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  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23
  24 /*
  25  * This file requires the following identifiers used in USB strings to
  26  * be defined (each of type pointer to char):
  27  *  - fsg_string_manufacturer -- name of the manufacturer
  28  *  - fsg_string_product      -- name of the product
  29  *  - fsg_string_serial       -- product's serial
  30  *  - fsg_string_config       -- name of the configuration
  31  *  - fsg_string_interface    -- name of the interface
  32  * The first four are only needed when FSG_DESCRIPTORS_DEVICE_STRINGS
  33  * macro is defined prior to including this file.
  34  */
  35
  36 /*
  37  * When FSG_NO_INTR_EP is defined fsg_fs_intr_in_desc and
  38  * fsg_hs_intr_in_desc objects as well as
  39  * FSG_FS_FUNCTION_PRE_EP_ENTRIES and FSG_HS_FUNCTION_PRE_EP_ENTRIES
  40  * macros are not defined.
  41  *
  42  * When FSG_NO_DEVICE_STRINGS is defined FSG_STRING_MANUFACTURER,
  43  * FSG_STRING_PRODUCT, FSG_STRING_SERIAL and FSG_STRING_CONFIG are not
  44  * defined (as well as corresponding entries in string tables are
  45  * missing) and FSG_STRING_INTERFACE has value of zero.
  46  *
  47  * When FSG_NO_OTG is defined fsg_otg_desc won't be defined.
  48  */
  49
  50 /*
  51  * When FSG_BUFFHD_STATIC_BUFFER is defined when this file is included
  52  * the fsg_buffhd structure's buf field will be an array of FSG_BUFLEN
  53  * characters rather then a pointer to void.
  54  */
  55
  56
  57 #include <asm/unaligned.h>
  58
  59
  60 /* Thanks to NetChip Technologies for donating this product ID.
  61  *
  62  * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
  63  * Instead:  allocate your own, using normal USB-IF procedures. */
  64 #define FSG_VENDOR_ID   0x0525  /* NetChip */
  65 #define FSG_PRODUCT_ID  0xa4a5  /* Linux-USB File-backed Storage Gadget */
  66
  67
  68 /*-------------------------------------------------------------------------*/
  69
  70
  71 #ifndef DEBUG
  72 #undef VERBOSE_DEBUG
  73 #undef DUMP_MSGS
  74 #endif /* !DEBUG */
  75
  76 #ifdef VERBOSE_DEBUG
  77 #define VLDBG   LDBG
  78 #else
  79 #define VLDBG(lun, fmt, args...) do { } while (0)
  80 #endif /* VERBOSE_DEBUG */
  81
  82 #define LDBG(lun, fmt, args...)   dev_dbg (&(lun)->dev, fmt, ## args)
  83 #define LERROR(lun, fmt, args...) dev_err (&(lun)->dev, fmt, ## args)
  84 #define LWARN(lun, fmt, args...)  dev_warn(&(lun)->dev, fmt, ## args)
  85 #define LINFO(lun, fmt, args...)  dev_info(&(lun)->dev, fmt, ## args)
  86
  87 /* Keep those macros in sync with thos in
  88  * include/linux/ubs/composite.h or else GCC will complain.  If they
  89  * are identical (the same names of arguments, white spaces in the
  90  * same places) GCC will allow redefinition otherwise (even if some
  91  * white space is removed or added) warning will be issued.  No
  92  * checking if those symbols is defined is performed because warning
  93  * is desired when those macros were defined by someone else to mean
  94  * something else. */
  95 #define DBG(d, fmt, args...)     dev_dbg(&(d)->gadget->dev , fmt , ## args)
  96 #define VDBG(d, fmt, args...)    dev_vdbg(&(d)->gadget->dev , fmt , ## args)
  97 #define ERROR(d, fmt, args...)   dev_err(&(d)->gadget->dev , fmt , ## args)
  98 #define WARNING(d, fmt, args...) dev_warn(&(d)->gadget->dev , fmt , ## args)
  99 #define INFO(d, fmt, args...)    dev_info(&(d)->gadget->dev , fmt , ## args)
 100
 101
 102
 103 #ifdef DUMP_MSGS
 104
 105 #  define dump_msg(fsg, /* const char * */ label,                       \
 106                    /* const u8 * */ buf, /* unsigned */ length) do {    \
 107         if (length < 512) {                                             \
 108                 DBG(fsg, "%s, length %u:\n", label, length);            \
 109                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET,      \
 110                                16, 1, buf, length, 0);                  \
