git.oblomov.eu Git - linux-2.6/blob - drivers/char/ftape/lowlevel/ftape-write.c

   1 /*
   2  *      Copyright (C) 1993-1995 Bas Laarhoven,
   3  *                (C) 1996-1997 Claus-Justus Heine.
   4
   5  This program is free software; you can redistribute it and/or modify
   6  it under the terms of the GNU General Public License as published by
   7  the Free Software Foundation; either version 2, or (at your option)
   8  any later version.
   9
  10  This program is distributed in the hope that it will be useful,
  11  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  GNU General Public License for more details.
  14
  15  You should have received a copy of the GNU General Public License
  16  along with this program; see the file COPYING.  If not, write to
  17  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  18
  19  *
  20  * $Source: /homes/cvs/ftape-stacked/ftape/lowlevel/ftape-write.c,v $
  21  * $Revision: 1.3.4.1 $
  22  * $Date: 1997/11/14 18:07:04 $
  23  *
  24  *      This file contains the writing code
  25  *      for the QIC-117 floppy-tape driver for Linux.
  26  */
  27
  28 #include <linux/string.h>
  29 #include <linux/errno.h>
  30 #include <linux/mm.h>
  31
  32 #include <linux/ftape.h>
  33 #include <linux/qic117.h>
  34 #include "../lowlevel/ftape-tracing.h"
  35 #include "../lowlevel/ftape-write.h"
  36 #include "../lowlevel/ftape-read.h"
  37 #include "../lowlevel/ftape-io.h"
  38 #include "../lowlevel/ftape-ctl.h"
  39 #include "../lowlevel/ftape-rw.h"
  40 #include "../lowlevel/ftape-ecc.h"
  41 #include "../lowlevel/ftape-bsm.h"
  42 #include "../lowlevel/fdc-isr.h"
  43
  44 /*      Global vars.
  45  */
  46
  47 /*      Local vars.
  48  */
  49 static int last_write_failed;
  50
  51 void ftape_zap_write_buffers(void)
  52 {
  53         int i;
  54
  55         for (i = 0; i < ft_nr_buffers; ++i) {
  56                 ft_buffer[i]->status = done;
  57         }
  58         ftape_reset_buffer();
  59 }
  60
  61 static int copy_and_gen_ecc(void *destination,
  62                             const void *source,
  63                             const SectorMap bad_sector_map)
  64 {
  65         int result;
  66         struct memory_segment mseg;
  67         int bads = count_ones(bad_sector_map);
  68         TRACE_FUN(ft_t_any);
  69
  70         if (bads > 0) {
  71                 TRACE(ft_t_noise, "bad sectors in map: %d", bads);
  72         }
  73         if (bads + 3 >= FT_SECTORS_PER_SEGMENT) {
  74                 TRACE(ft_t_noise, "empty segment");
  75                 mseg.blocks = 0; /* skip entire segment */
  76                 result = 0;      /* nothing written */
  77         } else {
  78                 mseg.blocks = FT_SECTORS_PER_SEGMENT - bads;
  79                 mseg.data = destination;
  80                 memcpy(mseg.data, source, (mseg.blocks - 3) * FT_SECTOR_SIZE);
  81                 result = ftape_ecc_set_segment_parity(&mseg);
  82                 if (result < 0) {
  83                         TRACE(ft_t_err, "ecc_set_segment_parity failed");
  84                 } else {
  85                         result = (mseg.blocks - 3) * FT_SECTOR_SIZE;
  86                 }
  87         }
  88         TRACE_EXIT result;
  89 }
  90
  91
  92 int ftape_start_writing(const ft_write_mode_t mode)
  93 {
  94         buffer_struct *head = ftape_get_buffer(ft_queue_head);
  95         int segment_id = head->segment_id;
  96         int result;
  97         buffer_state_enum wanted_state = (mode == FT_WR_DELETE
  98                                           ? deleting
  99                                           : writing);
 100         TRACE_FUN(ft_t_flow);
 101
 102         if ((ft_driver_state != wanted_state) || head->status != waiting) {
 103                 TRACE_EXIT 0;
 104         }
 105         ftape_setup_new_segment(head, segment_id, 1);
 106         if (mode == FT_WR_SINGLE) {
 107                 /* stop tape instead of pause */
 108                 head->next_segment = 0;
 109         }
 110         ftape_calc_next_cluster(head); /* prepare */
 111         head->status = ft_driver_state; /* either writing or deleting */
 112         if (ft_runner_status == idle) {
 113                 TRACE(ft_t_noise,
 114                       "starting runner for segment %d", segment_id);
 115                 TRACE_CATCH(ftape_start_tape(segment_id,head->sector_offset),);
 116         } else {
 117                 TRACE(ft_t_noise, "runner not idle, not starting tape");
 118         }
 119         /* go */
 120         result = fdc_setup_read_write(head, (mode == FT_WR_DELETE
 121                                              ? FDC_WRITE_DELETED : FDC_WRITE));
 122         ftape_set_state(wanted_state); /* should not be necessary */
 123         TRACE_EXIT result;
 124 }
 125
 126 /*  Wait until all data is actually written to tape.
