uboot/drivers/usb/gadget/storage_common.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * storage_common.c -- Common definitions for mass storage functionality
   4 *
   5 * Copyright (C) 2003-2008 Alan Stern
   6 * Copyeight (C) 2009 Samsung Electronics
   7 * Author: Michal Nazarewicz (m.nazarewicz@samsung.com)
   8 *
   9 * Ported to u-boot:
  10 * Andrzej Pietrasiewicz <andrzej.p@samsung.com>
  11 *
  12 * Code refactoring & cleanup:
  13 * Łukasz Majewski <l.majewski@samsung.com>
  14 */
  15
  16
  17/*
  18 * This file requires the following identifiers used in USB strings to
  19 * be defined (each of type pointer to char):
  20 *  - fsg_string_manufacturer -- name of the manufacturer
  21 *  - fsg_string_product      -- name of the product
  22 *  - fsg_string_serial       -- product's serial
  23 *  - fsg_string_config       -- name of the configuration
  24 *  - fsg_string_interface    -- name of the interface
  25 * The first four are only needed when FSG_DESCRIPTORS_DEVICE_STRINGS
  26 * macro is defined prior to including this file.
  27 */
  28
  29/*
  30 * When FSG_NO_INTR_EP is defined fsg_fs_intr_in_desc and
  31 * fsg_hs_intr_in_desc objects as well as
  32 * FSG_FS_FUNCTION_PRE_EP_ENTRIES and FSG_HS_FUNCTION_PRE_EP_ENTRIES
  33 * macros are not defined.
  34 *
  35 * When FSG_NO_DEVICE_STRINGS is defined FSG_STRING_MANUFACTURER,
  36 * FSG_STRING_PRODUCT, FSG_STRING_SERIAL and FSG_STRING_CONFIG are not
  37 * defined (as well as corresponding entries in string tables are
  38 * missing) and FSG_STRING_INTERFACE has value of zero.
  39 *
  40 * When FSG_NO_OTG is defined fsg_otg_desc won't be defined.
  41 */
  42
  43/*
  44 * When FSG_BUFFHD_STATIC_BUFFER is defined when this file is included
  45 * the fsg_buffhd structure's buf field will be an array of FSG_BUFLEN
  46 * characters rather then a pointer to void.
  47 */
  48
  49
  50/* #include <asm/unaligned.h> */
  51
  52
  53/*
  54 * Thanks to NetChip Technologies for donating this product ID.
  55 *
  56 * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
  57 * Instead:  allocate your own, using normal USB-IF procedures.
  58 */
  59#define FSG_VENDOR_ID   0x0525  /* NetChip */
  60#define FSG_PRODUCT_ID  0xa4a5  /* Linux-USB File-backed Storage Gadget */
  61
  62/*-------------------------------------------------------------------------*/
  63
  64#ifndef DEBUG
  65#undef VERBOSE_DEBUG
  66#undef DUMP_MSGS
  67#endif /* !DEBUG */
  68
  69#ifdef VERBOSE_DEBUG
  70#define VLDBG   LDBG
  71#else
  72#define VLDBG(lun, fmt, args...) do { } while (0)
  73#endif /* VERBOSE_DEBUG */
  74
  75/*
  76#define LDBG(lun, fmt, args...)   dev_dbg (&(lun)->dev, fmt, ## args)
  77#define LERROR(lun, fmt, args...) dev_err (&(lun)->dev, fmt, ## args)
  78#define LWARN(lun, fmt, args...)  dev_warn(&(lun)->dev, fmt, ## args)
  79#define LINFO(lun, fmt, args...)  dev_info(&(lun)->dev, fmt, ## args)
  80*/
  81
  82#define LDBG(lun, fmt, args...) do { } while (0)
  83#define LERROR(lun, fmt, args...) do { } while (0)
  84#define LWARN(lun, fmt, args...) do { } while (0)
  85#define LINFO(lun, fmt, args...) do { } while (0)
  86
  87/*
  88 * Keep those macros in sync with those in
  89 * include/linux/usb/composite.h or else GCC will complain.  If they
  90 * are identical (the same names of arguments, white spaces in the
  91 * same places) GCC will allow redefinition otherwise (even if some
  92 * white space is removed or added) warning will be issued.
