git.oblomov.eu Git - linux-2.6/blob - 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  * The following parameter is used to select the point in the internal tape fifo
  85  * in which we will start to refill the buffer. Decreasing the following
  86  * parameter will improve the system's latency and interactive response, while
  87  * using a high value might improve system throughput.
  88  */
  89 #define IDETAPE_FIFO_THRESHOLD          2
  90
  91 /*
  92  * DSC polling parameters.
  93  *
  94  * Polling for DSC (a single bit in the status register) is a very important
  95  * function in ide-tape. There are two cases in which we poll for DSC:
  96  *
  97  * 1. Before a read/write packet command, to ensure that we can transfer data
  98  * from/to the tape's data buffers, without causing an actual media access.
  99  * In case the tape is not ready yet, we take out our request from the device
 100  * request queue, so that ide.c could service requests from the other device
 101  * on the same interface in the meantime.
 102  *
 103  * 2. After the successful initialization of a "media access packet command",
 104  * which is a command that can take a long time to complete (the interval can
 105  * range from several seconds to even an hour). Again, we postpone our request
 106  * in the middle to free the bus for the other device. The polling frequency
 107  * here should be lower than the read/write frequency since those media access
 108  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
 109  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
 110  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
 111  *
 112  * We also set a timeout for the timer, in case something goes wrong. The
 113  * timeout should be longer then the maximum execution time of a tape operation.
 114  */
 115
 116 /* DSC timings. */
 117 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
 118 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
 119 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
 120 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
 121 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
 122 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
 123 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
 124
 125 /*************************** End of tunable parameters ***********************/
 126
 127 /* tape directions */
 128 enum {
 129         IDETAPE_DIR_NONE  = (1 << 0),
 130         IDETAPE_DIR_READ  = (1 << 1),
 131         IDETAPE_DIR_WRITE = (1 << 2),
 132 };
 133
 134 /* Tape door status */
 135 #define DOOR_UNLOCKED                   0
 136 #define DOOR_LOCKED                     1
 137 #define DOOR_EXPLICITLY_LOCKED          2
 138
 139 /* Some defines for the SPACE command */
 140 #define IDETAPE_SPACE_OVER_FILEMARK     1
 141 #define IDETAPE_SPACE_TO_EOD            3
 142
 143 /* Some defines for the LOAD UNLOAD command */
 144 #define IDETAPE_LU_LOAD_MASK            1
 145 #define IDETAPE_LU_RETENSION_MASK       2
 146 #define IDETAPE_LU_EOT_MASK             4
 147
 148 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
 149 #define IDETAPE_BLOCK_DESCRIPTOR        0
 150 #define IDETAPE_CAPABILITIES_PAGE       0x2a
 151
 152 /*
 153  * Most of our global data which we need to save even as we leave the driver due
 154  * to an interrupt or a timer event is stored in the struct defined below.
 155  */
 156 typedef struct ide_tape_obj {
 157         ide_drive_t             *drive;
 158         struct ide_driver       *driver;
 159         struct gendisk          *disk;
 160         struct device           dev;
 161
 162         /* used by REQ_IDETAPE_{READ,WRITE} requests */
 163         struct ide_atapi_pc queued_pc;
 164
 165         /*
 166          * DSC polling variables.
 167          *
 168          * While polling for DSC we use postponed_rq to postpone the current
 169          * request so that ide.c will be able to service pending requests on the
 170          * other device. Note that at most we will have only one DSC (usually
 171          * data transfer) request in the device request queue.
 172          */
 173         struct request *postponed_rq;
 174         /* The time in which we started polling for DSC */
 175         unsigned long dsc_polling_start;
 176         /* Timer used to poll for dsc */
 177         struct timer_list dsc_timer;
 178         /* Read/Write dsc polling frequency */
 179         unsigned long best_dsc_rw_freq;
 180         unsigned long dsc_poll_freq;
 181         unsigned long dsc_timeout;
 182
 183         /* Read position information */
 184         u8 partition;
 185         /* Current block */
 186         unsigned int first_frame;
 187
 188         /* Last error information */
 189         u8 sense_key, asc, ascq;
 190
 191         /* Character device operation */
 192         unsigned int minor;
 193         /* device name */
 194         char name[4];
 195         /* Current character device data transfer direction */
 196         u8 chrdev_dir;
 197
 198         /* tape block size, usually 512 or 1024 bytes */
 199         unsigned short blk_size;
 200         int user_bs_factor;
 201
 202         /* Copy of the tape's Capabilities and Mechanical Page */
 203         u8 caps[20];
 204
 205         /*
 206          * Active data transfer request parameters.
 207          *
 208          * At most, there is only one ide-tape originated data transfer request
 209          * in the device request queue. This allows ide.c to easily service
 210          * requests from the other device when we postpone our active request.
 211          */
 212
 213         /* Data buffer size chosen based on the tape's recommendation */
 214         int buffer_size;
 215         /* Staging buffer of buffer_size bytes */
 216         void *buf;
 217         /* The read/write cursor */
 218         void *cur;
 219         /* The number of valid bytes in buf */
 220         size_t valid;
 221
 222         /* Measures average tape speed */
 223         unsigned long avg_time;
 224         int avg_size;
 225         int avg_speed;
 226
 227         /* the door is currently locked */
 228         int door_locked;
 229         /* the tape hardware is write protected */
 230         char drv_write_prot;
 231         /* the tape is write protected (hardware or opened as read-only) */
 232         char write_prot;
 233
 234         u32 debug_mask;
 235 } idetape_tape_t;
 236
 237 static DEFINE_MUTEX(idetape_ref_mutex);
 238
 239 static struct class *idetape_sysfs_class;
 240
 241 static void ide_tape_release(struct device *);
 242
 243 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
 244
 245 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk, bool cdev,
 246                                          unsigned int i)
 247 {
 248         struct ide_tape_obj *tape = NULL;
 249
 250         mutex_lock(&idetape_ref_mutex);
 251
 252         if (cdev)
 253                 tape = idetape_devs[i];
 254         else
 255                 tape = ide_drv_g(disk, ide_tape_obj);
 256
 257         if (tape) {
 258                 if (ide_device_get(tape->drive))
 259                         tape = NULL;
 260                 else
 261                         get_device(&tape->dev);
 262         }
 263
 264         mutex_unlock(&idetape_ref_mutex);
 265         return tape;
 266 }
 267
 268 static void ide_tape_put(struct ide_tape_obj *tape)
 269 {
 270         ide_drive_t *drive = tape->drive;
 271
 272         mutex_lock(&idetape_ref_mutex);
 273         put_device(&tape->dev);
 274         ide_device_put(drive);
 275         mutex_unlock(&idetape_ref_mutex);
 276 }
 277
 278 /*
 279  * called on each failed packet command retry to analyze the request sense. We
 280  * currently do not utilize this information.
