drivers/usb/gadget/storage_common.c

   1 /*
   2  * storage_common.c -- Common definitions for mass storage functionality
   3  *
   4  * Copyright (C) 2003-2008 Alan Stern
   5  * Copyeight (C) 2009 Samsung Electronics
   6  * Author: Michal Nazarewicz (m.nazarewicz@samsung.com)
   7  *
   8  * Ported to u-boot:
   9  * Andrzej Pietrasiewicz <andrzej.p@samsung.com>
  10  *
  11  * Code refactoring & cleanup:
  12  * Łukasz Majewski <l.majewski@samsung.com>
  13  *
  14  * SPDX-License-Identifier:     GPL-2.0+
  15  */
  16
  17
  18 /*
  19  * This file requires the following identifiers used in USB strings to
  20  * be defined (each of type pointer to char):
  21  *  - fsg_string_manufacturer -- name of the manufacturer
  22  *  - fsg_string_product      -- name of the product
  23  *  - fsg_string_serial       -- product's serial
  24  *  - fsg_string_config       -- name of the configuration
  25  *  - fsg_string_interface    -- name of the interface
  26  * The first four are only needed when FSG_DESCRIPTORS_DEVICE_STRINGS
  27  * macro is defined prior to including this file.
  28  */
  29
  30 /*
  31  * When FSG_NO_INTR_EP is defined fsg_fs_intr_in_desc and
  32  * fsg_hs_intr_in_desc objects as well as
  33  * FSG_FS_FUNCTION_PRE_EP_ENTRIES and FSG_HS_FUNCTION_PRE_EP_ENTRIES
  34  * macros are not defined.
  35  *
  36  * When FSG_NO_DEVICE_STRINGS is defined FSG_STRING_MANUFACTURER,
  37  * FSG_STRING_PRODUCT, FSG_STRING_SERIAL and FSG_STRING_CONFIG are not
  38  * defined (as well as corresponding entries in string tables are
  39  * missing) and FSG_STRING_INTERFACE has value of zero.
  40  *
  41  * When FSG_NO_OTG is defined fsg_otg_desc won't be defined.
  42  */
  43
  44 /*
  45  * When FSG_BUFFHD_STATIC_BUFFER is defined when this file is included
  46  * the fsg_buffhd structure's buf field will be an array of FSG_BUFLEN
  47  * characters rather then a pointer to void.
  48  */
  49
  50
  51 /* #include <asm/unaligned.h> */
  52
  53
  54 /*
  55  * Thanks to NetChip Technologies for donating this product ID.
  56  *
  57  * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
  58  * Instead:  allocate your own, using normal USB-IF procedures.
  59  */
  60 #define FSG_VENDOR_ID   0x0525  /* NetChip */
  61 #define FSG_PRODUCT_ID  0xa4a5  /* Linux-USB File-backed Storage Gadget */
  62
  63 /*-------------------------------------------------------------------------*/
  64
  65 #ifndef DEBUG
  66 #undef VERBOSE_DEBUG
  67 #undef DUMP_MSGS
  68 #endif /* !DEBUG */
  69
  70 #ifdef VERBOSE_DEBUG
  71 #define VLDBG   LDBG
  72 #else
  73 #define VLDBG(lun, fmt, args...) do { } while (0)
  74 #endif /* VERBOSE_DEBUG */
  75
  76 /*
  77 #define LDBG(lun, fmt, args...)   dev_dbg (&(lun)->dev, fmt, ## args)
  78 #define LERROR(lun, fmt, args...) dev_err (&(lun)->dev, fmt, ## args)
  79 #define LWARN(lun, fmt, args...)  dev_warn(&(lun)->dev, fmt, ## args)
  80 #define LINFO(lun, fmt, args...)  dev_info(&(lun)->dev, fmt, ## args)
  81 */
  82
  83 #define LDBG(lun, fmt, args...) do { } while (0)
  84 #define LERROR(lun, fmt, args...) do { } while (0)
  85 #define LWARN(lun, fmt, args...) do { } while (0)
  86 #define LINFO(lun, fmt, args...) do { } while (0)
  87
  88 /*
  89  * Keep those macros in sync with those in
  90  * include/linux/usb/composite.h or else GCC will complain.  If they
  91  * are identical (the same names of arguments, white spaces in the
  92  * same places) GCC will allow redefinition otherwise (even if some
  93  * white space is removed or added) warning will be issued.
