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 IDETAPE_VERSION "1.20"
  19
  20 #include <linux/module.h>
  21 #include <linux/types.h>
  22 #include <linux/string.h>
  23 #include <linux/kernel.h>
  24 #include <linux/delay.h>
  25 #include <linux/timer.h>
  26 #include <linux/mm.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/jiffies.h>
  29 #include <linux/major.h>
  30 #include <linux/errno.h>
  31 #include <linux/genhd.h>
  32 #include <linux/slab.h>
  33 #include <linux/pci.h>
  34 #include <linux/ide.h>
  35 #include <linux/smp_lock.h>
  36 #include <linux/completion.h>
  37 #include <linux/bitops.h>
  38 #include <linux/mutex.h>
  39 #include <scsi/scsi.h>
  40
  41 #include <asm/byteorder.h>
  42 #include <linux/irq.h>
  43 #include <linux/uaccess.h>
  44 #include <linux/io.h>
  45 #include <asm/unaligned.h>
  46 #include <linux/mtio.h>
  47
  48 enum {
  49         /* output errors only */
  50         DBG_ERR =               (1 << 0),
  51         /* output all sense key/asc */
  52         DBG_SENSE =             (1 << 1),
  53         /* info regarding all chrdev-related procedures */
  54         DBG_CHRDEV =            (1 << 2),
  55         /* all remaining procedures */
  56         DBG_PROCS =             (1 << 3),
  57         /* buffer alloc info (pc_stack & rq_stack) */
  58         DBG_PCRQ_STACK =        (1 << 4),
  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
  77 /*
  78  * Pipelined mode parameters.
  79  *
  80  * We try to use the minimum number of stages which is enough to keep the tape
  81  * constantly streaming. To accomplish that, we implement a feedback loop around
  82  * the maximum number of stages:
  83  *
  84  * We start from MIN maximum stages (we will not even use MIN stages if we don't
  85  * need them), increment it by RATE*(MAX-MIN) whenever we sense that the
  86  * pipeline is empty, until we reach the optimum value or until we reach MAX.
  87  *
  88  * Setting the following parameter to 0 is illegal: the pipelined mode cannot be
  89  * disabled (idetape_calculate_speeds() divides by tape->max_stages.)
  90  */
  91 #define IDETAPE_MIN_PIPELINE_STAGES       1
  92 #define IDETAPE_MAX_PIPELINE_STAGES     400
  93 #define IDETAPE_INCREASE_STAGES_RATE     20
  94
  95 /*
  96  * After each failed packet command we issue a request sense command and retry
  97  * the packet command IDETAPE_MAX_PC_RETRIES times.
  98  *
  99  * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
 100  */
 101 #define IDETAPE_MAX_PC_RETRIES          3
 102
 103 /*
 104  * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
 105  * bytes. This is used for several packet commands (Not for READ/WRITE commands)
 106  */
 107 #define IDETAPE_PC_BUFFER_SIZE          256
 108
 109 /*
 110  *      In various places in the driver, we need to allocate storage
 111  *      for packet commands and requests, which will remain valid while
 112  *      we leave the driver to wait for an interrupt or a timeout event.
 113  */
 114 #define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
 115
 116 /*
 117  * Some drives (for example, Seagate STT3401A Travan) require a very long
 118  * timeout, because they don't return an interrupt or clear their busy bit
 119  * until after the command completes (even retension commands).
 120  */
 121 #define IDETAPE_WAIT_CMD                (900*HZ)
 122
 123 /*
 124  * The following parameter is used to select the point in the internal tape fifo
 125  * in which we will start to refill the buffer. Decreasing the following
 126  * parameter will improve the system's latency and interactive response, while
 127  * using a high value might improve system throughput.
 128  */
 129 #define IDETAPE_FIFO_THRESHOLD          2
 130
 131 /*
 132  * DSC polling parameters.
 133  *
 134  * Polling for DSC (a single bit in the status register) is a very important
 135  * function in ide-tape. There are two cases in which we poll for DSC:
 136  *
 137  * 1. Before a read/write packet command, to ensure that we can transfer data
 138  * from/to the tape's data buffers, without causing an actual media access.
 139  * In case the tape is not ready yet, we take out our request from the device
 140  * request queue, so that ide.c could service requests from the other device
 141  * on the same interface in the meantime.
 142  *
 143  * 2. After the successful initialization of a "media access packet command",
 144  * which is a command that can take a long time to complete (the interval can
 145  * range from several seconds to even an hour). Again, we postpone our request
 146  * in the middle to free the bus for the other device. The polling frequency
 147  * here should be lower than the read/write frequency since those media access
 148  * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
 149  * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
 150  * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
 151  *
 152  * We also set a timeout for the timer, in case something goes wrong. The
 153  * timeout should be longer then the maximum execution time of a tape operation.
 154  */
 155
 156 /* DSC timings. */
 157 #define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
 158 #define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
 159 #define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
 160 #define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
 161 #define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
 162 #define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
 163 #define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
 164
 165 /*************************** End of tunable parameters ***********************/
 166
 167 /* Read/Write error simulation */
 168 #define SIMULATE_ERRORS                 0
 169
 170 /* tape directions */
 171 enum {
 172         IDETAPE_DIR_NONE  = (1 << 0),
 173         IDETAPE_DIR_READ  = (1 << 1),
 174         IDETAPE_DIR_WRITE = (1 << 2),
 175 };
 176
 177 struct idetape_bh {
 178         u32 b_size;
 179         atomic_t b_count;
 180         struct idetape_bh *b_reqnext;
 181         char *b_data;
 182 };
 183
 184 /* Tape door status */
 185 #define DOOR_UNLOCKED                   0
 186 #define DOOR_LOCKED                     1
 187 #define DOOR_EXPLICITLY_LOCKED          2
 188
 189 /* Some defines for the SPACE command */
 190 #define IDETAPE_SPACE_OVER_FILEMARK     1
 191 #define IDETAPE_SPACE_TO_EOD            3
 192
 193 /* Some defines for the LOAD UNLOAD command */
 194 #define IDETAPE_LU_LOAD_MASK            1
 195 #define IDETAPE_LU_RETENSION_MASK       2
 196 #define IDETAPE_LU_EOT_MASK             4
 197
 198 /*
 199  * Special requests for our block device strategy routine.
 200  *
 201  * In order to service a character device command, we add special requests to
 202  * the tail of our block device request queue and wait for their completion.
 203  */
 204
 205 enum {
 206         REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
 207         REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
 208         REQ_IDETAPE_READ        = (1 << 2),
 209         REQ_IDETAPE_WRITE       = (1 << 3),
 210 };
 211
 212 /* Error codes returned in rq->errors to the higher part of the driver. */
 213 #define IDETAPE_ERROR_GENERAL           101
 214 #define IDETAPE_ERROR_FILEMARK          102
 215 #define IDETAPE_ERROR_EOD               103
 216
 217 /* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
 218 #define IDETAPE_BLOCK_DESCRIPTOR        0
 219 #define IDETAPE_CAPABILITIES_PAGE       0x2a
 220
 221 /* Tape flag bits values. */
 222 enum {
 223         IDETAPE_FLAG_IGNORE_DSC         = (1 << 0),
 224         /* 0 When the tape position is unknown */
 225         IDETAPE_FLAG_ADDRESS_VALID      = (1 << 1),
 226         /* Device already opened */
 227         IDETAPE_FLAG_BUSY                       = (1 << 2),
 228         /* Error detected in a pipeline stage */
 229         IDETAPE_FLAG_PIPELINE_ERR       = (1 << 3),
 230         /* Attempt to auto-detect the current user block size */
 231         IDETAPE_FLAG_DETECT_BS          = (1 << 4),
 232         /* Currently on a filemark */
 233         IDETAPE_FLAG_FILEMARK           = (1 << 5),
 234         /* DRQ interrupt device */
 235         IDETAPE_FLAG_DRQ_INTERRUPT      = (1 << 6),
 236         /* pipeline active */
 237         IDETAPE_FLAG_PIPELINE_ACTIVE    = (1 << 7),
 238         /* 0 = no tape is loaded, so we don't rewind after ejecting */
 239         IDETAPE_FLAG_MEDIUM_PRESENT     = (1 << 8),
 240 };
 241
 242 /* A pipeline stage. */
 243 typedef struct idetape_stage_s {
 244         struct request rq;                      /* The corresponding request */
 245         struct idetape_bh *bh;                  /* The data buffers */
 246         struct idetape_stage_s *next;           /* Pointer to the next stage */
 247 } idetape_stage_t;
 248
 249 /*
 250  * Most of our global data which we need to save even as we leave the driver due
 251  * to an interrupt or a timer event is stored in the struct defined below.
 252  */
 253 typedef struct ide_tape_obj {
 254         ide_drive_t     *drive;
 255         ide_driver_t    *driver;
 256         struct gendisk  *disk;
 257         struct kref     kref;
 258
 259         /*
 260          *      Since a typical character device operation requires more
 261          *      than one packet command, we provide here enough memory
 262          *      for the maximum of interconnected packet commands.
 263          *      The packet commands are stored in the circular array pc_stack.
 264          *      pc_stack_index points to the last used entry, and warps around
 265          *      to the start when we get to the last array entry.
 266          *
 267          *      pc points to the current processed packet command.
 268          *
 269          *      failed_pc points to the last failed packet command, or contains
 270          *      NULL if we do not need to retry any packet command. This is
 271          *      required since an additional packet command is needed before the
 272          *      retry, to get detailed information on what went wrong.
 273          */
 274         /* Current packet command */
 275         struct ide_atapi_pc *pc;
 276         /* Last failed packet command */
 277         struct ide_atapi_pc *failed_pc;
 278         /* Packet command stack */
 279         struct ide_atapi_pc pc_stack[IDETAPE_PC_STACK];
 280         /* Next free packet command storage space */
 281         int pc_stack_index;
 282         struct request rq_stack[IDETAPE_PC_STACK];
 283         /* We implement a circular array */
 284         int rq_stack_index;
 285
 286         /*
 287          * DSC polling variables.
 288          *
 289          * While polling for DSC we use postponed_rq to postpone the current
 290          * request so that ide.c will be able to service pending requests on the
 291          * other device. Note that at most we will have only one DSC (usually
 292          * data transfer) request in the device request queue. Additional
 293          * requests can be queued in our internal pipeline, but they will be
 294          * visible to ide.c only one at a time.
 295          */
 296         struct request *postponed_rq;
 297         /* The time in which we started polling for DSC */
 298         unsigned long dsc_polling_start;
 299         /* Timer used to poll for dsc */
 300         struct timer_list dsc_timer;
 301         /* Read/Write dsc polling frequency */
 302         unsigned long best_dsc_rw_freq;
 303         unsigned long dsc_poll_freq;
 304         unsigned long dsc_timeout;
 305
 306         /* Read position information */
 307         u8 partition;
 308         /* Current block */
 309         unsigned int first_frame;
 310
 311         /* Last error information */
 312         u8 sense_key, asc, ascq;
 313
 314         /* Character device operation */
 315         unsigned int minor;
 316         /* device name */
 317         char name[4];
 318         /* Current character device data transfer direction */
 319         u8 chrdev_dir;
 320
 321         /* tape block size, usually 512 or 1024 bytes */
 322         unsigned short blk_size;
 323         int user_bs_factor;
 324
 325         /* Copy of the tape's Capabilities and Mechanical Page */
 326         u8 caps[20];
 327
 328         /*
 329          * Active data transfer request parameters.
 330          *
 331          * At most, there is only one ide-tape originated data transfer request
 332          * in the device request queue. This allows ide.c to easily service
 333          * requests from the other device when we postpone our active request.
 334          * In the pipelined operation mode, we use our internal pipeline
 335          * structure to hold more data requests. The data buffer size is chosen
 336          * based on the tape's recommendation.
 337          */
 338         /* ptr to the request which is waiting in the device request queue */
 339         struct request *active_data_rq;
 340         /* Data buffer size chosen based on the tape's recommendation */
 341         int stage_size;
 342         idetape_stage_t *merge_stage;
 343         int merge_stage_size;
 344         struct idetape_bh *bh;
 345         char *b_data;
 346         int b_count;
 347
 348         /*
 349          * Pipeline parameters.
 350          *
 351          * To accomplish non-pipelined mode, we simply set the following
 352          * variables to zero (or NULL, where appropriate).
 353          */
 354         /* Number of currently used stages */
 355         int nr_stages;
 356         /* Number of pending stages */
 357         int nr_pending_stages;
 358         /* We will not allocate more than this number of stages */
 359         int max_stages, min_pipeline, max_pipeline;
 360         /* The first stage which will be removed from the pipeline */
 361         idetape_stage_t *first_stage;
 362         /* The currently active stage */
 363         idetape_stage_t *active_stage;
 364         /* Will be serviced after the currently active request */
 365         idetape_stage_t *next_stage;
 366         /* New requests will be added to the pipeline here */
 367         idetape_stage_t *last_stage;
 368         /* Optional free stage which we can use */
 369         idetape_stage_t *cache_stage;
 370         int pages_per_stage;
 371         /* Wasted space in each stage */
 372         int excess_bh_size;
 373
 374         /* Status/Action flags: long for set_bit */
 375         unsigned long flags;
 376         /* protects the ide-tape queue */
 377         spinlock_t lock;
 378
 379         /* Measures average tape speed */
 380         unsigned long avg_time;
 381         int avg_size;
 382         int avg_speed;
 383
 384         /* the door is currently locked */
 385         int door_locked;
 386         /* the tape hardware is write protected */
 387         char drv_write_prot;
 388         /* the tape is write protected (hardware or opened as read-only) */
 389         char write_prot;
 390
 391         /*
 392          * Limit the number of times a request can be postponed, to avoid an
 393          * infinite postpone deadlock.
 394          */
 395         int postpone_cnt;
 396
 397         /*
 398          * Measures number of frames:
 399          *
 400          * 1. written/read to/from the driver pipeline (pipeline_head).
 401          * 2. written/read to/from the tape buffers (idetape_bh).
 402          * 3. written/read by the tape to/from the media (tape_head).
 403          */
 404         int pipeline_head;
 405         int buffer_head;
 406         int tape_head;
 407         int last_tape_head;
 408
 409         /* Speed control at the tape buffers input/output */
 410         unsigned long insert_time;
 411         int insert_size;
 412         int insert_speed;
 413         int max_insert_speed;
 414         int measure_insert_time;
 415
 416         /* Speed regulation negative feedback loop */
 417         int speed_control;
 418         int pipeline_head_speed;
 419         int controlled_pipeline_head_speed;
 420         int uncontrolled_pipeline_head_speed;
 421         int controlled_last_pipeline_head;
 422         unsigned long uncontrolled_pipeline_head_time;
 423         unsigned long controlled_pipeline_head_time;
 424         int controlled_previous_pipeline_head;
 425         int uncontrolled_previous_pipeline_head;
 426         unsigned long controlled_previous_head_time;
 427         unsigned long uncontrolled_previous_head_time;
 428         int restart_speed_control_req;
 429
 430         u32 debug_mask;
 431 } idetape_tape_t;
 432
 433 static DEFINE_MUTEX(idetape_ref_mutex);
 434
 435 static struct class *idetape_sysfs_class;
 436
 437 #define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
 438
 439 #define ide_tape_g(disk) \
 440         container_of((disk)->private_data, struct ide_tape_obj, driver)
 441
 442 static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
 443 {
 444         struct ide_tape_obj *tape = NULL;
 445
 446         mutex_lock(&idetape_ref_mutex);
 447         tape = ide_tape_g(disk);
 448         if (tape)
 449                 kref_get(&tape->kref);
 450         mutex_unlock(&idetape_ref_mutex);
 451         return tape;
 452 }
 453
 454 static void ide_tape_release(struct kref *);
 455
 456 static void ide_tape_put(struct ide_tape_obj *tape)
 457 {
 458         mutex_lock(&idetape_ref_mutex);
 459         kref_put(&tape->kref, ide_tape_release);
 460         mutex_unlock(&idetape_ref_mutex);
 461 }
 462
 463 /*
 464  * The variables below are used for the character device interface. Additional
 465  * state variables are defined in our ide_drive_t structure.
