SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 #include <asm/unaligned.h>
  38
  39
  40 /* Thanks to NetChip Technologies for donating this product ID.
  41  *
  42  * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
  43  * Instead:  allocate your own, using normal USB-IF procedures. */
  44 #define FSG_VENDOR_ID   0x0525  // NetChip
  45 #define FSG_PRODUCT_ID  0xa4a5  // Linux-USB File-backed Storage Gadget
  46
  47
  48 /*-------------------------------------------------------------------------*/
  49
  50
  51 #ifndef DEBUG
  52 #undef VERBOSE_DEBUG
  53 #undef DUMP_MSGS
  54 #endif /* !DEBUG */
  55
  56 #ifdef VERBOSE_DEBUG
  57 #define VLDBG   LDBG
  58 #else
  59 #define VLDBG(lun, fmt, args...) do { } while (0)
  60 #endif /* VERBOSE_DEBUG */
  61
  62 #define LDBG(lun, fmt, args...)   dev_dbg (&(lun)->dev, fmt, ## args)
  63 #define LERROR(lun, fmt, args...) dev_err (&(lun)->dev, fmt, ## args)
  64 #define LWARN(lun, fmt, args...)  dev_warn(&(lun)->dev, fmt, ## args)
  65 #define LINFO(lun, fmt, args...)  dev_info(&(lun)->dev, fmt, ## args)
  66
  67 #define DBG(d, fmt, args...)      dev_dbg (&(d)->gadget->dev, fmt, ## args)
  68 #define VDBG(d, fmt, args...)     dev_vdbg(&(d)->gadget->dev, fmt, ## args)
  69 #define ERROR(d, fmt, args...)    dev_err (&(d)->gadget->dev, fmt, ## args)
  70 #define WARNING(d, fmt, args...)  dev_warn(&(d)->gadget->dev, fmt, ## args)
  71 #define INFO(d, fmt, args...)     dev_info(&(d)->gadget->dev, fmt, ## args)
  72
  73
  74
  75 #ifdef DUMP_MSGS
  76
  77 #  define dump_msg(fsg, /* const char * */ label,                       \
  78                  /* const u8 * */ buf, /* unsigned */ length) do {      \
  79         if (length < 512) {                                             \
  80                 DBG(fsg, "%s, length %u:\n", label, length);            \
  81                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET,      \
  82                                16, 1, buf, length, 0);                  \
  83         }                                                               \
  84 } while (0)
  85
  86 #  define dump_cdb(fsg) do { } while (0)
  87
  88 #else
  89
  90 #  define dump_msg(fsg, /* const char * */ label, \
  91                  /* const u8 * */ buf, /* unsigned */ length) do { } while (0)
  92
  93 #  ifdef VERBOSE_DEBUG
  94
  95 #define dump_cdb(fsg)                                                   \
  96         print_hex_dump(KERN_DEBUG, "SCSI CDB: ", DUMP_PREFIX_NONE,      \
  97                        16, 1, (fsg)->cmnd, (fsg)->cmnd_size, 0)         \
  98
  99 #  else
 100
 101 #    define dump_cdb(fsg) do { } while (0)
 102
 103 #  endif /* VERBOSE_DEBUG */
 104
 105 #endif /* DUMP_MSGS */
 106
 107
 108
 109
 110
 111 /*-------------------------------------------------------------------------*/
 112
 113 /* SCSI device types */
 114 #define TYPE_DISK       0x00
 115 #define TYPE_CDROM      0x05
 116
 117 /* USB protocol value = the transport method */
 118 #define USB_PR_CBI      0x00            // Control/Bulk/Interrupt
 119 #define USB_PR_CB       0x01            // Control/Bulk w/o interrupt
 120 #define USB_PR_BULK     0x50            // Bulk-only
 121
 122 /* USB subclass value = the protocol encapsulation */
