drivers/usb/gadget/legacy/inode.c

   1 /*
   2  * inode.c -- user mode filesystem api for usb gadget controllers
   3  *
   4  * Copyright (C) 2003-2004 David Brownell
   5  * Copyright (C) 2003 Agilent Technologies
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13
  14 /* #define VERBOSE_DEBUG */
  15
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/fs.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/uts.h>
  21 #include <linux/wait.h>
  22 #include <linux/compiler.h>
  23 #include <asm/uaccess.h>
  24 #include <linux/sched.h>
  25 #include <linux/slab.h>
  26 #include <linux/poll.h>
  27 #include <linux/mmu_context.h>
  28 #include <linux/aio.h>
  29 #include <linux/uio.h>
  30
  31 #include <linux/device.h>
  32 #include <linux/moduleparam.h>
  33
  34 #include <linux/usb/gadgetfs.h>
  35 #include <linux/usb/gadget.h>
  36
  37
  38 /*
  39  * The gadgetfs API maps each endpoint to a file descriptor so that you
  40  * can use standard synchronous read/write calls for I/O.  There's some
  41  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  42  * drivers show how this works in practice.  You can also use AIO to
  43  * eliminate I/O gaps between requests, to help when streaming data.
  44  *
  45  * Key parts that must be USB-specific are protocols defining how the
  46  * read/write operations relate to the hardware state machines.  There
  47  * are two types of files.  One type is for the device, implementing ep0.
  48  * The other type is for each IN or OUT endpoint.  In both cases, the
  49  * user mode driver must configure the hardware before using it.
  50  *
  51  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  52  *   (by writing configuration and device descriptors).  Afterwards it
  53  *   may serve as a source of device events, used to handle all control
  54  *   requests other than basic enumeration.
  55  *
  56  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  57  *   called when each /dev/gadget/ep* file is configured (by writing
  58  *   endpoint descriptors).  Afterwards these files are used to write()
  59  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  60  *   direction" request is issued (like reading an IN endpoint).
  61  *
  62  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  63  * not possible on all hardware.  For example, precise fault handling with
  64  * respect to data left in endpoint fifos after aborted operations; or
  65  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  66  */
  67
  68 #define DRIVER_DESC     "USB Gadget filesystem"
  69 #define DRIVER_VERSION  "24 Aug 2004"
  70
  71 static const char driver_desc [] = DRIVER_DESC;
  72 static const char shortname [] = "gadgetfs";
  73
  74 MODULE_DESCRIPTION (DRIVER_DESC);
  75 MODULE_AUTHOR ("David Brownell");
  76 MODULE_LICENSE ("GPL");
  77
  78 static int ep_open(struct inode *, struct file *);
  79
  80
  81 /*----------------------------------------------------------------------*/
  82
  83 #define GADGETFS_MAGIC          0xaee71ee7
  84
  85 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  86 enum ep0_state {
  87         /* DISBLED is the initial state.
  88          */
  89         STATE_DEV_DISABLED = 0,
  90
  91         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  92          * ep0/device i/o modes and binding to the controller.  Driver
  93          * must always write descriptors to initialize the device, then
  94          * the device becomes UNCONNECTED until enumeration.
  95          */
  96         STATE_DEV_OPENED,
  97
  98         /* From then on, ep0 fd is in either of two basic modes:
  99          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
 100          * - SETUP: read/write will transfer control data and succeed;
 101          *   or if "wrong direction", performs protocol stall
 102          */
 103         STATE_DEV_UNCONNECTED,
 104         STATE_DEV_CONNECTED,
 105         STATE_DEV_SETUP,
 106
 107         /* UNBOUND means the driver closed ep0, so the device won't be
 108          * accessible again (DEV_DISABLED) until all fds are closed.
 109          */
 110         STATE_DEV_UNBOUND,
 111 };
 112
 113 /* enough for the whole queue: most events invalidate others */
 114 #define N_EVENT                 5
 115
 116 struct dev_data {
 117         spinlock_t                      lock;
 118         atomic_t                        count;
 119         enum ep0_state                  state;          /* P: lock */
 120         struct usb_gadgetfs_event       event [N_EVENT];
 121         unsigned                        ev_next;
 122         struct fasync_struct            *fasync;
 123         u8                              current_config;
 124
 125         /* drivers reading ep0 MUST handle control requests (SETUP)
 126          * reported that way; else the host will time out.
 127          */
 128         unsigned                        usermode_setup : 1,
 129                                         setup_in : 1,
 130                                         setup_can_stall : 1,
 131                                         setup_out_ready : 1,
 132                                         setup_out_error : 1,
 133                                         setup_abort : 1;
 134         unsigned                        setup_wLength;
 135
 136         /* the rest is basically write-once */
 137         struct usb_config_descriptor    *config, *hs_config;
 138         struct usb_device_descriptor    *dev;
 139         struct usb_request              *req;
 140         struct usb_gadget               *gadget;
 141         struct list_head                epfiles;
 142         void                            *buf;
 143         wait_queue_head_t               wait;
 144         struct super_block              *sb;
 145         struct dentry                   *dentry;
 146
 147         /* except this scratch i/o buffer for ep0 */
 148         u8                              rbuf [256];
 149 };
 150
 151 static inline void get_dev (struct dev_data *data)
 152 {
 153         atomic_inc (&data->count);
 154 }
 155
 156 static void put_dev (struct dev_data *data)
 157 {
 158         if (likely (!atomic_dec_and_test (&data->count)))
 159                 return;
 160         /* needs no more cleanup */
 161         BUG_ON (waitqueue_active (&data->wait));
 162         kfree (data);
 163 }
 164
 165 static struct dev_data *dev_new (void)
 166 {
 167         struct dev_data         *dev;
 168
 169         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 170         if (!dev)
 171                 return NULL;
 172         dev->state = STATE_DEV_DISABLED;
 173         atomic_set (&dev->count, 1);
 174         spin_lock_init (&dev->lock);
 175         INIT_LIST_HEAD (&dev->epfiles);
 176         init_waitqueue_head (&dev->wait);
 177         return dev;
 178 }
 179
 180 /*----------------------------------------------------------------------*/
 181
 182 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 183 enum ep_state {
 184         STATE_EP_DISABLED = 0,
 185         STATE_EP_READY,
 186         STATE_EP_ENABLED,
 187         STATE_EP_UNBOUND,
 188 };
 189
 190 struct ep_data {
 191         struct mutex                    lock;
 192         enum ep_state                   state;
 193         atomic_t                        count;
 194         struct dev_data                 *dev;
 195         /* must hold dev->lock before accessing ep or req */
 196         struct usb_ep                   *ep;
 197         struct usb_request              *req;
 198         ssize_t                         status;
 199         char                            name [16];
 200         struct usb_endpoint_descriptor  desc, hs_desc;
 201         struct list_head                epfiles;
 202         wait_queue_head_t               wait;
 203         struct dentry                   *dentry;
 204 };
 205
 206 static inline void get_ep (struct ep_data *data)
 207 {
 208         atomic_inc (&data->count);
 209 }
 210
 211 static void put_ep (struct ep_data *data)
 212 {
 213         if (likely (!atomic_dec_and_test (&data->count)))
 214                 return;
 215         put_dev (data->dev);
 216         /* needs no more cleanup */
 217         BUG_ON (!list_empty (&data->epfiles));
 218         BUG_ON (waitqueue_active (&data->wait));
 219         kfree (data);
 220 }
 221
 222 /*----------------------------------------------------------------------*/
 223
 224 /* most "how to use the hardware" policy choices are in userspace:
 225  * mapping endpoint roles (which the driver needs) to the capabilities
 226  * which the usb controller has.  most of those capabilities are exposed
 227  * implicitly, starting with the driver name and then endpoint names.
 228  */
 229
 230 static const char *CHIP;
 231
 232 /*----------------------------------------------------------------------*/
 233
 234 /* NOTE:  don't use dev_printk calls before binding to the gadget
 235  * at the end of ep0 configuration, or after unbind.
 236  */
 237
 238 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 239 #define xprintk(d,level,fmt,args...) \
 240         printk(level "%s: " fmt , shortname , ## args)
 241
 242 #ifdef DEBUG
 243 #define DBG(dev,fmt,args...) \
 244         xprintk(dev , KERN_DEBUG , fmt , ## args)
 245 #else
 246 #define DBG(dev,fmt,args...) \
 247         do { } while (0)
 248 #endif /* DEBUG */
 249
 250 #ifdef VERBOSE_DEBUG
 251 #define VDEBUG  DBG
 252 #else
 253 #define VDEBUG(dev,fmt,args...) \
 254         do { } while (0)
 255 #endif /* DEBUG */
 256
 257 #define ERROR(dev,fmt,args...) \
 258         xprintk(dev , KERN_ERR , fmt , ## args)
 259 #define INFO(dev,fmt,args...) \
 260         xprintk(dev , KERN_INFO , fmt , ## args)
 261
 262
 263 /*----------------------------------------------------------------------*/
 264
 265 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 266  *
 267  * After opening, configure non-control endpoints.  Then use normal
 268  * stream read() and write() requests; and maybe ioctl() to get more
 269  * precise FIFO status when recovering from cancellation.
