mfmhd.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

			DBG("mfm: end_request for CURRENT=0x%p CURRENT(sector=%d current_nr_sectors=%d nr_sectors=%d)\n",
				       CURRENT, CURRENT->sector, CURRENT->current_nr_sectors, CURRENT->nr_sectors);

			CURRENT->nr_sectors -= CURRENT->current_nr_sectors;
			CURRENT->sector += CURRENT->current_nr_sectors;
			SectorsLeftInRequest -= CURRENT->current_nr_sectors;

			end_request(1);
			if (SectorsLeftInRequest) {
				hdc63463_dataptr = (unsigned int) CURRENT->buffer;
				Copy_buffer = CURRENT->buffer;
				Sectors256LeftInCurrent = CURRENT->current_nr_sectors * 2;
				errors = &(CURRENT->errors);
				/* These should match the present calculations of the next logical sector
				   on the device
				   Copy_Sector=CURRENT->sector*2; */

				if (Copy_Sector != CURRENT->sector * 2)
#ifdef DEBUG
					/*console_printf*/printk("mfm: Copy_Sector mismatch. Copy_Sector=%d CURRENT->sector*2=%d\n",
					Copy_Sector, CURRENT->sector * 2);
#else
					printk("mfm: Copy_Sector mismatch! Eek!\n");
#endif
			};	/* CURRENT */
		};	/* Sectors256LeftInCurrent */
	};

	old_status = mfm_status;
	mfm_status = inw(MFM_STATUS);
	if (mfm_status & (STAT_DER | STAT_ABN)) {
		/* Something has gone wrong - let's try that again */
		if (cont) {
			DBG("mfm_rw_intr: DER/ABN error\n");
			cont->error();
			cont->redo();
		};
		return;
	};

	/* If this code wasn't entered due to command_end but there is
	   now a command end we must read the command results out. If it was
	   entered like this then mfm_interrupt_handler would have done the
	   job. */
	if ((!((old_status & (STAT_CPR | STAT_BSY)) == STAT_CPR)) &&
	    ((mfm_status & (STAT_CPR | STAT_BSY)) == STAT_CPR)) {
		int len = 0;
		while (len < 16) {
			int in;
			in = inw(MFM_DATAIN);
			result[len++] = in >> 8;
			result[len++] = in;
		};
	};			/* Result read */

	/*console_printf ("mfm_rw_intr nearexit [%02X]\n", __raw_readb(mfm_IRQPollLoc)); */

	/* If end of command move on */
	if (mfm_status & (STAT_CED)) {
		outw(CMD_RCAL, MFM_COMMAND);	/* Clear interrupt condition */
		/* End of command - trigger the next command */
		if (cont) {
			cont->done(1);
		}
		DBG("mfm_rw_intr: returned from cont->done\n");
	} else {
		/* Its going to generate another interrupt */
		SET_INTR(mfm_rw_intr);
	};
}

static void mfm_setup_rw(void)
{
	DBG("setting up for rw...\n");

	SET_INTR(mfm_rw_intr);
	issue_command(raw_cmd.cmdcode, raw_cmd.cmddata, raw_cmd.cmdlen);
}

static void mfm_recal_intr(void)
{
#ifdef DEBUG
	console_printf("recal intr - status = ");
	print_status();
#endif
	outw(CMD_RCAL, MFM_COMMAND);	/* Clear interrupt condition */
	if (mfm_status & (STAT_DER | STAT_ABN)) {
		printk("recal failed\n");
		MFM_DRV_INFO.cylinder = NEED_2_RECAL;
		if (cont) {
			cont->error();
			cont->redo();
		}
		return;
	}
	/* Thats seek end - we are finished */
	if (mfm_status & STAT_SED) {
		issue_command(CMD_POD, NULL, 0);
		MFM_DRV_INFO.cylinder = 0;
		mfm_seek();
		return;
	}
	/* Command end without seek end (see data sheet p.20) for parallel seek
	   - we have to send a POL command to wait for the seek */
	if (mfm_status & STAT_CED) {
		SET_INTR(mfm_recal_intr);
		issue_command(CMD_POL, NULL, 0);
		return;
	}
	printk("recal: unknown status\n");
}

static void mfm_seek_intr(void)
{
#ifdef DEBUG
	console_printf("seek intr - status = ");
	print_status();
#endif
	outw(CMD_RCAL, MFM_COMMAND);	/* Clear interrupt condition */
	if (mfm_status & (STAT_DER | STAT_ABN)) {
		printk("seek failed\n");
		MFM_DRV_INFO.cylinder = NEED_2_RECAL;
		if (cont) {
			cont->error();
			cont->redo();
		}
		return;
	}
	if (mfm_status & STAT_SED) {
		issue_command(CMD_POD, NULL, 0);
		MFM_DRV_INFO.cylinder = raw_cmd.cylinder;
		mfm_seek();
		return;
	}
	if (mfm_status & STAT_CED) {
		SET_INTR(mfm_seek_intr);
		issue_command(CMD_POL, NULL, 0);
		return;
	}
	printk("seek: unknown status\n");
}

