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199 |
simons |
/*
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* Copyright (C) 1993-1995 Bas Laarhoven.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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$Source: /home/marcus/revision_ctrl_test/oc_cvs/cvs/or1k/uclinux/uClinux-2.0.x/drivers/char/ftape/ftape-rw.c,v $
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$Author: simons $
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*
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$Revision: 1.1.1.1 $
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$Date: 2001-09-10 07:44:17 $
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$State: Exp $
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*
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* This file contains some common code for the segment read and segment
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* write routines for the QIC-117 floppy-tape driver for Linux.
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*/
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/ftape.h>
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#include "tracing.h"
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#include "ftape-rw.h"
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#include "fdc-io.h"
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#include "kernel-interface.h"
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#include "qic117.h"
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#include "ftape-io.h"
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#include "ftape-ctl.h"
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#include "ftape-read.h"
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#include "ftape-eof.h"
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#include "ecc.h"
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#include "ftape-bsm.h"
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/* Global vars.
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*/
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volatile enum runner_status_enum runner_status = idle;
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byte deblock_buffer[(SECTORS_PER_SEGMENT - 3) * SECTOR_SIZE];
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byte scratch_buffer[(SECTORS_PER_SEGMENT - 3) * SECTOR_SIZE];
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buffer_struct buffer[NR_BUFFERS];
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struct wait_queue *wait_intr = NULL;
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volatile int head;
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volatile int tail; /* not volatile but need same type as head */
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int fdc_setup_error;
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ftape_last_segment_struct ftape_last_segment;
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int header_segment_1 = -1;
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int header_segment_2 = -1;
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int used_header_segment = -1;
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location_record location =
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{-1, 0};
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volatile int tape_running = 0;
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format_type format_code;
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/* Local vars.
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*/
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static int overrun_count_offset = 0;
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static int inhibit_correction = 0;
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/* Increment cyclic buffer nr.
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*/
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buffer_struct *
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next_buffer(volatile int *x)
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{
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if (++*x >= NR_BUFFERS) {
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*x = 0;
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}
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return &buffer[*x];
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}
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int valid_segment_no(unsigned segment)
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{
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return (segment >= first_data_segment && segment <= ftape_last_segment.id);
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}
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/* Count nr of 1's in pattern.
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*/
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int count_ones(unsigned long mask)
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{
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int bits;
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for (bits = 0; mask != 0; mask >>= 1) {
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if (mask & 1) {
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++bits;
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}
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}
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return bits;
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}
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/* Calculate Floppy Disk Controller and DMA parameters for a segment.
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* head: selects buffer struct in array.
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* offset: number of physical sectors to skip (including bad ones).
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* count: number of physical sectors to handle (including bad ones).
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*/
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static int setup_segment(buffer_struct * buff, unsigned int segment_id,
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unsigned int sector_offset, unsigned int sector_count, int retry)
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{
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TRACE_FUN(8, "setup_segment");
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unsigned long offset_mask;
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unsigned long mask;
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buff->segment_id = segment_id;
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buff->sector_offset = sector_offset;
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buff->remaining = sector_count;
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buff->head = segment_id / segments_per_head;
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buff->cyl = (segment_id % segments_per_head) / segments_per_cylinder;
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buff->sect = (segment_id % segments_per_cylinder) * SECTORS_PER_SEGMENT + 1;
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buff->deleted = 0;
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offset_mask = (1 << buff->sector_offset) - 1;
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mask = get_bad_sector_entry(segment_id) & offset_mask;
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while (mask) {
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if (mask & 1) {
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offset_mask >>= 1; /* don't count bad sector */
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}
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mask >>= 1;
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}
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buff->data_offset = count_ones(offset_mask); /* good sectors to skip */
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buff->ptr = buff->address + buff->data_offset * SECTOR_SIZE;
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TRACEx1(5, "data offset = %d sectors", buff->data_offset);
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if (retry) {
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buff->soft_error_map &= offset_mask; /* keep skipped part */
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} else {
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buff->hard_error_map = buff->soft_error_map = 0;
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}
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buff->bad_sector_map = get_bad_sector_entry(buff->segment_id);
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if (buff->bad_sector_map != 0) {
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TRACEx2(4, "segment: %d, bad sector map: %08lx",
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buff->segment_id, buff->bad_sector_map);
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} else {
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TRACEx1(5, "segment: %d", buff->segment_id);
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}
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if (buff->sector_offset > 0) {
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buff->bad_sector_map >>= buff->sector_offset;
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}
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if (buff->sector_offset != 0 || buff->remaining != SECTORS_PER_SEGMENT) {
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TRACEx2(5, "sector offset = %d, count = %d",
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buff->sector_offset, buff->remaining);
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}
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/*
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* Segments with 3 or less sectors are not written with
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* valid data because there is no space left for the ecc.
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* The data written is whatever happens to be in the buffer.
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* Reading such a segment will return a zero byte-count.
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* To allow us to read/write segments with all bad sectors
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* we fake one readable sector in the segment. This prevents
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* having to handle these segments in a very special way.
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* It is not important if the reading of this bad sector
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* fails or not (the data is ignored). It is only read to
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* keep the driver running.
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* The QIC-40/80 spec. has no information on how to handle
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* this case, so this is my interpretation.
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*/
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if (buff->bad_sector_map == EMPTY_SEGMENT) {
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TRACE(5, "empty segment, fake first sector good");
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buff->bad_sector_map = FAKE_SEGMENT;
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}
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fdc_setup_error = 0;
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buff->next_segment = segment_id + 1;
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TRACE_EXIT;
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return 0;
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}
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| 172 |
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/* Calculate Floppy Disk Controller and DMA parameters for a new segment.