  94  *
  95  * Those macros are needed here because File Storage Gadget does not
  96  * include the composite.h header.  For composite gadgets those macros
  97  * are redundant since composite.h is included any way.
  98  *
  99  * One could check whether those macros are already defined (which
 100  * would indicate composite.h had been included) or not (which would
 101  * indicate we were in FSG) but this is not done because a warning is
 102  * desired if definitions here differ from the ones in composite.h.
 103  *
 104  * We want the definitions to match and be the same in File Storage
 105  * Gadget as well as Mass Storage Function (and so composite gadgets
 106  * using MSF).  If someone changes them in composite.h it will produce
 107  * a warning in this file when building MSF.
 108  */
 109
 110 #define DBG(d, fmt, args...)     debug(fmt , ## args)
 111 #define VDBG(d, fmt, args...)    debug(fmt , ## args)
 112 /* #define ERROR(d, fmt, args...)   printf(fmt , ## args) */
 113 /* #define WARNING(d, fmt, args...) printf(fmt , ## args) */
 114 /* #define INFO(d, fmt, args...)    printf(fmt , ## args) */
 115
 116 /* #define DBG(d, fmt, args...)     do { } while (0) */
 117 /* #define VDBG(d, fmt, args...)    do { } while (0) */
 118 #define ERROR(d, fmt, args...)   do { } while (0)
 119 #define WARNING(d, fmt, args...) do { } while (0)
 120 #define INFO(d, fmt, args...)    do { } while (0)
 121
 122 #ifdef DUMP_MSGS
 123
 124 /* dump_msg(fsg, const char * label, const u8 * buf, unsigned length); */
 125 # define dump_msg(fsg, label, buf, length) do {                         \
 126         if (length < 512) {                                             \
 127                 DBG(fsg, "%s, length %u:\n", label, length);            \
 128                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET,      \
 129                                16, 1, buf, length, 0);                  \
 130         }                                                               \
 131 } while (0)
 132
 133 #  define dump_cdb(fsg) do { } while (0)
 134
 135 #else
 136
 137 #  define dump_msg(fsg, /* const char * */ label, \
 138                    /* const u8 * */ buf, /* unsigned */ length) do { } while (0)
 139
 140 #  ifdef VERBOSE_DEBUG
 141
 142 #    define dump_cdb(fsg)                                               \
 143         print_hex_dump(KERN_DEBUG, "SCSI CDB: ", DUMP_PREFIX_NONE,      \
 144                        16, 1, (fsg)->cmnd, (fsg)->cmnd_size, 0)         \
 145
 146 #  else
 147
 148 #    define dump_cdb(fsg) do { } while (0)
 149
 150 #  endif /* VERBOSE_DEBUG */
 151
 152 #endif /* DUMP_MSGS */
 153
 154 /*-------------------------------------------------------------------------*/
 155
 156 /* SCSI device types */
 157 #define TYPE_DISK       0x00
 158 #define TYPE_CDROM      0x05
 159
 160 /* USB protocol value = the transport method */
 161 #define USB_PR_CBI      0x00            /* Control/Bulk/Interrupt */
 162 #define USB_PR_CB       0x01            /* Control/Bulk w/o interrupt */
 163 #define USB_PR_BULK     0x50            /* Bulk-only */
 164
 165 /* USB subclass value = the protocol encapsulation */
 166 #define USB_SC_RBC      0x01            /* Reduced Block Commands (flash) */
 167 #define USB_SC_8020     0x02            /* SFF-8020i, MMC-2, ATAPI (CD-ROM) */
 168 #define USB_SC_QIC      0x03            /* QIC-157 (tape) */
 169 #define USB_SC_UFI      0x04            /* UFI (floppy) */
 170 #define USB_SC_8070     0x05            /* SFF-8070i (removable) */
 171 #define USB_SC_SCSI     0x06            /* Transparent SCSI */
 172
 173 /* Bulk-only data structures */
 174
 175 /* Command Block Wrapper */
 176 struct fsg_bulk_cb_wrap {
 177         __le32  Signature;              /* Contains 'USBC' */
 178         u32     Tag;                    /* Unique per command id */
 179         __le32  DataTransferLength;     /* Size of the data */
 180         u8      Flags;                  /* Direction in bit 7 */
 181         u8      Lun;                    /* LUN (normally 0) */
 182         u8      Length;                 /* Of the CDB, <= MAX_COMMAND_SIZE */
 183         u8      CDB[16];                /* Command Data Block */