 123 #define USB_SC_RBC      0x01            // Reduced Block Commands (flash)
 124 #define USB_SC_8020     0x02            // SFF-8020i, MMC-2, ATAPI (CD-ROM)
 125 #define USB_SC_QIC      0x03            // QIC-157 (tape)
 126 #define USB_SC_UFI      0x04            // UFI (floppy)
 127 #define USB_SC_8070     0x05            // SFF-8070i (removable)
 128 #define USB_SC_SCSI     0x06            // Transparent SCSI
 129
 130 /* Bulk-only data structures */
 131
 132 /* Command Block Wrapper */
 133 struct fsg_bulk_cb_wrap {
 134         __le32  Signature;              // Contains 'USBC'
 135         u32     Tag;                    // Unique per command id
 136         __le32  DataTransferLength;     // Size of the data
 137         u8      Flags;                  // Direction in bit 7
 138         u8      Lun;                    // LUN (normally 0)
 139         u8      Length;                 // Of the CDB, <= MAX_COMMAND_SIZE
 140         u8      CDB[16];                // Command Data Block
 141 };
 142
 143 #define USB_BULK_CB_WRAP_LEN    31
 144 #define USB_BULK_CB_SIG         0x43425355      // Spells out USBC
 145 #define USB_BULK_IN_FLAG        0x80
 146
 147 /* Command Status Wrapper */
 148 struct bulk_cs_wrap {
 149         __le32  Signature;              // Should = 'USBS'
 150         u32     Tag;                    // Same as original command
 151         __le32  Residue;                // Amount not transferred
 152         u8      Status;                 // See below
 153 };
 154
 155 #define USB_BULK_CS_WRAP_LEN    13
 156 #define USB_BULK_CS_SIG         0x53425355      // Spells out 'USBS'
 157 #define USB_STATUS_PASS         0
 158 #define USB_STATUS_FAIL         1
 159 #define USB_STATUS_PHASE_ERROR  2
 160
 161 /* Bulk-only class specific requests */
 162 #define USB_BULK_RESET_REQUEST          0xff
 163 #define USB_BULK_GET_MAX_LUN_REQUEST    0xfe
 164
 165
 166 /* CBI Interrupt data structure */
 167 struct interrupt_data {
 168         u8      bType;
 169         u8      bValue;
 170 };
 171
 172 #define CBI_INTERRUPT_DATA_LEN          2
 173
 174 /* CBI Accept Device-Specific Command request */
 175 #define USB_CBI_ADSC_REQUEST            0x00
 176
 177
 178 #define MAX_COMMAND_SIZE        16      // Length of a SCSI Command Data Block
 179
 180 /* SCSI commands that we recognize */
 181 #define SC_FORMAT_UNIT                  0x04
 182 #define SC_INQUIRY                      0x12
 183 #define SC_MODE_SELECT_6                0x15
 184 #define SC_MODE_SELECT_10               0x55
 185 #define SC_MODE_SENSE_6                 0x1a
 186 #define SC_MODE_SENSE_10                0x5a
 187 #define SC_PREVENT_ALLOW_MEDIUM_REMOVAL 0x1e
 188 #define SC_READ_6                       0x08
 189 #define SC_READ_10                      0x28
 190 #define SC_READ_12                      0xa8
 191 #define SC_READ_CAPACITY                0x25
 192 #define SC_READ_FORMAT_CAPACITIES       0x23
 193 #define SC_READ_HEADER                  0x44
 194 #define SC_READ_TOC                     0x43
 195 #define SC_RELEASE                      0x17
 196 #define SC_REQUEST_SENSE                0x03
 197 #define SC_RESERVE                      0x16
 198 #define SC_SEND_DIAGNOSTIC              0x1d
 199 #define SC_START_STOP_UNIT              0x1b
 200 #define SC_SYNCHRONIZE_CACHE            0x35