  93 *
  94 * Those macros are needed here because File Storage Gadget does not
  95 * include the composite.h header.  For composite gadgets those macros
  96 * are redundant since composite.h is included any way.
  97 *
  98 * One could check whether those macros are already defined (which
  99 * would indicate composite.h had been included) or not (which would
 100 * indicate we were in FSG) but this is not done because a warning is
 101 * desired if definitions here differ from the ones in composite.h.
 102 *
 103 * We want the definitions to match and be the same in File Storage
 104 * Gadget as well as Mass Storage Function (and so composite gadgets
 105 * using MSF).  If someone changes them in composite.h it will produce
 106 * a warning in this file when building MSF.
 107 */
 108
 109#define DBG(d, fmt, args...)     debug(fmt , ## args)
 110#define VDBG(d, fmt, args...)    debug(fmt , ## args)
 111/* #define ERROR(d, fmt, args...)   printf(fmt , ## args) */
 112/* #define WARNING(d, fmt, args...) printf(fmt , ## args) */
 113/* #define INFO(d, fmt, args...)    printf(fmt , ## args) */
 114
 115/* #define DBG(d, fmt, args...)     do { } while (0) */
 116/* #define VDBG(d, fmt, args...)    do { } while (0) */
 117#define ERROR(d, fmt, args...)   do { } while (0)
 118#define WARNING(d, fmt, args...) do { } while (0)
 119#define INFO(d, fmt, args...)    do { } while (0)
 120
 121#ifdef DUMP_MSGS
 122
 123/* dump_msg(fsg, const char * label, const u8 * buf, unsigned length); */
 124# define dump_msg(fsg, label, buf, length) do {                         \
 125        if (length < 512) {                                             \
 126                DBG(fsg, "%s, length %u:\n", label, length);            \
 127                print_hex_dump("", DUMP_PREFIX_OFFSET,  \
 128                               16, 1, buf, length, 0);                  \
 129        }                                                               \
 130} while (0)
 131
 132#  define dump_cdb(fsg) do { } while (0)
 133
 134#else
 135
 136#  define dump_msg(fsg, /* const char * */ label, \
 137                   /* const u8 * */ buf, /* unsigned */ length) do { } while (0)
 138
 139#  ifdef VERBOSE_DEBUG
 140
 141#    define dump_cdb(fsg)                                               \
 142        print_hex_dump("SCSI CDB: ", DUMP_PREFIX_NONE,  \
 143                       16, 1, (fsg)->cmnd, (fsg)->cmnd_size, 0)         \
 144
 145#  else
 146
 147#    define dump_cdb(fsg) do { } while (0)
 148
 149#  endif /* VERBOSE_DEBUG */
 150
 151#endif /* DUMP_MSGS */
 152
 153/*-------------------------------------------------------------------------*/
 154
 155/* SCSI device types */
 156#define TYPE_DISK       0x00
 157#define TYPE_CDROM      0x05
 158
 159/* USB protocol value = the transport method */
 160#define USB_PR_CBI      0x00            /* Control/Bulk/Interrupt */
 161#define USB_PR_CB       0x01            /* Control/Bulk w/o interrupt */
 162#define USB_PR_BULK     0x50            /* Bulk-only */
 163
 164/* USB subclass value = the protocol encapsulation */
 165#define USB_SC_RBC      0x01            /* Reduced Block Commands (flash) */
 166#define USB_SC_8020     0x02            /* SFF-8020i, MMC-2, ATAPI (CD-ROM) */
 167#define USB_SC_QIC      0x03            /* QIC-157 (tape) */
 168#define USB_SC_UFI      0x04            /* UFI (floppy) */
 169#define USB_SC_8070     0x05            /* SFF-8070i (removable) */
 170#define USB_SC_SCSI     0x06            /* Transparent SCSI */
 171
 172/* Bulk-only data structures */
 173
 174/* Command Block Wrapper */
 175struct fsg_bulk_cb_wrap {
 176        __le32  Signature;              /* Contains 'USBC' */
 177        u32     Tag;                    /* Unique per command id */
 178        __le32  DataTransferLength;     /* Size of the data */
 179        u8      Flags;                  /* Direction in bit 7 */
 180        u8      Lun;                    /* LUN (normally 0) */
 181        u8      Length;                 /* Of the CDB, <= MAX_COMMAND_SIZE */
 182        u8      CDB[16];                /* Command Data Block */
 183};
 184