 184 };
 185
 186 #define USB_BULK_CB_WRAP_LEN    31
 187 #define USB_BULK_CB_SIG         0x43425355      /* Spells out USBC */
 188 #define USB_BULK_IN_FLAG        0x80
 189
 190 /* Command Status Wrapper */
 191 struct bulk_cs_wrap {
 192         __le32  Signature;              /* Should = 'USBS' */
 193         u32     Tag;                    /* Same as original command */
 194         __le32  Residue;                /* Amount not transferred */
 195         u8      Status;                 /* See below */
 196 };
 197
 198 #define USB_BULK_CS_WRAP_LEN    13
 199 #define USB_BULK_CS_SIG         0x53425355      /* Spells out 'USBS' */
 200 #define USB_STATUS_PASS         0
 201 #define USB_STATUS_FAIL         1
 202 #define USB_STATUS_PHASE_ERROR  2
 203
 204 /* Bulk-only class specific requests */
 205 #define USB_BULK_RESET_REQUEST          0xff
 206 #define USB_BULK_GET_MAX_LUN_REQUEST    0xfe
 207
 208 /* CBI Interrupt data structure */
 209 struct interrupt_data {
 210         u8      bType;
 211         u8      bValue;
 212 };
 213
 214 #define CBI_INTERRUPT_DATA_LEN          2
 215
 216 /* CBI Accept Device-Specific Command request */
 217 #define USB_CBI_ADSC_REQUEST            0x00
 218
 219 /* Length of a SCSI Command Data Block */
 220 #define MAX_COMMAND_SIZE        16
 221
 222 /* SCSI commands that we recognize */
 223 #define SC_FORMAT_UNIT                  0x04
 224 #define SC_INQUIRY                      0x12
 225 #define SC_MODE_SELECT_6                0x15
 226 #define SC_MODE_SELECT_10               0x55
 227 #define SC_MODE_SENSE_6                 0x1a
 228 #define SC_MODE_SENSE_10                0x5a
 229 #define SC_PREVENT_ALLOW_MEDIUM_REMOVAL 0x1e
 230 #define SC_READ_6                       0x08
 231 #define SC_READ_10                      0x28
 232 #define SC_READ_12                      0xa8
 233 #define SC_READ_CAPACITY                0x25
 234 #define SC_READ_FORMAT_CAPACITIES       0x23
 235 #define SC_READ_HEADER                  0x44
 236 #define SC_READ_TOC                     0x43
 237 #define SC_RELEASE                      0x17
 238 #define SC_REQUEST_SENSE                0x03
 239 #define SC_RESERVE                      0x16
 240 #define SC_SEND_DIAGNOSTIC              0x1d
 241 #define SC_START_STOP_UNIT              0x1b
 242 #define SC_SYNCHRONIZE_CACHE            0x35
 243 #define SC_TEST_UNIT_READY              0x00
 244 #define SC_VERIFY                       0x2f
 245 #define SC_WRITE_6                      0x0a
 246 #define SC_WRITE_10                     0x2a
 247 #define SC_WRITE_12                     0xaa
 248
 249 /* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
 250 #define SS_NO_SENSE                             0
 251 #define SS_COMMUNICATION_FAILURE                0x040800
 252 #define SS_INVALID_COMMAND                      0x052000
 253 #define SS_INVALID_FIELD_IN_CDB                 0x052400
 254 #define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE   0x052100
 255 #define SS_LOGICAL_UNIT_NOT_SUPPORTED           0x052500
 256 #define SS_MEDIUM_NOT_PRESENT                   0x023a00
 257 #define SS_MEDIUM_REMOVAL_PREVENTED             0x055302
 258 #define SS_NOT_READY_TO_READY_TRANSITION        0x062800
 259 #define SS_RESET_OCCURRED                       0x062900
 260 #define SS_SAVING_PARAMETERS_NOT_SUPPORTED      0x053900
 261 #define SS_UNRECOVERED_READ_ERROR               0x031100
 262 #define SS_WRITE_ERROR                          0x030c02
 263 #define SS_WRITE_PROTECTED                      0x072700
 264
 265 #define SK(x)           ((u8) ((x) >> 16))      /* Sense Key byte, etc. */
 266 #define ASC(x)          ((u8) ((x) >> 8))
 267 #define ASCQ(x)         ((u8) (x))
 268
 269 struct device_attribute { int i; };
 270 #define ETOOSMALL       525
 271
 272 #include <usb_mass_storage.h>
 273
 274 /*-------------------------------------------------------------------------*/
 275
 276 struct fsg_lun {
 277         loff_t          file_length;
 278         loff_t          num_sectors;
 279
 280         unsigned int    initially_ro:1;
 281         unsigned int    ro:1;
 282         unsigned int    removable:1;
 283         unsigned int    cdrom:1;
 284         unsigned int    prevent_medium_removal:1;