 281  */
 282 static void idetape_analyze_error(ide_drive_t *drive)
 283 {
 284         idetape_tape_t *tape = drive->driver_data;
 285         struct ide_atapi_pc *pc = drive->failed_pc;
 286         struct request *rq = drive->hwif->rq;
 287         u8 *sense = bio_data(rq->bio);
 288
 289         tape->sense_key = sense[2] & 0xF;
 290         tape->asc       = sense[12];
 291         tape->ascq      = sense[13];
 292
 293         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
 294                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
 295
 296         /* correct remaining bytes to transfer */
 297         if (pc->flags & PC_FLAG_DMA_ERROR)
 298                 rq->resid_len = tape->blk_size * get_unaligned_be32(&sense[3]);
 299
 300         /*
 301          * If error was the result of a zero-length read or write command,
 302          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
 303          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
 304          */
 305         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
 306             /* length == 0 */
 307             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
 308                 if (tape->sense_key == 5) {
 309                         /* don't report an error, everything's ok */
 310                         pc->error = 0;
 311                         /* don't retry read/write */
 312                         pc->flags |= PC_FLAG_ABORT;
 313                 }
 314         }
 315         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
 316                 pc->error = IDE_DRV_ERROR_FILEMARK;
 317                 pc->flags |= PC_FLAG_ABORT;
 318         }
 319         if (pc->c[0] == WRITE_6) {
 320                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
 321                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
 322                         pc->error = IDE_DRV_ERROR_EOD;
 323                         pc->flags |= PC_FLAG_ABORT;
 324                 }
 325         }
 326         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
 327                 if (tape->sense_key == 8) {
 328                         pc->error = IDE_DRV_ERROR_EOD;
 329                         pc->flags |= PC_FLAG_ABORT;
 330                 }
 331                 if (!(pc->flags & PC_FLAG_ABORT) &&
 332                     (blk_rq_bytes(rq) - rq->resid_len))
 333                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
 334         }
 335 }
 336
 337 static void ide_tape_handle_dsc(ide_drive_t *);
 338
 339 static int ide_tape_callback(ide_drive_t *drive, int dsc)
 340 {
 341         idetape_tape_t *tape = drive->driver_data;
 342         struct ide_atapi_pc *pc = drive->pc;
 343         struct request *rq = drive->hwif->rq;
 344         int uptodate = pc->error ? 0 : 1;
 345         int err = uptodate ? 0 : IDE_DRV_ERROR_GENERAL;
 346
 347         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 348
 349         if (dsc)
 350                 ide_tape_handle_dsc(drive);
 351
 352         if (drive->failed_pc == pc)
 353                 drive->failed_pc = NULL;
 354
 355         if (pc->c[0] == REQUEST_SENSE) {
 356                 if (uptodate)
 357                         idetape_analyze_error(drive);
 358                 else
 359                         printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
 360                                         "itself - Aborting request!\n");
 361         } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
 362                 unsigned int blocks =
 363                         (blk_rq_bytes(rq) - rq->resid_len) / tape->blk_size;
 364
 365                 tape->avg_size += blocks * tape->blk_size;
 366
 367                 if (time_after_eq(jiffies, tape->avg_time + HZ)) {
 368                         tape->avg_speed = tape->avg_size * HZ /
 369                                 (jiffies - tape->avg_time) / 1024;
 370                         tape->avg_size = 0;
 371                         tape->avg_time = jiffies;
 372                 }
 373
 374                 tape->first_frame += blocks;
 375
 376                 if (pc->error) {
 377                         uptodate = 0;
 378                         err = pc->error;
 379                 }
 380         }
 381         rq->errors = err;
 382
 383         return uptodate;
 384 }
 385
 386 /*
 387  * Postpone the current request so that ide.c will be able to service requests
 388  * from another device on the same port while we are polling for DSC.
 389  */
 390 static void idetape_postpone_request(ide_drive_t *drive)
 391 {
 392         idetape_tape_t *tape = drive->driver_data;
 393
 394         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 395
 396         tape->postponed_rq = drive->hwif->rq;
 397
 398         ide_stall_queue(drive, tape->dsc_poll_freq);
 399 }
 400
 401 static void ide_tape_handle_dsc(ide_drive_t *drive)
 402 {
 403         idetape_tape_t *tape = drive->driver_data;
 404
 405         /* Media access command */
 406         tape->dsc_polling_start = jiffies;
 407         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
 408         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
 409         /* Allow ide.c to handle other requests */
 410         idetape_postpone_request(drive);
 411 }
 412
 413 /*
 414  * Packet Command Interface
 415  *
 416  * The current Packet Command is available in drive->pc, and will not change
 417  * until we finish handling it. Each packet command is associated with a
 418  * callback function that will be called when the command is finished.
 419  *
 420  * The handling will be done in three stages:
 421  *
 422  * 1. ide_tape_issue_pc will send the packet command to the drive, and will set
 423  * the interrupt handler to ide_pc_intr.
 424  *
 425  * 2. On each interrupt, ide_pc_intr will be called. This step will be
 426  * repeated until the device signals us that no more interrupts will be issued.
 427  *
 428  * 3. ATAPI Tape media access commands have immediate status with a delayed
 429  * process. In case of a successful initiation of a media access packet command,
 430  * the DSC bit will be set when the actual execution of the command is finished.
 431  * Since the tape drive will not issue an interrupt, we have to poll for this
 432  * event. In this case, we define the request as "low priority request" by
 433  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
 434  * exit the driver.
 435  *
 436  * ide.c will then give higher priority to requests which originate from the
 437  * other device, until will change rq_status to RQ_ACTIVE.
 438  *
 439  * 4. When the packet command is finished, it will be checked for errors.
 440  *
 441  * 5. In case an error was found, we queue a request sense packet command in
 442  * front of the request queue and retry the operation up to
 443  * IDETAPE_MAX_PC_RETRIES times.
 444  *
 445  * 6. In case no error was found, or we decided to give up and not to retry
 446  * again, the callback function will be called and then we will handle the next
 447  * request.
 448  */
 449
 450 static ide_startstop_t ide_tape_issue_pc(ide_drive_t *drive,
 451                                          struct ide_cmd *cmd,
 452                                          struct ide_atapi_pc *pc)
 453 {
 454         idetape_tape_t *tape = drive->driver_data;
 455         struct request *rq = drive->hwif->rq;
 456
 457         if (drive->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
 458                 drive->failed_pc = pc;
 459
 460         /* Set the current packet command */
 461         drive->pc = pc;
 462
 463         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
 464                 (pc->flags & PC_FLAG_ABORT)) {
 465
 466                 /*
 467                  * We will "abort" retrying a packet command in case legitimate
 468                  * error code was received (crossing a filemark, or end of the
 469                  * media, for example).
 470                  */
 471                 if (!(pc->flags & PC_FLAG_ABORT)) {
 472                         if (!(pc->c[0] == TEST_UNIT_READY &&
 473                               tape->sense_key == 2 && tape->asc == 4 &&
 474                              (tape->ascq == 1 || tape->ascq == 8))) {
 475                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
 476                                                 "pc = %2x, key = %2x, "
 477                                                 "asc = %2x, ascq = %2x\n",
 478                                                 tape->name, pc->c[0],
 479                                                 tape->sense_key, tape->asc,
 480                                                 tape->ascq);
 481                         }
 482                         /* Giving up */
 483                         pc->error = IDE_DRV_ERROR_GENERAL;
 484                 }
 485
 486                 drive->failed_pc = NULL;
 487                 drive->pc_callback(drive, 0);
 488                 ide_complete_rq(drive, -EIO, blk_rq_bytes(rq));
 489                 return ide_stopped;
 490         }
 491         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
 492
 493         pc->retries++;
 494
 495         return ide_issue_pc(drive, cmd);
 496 }
 497
 498 /* A mode sense command is used to "sense" tape parameters. */
 499 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
 500 {
 501         ide_init_pc(pc);
 502         pc->c[0] = MODE_SENSE;
 503         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
 504                 /* DBD = 1 - Don't return block descriptors */
 505                 pc->c[1] = 8;
 506         pc->c[2] = page_code;
 507         /*
 508          * Changed pc->c[3] to 0 (255 will at best return unused info).
 509          *
 510          * For SCSI this byte is defined as subpage instead of high byte
 511          * of length and some IDE drives seem to interpret it this way
 512          * and return an error when 255 is used.
 513          */
 514         pc->c[3] = 0;
 515         /* We will just discard data in that case */
 516         pc->c[4] = 255;
 517         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
 518                 pc->req_xfer = 12;
 519         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
 520                 pc->req_xfer = 24;
 521         else
 522                 pc->req_xfer = 50;
 523 }
 524
 525 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
 526 {
 527         ide_hwif_t *hwif = drive->hwif;
 528         idetape_tape_t *tape = drive->driver_data;
 529         struct ide_atapi_pc *pc = drive->pc;
 530         u8 stat;
 531
 532         stat = hwif->tp_ops->read_status(hwif);
 533
 534         if (stat & ATA_DSC) {
 535                 if (stat & ATA_ERR) {
 536                         /* Error detected */
 537                         if (pc->c[0] != TEST_UNIT_READY)
 538                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
 539                                                 tape->name);
 540                         /* Retry operation */
 541                         ide_retry_pc(drive);
 542                         return ide_stopped;
 543                 }
 544                 pc->error = 0;
 545         } else {
 546                 pc->error = IDE_DRV_ERROR_GENERAL;
 547                 drive->failed_pc = NULL;
 548         }
 549         drive->pc_callback(drive, 0);
 550         return ide_stopped;
 551 }
 552
 553 static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
 554                                    struct ide_atapi_pc *pc, struct request *rq,
 555                                    u8 opcode)
 556 {
 557         unsigned int length = blk_rq_sectors(rq) / (tape->blk_size >> 9);
 558
 559         ide_init_pc(pc);
 560         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
 561         pc->c[1] = 1;
 562
 563         if (blk_rq_bytes(rq) == tape->buffer_size)
 564                 pc->flags |= PC_FLAG_DMA_OK;
 565
 566         if (opcode == READ_6)
 567                 pc->c[0] = READ_6;
 568         else if (opcode == WRITE_6) {
 569                 pc->c[0] = WRITE_6;
 570                 pc->flags |= PC_FLAG_WRITING;
 571         }
 572
 573         memcpy(rq->cmd, pc->c, 12);
 574 }
 575
 576 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 577                                           struct request *rq, sector_t block)
 578 {
 579         ide_hwif_t *hwif = drive->hwif;
 580         idetape_tape_t *tape = drive->driver_data;
 581         struct ide_atapi_pc *pc = NULL;
 582         struct request *postponed_rq = tape->postponed_rq;
 583         struct ide_cmd cmd;
 584         u8 stat;
 585
 586         debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %u\n"
 587                   (unsigned long long)blk_rq_pos(rq), blk_rq_sectors(rq));
 588
 589         BUG_ON(!(blk_special_request(rq) || blk_sense_request(rq)));
 590
 591         /* Retry a failed packet command */
 592         if (drive->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
 593                 pc = drive->failed_pc;
 594                 goto out;
 595         }
 596
 597         if (postponed_rq != NULL)
 598                 if (rq != postponed_rq) {
 599                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
 600                                         "Two DSC requests were queued\n");
 601                         drive->failed_pc = NULL;
 602                         rq->errors = 0;
 603                         ide_complete_rq(drive, 0, blk_rq_bytes(rq));
 604                         return ide_stopped;
 605                 }
 606
 607         tape->postponed_rq = NULL;
 608
 609         /*
 610          * If the tape is still busy, postpone our request and service
 611          * the other device meanwhile.
