amiflop.c

linux和2410结合开发 用他可以生成2410所需的zImage文件

			return 0;
		}
	}
	unit[drive].track = 0;
	ms_delay(unit[drive].type->settle_time);

	rel_fdc();
	fd_deselect(drive);
	return 1;
}

static int fd_seek(int drive, int track)
{
	unsigned char prb;
	int cnt;

#ifdef DEBUG
	printk("seeking drive %d to track %d\n",drive,track);
#endif
	drive &= 3;
	get_fdc(drive);
	if (unit[drive].track == track) {
		rel_fdc();
		return 1;
	}
	if (!fd_motor_on(drive)) {
		rel_fdc();
		return 0;
	}
	if (unit[drive].track < 0 && !fd_calibrate(drive)) {
		rel_fdc();
		return 0;
	}

	fd_select (drive);
	cnt = unit[drive].track/2 - track/2;
	prb = ciab.prb;
	prb |= DSKSIDE | DSKDIREC;
	if (track % 2 != 0)
		prb &= ~DSKSIDE;
	if (cnt < 0) {
		cnt = - cnt;
		prb &= ~DSKDIREC;
	}
	ciab.prb = prb;
	if (track % 2 != unit[drive].track % 2)
		ms_delay (unit[drive].type->side_time);
	unit[drive].track = track;
	if (cnt == 0) {
		rel_fdc();
		fd_deselect(drive);
		return 1;
	}
	do {
		prb &= ~DSKSTEP;
		ciab.prb = prb;
		prb |= DSKSTEP;
		udelay (1);
		ciab.prb = prb;
		ms_delay (unit[drive].type->step_delay);
	} while (--cnt != 0);
	ms_delay (unit[drive].type->settle_time);

	rel_fdc();
	fd_deselect(drive);
	return 1;
}

static unsigned long fd_get_drive_id(int drive)
{
	int i;
	ulong id = 0;

  	drive&=3;
  	get_fdc(drive);
	/* set up for ID */
	MOTOR_ON;
	udelay(2);
	SELECT(SELMASK(drive));
	udelay(2);
	DESELECT(SELMASK(drive));
	udelay(2);
	MOTOR_OFF;
	udelay(2);
	SELECT(SELMASK(drive));
	udelay(2);
	DESELECT(SELMASK(drive));
	udelay(2);

	/* loop and read disk ID */
	for (i=0; i<32; i++) {
		SELECT(SELMASK(drive));
		udelay(2);

		/* read and store value of DSKRDY */
		id <<= 1;
		id |= (ciaa.pra & DSKRDY) ? 0 : 1;	/* cia regs are low-active! */

		DESELECT(SELMASK(drive));
	}

	rel_fdc();

        /*
         * RB: At least A500/A2000's df0: don't identify themselves.
         * As every (real) Amiga has at least a 3.5" DD drive as df0:
         * we default to that if df0: doesn't identify as a certain
         * type.
         */
        if(drive == 0 && id == FD_NODRIVE)
	{
                id = fd_def_df0;
                printk(KERN_NOTICE "fd: drive 0 didn't identify, setting default %08lx\n", (ulong)fd_def_df0);
	}
	/* return the ID value */
	return (id);
}

static void fd_block_done(int irq, void *dummy, struct pt_regs *fp)
{
	if (block_flag)
		custom.dsklen = 0x4000;

	if (block_flag == 2) { /* writing */
		writepending = 2;
		post_write_timer.expires = jiffies + 1; /* at least 2 ms */
		post_write_timer.data = selected;
		add_timer(&post_write_timer);
	}
	else {                /* reading */
		block_flag = 0;
		wake_up (&wait_fd_block);
	}
}

static void raw_read(int drive)
{
	drive&=3;
	get_fdc(drive);
	while (block_flag)
		sleep_on(&wait_fd_block);
	fd_select(drive);
	/* setup adkcon bits correctly */
	custom.adkcon = ADK_MSBSYNC;
	custom.adkcon = ADK_SETCLR|ADK_WORDSYNC|ADK_FAST;

	custom.dsksync = MFM_SYNC;

	custom.dsklen = 0;
	custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
	custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;
	custom.dsklen = unit[drive].type->read_size/sizeof(short) | DSKLEN_DMAEN;

	block_flag = 1;

	while (block_flag)
		sleep_on (&wait_fd_block);

	custom.dsklen = 0;
	fd_deselect(drive);
	rel_fdc();
}

static int raw_write(int drive)
{
	ushort adk;

	drive&=3;
	get_fdc(drive); /* corresponds to rel_fdc() in post_write() */
	if ((ciaa.pra & DSKPROT) == 0) {
		rel_fdc();
		return 0;
	}
	while (block_flag)
		sleep_on(&wait_fd_block);
	fd_select(drive);
	/* clear adkcon bits */
	custom.adkcon = ADK_PRECOMP1|ADK_PRECOMP0|ADK_WORDSYNC|ADK_MSBSYNC;
	/* set appropriate adkcon bits */
	adk = ADK_SETCLR|ADK_FAST;
	if ((ulong)unit[drive].track >= unit[drive].type->precomp2)
		adk |= ADK_PRECOMP1;
	else if ((ulong)unit[drive].track >= unit[drive].type->precomp1)
		adk |= ADK_PRECOMP0;
	custom.adkcon = adk;

