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linux/drivers/char/ftape/lowlevel/ftape-read.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2 
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

622 lines
18 KiB
C
Raw Blame History

/*
* 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 <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
) {
char segperheadz = ftape_segments_per_head ? ' ' : '?';
char segpercylz = ftape_segments_per_cylinder ? ' ' : '?';
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%c/%d%c/%d",
ft_format_code,
ft_segments_per_track,
ft_tracks_per_tape,
ftape_segments_per_head ?
((ft_segments_per_track * ft_tracks_per_tape -1) /
ftape_segments_per_head ) :
(ft_segments_per_track * ft_tracks_per_tape -1),
segperheadz,
ftape_segments_per_cylinder ?
(ftape_segments_per_head /
ftape_segments_per_cylinder - 1 ) :
ftape_segments_per_head - 1,
segpercylz,
(ftape_segments_per_cylinder * FT_SECTORS_PER_SEGMENT));
TRACE_EXIT -EIO;
}
ftape_extract_bad_sector_map(address);
TRACE_EXIT 0;
}
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