 466  */
 467 static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
 468
 469 #define ide_tape_f(file) ((file)->private_data)
 470
 471 static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
 472 {
 473         struct ide_tape_obj *tape = NULL;
 474
 475         mutex_lock(&idetape_ref_mutex);
 476         tape = idetape_devs[i];
 477         if (tape)
 478                 kref_get(&tape->kref);
 479         mutex_unlock(&idetape_ref_mutex);
 480         return tape;
 481 }
 482
 483 static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
 484                                   unsigned int bcount)
 485 {
 486         struct idetape_bh *bh = pc->bh;
 487         int count;
 488
 489         while (bcount) {
 490                 if (bh == NULL) {
 491                         printk(KERN_ERR "ide-tape: bh == NULL in "
 492                                 "idetape_input_buffers\n");
 493                         ide_atapi_discard_data(drive, bcount);
 494                         return;
 495                 }
 496                 count = min(
 497                         (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
 498                         bcount);
 499                 HWIF(drive)->atapi_input_bytes(drive, bh->b_data +
 500                                         atomic_read(&bh->b_count), count);
 501                 bcount -= count;
 502                 atomic_add(count, &bh->b_count);
 503                 if (atomic_read(&bh->b_count) == bh->b_size) {
 504                         bh = bh->b_reqnext;
 505                         if (bh)
 506                                 atomic_set(&bh->b_count, 0);
 507                 }
 508         }
 509         pc->bh = bh;
 510 }
 511
 512 static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
 513                                    unsigned int bcount)
 514 {
 515         struct idetape_bh *bh = pc->bh;
 516         int count;
 517
 518         while (bcount) {
 519                 if (bh == NULL) {
 520                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
 521                                         __func__);
 522                         return;
 523                 }
 524                 count = min((unsigned int)pc->b_count, (unsigned int)bcount);
 525                 HWIF(drive)->atapi_output_bytes(drive, pc->b_data, count);
 526                 bcount -= count;
 527                 pc->b_data += count;
 528                 pc->b_count -= count;
 529                 if (!pc->b_count) {
 530                         bh = bh->b_reqnext;
 531                         pc->bh = bh;
 532                         if (bh) {
 533                                 pc->b_data = bh->b_data;
 534                                 pc->b_count = atomic_read(&bh->b_count);
 535                         }
 536                 }
 537         }
 538 }
 539
 540 static void idetape_update_buffers(struct ide_atapi_pc *pc)
 541 {
 542         struct idetape_bh *bh = pc->bh;
 543         int count;
 544         unsigned int bcount = pc->xferred;
 545
 546         if (pc->flags & PC_FLAG_WRITING)
 547                 return;
 548         while (bcount) {
 549                 if (bh == NULL) {
 550                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
 551                                         __func__);
 552                         return;
 553                 }
 554                 count = min((unsigned int)bh->b_size, (unsigned int)bcount);
 555                 atomic_set(&bh->b_count, count);
 556                 if (atomic_read(&bh->b_count) == bh->b_size)
 557                         bh = bh->b_reqnext;
 558                 bcount -= count;
 559         }
 560         pc->bh = bh;
 561 }
 562
 563 /*
 564  *      idetape_next_pc_storage returns a pointer to a place in which we can
 565  *      safely store a packet command, even though we intend to leave the
 566  *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
 567  *      commands is allocated at initialization time.
 568  */
 569 static struct ide_atapi_pc *idetape_next_pc_storage(ide_drive_t *drive)
 570 {
 571         idetape_tape_t *tape = drive->driver_data;
 572
 573         debug_log(DBG_PCRQ_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);
 574
 575         if (tape->pc_stack_index == IDETAPE_PC_STACK)
 576                 tape->pc_stack_index = 0;
 577         return (&tape->pc_stack[tape->pc_stack_index++]);
 578 }
 579
 580 /*
 581  *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
 582  *      Since we queue packet commands in the request queue, we need to
 583  *      allocate a request, along with the allocation of a packet command.
 584  */
 585
 586 /**************************************************************
 587  *                                                            *
 588  *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
 589  *  followed later on by kfree().   -ml                       *
 590  *                                                            *
 591  **************************************************************/
 592
 593 static struct request *idetape_next_rq_storage(ide_drive_t *drive)
 594 {
 595         idetape_tape_t *tape = drive->driver_data;
 596
 597         debug_log(DBG_PCRQ_STACK, "rq_stack_index=%d\n", tape->rq_stack_index);
 598
 599         if (tape->rq_stack_index == IDETAPE_PC_STACK)
 600                 tape->rq_stack_index = 0;
 601         return (&tape->rq_stack[tape->rq_stack_index++]);
 602 }
 603
 604 static void idetape_init_pc(struct ide_atapi_pc *pc)
 605 {
 606         memset(pc->c, 0, 12);
 607         pc->retries = 0;
 608         pc->flags = 0;
 609         pc->req_xfer = 0;
 610         pc->buf = pc->pc_buf;
 611         pc->buf_size = IDETAPE_PC_BUFFER_SIZE;
 612         pc->bh = NULL;
 613         pc->b_data = NULL;
 614 }
 615
 616 /*
 617  * called on each failed packet command retry to analyze the request sense. We
 618  * currently do not utilize this information.
 619  */
 620 static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 621 {
 622         idetape_tape_t *tape = drive->driver_data;
 623         struct ide_atapi_pc *pc = tape->failed_pc;
 624
 625         tape->sense_key = sense[2] & 0xF;
 626         tape->asc       = sense[12];
 627         tape->ascq      = sense[13];
 628
 629         debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
 630                  pc->c[0], tape->sense_key, tape->asc, tape->ascq);
 631
 632         /* Correct pc->xferred by asking the tape.       */
 633         if (pc->flags & PC_FLAG_DMA_ERROR) {
 634                 pc->xferred = pc->req_xfer -
 635                         tape->blk_size *
 636                         be32_to_cpu(get_unaligned((u32 *)&sense[3]));
 637                 idetape_update_buffers(pc);
 638         }
 639
 640         /*
 641          * If error was the result of a zero-length read or write command,
 642          * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
 643          * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
 644          */
 645         if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
 646             /* length == 0 */
 647             && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
 648                 if (tape->sense_key == 5) {
 649                         /* don't report an error, everything's ok */
 650                         pc->error = 0;
 651                         /* don't retry read/write */
 652                         pc->flags |= PC_FLAG_ABORT;
 653                 }
 654         }
 655         if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
 656                 pc->error = IDETAPE_ERROR_FILEMARK;
 657                 pc->flags |= PC_FLAG_ABORT;
 658         }
 659         if (pc->c[0] == WRITE_6) {
 660                 if ((sense[2] & 0x40) || (tape->sense_key == 0xd
 661                      && tape->asc == 0x0 && tape->ascq == 0x2)) {
 662                         pc->error = IDETAPE_ERROR_EOD;
 663                         pc->flags |= PC_FLAG_ABORT;
 664                 }
 665         }
 666         if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
 667                 if (tape->sense_key == 8) {
 668                         pc->error = IDETAPE_ERROR_EOD;
 669                         pc->flags |= PC_FLAG_ABORT;
 670                 }
 671                 if (!(pc->flags & PC_FLAG_ABORT) &&
 672                     pc->xferred)
 673                         pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
 674         }
 675 }
 676
 677 static void idetape_activate_next_stage(ide_drive_t *drive)
 678 {
 679         idetape_tape_t *tape = drive->driver_data;
 680         idetape_stage_t *stage = tape->next_stage;
 681         struct request *rq = &stage->rq;
 682
 683         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 684
 685         if (stage == NULL) {
 686                 printk(KERN_ERR "ide-tape: bug: Trying to activate a non"
 687                                 " existing stage\n");
 688                 return;
 689         }
 690
 691         rq->rq_disk = tape->disk;
 692         rq->buffer = NULL;
 693         rq->special = (void *)stage->bh;
 694         tape->active_data_rq = rq;
 695         tape->active_stage = stage;
 696         tape->next_stage = stage->next;
 697 }
 698
 699 /* Free a stage along with its related buffers completely. */
 700 static void __idetape_kfree_stage(idetape_stage_t *stage)
 701 {
 702         struct idetape_bh *prev_bh, *bh = stage->bh;
 703         int size;
 704
 705         while (bh != NULL) {
 706                 if (bh->b_data != NULL) {
 707                         size = (int) bh->b_size;
 708                         while (size > 0) {
 709                                 free_page((unsigned long) bh->b_data);
 710                                 size -= PAGE_SIZE;
 711                                 bh->b_data += PAGE_SIZE;
 712                         }
 713                 }
 714                 prev_bh = bh;
 715                 bh = bh->b_reqnext;
 716                 kfree(prev_bh);
 717         }
 718         kfree(stage);
 719 }
 720
 721 static void idetape_kfree_stage(idetape_tape_t *tape, idetape_stage_t *stage)
 722 {
 723         __idetape_kfree_stage(stage);
 724 }
 725
 726 /*
 727  * Remove tape->first_stage from the pipeline. The caller should avoid race
 728  * conditions.
 729  */
 730 static void idetape_remove_stage_head(ide_drive_t *drive)
 731 {
 732         idetape_tape_t *tape = drive->driver_data;
 733         idetape_stage_t *stage;
 734
 735         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 736
 737         if (tape->first_stage == NULL) {
 738                 printk(KERN_ERR "ide-tape: bug: tape->first_stage is NULL\n");
 739                 return;
 740         }
 741         if (tape->active_stage == tape->first_stage) {
 742                 printk(KERN_ERR "ide-tape: bug: Trying to free our active "
 743                                 "pipeline stage\n");
 744                 return;
 745         }
 746         stage = tape->first_stage;
 747         tape->first_stage = stage->next;
 748         idetape_kfree_stage(tape, stage);
 749         tape->nr_stages--;
 750         if (tape->first_stage == NULL) {
 751                 tape->last_stage = NULL;
 752                 if (tape->next_stage != NULL)
 753                         printk(KERN_ERR "ide-tape: bug: tape->next_stage !="
 754                                         " NULL\n");
 755                 if (tape->nr_stages)
 756                         printk(KERN_ERR "ide-tape: bug: nr_stages should be 0 "
 757                                         "now\n");
 758         }
 759 }
 760
 761 /*
 762  * This will free all the pipeline stages starting from new_last_stage->next
 763  * to the end of the list, and point tape->last_stage to new_last_stage.
 764  */
 765 static void idetape_abort_pipeline(ide_drive_t *drive,
 766                                    idetape_stage_t *new_last_stage)
 767 {
 768         idetape_tape_t *tape = drive->driver_data;
 769         idetape_stage_t *stage = new_last_stage->next;
 770         idetape_stage_t *nstage;
 771
 772         debug_log(DBG_PROCS, "%s: Enter %s\n", tape->name, __func__);
 773
 774         while (stage) {
 775                 nstage = stage->next;
 776                 idetape_kfree_stage(tape, stage);
 777                 --tape->nr_stages;
 778                 --tape->nr_pending_stages;
 779                 stage = nstage;
 780         }
 781         if (new_last_stage)
 782                 new_last_stage->next = NULL;
 783         tape->last_stage = new_last_stage;
 784         tape->next_stage = NULL;
 785 }
 786
 787 /*
 788  * Finish servicing a request and insert a pending pipeline request into the
 789  * main device queue.
 790  */
 791 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
 792 {
 793         struct request *rq = HWGROUP(drive)->rq;
 794         idetape_tape_t *tape = drive->driver_data;
 795         unsigned long flags;
 796         int error;
 797         int remove_stage = 0;
 798         idetape_stage_t *active_stage;
 799
 800         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 801
 802         switch (uptodate) {
 803         case 0: error = IDETAPE_ERROR_GENERAL; break;
 804         case 1: error = 0; break;
 805         default: error = uptodate;
 806         }
 807         rq->errors = error;
 808         if (error)
 809                 tape->failed_pc = NULL;
 810
 811         if (!blk_special_request(rq)) {
 812                 ide_end_request(drive, uptodate, nr_sects);
 813                 return 0;
 814         }
 815
 816         spin_lock_irqsave(&tape->lock, flags);
 817
 818         /* The request was a pipelined data transfer request */
 819         if (tape->active_data_rq == rq) {
 820                 active_stage = tape->active_stage;
 821                 tape->active_stage = NULL;
 822                 tape->active_data_rq = NULL;
 823                 tape->nr_pending_stages--;
 824                 if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
 825                         remove_stage = 1;
 826                         if (error) {
 827                                 set_bit(IDETAPE_FLAG_PIPELINE_ERR,
 828                                         &tape->flags);
 829                                 if (error == IDETAPE_ERROR_EOD)
 830                                         idetape_abort_pipeline(drive,
 831                                                                 active_stage);
 832                         }
 833                 } else if (rq->cmd[0] & REQ_IDETAPE_READ) {
 834                         if (error == IDETAPE_ERROR_EOD) {
 835                                 set_bit(IDETAPE_FLAG_PIPELINE_ERR,
 836                                         &tape->flags);
 837                                 idetape_abort_pipeline(drive, active_stage);
 838                         }
 839                 }
 840                 if (tape->next_stage != NULL) {
 841                         idetape_activate_next_stage(drive);
 842
 843                         /* Insert the next request into the request queue. */
 844                         (void)ide_do_drive_cmd(drive, tape->active_data_rq,
 845                                                 ide_end);
 846                 } else if (!error) {
 847                         /*
 848                          * This is a part of the feedback loop which tries to
 849                          * find the optimum number of stages. We are starting
 850                          * from a minimum maximum number of stages, and if we
 851                          * sense that the pipeline is empty, we try to increase
 852                          * it, until we reach the user compile time memory
 853                          * limit.
 854                          */
 855                         int i = (tape->max_pipeline - tape->min_pipeline) / 10;
 856
 857                         tape->max_stages += max(i, 1);
 858                         tape->max_stages = max(tape->max_stages,
 859                                                 tape->min_pipeline);
 860                         tape->max_stages = min(tape->max_stages,
 861                                                 tape->max_pipeline);
 862                 }
 863         }
 864         ide_end_drive_cmd(drive, 0, 0);
 865
 866         if (remove_stage)
 867                 idetape_remove_stage_head(drive);
 868         if (tape->active_data_rq == NULL)
 869                 clear_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags);
 870         spin_unlock_irqrestore(&tape->lock, flags);
 871         return 0;
 872 }
 873
 874 static ide_startstop_t idetape_request_sense_callback(ide_drive_t *drive)
 875 {
 876         idetape_tape_t *tape = drive->driver_data;
 877
 878         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 879
 880         if (!tape->pc->error) {
 881                 idetape_analyze_error(drive, tape->pc->buf);
 882                 idetape_end_request(drive, 1, 0);
 883         } else {
 884                 printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - "
 885                                 "Aborting request!\n");
 886                 idetape_end_request(drive, 0, 0);
 887         }
 888         return ide_stopped;
 889 }
 890
 891 static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
 892 {
 893         idetape_init_pc(pc);
 894         pc->c[0] = REQUEST_SENSE;
 895         pc->c[4] = 20;
 896         pc->req_xfer = 20;
 897         pc->idetape_callback = &idetape_request_sense_callback;
 898 }
 899
 900 static void idetape_init_rq(struct request *rq, u8 cmd)
 901 {
 902         memset(rq, 0, sizeof(*rq));
 903         rq->cmd_type = REQ_TYPE_SPECIAL;
 904         rq->cmd[0] = cmd;
 905 }
 906
 907 /*
 908  * Generate a new packet command request in front of the request queue, before
 909  * the current request, so that it will be processed immediately, on the next
 910  * pass through the driver. The function below is called from the request
 911  * handling part of the driver (the "bottom" part). Safe storage for the request
 912  * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
 913  *
 914  * Memory for those requests is pre-allocated at initialization time, and is
 915  * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
 916  * the maximum possible number of inter-dependent packet commands.
 917  *
 918  * The higher level of the driver - The ioctl handler and the character device
 919  * handling functions should queue request to the lower level part and wait for
 920  * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
 921  */
 922 static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
 923                                   struct request *rq)
 924 {
 925         struct ide_tape_obj *tape = drive->driver_data;
 926
 927         idetape_init_rq(rq, REQ_IDETAPE_PC1);
 928         rq->buffer = (char *) pc;
 929         rq->rq_disk = tape->disk;
 930         (void) ide_do_drive_cmd(drive, rq, ide_preempt);
 931 }
 932
 933 /*
 934  *      idetape_retry_pc is called when an error was detected during the
 935  *      last packet command. We queue a request sense packet command in
 936  *      the head of the request list.
 937  */
 938 static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
 939 {
 940         idetape_tape_t *tape = drive->driver_data;
 941         struct ide_atapi_pc *pc;
 942         struct request *rq;
 943
 944         (void)ide_read_error(drive);
 945         pc = idetape_next_pc_storage(drive);
 946         rq = idetape_next_rq_storage(drive);
 947         idetape_create_request_sense_cmd(pc);
 948         set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
 949         idetape_queue_pc_head(drive, pc, rq);
 950         return ide_stopped;
 951 }
 952
 953 /*
 954  * Postpone the current request so that ide.c will be able to service requests
 955  * from another device on the same hwgroup while we are polling for DSC.
 956  */
 957 static void idetape_postpone_request(ide_drive_t *drive)
 958 {
 959         idetape_tape_t *tape = drive->driver_data;
 960
 961         debug_log(DBG_PROCS, "Enter %s\n", __func__);
 962
 963         tape->postponed_rq = HWGROUP(drive)->rq;
 964         ide_stall_queue(drive, tape->dsc_poll_freq);
 965 }
 966
 967 typedef void idetape_io_buf(ide_drive_t *, struct ide_atapi_pc *, unsigned int);
 968
 969 /*
 970  * This is the usual interrupt handler which will be called during a packet
 971  * command. We will transfer some of the data (as requested by the drive) and
 972  * will re-point interrupt handler to us. When data transfer is finished, we
 973  * will act according to the algorithm described before
 974  * idetape_issue_pc.
 975  */
 976 static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
 977 {
 978         ide_hwif_t *hwif = drive->hwif;
 979         idetape_tape_t *tape = drive->driver_data;
 980         struct ide_atapi_pc *pc = tape->pc;
 981         xfer_func_t *xferfunc;
 982         idetape_io_buf *iobuf;
 983         unsigned int temp;
 984 #if SIMULATE_ERRORS
 985         static int error_sim_count;
 986 #endif
 987         u16 bcount;
 988         u8 stat, ireason;
 989
 990         debug_log(DBG_PROCS, "Enter %s - interrupt handler\n", __func__);
 991
 992         /* Clear the interrupt */
 993         stat = ide_read_status(drive);
 994
 995         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
 996                 if (hwif->dma_ops->dma_end(drive) || (stat & ERR_STAT)) {
 997                         /*
 998                          * A DMA error is sometimes expected. For example,
 999                          * if the tape is crossing a filemark during a
1000                          * READ command, it will issue an irq and position
1001                          * itself before the filemark, so that only a partial
1002                          * data transfer will occur (which causes the DMA
1003                          * error). In that case, we will later ask the tape
1004                          * how much bytes of the original request were
1005                          * actually transferred (we can't receive that
1006                          * information from the DMA engine on most chipsets).
