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-rw-r--r--drivers/char/ftape/lowlevel/ftape-rw.c1092
1 files changed, 0 insertions, 1092 deletions
diff --git a/drivers/char/ftape/lowlevel/ftape-rw.c b/drivers/char/ftape/lowlevel/ftape-rw.c
deleted file mode 100644
index c0d6dc2cbfd..00000000000
--- a/drivers/char/ftape/lowlevel/ftape-rw.c
+++ /dev/null
@@ -1,1092 +0,0 @@
-/*
- * 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-rw.c,v $
- * $Revision: 1.7 $
- * $Date: 1997/10/28 14:26:49 $
- *
- * This file contains some common code for the segment read and
- * segment write routines for the QIC-117 floppy-tape driver for
- * Linux.
- */
-
-#include <linux/string.h>
-#include <linux/errno.h>
-
-#include <linux/ftape.h>
-#include <linux/qic117.h>
-#include "../lowlevel/ftape-tracing.h"
-#include "../lowlevel/ftape-rw.h"
-#include "../lowlevel/fdc-io.h"
-#include "../lowlevel/ftape-init.h"
-#include "../lowlevel/ftape-io.h"
-#include "../lowlevel/ftape-ctl.h"
-#include "../lowlevel/ftape-read.h"
-#include "../lowlevel/ftape-ecc.h"
-#include "../lowlevel/ftape-bsm.h"
-
-/* Global vars.
- */
-int ft_nr_buffers;
-buffer_struct *ft_buffer[FT_MAX_NR_BUFFERS];
-static volatile int ft_head;
-static volatile int ft_tail; /* not volatile but need same type as head */
-int fdc_setup_error;
-location_record ft_location = {-1, 0};
-volatile int ftape_tape_running;
-
-/* Local vars.
- */
-static int overrun_count_offset;
-static int inhibit_correction;
-
-/* maxmimal allowed overshoot when fast seeking
- */
-#define OVERSHOOT_LIMIT 10
-
-/* Increment cyclic buffer nr.
- */
-buffer_struct *ftape_next_buffer(ft_buffer_queue_t pos)
-{
- switch (pos) {
- case ft_queue_head:
- if (++ft_head >= ft_nr_buffers) {
- ft_head = 0;
- }
- return ft_buffer[ft_head];
- case ft_queue_tail:
- if (++ft_tail >= ft_nr_buffers) {
- ft_tail = 0;
- }
- return ft_buffer[ft_tail];
- default:
- return NULL;
- }
-}
-int ftape_buffer_id(ft_buffer_queue_t pos)
-{
- switch(pos) {
- case ft_queue_head: return ft_head;
- case ft_queue_tail: return ft_tail;
- default: return -1;
- }
-}
-buffer_struct *ftape_get_buffer(ft_buffer_queue_t pos)
-{
- switch(pos) {
- case ft_queue_head: return ft_buffer[ft_head];
- case ft_queue_tail: return ft_buffer[ft_tail];
- default: return NULL;
- }
-}
-void ftape_reset_buffer(void)
-{
- ft_head = ft_tail = 0;
-}
-
-buffer_state_enum ftape_set_state(buffer_state_enum new_state)
-{
- buffer_state_enum old_state = ft_driver_state;
-
- ft_driver_state = new_state;
- return old_state;
-}
-/* Calculate Floppy Disk Controller and DMA parameters for a segment.
- * head: selects buffer struct in array.
- * offset: number of physical sectors to skip (including bad ones).
- * count: number of physical sectors to handle (including bad ones).
- */
-static int setup_segment(buffer_struct * buff,
- int segment_id,
- unsigned int sector_offset,
- unsigned int sector_count,
- int retry)
-{
- SectorMap offset_mask;
- SectorMap mask;
- TRACE_FUN(ft_t_any);
-
- buff->segment_id = segment_id;
- buff->sector_offset = sector_offset;
- buff->remaining = sector_count;
- buff->head = segment_id / ftape_segments_per_head;
- buff->cyl = (segment_id % ftape_segments_per_head) / ftape_segments_per_cylinder;
- buff->sect = (segment_id % ftape_segments_per_cylinder) * FT_SECTORS_PER_SEGMENT + 1;
- buff->deleted = 0;
- offset_mask = (1 << buff->sector_offset) - 1;
- mask = ftape_get_bad_sector_entry(segment_id) & offset_mask;
- while (mask) {
- if (mask & 1) {
- offset_mask >>= 1; /* don't count bad sector */
- }
- mask >>= 1;
- }
- buff->data_offset = count_ones(offset_mask); /* good sectors to skip */
- buff->ptr = buff->address + buff->data_offset * FT_SECTOR_SIZE;
- TRACE(ft_t_flow, "data offset = %d sectors", buff->data_offset);
- if (retry) {
- buff->soft_error_map &= offset_mask; /* keep skipped part */
- } else {
- buff->hard_error_map = buff->soft_error_map = 0;
- }
- buff->bad_sector_map = ftape_get_bad_sector_entry(buff->segment_id);
- if (buff->bad_sector_map != 0) {
- TRACE(ft_t_noise, "segment: %d, bad sector map: %08lx",
- buff->segment_id, (long)buff->bad_sector_map);
- } else {
- TRACE(ft_t_flow, "segment: %d", buff->segment_id);
- }
- if (buff->sector_offset > 0) {
- buff->bad_sector_map >>= buff->sector_offset;
- }
- if (buff->sector_offset != 0 || buff->remaining != FT_SECTORS_PER_SEGMENT) {
- TRACE(ft_t_flow, "sector offset = %d, count = %d",
- buff->sector_offset, buff->remaining);
- }
- /* Segments with 3 or less sectors are not written with valid
- * data because there is no space left for the ecc. The
- * data written is whatever happens to be in the buffer.