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*/
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int setup_new_segment(buffer_struct * buff, unsigned int segment_id, int skip)
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{
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TRACE_FUN(5, "setup_new_segment");
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int result = 0;
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static int old_segment_id = -1;
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static int old_ftape_state = idle;
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int retry = 0;
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unsigned offset = 0;
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int count = SECTORS_PER_SEGMENT;
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TRACEx3(5, "%s segment %d (old = %d)",
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(ftape_state == reading) ? "reading" : "writing",
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segment_id, old_segment_id);
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if (ftape_state != old_ftape_state) { /* when verifying */
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old_segment_id = -1;
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old_ftape_state = ftape_state;
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}
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if (segment_id == old_segment_id) {
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++buff->retry;
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++history.retries;
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TRACEx1(5, "setting up for retry nr %d", buff->retry);
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retry = 1;
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if (skip && buff->skip > 0) { /* allow skip on retry */
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offset = buff->skip;
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count -= offset;
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TRACEx1(5, "skipping %d sectors", offset);
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}
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} else {
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buff->retry = 0;
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buff->skip = 0;
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old_segment_id = segment_id;
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}
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result = setup_segment(buff, segment_id, offset, count, retry);
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TRACE_EXIT;
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return result;
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}
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/* Determine size of next cluster of good sectors.
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*/
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int calc_next_cluster(buffer_struct * buff)
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{
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/* Skip bad sectors.
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*/
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while (buff->remaining > 0 && (buff->bad_sector_map & 1) != 0) {
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buff->bad_sector_map >>= 1;
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++buff->sector_offset;
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--buff->remaining;
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}
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/* Find next cluster of good sectors
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*/
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if (buff->bad_sector_map == 0) { /* speed up */
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buff->sector_count = buff->remaining;
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} else {
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unsigned long map = buff->bad_sector_map;
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buff->sector_count = 0;
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while (buff->sector_count < buff->remaining && (map & 1) == 0) {
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++buff->sector_count;
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map >>= 1;
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}
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| 235 |
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}
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| 236 |
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return buff->sector_count;
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| 237 |
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}
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| 238 |
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| 239 |
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int check_bot_eot(int status)
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{
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| 241 |
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TRACE_FUN(5, "check_bot_eot");
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| 242 |
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| 243 |
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if (status & (QIC_STATUS_AT_BOT | QIC_STATUS_AT_EOT)) {
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location.bot = ((location.track & 1) == 0 ?
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(status & QIC_STATUS_AT_BOT) :
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(status & QIC_STATUS_AT_EOT));
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location.eot = !location.bot;
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location.segment = (location.track +
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(location.bot ? 0 : 1)) * segments_per_track - 1;
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location.sector = -1;
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| 251 |
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location.known = 1;
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TRACEx1(5, "tape at logical %s", location.bot ? "bot" : "eot");
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TRACEx1(5, "segment = %d", location.segment);
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| 254 |
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} else {
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| 255 |
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location.known = 0;
|
| 256 |
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}
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| 257 |
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TRACE_EXIT;
|
| 258 |
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return location.known;
|
| 259 |
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}
|
| 260 |
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| 261 |
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/* Read Id of first sector passing tape head.
|
| 262 |
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*/
|
| 263 |
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int ftape_read_id(void)
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| 264 |
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{
|
| 265 |
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TRACE_FUN(8, "ftape_read_id");
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| 266 |
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int result;
|
| 267 |
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int status;
|
| 268 |
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byte out[2];
|
| 269 |
|
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|
| 270 |
|
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/* Assume tape is running on entry, be able to handle
|
| 271 |
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* situation where it stopped or is stopping.
|
| 272 |
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*/
|
| 273 |
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location.known = 0; /* default is location not known */
|
| 274 |
|
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out[0] = FDC_READID;
|
| 275 |
|
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out[1] = FTAPE_UNIT;
|
| 276 |
|
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result = fdc_command(out, 2);
|
| 277 |
|
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if (result < 0) {
|
| 278 |
|
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TRACE(1, "fdc_command failed");
|
| 279 |
|
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} else {
|
| 280 |
|
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result = fdc_interrupt_wait(20 * SECOND);
|
| 281 |
|
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if (result == 0) {
|
| 282 |
|
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if (fdc_sect == 0) {
|
| 283 |
|
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result = ftape_report_drive_status(&status);
|
| 284 |
|
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if (result == 0) {
|
| 285 |
|
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if (status & QIC_STATUS_READY) {
|
| 286 |
|
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tape_running = 0;
|
| 287 |
|
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TRACE(5, "tape has stopped");
|
| 288 |
|
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check_bot_eot(status);
|
| 289 |
|
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if (!location.known) {
|
| 290 |
|
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result = -EIO;
|
| 291 |
|
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}
|
| 292 |
|
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} else {
|
| 293 |
|
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/* If read-id failed because of a hard or soft
|
| 294 |
|
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* error, return an error. Higher level must retry!
|
| 295 |
|
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*/
|
| 296 |
|
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result = -EIO;
|
| 297 |
|
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}
|
| 298 |
|
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}
|
| 299 |
|
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} else {
|
| 300 |
|
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location.known = 1;
|
| 301 |
|
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location.segment = (segments_per_head * fdc_head
|
| 302 |
|
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+ segments_per_cylinder * fdc_cyl
|
| 303 |
|
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+ (fdc_sect - 1) / SECTORS_PER_SEGMENT);
|
| 304 |
|
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location.sector = (fdc_sect - 1) % SECTORS_PER_SEGMENT;
|
| 305 |
|
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location.eot =
|
| 306 |
|
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location.bot = 0;
|
| 307 |
|
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}
|
| 308 |
|
|
} else if (result == -ETIME) {
|
| 309 |
|
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/* Didn't find id on tape, must be near end: Wait until stopped.
