drivers/ide/ide-tape.c

   1 /*
   2  * IDE ATAPI streaming tape driver.
   3  *
   4  * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
   5  * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
   6  *
   7  * This driver was constructed as a student project in the software laboratory
   8  * of the faculty of electrical engineering in the Technion - Israel's
   9  * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
  10  *
  11  * It is hereby placed under the terms of the GNU general public license.
  12  * (See linux/COPYING).
  13  *
  14  * For a historical changelog see
  15  * Documentation/ide/ChangeLog.ide-tape.1995-2002
  16  */
  17
  18 #define DRV_NAME "ide-tape"
  19
  20 #define IDETAPE_VERSION "1.20"
  21
  22 #include <linux/module.h>
  23 #include <linux/types.h>
  24 #include <linux/string.h>
  25 #include <linux/kernel.h>
  26 #include <linux/delay.h>
  27 #include <linux/timer.h>
  28 #include <linux/mm.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/jiffies.h>
  31 #include <linux/major.h>
  32 #include <linux/errno.h>
  33 #include <linux/genhd.h>
  34 #include <linux/slab.h>
  35 #include <linux/pci.h>
  36 #include <linux/ide.h>
  37 #include <linux/smp_lock.h>
  38 #include <linux/completion.h>
  39 #include <linux/bitops.h>
  40 #include <linux/mutex.h>
  41 #include <scsi/scsi.h>
  42
  43 #include <asm/byteorder.h>
  44 #include <linux/irq.h>
  45 #include <linux/uaccess.h>
  46 #include <linux/io.h>
  47 #include <asm/unaligned.h>
  48 #include <linux/mtio.h>
  49
  50 enum {
  51         /* output errors only */
  52         DBG_ERR =               (1 << 0),
  53         /* output all sense key/asc */
  54         DBG_SENSE =             (1 << 1),
  55         /* info regarding all chrdev-related procedures */
  56         DBG_CHRDEV =            (1 << 2),
  57         /* all remaining procedures */
  58         DBG_PROCS =             (1 << 3),
  59 };
  60
  61 /* define to see debug info */
  62 #define IDETAPE_DEBUG_LOG               0
  63
  64 #if IDETAPE_DEBUG_LOG
  65 #define debug_log(lvl, fmt, args...)                    \
  66 {                                                       \
  67         if (tape->debug_mask & lvl)                     \
  68         printk(KERN_INFO "ide-tape: " fmt, ## args);    \
  69 }
  70 #else
  71 #define debug_log(lvl, fmt, args...) do {} while (0)
  72 #endif
  73
  74 /**************************** Tunable parameters *****************************/
  75 /*
  76  * After each failed packet command we issue a request sense command and retry
  77  * the packet command IDETAPE_MAX_PC_RETRIES times.
  78  *
  79  * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
  80  */
  81 #define IDETAPE_MAX_PC_RETRIES          3
  82
  83 /*
  84  * Some drives (for example, Seagate STT3401A Travan) require a very long
  85  * timeout, because they don't return an interrupt or clear their busy bit
  86  * until after the command completes (even retension commands).
  87  */
  88 #define IDETAPE_WAIT_CMD                (900*HZ)
  89
  90 /*
  91  * The following parameter is used to select the point in the internal tape fifo
  92  * in which we will start to refill the buffer. Decreasing the following
  93  * parameter will improve the system's latency and interactive response, while
  94  * using a high value might improve system throughput.
  95  */
  96 #define IDETAPE_FIFO_THRESHOLD          2
  97
  98 /*
  99  * DSC polling parameters.
 100  *
 101  * Polling for DSC (a single bit in the status register) is a very important
 102  * function in ide-tape. There are two cases in which we poll for DSC:
 103  *
 104  * 1. Before a read/write packet command, to ensure that we can transfer data
 105  * from/to the tape's data buffers, without causing an actual media access.
 106  * In case the tape is not ready yet, we take out our request from the device
 107  * request queue, so that ide.c could service requests from the other device
 108  * on the same interface in the meantime.
 109  *
 110  * 2. After the successful initialization of a "media access packet command",
 111  * which is a command that can take a long time to complete (the interval can
 112  * range from several seconds to even an hour). Again, we postpone our request
 113  * in the middle to free the bus for the other device. The polling frequency
 114  * here should be lower than the read/write frequency since those media access
 115  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
 116  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
 117  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
 118  *
 119  * We also set a timeout for the timer, in case something goes wrong. The
 120  * timeout should be longer then the maximum execution time of a tape operation.
 121  */
 122
 123 /* DSC timings. */
 124 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
 125 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
 126 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
 127 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
 128 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
 129 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
 130 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
 131
 132 /*************************** End of tunable parameters ***********************/
 133
 134 /* tape directions */
 135 enum {
 136         IDETAPE_DIR_NONE  = (1 << 0),
 137         IDETAPE_DIR_READ  = (1 << 1),
 138         IDETAPE_DIR_WRITE = (1 << 2),
 139 };
 140
 141 struct idetape_bh {
 142         u32 b_size;
 143         atomic_t b_count;
 144         struct idetape_bh *b_reqnext;
 145         char *b_data;
 146 };
 147
 148 /* Tape door status */
 149 #define DOOR_UNLOCKED                   0
 150 #define DOOR_LOCKED                     1
 151 #define DOOR_EXPLICITLY_LOCKED          2
 152
 153 /* Some defines for the SPACE command */
 154 #define IDETAPE_SPACE_OVER_FILEMARK     1
 155 #define IDETAPE_SPACE_TO_EOD            3
 156
 157 /* Some defines for the LOAD UNLOAD command */
 158 #define IDETAPE_LU_LOAD_MASK            1
 159 #define IDETAPE_LU_RETENSION_MASK       2
 160 #define IDETAPE_LU_EOT_MASK             4
 161
 162 /* Error codes returned in rq->errors to the higher part of the driver. */
 163 #define IDETAPE_ERROR_GENERAL           101
 164 #define IDETAPE_ERROR_FILEMARK          102
 165 #define IDETAPE_ERROR_EOD               103
 166
 167 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
 168 #define IDETAPE_BLOCK_DESCRIPTOR        0
 169 #define IDETAPE_CAPABILITIES_PAGE       0x2a
 170
 171 /*
 172  * Most of our global data which we need to save even as we leave the driver due
 173  * to an interrupt or a timer event is stored in the struct defined below.
 174  */
 175 typedef struct ide_tape_obj {
 176         ide_drive_t     *drive;
 177         ide_driver_t    *driver;
 178         struct gendisk  *disk;
 179         struct kref     kref;
 180
 181         /*
 182          *      pc points to the current processed packet command.
 183          *
 184          *      failed_pc points to the last failed packet command, or contains
 185          *      NULL if we do not need to retry any packet command. This is
 186          *      required since an additional packet command is needed before the
 187          *      retry, to get detailed information on what went wrong.
 188          */
 189         /* Current packet command */
 190         struct ide_atapi_pc *pc;
 191         /* Last failed packet command */
 192         struct ide_atapi_pc *failed_pc;
 193         /* used by REQ_IDETAPE_{READ,WRITE} requests */
 194         struct ide_atapi_pc queued_pc;
 195
 196         struct ide_atapi_pc request_sense_pc;
 197         struct request request_sense_rq;
 198
 199         /*
 200          * DSC polling variables.
 201          *
 202          * While polling for DSC we use postponed_rq to postpone the current
 203          * request so that ide.c will be able to service pending requests on the
 204          * other device. Note that at most we will have only one DSC (usually
 205          * data transfer) request in the device request queue.
 206          */
 207         struct request *postponed_rq;
 208         /* The time in which we started polling for DSC */
 209         unsigned long dsc_polling_start;
 210         /* Timer used to poll for dsc */
 211         struct timer_list dsc_timer;
 212         /* Read/Write dsc polling frequency */
 213         unsigned long best_dsc_rw_freq;
 214         unsigned long dsc_poll_freq;
 215         unsigned long dsc_timeout;
 216
 217         /* Read position information */
 218         u8 partition;
 219         /* Current block */
 220         unsigned int first_frame;
 221
 222         /* Last error information */
 223         u8 sense_key, asc, ascq;
 224
 225         /* Character device operation */
 226         unsigned int minor;
 227         /* device name */
 228         char name[4];
 229         /* Current character device data transfer direction */
 230         u8 chrdev_dir;
 231
 232         /* tape block size, usually 512 or 1024 bytes */
 233         unsigned short blk_size;
 234         int user_bs_factor;
 235
 236         /* Copy of the tape's Capabilities and Mechanical Page */
 237         u8 caps[20];
 238
 239         /*
 240          * Active data transfer request parameters.
 241          *
 242          * At most, there is only one ide-tape originated data transfer request
 243          * in the device request queue. This allows ide.c to easily service
 244          * requests from the other device when we postpone our active request.
 245          */
 246
 247         /* Data buffer size chosen based on the tape's recommendation */
 248         int buffer_size;
 249         /* merge buffer */
 250         struct idetape_bh *merge_bh;
 251         /* size of the merge buffer */
 252         int merge_bh_size;
 253         /* pointer to current buffer head within the merge buffer */
 254         struct idetape_bh *bh;
 255         char *b_data;
 256         int b_count;
 257
 258         int pages_per_buffer;
 259         /* Wasted space in each stage */
 260         int excess_bh_size;
 261
 262         /* protects the ide-tape queue */
 263         spinlock_t lock;
 264
 265         /* Measures average tape speed */
 266         unsigned long avg_time;
 267         int avg_size;
 268         int avg_speed;
 269
 270         /* the door is currently locked */
 271         int door_locked;
 272         /* the tape hardware is write protected */
 273         char drv_write_prot;
 274         /* the tape is write protected (hardware or opened as read-only) */
 275         char write_prot;
 276
 277         u32 debug_mask;
 278 } idetape_tape_t;
 279
 280 static DEFINE_MUTEX(idetape_ref_mutex);
 281
 282 static struct class *idetape_sysfs_class;
 283
 284 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
 285
 286 #define ide_tape_g(disk) \
 287         container_of((disk)->private_data, struct ide_tape_obj, driver)
 288
 289 static void ide_tape_release(struct kref *);
 290
 291 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
 292 {
 293         struct ide_tape_obj *tape = NULL;
 294
 295         mutex_lock(&idetape_ref_mutex);
 296         tape = ide_tape_g(disk);
 297         if (tape) {
 298                 if (ide_device_get(tape->drive))
 299                         tape = NULL;
 300                 else
 301                         kref_get(&tape->kref);
 302         }
 303         mutex_unlock(&idetape_ref_mutex);
 304         return tape;
 305 }
 306
 307 static void ide_tape_put(struct ide_tape_obj *tape)
 308 {
 309         ide_drive_t *drive = tape->drive;
 310
 311         mutex_lock(&idetape_ref_mutex);
 312         kref_put(&tape->kref, ide_tape_release);
 313         ide_device_put(drive);
 314         mutex_unlock(&idetape_ref_mutex);
 315 }
 316
 317 /*
 318  * The variables below are used for the character device interface. Additional
 319  * state variables are defined in our ide_drive_t structure.
