/*
* Copyright (C) 1993-1995 Bas Laarhoven.
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: /home/bas/distr/ftape-2.03b/RCS/ftape-read.c,v $
$Author: bas $
*
$Revision: 1.30 $
$Date: 1995/05/27 08:54:21 $
$State: Beta $
*
* 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 <asm/segment.h>
#include "tracing.h"
#include "ftape-read.h"
#include "qic117.h"
#include "ftape-io.h"
#include "ftape-ctl.h"
#include "ftape-rw.h"
#include "ftape-write.h"
#include "ftape-eof.h"
#include "ecc.h"
#include "ftape-bsm.h"
/* Global vars.
*/
/* Local vars.
*/
int buf_pos_rd = 0;
int buf_len_rd = 0;
void ftape_zap_read_buffers(void)
{
int i;
for (i = 0; i < NR_BUFFERS; ++i) {
/*
* changed to "fit" with dynamic allocation of tape_buffer. --khp
*/
buffer[i].address = tape_buffer[i];
buffer[i].status = waiting;
buffer[i].bytes = 0;
buffer[i].skip = 0;
buffer[i].retry = 0;
}
buf_len_rd = 0;
buf_pos_rd = 0;
eof_mark = 0;
ftape_state = idle;
}
static unsigned long convert_sector_map(buffer_struct * buff)
{
TRACE_FUN(8, "convert_sector_map");
int i = 0;
unsigned long bad_map = get_bad_sector_entry(buff->segment_id);
unsigned long src_map = buff->soft_error_map | buff->hard_error_map;
unsigned long dst_map = 0;
if (bad_map || src_map) {
TRACEx1(5, "bad_map = 0x%08lx", bad_map);
TRACEx1(5, "src_map = 0x%08lx", 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) {
TRACEx1(5, "dst_map = 0x%08lx", dst_map);
}
TRACE_EXIT;
return dst_map;
}
int correct_and_copy(unsigned int tail, byte * destination)
{
TRACE_FUN(8, "correct_and_copy");
struct memory_segment mseg;
int result;
BAD_SECTOR read_bad;
mseg.read_bad = convert_sector_map(&buffer[tail]);
mseg.marked_bad = 0; /* not used... */
mseg.blocks = buffer[tail].bytes / SECTOR_SIZE;
mseg.data = buffer[tail].address;
/* If there are no data sectors we can skip this segment.
*/
if (mseg.blocks <= 3) {
TRACE(4, "empty segment");
TRACE_EXIT;
return 0;
}
read_bad = mseg.read_bad;
history.crc_errors += count_ones(read_bad);
result = ecc_correct_data(&mseg);
if (read_bad != 0 || mseg.corrected != 0) {
TRACElx(4, "crc error map:", read_bad);
TRACElx(4, "corrected map:", mseg.corrected);
history.corrected += count_ones(mseg.corrected);
}
if (result == ECC_CORRECTED || result == ECC_OK) {
if (result == ECC_CORRECTED) {
TRACEi(3, "ecc corrected segment:", buffer[tail].segment_id);
}
memcpy(destination, mseg.data, (mseg.blocks - 3) * SECTOR_SIZE);
if ((read_bad ^ mseg.corrected) & mseg.corrected) {
/* sectors corrected without crc errors set */
history.crc_failures++;
}
TRACE_EXIT;
return (mseg.blocks - 3) * SECTOR_SIZE;
} else {
TRACEi(1, "ecc failure on segment", buffer[tail].segment_id);
history.ecc_failures++;
TRACE_EXIT;
return -EAGAIN; /* should retry */
}
TRACE_EXIT;
return 0;
}
/* Read given segment into buffer at address.
*/
int read_segment(unsigned segment_id, byte * address, int *eof_mark,
int read_ahead)
{
TRACE_FUN(5, "read_segment");
int read_done = 0;
int result = 0;
int bytes_read = 0;
int retry = 0;
TRACEi(5, "segment_id =", segment_id);
if (ftape_state != reading) {
if (ftape_state == writing) {
ftape_flush_buffers(); /* flush write buffer */
TRACE(5, "calling ftape_abort_operation");
result = ftape_abort_operation();
if (result < 0) {
TRACE(1, "ftape_abort_operation failed");
TRACE_EXIT;
return -EIO;
}
} else {
/* clear remaining read buffers */
ftape_zap_read_buffers();
}
ftape_state = reading;
}
if (segment_id >= segments_per_track * tracks_per_tape) {
TRACE(5, "reading past end of tape");
TRACE_EXIT;
return -ENOSPC;
}
for (;;) {
/* Search all full buffers for the first matching the wanted segment.
* Clear other buffers on the fly.