 270  */
 271
 272 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 273 {
 274         struct ep_data  *epdata = ep->driver_data;
 275
 276         if (!req->context)
 277                 return;
 278         if (req->status)
 279                 epdata->status = req->status;
 280         else
 281                 epdata->status = req->actual;
 282         complete ((struct completion *)req->context);
 283 }
 284
 285 /* tasklock endpoint, returning when it's connected.
 286  * still need dev->lock to use epdata->ep.
 287  */
 288 static int
 289 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 290 {
 291         int     val;
 292
 293         if (f_flags & O_NONBLOCK) {
 294                 if (!mutex_trylock(&epdata->lock))
 295                         goto nonblock;
 296                 if (epdata->state != STATE_EP_ENABLED &&
 297                     (!is_write || epdata->state != STATE_EP_READY)) {
 298                         mutex_unlock(&epdata->lock);
 299 nonblock:
 300                         val = -EAGAIN;
 301                 } else
 302                         val = 0;
 303                 return val;
 304         }
 305
 306         val = mutex_lock_interruptible(&epdata->lock);
 307         if (val < 0)
 308                 return val;
 309
 310         switch (epdata->state) {
 311         case STATE_EP_ENABLED:
 312                 return 0;
 313         case STATE_EP_READY:                    /* not configured yet */
 314                 if (is_write)
 315                         return 0;
 316                 // FALLTHRU
 317         case STATE_EP_UNBOUND:                  /* clean disconnect */
 318                 break;
 319         // case STATE_EP_DISABLED:              /* "can't happen" */
 320         default:                                /* error! */
 321                 pr_debug ("%s: ep %p not available, state %d\n",
 322                                 shortname, epdata, epdata->state);
 323         }
 324         mutex_unlock(&epdata->lock);
 325         return -ENODEV;
 326 }
 327
 328 static ssize_t
 329 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 330 {
 331         DECLARE_COMPLETION_ONSTACK (done);
 332         int value;
 333
 334         spin_lock_irq (&epdata->dev->lock);
 335         if (likely (epdata->ep != NULL)) {
 336                 struct usb_request      *req = epdata->req;
 337
 338                 req->context = &done;
 339                 req->complete = epio_complete;
 340                 req->buf = buf;
 341                 req->length = len;
 342                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 343         } else
 344                 value = -ENODEV;
 345         spin_unlock_irq (&epdata->dev->lock);
 346
 347         if (likely (value == 0)) {
 348                 value = wait_event_interruptible (done.wait, done.done);
 349                 if (value != 0) {
 350                         spin_lock_irq (&epdata->dev->lock);
 351                         if (likely (epdata->ep != NULL)) {
 352                                 DBG (epdata->dev, "%s i/o interrupted\n",
 353                                                 epdata->name);
 354                                 usb_ep_dequeue (epdata->ep, epdata->req);
 355                                 spin_unlock_irq (&epdata->dev->lock);
 356
 357                                 wait_event (done.wait, done.done);
 358                                 if (epdata->status == -ECONNRESET)
 359                                         epdata->status = -EINTR;
 360                         } else {
 361                                 spin_unlock_irq (&epdata->dev->lock);
 362
 363                                 DBG (epdata->dev, "endpoint gone\n");
 364                                 epdata->status = -ENODEV;
 365                         }
 366                 }
 367                 return epdata->status;
 368         }
 369         return value;
 370 }
 371
 372 static int
 373 ep_release (struct inode *inode, struct file *fd)
 374 {
 375         struct ep_data          *data = fd->private_data;
 376         int value;
 377
 378         value = mutex_lock_interruptible(&data->lock);
 379         if (value < 0)
 380                 return value;
 381
 382         /* clean up if this can be reopened */
 383         if (data->state != STATE_EP_UNBOUND) {
 384                 data->state = STATE_EP_DISABLED;
 385                 data->desc.bDescriptorType = 0;
 386                 data->hs_desc.bDescriptorType = 0;
 387                 usb_ep_disable(data->ep);
 388         }
 389         mutex_unlock(&data->lock);
 390         put_ep (data);
 391         return 0;
 392 }
 393
 394 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 395 {
 396         struct ep_data          *data = fd->private_data;
 397         int                     status;
 398
 399         if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
 400                 return status;
 401
 402         spin_lock_irq (&data->dev->lock);
 403         if (likely (data->ep != NULL)) {
 404                 switch (code) {
 405                 case GADGETFS_FIFO_STATUS:
 406                         status = usb_ep_fifo_status (data->ep);
 407                         break;
 408                 case GADGETFS_FIFO_FLUSH:
 409                         usb_ep_fifo_flush (data->ep);
 410                         break;
 411                 case GADGETFS_CLEAR_HALT:
 412                         status = usb_ep_clear_halt (data->ep);
 413                         break;
 414                 default:
 415                         status = -ENOTTY;
 416                 }
 417         } else
 418                 status = -ENODEV;
 419         spin_unlock_irq (&data->dev->lock);
 420         mutex_unlock(&data->lock);
 421         return status;
 422 }
 423
 424 /*----------------------------------------------------------------------*/
 425
 426 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 427
 428 struct kiocb_priv {
 429         struct usb_request      *req;
 430         struct ep_data          *epdata;
 431         struct kiocb            *iocb;
 432         struct mm_struct        *mm;
 433         struct work_struct      work;
 434         void                    *buf;
 435         struct iov_iter         to;
 436         const void              *to_free;
 437         unsigned                actual;
 438 };
 439
 440 static int ep_aio_cancel(struct kiocb *iocb)
 441 {
 442         struct kiocb_priv       *priv = iocb->private;
 443         struct ep_data          *epdata;
 444         int                     value;
 445
 446         local_irq_disable();
 447         epdata = priv->epdata;
 448         // spin_lock(&epdata->dev->lock);
 449         if (likely(epdata && epdata->ep && priv->req))
 450                 value = usb_ep_dequeue (epdata->ep, priv->req);
 451         else
 452                 value = -EINVAL;
 453         // spin_unlock(&epdata->dev->lock);
 454         local_irq_enable();
 455
 456         return value;
 457 }
 458
 459 static void ep_user_copy_worker(struct work_struct *work)
 460 {
 461         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 462         struct mm_struct *mm = priv->mm;
 463         struct kiocb *iocb = priv->iocb;
 464         size_t ret;
 465
 466         use_mm(mm);
 467         ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
 468         unuse_mm(mm);
 469         if (!ret)
 470                 ret = -EFAULT;
 471
 472         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 473         iocb->ki_complete(iocb, ret, ret);
 474
 475         kfree(priv->buf);
 476         kfree(priv->to_free);
 477         kfree(priv);
 478 }
 479
 480 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 481 {
 482         struct kiocb            *iocb = req->context;
 483         struct kiocb_priv       *priv = iocb->private;
 484         struct ep_data          *epdata = priv->epdata;
 485
 486         /* lock against disconnect (and ideally, cancel) */
 487         spin_lock(&epdata->dev->lock);
 488         priv->req = NULL;
 489         priv->epdata = NULL;
 490
 491         /* if this was a write or a read returning no data then we
 492          * don't need to copy anything to userspace, so we can
 493          * complete the aio request immediately.
 494          */
 495         if (priv->to_free == NULL || unlikely(req->actual == 0)) {
 496                 kfree(req->buf);
 497                 kfree(priv->to_free);
 498                 kfree(priv);
 499                 iocb->private = NULL;
 500                 /* aio_complete() reports bytes-transferred _and_ faults */
 501
 502                 iocb->ki_complete(iocb, req->actual ? req->actual : req->status,
 503                                 req->status);
 504         } else {
 505                 /* ep_copy_to_user() won't report both; we hide some faults */
 506                 if (unlikely(0 != req->status))
 507                         DBG(epdata->dev, "%s fault %d len %d\n",
 508                                 ep->name, req->status, req->actual);
 509
 510                 priv->buf = req->buf;
 511                 priv->actual = req->actual;
 512                 INIT_WORK(&priv->work, ep_user_copy_worker);
 513                 schedule_work(&priv->work);
 514         }
 515         spin_unlock(&epdata->dev->lock);
 516
 517         usb_ep_free_request(ep, req);
 518         put_ep(epdata);
 519 }
 520
 521 static ssize_t ep_aio(struct kiocb *iocb,
 522                       struct kiocb_priv *priv,
 523                       struct ep_data *epdata,
 524                       char *buf,
 525                       size_t len)
 526 {
 527         struct usb_request *req;
 528         ssize_t value;
 529
 530         iocb->private = priv;
 531         priv->iocb = iocb;
 532
 533         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 534         get_ep(epdata);
 535         priv->epdata = epdata;
 536         priv->actual = 0;
 537         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 538
 539         /* each kiocb is coupled to one usb_request, but we can't
 540          * allocate or submit those if the host disconnected.
