Documentation/ioctl/hdio.txt

   1                 Summary of HDIO_ ioctl calls.
   2                 ============================
   3
   4                 Edward A. Falk <efalk@google.com>
   5
   6                 November, 2004
   7
   8 This document attempts to describe the ioctl(2) calls supported by
   9 the HD/IDE layer.  These are by-and-large implemented (as of Linux 2.6)
  10 in drivers/ide/ide.c and drivers/block/scsi_ioctl.c
  11
  12 ioctl values are listed in <linux/hdreg.h>.  As of this writing, they
  13 are as follows:
  14
  15     ioctls that pass argument pointers to user space:
  16
  17         HDIO_GETGEO             get device geometry
  18         HDIO_GET_UNMASKINTR     get current unmask setting
  19         HDIO_GET_MULTCOUNT      get current IDE blockmode setting
  20         HDIO_GET_QDMA           get use-qdma flag
  21         HDIO_SET_XFER           set transfer rate via proc
  22         HDIO_OBSOLETE_IDENTITY  OBSOLETE, DO NOT USE
  23         HDIO_GET_KEEPSETTINGS   get keep-settings-on-reset flag
  24         HDIO_GET_32BIT          get current io_32bit setting
  25         HDIO_GET_NOWERR         get ignore-write-error flag
  26         HDIO_GET_DMA            get use-dma flag
  27         HDIO_GET_NICE           get nice flags
  28         HDIO_GET_IDENTITY       get IDE identification info
  29         HDIO_GET_WCACHE         get write cache mode on|off
  30         HDIO_GET_ACOUSTIC       get acoustic value
  31         HDIO_GET_ADDRESS        get sector addressing mode
  32         HDIO_GET_BUSSTATE       get the bus state of the hwif
  33         HDIO_TRISTATE_HWIF      execute a channel tristate
  34         HDIO_DRIVE_RESET        execute a device reset
  35         HDIO_DRIVE_TASKFILE     execute raw taskfile
  36         HDIO_DRIVE_TASK         execute task and special drive command
  37         HDIO_DRIVE_CMD          execute a special drive command
  38         HDIO_DRIVE_CMD_AEB      HDIO_DRIVE_TASK
  39
  40     ioctls that pass non-pointer values:
  41
  42         HDIO_SET_MULTCOUNT      change IDE blockmode
  43         HDIO_SET_UNMASKINTR     permit other irqs during I/O
  44         HDIO_SET_KEEPSETTINGS   keep ioctl settings on reset
  45         HDIO_SET_32BIT          change io_32bit flags
  46         HDIO_SET_NOWERR         change ignore-write-error flag
  47         HDIO_SET_DMA            change use-dma flag
  48         HDIO_SET_PIO_MODE       reconfig interface to new speed
  49         HDIO_SCAN_HWIF          register and (re)scan interface
  50         HDIO_SET_NICE           set nice flags
  51         HDIO_UNREGISTER_HWIF    unregister interface
  52         HDIO_SET_WCACHE         change write cache enable-disable
  53         HDIO_SET_ACOUSTIC       change acoustic behavior
  54         HDIO_SET_BUSSTATE       set the bus state of the hwif
  55         HDIO_SET_QDMA           change use-qdma flag
  56         HDIO_SET_ADDRESS        change lba addressing modes
  57
  58         HDIO_SET_IDE_SCSI       Set scsi emulation mode on/off
  59         HDIO_SET_SCSI_IDE       not implemented yet
  60
  61
  62 The information that follows was determined from reading kernel source
  63 code.  It is likely that some corrections will be made over time.
  64
  65
  66
  67
  68
  69
  70
  71 General:
  72
  73         Unless otherwise specified, all ioctl calls return 0 on success
  74         and -1 with errno set to an appropriate value on error.
  75
  76         Unless otherwise specified, all ioctl calls return -1 and set
  77         errno to EFAULT on a failed attempt to copy data to or from user
  78         address space.
  79
  80         Unless otherwise specified, all data structures and constants
  81         are defined in <linux/hdreg.h>
  82
  83
  84
  85 HDIO_GETGEO                     get device geometry
  86
  87         usage:
  88
  89           struct hd_geometry geom;
  90           ioctl(fd, HDIO_GETGEO, &geom);
  91
  92
  93         inputs:         none
  94
  95         outputs:
  96
  97           hd_geometry structure containing:
  98
  99             heads       number of heads
 100             sectors     number of sectors/track
 101             cylinders   number of cylinders, mod 65536
 102             start       starting sector of this partition.