*/
while (!read_done && buffer[tail].status == done) {
if (buffer[tail].segment_id == segment_id) {
unsigned eof_sector;
unsigned sector_count = 0;
unsigned long bsm = get_bad_sector_entry(segment_id);
int i;
/* If out buffer is already full, return its contents.
*/
if (buffer[tail].deleted) {
TRACEi(5, "found segment in cache :", segment_id);
TRACE_EXIT;
/* 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.
*/
return 0;
}
TRACEi(5, "found segment in cache :", segment_id);
eof_sector = check_for_eof(segment_id);
if (eof_sector > 0) {
TRACEi(5, "end of file mark in sector:", eof_sector);
for (i = 1; i < eof_sector; ++i) {
if ((bsm & 1) == 0) {
++sector_count;
}
bsm >>= 1;
}
*eof_mark = 1;
}
if (eof_sector != 1) { /* not found or gt 1 */
result = correct_and_copy(tail, address);
TRACEi(5, "segment contains (bytes) :", result);
if (result < 0) {
if (result != -EAGAIN) {
TRACE_EXIT;
return result;
}
/* keep read_done == 0, will trigger ftape_abort_operation
* because reading wrong segment.
*/
TRACE(1, "ecc failed, retry");
++retry;
} else {
read_done = 1;
}
} else {
read_done = 1;
}
if (eof_sector > 0) {
bytes_read = sector_count * SECTOR_SIZE;
TRACEi(5, "partial read count:", bytes_read);
} else {
bytes_read = result;
}
} else {
TRACEi(5, "zapping segment in cache :", buffer[tail].segment_id);
}
buffer[tail].status = waiting;
next_buffer(&tail);
}
if (!read_done && buffer[tail].status == reading) {
if (buffer[tail].segment_id == segment_id) {
int result = wait_segment(reading);
if (result < 0) {
if (result == -EINTR) {
TRACE_EXIT;
return result;
}
TRACE(1, "wait_segment failed while reading");
ftape_abort_operation();
}
} else {
/* We're reading the wrong segment, stop runner.
*/
ftape_abort_operation();
}
}
/* if just passed the last segment on a track, wait for BOT or EOT mark.
*/
if (runner_status == logical_eot) {
int status;
result = ftape_ready_wait(timeout.seek, &status);
if (result < 0) {
TRACE(1, "ftape_ready_wait waiting for eot/bot failed");
}
if ((status & (QIC_STATUS_AT_BOT | QIC_STATUS_AT_EOT)) == 0) {
TRACE(1, "eot/bot not reached");
}
runner_status = end_of_tape;
}
/* should runner stop ?
*/
if (runner_status == aborting || runner_status == buffer_overrun ||
runner_status == end_of_tape) {
if (runner_status != end_of_tape &&
!(runner_status == aborting && !tape_running)) {
ftape_dumb_stop();
}
if (runner_status == aborting) {
if (buffer[head].status == reading || buffer[head].status == error) {
if (buffer[head].status == error) {
history.defects += count_ones(buffer[head].hard_error_map);
}
buffer[head].status = waiting;
}
}
runner_status = idle; /* aborted ? */
}
/* If segment to read is empty, do not start runner for it,
* but wait for next read call.
*/
if (get_bad_sector_entry(segment_id) == EMPTY_SEGMENT) {
bytes_read = 0; /* flag empty segment */
read_done = 1;
}
/* Allow escape from this loop on signal !
*/
if (current->signal & _DONT_BLOCK) {
TRACE(2, "interrupted by non-blockable signal");
TRACE_EXIT;
return -EINTR;
}
/* If we got a segment: quit, or else retry up to limit.
*/
if (read_done) {
break;
}
if (retry > RETRIES_ON_ECC_ERROR) {
history.defects++;
TRACE(1, "too many retries on ecc failure");
TRACE_EXIT;
return -ENODATA;
}
/* Now at least one buffer is empty !
* Restart runner & tape if needed.
*/
TRACEx3(8, "head: %d, tail: %d, runner_status: %d",
head, tail, runner_status);
TRACEx2(8, "buffer[].status, [head]: %d, [tail]: %d",
buffer[head].status, buffer[tail].status);
if (buffer[tail].status == waiting) {
setup_new_segment(&buffer[head], segment_id, -1);
if (!read_ahead) {
buffer[head].next_segment = 0; /* disable read-ahead */
}
calc_next_cluster(&buffer[head]);
if (runner_status == idle) {
result = ftape_start_tape(segment_id,
buffer[head].sector_offset);
if (result < 0) {
TRACEx1(1, "Error: segment %d unreachable", segment_id);
TRACE_EXIT;
return result;
}
runner_status = running;
}
buffer[head].status = reading;
setup_fdc_and_dma(&buffer[head], FDC_READ);
}
}
if (read_done) {
TRACE_EXIT;
return bytes_read;
} else {
TRACE(1, "too many retries");
TRACE_EXIT;
return -EIO;
}
}
int read_header_segment(byte * address)
{
TRACE_FUN(5, "read_header_segment");
int i;
int result;
int header_segment = -1;
unsigned int max_floppy_side;
unsigned int max_floppy_track;
unsigned int max_floppy_sector;
int first_failed = 0;
int status;
int new_tape_len;
result = ftape_report_drive_status(&status);
if (result < 0) {
TRACE(1, "error: error_status or report failure");
TRACE_EXIT;
return -EIO;
}
TRACE(5, "reading...");
ftape_last_segment.id = 68; /* will allow us to read the header ! */
/* 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.
