fdc-isr.c

linux-2.6.15.6

	} else if (buff->remaining > 0 && ftape_calc_next_cluster(buff) > 0) {
		/*  still sectors left in current segment, continue
		 *  with this segment
		 */
		if (fdc_setup_read_write(buff, mode) < 0) {
			/* failed, abort operation
			 */
			buff->bytes = buff->ptr - buff->address;
			buff->status = error;
			/* finish this buffer: */
			(void)ftape_next_buffer(ft_queue_head);
			ft_runner_status = aborting;
			fdc_mode         = fdc_idle;
		}
	} else {
		/* current segment completed
		 */
		unsigned int last_segment = buff->segment_id;
		int eot = ((last_segment + 1) % ft_segments_per_track) == 0;
		unsigned int next = buff->next_segment;	/* 0 means stop ! */

		buff->bytes = buff->ptr - buff->address;
		buff->status = done;
		buff = ftape_next_buffer(ft_queue_head);
		if (eot) {
			/*  finished last segment on current track,
			 *  can't continue
			 */
			ft_runner_status = logical_eot;
			fdc_mode         = fdc_idle;
			TRACE_EXIT;
		}
		if (next <= 0) {
			/*  don't continue with next segment
			 */
			TRACE(ft_t_noise, "no %s allowed, stopping tape",
			      (write) ? "write next" : "read ahead");
			pause_tape(0, mode);
			ft_runner_status = idle;  /*  not quite true until
						   *  next irq 
						   */
			TRACE_EXIT;
		}
		/*  continue with next segment
		 */
		if (buff->status != waiting) {
			TRACE(ft_t_noise, "all input buffers %s, pausing tape",
			      (write) ? "empty" : "full");
			pause_tape(0, mode);
			ft_runner_status = idle;  /*  not quite true until
						   *  next irq 
						   */
			TRACE_EXIT;
		}
		if (write && next != buff->segment_id) {
			TRACE(ft_t_noise, 
			      "segments out of order, aborting write");
			ft_runner_status = do_abort;
			fdc_mode         = fdc_idle;
			TRACE_EXIT;
		}
		ftape_setup_new_segment(buff, next, 0);
		if (stop_read_ahead) {
			buff->next_segment = 0;
			stop_read_ahead = 0;
		}
		if (ftape_calc_next_cluster(buff) == 0 ||
		    fdc_setup_read_write(buff, mode) != 0) {
			TRACE(ft_t_err, "couldn't start %s-ahead",
			      write ? "write" : "read");
			ft_runner_status = do_abort;
			fdc_mode         = fdc_idle;
		} else {
			/* keep on going */
			switch (ft_driver_state) {
			case   reading: buff->status = reading;   break;
			case verifying: buff->status = verifying; break;
			case   writing: buff->status = writing;   break;
			case  deleting: buff->status = deleting;  break;
			default:
				TRACE(ft_t_err, 
		      "BUG: ft_driver_state %d should be one out of "
		      "{reading, writing, verifying, deleting}",
				      ft_driver_state);
				buff->status = write ? writing : reading;
				break;
			}
		}
	}
	TRACE_EXIT;
}

static void retry_sector(buffer_struct *buff, 
			 int mode,
			 unsigned int skip)
{
	TRACE_FUN(ft_t_any);

	TRACE(ft_t_noise, "%s error, will retry",
	      (mode == fdc_writing_data || mode == fdc_deleting) ? "write" : "read");
	pause_tape(1, mode);
	ft_runner_status = aborting;
	buff->status     = error;
	buff->skip       = skip;
	TRACE_EXIT;
}

static unsigned int find_resume_point(buffer_struct *buff)
{
	int i = 0;
	SectorMap mask;
	SectorMap map;
	TRACE_FUN(ft_t_any);