 285         unsigned int    registered:1;
 286         unsigned int    info_valid:1;
 287         unsigned int    nofua:1;
 288
 289         u32             sense_data;
 290         u32             sense_data_info;
 291         u32             unit_attention_data;
 292
 293         struct device   dev;
 294 };
 295
 296 #define fsg_lun_is_open(curlun) ((curlun)->filp != NULL)
 297 #if 0
 298 static struct fsg_lun *fsg_lun_from_dev(struct device *dev)
 299 {
 300         return container_of(dev, struct fsg_lun, dev);
 301 }
 302 #endif
 303
 304 /* Big enough to hold our biggest descriptor */
 305 #define EP0_BUFSIZE     256
 306 #define DELAYED_STATUS  (EP0_BUFSIZE + 999)     /* An impossibly large value */
 307
 308 /* Number of buffers we will use.  2 is enough for double-buffering */
 309 #define FSG_NUM_BUFFERS 2
 310
 311 /* Default size of buffer length. */
 312 #define FSG_BUFLEN      ((u32)16384)
 313
 314 /* Maximal number of LUNs supported in mass storage function */
 315 #define FSG_MAX_LUNS    8
 316
 317 enum fsg_buffer_state {
 318         BUF_STATE_EMPTY = 0,
 319         BUF_STATE_FULL,
 320         BUF_STATE_BUSY
 321 };
 322
 323 struct fsg_buffhd {
 324 #ifdef FSG_BUFFHD_STATIC_BUFFER
 325         char                            buf[FSG_BUFLEN];
 326 #else
 327         void                            *buf;
 328 #endif
 329         enum fsg_buffer_state           state;
 330         struct fsg_buffhd               *next;
 331
 332         /*
 333          * The NetChip 2280 is faster, and handles some protocol faults
 334          * better, if we don't submit any short bulk-out read requests.
 335          * So we will record the intended request length here.
 336          */
 337         unsigned int                    bulk_out_intended_length;
 338
 339         struct usb_request              *inreq;
 340         int                             inreq_busy;
 341         struct usb_request              *outreq;
 342         int                             outreq_busy;
 343 };
 344
 345 enum fsg_state {
 346         /* This one isn't used anywhere */
 347         FSG_STATE_COMMAND_PHASE = -10,
 348         FSG_STATE_DATA_PHASE,
 349         FSG_STATE_STATUS_PHASE,
 350
 351         FSG_STATE_IDLE = 0,
 352         FSG_STATE_ABORT_BULK_OUT,
 353         FSG_STATE_RESET,
 354         FSG_STATE_INTERFACE_CHANGE,
 355         FSG_STATE_CONFIG_CHANGE,
 356         FSG_STATE_DISCONNECT,
 357         FSG_STATE_EXIT,
 358         FSG_STATE_TERMINATED
 359 };
 360
 361 enum data_direction {
 362         DATA_DIR_UNKNOWN = 0,
 363         DATA_DIR_FROM_HOST,
 364         DATA_DIR_TO_HOST,
 365         DATA_DIR_NONE
 366 };
 367
 368 /*-------------------------------------------------------------------------*/
 369
 370 static inline u32 get_unaligned_be24(u8 *buf)
 371 {
 372         return 0xffffff & (u32) get_unaligned_be32(buf - 1);
 373 }
 374
 375 /*-------------------------------------------------------------------------*/
 376
 377 enum {
 378 #ifndef FSG_NO_DEVICE_STRINGS
 379         FSG_STRING_MANUFACTURER = 1,
 380         FSG_STRING_PRODUCT,
 381         FSG_STRING_SERIAL,
 382         FSG_STRING_CONFIG,
 383 #endif
 384         FSG_STRING_INTERFACE
 385 };
 386
 387 #ifndef FSG_NO_OTG
 388 static struct usb_otg_descriptor
 389 fsg_otg_desc = {
 390         .bLength =              sizeof fsg_otg_desc,
 391         .bDescriptorType =      USB_DT_OTG,
 392
 393         .bmAttributes =         USB_OTG_SRP,
 394 };
 395 #endif
 396
 397 /* There is only one interface. */
 398
 399 static struct usb_interface_descriptor
 400 fsg_intf_desc = {
 401         .bLength =              sizeof fsg_intf_desc,
 402         .bDescriptorType =      USB_DT_INTERFACE,
 403
 404         .bNumEndpoints =        2,              /* Adjusted during fsg_bind() */
 405         .bInterfaceClass =      USB_CLASS_MASS_STORAGE,
 406         .bInterfaceSubClass =   USB_SC_SCSI,    /* Adjusted during fsg_bind() */
 407         .bInterfaceProtocol =   USB_PR_BULK,    /* Adjusted during fsg_bind() */
 408         .iInterface =           FSG_STRING_INTERFACE,
 409 };
 410
 411 /*
 412  * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
 413  * interrupt-in.