 103
 104
 105         error returns:
 106           EINVAL        if the device is not a disk drive or floppy drive,
 107                         or if the user passes a null pointer
 108
 109
 110         notes:
 111
 112           Not particularly useful with modern disk drives, whose geometry
 113           is a polite fiction anyway.  Modern drives are addressed
 114           purely by sector number nowadays (lba addressing), and the
 115           drive geometry is an abstraction which is actually subject
 116           to change.  Currently (as of Nov 2004), the geometry values
 117           are the "bios" values -- presumably the values the drive had
 118           when Linux first booted.
 119
 120           In addition, the cylinders field of the hd_geometry is an
 121           unsigned short, meaning that on most architectures, this
 122           ioctl will not return a meaningful value on drives with more
 123           than 65535 tracks.
 124
 125           The start field is unsigned long, meaning that it will not
 126           contain a meaningful value for disks over 219 Gb in size.
 127
 128
 129
 130
 131 HDIO_GET_UNMASKINTR             get current unmask setting
 132
 133         usage:
 134
 135           long val;
 136           ioctl(fd, HDIO_GET_UNMASKINTR, &val);
 137
 138         inputs:         none
 139
 140         outputs:
 141           The value of the drive's current unmask setting
 142
 143
 144
 145 HDIO_SET_UNMASKINTR             permit other irqs during I/O
 146
 147         usage:
 148
 149           unsigned long val;
 150           ioctl(fd, HDIO_SET_UNMASKINTR, val);
 151
 152         inputs:
 153           New value for unmask flag
 154
 155         outputs:        none
 156
 157         error return:
 158           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
 159           EACCES        Access denied:  requires CAP_SYS_ADMIN
 160           EINVAL        value out of range [0 1]
 161           EBUSY         Controller busy
 162
 163
 164
 165
 166 HDIO_GET_MULTCOUNT              get current IDE blockmode setting
 167
 168         usage:
 169
 170           long val;
 171           ioctl(fd, HDIO_GET_MULTCOUNT, &val);
 172
 173         inputs:         none
 174
 175         outputs:
 176           The value of the current IDE block mode setting.  This
 177           controls how many sectors the drive will transfer per
 178           interrupt.
 179
 180
 181
 182 HDIO_SET_MULTCOUNT              change IDE blockmode
 183
 184         usage:
 185
 186           int val;
 187           ioctl(fd, HDIO_SET_MULTCOUNT, val);
 188
 189         inputs:
 190           New value for IDE block mode setting.  This controls how many
 191           sectors the drive will transfer per interrupt.
 192
 193         outputs:        none
 194
 195         error return:
 196           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
 197           EACCES        Access denied:  requires CAP_SYS_ADMIN
 198           EINVAL        value out of range supported by disk.
 199           EBUSY         Controller busy or blockmode already set.
 200           EIO           Drive did not accept new block mode.
 201
 202         notes:
 203
 204           Source code comments read:
 205
 206             This is tightly woven into the driver->do_special cannot
 207             touch.  DON'T do it again until a total personality rewrite
 208             is committed.
 209
 210           If blockmode has already been set, this ioctl will fail with
 211           EBUSY
 212
 213
 214
 215 HDIO_GET_QDMA                   get use-qdma flag
 216
 217         Not implemented, as of 2.6.8.1
 218
 219
 220
 221 HDIO_SET_XFER                   set transfer rate via proc
 222
 223         Not implemented, as of 2.6.8.1
 224
 225
 226
 227 HDIO_OBSOLETE_IDENTITY          OBSOLETE, DO NOT USE
 228
 229         Same as HDIO_GET_IDENTITY (see below), except that it only
 230         returns the first 142 bytes of drive identity information.
 231
 232
 233
 234 HDIO_GET_IDENTITY               get IDE identification info
 235
 236         usage:
 237
 238           unsigned char identity[512];
 239           ioctl(fd, HDIO_GET_IDENTITY, identity);
 240
 241         inputs:         none
 242
 243         outputs:
 244
 245           ATA drive identity information.  For full description, see
 246           the IDENTIFY DEVICE and IDENTIFY PACKET DEVICE commands in
 247           the ATA specification.