	/*  This function is to be called after all variables have been
	 *  updated to point past the failing sector.
	 *  If there are any soft errors before the failing sector,
	 *  find the first soft error and return the sector offset.
	 *  Otherwise find the last hard error.
	 *  Note: there should always be at least one hard or soft error !
	 */
	if (buff->sector_offset < 1 || buff->sector_offset > 32) {
		TRACE(ft_t_bug, "BUG: sector_offset = %d",
		      buff->sector_offset);
		TRACE_EXIT 0;
	}
	if (buff->sector_offset >= 32) { /* C-limitation on shift ! */
		mask = 0xffffffff;
	} else {
		mask = (1 << buff->sector_offset) - 1;
	}
	map = buff->soft_error_map & mask;
	if (map) {
		while ((map & (1 << i)) == 0) {
			++i;
		}
		TRACE(ft_t_noise, "at sector %d", FT_SECTOR(i));
	} else {
		map = buff->hard_error_map & mask;
		i = buff->sector_offset - 1;
		if (map) {
			while ((map & (1 << i)) == 0) {
				--i;
			}
			TRACE(ft_t_noise, "after sector %d", FT_SECTOR(i));
			++i; /* first sector after last hard error */
		} else {
			TRACE(ft_t_bug, "BUG: no soft or hard errors");
		}
	}
	TRACE_EXIT i;
}

/*  check possible dma residue when formatting, update position record in
 *  buffer struct. This is, of course, modelled after determine_progress(), but
 *  we don't need to set up for retries because the format process cannot be
 *  interrupted (except at the end of the tape track).
 */
static int determine_fmt_progress(buffer_struct *buff, error_cause cause)
{
	unsigned int dma_residue;
	TRACE_FUN(ft_t_any);

	/*  Using less preferred order of disable_dma and
	 *  get_dma_residue because this seems to fail on at least one
	 *  system if reversed!
	 */
	dma_residue = get_dma_residue(fdc.dma);
	disable_dma(fdc.dma);
	if (cause != no_error || dma_residue != 0) {
		TRACE(ft_t_info, "DMA residue = 0x%04x", dma_residue);
		fdc_mode = fdc_idle;
		switch(cause) {
		case no_error:
			ft_runner_status = aborting;
			buff->status = idle;
			break;
		case overrun_error:
			/*  got an overrun error on the first byte, must be a
			 *  hardware problem 
			 */
			TRACE(ft_t_bug, 
			      "Unexpected error: failing DMA controller ?");
			ft_runner_status = do_abort;
			buff->status = error;
			break;
		default:
			TRACE(ft_t_noise, "Unexpected error at segment %d",
			      buff->segment_id);
			ft_runner_status = do_abort;
			buff->status = error;
			break;
		}
		TRACE_EXIT -EIO; /* can only retry entire track in format mode
				  */
	}
	/*  Update var's influenced by the DMA operation.
	 */
	buff->ptr             += FT_SECTORS_PER_SEGMENT * 4;
	buff->bytes           -= FT_SECTORS_PER_SEGMENT * 4;
	buff->remaining       -= FT_SECTORS_PER_SEGMENT;
	buff->segment_id ++; /* done with segment */
	TRACE_EXIT 0;
}

/*
 *  Continue formatting, switch buffers if there is no data left in
 *  current buffer. This is, of course, modelled after
 *  continue_xfer(), but we don't need to set up for retries because
 *  the format process cannot be interrupted (except at the end of the
 *  tape track).
 */
static void continue_formatting(buffer_struct *buff)
{
	TRACE_FUN(ft_t_any);

	if (buff->remaining <= 0) { /*  no space left in dma buffer */
		unsigned int next = buff->next_segment; 

		if (next == 0) { /* end of tape track */
			buff->status     = done;
			ft_runner_status = logical_eot;
			fdc_mode         = fdc_idle;
			TRACE(ft_t_noise, "Done formatting track %d",
			      ft_location.track);
			TRACE_EXIT;
		}
		/*
		 *  switch to next buffer!
		 */
		buff->status   = done;
		buff = ftape_next_buffer(ft_queue_head);

		if (buff->status != waiting  || next != buff->segment_id) {
			goto format_setup_error;
		}
	}
	if (fdc_setup_formatting(buff) < 0) {
		goto format_setup_error;
	}
	buff->status = formatting;
	TRACE(ft_t_fdc_dma, "Formatting segment %d on track %d",
	      buff->segment_id, ft_location.track);
	TRACE_EXIT;
 format_setup_error:
	ft_runner_status = do_abort;
	fdc_mode         = fdc_idle;
	buff->status     = error;
	TRACE(ft_t_err, "Error setting up for segment %d on track %d",
	      buff->segment_id, ft_location.track);
	TRACE_EXIT;