- * Reading such a segment will return a zero byte-count.
- * To allow us to read/write segments with all bad sectors
- * we fake one readable sector in the segment. This
- * prevents having to handle these segments in a very
- * special way. It is not important if the reading of this
- * bad sector fails or not (the data is ignored). It is
- * only read to keep the driver running.
- *
- * The QIC-40/80 spec. has no information on how to handle
- * this case, so this is my interpretation.
- */
- if (buff->bad_sector_map == EMPTY_SEGMENT) {
- TRACE(ft_t_flow, "empty segment %d, fake first sector good",
- buff->segment_id);
- if (buff->ptr != buff->address) {
- TRACE(ft_t_bug, "This is a bug: %p/%p",
- buff->ptr, buff->address);
- }
- buff->bad_sector_map = FAKE_SEGMENT;
- }
- fdc_setup_error = 0;
- buff->next_segment = segment_id + 1;
- TRACE_EXIT 0;
-}
-
-/* Calculate Floppy Disk Controller and DMA parameters for a new segment.
- */
-int ftape_setup_new_segment(buffer_struct * buff, int segment_id, int skip)
-{
- int result = 0;
- static int old_segment_id = -1;
- static buffer_state_enum old_ft_driver_state = idle;
- int retry = 0;
- unsigned offset = 0;
- int count = FT_SECTORS_PER_SEGMENT;
- TRACE_FUN(ft_t_flow);
-
- TRACE(ft_t_flow, "%s segment %d (old = %d)",
- (ft_driver_state == reading || ft_driver_state == verifying)
- ? "reading" : "writing",
- segment_id, old_segment_id);
- if (ft_driver_state != old_ft_driver_state) { /* when verifying */
- old_segment_id = -1;
- old_ft_driver_state = ft_driver_state;
- }
- if (segment_id == old_segment_id) {
- ++buff->retry;
- ++ft_history.retries;
- TRACE(ft_t_flow, "setting up for retry nr %d", buff->retry);
- retry = 1;
- if (skip && buff->skip > 0) { /* allow skip on retry */
- offset = buff->skip;
- count -= offset;
- TRACE(ft_t_flow, "skipping %d sectors", offset);
- }
- } else {
- buff->retry = 0;
- buff->skip = 0;
- old_segment_id = segment_id;
- }
- result = setup_segment(buff, segment_id, offset, count, retry);
- TRACE_EXIT result;
-}
-
-/* Determine size of next cluster of good sectors.
- */
-int ftape_calc_next_cluster(buffer_struct * buff)
-{
- /* Skip bad sectors.
- */
- while (buff->remaining > 0 && (buff->bad_sector_map & 1) != 0) {
- buff->bad_sector_map >>= 1;
- ++buff->sector_offset;
- --buff->remaining;
- }
- /* Find next cluster of good sectors
- */
- if (buff->bad_sector_map == 0) { /* speed up */
- buff->sector_count = buff->remaining;
- } else {
- SectorMap map = buff->bad_sector_map;
-
- buff->sector_count = 0;
- while (buff->sector_count < buff->remaining && (map & 1) == 0) {
- ++buff->sector_count;
- map >>= 1;
- }
- }
- return buff->sector_count;
-}
-
-/* if just passed the last segment on a track, wait for BOT
- * or EOT mark.