 201 #define SC_TEST_UNIT_READY              0x00
 202 #define SC_VERIFY                       0x2f
 203 #define SC_WRITE_6                      0x0a
 204 #define SC_WRITE_10                     0x2a
 205 #define SC_WRITE_12                     0xaa
 206
 207 /* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
 208 #define SS_NO_SENSE                             0
 209 #define SS_COMMUNICATION_FAILURE                0x040800
 210 #define SS_INVALID_COMMAND                      0x052000
 211 #define SS_INVALID_FIELD_IN_CDB                 0x052400
 212 #define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE   0x052100
 213 #define SS_LOGICAL_UNIT_NOT_SUPPORTED           0x052500
 214 #define SS_MEDIUM_NOT_PRESENT                   0x023a00
 215 #define SS_MEDIUM_REMOVAL_PREVENTED             0x055302
 216 #define SS_NOT_READY_TO_READY_TRANSITION        0x062800
 217 #define SS_RESET_OCCURRED                       0x062900
 218 #define SS_SAVING_PARAMETERS_NOT_SUPPORTED      0x053900
 219 #define SS_UNRECOVERED_READ_ERROR               0x031100
 220 #define SS_WRITE_ERROR                          0x030c02
 221 #define SS_WRITE_PROTECTED                      0x072700
 222
 223 #define SK(x)           ((u8) ((x) >> 16))      // Sense Key byte, etc.
 224 #define ASC(x)          ((u8) ((x) >> 8))
 225 #define ASCQ(x)         ((u8) (x))
 226
 227
 228 /*-------------------------------------------------------------------------*/
 229
 230
 231 struct fsg_lun {
 232         struct file     *filp;
 233         loff_t          file_length;
 234         loff_t          num_sectors;
 235
 236         unsigned int    initially_ro : 1;
 237         unsigned int    ro : 1;
 238         unsigned int    removable : 1;
 239         unsigned int    cdrom : 1;
 240         unsigned int    prevent_medium_removal : 1;
 241         unsigned int    registered : 1;
 242         unsigned int    info_valid : 1;
 243
 244         u32             sense_data;
 245         u32             sense_data_info;
 246         u32             unit_attention_data;
 247
 248         struct device   dev;
 249 };
 250
 251 #define fsg_lun_is_open(curlun) ((curlun)->filp != NULL)
 252
 253 static struct fsg_lun *fsg_lun_from_dev(struct device *dev)
 254 {
 255         return container_of(dev, struct fsg_lun, dev);
 256 }
 257
 258
 259 /* Big enough to hold our biggest descriptor */
 260 #define EP0_BUFSIZE     256
 261 #define DELAYED_STATUS  (EP0_BUFSIZE + 999)     // An impossibly large value
 262
 263 /* Number of buffers we will use.  2 is enough for double-buffering */
 264 #define FSG_NUM_BUFFERS 2
 265
 266 /* Default size of buffer length. */
 267 #define FSG_BUFLEN      ((u32)16384)
 268
 269 /* Maximal number of LUNs supported in mass storage function */
 270 #define FSG_MAX_LUNS    8
 271
 272 enum fsg_buffer_state {
 273         BUF_STATE_EMPTY = 0,
 274         BUF_STATE_FULL,
 275         BUF_STATE_BUSY
 276 };
 277
 278 struct fsg_buffhd {
 279         void                            *buf;
 280         enum fsg_buffer_state           state;
 281         struct fsg_buffhd               *next;
 282
 283         /* The NetChip 2280 is faster, and handles some protocol faults
 284          * better, if we don't submit any short bulk-out read requests.