}

/*  this handles writing, read id, reading and formatting
 */
static void handle_fdc_busy(buffer_struct *buff)
{
	static int no_data_error_count;
	int retry = 0;
	error_cause cause;
	__u8 in[7];
	int skip;
	fdc_mode_enum fmode = fdc_mode;
	TRACE_FUN(ft_t_any);

	if (fdc_result(in, 7) < 0) { /* better get it fast ! */
		TRACE(ft_t_err, 
		      "Probably fatal error during FDC Result Phase\n"
		      KERN_INFO
		      "drive may hang until (power on) reset :-(");
		/*  what to do next ????
		 */
		TRACE_EXIT;
	}
	cause = decode_irq_cause(fdc_mode, in);
#ifdef TESTING
	{ int i;
	for (i = 0; i < (int)ft_nr_buffers; ++i)
		TRACE(ft_t_any, "buffer[%d] status: %d, segment_id: %d",
		      i, ft_buffer[i]->status, ft_buffer[i]->segment_id);
	}
#endif
	if (fmode == fdc_reading_data && ft_driver_state == verifying) {
		fmode = fdc_verifying;
	}
	switch (fmode) {
	case fdc_verifying:
		if (ft_runner_status == aborting ||
		    ft_runner_status == do_abort) {
			TRACE(ft_t_noise,"aborting %s",fdc_mode_txt(fdc_mode));
			break;
		}
		if (buff->retry > 0) {
			TRACE(ft_t_flow, "this is retry nr %d", buff->retry);
		}
		switch (cause) {
		case no_error:
			no_data_error_count = 0;
			determine_verify_progress(buff, cause, in[5]);
			if (in[2] & 0x40) {
				/*  This should not happen when verifying
				 */
				TRACE(ft_t_warn,
				      "deleted data in segment %d/%d",
				      buff->segment_id,
				      FT_SECTOR(buff->sector_offset - 1));
				buff->remaining = 0; /* abort transfer */
				buff->hard_error_map = EMPTY_SEGMENT;
				skip = 1;
			} else {
				skip = 0;
			}
			continue_xfer(buff, fdc_mode, skip);
			break;
		case no_data_error:
			no_data_error_count ++;
		case overrun_error:
			retry ++;
		case id_am_error:
		case id_crc_error:
		case data_am_error:
		case data_crc_error:
			determine_verify_progress(buff, cause, in[5]); 
			if (cause == no_data_error) {
				if (no_data_error_count >= 2) {
					TRACE(ft_t_warn,
					      "retrying because of successive "
					      "no data errors");
					no_data_error_count = 0;
				} else {
					retry --;
				}
			} else {
				no_data_error_count = 0;
			}
			if (retry) {
				skip = find_resume_point(buff);
			} else {
				skip = buff->sector_offset;
			}
			if (retry && skip < 32) {
				retry_sector(buff, fdc_mode, skip);
			} else {
				continue_xfer(buff, fdc_mode, skip);
			}
			update_history(cause);
			break;
		default:
			/*  Don't know why this could happen 
			 *  but find out.
			 */
			determine_verify_progress(buff, cause, in[5]);
			retry_sector(buff, fdc_mode, 0);
			TRACE(ft_t_err, "Error: unexpected error");
			break;
		}
		break;
	case fdc_reading_data:
#ifdef TESTING
		/* I'm sorry, but: NOBODY ever used this trace
		 * messages for ages. I guess that Bas was the last person
		 * that ever really used this (thank you, between the lines)
		 */
		if (cause == no_error) {
			TRACE(ft_t_flow,"reading segment %d",buff->segment_id);
		} else {
			TRACE(ft_t_noise, "error reading segment %d",
			      buff->segment_id);
			TRACE(ft_t_noise, "\n"
			      KERN_INFO
