drivers/usb/gadget/legacy/inode.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * inode.c -- user mode filesystem api for usb gadget controllers
   4  *
   5  * Copyright (C) 2003-2004 David Brownell
   6  * Copyright (C) 2003 Agilent Technologies
   7  */
   8
   9
  10 /* #define VERBOSE_DEBUG */
  11
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/fs.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/uts.h>
  17 #include <linux/wait.h>
  18 #include <linux/compiler.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/sched.h>
  21 #include <linux/slab.h>
  22 #include <linux/poll.h>
  23 #include <linux/mmu_context.h>
  24 #include <linux/aio.h>
  25 #include <linux/uio.h>
  26 #include <linux/refcount.h>
  27 #include <linux/delay.h>
  28 #include <linux/device.h>
  29 #include <linux/moduleparam.h>
  30
  31 #include <linux/usb/gadgetfs.h>
  32 #include <linux/usb/gadget.h>
  33
  34
  35 /*
  36  * The gadgetfs API maps each endpoint to a file descriptor so that you
  37  * can use standard synchronous read/write calls for I/O.  There's some
  38  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  39  * drivers show how this works in practice.  You can also use AIO to
  40  * eliminate I/O gaps between requests, to help when streaming data.
  41  *
  42  * Key parts that must be USB-specific are protocols defining how the
  43  * read/write operations relate to the hardware state machines.  There
  44  * are two types of files.  One type is for the device, implementing ep0.
  45  * The other type is for each IN or OUT endpoint.  In both cases, the
  46  * user mode driver must configure the hardware before using it.
  47  *
  48  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  49  *   (by writing configuration and device descriptors).  Afterwards it
  50  *   may serve as a source of device events, used to handle all control
  51  *   requests other than basic enumeration.
  52  *
  53  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  54  *   called when each /dev/gadget/ep* file is configured (by writing
  55  *   endpoint descriptors).  Afterwards these files are used to write()
  56  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  57  *   direction" request is issued (like reading an IN endpoint).
  58  *
  59  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  60  * not possible on all hardware.  For example, precise fault handling with
  61  * respect to data left in endpoint fifos after aborted operations; or
  62  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  63  */
  64
  65 #define DRIVER_DESC     "USB Gadget filesystem"
  66 #define DRIVER_VERSION  "24 Aug 2004"
  67
  68 static const char driver_desc [] = DRIVER_DESC;
  69 static const char shortname [] = "gadgetfs";
  70
  71 MODULE_DESCRIPTION (DRIVER_DESC);
  72 MODULE_AUTHOR ("David Brownell");
  73 MODULE_LICENSE ("GPL");
  74
  75 static int ep_open(struct inode *, struct file *);
  76
  77
  78 /*----------------------------------------------------------------------*/
  79
  80 #define GADGETFS_MAGIC          0xaee71ee7
  81
  82 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  83 enum ep0_state {
  84         /* DISABLED is the initial state. */
  85         STATE_DEV_DISABLED = 0,
  86
  87         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  88          * ep0/device i/o modes and binding to the controller.  Driver
  89          * must always write descriptors to initialize the device, then
  90          * the device becomes UNCONNECTED until enumeration.
  91          */
  92         STATE_DEV_OPENED,
  93
  94         /* From then on, ep0 fd is in either of two basic modes:
  95          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
  96          * - SETUP: read/write will transfer control data and succeed;
  97          *   or if "wrong direction", performs protocol stall
  98          */
  99         STATE_DEV_UNCONNECTED,
 100         STATE_DEV_CONNECTED,
 101         STATE_DEV_SETUP,
 102
 103         /* UNBOUND means the driver closed ep0, so the device won't be
 104          * accessible again (DEV_DISABLED) until all fds are closed.