 248
 249         error returns:
 250           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
 251           ENOMSG        IDENTIFY DEVICE information not available
 252
 253         notes:
 254
 255           Returns information that was obtained when the drive was
 256           probed.  Some of this information is subject to change, and
 257           this ioctl does not re-probe the drive to update the
 258           information.
 259
 260           This information is also available from /proc/ide/hdX/identify
 261
 262
 263
 264 HDIO_GET_KEEPSETTINGS           get keep-settings-on-reset flag
 265
 266         usage:
 267
 268           long val;
 269           ioctl(fd, HDIO_GET_KEEPSETTINGS, &val);
 270
 271         inputs:         none
 272
 273         outputs:
 274           The value of the current "keep settings" flag
 275
 276         notes:
 277
 278           When set, indicates that kernel should restore settings
 279           after a drive reset.
 280
 281
 282
 283 HDIO_SET_KEEPSETTINGS           keep ioctl settings on reset
 284
 285         usage:
 286
 287           long val;
 288           ioctl(fd, HDIO_SET_KEEPSETTINGS, val);
 289
 290         inputs:
 291           New value for keep_settings flag
 292
 293         outputs:        none
 294
 295         error return:
 296           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
 297           EACCES        Access denied:  requires CAP_SYS_ADMIN
 298           EINVAL        value out of range [0 1]
 299           EBUSY         Controller busy
 300
 301
 302
 303 HDIO_GET_32BIT                  get current io_32bit setting
 304
 305         usage:
 306
 307           long val;
 308           ioctl(fd, HDIO_GET_32BIT, &val);
 309
 310         inputs:         none
 311
 312         outputs:
 313           The value of the current io_32bit setting
 314
 315         notes:
 316
 317           0=16-bit, 1=32-bit, 2,3 = 32bit+sync
 318
 319
 320
 321 HDIO_GET_NOWERR                 get ignore-write-error flag
 322
 323         usage:
 324
 325           long val;
 326           ioctl(fd, HDIO_GET_NOWERR, &val);
 327
 328         inputs:         none
 329
 330         outputs:
 331           The value of the current ignore-write-error flag
 332
 333
 334
 335 HDIO_GET_DMA                    get use-dma flag
 336
 337         usage:
 338
 339           long val;
 340           ioctl(fd, HDIO_GET_DMA, &val);
 341
 342         inputs:         none
 343
 344         outputs:
 345           The value of the current use-dma flag
 346
 347
 348
 349 HDIO_GET_NICE                   get nice flags
 350
 351         usage:
 352
 353           long nice;
 354           ioctl(fd, HDIO_GET_NICE, &nice);
 355
 356         inputs:         none
 357
 358         outputs:
 359
 360           The drive's "nice" values.
 361
 362         notes:
 363
 364           Per-drive flags which determine when the system will give more
 365           bandwidth to other devices sharing the same IDE bus.
 366           See <linux/hdreg.h>, near symbol IDE_NICE_DSC_OVERLAP.
 367
 368
 369
 370
 371 HDIO_SET_NICE                   set nice flags
 372
 373         usage:
 374
 375           unsigned long nice;
 376           ...
 377           ioctl(fd, HDIO_SET_NICE, nice);
 378
 379         inputs:
 380           bitmask of nice flags.
 381
 382         outputs:        none
 383
 384         error returns:
 385           EACCES        Access denied:  requires CAP_SYS_ADMIN
 386           EPERM         Flags other than DSC_OVERLAP and NICE_1 set.
 387           EPERM         DSC_OVERLAP specified but not supported by drive
 388
 389         notes:
 390
 391           This ioctl sets the DSC_OVERLAP and NICE_1 flags from values
 392           provided by the user.
