patch-2.1.66 linux/drivers/char/ftape/lowlevel/ftape-read.c

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diff -u --recursive --new-file v2.1.65/linux/drivers/char/ftape/lowlevel/ftape-read.c linux/drivers/char/ftape/lowlevel/ftape-read.c
@@ -0,0 +1,614 @@
+/*
+ *      Copyright (C) 1993-1996 Bas Laarhoven,
+ *                (C) 1996-1997 Claus-Justus Heine.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; see the file COPYING.  If not, write to
+ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ *
+ * $Source: /homes/cvs/ftape-stacked/ftape/lowlevel/ftape-read.c,v $
+ * $Revision: 1.6 $
+ * $Date: 1997/10/21 14:39:22 $
+ *
+ *      This file contains the reading code
+ *      for the QIC-117 floppy-tape driver for Linux.
+ *
+ */
+
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <asm/segment.h>
+
+#include <linux/ftape.h>
+#include <linux/qic117.h>
+#include "../lowlevel/ftape-tracing.h"
+#include "../lowlevel/ftape-read.h"
+#include "../lowlevel/ftape-io.h"
+#include "../lowlevel/ftape-ctl.h"
+#include "../lowlevel/ftape-rw.h"
+#include "../lowlevel/ftape-write.h"
+#include "../lowlevel/ftape-ecc.h"
+#include "../lowlevel/ftape-bsm.h"
+
+/*      Global vars.
+ */
+
+/*      Local vars.
+ */
+
+void ftape_zap_read_buffers(void)
+{
+	int i;
+
+	for (i = 0; i < ft_nr_buffers; ++i) {
+/*  changed to "fit" with dynamic allocation of tape_buffer. --khp  */
+		ft_buffer[i]->status = waiting;
+		ft_buffer[i]->bytes = 0;
+		ft_buffer[i]->skip = 0;
+		ft_buffer[i]->retry = 0;
+	}
+/*	ftape_reset_buffer(); */
+}
+
+static SectorMap convert_sector_map(buffer_struct * buff)
+{
+	int i = 0;
+	SectorMap bad_map = ftape_get_bad_sector_entry(buff->segment_id);
+	SectorMap src_map = buff->soft_error_map | buff->hard_error_map;
+	SectorMap dst_map = 0;
+	TRACE_FUN(ft_t_any);
+
+	if (bad_map || src_map) {
+		TRACE(ft_t_flow, "bad_map = 0x%08lx", (long) bad_map);
+		TRACE(ft_t_flow, "src_map = 0x%08lx", (long) src_map);
+	}
+	while (bad_map) {
+		while ((bad_map & 1) == 0) {
+			if (src_map & 1) {
+				dst_map |= (1 << i);
+			}
+			src_map >>= 1;
+			bad_map >>= 1;
+			++i;
+		}
+		/* (bad_map & 1) == 1 */
+		src_map >>= 1;
+		bad_map >>= 1;
+	}
+	if (src_map) {
+		dst_map |= (src_map << i);
+	}
+	if (dst_map) {
+		TRACE(ft_t_flow, "dst_map = 0x%08lx", (long) dst_map);
+	}
+	TRACE_EXIT dst_map;
+}
+
+static int correct_and_copy_fraction(buffer_struct *buff, __u8 * destination,
+				     int start, int size)
+{
+	struct memory_segment mseg;
+	int result;
+	SectorMap read_bad;
+	TRACE_FUN(ft_t_any);
+
+	mseg.read_bad = convert_sector_map(buff);
+	mseg.marked_bad = 0;	/* not used... */
+	mseg.blocks = buff->bytes / FT_SECTOR_SIZE;
+	mseg.data = buff->address;
+	/*    If there are no data sectors we can skip this segment.