 285          * So we will record the intended request length here. */
 286         unsigned int                    bulk_out_intended_length;
 287
 288         struct usb_request              *inreq;
 289         int                             inreq_busy;
 290         struct usb_request              *outreq;
 291         int                             outreq_busy;
 292 };
 293
 294 enum fsg_state {
 295         FSG_STATE_COMMAND_PHASE = -10,          // This one isn't used anywhere
 296         FSG_STATE_DATA_PHASE,
 297         FSG_STATE_STATUS_PHASE,
 298
 299         FSG_STATE_IDLE = 0,
 300         FSG_STATE_ABORT_BULK_OUT,
 301         FSG_STATE_RESET,
 302         FSG_STATE_INTERFACE_CHANGE,
 303         FSG_STATE_CONFIG_CHANGE,
 304         FSG_STATE_DISCONNECT,
 305         FSG_STATE_EXIT,
 306         FSG_STATE_TERMINATED
 307 };
 308
 309 enum data_direction {
 310         DATA_DIR_UNKNOWN = 0,
 311         DATA_DIR_FROM_HOST,
 312         DATA_DIR_TO_HOST,
 313         DATA_DIR_NONE
 314 };
 315
 316
 317 /*-------------------------------------------------------------------------*/
 318
 319
 320 static inline u32 get_unaligned_be24(u8 *buf)
 321 {
 322         return 0xffffff & (u32) get_unaligned_be32(buf - 1);
 323 }
 324
 325
 326 /*-------------------------------------------------------------------------*/
 327
 328
 329 enum {
 330         FSG_STRING_MANUFACTURER = 1,
 331         FSG_STRING_PRODUCT,
 332         FSG_STRING_SERIAL,
 333         FSG_STRING_CONFIG,
 334         FSG_STRING_INTERFACE
 335 };
 336
 337
 338 static struct usb_otg_descriptor
 339 fsg_otg_desc = {
 340         .bLength =              sizeof fsg_otg_desc,
 341         .bDescriptorType =      USB_DT_OTG,
 342
 343         .bmAttributes =         USB_OTG_SRP,
 344 };
 345
 346 /* There is only one interface. */
 347
 348 static struct usb_interface_descriptor
 349 fsg_intf_desc = {
 350         .bLength =              sizeof fsg_intf_desc,
 351         .bDescriptorType =      USB_DT_INTERFACE,
 352
 353         .bNumEndpoints =        2,              // Adjusted during fsg_bind()
 354         .bInterfaceClass =      USB_CLASS_MASS_STORAGE,
 355         .bInterfaceSubClass =   USB_SC_SCSI,    // Adjusted during fsg_bind()
 356         .bInterfaceProtocol =   USB_PR_BULK,    // Adjusted during fsg_bind()
 357         .iInterface =           FSG_STRING_INTERFACE,
 358 };
 359
 360 /* Three full-speed endpoint descriptors: bulk-in, bulk-out,
 361  * and interrupt-in. */
 362
 363 static struct usb_endpoint_descriptor
 364 fsg_fs_bulk_in_desc = {
 365         .bLength =              USB_DT_ENDPOINT_SIZE,
 366         .bDescriptorType =      USB_DT_ENDPOINT,
 367
 368         .bEndpointAddress =     USB_DIR_IN,
 369         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 370         /* wMaxPacketSize set by autoconfiguration */
 371 };
 372
 373 static struct usb_endpoint_descriptor
 374 fsg_fs_bulk_out_desc = {
 375         .bLength =              USB_DT_ENDPOINT_SIZE,
 376         .bDescriptorType =      USB_DT_ENDPOINT,
 377
 378         .bEndpointAddress =     USB_DIR_OUT,
 379         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 380         /* wMaxPacketSize set by autoconfiguration */
 381 };
 382
 383 static struct usb_endpoint_descriptor
 384 fsg_fs_intr_in_desc = {
 385         .bLength =              USB_DT_ENDPOINT_SIZE,
 386         .bDescriptorType =      USB_DT_ENDPOINT,
 387
 388         .bEndpointAddress =     USB_DIR_IN,
 389         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 390         .wMaxPacketSize =       cpu_to_le16(2),
 391         .bInterval =            32,     // frames -> 32 ms
 392 };
 393
 394 static const struct usb_descriptor_header *fsg_fs_function[] = {
 395         (struct usb_descriptor_header *) &fsg_otg_desc,
 396         (struct usb_descriptor_header *) &fsg_intf_desc,
 397         (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
 398         (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
 399         (struct usb_descriptor_header *) &fsg_fs_intr_in_desc,
 400         NULL,
 401 };
 402 #define FSG_FS_FUNCTION_PRE_EP_ENTRIES  2
 403
 404
 405 /*
 406  * USB 2.0 devices need to expose both high speed and full speed
 407  * descriptors, unless they only run at full speed.