 185#define USB_BULK_CB_WRAP_LEN    31
 186#define USB_BULK_CB_SIG         0x43425355      /* Spells out USBC */
 187#define USB_BULK_IN_FLAG        0x80
 188
 189/* Command Status Wrapper */
 190struct bulk_cs_wrap {
 191        __le32  Signature;              /* Should = 'USBS' */
 192        u32     Tag;                    /* Same as original command */
 193        __le32  Residue;                /* Amount not transferred */
 194        u8      Status;                 /* See below */
 195};
 196
 197#define USB_BULK_CS_WRAP_LEN    13
 198#define USB_BULK_CS_SIG         0x53425355      /* Spells out 'USBS' */
 199#define USB_STATUS_PASS         0
 200#define USB_STATUS_FAIL         1
 201#define USB_STATUS_PHASE_ERROR  2
 202
 203/* Bulk-only class specific requests */
 204#define USB_BULK_RESET_REQUEST          0xff
 205#define USB_BULK_GET_MAX_LUN_REQUEST    0xfe
 206
 207/* CBI Interrupt data structure */
 208struct interrupt_data {
 209        u8      bType;
 210        u8      bValue;
 211};
 212
 213#define CBI_INTERRUPT_DATA_LEN          2
 214
 215/* CBI Accept Device-Specific Command request */
 216#define USB_CBI_ADSC_REQUEST            0x00
 217
 218/* Length of a SCSI Command Data Block */
 219#define MAX_COMMAND_SIZE        16
 220
 221/* SCSI commands that we recognize */
 222#define SC_FORMAT_UNIT                  0x04
 223#define SC_INQUIRY                      0x12
 224#define SC_MODE_SELECT_6                0x15
 225#define SC_MODE_SELECT_10               0x55
 226#define SC_MODE_SENSE_6                 0x1a
 227#define SC_MODE_SENSE_10                0x5a
 228#define SC_PREVENT_ALLOW_MEDIUM_REMOVAL 0x1e
 229#define SC_READ_6                       0x08
 230#define SC_READ_10                      0x28
 231#define SC_READ_12                      0xa8
 232#define SC_READ_CAPACITY                0x25
 233#define SC_READ_FORMAT_CAPACITIES       0x23
 234#define SC_READ_HEADER                  0x44
 235#define SC_READ_TOC                     0x43
 236#define SC_RELEASE                      0x17
 237#define SC_REQUEST_SENSE                0x03
 238#define SC_RESERVE                      0x16
 239#define SC_SEND_DIAGNOSTIC              0x1d
 240#define SC_START_STOP_UNIT              0x1b
 241#define SC_SYNCHRONIZE_CACHE            0x35
 242#define SC_TEST_UNIT_READY              0x00
 243#define SC_VERIFY                       0x2f
 244#define SC_WRITE_6                      0x0a
 245#define SC_WRITE_10                     0x2a
 246#define SC_WRITE_12                     0xaa
 247
 248/* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
 249#define SS_NO_SENSE                             0
 250#define SS_COMMUNICATION_FAILURE                0x040800
 251#define SS_INVALID_COMMAND                      0x052000
 252#define SS_INVALID_FIELD_IN_CDB                 0x052400
 253#define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE   0x052100
 254#define SS_LOGICAL_UNIT_NOT_SUPPORTED           0x052500
 255#define SS_MEDIUM_NOT_PRESENT                   0x023a00
 256#define SS_MEDIUM_REMOVAL_PREVENTED             0x055302
 257#define SS_NOT_READY_TO_READY_TRANSITION        0x062800
 258#define SS_RESET_OCCURRED                       0x062900
 259#define SS_SAVING_PARAMETERS_NOT_SUPPORTED      0x053900
 260#define SS_UNRECOVERED_READ_ERROR               0x031100
 261#define SS_WRITE_ERROR                          0x030c02
 262#define SS_WRITE_PROTECTED                      0x072700
 263
 264#define SK(x)           ((u8) ((x) >> 16))      /* Sense Key byte, etc. */
 265#define ASC(x)          ((u8) ((x) >> 8))
 266#define ASCQ(x)         ((u8) (x))
 267
 268struct device_attribute { int i; };
 269#define ETOOSMALL       525
 270
 271#include <log.h>
 272#include <usb_mass_storage.h>
 273#include <dm/device_compat.h>
 274
 275/*-------------------------------------------------------------------------*/
 276
 277struct fsg_lun {
 278        loff_t          file_length;
 279        loff_t          num_sectors;
 280
 281        unsigned int    initially_ro:1;
 282        unsigned int    ro:1;
 283        unsigned int    removable:1;
 284        unsigned int    cdrom:1;