+	 */
+	if (mseg.blocks <= 3) {
+		TRACE_ABORT(0, ft_t_noise, "empty segment");
+	}
+	read_bad = mseg.read_bad;
+	ft_history.crc_errors += count_ones(read_bad);
+	result = ftape_ecc_correct_data(&mseg);
+	if (read_bad != 0 || mseg.corrected != 0) {
+		TRACE(ft_t_noise, "crc error map: 0x%08lx", (unsigned long)read_bad);
+		TRACE(ft_t_noise, "corrected map: 0x%08lx", (unsigned long)mseg.corrected);
+		ft_history.corrected += count_ones(mseg.corrected);
+	}
+	if (result == ECC_CORRECTED || result == ECC_OK) {
+		if (result == ECC_CORRECTED) {
+			TRACE(ft_t_info, "ecc corrected segment: %d", buff->segment_id);
+		}
+		if(start < 0) {
+			start= 0;
+		}
+		if((start+size) > ((mseg.blocks - 3) * FT_SECTOR_SIZE)) {
+			size = (mseg.blocks - 3) * FT_SECTOR_SIZE  - start;
+		} 
+		if (size < 0) {
+			size= 0;
+		}
+		if(size > 0) {
+			memcpy(destination + start, mseg.data + start, size);
+		}
+		if ((read_bad ^ mseg.corrected) & mseg.corrected) {
+			/* sectors corrected without crc errors set */
+			ft_history.crc_failures++;
+		}
+		TRACE_EXIT size; /* (mseg.blocks - 3) * FT_SECTOR_SIZE; */
+	} else {
+		ft_history.ecc_failures++;
+		TRACE_ABORT(-EAGAIN,
+			    ft_t_err, "ecc failure on segment %d",
+			    buff->segment_id);
+	}
+	TRACE_EXIT 0;
+}
+
+/*      Read given segment into buffer at address.
+ */
+int ftape_read_segment_fraction(const int segment_id,
+				void  *address, 
+				const ft_read_mode_t read_mode,
+				const int start,
+				const int size)
+{
+	int result = 0;
+	int retry  = 0;
+	int bytes_read = 0;
+	int read_done  = 0;
+	TRACE_FUN(ft_t_flow);
+
+	ft_history.used |= 1;
+	TRACE(ft_t_data_flow, "segment_id = %d", segment_id);
+	if (ft_driver_state != reading) {
+		TRACE(ft_t_noise, "calling ftape_abort_operation");
+		TRACE_CATCH(ftape_abort_operation(),);
+		ftape_set_state(reading);
+	}
+	for(;;) {
+		buffer_struct *tail;
+		/*  Allow escape from this loop on signal !
+		 */
+		FT_SIGNAL_EXIT(_DONT_BLOCK);
+		/*  Search all full buffers for the first matching the
+		 *  wanted segment.  Clear other buffers on the fly.
+		 */
+		tail = ftape_get_buffer(ft_queue_tail);
+		while (!read_done && tail->status == done) {
+			/*  Allow escape from this loop on signal !
+			 */
+			FT_SIGNAL_EXIT(_DONT_BLOCK);
+			if (tail->segment_id == segment_id) {
+				/*  If out buffer is already full,
+				 *  return its contents.  
+				 */
+				TRACE(ft_t_flow, "found segment in cache: %d",
+				      segment_id);
+				if (tail->deleted) {
+					/*  Return a value that
+					 *  read_header_segment
+					 *  understands.  As this
+					 *  should only occur when
+					 *  searching for the header
+					 *  segments it shouldn't be
+					 *  misinterpreted elsewhere.
+					 */
+					TRACE_EXIT 0;
+				}
+				result = correct_and_copy_fraction(
+					tail,
+					address,
+					start,
+					size);
+				TRACE(ft_t_flow, "segment contains (bytes): %d",
+				      result);
+				if (result < 0) {
+					if (result != -EAGAIN) {
+						TRACE_EXIT result;
+					}
+					/* keep read_done == 0, will
+					 * trigger
+					 * ftape_abort_operation
+					 * because reading wrong
+					 * segment.