 541          */
 542         spin_lock_irq(&epdata->dev->lock);
 543         value = -ENODEV;
 544         if (unlikely(epdata->ep == NULL))
 545                 goto fail;
 546
 547         req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 548         value = -ENOMEM;
 549         if (unlikely(!req))
 550                 goto fail;
 551
 552         priv->req = req;
 553         req->buf = buf;
 554         req->length = len;
 555         req->complete = ep_aio_complete;
 556         req->context = iocb;
 557         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 558         if (unlikely(0 != value)) {
 559                 usb_ep_free_request(epdata->ep, req);
 560                 goto fail;
 561         }
 562         spin_unlock_irq(&epdata->dev->lock);
 563         return -EIOCBQUEUED;
 564
 565 fail:
 566         spin_unlock_irq(&epdata->dev->lock);
 567         kfree(priv->to_free);
 568         kfree(priv);
 569         put_ep(epdata);
 570         return value;
 571 }
 572
 573 static ssize_t
 574 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 575 {
 576         struct file *file = iocb->ki_filp;
 577         struct ep_data *epdata = file->private_data;
 578         size_t len = iov_iter_count(to);
 579         ssize_t value;
 580         char *buf;
 581
 582         if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
 583                 return value;
 584
 585         /* halt any endpoint by doing a "wrong direction" i/o call */
 586         if (usb_endpoint_dir_in(&epdata->desc)) {
 587                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 588                     !is_sync_kiocb(iocb)) {
 589                         mutex_unlock(&epdata->lock);
 590                         return -EINVAL;
 591                 }
 592                 DBG (epdata->dev, "%s halt\n", epdata->name);
 593                 spin_lock_irq(&epdata->dev->lock);
 594                 if (likely(epdata->ep != NULL))
 595                         usb_ep_set_halt(epdata->ep);
 596                 spin_unlock_irq(&epdata->dev->lock);
 597                 mutex_unlock(&epdata->lock);
 598                 return -EBADMSG;
 599         }
 600
 601         buf = kmalloc(len, GFP_KERNEL);
 602         if (unlikely(!buf)) {
 603                 mutex_unlock(&epdata->lock);
 604                 return -ENOMEM;
 605         }
 606         if (is_sync_kiocb(iocb)) {
 607                 value = ep_io(epdata, buf, len);
 608                 if (value >= 0 && copy_to_iter(buf, value, to))
 609                         value = -EFAULT;
 610         } else {
 611                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 612                 value = -ENOMEM;
 613                 if (!priv)
 614                         goto fail;
 615                 priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
 616                 if (!priv->to_free) {
 617                         kfree(priv);
 618                         goto fail;
 619                 }
 620                 value = ep_aio(iocb, priv, epdata, buf, len);
 621                 if (value == -EIOCBQUEUED)
 622                         buf = NULL;
 623         }
 624 fail:
 625         kfree(buf);
 626         mutex_unlock(&epdata->lock);
 627         return value;
 628 }
 629
 630 static ssize_t ep_config(struct ep_data *, const char *, size_t);
 631
 632 static ssize_t
 633 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 634 {
 635         struct file *file = iocb->ki_filp;
 636         struct ep_data *epdata = file->private_data;
 637         size_t len = iov_iter_count(from);
 638         bool configured;
 639         ssize_t value;
 640         char *buf;
 641
 642         if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
 643                 return value;
 644
 645         configured = epdata->state == STATE_EP_ENABLED;
 646
 647         /* halt any endpoint by doing a "wrong direction" i/o call */
 648         if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
 649                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 650                     !is_sync_kiocb(iocb)) {
 651                         mutex_unlock(&epdata->lock);
 652                         return -EINVAL;
 653                 }
 654                 DBG (epdata->dev, "%s halt\n", epdata->name);
 655                 spin_lock_irq(&epdata->dev->lock);
 656                 if (likely(epdata->ep != NULL))
 657                         usb_ep_set_halt(epdata->ep);
 658                 spin_unlock_irq(&epdata->dev->lock);
 659                 mutex_unlock(&epdata->lock);
 660                 return -EBADMSG;
 661         }
 662
 663         buf = kmalloc(len, GFP_KERNEL);
 664         if (unlikely(!buf)) {
 665                 mutex_unlock(&epdata->lock);
 666                 return -ENOMEM;
 667         }
 668
 669         if (unlikely(copy_from_iter(buf, len, from) != len)) {
 670                 value = -EFAULT;
 671                 goto out;
 672         }
 673
 674         if (unlikely(!configured)) {
 675                 value = ep_config(epdata, buf, len);
 676         } else if (is_sync_kiocb(iocb)) {
 677                 value = ep_io(epdata, buf, len);
 678         } else {
 679                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 680                 value = -ENOMEM;
 681                 if (priv) {
 682                         value = ep_aio(iocb, priv, epdata, buf, len);
 683                         if (value == -EIOCBQUEUED)
 684                                 buf = NULL;
 685                 }
 686         }
 687 out:
 688         kfree(buf);
 689         mutex_unlock(&epdata->lock);
 690         return value;
 691 }
 692
 693 /*----------------------------------------------------------------------*/
 694
 695 /* used after endpoint configuration */
 696 static const struct file_operations ep_io_operations = {
 697         .owner =        THIS_MODULE,
 698
 699         .open =         ep_open,
 700         .release =      ep_release,
 701         .llseek =       no_llseek,
 702         .unlocked_ioctl = ep_ioctl,
 703         .read_iter =    ep_read_iter,
 704         .write_iter =   ep_write_iter,
 705 };
 706
 707 /* ENDPOINT INITIALIZATION
 708  *
 709  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 710  *     status = write (fd, descriptors, sizeof descriptors)
 711  *
 712  * That write establishes the endpoint configuration, configuring
 713  * the controller to process bulk, interrupt, or isochronous transfers
 714  * at the right maxpacket size, and so on.
 715  *
 716  * The descriptors are message type 1, identified by a host order u32
 717  * at the beginning of what's written.  Descriptor order is: full/low
 718  * speed descriptor, then optional high speed descriptor.
 719  */
 720 static ssize_t
 721 ep_config (struct ep_data *data, const char *buf, size_t len)
 722 {
 723         struct usb_ep           *ep;
 724         u32                     tag;
 725         int                     value, length = len;
 726
 727         if (data->state != STATE_EP_READY) {
 728                 value = -EL2HLT;
 729                 goto fail;
 730         }
 731
 732         value = len;
 733         if (len < USB_DT_ENDPOINT_SIZE + 4)
 734                 goto fail0;
 735
 736         /* we might need to change message format someday */
 737         memcpy(&tag, buf, 4);
 738         if (tag != 1) {
 739                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 740                 goto fail0;
 741         }
 742         buf += 4;
 743         len -= 4;
 744
 745         /* NOTE:  audio endpoint extensions not accepted here;
 746          * just don't include the extra bytes.