- */
-int ftape_handle_logical_eot(void)
-{
- TRACE_FUN(ft_t_flow);
-
- if (ft_runner_status == logical_eot) {
- int status;
-
- TRACE(ft_t_noise, "tape at logical EOT");
- TRACE_CATCH(ftape_ready_wait(ftape_timeout.seek, &status),);
- if ((status & (QIC_STATUS_AT_BOT | QIC_STATUS_AT_EOT)) == 0) {
- TRACE_ABORT(-EIO, ft_t_err, "eot/bot not reached");
- }
- ft_runner_status = end_of_tape;
- }
- if (ft_runner_status == end_of_tape) {
- TRACE(ft_t_noise, "runner stopped because of logical EOT");
- ft_runner_status = idle;
- }
- TRACE_EXIT 0;
-}
-
-static int check_bot_eot(int status)
-{
- TRACE_FUN(ft_t_flow);
-
- if (status & (QIC_STATUS_AT_BOT | QIC_STATUS_AT_EOT)) {
- ft_location.bot = ((ft_location.track & 1) == 0 ?
- (status & QIC_STATUS_AT_BOT) != 0:
- (status & QIC_STATUS_AT_EOT) != 0);
- ft_location.eot = !ft_location.bot;
- ft_location.segment = (ft_location.track +
- (ft_location.bot ? 0 : 1)) * ft_segments_per_track - 1;
- ft_location.sector = -1;
- ft_location.known = 1;
- TRACE(ft_t_flow, "tape at logical %s",
- ft_location.bot ? "bot" : "eot");
- TRACE(ft_t_flow, "segment = %d", ft_location.segment);
- } else {
- ft_location.known = 0;
- }
- TRACE_EXIT ft_location.known;
-}
-
-/* Read Id of first sector passing tape head.
- */
-static int ftape_read_id(void)
-{
- int status;
- __u8 out[2];
- TRACE_FUN(ft_t_any);
-
- /* Assume tape is running on entry, be able to handle
- * situation where it stopped or is stopping.
- */
- ft_location.known = 0; /* default is location not known */
- out[0] = FDC_READID;
- out[1] = ft_drive_sel;
- TRACE_CATCH(fdc_command(out, 2),);
- switch (fdc_interrupt_wait(20 * FT_SECOND)) {
- case 0:
- if (fdc_sect == 0) {
- if (ftape_report_drive_status(&status) >= 0 &&
- (status & QIC_STATUS_READY)) {
- ftape_tape_running = 0;
- TRACE(ft_t_flow, "tape has stopped");
- check_bot_eot(status);
- }
- } else {
- ft_location.known = 1;
- ft_location.segment = (ftape_segments_per_head
- * fdc_head
- + ftape_segments_per_cylinder
- * fdc_cyl
- + (fdc_sect - 1)
- / FT_SECTORS_PER_SEGMENT);
- ft_location.sector = ((fdc_sect - 1)
- % FT_SECTORS_PER_SEGMENT);
- ft_location.eot = ft_location.bot = 0;
- }
- break;
- case -ETIME:
- /* Didn't find id on tape, must be near end: Wait
- * until stopped.
- */
- if (ftape_ready_wait(FT_FOREVER, &status) >= 0) {
- ftape_tape_running = 0;
- TRACE(ft_t_flow, "tape has stopped");
- check_bot_eot(status);
- }
- break;
- default:
- /* Interrupted or otherwise failing
- * fdc_interrupt_wait()
- */
- TRACE(ft_t_err, "fdc_interrupt_wait failed");
- break;
- }
- if (!ft_location.known) {
- TRACE_ABORT(-EIO, ft_t_flow, "no id found");
- }
- if (ft_location.sector == 0) {
- TRACE(ft_t_flow, "passing segment %d/%d",
- ft_location.segment, ft_location.sector);
- } else {
- TRACE(ft_t_fdc_dma, "passing segment %d/%d",
- ft_location.segment, ft_location.sector);
- }
- TRACE_EXIT 0;
-}
-
-static int logical_forward(void)
-{
- ftape_tape_running = 1;
- return ftape_command(QIC_LOGICAL_FORWARD);
-}
-
-int ftape_stop_tape(int *pstatus)
-{
- int retry = 0;
- int result;
- TRACE_FUN(ft_t_flow);
-
- do {
- result = ftape_command_wait(QIC_STOP_TAPE,
- ftape_timeout.stop, pstatus);
- if (result == 0) {
- if ((*pstatus & QIC_STATUS_READY) == 0) {
- result = -EIO;
- } else {
- ftape_tape_running = 0;
- }
- }
- } while (result < 0 && ++retry <= 3);
- if (result < 0) {
- TRACE(ft_t_err, "failed ! (fatal)");
- }
- TRACE_EXIT result;
-}
-
-int ftape_dumb_stop(void)
-{
- int result;
- int status;
- TRACE_FUN(ft_t_flow);
-
- /* Abort current fdc operation if it's busy (probably read
- * or write operation pending) with a reset.