 393
 394           Nice flags are listed in <linux/hdreg.h>, starting with
 395           IDE_NICE_DSC_OVERLAP.  These values represent shifts.
 396
 397
 398
 399
 400
 401 HDIO_GET_WCACHE                 get write cache mode on|off
 402
 403         usage:
 404
 405           long val;
 406           ioctl(fd, HDIO_GET_WCACHE, &val);
 407
 408         inputs:         none
 409
 410         outputs:
 411           The value of the current write cache mode
 412
 413
 414
 415 HDIO_GET_ACOUSTIC               get acoustic value
 416
 417         usage:
 418
 419           long val;
 420           ioctl(fd, HDIO_GET_ACOUSTIC, &val);
 421
 422         inputs:         none
 423
 424         outputs:
 425           The value of the current acoustic settings
 426
 427         notes:
 428
 429           See HDIO_SET_ACOUSTIC
 430
 431
 432
 433 HDIO_GET_ADDRESS
 434
 435         usage:
 436
 437           long val;
 438           ioctl(fd, HDIO_GET_ADDRESS, &val);
 439
 440         inputs:         none
 441
 442         outputs:
 443           The value of the current addressing mode:
 444             0 = 28-bit
 445             1 = 48-bit
 446             2 = 48-bit doing 28-bit
 447             3 = 64-bit
 448
 449
 450
 451 HDIO_GET_BUSSTATE               get the bus state of the hwif
 452
 453         usage:
 454
 455           long state;
 456           ioctl(fd, HDIO_SCAN_HWIF, &state);
 457
 458         inputs:         none
 459
 460         outputs:
 461           Current power state of the IDE bus.  One of BUSSTATE_OFF,
 462           BUSSTATE_ON, or BUSSTATE_TRISTATE
 463
 464         error returns:
 465           EACCES        Access denied:  requires CAP_SYS_ADMIN
 466
 467
 468
 469
 470 HDIO_SET_BUSSTATE               set the bus state of the hwif
 471
 472         usage:
 473
 474           int state;
 475           ...
 476           ioctl(fd, HDIO_SCAN_HWIF, state);
 477
 478         inputs:
 479           Desired IDE power state.  One of BUSSTATE_OFF, BUSSTATE_ON,
 480           or BUSSTATE_TRISTATE
 481
 482         outputs:        none
 483
 484         error returns:
 485           EACCES        Access denied:  requires CAP_SYS_RAWIO
 486           EOPNOTSUPP    Hardware interface does not support bus power control
 487
 488
 489
 490
 491 HDIO_TRISTATE_HWIF              execute a channel tristate
 492
 493         Not implemented, as of 2.6.8.1.  See HDIO_SET_BUSSTATE
 494
 495
 496
 497 HDIO_DRIVE_RESET                execute a device reset
 498
 499         usage:
 500
 501           int args[3]
 502           ...
 503           ioctl(fd, HDIO_DRIVE_RESET, args);
 504
 505         inputs:         none
 506
 507         outputs:        none
 508
 509         error returns:
 510           EACCES        Access denied:  requires CAP_SYS_ADMIN
 511
 512         notes:
 513
 514           Execute a reset on the device as soon as the current IO
 515           operation has completed.
 516
 517           Executes an ATAPI soft reset if applicable, otherwise
 518           executes an ATA soft reset on the controller.
 519
 520
 521
 522 HDIO_DRIVE_TASKFILE             execute raw taskfile
 523
 524         Note:  If you don't have a copy of the ANSI ATA specification
 525         handy, you should probably ignore this ioctl.
 526
 527         Execute an ATA disk command directly by writing the "taskfile"
 528         registers of the drive.  Requires ADMIN and RAWIO access
 529         privileges.
 530
 531         usage:
 532
 533           struct {
 534             ide_task_request_t req_task;
 535             u8 outbuf[OUTPUT_SIZE];
 536             u8 inbuf[INPUT_SIZE];
 537           } task;
 538           memset(&task.req_task, 0, sizeof(task.req_task));
 539           task.req_task.out_size = sizeof(task.outbuf);
 540           task.req_task.in_size = sizeof(task.inbuf);
 541           ...
 542           ioctl(fd, HDIO_DRIVE_TASKFILE, &task);
 543           ...
 544
 545         inputs:
 546
 547           (See below for details on memory area passed to ioctl.)
 548
 549           io_ports[8]   values to be written to taskfile registers
 550           hob_ports[8]  high-order bytes, for extended commands.
 551           out_flags     flags indicating which registers are valid
 552           in_flags      flags indicating which registers should be returned
 553           data_phase    see below
 554           req_cmd       command type to be executed
 555           out_size      size of output buffer
 556           outbuf        buffer of data to be transmitted to disk
 557           inbuf         buffer of data to be received from disk (see [1])
 558
 559         outputs:
 560
 561           io_ports[]    values returned in the taskfile registers
 562           hob_ports[]   high-order bytes, for extended commands.
