drivers/usb/gadget/function/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 #include <linux/module.h>
  27 #include <linux/blkdev.h>
  28 #include <linux/file.h>
  29 #include <linux/fs.h>
  30 #include <linux/usb/composite.h>
  31
  32 #include "storage_common.h"
  33
  34 /* There is only one interface. */
  35
  36 struct usb_interface_descriptor fsg_intf_desc = {
  37         .bLength =              sizeof fsg_intf_desc,
  38         .bDescriptorType =      USB_DT_INTERFACE,
  39
  40         .bNumEndpoints =        2,              /* Adjusted during fsg_bind() */
  41         .bInterfaceClass =      USB_CLASS_MASS_STORAGE,
  42         .bInterfaceSubClass =   USB_SC_SCSI,    /* Adjusted during fsg_bind() */
  43         .bInterfaceProtocol =   USB_PR_BULK,    /* Adjusted during fsg_bind() */
  44         .iInterface =           FSG_STRING_INTERFACE,
  45 };
  46 EXPORT_SYMBOL_GPL(fsg_intf_desc);
  47
  48 /*
  49  * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
  50  * interrupt-in.
  51  */
  52
  53 struct usb_endpoint_descriptor fsg_fs_bulk_in_desc = {
  54         .bLength =              USB_DT_ENDPOINT_SIZE,
  55         .bDescriptorType =      USB_DT_ENDPOINT,
  56
  57         .bEndpointAddress =     USB_DIR_IN,
  58         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  59         /* wMaxPacketSize set by autoconfiguration */
  60 };
  61 EXPORT_SYMBOL_GPL(fsg_fs_bulk_in_desc);
  62
  63 struct usb_endpoint_descriptor fsg_fs_bulk_out_desc = {
  64         .bLength =              USB_DT_ENDPOINT_SIZE,
  65         .bDescriptorType =      USB_DT_ENDPOINT,
  66
  67         .bEndpointAddress =     USB_DIR_OUT,
  68         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  69         /* wMaxPacketSize set by autoconfiguration */
  70 };
  71 EXPORT_SYMBOL_GPL(fsg_fs_bulk_out_desc);
  72
  73 struct usb_descriptor_header *fsg_fs_function[] = {
  74         (struct usb_descriptor_header *) &fsg_intf_desc,
  75         (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
  76         (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
  77         NULL,
  78 };
  79 EXPORT_SYMBOL_GPL(fsg_fs_function);
  80
  81
  82 /*
  83  * USB 2.0 devices need to expose both high speed and full speed
  84  * descriptors, unless they only run at full speed.
  85  *
  86  * That means alternate endpoint descriptors (bigger packets)
  87  * and a "device qualifier" ... plus more construction options
  88  * for the configuration descriptor.
  89  */
  90 struct usb_endpoint_descriptor fsg_hs_bulk_in_desc = {
  91         .bLength =              USB_DT_ENDPOINT_SIZE,
  92         .bDescriptorType =      USB_DT_ENDPOINT,
  93
  94         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
  95         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
  96         .wMaxPacketSize =       cpu_to_le16(512),
  97 };
  98 EXPORT_SYMBOL_GPL(fsg_hs_bulk_in_desc);
  99
 100 struct usb_endpoint_descriptor fsg_hs_bulk_out_desc = {
 101         .bLength =              USB_DT_ENDPOINT_SIZE,
 102         .bDescriptorType =      USB_DT_ENDPOINT,
 103
 104         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 105         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 106         .wMaxPacketSize =       cpu_to_le16(512),
 107         .bInterval =            1,      /* NAK every 1 uframe */
 108 };
 109 EXPORT_SYMBOL_GPL(fsg_hs_bulk_out_desc);
 110
 111
 112 struct usb_descriptor_header *fsg_hs_function[] = {
 113         (struct usb_descriptor_header *) &fsg_intf_desc,
 114         (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
 115         (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
 116         NULL,
 117 };
 118 EXPORT_SYMBOL_GPL(fsg_hs_function);
 119
 120 struct usb_endpoint_descriptor fsg_ss_bulk_in_desc = {
 121         .bLength =              USB_DT_ENDPOINT_SIZE,
 122         .bDescriptorType =      USB_DT_ENDPOINT,
 123
 124         /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