 111         }                                                               \
 112 } while (0)
 113
 114 #  define dump_cdb(fsg) do { } while (0)
 115
 116 #else
 117
 118 #  define dump_msg(fsg, /* const char * */ label, \
 119                    /* const u8 * */ buf, /* unsigned */ length) do { } while (0)
 120
 121 #  ifdef VERBOSE_DEBUG
 122
 123 #    define dump_cdb(fsg)                                               \
 124         print_hex_dump(KERN_DEBUG, "SCSI CDB: ", DUMP_PREFIX_NONE,      \
 125                        16, 1, (fsg)->cmnd, (fsg)->cmnd_size, 0)         \
 126
 127 #  else
 128
 129 #    define dump_cdb(fsg) do { } while (0)
 130
 131 #  endif /* VERBOSE_DEBUG */
 132
 133 #endif /* DUMP_MSGS */
 134
 135
 136
 137
 138
 139 /*-------------------------------------------------------------------------*/
 140
 141 /* SCSI device types */
 142 #define TYPE_DISK       0x00
 143 #define TYPE_CDROM      0x05
 144
 145 /* USB protocol value = the transport method */
 146 #define USB_PR_CBI      0x00            /* Control/Bulk/Interrupt */
 147 #define USB_PR_CB       0x01            /* Control/Bulk w/o interrupt */
 148 #define USB_PR_BULK     0x50            /* Bulk-only */
 149
 150 /* USB subclass value = the protocol encapsulation */
 151 #define USB_SC_RBC      0x01            /* Reduced Block Commands (flash) */
 152 #define USB_SC_8020     0x02            /* SFF-8020i, MMC-2, ATAPI (CD-ROM) */
 153 #define USB_SC_QIC      0x03            /* QIC-157 (tape) */
 154 #define USB_SC_UFI      0x04            /* UFI (floppy) */
 155 #define USB_SC_8070     0x05            /* SFF-8070i (removable) */
 156 #define USB_SC_SCSI     0x06            /* Transparent SCSI */
 157
 158 /* Bulk-only data structures */
 159
 160 /* Command Block Wrapper */
 161 struct fsg_bulk_cb_wrap {
 162         __le32  Signature;              /* Contains 'USBC' */
 163         u32     Tag;                    /* Unique per command id */
 164         __le32  DataTransferLength;     /* Size of the data */
 165         u8      Flags;                  /* Direction in bit 7 */
 166         u8      Lun;                    /* LUN (normally 0) */
 167         u8      Length;                 /* Of the CDB, <= MAX_COMMAND_SIZE */
 168         u8      CDB[16];                /* Command Data Block */
 169 };
 170
 171 #define USB_BULK_CB_WRAP_LEN    31
 172 #define USB_BULK_CB_SIG         0x43425355      /* Spells out USBC */
 173 #define USB_BULK_IN_FLAG        0x80
 174
 175 /* Command Status Wrapper */
 176 struct bulk_cs_wrap {
 177         __le32  Signature;              /* Should = 'USBS' */
 178         u32     Tag;                    /* Same as original command */
 179         __le32  Residue;                /* Amount not transferred */
 180         u8      Status;                 /* See below */
 181 };
 182
 183 #define USB_BULK_CS_WRAP_LEN    13
 184 #define USB_BULK_CS_SIG         0x53425355      /* Spells out 'USBS' */
 185 #define USB_STATUS_PASS         0
 186 #define USB_STATUS_FAIL         1
 187 #define USB_STATUS_PHASE_ERROR  2
 188
 189 /* Bulk-only class specific requests */
 190 #define USB_BULK_RESET_REQUEST          0xff
 191 #define USB_BULK_GET_MAX_LUN_REQUEST    0xfe
 192
 193
 194 /* CBI Interrupt data structure */
 195 struct interrupt_data {
 196         u8      bType;
 197         u8      bValue;
 198 };
 199
 200 #define CBI_INTERRUPT_DATA_LEN          2
 201
 202 /* CBI Accept Device-Specific Command request */
 203 #define USB_CBI_ADSC_REQUEST            0x00
 204
 205
 206 /* Length of a SCSI Command Data Block */
 207 #define MAX_COMMAND_SIZE        16
 208
 209 /* SCSI commands that we recognize */
 210 #define SC_FORMAT_UNIT                  0x04
 211 #define SC_INQUIRY                      0x12
 212 #define SC_MODE_SELECT_6                0x15
 213 #define SC_MODE_SELECT_10               0x55
 214 #define SC_MODE_SENSE_6                 0x1a
 215 #define SC_MODE_SENSE_10                0x5a
 216 #define SC_PREVENT_ALLOW_MEDIUM_REMOVAL 0x1e