 563           out_flags     flags indicating which registers are valid (see [2])
 564           in_flags      flags indicating which registers should be returned
 565           outbuf        buffer of data to be transmitted to disk (see [1])
 566           inbuf         buffer of data to be received from disk
 567
 568         error returns:
 569           EACCES        CAP_SYS_ADMIN or CAP_SYS_RAWIO privilege not set.
 570           ENOMSG        Device is not a disk drive.
 571           ENOMEM        Unable to allocate memory for task
 572           EFAULT        req_cmd == TASKFILE_IN_OUT (not implemented as of 2.6.8)
 573           EPERM         req_cmd == TASKFILE_MULTI_OUT and drive
 574                         multi-count not yet set.
 575           EIO           Drive failed the command.
 576
 577         notes:
 578
 579           [1] READ THE FOLLOWING NOTES *CAREFULLY*.  THIS IOCTL IS
 580           FULL OF GOTCHAS.  Extreme caution should be used with using
 581           this ioctl.  A mistake can easily corrupt data or hang the
 582           system.
 583
 584           [2] Both the input and output buffers are copied from the
 585           user and written back to the user, even when not used.
 586
 587           [3] If one or more bits are set in out_flags and in_flags is
 588           zero, the following values are used for in_flags.all and
 589           written back into in_flags on completion.
 590
 591            * IDE_TASKFILE_STD_IN_FLAGS | (IDE_HOB_STD_IN_FLAGS << 8)
 592              if LBA48 addressing is enabled for the drive
 593            * IDE_TASKFILE_STD_IN_FLAGS
 594              if CHS/LBA28
 595
 596           The association between in_flags.all and each enable
 597           bitfield flips depending on endianess; fortunately, TASKFILE
 598           only uses inflags.b.data bit and ignores all other bits.
 599           The end result is that, on any endian machines, it has no
 600           effect other than modifying in_flags on completion.
 601
 602           [4] The default value of SELECT is (0xa0|DEV_bit|LBA_bit)
 603           except for four drives per port chipsets.  For four drives
 604           per port chipsets, it's (0xa0|DEV_bit|LBA_bit) for the first
 605           pair and (0x80|DEV_bit|LBA_bit) for the second pair.
 606
 607           [5] The argument to the ioctl is a pointer to a region of
 608           memory containing a ide_task_request_t structure, followed
 609           by an optional buffer of data to be transmitted to the
 610           drive, followed by an optional buffer to receive data from
 611           the drive.
 612
 613           Command is passed to the disk drive via the ide_task_request_t
 614           structure, which contains these fields:
 615
 616             io_ports[8]         values for the taskfile registers
 617             hob_ports[8]        high-order bytes, for extended commands
 618             out_flags           flags indicating which entries in the
 619                                 io_ports[] and hob_ports[] arrays
 620                                 contain valid values.  Type ide_reg_valid_t.
 621             in_flags            flags indicating which entries in the
 622                                 io_ports[] and hob_ports[] arrays
 623                                 are expected to contain valid values
 624                                 on return.
 625             data_phase          See below
 626             req_cmd             Command type, see below
 627             out_size            output (user->drive) buffer size, bytes
 628             in_size             input (drive->user) buffer size, bytes
 629
 630           When out_flags is zero, the following registers are loaded.
 631
 632             HOB_FEATURE         If the drive supports LBA48
 633             HOB_NSECTOR         If the drive supports LBA48
 634             HOB_SECTOR          If the drive supports LBA48
 635             HOB_LCYL            If the drive supports LBA48
 636             HOB_HCYL            If the drive supports LBA48
 637             FEATURE
 638             NSECTOR
 639             SECTOR
 640             LCYL
 641             HCYL
 642             SELECT              First, masked with 0xE0 if LBA48, 0xEF
 643                                 otherwise; then, or'ed with the default
 644                                 value of SELECT.
 645
 646           If any bit in out_flags is set, the following registers are loaded.
 647
 648             HOB_DATA            If out_flags.b.data is set.  HOB_DATA will
 649                                 travel on DD8-DD15 on little endian machines
 650                                 and on DD0-DD7 on big endian machines.
 651             DATA                If out_flags.b.data is set.  DATA will
 652                                 travel on DD0-DD7 on little endian machines
 653                                 and on DD8-DD15 on big endian machines.
