xmodem.c

arm7s3c44b0x0里ps2口和lcd口驱动编程实例

/*-------------------------------------------------------------------------
 * Filename:      xmodem.c
 * Version:       $Id: xmodem.c,v 1.2 2002/01/06 19:02:29 erikm Exp $
 * Copyright:     Copyright (C) 2001, Hewlett-Packard Company
 * Author:        Christopher Hoover <[e-mail]>
 * Description:   xmodem functionality for uploading of kernels 
 *                and the like
 * Created at:    Thu Dec 20 01:58:08 PST 2001
 *-----------------------------------------------------------------------*/
/*
 * xmodem.c: xmodem functionality for uploading of kernels and 
 *            the like
 *
 * Copyright (C) 2001 Hewlett-Packard Laboratories
 *
 * 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
 *
 */

#ident "$Id: xmodem.c,v 1.2 2002/01/06 19:02:29 erikm Exp $"


#include "\inc\drives.h"

#define	UART_RD_TMOUT	300000
#define TIMEOUT 		800
#define MAXERRORS		10	//5

#define	serial_write_raw(cc)	putch(cc)

static int SerialInputBlock(char *buf, unsigned long count, unsigned long timeout)
{
	if(!WaitEventWithTimeout(kbhit, 1, timeout)) 
	{
		*buf = getch();
		return 1;
	}
	return 0;
}


#define SOH 0x01
#define STX 0x02
#define EOT 0x04
#define ACK 0x06
#define NAK 0x15
#define CAN 0x18
#define BS  0x08

#undef	ERROR
#define ERROR(...) do { } while (0)

static char *blockBuf;			//使用指针,去掉copy过程

static __inline void WriteByte(char cc) 
{ 
	serial_write_raw(cc); 
}

int ReadByteWithTimeout(unsigned int timeout) 
{
	char buf[1];
	int n;

	n = SerialInputBlock(buf, 1, timeout);

	if (n == 1)
		return buf[0] & 0xff;
	else
		return -1;
}

static void ReadFlush() 
{
	while(ReadByteWithTimeout(1000)>=0);
}
  

int XModemReceive(char *bufBase, int bufLen)
{
	unsigned int errors = 0;
	unsigned int wantBlockNo = 1;
	unsigned int length = 0;
	int crc = 1;		//use crc by send 'C', use checksum by send NAK
	char nak = 'C';
	int crc_val;
	unsigned char expectedCksum;
		
		blockBuf = bufBase;		//将bufBase赋与blockBuf;

	ERROR("start xmodem!\n");
	
	ReadFlush();
	
	/* Ask for CRC; if we get errors, we will go with checksum */
	WriteByte(nak);
	ERROR("WriteByte(nak)\n");

	for (;;) 
	{
		int blockBegin;
		int blockNo, blockNoOnesCompl;
		int blockLength;
		int cksum = 0;
		int crcHi = 0;
		int crcLo = 0;

		blockBegin = ReadByteWithTimeout(TIMEOUT);
		if (blockBegin < 0)
		{
			ERROR("Read blockBegin timeout!\n");
			goto timeout;
		}

		nak = NAK;

		switch (blockBegin) 
		{
		case SOH:
		case STX:
			break;

		case EOT:
			WriteByte(ACK);
			ERROR("WriteByte(ACK): done\n");
			goto done;

		default:
			ERROR("blockBegin error!\n");
			errors--;
			goto error;
		}

		/* block no */
		blockNo = ReadByteWithTimeout(TIMEOUT);
		if (blockNo < 0)
		{
			ERROR("blockNo timeout!\n");
			goto timeout;
		}

		/* block no one's compliment */
		blockNoOnesCompl = ReadByteWithTimeout(TIMEOUT);
		if (blockNoOnesCompl < 0)
		{
			ERROR("blockNoOnesCompl timeout!\n");
			goto timeout;
		}

		if (blockNo != (255 - blockNoOnesCompl)) 
		{
			ERROR("bad block ones compl\n");
			goto error;
		}

		blockLength = (blockBegin == SOH) ? 128 : 1024;

		{
			int i, j;
			
			crc_val = 0;			
			expectedCksum = 0;

			for (i = 0; i < blockLength; i++) 
			{
				int cc = ReadByteWithTimeout(TIMEOUT);
				if (cc < 0)
				{
					ERROR(" read block byte timeout!\n");
					goto timeout;
				}
				blockBuf[i] = cc;		

				//crc 或 checksum 计算加在读数据后
				if (crc) 
				{
					crc_val = crc_val ^ cc << 8;
					for (j = 0; j < 8; j++)
						if (crc_val & 0x8000)
							crc_val = crc_val << 1 ^ 0x1021;
						else
							crc_val = crc_val << 1;
				} 
				else 
				{
					expectedCksum += cc;
				}
			}
		}

		if (crc) 
		{
			crcHi = ReadByteWithTimeout(TIMEOUT);
			if (crcHi < 0) 
			{
				ERROR(" read crcHi timeout!\n");
				goto timeout;
			}

			crcLo = ReadByteWithTimeout(TIMEOUT);
			if (crcLo < 0) 
			{
				ERROR(" read crcLo timeout!\n");
				goto timeout;
			}			
			
			if ((crcHi != ((crc_val>>8) & 0xff)) ||
			    (crcLo != (crc_val & 0xff))) 
			{
				ERROR("crc error!\n");
				goto error;
			}
			
		} 
		else 
		{
			cksum = ReadByteWithTimeout(TIMEOUT);
			if (cksum < 0)
			{
				ERROR(" read chksum timeout!\n");
				goto timeout;
			}
			
			if (cksum != expectedCksum) 
			{
				ERROR("checksum error! \n");
				goto error;
			}
		}

		if (blockNo == ((wantBlockNo - 1) & 0xff)) 
		{
			/* a repeat of the last block is ok, just ignore it. */
			/* this also ignores the initial block 0 which is */
			/* meta data. */
			goto next;
		} 
		else if (blockNo != (wantBlockNo & 0xff)) 
		{
			ERROR("unexpected block no! \n");
			goto error;
		}

		wantBlockNo++;
		length += blockLength;

		if (length > bufLen) 
		{
			ERROR("out of space\n");
			goto error;
		}

		blockBuf += blockLength;	//接收成功,指针加上收到字节数
next:
		errors = 0;
		WriteByte(ACK);
		ERROR("Receive one block OK!\n");
		continue;

error:
timeout:
		ERROR("Timeout.\n");
		errors++;
		if (errors == MAXERRORS) 
		{
			/* Abort */
			int i;

			// if using crc, try again w/o crc
			if (nak == 'C') 
			{
				nak = NAK;
				errors = 0;
				crc = 0;		//use checksum
				goto timeout;
			}
			
			for (i = 0; i < 5; i ++)
				WriteByte(CAN);
			for (i = 0; i < 5; i ++)
				WriteByte(BS);
			puts("too many errors; giving up\n");
			return -1;
		}

		ReadFlush();
		WriteByte(nak);
		ERROR("WriteByte(nak)\n");
	}

done:
	ERROR("\nxmodem done.\n");
	ReadFlush();
	return length;
}