 105          */
 106         STATE_DEV_UNBOUND,
 107 };
 108
 109 /* enough for the whole queue: most events invalidate others */
 110 #define N_EVENT                 5
 111
 112 struct dev_data {
 113         spinlock_t                      lock;
 114         refcount_t                      count;
 115         int                             udc_usage;
 116         enum ep0_state                  state;          /* P: lock */
 117         struct usb_gadgetfs_event       event [N_EVENT];
 118         unsigned                        ev_next;
 119         struct fasync_struct            *fasync;
 120         u8                              current_config;
 121
 122         /* drivers reading ep0 MUST handle control requests (SETUP)
 123          * reported that way; else the host will time out.
 124          */
 125         unsigned                        usermode_setup : 1,
 126                                         setup_in : 1,
 127                                         setup_can_stall : 1,
 128                                         setup_out_ready : 1,
 129                                         setup_out_error : 1,
 130                                         setup_abort : 1,
 131                                         gadget_registered : 1;
 132         unsigned                        setup_wLength;
 133
 134         /* the rest is basically write-once */
 135         struct usb_config_descriptor    *config, *hs_config;
 136         struct usb_device_descriptor    *dev;
 137         struct usb_request              *req;
 138         struct usb_gadget               *gadget;
 139         struct list_head                epfiles;
 140         void                            *buf;
 141         wait_queue_head_t               wait;
 142         struct super_block              *sb;
 143         struct dentry                   *dentry;
 144
 145         /* except this scratch i/o buffer for ep0 */
 146         u8                              rbuf [256];
 147 };
 148
 149 static inline void get_dev (struct dev_data *data)
 150 {
 151         refcount_inc (&data->count);
 152 }
 153
 154 static void put_dev (struct dev_data *data)
 155 {
 156         if (likely (!refcount_dec_and_test (&data->count)))
 157                 return;
 158         /* needs no more cleanup */
 159         BUG_ON (waitqueue_active (&data->wait));
 160         kfree (data);
 161 }
 162
 163 static struct dev_data *dev_new (void)
 164 {
 165         struct dev_data         *dev;
 166
 167         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 168         if (!dev)
 169                 return NULL;
 170         dev->state = STATE_DEV_DISABLED;
 171         refcount_set (&dev->count, 1);
 172         spin_lock_init (&dev->lock);
 173         INIT_LIST_HEAD (&dev->epfiles);
 174         init_waitqueue_head (&dev->wait);
 175         return dev;
 176 }
 177
 178 /*----------------------------------------------------------------------*/
 179
 180 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 181 enum ep_state {
 182         STATE_EP_DISABLED = 0,
 183         STATE_EP_READY,
 184         STATE_EP_ENABLED,
 185         STATE_EP_UNBOUND,
 186 };
 187
 188 struct ep_data {
 189         struct mutex                    lock;
 190         enum ep_state                   state;
 191         refcount_t                      count;
 192         struct dev_data                 *dev;
 193         /* must hold dev->lock before accessing ep or req */
 194         struct usb_ep                   *ep;
 195         struct usb_request              *req;
 196         ssize_t                         status;
 197         char                            name [16];
 198         struct usb_endpoint_descriptor  desc, hs_desc;
 199         struct list_head                epfiles;
 200         wait_queue_head_t               wait;
 201         struct dentry                   *dentry;
 202 };
 203
 204 static inline void get_ep (struct ep_data *data)
 205 {
 206         refcount_inc (&data->count);
 207 }
 208
 209 static void put_ep (struct ep_data *data)
 210 {
 211         if (likely (!refcount_dec_and_test (&data->count)))
 212                 return;
 213         put_dev (data->dev);
 214         /* needs no more cleanup */
 215         BUG_ON (!list_empty (&data->epfiles));
 216         BUG_ON (waitqueue_active (&data->wait));
 217         kfree (data);
 218 }
 219
 220 /*----------------------------------------------------------------------*/
 221
 222 /* most "how to use the hardware" policy choices are in userspace:
 223  * mapping endpoint roles (which the driver needs) to the capabilities
 224  * which the usb controller has.  most of those capabilities are exposed
 225  * implicitly, starting with the driver name and then endpoint names.
