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