 320  */
 321 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
 322
 323 #define ide_tape_f(file) ((file)->private_data)
 324
 325 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
 326 {
 327         struct ide_tape_obj *tape = NULL;
 328
 329         mutex_lock(&idetape_ref_mutex);
 330         tape = idetape_devs[i];
 331         if (tape)
 332                 kref_get(&tape->kref);
 333         mutex_unlock(&idetape_ref_mutex);
 334         return tape;
 335 }
 336
 337 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
 338                                   unsigned int bcount)
 339 {
 340         struct idetape_bh *bh = pc->bh;
 341         int count;
 342
 343         while (bcount) {
 344                 if (bh == NULL) {
 345                         printk(KERN_ERR "ide-tape: bh == NULL in "
 346                                 "idetape_input_buffers\n");
 347                         ide_pad_transfer(drive, 0, bcount);
 348                         return;
 349                 }
 350                 count = min(
 351                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
 352                         bcount);
 353                 drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
 354                                         atomic_read(&bh->b_count), count);
 355                 bcount -= count;
 356                 atomic_add(count, &bh->b_count);
 357                 if (atomic_read(&bh->b_count) == bh->b_size) {
 358                         bh = bh->b_reqnext;
 359                         if (bh)
 360                                 atomic_set(&bh->b_count, 0);
 361                 }
 362         }
 363         pc->bh = bh;
 364 }
 365
 366 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
 367                                    unsigned int bcount)
 368 {
 369         struct idetape_bh *bh = pc->bh;
 370         int count;
 371
 372         while (bcount) {
 373                 if (bh == NULL) {
 374                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
 375                                         __func__);
 376                         return;
 377                 }
 378                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
 379                 drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
 380                 bcount -= count;
 381                 pc->b_data += count;
 382                 pc->b_count -= count;
 383                 if (!pc->b_count) {
 384                         bh = bh->b_reqnext;
 385                         pc->bh = bh;
 386                         if (bh) {
 387                                 pc->b_data = bh->b_data;
 388                                 pc->b_count = atomic_read(&bh->b_count);
 389                         }
 390                 }
 391         }
 392 }
 393
 394 static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
 395 {
 396         struct idetape_bh *bh = pc->bh;
 397         int count;
 398         unsigned int bcount = pc->xferred;
 399
 400         if (pc->flags & PC_FLAG_WRITING)
 401                 return;
 402         while (bcount) {
 403                 if (bh == NULL) {
 404                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
 405                                         __func__);
 406                         return;
 407                 }
 408                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
 409                 atomic_set(&bh->b_count, count);
 410                 if (atomic_read(&bh->b_count) == bh->b_size)
 411                         bh = bh->b_reqnext;
 412                 bcount -= count;
 413         }
 414         pc->bh = bh;
 415 }
 416
 417 /*
 418  * called on each failed packet command retry to analyze the request sense. We
 419  * currently do not utilize this information.
 420  */
 421 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 422 {
 423         idetape_tape_t *tape = drive->driver_data;
 424         struct ide_atapi_pc *pc = tape->failed_pc;
 425
 426         tape->sense_key = sense[2] & 0xF;
 427         tape->asc       = sense[12];
 428         tape->ascq      = sense[13];
 429
 430         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
 431                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
 432
 433         /* Correct pc->xferred by asking the tape.       */
 434         if (pc->flags & PC_FLAG_DMA_ERROR) {
 435                 pc->xferred = pc->req_xfer -
 436                         tape->blk_size *
 437                         get_unaligned_be32(&sense[3]);
 438                 idetape_update_buffers(drive, pc);
 439         }
 440
 441         /*
 442          * If error was the result of a zero-length read or write command,
 443          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
 444          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
 445          */
 446         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
 447             /* length == 0 */
 448             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
 449                 if (tape->sense_key == 5) {
 450                         /* don't report an error, everything's ok */
 451                         pc->error = 0;
 452                         /* don't retry read/write */
 453                         pc->flags |= PC_FLAG_ABORT;
 454                 }
 455         }
 456         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
 457                 pc->error = IDETAPE_ERROR_FILEMARK;
 458                 pc->flags |= PC_FLAG_ABORT;
 459         }
 460         if (pc->c[0] == WRITE_6) {
 461                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
 462                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
 463                         pc->error = IDETAPE_ERROR_EOD;
 464                         pc->flags |= PC_FLAG_ABORT;
 465                 }
 466         }
 467         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
 468                 if (tape->sense_key == 8) {
 469                         pc->error = IDETAPE_ERROR_EOD;
 470                         pc->flags |= PC_FLAG_ABORT;
 471                 }
 472                 if (!(pc->flags & PC_FLAG_ABORT) &&
 473                     pc->xferred)
 474                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
 475         }
 476 }
 477
 478 /* Free data buffers completely. */
 479 static void ide_tape_kfree_buffer(idetape_tape_t *tape)
 480 {
 481         struct idetape_bh *prev_bh, *bh = tape->merge_bh;
 482
 483         while (bh) {
 484                 u32 size = bh->b_size;
 485
 486                 while (size) {
 487                         unsigned int order = fls(size >> PAGE_SHIFT)-1;
 488
 489                         if (bh->b_data)
 490                                 free_pages((unsigned long)bh->b_data, order);
 491
 492                         size &= (order-1);
 493                         bh->b_data += (1 << order) * PAGE_SIZE;
 494                 }
 495                 prev_bh = bh;
 496                 bh = bh->b_reqnext;
 497                 kfree(prev_bh);
 498         }
 499 }
 500
 501 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
 502 {
 503         struct request *rq = HWGROUP(drive)->rq;
 504         idetape_tape_t *tape = drive->driver_data;
 505         unsigned long flags;
 506         int error;
 507
 508         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 509
 510         switch (uptodate) {
 511         case 0: error = IDETAPE_ERROR_GENERAL; break;
 512         case 1: error = 0; break;
 513         default: error = uptodate;
 514         }
 515         rq->errors = error;
 516         if (error)
 517                 tape->failed_pc = NULL;
 518
 519         if (!blk_special_request(rq)) {
 520                 ide_end_request(drive, uptodate, nr_sects);
 521                 return 0;
 522         }
 523
 524         spin_lock_irqsave(&tape->lock, flags);
 525
 526         ide_end_drive_cmd(drive, 0, 0);
 527
 528         spin_unlock_irqrestore(&tape->lock, flags);
 529         return 0;
 530 }
 531
 532 static void ide_tape_callback(ide_drive_t *drive)
 533 {
 534         idetape_tape_t *tape = drive->driver_data;
 535         struct ide_atapi_pc *pc = tape->pc;
 536         int uptodate = pc->error ? 0 : 1;
 537
 538         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 539
 540         if (tape->failed_pc == pc)
 541                 tape->failed_pc = NULL;
 542
 543         if (pc->c[0] == REQUEST_SENSE) {
 544                 if (uptodate)
 545                         idetape_analyze_error(drive, pc->buf);
 546                 else
 547                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
 548                                         "itself - Aborting request!\n");
 549         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
 550                 struct request *rq = drive->hwif->hwgroup->rq;
 551                 int blocks = pc->xferred / tape->blk_size;
 552
 553                 tape->avg_size += blocks * tape->blk_size;
 554
 555                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
 556                         tape->avg_speed = tape->avg_size * HZ /
 557                                 (jiffies - tape->avg_time) / 1024;
 558                         tape->avg_size = 0;
 559                         tape->avg_time = jiffies;
 560                 }
 561
 562                 tape->first_frame += blocks;
 563                 rq->current_nr_sectors -= blocks;
 564
 565                 if (pc->error)
 566                         uptodate = pc->error;
 567         } else if (pc->c[0] == READ_POSITION && uptodate) {
 568                 u8 *readpos = tape->pc->buf;
 569
 570                 debug_log(DBG_SENSE, "BOP - %s\n",
 571                                 (readpos[0] & 0x80) ? "Yes" : "No");
 572                 debug_log(DBG_SENSE, "EOP - %s\n",
 573                                 (readpos[0] & 0x40) ? "Yes" : "No");
 574
 575                 if (readpos[0] & 0x4) {
 576                         printk(KERN_INFO "ide-tape: Block location is unknown"
 577                                          "to the tape\n");
 578                         clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
 579                         uptodate = 0;
 580                 } else {
 581                         debug_log(DBG_SENSE, "Block Location - %u\n",
 582                                         be32_to_cpup((__be32 *)&readpos[4]));
 583
 584                         tape->partition = readpos[1];
 585                         tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
 586                         set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
 587                 }
 588         }
 589
 590         idetape_end_request(drive, uptodate, 0);
 591 }
 592
 593 static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
 594 {
 595         ide_init_pc(pc);
 596         pc->c[0] = REQUEST_SENSE;
 597         pc->c[4] = 20;
 598         pc->req_xfer = 20;
 599 }
 600
 601 /*
 602  *      idetape_retry_pc is called when an error was detected during the
 603  *      last packet command. We queue a request sense packet command in
 604  *      the head of the request list.
 605  */
 606 static void idetape_retry_pc(ide_drive_t *drive)
 607 {
 608         struct ide_tape_obj *tape = drive->driver_data;
 609         struct request *rq = &tape->request_sense_rq;
 610         struct ide_atapi_pc *pc = &tape->request_sense_pc;
 611
 612         (void)ide_read_error(drive);
 613         idetape_create_request_sense_cmd(pc);
 614         set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
 615         ide_queue_pc_head(drive, tape->disk, pc, rq);
 616 }
 617
 618 /*
 619  * Postpone the current request so that ide.c will be able to service requests
 620  * from another device on the same hwgroup while we are polling for DSC.
 621  */
 622 static void idetape_postpone_request(ide_drive_t *drive)
 623 {
 624         idetape_tape_t *tape = drive->driver_data;
 625
 626         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 627
 628         tape->postponed_rq = HWGROUP(drive)->rq;
 629         ide_stall_queue(drive, tape->dsc_poll_freq);
 630 }
 631
 632 static void ide_tape_handle_dsc(ide_drive_t *drive)
 633 {
 634         idetape_tape_t *tape = drive->driver_data;
 635
 636         /* Media access command */
 637         tape->dsc_polling_start = jiffies;
 638         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
 639         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
 640         /* Allow ide.c to handle other requests */
 641         idetape_postpone_request(drive);
 642 }
 643
 644 static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
 645                                 unsigned int bcount, int write)
 646 {
 647         if (write)
 648                 idetape_output_buffers(drive, pc, bcount);
 649         else
 650                 idetape_input_buffers(drive, pc, bcount);
 651
 652         return bcount;
 653 }
 654
 655 /*
 656  * This is the usual interrupt handler which will be called during a packet
 657  * command. We will transfer some of the data (as requested by the drive) and
 658  * will re-point interrupt handler to us. When data transfer is finished, we
 659  * will act according to the algorithm described before
 660  * idetape_issue_pc.
