drivers/s390/char/tape_std.c

   1 /*
   2  *  drivers/s390/char/tape_std.c
   3  *    standard tape device functions for ibm tapes.
   4  *
   5  *  S390 and zSeries version
   6  *    Copyright (C) 2001,2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
   7  *    Author(s): Carsten Otte <cotte@de.ibm.com>
   8  *               Michael Holzheu <holzheu@de.ibm.com>
   9  *               Tuan Ngo-Anh <ngoanh@de.ibm.com>
  10  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
  11  *               Stefan Bader <shbader@de.ibm.com>
  12  */
  13
  14 #include <linux/stddef.h>
  15 #include <linux/kernel.h>
  16 #include <linux/bio.h>
  17 #include <linux/timer.h>
  18
  19 #include <asm/types.h>
  20 #include <asm/idals.h>
  21 #include <asm/ebcdic.h>
  22 #include <asm/tape390.h>
  23
  24 #define TAPE_DBF_AREA   tape_core_dbf
  25
  26 #include "tape.h"
  27 #include "tape_std.h"
  28
  29 #define PRINTK_HEADER "TAPE_STD: "
  30
  31 /*
  32  * tape_std_assign
  33  */
  34 static void
  35 tape_std_assign_timeout(unsigned long data)
  36 {
  37         struct tape_request *   request;
  38         struct tape_device *    device;
  39         int rc;
  40
  41         request = (struct tape_request *) data;
  42         if ((device = request->device) == NULL)
  43                 BUG();
  44
  45         DBF_EVENT(3, "%08x: Assignment timeout. Device busy.\n",
  46                         device->cdev_id);
  47         rc = tape_cancel_io(device, request);
  48         if(rc)
  49                 PRINT_ERR("(%s): Assign timeout: Cancel failed with rc = %i\n",
  50                         device->cdev->dev.bus_id, rc);
  51
  52 }
  53
  54 int
  55 tape_std_assign(struct tape_device *device)
  56 {
  57         int                  rc;
  58         struct timer_list    timeout;
  59         struct tape_request *request;
  60
  61         request = tape_alloc_request(2, 11);
  62         if (IS_ERR(request))
  63                 return PTR_ERR(request);
  64
  65         request->op = TO_ASSIGN;
  66         tape_ccw_cc(request->cpaddr, ASSIGN, 11, request->cpdata);
  67         tape_ccw_end(request->cpaddr + 1, NOP, 0, NULL);
  68
  69         /*
  70          * The assign command sometimes blocks if the device is assigned
  71          * to another host (actually this shouldn't happen but it does).
  72          * So we set up a timeout for this call.
  73          */
  74         init_timer(&timeout);
  75         timeout.function = tape_std_assign_timeout;
  76         timeout.data     = (unsigned long) request;
  77         timeout.expires  = jiffies + 2 * HZ;
  78         add_timer(&timeout);
  79
  80         rc = tape_do_io_interruptible(device, request);
  81
  82         del_timer(&timeout);
  83
  84         if (rc != 0) {
  85                 PRINT_WARN("%s: assign failed - device might be busy\n",
  86                         device->cdev->dev.bus_id);
  87                 DBF_EVENT(3, "%08x: assign failed - device might be busy\n",
  88                         device->cdev_id);
  89         } else {
  90                 DBF_EVENT(3, "%08x: Tape assigned\n", device->cdev_id);
  91         }
  92         tape_free_request(request);
  93         return rc;
  94 }
  95
  96 /*
  97  * tape_std_unassign
  98  */
  99 int
 100 tape_std_unassign (struct tape_device *device)
 101 {
 102         int                  rc;
 103         struct tape_request *request;
 104
 105         if (device->tape_state == TS_NOT_OPER) {
 106                 DBF_EVENT(3, "(%08x): Can't unassign device\n",
 107                         device->cdev_id);
 108                 PRINT_WARN("(%s): Can't unassign device - device gone\n",
 109                         device->cdev->dev.bus_id);
 110                 return -EIO;
 111         }
 112
 113         request = tape_alloc_request(2, 11);
 114         if (IS_ERR(request))
 115                 return PTR_ERR(request);
 116
 117         request->op = TO_UNASSIGN;
 118         tape_ccw_cc(request->cpaddr, UNASSIGN, 11, request->cpdata);
 119         tape_ccw_end(request->cpaddr + 1, NOP, 0, NULL);
 120
 121         if ((rc = tape_do_io(device, request)) != 0) {
 122                 DBF_EVENT(3, "%08x: Unassign failed\n", device->cdev_id);
 123                 PRINT_WARN("%s: Unassign failed\n", device->cdev->dev.bus_id);
 124         } else {
 125                 DBF_EVENT(3, "%08x: Tape unassigned\n", device->cdev_id);
 126         }
 127         tape_free_request(request);
 128         return rc;
 129 }
 130
 131 /*
 132  * TAPE390_DISPLAY: Show a string on the tape display.