 226  */
 227
 228 static const char *CHIP;
 229
 230 /*----------------------------------------------------------------------*/
 231
 232 /* NOTE:  don't use dev_printk calls before binding to the gadget
 233  * at the end of ep0 configuration, or after unbind.
 234  */
 235
 236 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 237 #define xprintk(d,level,fmt,args...) \
 238         printk(level "%s: " fmt , shortname , ## args)
 239
 240 #ifdef DEBUG
 241 #define DBG(dev,fmt,args...) \
 242         xprintk(dev , KERN_DEBUG , fmt , ## args)
 243 #else
 244 #define DBG(dev,fmt,args...) \
 245         do { } while (0)
 246 #endif /* DEBUG */
 247
 248 #ifdef VERBOSE_DEBUG
 249 #define VDEBUG  DBG
 250 #else
 251 #define VDEBUG(dev,fmt,args...) \
 252         do { } while (0)
 253 #endif /* DEBUG */
 254
 255 #define ERROR(dev,fmt,args...) \
 256         xprintk(dev , KERN_ERR , fmt , ## args)
 257 #define INFO(dev,fmt,args...) \
 258         xprintk(dev , KERN_INFO , fmt , ## args)
 259
 260
 261 /*----------------------------------------------------------------------*/
 262
 263 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 264  *
 265  * After opening, configure non-control endpoints.  Then use normal
 266  * stream read() and write() requests; and maybe ioctl() to get more
 267  * precise FIFO status when recovering from cancellation.
 268  */
 269
 270 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 271 {
 272         struct ep_data  *epdata = ep->driver_data;
 273
 274         if (!req->context)
 275                 return;
 276         if (req->status)
 277                 epdata->status = req->status;
 278         else
 279                 epdata->status = req->actual;
 280         complete ((struct completion *)req->context);
 281 }
 282
 283 /* tasklock endpoint, returning when it's connected.
 284  * still need dev->lock to use epdata->ep.
 285  */
 286 static int
 287 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 288 {
 289         int     val;
 290
 291         if (f_flags & O_NONBLOCK) {
 292                 if (!mutex_trylock(&epdata->lock))
 293                         goto nonblock;
 294                 if (epdata->state != STATE_EP_ENABLED &&
 295                     (!is_write || epdata->state != STATE_EP_READY)) {
 296                         mutex_unlock(&epdata->lock);
 297 nonblock:
 298                         val = -EAGAIN;
 299                 } else
 300                         val = 0;
 301                 return val;
 302         }
 303
 304         val = mutex_lock_interruptible(&epdata->lock);
 305         if (val < 0)
 306                 return val;
 307
 308         switch (epdata->state) {
 309         case STATE_EP_ENABLED:
 310                 return 0;
 311         case STATE_EP_READY:                    /* not configured yet */
 312                 if (is_write)
 313                         return 0;
 314                 // FALLTHRU
 315         case STATE_EP_UNBOUND:                  /* clean disconnect */
 316                 break;
 317         // case STATE_EP_DISABLED:              /* "can't happen" */
 318         default:                                /* error! */
 319                 pr_debug ("%s: ep %p not available, state %d\n",
 320                                 shortname, epdata, epdata->state);
 321         }
 322         mutex_unlock(&epdata->lock);
 323         return -ENODEV;
 324 }
 325
 326 static ssize_t
 327 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 328 {
 329         DECLARE_COMPLETION_ONSTACK (done);
 330         int value;
 331
 332         spin_lock_irq (&epdata->dev->lock);
 333         if (likely (epdata->ep != NULL)) {
 334                 struct usb_request      *req = epdata->req;
 335
 336                 req->context = &done;
 337                 req->complete = epio_complete;
 338                 req->buf = buf;
 339                 req->length = len;
 340                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 341         } else
 342                 value = -ENODEV;
 343         spin_unlock_irq (&epdata->dev->lock);
 344
 345         if (likely (value == 0)) {
 346                 value = wait_event_interruptible (done.wait, done.done);
 347                 if (value != 0) {
 348                         spin_lock_irq (&epdata->dev->lock);
 349                         if (likely (epdata->ep != NULL)) {
 350                                 DBG (epdata->dev, "%s i/o interrupted\n",
 351                                                 epdata->name);
 352                                 usb_ep_dequeue (epdata->ep, epdata->req);
 353                                 spin_unlock_irq (&epdata->dev->lock);
 354
 355                                 wait_event (done.wait, done.done);
 356                                 if (epdata->status == -ECONNRESET)