1007                          */
1008
1009                         /*
1010                          * On the contrary, a DMA error is never expected;
1011                          * it usually indicates a hardware error or abort.
1012                          * If the tape crosses a filemark during a READ
1013                          * command, it will issue an irq and position itself
1014                          * after the filemark (not before). Only a partial
1015                          * data transfer will occur, but no DMA error.
1016                          * (AS, 19 Apr 2001)
1017                          */
1018                         pc->flags |= PC_FLAG_DMA_ERROR;
1019                 } else {
1020                         pc->xferred = pc->req_xfer;
1021                         idetape_update_buffers(pc);
1022                 }
1023                 debug_log(DBG_PROCS, "DMA finished\n");
1024
1025         }
1026
1027         /* No more interrupts */
1028         if ((stat & DRQ_STAT) == 0) {
1029                 debug_log(DBG_SENSE, "Packet command completed, %d bytes"
1030                                 " transferred\n", pc->xferred);
1031
1032                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
1033                 local_irq_enable();
1034
1035 #if SIMULATE_ERRORS
1036                 if ((pc->c[0] == WRITE_6 || pc->c[0] == READ_6) &&
1037                     (++error_sim_count % 100) == 0) {
1038                         printk(KERN_INFO "ide-tape: %s: simulating error\n",
1039                                 tape->name);
1040                         stat |= ERR_STAT;
1041                 }
1042 #endif
1043                 if ((stat & ERR_STAT) && pc->c[0] == REQUEST_SENSE)
1044                         stat &= ~ERR_STAT;
1045                 if ((stat & ERR_STAT) || (pc->flags & PC_FLAG_DMA_ERROR)) {
1046                         /* Error detected */
1047                         debug_log(DBG_ERR, "%s: I/O error\n", tape->name);
1048
1049                         if (pc->c[0] == REQUEST_SENSE) {
1050                                 printk(KERN_ERR "ide-tape: I/O error in request"
1051                                                 " sense command\n");
1052                                 return ide_do_reset(drive);
1053                         }
1054                         debug_log(DBG_ERR, "[cmd %x]: check condition\n",
1055                                         pc->c[0]);
1056
1057                         /* Retry operation */
1058                         return idetape_retry_pc(drive);
1059                 }
1060                 pc->error = 0;
1061                 if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) &&
1062                     (stat & SEEK_STAT) == 0) {
1063                         /* Media access command */
1064                         tape->dsc_polling_start = jiffies;
1065                         tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
1066                         tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
1067                         /* Allow ide.c to handle other requests */
1068                         idetape_postpone_request(drive);
1069                         return ide_stopped;
1070                 }
1071                 if (tape->failed_pc == pc)
1072                         tape->failed_pc = NULL;
1073                 /* Command finished - Call the callback function */
1074                 return pc->idetape_callback(drive);
1075         }
1076
1077         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
1078                 pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
1079                 printk(KERN_ERR "ide-tape: The tape wants to issue more "
1080                                 "interrupts in DMA mode\n");
1081                 printk(KERN_ERR "ide-tape: DMA disabled, reverting to PIO\n");
1082                 ide_dma_off(drive);
1083                 return ide_do_reset(drive);
1084         }
1085         /* Get the number of bytes to transfer on this interrupt. */
1086         bcount = (hwif->INB(hwif->io_ports[IDE_BCOUNTH_OFFSET]) << 8) |
1087                   hwif->INB(hwif->io_ports[IDE_BCOUNTL_OFFSET]);
1088
1089         ireason = hwif->INB(hwif->io_ports[IDE_IREASON_OFFSET]);
1090
1091         if (ireason & CD) {
1092                 printk(KERN_ERR "ide-tape: CoD != 0 in %s\n", __func__);
1093                 return ide_do_reset(drive);
1094         }
1095         if (((ireason & IO) == IO) == !!(pc->flags & PC_FLAG_WRITING)) {
1096                 /* Hopefully, we will never get here */
1097                 printk(KERN_ERR "ide-tape: We wanted to %s, ",
1098                                 (ireason & IO) ? "Write" : "Read");
1099                 printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
1100                                 (ireason & IO) ? "Read" : "Write");
1101                 return ide_do_reset(drive);
1102         }
1103         if (!(pc->flags & PC_FLAG_WRITING)) {
1104                 /* Reading - Check that we have enough space */
1105                 temp = pc->xferred + bcount;
1106                 if (temp > pc->req_xfer) {
1107                         if (temp > pc->buf_size) {
1108                                 printk(KERN_ERR "ide-tape: The tape wants to "
1109                                         "send us more data than expected "
1110                                         "- discarding data\n");
1111                                 ide_atapi_discard_data(drive, bcount);
1112                                 ide_set_handler(drive, &idetape_pc_intr,
1113                                                 IDETAPE_WAIT_CMD, NULL);
1114                                 return ide_started;
1115                         }
1116                         debug_log(DBG_SENSE, "The tape wants to send us more "
1117                                 "data than expected - allowing transfer\n");
1118                 }
1119                 iobuf = &idetape_input_buffers;
1120                 xferfunc = hwif->atapi_input_bytes;
1121         } else {
1122                 iobuf = &idetape_output_buffers;
1123                 xferfunc = hwif->atapi_output_bytes;
1124         }
1125
1126         if (pc->bh)
1127                 iobuf(drive, pc, bcount);
1128         else
1129                 xferfunc(drive, pc->cur_pos, bcount);
1130
1131         /* Update the current position */
1132         pc->xferred += bcount;
1133         pc->cur_pos += bcount;
1134
1135         debug_log(DBG_SENSE, "[cmd %x] transferred %d bytes on that intr.\n",
1136                         pc->c[0], bcount);
1137
1138         /* And set the interrupt handler again */
1139         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
1140         return ide_started;
1141 }
1142
1143 /*
1144  * Packet Command Interface
1145  *
1146  * The current Packet Command is available in tape->pc, and will not change
1147  * until we finish handling it. Each packet command is associated with a
1148  * callback function that will be called when the command is finished.
1149  *
1150  * The handling will be done in three stages:
1151  *
1152  * 1. idetape_issue_pc will send the packet command to the drive, and will set
1153  * the interrupt handler to idetape_pc_intr.
1154  *
1155  * 2. On each interrupt, idetape_pc_intr will be called. This step will be
1156  * repeated until the device signals us that no more interrupts will be issued.
1157  *
1158  * 3. ATAPI Tape media access commands have immediate status with a delayed
1159  * process. In case of a successful initiation of a media access packet command,
1160  * the DSC bit will be set when the actual execution of the command is finished.
1161  * Since the tape drive will not issue an interrupt, we have to poll for this
1162  * event. In this case, we define the request as "low priority request" by
1163  * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
1164  * exit the driver.
1165  *
1166  * ide.c will then give higher priority to requests which originate from the
1167  * other device, until will change rq_status to RQ_ACTIVE.
1168  *
1169  * 4. When the packet command is finished, it will be checked for errors.
1170  *
1171  * 5. In case an error was found, we queue a request sense packet command in
1172  * front of the request queue and retry the operation up to
1173  * IDETAPE_MAX_PC_RETRIES times.
1174  *
1175  * 6. In case no error was found, or we decided to give up and not to retry
1176  * again, the callback function will be called and then we will handle the next
1177  * request.
1178  */
1179 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
1180 {
1181         ide_hwif_t *hwif = drive->hwif;
1182         idetape_tape_t *tape = drive->driver_data;
1183         struct ide_atapi_pc *pc = tape->pc;
1184         int retries = 100;
1185         ide_startstop_t startstop;
1186         u8 ireason;
1187
1188         if (ide_wait_stat(&startstop, drive, DRQ_STAT, BUSY_STAT, WAIT_READY)) {
1189                 printk(KERN_ERR "ide-tape: Strange, packet command initiated "
1190                                 "yet DRQ isn't asserted\n");
1191                 return startstop;
1192         }
1193         ireason = hwif->INB(hwif->io_ports[IDE_IREASON_OFFSET]);
1194         while (retries-- && ((ireason & CD) == 0 || (ireason & IO))) {
1195                 printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while issuing "
1196                                 "a packet command, retrying\n");
1197                 udelay(100);
1198                 ireason = hwif->INB(hwif->io_ports[IDE_IREASON_OFFSET]);
1199                 if (retries == 0) {
1200                         printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
1201                                         "issuing a packet command, ignoring\n");
1202                         ireason |= CD;
1203                         ireason &= ~IO;
1204                 }
1205         }
1206         if ((ireason & CD) == 0 || (ireason & IO)) {
1207                 printk(KERN_ERR "ide-tape: (IO,CoD) != (0,1) while issuing "
1208                                 "a packet command\n");
1209                 return ide_do_reset(drive);
1210         }
1211         /* Set the interrupt routine */
1212         ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
1213 #ifdef CONFIG_BLK_DEV_IDEDMA
1214         /* Begin DMA, if necessary */
1215         if (pc->flags & PC_FLAG_DMA_IN_PROGRESS)
1216                 hwif->dma_ops->dma_start(drive);
1217 #endif
1218         /* Send the actual packet */
1219         HWIF(drive)->atapi_output_bytes(drive, pc->c, 12);
1220         return ide_started;
1221 }
1222
1223 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
1224                 struct ide_atapi_pc *pc)
1225 {
1226         ide_hwif_t *hwif = drive->hwif;
1227         idetape_tape_t *tape = drive->driver_data;
1228         int dma_ok = 0;
1229         u16 bcount;
1230
1231         if (tape->pc->c[0] == REQUEST_SENSE &&
1232             pc->c[0] == REQUEST_SENSE) {
1233                 printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
1234                         "Two request sense in serial were issued\n");
1235         }
1236
1237         if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
1238                 tape->failed_pc = pc;
1239         /* Set the current packet command */
1240         tape->pc = pc;
1241
1242         if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
1243                 (pc->flags & PC_FLAG_ABORT)) {
1244                 /*
1245                  * We will "abort" retrying a packet command in case legitimate
1246                  * error code was received (crossing a filemark, or end of the
1247                  * media, for example).
1248                  */
1249                 if (!(pc->flags & PC_FLAG_ABORT)) {
1250                         if (!(pc->c[0] == TEST_UNIT_READY &&
1251                               tape->sense_key == 2 && tape->asc == 4 &&
1252                              (tape->ascq == 1 || tape->ascq == 8))) {
1253                                 printk(KERN_ERR "ide-tape: %s: I/O error, "
1254                                                 "pc = %2x, key = %2x, "
1255                                                 "asc = %2x, ascq = %2x\n",
1256                                                 tape->name, pc->c[0],
1257                                                 tape->sense_key, tape->asc,
1258                                                 tape->ascq);
1259                         }
1260                         /* Giving up */
1261                         pc->error = IDETAPE_ERROR_GENERAL;
1262                 }
1263                 tape->failed_pc = NULL;
1264                 return pc->idetape_callback(drive);
1265         }
1266         debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
1267
1268         pc->retries++;
1269         /* We haven't transferred any data yet */
1270         pc->xferred = 0;
1271         pc->cur_pos = pc->buf;
1272         /* Request to transfer the entire buffer at once */
1273         bcount = pc->req_xfer;
1274
1275         if (pc->flags & PC_FLAG_DMA_ERROR) {
1276                 pc->flags &= ~PC_FLAG_DMA_ERROR;
1277                 printk(KERN_WARNING "ide-tape: DMA disabled, "
1278                                 "reverting to PIO\n");
1279                 ide_dma_off(drive);
1280         }
1281         if ((pc->flags & PC_FLAG_DMA_RECOMMENDED) && drive->using_dma)
1282                 dma_ok = !hwif->dma_ops->dma_setup(drive);
1283
1284         ide_pktcmd_tf_load(drive, IDE_TFLAG_NO_SELECT_MASK |
1285                            IDE_TFLAG_OUT_DEVICE, bcount, dma_ok);
1286
1287         if (dma_ok)
1288                 /* Will begin DMA later */
1289                 pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
1290         if (test_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags)) {
1291                 ide_execute_command(drive, WIN_PACKETCMD, &idetape_transfer_pc,
1292                                     IDETAPE_WAIT_CMD, NULL);
1293                 return ide_started;
1294         } else {
1295                 hwif->OUTB(WIN_PACKETCMD, hwif->io_ports[IDE_COMMAND_OFFSET]);
1296                 return idetape_transfer_pc(drive);
1297         }
1298 }
1299
1300 static ide_startstop_t idetape_pc_callback(ide_drive_t *drive)
1301 {
1302         idetape_tape_t *tape = drive->driver_data;
1303
1304         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1305
1306         idetape_end_request(drive, tape->pc->error ? 0 : 1, 0);
1307         return ide_stopped;
1308 }
1309
1310 /* A mode sense command is used to "sense" tape parameters. */
1311 static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
1312 {
1313         idetape_init_pc(pc);
1314         pc->c[0] = MODE_SENSE;
1315         if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
1316                 /* DBD = 1 - Don't return block descriptors */
1317                 pc->c[1] = 8;
1318         pc->c[2] = page_code;
1319         /*
1320          * Changed pc->c[3] to 0 (255 will at best return unused info).
1321          *
1322          * For SCSI this byte is defined as subpage instead of high byte
1323          * of length and some IDE drives seem to interpret it this way
1324          * and return an error when 255 is used.