*/
used_header_segment = -1;
result = 0;
for (header_segment = 0;
header_segment < ftape_last_segment.id && result == 0;
++header_segment) {
/* Set no read-ahead, the isr will force read-ahead whenever
* it encounters deleted data !
*/
result = read_segment(header_segment, address, &status, 0);
if (result < 0 && !first_failed) {
TRACE(1, "header segment damaged, trying backup");
first_failed = 1;
result = 0; /* force read of next (backup) segment */
}
}
if (result < 0 || header_segment >= ftape_last_segment.id) {
TRACE(1, "no readable header segment found");
TRACE_EXIT;
return -EIO;
}
result = ftape_abort_operation();
if (result < 0) {
TRACE(1, "ftape_abort_operation failed");
TRACE_EXIT;
return -EIO;
}
if (GET4(address, 0) != 0xaa55aa55) {
TRACE(1, "wrong signature in header segment");
TRACE_EXIT;
return -EIO;
}
header_segment_1 = GET2(address, 6);
header_segment_2 = GET2(address, 8);
TRACEx2(2, "header segments are %d and %d",
header_segment_1, header_segment_2);
used_header_segment = (first_failed) ? header_segment_2 : header_segment_1;
/* 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) /
* segments_per_head
* max-floppy-track segments_per_head /
* segments_per_cylinder - 1
* max-floppy-sector segments_per_cylinder *
* SECTORS_PER_SEGMENT
*/
format_code = (format_type) * (address + 4);
segments_per_track = GET2(address, 24);
tracks_per_tape = *(address + 26);
max_floppy_side = *(address + 27);
max_floppy_track = *(address + 28);
max_floppy_sector = *(address + 29);
TRACEx6(4, "(fmt/spt/tpc/fhm/ftm/fsm) = %d/%d/%d/%d/%d/%d",
format_code, segments_per_track, tracks_per_tape,
max_floppy_side, max_floppy_track, max_floppy_sector);
new_tape_len = tape_len;
switch (format_code) {
case fmt_425ft:
new_tape_len = 425;
break;
case fmt_normal:
if (tape_len == 0) { /* otherwise 307 ft */
new_tape_len = 205;
}
break;
case fmt_1100ft:
new_tape_len = 1100;
break;
case fmt_wide:{
int segments_per_1000_inch = 1; /* non-zero default for switch */
switch (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 * segments_per_track +
(segments_per_1000_inch - 1)) / segments_per_1000_inch;
break;
}
default:
TRACE(1, "unknown tape format, please report !");
TRACE_EXIT;
return -EIO;
}
if (new_tape_len != tape_len) {
tape_len = new_tape_len;
TRACEx1(1, "calculated tape length is %d ft", tape_len);
ftape_calc_timeouts();
}
if (segments_per_track == 0 && 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.
*/
segments_per_track = 68;
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 (segments_per_track == 150 &&
tracks_per_tape == 28 &&
max_floppy_side == 7 &&
max_floppy_track == 149 &&
max_floppy_sector == 128) {
TRACE(-1, "the famous CONNER bug: max_floppy_side off by one !");
max_floppy_side = 6;
}
/* This test will compensate for the wrong parameter on tapes
* formatted by Colorado Windows software.
*/
if (segments_per_track == 150 &&
tracks_per_tape == 28 &&
max_floppy_side == 6 &&
max_floppy_track == 150 &&
max_floppy_sector == 128) {
TRACE(-1, "the famous Colorado bug: max_floppy_track off by one !");
max_floppy_track = 149;
}
segments_per_head = ((max_floppy_sector / SECTORS_PER_SEGMENT) *
(max_floppy_track + 1));
/*
* Verify drive_configuration with tape parameters
*/
if (segments_per_head == 0 || segments_per_cylinder == 0 ||
((segments_per_track * tracks_per_tape - 1) / segments_per_head
!= max_floppy_side) ||
(segments_per_head / segments_per_cylinder - 1 != max_floppy_track) ||
(segments_per_cylinder * SECTORS_PER_SEGMENT != max_floppy_sector)
#ifdef TESTING
|| (format_code == 4 && (max_floppy_track != 254 || max_floppy_sector != 128))
#endif
) {
TRACE(1, "Tape parameters inconsistency, please report");
TRACE_EXIT;
return -EIO;
}
first_data_segment = GET2(address, 10); /* first data segment */
TRACEi(4, "first data segment:", first_data_segment);
extract_bad_sector_map(address);
/* Find the highest segment id that allows still one full
* deblock_buffer to be written to tape.