+					 */
+					TRACE(ft_t_err, "ecc failed, retry");
+					++retry;
+				} else {
+					read_done = 1;
+					bytes_read = result;
+				}
+			} else {
+				TRACE(ft_t_flow,"zapping segment in cache: %d",
+				      tail->segment_id);
+			}
+			tail->status = waiting;
+			tail = ftape_next_buffer(ft_queue_tail);
+		}
+		if (!read_done && tail->status == reading) {
+			if (tail->segment_id == segment_id) {
+				switch(ftape_wait_segment(reading)) {
+				case 0:
+					break;
+				case -EINTR:
+					TRACE_ABORT(-EINTR, ft_t_warn,
+						    "interrupted by "
+						    "non-blockable signal");
+					break;
+				default:
+					TRACE(ft_t_noise,
+					      "wait_segment failed");
+					ftape_abort_operation();
+					ftape_set_state(reading);
+					break;
+				}
+			} else {
+				/*  We're reading the wrong segment,
+				 *  stop runner.
+				 */
+				TRACE(ft_t_noise, "reading wrong segment");
+				ftape_abort_operation();
+				ftape_set_state(reading);
+			}
+		}
+		/*    should runner stop ?
+		 */
+		if (ft_runner_status == aborting) {
+			buffer_struct *head = ftape_get_buffer(ft_queue_head);
+			switch(head->status) {
+			case error:
+				ft_history.defects += 
+					count_ones(head->hard_error_map);
+			case reading:
+				head->status = waiting;
+				break;
+			default:
+				break;
+			}
+			TRACE_CATCH(ftape_dumb_stop(),);
+		} else {
+			/*  If just passed last segment on tape: wait
+			 *  for BOT or EOT mark. Sets ft_runner_status to
+			 *  idle if at lEOT and successful 
+			 */
+			TRACE_CATCH(ftape_handle_logical_eot(),);
+		}
+		/*    If we got a segment: quit, or else retry up to limit.
+		 *
+		 *    If segment to read is empty, do not start runner for it,
+		 *    but wait for next read call.
+		 */
+		if (read_done ||
+		    ftape_get_bad_sector_entry(segment_id) == EMPTY_SEGMENT ) {
+			/* bytes_read = 0;  should still be zero */
+			TRACE_EXIT bytes_read;
+
+		}
+		if (retry > FT_RETRIES_ON_ECC_ERROR) {
+			ft_history.defects++;
+			TRACE_ABORT(-ENODATA, ft_t_err,
+				    "too many retries on ecc failure");
+		}
+		/*    Now at least one buffer is empty !
+		 *    Restart runner & tape if needed.
+		 */
+		TRACE(ft_t_any, "head: %d, tail: %d, ft_runner_status: %d",
+		      ftape_buffer_id(ft_queue_head),
+		      ftape_buffer_id(ft_queue_tail),
+		      ft_runner_status);
+		TRACE(ft_t_any, "buffer[].status, [head]: %d, [tail]: %d",
+		      ftape_get_buffer(ft_queue_head)->status,
+		      ftape_get_buffer(ft_queue_tail)->status);
+		tail = ftape_get_buffer(ft_queue_tail);
+		if (tail->status == waiting) {
+			buffer_struct *head = ftape_get_buffer(ft_queue_head);
+
+			ftape_setup_new_segment(head, segment_id, -1);
+			if (read_mode == FT_RD_SINGLE) {
+				/* disable read-ahead */
+				head->next_segment = 0;
+			}
+			ftape_calc_next_cluster(head);
+			if (ft_runner_status == idle) {
+				result = ftape_start_tape(segment_id,
+							  head->sector_offset);
+				if (result < 0) {
+					TRACE_ABORT(result, ft_t_err, "Error: "
+						    "segment %d unreachable",
+						    segment_id);
+				}
+			}
+			head->status = reading;
+			fdc_setup_read_write(head, FDC_READ);
+		}
+	}
+	/* not reached */
+	TRACE_EXIT -EIO;
+}
+
+int ftape_read_header_segment(__u8 *address)
+{
+	int result;
+	int header_segment;
+	int first_failed = 0;
+	int status;
+	TRACE_FUN(ft_t_flow);
+
+	ft_used_header_segment = -1;
+	TRACE_CATCH(ftape_report_drive_status(&status),);
+	TRACE(ft_t_flow, "reading...");
+	/*  We're looking for the first header segment.