|
| 310 |
|
|
*/
|
| 311 |
|
|
result = ftape_ready_wait(FOREVER, &status);
|
| 312 |
|
|
if (result >= 0) {
|
| 313 |
|
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tape_running = 0;
|
| 314 |
|
|
TRACE(5, "tape has stopped");
|
| 315 |
|
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check_bot_eot(status);
|
| 316 |
|
|
if (!location.known) {
|
| 317 |
|
|
result = -EIO;
|
| 318 |
|
|
}
|
| 319 |
|
|
}
|
| 320 |
|
|
} else {
|
| 321 |
|
|
/* Interrupted or otherwise failing fdc_interrupt_wait()
|
| 322 |
|
|
*/
|
| 323 |
|
|
TRACE(1, "fdc_interrupt_wait failed :(");
|
| 324 |
|
|
result = -EIO;
|
| 325 |
|
|
}
|
| 326 |
|
|
}
|
| 327 |
|
|
if (!location.known) {
|
| 328 |
|
|
TRACE(5, "no id found");
|
| 329 |
|
|
} else {
|
| 330 |
|
|
if (location.sector == 0) {
|
| 331 |
|
|
TRACEx2(5, "passing segment %d/%d", location.segment, location.sector);
|
| 332 |
|
|
} else {
|
| 333 |
|
|
TRACEx2(6, "passing segment %d/%d", location.segment, location.sector);
|
| 334 |
|
|
}
|
| 335 |
|
|
}
|
| 336 |
|
|
TRACE_EXIT;
|
| 337 |
|
|
return result;
|
| 338 |
|
|
}
|
| 339 |
|
|
|
| 340 |
|
|
static int logical_forward(void)
|
| 341 |
|
|
{
|
| 342 |
|
|
tape_running = 1;
|
| 343 |
|
|
return ftape_command(QIC_LOGICAL_FORWARD);
|
| 344 |
|
|
}
|
| 345 |
|
|
|
| 346 |
|
|
static int stop_tape(int *pstatus)
|
| 347 |
|
|
{
|
| 348 |
|
|
TRACE_FUN(5, "stop_tape");
|
| 349 |
|
|
int retry = 0;
|
| 350 |
|
|
int result;
|
| 351 |
|
|
|
| 352 |
|
|
do {
|
| 353 |
|
|
result = ftape_command_wait(QIC_STOP_TAPE, timeout.stop, pstatus);
|
| 354 |
|
|
if (result == 0) {
|
| 355 |
|
|
if ((*pstatus & QIC_STATUS_READY) == 0) {
|
| 356 |
|
|
result = -EIO;
|
| 357 |
|
|
} else {
|
| 358 |
|
|
tape_running = 0;
|
| 359 |
|
|
}
|
| 360 |
|
|
}
|
| 361 |
|
|
} while (result < 0 && ++retry <= 3);
|
| 362 |
|
|
if (result < 0) {
|
| 363 |
|
|
TRACE(1, "failed ! (fatal)");
|
| 364 |
|
|
}
|
| 365 |
|
|
TRACE_EXIT;
|
| 366 |
|
|
return result;
|
| 367 |
|
|
}
|
| 368 |
|
|
|
| 369 |
|
|
int ftape_dumb_stop(void)
|
| 370 |
|
|
{
|
| 371 |
|
|
TRACE_FUN(5, "ftape_dumb_stop");
|
| 372 |
|
|
int result;
|
| 373 |
|
|
int status;
|
| 374 |
|
|
|
| 375 |
|
|
/* Abort current fdc operation if it's busy (probably read
|
| 376 |
|
|
* or write operation pending) with a reset.
|
| 377 |
|
|
*/
|
| 378 |
|
|
result = fdc_ready_wait(100 /* usec */ );
|
| 379 |
|
|
if (result < 0) {
|
| 380 |
|
|
TRACE(1, "aborting fdc operation");
|
| 381 |
|
|
fdc_reset();
|
| 382 |
|
|
}
|
| 383 |
|
|
/* Reading id's after the last segment on a track may fail
|
| 384 |
|
|
* but eventually the drive will become ready (logical eot).
|
| 385 |
|
|
*/
|
| 386 |
|
|
result = ftape_report_drive_status(&status);
|
| 387 |
|
|
location.known = 0;
|
| 388 |
|
|
do {
|
| 389 |
|
|
if (result == 0 && status & QIC_STATUS_READY) {
|
| 390 |
|
|
/* Tape is not running any more.
|
| 391 |
|
|
*/
|
| 392 |
|
|
TRACE(5, "tape already halted");
|
| 393 |
|
|
check_bot_eot(status);
|
| 394 |
|
|
tape_running = 0;
|
| 395 |
|
|
} else if (tape_running) {
|
| 396 |
|
|
/* Tape is (was) still moving.
|
| 397 |
|
|
*/
|
| 398 |
|
|
#ifdef TESTING
|
| 399 |
|
|
ftape_read_id();
|
| 400 |
|
|
#endif
|
| 401 |
|
|
result = stop_tape(&status);
|
| 402 |
|
|
} else {
|
| 403 |
|
|
/* Tape not yet ready but stopped.
|
| 404 |
|
|
*/
|
| 405 |
|
|
result = ftape_ready_wait(timeout.pause, &status);
|
| 406 |
|
|
}
|
| 407 |
|
|
} while (tape_running);
|
| 408 |
|
|
#ifndef TESTING
|
| 409 |
|
|
location.known = 0;
|
| 410 |
|
|
#endif
|
| 411 |
|
|
TRACE_EXIT;
|
| 412 |
|
|
return result;
|
| 413 |
|
|
}
|
| 414 |
|
|
|
| 415 |
|
|
/* Wait until runner has finished tail buffer.
|
| 416 |
|
|
*/
|
| 417 |
|
|
int wait_segment(buffer_state_enum state)
|
| 418 |
|
|
{
|
| 419 |
|
|
TRACE_FUN(5, "wait_segment");
|
| 420 |
|
|
int result = 0;
|
| 421 |
|
|
|
| 422 |
|
|
while (buffer[tail].status == state) {
|
| 423 |
|
|
/* First buffer still being worked on, wait up to timeout.