*/
ftape_last_segment.size = 0;
for (i = segments_per_track * tracks_per_tape - 1; i >= 0; --i) {
int space = SECTORS_PER_SEGMENT - 3 - count_ones(get_bad_sector_entry(i));
if (space > 0) {
ftape_last_segment.size += space; /* sectors free */
ftape_last_segment.free = (ftape_last_segment.size -
sizeof(deblock_buffer) / SECTOR_SIZE);
if (ftape_last_segment.free >= 0) {
ftape_last_segment.id = i;
TRACEx2(4, "`last' segment is %d, %d Kb",
ftape_last_segment.id, ftape_last_segment.size);
break;
}
}
}
/* Copy the failed sector log into our local buffer.
*/
if (!ftape_validate_label(&deblock_buffer[30])) {
TRACE(-1, "This tape has no `Linux raw format' label,\n"
"***** Use `mt' to erase this tape if you want to use file marks !");
} else {
extract_file_marks(address);
}
ftape_reset_position();
TRACE_EXIT;
return 0;
}
int _ftape_read(char *buff, int req_len)
{
TRACE_FUN(5, "_ftape_read");
int result = 0;
int cnt;
int to_do = req_len;
static int remaining;
int bytes_read = 0;
if (ftape_offline || !formatted || no_tape) {
TRACEx3(-1, "offline = %d, formatted = %d, no_tape = %d",
ftape_offline, formatted, no_tape);
result = -EIO;
} else {
history.used |= 1;
if (first_data_segment == -1) {
result = read_header_segment(deblock_buffer);
}
}
if (result < 0) {
TRACE_EXIT;
return result;
}
/* As GNU tar doesn't accept partial read counts when the multiple
* volume flag is set, we make sure to return the requested amount
* of data. Except, of course, at the end of the tape or file mark.
*/
while (to_do > 0) { /* don't return with a partial count ! */
/* If we're reading the `last' segment(s) on tape, make sure we don't
* get more than 29 Kb from it (As it only contains this much).
* This works only for sequential access, so random access should
* stay away from this `last' segment.
* Note: ftape_seg_pos points to the next segment that will be
* read, so it's one too high here!
*/
if (!eof_mark && ftape_seg_pos - 1 >= ftape_last_segment.id) {
TRACEi(5, "remaining of last segment:", remaining);
if (to_do > remaining) {
to_do = remaining; /* fake a smaller request */
TRACE(5, "clipped request to remaining");
}
}
while (!eof_mark && buf_len_rd == 0) {
/* When starting to read the `last' segment, set remaining
*/
if (ftape_seg_pos == ftape_last_segment.id) {
remaining = sizeof(deblock_buffer);
TRACEi(5, "remaining set to:", remaining);
}
result = read_segment(ftape_seg_pos, deblock_buffer, &eof_mark, 1);
if (result < 0) {
if (result == -ENODATA) {
/* Unable to recover tape data, return error and skip bad spot.
*/
++ftape_seg_pos;
}
TRACEx1(4, "read_segment result: %d", result);
TRACE_EXIT;
return result;
}
/* Allow escape from this loop on signal !
*/
if (current->signal & _DONT_BLOCK) {
TRACE(2, "interrupted by non-blockable signal");
TRACE_EXIT;
return -EINTR;
}
buf_pos_rd = 0;
buf_len_rd = result;
++ftape_seg_pos;
}
/* Take as much as we can use
*/
cnt = (buf_len_rd < to_do) ? buf_len_rd : to_do;
TRACEi(7, "nr bytes just read:", cnt);
if (cnt > 0) {
result = verify_area(VERIFY_WRITE, buff, cnt);
if (result) {
TRACEx1(1, "verify_area failed, exitcode = %d", result);
TRACE_EXIT;
return -EIO;
}
memcpy_tofs(buff, deblock_buffer + buf_pos_rd, cnt);
buff += cnt;
to_do -= cnt; /* what's left from req_len */
remaining -= cnt; /* what remains on this tape */
bytes_read += cnt; /* what we got so far */
buf_pos_rd += cnt; /* index in buffer */
buf_len_rd -= cnt; /* remaining bytes in buffer */
}
if (eof_mark && buf_len_rd == 0) { /* nothing left */
TRACE(5, "partial count because of eof mark");
if (bytes_read == 0) {
eof_mark = 0; /* no need for mark next read */
}
break;
}
}
TRACE_EXIT;
return bytes_read;
}