 133  */
 134 int
 135 tape_std_display(struct tape_device *device, struct display_struct *disp)
 136 {
 137         struct tape_request *request;
 138         int rc;
 139
 140         request = tape_alloc_request(2, 17);
 141         if (IS_ERR(request)) {
 142                 DBF_EVENT(3, "TAPE: load display failed\n");
 143                 return PTR_ERR(request);
 144         }
 145         request->op = TO_DIS;
 146
 147         *(unsigned char *) request->cpdata = disp->cntrl;
 148         DBF_EVENT(5, "TAPE: display cntrl=%04x\n", disp->cntrl);
 149         memcpy(((unsigned char *) request->cpdata) + 1, disp->message1, 8);
 150         memcpy(((unsigned char *) request->cpdata) + 9, disp->message2, 8);
 151         ASCEBC(((unsigned char*) request->cpdata) + 1, 16);
 152
 153         tape_ccw_cc(request->cpaddr, LOAD_DISPLAY, 17, request->cpdata);
 154         tape_ccw_end(request->cpaddr + 1, NOP, 0, NULL);
 155
 156         rc = tape_do_io_interruptible(device, request);
 157         tape_free_request(request);
 158         return rc;
 159 }
 160
 161 /*
 162  * Read block id.
 163  */
 164 int
 165 tape_std_read_block_id(struct tape_device *device, __u64 *id)
 166 {
 167         struct tape_request *request;
 168         int rc;
 169
 170         request = tape_alloc_request(3, 8);
 171         if (IS_ERR(request))
 172                 return PTR_ERR(request);
 173         request->op = TO_RBI;
 174         /* setup ccws */
 175         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 176         tape_ccw_cc(request->cpaddr + 1, READ_BLOCK_ID, 8, request->cpdata);
 177         tape_ccw_end(request->cpaddr + 2, NOP, 0, NULL);
 178         /* execute it */
 179         rc = tape_do_io(device, request);
 180         if (rc == 0)
 181                 /* Get result from read buffer. */
 182                 *id = *(__u64 *) request->cpdata;
 183         tape_free_request(request);
 184         return rc;
 185 }
 186
 187 int
 188 tape_std_terminate_write(struct tape_device *device)
 189 {
 190         int rc;
 191
 192         if(device->required_tapemarks == 0)
 193                 return 0;
 194
 195         DBF_LH(5, "tape%d: terminate write %dxEOF\n", device->first_minor,
 196                 device->required_tapemarks);
 197
 198         rc = tape_mtop(device, MTWEOF, device->required_tapemarks);
 199         if (rc)
 200                 return rc;
 201
 202         device->required_tapemarks = 0;
 203         return tape_mtop(device, MTBSR, 1);
 204 }
 205
 206 /*
 207  * MTLOAD: Loads the tape.
 208  * The default implementation just wait until the tape medium state changes
 209  * to MS_LOADED.
 210  */
 211 int
 212 tape_std_mtload(struct tape_device *device, int count)
 213 {
 214         return wait_event_interruptible(device->state_change_wq,
 215                 (device->medium_state == MS_LOADED));
 216 }
 217
 218 /*
 219  * MTSETBLK: Set block size.