|
| 424 |
|
|
*/
|
| 425 |
|
|
result = fdc_interrupt_wait(50 * SECOND);
|
| 426 |
|
|
if (result < 0) {
|
| 427 |
|
|
if (result != -EINTR) {
|
| 428 |
|
|
TRACE(1, "fdc_interrupt_wait failed");
|
| 429 |
|
|
result = -ETIME;
|
| 430 |
|
|
}
|
| 431 |
|
|
break;
|
| 432 |
|
|
}
|
| 433 |
|
|
if (fdc_setup_error) {
|
| 434 |
|
|
TRACE(1, "setup error");
|
| 435 |
|
|
/* recover... */
|
| 436 |
|
|
result = -EIO;
|
| 437 |
|
|
break;
|
| 438 |
|
|
}
|
| 439 |
|
|
}
|
| 440 |
|
|
TRACE_EXIT;
|
| 441 |
|
|
return result;
|
| 442 |
|
|
}
|
| 443 |
|
|
|
| 444 |
|
|
/* forward */ static int seek_forward(int segment_id);
|
| 445 |
|
|
|
| 446 |
|
|
int fast_seek(int count, int reverse)
|
| 447 |
|
|
{
|
| 448 |
|
|
TRACE_FUN(5, "fast_seek");
|
| 449 |
|
|
int result = 0;
|
| 450 |
|
|
int status;
|
| 451 |
|
|
|
| 452 |
|
|
if (count > 0) {
|
| 453 |
|
|
/* If positioned at begin or end of tape, fast seeking needs
|
| 454 |
|
|
* special treatment.
|
| 455 |
|
|
* Starting from logical bot needs a (slow) seek to the first
|
| 456 |
|
|
* segment before the high speed seek. Most drives do this
|
| 457 |
|
|
* automatically but some older don't, so we treat them
|
| 458 |
|
|
* all the same.
|
| 459 |
|
|
* Starting from logical eot is even more difficult because
|
| 460 |
|
|
* we cannot (slow) reverse seek to the last segment.
|
| 461 |
|
|
* TO BE IMPLEMENTED.
|
| 462 |
|
|
*/
|
| 463 |
|
|
inhibit_correction = 0;
|
| 464 |
|
|
if (location.known &&
|
| 465 |
|
|
((location.bot && !reverse) ||
|
| 466 |
|
|
(location.eot && reverse))) {
|
| 467 |
|
|
if (!reverse) {
|
| 468 |
|
|
/* (slow) skip to first segment on a track
|
| 469 |
|
|
*/
|
| 470 |
|
|
seek_forward(location.track * segments_per_track);
|
| 471 |
|
|
--count;
|
| 472 |
|
|
} else {
|
| 473 |
|
|
/* When seeking backwards from end-of-tape the number
|
| 474 |
|
|
* of erased gaps found seems to be higher than expected.
|
| 475 |
|
|
* Therefor the drive must skip some more segments than
|
| 476 |
|
|
* calculated, but we don't know how many.
|
| 477 |
|
|
* Thus we will prevent the re-calculation of offset
|
| 478 |
|
|
* and overshoot when seeking backwards.
|
| 479 |
|
|
*/
|
| 480 |
|
|
inhibit_correction = 1;
|
| 481 |
|
|
count += 3; /* best guess */
|
| 482 |
|
|
}
|
| 483 |
|
|
}
|
| 484 |
|
|
} else {
|
| 485 |
|
|
TRACEx1(5, "warning: zero or negative count: %d", count);
|
| 486 |
|
|
}
|
| 487 |
|
|
if (count > 0) {
|
| 488 |
|
|
int i;
|
| 489 |
|
|
int nibbles = count > 255 ? 3 : 2;
|
| 490 |
|
|
|
| 491 |
|
|
if (count > 4095) {
|
| 492 |
|
|
TRACE(4, "skipping clipped at 4095 segment");
|
| 493 |
|
|
count = 4095;
|
| 494 |
|
|
}
|
| 495 |
|
|
/* Issue this tape command first. */
|
| 496 |
|
|
if (!reverse) {
|
| 497 |
|
|
TRACEx1(4, "skipping %d segment(s)", count);
|
| 498 |
|
|
result = ftape_command(nibbles == 3 ?
|
| 499 |
|
|
QIC_SKIP_EXTENDED_FORWARD : QIC_SKIP_FORWARD);
|
| 500 |
|
|
} else {
|
| 501 |
|
|
TRACEx1(4, "backing up %d segment(s)", count);
|
| 502 |
|
|
result = ftape_command(nibbles == 3 ?
|
| 503 |
|
|
QIC_SKIP_EXTENDED_REVERSE : QIC_SKIP_REVERSE);
|
| 504 |
|
|
}
|
| 505 |
|
|
if (result < 0) {
|
| 506 |
|
|
TRACE(4, "Skip command failed");
|
| 507 |
|
|
} else {
|
| 508 |
|
|
--count; /* 0 means one gap etc. */
|
| 509 |
|
|
for (i = 0; i < nibbles; ++i) {
|
| 510 |
|
|
if (result >= 0) {
|
| 511 |
|
|
result = ftape_parameter(count & 15);
|
| 512 |
|
|
count /= 16;
|
| 513 |
|
|
}
|
| 514 |
|
|
}
|
| 515 |
|
|
result = ftape_ready_wait(timeout.rewind, &status);
|
| 516 |
|
|
if (result >= 0) {
|
| 517 |
|
|
tape_running = 0;
|
| 518 |
|
|
}
|
| 519 |
|
|
}
|
| 520 |
|
|
}
|
| 521 |
|
|
TRACE_EXIT;
|
| 522 |
|
|
return result;
|
| 523 |
|
|
}
|
| 524 |
|
|
|
| 525 |
|
|
static int validate(int id)
|
| 526 |
|
|
{
|
| 527 |
|
|
/* Check to see if position found is off-track as reported once.
|
| 528 |
|
|
* Because all tracks in one direction lie next to each other,
|
| 529 |
|
|
* if off-track the error will be approximately 2 * segments_per_track.
|
| 530 |
|
|
*/
|
| 531 |
|
|
if (location.track == -1) {
|
| 532 |
|
|
return 1; /* unforeseen situation, don't generate error */
|
| 533 |
|
|
} else {
|
| 534 |
|
|
/* Use margin of segments_per_track on both sides because ftape
|
| 535 |
|
|
* needs some margin and the error we're looking for is much larger !