 285        unsigned int    prevent_medium_removal:1;
 286        unsigned int    registered:1;
 287        unsigned int    info_valid:1;
 288        unsigned int    nofua:1;
 289
 290        u32             sense_data;
 291        u32             sense_data_info;
 292        u32             unit_attention_data;
 293
 294        struct device   dev;
 295};
 296
 297#define fsg_lun_is_open(curlun) ((curlun)->filp != NULL)
 298#if 0
 299static struct fsg_lun *fsg_lun_from_dev(struct device *dev)
 300{
 301        return container_of(dev, struct fsg_lun, dev);
 302}
 303#endif
 304
 305/* Big enough to hold our biggest descriptor */
 306#define EP0_BUFSIZE     256
 307#define DELAYED_STATUS  (EP0_BUFSIZE + 999)     /* An impossibly large value */
 308
 309/* Number of buffers we will use.  2 is enough for double-buffering */
 310#define FSG_NUM_BUFFERS 2
 311
 312/* Default size of buffer length. */
 313#define FSG_BUFLEN      ((u32)131072)
 314
 315/* Maximal number of LUNs supported in mass storage function */
 316#define FSG_MAX_LUNS    8
 317
 318enum fsg_buffer_state {
 319        BUF_STATE_EMPTY = 0,
 320        BUF_STATE_FULL,
 321        BUF_STATE_BUSY
 322};
 323
 324struct fsg_buffhd {
 325#ifdef FSG_BUFFHD_STATIC_BUFFER
 326        char                            buf[FSG_BUFLEN];
 327#else
 328        void                            *buf;
 329#endif
 330        enum fsg_buffer_state           state;
 331        struct fsg_buffhd               *next;
 332
 333        /*
 334         * The NetChip 2280 is faster, and handles some protocol faults
 335         * better, if we don't submit any short bulk-out read requests.
 336         * So we will record the intended request length here.
 337         */
 338        unsigned int                    bulk_out_intended_length;
 339
 340        struct usb_request              *inreq;
 341        int                             inreq_busy;
 342        struct usb_request              *outreq;
 343        int                             outreq_busy;
 344};
 345
 346enum fsg_state {
 347        /* This one isn't used anywhere */
 348        FSG_STATE_COMMAND_PHASE = -10,
 349        FSG_STATE_DATA_PHASE,
 350        FSG_STATE_STATUS_PHASE,
 351
 352        FSG_STATE_IDLE = 0,
 353        FSG_STATE_ABORT_BULK_OUT,
 354        FSG_STATE_RESET,
 355        FSG_STATE_INTERFACE_CHANGE,
 356        FSG_STATE_CONFIG_CHANGE,
 357        FSG_STATE_DISCONNECT,
 358        FSG_STATE_EXIT,
 359        FSG_STATE_TERMINATED
 360};
 361
 362enum data_direction {
 363        DATA_DIR_UNKNOWN = 0,
 364        DATA_DIR_FROM_HOST,
 365        DATA_DIR_TO_HOST,
 366        DATA_DIR_NONE
 367};
 368
 369/*-------------------------------------------------------------------------*/
 370
 371static inline u32 get_unaligned_be24(u8 *buf)
 372{
 373        return 0xffffff & (u32) get_unaligned_be32(buf - 1);
 374}
 375
 376/*-------------------------------------------------------------------------*/
 377
 378enum {
 379#ifndef FSG_NO_DEVICE_STRINGS
 380        FSG_STRING_MANUFACTURER = 1,
 381        FSG_STRING_PRODUCT,
 382        FSG_STRING_SERIAL,
 383        FSG_STRING_CONFIG,
 384#endif
 385        FSG_STRING_INTERFACE
 386};
 387
 388#ifndef FSG_NO_OTG
 389static struct usb_otg_descriptor
 390fsg_otg_desc = {
 391        .bLength =              sizeof fsg_otg_desc,
 392        .bDescriptorType =      USB_DT_OTG,
 393
 394        .bmAttributes =         USB_OTG_SRP,
 395};
 396#endif
 397
 398/* There is only one interface. */
 399
 400static struct usb_interface_descriptor
 401fsg_intf_desc = {
 402        .bLength =              sizeof fsg_intf_desc,
 403        .bDescriptorType =      USB_DT_INTERFACE,
 404
 405        .bNumEndpoints =        2,              /* Adjusted during fsg_bind() */
 406        .bInterfaceClass =      USB_CLASS_MASS_STORAGE,
 407        .bInterfaceSubClass =   USB_SC_SCSI,    /* Adjusted during fsg_bind() */
 408        .bInterfaceProtocol =   USB_PR_BULK,    /* Adjusted during fsg_bind() */
 409        .iInterface =           FSG_STRING_INTERFACE,
 410};
 411
 412/*
 413 * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
 414 * interrupt-in.