 612          */
 613         stat = hwif->tp_ops->read_status(hwif);
 614
 615         if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
 616             (rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
 617                 drive->atapi_flags |= IDE_AFLAG_IGNORE_DSC;
 618
 619         if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
 620                 drive->atapi_flags |= IDE_AFLAG_IGNORE_DSC;
 621                 drive->dev_flags &= ~IDE_DFLAG_POST_RESET;
 622         }
 623
 624         if (!(drive->atapi_flags & IDE_AFLAG_IGNORE_DSC) &&
 625             !(stat & ATA_DSC)) {
 626                 if (postponed_rq == NULL) {
 627                         tape->dsc_polling_start = jiffies;
 628                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
 629                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
 630                 } else if (time_after(jiffies, tape->dsc_timeout)) {
 631                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
 632                                 tape->name);
 633                         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
 634                                 idetape_media_access_finished(drive);
 635                                 return ide_stopped;
 636                         } else {
 637                                 return ide_do_reset(drive);
 638                         }
 639                 } else if (time_after(jiffies,
 640                                         tape->dsc_polling_start +
 641                                         IDETAPE_DSC_MA_THRESHOLD))
 642                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
 643                 idetape_postpone_request(drive);
 644                 return ide_stopped;
 645         } else
 646                 drive->atapi_flags &= ~IDE_AFLAG_IGNORE_DSC;
 647
 648         if (rq->cmd[13] & REQ_IDETAPE_READ) {
 649                 pc = &tape->queued_pc;
 650                 ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
 651                 goto out;
 652         }
 653         if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
 654                 pc = &tape->queued_pc;
 655                 ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
 656                 goto out;
 657         }
 658         if (rq->cmd[13] & REQ_IDETAPE_PC1) {
 659                 pc = (struct ide_atapi_pc *)rq->special;
 660                 rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
 661                 rq->cmd[13] |= REQ_IDETAPE_PC2;
 662                 goto out;
 663         }
 664         if (rq->cmd[13] & REQ_IDETAPE_PC2) {
 665                 idetape_media_access_finished(drive);
 666                 return ide_stopped;
 667         }
 668         BUG();
 669
 670 out:
 671         /* prepare sense request for this command */
 672         ide_prep_sense(drive, rq);
 673
 674         memset(&cmd, 0, sizeof(cmd));
 675
 676         if (rq_data_dir(rq))
 677                 cmd.tf_flags |= IDE_TFLAG_WRITE;
 678
 679         cmd.rq = rq;
 680
 681         ide_init_sg_cmd(&cmd, blk_rq_bytes(rq));
 682         ide_map_sg(drive, &cmd);
 683
 684         return ide_tape_issue_pc(drive, &cmd, pc);
 685 }
 686
 687 /*
 688  * Write a filemark if write_filemark=1. Flush the device buffers without
 689  * writing a filemark otherwise.
 690  */
 691 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
 692                 struct ide_atapi_pc *pc, int write_filemark)
 693 {
 694         ide_init_pc(pc);
 695         pc->c[0] = WRITE_FILEMARKS;
 696         pc->c[4] = write_filemark;
 697         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
 698 }
 699
 700 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
 701 {
 702         idetape_tape_t *tape = drive->driver_data;
 703         struct gendisk *disk = tape->disk;
 704         int load_attempted = 0;
 705
 706         /* Wait for the tape to become ready */
 707         set_bit(ilog2(IDE_AFLAG_MEDIUM_PRESENT), &drive->atapi_flags);
 708         timeout += jiffies;
 709         while (time_before(jiffies, timeout)) {
 710                 if (ide_do_test_unit_ready(drive, disk) == 0)
 711                         return 0;
 712                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
 713                     || (tape->asc == 0x3A)) {
 714                         /* no media */
 715                         if (load_attempted)
 716                                 return -ENOMEDIUM;
 717                         ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
 718                         load_attempted = 1;
 719                 /* not about to be ready */
 720                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
 721                              (tape->ascq == 1 || tape->ascq == 8)))
 722                         return -EIO;
 723                 msleep(100);
 724         }
 725         return -EIO;
 726 }
 727
 728 static int idetape_flush_tape_buffers(ide_drive_t *drive)
 729 {
 730         struct ide_tape_obj *tape = drive->driver_data;
 731         struct ide_atapi_pc pc;
 732         int rc;
 733
 734         idetape_create_write_filemark_cmd(drive, &pc, 0);
 735         rc = ide_queue_pc_tail(drive, tape->disk, &pc, NULL, 0);
 736         if (rc)
 737                 return rc;
 738         idetape_wait_ready(drive, 60 * 5 * HZ);
 739         return 0;
 740 }
 741
 742 static int ide_tape_read_position(ide_drive_t *drive)
 743 {
 744         idetape_tape_t *tape = drive->driver_data;
 745         struct ide_atapi_pc pc;
 746         u8 buf[20];
 747
 748         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 749
 750         /* prep cmd */
 751         ide_init_pc(&pc);
 752         pc.c[0] = READ_POSITION;
 753         pc.req_xfer = 20;
 754
 755         if (ide_queue_pc_tail(drive, tape->disk, &pc, buf, pc.req_xfer))
 756                 return -1;
 757
 758         if (!pc.error) {
 759                 debug_log(DBG_SENSE, "BOP - %s\n",
 760                                 (buf[0] & 0x80) ? "Yes" : "No");
 761                 debug_log(DBG_SENSE, "EOP - %s\n",
 762                                 (buf[0] & 0x40) ? "Yes" : "No");
 763
 764                 if (buf[0] & 0x4) {
 765                         printk(KERN_INFO "ide-tape: Block location is unknown"
 766                                          "to the tape\n");
 767                         clear_bit(ilog2(IDE_AFLAG_ADDRESS_VALID),
 768                                   &drive->atapi_flags);
 769                         return -1;
 770                 } else {
 771                         debug_log(DBG_SENSE, "Block Location - %u\n",
 772                                         be32_to_cpup((__be32 *)&buf[4]));
 773
 774                         tape->partition = buf[1];
 775                         tape->first_frame = be32_to_cpup((__be32 *)&buf[4]);
 776                         set_bit(ilog2(IDE_AFLAG_ADDRESS_VALID),
 777                                 &drive->atapi_flags);
 778                 }
 779         }
 780
 781         return tape->first_frame;
 782 }
 783
 784 static void idetape_create_locate_cmd(ide_drive_t *drive,
 785                 struct ide_atapi_pc *pc,
 786                 unsigned int block, u8 partition, int skip)
 787 {
 788         ide_init_pc(pc);
 789         pc->c[0] = POSITION_TO_ELEMENT;
 790         pc->c[1] = 2;
 791         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
 792         pc->c[8] = partition;
 793         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
 794 }
 795
 796 static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
 797 {
 798         idetape_tape_t *tape = drive->driver_data;
 799
 800         if (tape->chrdev_dir != IDETAPE_DIR_READ)
 801                 return;
 802
 803         clear_bit(ilog2(IDE_AFLAG_FILEMARK), &drive->atapi_flags);
 804         tape->valid = 0;
 805         if (tape->buf != NULL) {
 806                 kfree(tape->buf);
 807                 tape->buf = NULL;
 808         }
 809
 810         tape->chrdev_dir = IDETAPE_DIR_NONE;
 811 }
 812
 813 /*
 814  * Position the tape to the requested block using the LOCATE packet command.