|
| 536 |
|
|
*/
|
| 537 |
|
|
int lo = (location.track - 1) * segments_per_track;
|
| 538 |
|
|
int hi = (location.track + 2) * segments_per_track;
|
| 539 |
|
|
|
| 540 |
|
|
return (id >= lo && id < hi);
|
| 541 |
|
|
}
|
| 542 |
|
|
}
|
| 543 |
|
|
|
| 544 |
|
|
static int seek_forward(int segment_id)
|
| 545 |
|
|
{
|
| 546 |
|
|
TRACE_FUN(5, "seek_forward");
|
| 547 |
|
|
int failures = 0;
|
| 548 |
|
|
int result = 0;
|
| 549 |
|
|
int count;
|
| 550 |
|
|
static int margin = 1; /* fixed: stop this before target */
|
| 551 |
|
|
static int overshoot = 1;
|
| 552 |
|
|
static int min_count = 8;
|
| 553 |
|
|
int expected = -1;
|
| 554 |
|
|
int target = segment_id - margin;
|
| 555 |
|
|
int fast_seeking;
|
| 556 |
|
|
|
| 557 |
|
|
if (!location.known) {
|
| 558 |
|
|
TRACE(1, "fatal: cannot seek from unknown location");
|
| 559 |
|
|
result = -EIO;
|
| 560 |
|
|
} else if (!validate(segment_id)) {
|
| 561 |
|
|
TRACE(1, "fatal: head off track (bad hardware?)");
|
| 562 |
|
|
ftape_sleep(1 * SECOND);
|
| 563 |
|
|
ftape_failure = 1;
|
| 564 |
|
|
result = -EIO;
|
| 565 |
|
|
} else {
|
| 566 |
|
|
int prev_segment = location.segment;
|
| 567 |
|
|
|
| 568 |
|
|
TRACEx4(4, "from %d/%d to %d/0 - %d", location.segment,
|
| 569 |
|
|
location.sector, segment_id, margin);
|
| 570 |
|
|
count = target - location.segment - overshoot;
|
| 571 |
|
|
fast_seeking = (count > min_count + (location.bot ? 1 : 0));
|
| 572 |
|
|
if (fast_seeking) {
|
| 573 |
|
|
TRACEx1(5, "fast skipping %d segments", count);
|
| 574 |
|
|
expected = segment_id - margin;
|
| 575 |
|
|
fast_seek(count, 0);
|
| 576 |
|
|
}
|
| 577 |
|
|
if (!tape_running) {
|
| 578 |
|
|
logical_forward();
|
| 579 |
|
|
}
|
| 580 |
|
|
while (location.segment < segment_id) {
|
| 581 |
|
|
/* This requires at least one sector in a (bad) segment to
|
| 582 |
|
|
* have a valid and readable sector id !
|
| 583 |
|
|
* It looks like this is not guaranteed, so we must try
|
| 584 |
|
|
* to find a way to skip an EMPTY_SEGMENT. !!! FIXME !!!
|
| 585 |
|
|
*/
|
| 586 |
|
|
if (ftape_read_id() < 0 || !location.known) {
|
| 587 |
|
|
location.known = 0;
|
| 588 |
|
|
if (!tape_running || ++failures > SECTORS_PER_SEGMENT ||
|
| 589 |
|
|
(current->signal & _DONT_BLOCK)) {
|
| 590 |
|
|
TRACE(1, "read_id failed completely");
|
| 591 |
|
|
result = -EIO;
|
| 592 |
|
|
break;
|
| 593 |
|
|
} else {
|
| 594 |
|
|
TRACEx1(5, "read_id failed, retry (%d)", failures);
|
| 595 |
|
|
}
|
| 596 |
|
|
} else if (fast_seeking) {
|
| 597 |
|
|
TRACEx4(4, "ended at %d/%d (%d,%d)", location.segment,
|
| 598 |
|
|
location.sector, overshoot, inhibit_correction);
|
| 599 |
|
|
if (!inhibit_correction &&
|
| 600 |
|
|
(location.segment < expected ||
|
| 601 |
|
|
location.segment > expected + margin)) {
|
| 602 |
|
|
int error = location.segment - expected;
|
| 603 |
|
|
TRACEx2(4, "adjusting overshoot from %d to %d",
|
| 604 |
|
|
overshoot, overshoot + error);
|
| 605 |
|
|
overshoot += error;
|
| 606 |
|
|
/* All overshoots have the same direction, so it should
|
| 607 |
|
|
* never become negative, but who knows.
|
| 608 |
|
|
*/
|
| 609 |
|
|
if (overshoot < -5 || overshoot > 10) {
|
| 610 |
|
|
if (overshoot < 0) {
|
| 611 |
|
|
overshoot = -5; /* keep sane value */
|
| 612 |
|
|
} else {
|
| 613 |
|
|
overshoot = 10; /* keep sane value */
|
| 614 |
|
|
}
|
| 615 |
|
|
TRACEx1(4, "clipped overshoot to %d", overshoot);
|
| 616 |
|
|
}
|
| 617 |
|
|
}
|
| 618 |
|
|
fast_seeking = 0;
|
| 619 |
|
|
}
|
| 620 |
|
|
if (location.known) {
|
| 621 |
|
|
if (location.segment > prev_segment + 1) {
|
| 622 |
|
|
TRACEx1(4, "missed segment %d while skipping", prev_segment + 1);
|
| 623 |
|
|
}
|
| 624 |
|
|
prev_segment = location.segment;
|
| 625 |
|
|
}
|
| 626 |
|
|
}
|
| 627 |
|
|
if (location.segment > segment_id) {
|
| 628 |
|
|
TRACEx2(4, "failed: skip ended at segment %d/%d",
|
| 629 |
|
|
location.segment, location.sector);
|
| 630 |
|
|
result = -EIO;
|
| 631 |
|
|
}
|
| 632 |
|
|
}
|
| 633 |
|
|
TRACE_EXIT;
|
| 634 |
|
|
return result;
|
| 635 |
|
|
}
|
| 636 |
|
|
|
| 637 |
|
|
static int skip_reverse(int segment_id, int *pstatus)
|
| 638 |
|
|
{
|
| 639 |
|
|
TRACE_FUN(5, "skip_reverse");
|
| 640 |
|
|
int result = 0;
|
| 641 |
|
|
int failures = 0;
|
| 642 |
|
|
static int overshoot = 1;
|
| 643 |
|
|
static int min_rewind = 2; /* 1 + overshoot */
|
| 644 |
|
|
static const int margin = 1; /* stop this before target */
|
| 645 |
|
|
int expected = 0;
|
| 646 |
|
|
int count;
|
| 647 |
|
|
int short_seek;
|
| 648 |
|
|
int target = segment_id - margin;
|
| 649 |
|
|
|
| 650 |
|
|
if (location.known && !validate(segment_id)) {
|
| 651 |
|
|
TRACE(1, "fatal: head off track (bad hardware?)");
|
| 652 |
|
|
ftape_sleep(1 * SECOND);
|
| 653 |
|
|
ftape_failure = 1;
|
| 654 |
|
|
result = -EIO;
|
| 655 |
|
|
} else
|
| 656 |
|
|
do {
|
| 657 |
|
|
if (!location.known) {
|
| 658 |
|
|
TRACE(-1, "warning: location not known");
|
| 659 |
|
|
}
|
| 660 |
|
|
TRACEx4(4, "from %d/%d to %d/0 - %d",
|
| 661 |
|
|
location.segment, location.sector, segment_id, margin);
|
| 662 |
|
|
/* min_rewind == 1 + overshoot_when_doing_minimum_rewind
|
| 663 |
|
|
* overshoot == overshoot_when_doing_larger_rewind
|
| 664 |
|
|
* Initially min_rewind == 1 + overshoot, optimization
|
| 665 |
|
|
* of both values will be done separately.
