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 (mina86@mina86.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
  14 /*
  15  * This file requires the following identifiers used in USB strings to
  16  * be defined (each of type pointer to char):
  17  *  - fsg_string_interface    -- name of the interface
  18  */
  19
  20 /*
  21  * When USB_GADGET_DEBUG_FILES is defined the module param num_buffers
  22  * sets the number of pipeline buffers (length of the fsg_buffhd array).
  23  * The valid range of num_buffers is: num >= 2 && num <= 4.
  24  */
  25
  26
  27 #include <linux/usb/storage.h>
  28 #include <scsi/scsi.h>
  29 #include <asm/unaligned.h>
  30
  31
  32 /*
  33  * Thanks to NetChip Technologies for donating this product ID.
  34  *
  35  * DO NOT REUSE THESE IDs with any other driver!!  Ever!!
  36  * Instead:  allocate your own, using normal USB-IF procedures.
  37  */
  38 #define FSG_VENDOR_ID   0x0525  /* NetChip */
  39 #define FSG_PRODUCT_ID  0xa4a5  /* Linux-USB File-backed Storage Gadget */
  40
  41
  42 /*-------------------------------------------------------------------------*/
  43
  44
  45 #ifndef DEBUG
  46 #undef VERBOSE_DEBUG
  47 #undef DUMP_MSGS
  48 #endif /* !DEBUG */
  49
  50 #ifdef VERBOSE_DEBUG
  51 #define VLDBG   LDBG
  52 #else
  53 #define VLDBG(lun, fmt, args...) do { } while (0)
  54 #endif /* VERBOSE_DEBUG */
  55
  56 #define LDBG(lun, fmt, args...)   dev_dbg (&(lun)->dev, fmt, ## args)
  57 #define LERROR(lun, fmt, args...) dev_err (&(lun)->dev, fmt, ## args)
  58 #define LWARN(lun, fmt, args...)  dev_warn(&(lun)->dev, fmt, ## args)
  59 #define LINFO(lun, fmt, args...)  dev_info(&(lun)->dev, fmt, ## args)
  60
  61
  62 #ifdef DUMP_MSGS
  63
  64 #  define dump_msg(fsg, /* const char * */ label,                       \
  65                    /* const u8 * */ buf, /* unsigned */ length) do {    \
  66         if (length < 512) {                                             \
  67                 DBG(fsg, "%s, length %u:\n", label, length);            \
  68                 print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET,      \
  69                                16, 1, buf, length, 0);                  \
  70         }                                                               \
  71 } while (0)
  72
  73 #  define dump_cdb(fsg) do { } while (0)
  74
  75 #else
  76
  77 #  define dump_msg(fsg, /* const char * */ label, \
  78                    /* const u8 * */ buf, /* unsigned */ length) do { } while (0)
  79
  80 #  ifdef VERBOSE_DEBUG
  81
  82 #    define dump_cdb(fsg)                                               \
  83         print_hex_dump(KERN_DEBUG, "SCSI CDB: ", DUMP_PREFIX_NONE,      \
  84                        16, 1, (fsg)->cmnd, (fsg)->cmnd_size, 0)         \
  85
  86 #  else
  87
  88 #    define dump_cdb(fsg) do { } while (0)
  89
  90 #  endif /* VERBOSE_DEBUG */
  91
  92 #endif /* DUMP_MSGS */
  93
  94 /*-------------------------------------------------------------------------*/
  95
  96 /* CBI Interrupt data structure */
  97 struct interrupt_data {
  98         u8      bType;
  99         u8      bValue;
 100 };
 101
 102 #define CBI_INTERRUPT_DATA_LEN          2
 103
 104 /* CBI Accept Device-Specific Command request */
 105 #define USB_CBI_ADSC_REQUEST            0x00
 106
 107
 108 /* Length of a SCSI Command Data Block */
 109 #define MAX_COMMAND_SIZE        16
 110
 111 /* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
 112 #define SS_NO_SENSE                             0
 113 #define SS_COMMUNICATION_FAILURE                0x040800
 114 #define SS_INVALID_COMMAND                      0x052000
 115 #define SS_INVALID_FIELD_IN_CDB                 0x052400
 116 #define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE   0x052100