 661  */
 662 static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
 663 {
 664         idetape_tape_t *tape = drive->driver_data;
 665
 666         return ide_pc_intr(drive, tape->pc, idetape_pc_intr, IDETAPE_WAIT_CMD,
 667                            NULL, idetape_update_buffers, idetape_retry_pc,
 668                            ide_tape_handle_dsc, ide_tape_io_buffers);
 669 }
 670
 671 /*
 672  * Packet Command Interface
 673  *
 674  * The current Packet Command is available in tape->pc, and will not change
 675  * until we finish handling it. Each packet command is associated with a
 676  * callback function that will be called when the command is finished.
 677  *
 678  * The handling will be done in three stages:
 679  *
 680  * 1. idetape_issue_pc will send the packet command to the drive, and will set
 681  * the interrupt handler to idetape_pc_intr.
 682  *
 683  * 2. On each interrupt, idetape_pc_intr will be called. This step will be
 684  * repeated until the device signals us that no more interrupts will be issued.
 685  *
 686  * 3. ATAPI Tape media access commands have immediate status with a delayed
 687  * process. In case of a successful initiation of a media access packet command,
 688  * the DSC bit will be set when the actual execution of the command is finished.
 689  * Since the tape drive will not issue an interrupt, we have to poll for this
 690  * event. In this case, we define the request as "low priority request" by
 691  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
 692  * exit the driver.
 693  *
 694  * ide.c will then give higher priority to requests which originate from the
 695  * other device, until will change rq_status to RQ_ACTIVE.
 696  *
 697  * 4. When the packet command is finished, it will be checked for errors.
 698  *
 699  * 5. In case an error was found, we queue a request sense packet command in
 700  * front of the request queue and retry the operation up to
 701  * IDETAPE_MAX_PC_RETRIES times.
 702  *
 703  * 6. In case no error was found, or we decided to give up and not to retry
 704  * again, the callback function will be called and then we will handle the next
 705  * request.
 706  */
 707 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
 708 {
 709         idetape_tape_t *tape = drive->driver_data;
 710
 711         return ide_transfer_pc(drive, tape->pc, idetape_pc_intr,
 712                                IDETAPE_WAIT_CMD, NULL);
 713 }
 714
 715 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
 716                 struct ide_atapi_pc *pc)
 717 {
 718         idetape_tape_t *tape = drive->driver_data;
 719
 720         if (tape->pc->c[0] == REQUEST_SENSE &&
 721             pc->c[0] == REQUEST_SENSE) {
 722                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
 723                         "Two request sense in serial were issued\n");
 724         }
 725
 726         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
 727                 tape->failed_pc = pc;
 728         /* Set the current packet command */
 729         tape->pc = pc;
 730
 731         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
 732                 (pc->flags & PC_FLAG_ABORT)) {
 733                 /*
 734                  * We will "abort" retrying a packet command in case legitimate
 735                  * error code was received (crossing a filemark, or end of the
 736                  * media, for example).
 737                  */
 738                 if (!(pc->flags & PC_FLAG_ABORT)) {
 739                         if (!(pc->c[0] == TEST_UNIT_READY &&
 740                               tape->sense_key == 2 && tape->asc == 4 &&
 741                              (tape->ascq == 1 || tape->ascq == 8))) {
 742                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
 743                                                 "pc = %2x, key = %2x, "
 744                                                 "asc = %2x, ascq = %2x\n",
 745                                                 tape->name, pc->c[0],
 746                                                 tape->sense_key, tape->asc,
 747                                                 tape->ascq);
 748                         }
 749                         /* Giving up */
 750                         pc->error = IDETAPE_ERROR_GENERAL;
 751                 }
 752                 tape->failed_pc = NULL;
 753                 drive->pc_callback(drive);
 754                 return ide_stopped;
 755         }
 756         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
 757
 758         pc->retries++;
 759
 760         return ide_issue_pc(drive, pc, idetape_transfer_pc,
 761                             IDETAPE_WAIT_CMD, NULL);
 762 }
 763
 764 /* A mode sense command is used to "sense" tape parameters. */
 765 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
 766 {
 767         ide_init_pc(pc);
 768         pc->c[0] = MODE_SENSE;
 769         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
 770                 /* DBD = 1 - Don't return block descriptors */
 771                 pc->c[1] = 8;
 772         pc->c[2] = page_code;
 773         /*
 774          * Changed pc->c[3] to 0 (255 will at best return unused info).
 775          *
 776          * For SCSI this byte is defined as subpage instead of high byte
 777          * of length and some IDE drives seem to interpret it this way
 778          * and return an error when 255 is used.
 779          */
 780         pc->c[3] = 0;
 781         /* We will just discard data in that case */
 782         pc->c[4] = 255;
 783         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
 784                 pc->req_xfer = 12;
 785         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
 786                 pc->req_xfer = 24;
 787         else
 788                 pc->req_xfer = 50;
 789 }
 790
 791 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
 792 {
 793         ide_hwif_t *hwif = drive->hwif;
 794         idetape_tape_t *tape = drive->driver_data;
 795         struct ide_atapi_pc *pc = tape->pc;
 796         u8 stat;
 797
 798         stat = hwif->tp_ops->read_status(hwif);
 799
 800         if (stat & ATA_DSC) {
 801                 if (stat & ATA_ERR) {
 802                         /* Error detected */
 803                         if (pc->c[0] != TEST_UNIT_READY)
 804                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
 805                                                 tape->name);
 806                         /* Retry operation */
 807                         idetape_retry_pc(drive);
 808                         return ide_stopped;
 809                 }
 810                 pc->error = 0;
 811         } else {
 812                 pc->error = IDETAPE_ERROR_GENERAL;
 813                 tape->failed_pc = NULL;
 814         }
 815         drive->pc_callback(drive);
 816         return ide_stopped;
 817 }
 818
 819 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
 820                                    struct ide_atapi_pc *pc, struct request *rq,
 821                                    u8 opcode)
 822 {
 823         struct idetape_bh *bh = (struct idetape_bh *)rq->special;
 824         unsigned int length = rq->current_nr_sectors;
 825
 826         ide_init_pc(pc);
 827         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
 828         pc->c[1] = 1;
 829         pc->bh = bh;
 830         pc->buf = NULL;
 831         pc->buf_size = length * tape->blk_size;
 832         pc->req_xfer = pc->buf_size;
 833         if (pc->req_xfer == tape->buffer_size)
 834                 pc->flags |= PC_FLAG_DMA_OK;
 835
 836         if (opcode == READ_6) {
 837                 pc->c[0] = READ_6;
 838                 atomic_set(&bh->b_count, 0);
 839         } else if (opcode == WRITE_6) {
 840                 pc->c[0] = WRITE_6;
 841                 pc->flags |= PC_FLAG_WRITING;
 842                 pc->b_data = bh->b_data;
 843                 pc->b_count = atomic_read(&bh->b_count);
 844         }
 845
 846         memcpy(rq->cmd, pc->c, 12);
 847 }
 848
 849 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 850                                           struct request *rq, sector_t block)
 851 {
 852         ide_hwif_t *hwif = drive->hwif;
 853         idetape_tape_t *tape = drive->driver_data;
 854         struct ide_atapi_pc *pc = NULL;
 855         struct request *postponed_rq = tape->postponed_rq;
 856         u8 stat;
 857
 858         debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
 859                         " current_nr_sectors: %u\n",
 860                         (unsigned long long)rq->sector, rq->nr_sectors,
 861                         rq->current_nr_sectors);
 862
 863         if (!blk_special_request(rq)) {
 864                 /* We do not support buffer cache originated requests. */
 865                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
 866                         "request queue (%d)\n", drive->name, rq->cmd_type);
 867                 ide_end_request(drive, 0, 0);
 868                 return ide_stopped;
 869         }
 870
 871         /* Retry a failed packet command */
 872         if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE) {
 873                 pc = tape->failed_pc;
 874                 goto out;
 875         }
 876
 877         if (postponed_rq != NULL)
 878                 if (rq != postponed_rq) {
 879                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
 880                                         "Two DSC requests were queued\n");
 881                         idetape_end_request(drive, 0, 0);
 882                         return ide_stopped;
 883                 }
 884
 885         tape->postponed_rq = NULL;
 886
 887         /*
 888          * If the tape is still busy, postpone our request and service
 889          * the other device meanwhile.
 890          */
 891         stat = hwif->tp_ops->read_status(hwif);
 892
 893         if (!drive->dsc_overlap && !(rq->cmd[13] & REQ_IDETAPE_PC2))
 894                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
 895
 896         if (drive->post_reset == 1) {
 897                 set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
 898                 drive->post_reset = 0;
 899         }
 900
 901         if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
 902             (stat & ATA_DSC) == 0) {
 903                 if (postponed_rq == NULL) {
 904                         tape->dsc_polling_start = jiffies;
 905                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
 906                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
 907                 } else if (time_after(jiffies, tape->dsc_timeout)) {
 908                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
 909                                 tape->name);
 910                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
 911                                 idetape_media_access_finished(drive);
 912                                 return ide_stopped;
 913                         } else {
 914                                 return ide_do_reset(drive);
 915                         }
 916                 } else if (time_after(jiffies,
 917                                         tape->dsc_polling_start +
 918                                         IDETAPE_DSC_MA_THRESHOLD))
 919                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
 920                 idetape_postpone_request(drive);
 921                 return ide_stopped;
 922         }
 923         if (rq->cmd[13] & REQ_IDETAPE_READ) {
 924                 pc = &tape->queued_pc;
 925                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
 926                 goto out;
 927         }
 928         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
 929                 pc = &tape->queued_pc;
 930                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
 931                 goto out;
 932         }
 933         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
 934                 pc = (struct ide_atapi_pc *) rq->buffer;
 935                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
 936                 rq->cmd[13] |= REQ_IDETAPE_PC2;
 937                 goto out;
 938         }
 939         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
 940                 idetape_media_access_finished(drive);
 941                 return ide_stopped;
 942         }
 943         BUG();
 944
 945 out:
 946         return idetape_issue_pc(drive, pc);
 947 }
 948
 949 /*
 950  * The function below uses __get_free_pages to allocate a data buffer of size
 951  * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
 952  * much as possible.
 953  *
 954  * It returns a pointer to the newly allocated buffer, or NULL in case of
 955  * failure.