/* IDEA2 seems to work better - its what RiscOS sets my
 * disc to - on its SECOND call to specify!
 */
#define IDEA2
#ifndef IDEA2
#define SPEC_SL 0x16
#define SPEC_SH 0xa9		/* Step pulse high=21, Record Length=001 (256 bytes) */
#else
#define SPEC_SL 0x00		/* OM2 - SL - step pulse low */
#define SPEC_SH 0x21		/* Step pulse high=4, Record Length=001 (256 bytes) */
#endif

static void mfm_setupspecify (int drive, unsigned char *cmdb)
{
	cmdb[0]  = 0x1f;		/* OM0 - !SECT,!MOD,!DIF,PADP,ECD,CRCP,CRCI,ACOR */
	cmdb[1]  = 0xc3;		/* OM1 - DTM,BRST,!CEDM,!SEDM,!DERM,0,AMEX,PSK */
	cmdb[2]  = SPEC_SL;		/* OM2 - SL - step pulse low */
	cmdb[3]  = (number_mfm_drives == 1) ? 0x02 : 0x06;	/* 1 or 2 drives */
	cmdb[4]  = 0xfc | ((mfm_info[drive].cylinders - 1) >> 8);/* RW time over/high part of number of cylinders */
	cmdb[5]  = mfm_info[drive].cylinders - 1;		/* low part of number of cylinders */
	cmdb[6]  = mfm_info[drive].heads - 1;			/* Number of heads */
	cmdb[7]  = mfm_info[drive].sectors - 1;			/* Number of sectors */
	cmdb[8]  = SPEC_SH;
	cmdb[9]  = 0x0a;		/* gap length 1 */
	cmdb[10] = 0x0d;		/* gap length 2 */
	cmdb[11] = 0x0c;		/* gap length 3 */
	cmdb[12] = (mfm_info[drive].precomp - 1) >> 8;	/* pre comp cylinder */
	cmdb[13] = mfm_info[drive].precomp - 1;
	cmdb[14] = (mfm_info[drive].lowcurrent - 1) >> 8;	/* Low current cylinder */
	cmdb[15] = mfm_info[drive].lowcurrent - 1;
}

static void mfm_specify (void)
{
	unsigned char cmdb[16];

	DBG("specify...dev=%d lastspecified=%d\n", raw_cmd.dev, lastspecifieddrive);
	mfm_setupspecify (raw_cmd.dev, cmdb);

	issue_command (CMD_SPC, cmdb, 16);
	/* Ensure that we will do another specify if we move to the other drive */
	lastspecifieddrive = raw_cmd.dev;
	wait_for_completion();
}

static void mfm_seek(void)
{
	unsigned char cmdb[4];

	DBG("seeking...\n");
	if (MFM_DRV_INFO.cylinder < 0) {
		SET_INTR(mfm_recal_intr);
		DBG("mfm_seek: about to call specify\n");
		mfm_specify ();	/* DAG added this */

		cmdb[0] = raw_cmd.dev + 1;
		cmdb[1] = 0;

		issue_command(CMD_RCLB, cmdb, 2);
		return;
	}
	if (MFM_DRV_INFO.cylinder != raw_cmd.cylinder) {
		cmdb[0] = raw_cmd.dev + 1;
		cmdb[1] = 0;	/* raw_cmd.head; DAG: My data sheet says this should be 0 */
		cmdb[2] = raw_cmd.cylinder >> 8;
		cmdb[3] = raw_cmd.cylinder;

		SET_INTR(mfm_seek_intr);
		issue_command(CMD_SEK, cmdb, 4);
	} else
		mfm_setup_rw();
}

static void mfm_initialise(void)
{
	DBG("init...\n");
	mfm_seek();
}

static void request_done(int uptodate)
{
	DBG("mfm:request_done\n");
	if (uptodate) {
		unsigned char block[2] = {0, 0};

		/* Apparently worked - let's check bytes left to DMA */
		if (hdc63463_dataleft != (PartFragRead_SectorsLeft * 256)) {
			printk("mfm: request_done - dataleft=%d - should be %d - Eek!\n", hdc63463_dataleft, PartFragRead_SectorsLeft * 256);
			end_request(0);
			Busy = 0;
		};
		/* Potentially this means that we've done; but we might be doing
		   a partial access, (over two cylinders) or we may have a number
		   of fragments in an image file.  First let's deal with partial accesss
		 */
		if (PartFragRead) {
			/* Yep - a partial access */