+	 *  A header segment cannot contain bad sectors, therefor at the
+	 *  tape start, segments with bad sectors are (according to QIC-40/80)
+	 *  written with deleted data marks and must be skipped.
+	 */
+	memset(address, '\0', (FT_SECTORS_PER_SEGMENT - 3) * FT_SECTOR_SIZE); 
+	result = 0;
+#define HEADER_SEGMENT_BOUNDARY 68  /* why not 42? */
+	for (header_segment = 0;
+	     header_segment < HEADER_SEGMENT_BOUNDARY && result == 0;
+	     ++header_segment) {
+		/*  Set no read-ahead, the isr will force read-ahead whenever
+		 *  it encounters deleted data !
+		 */
+		result = ftape_read_segment(header_segment,
+					    address,
+					    FT_RD_SINGLE);
+		if (result < 0 && !first_failed) {
+			TRACE(ft_t_err, "header segment damaged, trying backup");
+			first_failed = 1;
+			result = 0;	/* force read of next (backup) segment */
+		}
+	}
+	if (result < 0 || header_segment >= HEADER_SEGMENT_BOUNDARY) {
+		TRACE_ABORT(-EIO, ft_t_err,
+			    "no readable header segment found");
+	}
+	TRACE_CATCH(ftape_abort_operation(),);
+	ft_used_header_segment = header_segment;
+	result = ftape_decode_header_segment(address);
+ 	TRACE_EXIT result;
+}
+
+int ftape_decode_header_segment(__u8 *address)
+{
+	unsigned int max_floppy_side;
+	unsigned int max_floppy_track;
+	unsigned int max_floppy_sector;
+	unsigned int new_tape_len;
+	TRACE_FUN(ft_t_flow);
+
+	if (GET4(address, FT_SIGNATURE) == FT_D2G_MAGIC) {
+		/* Ditto 2GB header segment. They encrypt the bad sector map.
+		 * We decrypt it and store them in normal format.
+		 * I hope this is correct.
+		 */
+		int i;
+		TRACE(ft_t_warn,
+		      "Found Ditto 2GB tape, "
+		      "trying to decrypt bad sector map");
+		for (i=256; i < 29 * FT_SECTOR_SIZE; i++) {
+			address[i] = ~(address[i] - (i&0xff));
+		}
+		PUT4(address, 0,FT_HSEG_MAGIC);
+	} else if (GET4(address, FT_SIGNATURE) != FT_HSEG_MAGIC) {
+		TRACE_ABORT(-EIO, ft_t_err,
+			    "wrong signature in header segment");
+	}
+	ft_format_code = (ft_format_type) address[FT_FMT_CODE];
+	if (ft_format_code != fmt_big) {
+		ft_header_segment_1   = GET2(address, FT_HSEG_1);
+		ft_header_segment_2   = GET2(address, FT_HSEG_2);
+		ft_first_data_segment = GET2(address, FT_FRST_SEG);
+		ft_last_data_segment  = GET2(address, FT_LAST_SEG);
+	} else {
+		ft_header_segment_1   = GET4(address, FT_6_HSEG_1);
+		ft_header_segment_2   = GET4(address, FT_6_HSEG_2);
+		ft_first_data_segment = GET4(address, FT_6_FRST_SEG);
+		ft_last_data_segment  = GET4(address, FT_6_LAST_SEG);
+	}
+	TRACE(ft_t_noise, "first data segment: %d", ft_first_data_segment);
+	TRACE(ft_t_noise, "last  data segment: %d", ft_last_data_segment);
+	TRACE(ft_t_noise, "header segments are %d and %d",
+	      ft_header_segment_1, ft_header_segment_2);
+
+	/*    Verify tape parameters...