 217 #define SC_READ_6                       0x08
 218 #define SC_READ_10                      0x28
 219 #define SC_READ_12                      0xa8
 220 #define SC_READ_CAPACITY                0x25
 221 #define SC_READ_FORMAT_CAPACITIES       0x23
 222 #define SC_READ_HEADER                  0x44
 223 #define SC_READ_TOC                     0x43
 224 #define SC_RELEASE                      0x17
 225 #define SC_REQUEST_SENSE                0x03
 226 #define SC_RESERVE                      0x16
 227 #define SC_SEND_DIAGNOSTIC              0x1d
 228 #define SC_START_STOP_UNIT              0x1b
 229 #define SC_SYNCHRONIZE_CACHE            0x35
 230 #define SC_TEST_UNIT_READY              0x00
 231 #define SC_VERIFY                       0x2f
 232 #define SC_WRITE_6                      0x0a
 233 #define SC_WRITE_10                     0x2a
 234 #define SC_WRITE_12                     0xaa
 235
 236 /* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
 237 #define SS_NO_SENSE                             0
 238 #define SS_COMMUNICATION_FAILURE                0x040800
 239 #define SS_INVALID_COMMAND                      0x052000
 240 #define SS_INVALID_FIELD_IN_CDB                 0x052400
 241 #define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE   0x052100
 242 #define SS_LOGICAL_UNIT_NOT_SUPPORTED           0x052500
 243 #define SS_MEDIUM_NOT_PRESENT                   0x023a00
 244 #define SS_MEDIUM_REMOVAL_PREVENTED             0x055302
 245 #define SS_NOT_READY_TO_READY_TRANSITION        0x062800
 246 #define SS_RESET_OCCURRED                       0x062900
 247 #define SS_SAVING_PARAMETERS_NOT_SUPPORTED      0x053900
 248 #define SS_UNRECOVERED_READ_ERROR               0x031100
 249 #define SS_WRITE_ERROR                          0x030c02
 250 #define SS_WRITE_PROTECTED                      0x072700
 251
 252 #define SK(x)           ((u8) ((x) >> 16))      /* Sense Key byte, etc. */
 253 #define ASC(x)          ((u8) ((x) >> 8))
 254 #define ASCQ(x)         ((u8) (x))
 255
 256
 257 /*-------------------------------------------------------------------------*/
 258
 259
 260 struct fsg_lun {
 261         struct file     *filp;
 262         loff_t          file_length;
 263         loff_t          num_sectors;
 264
 265         unsigned int    initially_ro:1;
 266         unsigned int    ro:1;
 267         unsigned int    removable:1;
 268         unsigned int    cdrom:1;
 269         unsigned int    prevent_medium_removal:1;
 270         unsigned int    registered:1;
 271         unsigned int    info_valid:1;
 272
 273         u32             sense_data;
 274         u32             sense_data_info;
 275         u32             unit_attention_data;
 276
 277         struct device   dev;
 278 };
 279
 280 #define fsg_lun_is_open(curlun) ((curlun)->filp != NULL)
 281
 282 static struct fsg_lun *fsg_lun_from_dev(struct device *dev)
 283 {
 284         return container_of(dev, struct fsg_lun, dev);
 285 }
 286
 287
 288 /* Big enough to hold our biggest descriptor */
 289 #define EP0_BUFSIZE     256
 290 #define DELAYED_STATUS  (EP0_BUFSIZE + 999)     /* An impossibly large value */
 291
 292 /* Number of buffers we will use.  2 is enough for double-buffering */
 293 #define FSG_NUM_BUFFERS 2
 294
 295 /* Default size of buffer length. */
 296 #define FSG_BUFLEN      ((u32)16384)
 297
 298 /* Maximal number of LUNs supported in mass storage function */
 299 #define FSG_MAX_LUNS    8
 300
 301 enum fsg_buffer_state {
 302         BUF_STATE_EMPTY = 0,
 303         BUF_STATE_FULL,
 304         BUF_STATE_BUSY
 305 };
 306
 307 struct fsg_buffhd {
 308 #ifdef FSG_BUFFHD_STATIC_BUFFER
 309         char                            buf[FSG_BUFLEN];
 310 #else
 311         void                            *buf;
 312 #endif
 313         enum fsg_buffer_state           state;
 314         struct fsg_buffhd               *next;
 315
 316         /* The NetChip 2280 is faster, and handles some protocol faults
 317          * better, if we don't submit any short bulk-out read requests.