1325          */
1326         pc->c[3] = 0;
1327         /* We will just discard data in that case */
1328         pc->c[4] = 255;
1329         if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
1330                 pc->req_xfer = 12;
1331         else if (page_code == IDETAPE_CAPABILITIES_PAGE)
1332                 pc->req_xfer = 24;
1333         else
1334                 pc->req_xfer = 50;
1335         pc->idetape_callback = &idetape_pc_callback;
1336 }
1337
1338 static void idetape_calculate_speeds(ide_drive_t *drive)
1339 {
1340         idetape_tape_t *tape = drive->driver_data;
1341
1342         if (time_after(jiffies,
1343                         tape->controlled_pipeline_head_time + 120 * HZ)) {
1344                 tape->controlled_previous_pipeline_head =
1345                         tape->controlled_last_pipeline_head;
1346                 tape->controlled_previous_head_time =
1347                         tape->controlled_pipeline_head_time;
1348                 tape->controlled_last_pipeline_head = tape->pipeline_head;
1349                 tape->controlled_pipeline_head_time = jiffies;
1350         }
1351         if (time_after(jiffies, tape->controlled_pipeline_head_time + 60 * HZ))
1352                 tape->controlled_pipeline_head_speed = (tape->pipeline_head -
1353                                 tape->controlled_last_pipeline_head) * 32 * HZ /
1354                                 (jiffies - tape->controlled_pipeline_head_time);
1355         else if (time_after(jiffies, tape->controlled_previous_head_time))
1356                 tape->controlled_pipeline_head_speed = (tape->pipeline_head -
1357                                 tape->controlled_previous_pipeline_head) * 32 *
1358                         HZ / (jiffies - tape->controlled_previous_head_time);
1359
1360         if (tape->nr_pending_stages < tape->max_stages/*- 1 */) {
1361                 /* -1 for read mode error recovery */
1362                 if (time_after(jiffies, tape->uncontrolled_previous_head_time +
1363                                         10 * HZ)) {
1364                         tape->uncontrolled_pipeline_head_time = jiffies;
1365                         tape->uncontrolled_pipeline_head_speed =
1366                                 (tape->pipeline_head -
1367                                  tape->uncontrolled_previous_pipeline_head) *
1368                                 32 * HZ / (jiffies -
1369                                         tape->uncontrolled_previous_head_time);
1370                 }
1371         } else {
1372                 tape->uncontrolled_previous_head_time = jiffies;
1373                 tape->uncontrolled_previous_pipeline_head = tape->pipeline_head;
1374                 if (time_after(jiffies, tape->uncontrolled_pipeline_head_time +
1375                                         30 * HZ))
1376                         tape->uncontrolled_pipeline_head_time = jiffies;
1377
1378         }
1379         tape->pipeline_head_speed = max(tape->uncontrolled_pipeline_head_speed,
1380                                         tape->controlled_pipeline_head_speed);
1381
1382         if (tape->speed_control == 1) {
1383                 if (tape->nr_pending_stages >= tape->max_stages / 2)
1384                         tape->max_insert_speed = tape->pipeline_head_speed +
1385                                 (1100 - tape->pipeline_head_speed) * 2 *
1386                                 (tape->nr_pending_stages - tape->max_stages / 2)
1387                                 / tape->max_stages;
1388                 else
1389                         tape->max_insert_speed = 500 +
1390                                 (tape->pipeline_head_speed - 500) * 2 *
1391                                 tape->nr_pending_stages / tape->max_stages;
1392
1393                 if (tape->nr_pending_stages >= tape->max_stages * 99 / 100)
1394                         tape->max_insert_speed = 5000;
1395         } else
1396                 tape->max_insert_speed = tape->speed_control;
1397
1398         tape->max_insert_speed = max(tape->max_insert_speed, 500);
1399 }
1400
1401 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
1402 {
1403         idetape_tape_t *tape = drive->driver_data;
1404         struct ide_atapi_pc *pc = tape->pc;
1405         u8 stat;
1406
1407         stat = ide_read_status(drive);
1408
1409         if (stat & SEEK_STAT) {
1410                 if (stat & ERR_STAT) {
1411                         /* Error detected */
1412                         if (pc->c[0] != TEST_UNIT_READY)
1413                                 printk(KERN_ERR "ide-tape: %s: I/O error, ",
1414                                                 tape->name);
1415                         /* Retry operation */
1416                         return idetape_retry_pc(drive);
1417                 }
1418                 pc->error = 0;
1419                 if (tape->failed_pc == pc)
1420                         tape->failed_pc = NULL;
1421         } else {
1422                 pc->error = IDETAPE_ERROR_GENERAL;
1423                 tape->failed_pc = NULL;
1424         }
1425         return pc->idetape_callback(drive);
1426 }
1427
1428 static ide_startstop_t idetape_rw_callback(ide_drive_t *drive)
1429 {
1430         idetape_tape_t *tape = drive->driver_data;
1431         struct request *rq = HWGROUP(drive)->rq;
1432         int blocks = tape->pc->xferred / tape->blk_size;
1433
1434         tape->avg_size += blocks * tape->blk_size;
1435         tape->insert_size += blocks * tape->blk_size;
1436         if (tape->insert_size > 1024 * 1024)
1437                 tape->measure_insert_time = 1;
1438         if (tape->measure_insert_time) {
1439                 tape->measure_insert_time = 0;
1440                 tape->insert_time = jiffies;
1441                 tape->insert_size = 0;
1442         }
1443         if (time_after(jiffies, tape->insert_time))
1444                 tape->insert_speed = tape->insert_size / 1024 * HZ /
1445                                         (jiffies - tape->insert_time);
1446         if (time_after_eq(jiffies, tape->avg_time + HZ)) {
1447                 tape->avg_speed = tape->avg_size * HZ /
1448                                 (jiffies - tape->avg_time) / 1024;
1449                 tape->avg_size = 0;
1450                 tape->avg_time = jiffies;
1451         }
1452         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1453
1454         tape->first_frame += blocks;
1455         rq->current_nr_sectors -= blocks;
1456
1457         if (!tape->pc->error)
1458                 idetape_end_request(drive, 1, 0);
1459         else
1460                 idetape_end_request(drive, tape->pc->error, 0);
1461         return ide_stopped;
1462 }
1463
1464 static void idetape_create_read_cmd(idetape_tape_t *tape,
1465                 struct ide_atapi_pc *pc,
1466                 unsigned int length, struct idetape_bh *bh)
1467 {
1468         idetape_init_pc(pc);
1469         pc->c[0] = READ_6;
1470         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1471         pc->c[1] = 1;
1472         pc->idetape_callback = &idetape_rw_callback;
1473         pc->bh = bh;
1474         atomic_set(&bh->b_count, 0);
1475         pc->buf = NULL;
1476         pc->buf_size = length * tape->blk_size;
1477         pc->req_xfer = pc->buf_size;
1478         if (pc->req_xfer == tape->stage_size)
1479                 pc->flags |= PC_FLAG_DMA_RECOMMENDED;
1480 }
1481
1482 static void idetape_create_write_cmd(idetape_tape_t *tape,
1483                 struct ide_atapi_pc *pc,
1484                 unsigned int length, struct idetape_bh *bh)
1485 {
1486         idetape_init_pc(pc);
1487         pc->c[0] = WRITE_6;
1488         put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
1489         pc->c[1] = 1;
1490         pc->idetape_callback = &idetape_rw_callback;
1491         pc->flags |= PC_FLAG_WRITING;
1492         pc->bh = bh;
1493         pc->b_data = bh->b_data;
1494         pc->b_count = atomic_read(&bh->b_count);
1495         pc->buf = NULL;
1496         pc->buf_size = length * tape->blk_size;
1497         pc->req_xfer = pc->buf_size;
1498         if (pc->req_xfer == tape->stage_size)
1499                 pc->flags |= PC_FLAG_DMA_RECOMMENDED;
1500 }
1501
1502 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
1503                                           struct request *rq, sector_t block)
1504 {
1505         idetape_tape_t *tape = drive->driver_data;
1506         struct ide_atapi_pc *pc = NULL;
1507         struct request *postponed_rq = tape->postponed_rq;
1508         u8 stat;
1509
1510         debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
1511                         " current_nr_sectors: %d\n",
1512                         rq->sector, rq->nr_sectors, rq->current_nr_sectors);
1513
1514         if (!blk_special_request(rq)) {
1515                 /* We do not support buffer cache originated requests. */
1516                 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
1517                         "request queue (%d)\n", drive->name, rq->cmd_type);
1518                 ide_end_request(drive, 0, 0);
1519                 return ide_stopped;
1520         }
1521
1522         /* Retry a failed packet command */
1523         if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE)
1524                 return idetape_issue_pc(drive, tape->failed_pc);
1525
1526         if (postponed_rq != NULL)
1527                 if (rq != postponed_rq) {
1528                         printk(KERN_ERR "ide-tape: ide-tape.c bug - "
1529                                         "Two DSC requests were queued\n");
1530                         idetape_end_request(drive, 0, 0);
1531                         return ide_stopped;
1532                 }
1533
1534         tape->postponed_rq = NULL;
1535
1536         /*
1537          * If the tape is still busy, postpone our request and service
1538          * the other device meanwhile.
1539          */
1540         stat = ide_read_status(drive);
1541
1542         if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
1543                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1544
1545         if (drive->post_reset == 1) {
1546                 set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
1547                 drive->post_reset = 0;
1548         }
1549
1550         if (time_after(jiffies, tape->insert_time))
1551                 tape->insert_speed = tape->insert_size / 1024 * HZ /
1552                                         (jiffies - tape->insert_time);
1553         idetape_calculate_speeds(drive);
1554         if (!test_and_clear_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags) &&
1555             (stat & SEEK_STAT) == 0) {
1556                 if (postponed_rq == NULL) {
1557                         tape->dsc_polling_start = jiffies;
1558                         tape->dsc_poll_freq = tape->best_dsc_rw_freq;
1559                         tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
1560                 } else if (time_after(jiffies, tape->dsc_timeout)) {
1561                         printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
1562                                 tape->name);
1563                         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1564                                 idetape_media_access_finished(drive);
1565                                 return ide_stopped;
1566                         } else {
1567                                 return ide_do_reset(drive);
1568                         }
1569                 } else if (time_after(jiffies,
1570                                         tape->dsc_polling_start +
1571                                         IDETAPE_DSC_MA_THRESHOLD))
1572                         tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
1573                 idetape_postpone_request(drive);
1574                 return ide_stopped;
1575         }
1576         if (rq->cmd[0] & REQ_IDETAPE_READ) {
1577                 tape->buffer_head++;
1578                 tape->postpone_cnt = 0;
1579                 pc = idetape_next_pc_storage(drive);
1580                 idetape_create_read_cmd(tape, pc, rq->current_nr_sectors,
1581                                         (struct idetape_bh *)rq->special);
1582                 goto out;
1583         }
1584         if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1585                 tape->buffer_head++;
1586                 tape->postpone_cnt = 0;
1587                 pc = idetape_next_pc_storage(drive);
1588                 idetape_create_write_cmd(tape, pc, rq->current_nr_sectors,
1589                                          (struct idetape_bh *)rq->special);
1590                 goto out;
1591         }
1592         if (rq->cmd[0] & REQ_IDETAPE_PC1) {
1593                 pc = (struct ide_atapi_pc *) rq->buffer;
1594                 rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
1595                 rq->cmd[0] |= REQ_IDETAPE_PC2;
1596                 goto out;
1597         }
1598         if (rq->cmd[0] & REQ_IDETAPE_PC2) {
1599                 idetape_media_access_finished(drive);
1600                 return ide_stopped;
1601         }
1602         BUG();
1603 out:
1604         return idetape_issue_pc(drive, pc);
1605 }
1606
1607 /* Pipeline related functions */
1608
1609 /*
1610  * The function below uses __get_free_page to allocate a pipeline stage, along
1611  * with all the necessary small buffers which together make a buffer of size
1612  * tape->stage_size (or a bit more). We attempt to combine sequential pages as
1613  * much as possible.
1614  *
1615  * It returns a pointer to the new allocated stage, or NULL if we can't (or
1616  * don't want to) allocate a stage.
1617  *
1618  * Pipeline stages are optional and are used to increase performance. If we
1619  * can't allocate them, we'll manage without them.
1620  */
1621 static idetape_stage_t *__idetape_kmalloc_stage(idetape_tape_t *tape, int full,
1622                                                 int clear)
1623 {
1624         idetape_stage_t *stage;
1625         struct idetape_bh *prev_bh, *bh;
1626         int pages = tape->pages_per_stage;
1627         char *b_data = NULL;
1628
1629         stage = kmalloc(sizeof(idetape_stage_t), GFP_KERNEL);
1630         if (!stage)
1631                 return NULL;
1632         stage->next = NULL;
1633
1634         stage->bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1635         bh = stage->bh;
1636         if (bh == NULL)
1637                 goto abort;
1638         bh->b_reqnext = NULL;
1639         bh->b_data = (char *) __get_free_page(GFP_KERNEL);
1640         if (!bh->b_data)
1641                 goto abort;
1642         if (clear)
1643                 memset(bh->b_data, 0, PAGE_SIZE);
1644         bh->b_size = PAGE_SIZE;
1645         atomic_set(&bh->b_count, full ? bh->b_size : 0);
1646
1647         while (--pages) {
1648                 b_data = (char *) __get_free_page(GFP_KERNEL);
1649                 if (!b_data)
1650                         goto abort;
1651                 if (clear)
1652                         memset(b_data, 0, PAGE_SIZE);
1653                 if (bh->b_data == b_data + PAGE_SIZE) {
1654                         bh->b_size += PAGE_SIZE;
1655                         bh->b_data -= PAGE_SIZE;
1656                         if (full)
1657                                 atomic_add(PAGE_SIZE, &bh->b_count);
1658                         continue;
1659                 }
1660                 if (b_data == bh->b_data + bh->b_size) {
1661                         bh->b_size += PAGE_SIZE;
1662                         if (full)
1663                                 atomic_add(PAGE_SIZE, &bh->b_count);
1664                         continue;
1665                 }
1666                 prev_bh = bh;
1667                 bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
1668                 if (!bh) {
1669                         free_page((unsigned long) b_data);
1670                         goto abort;
1671                 }
1672                 bh->b_reqnext = NULL;
1673                 bh->b_data = b_data;
1674                 bh->b_size = PAGE_SIZE;
1675                 atomic_set(&bh->b_count, full ? bh->b_size : 0);
1676                 prev_bh->b_reqnext = bh;
1677         }
1678         bh->b_size -= tape->excess_bh_size;
1679         if (full)
1680                 atomic_sub(tape->excess_bh_size, &bh->b_count);
1681         return stage;
1682 abort:
1683         __idetape_kfree_stage(stage);
1684         return NULL;
1685 }
1686
1687 static idetape_stage_t *idetape_kmalloc_stage(idetape_tape_t *tape)
1688 {
1689         idetape_stage_t *cache_stage = tape->cache_stage;
1690
1691         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1692
1693         if (tape->nr_stages >= tape->max_stages)
1694                 return NULL;
1695         if (cache_stage != NULL) {
1696                 tape->cache_stage = NULL;
1697                 return cache_stage;
1698         }
1699         return __idetape_kmalloc_stage(tape, 0, 0);
1700 }
1701
1702 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
1703                 idetape_stage_t *stage, const char __user *buf, int n)
1704 {
1705         struct idetape_bh *bh = tape->bh;
1706         int count;
1707         int ret = 0;
1708
1709         while (n) {
1710                 if (bh == NULL) {
1711                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1712                                         __func__);
1713                         return 1;
1714                 }
1715                 count = min((unsigned int)
1716                                 (bh->b_size - atomic_read(&bh->b_count)),
1717                                 (unsigned int)n);
1718                 if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
1719                                 count))
1720                         ret = 1;
1721                 n -= count;
1722                 atomic_add(count, &bh->b_count);
1723                 buf += count;
1724                 if (atomic_read(&bh->b_count) == bh->b_size) {
1725                         bh = bh->b_reqnext;
1726                         if (bh)
1727                                 atomic_set(&bh->b_count, 0);
1728                 }
1729         }
1730         tape->bh = bh;
1731         return ret;
1732 }
1733
1734 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
1735                 idetape_stage_t *stage, int n)
1736 {
1737         struct idetape_bh *bh = tape->bh;
1738         int count;
1739         int ret = 0;
1740
1741         while (n) {
1742                 if (bh == NULL) {
1743                         printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
1744                                         __func__);
1745                         return 1;
1746                 }
1747                 count = min(tape->b_count, n);
1748                 if  (copy_to_user(buf, tape->b_data, count))
1749                         ret = 1;
1750                 n -= count;
1751                 tape->b_data += count;
1752                 tape->b_count -= count;
1753                 buf += count;
1754                 if (!tape->b_count) {
1755                         bh = bh->b_reqnext;
1756                         tape->bh = bh;
1757                         if (bh) {
1758                                 tape->b_data = bh->b_data;
1759                                 tape->b_count = atomic_read(&bh->b_count);
1760                         }
1761                 }
1762         }
1763         return ret;
1764 }
1765
1766 static void idetape_init_merge_stage(idetape_tape_t *tape)
1767 {
1768         struct idetape_bh *bh = tape->merge_stage->bh;
1769
1770         tape->bh = bh;
1771         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
1772                 atomic_set(&bh->b_count, 0);
1773         else {
1774                 tape->b_data = bh->b_data;
1775                 tape->b_count = atomic_read(&bh->b_count);
1776         }
1777 }
1778
1779 static void idetape_switch_buffers(idetape_tape_t *tape, idetape_stage_t *stage)
1780 {
1781         struct idetape_bh *tmp;
1782
1783         tmp = stage->bh;
1784         stage->bh = tape->merge_stage->bh;
1785         tape->merge_stage->bh = tmp;
1786         idetape_init_merge_stage(tape);
1787 }
1788
1789 /* Add a new stage at the end of the pipeline. */
1790 static void idetape_add_stage_tail(ide_drive_t *drive, idetape_stage_t *stage)
1791 {
1792         idetape_tape_t *tape = drive->driver_data;
1793         unsigned long flags;
1794
1795         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1796
1797         spin_lock_irqsave(&tape->lock, flags);
1798         stage->next = NULL;
1799         if (tape->last_stage != NULL)
1800                 tape->last_stage->next = stage;
1801         else
1802                 tape->first_stage = stage;
1803                 tape->next_stage  = stage;
1804         tape->last_stage = stage;
1805         if (tape->next_stage == NULL)
1806                 tape->next_stage = tape->last_stage;
1807         tape->nr_stages++;
1808         tape->nr_pending_stages++;
1809         spin_unlock_irqrestore(&tape->lock, flags);
1810 }
1811
1812 /* Install a completion in a pending request and sleep until it is serviced. The
1813  * caller should ensure that the request will not be serviced before we install
1814  * the completion (usually by disabling interrupts).
1815  */
1816 static void idetape_wait_for_request(ide_drive_t *drive, struct request *rq)
1817 {
1818         DECLARE_COMPLETION_ONSTACK(wait);
1819         idetape_tape_t *tape = drive->driver_data;
1820
1821         if (rq == NULL || !blk_special_request(rq)) {
1822                 printk(KERN_ERR "ide-tape: bug: Trying to sleep on non-valid"
1823                                  " request\n");
1824                 return;
1825         }
1826         rq->end_io_data = &wait;
1827         rq->end_io = blk_end_sync_rq;
1828         spin_unlock_irq(&tape->lock);
1829         wait_for_completion(&wait);
1830         /* The stage and its struct request have been deallocated */
1831         spin_lock_irq(&tape->lock);
1832 }
1833
1834 static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
1835 {
1836         idetape_tape_t *tape = drive->driver_data;
1837         u8 *readpos = tape->pc->buf;
1838
1839         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1840
1841         if (!tape->pc->error) {
1842                 debug_log(DBG_SENSE, "BOP - %s\n",
1843                                 (readpos[0] & 0x80) ? "Yes" : "No");
1844                 debug_log(DBG_SENSE, "EOP - %s\n",
1845                                 (readpos[0] & 0x40) ? "Yes" : "No");
1846
1847                 if (readpos[0] & 0x4) {
1848                         printk(KERN_INFO "ide-tape: Block location is unknown"
1849                                          "to the tape\n");
1850                         clear_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
1851                         idetape_end_request(drive, 0, 0);
1852                 } else {
1853                         debug_log(DBG_SENSE, "Block Location - %u\n",
1854                                         be32_to_cpu(*(u32 *)&readpos[4]));
1855
1856                         tape->partition = readpos[1];
1857                         tape->first_frame =
1858                                 be32_to_cpu(*(u32 *)&readpos[4]);
1859                         set_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
1860                         idetape_end_request(drive, 1, 0);
1861                 }
1862         } else {
1863                 idetape_end_request(drive, 0, 0);
1864         }
1865         return ide_stopped;
1866 }
1867
1868 /*
1869  * Write a filemark if write_filemark=1. Flush the device buffers without
1870  * writing a filemark otherwise.
1871  */
1872 static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
1873                 struct ide_atapi_pc *pc, int write_filemark)
1874 {
1875         idetape_init_pc(pc);
1876         pc->c[0] = WRITE_FILEMARKS;
1877         pc->c[4] = write_filemark;
1878         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1879         pc->idetape_callback = &idetape_pc_callback;
1880 }
1881
1882 static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
1883 {
1884         idetape_init_pc(pc);
1885         pc->c[0] = TEST_UNIT_READY;
1886         pc->idetape_callback = &idetape_pc_callback;
1887 }
1888
1889 /*
1890  * We add a special packet command request to the tail of the request queue, and
1891  * wait for it to be serviced. This is not to be called from within the request
1892  * handling part of the driver! We allocate here data on the stack and it is
1893  * valid until the request is finished. This is not the case for the bottom part
1894  * of the driver, where we are always leaving the functions to wait for an
1895  * interrupt or a timer event.