- */
- if (fdc_ready_wait(100 /* usec */) < 0) {
- TRACE(ft_t_noise, "aborting fdc operation");
- fdc_reset();
- }
- /* Reading id's after the last segment on a track may fail
- * but eventually the drive will become ready (logical eot).
- */
- result = ftape_report_drive_status(&status);
- ft_location.known = 0;
- do {
- if (result == 0 && status & QIC_STATUS_READY) {
- /* Tape is not running any more.
- */
- TRACE(ft_t_noise, "tape already halted");
- check_bot_eot(status);
- ftape_tape_running = 0;
- } else if (ftape_tape_running) {
- /* Tape is (was) still moving.
- */
-#ifdef TESTING
- ftape_read_id();
-#endif
- result = ftape_stop_tape(&status);
- } else {
- /* Tape not yet ready but stopped.
- */
- result = ftape_ready_wait(ftape_timeout.pause,&status);
- }
- } while (ftape_tape_running
- && !(sigtestsetmask(&current->pending.signal, _NEVER_BLOCK)));
-#ifndef TESTING
- ft_location.known = 0;
-#endif
- if (ft_runner_status == aborting || ft_runner_status == do_abort) {
- ft_runner_status = idle;
- }
- TRACE_EXIT result;
-}
-
-/* Wait until runner has finished tail buffer.
- *
- */
-int ftape_wait_segment(buffer_state_enum state)
-{
- int status;
- int result = 0;
- TRACE_FUN(ft_t_flow);
-
- while (ft_buffer[ft_tail]->status == state) {
- TRACE(ft_t_flow, "state: %d", ft_buffer[ft_tail]->status);
- /* First buffer still being worked on, wait up to timeout.
- *
- * Note: we check two times for being killed. 50
- * seconds are quite long. Note that
- * fdc_interrupt_wait() is not killable by any
- * means. ftape_read_segment() wants us to return
- * -EINTR in case of a signal.
- */
- FT_SIGNAL_EXIT(_DONT_BLOCK);
- result = fdc_interrupt_wait(50 * FT_SECOND);
- FT_SIGNAL_EXIT(_DONT_BLOCK);
- if (result < 0) {
- TRACE_ABORT(result,
- ft_t_err, "fdc_interrupt_wait failed");
- }
- if (fdc_setup_error) {
- /* recover... FIXME */
- TRACE_ABORT(-EIO, ft_t_err, "setup error");
- }
- }
- if (ft_buffer[ft_tail]->status != error) {
- TRACE_EXIT 0;
- }
- TRACE_CATCH(ftape_report_drive_status(&status),);
- TRACE(ft_t_noise, "ftape_report_drive_status: 0x%02x", status);
- if ((status & QIC_STATUS_READY) &&
- (status & QIC_STATUS_ERROR)) {
- unsigned int error;
- qic117_cmd_t command;
-
- /* Report and clear error state.
- * In case the drive can't operate at the selected
- * rate, select the next lower data rate.
- */
- ftape_report_error(&error, &command, 1);
- if (error == 31 && command == QIC_LOGICAL_FORWARD) {
- /* drive does not accept this data rate */
- if (ft_data_rate > 250) {
- TRACE(ft_t_info,
- "Probable data rate conflict");
- TRACE(ft_t_info,
- "Lowering data rate to %d Kbps",
- ft_data_rate / 2);
- ftape_half_data_rate();
- if (ft_buffer[ft_tail]->retry > 0) {
- /* give it a chance */
- --ft_buffer[ft_tail]->retry;
- }
- } else {
- /* no rate is accepted... */
- TRACE(ft_t_err, "We're dead :(");
- }
- } else {
- TRACE(ft_t_err, "Unknown error");
- }
- TRACE_EXIT -EIO; /* g.p. error */
- }
- TRACE_EXIT 0;
-}
-
-/* forward */ static int seek_forward(int segment_id, int fast);
-
-static int fast_seek(int count, int reverse)
-{
- int result = 0;
- int status;
- TRACE_FUN(ft_t_flow);
-
- if (count > 0) {
- /* If positioned at begin or end of tape, fast seeking needs
- * special treatment.
- * Starting from logical bot needs a (slow) seek to the first
- * segment before the high speed seek. Most drives do this
- * automatically but some older don't, so we treat them
- * all the same.
- * Starting from logical eot is even more difficult because
- * we cannot (slow) reverse seek to the last segment.
- * TO BE IMPLEMENTED.