 220  */
 221 int
 222 tape_std_mtsetblk(struct tape_device *device, int count)
 223 {
 224         struct idal_buffer *new;
 225
 226         DBF_LH(6, "tape_std_mtsetblk(%d)\n", count);
 227         if (count <= 0) {
 228                 /*
 229                  * Just set block_size to 0. tapechar_read/tapechar_write
 230                  * will realloc the idal buffer if a bigger one than the
 231                  * current is needed.
 232                  */
 233                 device->char_data.block_size = 0;
 234                 return 0;
 235         }
 236         if (device->char_data.idal_buf != NULL &&
 237             device->char_data.idal_buf->size == count)
 238                 /* We already have a idal buffer of that size. */
 239                 return 0;
 240
 241         if (count > MAX_BLOCKSIZE) {
 242                 DBF_EVENT(3, "Invalid block size (%d > %d) given.\n",
 243                         count, MAX_BLOCKSIZE);
 244                 PRINT_ERR("Invalid block size (%d > %d) given.\n",
 245                         count, MAX_BLOCKSIZE);
 246                 return -EINVAL;
 247         }
 248
 249         /* Allocate a new idal buffer. */
 250         new = idal_buffer_alloc(count, 0);
 251         if (new == NULL)
 252                 return -ENOMEM;
 253         if (device->char_data.idal_buf != NULL)
 254                 idal_buffer_free(device->char_data.idal_buf);
 255         device->char_data.idal_buf = new;
 256         device->char_data.block_size = count;
 257
 258         DBF_LH(6, "new blocksize is %d\n", device->char_data.block_size);
 259
 260         return 0;
 261 }
 262
 263 /*
 264  * MTRESET: Set block size to 0.
 265  */
 266 int
 267 tape_std_mtreset(struct tape_device *device, int count)
 268 {
 269         DBF_EVENT(6, "TCHAR:devreset:\n");
 270         device->char_data.block_size = 0;
 271         return 0;
 272 }
 273
 274 /*
 275  * MTFSF: Forward space over 'count' file marks. The tape is positioned
 276  * at the EOT (End of Tape) side of the file mark.
 277  */
 278 int
 279 tape_std_mtfsf(struct tape_device *device, int mt_count)
 280 {
 281         struct tape_request *request;
 282         struct ccw1 *ccw;
 283
 284         request = tape_alloc_request(mt_count + 2, 0);
 285         if (IS_ERR(request))
 286                 return PTR_ERR(request);
 287         request->op = TO_FSF;
 288         /* setup ccws */
 289         ccw = tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1,
 290                           device->modeset_byte);
 291         ccw = tape_ccw_repeat(ccw, FORSPACEFILE, mt_count);
 292         ccw = tape_ccw_end(ccw, NOP, 0, NULL);
 293
 294         /* execute it */
 295         return tape_do_io_free(device, request);
 296 }
 297
 298 /*
 299  * MTFSR: Forward space over 'count' tape blocks (blocksize is set
 300  * via MTSETBLK.
 301  */
 302 int
 303 tape_std_mtfsr(struct tape_device *device, int mt_count)
 304 {
 305         struct tape_request *request;
 306         struct ccw1 *ccw;
 307         int rc;
 308
 309         request = tape_alloc_request(mt_count + 2, 0);
 310         if (IS_ERR(request))
 311                 return PTR_ERR(request);
 312         request->op = TO_FSB;
 313         /* setup ccws */
 314         ccw = tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1,
 315                           device->modeset_byte);
 316         ccw = tape_ccw_repeat(ccw, FORSPACEBLOCK, mt_count);
 317         ccw = tape_ccw_end(ccw, NOP, 0, NULL);
 318
 319         /* execute it */
 320         rc = tape_do_io(device, request);
 321         if (rc == 0 && request->rescnt > 0) {
 322                 DBF_LH(3, "FSR over tapemark\n");
 323                 rc = 1;
 324         }
 325         tape_free_request(request);
 326
 327         return rc;
 328 }
 329
 330 /*
 331  * MTBSR: Backward space over 'count' tape blocks.
 332  * (blocksize is set via MTSETBLK.
