floppy.c

Linux块设备驱动源码

		return;
	if (fdc_dtr())
		return;

#ifdef DCL_DEBUG
	if (DP->flags & FD_DEBUG) {
		DPRINT("calling disk change from floppy_ready\n");
	}
#endif
	if (!(raw_cmd->flags & FD_RAW_NO_MOTOR) &&
	    disk_change(current_drive) && !DP->select_delay)
		twaddle();	/* this clears the dcl on certain drive/controller
				 * combinations */

#ifdef fd_chose_dma_mode
	if ((raw_cmd->flags & FD_RAW_READ) || (raw_cmd->flags & FD_RAW_WRITE)) {
		unsigned long flags = claim_dma_lock();
		fd_chose_dma_mode(raw_cmd->kernel_data, raw_cmd->length);
		release_dma_lock(flags);
	}
#endif

	if (raw_cmd->flags & (FD_RAW_NEED_SEEK | FD_RAW_NEED_DISK)) {
		perpendicular_mode();
		fdc_specify();	/* must be done here because of hut, hlt ... */
		seek_floppy();
	} else {
		if ((raw_cmd->flags & FD_RAW_READ) ||
		    (raw_cmd->flags & FD_RAW_WRITE))
			fdc_specify();
		setup_rw_floppy();
	}
}

static void floppy_start(void)
{
	reschedule_timeout(current_reqD, "floppy start", 0);

	scandrives();
#ifdef DCL_DEBUG
	if (DP->flags & FD_DEBUG) {
		DPRINT("setting NEWCHANGE in floppy_start\n");
	}
#endif
	SETF(FD_DISK_NEWCHANGE);
	floppy_ready();
}

/*
 * ========================================================================
 * here ends the bottom half. Exported routines are:
 * floppy_start, floppy_off, floppy_ready, lock_fdc, unlock_fdc, set_fdc,
 * start_motor, reset_fdc, reset_fdc_info, interpret_errors.
 * Initialization also uses output_byte, result, set_dor, floppy_interrupt
 * and set_dor.
 * ========================================================================
 */
/*
 * General purpose continuations.
 * ==============================
 */

static void do_wakeup(void)
{
	reschedule_timeout(MAXTIMEOUT, "do wakeup", 0);
	cont = NULL;
	command_status += 2;
	wake_up(&command_done);
}

static struct cont_t wakeup_cont = {
	.interrupt	= empty,
	.redo		= do_wakeup,
	.error		= empty,
	.done		= (done_f) empty
};

static struct cont_t intr_cont = {
	.interrupt	= empty,
	.redo		= process_fd_request,
	.error		= empty,
	.done		= (done_f) empty
};

static int wait_til_done(void (*handler) (void), int interruptible)
{
	int ret;

	schedule_bh(handler);

	if (command_status < 2 && NO_SIGNAL) {
		DECLARE_WAITQUEUE(wait, current);

		add_wait_queue(&command_done, &wait);
		for (;;) {
			set_current_state(interruptible ?
					  TASK_INTERRUPTIBLE :
					  TASK_UNINTERRUPTIBLE);

			if (command_status >= 2 || !NO_SIGNAL)
				break;

			is_alive("wait_til_done");

			schedule();
		}

		set_current_state(TASK_RUNNING);
		remove_wait_queue(&command_done, &wait);
	}

	if (command_status < 2) {
		cancel_activity();
		cont = &intr_cont;
		reset_fdc();
		return -EINTR;
	}

	if (FDCS->reset)
		command_status = FD_COMMAND_ERROR;
	if (command_status == FD_COMMAND_OKAY)
		ret = 0;
	else
		ret = -EIO;
	command_status = FD_COMMAND_NONE;
	return ret;
}

static void generic_done(int result)
{
	command_status = result;
	cont = &wakeup_cont;
}

static void generic_success(void)
{
	cont->done(1);
}

static void generic_failure(void)
{
	cont->done(0);
}

static void success_and_wakeup(void)
{
	generic_success();
	cont->redo();
}

/*
 * formatting and rw support.
 * ==========================
 */

static int next_valid_format(void)
{
	int probed_format;

	probed_format = DRS->probed_format;
	while (1) {
		if (probed_format >= 8 || !DP->autodetect[probed_format]) {
			DRS->probed_format = 0;
			return 1;
		}
		if (floppy_type[DP->autodetect[probed_format]].sect) {
			DRS->probed_format = probed_format;
			return 0;
		}
		probed_format++;
	}
}

static void bad_flp_intr(void)
{
	int err_count;

	if (probing) {
		DRS->probed_format++;
		if (!next_valid_format())
			return;
	}
	err_count = ++(*errors);
	INFBOUND(DRWE->badness, err_count);
	if (err_count > DP->max_errors.abort)
		cont->done(0);
	if (err_count > DP->max_errors.reset)
		FDCS->reset = 1;
	else if (err_count > DP->max_errors.recal)
		DRS->track = NEED_2_RECAL;
}

static void set_floppy(int drive)
{
	int type = ITYPE(UDRS->fd_device);
	if (type)
		_floppy = floppy_type + type;
	else
		_floppy = current_type[drive];
}