 357                                         epdata->status = -EINTR;
 358                         } else {
 359                                 spin_unlock_irq (&epdata->dev->lock);
 360
 361                                 DBG (epdata->dev, "endpoint gone\n");
 362                                 epdata->status = -ENODEV;
 363                         }
 364                 }
 365                 return epdata->status;
 366         }
 367         return value;
 368 }
 369
 370 static int
 371 ep_release (struct inode *inode, struct file *fd)
 372 {
 373         struct ep_data          *data = fd->private_data;
 374         int value;
 375
 376         value = mutex_lock_interruptible(&data->lock);
 377         if (value < 0)
 378                 return value;
 379
 380         /* clean up if this can be reopened */
 381         if (data->state != STATE_EP_UNBOUND) {
 382                 data->state = STATE_EP_DISABLED;
 383                 data->desc.bDescriptorType = 0;
 384                 data->hs_desc.bDescriptorType = 0;
 385                 usb_ep_disable(data->ep);
 386         }
 387         mutex_unlock(&data->lock);
 388         put_ep (data);
 389         return 0;
 390 }
 391
 392 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 393 {
 394         struct ep_data          *data = fd->private_data;
 395         int                     status;
 396
 397         if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
 398                 return status;
 399
 400         spin_lock_irq (&data->dev->lock);
 401         if (likely (data->ep != NULL)) {
 402                 switch (code) {
 403                 case GADGETFS_FIFO_STATUS:
 404                         status = usb_ep_fifo_status (data->ep);
 405                         break;
 406                 case GADGETFS_FIFO_FLUSH:
 407                         usb_ep_fifo_flush (data->ep);
 408                         break;
 409                 case GADGETFS_CLEAR_HALT:
 410                         status = usb_ep_clear_halt (data->ep);
 411                         break;
 412                 default:
 413                         status = -ENOTTY;
 414                 }
 415         } else
 416                 status = -ENODEV;
 417         spin_unlock_irq (&data->dev->lock);
 418         mutex_unlock(&data->lock);
 419         return status;
 420 }
 421
 422 /*----------------------------------------------------------------------*/
 423
 424 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 425
 426 struct kiocb_priv {
 427         struct usb_request      *req;
 428         struct ep_data          *epdata;
 429         struct kiocb            *iocb;
 430         struct mm_struct        *mm;
 431         struct work_struct      work;
 432         void                    *buf;
 433         struct iov_iter         to;
 434         const void              *to_free;
 435         unsigned                actual;
 436 };
 437
 438 static int ep_aio_cancel(struct kiocb *iocb)
 439 {
 440         struct kiocb_priv       *priv = iocb->private;
 441         struct ep_data          *epdata;
 442         int                     value;
 443
 444         local_irq_disable();
 445         epdata = priv->epdata;
 446         // spin_lock(&epdata->dev->lock);
 447         if (likely(epdata && epdata->ep && priv->req))
 448                 value = usb_ep_dequeue (epdata->ep, priv->req);
 449         else
 450                 value = -EINVAL;
 451         // spin_unlock(&epdata->dev->lock);
 452         local_irq_enable();
 453
 454         return value;
 455 }
 456
 457 static void ep_user_copy_worker(struct work_struct *work)
 458 {
 459         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 460         struct mm_struct *mm = priv->mm;
 461         struct kiocb *iocb = priv->iocb;
 462         size_t ret;
 463
 464         use_mm(mm);
 465         ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
 466         unuse_mm(mm);
 467         if (!ret)
 468                 ret = -EFAULT;
 469
 470         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 471         iocb->ki_complete(iocb, ret, ret);
 472
 473         kfree(priv->buf);
 474         kfree(priv->to_free);
 475         kfree(priv);
 476 }
 477
 478 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 479 {
 480         struct kiocb            *iocb = req->context;
 481         struct kiocb_priv       *priv = iocb->private;
 482         struct ep_data          *epdata = priv->epdata;
 483
 484         /* lock against disconnect (and ideally, cancel) */
 485         spin_lock(&epdata->dev->lock);
 486         priv->req = NULL;
 487         priv->epdata = NULL;
 488
 489         /* if this was a write or a read returning no data then we
 490          * don't need to copy anything to userspace, so we can
 491          * complete the aio request immediately.