 127  *
 128  *  There is a problem: when the tape runs into logical EOT, then this
 129  *  failes. We need to restart the runner in this case.
 130  */
 131 int ftape_loop_until_writes_done(void)
 132 {
 133         buffer_struct *head;
 134         TRACE_FUN(ft_t_flow);
 135
 136         while ((ft_driver_state == writing || ft_driver_state == deleting) &&
 137                ftape_get_buffer(ft_queue_head)->status != done) {
 138                 /* set the runner status to idle if at lEOT */
 139                 TRACE_CATCH(ftape_handle_logical_eot(), last_write_failed = 1);
 140                 /* restart the tape if necessary */
 141                 if (ft_runner_status == idle) {
 142                         TRACE(ft_t_noise, "runner is idle, restarting");
 143                         if (ft_driver_state == deleting) {
 144                                 TRACE_CATCH(ftape_start_writing(FT_WR_DELETE),
 145                                             last_write_failed = 1);
 146                         } else {
 147                                 TRACE_CATCH(ftape_start_writing(FT_WR_MULTI),
 148                                             last_write_failed = 1);
 149                         }
 150                 }
 151                 TRACE(ft_t_noise, "tail: %d, head: %d",
 152                       ftape_buffer_id(ft_queue_tail),
 153                       ftape_buffer_id(ft_queue_head));
 154                 TRACE_CATCH(fdc_interrupt_wait(5 * FT_SECOND),
 155                             last_write_failed = 1);
 156                 head = ftape_get_buffer(ft_queue_head);
 157                 if (head->status == error) {
 158                         /* Allow escape from loop when signaled !
 159                          */
 160                         FT_SIGNAL_EXIT(_DONT_BLOCK);
 161                         if (head->hard_error_map != 0) {
 162                                 /*  Implement hard write error recovery here
 163                                  */
 164                         }
 165                         /* retry this one */
 166                         head->status = waiting;
 167                         if (ft_runner_status == aborting) {
 168                                 ftape_dumb_stop();
 169                         }
 170                         if (ft_runner_status != idle) {
 171                                 TRACE_ABORT(-EIO, ft_t_err,
 172                                             "unexpected state: "
 173                                             "ft_runner_status != idle");
 174                         }
 175                         ftape_start_writing(ft_driver_state == deleting
 176                                             ? FT_WR_MULTI : FT_WR_DELETE);
 177                 }
 178                 TRACE(ft_t_noise, "looping until writes done");
 179         }
 180         ftape_set_state(idle);
 181         TRACE_EXIT 0;
 182 }
 183
 184 /*      Write given segment from buffer at address to tape.
 185  */
 186 static int write_segment(const int segment_id,
 187                          const void *address,
 188                          const ft_write_mode_t write_mode)
 189 {
 190         int bytes_written = 0;
 191         buffer_struct *tail;
 192         buffer_state_enum wanted_state = (write_mode == FT_WR_DELETE
 193                                           ? deleting : writing);
 194         TRACE_FUN(ft_t_flow);
 195
 196         TRACE(ft_t_noise, "segment_id = %d", segment_id);
 197         if (ft_driver_state != wanted_state) {
 198                 if (ft_driver_state == deleting ||
 199                     wanted_state == deleting) {
 200                         TRACE_CATCH(ftape_loop_until_writes_done(),);
 201                 }
 202                 TRACE(ft_t_noise, "calling ftape_abort_operation");
 203                 TRACE_CATCH(ftape_abort_operation(),);
 204                 ftape_zap_write_buffers();
 205                 ftape_set_state(wanted_state);
 206         }
 207         /*    if all buffers full we'll have to wait...
 208          */
 209         ftape_wait_segment(wanted_state);
 210         tail = ftape_get_buffer(ft_queue_tail);
 211         switch(tail->status) {
 212         case done:
 213                 ft_history.defects += count_ones(tail->hard_error_map);
 214                 break;
 215         case waiting:
 216                 /* this could happen with multiple EMPTY_SEGMENTs, but
 217                  * shouldn't happen any more as we re-start the runner even
 218                  * with an empty segment.