 747          */
 748
 749         /* full/low speed descriptor, then high speed */
 750         memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
 751         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 752                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 753                 goto fail0;
 754         if (len != USB_DT_ENDPOINT_SIZE) {
 755                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 756                         goto fail0;
 757                 memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 758                         USB_DT_ENDPOINT_SIZE);
 759                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 760                                 || data->hs_desc.bDescriptorType
 761                                         != USB_DT_ENDPOINT) {
 762                         DBG(data->dev, "config %s, bad hs length or type\n",
 763                                         data->name);
 764                         goto fail0;
 765                 }
 766         }
 767
 768         spin_lock_irq (&data->dev->lock);
 769         if (data->dev->state == STATE_DEV_UNBOUND) {
 770                 value = -ENOENT;
 771                 goto gone;
 772         } else {
 773                 ep = data->ep;
 774                 if (ep == NULL) {
 775                         value = -ENODEV;
 776                         goto gone;
 777                 }
 778         }
 779         switch (data->dev->gadget->speed) {
 780         case USB_SPEED_LOW:
 781         case USB_SPEED_FULL:
 782                 ep->desc = &data->desc;
 783                 break;
 784         case USB_SPEED_HIGH:
 785                 /* fails if caller didn't provide that descriptor... */
 786                 ep->desc = &data->hs_desc;
 787                 break;
 788         default:
 789                 DBG(data->dev, "unconnected, %s init abandoned\n",
 790                                 data->name);
 791                 value = -EINVAL;
 792                 goto gone;
 793         }
 794         value = usb_ep_enable(ep);
 795         if (value == 0) {
 796                 data->state = STATE_EP_ENABLED;
 797                 value = length;
 798         }
 799 gone:
 800         spin_unlock_irq (&data->dev->lock);
 801         if (value < 0) {
 802 fail:
 803                 data->desc.bDescriptorType = 0;
 804                 data->hs_desc.bDescriptorType = 0;
 805         }
 806         return value;
 807 fail0:
 808         value = -EINVAL;
 809         goto fail;
 810 }
 811
 812 static int
 813 ep_open (struct inode *inode, struct file *fd)
 814 {
 815         struct ep_data          *data = inode->i_private;
 816         int                     value = -EBUSY;
 817
 818         if (mutex_lock_interruptible(&data->lock) != 0)
 819                 return -EINTR;
 820         spin_lock_irq (&data->dev->lock);
 821         if (data->dev->state == STATE_DEV_UNBOUND)
 822                 value = -ENOENT;
 823         else if (data->state == STATE_EP_DISABLED) {
 824                 value = 0;
 825                 data->state = STATE_EP_READY;
 826                 get_ep (data);
 827                 fd->private_data = data;
 828                 VDEBUG (data->dev, "%s ready\n", data->name);
 829         } else
 830                 DBG (data->dev, "%s state %d\n",
 831                         data->name, data->state);
 832         spin_unlock_irq (&data->dev->lock);
 833         mutex_unlock(&data->lock);
 834         return value;
 835 }
 836
 837 /*----------------------------------------------------------------------*/
 838
 839 /* EP0 IMPLEMENTATION can be partly in userspace.
 840  *
 841  * Drivers that use this facility receive various events, including
 842  * control requests the kernel doesn't handle.  Drivers that don't
 843  * use this facility may be too simple-minded for real applications.
 844  */
 845
 846 static inline void ep0_readable (struct dev_data *dev)
 847 {
 848         wake_up (&dev->wait);
 849         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 850 }
 851
 852 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 853 {
 854         struct dev_data         *dev = ep->driver_data;
 855
 856         if (req->buf != dev->rbuf) {
 857                 kfree(req->buf);
 858                 req->buf = dev->rbuf;
 859         }
 860         req->complete = epio_complete;
 861         dev->setup_out_ready = 0;
 862 }
 863
 864 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 865 {
 866         struct dev_data         *dev = ep->driver_data;
 867         unsigned long           flags;
 868         int                     free = 1;
 869
 870         /* for control OUT, data must still get to userspace */
 871         spin_lock_irqsave(&dev->lock, flags);
 872         if (!dev->setup_in) {
 873                 dev->setup_out_error = (req->status != 0);
 874                 if (!dev->setup_out_error)
 875                         free = 0;
 876                 dev->setup_out_ready = 1;
 877                 ep0_readable (dev);
 878         }
 879
 880         /* clean up as appropriate */
 881         if (free && req->buf != &dev->rbuf)
 882                 clean_req (ep, req);
 883         req->complete = epio_complete;
 884         spin_unlock_irqrestore(&dev->lock, flags);
 885 }
 886
 887 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 888 {
 889         struct dev_data *dev = ep->driver_data;
 890
 891         if (dev->setup_out_ready) {
 892                 DBG (dev, "ep0 request busy!\n");
 893                 return -EBUSY;
 894         }
 895         if (len > sizeof (dev->rbuf))
 896                 req->buf = kmalloc(len, GFP_ATOMIC);
 897         if (req->buf == NULL) {
 898                 req->buf = dev->rbuf;
 899                 return -ENOMEM;
 900         }
 901         req->complete = ep0_complete;
 902         req->length = len;
 903         req->zero = 0;
 904         return 0;
 905 }
 906
 907 static ssize_t
 908 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 909 {
 910         struct dev_data                 *dev = fd->private_data;
 911         ssize_t                         retval;
 912         enum ep0_state                  state;
 913
 914         spin_lock_irq (&dev->lock);
 915         if (dev->state <= STATE_DEV_OPENED) {
 916                 retval = -EINVAL;
 917                 goto done;
 918         }
 919
 920         /* report fd mode change before acting on it */
 921         if (dev->setup_abort) {
 922                 dev->setup_abort = 0;
 923                 retval = -EIDRM;
 924                 goto done;
 925         }
 926
 927         /* control DATA stage */
 928         if ((state = dev->state) == STATE_DEV_SETUP) {
 929
 930                 if (dev->setup_in) {            /* stall IN */
 931                         VDEBUG(dev, "ep0in stall\n");
 932                         (void) usb_ep_set_halt (dev->gadget->ep0);
 933                         retval = -EL2HLT;
 934                         dev->state = STATE_DEV_CONNECTED;
 935
 936                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
 937                         struct usb_ep           *ep = dev->gadget->ep0;
 938                         struct usb_request      *req = dev->req;
 939
 940                         if ((retval = setup_req (ep, req, 0)) == 0) {
 941                                 spin_unlock_irq (&dev->lock);
 942                                 retval = usb_ep_queue (ep, req, GFP_KERNEL);
 943                                 spin_lock_irq (&dev->lock);
 944                         }
 945                         dev->state = STATE_DEV_CONNECTED;
 946
 947                         /* assume that was SET_CONFIGURATION */
 948                         if (dev->current_config) {
 949                                 unsigned power;
 950
 951                                 if (gadget_is_dualspeed(dev->gadget)
 952                                                 && (dev->gadget->speed
 953                                                         == USB_SPEED_HIGH))
 954                                         power = dev->hs_config->bMaxPower;
 955                                 else
 956                                         power = dev->config->bMaxPower;
 957                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
 958                         }
 959
 960                 } else {                        /* collect OUT data */
 961                         if ((fd->f_flags & O_NONBLOCK) != 0
 962                                         && !dev->setup_out_ready) {
 963                                 retval = -EAGAIN;
 964                                 goto done;
 965                         }
 966                         spin_unlock_irq (&dev->lock);
 967                         retval = wait_event_interruptible (dev->wait,
 968                                         dev->setup_out_ready != 0);
 969
 970                         /* FIXME state could change from under us */
 971                         spin_lock_irq (&dev->lock);
 972                         if (retval)
 973                                 goto done;
 974
 975                         if (dev->state != STATE_DEV_SETUP) {
 976                                 retval = -ECANCELED;
 977                                 goto done;
 978                         }
 979                         dev->state = STATE_DEV_CONNECTED;
 980
 981                         if (dev->setup_out_error)
 982                                 retval = -EIO;
 983                         else {
 984                                 len = min (len, (size_t)dev->req->actual);
 985 // FIXME don't call this with the spinlock held ...
 986                                 if (copy_to_user (buf, dev->req->buf, len))
 987                                         retval = -EFAULT;
 988                                 else
 989                                         retval = len;
 990                                 clean_req (dev->gadget->ep0, dev->req);
 991                                 /* NOTE userspace can't yet choose to stall */
 992                         }
 993                 }
 994                 goto done;
 995         }
 996
 997         /* else normal: return event data */
 998         if (len < sizeof dev->event [0]) {
 999                 retval = -EINVAL;
1000                 goto done;
1001         }
1002         len -= len % sizeof (struct usb_gadgetfs_event);
1003         dev->usermode_setup = 1;
1004
1005 scan:
1006         /* return queued events right away */
1007         if (dev->ev_next != 0) {
1008                 unsigned                i, n;
1009
1010                 n = len / sizeof (struct usb_gadgetfs_event);
1011                 if (dev->ev_next < n)
1012                         n = dev->ev_next;
1013
1014                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1015                 for (i = 0; i < n; i++) {
1016                         if (dev->event [i].type == GADGETFS_SETUP) {
1017                                 dev->state = STATE_DEV_SETUP;
1018                                 n = i + 1;
1019                                 break;
1020                         }
1021                 }
1022                 spin_unlock_irq (&dev->lock);
1023                 len = n * sizeof (struct usb_gadgetfs_event);
1024                 if (copy_to_user (buf, &dev->event, len))
1025                         retval = -EFAULT;
1026                 else
1027                         retval = len;
1028                 if (len > 0) {
1029                         /* NOTE this doesn't guard against broken drivers;
1030                          * concurrent ep0 readers may lose events.