	custom.dsklen = DSKLEN_WRITE;
	custom.dskptr = (u_char *)ZTWO_PADDR((u_char *)raw_buf);
	custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;
	custom.dsklen = unit[drive].type->write_size/sizeof(short) | DSKLEN_DMAEN|DSKLEN_WRITE;

	block_flag = 2;
	return 1;
}

/*
 * to be called at least 2ms after the write has finished but before any
 * other access to the hardware.
 */
static void post_write (unsigned long drive)
{
#ifdef DEBUG
	printk("post_write for drive %ld\n",drive);
#endif
	drive &= 3;
	custom.dsklen = 0;
	block_flag = 0;
	writepending = 0;
	writefromint = 0;
	unit[drive].dirty = 0;
	wake_up(&wait_fd_block);
	fd_deselect(drive);
	rel_fdc(); /* corresponds to get_fdc() in raw_write */
}


/*
 * The following functions are to convert the block contents into raw data
 * written to disk and vice versa.
 * (Add other formats here ;-))
 */

static unsigned long scan_sync(unsigned long raw, unsigned long end)
{
	ushort *ptr = (ushort *)raw, *endp = (ushort *)end;

	while (ptr < endp && *ptr++ != 0x4489)
		;
	if (ptr < endp) {
		while (*ptr == 0x4489 && ptr < endp)
			ptr++;
		return (ulong)ptr;
	}
	return 0;
}

static inline unsigned long checksum(unsigned long *addr, int len)
{
	unsigned long csum = 0;

	len /= sizeof(*addr);
	while (len-- > 0)
		csum ^= *addr++;
	csum = ((csum>>1) & 0x55555555)  ^  (csum & 0x55555555);

	return csum;
}

static unsigned long decode (unsigned long *data, unsigned long *raw,
			     int len)
{
	ulong *odd, *even;

	/* convert length from bytes to longwords */
	len >>= 2;
	odd = raw;
	even = odd + len;

	/* prepare return pointer */
	raw += len * 2;

	do {
		*data++ = ((*odd++ & 0x55555555) << 1) | (*even++ & 0x55555555);
	} while (--len != 0);

	return (ulong)raw;
}

struct header {
	unsigned char magic;
	unsigned char track;
	unsigned char sect;
	unsigned char ord;
	unsigned char labels[16];
	unsigned long hdrchk;
	unsigned long datachk;
};

static int amiga_read(int drive)
{
	unsigned long raw;
	unsigned long end;
	int scnt;
	unsigned long csum;
	struct header hdr;

	drive&=3;
	raw = (long) raw_buf;
	end = raw + unit[drive].type->read_size;

	for (scnt = 0;scnt < unit[drive].dtype->sects * unit[drive].type->sect_mult; scnt++) {
		if (!(raw = scan_sync(raw, end))) {
			printk (KERN_INFO "can't find sync for sector %d\n", scnt);
			return MFM_NOSYNC;
		}

		raw = decode ((ulong *)&hdr.magic, (ulong *)raw, 4);
		raw = decode ((ulong *)&hdr.labels, (ulong *)raw, 16);
		raw = decode ((ulong *)&hdr.hdrchk, (ulong *)raw, 4);
		raw = decode ((ulong *)&hdr.datachk, (ulong *)raw, 4);
		csum = checksum((ulong *)&hdr,
				(char *)&hdr.hdrchk-(char *)&hdr);

#ifdef DEBUG
		printk ("(%x,%d,%d,%d) (%lx,%lx,%lx,%lx) %lx %lx\n",
			hdr.magic, hdr.track, hdr.sect, hdr.ord,
			*(ulong *)&hdr.labels[0], *(ulong *)&hdr.labels[4],
			*(ulong *)&hdr.labels[8], *(ulong *)&hdr.labels[12],
			hdr.hdrchk, hdr.datachk);
#endif

		if (hdr.hdrchk != csum) {
			printk(KERN_INFO "MFM_HEADER: %08lx,%08lx\n", hdr.hdrchk, csum);
			return MFM_HEADER;
		}

		/* verify track */
		if (hdr.track != unit[drive].track) {
			printk(KERN_INFO "MFM_TRACK: %d, %d\n", hdr.track, unit[drive].track);
			return MFM_TRACK;
		}

		raw = decode ((ulong *)(unit[drive].trackbuf + hdr.sect*512),
			      (ulong *)raw, 512);
		csum = checksum((ulong *)(unit[drive].trackbuf + hdr.sect*512), 512);

		if (hdr.datachk != csum) {
			printk(KERN_INFO "MFM_DATA: (%x:%d:%d:%d) sc=%d %lx, %lx\n",
			       hdr.magic, hdr.track, hdr.sect, hdr.ord, scnt,
			       hdr.datachk, csum);
			printk (KERN_INFO "data=(%lx,%lx,%lx,%lx)\n",
				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[0],
				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[1],
				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[2],
				((ulong *)(unit[drive].trackbuf+hdr.sect*512))[3]);
			return MFM_DATA;
		}
	}

	return 0;
}

static void encode(unsigned long data, unsigned long *dest)
{
	unsigned long data2;

	data &= 0x55555555;
	data2 = data ^ 0x55555555;
	data |= ((data2 >> 1) | 0x80000000) & (data2 << 1);

	if (*(dest - 1) & 0x00000001)
		data &= 0x7FFFFFFF;