 492          */
 493         if (priv->to_free == NULL || unlikely(req->actual == 0)) {
 494                 kfree(req->buf);
 495                 kfree(priv->to_free);
 496                 kfree(priv);
 497                 iocb->private = NULL;
 498                 /* aio_complete() reports bytes-transferred _and_ faults */
 499
 500                 iocb->ki_complete(iocb, req->actual ? req->actual : req->status,
 501                                 req->status);
 502         } else {
 503                 /* ep_copy_to_user() won't report both; we hide some faults */
 504                 if (unlikely(0 != req->status))
 505                         DBG(epdata->dev, "%s fault %d len %d\n",
 506                                 ep->name, req->status, req->actual);
 507
 508                 priv->buf = req->buf;
 509                 priv->actual = req->actual;
 510                 INIT_WORK(&priv->work, ep_user_copy_worker);
 511                 schedule_work(&priv->work);
 512         }
 513
 514         usb_ep_free_request(ep, req);
 515         spin_unlock(&epdata->dev->lock);
 516         put_ep(epdata);
 517 }
 518
 519 static ssize_t ep_aio(struct kiocb *iocb,
 520                       struct kiocb_priv *priv,
 521                       struct ep_data *epdata,
 522                       char *buf,
 523                       size_t len)
 524 {
 525         struct usb_request *req;
 526         ssize_t value;
 527
 528         iocb->private = priv;
 529         priv->iocb = iocb;
 530
 531         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 532         get_ep(epdata);
 533         priv->epdata = epdata;
 534         priv->actual = 0;
 535         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 536
 537         /* each kiocb is coupled to one usb_request, but we can't
 538          * allocate or submit those if the host disconnected.
 539          */
 540         spin_lock_irq(&epdata->dev->lock);
 541         value = -ENODEV;
 542         if (unlikely(epdata->ep == NULL))
 543                 goto fail;
 544
 545         req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 546         value = -ENOMEM;
 547         if (unlikely(!req))
 548                 goto fail;
 549
 550         priv->req = req;
 551         req->buf = buf;
 552         req->length = len;
 553         req->complete = ep_aio_complete;
 554         req->context = iocb;
 555         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 556         if (unlikely(0 != value)) {
 557                 usb_ep_free_request(epdata->ep, req);
 558                 goto fail;
 559         }
 560         spin_unlock_irq(&epdata->dev->lock);
 561         return -EIOCBQUEUED;
 562
 563 fail:
 564         spin_unlock_irq(&epdata->dev->lock);
 565         kfree(priv->to_free);
 566         kfree(priv);
 567         put_ep(epdata);
 568         return value;
 569 }
 570
 571 static ssize_t
 572 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 573 {
 574         struct file *file = iocb->ki_filp;
 575         struct ep_data *epdata = file->private_data;
 576         size_t len = iov_iter_count(to);
 577         ssize_t value;
 578         char *buf;
 579
 580         if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
 581                 return value;
 582
 583         /* halt any endpoint by doing a "wrong direction" i/o call */
 584         if (usb_endpoint_dir_in(&epdata->desc)) {
 585                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 586                     !is_sync_kiocb(iocb)) {
 587                         mutex_unlock(&epdata->lock);
 588                         return -EINVAL;
 589                 }
 590                 DBG (epdata->dev, "%s halt\n", epdata->name);
 591                 spin_lock_irq(&epdata->dev->lock);
 592                 if (likely(epdata->ep != NULL))
 593                         usb_ep_set_halt(epdata->ep);
 594                 spin_unlock_irq(&epdata->dev->lock);