 333  */
 334 int
 335 tape_std_mtbsr(struct tape_device *device, int mt_count)
 336 {
 337         struct tape_request *request;
 338         struct ccw1 *ccw;
 339         int rc;
 340
 341         request = tape_alloc_request(mt_count + 2, 0);
 342         if (IS_ERR(request))
 343                 return PTR_ERR(request);
 344         request->op = TO_BSB;
 345         /* setup ccws */
 346         ccw = tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1,
 347                           device->modeset_byte);
 348         ccw = tape_ccw_repeat(ccw, BACKSPACEBLOCK, mt_count);
 349         ccw = tape_ccw_end(ccw, NOP, 0, NULL);
 350
 351         /* execute it */
 352         rc = tape_do_io(device, request);
 353         if (rc == 0 && request->rescnt > 0) {
 354                 DBF_LH(3, "BSR over tapemark\n");
 355                 rc = 1;
 356         }
 357         tape_free_request(request);
 358
 359         return rc;
 360 }
 361
 362 /*
 363  * MTWEOF: Write 'count' file marks at the current position.
 364  */
 365 int
 366 tape_std_mtweof(struct tape_device *device, int mt_count)
 367 {
 368         struct tape_request *request;
 369         struct ccw1 *ccw;
 370
 371         request = tape_alloc_request(mt_count + 2, 0);
 372         if (IS_ERR(request))
 373                 return PTR_ERR(request);
 374         request->op = TO_WTM;
 375         /* setup ccws */
 376         ccw = tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1,
 377                           device->modeset_byte);
 378         ccw = tape_ccw_repeat(ccw, WRITETAPEMARK, mt_count);
 379         ccw = tape_ccw_end(ccw, NOP, 0, NULL);
 380
 381         /* execute it */
 382         return tape_do_io_free(device, request);
 383 }
 384
 385 /*
 386  * MTBSFM: Backward space over 'count' file marks.
 387  * The tape is positioned at the BOT (Begin Of Tape) side of the
 388  * last skipped file mark.
 389  */
 390 int
 391 tape_std_mtbsfm(struct tape_device *device, int mt_count)
 392 {
 393         struct tape_request *request;
 394         struct ccw1 *ccw;
 395
 396         request = tape_alloc_request(mt_count + 2, 0);
 397         if (IS_ERR(request))
 398                 return PTR_ERR(request);
 399         request->op = TO_BSF;
 400         /* setup ccws */
 401         ccw = tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1,
 402                           device->modeset_byte);
 403         ccw = tape_ccw_repeat(ccw, BACKSPACEFILE, mt_count);
 404         ccw = tape_ccw_end(ccw, NOP, 0, NULL);
 405
 406         /* execute it */
 407         return tape_do_io_free(device, request);
 408 }
 409
 410 /*
 411  * MTBSF: Backward space over 'count' file marks. The tape is positioned at
 412  * the EOT (End of Tape) side of the last skipped file mark.
 413  */
 414 int
 415 tape_std_mtbsf(struct tape_device *device, int mt_count)
 416 {
 417         struct tape_request *request;
 418         struct ccw1 *ccw;
 419         int rc;
 420
 421         request = tape_alloc_request(mt_count + 2, 0);
 422         if (IS_ERR(request))
 423                 return PTR_ERR(request);
 424         request->op = TO_BSF;
 425         /* setup ccws */
 426         ccw = tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1,
 427                           device->modeset_byte);
 428         ccw = tape_ccw_repeat(ccw, BACKSPACEFILE, mt_count);
 429         ccw = tape_ccw_end(ccw, NOP, 0, NULL);
 430         /* execute it */
 431         rc = tape_do_io_free(device, request);
 432         if (rc == 0) {
 433                 rc = tape_mtop(device, MTFSR, 1);
 434                 if (rc > 0)
 435                         rc = 0;
 436         }
 437         return rc;
 438 }
 439
 440 /*
 441  * MTFSFM: Forward space over 'count' file marks.
 442  * The tape is positioned at the BOT (Begin Of Tape) side
 443  * of the last skipped file mark.