 125         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 126         .wMaxPacketSize =       cpu_to_le16(1024),
 127 };
 128 EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_desc);
 129
 130 struct usb_ss_ep_comp_descriptor fsg_ss_bulk_in_comp_desc = {
 131         .bLength =              sizeof(fsg_ss_bulk_in_comp_desc),
 132         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 133
 134         /*.bMaxBurst =          DYNAMIC, */
 135 };
 136 EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_comp_desc);
 137
 138 struct usb_endpoint_descriptor fsg_ss_bulk_out_desc = {
 139         .bLength =              USB_DT_ENDPOINT_SIZE,
 140         .bDescriptorType =      USB_DT_ENDPOINT,
 141
 142         /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
 143         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 144         .wMaxPacketSize =       cpu_to_le16(1024),
 145 };
 146 EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_desc);
 147
 148 struct usb_ss_ep_comp_descriptor fsg_ss_bulk_out_comp_desc = {
 149         .bLength =              sizeof(fsg_ss_bulk_in_comp_desc),
 150         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 151
 152         /*.bMaxBurst =          DYNAMIC, */
 153 };
 154 EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_comp_desc);
 155
 156 struct usb_descriptor_header *fsg_ss_function[] = {
 157         (struct usb_descriptor_header *) &fsg_intf_desc,
 158         (struct usb_descriptor_header *) &fsg_ss_bulk_in_desc,
 159         (struct usb_descriptor_header *) &fsg_ss_bulk_in_comp_desc,
 160         (struct usb_descriptor_header *) &fsg_ss_bulk_out_desc,
 161         (struct usb_descriptor_header *) &fsg_ss_bulk_out_comp_desc,
 162         NULL,
 163 };
 164 EXPORT_SYMBOL_GPL(fsg_ss_function);
 165
 166
 167  /*-------------------------------------------------------------------------*/
 168
 169 /*
 170  * If the next two routines are called while the gadget is registered,
 171  * the caller must own fsg->filesem for writing.
 172  */
 173
 174 void fsg_lun_close(struct fsg_lun *curlun)
 175 {
 176         if (curlun->filp) {
 177                 LDBG(curlun, "close backing file\n");
 178                 fput(curlun->filp);
 179                 curlun->filp = NULL;
 180         }
 181 }
 182 EXPORT_SYMBOL_GPL(fsg_lun_close);
 183
 184 int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 185 {
 186         int                             ro;
 187         struct file                     *filp = NULL;
 188         int                             rc = -EINVAL;
 189         struct inode                    *inode = NULL;
 190         loff_t                          size;
 191         loff_t                          num_sectors;
 192         loff_t                          min_sectors;
 193         unsigned int                    blkbits;
 194         unsigned int                    blksize;
 195
 196         /* R/W if we can, R/O if we must */
 197         ro = curlun->initially_ro;
 198         if (!ro) {
 199                 filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
 200                 if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
 201                         ro = 1;
 202         }
 203         if (ro)
 204                 filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
 205         if (IS_ERR(filp)) {
 206                 LINFO(curlun, "unable to open backing file: %s\n", filename);
 207                 return PTR_ERR(filp);
 208         }
 209
 210         if (!(filp->f_mode & FMODE_WRITE))
 211                 ro = 1;
 212
 213         inode = file_inode(filp);
 214         if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
 215                 LINFO(curlun, "invalid file type: %s\n", filename);
 216                 goto out;
 217         }
 218
 219         /*
 220          * If we can't read the file, it's no good.
 221          * If we can't write the file, use it read-only.