- */
- inhibit_correction = 0;
- if (ft_location.known &&
- ((ft_location.bot && !reverse) ||
- (ft_location.eot && reverse))) {
- if (!reverse) {
- /* (slow) skip to first segment on a track
- */
- seek_forward(ft_location.track * ft_segments_per_track, 0);
- --count;
- } else {
- /* When seeking backwards from
- * end-of-tape the number of erased
- * gaps found seems to be higher than
- * expected. Therefor the drive must
- * skip some more segments than
- * calculated, but we don't know how
- * many. Thus we will prevent the
- * re-calculation of offset and
- * overshoot when seeking backwards.
- */
- inhibit_correction = 1;
- count += 3; /* best guess */
- }
- }
- } else {
- TRACE(ft_t_flow, "warning: zero or negative count: %d", count);
- }
- if (count > 0) {
- int i;
- int nibbles = count > 255 ? 3 : 2;
-
- if (count > 4095) {
- TRACE(ft_t_noise, "skipping clipped at 4095 segment");
- count = 4095;
- }
- /* Issue this tape command first. */
- if (!reverse) {
- TRACE(ft_t_noise, "skipping %d segment(s)", count);
- result = ftape_command(nibbles == 3 ?
- QIC_SKIP_EXTENDED_FORWARD : QIC_SKIP_FORWARD);
- } else {
- TRACE(ft_t_noise, "backing up %d segment(s)", count);
- result = ftape_command(nibbles == 3 ?
- QIC_SKIP_EXTENDED_REVERSE : QIC_SKIP_REVERSE);
- }
- if (result < 0) {
- TRACE(ft_t_noise, "Skip command failed");
- } else {
- --count; /* 0 means one gap etc. */
- for (i = 0; i < nibbles; ++i) {
- if (result >= 0) {
- result = ftape_parameter(count & 15);
- count /= 16;
- }
- }
- result = ftape_ready_wait(ftape_timeout.rewind, &status);
- if (result >= 0) {
- ftape_tape_running = 0;
- }
- }
- }
- TRACE_EXIT result;
-}
-
-static int validate(int id)
-{
- /* Check to see if position found is off-track as reported
- * once. Because all tracks in one direction lie next to
- * each other, if off-track the error will be approximately
- * 2 * ft_segments_per_track.
- */
- if (ft_location.track == -1) {
- return 1; /* unforseen situation, don't generate error */
- } else {
- /* Use margin of ft_segments_per_track on both sides
- * because ftape needs some margin and the error we're
- * looking for is much larger !
- */
- int lo = (ft_location.track - 1) * ft_segments_per_track;
- int hi = (ft_location.track + 2) * ft_segments_per_track;
-
- return (id >= lo && id < hi);
- }
-}
-
-static int seek_forward(int segment_id, int fast)
-{
- int failures = 0;
- int count;
- static int margin = 1; /* fixed: stop this before target */
- static int overshoot = 1;
- static int min_count = 8;
- int expected = -1;
- int target = segment_id - margin;
- int fast_seeking;
- int prev_segment = ft_location.segment;
- TRACE_FUN(ft_t_flow);
-
- if (!ft_location.known) {
- TRACE_ABORT(-EIO, ft_t_err,
- "fatal: cannot seek from unknown location");
- }
- if (!validate(segment_id)) {
- ftape_sleep(1 * FT_SECOND);
- ft_failure = 1;
- TRACE_ABORT(-EIO, ft_t_err,
- "fatal: head off track (bad hardware?)");
- }
- TRACE(ft_t_noise, "from %d/%d to %d/0 - %d",
- ft_location.segment, ft_location.sector,segment_id,margin);
- count = target - ft_location.segment - overshoot;
- fast_seeking = (fast &&
- count > (min_count + (ft_location.bot ? 1 : 0)));
- if (fast_seeking) {
- TRACE(ft_t_noise, "fast skipping %d segments", count);
- expected = segment_id - margin;
- fast_seek(count, 0);
- }
- if (!ftape_tape_running) {
- logical_forward();
- }
- while (ft_location.segment < segment_id) {
- /* This requires at least one sector in a (bad) segment to
- * have a valid and readable sector id !
- * It looks like this is not guaranteed, so we must try
- * to find a way to skip an EMPTY_SEGMENT. !!! FIXME !!!
- */
- if (ftape_read_id() < 0 || !ft_location.known ||
- sigtestsetmask(&current->pending.signal, _DONT_BLOCK)) {
- ft_location.known = 0;
- if (!ftape_tape_running ||
- ++failures > FT_SECTORS_PER_SEGMENT) {
- TRACE_ABORT(-EIO, ft_t_err,
- "read_id failed completely");
- }
- FT_SIGNAL_EXIT(_DONT_BLOCK);
- TRACE(ft_t_flow, "read_id failed, retry (%d)",
- failures);
- continue;
- }
- if (fast_seeking) {
- TRACE(ft_t_noise, "ended at %d/%d (%d,%d)",
- ft_location.segment, ft_location.sector,
- overshoot, inhibit_correction);
- if (!inhibit_correction &&
- (ft_location.segment < expected ||
- ft_location.segment > expected + margin)) {
- int error = ft_location.segment - expected;
- TRACE(ft_t_noise,
- "adjusting overshoot from %d to %d",
- overshoot, overshoot + error);
- overshoot += error;
- /* All overshoots have the same
- * direction, so it should never
- * become negative, but who knows.