 444  */
 445 int
 446 tape_std_mtfsfm(struct tape_device *device, int mt_count)
 447 {
 448         struct tape_request *request;
 449         struct ccw1 *ccw;
 450         int rc;
 451
 452         request = tape_alloc_request(mt_count + 2, 0);
 453         if (IS_ERR(request))
 454                 return PTR_ERR(request);
 455         request->op = TO_FSF;
 456         /* setup ccws */
 457         ccw = tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1,
 458                           device->modeset_byte);
 459         ccw = tape_ccw_repeat(ccw, FORSPACEFILE, mt_count);
 460         ccw = tape_ccw_end(ccw, NOP, 0, NULL);
 461         /* execute it */
 462         rc = tape_do_io_free(device, request);
 463         if (rc == 0) {
 464                 rc = tape_mtop(device, MTBSR, 1);
 465                 if (rc > 0)
 466                         rc = 0;
 467         }
 468
 469         return rc;
 470 }
 471
 472 /*
 473  * MTREW: Rewind the tape.
 474  */
 475 int
 476 tape_std_mtrew(struct tape_device *device, int mt_count)
 477 {
 478         struct tape_request *request;
 479
 480         request = tape_alloc_request(3, 0);
 481         if (IS_ERR(request))
 482                 return PTR_ERR(request);
 483         request->op = TO_REW;
 484         /* setup ccws */
 485         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1,
 486                     device->modeset_byte);
 487         tape_ccw_cc(request->cpaddr + 1, REWIND, 0, NULL);
 488         tape_ccw_end(request->cpaddr + 2, NOP, 0, NULL);
 489
 490         /* execute it */
 491         return tape_do_io_free(device, request);
 492 }
 493
 494 /*
 495  * MTOFFL: Rewind the tape and put the drive off-line.
 496  * Implement 'rewind unload'
 497  */
 498 int
 499 tape_std_mtoffl(struct tape_device *device, int mt_count)
 500 {
 501         struct tape_request *request;
 502
 503         request = tape_alloc_request(3, 0);
 504         if (IS_ERR(request))
 505                 return PTR_ERR(request);
 506         request->op = TO_RUN;
 507         /* setup ccws */
 508         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 509         tape_ccw_cc(request->cpaddr + 1, REWIND_UNLOAD, 0, NULL);
 510         tape_ccw_end(request->cpaddr + 2, NOP, 0, NULL);
 511
 512         /* execute it */
 513         return tape_do_io_free(device, request);
 514 }
 515
 516 /*
 517  * MTNOP: 'No operation'.
 518  */
 519 int
 520 tape_std_mtnop(struct tape_device *device, int mt_count)
 521 {
 522         struct tape_request *request;
 523
 524         request = tape_alloc_request(2, 0);
 525         if (IS_ERR(request))
 526                 return PTR_ERR(request);
 527         request->op = TO_NOP;
 528         /* setup ccws */
 529         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 530         tape_ccw_end(request->cpaddr + 1, NOP, 0, NULL);
 531         /* execute it */
 532         return tape_do_io_free(device, request);
 533 }
 534
 535 /*
 536  * MTEOM: positions at the end of the portion of the tape already used
 537  * for recordind data. MTEOM positions after the last file mark, ready for
 538  * appending another file.
 539  */
 540 int
 541 tape_std_mteom(struct tape_device *device, int mt_count)
 542 {
 543         int rc;
 544
 545         /*
 546          * Seek from the beginning of tape (rewind).
 547          */
 548         if ((rc = tape_mtop(device, MTREW, 1)) < 0)
 549                 return rc;
 550
 551         /*
 552          * The logical end of volume is given by two sewuential tapemarks.
 553          * Look for this by skipping to the next file (over one tapemark)
 554          * and then test for another one (fsr returns 1 if a tapemark was
 555          * encountered).
 556          */
 557         do {
 558                 if ((rc = tape_mtop(device, MTFSF, 1)) < 0)
 559                         return rc;
 560                 if ((rc = tape_mtop(device, MTFSR, 1)) < 0)
 561                         return rc;
 562         } while (rc == 0);
 563
 564         return tape_mtop(device, MTBSR, 1);
 565 }
 566
 567 /*
 568  * MTRETEN: Retension the tape, i.e. forward space to end of tape and rewind.