1031                          */
1032                         spin_lock_irq (&dev->lock);
1033                         if (dev->ev_next > n) {
1034                                 memmove(&dev->event[0], &dev->event[n],
1035                                         sizeof (struct usb_gadgetfs_event)
1036                                                 * (dev->ev_next - n));
1037                         }
1038                         dev->ev_next -= n;
1039                         spin_unlock_irq (&dev->lock);
1040                 }
1041                 return retval;
1042         }
1043         if (fd->f_flags & O_NONBLOCK) {
1044                 retval = -EAGAIN;
1045                 goto done;
1046         }
1047
1048         switch (state) {
1049         default:
1050                 DBG (dev, "fail %s, state %d\n", __func__, state);
1051                 retval = -ESRCH;
1052                 break;
1053         case STATE_DEV_UNCONNECTED:
1054         case STATE_DEV_CONNECTED:
1055                 spin_unlock_irq (&dev->lock);
1056                 DBG (dev, "%s wait\n", __func__);
1057
1058                 /* wait for events */
1059                 retval = wait_event_interruptible (dev->wait,
1060                                 dev->ev_next != 0);
1061                 if (retval < 0)
1062                         return retval;
1063                 spin_lock_irq (&dev->lock);
1064                 goto scan;
1065         }
1066
1067 done:
1068         spin_unlock_irq (&dev->lock);
1069         return retval;
1070 }
1071
1072 static struct usb_gadgetfs_event *
1073 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1074 {
1075         struct usb_gadgetfs_event       *event;
1076         unsigned                        i;
1077
1078         switch (type) {
1079         /* these events purge the queue */
1080         case GADGETFS_DISCONNECT:
1081                 if (dev->state == STATE_DEV_SETUP)
1082                         dev->setup_abort = 1;
1083                 // FALL THROUGH
1084         case GADGETFS_CONNECT:
1085                 dev->ev_next = 0;
1086                 break;
1087         case GADGETFS_SETUP:            /* previous request timed out */
1088         case GADGETFS_SUSPEND:          /* same effect */
1089                 /* these events can't be repeated */
1090                 for (i = 0; i != dev->ev_next; i++) {
1091                         if (dev->event [i].type != type)
1092                                 continue;
1093                         DBG(dev, "discard old event[%d] %d\n", i, type);
1094                         dev->ev_next--;
1095                         if (i == dev->ev_next)
1096                                 break;
1097                         /* indices start at zero, for simplicity */
1098                         memmove (&dev->event [i], &dev->event [i + 1],
1099                                 sizeof (struct usb_gadgetfs_event)
1100                                         * (dev->ev_next - i));
1101                 }
1102                 break;
1103         default:
1104                 BUG ();
1105         }
1106         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1107         event = &dev->event [dev->ev_next++];
1108         BUG_ON (dev->ev_next > N_EVENT);
1109         memset (event, 0, sizeof *event);
1110         event->type = type;
1111         return event;
1112 }
1113
1114 static ssize_t
1115 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1116 {
1117         struct dev_data         *dev = fd->private_data;
1118         ssize_t                 retval = -ESRCH;
1119
1120         /* report fd mode change before acting on it */
1121         if (dev->setup_abort) {
1122                 dev->setup_abort = 0;
1123                 retval = -EIDRM;
1124
1125         /* data and/or status stage for control request */
1126         } else if (dev->state == STATE_DEV_SETUP) {
1127
1128                 len = min_t(size_t, len, dev->setup_wLength);
1129                 if (dev->setup_in) {
1130                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1131                         if (retval == 0) {
1132                                 dev->state = STATE_DEV_CONNECTED;
1133                                 spin_unlock_irq (&dev->lock);
1134                                 if (copy_from_user (dev->req->buf, buf, len))
1135                                         retval = -EFAULT;
1136                                 else {
1137                                         if (len < dev->setup_wLength)
1138                                                 dev->req->zero = 1;
1139                                         retval = usb_ep_queue (
1140                                                 dev->gadget->ep0, dev->req,
1141                                                 GFP_KERNEL);
1142                                 }
1143                                 if (retval < 0) {
1144                                         spin_lock_irq (&dev->lock);
1145                                         clean_req (dev->gadget->ep0, dev->req);
1146                                         spin_unlock_irq (&dev->lock);
1147                                 } else
1148                                         retval = len;
1149
1150                                 return retval;
1151                         }
1152
1153                 /* can stall some OUT transfers */
1154                 } else if (dev->setup_can_stall) {
1155                         VDEBUG(dev, "ep0out stall\n");
1156                         (void) usb_ep_set_halt (dev->gadget->ep0);
1157                         retval = -EL2HLT;
1158                         dev->state = STATE_DEV_CONNECTED;
1159                 } else {
1160                         DBG(dev, "bogus ep0out stall!\n");
1161                 }
1162         } else
1163                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1164
1165         return retval;
1166 }
1167
1168 static int
1169 ep0_fasync (int f, struct file *fd, int on)
1170 {
1171         struct dev_data         *dev = fd->private_data;
1172         // caller must F_SETOWN before signal delivery happens
1173         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1174         return fasync_helper (f, fd, on, &dev->fasync);
1175 }
1176
1177 static struct usb_gadget_driver gadgetfs_driver;
1178
1179 static int
1180 dev_release (struct inode *inode, struct file *fd)
1181 {
1182         struct dev_data         *dev = fd->private_data;
1183
1184         /* closing ep0 === shutdown all */
1185
1186         usb_gadget_unregister_driver (&gadgetfs_driver);
1187
1188         /* at this point "good" hardware has disconnected the
1189          * device from USB; the host won't see it any more.
1190          * alternatively, all host requests will time out.
1191          */
1192
1193         kfree (dev->buf);
1194         dev->buf = NULL;
1195
1196         /* other endpoints were all decoupled from this device */
1197         spin_lock_irq(&dev->lock);
1198         dev->state = STATE_DEV_DISABLED;
1199         spin_unlock_irq(&dev->lock);
1200
1201         put_dev (dev);
1202         return 0;
1203 }
1204
1205 static unsigned int
1206 ep0_poll (struct file *fd, poll_table *wait)
1207 {
1208        struct dev_data         *dev = fd->private_data;
1209        int                     mask = 0;
1210
1211         if (dev->state <= STATE_DEV_OPENED)
1212                 return DEFAULT_POLLMASK;
1213
1214        poll_wait(fd, &dev->wait, wait);
1215
1216        spin_lock_irq (&dev->lock);
1217
1218        /* report fd mode change before acting on it */
1219        if (dev->setup_abort) {
1220                dev->setup_abort = 0;
1221                mask = POLLHUP;
1222                goto out;
1223        }
1224
1225        if (dev->state == STATE_DEV_SETUP) {
1226                if (dev->setup_in || dev->setup_can_stall)
1227                        mask = POLLOUT;
1228        } else {
1229                if (dev->ev_next != 0)
1230                        mask = POLLIN;
1231        }
1232 out:
1233        spin_unlock_irq(&dev->lock);
1234        return mask;
1235 }
1236
1237 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1238 {
1239         struct dev_data         *dev = fd->private_data;
1240         struct usb_gadget       *gadget = dev->gadget;
1241         long ret = -ENOTTY;
1242
1243         if (gadget->ops->ioctl)
1244                 ret = gadget->ops->ioctl (gadget, code, value);
1245
1246         return ret;
1247 }
1248
1249 /*----------------------------------------------------------------------*/
1250
1251 /* The in-kernel gadget driver handles most ep0 issues, in particular
1252  * enumerating the single configuration (as provided from user space).
1253  *
1254  * Unrecognized ep0 requests may be handled in user space.
1255  */
1256
1257 static void make_qualifier (struct dev_data *dev)
1258 {
1259         struct usb_qualifier_descriptor         qual;
1260         struct usb_device_descriptor            *desc;
1261
1262         qual.bLength = sizeof qual;
1263         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1264         qual.bcdUSB = cpu_to_le16 (0x0200);
1265
1266         desc = dev->dev;
1267         qual.bDeviceClass = desc->bDeviceClass;
1268         qual.bDeviceSubClass = desc->bDeviceSubClass;
1269         qual.bDeviceProtocol = desc->bDeviceProtocol;
1270
1271         /* assumes ep0 uses the same value for both speeds ... */
1272         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1273
1274         qual.bNumConfigurations = 1;
1275         qual.bRESERVED = 0;
1276
1277         memcpy (dev->rbuf, &qual, sizeof qual);
1278 }
1279
1280 static int
1281 config_buf (struct dev_data *dev, u8 type, unsigned index)
1282 {
1283         int             len;
1284         int             hs = 0;
1285
1286         /* only one configuration */
1287         if (index > 0)
1288                 return -EINVAL;
1289
1290         if (gadget_is_dualspeed(dev->gadget)) {
1291                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1292                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1293                         hs = !hs;
1294         }
1295         if (hs) {
1296                 dev->req->buf = dev->hs_config;
1297                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1298         } else {
1299                 dev->req->buf = dev->config;
1300                 len = le16_to_cpu(dev->config->wTotalLength);
1301         }
1302         ((u8 *)dev->req->buf) [1] = type;
1303         return len;
1304 }
1305
1306 static int
1307 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1308 {
1309         struct dev_data                 *dev = get_gadget_data (gadget);
1310         struct usb_request              *req = dev->req;
1311         int                             value = -EOPNOTSUPP;
1312         struct usb_gadgetfs_event       *event;
1313         u16                             w_value = le16_to_cpu(ctrl->wValue);
1314         u16                             w_length = le16_to_cpu(ctrl->wLength);
1315
1316         spin_lock (&dev->lock);
1317         dev->setup_abort = 0;
1318         if (dev->state == STATE_DEV_UNCONNECTED) {
1319                 if (gadget_is_dualspeed(gadget)
1320                                 && gadget->speed == USB_SPEED_HIGH
1321                                 && dev->hs_config == NULL) {
1322                         spin_unlock(&dev->lock);
1323                         ERROR (dev, "no high speed config??\n");
1324                         return -EINVAL;
1325                 }
1326
1327                 dev->state = STATE_DEV_CONNECTED;
1328
1329                 INFO (dev, "connected\n");
1330                 event = next_event (dev, GADGETFS_CONNECT);
1331                 event->u.speed = gadget->speed;
1332                 ep0_readable (dev);
1333
1334         /* host may have given up waiting for response.  we can miss control
1335          * requests handled lower down (device/endpoint status and features);
1336          * then ep0_{read,write} will report the wrong status. controller
1337          * driver will have aborted pending i/o.