 415 */
 416
 417static struct usb_endpoint_descriptor
 418fsg_fs_bulk_in_desc = {
 419        .bLength =              USB_DT_ENDPOINT_SIZE,
 420        .bDescriptorType =      USB_DT_ENDPOINT,
 421
 422        .bEndpointAddress =     USB_DIR_IN,
 423        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 424        /* wMaxPacketSize set by autoconfiguration */
 425};
 426
 427static struct usb_endpoint_descriptor
 428fsg_fs_bulk_out_desc = {
 429        .bLength =              USB_DT_ENDPOINT_SIZE,
 430        .bDescriptorType =      USB_DT_ENDPOINT,
 431
 432        .bEndpointAddress =     USB_DIR_OUT,
 433        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 434        /* wMaxPacketSize set by autoconfiguration */
 435};
 436
 437#ifndef FSG_NO_INTR_EP
 438
 439static struct usb_endpoint_descriptor
 440fsg_fs_intr_in_desc = {
 441        .bLength =              USB_DT_ENDPOINT_SIZE,
 442        .bDescriptorType =      USB_DT_ENDPOINT,
 443
 444        .bEndpointAddress =     USB_DIR_IN,
 445        .bmAttributes =         USB_ENDPOINT_XFER_INT,
 446        .wMaxPacketSize =       cpu_to_le16(2),
 447        .bInterval =            32,     /* frames -> 32 ms */
 448};
 449
 450#ifndef FSG_NO_OTG
 451#  define FSG_FS_FUNCTION_PRE_EP_ENTRIES        2
 452#else
 453#  define FSG_FS_FUNCTION_PRE_EP_ENTRIES        1
 454#endif
 455
 456#endif
 457
 458static struct usb_descriptor_header *fsg_fs_function[] = {
 459#ifndef FSG_NO_OTG
 460        (struct usb_descriptor_header *) &fsg_otg_desc,
 461#endif
 462        (struct usb_descriptor_header *) &fsg_intf_desc,
 463        (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
 464        (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
 465#ifndef FSG_NO_INTR_EP
 466        (struct usb_descriptor_header *) &fsg_fs_intr_in_desc,
 467#endif
 468        NULL,
 469};
 470
 471/*
 472 * USB 2.0 devices need to expose both high speed and full speed
 473 * descriptors, unless they only run at full speed.
 474 *
 475 * That means alternate endpoint descriptors (bigger packets)
 476 * and a "device qualifier" ... plus more construction options
 477 * for the configuration descriptor.