 117 #define SS_LOGICAL_UNIT_NOT_SUPPORTED           0x052500
 118 #define SS_MEDIUM_NOT_PRESENT                   0x023a00
 119 #define SS_MEDIUM_REMOVAL_PREVENTED             0x055302
 120 #define SS_NOT_READY_TO_READY_TRANSITION        0x062800
 121 #define SS_RESET_OCCURRED                       0x062900
 122 #define SS_SAVING_PARAMETERS_NOT_SUPPORTED      0x053900
 123 #define SS_UNRECOVERED_READ_ERROR               0x031100
 124 #define SS_WRITE_ERROR                          0x030c02
 125 #define SS_WRITE_PROTECTED                      0x072700
 126
 127 #define SK(x)           ((u8) ((x) >> 16))      /* Sense Key byte, etc. */
 128 #define ASC(x)          ((u8) ((x) >> 8))
 129 #define ASCQ(x)         ((u8) (x))
 130
 131
 132 /*-------------------------------------------------------------------------*/
 133
 134
 135 struct fsg_lun {
 136         struct file     *filp;
 137         loff_t          file_length;
 138         loff_t          num_sectors;
 139
 140         unsigned int    initially_ro:1;
 141         unsigned int    ro:1;
 142         unsigned int    removable:1;
 143         unsigned int    cdrom:1;
 144         unsigned int    prevent_medium_removal:1;
 145         unsigned int    registered:1;
 146         unsigned int    info_valid:1;
 147         unsigned int    nofua:1;
 148
 149         u32             sense_data;
 150         u32             sense_data_info;
 151         u32             unit_attention_data;
 152
 153         unsigned int    blkbits;        /* Bits of logical block size of bound block device */
 154         unsigned int    blksize;        /* logical block size of bound block device */
 155         struct device   dev;
 156 };
 157
 158 static inline bool fsg_lun_is_open(struct fsg_lun *curlun)
 159 {
 160         return curlun->filp != NULL;
 161 }
 162
 163 static inline struct fsg_lun *fsg_lun_from_dev(struct device *dev)
 164 {
 165         return container_of(dev, struct fsg_lun, dev);
 166 }
 167
 168
 169 /* Big enough to hold our biggest descriptor */
 170 #define EP0_BUFSIZE     256
 171 #define DELAYED_STATUS  (EP0_BUFSIZE + 999)     /* An impossibly large value */
 172
 173 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
 174
 175 static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS;
 176 module_param_named(num_buffers, fsg_num_buffers, uint, S_IRUGO);
 177 MODULE_PARM_DESC(num_buffers, "Number of pipeline buffers");
 178
 179 #else
 180
 181 /*
 182  * Number of buffers we will use.
 183  * 2 is usually enough for good buffering pipeline
 184  */
 185 #define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS
 186
 187 #endif /* CONFIG_USB_DEBUG */
 188
 189 /* check if fsg_num_buffers is within a valid range */
 190 static inline int fsg_num_buffers_validate(void)
 191 {
 192         if (fsg_num_buffers >= 2 && fsg_num_buffers <= 4)
 193                 return 0;
 194         pr_err("fsg_num_buffers %u is out of range (%d to %d)\n",
 195                fsg_num_buffers, 2 ,4);
 196         return -EINVAL;
 197 }
 198
 199 /* Default size of buffer length. */
 200 #define FSG_BUFLEN      ((u32)16384)
 201
 202 /* Maximal number of LUNs supported in mass storage function */
 203 #define FSG_MAX_LUNS    8
 204
 205 enum fsg_buffer_state {
 206         BUF_STATE_EMPTY = 0,
 207         BUF_STATE_FULL,
 208         BUF_STATE_BUSY
 209 };
 210
 211 struct fsg_buffhd {
 212         void                            *buf;
 213         enum fsg_buffer_state           state;
 214         struct fsg_buffhd               *next;
 215
 216         /*
 217          * The NetChip 2280 is faster, and handles some protocol faults
 218          * better, if we don't submit any short bulk-out read requests.
 219          * So we will record the intended request length here.