+	 *    QIC-40/80 spec:                 tape_parameters:
+	 *
+	 *    segments-per-track              segments_per_track
+	 *    tracks-per-cartridge            tracks_per_tape
+	 *    max-floppy-side                 (segments_per_track *
+	 *                                    tracks_per_tape - 1) /
+	 *                                    ftape_segments_per_head
+	 *    max-floppy-track                ftape_segments_per_head /
+	 *                                    ftape_segments_per_cylinder - 1
+	 *    max-floppy-sector               ftape_segments_per_cylinder *
+	 *                                    FT_SECTORS_PER_SEGMENT
+	 */
+	ft_segments_per_track = GET2(address, FT_SPT);
+	ft_tracks_per_tape    = address[FT_TPC];
+	max_floppy_side       = address[FT_FHM];
+	max_floppy_track      = address[FT_FTM];
+	max_floppy_sector     = address[FT_FSM];
+	TRACE(ft_t_noise, "(fmt/spt/tpc/fhm/ftm/fsm) = %d/%d/%d/%d/%d/%d",
+	      ft_format_code, ft_segments_per_track, ft_tracks_per_tape,
+	      max_floppy_side, max_floppy_track, max_floppy_sector);
+	new_tape_len = ftape_tape_len;
+	switch (ft_format_code) {
+	case fmt_425ft:
+		new_tape_len = 425;
+		break;
+	case fmt_normal:
+		if (ftape_tape_len == 0) {	/* otherwise 307 ft */
+			new_tape_len = 205;
+		}
+		break;
+	case fmt_1100ft:
+		new_tape_len = 1100;
+		break;
+	case fmt_var:{
+			int segments_per_1000_inch = 1;		/* non-zero default for switch */
+			switch (ft_qic_std) {
+			case QIC_TAPE_QIC40:
+				segments_per_1000_inch = 332;
+				break;
+			case QIC_TAPE_QIC80:
+				segments_per_1000_inch = 488;
+				break;
+			case QIC_TAPE_QIC3010:
+				segments_per_1000_inch = 730;
+				break;
+			case QIC_TAPE_QIC3020:
+				segments_per_1000_inch = 1430;
+				break;
+			}
+			new_tape_len = (1000 * ft_segments_per_track +
+					(segments_per_1000_inch - 1)) / segments_per_1000_inch;
+			break;
+		}
+	case fmt_big:{
+			int segments_per_1000_inch = 1;		/* non-zero default for switch */
+			switch (ft_qic_std) {
+			case QIC_TAPE_QIC40:
+				segments_per_1000_inch = 332;
+				break;
+			case QIC_TAPE_QIC80:
+				segments_per_1000_inch = 488;
+				break;
+			case QIC_TAPE_QIC3010:
+				segments_per_1000_inch = 730;
+				break;
+			case QIC_TAPE_QIC3020:
+				segments_per_1000_inch = 1430;
+				break;
+			default:
+				TRACE_ABORT(-EIO, ft_t_bug,
+			"%x QIC-standard with fmt-code %d, please report",
+					    ft_qic_std, ft_format_code);
+			}
+			new_tape_len = ((1000 * ft_segments_per_track +
+					 (segments_per_1000_inch - 1)) / 
+					segments_per_1000_inch);
+			break;
+		}
+	default:
+		TRACE_ABORT(-EIO, ft_t_err,
+			    "unknown tape format, please report !");
+	}
+	if (new_tape_len != ftape_tape_len) {
+		ftape_tape_len = new_tape_len;
+		TRACE(ft_t_info, "calculated tape length is %d ft",
+		      ftape_tape_len);
+		ftape_calc_timeouts(ft_qic_std, ft_data_rate, ftape_tape_len);
+	}
+	if (ft_segments_per_track == 0 && ft_tracks_per_tape == 0 &&
+	    max_floppy_side == 0 && max_floppy_track == 0 &&
+	    max_floppy_sector == 0) {
+		/*  QIC-40 Rev E and earlier has no values in the header.
+		 */
+		ft_segments_per_track = 68;
+		ft_tracks_per_tape = 20;
+		max_floppy_side = 1;
+		max_floppy_track = 169;
+		max_floppy_sector = 128;
+	}
+	/*  This test will compensate for the wrong parameter on tapes
+	 *  formatted by Conner software.
+	 */
+	if (ft_segments_per_track == 150 &&
+	    ft_tracks_per_tape == 28 &&
+	    max_floppy_side == 7 &&
+	    max_floppy_track == 149 &&
+	    max_floppy_sector == 128) {
+TRACE(ft_t_info, "the famous CONNER bug: max_floppy_side off by one !");
+		max_floppy_side = 6;
+	}
+	/*  These tests will compensate for the wrong parameter on tapes
+	 *  formatted by ComByte Windows software.