1338          */
1339         } else if (dev->state == STATE_DEV_SETUP)
1340                 dev->setup_abort = 1;
1341
1342         req->buf = dev->rbuf;
1343         req->context = NULL;
1344         value = -EOPNOTSUPP;
1345         switch (ctrl->bRequest) {
1346
1347         case USB_REQ_GET_DESCRIPTOR:
1348                 if (ctrl->bRequestType != USB_DIR_IN)
1349                         goto unrecognized;
1350                 switch (w_value >> 8) {
1351
1352                 case USB_DT_DEVICE:
1353                         value = min (w_length, (u16) sizeof *dev->dev);
1354                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1355                         req->buf = dev->dev;
1356                         break;
1357                 case USB_DT_DEVICE_QUALIFIER:
1358                         if (!dev->hs_config)
1359                                 break;
1360                         value = min (w_length, (u16)
1361                                 sizeof (struct usb_qualifier_descriptor));
1362                         make_qualifier (dev);
1363                         break;
1364                 case USB_DT_OTHER_SPEED_CONFIG:
1365                         // FALLTHROUGH
1366                 case USB_DT_CONFIG:
1367                         value = config_buf (dev,
1368                                         w_value >> 8,
1369                                         w_value & 0xff);
1370                         if (value >= 0)
1371                                 value = min (w_length, (u16) value);
1372                         break;
1373                 case USB_DT_STRING:
1374                         goto unrecognized;
1375
1376                 default:                // all others are errors
1377                         break;
1378                 }
1379                 break;
1380
1381         /* currently one config, two speeds */
1382         case USB_REQ_SET_CONFIGURATION:
1383                 if (ctrl->bRequestType != 0)
1384                         goto unrecognized;
1385                 if (0 == (u8) w_value) {
1386                         value = 0;
1387                         dev->current_config = 0;
1388                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1389                         // user mode expected to disable endpoints
1390                 } else {
1391                         u8      config, power;
1392
1393                         if (gadget_is_dualspeed(gadget)
1394                                         && gadget->speed == USB_SPEED_HIGH) {
1395                                 config = dev->hs_config->bConfigurationValue;
1396                                 power = dev->hs_config->bMaxPower;
1397                         } else {
1398                                 config = dev->config->bConfigurationValue;
1399                                 power = dev->config->bMaxPower;
1400                         }
1401
1402                         if (config == (u8) w_value) {
1403                                 value = 0;
1404                                 dev->current_config = config;
1405                                 usb_gadget_vbus_draw(gadget, 2 * power);
1406                         }
1407                 }
1408
1409                 /* report SET_CONFIGURATION like any other control request,
1410                  * except that usermode may not stall this.  the next
1411                  * request mustn't be allowed start until this finishes:
1412                  * endpoints and threads set up, etc.
1413                  *
1414                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1415                  * has bad/racey automagic that prevents synchronizing here.
1416                  * even kernel mode drivers often miss them.
1417                  */
1418                 if (value == 0) {
1419                         INFO (dev, "configuration #%d\n", dev->current_config);
1420                         usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1421                         if (dev->usermode_setup) {
1422                                 dev->setup_can_stall = 0;
1423                                 goto delegate;
1424                         }
1425                 }
1426                 break;
1427
1428 #ifndef CONFIG_USB_PXA25X
1429         /* PXA automagically handles this request too */
1430         case USB_REQ_GET_CONFIGURATION:
1431                 if (ctrl->bRequestType != 0x80)
1432                         goto unrecognized;
1433                 *(u8 *)req->buf = dev->current_config;
1434                 value = min (w_length, (u16) 1);
1435                 break;
1436 #endif
1437
1438         default:
1439 unrecognized:
1440                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1441                         dev->usermode_setup ? "delegate" : "fail",
1442                         ctrl->bRequestType, ctrl->bRequest,
1443                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1444
1445                 /* if there's an ep0 reader, don't stall */
1446                 if (dev->usermode_setup) {
1447                         dev->setup_can_stall = 1;
1448 delegate:
1449                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1450                                                 ? 1 : 0;
1451                         dev->setup_wLength = w_length;
1452                         dev->setup_out_ready = 0;
1453                         dev->setup_out_error = 0;
1454                         value = 0;
1455
1456                         /* read DATA stage for OUT right away */
1457                         if (unlikely (!dev->setup_in && w_length)) {
1458                                 value = setup_req (gadget->ep0, dev->req,
1459                                                         w_length);
1460                                 if (value < 0)
1461                                         break;
1462
1463                                 spin_unlock (&dev->lock);
1464                                 value = usb_ep_queue (gadget->ep0, dev->req,
1465                                                         GFP_KERNEL);
1466                                 spin_lock (&dev->lock);
1467                                 if (value < 0) {
1468                                         clean_req (gadget->ep0, dev->req);
1469                                         break;
1470                                 }
1471
1472                                 /* we can't currently stall these */
1473                                 dev->setup_can_stall = 0;
1474                         }
1475
1476                         /* state changes when reader collects event */
1477                         event = next_event (dev, GADGETFS_SETUP);
1478                         event->u.setup = *ctrl;
1479                         ep0_readable (dev);
1480                         spin_unlock (&dev->lock);
1481                         return 0;
1482                 }
1483         }
1484
1485         /* proceed with data transfer and status phases? */
1486         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1487                 req->length = value;
1488                 req->zero = value < w_length;
1489
1490                 spin_unlock (&dev->lock);
1491                 value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1492                 if (value < 0) {
1493                         DBG (dev, "ep_queue --> %d\n", value);
1494                         req->status = 0;
1495                 }
1496                 return value;
1497         }
1498
1499         /* device stalls when value < 0 */
1500         spin_unlock (&dev->lock);
1501         return value;
1502 }
1503
1504 static void destroy_ep_files (struct dev_data *dev)
1505 {
1506         DBG (dev, "%s %d\n", __func__, dev->state);
1507
1508         /* dev->state must prevent interference */
1509         spin_lock_irq (&dev->lock);
1510         while (!list_empty(&dev->epfiles)) {
1511                 struct ep_data  *ep;
1512                 struct inode    *parent;
1513                 struct dentry   *dentry;
1514
1515                 /* break link to FS */
1516                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1517                 list_del_init (&ep->epfiles);
1518                 dentry = ep->dentry;
1519                 ep->dentry = NULL;
1520                 parent = d_inode(dentry->d_parent);