 220          */
 221         unsigned int                    bulk_out_intended_length;
 222
 223         struct usb_request              *inreq;
 224         int                             inreq_busy;
 225         struct usb_request              *outreq;
 226         int                             outreq_busy;
 227 };
 228
 229 enum fsg_state {
 230         /* This one isn't used anywhere */
 231         FSG_STATE_COMMAND_PHASE = -10,
 232         FSG_STATE_DATA_PHASE,
 233         FSG_STATE_STATUS_PHASE,
 234
 235         FSG_STATE_IDLE = 0,
 236         FSG_STATE_ABORT_BULK_OUT,
 237         FSG_STATE_RESET,
 238         FSG_STATE_INTERFACE_CHANGE,
 239         FSG_STATE_CONFIG_CHANGE,
 240         FSG_STATE_DISCONNECT,
 241         FSG_STATE_EXIT,
 242         FSG_STATE_TERMINATED
 243 };
 244
 245 enum data_direction {
 246         DATA_DIR_UNKNOWN = 0,
 247         DATA_DIR_FROM_HOST,
 248         DATA_DIR_TO_HOST,
 249         DATA_DIR_NONE
 250 };
 251
 252
 253 /*-------------------------------------------------------------------------*/
 254
 255
 256 static inline u32 get_unaligned_be24(u8 *buf)
 257 {
 258         return 0xffffff & (u32) get_unaligned_be32(buf - 1);
 259 }
 260
 261
 262 /*-------------------------------------------------------------------------*/
 263
 264
 265 enum {
 266         FSG_STRING_INTERFACE
 267 };
 268
 269
 270 /* There is only one interface. */
 271
 272 static struct usb_interface_descriptor
 273 fsg_intf_desc = {
 274         .bLength =              sizeof fsg_intf_desc,
 275         .bDescriptorType =      USB_DT_INTERFACE,
 276
 277         .bNumEndpoints =        2,              /* Adjusted during fsg_bind() */
 278         .bInterfaceClass =      USB_CLASS_MASS_STORAGE,
 279         .bInterfaceSubClass =   USB_SC_SCSI,    /* Adjusted during fsg_bind() */
 280         .bInterfaceProtocol =   USB_PR_BULK,    /* Adjusted during fsg_bind() */
 281         .iInterface =           FSG_STRING_INTERFACE,
 282 };
 283
 284 /*
 285  * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
 286  * interrupt-in.
 287  */
 288
 289 static struct usb_endpoint_descriptor
 290 fsg_fs_bulk_in_desc = {
 291         .bLength =              USB_DT_ENDPOINT_SIZE,
 292         .bDescriptorType =      USB_DT_ENDPOINT,
 293
 294         .bEndpointAddress =     USB_DIR_IN,
 295         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 296         /* wMaxPacketSize set by autoconfiguration */
 297 };
 298
 299 static struct usb_endpoint_descriptor
 300 fsg_fs_bulk_out_desc = {
 301         .bLength =              USB_DT_ENDPOINT_SIZE,
 302         .bDescriptorType =      USB_DT_ENDPOINT,
 303
 304         .bEndpointAddress =     USB_DIR_OUT,
 305         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 306         /* wMaxPacketSize set by autoconfiguration */
 307 };
 308
 309 static struct usb_descriptor_header *fsg_fs_function[] = {
 310         (struct usb_descriptor_header *) &fsg_intf_desc,
 311         (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
 312         (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
 313         NULL,
 314 };
 315
 316
 317 /*
 318  * USB 2.0 devices need to expose both high speed and full speed
 319  * descriptors, unless they only run at full speed.
 320  *
 321  * That means alternate endpoint descriptors (bigger packets)
 322  * and a "device qualifier" ... plus more construction options
 323  * for the configuration descriptor.
 324  */
 325 static struct usb_endpoint_descriptor
 326 fsg_hs_bulk_in_desc = {
 327         .bLength =              USB_DT_ENDPOINT_SIZE,
 328         .bDescriptorType =      USB_DT_ENDPOINT,
 329
 330         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 331         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 332         .wMaxPacketSize =       cpu_to_le16(512),
 333 };
 334
 335 static struct usb_endpoint_descriptor
 336 fsg_hs_bulk_out_desc = {
 337         .bLength =              USB_DT_ENDPOINT_SIZE,
 338         .bDescriptorType =      USB_DT_ENDPOINT,
 339
 340         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 341         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 342         .wMaxPacketSize =       cpu_to_le16(512),
 343         .bInterval =            1,      /* NAK every 1 uframe */
 344 };
 345
 346
 347 static struct usb_descriptor_header *fsg_hs_function[] = {
 348         (struct usb_descriptor_header *) &fsg_intf_desc,
 349         (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
 350         (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