 318          * So we will record the intended request length here. */
 319         unsigned int                    bulk_out_intended_length;
 320
 321         struct usb_request              *inreq;
 322         int                             inreq_busy;
 323         struct usb_request              *outreq;
 324         int                             outreq_busy;
 325 };
 326
 327 enum fsg_state {
 328         /* This one isn't used anywhere */
 329         FSG_STATE_COMMAND_PHASE = -10,
 330         FSG_STATE_DATA_PHASE,
 331         FSG_STATE_STATUS_PHASE,
 332
 333         FSG_STATE_IDLE = 0,
 334         FSG_STATE_ABORT_BULK_OUT,
 335         FSG_STATE_RESET,
 336         FSG_STATE_INTERFACE_CHANGE,
 337         FSG_STATE_CONFIG_CHANGE,
 338         FSG_STATE_DISCONNECT,
 339         FSG_STATE_EXIT,
 340         FSG_STATE_TERMINATED
 341 };
 342
 343 enum data_direction {
 344         DATA_DIR_UNKNOWN = 0,
 345         DATA_DIR_FROM_HOST,
 346         DATA_DIR_TO_HOST,
 347         DATA_DIR_NONE
 348 };
 349
 350
 351 /*-------------------------------------------------------------------------*/
 352
 353
 354 static inline u32 get_unaligned_be24(u8 *buf)
 355 {
 356         return 0xffffff & (u32) get_unaligned_be32(buf - 1);
 357 }
 358
 359
 360 /*-------------------------------------------------------------------------*/
 361
 362
 363 enum {
 364 #ifndef FSG_NO_DEVICE_STRINGS
 365         FSG_STRING_MANUFACTURER = 1,
 366         FSG_STRING_PRODUCT,
 367         FSG_STRING_SERIAL,
 368         FSG_STRING_CONFIG,
 369 #endif
 370         FSG_STRING_INTERFACE
 371 };
 372
 373
 374 #ifndef FSG_NO_OTG
 375 static struct usb_otg_descriptor
 376 fsg_otg_desc = {
 377         .bLength =              sizeof fsg_otg_desc,
 378         .bDescriptorType =      USB_DT_OTG,
 379
 380         .bmAttributes =         USB_OTG_SRP,
 381 };
 382 #endif
 383
 384 /* There is only one interface. */
 385
 386 static struct usb_interface_descriptor
 387 fsg_intf_desc = {
 388         .bLength =              sizeof fsg_intf_desc,
 389         .bDescriptorType =      USB_DT_INTERFACE,
 390
 391         .bNumEndpoints =        2,              /* Adjusted during fsg_bind() */
 392         .bInterfaceClass =      USB_CLASS_MASS_STORAGE,
 393         .bInterfaceSubClass =   USB_SC_SCSI,    /* Adjusted during fsg_bind() */
 394         .bInterfaceProtocol =   USB_PR_BULK,    /* Adjusted during fsg_bind() */
 395         .iInterface =           FSG_STRING_INTERFACE,
 396 };
 397
 398 /* Three full-speed endpoint descriptors: bulk-in, bulk-out,
 399  * and interrupt-in. */
 400
 401 static struct usb_endpoint_descriptor
 402 fsg_fs_bulk_in_desc = {
 403         .bLength =              USB_DT_ENDPOINT_SIZE,
 404         .bDescriptorType =      USB_DT_ENDPOINT,
 405
 406         .bEndpointAddress =     USB_DIR_IN,
 407         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 408         /* wMaxPacketSize set by autoconfiguration */
 409 };
 410
 411 static struct usb_endpoint_descriptor
 412 fsg_fs_bulk_out_desc = {
 413         .bLength =              USB_DT_ENDPOINT_SIZE,
 414         .bDescriptorType =      USB_DT_ENDPOINT,
 415
 416         .bEndpointAddress =     USB_DIR_OUT,
 417         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 418         /* wMaxPacketSize set by autoconfiguration */
 419 };
 420
 421 #ifndef FSG_NO_INTR_EP
 422
 423 static struct usb_endpoint_descriptor
 424 fsg_fs_intr_in_desc = {
 425         .bLength =              USB_DT_ENDPOINT_SIZE,
 426         .bDescriptorType =      USB_DT_ENDPOINT,
 427
 428         .bEndpointAddress =     USB_DIR_IN,
 429         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 430         .wMaxPacketSize =       cpu_to_le16(2),
 431         .bInterval =            32,     /* frames -> 32 ms */
 432 };
 433
 434 #ifndef FSG_NO_OTG
 435 #  define FSG_FS_FUNCTION_PRE_EP_ENTRIES        2
 436 #else
 437 #  define FSG_FS_FUNCTION_PRE_EP_ENTRIES        1
 438 #endif
 439
 440 #endif
 441