1896  *
1897  * From the bottom part of the driver, we should allocate safe memory using
1898  * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
1899  * to the request list without waiting for it to be serviced! In that case, we
1900  * usually use idetape_queue_pc_head().
1901  */
1902 static int __idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
1903 {
1904         struct ide_tape_obj *tape = drive->driver_data;
1905         struct request rq;
1906
1907         idetape_init_rq(&rq, REQ_IDETAPE_PC1);
1908         rq.buffer = (char *) pc;
1909         rq.rq_disk = tape->disk;
1910         return ide_do_drive_cmd(drive, &rq, ide_wait);
1911 }
1912
1913 static void idetape_create_load_unload_cmd(ide_drive_t *drive,
1914                 struct ide_atapi_pc *pc, int cmd)
1915 {
1916         idetape_init_pc(pc);
1917         pc->c[0] = START_STOP;
1918         pc->c[4] = cmd;
1919         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
1920         pc->idetape_callback = &idetape_pc_callback;
1921 }
1922
1923 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
1924 {
1925         idetape_tape_t *tape = drive->driver_data;
1926         struct ide_atapi_pc pc;
1927         int load_attempted = 0;
1928
1929         /* Wait for the tape to become ready */
1930         set_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
1931         timeout += jiffies;
1932         while (time_before(jiffies, timeout)) {
1933                 idetape_create_test_unit_ready_cmd(&pc);
1934                 if (!__idetape_queue_pc_tail(drive, &pc))
1935                         return 0;
1936                 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
1937                     || (tape->asc == 0x3A)) {
1938                         /* no media */
1939                         if (load_attempted)
1940                                 return -ENOMEDIUM;
1941                         idetape_create_load_unload_cmd(drive, &pc,
1942                                                         IDETAPE_LU_LOAD_MASK);
1943                         __idetape_queue_pc_tail(drive, &pc);
1944                         load_attempted = 1;
1945                 /* not about to be ready */
1946                 } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
1947                              (tape->ascq == 1 || tape->ascq == 8)))
1948                         return -EIO;
1949                 msleep(100);
1950         }
1951         return -EIO;
1952 }
1953
1954 static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
1955 {
1956         return __idetape_queue_pc_tail(drive, pc);
1957 }
1958
1959 static int idetape_flush_tape_buffers(ide_drive_t *drive)
1960 {
1961         struct ide_atapi_pc pc;
1962         int rc;
1963
1964         idetape_create_write_filemark_cmd(drive, &pc, 0);
1965         rc = idetape_queue_pc_tail(drive, &pc);
1966         if (rc)
1967                 return rc;
1968         idetape_wait_ready(drive, 60 * 5 * HZ);
1969         return 0;
1970 }
1971
1972 static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
1973 {
1974         idetape_init_pc(pc);
1975         pc->c[0] = READ_POSITION;
1976         pc->req_xfer = 20;
1977         pc->idetape_callback = &idetape_read_position_callback;
1978 }
1979
1980 static int idetape_read_position(ide_drive_t *drive)
1981 {
1982         idetape_tape_t *tape = drive->driver_data;
1983         struct ide_atapi_pc pc;
1984         int position;
1985
1986         debug_log(DBG_PROCS, "Enter %s\n", __func__);
1987
1988         idetape_create_read_position_cmd(&pc);
1989         if (idetape_queue_pc_tail(drive, &pc))
1990                 return -1;
1991         position = tape->first_frame;
1992         return position;
1993 }
1994
1995 static void idetape_create_locate_cmd(ide_drive_t *drive,
1996                 struct ide_atapi_pc *pc,
1997                 unsigned int block, u8 partition, int skip)
1998 {
1999         idetape_init_pc(pc);
2000         pc->c[0] = POSITION_TO_ELEMENT;
2001         pc->c[1] = 2;
2002         put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
2003         pc->c[8] = partition;
2004         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
2005         pc->idetape_callback = &idetape_pc_callback;
2006 }
2007
2008 static int idetape_create_prevent_cmd(ide_drive_t *drive,
2009                 struct ide_atapi_pc *pc, int prevent)
2010 {
2011         idetape_tape_t *tape = drive->driver_data;
2012
2013         /* device supports locking according to capabilities page */
2014         if (!(tape->caps[6] & 0x01))
2015                 return 0;
2016
2017         idetape_init_pc(pc);
2018         pc->c[0] = ALLOW_MEDIUM_REMOVAL;
2019         pc->c[4] = prevent;
2020         pc->idetape_callback = &idetape_pc_callback;
2021         return 1;
2022 }
2023
2024 static int __idetape_discard_read_pipeline(ide_drive_t *drive)
2025 {
2026         idetape_tape_t *tape = drive->driver_data;
2027         unsigned long flags;
2028         int cnt;
2029
2030         if (tape->chrdev_dir != IDETAPE_DIR_READ)
2031                 return 0;
2032
2033         /* Remove merge stage. */
2034         cnt = tape->merge_stage_size / tape->blk_size;
2035         if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
2036                 ++cnt;          /* Filemarks count as 1 sector */
2037         tape->merge_stage_size = 0;
2038         if (tape->merge_stage != NULL) {
2039                 __idetape_kfree_stage(tape->merge_stage);
2040                 tape->merge_stage = NULL;
2041         }
2042
2043         /* Clear pipeline flags. */
2044         clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
2045         tape->chrdev_dir = IDETAPE_DIR_NONE;
2046
2047         /* Remove pipeline stages. */
2048         if (tape->first_stage == NULL)
2049                 return 0;
2050
2051         spin_lock_irqsave(&tape->lock, flags);
2052         tape->next_stage = NULL;
2053         if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags))
2054                 idetape_wait_for_request(drive, tape->active_data_rq);
2055         spin_unlock_irqrestore(&tape->lock, flags);
2056
2057         while (tape->first_stage != NULL) {
2058                 struct request *rq_ptr = &tape->first_stage->rq;
2059
2060                 cnt += rq_ptr->nr_sectors - rq_ptr->current_nr_sectors;
2061                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
2062                         ++cnt;
2063                 idetape_remove_stage_head(drive);
2064         }
2065         tape->nr_pending_stages = 0;
2066         tape->max_stages = tape->min_pipeline;
2067         return cnt;
2068 }
2069
2070 /*
2071  * Position the tape to the requested block using the LOCATE packet command.
2072  * A READ POSITION command is then issued to check where we are positioned. Like
2073  * all higher level operations, we queue the commands at the tail of the request
2074  * queue and wait for their completion.
2075  */
2076 static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
2077                 u8 partition, int skip)
2078 {
2079         idetape_tape_t *tape = drive->driver_data;
2080         int retval;
2081         struct ide_atapi_pc pc;
2082
2083         if (tape->chrdev_dir == IDETAPE_DIR_READ)
2084                 __idetape_discard_read_pipeline(drive);
2085         idetape_wait_ready(drive, 60 * 5 * HZ);
2086         idetape_create_locate_cmd(drive, &pc, block, partition, skip);
2087         retval = idetape_queue_pc_tail(drive, &pc);
2088         if (retval)
2089                 return (retval);
2090
2091         idetape_create_read_position_cmd(&pc);
2092         return (idetape_queue_pc_tail(drive, &pc));
2093 }
2094
2095 static void idetape_discard_read_pipeline(ide_drive_t *drive,
2096                                           int restore_position)
2097 {
2098         idetape_tape_t *tape = drive->driver_data;
2099         int cnt;
2100         int seek, position;
2101
2102         cnt = __idetape_discard_read_pipeline(drive);
2103         if (restore_position) {
2104                 position = idetape_read_position(drive);
2105                 seek = position > cnt ? position - cnt : 0;
2106                 if (idetape_position_tape(drive, seek, 0, 0)) {
2107                         printk(KERN_INFO "ide-tape: %s: position_tape failed in"
2108                                          " discard_pipeline()\n", tape->name);
2109                         return;
2110                 }
2111         }
2112 }
2113
2114 /*
2115  * Generate a read/write request for the block device interface and wait for it
2116  * to be serviced.
2117  */
2118 static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
2119                                  struct idetape_bh *bh)
2120 {
2121         idetape_tape_t *tape = drive->driver_data;
2122         struct request rq;
2123
2124         debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
2125
2126         if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
2127                 printk(KERN_ERR "ide-tape: bug: the pipeline is active in %s\n",
2128                                 __func__);
2129                 return (0);
2130         }
2131
2132         idetape_init_rq(&rq, cmd);
2133         rq.rq_disk = tape->disk;
2134         rq.special = (void *)bh;
2135         rq.sector = tape->first_frame;
2136         rq.nr_sectors           = blocks;
2137         rq.current_nr_sectors   = blocks;
2138         (void) ide_do_drive_cmd(drive, &rq, ide_wait);
2139
2140         if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
2141                 return 0;
2142
2143         if (tape->merge_stage)
2144                 idetape_init_merge_stage(tape);
2145         if (rq.errors == IDETAPE_ERROR_GENERAL)
2146                 return -EIO;
2147         return (tape->blk_size * (blocks-rq.current_nr_sectors));
2148 }
2149
2150 /* start servicing the pipeline stages, starting from tape->next_stage. */
2151 static void idetape_plug_pipeline(ide_drive_t *drive)
2152 {
2153         idetape_tape_t *tape = drive->driver_data;
2154
2155         if (tape->next_stage == NULL)
2156                 return;
2157         if (!test_and_set_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
2158                 idetape_activate_next_stage(drive);
2159                 (void) ide_do_drive_cmd(drive, tape->active_data_rq, ide_end);
2160         }
2161 }
2162
2163 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
2164 {
2165         idetape_init_pc(pc);
2166         pc->c[0] = INQUIRY;
2167         pc->c[4] = 254;
2168         pc->req_xfer = 254;
2169         pc->idetape_callback = &idetape_pc_callback;
2170 }
2171
2172 static void idetape_create_rewind_cmd(ide_drive_t *drive,
2173                 struct ide_atapi_pc *pc)
2174 {
2175         idetape_init_pc(pc);
2176         pc->c[0] = REZERO_UNIT;
2177         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
2178         pc->idetape_callback = &idetape_pc_callback;
2179 }
2180
2181 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
2182 {
2183         idetape_init_pc(pc);
2184         pc->c[0] = ERASE;
2185         pc->c[1] = 1;
2186         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
2187         pc->idetape_callback = &idetape_pc_callback;
2188 }
2189
2190 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
2191 {
2192         idetape_init_pc(pc);
2193         pc->c[0] = SPACE;
2194         put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
2195         pc->c[1] = cmd;
2196         pc->flags |= PC_FLAG_WAIT_FOR_DSC;
2197         pc->idetape_callback = &idetape_pc_callback;
2198 }
2199
2200 static void idetape_wait_first_stage(ide_drive_t *drive)
2201 {
2202         idetape_tape_t *tape = drive->driver_data;
2203         unsigned long flags;
2204
2205         if (tape->first_stage == NULL)
2206                 return;
2207         spin_lock_irqsave(&tape->lock, flags);
2208         if (tape->active_stage == tape->first_stage)
2209                 idetape_wait_for_request(drive, tape->active_data_rq);
2210         spin_unlock_irqrestore(&tape->lock, flags);
2211 }
2212
2213 /*
2214  * Try to add a character device originated write request to our pipeline. In
2215  * case we don't succeed, we revert to non-pipelined operation mode for this
2216  * request. In order to accomplish that, we
2217  *
2218  * 1. Try to allocate a new pipeline stage.
2219  * 2. If we can't, wait for more and more requests to be serviced and try again
2220  * each time.
2221  * 3. If we still can't allocate a stage, fallback to non-pipelined operation
2222  * mode for this request.
2223  */
2224 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
2225 {
2226         idetape_tape_t *tape = drive->driver_data;
2227         idetape_stage_t *new_stage;
2228         unsigned long flags;
2229         struct request *rq;
2230
2231         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2232
2233         /* Attempt to allocate a new stage. Beware possible race conditions. */
2234         while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
2235                 spin_lock_irqsave(&tape->lock, flags);
2236                 if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
2237                         idetape_wait_for_request(drive, tape->active_data_rq);
2238                         spin_unlock_irqrestore(&tape->lock, flags);
2239                 } else {
2240                         spin_unlock_irqrestore(&tape->lock, flags);
2241                         idetape_plug_pipeline(drive);
2242                         if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE,
2243                                         &tape->flags))
2244                                 continue;
2245                         /*
2246                          * The machine is short on memory. Fallback to non-
2247                          * pipelined operation mode for this request.
2248                          */
2249                         return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
2250                                                 blocks, tape->merge_stage->bh);
2251                 }
2252         }
2253         rq = &new_stage->rq;
2254         idetape_init_rq(rq, REQ_IDETAPE_WRITE);
2255         /* Doesn't actually matter - We always assume sequential access */
2256         rq->sector = tape->first_frame;
2257         rq->current_nr_sectors = blocks;
2258         rq->nr_sectors = blocks;
2259
2260         idetape_switch_buffers(tape, new_stage);
2261         idetape_add_stage_tail(drive, new_stage);
2262         tape->pipeline_head++;
2263         idetape_calculate_speeds(drive);
2264
2265         /*
2266          * Estimate whether the tape has stopped writing by checking if our
2267          * write pipeline is currently empty. If we are not writing anymore,
2268          * wait for the pipeline to be almost completely full (90%) before
2269          * starting to service requests, so that we will be able to keep up with
2270          * the higher speeds of the tape.
2271          */
2272         if (!test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
2273                 if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
2274                         tape->nr_stages >= tape->max_stages -
2275                         tape->uncontrolled_pipeline_head_speed * 3 * 1024 /
2276                         tape->blk_size) {
2277                         tape->measure_insert_time = 1;
2278                         tape->insert_time = jiffies;
2279                         tape->insert_size = 0;
2280                         tape->insert_speed = 0;
2281                         idetape_plug_pipeline(drive);
2282                 }
2283         }
2284         if (test_and_clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags))
2285                 /* Return a deferred error */
2286                 return -EIO;
2287         return blocks;
2288 }
2289
2290 /*
2291  * Wait until all pending pipeline requests are serviced. Typically called on
2292  * device close.
2293  */
2294 static void idetape_wait_for_pipeline(ide_drive_t *drive)
2295 {
2296         idetape_tape_t *tape = drive->driver_data;
2297         unsigned long flags;
2298
2299         while (tape->next_stage || test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE,
2300                                                 &tape->flags)) {
2301                 idetape_plug_pipeline(drive);
2302                 spin_lock_irqsave(&tape->lock, flags);
2303                 if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags))
2304                         idetape_wait_for_request(drive, tape->active_data_rq);
2305                 spin_unlock_irqrestore(&tape->lock, flags);
2306         }
2307 }
2308
2309 static void idetape_empty_write_pipeline(ide_drive_t *drive)
2310 {
2311         idetape_tape_t *tape = drive->driver_data;
2312         int blocks, min;
2313         struct idetape_bh *bh;
2314
2315         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
2316                 printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline,"
2317                                 " but we are not writing.\n");
2318                 return;
2319         }
2320         if (tape->merge_stage_size > tape->stage_size) {
2321                 printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
2322                 tape->merge_stage_size = tape->stage_size;
2323         }
2324         if (tape->merge_stage_size) {
2325                 blocks = tape->merge_stage_size / tape->blk_size;
2326                 if (tape->merge_stage_size % tape->blk_size) {
2327                         unsigned int i;
2328
2329                         blocks++;
2330                         i = tape->blk_size - tape->merge_stage_size %
2331                                 tape->blk_size;
2332                         bh = tape->bh->b_reqnext;
2333                         while (bh) {
2334                                 atomic_set(&bh->b_count, 0);
2335                                 bh = bh->b_reqnext;
2336                         }
2337                         bh = tape->bh;
2338                         while (i) {
2339                                 if (bh == NULL) {
2340                                         printk(KERN_INFO "ide-tape: bug,"
2341                                                          " bh NULL\n");
2342                                         break;
2343                                 }
2344                                 min = min(i, (unsigned int)(bh->b_size -
2345                                                 atomic_read(&bh->b_count)));
2346                                 memset(bh->b_data + atomic_read(&bh->b_count),
2347                                                 0, min);
2348                                 atomic_add(min, &bh->b_count);
2349                                 i -= min;
2350                                 bh = bh->b_reqnext;
2351                         }
2352                 }
2353                 (void) idetape_add_chrdev_write_request(drive, blocks);
2354                 tape->merge_stage_size = 0;
2355         }
2356         idetape_wait_for_pipeline(drive);
2357         if (tape->merge_stage != NULL) {
2358                 __idetape_kfree_stage(tape->merge_stage);
2359                 tape->merge_stage = NULL;
2360         }
2361         clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
2362         tape->chrdev_dir = IDETAPE_DIR_NONE;
2363
2364         /*
2365          * On the next backup, perform the feedback loop again. (I don't want to
2366          * keep sense information between backups, as some systems are
2367          * constantly on, and the system load can be totally different on the
2368          * next backup).