- */
- if (overshoot < -5 ||
- overshoot > OVERSHOOT_LIMIT) {
- if (overshoot < 0) {
- /* keep sane value */
- overshoot = -5;
- } else {
- /* keep sane value */
- overshoot = OVERSHOOT_LIMIT;
- }
- TRACE(ft_t_noise,
- "clipped overshoot to %d",
- overshoot);
- }
- }
- fast_seeking = 0;
- }
- if (ft_location.known) {
- if (ft_location.segment > prev_segment + 1) {
- TRACE(ft_t_noise,
- "missed segment %d while skipping",
- prev_segment + 1);
- }
- prev_segment = ft_location.segment;
- }
- }
- if (ft_location.segment > segment_id) {
- TRACE_ABORT(-EIO,
- ft_t_noise, "failed: skip ended at segment %d/%d",
- ft_location.segment, ft_location.sector);
- }
- TRACE_EXIT 0;
-}
-
-static int skip_reverse(int segment_id, int *pstatus)
-{
- int failures = 0;
- static int overshoot = 1;
- static int min_rewind = 2; /* 1 + overshoot */
- static const int margin = 1; /* stop this before target */
- int expected = 0;
- int count = 1;
- int short_seek;
- int target = segment_id - margin;
- TRACE_FUN(ft_t_flow);
-
- if (ft_location.known && !validate(segment_id)) {
- ftape_sleep(1 * FT_SECOND);
- ft_failure = 1;
- TRACE_ABORT(-EIO, ft_t_err,
- "fatal: head off track (bad hardware?)");
- }
- do {
- if (!ft_location.known) {
- TRACE(ft_t_warn, "warning: location not known");
- }
- TRACE(ft_t_noise, "from %d/%d to %d/0 - %d",
- ft_location.segment, ft_location.sector,
- segment_id, margin);
- /* min_rewind == 1 + overshoot_when_doing_minimum_rewind
- * overshoot == overshoot_when_doing_larger_rewind
- * Initially min_rewind == 1 + overshoot, optimization
- * of both values will be done separately.
- * overshoot and min_rewind can be negative as both are
- * sums of three components:
- * any_overshoot == rewind_overshoot -
- * stop_overshoot -
- * start_overshoot
- */
- if (ft_location.segment - target - (min_rewind - 1) < 1) {
- short_seek = 1;
- } else {
- count = ft_location.segment - target - overshoot;
- short_seek = (count < 1);
- }
- if (short_seek) {
- count = 1; /* do shortest rewind */
- expected = ft_location.segment - min_rewind;
- if (expected/ft_segments_per_track != ft_location.track) {
- expected = (ft_location.track *
- ft_segments_per_track);
- }
- } else {
- expected = target;
- }
- fast_seek(count, 1);
- logical_forward();
- if (ftape_read_id() < 0 || !ft_location.known ||
- (sigtestsetmask(&current->pending.signal, _DONT_BLOCK))) {
- if ((!ftape_tape_running && !ft_location.known) ||
- ++failures > FT_SECTORS_PER_SEGMENT) {
- TRACE_ABORT(-EIO, ft_t_err,
- "read_id failed completely");
- }
- FT_SIGNAL_EXIT(_DONT_BLOCK);
- TRACE_CATCH(ftape_report_drive_status(pstatus),);
- TRACE(ft_t_noise, "ftape_read_id failed, retry (%d)",
- failures);
- continue;
- }
- TRACE(ft_t_noise, "ended at %d/%d (%d,%d,%d)",
- ft_location.segment, ft_location.sector,
- min_rewind, overshoot, inhibit_correction);
- if (!inhibit_correction &&
- (ft_location.segment < expected ||
- ft_location.segment > expected + margin)) {
- int error = expected - ft_location.segment;
- if (short_seek) {
- TRACE(ft_t_noise,
- "adjusting min_rewind from %d to %d",
- min_rewind, min_rewind + error);
- min_rewind += error;
- if (min_rewind < -5) {
- /* is this right ? FIXME ! */
- /* keep sane value */
- min_rewind = -5;
- TRACE(ft_t_noise,
- "clipped min_rewind to %d",
- min_rewind);
- }
- } else {
- TRACE(ft_t_noise,
- "adjusting overshoot from %d to %d",
- overshoot, overshoot + error);
- overshoot += error;
- if (overshoot < -5 ||
- overshoot > OVERSHOOT_LIMIT) {
- if (overshoot < 0) {
- /* keep sane value */
- overshoot = -5;
- } else {
- /* keep sane value */
- overshoot = OVERSHOOT_LIMIT;
- }
- TRACE(ft_t_noise,
- "clipped overshoot to %d",
- overshoot);
- }
- }
- }
- } while (ft_location.segment > segment_id);
- if (ft_location.known) {
- TRACE(ft_t_noise, "current location: %d/%d",
- ft_location.segment, ft_location.sector);
- }
- TRACE_EXIT 0;
-}
-
-static int determine_position(void)
-{
- int retry = 0;
- int status;
- int result;
- TRACE_FUN(ft_t_flow);
-
- if (!ftape_tape_running) {
- /* This should only happen if tape is stopped by isr.