	*dest = data;
}

static void encode_block(unsigned long *dest, unsigned long *src, int len)
{
	int cnt, to_cnt = 0;
	unsigned long data;

	/* odd bits */
	for (cnt = 0; cnt < len / 4; cnt++) {
		data = src[cnt] >> 1;
		encode(data, dest + to_cnt++);
	}

	/* even bits */
	for (cnt = 0; cnt < len / 4; cnt++) {
		data = src[cnt];
		encode(data, dest + to_cnt++);
	}
}

static unsigned long *putsec(int disk, unsigned long *raw, int cnt)
{
	struct header hdr;
	int i;

	disk&=3;
	*raw = (raw[-1]&1) ? 0x2AAAAAAA : 0xAAAAAAAA;
	raw++;
	*raw++ = 0x44894489;

	hdr.magic = 0xFF;
	hdr.track = unit[disk].track;
	hdr.sect = cnt;
	hdr.ord = unit[disk].dtype->sects * unit[disk].type->sect_mult - cnt;
	for (i = 0; i < 16; i++)
		hdr.labels[i] = 0;
	hdr.hdrchk = checksum((ulong *)&hdr,
			      (char *)&hdr.hdrchk-(char *)&hdr);
	hdr.datachk = checksum((ulong *)(unit[disk].trackbuf+cnt*512), 512);

	encode_block(raw, (ulong *)&hdr.magic, 4);
	raw += 2;
	encode_block(raw, (ulong *)&hdr.labels, 16);
	raw += 8;
	encode_block(raw, (ulong *)&hdr.hdrchk, 4);
	raw += 2;
	encode_block(raw, (ulong *)&hdr.datachk, 4);
	raw += 2;
	encode_block(raw, (ulong *)(unit[disk].trackbuf+cnt*512), 512);
	raw += 256;

	return raw;
}

static void amiga_write(int disk)
{
	unsigned int cnt;
	unsigned long *ptr = (unsigned long *)raw_buf;

	disk&=3;
	/* gap space */
	for (cnt = 0; cnt < 415 * unit[disk].type->sect_mult; cnt++)
		*ptr++ = 0xaaaaaaaa;

	/* sectors */
	for (cnt = 0; cnt < unit[disk].dtype->sects * unit[disk].type->sect_mult; cnt++)
		ptr = putsec (disk, ptr, cnt);
	*(ushort *)ptr = (ptr[-1]&1) ? 0x2AA8 : 0xAAA8;
}


struct dos_header {
	unsigned char track,   /* 0-80 */
		side,    /* 0-1 */
		sec,     /* 0-...*/
		len_desc;/* 2 */
	unsigned short crc;     /* on 68000 we got an alignment problem, 
				   but this compiler solves it  by adding silently 
				   adding a pad byte so data won't fit
				   and this took about 3h to discover.... */
	unsigned char gap1[22];     /* for longword-alignedness (0x4e) */
};

/* crc routines are borrowed from the messydos-handler  */

/* excerpt from the messydos-device           
; The CRC is computed not only over the actual data, but including
; the SYNC mark (3 * $a1) and the 'ID/DATA - Address Mark' ($fe/$fb).
; As we don't read or encode these fields into our buffers, we have to
; preload the registers containing the CRC with the values they would have
; after stepping over these fields.
;
; How CRCs "really" work:
;
; First, you should regard a bitstring as a series of coefficients of
; polynomials. We calculate with these polynomials in modulo-2
; arithmetic, in which both add and subtract are done the same as
; exclusive-or. Now, we modify our data (a very long polynomial) in
; such a way that it becomes divisible by the CCITT-standard 16-bit
;		 16   12   5
; polynomial:	x  + x	+ x + 1, represented by $11021. The easiest
; way to do this would be to multiply (using proper arithmetic) our
; datablock with $11021. So we have:
;   data * $11021		 =
;   data * ($10000 + $1021)      =
;   data * $10000 + data * $1021
; The left part of this is simple: Just add two 0 bytes. But then
; the right part (data $1021) remains difficult and even could have
; a carry into the left part. The solution is to use a modified
; multiplication, which has a result that is not correct, but with
; a difference of any multiple of $11021. We then only need to keep
; the 16 least significant bits of the result.
;
; The following algorithm does this for us:
;
;   unsigned char *data, c, crclo, crchi;
;   while (not done) {
;	c = *data++ + crchi;
;	crchi = (@ c) >> 8 + crclo;
;	crclo = @ c;
;   }
;
; Remember, + is done with EOR, the @ operator is in two tables (high