 654             HOB_NSECTOR         If out_flags.b.nsector_hob is set
 655             HOB_SECTOR          If out_flags.b.sector_hob is set
 656             HOB_LCYL            If out_flags.b.lcyl_hob is set
 657             HOB_HCYL            If out_flags.b.hcyl_hob is set
 658             FEATURE             If out_flags.b.feature is set
 659             NSECTOR             If out_flags.b.nsector is set
 660             SECTOR              If out_flags.b.sector is set
 661             LCYL                If out_flags.b.lcyl is set
 662             HCYL                If out_flags.b.hcyl is set
 663             SELECT              Or'ed with the default value of SELECT and
 664                                 loaded regardless of out_flags.b.select.
 665
 666           Taskfile registers are read back from the drive into
 667           {io|hob}_ports[] after the command completes iff one of the
 668           following conditions is met; otherwise, the original values
 669           will be written back, unchanged.
 670
 671             1. The drive fails the command (EIO).
 672             2. One or more than one bits are set in out_flags.
 673             3. The requested data_phase is TASKFILE_NO_DATA.
 674
 675             HOB_DATA            If in_flags.b.data is set.  It will contain
 676                                 DD8-DD15 on little endian machines and
 677                                 DD0-DD7 on big endian machines.
 678             DATA                If in_flags.b.data is set.  It will contain
 679                                 DD0-DD7 on little endian machines and
 680                                 DD8-DD15 on big endian machines.
 681             HOB_FEATURE         If the drive supports LBA48
 682             HOB_NSECTOR         If the drive supports LBA48
 683             HOB_SECTOR          If the drive supports LBA48
 684             HOB_LCYL            If the drive supports LBA48
 685             HOB_HCYL            If the drive supports LBA48
 686             NSECTOR
 687             SECTOR
 688             LCYL
 689             HCYL
 690
 691           The data_phase field describes the data transfer to be
 692           performed.  Value is one of:
 693
 694             TASKFILE_IN
 695             TASKFILE_MULTI_IN
 696             TASKFILE_OUT
 697             TASKFILE_MULTI_OUT
 698             TASKFILE_IN_OUT
 699             TASKFILE_IN_DMA
 700             TASKFILE_IN_DMAQ            == IN_DMA (queueing not supported)
 701             TASKFILE_OUT_DMA
 702             TASKFILE_OUT_DMAQ           == OUT_DMA (queueing not supported)
 703             TASKFILE_P_IN               unimplemented
 704             TASKFILE_P_IN_DMA           unimplemented
 705             TASKFILE_P_IN_DMAQ          unimplemented
 706             TASKFILE_P_OUT              unimplemented
 707             TASKFILE_P_OUT_DMA          unimplemented
 708             TASKFILE_P_OUT_DMAQ         unimplemented
 709
 710           The req_cmd field classifies the command type.  It may be
 711           one of:
 712
 713             IDE_DRIVE_TASK_NO_DATA
 714             IDE_DRIVE_TASK_SET_XFER     unimplemented
 715             IDE_DRIVE_TASK_IN
 716             IDE_DRIVE_TASK_OUT          unimplemented
 717             IDE_DRIVE_TASK_RAW_WRITE
 718
 719           [6] Do not access {in|out}_flags->all except for resetting
 720           all the bits.  Always access individual bit fields.  ->all
 721           value will flip depending on endianess.  For the same
 722           reason, do not use IDE_{TASKFILE|HOB}_STD_{OUT|IN}_FLAGS
 723           constants defined in hdreg.h.
 724
 725
 726
 727 HDIO_DRIVE_CMD                  execute a special drive command
 728
 729         Note:  If you don't have a copy of the ANSI ATA specification
 730         handy, you should probably ignore this ioctl.
 731
 732         usage:
 733
 734           u8 args[4+XFER_SIZE];
 735           ...
 736           ioctl(fd, HDIO_DRIVE_CMD, args);
 737
 738         inputs:
 739
 740           Commands other than WIN_SMART
 741             args[0]     COMMAND
 742             args[1]     NSECTOR
 743             args[2]     FEATURE
 744             args[3]     NSECTOR
 745
 746           WIN_SMART
 747             args[0]     COMMAND
 748             args[1]     SECTOR
 749             args[2]     FEATURE
 750             args[3]     NSECTOR
 751
 752         outputs:
 753
 754           args[] buffer is filled with register values followed by any
 755           data returned by the disk.
 756             args[0]     status
 757             args[1]     error
 758             args[2]     NSECTOR
 759             args[3]     undefined
 760             args[4+]    NSECTOR * 512 bytes of data returned by the command.