1521
1522                 /* break link to controller */
1523                 if (ep->state == STATE_EP_ENABLED)
1524                         (void) usb_ep_disable (ep->ep);
1525                 ep->state = STATE_EP_UNBOUND;
1526                 usb_ep_free_request (ep->ep, ep->req);
1527                 ep->ep = NULL;
1528                 wake_up (&ep->wait);
1529                 put_ep (ep);
1530
1531                 spin_unlock_irq (&dev->lock);
1532
1533                 /* break link to dcache */
1534                 mutex_lock (&parent->i_mutex);
1535                 d_delete (dentry);
1536                 dput (dentry);
1537                 mutex_unlock (&parent->i_mutex);
1538
1539                 spin_lock_irq (&dev->lock);
1540         }
1541         spin_unlock_irq (&dev->lock);
1542 }
1543
1544
1545 static struct dentry *
1546 gadgetfs_create_file (struct super_block *sb, char const *name,
1547                 void *data, const struct file_operations *fops);
1548
1549 static int activate_ep_files (struct dev_data *dev)
1550 {
1551         struct usb_ep   *ep;
1552         struct ep_data  *data;
1553
1554         gadget_for_each_ep (ep, dev->gadget) {
1555
1556                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1557                 if (!data)
1558                         goto enomem0;
1559                 data->state = STATE_EP_DISABLED;
1560                 mutex_init(&data->lock);
1561                 init_waitqueue_head (&data->wait);
1562
1563                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1564                 atomic_set (&data->count, 1);
1565                 data->dev = dev;
1566                 get_dev (dev);
1567
1568                 data->ep = ep;
1569                 ep->driver_data = data;
1570
1571                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1572                 if (!data->req)
1573                         goto enomem1;
1574
1575                 data->dentry = gadgetfs_create_file (dev->sb, data->name,
1576                                 data, &ep_io_operations);
1577                 if (!data->dentry)
1578                         goto enomem2;
1579                 list_add_tail (&data->epfiles, &dev->epfiles);
1580         }
1581         return 0;
1582
1583 enomem2:
1584         usb_ep_free_request (ep, data->req);
1585 enomem1:
1586         put_dev (dev);
1587         kfree (data);
1588 enomem0:
1589         DBG (dev, "%s enomem\n", __func__);
1590         destroy_ep_files (dev);
1591         return -ENOMEM;
1592 }
1593
1594 static void
1595 gadgetfs_unbind (struct usb_gadget *gadget)
1596 {
1597         struct dev_data         *dev = get_gadget_data (gadget);
1598
1599         DBG (dev, "%s\n", __func__);
1600
1601         spin_lock_irq (&dev->lock);
1602         dev->state = STATE_DEV_UNBOUND;
1603         spin_unlock_irq (&dev->lock);
1604
1605         destroy_ep_files (dev);
1606         gadget->ep0->driver_data = NULL;
1607         set_gadget_data (gadget, NULL);
1608
1609         /* we've already been disconnected ... no i/o is active */
1610         if (dev->req)
1611                 usb_ep_free_request (gadget->ep0, dev->req);
1612         DBG (dev, "%s done\n", __func__);
1613         put_dev (dev);
1614 }
1615
1616 static struct dev_data          *the_device;
1617
1618 static int gadgetfs_bind(struct usb_gadget *gadget,
1619                 struct usb_gadget_driver *driver)
1620 {
1621         struct dev_data         *dev = the_device;
1622
1623         if (!dev)
1624                 return -ESRCH;
1625         if (0 != strcmp (CHIP, gadget->name)) {
1626                 pr_err("%s expected %s controller not %s\n",
1627                         shortname, CHIP, gadget->name);
1628                 return -ENODEV;
1629         }
1630
1631         set_gadget_data (gadget, dev);
1632         dev->gadget = gadget;
1633         gadget->ep0->driver_data = dev;
1634
1635         /* preallocate control response and buffer */
1636         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1637         if (!dev->req)
1638                 goto enomem;
1639         dev->req->context = NULL;
1640         dev->req->complete = epio_complete;
1641
1642         if (activate_ep_files (dev) < 0)
1643                 goto enomem;
1644
1645         INFO (dev, "bound to %s driver\n", gadget->name);
1646         spin_lock_irq(&dev->lock);
1647         dev->state = STATE_DEV_UNCONNECTED;
1648         spin_unlock_irq(&dev->lock);
1649         get_dev (dev);
1650         return 0;
1651
1652 enomem:
1653         gadgetfs_unbind (gadget);
1654         return -ENOMEM;
1655 }
1656
1657 static void
1658 gadgetfs_disconnect (struct usb_gadget *gadget)
1659 {
1660         struct dev_data         *dev = get_gadget_data (gadget);
1661         unsigned long           flags;
1662
1663         spin_lock_irqsave (&dev->lock, flags);
1664         if (dev->state == STATE_DEV_UNCONNECTED)
1665                 goto exit;
1666         dev->state = STATE_DEV_UNCONNECTED;
1667
1668         INFO (dev, "disconnected\n");
1669         next_event (dev, GADGETFS_DISCONNECT);
1670         ep0_readable (dev);
1671 exit:
1672         spin_unlock_irqrestore (&dev->lock, flags);
1673 }
1674
1675 static void
1676 gadgetfs_suspend (struct usb_gadget *gadget)
1677 {
1678         struct dev_data         *dev = get_gadget_data (gadget);
1679
1680         INFO (dev, "suspended from state %d\n", dev->state);
1681         spin_lock (&dev->lock);
1682         switch (dev->state) {
1683         case STATE_DEV_SETUP:           // VERY odd... host died??
1684         case STATE_DEV_CONNECTED:
1685         case STATE_DEV_UNCONNECTED:
1686                 next_event (dev, GADGETFS_SUSPEND);
1687                 ep0_readable (dev);
1688                 /* FALLTHROUGH */
1689         default:
1690                 break;
1691         }
1692         spin_unlock (&dev->lock);
1693 }
1694
1695 static struct usb_gadget_driver gadgetfs_driver = {
1696         .function       = (char *) driver_desc,
1697         .bind           = gadgetfs_bind,
1698         .unbind         = gadgetfs_unbind,
1699         .setup          = gadgetfs_setup,
1700         .reset          = gadgetfs_disconnect,
1701         .disconnect     = gadgetfs_disconnect,
1702         .suspend        = gadgetfs_suspend,
1703
1704         .driver = {
1705                 .name           = (char *) shortname,
1706         },
1707 };
1708
1709 /*----------------------------------------------------------------------*/
1710
1711 static void gadgetfs_nop(struct usb_gadget *arg) { }
1712
1713 static int gadgetfs_probe(struct usb_gadget *gadget,
1714                 struct usb_gadget_driver *driver)
1715 {
1716         CHIP = gadget->name;
1717         return -EISNAM;
1718 }
1719
1720 static struct usb_gadget_driver probe_driver = {
1721         .max_speed      = USB_SPEED_HIGH,
1722         .bind           = gadgetfs_probe,
1723         .unbind         = gadgetfs_nop,
1724         .setup          = (void *)gadgetfs_nop,
1725         .disconnect     = gadgetfs_nop,
1726         .driver = {
1727                 .name           = "nop",
1728         },
1729 };
1730
1731
1732 /* DEVICE INITIALIZATION
1733  *
1734  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1735  *     status = write (fd, descriptors, sizeof descriptors)
1736  *
1737  * That write establishes the device configuration, so the kernel can
1738  * bind to the controller ... guaranteeing it can handle enumeration
1739  * at all necessary speeds.  Descriptor order is:
1740  *
1741  * . message tag (u32, host order) ... for now, must be zero; it
1742  *      would change to support features like multi-config devices
1743  * . full/low speed config ... all wTotalLength bytes (with interface,
1744  *      class, altsetting, endpoint, and other descriptors)
1745  * . high speed config ... all descriptors, for high speed operation;
1746  *      this one's optional except for high-speed hardware
1747  * . device descriptor
1748  *
1749  * Endpoints are not yet enabled. Drivers must wait until device
1750  * configuration and interface altsetting changes create
1751  * the need to configure (or unconfigure) them.
1752  *
1753  * After initialization, the device stays active for as long as that
1754  * $CHIP file is open.  Events must then be read from that descriptor,
1755  * such as configuration notifications.