 442 static struct usb_descriptor_header *fsg_fs_function[] = {
 443 #ifndef FSG_NO_OTG
 444         (struct usb_descriptor_header *) &fsg_otg_desc,
 445 #endif
 446         (struct usb_descriptor_header *) &fsg_intf_desc,
 447         (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
 448         (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
 449 #ifndef FSG_NO_INTR_EP
 450         (struct usb_descriptor_header *) &fsg_fs_intr_in_desc,
 451 #endif
 452         NULL,
 453 };
 454
 455
 456 /*
 457  * USB 2.0 devices need to expose both high speed and full speed
 458  * descriptors, unless they only run at full speed.
 459  *
 460  * That means alternate endpoint descriptors (bigger packets)
 461  * and a "device qualifier" ... plus more construction options
 462  * for the config descriptor.
 463  */
 464 static struct usb_endpoint_descriptor
 465 fsg_hs_bulk_in_desc = {
 466         .bLength =              USB_DT_ENDPOINT_SIZE,
 467         .bDescriptorType =      USB_DT_ENDPOINT,
 468
 469         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 470         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 471         .wMaxPacketSize =       cpu_to_le16(512),
 472 };
 473
 474 static struct usb_endpoint_descriptor
 475 fsg_hs_bulk_out_desc = {
 476         .bLength =              USB_DT_ENDPOINT_SIZE,
 477         .bDescriptorType =      USB_DT_ENDPOINT,
 478
 479         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 480         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 481         .wMaxPacketSize =       cpu_to_le16(512),
 482         .bInterval =            1,      /* NAK every 1 uframe */
 483 };
 484
 485 #ifndef FSG_NO_INTR_EP
 486
 487 static struct usb_endpoint_descriptor
 488 fsg_hs_intr_in_desc = {
 489         .bLength =              USB_DT_ENDPOINT_SIZE,
 490         .bDescriptorType =      USB_DT_ENDPOINT,
 491
 492         /* bEndpointAddress copied from fs_intr_in_desc during fsg_bind() */
 493         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 494         .wMaxPacketSize =       cpu_to_le16(2),
 495         .bInterval =            9,      /* 2**(9-1) = 256 uframes -> 32 ms */
 496 };
 497
 498 #ifndef FSG_NO_OTG
 499 #  define FSG_HS_FUNCTION_PRE_EP_ENTRIES        2
 500 #else
 501 #  define FSG_HS_FUNCTION_PRE_EP_ENTRIES        1
 502 #endif
 503
 504 #endif
 505
 506 static struct usb_descriptor_header *fsg_hs_function[] = {
 507 #ifndef FSG_NO_OTG
 508         (struct usb_descriptor_header *) &fsg_otg_desc,
 509 #endif
 510         (struct usb_descriptor_header *) &fsg_intf_desc,
 511         (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
 512         (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
 513 #ifndef FSG_NO_INTR_EP
 514         (struct usb_descriptor_header *) &fsg_hs_intr_in_desc,
 515 #endif
 516         NULL,
 517 };
 518
 519 /* Maxpacket and other transfer characteristics vary by speed. */
 520 static struct usb_endpoint_descriptor *
 521 fsg_ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
 522                 struct usb_endpoint_descriptor *hs)
 523 {
 524         if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
 525                 return hs;
 526         return fs;
 527 }
 528
 529
 530 /* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
 531 static struct usb_string                fsg_strings[] = {
 532 #ifndef FSG_NO_DEVICE_STRINGS
 533         {FSG_STRING_MANUFACTURER,       fsg_string_manufacturer},
 534         {FSG_STRING_PRODUCT,            fsg_string_product},
 535         {FSG_STRING_SERIAL,             fsg_string_serial},
 536         {FSG_STRING_CONFIG,             fsg_string_config},
 537 #endif
 538         {FSG_STRING_INTERFACE,          fsg_string_interface},
 539         {}
 540 };
 541
 542 static struct usb_gadget_strings        fsg_stringtab = {
 543         .language       = 0x0409,               /* en-us */
 544         .strings        = fsg_strings,
 545 };
 546
 547
 548  /*-------------------------------------------------------------------------*/