|
| 666 |
|
|
* overshoot and min_rewind can be negative as both are
|
| 667 |
|
|
* sums of three components:
|
| 668 |
|
|
* any_overshoot == rewind_overshoot - stop_overshoot - start_overshoot
|
| 669 |
|
|
*/
|
| 670 |
|
|
if (location.segment - target - (min_rewind - 1) < 1) {
|
| 671 |
|
|
short_seek = 1;
|
| 672 |
|
|
} else {
|
| 673 |
|
|
count = location.segment - target - overshoot;
|
| 674 |
|
|
short_seek = (count < 1);
|
| 675 |
|
|
}
|
| 676 |
|
|
if (short_seek) {
|
| 677 |
|
|
count = 1; /* do shortest rewind */
|
| 678 |
|
|
expected = location.segment - min_rewind;
|
| 679 |
|
|
if (expected / segments_per_track != location.track) {
|
| 680 |
|
|
expected = location.track * segments_per_track;
|
| 681 |
|
|
}
|
| 682 |
|
|
} else {
|
| 683 |
|
|
expected = target;
|
| 684 |
|
|
}
|
| 685 |
|
|
fast_seek(count, 1);
|
| 686 |
|
|
logical_forward();
|
| 687 |
|
|
result = ftape_read_id();
|
| 688 |
|
|
if (result == 0 && location.known) {
|
| 689 |
|
|
TRACEx5(4, "ended at %d/%d (%d,%d,%d)", location.segment,
|
| 690 |
|
|
location.sector, min_rewind, overshoot, inhibit_correction);
|
| 691 |
|
|
if (!inhibit_correction &&
|
| 692 |
|
|
(location.segment < expected ||
|
| 693 |
|
|
location.segment > expected + margin)) {
|
| 694 |
|
|
int error = expected - location.segment;
|
| 695 |
|
|
if (short_seek) {
|
| 696 |
|
|
TRACEx2(4, "adjusting min_rewind from %d to %d",
|
| 697 |
|
|
min_rewind, min_rewind + error);
|
| 698 |
|
|
min_rewind += error;
|
| 699 |
|
|
if (min_rewind < -5) { /* is this right ? FIXME ! */
|
| 700 |
|
|
min_rewind = -5; /* keep sane value */
|
| 701 |
|
|
TRACEx1(4, "clipped min_rewind to %d", min_rewind);
|
| 702 |
|
|
}
|
| 703 |
|
|
} else {
|
| 704 |
|
|
TRACEx2(4, "adjusting overshoot from %d to %d",
|
| 705 |
|
|
overshoot, overshoot + error);
|
| 706 |
|
|
overshoot += error;
|
| 707 |
|
|
if (overshoot < -5 || overshoot > 10) {
|
| 708 |
|
|
if (overshoot < 0) {
|
| 709 |
|
|
overshoot = -5; /* keep sane value */
|
| 710 |
|
|
} else {
|
| 711 |
|
|
overshoot = 10; /* keep sane value */
|
| 712 |
|
|
}
|
| 713 |
|
|
TRACEx1(4, "clipped overshoot to %d", overshoot);
|
| 714 |
|
|
}
|
| 715 |
|
|
}
|
| 716 |
|
|
}
|
| 717 |
|
|
} else {
|
| 718 |
|
|
if ((!tape_running && !location.known) ||
|
| 719 |
|
|
++failures > SECTORS_PER_SEGMENT) {
|
| 720 |
|
|
TRACE(1, "read_id failed completely");
|
| 721 |
|
|
result = -EIO;
|
| 722 |
|
|
break;
|
| 723 |
|
|
} else {
|
| 724 |
|
|
TRACEx1(5, "ftape_read_id failed, retry (%d)", failures);
|
| 725 |
|
|
}
|
| 726 |
|
|
result = ftape_report_drive_status(pstatus);
|
| 727 |
|
|
if (result < 0) {
|
| 728 |
|
|
TRACEi(1, "ftape_report_drive_status failed with code", result);
|
| 729 |
|
|
break;
|
| 730 |
|
|
}
|
| 731 |
|
|
}
|
| 732 |
|
|
} while (location.segment > segment_id &&
|
| 733 |
|
|
(current->signal & _DONT_BLOCK) == 0);
|
| 734 |
|
|
if (location.known) {
|
| 735 |
|
|
TRACEx2(4, "current location: %d/%d", location.segment, location.sector);
|
| 736 |
|
|
}
|
| 737 |
|
|
TRACE_EXIT;
|
| 738 |
|
|
return result;
|
| 739 |
|
|
}
|
| 740 |
|
|
|
| 741 |
|
|
static int determine_position(void)
|
| 742 |
|
|
{
|
| 743 |
|
|
TRACE_FUN(5, "determine_position");
|
| 744 |
|
|
int retry = 0;
|
| 745 |
|
|
int fatal = 0;
|
| 746 |
|
|
int status;
|
| 747 |
|
|
int result;
|
| 748 |
|
|
|
| 749 |
|
|
if (!tape_running) {
|
| 750 |
|
|
/* This should only happen if tape is stopped by isr.
