e06ca69b2f
via xmodem to the DBGU port when the AT91 comes up in recovery mode. The recovery loader will then load your program via xmodem into SDRAM at 1MB which can do its things. It needs to be tweaked to the specific board one is using, but it fits in < 1kB (all of Atmel's ARM products have at least 8kb of SRAM that I can tell, so this should work for them all). Parts of this code were provided by Kwikbyte with copyright specifically disclaimed. I heavily modified it to act as a recovery loader (before it was a bootstrap loader) and to optimize for size (before I started the size was closer to 8k). Bootstrap loaders for SPI and IIC to follow.
77 lines
2.6 KiB
C
77 lines
2.6 KiB
C
/*-
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* Copyright (c) 2006 M. Warner Losh. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* This software is derived from software provided by kwikbyte without
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* copyright as follows:
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*
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* No warranty, expressed or implied, is included with this software. It is
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* provided "AS IS" and no warranty of any kind including statutory or aspects
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* relating to merchantability or fitness for any purpose is provided. All
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* intellectual property rights of others is maintained with the respective
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* owners. This software is not copyrighted and is intended for reference
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* only.
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*
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* $FreeBSD$
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*/
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#include "AT91RM9200.h"
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#include "at91rm9200_lowlevel.h"
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/*
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* void putc(int ch)
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* Writes a character to the DBGU port. It assumes that DBGU has
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* already been initialized.
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*/
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void
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putc(int ch)
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{
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AT91PS_USART pUSART = (AT91PS_USART)AT91C_BASE_DBGU;
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while (!(pUSART->US_CSR & AT91C_US_TXRDY))
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continue;
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pUSART->US_THR = (ch & 0xFF);
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}
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/*
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* int getc(int seconds)
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*
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* Reads a character from the DBGU port, if one is available within about
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* seconds seconds. It assumes that DBGU has already been initialized.
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*/
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int
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getc(int seconds)
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{
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AT91PS_USART pUSART = (AT91PS_USART)AT91C_BASE_DBGU;
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unsigned thisSecond;
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thisSecond = GetSeconds();
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seconds = thisSecond + seconds;
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while (thisSecond <= seconds) {
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if ((pUSART->US_CSR & AT91C_US_RXRDY))
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return (pUSART->US_RHR & 0xFF);
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thisSecond = GetSeconds();
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}
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return (-1);
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}
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