 549
 550 /* If the next two routines are called while the gadget is registered,
 551  * the caller must own fsg->filesem for writing. */
 552
 553 static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 554 {
 555         int                             ro;
 556         struct file                     *filp = NULL;
 557         int                             rc = -EINVAL;
 558         struct inode                    *inode = NULL;
 559         loff_t                          size;
 560         loff_t                          num_sectors;
 561         loff_t                          min_sectors;
 562
 563         /* R/W if we can, R/O if we must */
 564         ro = curlun->initially_ro;
 565         if (!ro) {
 566                 filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
 567                 if (-EROFS == PTR_ERR(filp))
 568                         ro = 1;
 569         }
 570         if (ro)
 571                 filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
 572         if (IS_ERR(filp)) {
 573                 LINFO(curlun, "unable to open backing file: %s\n", filename);
 574                 return PTR_ERR(filp);
 575         }
 576
 577         if (!(filp->f_mode & FMODE_WRITE))
 578                 ro = 1;
 579
 580         if (filp->f_path.dentry)
 581                 inode = filp->f_path.dentry->d_inode;
 582         if (inode && S_ISBLK(inode->i_mode)) {
 583                 if (bdev_read_only(inode->i_bdev))
 584                         ro = 1;
 585         } else if (!inode || !S_ISREG(inode->i_mode)) {
 586                 LINFO(curlun, "invalid file type: %s\n", filename);
 587                 goto out;
 588         }
 589
 590         /* If we can't read the file, it's no good.
 591          * If we can't write the file, use it read-only. */
 592         if (!filp->f_op || !(filp->f_op->read || filp->f_op->aio_read)) {
 593                 LINFO(curlun, "file not readable: %s\n", filename);
 594                 goto out;
 595         }
 596         if (!(filp->f_op->write || filp->f_op->aio_write))
 597                 ro = 1;
 598
 599         size = i_size_read(inode->i_mapping->host);
 600         if (size < 0) {
 601                 LINFO(curlun, "unable to find file size: %s\n", filename);
 602                 rc = (int) size;
 603                 goto out;
 604         }
 605         num_sectors = size >> 9;        /* File size in 512-byte blocks */
 606         min_sectors = 1;
 607         if (curlun->cdrom) {
 608                 num_sectors &= ~3;      /* Reduce to a multiple of 2048 */
 609                 min_sectors = 300*4;    /* Smallest track is 300 frames */
 610                 if (num_sectors >= 256*60*75*4) {
 611                         num_sectors = (256*60*75 - 1) * 4;
 612                         LINFO(curlun, "file too big: %s\n", filename);
 613                         LINFO(curlun, "using only first %d blocks\n",
 614                                         (int) num_sectors);
 615                 }
 616         }
 617         if (num_sectors < min_sectors) {
 618                 LINFO(curlun, "file too small: %s\n", filename);
 619                 rc = -ETOOSMALL;
 620                 goto out;
 621         }
 622
 623         get_file(filp);
 624         curlun->ro = ro;
 625         curlun->filp = filp;
 626         curlun->file_length = size;
 627         curlun->num_sectors = num_sectors;
 628         LDBG(curlun, "open backing file: %s\n", filename);
 629         rc = 0;
 630
 631 out:
 632         filp_close(filp, current->files);
 633         return rc;
 634 }
 635
 636
 637 static void fsg_lun_close(struct fsg_lun *curlun)
 638 {
 639         if (curlun->filp) {
 640                 LDBG(curlun, "close backing file\n");
 641                 fput(curlun->filp);
 642                 curlun->filp = NULL;
 643         }
 644 }
 645
 646
 647 /*-------------------------------------------------------------------------*/
 648
 649 /* Sync the file data, don't bother with the metadata.