 414  */
 415
 416 static struct usb_endpoint_descriptor
 417 fsg_fs_bulk_in_desc = {
 418         .bLength =              USB_DT_ENDPOINT_SIZE,
 419         .bDescriptorType =      USB_DT_ENDPOINT,
 420
 421         .bEndpointAddress =     USB_DIR_IN,
 422         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 423         /* wMaxPacketSize set by autoconfiguration */
 424 };
 425
 426 static struct usb_endpoint_descriptor
 427 fsg_fs_bulk_out_desc = {
 428         .bLength =              USB_DT_ENDPOINT_SIZE,
 429         .bDescriptorType =      USB_DT_ENDPOINT,
 430
 431         .bEndpointAddress =     USB_DIR_OUT,
 432         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 433         /* wMaxPacketSize set by autoconfiguration */
 434 };
 435
 436 #ifndef FSG_NO_INTR_EP
 437
 438 static struct usb_endpoint_descriptor
 439 fsg_fs_intr_in_desc = {
 440         .bLength =              USB_DT_ENDPOINT_SIZE,
 441         .bDescriptorType =      USB_DT_ENDPOINT,
 442
 443         .bEndpointAddress =     USB_DIR_IN,
 444         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 445         .wMaxPacketSize =       cpu_to_le16(2),
 446         .bInterval =            32,     /* frames -> 32 ms */
 447 };
 448
 449 #ifndef FSG_NO_OTG
 450 #  define FSG_FS_FUNCTION_PRE_EP_ENTRIES        2
 451 #else
 452 #  define FSG_FS_FUNCTION_PRE_EP_ENTRIES        1
 453 #endif
 454
 455 #endif
 456
 457 static struct usb_descriptor_header *fsg_fs_function[] = {
 458 #ifndef FSG_NO_OTG
 459         (struct usb_descriptor_header *) &fsg_otg_desc,
 460 #endif
 461         (struct usb_descriptor_header *) &fsg_intf_desc,
 462         (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
 463         (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
 464 #ifndef FSG_NO_INTR_EP
 465         (struct usb_descriptor_header *) &fsg_fs_intr_in_desc,
 466 #endif
 467         NULL,
 468 };
 469
 470 /*
 471  * USB 2.0 devices need to expose both high speed and full speed
 472  * descriptors, unless they only run at full speed.
 473  *
 474  * That means alternate endpoint descriptors (bigger packets)
 475  * and a "device qualifier" ... plus more construction options
 476  * for the configuration descriptor.