 761
 762         error returns:
 763           EACCES        Access denied:  requires CAP_SYS_RAWIO
 764           ENOMEM        Unable to allocate memory for task
 765           EIO           Drive reports error
 766
 767         notes:
 768
 769           [1] For commands other than WIN_SMART, args[1] should equal
 770           args[3].  SECTOR, LCYL and HCYL are undefined.  For
 771           WIN_SMART, 0x4f and 0xc2 are loaded into LCYL and HCYL
 772           respectively.  In both cases SELECT will contain the default
 773           value for the drive.  Please refer to HDIO_DRIVE_TASKFILE
 774           notes for the default value of SELECT.
 775
 776           [2] If NSECTOR value is greater than zero and the drive sets
 777           DRQ when interrupting for the command, NSECTOR * 512 bytes
 778           are read from the device into the area following NSECTOR.
 779           In the above example, the area would be
 780           args[4..4+XFER_SIZE].  16bit PIO is used regardless of
 781           HDIO_SET_32BIT setting.
 782
 783           [3] If COMMAND == WIN_SETFEATURES && FEATURE == SETFEATURES_XFER
 784           && NSECTOR >= XFER_SW_DMA_0 && the drive supports any DMA
 785           mode, IDE driver will try to tune the transfer mode of the
 786           drive accordingly.
 787
 788
 789
 790 HDIO_DRIVE_TASK                 execute task and special drive command
 791
 792         Note:  If you don't have a copy of the ANSI ATA specification
 793         handy, you should probably ignore this ioctl.
 794
 795         usage:
 796
 797           u8 args[7];
 798           ...
 799           ioctl(fd, HDIO_DRIVE_TASK, args);
 800
 801         inputs:
 802
 803           Taskfile register values:
 804             args[0]     COMMAND
 805             args[1]     FEATURE
 806             args[2]     NSECTOR
 807             args[3]     SECTOR
 808             args[4]     LCYL
 809             args[5]     HCYL
 810             args[6]     SELECT
 811
 812         outputs:
 813
 814           Taskfile register values:
 815             args[0]     status
 816             args[1]     error
 817             args[2]     NSECTOR
 818             args[3]     SECTOR
 819             args[4]     LCYL
 820             args[5]     HCYL
 821             args[6]     SELECT
 822
 823         error returns:
 824           EACCES        Access denied:  requires CAP_SYS_RAWIO
 825           ENOMEM        Unable to allocate memory for task
 826           ENOMSG        Device is not a disk drive.
 827           EIO           Drive failed the command.
 828
 829         notes:
 830
 831           [1] DEV bit (0x10) of SELECT register is ignored and the
 832           appropriate value for the drive is used.  All other bits
 833           are used unaltered.
 834
 835
 836
 837 HDIO_DRIVE_CMD_AEB              HDIO_DRIVE_TASK
 838
 839         Not implemented, as of 2.6.8.1
 840
 841
 842
 843 HDIO_SET_32BIT                  change io_32bit flags
 844
 845         usage:
 846
 847           int val;
 848           ioctl(fd, HDIO_SET_32BIT, val);
 849
 850         inputs:
 851           New value for io_32bit flag
 852
 853         outputs:        none
 854
 855         error return:
 856           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
 857           EACCES        Access denied:  requires CAP_SYS_ADMIN
 858           EINVAL        value out of range [0 3]
 859           EBUSY         Controller busy
 860
 861
 862
 863
 864 HDIO_SET_NOWERR                 change ignore-write-error flag
 865
 866         usage:
 867
 868           int val;
 869           ioctl(fd, HDIO_SET_NOWERR, val);
 870
 871         inputs:
 872           New value for ignore-write-error flag.  Used for ignoring
 873           WRERR_STAT
 874
 875         outputs:        none
 876
 877         error return:
 878           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
 879           EACCES        Access denied:  requires CAP_SYS_ADMIN
 880           EINVAL        value out of range [0 1]
 881           EBUSY         Controller busy
 882
 883
 884
 885 HDIO_SET_DMA                    change use-dma flag
 886
 887         usage:
 888
 889           long val;
 890           ioctl(fd, HDIO_SET_DMA, val);
 891
 892         inputs:
 893           New value for use-dma flag
 894
 895         outputs:        none
 896
 897         error return:
 898           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
 899           EACCES        Access denied:  requires CAP_SYS_ADMIN
 900           EINVAL        value out of range [0 1]
 901           EBUSY         Controller busy
 902
 903
 904
 905 HDIO_SET_PIO_MODE               reconfig interface to new speed
 906
 907         usage:
 908
 909           long val;
 910           ioctl(fd, HDIO_SET_PIO_MODE, val);
 911
 912         inputs:
