acrn-kernel/arch/avr32/boot/u-boot/head.S

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[PATCH] avr32 architecture This adds support for the Atmel AVR32 architecture as well as the AT32AP7000 CPU and the AT32STK1000 development board. AVR32 is a new high-performance 32-bit RISC microprocessor core, designed for cost-sensitive embedded applications, with particular emphasis on low power consumption and high code density. The AVR32 architecture is not binary compatible with earlier 8-bit AVR architectures. The AVR32 architecture, including the instruction set, is described by the AVR32 Architecture Manual, available from http://www.atmel.com/dyn/resources/prod_documents/doc32000.pdf The Atmel AT32AP7000 is the first CPU implementing the AVR32 architecture. It features a 7-stage pipeline, 16KB instruction and data caches and a full Memory Management Unit. It also comes with a large set of integrated peripherals, many of which are shared with the AT91 ARM-based controllers from Atmel. Full data sheet is available from http://www.atmel.com/dyn/resources/prod_documents/doc32003.pdf while the CPU core implementation including caches and MMU is documented by the AVR32 AP Technical Reference, available from http://www.atmel.com/dyn/resources/prod_documents/doc32001.pdf Information about the AT32STK1000 development board can be found at http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3918 including a BSP CD image with an earlier version of this patch, development tools (binaries and source/patches) and a root filesystem image suitable for booting from SD card. Alternatively, there's a preliminary "getting started" guide available at http://avr32linux.org/twiki/bin/view/Main/GettingStarted which provides links to the sources and patches you will need in order to set up a cross-compiling environment for avr32-linux. This patch, as well as the other patches included with the BSP and the toolchain patches, is actively supported by Atmel Corporation. [dmccr@us.ibm.com: Fix more pxx_page macro locations] [bunk@stusta.de: fix `make defconfig'] Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Dave McCracken <dmccr@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 14:32:13 +08:00
/*
* Startup code for use with the u-boot bootloader.
*
* Copyright (C) 2004-2006 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <asm/setup.h>
/*
* The kernel is loaded where we want it to be and all caches
* have just been flushed. We get two parameters from u-boot:
*
* r12 contains a magic number (ATAG_MAGIC)
* r11 points to a tag table providing information about
* the system.
*/
.section .init.text,"ax"
.global _start
_start:
/* Check if the boot loader actually provided a tag table */
lddpc r0, magic_number
cp.w r12, r0
brne no_tag_table
/* Initialize .bss */
lddpc r2, bss_start_addr
lddpc r3, end_addr
mov r0, 0
mov r1, 0
1: st.d r2++, r0
cp r2, r3
brlo 1b
/*
* Save the tag table address for later use. This must be done
* _after_ .bss has been initialized...
*/
lddpc r0, tag_table_addr
st.w r0[0], r11
/* Jump to loader-independent setup code */
rjmp kernel_entry
.align 2
magic_number:
.long ATAG_MAGIC
tag_table_addr:
.long bootloader_tags
bss_start_addr:
.long __bss_start
end_addr:
.long _end
no_tag_table:
sub r12, pc, (. - 2f)
bral panic
2: .asciz "Boot loader didn't provide correct magic number\n"