+	 *
+	 *  First, for 205 foot tapes
+	 */
+	if (ft_segments_per_track == 100 &&
+	    ft_tracks_per_tape == 28 &&
+	    max_floppy_side == 9 &&
+	    max_floppy_track == 149 &&
+	    max_floppy_sector == 128) {
+TRACE(ft_t_info, "the ComByte bug: max_floppy_side incorrect!");
+		max_floppy_side = 4;
+	}
+	/* Next, for 307 foot tapes. */
+	if (ft_segments_per_track == 150 &&
+	    ft_tracks_per_tape == 28 &&
+	    max_floppy_side == 9 &&
+	    max_floppy_track == 149 &&
+	    max_floppy_sector == 128) {
+TRACE(ft_t_info, "the ComByte bug: max_floppy_side incorrect!");
+		max_floppy_side = 6;
+	}
+	/*  This test will compensate for the wrong parameter on tapes
+	 *  formatted by Colorado Windows software.
+	 */
+	if (ft_segments_per_track == 150 &&
+	    ft_tracks_per_tape == 28 &&
+	    max_floppy_side == 6 &&
+	    max_floppy_track == 150 &&
+	    max_floppy_sector == 128) {
+TRACE(ft_t_info, "the famous Colorado bug: max_floppy_track off by one !");
+		max_floppy_track = 149;
+	}
+	ftape_segments_per_head = ((max_floppy_sector/FT_SECTORS_PER_SEGMENT) *
+				   (max_floppy_track + 1));
+	/*  This test will compensate for some bug reported by Dima
+	 *  Brodsky.  Seems to be a Colorado bug, either. (freebee
+	 *  Imation tape shipped together with Colorado T3000
+	 */
+	if ((ft_format_code == fmt_var || ft_format_code == fmt_big) &&
+	    ft_tracks_per_tape == 50 &&
+	    max_floppy_side == 54 &&
+	    max_floppy_track == 255 &&
+	    max_floppy_sector == 128) {
+TRACE(ft_t_info, "the famous ??? bug: max_floppy_track off by one !");
+		max_floppy_track = 254;
+	}
+	/*
+	 *    Verify drive_configuration with tape parameters
+	 */
+	if (ftape_segments_per_head == 0 || ftape_segments_per_cylinder == 0 ||
+	  ((ft_segments_per_track * ft_tracks_per_tape - 1) / ftape_segments_per_head
+	   != max_floppy_side) ||
+	    (ftape_segments_per_head / ftape_segments_per_cylinder - 1 != max_floppy_track) ||
+	(ftape_segments_per_cylinder * FT_SECTORS_PER_SEGMENT != max_floppy_sector)
+#ifdef TESTING
+	    || ((ft_format_code == fmt_var || ft_format_code == fmt_big) && 
+		(max_floppy_track != 254 || max_floppy_sector != 128))
+#endif
+	   ) {
+		TRACE(ft_t_err,"Tape parameters inconsistency, please report");
+		TRACE(ft_t_err, "reported = %d/%d/%d/%d/%d/%d",
+		      ft_format_code,
+		      ft_segments_per_track,
+		      ft_tracks_per_tape,
+		      max_floppy_side,
+		      max_floppy_track,
+		      max_floppy_sector);
+		TRACE(ft_t_err, "required = %d/%d/%d/%d/%d/%d",
+		      ft_format_code,
+		      ft_segments_per_track,
+		      ft_tracks_per_tape,
+		      ((ft_segments_per_track * ft_tracks_per_tape -1) / 
+		       ftape_segments_per_head ),
+		      (ftape_segments_per_head / 
+		       ftape_segments_per_cylinder - 1 ),
+		      (ftape_segments_per_cylinder * FT_SECTORS_PER_SEGMENT));
+		TRACE_EXIT -EIO;
+	}
+	ftape_extract_bad_sector_map(address);
+ 	TRACE_EXIT 0;
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen, slshen@lbl.gov