 408  *
 409  * That means alternate endpoint descriptors (bigger packets)
 410  * and a "device qualifier" ... plus more construction options
 411  * for the config descriptor.
 412  */
 413 static struct usb_endpoint_descriptor
 414 fsg_hs_bulk_in_desc = {
 415         .bLength =              USB_DT_ENDPOINT_SIZE,
 416         .bDescriptorType =      USB_DT_ENDPOINT,
 417
 418         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 419         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 420         .wMaxPacketSize =       cpu_to_le16(512),
 421 };
 422
 423 static struct usb_endpoint_descriptor
 424 fsg_hs_bulk_out_desc = {
 425         .bLength =              USB_DT_ENDPOINT_SIZE,
 426         .bDescriptorType =      USB_DT_ENDPOINT,
 427
 428         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 429         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 430         .wMaxPacketSize =       cpu_to_le16(512),
 431         .bInterval =            1,      // NAK every 1 uframe
 432 };
 433
 434 static struct usb_endpoint_descriptor
 435 fsg_hs_intr_in_desc = {
 436         .bLength =              USB_DT_ENDPOINT_SIZE,
 437         .bDescriptorType =      USB_DT_ENDPOINT,
 438
 439         /* bEndpointAddress copied from fs_intr_in_desc during fsg_bind() */
 440         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 441         .wMaxPacketSize =       cpu_to_le16(2),
 442         .bInterval =            9,      // 2**(9-1) = 256 uframes -> 32 ms
 443 };
 444
 445 static const struct usb_descriptor_header *fsg_hs_function[] = {
 446         (struct usb_descriptor_header *) &fsg_otg_desc,
 447         (struct usb_descriptor_header *) &fsg_intf_desc,
 448         (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
 449         (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
 450         (struct usb_descriptor_header *) &fsg_hs_intr_in_desc,
 451         NULL,
 452 };
 453 #define FSG_HS_FUNCTION_PRE_EP_ENTRIES  2
 454
 455 /* Maxpacket and other transfer characteristics vary by speed. */
 456 static struct usb_endpoint_descriptor *
 457 fsg_ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
 458                 struct usb_endpoint_descriptor *hs)
 459 {
 460         if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
 461                 return hs;
 462         return fs;
 463 }
 464
 465
 466 /* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
 467 static struct usb_string                fsg_strings[] = {
 468         {FSG_STRING_MANUFACTURER,       fsg_string_manufacturer},
 469         {FSG_STRING_PRODUCT,            fsg_string_product},
 470         {FSG_STRING_SERIAL,             fsg_string_serial},
 471         {FSG_STRING_CONFIG,             fsg_string_config},
 472         {FSG_STRING_INTERFACE,          fsg_string_interface},
 473         {}
 474 };
 475
 476 static struct usb_gadget_strings        fsg_stringtab = {
 477         .language       = 0x0409,               // en-us
 478         .strings        = fsg_strings,
 479 };
 480
 481
 482  /*-------------------------------------------------------------------------*/
 483
 484 /* If the next two routines are called while the gadget is registered,
 485  * the caller must own fsg->filesem for writing. */
 486
 487 static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 488 {
 489         int                             ro;
 490         struct file                     *filp = NULL;
 491         int                             rc = -EINVAL;
 492         struct inode                    *inode = NULL;