			/* and issue the remainder */
			issue_request(MINOR(CURRENT->rq_dev), PartFragRead_RestartBlock, PartFragRead_SectorsLeft, CURRENT);
			return;
		}

		/* ah well - perhaps there is another fragment to go */

		/* Increment pointers/counts to start of next fragment */
		if (SectorsLeftInRequest > 0) printk("mfm: SectorsLeftInRequest>0 - Eek! Shouldn't happen!\n");

		/* No - its the end of the line */
		/* end_request's should have happened at the end of sector DMAs */
		/* Turns Drive LEDs off - may slow it down? */
		if (QUEUE_EMPTY)
			issue_command(CMD_CKV, block, 2);

		Busy = 0;
		DBG("request_done: About to mfm_request\n");
		/* Next one please */
		mfm_request();	/* Moved from mfm_rw_intr */
		DBG("request_done: returned from mfm_request\n");
	} else {
		printk("mfm:request_done: update=0\n");
		end_request(0);
		Busy = 0;
	}
}

static void error_handler(void)
{
	printk("error detected... status = ");
	print_status();
	(*errors)++;
	if (*errors > MFM_DRV_INFO.errors.abort)
		cont->done(0);
	if (*errors > MFM_DRV_INFO.errors.recal)
		MFM_DRV_INFO.cylinder = NEED_2_RECAL;
}

static void rw_interrupt(void)
{
	printk("rw_interrupt\n");
}

static struct cont rw_cont =
{
	rw_interrupt,
	error_handler,
	mfm_rerequest,
	request_done
};

/*
 * Actually gets round to issuing the request - note everything at this
 * point is in 256 byte sectors not Linux 512 byte blocks
 */
static void issue_request(int dev, unsigned int block, unsigned int nsect,
			  struct request *req)
{
	int track, start_head, start_sector;
	int sectors_to_next_cyl;

	dev >>= 6;

	track = block / mfm_info[dev].sectors;
	start_sector = block % mfm_info[dev].sectors;
	start_head = track % mfm_info[dev].heads;

	/* First get the number of whole tracks which are free before the next
	   track */
	sectors_to_next_cyl = (mfm_info[dev].heads - (start_head + 1)) * mfm_info[dev].sectors;
	/* Then add in the number of sectors left on this track */
	sectors_to_next_cyl += (mfm_info[dev].sectors - start_sector);

	DBG("issue_request: mfm_info[dev].sectors=%d track=%d\n", mfm_info[dev].sectors, track);

	raw_cmd.dev = dev;
	raw_cmd.sector = start_sector;
	raw_cmd.head = start_head;
	raw_cmd.cylinder = track / mfm_info[dev].heads;
	raw_cmd.cmdtype = CURRENT->cmd;
	raw_cmd.cmdcode = CURRENT->cmd == WRITE ? CMD_WD : CMD_RD;
	raw_cmd.cmddata[0] = dev + 1;	/* DAG: +1 to get US */
	raw_cmd.cmddata[1] = raw_cmd.head;
	raw_cmd.cmddata[2] = raw_cmd.cylinder >> 8;
	raw_cmd.cmddata[3] = raw_cmd.cylinder;
	raw_cmd.cmddata[4] = raw_cmd.head;
	raw_cmd.cmddata[5] = raw_cmd.sector;

	/* Was == and worked - how the heck??? */
	if (lastspecifieddrive != raw_cmd.dev)
		mfm_specify ();

	if (nsect <= sectors_to_next_cyl) {
		raw_cmd.cmddata[6] = nsect >> 8;
		raw_cmd.cmddata[7] = nsect;
		PartFragRead = 0;	/* All in one */
		PartFragRead_SectorsLeft = 0;	/* Must set this - used in DMA calcs */
	} else {
		raw_cmd.cmddata[6] = sectors_to_next_cyl >> 8;
		raw_cmd.cmddata[7] = sectors_to_next_cyl;
		PartFragRead = sectors_to_next_cyl;	/* only do this many this time */
		PartFragRead_RestartBlock = block + sectors_to_next_cyl;	/* Where to restart from */
		PartFragRead_SectorsLeft = nsect - sectors_to_next_cyl;
	}
	raw_cmd.cmdlen = 8;

	/* Setup DMA pointers */
	hdc63463_dataptr = (unsigned int) Copy_buffer;
	hdc63463_dataleft = nsect * 256;	/* Better way? */

	DBG("mfm%c: %sing: CHS=%d/%d/%d, sectors=%d, buffer=0x%08lx (%p)\n",
	     raw_cmd.dev + 'a', (CURRENT->cmd == READ) ? "read" : "writ",
		       raw_cmd.cylinder,
		       raw_cmd.head,
	    raw_cmd.sector, nsect, (unsigned long) Copy_buffer, CURRENT);

	cont = &rw_cont;
	errors = &(CURRENT->errors);
#if 0
	mfm_tq.routine = (void (*)(void *)) mfm_initialise;
	queue_task(&mfm_tq, &tq_immediate);
	mark_bh(IMMEDIATE_BH);
#else
	mfm_initialise();
#endif
}				/* issue_request */