- */
- TRACE(ft_t_flow, "waiting for tape stop");
- if (ftape_ready_wait(ftape_timeout.pause, &status) < 0) {
- TRACE(ft_t_flow, "drive still running (fatal)");
- ftape_tape_running = 1; /* ? */
- }
- } else {
- ftape_report_drive_status(&status);
- }
- if (status & QIC_STATUS_READY) {
- /* Drive must be ready to check error state !
- */
- TRACE(ft_t_flow, "drive is ready");
- if (status & QIC_STATUS_ERROR) {
- unsigned int error;
- qic117_cmd_t command;
-
- /* Report and clear error state, try to continue.
- */
- TRACE(ft_t_flow, "error status set");
- ftape_report_error(&error, &command, 1);
- ftape_ready_wait(ftape_timeout.reset, &status);
- ftape_tape_running = 0; /* ? */
- }
- if (check_bot_eot(status)) {
- if (ft_location.bot) {
- if ((status & QIC_STATUS_READY) == 0) {
- /* tape moving away from
- * bot/eot, let's see if we
- * can catch up with the first
- * segment on this track.
- */
- } else {
- TRACE(ft_t_flow,
- "start tape from logical bot");
- logical_forward(); /* start moving */
- }
- } else {
- if ((status & QIC_STATUS_READY) == 0) {
- TRACE(ft_t_noise, "waiting for logical end of track");
- result = ftape_ready_wait(ftape_timeout.reset, &status);
- /* error handling needed ? */
- } else {
- TRACE(ft_t_noise,
- "tape at logical end of track");
- }
- }
- } else {
- TRACE(ft_t_flow, "start tape");
- logical_forward(); /* start moving */
- ft_location.known = 0; /* not cleared by logical forward ! */
- }
- }
- /* tape should be moving now, start reading id's
- */
- while (!ft_location.known &&
- retry++ < FT_SECTORS_PER_SEGMENT &&
- (result = ftape_read_id()) < 0) {
-
- TRACE(ft_t_flow, "location unknown");
-
- /* exit on signal
- */
- FT_SIGNAL_EXIT(_DONT_BLOCK);
-
- /* read-id somehow failed, tape may
- * have reached end or some other
- * error happened.
- */
- TRACE(ft_t_flow, "read-id failed");
- TRACE_CATCH(ftape_report_drive_status(&status),);
- TRACE(ft_t_err, "ftape_report_drive_status: 0x%02x", status);
- if (status & QIC_STATUS_READY) {
- ftape_tape_running = 0;
- TRACE(ft_t_noise, "tape stopped for unknown reason! "
- "status = 0x%02x", status);
- if (status & QIC_STATUS_ERROR ||
- !check_bot_eot(status)) {
- /* oops, tape stopped but not at end!
- */
- TRACE_EXIT -EIO;
- }
- }
- }
- TRACE(ft_t_flow,
- "tape is positioned at segment %d", ft_location.segment);
- TRACE_EXIT ft_location.known ? 0 : -EIO;
-}
-
-/* Get the tape running and position it just before the
- * requested segment.
- * Seek tape-track and reposition as needed.
- */
-int ftape_start_tape(int segment_id, int sector_offset)
-{
- int track = segment_id / ft_segments_per_track;
- int result = -EIO;
- int status;
- static int last_segment = -1;
- static int bad_bus_timing = 0;
- /* number of segments passing the head between starting the tape
- * and being able to access the first sector.
- */
- static int start_offset = 1;
- int retry;
- TRACE_FUN(ft_t_flow);
-
- /* If sector_offset > 0, seek into wanted segment instead of
- * into previous.
- * This allows error recovery if a part of the segment is bad
- * (erased) causing the tape drive to generate an index pulse
- * thus causing a no-data error before the requested sector
- * is reached.