 493         loff_t                          size;
 494         loff_t                          num_sectors;
 495         loff_t                          min_sectors;
 496
 497         /* R/W if we can, R/O if we must */
 498         ro = curlun->initially_ro;
 499         if (!ro) {
 500                 filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
 501                 if (-EROFS == PTR_ERR(filp))
 502                         ro = 1;
 503         }
 504         if (ro)
 505                 filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
 506         if (IS_ERR(filp)) {
 507                 LINFO(curlun, "unable to open backing file: %s\n", filename);
 508                 return PTR_ERR(filp);
 509         }
 510
 511         if (!(filp->f_mode & FMODE_WRITE))
 512                 ro = 1;
 513
 514         if (filp->f_path.dentry)
 515                 inode = filp->f_path.dentry->d_inode;
 516         if (inode && S_ISBLK(inode->i_mode)) {
 517                 if (bdev_read_only(inode->i_bdev))
 518                         ro = 1;
 519         } else if (!inode || !S_ISREG(inode->i_mode)) {
 520                 LINFO(curlun, "invalid file type: %s\n", filename);
 521                 goto out;
 522         }
 523
 524         /* If we can't read the file, it's no good.
 525          * If we can't write the file, use it read-only. */
 526         if (!filp->f_op || !(filp->f_op->read || filp->f_op->aio_read)) {
 527                 LINFO(curlun, "file not readable: %s\n", filename);
 528                 goto out;
 529         }
 530         if (!(filp->f_op->write || filp->f_op->aio_write))
 531                 ro = 1;
 532
 533         size = i_size_read(inode->i_mapping->host);
 534         if (size < 0) {
 535                 LINFO(curlun, "unable to find file size: %s\n", filename);
 536                 rc = (int) size;
 537                 goto out;
 538         }
 539         num_sectors = size >> 9;        // File size in 512-byte blocks
 540         min_sectors = 1;
 541         if (curlun->cdrom) {
 542                 num_sectors &= ~3;      // Reduce to a multiple of 2048
 543                 min_sectors = 300*4;    // Smallest track is 300 frames
 544                 if (num_sectors >= 256*60*75*4) {
 545                         num_sectors = (256*60*75 - 1) * 4;
 546                         LINFO(curlun, "file too big: %s\n", filename);
 547                         LINFO(curlun, "using only first %d blocks\n",
 548                                         (int) num_sectors);
 549                 }
 550         }
 551         if (num_sectors < min_sectors) {
 552                 LINFO(curlun, "file too small: %s\n", filename);
 553                 rc = -ETOOSMALL;
 554                 goto out;
 555         }
 556
 557         get_file(filp);
 558         curlun->ro = ro;
 559         curlun->filp = filp;
 560         curlun->file_length = size;
 561         curlun->num_sectors = num_sectors;
 562         LDBG(curlun, "open backing file: %s\n", filename);
 563         rc = 0;
 564
 565 out:
 566         filp_close(filp, current->files);
 567         return rc;
 568 }
 569
 570
 571 static void fsg_lun_close(struct fsg_lun *curlun)
 572 {
 573         if (curlun->filp) {
 574                 LDBG(curlun, "close backing file\n");
 575                 fput(curlun->filp);
 576                 curlun->filp = NULL;
 577         }
 578 }
 579
 580
 581 /*-------------------------------------------------------------------------*/
 582
 583 /* Sync the file data, don't bother with the metadata.