 219                  */
 220                 bytes_written = -EAGAIN;
 221                 break;
 222         case error:
 223                 /*  setup for a retry
 224                  */
 225                 tail->status = waiting;
 226                 bytes_written = -EAGAIN; /* force retry */
 227                 if (tail->hard_error_map != 0) {
 228                         TRACE(ft_t_warn,
 229                               "warning: %d hard error(s) in written segment",
 230                               count_ones(tail->hard_error_map));
 231                         TRACE(ft_t_noise, "hard_error_map = 0x%08lx",
 232                               (long)tail->hard_error_map);
 233                         /*  Implement hard write error recovery here
 234                          */
 235                 }
 236                 break;
 237         default:
 238                 TRACE_ABORT(-EIO, ft_t_err,
 239                             "wait for empty segment failed, tail status: %d",
 240                             tail->status);
 241         }
 242         /*    should runner stop ?
 243          */
 244         if (ft_runner_status == aborting) {
 245                 buffer_struct *head = ftape_get_buffer(ft_queue_head);
 246                 if (head->status == wanted_state) {
 247                         head->status = done; /* ???? */
 248                 }
 249                 /*  don't call abort_operation(), we don't want to zap
 250                  *  the dma buffers
 251                  */
 252                 TRACE_CATCH(ftape_dumb_stop(),);
 253         } else {
 254                 /*  If just passed last segment on tape: wait for BOT
 255                  *  or EOT mark. Sets ft_runner_status to idle if at lEOT
 256                  *  and successful
 257                  */
 258                 TRACE_CATCH(ftape_handle_logical_eot(),);
 259         }
 260         if (tail->status == done) {
 261                 /* now at least one buffer is empty, fill it with our
 262                  * data.  skip bad sectors and generate ecc.
 263                  * copy_and_gen_ecc return nr of bytes written, range
 264                  * 0..29 Kb inclusive!
 265                  *
 266                  * Empty segments are handled inside coyp_and_gen_ecc()
 267                  */
 268                 if (write_mode != FT_WR_DELETE) {
 269                         TRACE_CATCH(bytes_written = copy_and_gen_ecc(
 270                                 tail->address, address,
 271                                 ftape_get_bad_sector_entry(segment_id)),);
 272                 }
 273                 tail->segment_id = segment_id;
 274                 tail->status = waiting;
 275                 tail = ftape_next_buffer(ft_queue_tail);
 276         }
 277         /*  Start tape only if all buffers full or flush mode.
 278          *  This will give higher probability of streaming.
 279          */
 280         if (ft_runner_status != running &&
 281             ((tail->status == waiting &&
 282               ftape_get_buffer(ft_queue_head) == tail) ||
 283              write_mode != FT_WR_ASYNC)) {
 284                 TRACE_CATCH(ftape_start_writing(write_mode),);
 285         }
 286         TRACE_EXIT bytes_written;
 287 }
 288
 289 /*  Write as much as fits from buffer to the given segment on tape
 290  *  and handle retries.
 291  *  Return the number of bytes written (>= 0), or:
 292  *      -EIO          write failed
 293  *      -EINTR        interrupted by signal
 294  *      -ENOSPC       device full
 295  */
 296 int ftape_write_segment(const int segment_id,
 297                         const void *buffer,
 298                         const ft_write_mode_t flush)
 299 {
 300         int retry = 0;
 301         int result;
 302         TRACE_FUN(ft_t_flow);
 303
 304         ft_history.used |= 2;
 305         if (segment_id >= ft_tracks_per_tape*ft_segments_per_track) {
 306                 /* tape full */
 307                 TRACE_ABORT(-ENOSPC, ft_t_err,
 308                             "invalid segment id: %d (max %d)",
 309                             segment_id,
 310                             ft_tracks_per_tape * ft_segments_per_track -1);
 311         }
 312         for (;;) {
 313                 if ((result = write_segment(segment_id, buffer, flush)) >= 0) {
 314                         if (result == 0) { /* empty segment */
 315                                 TRACE(ft_t_noise,
 316                                       "empty segment, nothing written");
 317                         }
 318                         TRACE_EXIT result;
 319                 }
 320                 if (result == -EAGAIN) {
 321                         if (++retry > 100) { /* give up */
 322                                 TRACE_ABORT(-EIO, ft_t_err,
 323                                       "write failed, >100 retries in segment");
 324                         }
 325                         TRACE(ft_t_warn, "write error, retry %d (%d)",
 326                               retry,
 327                               ftape_get_buffer(ft_queue_tail)->segment_id);
 328                 } else {
 329                         TRACE_ABORT(result, ft_t_err,
 330                                     "write_segment failed, error: %d", result);
 331                 }
 332                 /* Allow escape from loop when signaled !
 333                  */
 334                 FT_SIGNAL_EXIT(_DONT_BLOCK);
 335         }
 336 }