 351         NULL,
 352 };
 353
 354 static struct usb_endpoint_descriptor
 355 fsg_ss_bulk_in_desc = {
 356         .bLength =              USB_DT_ENDPOINT_SIZE,
 357         .bDescriptorType =      USB_DT_ENDPOINT,
 358
 359         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 360         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 361         .wMaxPacketSize =       cpu_to_le16(1024),
 362 };
 363
 364 static struct usb_ss_ep_comp_descriptor fsg_ss_bulk_in_comp_desc = {
 365         .bLength =              sizeof(fsg_ss_bulk_in_comp_desc),
 366         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 367
 368         /*.bMaxBurst =          DYNAMIC, */
 369 };
 370
 371 static struct usb_endpoint_descriptor
 372 fsg_ss_bulk_out_desc = {
 373         .bLength =              USB_DT_ENDPOINT_SIZE,
 374         .bDescriptorType =      USB_DT_ENDPOINT,
 375
 376         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 377         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 378         .wMaxPacketSize =       cpu_to_le16(1024),
 379 };
 380
 381 static struct usb_ss_ep_comp_descriptor fsg_ss_bulk_out_comp_desc = {
 382         .bLength =              sizeof(fsg_ss_bulk_in_comp_desc),
 383         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 384
 385         /*.bMaxBurst =          DYNAMIC, */
 386 };
 387
 388 static __maybe_unused struct usb_ext_cap_descriptor fsg_ext_cap_desc = {
 389         .bLength =              USB_DT_USB_EXT_CAP_SIZE,
 390         .bDescriptorType =      USB_DT_DEVICE_CAPABILITY,
 391         .bDevCapabilityType =   USB_CAP_TYPE_EXT,
 392
 393         .bmAttributes =         cpu_to_le32(USB_LPM_SUPPORT),
 394 };
 395
 396 static __maybe_unused struct usb_ss_cap_descriptor fsg_ss_cap_desc = {
 397         .bLength =              USB_DT_USB_SS_CAP_SIZE,
 398         .bDescriptorType =      USB_DT_DEVICE_CAPABILITY,
 399         .bDevCapabilityType =   USB_SS_CAP_TYPE,
 400
 401         /* .bmAttributes = LTM is not supported yet */
 402
 403         .wSpeedSupported =      cpu_to_le16(USB_LOW_SPEED_OPERATION
 404                 | USB_FULL_SPEED_OPERATION
 405                 | USB_HIGH_SPEED_OPERATION
 406                 | USB_5GBPS_OPERATION),
 407         .bFunctionalitySupport = USB_LOW_SPEED_OPERATION,
 408         .bU1devExitLat =        USB_DEFAULT_U1_DEV_EXIT_LAT,
 409         .bU2DevExitLat =        cpu_to_le16(USB_DEFAULT_U2_DEV_EXIT_LAT),
 410 };
 411
 412 static __maybe_unused struct usb_bos_descriptor fsg_bos_desc = {
 413         .bLength =              USB_DT_BOS_SIZE,
 414         .bDescriptorType =      USB_DT_BOS,
 415
 416         .wTotalLength =         cpu_to_le16(USB_DT_BOS_SIZE
 417                                 + USB_DT_USB_EXT_CAP_SIZE
 418                                 + USB_DT_USB_SS_CAP_SIZE),
 419
 420         .bNumDeviceCaps =       2,
 421 };
 422
 423 static struct usb_descriptor_header *fsg_ss_function[] = {
 424         (struct usb_descriptor_header *) &fsg_intf_desc,
 425         (struct usb_descriptor_header *) &fsg_ss_bulk_in_desc,
 426         (struct usb_descriptor_header *) &fsg_ss_bulk_in_comp_desc,
 427         (struct usb_descriptor_header *) &fsg_ss_bulk_out_desc,
 428         (struct usb_descriptor_header *) &fsg_ss_bulk_out_comp_desc,
 429         NULL,
 430 };
 431
 432 /* Maxpacket and other transfer characteristics vary by speed. */
 433 static __maybe_unused struct usb_endpoint_descriptor *
 434 fsg_ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
 435                 struct usb_endpoint_descriptor *hs,
 436                 struct usb_endpoint_descriptor *ss)
 437 {
 438         if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
 439                 return ss;
 440         else if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
 441                 return hs;
 442         return fs;
 443 }
 444
 445
 446 /* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
 447 static struct usb_string                fsg_strings[] = {
 448         {FSG_STRING_INTERFACE,          fsg_string_interface},
 449         {}
 450 };
 451
 452 static struct usb_gadget_strings        fsg_stringtab = {
 453         .language       = 0x0409,               /* en-us */
 454         .strings        = fsg_strings,
 455 };
 456
 457
 458  /*-------------------------------------------------------------------------*/
 459
 460 /*
 461  * If the next two routines are called while the gadget is registered,
 462  * the caller must own fsg->filesem for writing.