 815  * A READ POSITION command is then issued to check where we are positioned. Like
 816  * all higher level operations, we queue the commands at the tail of the request
 817  * queue and wait for their completion.
 818  */
 819 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
 820                 u8 partition, int skip)
 821 {
 822         idetape_tape_t *tape = drive->driver_data;
 823         struct gendisk *disk = tape->disk;
 824         int ret;
 825         struct ide_atapi_pc pc;
 826
 827         if (tape->chrdev_dir == IDETAPE_DIR_READ)
 828                 __ide_tape_discard_merge_buffer(drive);
 829         idetape_wait_ready(drive, 60 * 5 * HZ);
 830         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
 831         ret = ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
 832         if (ret)
 833                 return ret;
 834
 835         ret = ide_tape_read_position(drive);
 836         if (ret < 0)
 837                 return ret;
 838         return 0;
 839 }
 840
 841 static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
 842                                           int restore_position)
 843 {
 844         idetape_tape_t *tape = drive->driver_data;
 845         int seek, position;
 846
 847         __ide_tape_discard_merge_buffer(drive);
 848         if (restore_position) {
 849                 position = ide_tape_read_position(drive);
 850                 seek = position > 0 ? position : 0;
 851                 if (idetape_position_tape(drive, seek, 0, 0)) {
 852                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
 853                                          " %s\n", tape->name, __func__);
 854                         return;
 855                 }
 856         }
 857 }
 858
 859 /*
 860  * Generate a read/write request for the block device interface and wait for it
 861  * to be serviced.
 862  */
 863 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int size)
 864 {
 865         idetape_tape_t *tape = drive->driver_data;
 866         struct request *rq;
 867         int ret;
 868
 869         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
 870         BUG_ON(cmd != REQ_IDETAPE_READ && cmd != REQ_IDETAPE_WRITE);
 871         BUG_ON(size < 0 || size % tape->blk_size);
 872
 873         rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
 874         rq->cmd_type = REQ_TYPE_SPECIAL;
 875         rq->cmd[13] = cmd;
 876         rq->rq_disk = tape->disk;
 877         rq->__sector = tape->first_frame;
 878
 879         if (size) {
 880                 ret = blk_rq_map_kern(drive->queue, rq, tape->buf, size,
 881                                       __GFP_WAIT);
 882                 if (ret)
 883                         goto out_put;
 884         }
 885
 886         blk_execute_rq(drive->queue, tape->disk, rq, 0);
 887
 888         /* calculate the number of transferred bytes and update buffer state */
 889         size -= rq->resid_len;
 890         tape->cur = tape->buf;
 891         if (cmd == REQ_IDETAPE_READ)
 892                 tape->valid = size;
 893         else
 894                 tape->valid = 0;
 895
 896         ret = size;
 897         if (rq->errors == IDE_DRV_ERROR_GENERAL)
 898                 ret = -EIO;
 899 out_put:
 900         blk_put_request(rq);
 901         return ret;
 902 }
 903
 904 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
 905 {
 906         ide_init_pc(pc);
 907         pc->c[0] = INQUIRY;
 908         pc->c[4] = 254;
 909         pc->req_xfer = 254;
 910 }
 911
 912 static void idetape_create_rewind_cmd(ide_drive_t *drive,
 913                 struct ide_atapi_pc *pc)
 914 {
 915         ide_init_pc(pc);
 916         pc->c[0] = REZERO_UNIT;
 917         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
 918 }
 919
 920 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
 921 {
 922         ide_init_pc(pc);
 923         pc->c[0] = ERASE;
 924         pc->c[1] = 1;
 925         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
 926 }
 927
 928 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
 929 {
 930         ide_init_pc(pc);
 931         pc->c[0] = SPACE;
 932         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
 933         pc->c[1] = cmd;
 934         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
 935 }
 936
 937 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
 938 {
 939         idetape_tape_t *tape = drive->driver_data;
 940
 941         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
 942                 printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
 943                                 " but we are not writing.\n");
 944                 return;
 945         }
 946         if (tape->buf) {
 947                 size_t aligned = roundup(tape->valid, tape->blk_size);
 948
 949                 memset(tape->cur, 0, aligned - tape->valid);
 950                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, aligned);
 951                 kfree(tape->buf);
 952                 tape->buf = NULL;
 953         }
 954         tape->chrdev_dir = IDETAPE_DIR_NONE;
 955 }
 956
 957 static int idetape_init_rw(ide_drive_t *drive, int dir)
 958 {
 959         idetape_tape_t *tape = drive->driver_data;
 960         int rc;
 961
 962         BUG_ON(dir != IDETAPE_DIR_READ && dir != IDETAPE_DIR_WRITE);
 963
 964         if (tape->chrdev_dir == dir)
 965                 return 0;
 966
 967         if (tape->chrdev_dir == IDETAPE_DIR_READ)
 968                 ide_tape_discard_merge_buffer(drive, 1);
 969         else if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
 970                 ide_tape_flush_merge_buffer(drive);
 971                 idetape_flush_tape_buffers(drive);
 972         }
 973
 974         if (tape->buf || tape->valid) {
 975                 printk(KERN_ERR "ide-tape: valid should be 0 now\n");
 976                 tape->valid = 0;
 977         }
 978
 979         tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL);
 980         if (!tape->buf)
 981                 return -ENOMEM;
 982         tape->chrdev_dir = dir;
 983         tape->cur = tape->buf;
 984
 985         /*
 986          * Issue a 0 rw command to ensure that DSC handshake is
 987          * switched from completion mode to buffer available mode.  No
 988          * point in issuing this if DSC overlap isn't supported, some
 989          * drives (Seagate STT3401A) will return an error.
 990          */
 991         if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
 992                 int cmd = dir == IDETAPE_DIR_READ ? REQ_IDETAPE_READ
 993                                                   : REQ_IDETAPE_WRITE;
 994
 995                 rc = idetape_queue_rw_tail(drive, cmd, 0);
 996                 if (rc < 0) {
 997                         kfree(tape->buf);
 998                         tape->buf = NULL;
 999                         tape->chrdev_dir = IDETAPE_DIR_NONE;
1000                         return rc;
1001                 }
1002         }
1003
1004         return 0;
1005 }
1006
1007 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
1008 {
1009         idetape_tape_t *tape = drive->driver_data;
1010
1011         memset(tape->buf, 0, tape->buffer_size);
1012
1013         while (bcount) {
1014                 unsigned int count = min(tape->buffer_size, bcount);
1015
1016                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, count);
1017                 bcount -= count;
1018         }
1019 }
1020
1021 /*
1022  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
1023  * currently support only one partition.
1024  */
1025 static int idetape_rewind_tape(ide_drive_t *drive)
1026 {
1027         struct ide_tape_obj *tape = drive->driver_data;
1028         struct gendisk *disk = tape->disk;
1029         struct ide_atapi_pc pc;
1030         int ret;
1031
1032         debug_log(DBG_SENSE, "Enter %s\n", __func__);
1033
1034         idetape_create_rewind_cmd(drive, &pc);
1035         ret = ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
1036         if (ret)
1037                 return ret;
1038
1039         ret = ide_tape_read_position(drive);
1040         if (ret < 0)
1041                 return ret;
1042         return 0;
1043 }
1044
1045 /* mtio.h compatible commands should be issued to the chrdev interface. */
1046 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
1047                                 unsigned long arg)
1048 {
1049         idetape_tape_t *tape = drive->driver_data;
1050         void __user *argp = (void __user *)arg;
1051
1052         struct idetape_config {
1053                 int dsc_rw_frequency;
1054                 int dsc_media_access_frequency;
1055                 int nr_stages;
1056         } config;
1057
1058         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1059
1060         switch (cmd) {
1061         case 0x0340:
1062                 if (copy_from_user(&config, argp, sizeof(config)))
1063                         return -EFAULT;
1064                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
1065                 break;
1066         case 0x0350:
1067                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
1068                 config.nr_stages = 1;
1069                 if (copy_to_user(argp, &config, sizeof(config)))
1070                         return -EFAULT;
1071                 break;
1072         default:
1073                 return -EIO;
1074         }
1075         return 0;
1076 }
1077
1078 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
1079                                         int mt_count)
1080 {
1081         idetape_tape_t *tape = drive->driver_data;
1082         struct gendisk *disk = tape->disk;
1083         struct ide_atapi_pc pc;
1084         int retval, count = 0;
1085         int sprev = !!(tape->caps[4] & 0x20);
1086
1087         if (mt_count == 0)
1088                 return 0;
1089         if (MTBSF == mt_op || MTBSFM == mt_op) {
1090                 if (!sprev)
1091                         return -EIO;
1092                 mt_count = -mt_count;
1093         }
1094
1095         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1096                 tape->valid = 0;
1097                 if (test_and_clear_bit(ilog2(IDE_AFLAG_FILEMARK),
1098                                        &drive->atapi_flags))
1099                         ++count;
1100                 ide_tape_discard_merge_buffer(drive, 0);
1101         }
1102
1103         switch (mt_op) {
1104         case MTFSF:
1105         case MTBSF:
1106                 idetape_create_space_cmd(&pc, mt_count - count,
1107                                          IDETAPE_SPACE_OVER_FILEMARK);
1108                 return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
1109         case MTFSFM:
1110         case MTBSFM:
1111                 if (!sprev)
1112                         return -EIO;
1113                 retval = idetape_space_over_filemarks(drive, MTFSF,
1114                                                       mt_count - count);
1115                 if (retval)
1116                         return retval;
1117                 count = (MTBSFM == mt_op ? 1 : -1);
1118                 return idetape_space_over_filemarks(drive, MTFSF, count);
1119         default:
1120                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1121                                 mt_op);
1122                 return -EIO;
1123         }
1124 }
1125
1126 /*
1127  * Our character device read / write functions.