2369          */
2370         tape->max_stages = tape->min_pipeline;
2371         if (tape->first_stage != NULL ||
2372             tape->next_stage != NULL ||
2373             tape->last_stage != NULL ||
2374             tape->nr_stages != 0) {
2375                 printk(KERN_ERR "ide-tape: ide-tape pipeline bug, "
2376                         "first_stage %p, next_stage %p, "
2377                         "last_stage %p, nr_stages %d\n",
2378                         tape->first_stage, tape->next_stage,
2379                         tape->last_stage, tape->nr_stages);
2380         }
2381 }
2382
2383 static void idetape_restart_speed_control(ide_drive_t *drive)
2384 {
2385         idetape_tape_t *tape = drive->driver_data;
2386
2387         tape->restart_speed_control_req = 0;
2388         tape->pipeline_head = 0;
2389         tape->controlled_last_pipeline_head = 0;
2390         tape->controlled_previous_pipeline_head = 0;
2391         tape->uncontrolled_previous_pipeline_head = 0;
2392         tape->controlled_pipeline_head_speed = 5000;
2393         tape->pipeline_head_speed = 5000;
2394         tape->uncontrolled_pipeline_head_speed = 0;
2395         tape->controlled_pipeline_head_time =
2396                 tape->uncontrolled_pipeline_head_time = jiffies;
2397         tape->controlled_previous_head_time =
2398                 tape->uncontrolled_previous_head_time = jiffies;
2399 }
2400
2401 static int idetape_init_read(ide_drive_t *drive, int max_stages)
2402 {
2403         idetape_tape_t *tape = drive->driver_data;
2404         idetape_stage_t *new_stage;
2405         struct request rq;
2406         int bytes_read;
2407         u16 blocks = *(u16 *)&tape->caps[12];
2408
2409         /* Initialize read operation */
2410         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
2411                 if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
2412                         idetape_empty_write_pipeline(drive);
2413                         idetape_flush_tape_buffers(drive);
2414                 }
2415                 if (tape->merge_stage || tape->merge_stage_size) {
2416                         printk(KERN_ERR "ide-tape: merge_stage_size should be"
2417                                          " 0 now\n");
2418                         tape->merge_stage_size = 0;
2419                 }
2420                 tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
2421                 if (!tape->merge_stage)
2422                         return -ENOMEM;
2423                 tape->chrdev_dir = IDETAPE_DIR_READ;
2424
2425                 /*
2426                  * Issue a read 0 command to ensure that DSC handshake is
2427                  * switched from completion mode to buffer available mode.
2428                  * No point in issuing this if DSC overlap isn't supported, some
2429                  * drives (Seagate STT3401A) will return an error.
2430                  */
2431                 if (drive->dsc_overlap) {
2432                         bytes_read = idetape_queue_rw_tail(drive,
2433                                                         REQ_IDETAPE_READ, 0,
2434                                                         tape->merge_stage->bh);
2435                         if (bytes_read < 0) {
2436                                 __idetape_kfree_stage(tape->merge_stage);
2437                                 tape->merge_stage = NULL;
2438                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
2439                                 return bytes_read;
2440                         }
2441                 }
2442         }
2443         if (tape->restart_speed_control_req)
2444                 idetape_restart_speed_control(drive);
2445         idetape_init_rq(&rq, REQ_IDETAPE_READ);
2446         rq.sector = tape->first_frame;
2447         rq.nr_sectors = blocks;
2448         rq.current_nr_sectors = blocks;
2449         if (!test_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags) &&
2450             tape->nr_stages < max_stages) {
2451                 new_stage = idetape_kmalloc_stage(tape);
2452                 while (new_stage != NULL) {
2453                         new_stage->rq = rq;
2454                         idetape_add_stage_tail(drive, new_stage);
2455                         if (tape->nr_stages >= max_stages)
2456                                 break;
2457                         new_stage = idetape_kmalloc_stage(tape);
2458                 }
2459         }
2460         if (!test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
2461                 if (tape->nr_pending_stages >= 3 * max_stages / 4) {
2462                         tape->measure_insert_time = 1;
2463                         tape->insert_time = jiffies;
2464                         tape->insert_size = 0;
2465                         tape->insert_speed = 0;
2466                         idetape_plug_pipeline(drive);
2467                 }
2468         }
2469         return 0;
2470 }
2471
2472 /*
2473  * Called from idetape_chrdev_read() to service a character device read request
2474  * and add read-ahead requests to our pipeline.
2475  */
2476 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
2477 {
2478         idetape_tape_t *tape = drive->driver_data;
2479         unsigned long flags;
2480         struct request *rq_ptr;
2481         int bytes_read;
2482
2483         debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
2484
2485         /* If we are at a filemark, return a read length of 0 */
2486         if (test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
2487                 return 0;
2488
2489         /* Wait for the next block to reach the head of the pipeline. */
2490         idetape_init_read(drive, tape->max_stages);
2491         if (tape->first_stage == NULL) {
2492                 if (test_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags))
2493                         return 0;
2494                 return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
2495                                         tape->merge_stage->bh);
2496         }
2497         idetape_wait_first_stage(drive);
2498         rq_ptr = &tape->first_stage->rq;
2499         bytes_read = tape->blk_size * (rq_ptr->nr_sectors -
2500                                         rq_ptr->current_nr_sectors);
2501         rq_ptr->nr_sectors = 0;
2502         rq_ptr->current_nr_sectors = 0;
2503
2504         if (rq_ptr->errors == IDETAPE_ERROR_EOD)
2505                 return 0;
2506         else {
2507                 idetape_switch_buffers(tape, tape->first_stage);
2508                 if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
2509                         set_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
2510                 spin_lock_irqsave(&tape->lock, flags);
2511                 idetape_remove_stage_head(drive);
2512                 spin_unlock_irqrestore(&tape->lock, flags);
2513                 tape->pipeline_head++;
2514                 idetape_calculate_speeds(drive);
2515         }
2516         if (bytes_read > blocks * tape->blk_size) {
2517                 printk(KERN_ERR "ide-tape: bug: trying to return more bytes"
2518                                 " than requested\n");
2519                 bytes_read = blocks * tape->blk_size;
2520         }
2521         return (bytes_read);
2522 }
2523
2524 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
2525 {
2526         idetape_tape_t *tape = drive->driver_data;
2527         struct idetape_bh *bh;
2528         int blocks;
2529
2530         while (bcount) {
2531                 unsigned int count;
2532
2533                 bh = tape->merge_stage->bh;
2534                 count = min(tape->stage_size, bcount);
2535                 bcount -= count;
2536                 blocks = count / tape->blk_size;
2537                 while (count) {
2538                         atomic_set(&bh->b_count,
2539                                    min(count, (unsigned int)bh->b_size));
2540                         memset(bh->b_data, 0, atomic_read(&bh->b_count));
2541                         count -= atomic_read(&bh->b_count);
2542                         bh = bh->b_reqnext;
2543                 }
2544                 idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
2545                                       tape->merge_stage->bh);
2546         }
2547 }
2548
2549 static int idetape_pipeline_size(ide_drive_t *drive)
2550 {
2551         idetape_tape_t *tape = drive->driver_data;
2552         idetape_stage_t *stage;
2553         struct request *rq;
2554         int size = 0;
2555
2556         idetape_wait_for_pipeline(drive);
2557         stage = tape->first_stage;
2558         while (stage != NULL) {
2559                 rq = &stage->rq;
2560                 size += tape->blk_size * (rq->nr_sectors -
2561                                 rq->current_nr_sectors);
2562                 if (rq->errors == IDETAPE_ERROR_FILEMARK)
2563                         size += tape->blk_size;
2564                 stage = stage->next;
2565         }
2566         size += tape->merge_stage_size;
2567         return size;
2568 }
2569
2570 /*
2571  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
2572  * currently support only one partition.
2573  */
2574 static int idetape_rewind_tape(ide_drive_t *drive)
2575 {
2576         int retval;
2577         struct ide_atapi_pc pc;
2578         idetape_tape_t *tape;
2579         tape = drive->driver_data;
2580
2581         debug_log(DBG_SENSE, "Enter %s\n", __func__);
2582
2583         idetape_create_rewind_cmd(drive, &pc);
2584         retval = idetape_queue_pc_tail(drive, &pc);
2585         if (retval)
2586                 return retval;
2587
2588         idetape_create_read_position_cmd(&pc);
2589         retval = idetape_queue_pc_tail(drive, &pc);
2590         if (retval)
2591                 return retval;
2592         return 0;
2593 }
2594
2595 /* mtio.h compatible commands should be issued to the chrdev interface. */
2596 static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
2597                                 unsigned long arg)
2598 {
2599         idetape_tape_t *tape = drive->driver_data;
2600         void __user *argp = (void __user *)arg;
2601
2602         struct idetape_config {
2603                 int dsc_rw_frequency;
2604                 int dsc_media_access_frequency;
2605                 int nr_stages;
2606         } config;
2607
2608         debug_log(DBG_PROCS, "Enter %s\n", __func__);
2609
2610         switch (cmd) {
2611         case 0x0340:
2612                 if (copy_from_user(&config, argp, sizeof(config)))
2613                         return -EFAULT;
2614                 tape->best_dsc_rw_freq = config.dsc_rw_frequency;
2615                 tape->max_stages = config.nr_stages;
2616                 break;
2617         case 0x0350:
2618                 config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
2619                 config.nr_stages = tape->max_stages;
2620                 if (copy_to_user(argp, &config, sizeof(config)))
2621                         return -EFAULT;
2622                 break;
2623         default:
2624                 return -EIO;
2625         }
2626         return 0;
2627 }
2628
2629 /*
2630  * The function below is now a bit more complicated than just passing the
2631  * command to the tape since we may have crossed some filemarks during our
2632  * pipelined read-ahead mode. As a minor side effect, the pipeline enables us to
2633  * support MTFSFM when the filemark is in our internal pipeline even if the tape
2634  * doesn't support spacing over filemarks in the reverse direction.
2635  */
2636 static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
2637                                         int mt_count)
2638 {
2639         idetape_tape_t *tape = drive->driver_data;
2640         struct ide_atapi_pc pc;
2641         unsigned long flags;
2642         int retval, count = 0;
2643         int sprev = !!(tape->caps[4] & 0x20);
2644
2645         if (mt_count == 0)
2646                 return 0;
2647         if (MTBSF == mt_op || MTBSFM == mt_op) {
2648                 if (!sprev)
2649                         return -EIO;
2650                 mt_count = -mt_count;
2651         }
2652
2653         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2654                 /* its a read-ahead buffer, scan it for crossed filemarks. */
2655                 tape->merge_stage_size = 0;
2656                 if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
2657                         ++count;
2658                 while (tape->first_stage != NULL) {
2659                         if (count == mt_count) {
2660                                 if (mt_op == MTFSFM)
2661                                         set_bit(IDETAPE_FLAG_FILEMARK,
2662                                                 &tape->flags);
2663                                 return 0;
2664                         }
2665                         spin_lock_irqsave(&tape->lock, flags);
2666                         if (tape->first_stage == tape->active_stage) {
2667                                 /*
2668                                  * We have reached the active stage in the read
2669                                  * pipeline. There is no point in allowing the
2670                                  * drive to continue reading any farther, so we
2671                                  * stop the pipeline.
2672                                  *
2673                                  * This section should be moved to a separate
2674                                  * subroutine because similar operations are
2675                                  * done in __idetape_discard_read_pipeline(),
2676                                  * for example.
2677                                  */
2678                                 tape->next_stage = NULL;
2679                                 spin_unlock_irqrestore(&tape->lock, flags);
2680                                 idetape_wait_first_stage(drive);
2681                                 tape->next_stage = tape->first_stage->next;
2682                         } else
2683                                 spin_unlock_irqrestore(&tape->lock, flags);
2684                         if (tape->first_stage->rq.errors ==
2685                                         IDETAPE_ERROR_FILEMARK)
2686                                 ++count;
2687                         idetape_remove_stage_head(drive);
2688                 }
2689                 idetape_discard_read_pipeline(drive, 0);
2690         }
2691
2692         /*
2693          * The filemark was not found in our internal pipeline; now we can issue
2694          * the space command.
2695          */
2696         switch (mt_op) {
2697         case MTFSF:
2698         case MTBSF:
2699                 idetape_create_space_cmd(&pc, mt_count - count,
2700                                          IDETAPE_SPACE_OVER_FILEMARK);
2701                 return idetape_queue_pc_tail(drive, &pc);
2702         case MTFSFM:
2703         case MTBSFM:
2704                 if (!sprev)
2705                         return -EIO;
2706                 retval = idetape_space_over_filemarks(drive, MTFSF,
2707                                                       mt_count - count);
2708                 if (retval)
2709                         return retval;
2710                 count = (MTBSFM == mt_op ? 1 : -1);
2711                 return idetape_space_over_filemarks(drive, MTFSF, count);
2712         default:
2713                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
2714                                 mt_op);
2715                 return -EIO;
2716         }
2717 }
2718
2719 /*
2720  * Our character device read / write functions.
2721  *
2722  * The tape is optimized to maximize throughput when it is transferring an
2723  * integral number of the "continuous transfer limit", which is a parameter of
2724  * the specific tape (26kB on my particular tape, 32kB for Onstream).
2725  *
2726  * As of version 1.3 of the driver, the character device provides an abstract
2727  * continuous view of the media - any mix of block sizes (even 1 byte) on the
2728  * same backup/restore procedure is supported. The driver will internally
2729  * convert the requests to the recommended transfer unit, so that an unmatch
2730  * between the user's block size to the recommended size will only result in a
2731  * (slightly) increased driver overhead, but will no longer hit performance.
2732  * This is not applicable to Onstream.
2733  */
2734 static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
2735                                    size_t count, loff_t *ppos)
2736 {
2737         struct ide_tape_obj *tape = ide_tape_f(file);
2738         ide_drive_t *drive = tape->drive;
2739         ssize_t bytes_read, temp, actually_read = 0, rc;
2740         ssize_t ret = 0;
2741         u16 ctl = *(u16 *)&tape->caps[12];
2742
2743         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
2744
2745         if (tape->chrdev_dir != IDETAPE_DIR_READ) {
2746                 if (test_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags))
2747                         if (count > tape->blk_size &&
2748                             (count % tape->blk_size) == 0)
2749                                 tape->user_bs_factor = count / tape->blk_size;
2750         }
2751         rc = idetape_init_read(drive, tape->max_stages);
2752         if (rc < 0)
2753                 return rc;
2754         if (count == 0)
2755                 return (0);
2756         if (tape->merge_stage_size) {
2757                 actually_read = min((unsigned int)(tape->merge_stage_size),
2758                                     (unsigned int)count);
2759                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
2760                                                actually_read))
2761                         ret = -EFAULT;
2762                 buf += actually_read;
2763                 tape->merge_stage_size -= actually_read;
2764                 count -= actually_read;
2765         }
2766         while (count >= tape->stage_size) {
2767                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
2768                 if (bytes_read <= 0)
2769                         goto finish;
2770                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
2771                                                bytes_read))
2772                         ret = -EFAULT;
2773                 buf += bytes_read;
2774                 count -= bytes_read;
2775                 actually_read += bytes_read;
2776         }
2777         if (count) {
2778                 bytes_read = idetape_add_chrdev_read_request(drive, ctl);
2779                 if (bytes_read <= 0)
2780                         goto finish;
2781                 temp = min((unsigned long)count, (unsigned long)bytes_read);
2782                 if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
2783                                                temp))
2784                         ret = -EFAULT;
2785                 actually_read += temp;
2786                 tape->merge_stage_size = bytes_read-temp;
2787         }
2788 finish:
2789         if (!actually_read && test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags)) {
2790                 debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
2791
2792                 idetape_space_over_filemarks(drive, MTFSF, 1);
2793                 return 0;
2794         }
2795
2796         return ret ? ret : actually_read;
2797 }
2798
2799 static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
2800                                      size_t count, loff_t *ppos)
2801 {
2802         struct ide_tape_obj *tape = ide_tape_f(file);
2803         ide_drive_t *drive = tape->drive;
2804         ssize_t actually_written = 0;
2805         ssize_t ret = 0;
2806         u16 ctl = *(u16 *)&tape->caps[12];
2807
2808         /* The drive is write protected. */
2809         if (tape->write_prot)
2810                 return -EACCES;
2811
2812         debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
2813
2814         /* Initialize write operation */
2815         if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
2816                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
2817                         idetape_discard_read_pipeline(drive, 1);
2818                 if (tape->merge_stage || tape->merge_stage_size) {
2819                         printk(KERN_ERR "ide-tape: merge_stage_size "
2820                                 "should be 0 now\n");
2821                         tape->merge_stage_size = 0;
2822                 }
2823                 tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
2824                 if (!tape->merge_stage)
2825                         return -ENOMEM;
2826                 tape->chrdev_dir = IDETAPE_DIR_WRITE;
2827                 idetape_init_merge_stage(tape);
2828
2829                 /*
2830                  * Issue a write 0 command to ensure that DSC handshake is
2831                  * switched from completion mode to buffer available mode. No
2832                  * point in issuing this if DSC overlap isn't supported, some
2833                  * drives (Seagate STT3401A) will return an error.
