xmodem.c

Intel PXA270的bootloader程序,在linux环境下运行的.

#include <stdio.h>
#include <setup.h>
#include <time.h>
#include <command.h>
#include <string.h>
#include "types.h"

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

#define report(fmt, args...)		printf(fmt, ##args)
#define assert(fmt, args...)		//printf(fmt, ##args)
#define failed(fmt, args...)		//printf(fmt, ##args)

static int xmodem_recv(void *addr, uint size);
static void *recv_block(void *buff, int size);
static bool ignore_data(int size);
static uint16 xmodem_crc(void *addr, int len);
extern int uart_getb(void);
extern int uart_putb(int ch);

static inline int xmodem_getb(int timeout){
	int ch;
	clock_t end;
	end = clock() + CLOCKS_PER_SEC * timeout;
	while (clock() < end){
		ch = uart_getb();
		if (ch >= 0) return ch;
	}
	return -1;
}

static inline int xmodem_putb(int ch){
	return uart_putb(ch);
}

static void xmodem_usage(void){
	usage_format("xmodem {loader/kernel/ramdisk/root}", "receive file with xmodem");
	usage_format("xmodem address", "receive file with xmodem");
	return;
}

static bool do_xmodem(int argc, char **argv){
	int received;
	ulong maxsize=0, tmp;
	void *addr;
	struct map *mp;

	if (argc != 2) goto invalid;
	mp = find_map(argv[1]);
	if (mp){
		addr = (void *)mp->dramb;
		maxsize = mp->maxs;
	} else if (strtoul(argv[1], &tmp, 16)){
		addr = (void *)tmp;
		maxsize = -1;
	} else goto invalid;

	received = xmodem_recv(addr, maxsize);
	report("\r                                               \r");
	report("\r                                               \r");

	if (!received)
		report(" xmodem : failed. not received.\n");
	else if (received > maxsize)
		report(" xmodem : failed. file size is too big.\n");
	else if (received)
		report(" xmodem : %d (0x%08X) bytes received.\n", received, received);

	if (mp) mp->drams = received;
	if (!received || received > maxsize)
		return false;
	return true;
invalid :
	xmodem_usage();
	return false;
}

struct command_t cmd_xmodem = {
	.name  = "xmodem",
	.run   = do_xmodem,
	.usage = xmodem_usage
};


static int xmodem_recv(void *addr, uint maxsize){
	int ch;
	int received;

	int retry;
	uchar buff[1024], *dest=addr, *s;

	int blksize=0;
	int blknum1, blknum2, lastblk;
//	uint8 blknum1, blknum2, lastblk;
	uint16 crc1, crc2, crcu, crcl;

	received = 0;
	lastblk = 0;
	retry = 20;
	while (retry > 0){ 
		if (!received) xmodem_putb('C');

		ch = xmodem_getb(1);
		if (ch < 0){ retry--; continue; }
		retry = 1;

		if (ch == SOH){
			blksize = 128;
		} else if (ch == STX){
			blksize = 1024;
		} else if (ch == EOT){
			xmodem_putb(ACK);
			break;
		} else return 0;

		blknum1 = xmodem_getb(1);
		if (blknum1 < 0) break;
		blknum2 = xmodem_getb(1);
		if (blknum2 < 0) break;

		if (blknum1 != (uint8)~blknum2)
			goto cancel;

		if (blknum1 == (uint8)lastblk){
			ignore_data(blksize + 2);
			xmodem_putb(ACK);
			continue;
		}
		if (blknum1 != (uint8)(lastblk + 1))
			goto cancel;

		lastblk++;

		recv_block(buff, blksize);

		if (maxsize - blksize < 0) goto cancel;
		memcpy(dest, buff, blksize);
		dest += blksize;
		maxsize -= blksize;
		received += blksize;

		crc1 = xmodem_crc(buff, blksize);
		crcu = xmodem_getb(1);
		crcl = xmodem_getb(1);
		crc2 = (crcu << 8) | crcl;

		ch = (crc1 == crc2) ? ACK : NAK;
		xmodem_putb(ch);
	}
	s = (uchar *)addr + received - 1;	/* remove pad (0x1A) */
	while (*s == 0x1A) s--;
	return s - (uchar *)addr + 1;

cancel :
	xmodem_putb(CAN);
	while (xmodem_getb(1) >= 0);
	return 0;
}

static bool ignore_data(int size){
	int ch;
	while (size--){
		ch = xmodem_getb(1);
		if (ch < 0) return false;
	}
	return true;
}

static void *recv_block(void *buff, int size){
	int ch;
	uchar *s = buff;

	while (size-- > 0){
		ch = xmodem_getb(1);
		if (ch < 0) return 0;
		*s++ = ch;
	}
	return buff;
}

static uint16 xmodem_crc(void *addr, int len){
	int i;
	uint16 crc;
	uchar *s = addr;

	crc = 0;
	while (len-- > 0){
		crc = crc ^ ((int)*s++ << 8);
		for (i=0; i < 8; i++)
			crc = (crc & 0x8000) ? crc << 1 ^ 0x1021 : crc << 1;
	}
	return crc;
}