIT_RAM_END-4), %a1
	moveq	#1, %d0
	move.l	%d0, (%a1)
	rts

    /* No dcache, just a dummy function */
	.globl	dcache_disable
dcache_disable:
	move.l #(CFG_INIT_RAM_ADDR+CFG_INIT_RAM_END-4), %a1
	moveq	#0, %d0
	move.l	%d0, (%a1)
	rts

	.globl	dcache_status
dcache_status:
	move.l #(CFG_INIT_RAM_ADDR+CFG_INIT_RAM_END-4), %a1
	move.l	(%a1), %d0
	rts

/*------------------------------------------------------------------------------*/

	.globl	version_string
version_string:
	.ascii U_BOOT_VERSION
	.ascii " (", __DATE__, " - ", __TIME__, ")"
	.ascii CONFIG_IDENT_STRING, "\0"