/*
 * formatting support.
 * ===================
 */
static void format_interrupt(void)
{
	switch (interpret_errors()) {
	case 1:
		cont->error();
	case 2:
		break;
	case 0:
		cont->done(1);
	}
	cont->redo();
}

#define CODE2SIZE (ssize = ((1 << SIZECODE) + 3) >> 2)
#define FM_MODE(x,y) ((y) & ~(((x)->rate & 0x80) >>1))
#define CT(x) ((x) | 0xc0)
static void setup_format_params(int track)
{
	struct fparm {
		unsigned char track, head, sect, size;
	} *here = (struct fparm *)floppy_track_buffer;
	int il, n;
	int count, head_shift, track_shift;

	raw_cmd = &default_raw_cmd;
	raw_cmd->track = track;

	raw_cmd->flags = FD_RAW_WRITE | FD_RAW_INTR | FD_RAW_SPIN |
	    FD_RAW_NEED_DISK | FD_RAW_NEED_SEEK;
	raw_cmd->rate = _floppy->rate & 0x43;
	raw_cmd->cmd_count = NR_F;
	COMMAND = FM_MODE(_floppy, FD_FORMAT);
	DR_SELECT = UNIT(current_drive) + PH_HEAD(_floppy, format_req.head);
	F_SIZECODE = FD_SIZECODE(_floppy);
	F_SECT_PER_TRACK = _floppy->sect << 2 >> F_SIZECODE;
	F_GAP = _floppy->fmt_gap;
	F_FILL = FD_FILL_BYTE;

	raw_cmd->kernel_data = floppy_track_buffer;
	raw_cmd->length = 4 * F_SECT_PER_TRACK;

	/* allow for about 30ms for data transport per track */
	head_shift = (F_SECT_PER_TRACK + 5) / 6;

	/* a ``cylinder'' is two tracks plus a little stepping time */
	track_shift = 2 * head_shift + 3;

	/* position of logical sector 1 on this track */
	n = (track_shift * format_req.track + head_shift * format_req.head)
	    % F_SECT_PER_TRACK;

	/* determine interleave */
	il = 1;
	if (_floppy->fmt_gap < 0x22)
		il++;

	/* initialize field */
	for (count = 0; count < F_SECT_PER_TRACK; ++count) {
		here[count].track = format_req.track;
		here[count].head = format_req.head;
		here[count].sect = 0;
		here[count].size = F_SIZECODE;
	}
	/* place logical sectors */
	for (count = 1; count <= F_SECT_PER_TRACK; ++count) {
		here[n].sect = count;
		n = (n + il) % F_SECT_PER_TRACK;
		if (here[n].sect) {	/* sector busy, find next free sector */
			++n;
			if (n >= F_SECT_PER_TRACK) {
				n -= F_SECT_PER_TRACK;
				while (here[n].sect)
					++n;
			}
		}
	}
	if (_floppy->stretch & FD_ZEROBASED) {
		for (count = 0; count < F_SECT_PER_TRACK; count++)
			here[count].sect--;
	}
}

static void redo_format(void)
{
	buffer_track = -1;
	setup_format_params(format_req.track << STRETCH(_floppy));
	floppy_start();
	debugt("queue format request");
}

static struct cont_t format_cont = {
	.interrupt	= format_interrupt,
	.redo		= redo_format,
	.error		= bad_flp_intr,
	.done		= generic_done
};

static int do_format(int drive, struct format_descr *tmp_format_req)
{
	int ret;

	LOCK_FDC(drive, 1);
	set_floppy(drive);
	if (!_floppy ||
	    _floppy->track > DP->tracks ||
	    tmp_format_req->track >= _floppy->track ||
	    tmp_format_req->head >= _floppy->head ||
	    (_floppy->sect << 2) % (1 << FD_SIZECODE(_floppy)) ||
	    !_floppy->fmt_gap) {
		process_fd_request();
		return -EINVAL;
	}
	format_req = *tmp_format_req;
	format_errors = 0;
	cont = &format_cont;
	errors = &format_errors;
	IWAIT(redo_format);
	process_fd_request();
	return ret;
}

/*
 * Buffer read/write and support
 * =============================
 */

static void floppy_end_request(struct request *req, int uptodate)
{
	unsigned int nr_sectors = current_count_sectors;