|
| 751 |
|
|
*/
|
| 752 |
|
|
TRACE(5, "waiting for tape stop");
|
| 753 |
|
|
result = ftape_ready_wait(timeout.pause, &status);
|
| 754 |
|
|
if (result < 0) {
|
| 755 |
|
|
TRACE(5, "drive still running (fatal)");
|
| 756 |
|
|
tape_running = 1; /* ? */
|
| 757 |
|
|
}
|
| 758 |
|
|
} else {
|
| 759 |
|
|
ftape_report_drive_status(&status);
|
| 760 |
|
|
}
|
| 761 |
|
|
if (status & QIC_STATUS_READY) {
|
| 762 |
|
|
/* Drive must be ready to check error state !
|
| 763 |
|
|
*/
|
| 764 |
|
|
TRACE(5, "drive is ready");
|
| 765 |
|
|
if (status & QIC_STATUS_ERROR) {
|
| 766 |
|
|
int error;
|
| 767 |
|
|
int command;
|
| 768 |
|
|
|
| 769 |
|
|
/* Report and clear error state, try to continue.
|
| 770 |
|
|
*/
|
| 771 |
|
|
TRACE(5, "error status set");
|
| 772 |
|
|
ftape_report_error(&error, &command, 1);
|
| 773 |
|
|
ftape_ready_wait(timeout.reset, &status);
|
| 774 |
|
|
tape_running = 0; /* ? */
|
| 775 |
|
|
}
|
| 776 |
|
|
if (check_bot_eot(status)) {
|
| 777 |
|
|
if (location.bot) {
|
| 778 |
|
|
if ((status & QIC_STATUS_READY) == 0) {
|
| 779 |
|
|
/* tape moving away from bot/eot, let's see if we
|
| 780 |
|
|
* can catch up with the first segment on this track.
|
| 781 |
|
|
*/
|
| 782 |
|
|
} else {
|
| 783 |
|
|
TRACE(5, "start tape from logical bot");
|
| 784 |
|
|
logical_forward(); /* start moving */
|
| 785 |
|
|
}
|
| 786 |
|
|
} else {
|
| 787 |
|
|
if ((status & QIC_STATUS_READY) == 0) {
|
| 788 |
|
|
TRACE(4, "waiting for logical end of track");
|
| 789 |
|
|
result = ftape_ready_wait(timeout.reset, &status);
|
| 790 |
|
|
/* error handling needed ? */
|
| 791 |
|
|
} else {
|
| 792 |
|
|
TRACE(4, "tape at logical end of track");
|
| 793 |
|
|
}
|
| 794 |
|
|
}
|
| 795 |
|
|
} else {
|
| 796 |
|
|
TRACE(5, "start tape");
|
| 797 |
|
|
logical_forward(); /* start moving */
|
| 798 |
|
|
location.known = 0; /* not cleared by logical forward ! */
|
| 799 |
|
|
}
|
| 800 |
|
|
}
|
| 801 |
|
|
if (!location.known) {
|
| 802 |
|
|
/* tape should be moving now, start reading id's
|
| 803 |
|
|
*/
|
| 804 |
|
|
TRACE(5, "location unknown");
|
| 805 |
|
|
do {
|
| 806 |
|
|
result = ftape_read_id();
|
| 807 |
|
|
if (result < 0) {
|
| 808 |
|
|
/* read-id somehow failed, tape may have reached end
|
| 809 |
|
|
* or some other error happened.
|
| 810 |
|
|
*/
|
| 811 |
|
|
TRACE(5, "read-id failed");
|
| 812 |
|
|
ftape_report_drive_status(&status);
|
| 813 |
|
|
if (status & QIC_STATUS_READY) {
|
| 814 |
|
|
tape_running = 0;
|
| 815 |
|
|
TRACEx1(4, "tape stopped for unknown reason ! status = 0x%02x",
|
| 816 |
|
|
status);
|
| 817 |
|
|
if (status & QIC_STATUS_ERROR) {
|
| 818 |
|
|
fatal = 1;
|
| 819 |
|
|
} else {
|
| 820 |
|
|
if (check_bot_eot(status)) {
|
| 821 |
|
|
result = 0;
|
| 822 |
|
|
} else {
|
| 823 |
|
|
fatal = 1; /* oops, tape stopped but not at end ! */
|
| 824 |
|
|
}
|
| 825 |
|
|
}
|
| 826 |
|
|
}
|
| 827 |
|
|
result = -EIO;
|
| 828 |
|
|
}
|
| 829 |
|
|
} while (result < 0 && !fatal && ++retry < SECTORS_PER_SEGMENT);
|
| 830 |
|
|
} else {
|
| 831 |
|
|
result = 0;
|
| 832 |
|
|
}
|
| 833 |
|
|
TRACEx1(5, "tape is positioned at segment %d", location.segment);
|
| 834 |
|
|
TRACE_EXIT;
|
| 835 |
|
|
return result;
|
| 836 |
|
|
}
|
| 837 |
|
|
|
| 838 |
|
|
/* Get the tape running and position it just before the
|
| 839 |
|
|
* requested segment.
|
| 840 |
|
|
* Seek tape-track and reposition as needed.
|
| 841 |
|
|
*/
|
| 842 |
|
|
int ftape_start_tape(int segment_id, int sector_offset)
|
| 843 |
|
|
{
|
| 844 |
|
|
TRACE_FUN(5, "ftape_start_tape");
|
| 845 |
|
|
int track = segment_id / segments_per_track;
|
| 846 |
|
|
int result = -EIO;
|
| 847 |
|
|
int status;
|
| 848 |
|
|
static int last_segment = -1;
|
| 849 |
|
|
static int bad_bus_timing = 0;
|
| 850 |
|
|
/* number of segments passing the head between starting the tape
|
| 851 |
|
|
* and being able to access the first sector.