 956  */
 957 static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
 958                                                   int full, int clear)
 959 {
 960         struct idetape_bh *prev_bh, *bh, *merge_bh;
 961         int pages = tape->pages_per_buffer;
 962         unsigned int order, b_allocd;
 963         char *b_data = NULL;
 964
 965         merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
 966         bh = merge_bh;
 967         if (bh == NULL)
 968                 goto abort;
 969
 970         order = fls(pages) - 1;
 971         bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
 972         if (!bh->b_data)
 973                 goto abort;
 974         b_allocd = (1 << order) * PAGE_SIZE;
 975         pages &= (order-1);
 976
 977         if (clear)
 978                 memset(bh->b_data, 0, b_allocd);
 979         bh->b_reqnext = NULL;
 980         bh->b_size = b_allocd;
 981         atomic_set(&bh->b_count, full ? bh->b_size : 0);
 982
 983         while (pages) {
 984                 order = fls(pages) - 1;
 985                 b_data = (char *) __get_free_pages(GFP_KERNEL, order);
 986                 if (!b_data)
 987                         goto abort;
 988                 b_allocd = (1 << order) * PAGE_SIZE;
 989
 990                 if (clear)
 991                         memset(b_data, 0, b_allocd);
 992
 993                 /* newly allocated page frames below buffer header or ...*/
 994                 if (bh->b_data == b_data + b_allocd) {
 995                         bh->b_size += b_allocd;
 996                         bh->b_data -= b_allocd;
 997                         if (full)
 998                                 atomic_add(b_allocd, &bh->b_count);
 999                         continue;
1000                 }
1001                 /* they are above the header */
1002                 if (b_data == bh->b_data + bh->b_size) {
1003                         bh->b_size += b_allocd;
1004                         if (full)
1005                                 atomic_add(b_allocd, &bh->b_count);
1006                         continue;
1007                 }
1008                 prev_bh = bh;
1009                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1010                 if (!bh) {
1011                         free_pages((unsigned long) b_data, order);
1012                         goto abort;
1013                 }
1014                 bh->b_reqnext = NULL;
1015                 bh->b_data = b_data;
1016                 bh->b_size = b_allocd;
1017                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
1018                 prev_bh->b_reqnext = bh;
1019
1020                 pages &= (order-1);
1021         }
1022
1023         bh->b_size -= tape->excess_bh_size;
1024         if (full)
1025                 atomic_sub(tape->excess_bh_size, &bh->b_count);
1026         return merge_bh;
1027 abort:
1028         ide_tape_kfree_buffer(tape);
1029         return NULL;
1030 }
1031
1032 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
1033                                         const char __user *buf, int n)
1034 {
1035         struct idetape_bh *bh = tape->bh;
1036         int count;
1037         int ret = 0;
1038
1039         while (n) {
1040                 if (bh == NULL) {
1041                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1042                                         __func__);
1043                         return 1;
1044                 }
1045                 count = min((unsigned int)
1046                                 (bh->b_size - atomic_read(&bh->b_count)),
1047                                 (unsigned int)n);
1048                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
1049                                 count))
1050                         ret = 1;
1051                 n -= count;
1052                 atomic_add(count, &bh->b_count);
1053                 buf += count;
1054                 if (atomic_read(&bh->b_count) == bh->b_size) {
1055                         bh = bh->b_reqnext;
1056                         if (bh)
1057                                 atomic_set(&bh->b_count, 0);
1058                 }
1059         }
1060         tape->bh = bh;
1061         return ret;
1062 }
1063
1064 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1065                                       int n)
1066 {
1067         struct idetape_bh *bh = tape->bh;
1068         int count;
1069         int ret = 0;
1070
1071         while (n) {
1072                 if (bh == NULL) {
1073                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1074                                         __func__);
1075                         return 1;
1076                 }
1077                 count = min(tape->b_count, n);
1078                 if  (copy_to_user(buf, tape->b_data, count))
1079                         ret = 1;
1080                 n -= count;
1081                 tape->b_data += count;
1082                 tape->b_count -= count;
1083                 buf += count;
1084                 if (!tape->b_count) {
1085                         bh = bh->b_reqnext;
1086                         tape->bh = bh;
1087                         if (bh) {
1088                                 tape->b_data = bh->b_data;
1089                                 tape->b_count = atomic_read(&bh->b_count);
1090                         }
1091                 }
1092         }
1093         return ret;
1094 }
1095
1096 static void idetape_init_merge_buffer(idetape_tape_t *tape)
1097 {
1098         struct idetape_bh *bh = tape->merge_bh;
1099         tape->bh = tape->merge_bh;
1100
1101         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1102                 atomic_set(&bh->b_count, 0);
1103         else {
1104                 tape->b_data = bh->b_data;
1105                 tape->b_count = atomic_read(&bh->b_count);
1106         }
1107 }
1108
1109 /*
1110  * Write a filemark if write_filemark=1. Flush the device buffers without
1111  * writing a filemark otherwise.
1112  */
1113 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1114                 struct ide_atapi_pc *pc, int write_filemark)
1115 {
1116         ide_init_pc(pc);
1117         pc->c[0] = WRITE_FILEMARKS;
1118         pc->c[4] = write_filemark;
1119         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1120 }
1121
1122 static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
1123 {
1124         ide_init_pc(pc);
1125         pc->c[0] = TEST_UNIT_READY;
1126 }
1127
1128 static void idetape_create_load_unload_cmd(ide_drive_t *drive,
1129                 struct ide_atapi_pc *pc, int cmd)
1130 {
1131         ide_init_pc(pc);
1132         pc->c[0] = START_STOP;
1133         pc->c[4] = cmd;
1134         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1135 }
1136
1137 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1138 {
1139         idetape_tape_t *tape = drive->driver_data;
1140         struct gendisk *disk = tape->disk;
1141         struct ide_atapi_pc pc;
1142         int load_attempted = 0;
1143
1144         /* Wait for the tape to become ready */
1145         set_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1146         timeout += jiffies;
1147         while (time_before(jiffies, timeout)) {
1148                 idetape_create_test_unit_ready_cmd(&pc);
1149                 if (!ide_queue_pc_tail(drive, disk, &pc))
1150                         return 0;
1151                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1152                     || (tape->asc == 0x3A)) {
1153                         /* no media */
1154                         if (load_attempted)
1155                                 return -ENOMEDIUM;
1156                         idetape_create_load_unload_cmd(drive, &pc,
1157                                                         IDETAPE_LU_LOAD_MASK);
1158                         ide_queue_pc_tail(drive, disk, &pc);
1159                         load_attempted = 1;
1160                 /* not about to be ready */
1161                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1162                              (tape->ascq == 1 || tape->ascq == 8)))
1163                         return -EIO;
1164                 msleep(100);
1165         }
1166         return -EIO;
1167 }
1168
1169 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1170 {
1171         struct ide_tape_obj *tape = drive->driver_data;
1172         struct ide_atapi_pc pc;
1173         int rc;
1174
1175         idetape_create_write_filemark_cmd(drive, &pc, 0);
1176         rc = ide_queue_pc_tail(drive, tape->disk, &pc);
1177         if (rc)
1178                 return rc;
1179         idetape_wait_ready(drive, 60 * 5 * HZ);
1180         return 0;
1181 }
1182
1183 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1184 {
1185         ide_init_pc(pc);
1186         pc->c[0] = READ_POSITION;
1187         pc->req_xfer = 20;
1188 }
1189
1190 static int idetape_read_position(ide_drive_t *drive)
1191 {
1192         idetape_tape_t *tape = drive->driver_data;
1193         struct ide_atapi_pc pc;
1194         int position;
1195
1196         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1197
1198         idetape_create_read_position_cmd(&pc);
1199         if (ide_queue_pc_tail(drive, tape->disk, &pc))
1200                 return -1;
1201         position = tape->first_frame;
1202         return position;
1203 }
1204
1205 static void idetape_create_locate_cmd(ide_drive_t *drive,
1206                 struct ide_atapi_pc *pc,
1207                 unsigned int block, u8 partition, int skip)
1208 {
1209         ide_init_pc(pc);
1210         pc->c[0] = POSITION_TO_ELEMENT;
1211         pc->c[1] = 2;
1212         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
1213         pc->c[8] = partition;
1214         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1215 }
1216
1217 static int idetape_create_prevent_cmd(ide_drive_t *drive,
1218                 struct ide_atapi_pc *pc, int prevent)
1219 {
1220         idetape_tape_t *tape = drive->driver_data;
1221
1222         /* device supports locking according to capabilities page */
1223         if (!(tape->caps[6] & 0x01))
1224                 return 0;
1225
1226         ide_init_pc(pc);
1227         pc->c[0] = ALLOW_MEDIUM_REMOVAL;
1228         pc->c[4] = prevent;
1229         return 1;
1230 }
1231
1232 static int ide_tape_set_media_lock(ide_drive_t *drive, int on)
1233 {
1234         struct ide_tape_obj *tape = drive->driver_data;
1235         struct ide_atapi_pc pc;
1236
1237         if (!idetape_create_prevent_cmd(drive, &pc, on))
1238                 return 0;
1239
1240         return ide_queue_pc_tail(drive, tape->disk, &pc);
1241 }
1242
1243 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
1244 {
1245         idetape_tape_t *tape = drive->driver_data;
1246
1247         if (tape->chrdev_dir != IDETAPE_DIR_READ)
1248                 return;
1249
1250         clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
1251         tape->merge_bh_size = 0;
1252         if (tape->merge_bh != NULL) {
1253                 ide_tape_kfree_buffer(tape);
1254                 tape->merge_bh = NULL;
1255         }
1256
1257         tape->chrdev_dir = IDETAPE_DIR_NONE;
1258 }
1259
1260 /*
1261  * Position the tape to the requested block using the LOCATE packet command.
1262  * A READ POSITION command is then issued to check where we are positioned. Like
1263  * all higher level operations, we queue the commands at the tail of the request
1264  * queue and wait for their completion.
1265  */
1266 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
1267                 u8 partition, int skip)
1268 {
1269         idetape_tape_t *tape = drive->driver_data;
1270         struct gendisk *disk = tape->disk;
1271         int retval;
1272         struct ide_atapi_pc pc;
1273
1274         if (tape->chrdev_dir == IDETAPE_DIR_READ)
1275                 __ide_tape_discard_merge_buffer(drive);
1276         idetape_wait_ready(drive, 60 * 5 * HZ);
1277         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
1278         retval = ide_queue_pc_tail(drive, disk, &pc);
1279         if (retval)
1280                 return (retval);
1281
1282         idetape_create_read_position_cmd(&pc);
1283         return ide_queue_pc_tail(drive, disk, &pc);
1284 }
1285
1286 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
1287                                           int restore_position)
1288 {
1289         idetape_tape_t *tape = drive->driver_data;
1290         int seek, position;
1291
1292         __ide_tape_discard_merge_buffer(drive);
1293         if (restore_position) {
1294                 position = idetape_read_position(drive);
1295                 seek = position > 0 ? position : 0;
1296                 if (idetape_position_tape(drive, seek, 0, 0)) {
1297                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
1298                                          " %s\n", tape->name, __func__);
1299                         return;
1300                 }
1301         }
1302 }
1303
1304 /*
1305  * Generate a read/write request for the block device interface and wait for it
1306  * to be serviced.