2834                  */
2835                 if (drive->dsc_overlap) {
2836                         ssize_t retval = idetape_queue_rw_tail(drive,
2837                                                         REQ_IDETAPE_WRITE, 0,
2838                                                         tape->merge_stage->bh);
2839                         if (retval < 0) {
2840                                 __idetape_kfree_stage(tape->merge_stage);
2841                                 tape->merge_stage = NULL;
2842                                 tape->chrdev_dir = IDETAPE_DIR_NONE;
2843                                 return retval;
2844                         }
2845                 }
2846         }
2847         if (count == 0)
2848                 return (0);
2849         if (tape->restart_speed_control_req)
2850                 idetape_restart_speed_control(drive);
2851         if (tape->merge_stage_size) {
2852                 if (tape->merge_stage_size >= tape->stage_size) {
2853                         printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
2854                         tape->merge_stage_size = 0;
2855                 }
2856                 actually_written = min((unsigned int)
2857                                 (tape->stage_size - tape->merge_stage_size),
2858                                 (unsigned int)count);
2859                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
2860                                                  actually_written))
2861                                 ret = -EFAULT;
2862                 buf += actually_written;
2863                 tape->merge_stage_size += actually_written;
2864                 count -= actually_written;
2865
2866                 if (tape->merge_stage_size == tape->stage_size) {
2867                         ssize_t retval;
2868                         tape->merge_stage_size = 0;
2869                         retval = idetape_add_chrdev_write_request(drive, ctl);
2870                         if (retval <= 0)
2871                                 return (retval);
2872                 }
2873         }
2874         while (count >= tape->stage_size) {
2875                 ssize_t retval;
2876                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
2877                                                  tape->stage_size))
2878                         ret = -EFAULT;
2879                 buf += tape->stage_size;
2880                 count -= tape->stage_size;
2881                 retval = idetape_add_chrdev_write_request(drive, ctl);
2882                 actually_written += tape->stage_size;
2883                 if (retval <= 0)
2884                         return (retval);
2885         }
2886         if (count) {
2887                 actually_written += count;
2888                 if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
2889                                                  count))
2890                         ret = -EFAULT;
2891                 tape->merge_stage_size += count;
2892         }
2893         return ret ? ret : actually_written;
2894 }
2895
2896 static int idetape_write_filemark(ide_drive_t *drive)
2897 {
2898         struct ide_atapi_pc pc;
2899
2900         /* Write a filemark */
2901         idetape_create_write_filemark_cmd(drive, &pc, 1);
2902         if (idetape_queue_pc_tail(drive, &pc)) {
2903                 printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
2904                 return -EIO;
2905         }
2906         return 0;
2907 }
2908
2909 /*
2910  * Called from idetape_chrdev_ioctl when the general mtio MTIOCTOP ioctl is
2911  * requested.
2912  *
2913  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
2914  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
2915  * usually not supported (it is supported in the rare case in which we crossed
2916  * the filemark during our read-ahead pipelined operation mode).
2917  *
2918  * The following commands are currently not supported:
2919  *
2920  * MTFSS, MTBSS, MTWSM, MTSETDENSITY, MTSETDRVBUFFER, MT_ST_BOOLEANS,
2921  * MT_ST_WRITE_THRESHOLD.
2922  */
2923 static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
2924 {
2925         idetape_tape_t *tape = drive->driver_data;
2926         struct ide_atapi_pc pc;
2927         int i, retval;
2928
2929         debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
2930                         mt_op, mt_count);
2931
2932         /* Commands which need our pipelined read-ahead stages. */
2933         switch (mt_op) {
2934         case MTFSF:
2935         case MTFSFM:
2936         case MTBSF:
2937         case MTBSFM:
2938                 if (!mt_count)
2939                         return 0;
2940                 return idetape_space_over_filemarks(drive, mt_op, mt_count);
2941         default:
2942                 break;
2943         }
2944
2945         switch (mt_op) {
2946         case MTWEOF:
2947                 if (tape->write_prot)
2948                         return -EACCES;
2949                 idetape_discard_read_pipeline(drive, 1);
2950                 for (i = 0; i < mt_count; i++) {
2951                         retval = idetape_write_filemark(drive);
2952                         if (retval)
2953                                 return retval;
2954                 }
2955                 return 0;
2956         case MTREW:
2957                 idetape_discard_read_pipeline(drive, 0);
2958                 if (idetape_rewind_tape(drive))
2959                         return -EIO;
2960                 return 0;
2961         case MTLOAD:
2962                 idetape_discard_read_pipeline(drive, 0);
2963                 idetape_create_load_unload_cmd(drive, &pc,
2964                                                IDETAPE_LU_LOAD_MASK);
2965                 return idetape_queue_pc_tail(drive, &pc);
2966         case MTUNLOAD:
2967         case MTOFFL:
2968                 /*
2969                  * If door is locked, attempt to unlock before
2970                  * attempting to eject.
2971                  */
2972                 if (tape->door_locked) {
2973                         if (idetape_create_prevent_cmd(drive, &pc, 0))
2974                                 if (!idetape_queue_pc_tail(drive, &pc))
2975                                         tape->door_locked = DOOR_UNLOCKED;
2976                 }
2977                 idetape_discard_read_pipeline(drive, 0);
2978                 idetape_create_load_unload_cmd(drive, &pc,
2979                                               !IDETAPE_LU_LOAD_MASK);
2980                 retval = idetape_queue_pc_tail(drive, &pc);
2981                 if (!retval)
2982                         clear_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
2983                 return retval;
2984         case MTNOP:
2985                 idetape_discard_read_pipeline(drive, 0);
2986                 return idetape_flush_tape_buffers(drive);
2987         case MTRETEN:
2988                 idetape_discard_read_pipeline(drive, 0);
2989                 idetape_create_load_unload_cmd(drive, &pc,
2990                         IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
2991                 return idetape_queue_pc_tail(drive, &pc);
2992         case MTEOM:
2993                 idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
2994                 return idetape_queue_pc_tail(drive, &pc);
2995         case MTERASE:
2996                 (void)idetape_rewind_tape(drive);
2997                 idetape_create_erase_cmd(&pc);
2998                 return idetape_queue_pc_tail(drive, &pc);
2999         case MTSETBLK:
3000                 if (mt_count) {
3001                         if (mt_count < tape->blk_size ||
3002                             mt_count % tape->blk_size)
3003                                 return -EIO;
3004                         tape->user_bs_factor = mt_count / tape->blk_size;
3005                         clear_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
3006                 } else
3007                         set_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
3008                 return 0;
3009         case MTSEEK:
3010                 idetape_discard_read_pipeline(drive, 0);
3011                 return idetape_position_tape(drive,
3012                         mt_count * tape->user_bs_factor, tape->partition, 0);
3013         case MTSETPART:
3014                 idetape_discard_read_pipeline(drive, 0);
3015                 return idetape_position_tape(drive, 0, mt_count, 0);
3016         case MTFSR:
3017         case MTBSR:
3018         case MTLOCK:
3019                 if (!idetape_create_prevent_cmd(drive, &pc, 1))
3020                         return 0;
3021                 retval = idetape_queue_pc_tail(drive, &pc);
3022                 if (retval)
3023                         return retval;
3024                 tape->door_locked = DOOR_EXPLICITLY_LOCKED;
3025                 return 0;
3026         case MTUNLOCK:
3027                 if (!idetape_create_prevent_cmd(drive, &pc, 0))
3028                         return 0;
3029                 retval = idetape_queue_pc_tail(drive, &pc);
3030                 if (retval)
3031                         return retval;
3032                 tape->door_locked = DOOR_UNLOCKED;
3033                 return 0;
3034         default:
3035                 printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",
3036                                 mt_op);
3037                 return -EIO;
3038         }
3039 }
3040
3041 /*
3042  * Our character device ioctls. General mtio.h magnetic io commands are
3043  * supported here, and not in the corresponding block interface. Our own
3044  * ide-tape ioctls are supported on both interfaces.
3045  */
3046 static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
3047                                 unsigned int cmd, unsigned long arg)
3048 {
3049         struct ide_tape_obj *tape = ide_tape_f(file);
3050         ide_drive_t *drive = tape->drive;
3051         struct mtop mtop;
3052         struct mtget mtget;
3053         struct mtpos mtpos;
3054         int block_offset = 0, position = tape->first_frame;
3055         void __user *argp = (void __user *)arg;
3056
3057         debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);
3058
3059         tape->restart_speed_control_req = 1;
3060         if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
3061                 idetape_empty_write_pipeline(drive);
3062                 idetape_flush_tape_buffers(drive);
3063         }
3064         if (cmd == MTIOCGET || cmd == MTIOCPOS) {
3065                 block_offset = idetape_pipeline_size(drive) /
3066                         (tape->blk_size * tape->user_bs_factor);
3067                 position = idetape_read_position(drive);
3068                 if (position < 0)
3069                         return -EIO;
3070         }
3071         switch (cmd) {
3072         case MTIOCTOP:
3073                 if (copy_from_user(&mtop, argp, sizeof(struct mtop)))
3074                         return -EFAULT;
3075                 return idetape_mtioctop(drive, mtop.mt_op, mtop.mt_count);
3076         case MTIOCGET:
3077                 memset(&mtget, 0, sizeof(struct mtget));
3078                 mtget.mt_type = MT_ISSCSI2;
3079                 mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
3080                 mtget.mt_dsreg =
3081                         ((tape->blk_size * tape->user_bs_factor)
3082                          << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
3083
3084                 if (tape->drv_write_prot)
3085                         mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
3086
3087                 if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
3088                         return -EFAULT;
3089                 return 0;
3090         case MTIOCPOS:
3091                 mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
3092                 if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
3093                         return -EFAULT;
3094                 return 0;
3095         default:
3096                 if (tape->chrdev_dir == IDETAPE_DIR_READ)
3097                         idetape_discard_read_pipeline(drive, 1);
3098                 return idetape_blkdev_ioctl(drive, cmd, arg);
3099         }
3100 }
3101
3102 /*
3103  * Do a mode sense page 0 with block descriptor and if it succeeds set the tape
3104  * block size with the reported value.
3105  */
3106 static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
3107 {
3108         idetape_tape_t *tape = drive->driver_data;
3109         struct ide_atapi_pc pc;
3110
3111         idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
3112         if (idetape_queue_pc_tail(drive, &pc)) {
3113                 printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
3114                 if (tape->blk_size == 0) {
3115                         printk(KERN_WARNING "ide-tape: Cannot deal with zero "
3116                                             "block size, assuming 32k\n");
3117                         tape->blk_size = 32768;
3118                 }
3119                 return;
3120         }
3121         tape->blk_size = (pc.buf[4 + 5] << 16) +
3122                                 (pc.buf[4 + 6] << 8)  +
3123                                  pc.buf[4 + 7];
3124         tape->drv_write_prot = (pc.buf[2] & 0x80) >> 7;
3125 }
3126
3127 static int idetape_chrdev_open(struct inode *inode, struct file *filp)
3128 {
3129         unsigned int minor = iminor(inode), i = minor & ~0xc0;
3130         ide_drive_t *drive;
3131         idetape_tape_t *tape;
3132         struct ide_atapi_pc pc;
3133         int retval;
3134
3135         if (i >= MAX_HWIFS * MAX_DRIVES)
3136                 return -ENXIO;
3137
3138         tape = ide_tape_chrdev_get(i);
3139         if (!tape)
3140                 return -ENXIO;
3141
3142         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
3143
3144         /*
3145          * We really want to do nonseekable_open(inode, filp); here, but some
3146          * versions of tar incorrectly call lseek on tapes and bail out if that
3147          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
3148          */
3149         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
3150
3151         drive = tape->drive;
3152
3153         filp->private_data = tape;
3154
3155         if (test_and_set_bit(IDETAPE_FLAG_BUSY, &tape->flags)) {
3156                 retval = -EBUSY;
3157                 goto out_put_tape;
3158         }
3159
3160         retval = idetape_wait_ready(drive, 60 * HZ);
3161         if (retval) {
3162                 clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
3163                 printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
3164                 goto out_put_tape;
3165         }
3166
3167         idetape_read_position(drive);
3168         if (!test_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags))
3169                 (void)idetape_rewind_tape(drive);
3170
3171         if (tape->chrdev_dir != IDETAPE_DIR_READ)
3172                 clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
3173
3174         /* Read block size and write protect status from drive. */
3175         ide_tape_get_bsize_from_bdesc(drive);
3176
3177         /* Set write protect flag if device is opened as read-only. */
3178         if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
3179                 tape->write_prot = 1;
3180         else
3181                 tape->write_prot = tape->drv_write_prot;
3182
3183         /* Make sure drive isn't write protected if user wants to write. */
3184         if (tape->write_prot) {
3185                 if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
3186                     (filp->f_flags & O_ACCMODE) == O_RDWR) {
3187                         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
3188                         retval = -EROFS;
3189                         goto out_put_tape;
3190                 }
3191         }
3192
3193         /* Lock the tape drive door so user can't eject. */
3194         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
3195                 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
3196                         if (!idetape_queue_pc_tail(drive, &pc)) {
3197                                 if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
3198                                         tape->door_locked = DOOR_LOCKED;
3199                         }
3200                 }
3201         }
3202         idetape_restart_speed_control(drive);
3203         tape->restart_speed_control_req = 0;
3204         return 0;
3205
3206 out_put_tape:
3207         ide_tape_put(tape);
3208         return retval;
3209 }
3210
3211 static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
3212 {
3213         idetape_tape_t *tape = drive->driver_data;
3214
3215         idetape_empty_write_pipeline(drive);
3216         tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);
3217         if (tape->merge_stage != NULL) {
3218                 idetape_pad_zeros(drive, tape->blk_size *
3219                                 (tape->user_bs_factor - 1));
3220                 __idetape_kfree_stage(tape->merge_stage);
3221                 tape->merge_stage = NULL;
3222         }
3223         idetape_write_filemark(drive);
3224         idetape_flush_tape_buffers(drive);
3225         idetape_flush_tape_buffers(drive);
3226 }
3227
3228 static int idetape_chrdev_release(struct inode *inode, struct file *filp)
3229 {
3230         struct ide_tape_obj *tape = ide_tape_f(filp);
3231         ide_drive_t *drive = tape->drive;
3232         struct ide_atapi_pc pc;
3233         unsigned int minor = iminor(inode);
3234
3235         lock_kernel();
3236         tape = drive->driver_data;
3237
3238         debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
3239
3240         if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
3241                 idetape_write_release(drive, minor);
3242         if (tape->chrdev_dir == IDETAPE_DIR_READ) {
3243                 if (minor < 128)
3244                         idetape_discard_read_pipeline(drive, 1);
3245                 else
3246                         idetape_wait_for_pipeline(drive);
3247         }
3248         if (tape->cache_stage != NULL) {
3249                 __idetape_kfree_stage(tape->cache_stage);
3250                 tape->cache_stage = NULL;
3251         }
3252         if (minor < 128 && test_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags))
3253                 (void) idetape_rewind_tape(drive);
3254         if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
3255                 if (tape->door_locked == DOOR_LOCKED) {
3256                         if (idetape_create_prevent_cmd(drive, &pc, 0)) {
3257                                 if (!idetape_queue_pc_tail(drive, &pc))
3258                                         tape->door_locked = DOOR_UNLOCKED;
3259                         }
3260                 }
3261         }
3262         clear_bit(IDETAPE_FLAG_BUSY, &tape->flags);
3263         ide_tape_put(tape);
3264         unlock_kernel();
3265         return 0;
3266 }
3267
3268 /*
3269  * check the contents of the ATAPI IDENTIFY command results. We return:
3270  *
3271  * 1 - If the tape can be supported by us, based on the information we have so
3272  * far.
3273  *
3274  * 0 - If this tape driver is not currently supported by us.
3275  */
3276 static int idetape_identify_device(ide_drive_t *drive)
3277 {
3278         u8 gcw[2], protocol, device_type, removable, packet_size;
3279
3280         if (drive->id_read == 0)
3281                 return 1;
3282
3283         *((unsigned short *) &gcw) = drive->id->config;
3284
3285         protocol        =   (gcw[1] & 0xC0) >> 6;
3286         device_type     =    gcw[1] & 0x1F;
3287         removable       = !!(gcw[0] & 0x80);
3288         packet_size     =    gcw[0] & 0x3;
3289
3290         /* Check that we can support this device */
3291         if (protocol != 2)
3292                 printk(KERN_ERR "ide-tape: Protocol (0x%02x) is not ATAPI\n",
3293                                 protocol);
3294         else if (device_type != 1)
3295                 printk(KERN_ERR "ide-tape: Device type (0x%02x) is not set "
3296                                 "to tape\n", device_type);
3297         else if (!removable)
3298                 printk(KERN_ERR "ide-tape: The removable flag is not set\n");
3299         else if (packet_size != 0) {
3300                 printk(KERN_ERR "ide-tape: Packet size (0x%02x) is not 12"
3301                                 " bytes\n", packet_size);
3302         } else
3303                 return 1;
3304         return 0;
3305 }
3306
3307 static void idetape_get_inquiry_results(ide_drive_t *drive)
3308 {
3309         idetape_tape_t *tape = drive->driver_data;
3310         struct ide_atapi_pc pc;
3311         char fw_rev[6], vendor_id[10], product_id[18];
3312
3313         idetape_create_inquiry_cmd(&pc);
3314         if (idetape_queue_pc_tail(drive, &pc)) {
3315                 printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n",
3316                                 tape->name);
3317                 return;
3318         }
3319         memcpy(vendor_id, &pc.buf[8], 8);
3320         memcpy(product_id, &pc.buf[16], 16);
3321         memcpy(fw_rev, &pc.buf[32], 4);
3322
3323         ide_fixstring(vendor_id, 10, 0);
3324         ide_fixstring(product_id, 18, 0);
3325         ide_fixstring(fw_rev, 6, 0);
3326
3327         printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n",
3328                         drive->name, tape->name, vendor_id, product_id, fw_rev);
3329 }
3330
3331 /*
3332  * Ask the tape about its various parameters. In particular, we will adjust our
3333  * data transfer buffer size to the recommended value as returned by the tape.