			     "IRQ:C: 0x%02x, H: 0x%02x, R: 0x%02x, N: 0x%02x\n"
			      KERN_INFO
			      "BUF:C: 0x%02x, H: 0x%02x, R: 0x%02x",
			      in[3], in[4], in[5], in[6],
			      buff->cyl, buff->head, buff->sect);
		}
#endif
		if (ft_runner_status == aborting ||
		    ft_runner_status == do_abort) {
			TRACE(ft_t_noise,"aborting %s",fdc_mode_txt(fdc_mode));
			break;
		}
		if (buff->bad_sector_map == FAKE_SEGMENT) {
			/* This condition occurs when reading a `fake'
			 * sector that's not accessible. Doesn't
			 * really matter as we would have ignored it
			 * anyway !
			 *
			 * Chance is that we're past the next segment
			 * now, so the next operation may fail and
			 * result in a retry.  
			 */
			buff->remaining = 0;	/* skip failing sector */
			/* buff->ptr       = buff->address; */
			/* fake success: */
			continue_xfer(buff, fdc_mode, 1);
			/*  trace calls are expensive: place them AFTER
			 *  the real stuff has been done.
			 *  
			 */
			TRACE(ft_t_noise, "skipping empty segment %d (read), size? %d",
			      buff->segment_id, buff->ptr - buff->address);
			TRACE_EXIT;
		}
		if (buff->retry > 0) {
			TRACE(ft_t_flow, "this is retry nr %d", buff->retry);
		}
		switch (cause) {
		case no_error:
			determine_progress(buff, cause, in[5]);
			if (in[2] & 0x40) {
				/*  Handle deleted data in header segments.
				 *  Skip segment and force read-ahead.
				 */
				TRACE(ft_t_warn,
				      "deleted data in segment %d/%d",
				      buff->segment_id,
				      FT_SECTOR(buff->sector_offset - 1));
				buff->deleted = 1;
				buff->remaining = 0;/*abort transfer */
				buff->soft_error_map |=
						(-1L << buff->sector_offset);
				if (buff->segment_id == 0) {
					/* stop on next segment */
					stop_read_ahead = 1;
				}
				/* force read-ahead: */
				buff->next_segment = 
					buff->segment_id + 1;
				skip = (FT_SECTORS_PER_SEGMENT - 
					buff->sector_offset);
			} else {
				skip = 0;
			}
			continue_xfer(buff, fdc_mode, skip);
			break;
		case no_data_error:
			/* Tape started too far ahead of or behind the
			 * right sector.  This may also happen in the
			 * middle of a segment !
			 *
			 * Handle no-data as soft error. If next
			 * sector fails too, a retry (with needed
			 * reposition) will follow.
			 */
			retry ++;
		case id_am_error:
		case id_crc_error:
		case data_am_error:
		case data_crc_error:
		case overrun_error:
			retry += (buff->soft_error_map != 0 ||
				  buff->hard_error_map != 0);
			determine_progress(buff, cause, in[5]); 
#if 1 || defined(TESTING)
			if (cause == overrun_error) retry ++;
#endif
			if (retry) {
				skip = find_resume_point(buff);
			} else {
				skip = buff->sector_offset;
			}
			/*  Try to resume with next sector on single
			 *  errors (let ecc correct it), but retry on
			 *  no_data (we'll be past the target when we
			 *  get here so we cannot retry) or on
			 *  multiple errors (reduce chance on ecc
			 *  failure).
			 */
			/*  cH: 23/02/97: if the last sector in the 
			 *  segment was a hard error, then there is 
			 *  no sense in a retry. This occasion seldom
			 *  occurs but ... @:巢竊@%&