1307  */
1308 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
1309                                  struct idetape_bh *bh)
1310 {
1311         idetape_tape_t *tape = drive->driver_data;
1312         struct request *rq;
1313         int ret, errors;
1314
1315         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
1316
1317         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
1318         rq->cmd_type = REQ_TYPE_SPECIAL;
1319         rq->cmd[13] = cmd;
1320         rq->rq_disk = tape->disk;
1321         rq->special = (void *)bh;
1322         rq->sector = tape->first_frame;
1323         rq->nr_sectors = blocks;
1324         rq->current_nr_sectors = blocks;
1325         blk_execute_rq(drive->queue, tape->disk, rq, 0);
1326
1327         errors = rq->errors;
1328         ret = tape->blk_size * (blocks - rq->current_nr_sectors);
1329         blk_put_request(rq);
1330
1331         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
1332                 return 0;
1333
1334         if (tape->merge_bh)
1335                 idetape_init_merge_buffer(tape);
1336         if (errors == IDETAPE_ERROR_GENERAL)
1337                 return -EIO;
1338         return ret;
1339 }
1340
1341 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
1342 {
1343         ide_init_pc(pc);
1344         pc->c[0] = INQUIRY;
1345         pc->c[4] = 254;
1346         pc->req_xfer = 254;
1347 }
1348
1349 static void idetape_create_rewind_cmd(ide_drive_t *drive,
1350                 struct ide_atapi_pc *pc)
1351 {
1352         ide_init_pc(pc);
1353         pc->c[0] = REZERO_UNIT;
1354         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1355 }
1356
1357 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
1358 {
1359         ide_init_pc(pc);
1360         pc->c[0] = ERASE;
1361         pc->c[1] = 1;
1362         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1363 }
1364
1365 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
1366 {
1367         ide_init_pc(pc);
1368         pc->c[0] = SPACE;
1369         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
1370         pc->c[1] = cmd;
1371         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1372 }
1373
1374 /* Queue up a character device originated write request. */
1375 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
1376 {
1377         idetape_tape_t *tape = drive->driver_data;
1378
1379         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1380
1381         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1382                                      blocks, tape->merge_bh);
1383 }
1384
1385 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
1386 {
1387         idetape_tape_t *tape = drive->driver_data;
1388         int blocks, min;
1389         struct idetape_bh *bh;
1390
1391         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1392                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
1393                                 " but we are not writing.\n");
1394                 return;
1395         }
1396         if (tape->merge_bh_size > tape->buffer_size) {
1397                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
1398                 tape->merge_bh_size = tape->buffer_size;
1399         }
1400         if (tape->merge_bh_size) {
1401                 blocks = tape->merge_bh_size / tape->blk_size;
1402                 if (tape->merge_bh_size % tape->blk_size) {
1403                         unsigned int i;
1404
1405                         blocks++;
1406                         i = tape->blk_size - tape->merge_bh_size %
1407                                 tape->blk_size;
1408                         bh = tape->bh->b_reqnext;
1409                         while (bh) {
1410                                 atomic_set(&bh->b_count, 0);
1411                                 bh = bh->b_reqnext;
1412                         }
1413                         bh = tape->bh;
1414                         while (i) {
1415                                 if (bh == NULL) {
1416                                         printk(KERN_INFO "ide-tape: bug,"
1417                                                          " bh NULL\n");
1418                                         break;
1419                                 }
1420                                 min = min(i, (unsigned int)(bh->b_size -
1421                                                 atomic_read(&bh->b_count)));
1422                                 memset(bh->b_data + atomic_read(&bh->b_count),
1423                                                 0, min);
1424                                 atomic_add(min, &bh->b_count);
1425                                 i -= min;
1426                                 bh = bh->b_reqnext;
1427                         }
1428                 }
1429                 (void) idetape_add_chrdev_write_request(drive, blocks);
1430                 tape->merge_bh_size = 0;
1431         }
1432         if (tape->merge_bh != NULL) {
1433                 ide_tape_kfree_buffer(tape);
1434                 tape->merge_bh = NULL;
1435         }
1436         tape->chrdev_dir = IDETAPE_DIR_NONE;
1437 }
1438
1439 static int idetape_init_read(ide_drive_t *drive)
1440 {
1441         idetape_tape_t *tape = drive->driver_data;
1442         int bytes_read;
1443
1444         /* Initialize read operation */
1445         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1446                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1447                         ide_tape_flush_merge_buffer(drive);
1448                         idetape_flush_tape_buffers(drive);
1449                 }
1450                 if (tape->merge_bh || tape->merge_bh_size) {
1451                         printk(KERN_ERR "ide-tape: merge_bh_size should be"
1452                                          " 0 now\n");
1453                         tape->merge_bh_size = 0;
1454                 }
1455                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1456                 if (!tape->merge_bh)
1457                         return -ENOMEM;
1458                 tape->chrdev_dir = IDETAPE_DIR_READ;
1459
1460                 /*
1461                  * Issue a read 0 command to ensure that DSC handshake is
1462                  * switched from completion mode to buffer available mode.
1463                  * No point in issuing this if DSC overlap isn't supported, some
1464                  * drives (Seagate STT3401A) will return an error.
1465                  */
1466                 if (drive->dsc_overlap) {
1467                         bytes_read = idetape_queue_rw_tail(drive,
1468                                                         REQ_IDETAPE_READ, 0,
1469                                                         tape->merge_bh);
1470                         if (bytes_read < 0) {
1471                                 ide_tape_kfree_buffer(tape);
1472                                 tape->merge_bh = NULL;
1473                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1474                                 return bytes_read;
1475                         }
1476                 }
1477         }
1478
1479         return 0;
1480 }
1481
1482 /* called from idetape_chrdev_read() to service a chrdev read request. */
1483 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
1484 {
1485         idetape_tape_t *tape = drive->driver_data;
1486
1487         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
1488
1489         /* If we are at a filemark, return a read length of 0 */
1490         if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1491                 return 0;
1492
1493         idetape_init_read(drive);
1494
1495         return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
1496                                      tape->merge_bh);
1497 }
1498
1499 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1500 {
1501         idetape_tape_t *tape = drive->driver_data;
1502         struct idetape_bh *bh;
1503         int blocks;
1504
1505         while (bcount) {
1506                 unsigned int count;
1507
1508                 bh = tape->merge_bh;
1509                 count = min(tape->buffer_size, bcount);
1510                 bcount -= count;
1511                 blocks = count / tape->blk_size;
1512                 while (count) {
1513                         atomic_set(&bh->b_count,
1514                                    min(count, (unsigned int)bh->b_size));
1515                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
1516                         count -= atomic_read(&bh->b_count);
1517                         bh = bh->b_reqnext;
1518                 }
1519                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
1520                                       tape->merge_bh);
1521         }
1522 }
1523
1524 /*
1525  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1526  * currently support only one partition.
1527  */
1528 static int idetape_rewind_tape(ide_drive_t *drive)
1529 {
1530         struct ide_tape_obj *tape = drive->driver_data;
1531         struct gendisk *disk = tape->disk;
1532         int retval;
1533         struct ide_atapi_pc pc;
1534
1535         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1536
1537         idetape_create_rewind_cmd(drive, &pc);
1538         retval = ide_queue_pc_tail(drive, disk, &pc);
1539         if (retval)
1540                 return retval;
1541
1542         idetape_create_read_position_cmd(&pc);
1543         retval = ide_queue_pc_tail(drive, disk, &pc);
1544         if (retval)
1545                 return retval;
1546         return 0;
1547 }
1548
1549 /* mtio.h compatible commands should be issued to the chrdev interface. */
1550 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1551                                 unsigned long arg)
1552 {
1553         idetape_tape_t *tape = drive->driver_data;
1554         void __user *argp = (void __user *)arg;
1555
1556         struct idetape_config {
1557                 int dsc_rw_frequency;
1558                 int dsc_media_access_frequency;
1559                 int nr_stages;
1560         } config;
1561
1562         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1563
1564         switch (cmd) {
1565         case 0x0340:
1566                 if (copy_from_user(&config, argp, sizeof(config)))
1567                         return -EFAULT;
1568                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1569                 break;
1570         case 0x0350:
1571                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1572                 config.nr_stages = 1;
1573                 if (copy_to_user(argp, &config, sizeof(config)))
1574                         return -EFAULT;
1575                 break;
1576         default:
1577                 return -EIO;
1578         }
1579         return 0;
1580 }
1581
1582 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1583                                         int mt_count)
1584 {
1585         idetape_tape_t *tape = drive->driver_data;
1586         struct gendisk *disk = tape->disk;
1587         struct ide_atapi_pc pc;
1588         int retval, count = 0;
1589         int sprev = !!(tape->caps[4] & 0x20);
1590
1591         if (mt_count == 0)
1592                 return 0;
1593         if (MTBSF == mt_op || MTBSFM == mt_op) {
1594                 if (!sprev)
1595                         return -EIO;
1596                 mt_count = -mt_count;
1597         }
1598
1599         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1600                 tape->merge_bh_size = 0;
1601                 if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
1602                         ++count;
1603                 ide_tape_discard_merge_buffer(drive, 0);
1604         }
1605
1606         switch (mt_op) {
1607         case MTFSF:
1608         case MTBSF:
1609                 idetape_create_space_cmd(&pc, mt_count - count,
1610                                          IDETAPE_SPACE_OVER_FILEMARK);
1611                 return ide_queue_pc_tail(drive, disk, &pc);
1612         case MTFSFM:
1613         case MTBSFM:
1614                 if (!sprev)
1615                         return -EIO;
1616                 retval = idetape_space_over_filemarks(drive, MTFSF,
1617                                                       mt_count - count);
1618                 if (retval)
1619                         return retval;
1620                 count = (MTBSFM == mt_op ? 1 : -1);
1621                 return idetape_space_over_filemarks(drive, MTFSF, count);
1622         default:
1623                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1624                                 mt_op);
1625                 return -EIO;
1626         }
1627 }
1628
1629 /*
1630  * Our character device read / write functions.
1631  *
1632  * The tape is optimized to maximize throughput when it is transferring an
1633  * integral number of the "continuous transfer limit", which is a parameter of
1634  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1635  *
1636  * As of version 1.3 of the driver, the character device provides an abstract
1637  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1638  * same backup/restore procedure is supported. The driver will internally
1639  * convert the requests to the recommended transfer unit, so that an unmatch
1640  * between the user's block size to the recommended size will only result in a
1641  * (slightly) increased driver overhead, but will no longer hit performance.
1642  * This is not applicable to Onstream.