 913           New interface speed.
 914
 915         outputs:        none
 916
 917         error return:
 918           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
 919           EACCES        Access denied:  requires CAP_SYS_ADMIN
 920           EINVAL        value out of range [0 255]
 921           EBUSY         Controller busy
 922
 923
 924
 925 HDIO_SCAN_HWIF                  register and (re)scan interface
 926
 927         usage:
 928
 929           int args[3]
 930           ...
 931           ioctl(fd, HDIO_SCAN_HWIF, args);
 932
 933         inputs:
 934           args[0]       io address to probe
 935           args[1]       control address to probe
 936           args[2]       irq number
 937
 938         outputs:        none
 939
 940         error returns:
 941           EACCES        Access denied:  requires CAP_SYS_RAWIO
 942           EIO           Probe failed.
 943
 944         notes:
 945
 946           This ioctl initializes the addresses and irq for a disk
 947           controller, probes for drives, and creates /proc/ide
 948           interfaces as appropriate.
 949
 950
 951
 952 HDIO_UNREGISTER_HWIF            unregister interface
 953
 954         usage:
 955
 956           int index;
 957           ioctl(fd, HDIO_UNREGISTER_HWIF, index);
 958
 959         inputs:
 960           index         index of hardware interface to unregister
 961
 962         outputs:        none
 963
 964         error returns:
 965           EACCES        Access denied:  requires CAP_SYS_RAWIO
 966
 967         notes:
 968
 969           This ioctl removes a hardware interface from the kernel.
 970
 971           Currently (2.6.8) this ioctl silently fails if any drive on
 972           the interface is busy.
 973
 974
 975
 976 HDIO_SET_WCACHE                 change write cache enable-disable
 977
 978         usage:
 979
 980           int val;
 981           ioctl(fd, HDIO_SET_WCACHE, val);
 982
 983         inputs:
 984           New value for write cache enable
 985
 986         outputs:        none
 987
 988         error return:
 989           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
 990           EACCES        Access denied:  requires CAP_SYS_ADMIN
 991           EINVAL        value out of range [0 1]
 992           EBUSY         Controller busy
 993
 994
 995
 996 HDIO_SET_ACOUSTIC               change acoustic behavior
 997
 998         usage:
 999
1000           int val;
1001           ioctl(fd, HDIO_SET_ACOUSTIC, val);
1002
1003         inputs:
1004           New value for drive acoustic settings
1005
1006         outputs:        none
1007
1008         error return:
1009           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
1010           EACCES        Access denied:  requires CAP_SYS_ADMIN
1011           EINVAL        value out of range [0 254]
1012           EBUSY         Controller busy
1013
1014
1015
1016 HDIO_SET_QDMA                   change use-qdma flag
1017
1018         Not implemented, as of 2.6.8.1
1019
1020
1021
1022 HDIO_SET_ADDRESS                change lba addressing modes
1023
1024         usage:
1025
1026           int val;
1027           ioctl(fd, HDIO_SET_ADDRESS, val);
1028
1029         inputs:
1030           New value for addressing mode
1031             0 = 28-bit
1032             1 = 48-bit
1033             2 = 48-bit doing 28-bit
1034
1035         outputs:        none
1036
1037         error return:
1038           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
1039           EACCES        Access denied:  requires CAP_SYS_ADMIN
1040           EINVAL        value out of range [0 2]
1041           EBUSY         Controller busy
1042           EIO           Drive does not support lba48 mode.
1043
1044
1045 HDIO_SET_IDE_SCSI
1046
1047         usage:
1048
1049           long val;
1050           ioctl(fd, HDIO_SET_IDE_SCSI, val);
1051
1052         inputs:
1053           New value for scsi emulation mode (?)
1054
1055         outputs:        none
1056
1057         error return:
1058           EINVAL        (bdev != bdev->bd_contains) (not sure what this means)
1059           EACCES        Access denied:  requires CAP_SYS_ADMIN
1060           EINVAL        value out of range [0 1]
1061           EBUSY         Controller busy
1062
1063
1064
1065 HDIO_SET_SCSI_IDE
1066
1067         Not implemented, as of 2.6.8.1
1068
1069