3334  */
3335 static void idetape_get_mode_sense_results(ide_drive_t *drive)
3336 {
3337         idetape_tape_t *tape = drive->driver_data;
3338         struct ide_atapi_pc pc;
3339         u8 *caps;
3340         u8 speed, max_speed;
3341
3342         idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
3343         if (idetape_queue_pc_tail(drive, &pc)) {
3344                 printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming"
3345                                 " some default values\n");
3346                 tape->blk_size = 512;
3347                 put_unaligned(52,   (u16 *)&tape->caps[12]);
3348                 put_unaligned(540,  (u16 *)&tape->caps[14]);
3349                 put_unaligned(6*52, (u16 *)&tape->caps[16]);
3350                 return;
3351         }
3352         caps = pc.buf + 4 + pc.buf[3];
3353
3354         /* convert to host order and save for later use */
3355         speed = be16_to_cpu(*(u16 *)&caps[14]);
3356         max_speed = be16_to_cpu(*(u16 *)&caps[8]);
3357
3358         put_unaligned(max_speed, (u16 *)&caps[8]);
3359         put_unaligned(be16_to_cpu(*(u16 *)&caps[12]), (u16 *)&caps[12]);
3360         put_unaligned(speed, (u16 *)&caps[14]);
3361         put_unaligned(be16_to_cpu(*(u16 *)&caps[16]), (u16 *)&caps[16]);
3362
3363         if (!speed) {
3364                 printk(KERN_INFO "ide-tape: %s: invalid tape speed "
3365                                 "(assuming 650KB/sec)\n", drive->name);
3366                 put_unaligned(650, (u16 *)&caps[14]);
3367         }
3368         if (!max_speed) {
3369                 printk(KERN_INFO "ide-tape: %s: invalid max_speed "
3370                                 "(assuming 650KB/sec)\n", drive->name);
3371                 put_unaligned(650, (u16 *)&caps[8]);
3372         }
3373
3374         memcpy(&tape->caps, caps, 20);
3375         if (caps[7] & 0x02)
3376                 tape->blk_size = 512;
3377         else if (caps[7] & 0x04)
3378                 tape->blk_size = 1024;
3379 }
3380
3381 #ifdef CONFIG_IDE_PROC_FS
3382 static void idetape_add_settings(ide_drive_t *drive)
3383 {
3384         idetape_tape_t *tape = drive->driver_data;
3385
3386         ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
3387                         1, 2, (u16 *)&tape->caps[16], NULL);
3388         ide_add_setting(drive, "pipeline_min", SETTING_RW, TYPE_INT, 1, 0xffff,
3389                         tape->stage_size / 1024, 1, &tape->min_pipeline, NULL);
3390         ide_add_setting(drive, "pipeline", SETTING_RW, TYPE_INT, 1, 0xffff,
3391                         tape->stage_size / 1024, 1, &tape->max_stages, NULL);
3392         ide_add_setting(drive, "pipeline_max", SETTING_RW, TYPE_INT, 1, 0xffff,
3393                         tape->stage_size / 1024, 1, &tape->max_pipeline, NULL);
3394         ide_add_setting(drive, "pipeline_used", SETTING_READ, TYPE_INT, 0,
3395                         0xffff, tape->stage_size / 1024, 1, &tape->nr_stages,
3396                         NULL);
3397         ide_add_setting(drive, "pipeline_pending", SETTING_READ, TYPE_INT, 0,
3398                         0xffff, tape->stage_size / 1024, 1,
3399                         &tape->nr_pending_stages, NULL);
3400         ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
3401                         1, 1, (u16 *)&tape->caps[14], NULL);
3402         ide_add_setting(drive, "stage", SETTING_READ, TYPE_INT, 0, 0xffff, 1,
3403                         1024, &tape->stage_size, NULL);
3404         ide_add_setting(drive, "tdsc", SETTING_RW, TYPE_INT, IDETAPE_DSC_RW_MIN,
3405                         IDETAPE_DSC_RW_MAX, 1000, HZ, &tape->best_dsc_rw_freq,
3406                         NULL);
3407         ide_add_setting(drive, "dsc_overlap", SETTING_RW, TYPE_BYTE, 0, 1, 1,
3408                         1, &drive->dsc_overlap, NULL);
3409         ide_add_setting(drive, "pipeline_head_speed_c", SETTING_READ, TYPE_INT,
3410                         0, 0xffff, 1, 1, &tape->controlled_pipeline_head_speed,
3411                         NULL);
3412         ide_add_setting(drive, "pipeline_head_speed_u", SETTING_READ, TYPE_INT,
3413                         0, 0xffff, 1, 1,
3414                         &tape->uncontrolled_pipeline_head_speed, NULL);
3415         ide_add_setting(drive, "avg_speed", SETTING_READ, TYPE_INT, 0, 0xffff,
3416                         1, 1, &tape->avg_speed, NULL);
3417         ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
3418                         1, &tape->debug_mask, NULL);
3419 }
3420 #else
3421 static inline void idetape_add_settings(ide_drive_t *drive) { ; }
3422 #endif
3423
3424 /*
3425  * The function below is called to:
3426  *
3427  * 1. Initialize our various state variables.
3428  * 2. Ask the tape for its capabilities.
3429  * 3. Allocate a buffer which will be used for data transfer. The buffer size
3430  * is chosen based on the recommendation which we received in step 2.
3431  *
3432  * Note that at this point ide.c already assigned us an irq, so that we can
3433  * queue requests here and wait for their completion.
3434  */
3435 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
3436 {
3437         unsigned long t1, tmid, tn, t;
3438         int speed;
3439         int stage_size;
3440         u8 gcw[2];
3441         struct sysinfo si;
3442         u16 *ctl = (u16 *)&tape->caps[12];
3443
3444         spin_lock_init(&tape->lock);
3445         drive->dsc_overlap = 1;
3446         if (drive->hwif->host_flags & IDE_HFLAG_NO_DSC) {
3447                 printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n",
3448                                  tape->name);
3449                 drive->dsc_overlap = 0;
3450         }
3451         /* Seagate Travan drives do not support DSC overlap. */
3452         if (strstr(drive->id->model, "Seagate STT3401"))
3453                 drive->dsc_overlap = 0;
3454         tape->minor = minor;
3455         tape->name[0] = 'h';
3456         tape->name[1] = 't';
3457         tape->name[2] = '0' + minor;
3458         tape->chrdev_dir = IDETAPE_DIR_NONE;
3459         tape->pc = tape->pc_stack;
3460         tape->max_insert_speed = 10000;
3461         tape->speed_control = 1;
3462         *((unsigned short *) &gcw) = drive->id->config;
3463
3464         /* Command packet DRQ type */
3465         if (((gcw[0] & 0x60) >> 5) == 1)
3466                 set_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags);
3467
3468         tape->min_pipeline = 10;
3469         tape->max_pipeline = 10;
3470         tape->max_stages   = 10;
3471
3472         idetape_get_inquiry_results(drive);
3473         idetape_get_mode_sense_results(drive);
3474         ide_tape_get_bsize_from_bdesc(drive);
3475         tape->user_bs_factor = 1;
3476         tape->stage_size = *ctl * tape->blk_size;
3477         while (tape->stage_size > 0xffff) {
3478                 printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
3479                 *ctl /= 2;
3480                 tape->stage_size = *ctl * tape->blk_size;
3481         }
3482         stage_size = tape->stage_size;
3483         tape->pages_per_stage = stage_size / PAGE_SIZE;
3484         if (stage_size % PAGE_SIZE) {
3485                 tape->pages_per_stage++;
3486                 tape->excess_bh_size = PAGE_SIZE - stage_size % PAGE_SIZE;
3487         }
3488
3489         /* Select the "best" DSC read/write polling freq and pipeline size. */
3490         speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
3491
3492         tape->max_stages = speed * 1000 * 10 / tape->stage_size;
3493
3494         /* Limit memory use for pipeline to 10% of physical memory */
3495         si_meminfo(&si);
3496         if (tape->max_stages * tape->stage_size >
3497                         si.totalram * si.mem_unit / 10)
3498                 tape->max_stages =
3499                         si.totalram * si.mem_unit / (10 * tape->stage_size);
3500
3501         tape->max_stages   = min(tape->max_stages, IDETAPE_MAX_PIPELINE_STAGES);
3502         tape->min_pipeline = min(tape->max_stages, IDETAPE_MIN_PIPELINE_STAGES);
3503         tape->max_pipeline =
3504                 min(tape->max_stages * 2, IDETAPE_MAX_PIPELINE_STAGES);
3505         if (tape->max_stages == 0) {
3506                 tape->max_stages   = 1;
3507                 tape->min_pipeline = 1;
3508                 tape->max_pipeline = 1;
3509         }
3510
3511         t1 = (tape->stage_size * HZ) / (speed * 1000);
3512         tmid = (*(u16 *)&tape->caps[16] * 32 * HZ) / (speed * 125);
3513         tn = (IDETAPE_FIFO_THRESHOLD * tape->stage_size * HZ) / (speed * 1000);
3514
3515         if (tape->max_stages)
3516                 t = tn;
3517         else
3518                 t = t1;
3519
3520         /*
3521          * Ensure that the number we got makes sense; limit it within
3522          * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
3523          */
3524         tape->best_dsc_rw_freq = max_t(unsigned long,
3525                                 min_t(unsigned long, t, IDETAPE_DSC_RW_MAX),
3526                                 IDETAPE_DSC_RW_MIN);
3527         printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
3528                 "%dkB pipeline, %lums tDSC%s\n",
3529                 drive->name, tape->name, *(u16 *)&tape->caps[14],
3530                 (*(u16 *)&tape->caps[16] * 512) / tape->stage_size,
3531                 tape->stage_size / 1024,
3532                 tape->max_stages * tape->stage_size / 1024,
3533                 tape->best_dsc_rw_freq * 1000 / HZ,
3534                 drive->using_dma ? ", DMA":"");
3535
3536         idetape_add_settings(drive);
3537 }
3538
3539 static void ide_tape_remove(ide_drive_t *drive)
3540 {
3541         idetape_tape_t *tape = drive->driver_data;
3542
3543         ide_proc_unregister_driver(drive, tape->driver);
3544
3545         ide_unregister_region(tape->disk);
3546
3547         ide_tape_put(tape);
3548 }
3549
3550 static void ide_tape_release(struct kref *kref)
3551 {
3552         struct ide_tape_obj *tape = to_ide_tape(kref);
3553         ide_drive_t *drive = tape->drive;
3554         struct gendisk *g = tape->disk;
3555
3556         BUG_ON(tape->first_stage != NULL || tape->merge_stage_size);
3557
3558         drive->dsc_overlap = 0;
3559         drive->driver_data = NULL;
3560         device_destroy(idetape_sysfs_class, MKDEV(IDETAPE_MAJOR, tape->minor));
3561         device_destroy(idetape_sysfs_class,
3562                         MKDEV(IDETAPE_MAJOR, tape->minor + 128));
3563         idetape_devs[tape->minor] = NULL;
3564         g->private_data = NULL;
3565         put_disk(g);
3566         kfree(tape);
3567 }
3568
3569 #ifdef CONFIG_IDE_PROC_FS
3570 static int proc_idetape_read_name
3571         (char *page, char **start, off_t off, int count, int *eof, void *data)
3572 {
3573         ide_drive_t     *drive = (ide_drive_t *) data;
3574         idetape_tape_t  *tape = drive->driver_data;
3575         char            *out = page;
3576         int             len;
3577
3578         len = sprintf(out, "%s\n", tape->name);
3579         PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
3580 }
3581
3582 static ide_proc_entry_t idetape_proc[] = {
3583         { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
3584         { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
3585         { NULL, 0, NULL, NULL }
3586 };
3587 #endif
3588
3589 static int ide_tape_probe(ide_drive_t *);
3590
3591 static ide_driver_t idetape_driver = {
3592         .gen_driver = {
3593                 .owner          = THIS_MODULE,
3594                 .name           = "ide-tape",
3595                 .bus            = &ide_bus_type,
3596         },
3597         .probe                  = ide_tape_probe,
3598         .remove                 = ide_tape_remove,
3599         .version                = IDETAPE_VERSION,
3600         .media                  = ide_tape,
3601         .supports_dsc_overlap   = 1,
3602         .do_request             = idetape_do_request,
3603         .end_request            = idetape_end_request,
3604         .error                  = __ide_error,
3605         .abort                  = __ide_abort,
3606 #ifdef CONFIG_IDE_PROC_FS
3607         .proc                   = idetape_proc,
3608 #endif
3609 };
3610
3611 /* Our character device supporting functions, passed to register_chrdev. */
3612 static const struct file_operations idetape_fops = {
3613         .owner          = THIS_MODULE,
3614         .read           = idetape_chrdev_read,
3615         .write          = idetape_chrdev_write,
3616         .ioctl          = idetape_chrdev_ioctl,
3617         .open           = idetape_chrdev_open,
3618         .release        = idetape_chrdev_release,
3619 };
3620
3621 static int idetape_open(struct inode *inode, struct file *filp)
3622 {
3623         struct gendisk *disk = inode->i_bdev->bd_disk;
3624         struct ide_tape_obj *tape;
3625
3626         tape = ide_tape_get(disk);
3627         if (!tape)
3628                 return -ENXIO;
3629
3630         return 0;
3631 }
3632
3633 static int idetape_release(struct inode *inode, struct file *filp)
3634 {
3635         struct gendisk *disk = inode->i_bdev->bd_disk;
3636         struct ide_tape_obj *tape = ide_tape_g(disk);
3637
3638         ide_tape_put(tape);
3639
3640         return 0;
3641 }
3642
3643 static int idetape_ioctl(struct inode *inode, struct file *file,
3644                         unsigned int cmd, unsigned long arg)
3645 {
3646         struct block_device *bdev = inode->i_bdev;
3647         struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
3648         ide_drive_t *drive = tape->drive;
3649         int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
3650         if (err == -EINVAL)
3651                 err = idetape_blkdev_ioctl(drive, cmd, arg);
3652         return err;
3653 }
3654
3655 static struct block_device_operations idetape_block_ops = {
3656         .owner          = THIS_MODULE,
3657         .open           = idetape_open,
3658         .release        = idetape_release,
3659         .ioctl          = idetape_ioctl,
3660 };
3661
3662 static int ide_tape_probe(ide_drive_t *drive)
3663 {
3664         idetape_tape_t *tape;
3665         struct gendisk *g;
3666         int minor;
3667
3668         if (!strstr("ide-tape", drive->driver_req))
3669                 goto failed;
3670         if (!drive->present)
3671                 goto failed;
3672         if (drive->media != ide_tape)
3673                 goto failed;
3674         if (!idetape_identify_device(drive)) {
3675                 printk(KERN_ERR "ide-tape: %s: not supported by this version of"
3676                                 " the driver\n", drive->name);
3677                 goto failed;
3678         }
3679         if (drive->scsi) {
3680                 printk(KERN_INFO "ide-tape: passing drive %s to ide-scsi"
3681                                  " emulation.\n", drive->name);
3682                 goto failed;
3683         }
3684         tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
3685         if (tape == NULL) {
3686                 printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",
3687                                 drive->name);
3688                 goto failed;
3689         }
3690
3691         g = alloc_disk(1 << PARTN_BITS);
3692         if (!g)
3693                 goto out_free_tape;
3694
3695         ide_init_disk(g, drive);
3696
3697         ide_proc_register_driver(drive, &idetape_driver);
3698
3699         kref_init(&tape->kref);
3700
3701         tape->drive = drive;
3702         tape->driver = &idetape_driver;
3703         tape->disk = g;
3704
3705         g->private_data = &tape->driver;
3706
3707         drive->driver_data = tape;
3708
3709         mutex_lock(&idetape_ref_mutex);
3710         for (minor = 0; idetape_devs[minor]; minor++)
3711                 ;
3712         idetape_devs[minor] = tape;
3713         mutex_unlock(&idetape_ref_mutex);
3714
3715         idetape_setup(drive, tape, minor);
3716
3717         device_create(idetape_sysfs_class, &drive->gendev,
3718                       MKDEV(IDETAPE_MAJOR, minor), "%s", tape->name);
3719         device_create(idetape_sysfs_class, &drive->gendev,
3720                         MKDEV(IDETAPE_MAJOR, minor + 128), "n%s", tape->name);
3721
3722         g->fops = &idetape_block_ops;
3723         ide_register_region(g);
3724
3725         return 0;
3726
3727 out_free_tape:
3728         kfree(tape);
3729 failed:
3730         return -ENODEV;
3731 }
3732
3733 static void __exit idetape_exit(void)
3734 {
3735         driver_unregister(&idetape_driver.gen_driver);
3736         class_destroy(idetape_sysfs_class);
3737         unregister_chrdev(IDETAPE_MAJOR, "ht");
3738 }
3739
3740 static int __init idetape_init(void)
3741 {
3742         int error = 1;
3743         idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
3744         if (IS_ERR(idetape_sysfs_class)) {
3745                 idetape_sysfs_class = NULL;
3746                 printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
3747                 error = -EBUSY;
3748                 goto out;
3749         }
3750
3751         if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
3752                 printk(KERN_ERR "ide-tape: Failed to register chrdev"
3753                                 " interface\n");
3754                 error = -EBUSY;
3755                 goto out_free_class;
3756         }
3757
3758         error = driver_register(&idetape_driver.gen_driver);
3759         if (error)
3760                 goto out_free_driver;
3761
3762         return 0;
3763
3764 out_free_driver:
3765         driver_unregister(&idetape_driver.gen_driver);
3766 out_free_class:
3767         class_destroy(idetape_sysfs_class);
3768 out:
3769         return error;
3770 }
3771
3772 MODULE_ALIAS("ide:*m-tape*");
3773 module_init(idetape_init);
3774 module_exit(idetape_exit);
3775 MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
3776 MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
3777 MODULE_LICENSE("GPL");