- */
- ftape_tape_running = 0;
- TRACE(ft_t_noise, "target segment: %d/%d%s", segment_id, sector_offset,
- ft_buffer[ft_head]->retry > 0 ? " retry" : "");
- if (ft_buffer[ft_head]->retry > 0) { /* this is a retry */
- int dist = segment_id - last_segment;
-
- if ((int)ft_history.overrun_errors < overrun_count_offset) {
- overrun_count_offset = ft_history.overrun_errors;
- } else if (dist < 0 || dist > 50) {
- overrun_count_offset = ft_history.overrun_errors;
- } else if ((ft_history.overrun_errors -
- overrun_count_offset) >= 8) {
- if (ftape_increase_threshold() >= 0) {
- --ft_buffer[ft_head]->retry;
- overrun_count_offset =
- ft_history.overrun_errors;
- TRACE(ft_t_warn, "increased threshold because "
- "of excessive overrun errors");
- } else if (!bad_bus_timing && ft_data_rate >= 1000) {
- ftape_half_data_rate();
- --ft_buffer[ft_head]->retry;
- bad_bus_timing = 1;
- overrun_count_offset =
- ft_history.overrun_errors;
- TRACE(ft_t_warn, "reduced datarate because "
- "of excessive overrun errors");
- }
- }
- }
- last_segment = segment_id;
- if (ft_location.track != track ||
- (ftape_might_be_off_track && ft_buffer[ft_head]->retry== 0)) {
- /* current track unknown or not equal to destination
- */
- ftape_ready_wait(ftape_timeout.seek, &status);
- ftape_seek_head_to_track(track);
- /* overrun_count_offset = ft_history.overrun_errors; */
- }
- result = -EIO;
- retry = 0;
- while (result < 0 &&
- retry++ <= 5 &&
- !ft_failure &&
- !(sigtestsetmask(&current->pending.signal, _DONT_BLOCK))) {
-
- if (retry && start_offset < 5) {
- start_offset ++;
- }
- /* Check if we are able to catch the requested
- * segment in time.
- */
- if ((ft_location.known || (determine_position() == 0)) &&
- ft_location.segment >=
- (segment_id -
- ((ftape_tape_running || ft_location.bot)
- ? 0 : start_offset))) {
- /* Too far ahead (in or past target segment).
- */
- if (ftape_tape_running) {
- if ((result = ftape_stop_tape(&status)) < 0) {
- TRACE(ft_t_err,
- "stop tape failed with code %d",
- result);
- break;
- }
- TRACE(ft_t_noise, "tape stopped");
- ftape_tape_running = 0;
- }
- TRACE(ft_t_noise, "repositioning");
- ++ft_history.rewinds;
- if (segment_id % ft_segments_per_track < start_offset){
- TRACE(ft_t_noise, "end of track condition\n"
- KERN_INFO "segment_id : %d\n"
- KERN_INFO "ft_segments_per_track: %d\n"
- KERN_INFO "start_offset : %d",
- segment_id, ft_segments_per_track,
- start_offset);
-
- /* If seeking to first segments on
- * track better do a complete rewind
- * to logical begin of track to get a
- * more steady tape motion.
- */
- result = ftape_command_wait(
- (ft_location.track & 1)
- ? QIC_PHYSICAL_FORWARD
- : QIC_PHYSICAL_REVERSE,
- ftape_timeout.rewind, &status);
- check_bot_eot(status); /* update location */
- } else {
- result= skip_reverse(segment_id - start_offset,
- &status);
- }
- }
- if (!ft_location.known) {
- TRACE(ft_t_bug, "panic: location not known");
- result = -EIO;
- continue; /* while() will check for failure */
- }
- TRACE(ft_t_noise, "current segment: %d/%d",
- ft_location.segment, ft_location.sector);
- /* We're on the right track somewhere before the
- * wanted segment. Start tape movement if needed and
- * skip to just before or inside the requested
- * segment. Keep tape running.
- */
- result = 0;
- if (ft_location.segment <
- (segment_id - ((ftape_tape_running || ft_location.bot)
- ? 0 : start_offset))) {
- if (sector_offset > 0) {
- result = seek_forward(segment_id,
- retry <= 3);
- } else {
- result = seek_forward(segment_id - 1,
- retry <= 3);
- }
- }
- if (result == 0 &&
- ft_location.segment !=
- (segment_id - (sector_offset > 0 ? 0 : 1))) {
- result = -EIO;
- }
- }
- if (result < 0) {
- TRACE(ft_t_err, "failed to reposition");
- } else {
- ft_runner_status = running;
- }
- TRACE_EXIT result;
-}