1128  *
1129  * The tape is optimized to maximize throughput when it is transferring an
1130  * integral number of the "continuous transfer limit", which is a parameter of
1131  * the specific tape (26kB on my particular tape, 32kB for Onstream).
1132  *
1133  * As of version 1.3 of the driver, the character device provides an abstract
1134  * continuous view of the media - any mix of block sizes (even 1 byte) on the
1135  * same backup/restore procedure is supported. The driver will internally
1136  * convert the requests to the recommended transfer unit, so that an unmatch
1137  * between the user's block size to the recommended size will only result in a
1138  * (slightly) increased driver overhead, but will no longer hit performance.
1139  * This is not applicable to Onstream.
1140  */
1141 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
1142                                    size_t count, loff_t *ppos)
1143 {
1144         struct ide_tape_obj *tape = file->private_data;
1145         ide_drive_t *drive = tape->drive;
1146         size_t done = 0;
1147         ssize_t ret = 0;
1148         int rc;
1149
1150         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1151
1152         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
1153                 if (test_bit(ilog2(IDE_AFLAG_DETECT_BS), &drive->atapi_flags))
1154                         if (count > tape->blk_size &&
1155                             (count % tape->blk_size) == 0)
1156                                 tape->user_bs_factor = count / tape->blk_size;
1157         }
1158
1159         rc = idetape_init_rw(drive, IDETAPE_DIR_READ);
1160         if (rc < 0)
1161                 return rc;
1162
1163         while (done < count) {
1164                 size_t todo;
1165
1166                 /* refill if staging buffer is empty */
1167                 if (!tape->valid) {
1168                         /* If we are at a filemark, nothing more to read */
1169                         if (test_bit(ilog2(IDE_AFLAG_FILEMARK),
1170                                      &drive->atapi_flags))
1171                                 break;
1172                         /* read */
1173                         if (idetape_queue_rw_tail(drive, REQ_IDETAPE_READ,
1174                                                   tape->buffer_size) <= 0)
1175                                 break;
1176                 }
1177
1178                 /* copy out */
1179                 todo = min_t(size_t, count - done, tape->valid);
1180                 if (copy_to_user(buf + done, tape->cur, todo))
1181                         ret = -EFAULT;
1182
1183                 tape->cur += todo;
1184                 tape->valid -= todo;
1185                 done += todo;
1186         }
1187
1188         if (!done && test_bit(ilog2(IDE_AFLAG_FILEMARK), &drive->atapi_flags)) {
1189                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
1190
1191                 idetape_space_over_filemarks(drive, MTFSF, 1);
1192                 return 0;
1193         }
1194
1195         return ret ? ret : done;
1196 }
1197
1198 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
1199                                      size_t count, loff_t *ppos)
1200 {
1201         struct ide_tape_obj *tape = file->private_data;
1202         ide_drive_t *drive = tape->drive;
1203         size_t done = 0;
1204         ssize_t ret = 0;
1205         int rc;
1206
1207         /* The drive is write protected. */
1208         if (tape->write_prot)
1209                 return -EACCES;
1210
1211         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
1212
1213         /* Initialize write operation */
1214         rc = idetape_init_rw(drive, IDETAPE_DIR_WRITE);
1215         if (rc < 0)
1216                 return rc;
1217
1218         while (done < count) {
1219                 size_t todo;
1220
1221                 /* flush if staging buffer is full */
1222                 if (tape->valid == tape->buffer_size &&
1223                     idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
1224                                           tape->buffer_size) <= 0)
1225                         return rc;
1226
1227                 /* copy in */
1228                 todo = min_t(size_t, count - done,
1229                              tape->buffer_size - tape->valid);
1230                 if (copy_from_user(tape->cur, buf + done, todo))
1231                         ret = -EFAULT;
1232
1233                 tape->cur += todo;
1234                 tape->valid += todo;
1235                 done += todo;
1236         }
1237
1238         return ret ? ret : done;
1239 }
1240
1241 static int idetape_write_filemark(ide_drive_t *drive)
1242 {
1243         struct ide_tape_obj *tape = drive->driver_data;
1244         struct ide_atapi_pc pc;
1245
1246         /* Write a filemark */
1247         idetape_create_write_filemark_cmd(drive, &pc, 1);
1248         if (ide_queue_pc_tail(drive, tape->disk, &pc, NULL, 0)) {
1249                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
1250                 return -EIO;
1251         }
1252         return 0;
1253 }
1254
1255 /*
1256  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
1257  * requested.
1258  *
1259  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
1260  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
1261  * usually not supported.
1262  *
1263  * The following commands are currently not supported:
1264  *
1265  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
1266  * MT_ST_WRITE_THRESHOLD.
1267  */
1268 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
1269 {
1270         idetape_tape_t *tape = drive->driver_data;
1271         struct gendisk *disk = tape->disk;
1272         struct ide_atapi_pc pc;
1273         int i, retval;
1274
1275         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
1276                         mt_op, mt_count);
1277
1278         switch (mt_op) {
1279         case MTFSF:
1280         case MTFSFM:
1281         case MTBSF:
1282         case MTBSFM:
1283                 if (!mt_count)
1284                         return 0;
1285                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
1286         default:
1287                 break;
1288         }
1289
1290         switch (mt_op) {
1291         case MTWEOF:
1292                 if (tape->write_prot)
1293                         return -EACCES;
1294                 ide_tape_discard_merge_buffer(drive, 1);
1295                 for (i = 0; i < mt_count; i++) {
1296                         retval = idetape_write_filemark(drive);
1297                         if (retval)
1298                                 return retval;
1299                 }
1300                 return 0;
1301         case MTREW:
1302                 ide_tape_discard_merge_buffer(drive, 0);
1303                 if (idetape_rewind_tape(drive))
1304                         return -EIO;
1305                 return 0;
1306         case MTLOAD:
1307                 ide_tape_discard_merge_buffer(drive, 0);
1308                 return ide_do_start_stop(drive, disk, IDETAPE_LU_LOAD_MASK);
1309         case MTUNLOAD:
1310         case MTOFFL:
1311                 /*
1312                  * If door is locked, attempt to unlock before
1313                  * attempting to eject.