/*
 * Called when an error has just happened - need to trick mfm_request
 * into thinking we weren't busy
 *
 * Turn off ints - mfm_request expects them this way
 */
static void mfm_rerequest(void)
{
	DBG("mfm_rerequest\n");
	cli();
	Busy = 0;
	mfm_request();
}

static void mfm_request(void)
{
	DBG("mfm_request CURRENT=%p Busy=%d\n", CURRENT, Busy);

	if (QUEUE_EMPTY) {
		DBG("mfm_request: Exited due to NULL Current 1\n");
		return;
	}

	if (CURRENT->rq_status == RQ_INACTIVE) {
		/* Hmm - seems to be happening a lot on 1.3.45 */
		/*console_printf("mfm_request: Exited due to INACTIVE Current\n"); */
		return;
	}

	/* If we are still processing then return; we will get called again */
	if (Busy) {
		/* Again seems to be common in 1.3.45 */
		/*DBG*/printk("mfm_request: Exiting due to busy\n");
		return;
	}
	Busy = 1;

	while (1) {
		unsigned int dev, block, nsect;

		DBG("mfm_request: loop start\n");
		sti();

		DBG("mfm_request: before INIT_REQUEST\n");

		if (QUEUE_EMPTY) {
			printk("mfm_request: Exiting due to !CURRENT (pre)\n");
			CLEAR_INTR;
			Busy = 0;
			return;
		};

		INIT_REQUEST;

		DBG("mfm_request:                 before arg extraction\n");

		dev = MINOR(CURRENT->rq_dev);
		block = CURRENT->sector;
		nsect = CURRENT->nr_sectors;
#ifdef DEBUG
		/*if ((dev>>6)==1) */ console_printf("mfm_request:                                raw vals: dev=%d (block=512 bytes) block=%d nblocks=%d\n", dev, block, nsect);
#endif
		if (dev >= (mfm_drives << 6) ||
		    block >= mfm[dev].nr_sects || ((block+nsect) > mfm[dev].nr_sects)) {
			if (dev >= (mfm_drives << 6))
				printk("mfm: bad minor number: device=%s\n", kdevname(CURRENT->rq_dev));
			else
				printk("mfm%c: bad access: block=%d, count=%d, nr_sects=%ld\n", (dev >> 6)+'a',
				       block, nsect, mfm[dev].nr_sects);
			printk("mfm: continue 1\n");
			end_request(0);
			Busy = 0;
			continue;
		}

		block += mfm[dev].start_sect;

		/* DAG: Linux doesn't cope with this - even though it has an array telling
		   it the hardware block size - silly */
		block <<= 1;	/* Now in 256 byte sectors */
		nsect <<= 1;	/* Ditto */

		SectorsLeftInRequest = nsect >> 1;
		Sectors256LeftInCurrent = CURRENT->current_nr_sectors * 2;
		Copy_buffer = CURRENT->buffer;
		Copy_Sector = CURRENT->sector << 1;

		DBG("mfm_request: block after offset=%d\n", block);

		if (CURRENT->cmd != READ && CURRENT->cmd != WRITE) {
			printk("unknown mfm-command %d\n", CURRENT->cmd);
			end_request(0);
			Busy = 0;
			printk("mfm: continue 4\n");
			continue;
		}
		issue_request(dev, block, nsect, CURRENT);

		break;
	}
	DBG("mfm_request: Dropping out bottom\n");
}

static void do_mfm_request(request_queue_t *q)
{
	DBG("do_mfm_request: about to mfm_request\n");
	mfm_request();
}

static void mfm_interrupt_handler(int unused, void *dev_id, struct pt_regs *regs)
{
	void (*handler) (void) = DEVICE_INTR;

	CLEAR_INTR;

	DBG("mfm_interrupt_handler (handler=0x%p)\n", handler);

	mfm_status = inw(MFM_STATUS);

	/* If CPR (Command Parameter Reject) and not busy it means that the command
	   has some return message to give us */
	if ((mfm_status & (STAT_CPR | STAT_BSY)) == STAT_CPR) {
		int len = 0;
		while (len < 16) {
			int in;
			in = inw(MFM_DATAIN);
			result[len++] = in >> 8;
			result[len++] = in;
		}
	}
	if (handler) {
		handler();
		return;
	}
	outw (CMD_RCAL, MFM_COMMAND);	/* Clear interrupt condition */
	printk ("mfm: unexpected interrupt - status = ");
	print_status ();
	while (1);
}