 463  */
 464
 465 static void fsg_lun_close(struct fsg_lun *curlun)
 466 {
 467         if (curlun->filp) {
 468                 LDBG(curlun, "close backing file\n");
 469                 fput(curlun->filp);
 470                 curlun->filp = NULL;
 471         }
 472 }
 473
 474
 475 static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 476 {
 477         int                             ro;
 478         struct file                     *filp = NULL;
 479         int                             rc = -EINVAL;
 480         struct inode                    *inode = NULL;
 481         loff_t                          size;
 482         loff_t                          num_sectors;
 483         loff_t                          min_sectors;
 484         unsigned int                    blkbits;
 485         unsigned int                    blksize;
 486
 487         /* R/W if we can, R/O if we must */
 488         ro = curlun->initially_ro;
 489         if (!ro) {
 490                 filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
 491                 if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
 492                         ro = 1;
 493         }
 494         if (ro)
 495                 filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
 496         if (IS_ERR(filp)) {
 497                 LINFO(curlun, "unable to open backing file: %s\n", filename);
 498                 return PTR_ERR(filp);
 499         }
 500
 501         if (!(filp->f_mode & FMODE_WRITE))
 502                 ro = 1;
 503
 504         inode = filp->f_path.dentry->d_inode;
 505         if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
 506                 LINFO(curlun, "invalid file type: %s\n", filename);
 507                 goto out;
 508         }
 509
 510         /*
 511          * If we can't read the file, it's no good.
 512          * If we can't write the file, use it read-only.
 513          */
 514         if (!(filp->f_op->read || filp->f_op->aio_read)) {
 515                 LINFO(curlun, "file not readable: %s\n", filename);
 516                 goto out;
 517         }
 518         if (!(filp->f_op->write || filp->f_op->aio_write))
 519                 ro = 1;
 520
 521         size = i_size_read(inode->i_mapping->host);
 522         if (size < 0) {
 523                 LINFO(curlun, "unable to find file size: %s\n", filename);
 524                 rc = (int) size;
 525                 goto out;
 526         }
 527
 528         if (curlun->cdrom) {
 529                 blksize = 2048;
 530                 blkbits = 11;
 531         } else if (inode->i_bdev) {
 532                 blksize = bdev_logical_block_size(inode->i_bdev);
 533                 blkbits = blksize_bits(blksize);
 534         } else {
 535                 blksize = 512;
 536                 blkbits = 9;
 537         }
 538
 539         num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
 540         min_sectors = 1;
 541         if (curlun->cdrom) {
 542                 min_sectors = 300;      /* Smallest track is 300 frames */
 543                 if (num_sectors >= 256*60*75) {
 544                         num_sectors = 256*60*75 - 1;
 545                         LINFO(curlun, "file too big: %s\n", filename);
 546                         LINFO(curlun, "using only first %d blocks\n",
 547                                         (int) num_sectors);
 548                 }
 549         }
 550         if (num_sectors < min_sectors) {
 551                 LINFO(curlun, "file too small: %s\n", filename);
 552                 rc = -ETOOSMALL;
 553                 goto out;
 554         }
 555
 556         if (fsg_lun_is_open(curlun))
 557                 fsg_lun_close(curlun);
 558
 559         curlun->blksize = blksize;
 560         curlun->blkbits = blkbits;
 561         curlun->ro = ro;
 562         curlun->filp = filp;
 563         curlun->file_length = size;
 564         curlun->num_sectors = num_sectors;
 565         LDBG(curlun, "open backing file: %s\n", filename);
 566         return 0;
 567
 568 out:
 569         fput(filp);
 570         return rc;
 571 }
 572
 573
 574 /*-------------------------------------------------------------------------*/
 575
 576 /*
 577  * Sync the file data, don't bother with the metadata.
 578  * This code was copied from fs/buffer.c:sys_fdatasync().