|
| 852 |
|
|
*/
|
| 853 |
|
|
static int start_offset = 1;
|
| 854 |
|
|
int retry = 0;
|
| 855 |
|
|
|
| 856 |
|
|
/* If sector_offset > 0, seek into wanted segment instead of
|
| 857 |
|
|
* into previous.
|
| 858 |
|
|
* This allows error recovery if a part of the segment is bad
|
| 859 |
|
|
* (erased) causing the tape drive to generate an index pulse
|
| 860 |
|
|
* thus causing a no-data error before the requested sector
|
| 861 |
|
|
* is reached.
|
| 862 |
|
|
*/
|
| 863 |
|
|
tape_running = 0;
|
| 864 |
|
|
TRACEx3(4, "target segment: %d/%d%s", segment_id, sector_offset,
|
| 865 |
|
|
buffer[head].retry > 0 ? " retry" : "");
|
| 866 |
|
|
if (buffer[head].retry > 0) { /* this is a retry */
|
| 867 |
|
|
if (!bad_bus_timing && ftape_data_rate == 1 &&
|
| 868 |
|
|
history.overrun_errors - overrun_count_offset >= 8) {
|
| 869 |
|
|
ftape_set_data_rate(ftape_data_rate + 1);
|
| 870 |
|
|
bad_bus_timing = 1;
|
| 871 |
|
|
TRACE(2, "reduced datarate because of excessive overrun errors");
|
| 872 |
|
|
}
|
| 873 |
|
|
}
|
| 874 |
|
|
last_segment = segment_id;
|
| 875 |
|
|
if (location.track != track || (might_be_off_track &&
|
| 876 |
|
|
buffer[head].retry == 0)) {
|
| 877 |
|
|
/* current track unknown or not equal to destination
|
| 878 |
|
|
*/
|
| 879 |
|
|
ftape_ready_wait(timeout.seek, &status);
|
| 880 |
|
|
ftape_seek_head_to_track(track);
|
| 881 |
|
|
overrun_count_offset = history.overrun_errors;
|
| 882 |
|
|
}
|
| 883 |
|
|
do {
|
| 884 |
|
|
if (!location.known) {
|
| 885 |
|
|
determine_position();
|
| 886 |
|
|
}
|
| 887 |
|
|
/* Check if we are able to catch the requested segment in time.
|
| 888 |
|
|
*/
|
| 889 |
|
|
if (location.known && location.segment >= segment_id -
|
| 890 |
|
|
((tape_running || location.bot) ? 0 : start_offset)) {
|
| 891 |
|
|
/* Too far ahead (in or past target segment).
|
| 892 |
|
|
*/
|
| 893 |
|
|
if (tape_running) {
|
| 894 |
|
|
result = stop_tape(&status);
|
| 895 |
|
|
if (result < 0) {
|
| 896 |
|
|
TRACEi(1, "stop tape failed with code", result);
|
| 897 |
|
|
break;
|
| 898 |
|
|
}
|
| 899 |
|
|
TRACE(5, "tape stopped");
|
| 900 |
|
|
tape_running = 0;
|
| 901 |
|
|
}
|
| 902 |
|
|
TRACE(5, "repositioning");
|
| 903 |
|
|
++history.rewinds;
|
| 904 |
|
|
if (segment_id % segments_per_track < start_offset) {
|
| 905 |
|
|
/* If seeking to first segments on track better do a complete
|
| 906 |
|
|
* rewind to logical begin of track to get a more steady tape
|
| 907 |
|
|
* motion.
|
| 908 |
|
|
*/
|
| 909 |
|
|
result = ftape_command_wait((location.track & 1) ?
|
| 910 |
|
|
QIC_PHYSICAL_FORWARD :
|
| 911 |
|
|
QIC_PHYSICAL_REVERSE,
|
| 912 |
|
|
timeout.rewind, &status);
|
| 913 |
|
|
check_bot_eot(status); /* update location */
|
| 914 |
|
|
} else {
|
| 915 |
|
|
result = skip_reverse(segment_id - start_offset, &status);
|
| 916 |
|
|
}
|
| 917 |
|
|
}
|
| 918 |
|
|
if (!location.known) {
|
| 919 |
|
|
TRACE(-1, "panic: location not known");
|
| 920 |
|
|
result = -EIO;
|
| 921 |
|
|
if ((current->signal & _DONT_BLOCK) || ftape_failure) {
|
| 922 |
|
|
break;
|
| 923 |
|
|
} else {
|
| 924 |
|
|
continue;
|
| 925 |
|
|
}
|
| 926 |
|
|
}
|
| 927 |
|
|
TRACEx2(4, "current segment: %d/%d", location.segment, location.sector);
|
| 928 |
|
|
/* We're on the right track somewhere before the wanted segment.
|
| 929 |
|
|
* Start tape movement if needed and skip to just before or inside
|
| 930 |
|
|
* the requested segment. Keep tape running.
|
| 931 |
|
|
*/
|
| 932 |
|
|
result = 0;
|
| 933 |
|
|
if (location.segment < segment_id -
|
| 934 |
|
|
((tape_running || location.bot) ? 0 : start_offset)) {
|
| 935 |
|
|
if (sector_offset > 0) {
|
| 936 |
|
|
result = seek_forward(segment_id);
|
| 937 |
|
|
} else {
|
| 938 |
|
|
result = seek_forward(segment_id - 1);
|
| 939 |
|
|
}
|
| 940 |
|
|
}
|
| 941 |
|
|
if (result == 0 &&
|
| 942 |
|
|
location.segment != segment_id - (sector_offset > 0 ? 0 : 1)) {
|
| 943 |
|
|
result = -EIO;
|
| 944 |
|
|
}
|
| 945 |
|
|
} while (result < 0 && !ftape_failure &&
|
| 946 |
|
|
(current->signal & _DONT_BLOCK) == 0 &&
|
| 947 |
|
|
++retry <= 5);
|
| 948 |
|
|
if (result < 0) {
|
| 949 |
|
|
TRACE(1, "failed to reposition");
|
| 950 |
|
|
}
|
| 951 |
|
|
TRACE_EXIT;
|
| 952 |
|
|
return result;
|
| 953 |
|
|
}
|