 222          */
 223         if (!(filp->f_mode & FMODE_CAN_READ)) {
 224                 LINFO(curlun, "file not readable: %s\n", filename);
 225                 goto out;
 226         }
 227         if (!(filp->f_mode & FMODE_CAN_WRITE))
 228                 ro = 1;
 229
 230         size = i_size_read(inode->i_mapping->host);
 231         if (size < 0) {
 232                 LINFO(curlun, "unable to find file size: %s\n", filename);
 233                 rc = (int) size;
 234                 goto out;
 235         }
 236
 237         if (curlun->cdrom) {
 238                 blksize = 2048;
 239                 blkbits = 11;
 240         } else if (inode->i_bdev) {
 241                 blksize = bdev_logical_block_size(inode->i_bdev);
 242                 blkbits = blksize_bits(blksize);
 243         } else {
 244                 blksize = 512;
 245                 blkbits = 9;
 246         }
 247
 248         num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
 249         min_sectors = 1;
 250         if (curlun->cdrom) {
 251                 min_sectors = 300;      /* Smallest track is 300 frames */
 252                 if (num_sectors >= 256*60*75) {
 253                         num_sectors = 256*60*75 - 1;
 254                         LINFO(curlun, "file too big: %s\n", filename);
 255                         LINFO(curlun, "using only first %d blocks\n",
 256                                         (int) num_sectors);
 257                 }
 258         }
 259         if (num_sectors < min_sectors) {
 260                 LINFO(curlun, "file too small: %s\n", filename);
 261                 rc = -ETOOSMALL;
 262                 goto out;
 263         }
 264
 265         if (fsg_lun_is_open(curlun))
 266                 fsg_lun_close(curlun);
 267
 268         curlun->blksize = blksize;
 269         curlun->blkbits = blkbits;
 270         curlun->ro = ro;
 271         curlun->filp = filp;
 272         curlun->file_length = size;
 273         curlun->num_sectors = num_sectors;
 274         LDBG(curlun, "open backing file: %s\n", filename);
 275         return 0;
 276
 277 out:
 278         fput(filp);
 279         return rc;
 280 }
 281 EXPORT_SYMBOL_GPL(fsg_lun_open);
 282
 283
 284 /*-------------------------------------------------------------------------*/
 285
 286 /*
 287  * Sync the file data, don't bother with the metadata.
 288  * This code was copied from fs/buffer.c:sys_fdatasync().
 289  */
 290 int fsg_lun_fsync_sub(struct fsg_lun *curlun)
 291 {
 292         struct file     *filp = curlun->filp;
 293
 294         if (curlun->ro || !filp)
 295                 return 0;
 296         return vfs_fsync(filp, 1);
 297 }
 298 EXPORT_SYMBOL_GPL(fsg_lun_fsync_sub);
 299
 300 void store_cdrom_address(u8 *dest, int msf, u32 addr)
 301 {
 302         if (msf) {
 303                 /* Convert to Minutes-Seconds-Frames */
 304                 addr >>= 2;             /* Convert to 2048-byte frames */
 305                 addr += 2*75;           /* Lead-in occupies 2 seconds */
 306                 dest[3] = addr % 75;    /* Frames */
 307                 addr /= 75;
 308                 dest[2] = addr % 60;    /* Seconds */
 309                 addr /= 60;
 310                 dest[1] = addr;         /* Minutes */
 311                 dest[0] = 0;            /* Reserved */
 312         } else {
 313                 /* Absolute sector */
 314                 put_unaligned_be32(addr, dest);
 315         }
 316 }
 317 EXPORT_SYMBOL_GPL(store_cdrom_address);
 318
 319 /*-------------------------------------------------------------------------*/
 320
 321
 322 ssize_t fsg_show_ro(struct fsg_lun *curlun, char *buf)
 323 {
 324         return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
 325                                   ? curlun->ro
 326                                   : curlun->initially_ro);
 327 }
 328 EXPORT_SYMBOL_GPL(fsg_show_ro);
 329
 330 ssize_t fsg_show_nofua(struct fsg_lun *curlun, char *buf)
 331 {
 332         return sprintf(buf, "%u\n", curlun->nofua);
 333 }
 334 EXPORT_SYMBOL_GPL(fsg_show_nofua);
 335
 336 ssize_t fsg_show_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
 337                       char *buf)
 338 {
 339         char            *p;
 340         ssize_t         rc;
 341
 342         down_read(filesem);
 343         if (fsg_lun_is_open(curlun)) {  /* Get the complete pathname */
 344                 p = file_path(curlun->filp, buf, PAGE_SIZE - 1);
 345                 if (IS_ERR(p))
 346                         rc = PTR_ERR(p);
 347                 else {
 348                         rc = strlen(p);
 349                         memmove(buf, p, rc);
 350                         buf[rc] = '\n';         /* Add a newline */
 351                         buf[++rc] = 0;
 352                 }
 353         } else {                                /* No file, return 0 bytes */
 354                 *buf = 0;
 355                 rc = 0;
 356         }
 357         up_read(filesem);
 358         return rc;
 359 }
 360 EXPORT_SYMBOL_GPL(fsg_show_file);
 361
 362 ssize_t fsg_show_cdrom(struct fsg_lun *curlun, char *buf)
 363 {
 364         return sprintf(buf, "%u\n", curlun->cdrom);
 365 }
 366 EXPORT_SYMBOL_GPL(fsg_show_cdrom);
 367
 368 ssize_t fsg_show_removable(struct fsg_lun *curlun, char *buf)
 369 {
 370         return sprintf(buf, "%u\n", curlun->removable);
 371 }
 372 EXPORT_SYMBOL_GPL(fsg_show_removable);
 373
 374 /*
 375  * The caller must hold fsg->filesem for reading when calling this function.