 569  */
 570 int
 571 tape_std_mtreten(struct tape_device *device, int mt_count)
 572 {
 573         struct tape_request *request;
 574         int rc;
 575
 576         request = tape_alloc_request(4, 0);
 577         if (IS_ERR(request))
 578                 return PTR_ERR(request);
 579         request->op = TO_FSF;
 580         /* setup ccws */
 581         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 582         tape_ccw_cc(request->cpaddr + 1,FORSPACEFILE, 0, NULL);
 583         tape_ccw_cc(request->cpaddr + 2, NOP, 0, NULL);
 584         tape_ccw_end(request->cpaddr + 3, CCW_CMD_TIC, 0, request->cpaddr);
 585         /* execute it, MTRETEN rc gets ignored */
 586         rc = tape_do_io_interruptible(device, request);
 587         tape_free_request(request);
 588         return tape_mtop(device, MTREW, 1);
 589 }
 590
 591 /*
 592  * MTERASE: erases the tape.
 593  */
 594 int
 595 tape_std_mterase(struct tape_device *device, int mt_count)
 596 {
 597         struct tape_request *request;
 598
 599         request = tape_alloc_request(6, 0);
 600         if (IS_ERR(request))
 601                 return PTR_ERR(request);
 602         request->op = TO_DSE;
 603         /* setup ccws */
 604         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 605         tape_ccw_cc(request->cpaddr + 1, REWIND, 0, NULL);
 606         tape_ccw_cc(request->cpaddr + 2, ERASE_GAP, 0, NULL);
 607         tape_ccw_cc(request->cpaddr + 3, DATA_SEC_ERASE, 0, NULL);
 608         tape_ccw_cc(request->cpaddr + 4, REWIND, 0, NULL);
 609         tape_ccw_end(request->cpaddr + 5, NOP, 0, NULL);
 610
 611         /* execute it */
 612         return tape_do_io_free(device, request);
 613 }
 614
 615 /*
 616  * MTUNLOAD: Rewind the tape and unload it.
 617  */
 618 int
 619 tape_std_mtunload(struct tape_device *device, int mt_count)
 620 {
 621         return tape_mtop(device, MTOFFL, mt_count);
 622 }
 623
 624 /*
 625  * MTCOMPRESSION: used to enable compression.
 626  * Sets the IDRC on/off.
 627  */
 628 int
 629 tape_std_mtcompression(struct tape_device *device, int mt_count)
 630 {
 631         struct tape_request *request;
 632
 633         if (mt_count < 0 || mt_count > 1) {
 634                 DBF_EXCEPTION(6, "xcom parm\n");
 635                 if (*device->modeset_byte & 0x08)
 636                         PRINT_INFO("(%s) Compression is currently on\n",
 637                                    device->cdev->dev.bus_id);
 638                 else
 639                         PRINT_INFO("(%s) Compression is currently off\n",
 640                                    device->cdev->dev.bus_id);
 641                 PRINT_INFO("Use 1 to switch compression on, 0 to "
 642                            "switch it off\n");
 643                 return -EINVAL;
 644         }
 645         request = tape_alloc_request(2, 0);
 646         if (IS_ERR(request))
 647                 return PTR_ERR(request);
 648         request->op = TO_NOP;
 649         /* setup ccws */
 650         if (mt_count == 0)
 651                 *device->modeset_byte &= ~0x08;
 652         else
 653                 *device->modeset_byte |= 0x08;
 654         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 655         tape_ccw_end(request->cpaddr + 1, NOP, 0, NULL);
 656         /* execute it */
 657         return tape_do_io_free(device, request);
 658 }
 659
 660 /*
 661  * Read Block
 662  */
 663 struct tape_request *
 664 tape_std_read_block(struct tape_device *device, size_t count)
 665 {
 666         struct tape_request *request;
 667
 668         /*
 669          * We have to alloc 4 ccws in order to be able to transform request
 670          * into a read backward request in error case.