1643  */
1644 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1645                                    size_t count, loff_t *ppos)
1646 {
1647         struct ide_tape_obj *tape = ide_tape_f(file);
1648         ide_drive_t *drive = tape->drive;
1649         ssize_t bytes_read, temp, actually_read = 0, rc;
1650         ssize_t ret = 0;
1651         u16 ctl = *(u16 *)&tape->caps[12];
1652
1653         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1654
1655         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1656                 if (test_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags))
1657                         if (count > tape->blk_size &&
1658                             (count % tape->blk_size) == 0)
1659                                 tape->user_bs_factor = count / tape->blk_size;
1660         }
1661         rc = idetape_init_read(drive);
1662         if (rc < 0)
1663                 return rc;
1664         if (count == 0)
1665                 return (0);
1666         if (tape->merge_bh_size) {
1667                 actually_read = min((unsigned int)(tape->merge_bh_size),
1668                                     (unsigned int)count);
1669                 if (idetape_copy_stage_to_user(tape, buf, actually_read))
1670                         ret = -EFAULT;
1671                 buf += actually_read;
1672                 tape->merge_bh_size -= actually_read;
1673                 count -= actually_read;
1674         }
1675         while (count >= tape->buffer_size) {
1676                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1677                 if (bytes_read <= 0)
1678                         goto finish;
1679                 if (idetape_copy_stage_to_user(tape, buf, bytes_read))
1680                         ret = -EFAULT;
1681                 buf += bytes_read;
1682                 count -= bytes_read;
1683                 actually_read += bytes_read;
1684         }
1685         if (count) {
1686                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
1687                 if (bytes_read <= 0)
1688                         goto finish;
1689                 temp = min((unsigned long)count, (unsigned long)bytes_read);
1690                 if (idetape_copy_stage_to_user(tape, buf, temp))
1691                         ret = -EFAULT;
1692                 actually_read += temp;
1693                 tape->merge_bh_size = bytes_read-temp;
1694         }
1695 finish:
1696         if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
1697                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1698
1699                 idetape_space_over_filemarks(drive, MTFSF, 1);
1700                 return 0;
1701         }
1702
1703         return ret ? ret : actually_read;
1704 }
1705
1706 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1707                                      size_t count, loff_t *ppos)
1708 {
1709         struct ide_tape_obj *tape = ide_tape_f(file);
1710         ide_drive_t *drive = tape->drive;
1711         ssize_t actually_written = 0;
1712         ssize_t ret = 0;
1713         u16 ctl = *(u16 *)&tape->caps[12];
1714
1715         /* The drive is write protected. */
1716         if (tape->write_prot)
1717                 return -EACCES;
1718
1719         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1720
1721         /* Initialize write operation */
1722         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
1723                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1724                         ide_tape_discard_merge_buffer(drive, 1);
1725                 if (tape->merge_bh || tape->merge_bh_size) {
1726                         printk(KERN_ERR "ide-tape: merge_bh_size "
1727                                 "should be 0 now\n");
1728                         tape->merge_bh_size = 0;
1729                 }
1730                 tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
1731                 if (!tape->merge_bh)
1732                         return -ENOMEM;
1733                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
1734                 idetape_init_merge_buffer(tape);
1735
1736                 /*
1737                  * Issue a write 0 command to ensure that DSC handshake is
1738                  * switched from completion mode to buffer available mode. No
1739                  * point in issuing this if DSC overlap isn't supported, some
1740                  * drives (Seagate STT3401A) will return an error.
1741                  */
1742                 if (drive->dsc_overlap) {
1743                         ssize_t retval = idetape_queue_rw_tail(drive,
1744                                                         REQ_IDETAPE_WRITE, 0,
1745                                                         tape->merge_bh);
1746                         if (retval < 0) {
1747                                 ide_tape_kfree_buffer(tape);
1748                                 tape->merge_bh = NULL;
1749                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
1750                                 return retval;
1751                         }
1752                 }
1753         }
1754         if (count == 0)
1755                 return (0);
1756         if (tape->merge_bh_size) {
1757                 if (tape->merge_bh_size >= tape->buffer_size) {
1758                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
1759                         tape->merge_bh_size = 0;
1760                 }
1761                 actually_written = min((unsigned int)
1762                                 (tape->buffer_size - tape->merge_bh_size),
1763                                 (unsigned int)count);
1764                 if (idetape_copy_stage_from_user(tape, buf, actually_written))
1765                                 ret = -EFAULT;
1766                 buf += actually_written;
1767                 tape->merge_bh_size += actually_written;
1768                 count -= actually_written;
1769
1770                 if (tape->merge_bh_size == tape->buffer_size) {
1771                         ssize_t retval;
1772                         tape->merge_bh_size = 0;
1773                         retval = idetape_add_chrdev_write_request(drive, ctl);
1774                         if (retval <= 0)
1775                                 return (retval);
1776                 }
1777         }
1778         while (count >= tape->buffer_size) {
1779                 ssize_t retval;
1780                 if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
1781                         ret = -EFAULT;
1782                 buf += tape->buffer_size;
1783                 count -= tape->buffer_size;
1784                 retval = idetape_add_chrdev_write_request(drive, ctl);
1785                 actually_written += tape->buffer_size;
1786                 if (retval <= 0)
1787                         return (retval);
1788         }
1789         if (count) {
1790                 actually_written += count;
1791                 if (idetape_copy_stage_from_user(tape, buf, count))
1792                         ret = -EFAULT;
1793                 tape->merge_bh_size += count;
1794         }
1795         return ret ? ret : actually_written;
1796 }
1797
1798 static int idetape_write_filemark(ide_drive_t *drive)
1799 {
1800         struct ide_tape_obj *tape = drive->driver_data;
1801         struct ide_atapi_pc pc;
1802
1803         /* Write a filemark */
1804         idetape_create_write_filemark_cmd(drive, &pc, 1);
1805         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
1806                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1807                 return -EIO;
1808         }
1809         return 0;
1810 }
1811
1812 /*
1813  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1814  * requested.
1815  *
1816  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1817  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1818  * usually not supported.
1819  *
1820  * The following commands are currently not supported:
1821  *
1822  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1823  * MT_ST_WRITE_THRESHOLD.
1824  */
1825 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1826 {
1827         idetape_tape_t *tape = drive->driver_data;
1828         struct gendisk *disk = tape->disk;
1829         struct ide_atapi_pc pc;
1830         int i, retval;
1831
1832         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1833                         mt_op, mt_count);
1834
1835         switch (mt_op) {
1836         case MTFSF:
1837         case MTFSFM:
1838         case MTBSF:
1839         case MTBSFM:
1840                 if (!mt_count)
1841                         return 0;
1842                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1843         default:
1844                 break;
1845         }
1846
1847         switch (mt_op) {
1848         case MTWEOF:
1849                 if (tape->write_prot)
1850                         return -EACCES;
1851                 ide_tape_discard_merge_buffer(drive, 1);
1852                 for (i = 0; i < mt_count; i++) {
1853                         retval = idetape_write_filemark(drive);
1854                         if (retval)
1855                                 return retval;
1856                 }
1857                 return 0;
1858         case MTREW:
1859                 ide_tape_discard_merge_buffer(drive, 0);
1860                 if (idetape_rewind_tape(drive))
1861                         return -EIO;
1862                 return 0;
1863         case MTLOAD:
1864                 ide_tape_discard_merge_buffer(drive, 0);
1865                 idetape_create_load_unload_cmd(drive, &pc,
1866                                                IDETAPE_LU_LOAD_MASK);
1867                 return ide_queue_pc_tail(drive, disk, &pc);
1868         case MTUNLOAD:
1869         case MTOFFL:
1870                 /*
1871                  * If door is locked, attempt to unlock before
1872                  * attempting to eject.
1873                  */
1874                 if (tape->door_locked) {
1875                         if (!ide_tape_set_media_lock(drive, 0))
1876                                 tape->door_locked = DOOR_UNLOCKED;
1877                 }
1878                 ide_tape_discard_merge_buffer(drive, 0);
1879                 idetape_create_load_unload_cmd(drive, &pc,
1880                                               !IDETAPE_LU_LOAD_MASK);
1881                 retval = ide_queue_pc_tail(drive, disk, &pc);
1882                 if (!retval)
1883                         clear_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags);
1884                 return retval;
1885         case MTNOP:
1886                 ide_tape_discard_merge_buffer(drive, 0);
1887                 return idetape_flush_tape_buffers(drive);
1888         case MTRETEN:
1889                 ide_tape_discard_merge_buffer(drive, 0);
1890                 idetape_create_load_unload_cmd(drive, &pc,
1891                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
1892                 return ide_queue_pc_tail(drive, disk, &pc);
1893         case MTEOM:
1894                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
1895                 return ide_queue_pc_tail(drive, disk, &pc);
1896         case MTERASE:
1897                 (void)idetape_rewind_tape(drive);
1898                 idetape_create_erase_cmd(&pc);
1899                 return ide_queue_pc_tail(drive, disk, &pc);
1900         case MTSETBLK:
1901                 if (mt_count) {
1902                         if (mt_count < tape->blk_size ||
1903                             mt_count % tape->blk_size)
1904                                 return -EIO;
1905                         tape->user_bs_factor = mt_count / tape->blk_size;
1906                         clear_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1907                 } else
1908                         set_bit(IDE_AFLAG_DETECT_BS, &drive->atapi_flags);
1909                 return 0;
1910         case MTSEEK:
1911                 ide_tape_discard_merge_buffer(drive, 0);
1912                 return idetape_position_tape(drive,
1913                         mt_count * tape->user_bs_factor, tape->partition, 0);
1914         case MTSETPART:
1915                 ide_tape_discard_merge_buffer(drive, 0);
1916                 return idetape_position_tape(drive, 0, mt_count, 0);
1917         case MTFSR:
1918         case MTBSR:
1919         case MTLOCK:
1920                 retval = ide_tape_set_media_lock(drive, 1);
1921                 if (retval)
1922                         return retval;
1923                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
1924                 return 0;
1925         case MTUNLOCK:
1926                 retval = ide_tape_set_media_lock(drive, 0);
1927                 if (retval)
1928                         return retval;
1929                 tape->door_locked = DOOR_UNLOCKED;
1930                 return 0;
1931         default:
1932                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1933                                 mt_op);
1934                 return -EIO;
1935         }
1936 }
1937
1938 /*
1939  * Our character device ioctls. General mtio.h magnetic io commands are
1940  * supported here, and not in the corresponding block interface. Our own
1941  * ide-tape ioctls are supported on both interfaces.