1314                  */
1315                 if (tape->door_locked) {
1316                         if (!ide_set_media_lock(drive, disk, 0))
1317                                 tape->door_locked = DOOR_UNLOCKED;
1318                 }
1319                 ide_tape_discard_merge_buffer(drive, 0);
1320                 retval = ide_do_start_stop(drive, disk, !IDETAPE_LU_LOAD_MASK);
1321                 if (!retval)
1322                         clear_bit(ilog2(IDE_AFLAG_MEDIUM_PRESENT),
1323                                   &drive->atapi_flags);
1324                 return retval;
1325         case MTNOP:
1326                 ide_tape_discard_merge_buffer(drive, 0);
1327                 return idetape_flush_tape_buffers(drive);
1328         case MTRETEN:
1329                 ide_tape_discard_merge_buffer(drive, 0);
1330                 return ide_do_start_stop(drive, disk,
1331                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
1332         case MTEOM:
1333                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
1334                 return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
1335         case MTERASE:
1336                 (void)idetape_rewind_tape(drive);
1337                 idetape_create_erase_cmd(&pc);
1338                 return ide_queue_pc_tail(drive, disk, &pc, NULL, 0);
1339         case MTSETBLK:
1340                 if (mt_count) {
1341                         if (mt_count < tape->blk_size ||
1342                             mt_count % tape->blk_size)
1343                                 return -EIO;
1344                         tape->user_bs_factor = mt_count / tape->blk_size;
1345                         clear_bit(ilog2(IDE_AFLAG_DETECT_BS),
1346                                   &drive->atapi_flags);
1347                 } else
1348                         set_bit(ilog2(IDE_AFLAG_DETECT_BS),
1349                                 &drive->atapi_flags);
1350                 return 0;
1351         case MTSEEK:
1352                 ide_tape_discard_merge_buffer(drive, 0);
1353                 return idetape_position_tape(drive,
1354                         mt_count * tape->user_bs_factor, tape->partition, 0);
1355         case MTSETPART:
1356                 ide_tape_discard_merge_buffer(drive, 0);
1357                 return idetape_position_tape(drive, 0, mt_count, 0);
1358         case MTFSR:
1359         case MTBSR:
1360         case MTLOCK:
1361                 retval = ide_set_media_lock(drive, disk, 1);
1362                 if (retval)
1363                         return retval;
1364                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
1365                 return 0;
1366         case MTUNLOCK:
1367                 retval = ide_set_media_lock(drive, disk, 0);
1368                 if (retval)
1369                         return retval;
1370                 tape->door_locked = DOOR_UNLOCKED;
1371                 return 0;
1372         default:
1373                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
1374                                 mt_op);
1375                 return -EIO;
1376         }
1377 }
1378
1379 /*
1380  * Our character device ioctls. General mtio.h magnetic io commands are
1381  * supported here, and not in the corresponding block interface. Our own
1382  * ide-tape ioctls are supported on both interfaces.
1383  */
1384 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
1385                                 unsigned int cmd, unsigned long arg)
1386 {
1387         struct ide_tape_obj *tape = file->private_data;
1388         ide_drive_t *drive = tape->drive;
1389         struct mtop mtop;
1390         struct mtget mtget;
1391         struct mtpos mtpos;
1392         int block_offset = 0, position = tape->first_frame;
1393         void __user *argp = (void __user *)arg;
1394
1395         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
1396
1397         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
1398                 ide_tape_flush_merge_buffer(drive);
1399                 idetape_flush_tape_buffers(drive);
1400         }
1401         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
1402                 block_offset = tape->valid /
1403                         (tape->blk_size * tape->user_bs_factor);
1404                 position = ide_tape_read_position(drive);
1405                 if (position < 0)
1406                         return -EIO;
1407         }
1408         switch (cmd) {
1409         case MTIOCTOP:
1410                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
1411                         return -EFAULT;
1412                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
1413         case MTIOCGET:
1414                 memset(&mtget, 0, sizeof(struct mtget));
1415                 mtget.mt_type = MT_ISSCSI2;
1416                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
1417                 mtget.mt_dsreg =
1418                         ((tape->blk_size * tape->user_bs_factor)
1419                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
1420
1421                 if (tape->drv_write_prot)
1422                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
1423
1424                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
1425                         return -EFAULT;
1426                 return 0;
1427         case MTIOCPOS:
1428                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
1429                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
1430                         return -EFAULT;
1431                 return 0;
1432         default:
1433                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
1434                         ide_tape_discard_merge_buffer(drive, 1);
1435                 return idetape_blkdev_ioctl(drive, cmd, arg);
1436         }
1437 }
1438
1439 /*
1440  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
1441  * block size with the reported value.
1442  */
1443 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
1444 {
1445         idetape_tape_t *tape = drive->driver_data;
1446         struct ide_atapi_pc pc;
1447         u8 buf[12];
1448
1449         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
1450         if (ide_queue_pc_tail(drive, tape->disk, &pc, buf, pc.req_xfer)) {
1451                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
1452                 if (tape->blk_size == 0) {
1453                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
1454                                             "block size, assuming 32k\n");
1455                         tape->blk_size = 32768;
1456                 }
1457                 return;
1458         }
1459         tape->blk_size = (buf[4 + 5] << 16) +
1460                                 (buf[4 + 6] << 8)  +
1461                                  buf[4 + 7];
1462         tape->drv_write_prot = (buf[2] & 0x80) >> 7;
1463 }
1464
1465 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
1466 {
1467         unsigned int minor = iminor(inode), i = minor & ~0xc0;
1468         ide_drive_t *drive;
1469         idetape_tape_t *tape;
1470         int retval;
1471
1472         if (i >= MAX_HWIFS * MAX_DRIVES)
1473                 return -ENXIO;
1474
1475         lock_kernel();
1476         tape = ide_tape_get(NULL, true, i);
1477         if (!tape) {
1478                 unlock_kernel();
1479                 return -ENXIO;
1480         }
1481
1482         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1483
1484         /*
1485          * We really want to do nonseekable_open(inode, filp); here, but some
1486          * versions of tar incorrectly call lseek on tapes and bail out if that
1487          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1488          */
1489         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1490
1491         drive = tape->drive;
1492
1493         filp->private_data = tape;
1494
1495         if (test_and_set_bit(ilog2(IDE_AFLAG_BUSY), &drive->atapi_flags)) {
1496                 retval = -EBUSY;
1497                 goto out_put_tape;
1498         }
1499
1500         retval = idetape_wait_ready(drive, 60 * HZ);
1501         if (retval) {
1502                 clear_bit(ilog2(IDE_AFLAG_BUSY), &drive->atapi_flags);
1503                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
1504                 goto out_put_tape;
1505         }
1506
1507         ide_tape_read_position(drive);
1508         if (!test_bit(ilog2(IDE_AFLAG_ADDRESS_VALID), &drive->atapi_flags))
1509                 (void)idetape_rewind_tape(drive);
1510
1511         /* Read block size and write protect status from drive. */
1512         ide_tape_get_bsize_from_bdesc(drive);
1513
1514         /* Set write protect flag if device is opened as read-only. */
1515         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
1516                 tape->write_prot = 1;
1517         else
1518                 tape->write_prot = tape->drv_write_prot;
1519
1520         /* Make sure drive isn't write protected if user wants to write. */
1521         if (tape->write_prot) {
1522                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
1523                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
1524                         clear_bit(ilog2(IDE_AFLAG_BUSY), &drive->atapi_flags);
1525                         retval = -EROFS;
1526                         goto out_put_tape;
1527                 }
1528         }
1529
1530         /* Lock the tape drive door so user can't eject. */
1531         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
1532                 if (!ide_set_media_lock(drive, tape->disk, 1)) {
1533                         if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
1534                                 tape->door_locked = DOOR_LOCKED;
1535                 }
1536         }
1537         unlock_kernel();
1538         return 0;
1539
1540 out_put_tape:
1541         ide_tape_put(tape);
1542         unlock_kernel();
1543         return retval;
1544 }
1545
1546 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
1547 {
1548         idetape_tape_t *tape = drive->driver_data;
1549
1550         ide_tape_flush_merge_buffer(drive);
1551         tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL);
1552         if (tape->buf != NULL) {
1553                 idetape_pad_zeros(drive, tape->blk_size *
1554                                 (tape->user_bs_factor - 1));
1555                 kfree(tape->buf);
1556                 tape->buf = NULL;
1557         }
1558         idetape_write_filemark(drive);
1559         idetape_flush_tape_buffers(drive);
1560         idetape_flush_tape_buffers(drive);
1561 }
1562
1563 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
1564 {
1565         struct ide_tape_obj *tape = filp->private_data;
1566         ide_drive_t *drive = tape->drive;
1567         unsigned int minor = iminor(inode);
1568
1569         lock_kernel();
1570         tape = drive->driver_data;
1571
1572         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
1573
1574         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1575                 idetape_write_release(drive, minor);
1576         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
1577                 if (minor < 128)
1578                         ide_tape_discard_merge_buffer(drive, 1);
1579         }
1580
1581         if (minor < 128 && test_bit(ilog2(IDE_AFLAG_MEDIUM_PRESENT),
1582                                     &drive->atapi_flags))
1583                 (void) idetape_rewind_tape(drive);
1584
1585         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
1586                 if (tape->door_locked == DOOR_LOCKED) {
1587                         if (!ide_set_media_lock(drive, tape->disk, 0))
1588                                 tape->door_locked = DOOR_UNLOCKED;
1589                 }
1590         }
1591         clear_bit(ilog2(IDE_AFLAG_BUSY), &drive->atapi_flags);
1592         ide_tape_put(tape);
1593         unlock_kernel();
1594         return 0;
1595 }
1596
1597 static void idetape_get_inquiry_results(ide_drive_t *drive)
1598 {
1599         idetape_tape_t *tape = drive->driver_data;
1600         struct ide_atapi_pc pc;
1601         u8 pc_buf[256];
1602         char fw_rev[4], vendor_id[8], product_id[16];
1603
1604         idetape_create_inquiry_cmd(&pc);
1605         if (ide_queue_pc_tail(drive, tape->disk, &pc, pc_buf, pc.req_xfer)) {
1606                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
1607                                 tape->name);
1608                 return;
1609         }
1610         memcpy(vendor_id, &pc_buf[8], 8);
1611         memcpy(product_id, &pc_buf[16], 16);
1612         memcpy(fw_rev, &pc_buf[32], 4);
1613
1614         ide_fixstring(vendor_id, 8, 0);
1615         ide_fixstring(product_id, 16, 0);
1616         ide_fixstring(fw_rev, 4, 0);
1617
1618         printk(KERN_INFO "ide-tape: %s <-> %s: %.8s %.16s rev %.4s\n",
1619                         drive->name, tape->name, vendor_id, product_id, fw_rev);
1620 }
1621
1622 /*
1623  * Ask the tape about its various parameters. In particular, we will adjust our
1624  * data transfer buffer size to the recommended value as returned by the tape.