1756  */
1757
1758 static int is_valid_config(struct usb_config_descriptor *config,
1759                 unsigned int total)
1760 {
1761         return config->bDescriptorType == USB_DT_CONFIG
1762                 && config->bLength == USB_DT_CONFIG_SIZE
1763                 && total >= USB_DT_CONFIG_SIZE
1764                 && config->bConfigurationValue != 0
1765                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1766                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1767         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1768         /* FIXME check lengths: walk to end */
1769 }
1770
1771 static ssize_t
1772 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1773 {
1774         struct dev_data         *dev = fd->private_data;
1775         ssize_t                 value = len, length = len;
1776         unsigned                total;
1777         u32                     tag;
1778         char                    *kbuf;
1779
1780         spin_lock_irq(&dev->lock);
1781         if (dev->state > STATE_DEV_OPENED) {
1782                 value = ep0_write(fd, buf, len, ptr);
1783                 spin_unlock_irq(&dev->lock);
1784                 return value;
1785         }
1786         spin_unlock_irq(&dev->lock);
1787
1788         if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1789             (len > PAGE_SIZE * 4))
1790                 return -EINVAL;
1791
1792         /* we might need to change message format someday */
1793         if (copy_from_user (&tag, buf, 4))
1794                 return -EFAULT;
1795         if (tag != 0)
1796                 return -EINVAL;
1797         buf += 4;
1798         length -= 4;
1799
1800         kbuf = memdup_user(buf, length);
1801         if (IS_ERR(kbuf))
1802                 return PTR_ERR(kbuf);
1803
1804         spin_lock_irq (&dev->lock);
1805         value = -EINVAL;
1806         if (dev->buf)
1807                 goto fail;
1808         dev->buf = kbuf;
1809
1810         /* full or low speed config */
1811         dev->config = (void *) kbuf;
1812         total = le16_to_cpu(dev->config->wTotalLength);
1813         if (!is_valid_config(dev->config, total) ||
1814                         total > length - USB_DT_DEVICE_SIZE)
1815                 goto fail;
1816         kbuf += total;
1817         length -= total;
1818
1819         /* optional high speed config */
1820         if (kbuf [1] == USB_DT_CONFIG) {
1821                 dev->hs_config = (void *) kbuf;
1822                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1823                 if (!is_valid_config(dev->hs_config, total) ||
1824                                 total > length - USB_DT_DEVICE_SIZE)
1825                         goto fail;
1826                 kbuf += total;
1827                 length -= total;
1828         } else {
1829                 dev->hs_config = NULL;
1830         }
1831
1832         /* could support multiple configs, using another encoding! */
1833
1834         /* device descriptor (tweaked for paranoia) */
1835         if (length != USB_DT_DEVICE_SIZE)
1836                 goto fail;
1837         dev->dev = (void *)kbuf;
1838         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1839                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1840                         || dev->dev->bNumConfigurations != 1)
1841                 goto fail;
1842         dev->dev->bNumConfigurations = 1;
1843         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1844
1845         /* triggers gadgetfs_bind(); then we can enumerate. */
1846         spin_unlock_irq (&dev->lock);
1847         if (dev->hs_config)
1848                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1849         else
1850                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1851
1852         value = usb_gadget_probe_driver(&gadgetfs_driver);
1853         if (value != 0) {
1854                 kfree (dev->buf);
1855                 dev->buf = NULL;
1856         } else {
1857                 /* at this point "good" hardware has for the first time
1858                  * let the USB the host see us.  alternatively, if users
1859                  * unplug/replug that will clear all the error state.
1860                  *
1861                  * note:  everything running before here was guaranteed
1862                  * to choke driver model style diagnostics.  from here
1863                  * on, they can work ... except in cleanup paths that
1864                  * kick in after the ep0 descriptor is closed.
1865                  */
1866                 value = len;
1867         }
1868         return value;
1869
1870 fail:
1871         spin_unlock_irq (&dev->lock);
1872         pr_debug ("%s: %s fail %Zd, %p\n", shortname, __func__, value, dev);
1873         kfree (dev->buf);
1874         dev->buf = NULL;
1875         return value;
1876 }
1877
1878 static int
1879 dev_open (struct inode *inode, struct file *fd)
1880 {
1881         struct dev_data         *dev = inode->i_private;
1882         int                     value = -EBUSY;
1883
1884         spin_lock_irq(&dev->lock);
1885         if (dev->state == STATE_DEV_DISABLED) {
1886                 dev->ev_next = 0;
1887                 dev->state = STATE_DEV_OPENED;
1888                 fd->private_data = dev;
1889                 get_dev (dev);
1890                 value = 0;
1891         }
1892         spin_unlock_irq(&dev->lock);
1893         return value;
1894 }
1895
1896 static const struct file_operations ep0_operations = {
1897         .llseek =       no_llseek,
1898
1899         .open =         dev_open,
1900         .read =         ep0_read,
1901         .write =        dev_config,
1902         .fasync =       ep0_fasync,
1903         .poll =         ep0_poll,
1904         .unlocked_ioctl = dev_ioctl,
1905         .release =      dev_release,
1906 };
1907
1908 /*----------------------------------------------------------------------*/
1909
1910 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1911  *
1912  * Mounting the filesystem creates a controller file, used first for
1913  * device configuration then later for event monitoring.
1914  */
1915
1916
1917 /* FIXME PAM etc could set this security policy without mount options
1918  * if epfiles inherited ownership and permissons from ep0 ...
1919  */
1920
1921 static unsigned default_uid;
1922 static unsigned default_gid;
1923 static unsigned default_perm = S_IRUSR | S_IWUSR;
1924
1925 module_param (default_uid, uint, 0644);
1926 module_param (default_gid, uint, 0644);
1927 module_param (default_perm, uint, 0644);
1928
1929
1930 static struct inode *
1931 gadgetfs_make_inode (struct super_block *sb,
1932                 void *data, const struct file_operations *fops,
1933                 int mode)
1934 {
1935         struct inode *inode = new_inode (sb);
1936
1937         if (inode) {
1938                 inode->i_ino = get_next_ino();
1939                 inode->i_mode = mode;
1940                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
1941                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
1942                 inode->i_atime = inode->i_mtime = inode->i_ctime
1943                                 = CURRENT_TIME;
1944                 inode->i_private = data;
1945                 inode->i_fop = fops;
1946         }
1947         return inode;
1948 }
1949
1950 /* creates in fs root directory, so non-renamable and non-linkable.
1951  * so inode and dentry are paired, until device reconfig.
1952  */
1953 static struct dentry *
1954 gadgetfs_create_file (struct super_block *sb, char const *name,
1955                 void *data, const struct file_operations *fops)
1956 {
1957         struct dentry   *dentry;
1958         struct inode    *inode;
1959
1960         dentry = d_alloc_name(sb->s_root, name);
1961         if (!dentry)
1962                 return NULL;
1963
1964         inode = gadgetfs_make_inode (sb, data, fops,
1965                         S_IFREG | (default_perm & S_IRWXUGO));
1966         if (!inode) {
1967                 dput(dentry);
1968                 return NULL;
1969         }
1970         d_add (dentry, inode);
1971         return dentry;
1972 }
1973
1974 static const struct super_operations gadget_fs_operations = {
1975         .statfs =       simple_statfs,
1976         .drop_inode =   generic_delete_inode,
1977 };
1978
1979 static int
1980 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
1981 {
1982         struct inode    *inode;
1983         struct dev_data *dev;
1984
1985         if (the_device)
1986                 return -ESRCH;
1987
1988         /* fake probe to determine $CHIP */
1989         CHIP = NULL;
1990         usb_gadget_probe_driver(&probe_driver);
1991         if (!CHIP)
1992                 return -ENODEV;
1993
1994         /* superblock */
1995         sb->s_blocksize = PAGE_CACHE_SIZE;
1996         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1997         sb->s_magic = GADGETFS_MAGIC;
1998         sb->s_op = &gadget_fs_operations;
1999         sb->s_time_gran = 1;
2000
2001         /* root inode */
2002         inode = gadgetfs_make_inode (sb,
2003                         NULL, &simple_dir_operations,
2004                         S_IFDIR | S_IRUGO | S_IXUGO);
2005         if (!inode)
2006                 goto Enomem;
2007         inode->i_op = &simple_dir_inode_operations;
2008         if (!(sb->s_root = d_make_root (inode)))
2009                 goto Enomem;
2010
2011         /* the ep0 file is named after the controller we expect;
2012          * user mode code can use it for sanity checks, like we do.
2013          */
2014         dev = dev_new ();
2015         if (!dev)
2016                 goto Enomem;
2017
2018         dev->sb = sb;
2019         dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2020         if (!dev->dentry) {
2021                 put_dev(dev);
2022                 goto Enomem;
2023         }
2024
2025         /* other endpoint files are available after hardware setup,
2026          * from binding to a controller.
2027          */
2028         the_device = dev;
2029         return 0;
2030
2031 Enomem:
2032         return -ENOMEM;
2033 }
2034
2035 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2036 static struct dentry *
2037 gadgetfs_mount (struct file_system_type *t, int flags,
2038                 const char *path, void *opts)
2039 {
2040         return mount_single (t, flags, opts, gadgetfs_fill_super);
2041 }
2042
2043 static void
2044 gadgetfs_kill_sb (struct super_block *sb)
2045 {
2046         kill_litter_super (sb);
2047         if (the_device) {
2048                 put_dev (the_device);
2049                 the_device = NULL;
2050         }
2051 }
2052
2053 /*----------------------------------------------------------------------*/
2054
2055 static struct file_system_type gadgetfs_type = {
2056         .owner          = THIS_MODULE,
2057         .name           = shortname,
2058         .mount          = gadgetfs_mount,
2059         .kill_sb        = gadgetfs_kill_sb,
2060 };
2061 MODULE_ALIAS_FS("gadgetfs");
2062
2063 /*----------------------------------------------------------------------*/
2064
2065 static int __init init (void)
2066 {
2067         int status;
2068
2069         status = register_filesystem (&gadgetfs_type);
2070         if (status == 0)
2071                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2072                         shortname, driver_desc);
2073         return status;
2074 }
2075 module_init (init);
2076
2077 static void __exit cleanup (void)
2078 {
2079         pr_debug ("unregister %s\n", shortname);
2080         unregister_filesystem (&gadgetfs_type);
2081 }
2082 module_exit (cleanup);
2083