1942  */
1943 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
1944                                 unsigned int cmd, unsigned long arg)
1945 {
1946         struct ide_tape_obj *tape = ide_tape_f(file);
1947         ide_drive_t *drive = tape->drive;
1948         struct mtop mtop;
1949         struct mtget mtget;
1950         struct mtpos mtpos;
1951         int block_offset = 0, position = tape->first_frame;
1952         void __user *argp = (void __user *)arg;
1953
1954         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
1955
1956         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1957                 ide_tape_flush_merge_buffer(drive);
1958                 idetape_flush_tape_buffers(drive);
1959         }
1960         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
1961                 block_offset = tape->merge_bh_size /
1962                         (tape->blk_size * tape->user_bs_factor);
1963                 position = idetape_read_position(drive);
1964                 if (position < 0)
1965                         return -EIO;
1966         }
1967         switch (cmd) {
1968         case MTIOCTOP:
1969                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
1970                         return -EFAULT;
1971                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
1972         case MTIOCGET:
1973                 memset(&mtget, 0, sizeof(struct mtget));
1974                 mtget.mt_type = MT_ISSCSI2;
1975                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
1976                 mtget.mt_dsreg =
1977                         ((tape->blk_size * tape->user_bs_factor)
1978                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
1979
1980                 if (tape->drv_write_prot)
1981                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
1982
1983                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
1984                         return -EFAULT;
1985                 return 0;
1986         case MTIOCPOS:
1987                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
1988                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
1989                         return -EFAULT;
1990                 return 0;
1991         default:
1992                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1993                         ide_tape_discard_merge_buffer(drive, 1);
1994                 return idetape_blkdev_ioctl(drive, cmd, arg);
1995         }
1996 }
1997
1998 /*
1999  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
2000  * block size with the reported value.
2001  */
2002 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
2003 {
2004         idetape_tape_t *tape = drive->driver_data;
2005         struct ide_atapi_pc pc;
2006
2007         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
2008         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2009                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
2010                 if (tape->blk_size == 0) {
2011                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
2012                                             "block size, assuming 32k\n");
2013                         tape->blk_size = 32768;
2014                 }
2015                 return;
2016         }
2017         tape->blk_size = (pc.buf[4 + 5] << 16) +
2018                                 (pc.buf[4 + 6] << 8)  +
2019                                  pc.buf[4 + 7];
2020         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
2021 }
2022
2023 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
2024 {
2025         unsigned int minor = iminor(inode), i = minor & ~0xc0;
2026         ide_drive_t *drive;
2027         idetape_tape_t *tape;
2028         int retval;
2029
2030         if (i >= MAX_HWIFS * MAX_DRIVES)
2031                 return -ENXIO;
2032
2033         lock_kernel();
2034         tape = ide_tape_chrdev_get(i);
2035         if (!tape) {
2036                 unlock_kernel();
2037                 return -ENXIO;
2038         }
2039
2040         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2041
2042         /*
2043          * We really want to do nonseekable_open(inode, filp); here, but some
2044          * versions of tar incorrectly call lseek on tapes and bail out if that
2045          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
2046          */
2047         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
2048
2049         drive = tape->drive;
2050
2051         filp->private_data = tape;
2052
2053         if (test_and_set_bit(IDE_AFLAG_BUSY, &drive->atapi_flags)) {
2054                 retval = -EBUSY;
2055                 goto out_put_tape;
2056         }
2057
2058         retval = idetape_wait_ready(drive, 60 * HZ);
2059         if (retval) {
2060                 clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2061                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
2062                 goto out_put_tape;
2063         }
2064
2065         idetape_read_position(drive);
2066         if (!test_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags))
2067                 (void)idetape_rewind_tape(drive);
2068
2069         /* Read block size and write protect status from drive. */
2070         ide_tape_get_bsize_from_bdesc(drive);
2071
2072         /* Set write protect flag if device is opened as read-only. */
2073         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
2074                 tape->write_prot = 1;
2075         else
2076                 tape->write_prot = tape->drv_write_prot;
2077
2078         /* Make sure drive isn't write protected if user wants to write. */
2079         if (tape->write_prot) {
2080                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
2081                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
2082                         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2083                         retval = -EROFS;
2084                         goto out_put_tape;
2085                 }
2086         }
2087
2088         /* Lock the tape drive door so user can't eject. */
2089         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2090                 if (!ide_tape_set_media_lock(drive, 1)) {
2091                         if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
2092                                 tape->door_locked = DOOR_LOCKED;
2093                 }
2094         }
2095         unlock_kernel();
2096         return 0;
2097
2098 out_put_tape:
2099         ide_tape_put(tape);
2100         unlock_kernel();
2101         return retval;
2102 }
2103
2104 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
2105 {
2106         idetape_tape_t *tape = drive->driver_data;
2107
2108         ide_tape_flush_merge_buffer(drive);
2109         tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
2110         if (tape->merge_bh != NULL) {
2111                 idetape_pad_zeros(drive, tape->blk_size *
2112                                 (tape->user_bs_factor - 1));
2113                 ide_tape_kfree_buffer(tape);
2114                 tape->merge_bh = NULL;
2115         }
2116         idetape_write_filemark(drive);
2117         idetape_flush_tape_buffers(drive);
2118         idetape_flush_tape_buffers(drive);
2119 }
2120
2121 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
2122 {
2123         struct ide_tape_obj *tape = ide_tape_f(filp);
2124         ide_drive_t *drive = tape->drive;
2125         unsigned int minor = iminor(inode);
2126
2127         lock_kernel();
2128         tape = drive->driver_data;
2129
2130         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2131
2132         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
2133                 idetape_write_release(drive, minor);
2134         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2135                 if (minor < 128)
2136                         ide_tape_discard_merge_buffer(drive, 1);
2137         }
2138
2139         if (minor < 128 && test_bit(IDE_AFLAG_MEDIUM_PRESENT, &drive->atapi_flags))
2140                 (void) idetape_rewind_tape(drive);
2141         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
2142                 if (tape->door_locked == DOOR_LOCKED) {
2143                         if (!ide_tape_set_media_lock(drive, 0))
2144                                 tape->door_locked = DOOR_UNLOCKED;
2145                 }
2146         }
2147         clear_bit(IDE_AFLAG_BUSY, &drive->atapi_flags);
2148         ide_tape_put(tape);
2149         unlock_kernel();
2150         return 0;
2151 }
2152
2153 static void idetape_get_inquiry_results(ide_drive_t *drive)
2154 {
2155         idetape_tape_t *tape = drive->driver_data;
2156         struct ide_atapi_pc pc;
2157         char fw_rev[4], vendor_id[8], product_id[16];
2158
2159         idetape_create_inquiry_cmd(&pc);
2160         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2161                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
2162                                 tape->name);
2163                 return;
2164         }
2165         memcpy(vendor_id, &pc.buf[8], 8);
2166         memcpy(product_id, &pc.buf[16], 16);
2167         memcpy(fw_rev, &pc.buf[32], 4);
2168
2169         ide_fixstring(vendor_id, 8, 0);
2170         ide_fixstring(product_id, 16, 0);
2171         ide_fixstring(fw_rev, 4, 0);
2172
2173         printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
2174                         drive->name, tape->name, vendor_id, product_id, fw_rev);
2175 }
2176
2177 /*
2178  * Ask the tape about its various parameters. In particular, we will adjust our
2179  * data transfer buffer size to the recommended value as returned by the tape.
2180  */
2181 static void idetape_get_mode_sense_results(ide_drive_t *drive)
2182 {
2183         idetape_tape_t *tape = drive->driver_data;
2184         struct ide_atapi_pc pc;
2185         u8 *caps;
2186         u8 speed, max_speed;
2187
2188         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
2189         if (ide_queue_pc_tail(drive, tape->disk, &pc)) {
2190                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
2191                                 " some default values\n");
2192                 tape->blk_size = 512;
2193                 put_unaligned(52,   (u16 *)&tape->caps[12]);
2194                 put_unaligned(540,  (u16 *)&tape->caps[14]);
2195                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
2196                 return;
2197         }
2198         caps = pc.buf + 4 + pc.buf[3];
2199
2200         /* convert to host order and save for later use */
2201         speed = be16_to_cpup((__be16 *)&caps[14]);
2202         max_speed = be16_to_cpup((__be16 *)&caps[8]);
2203
2204         *(u16 *)&caps[8] = max_speed;
2205         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
2206         *(u16 *)&caps[14] = speed;
2207         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
2208
2209         if (!speed) {
2210                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
2211                                 "(assuming 650KB/sec)\n", drive->name);
2212                 *(u16 *)&caps[14] = 650;
2213         }
2214         if (!max_speed) {
2215                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
2216                                 "(assuming 650KB/sec)\n", drive->name);
2217                 *(u16 *)&caps[8] = 650;
2218         }
2219
2220         memcpy(&tape->caps, caps, 20);
2221         if (caps[7] & 0x02)
2222                 tape->blk_size = 512;
2223         else if (caps[7] & 0x04)
2224                 tape->blk_size = 1024;
2225 }
2226
2227 #ifdef CONFIG_IDE_PROC_FS
2228 #define ide_tape_devset_get(name, field) \
2229 static int get_##name(ide_drive_t *drive) \
2230 { \
2231         idetape_tape_t *tape = drive->driver_data; \
2232         return tape->field; \
2233 }
2234
2235 #define ide_tape_devset_set(name, field) \
2236 static int set_##name(ide_drive_t *drive, int arg) \
2237 { \
2238         idetape_tape_t *tape = drive->driver_data; \
2239         tape->field = arg; \
2240         return 0; \
2241 }
2242
2243 #define ide_tape_devset_rw(_name, _min, _max, _field, _mulf, _divf) \
2244 ide_tape_devset_get(_name, _field) \
2245 ide_tape_devset_set(_name, _field) \
2246 __IDE_DEVSET(_name, S_RW, _min, _max, get_##_name, set_##_name, _mulf, _divf)
2247
2248 #define ide_tape_devset_r(_name, _min, _max, _field, _mulf, _divf) \
2249 ide_tape_devset_get(_name, _field) \
2250 __IDE_DEVSET(_name, S_READ, _min, _max, get_##_name, NULL, _mulf, _divf)
2251
2252 static int mulf_tdsc(ide_drive_t *drive)        { return 1000; }
2253 static int divf_tdsc(ide_drive_t *drive)        { return   HZ; }
2254 static int divf_buffer(ide_drive_t *drive)      { return    2; }
2255 static int divf_buffer_size(ide_drive_t *drive) { return 1024; }
2256
2257 ide_devset_rw(dsc_overlap,      0,      1, dsc_overlap);
2258
2259 ide_tape_devset_rw(debug_mask,  0, 0xffff, debug_mask,  NULL, NULL);
2260 ide_tape_devset_rw(tdsc, IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
2261                    best_dsc_rw_freq, mulf_tdsc, divf_tdsc);
2262
2263 ide_tape_devset_r(avg_speed,    0, 0xffff, avg_speed,   NULL, NULL);
2264 ide_tape_devset_r(speed,        0, 0xffff, caps[14],    NULL, NULL);
2265 ide_tape_devset_r(buffer,       0, 0xffff, caps[16],    NULL, divf_buffer);
2266 ide_tape_devset_r(buffer_size,  0, 0xffff, buffer_size, NULL, divf_buffer_size);
2267
2268 static const struct ide_devset *idetape_settings[] = {
2269         &ide_devset_avg_speed,
2270         &ide_devset_buffer,
2271         &ide_devset_buffer_size,
2272         &ide_devset_debug_mask,
2273         &ide_devset_dsc_overlap,
2274         &ide_devset_speed,
2275         &ide_devset_tdsc,
2276         NULL
2277 };
2278 #endif
2279
2280 /*
2281  * The function below is called to:
2282  *
2283  * 1. Initialize our various state variables.