 477  */
 478 static struct usb_endpoint_descriptor
 479 fsg_hs_bulk_in_desc = {
 480         .bLength =              USB_DT_ENDPOINT_SIZE,
 481         .bDescriptorType =      USB_DT_ENDPOINT,
 482
 483         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 484         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 485         .wMaxPacketSize =       cpu_to_le16(512),
 486 };
 487
 488 static struct usb_endpoint_descriptor
 489 fsg_hs_bulk_out_desc = {
 490         .bLength =              USB_DT_ENDPOINT_SIZE,
 491         .bDescriptorType =      USB_DT_ENDPOINT,
 492
 493         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 494         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 495         .wMaxPacketSize =       cpu_to_le16(512),
 496         .bInterval =            1,      /* NAK every 1 uframe */
 497 };
 498
 499 #ifndef FSG_NO_INTR_EP
 500
 501 static struct usb_endpoint_descriptor
 502 fsg_hs_intr_in_desc = {
 503         .bLength =              USB_DT_ENDPOINT_SIZE,
 504         .bDescriptorType =      USB_DT_ENDPOINT,
 505
 506         /* bEndpointAddress copied from fs_intr_in_desc during fsg_bind() */
 507         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 508         .wMaxPacketSize =       cpu_to_le16(2),
 509         .bInterval =            9,      /* 2**(9-1) = 256 uframes -> 32 ms */
 510 };
 511
 512 #ifndef FSG_NO_OTG
 513 #  define FSG_HS_FUNCTION_PRE_EP_ENTRIES        2
 514 #else
 515 #  define FSG_HS_FUNCTION_PRE_EP_ENTRIES        1
 516 #endif
 517
 518 #endif
 519
 520 static struct usb_descriptor_header *fsg_hs_function[] = {
 521 #ifndef FSG_NO_OTG
 522         (struct usb_descriptor_header *) &fsg_otg_desc,
 523 #endif
 524         (struct usb_descriptor_header *) &fsg_intf_desc,
 525         (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
 526         (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
 527 #ifndef FSG_NO_INTR_EP
 528         (struct usb_descriptor_header *) &fsg_hs_intr_in_desc,
 529 #endif
 530         NULL,
 531 };
 532
 533 /* Maxpacket and other transfer characteristics vary by speed. */
 534 static struct usb_endpoint_descriptor *
 535 fsg_ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
 536                 struct usb_endpoint_descriptor *hs)
 537 {
 538         if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
 539                 return hs;
 540         return fs;
 541 }
 542
 543 /* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
 544 static struct usb_string                fsg_strings[] = {
 545 #ifndef FSG_NO_DEVICE_STRINGS
 546         {FSG_STRING_MANUFACTURER,       fsg_string_manufacturer},
 547         {FSG_STRING_PRODUCT,            fsg_string_product},
 548         {FSG_STRING_SERIAL,             fsg_string_serial},
 549         {FSG_STRING_CONFIG,             fsg_string_config},
 550 #endif
 551         {FSG_STRING_INTERFACE,          fsg_string_interface},
 552         {}
 553 };
 554
 555 static struct usb_gadget_strings        fsg_stringtab = {
 556         .language       = 0x0409,               /* en-us */
 557         .strings        = fsg_strings,
 558 };
 559
 560 /*-------------------------------------------------------------------------*/
 561
 562 /*
 563  * If the next two routines are called while the gadget is registered,
 564  * the caller must own fsg->filesem for writing.
 565  */
 566
 567 static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 568 {
 569         int                             ro;
 570
 571         /* R/W if we can, R/O if we must */
 572         ro = curlun->initially_ro;
 573
 574         curlun->ro = ro;
 575         curlun->file_length = ums->num_sectors << 9;
 576         curlun->num_sectors = ums->num_sectors;
 577         debug("open backing file: %s\n", filename);
 578
 579         return 0;
 580 }
 581
 582 static void fsg_lun_close(struct fsg_lun *curlun)
 583 {
 584 }
 585
 586 /*-------------------------------------------------------------------------*/
 587
 588 /*
 589  * Sync the file data, don't bother with the metadata.
 590  * This code was copied from fs/buffer.c:sys_fdatasync().
 591  */
 592 static int fsg_lun_fsync_sub(struct fsg_lun *curlun)
 593 {
 594         return 0;
 595 }
 596
 597 static void store_cdrom_address(u8 *dest, int msf, u32 addr)
 598 {
 599         if (msf) {
 600                 /* Convert to Minutes-Seconds-Frames */
 601                 addr >>= 2;             /* Convert to 2048-byte frames */
 602                 addr += 2*75;           /* Lead-in occupies 2 seconds */
 603                 dest[3] = addr % 75;    /* Frames */
 604                 addr /= 75;
 605                 dest[2] = addr % 60;    /* Seconds */
 606                 addr /= 60;
 607                 dest[1] = addr;         /* Minutes */
 608                 dest[0] = 0;            /* Reserved */
 609         } else {
 610                 /* Absolute sector */
 611                 put_unaligned_be32(addr, dest);
 612         }
 613 }
 614
 615 /*-------------------------------------------------------------------------*/