 650  * This code was copied from fs/buffer.c:sys_fdatasync(). */
 651 static int fsg_lun_fsync_sub(struct fsg_lun *curlun)
 652 {
 653         struct file     *filp = curlun->filp;
 654
 655         if (curlun->ro || !filp)
 656                 return 0;
 657         return vfs_fsync(filp, filp->f_path.dentry, 1);
 658 }
 659
 660 static void store_cdrom_address(u8 *dest, int msf, u32 addr)
 661 {
 662         if (msf) {
 663                 /* Convert to Minutes-Seconds-Frames */
 664                 addr >>= 2;             /* Convert to 2048-byte frames */
 665                 addr += 2*75;           /* Lead-in occupies 2 seconds */
 666                 dest[3] = addr % 75;    /* Frames */
 667                 addr /= 75;
 668                 dest[2] = addr % 60;    /* Seconds */
 669                 addr /= 60;
 670                 dest[1] = addr;         /* Minutes */
 671                 dest[0] = 0;            /* Reserved */
 672         } else {
 673                 /* Absolute sector */
 674                 put_unaligned_be32(addr, dest);
 675         }
 676 }
 677
 678
 679 /*-------------------------------------------------------------------------*/
 680
 681
 682 static ssize_t fsg_show_ro(struct device *dev, struct device_attribute *attr,
 683                            char *buf)
 684 {
 685         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 686
 687         return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
 688                                   ? curlun->ro
 689                                   : curlun->initially_ro);
 690 }
 691
 692 static ssize_t fsg_show_file(struct device *dev, struct device_attribute *attr,
 693                              char *buf)
 694 {
 695         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 696         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 697         char            *p;
 698         ssize_t         rc;
 699
 700         down_read(filesem);
 701         if (fsg_lun_is_open(curlun)) {  /* Get the complete pathname */
 702                 p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1);
 703                 if (IS_ERR(p))
 704                         rc = PTR_ERR(p);
 705                 else {
 706                         rc = strlen(p);
 707                         memmove(buf, p, rc);
 708                         buf[rc] = '\n';         /* Add a newline */
 709                         buf[++rc] = 0;
 710                 }
 711         } else {                                /* No file, return 0 bytes */
 712                 *buf = 0;
 713                 rc = 0;
 714         }
 715         up_read(filesem);
 716         return rc;
 717 }
 718
 719
 720 static ssize_t fsg_store_ro(struct device *dev, struct device_attribute *attr,
 721                             const char *buf, size_t count)
 722 {
 723         ssize_t         rc = count;
 724         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 725         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 726         int             i;
 727
 728         if (sscanf(buf, "%d", &i) != 1)
 729                 return -EINVAL;
 730
 731         /* Allow the write-enable status to change only while the backing file
 732          * is closed. */
 733         down_read(filesem);
 734         if (fsg_lun_is_open(curlun)) {
 735                 LDBG(curlun, "read-only status change prevented\n");
 736                 rc = -EBUSY;
 737         } else {
 738                 curlun->ro = !!i;
 739                 curlun->initially_ro = !!i;
 740                 LDBG(curlun, "read-only status set to %d\n", curlun->ro);
 741         }
 742         up_read(filesem);
 743         return rc;
 744 }
 745
 746 static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr,
 747                               const char *buf, size_t count)
 748 {
 749         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 750         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 751         int             rc = 0;
 752
 753         if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
 754                 LDBG(curlun, "eject attempt prevented\n");
 755                 return -EBUSY;                          /* "Door is locked" */
 756         }
 757
 758         /* Remove a trailing newline */
 759         if (count > 0 && buf[count-1] == '\n')
 760                 ((char *) buf)[count-1] = 0;            /* Ugh! */
 761
 762         /* Eject current medium */
 763         down_write(filesem);
 764         if (fsg_lun_is_open(curlun)) {
 765                 fsg_lun_close(curlun);
 766                 curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
 767         }
 768
 769         /* Load new medium */
 770         if (count > 0 && buf[0]) {
 771                 rc = fsg_lun_open(curlun, buf);
 772                 if (rc == 0)
 773                         curlun->unit_attention_data =
 774                                         SS_NOT_READY_TO_READY_TRANSITION;
 775         }
 776         up_write(filesem);
 777         return (rc < 0 ? rc : count);
 778 }