 579  */
 580 static int fsg_lun_fsync_sub(struct fsg_lun *curlun)
 581 {
 582         struct file     *filp = curlun->filp;
 583
 584         if (curlun->ro || !filp)
 585                 return 0;
 586         return vfs_fsync(filp, 1);
 587 }
 588
 589 static void store_cdrom_address(u8 *dest, int msf, u32 addr)
 590 {
 591         if (msf) {
 592                 /* Convert to Minutes-Seconds-Frames */
 593                 addr >>= 2;             /* Convert to 2048-byte frames */
 594                 addr += 2*75;           /* Lead-in occupies 2 seconds */
 595                 dest[3] = addr % 75;    /* Frames */
 596                 addr /= 75;
 597                 dest[2] = addr % 60;    /* Seconds */
 598                 addr /= 60;
 599                 dest[1] = addr;         /* Minutes */
 600                 dest[0] = 0;            /* Reserved */
 601         } else {
 602                 /* Absolute sector */
 603                 put_unaligned_be32(addr, dest);
 604         }
 605 }
 606
 607
 608 /*-------------------------------------------------------------------------*/
 609
 610
 611 static ssize_t fsg_show_ro(struct device *dev, struct device_attribute *attr,
 612                            char *buf)
 613 {
 614         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 615
 616         return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
 617                                   ? curlun->ro
 618                                   : curlun->initially_ro);
 619 }
 620
 621 static ssize_t fsg_show_nofua(struct device *dev, struct device_attribute *attr,
 622                               char *buf)
 623 {
 624         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 625
 626         return sprintf(buf, "%u\n", curlun->nofua);
 627 }
 628
 629 static ssize_t fsg_show_file(struct device *dev, struct device_attribute *attr,
 630                              char *buf)
 631 {
 632         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 633         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 634         char            *p;
 635         ssize_t         rc;
 636
 637         down_read(filesem);
 638         if (fsg_lun_is_open(curlun)) {  /* Get the complete pathname */
 639                 p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1);
 640                 if (IS_ERR(p))
 641                         rc = PTR_ERR(p);
 642                 else {
 643                         rc = strlen(p);
 644                         memmove(buf, p, rc);
 645                         buf[rc] = '\n';         /* Add a newline */
 646                         buf[++rc] = 0;
 647                 }
 648         } else {                                /* No file, return 0 bytes */
 649                 *buf = 0;
 650                 rc = 0;
 651         }
 652         up_read(filesem);
 653         return rc;
 654 }
 655
 656
 657 static ssize_t fsg_store_ro(struct device *dev, struct device_attribute *attr,
 658                             const char *buf, size_t count)
 659 {
 660         ssize_t         rc;
 661         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 662         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 663         unsigned        ro;
 664
 665         rc = kstrtouint(buf, 2, &ro);
 666         if (rc)
 667                 return rc;
 668
 669         /*
 670          * Allow the write-enable status to change only while the
 671          * backing file is closed.
 672          */
 673         down_read(filesem);
 674         if (fsg_lun_is_open(curlun)) {
 675                 LDBG(curlun, "read-only status change prevented\n");
 676                 rc = -EBUSY;
 677         } else {
 678                 curlun->ro = ro;
 679                 curlun->initially_ro = ro;
 680                 LDBG(curlun, "read-only status set to %d\n", curlun->ro);
 681                 rc = count;
 682         }
 683         up_read(filesem);
 684         return rc;
 685 }
 686
 687 static ssize_t fsg_store_nofua(struct device *dev,
 688                                struct device_attribute *attr,
 689                                const char *buf, size_t count)
 690 {
 691         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 692         unsigned        nofua;
 693         int             ret;
 694
 695         ret = kstrtouint(buf, 2, &nofua);
 696         if (ret)
 697                 return ret;
 698
 699         /* Sync data when switching from async mode to sync */
 700         if (!nofua && curlun->nofua)
 701                 fsg_lun_fsync_sub(curlun);
 702
 703         curlun->nofua = nofua;
 704
 705         return count;
 706 }
 707
 708 static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr,
 709                               const char *buf, size_t count)
 710 {
 711         struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
 712         struct rw_semaphore     *filesem = dev_get_drvdata(dev);
 713         int             rc = 0;
 714
 715         if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
 716                 LDBG(curlun, "eject attempt prevented\n");
 717                 return -EBUSY;                          /* "Door is locked" */
 718         }
 719
 720         /* Remove a trailing newline */
 721         if (count > 0 && buf[count-1] == '\n')
 722                 ((char *) buf)[count-1] = 0;            /* Ugh! */
 723
 724         /* Load new medium */
 725         down_write(filesem);
 726         if (count > 0 && buf[0]) {
 727                 /* fsg_lun_open() will close existing file if any. */
 728                 rc = fsg_lun_open(curlun, buf);
 729                 if (rc == 0)
 730                         curlun->unit_attention_data =
 731                                         SS_NOT_READY_TO_READY_TRANSITION;
 732         } else if (fsg_lun_is_open(curlun)) {
 733                 fsg_lun_close(curlun);
 734                 curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
 735         }
 736         up_write(filesem);
 737         return (rc < 0 ? rc : count);
 738 }