 671          */
 672         request = tape_alloc_request(4, 0);
 673         if (IS_ERR(request)) {
 674                 DBF_EXCEPTION(6, "xrbl fail");
 675                 return request;
 676         }
 677         request->op = TO_RFO;
 678         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 679         tape_ccw_end_idal(request->cpaddr + 1, READ_FORWARD,
 680                           device->char_data.idal_buf);
 681         DBF_EVENT(6, "xrbl ccwg\n");
 682         return request;
 683 }
 684
 685 /*
 686  * Read Block backward transformation function.
 687  */
 688 void
 689 tape_std_read_backward(struct tape_device *device, struct tape_request *request)
 690 {
 691         /*
 692          * We have allocated 4 ccws in tape_std_read, so we can now
 693          * transform the request to a read backward, followed by a
 694          * forward space block.
 695          */
 696         request->op = TO_RBA;
 697         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 698         tape_ccw_cc_idal(request->cpaddr + 1, READ_BACKWARD,
 699                          device->char_data.idal_buf);
 700         tape_ccw_cc(request->cpaddr + 2, FORSPACEBLOCK, 0, NULL);
 701         tape_ccw_end(request->cpaddr + 3, NOP, 0, NULL);
 702         DBF_EVENT(6, "xrop ccwg");}
 703
 704 /*
 705  * Write Block
 706  */
 707 struct tape_request *
 708 tape_std_write_block(struct tape_device *device, size_t count)
 709 {
 710         struct tape_request *request;
 711
 712         request = tape_alloc_request(2, 0);
 713         if (IS_ERR(request)) {
 714                 DBF_EXCEPTION(6, "xwbl fail\n");
 715                 return request;
 716         }
 717         request->op = TO_WRI;
 718         tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 719         tape_ccw_end_idal(request->cpaddr + 1, WRITE_CMD,
 720                           device->char_data.idal_buf);
 721         DBF_EVENT(6, "xwbl ccwg\n");
 722         return request;
 723 }
 724
 725 /*
 726  * This routine is called by frontend after an ENOSP on write
 727  */
 728 void
 729 tape_std_process_eov(struct tape_device *device)
 730 {
 731         /*
 732          * End of volume: We have to backspace the last written record, then
 733          * we TRY to write a tapemark and then backspace over the written TM
 734          */
 735         if (tape_mtop(device, MTBSR, 1) == 0 &&
 736             tape_mtop(device, MTWEOF, 1) == 0) {
 737                 tape_mtop(device, MTBSR, 1);
 738         }
 739 }
 740
 741 EXPORT_SYMBOL(tape_std_assign);
 742 EXPORT_SYMBOL(tape_std_unassign);
 743 EXPORT_SYMBOL(tape_std_display);
 744 EXPORT_SYMBOL(tape_std_read_block_id);
 745 EXPORT_SYMBOL(tape_std_mtload);
 746 EXPORT_SYMBOL(tape_std_mtsetblk);
 747 EXPORT_SYMBOL(tape_std_mtreset);
 748 EXPORT_SYMBOL(tape_std_mtfsf);
 749 EXPORT_SYMBOL(tape_std_mtfsr);
 750 EXPORT_SYMBOL(tape_std_mtbsr);
 751 EXPORT_SYMBOL(tape_std_mtweof);
 752 EXPORT_SYMBOL(tape_std_mtbsfm);
 753 EXPORT_SYMBOL(tape_std_mtbsf);
 754 EXPORT_SYMBOL(tape_std_mtfsfm);
 755 EXPORT_SYMBOL(tape_std_mtrew);
 756 EXPORT_SYMBOL(tape_std_mtoffl);
 757 EXPORT_SYMBOL(tape_std_mtnop);
 758 EXPORT_SYMBOL(tape_std_mteom);
 759 EXPORT_SYMBOL(tape_std_mtreten);
 760 EXPORT_SYMBOL(tape_std_mterase);
 761 EXPORT_SYMBOL(tape_std_mtunload);
 762 EXPORT_SYMBOL(tape_std_mtcompression);
 763 EXPORT_SYMBOL(tape_std_read_block);
 764 EXPORT_SYMBOL(tape_std_read_backward);
 765 EXPORT_SYMBOL(tape_std_write_block);
 766 EXPORT_SYMBOL(tape_std_process_eov);