 584  * This code was copied from fs/buffer.c:sys_fdatasync(). */
 585 static int fsg_lun_fsync_sub(struct fsg_lun *curlun)
 586 {
 587         struct file     *filp = curlun->filp;
 588
 589         if (curlun->ro || !filp)
 590                 return 0;
 591         return vfs_fsync(filp, filp->f_path.dentry, 1);
 592 }
 593
 594 static void store_cdrom_address(u8 *dest, int msf, u32 addr)
 595 {
 596         if (msf) {
 597                 /* Convert to Minutes-Seconds-Frames */
 598                 addr >>= 2;             /* Convert to 2048-byte frames */
 599                 addr += 2*75;           /* Lead-in occupies 2 seconds */
 600                 dest[3] = addr % 75;    /* Frames */
 601                 addr /= 75;
 602                 dest[2] = addr % 60;    /* Seconds */
 603                 addr /= 60;
 604                 dest[1] = addr;         /* Minutes */
 605                 dest[0] = 0;            /* Reserved */
 606         } else {
 607                 /* Absolute sector */
 608                 put_unaligned_be32(addr, dest);
 609         }
 610 }
 611
 612
 613 /*-------------------------------------------------------------------------*/
 614
 615
 616 static ssize_t fsg_show_ro(struct device *dev, struct device_attribute *attr,
 617                            char *buf)
 618 {
 619         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 620
 621         return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
 622                                   ? curlun->ro
 623                                   : curlun->initially_ro);
 624 }
 625
 626 static ssize_t fsg_show_file(struct device *dev, struct device_attribute *attr,
 627                              char *buf)
 628 {
 629         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 630         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 631         char            *p;
 632         ssize_t         rc;
 633
 634         down_read(filesem);
 635         if (fsg_lun_is_open(curlun)) {  // Get the complete pathname
 636                 p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1);
 637                 if (IS_ERR(p))
 638                         rc = PTR_ERR(p);
 639                 else {
 640                         rc = strlen(p);
 641                         memmove(buf, p, rc);
 642                         buf[rc] = '\n';         // Add a newline
 643                         buf[++rc] = 0;
 644                 }
 645         } else {                                // No file, return 0 bytes
 646                 *buf = 0;
 647                 rc = 0;
 648         }
 649         up_read(filesem);
 650         return rc;
 651 }
 652
 653
 654 static ssize_t fsg_store_ro(struct device *dev, struct device_attribute *attr,
 655                             const char *buf, size_t count)
 656 {
 657         ssize_t         rc = count;
 658         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 659         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 660         int             i;
 661
 662         if (sscanf(buf, "%d", &i) != 1)
 663                 return -EINVAL;
 664
 665         /* Allow the write-enable status to change only while the backing file
 666          * is closed. */
 667         down_read(filesem);
 668         if (fsg_lun_is_open(curlun)) {
 669                 LDBG(curlun, "read-only status change prevented\n");
 670                 rc = -EBUSY;
 671         } else {
 672                 curlun->ro = !!i;
 673                 curlun->initially_ro = !!i;
 674                 LDBG(curlun, "read-only status set to %d\n", curlun->ro);
 675         }
 676         up_read(filesem);
 677         return rc;
 678 }
 679
 680 static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr,
 681                               const char *buf, size_t count)
 682 {
 683         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 684         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 685         int             rc = 0;
 686
 687         if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
 688                 LDBG(curlun, "eject attempt prevented\n");
 689                 return -EBUSY;                          // "Door is locked"
 690         }
 691
 692         /* Remove a trailing newline */
 693         if (count > 0 && buf[count-1] == '\n')
 694                 ((char *) buf)[count-1] = 0;            // Ugh!
 695
 696         /* Eject current medium */
 697         down_write(filesem);
 698         if (fsg_lun_is_open(curlun)) {
 699                 fsg_lun_close(curlun);
 700                 curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
 701         }
 702
 703         /* Load new medium */
 704         if (count > 0 && buf[0]) {
 705                 rc = fsg_lun_open(curlun, buf);
 706                 if (rc == 0)
 707                         curlun->unit_attention_data =
 708                                         SS_NOT_READY_TO_READY_TRANSITION;
 709         }
 710         up_write(filesem);
 711         return (rc < 0 ? rc : count);
 712 }