1625  */
1626 static void idetape_get_mode_sense_results(ide_drive_t *drive)
1627 {
1628         idetape_tape_t *tape = drive->driver_data;
1629         struct ide_atapi_pc pc;
1630         u8 buf[24], *caps;
1631         u8 speed, max_speed;
1632
1633         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
1634         if (ide_queue_pc_tail(drive, tape->disk, &pc, buf, pc.req_xfer)) {
1635                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
1636                                 " some default values\n");
1637                 tape->blk_size = 512;
1638                 put_unaligned(52,   (u16 *)&tape->caps[12]);
1639                 put_unaligned(540,  (u16 *)&tape->caps[14]);
1640                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
1641                 return;
1642         }
1643         caps = buf + 4 + buf[3];
1644
1645         /* convert to host order and save for later use */
1646         speed = be16_to_cpup((__be16 *)&caps[14]);
1647         max_speed = be16_to_cpup((__be16 *)&caps[8]);
1648
1649         *(u16 *)&caps[8] = max_speed;
1650         *(u16 *)&caps[12] = be16_to_cpup((__be16 *)&caps[12]);
1651         *(u16 *)&caps[14] = speed;
1652         *(u16 *)&caps[16] = be16_to_cpup((__be16 *)&caps[16]);
1653
1654         if (!speed) {
1655                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
1656                                 "(assuming 650KB/sec)\n", drive->name);
1657                 *(u16 *)&caps[14] = 650;
1658         }
1659         if (!max_speed) {
1660                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
1661                                 "(assuming 650KB/sec)\n", drive->name);
1662                 *(u16 *)&caps[8] = 650;
1663         }
1664
1665         memcpy(&tape->caps, caps, 20);
1666
1667         /* device lacks locking support according to capabilities page */
1668         if ((caps[6] & 1) == 0)
1669                 drive->dev_flags &= ~IDE_DFLAG_DOORLOCKING;
1670
1671         if (caps[7] & 0x02)
1672                 tape->blk_size = 512;
1673         else if (caps[7] & 0x04)
1674                 tape->blk_size = 1024;
1675 }
1676
1677 #ifdef CONFIG_IDE_PROC_FS
1678 #define ide_tape_devset_get(name, field) \
1679 static int get_##name(ide_drive_t *drive) \
1680 { \
1681         idetape_tape_t *tape = drive->driver_data; \
1682         return tape->field; \
1683 }
1684
1685 #define ide_tape_devset_set(name, field) \
1686 static int set_##name(ide_drive_t *drive, int arg) \
1687 { \
1688         idetape_tape_t *tape = drive->driver_data; \
1689         tape->field = arg; \
1690         return 0; \
1691 }
1692
1693 #define ide_tape_devset_rw_field(_name, _field) \
1694 ide_tape_devset_get(_name, _field) \
1695 ide_tape_devset_set(_name, _field) \
1696 IDE_DEVSET(_name, DS_SYNC, get_##_name, set_##_name)
1697
1698 #define ide_tape_devset_r_field(_name, _field) \
1699 ide_tape_devset_get(_name, _field) \
1700 IDE_DEVSET(_name, 0, get_##_name, NULL)
1701
1702 static int mulf_tdsc(ide_drive_t *drive)        { return 1000; }
1703 static int divf_tdsc(ide_drive_t *drive)        { return   HZ; }
1704 static int divf_buffer(ide_drive_t *drive)      { return    2; }
1705 static int divf_buffer_size(ide_drive_t *drive) { return 1024; }
1706
1707 ide_devset_rw_flag(dsc_overlap, IDE_DFLAG_DSC_OVERLAP);
1708
1709 ide_tape_devset_rw_field(debug_mask, debug_mask);
1710 ide_tape_devset_rw_field(tdsc, best_dsc_rw_freq);
1711
1712 ide_tape_devset_r_field(avg_speed, avg_speed);
1713 ide_tape_devset_r_field(speed, caps[14]);
1714 ide_tape_devset_r_field(buffer, caps[16]);
1715 ide_tape_devset_r_field(buffer_size, buffer_size);
1716
1717 static const struct ide_proc_devset idetape_settings[] = {
1718         __IDE_PROC_DEVSET(avg_speed,    0, 0xffff, NULL, NULL),
1719         __IDE_PROC_DEVSET(buffer,       0, 0xffff, NULL, divf_buffer),
1720         __IDE_PROC_DEVSET(buffer_size,  0, 0xffff, NULL, divf_buffer_size),
1721         __IDE_PROC_DEVSET(debug_mask,   0, 0xffff, NULL, NULL),
1722         __IDE_PROC_DEVSET(dsc_overlap,  0,      1, NULL, NULL),
1723         __IDE_PROC_DEVSET(speed,        0, 0xffff, NULL, NULL),
1724         __IDE_PROC_DEVSET(tdsc,         IDETAPE_DSC_RW_MIN, IDETAPE_DSC_RW_MAX,
1725                                         mulf_tdsc, divf_tdsc),
1726         { NULL },
1727 };
1728 #endif
1729
1730 /*
1731  * The function below is called to:
1732  *
1733  * 1. Initialize our various state variables.
1734  * 2. Ask the tape for its capabilities.
1735  * 3. Allocate a buffer which will be used for data transfer. The buffer size
1736  * is chosen based on the recommendation which we received in step 2.
1737  *
1738  * Note that at this point ide.c already assigned us an irq, so that we can
1739  * queue requests here and wait for their completion.