	/* current_count_sectors can be zero if transfer failed */
	if (!uptodate)
		nr_sectors = req->current_nr_sectors;
	if (end_that_request_first(req, uptodate, nr_sectors))
		return;
	add_disk_randomness(req->rq_disk);
	floppy_off((long)req->rq_disk->private_data);
	blkdev_dequeue_request(req);
	end_that_request_last(req);

	/* We're done with the request */
	current_req = NULL;
}

/* new request_done. Can handle physical sectors which are smaller than a
 * logical buffer */
static void request_done(int uptodate)
{
	struct request_queue *q = floppy_queue;
	struct request *req = current_req;
	unsigned long flags;
	int block;

	probing = 0;
	reschedule_timeout(MAXTIMEOUT, "request done %d", uptodate);

	if (!req) {
		printk("floppy.c: no request in request_done\n");
		return;
	}

	if (uptodate) {
		/* maintain values for invalidation on geometry
		 * change */
		block = current_count_sectors + req->sector;
		INFBOUND(DRS->maxblock, block);
		if (block > _floppy->sect)
			DRS->maxtrack = 1;

		/* unlock chained buffers */
		spin_lock_irqsave(q->queue_lock, flags);
		floppy_end_request(req, 1);
		spin_unlock_irqrestore(q->queue_lock, flags);
	} else {
		if (rq_data_dir(req) == WRITE) {
			/* record write error information */
			DRWE->write_errors++;
			if (DRWE->write_errors == 1) {
				DRWE->first_error_sector = req->sector;
				DRWE->first_error_generation = DRS->generation;
			}
			DRWE->last_error_sector = req->sector;
			DRWE->last_error_generation = DRS->generation;
		}
		spin_lock_irqsave(q->queue_lock, flags);
		floppy_end_request(req, 0);
		spin_unlock_irqrestore(q->queue_lock, flags);
	}
}

/* Interrupt handler evaluating the result of the r/w operation */
static void rw_interrupt(void)
{
	int nr_sectors, ssize, eoc, heads;

	if (R_HEAD >= 2) {
		/* some Toshiba floppy controllers occasionnally seem to
		 * return bogus interrupts after read/write operations, which
		 * can be recognized by a bad head number (>= 2) */
		return;
	}

	if (!DRS->first_read_date)
		DRS->first_read_date = jiffies;

	nr_sectors = 0;
	CODE2SIZE;

	if (ST1 & ST1_EOC)
		eoc = 1;
	else
		eoc = 0;

	if (COMMAND & 0x80)
		heads = 2;
	else
		heads = 1;

	nr_sectors = (((R_TRACK - TRACK) * heads +
		       R_HEAD - HEAD) * SECT_PER_TRACK +
		      R_SECTOR - SECTOR + eoc) << SIZECODE >> 2;

#ifdef FLOPPY_SANITY_CHECK
	if (nr_sectors / ssize >
	    (in_sector_offset + current_count_sectors + ssize - 1) / ssize) {
		DPRINT("long rw: %x instead of %lx\n",
		       nr_sectors, current_count_sectors);
		printk("rs=%d s=%d\n", R_SECTOR, SECTOR);
		printk("rh=%d h=%d\n", R_HEAD, HEAD);
		printk("rt=%d t=%d\n", R_TRACK, TRACK);
		printk("heads=%d eoc=%d\n", heads, eoc);
		printk("spt=%d st=%d ss=%d\n", SECT_PER_TRACK,
		       fsector_t, ssize);
		printk("in_sector_offset=%d\n", in_sector_offset);
	}
#endif

	nr_sectors -= in_sector_offset;
	INFBOUND(nr_sectors, 0);
	SUPBOUND(current_count_sectors, nr_sectors);

	switch (interpret_errors()) {
	case 2:
		cont->redo();
		return;
	case 1:
		if (!current_count_sectors) {
			cont->error();
			cont->redo();
			return;
		}
		break;
	case 0:
		if (!current_count_sectors) {
			cont->redo();
			return;
		}
		current_type[current_drive] = _floppy;
		floppy_sizes[TOMINOR(current_drive)] = _floppy->size;
		break;
	}

	if (probing) {
		if (DP->flags & FTD_MSG)
			DPRINT("Auto-detected floppy type %s in fd%d\n",
			       _floppy->name, current_drive);
		current_type[current_drive] = _floppy;
		floppy_sizes[TOMINOR(current_drive)] = _floppy->size;
		probing = 0;
	}

	if (CT(COMMAND) != FD_READ ||
	    raw_cmd->kernel_data == current_req->buffer) {
		/* transfer directly from buffer */
		cont->done(1);
	} else if (CT(COMMAND) == FD_READ) {
		buffer_track = raw_cmd->track;
		buffer_drive = current_drive;
		INFBOUND(buffer_max, nr_sectors + fsector_t);
	}
	cont->redo();
}

/* Compute max