 478 */
 479static struct usb_endpoint_descriptor
 480fsg_hs_bulk_in_desc = {
 481        .bLength =              USB_DT_ENDPOINT_SIZE,
 482        .bDescriptorType =      USB_DT_ENDPOINT,
 483
 484        /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 485        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 486        .wMaxPacketSize =       cpu_to_le16(512),
 487};
 488
 489static struct usb_endpoint_descriptor
 490fsg_hs_bulk_out_desc = {
 491        .bLength =              USB_DT_ENDPOINT_SIZE,
 492        .bDescriptorType =      USB_DT_ENDPOINT,
 493
 494        /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 495        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 496        .wMaxPacketSize =       cpu_to_le16(512),
 497        .bInterval =            1,      /* NAK every 1 uframe */
 498};
 499
 500#ifndef FSG_NO_INTR_EP
 501
 502static struct usb_endpoint_descriptor
 503fsg_hs_intr_in_desc = {
 504        .bLength =              USB_DT_ENDPOINT_SIZE,
 505        .bDescriptorType =      USB_DT_ENDPOINT,
 506
 507        /* bEndpointAddress copied from fs_intr_in_desc during fsg_bind() */
 508        .bmAttributes =         USB_ENDPOINT_XFER_INT,
 509        .wMaxPacketSize =       cpu_to_le16(2),
 510        .bInterval =            9,      /* 2**(9-1) = 256 uframes -> 32 ms */
 511};
 512
 513#ifndef FSG_NO_OTG
 514#  define FSG_HS_FUNCTION_PRE_EP_ENTRIES        2
 515#else
 516#  define FSG_HS_FUNCTION_PRE_EP_ENTRIES        1
 517#endif
 518
 519#endif
 520
 521static struct usb_descriptor_header *fsg_hs_function[] = {
 522#ifndef FSG_NO_OTG
 523        (struct usb_descriptor_header *) &fsg_otg_desc,
 524#endif
 525        (struct usb_descriptor_header *) &fsg_intf_desc,
 526        (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
 527        (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
 528#ifndef FSG_NO_INTR_EP
 529        (struct usb_descriptor_header *) &fsg_hs_intr_in_desc,
 530#endif
 531        NULL,
 532};
 533
 534/* Maxpacket and other transfer characteristics vary by speed. */
 535static struct usb_endpoint_descriptor *
 536fsg_ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
 537                struct usb_endpoint_descriptor *hs)
 538{
 539        if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
 540                return hs;
 541        return fs;
 542}
 543
 544/* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
 545static struct usb_string                fsg_strings[] = {
 546#ifndef FSG_NO_DEVICE_STRINGS
 547        {FSG_STRING_MANUFACTURER,       fsg_string_manufacturer},
 548        {FSG_STRING_PRODUCT,            fsg_string_product},
 549        {FSG_STRING_SERIAL,             fsg_string_serial},
 550        {FSG_STRING_CONFIG,             fsg_string_config},
 551#endif
 552        {FSG_STRING_INTERFACE,          fsg_string_interface},
 553        {}
 554};
 555
 556static struct usb_gadget_strings        fsg_stringtab = {
 557        .language       = 0x0409,               /* en-us */
 558        .strings        = fsg_strings,
 559};
 560
 561/*-------------------------------------------------------------------------*/
 562
 563/*
 564 * If the next two routines are called while the gadget is registered,
 565 * the caller must own fsg->filesem for writing.
 566 */
 567
 568static int fsg_lun_open(struct fsg_lun *curlun, unsigned int num_sectors,
 569                        const char *filename)
 570{
 571        int                             ro;
 572
 573        /* R/W if we can, R/O if we must */
 574        ro = curlun->initially_ro;
 575
 576        curlun->ro = ro;
 577        curlun->file_length = num_sectors << 9;
 578        curlun->num_sectors = num_sectors;
 579        debug("open backing file: %s\n", filename);
 580
 581        return 0;
 582}
 583
 584static void fsg_lun_close(struct fsg_lun *curlun)
 585{
 586}
 587
 588/*-------------------------------------------------------------------------*/
 589
 590/*
 591 * Sync the file data, don't bother with the metadata.
 592 * This code was copied from fs/buffer.c:sys_fdatasync().
 593 */
 594static int fsg_lun_fsync_sub(struct fsg_lun *curlun)
 595{
 596        return 0;
 597}
 598
 599static void store_cdrom_address(u8 *dest, int msf, u32 addr)
 600{
 601        if (msf) {
 602                /* Convert to Minutes-Seconds-Frames */
 603                addr >>= 2;             /* Convert to 2048-byte frames */
 604                addr += 2*75;           /* Lead-in occupies 2 seconds */
 605                dest[3] = addr % 75;    /* Frames */
 606                addr /= 75;
 607                dest[2] = addr % 60;    /* Seconds */
 608                addr /= 60;
 609                dest[1] = addr;         /* Minutes */
 610                dest[0] = 0;            /* Reserved */
 611        } else {
 612                /* Absolute sector */
 613                put_unaligned_be32(addr, dest);
 614        }
 615}
 616
 617/*-------------------------------------------------------------------------*/
 618