1740  */
1741 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
1742 {
1743         unsigned long t;
1744         int speed;
1745         int buffer_size;
1746         u16 *ctl = (u16 *)&tape->caps[12];
1747
1748         drive->pc_callback       = ide_tape_callback;
1749
1750         drive->dev_flags |= IDE_DFLAG_DSC_OVERLAP;
1751
1752         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
1753                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
1754                                  tape->name);
1755                 drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
1756         }
1757
1758         /* Seagate Travan drives do not support DSC overlap. */
1759         if (strstr((char *)&drive->id[ATA_ID_PROD], "Seagate STT3401"))
1760                 drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
1761
1762         tape->minor = minor;
1763         tape->name[0] = 'h';
1764         tape->name[1] = 't';
1765         tape->name[2] = '0' + minor;
1766         tape->chrdev_dir = IDETAPE_DIR_NONE;
1767
1768         idetape_get_inquiry_results(drive);
1769         idetape_get_mode_sense_results(drive);
1770         ide_tape_get_bsize_from_bdesc(drive);
1771         tape->user_bs_factor = 1;
1772         tape->buffer_size = *ctl * tape->blk_size;
1773         while (tape->buffer_size > 0xffff) {
1774                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
1775                 *ctl /= 2;
1776                 tape->buffer_size = *ctl * tape->blk_size;
1777         }
1778         buffer_size = tape->buffer_size;
1779
1780         /* select the "best" DSC read/write polling freq */
1781         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
1782
1783         t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
1784
1785         /*
1786          * Ensure that the number we got makes sense; limit it within
1787          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
1788          */
1789         tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
1790                                          IDETAPE_DSC_RW_MAX);
1791         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
1792                 "%lums tDSC%s\n",
1793                 drive->name, tape->name, *(u16 *)&tape->caps[14],
1794                 (*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
1795                 tape->buffer_size / 1024,
1796                 tape->best_dsc_rw_freq * 1000 / HZ,
1797                 (drive->dev_flags & IDE_DFLAG_USING_DMA) ? ", DMA" : "");
1798
1799         ide_proc_register_driver(drive, tape->driver);
1800 }
1801
1802 static void ide_tape_remove(ide_drive_t *drive)
1803 {
1804         idetape_tape_t *tape = drive->driver_data;
1805
1806         ide_proc_unregister_driver(drive, tape->driver);
1807         device_del(&tape->dev);
1808         ide_unregister_region(tape->disk);
1809
1810         mutex_lock(&idetape_ref_mutex);
1811         put_device(&tape->dev);
1812         mutex_unlock(&idetape_ref_mutex);
1813 }
1814
1815 static void ide_tape_release(struct device *dev)
1816 {
1817         struct ide_tape_obj *tape = to_ide_drv(dev, ide_tape_obj);
1818         ide_drive_t *drive = tape->drive;
1819         struct gendisk *g = tape->disk;
1820
1821         BUG_ON(tape->valid);
1822
1823         drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
1824         drive->driver_data = NULL;
1825         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
1826         device_destroy(idetape_sysfs_class,
1827                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
1828         idetape_devs[tape->minor] = NULL;
1829         g->private_data = NULL;
1830         put_disk(g);
1831         kfree(tape);
1832 }
1833
1834 #ifdef CONFIG_IDE_PROC_FS
1835 static int proc_idetape_read_name
1836         (char *page, char **start, off_t off, int count, int *eof, void *data)
1837 {
1838         ide_drive_t     *drive = (ide_drive_t *) data;
1839         idetape_tape_t  *tape = drive->driver_data;
1840         char            *out = page;
1841         int             len;
1842
1843         len = sprintf(out, "%s\n", tape->name);
1844         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
1845 }
1846
1847 static ide_proc_entry_t idetape_proc[] = {
1848         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
1849         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
1850         { NULL, 0, NULL, NULL }
1851 };
1852
1853 static ide_proc_entry_t *ide_tape_proc_entries(ide_drive_t *drive)
1854 {
1855         return idetape_proc;
1856 }
1857
1858 static const struct ide_proc_devset *ide_tape_proc_devsets(ide_drive_t *drive)
1859 {
1860         return idetape_settings;
1861 }
1862 #endif
1863
1864 static int ide_tape_probe(ide_drive_t *);
1865
1866 static struct ide_driver idetape_driver = {
1867         .gen_driver = {
1868                 .owner          = THIS_MODULE,
1869                 .name           = "ide-tape",
1870                 .bus            = &ide_bus_type,
1871         },
1872         .probe                  = ide_tape_probe,
1873         .remove                 = ide_tape_remove,
1874         .version                = IDETAPE_VERSION,
1875         .do_request             = idetape_do_request,
1876 #ifdef CONFIG_IDE_PROC_FS
1877         .proc_entries           = ide_tape_proc_entries,
1878         .proc_devsets           = ide_tape_proc_devsets,
1879 #endif
1880 };
1881
1882 /* Our character device supporting functions, passed to register_chrdev. */
1883 static const struct file_operations idetape_fops = {
1884         .owner          = THIS_MODULE,
1885         .read           = idetape_chrdev_read,
1886         .write          = idetape_chrdev_write,
1887         .ioctl          = idetape_chrdev_ioctl,
1888         .open           = idetape_chrdev_open,
1889         .release        = idetape_chrdev_release,
1890 };
1891
1892 static int idetape_open(struct block_device *bdev, fmode_t mode)
1893 {
1894         struct ide_tape_obj *tape = ide_tape_get(bdev->bd_disk, false, 0);
1895
1896         if (!tape)
1897                 return -ENXIO;
1898
1899         return 0;
1900 }
1901
1902 static int idetape_release(struct gendisk *disk, fmode_t mode)
1903 {
1904         struct ide_tape_obj *tape = ide_drv_g(disk, ide_tape_obj);
1905
1906         ide_tape_put(tape);
1907         return 0;
1908 }
1909
1910 static int idetape_ioctl(struct block_device *bdev, fmode_t mode,
1911                         unsigned int cmd, unsigned long arg)
1912 {
1913         struct ide_tape_obj *tape = ide_drv_g(bdev->bd_disk, ide_tape_obj);
1914         ide_drive_t *drive = tape->drive;
1915         int err = generic_ide_ioctl(drive, bdev, cmd, arg);
1916         if (err == -EINVAL)
1917                 err = idetape_blkdev_ioctl(drive, cmd, arg);
1918         return err;
1919 }
1920
1921 static struct block_device_operations idetape_block_ops = {
1922         .owner          = THIS_MODULE,
1923         .open           = idetape_open,
1924         .release        = idetape_release,
1925         .locked_ioctl   = idetape_ioctl,
1926 };
1927
1928 static int ide_tape_probe(ide_drive_t *drive)
1929 {
1930         idetape_tape_t *tape;
1931         struct gendisk *g;
1932         int minor;
1933
1934         if (!strstr("ide-tape", drive->driver_req))
1935                 goto failed;
1936
1937         if (drive->media != ide_tape)
1938                 goto failed;
1939
1940         if ((drive->dev_flags & IDE_DFLAG_ID_READ) &&
1941             ide_check_atapi_device(drive, DRV_NAME) == 0) {
1942                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
1943                                 " the driver\n", drive->name);
1944                 goto failed;
1945         }
1946         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
1947         if (tape == NULL) {
1948                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
1949                                 drive->name);
1950                 goto failed;
1951         }
1952
1953         g = alloc_disk(1 << PARTN_BITS);
1954         if (!g)
1955                 goto out_free_tape;
1956
1957         ide_init_disk(g, drive);
1958
1959         tape->dev.parent = &drive->gendev;
1960         tape->dev.release = ide_tape_release;
1961         dev_set_name(&tape->dev, dev_name(&drive->gendev));
1962
1963         if (device_register(&tape->dev))
1964                 goto out_free_disk;
1965
1966         tape->drive = drive;
1967         tape->driver = &idetape_driver;
1968         tape->disk = g;
1969
1970         g->private_data = &tape->driver;
1971
1972         drive->driver_data = tape;
1973
1974         mutex_lock(&idetape_ref_mutex);
1975         for (minor = 0; idetape_devs[minor]; minor++)
1976                 ;
1977         idetape_devs[minor] = tape;
1978         mutex_unlock(&idetape_ref_mutex);
1979
1980         idetape_setup(drive, tape, minor);
1981
1982         device_create(idetape_sysfs_class, &drive->gendev,
1983                       MKDEV(IDETAPE_MAJOR, minor), NULL, "%s", tape->name);
1984         device_create(idetape_sysfs_class, &drive->gendev,
1985                       MKDEV(IDETAPE_MAJOR, minor + 128), NULL,
1986                       "n%s", tape->name);
1987
1988         g->fops = &idetape_block_ops;
1989         ide_register_region(g);
1990
1991         return 0;
1992
1993 out_free_disk:
1994         put_disk(g);
1995 out_free_tape:
1996         kfree(tape);
1997 failed:
1998         return -ENODEV;
1999 }
2000
2001 static void __exit idetape_exit(void)
2002 {
2003         driver_unregister(&idetape_driver.gen_driver);
2004         class_destroy(idetape_sysfs_class);
2005         unregister_chrdev(IDETAPE_MAJOR, "ht");
2006 }
2007
2008 static int __init idetape_init(void)
2009 {
2010         int error = 1;
2011         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
2012         if (IS_ERR(idetape_sysfs_class)) {
2013                 idetape_sysfs_class = NULL;
2014                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
2015                 error = -EBUSY;
2016                 goto out;
2017         }
2018
2019         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
2020                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
2021                                 " interface\n");
2022                 error = -EBUSY;
2023                 goto out_free_class;
2024         }
2025
2026         error = driver_register(&idetape_driver.gen_driver);
2027         if (error)
2028                 goto out_free_driver;
2029
2030         return 0;
2031
2032 out_free_driver:
2033         driver_unregister(&idetape_driver.gen_driver);
2034 out_free_class:
2035         class_destroy(idetape_sysfs_class);
2036 out:
2037         return error;
2038 }
2039
2040 MODULE_ALIAS("ide:*m-tape*");
2041 module_init(idetape_init);
2042 module_exit(idetape_exit);
2043 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
2044 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
2045 MODULE_LICENSE("GPL");