 376  */
 377 static ssize_t _fsg_store_ro(struct fsg_lun *curlun, bool ro)
 378 {
 379         if (fsg_lun_is_open(curlun)) {
 380                 LDBG(curlun, "read-only status change prevented\n");
 381                 return -EBUSY;
 382         }
 383
 384         curlun->ro = ro;
 385         curlun->initially_ro = ro;
 386         LDBG(curlun, "read-only status set to %d\n", curlun->ro);
 387
 388         return 0;
 389 }
 390
 391 ssize_t fsg_store_ro(struct fsg_lun *curlun, struct rw_semaphore *filesem,
 392                      const char *buf, size_t count)
 393 {
 394         ssize_t         rc;
 395         bool            ro;
 396
 397         rc = strtobool(buf, &ro);
 398         if (rc)
 399                 return rc;
 400
 401         /*
 402          * Allow the write-enable status to change only while the
 403          * backing file is closed.
 404          */
 405         down_read(filesem);
 406         rc = _fsg_store_ro(curlun, ro);
 407         if (!rc)
 408                 rc = count;
 409         up_read(filesem);
 410
 411         return rc;
 412 }
 413 EXPORT_SYMBOL_GPL(fsg_store_ro);
 414
 415 ssize_t fsg_store_nofua(struct fsg_lun *curlun, const char *buf, size_t count)
 416 {
 417         bool            nofua;
 418         int             ret;
 419
 420         ret = strtobool(buf, &nofua);
 421         if (ret)
 422                 return ret;
 423
 424         /* Sync data when switching from async mode to sync */
 425         if (!nofua && curlun->nofua)
 426                 fsg_lun_fsync_sub(curlun);
 427
 428         curlun->nofua = nofua;
 429
 430         return count;
 431 }
 432 EXPORT_SYMBOL_GPL(fsg_store_nofua);
 433
 434 ssize_t fsg_store_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
 435                        const char *buf, size_t count)
 436 {
 437         int             rc = 0;
 438
 439         if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
 440                 LDBG(curlun, "eject attempt prevented\n");
 441                 return -EBUSY;                          /* "Door is locked" */
 442         }
 443
 444         /* Remove a trailing newline */
 445         if (count > 0 && buf[count-1] == '\n')
 446                 ((char *) buf)[count-1] = 0;            /* Ugh! */
 447
 448         /* Load new medium */
 449         down_write(filesem);
 450         if (count > 0 && buf[0]) {
 451                 /* fsg_lun_open() will close existing file if any. */
 452                 rc = fsg_lun_open(curlun, buf);
 453                 if (rc == 0)
 454                         curlun->unit_attention_data =
 455                                         SS_NOT_READY_TO_READY_TRANSITION;
 456         } else if (fsg_lun_is_open(curlun)) {
 457                 fsg_lun_close(curlun);
 458                 curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
 459         }
 460         up_write(filesem);
 461         return (rc < 0 ? rc : count);
 462 }
 463 EXPORT_SYMBOL_GPL(fsg_store_file);
 464
 465 ssize_t fsg_store_cdrom(struct fsg_lun *curlun, struct rw_semaphore *filesem,
 466                         const char *buf, size_t count)
 467 {
 468         bool            cdrom;
 469         int             ret;
 470
 471         ret = strtobool(buf, &cdrom);
 472         if (ret)
 473                 return ret;
 474
 475         down_read(filesem);
 476         ret = cdrom ? _fsg_store_ro(curlun, true) : 0;
 477
 478         if (!ret) {
 479                 curlun->cdrom = cdrom;
 480                 ret = count;
 481         }
 482         up_read(filesem);
 483
 484         return ret;
 485 }
 486 EXPORT_SYMBOL_GPL(fsg_store_cdrom);
 487
 488 ssize_t fsg_store_removable(struct fsg_lun *curlun, const char *buf,
 489                             size_t count)
 490 {
 491         bool            removable;
 492         int             ret;
 493
 494         ret = strtobool(buf, &removable);
 495         if (ret)
 496                 return ret;
 497
 498         curlun->removable = removable;
 499
 500         return count;
 501 }
 502 EXPORT_SYMBOL_GPL(fsg_store_removable);
 503
 504 MODULE_LICENSE("GPL");