2284  * 2. Ask the tape for its capabilities.
2285  * 3. Allocate a buffer which will be used for data transfer. The buffer size
2286  * is chosen based on the recommendation which we received in step 2.
2287  *
2288  * Note that at this point ide.c already assigned us an irq, so that we can
2289  * queue requests here and wait for their completion.
2290  */
2291 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
2292 {
2293         unsigned long t;
2294         int speed;
2295         int buffer_size;
2296         u8 gcw[2];
2297         u16 *ctl = (u16 *)&tape->caps[12];
2298
2299         drive->pc_callback = ide_tape_callback;
2300
2301         spin_lock_init(&tape->lock);
2302         drive->dsc_overlap = 1;
2303         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
2304                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
2305                                  tape->name);
2306                 drive->dsc_overlap = 0;
2307         }
2308         /* Seagate Travan drives do not support DSC overlap. */
2309         if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
2310                 drive->dsc_overlap = 0;
2311         tape->minor = minor;
2312         tape->name[0] = 'h';
2313         tape->name[1] = 't';
2314         tape->name[2] = '0' + minor;
2315         tape->chrdev_dir = IDETAPE_DIR_NONE;
2316
2317         *((u16 *)&gcw) = drive->id[ATA_ID_CONFIG];
2318
2319         /* Command packet DRQ type */
2320         if (((gcw[0] & 0x60) >> 5) == 1)
2321                 set_bit(IDE_AFLAG_DRQ_INTERRUPT, &drive->atapi_flags);
2322
2323         idetape_get_inquiry_results(drive);
2324         idetape_get_mode_sense_results(drive);
2325         ide_tape_get_bsize_from_bdesc(drive);
2326         tape->user_bs_factor = 1;
2327         tape->buffer_size = *ctl * tape->blk_size;
2328         while (tape->buffer_size > 0xffff) {
2329                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
2330                 *ctl /= 2;
2331                 tape->buffer_size = *ctl * tape->blk_size;
2332         }
2333         buffer_size = tape->buffer_size;
2334         tape->pages_per_buffer = buffer_size / PAGE_SIZE;
2335         if (buffer_size % PAGE_SIZE) {
2336                 tape->pages_per_buffer++;
2337                 tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
2338         }
2339
2340         /* select the "best" DSC read/write polling freq */
2341         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
2342
2343         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
2344
2345         /*
2346          * Ensure that the number we got makes sense; limit it within
2347          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
2348          */
2349         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
2350                                          IDETAPE_DSC_RW_MAX);
2351         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
2352                 "%lums tDSC%s\n",
2353                 drive->name, tape->name, *(u16 *)&tape->caps[14],
2354                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
2355                 tape->buffer_size / 1024,
2356                 tape->best_dsc_rw_freq * 1000 / HZ,
2357                 drive->using_dma ? ", DMA":"");
2358
2359         ide_proc_register_driver(drive, tape->driver);
2360 }
2361
2362 static void ide_tape_remove(ide_drive_t *drive)
2363 {
2364         idetape_tape_t *tape = drive->driver_data;
2365
2366         ide_proc_unregister_driver(drive, tape->driver);
2367
2368         ide_unregister_region(tape->disk);
2369
2370         ide_tape_put(tape);
2371 }
2372
2373 static void ide_tape_release(struct kref *kref)
2374 {
2375         struct ide_tape_obj *tape = to_ide_tape(kref);
2376         ide_drive_t *drive = tape->drive;
2377         struct gendisk *g = tape->disk;
2378
2379         BUG_ON(tape->merge_bh_size);
2380
2381         drive->dsc_overlap = 0;
2382         drive->driver_data = NULL;
2383         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
2384         device_destroy(idetape_sysfs_class,
2385                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
2386         idetape_devs[tape->minor] = NULL;
2387         g->private_data = NULL;
2388         put_disk(g);
2389         kfree(tape);
2390 }
2391
2392 #ifdef CONFIG_IDE_PROC_FS
2393 static int proc_idetape_read_name
2394         (char *page, char **start, off_t off, int count, int *eof, void *data)
2395 {
2396         ide_drive_t     *drive = (ide_drive_t *) data;
2397         idetape_tape_t  *tape = drive->driver_data;
2398         char            *out = page;
2399         int             len;
2400
2401         len = sprintf(out, "%s\n", tape->name);
2402         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
2403 }
2404
2405 static ide_proc_entry_t idetape_proc[] = {
2406         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
2407         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
2408         { NULL, 0, NULL, NULL }
2409 };
2410 #endif
2411
2412 static int ide_tape_probe(ide_drive_t *);
2413
2414 static ide_driver_t idetape_driver = {
2415         .gen_driver = {
2416                 .owner          = THIS_MODULE,
2417                 .name           = "ide-tape",
2418                 .bus            = &ide_bus_type,
2419         },
2420         .probe                  = ide_tape_probe,
2421         .remove                 = ide_tape_remove,
2422         .version                = IDETAPE_VERSION,
2423         .media                  = ide_tape,
2424         .do_request             = idetape_do_request,
2425         .end_request            = idetape_end_request,
2426         .error                  = __ide_error,
2427 #ifdef CONFIG_IDE_PROC_FS
2428         .proc                   = idetape_proc,
2429         .settings               = idetape_settings,
2430 #endif
2431 };
2432
2433 /* Our character device supporting functions, passed to register_chrdev. */
2434 static const struct file_operations idetape_fops = {
2435         .owner          = THIS_MODULE,
2436         .read           = idetape_chrdev_read,
2437         .write          = idetape_chrdev_write,
2438         .ioctl          = idetape_chrdev_ioctl,
2439         .open           = idetape_chrdev_open,
2440         .release        = idetape_chrdev_release,
2441 };
2442
2443 static int idetape_open(struct inode *inode, struct file *filp)
2444 {
2445         struct gendisk *disk = inode->i_bdev->bd_disk;
2446         struct ide_tape_obj *tape;
2447
2448         tape = ide_tape_get(disk);
2449         if (!tape)
2450                 return -ENXIO;
2451
2452         return 0;
2453 }
2454
2455 static int idetape_release(struct inode *inode, struct file *filp)
2456 {
2457         struct gendisk *disk = inode->i_bdev->bd_disk;
2458         struct ide_tape_obj *tape = ide_tape_g(disk);
2459
2460         ide_tape_put(tape);
2461
2462         return 0;
2463 }
2464
2465 static int idetape_ioctl(struct inode *inode, struct file *file,
2466                         unsigned int cmd, unsigned long arg)
2467 {
2468         struct block_device *bdev = inode->i_bdev;
2469         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
2470         ide_drive_t *drive = tape->drive;
2471         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
2472         if (err == -EINVAL)
2473                 err = idetape_blkdev_ioctl(drive, cmd, arg);
2474         return err;
2475 }
2476
2477 static struct block_device_operations idetape_block_ops = {
2478         .owner          = THIS_MODULE,
2479         .open           = idetape_open,
2480         .release        = idetape_release,
2481         .ioctl          = idetape_ioctl,
2482 };
2483
2484 static int ide_tape_probe(ide_drive_t *drive)
2485 {
2486         idetape_tape_t *tape;
2487         struct gendisk *g;
2488         int minor;
2489
2490         if (!strstr("ide-tape", drive->driver_req))
2491                 goto failed;
2492
2493         if (drive->media != ide_tape)
2494                 goto failed;
2495
2496         if (drive->id_read == 1 && !ide_check_atapi_device(drive, DRV_NAME)) {
2497                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
2498                                 " the driver\n", drive->name);
2499                 goto failed;
2500         }
2501         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
2502         if (tape == NULL) {
2503                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
2504                                 drive->name);
2505                 goto failed;
2506         }
2507
2508         g = alloc_disk(1 << PARTN_BITS);
2509         if (!g)
2510                 goto out_free_tape;
2511
2512         ide_init_disk(g, drive);
2513
2514         kref_init(&tape->kref);
2515
2516         tape->drive = drive;
2517         tape->driver = &idetape_driver;
2518         tape->disk = g;
2519
2520         g->private_data = &tape->driver;
2521
2522         drive->driver_data = tape;
2523
2524         mutex_lock(&idetape_ref_mutex);
2525         for (minor = 0; idetape_devs[minor]; minor++)
2526                 ;
2527         idetape_devs[minor] = tape;
2528         mutex_unlock(&idetape_ref_mutex);
2529
2530         idetape_setup(drive, tape, minor);
2531
2532         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2533                               MKDEV(IDETAPE_MAJOR, minor), NULL,
2534                               "%s", tape->name);
2535         device_create_drvdata(idetape_sysfs_class, &drive->gendev,
2536                               MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
2537                               "n%s", tape->name);
2538
2539         g->fops = &idetape_block_ops;
2540         ide_register_region(g);
2541
2542         return 0;
2543
2544 out_free_tape:
2545         kfree(tape);
2546 failed:
2547         return -ENODEV;
2548 }
2549
2550 static void __exit idetape_exit(void)
2551 {
2552         driver_unregister(&idetape_driver.gen_driver);
2553         class_destroy(idetape_sysfs_class);
2554         unregister_chrdev(IDETAPE_MAJOR, "ht");
2555 }
2556
2557 static int __init idetape_init(void)
2558 {
2559         int error = 1;
2560         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2561         if (IS_ERR(idetape_sysfs_class)) {
2562                 idetape_sysfs_class = NULL;
2563                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2564                 error = -EBUSY;
2565                 goto out;
2566         }
2567
2568         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2569                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2570                                 " interface\n");
2571                 error = -EBUSY;
2572                 goto out_free_class;
2573         }
2574
2575         error = driver_register(&idetape_driver.gen_driver);
2576         if (error)
2577                 goto out_free_driver;
2578
2579         return 0;
2580
2581 out_free_driver:
2582         driver_unregister(&idetape_driver.gen_driver);
2583 out_free_class:
2584         class_destroy(idetape_sysfs_class);
2585 out:
2586         return error;
2587 }
2588
2589 MODULE_ALIAS("ide:*m-tape*");
2590 module_init(idetape_init);
2591 module_exit(idetape_exit);
2592 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2593 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2594 MODULE_LICENSE("GPL");