 595                 mutex_unlock(&epdata->lock);
 596                 return -EBADMSG;
 597         }
 598
 599         buf = kmalloc(len, GFP_KERNEL);
 600         if (unlikely(!buf)) {
 601                 mutex_unlock(&epdata->lock);
 602                 return -ENOMEM;
 603         }
 604         if (is_sync_kiocb(iocb)) {
 605                 value = ep_io(epdata, buf, len);
 606                 if (value >= 0 && (copy_to_iter(buf, value, to) != value))
 607                         value = -EFAULT;
 608         } else {
 609                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 610                 value = -ENOMEM;
 611                 if (!priv)
 612                         goto fail;
 613                 priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
 614                 if (!priv->to_free) {
 615                         kfree(priv);
 616                         goto fail;
 617                 }
 618                 value = ep_aio(iocb, priv, epdata, buf, len);
 619                 if (value == -EIOCBQUEUED)
 620                         buf = NULL;
 621         }
 622 fail:
 623         kfree(buf);
 624         mutex_unlock(&epdata->lock);
 625         return value;
 626 }
 627
 628 static ssize_t ep_config(struct ep_data *, const char *, size_t);
 629
 630 static ssize_t
 631 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 632 {
 633         struct file *file = iocb->ki_filp;
 634         struct ep_data *epdata = file->private_data;
 635         size_t len = iov_iter_count(from);
 636         bool configured;
 637         ssize_t value;
 638         char *buf;
 639
 640         if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
 641                 return value;
 642
 643         configured = epdata->state == STATE_EP_ENABLED;
 644
 645         /* halt any endpoint by doing a "wrong direction" i/o call */
 646         if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
 647                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 648                     !is_sync_kiocb(iocb)) {
 649                         mutex_unlock(&epdata->lock);
 650                         return -EINVAL;
 651                 }
 652                 DBG (epdata->dev, "%s halt\n", epdata->name);
 653                 spin_lock_irq(&epdata->dev->lock);
 654                 if (likely(epdata->ep != NULL))
 655                         usb_ep_set_halt(epdata->ep);
 656                 spin_unlock_irq(&epdata->dev->lock);
 657                 mutex_unlock(&epdata->lock);
 658                 return -EBADMSG;
 659         }
 660
 661         buf = kmalloc(len, GFP_KERNEL);
 662         if (unlikely(!buf)) {
 663                 mutex_unlock(&epdata->lock);
 664                 return -ENOMEM;
 665         }
 666
 667         if (unlikely(!copy_from_iter_full(buf, len, from))) {
 668                 value = -EFAULT;
 669                 goto out;
 670         }
 671
 672         if (unlikely(!configured)) {
 673                 value = ep_config(epdata, buf, len);
 674         } else if (is_sync_kiocb(iocb)) {
 675                 value = ep_io(epdata, buf, len);
 676         } else {
 677                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 678                 value = -ENOMEM;
 679                 if (priv) {
 680                         value = ep_aio(iocb, priv, epdata, buf, len);
 681                         if (value == -EIOCBQUEUED)
 682                                 buf = NULL;
 683                 }
 684         }
 685 out:
 686         kfree(buf);
 687         mutex_unlock(&epdata->lock);
 688         return value;
 689 }
 690
 691 /*----------------------------------------------------------------------*/
 692
 693 /* used after endpoint configuration */
 694 static const struct file_operations ep_io_operations = {
 695         .owner =        THIS_MODULE,
 696
 697         .open =         ep_open,
 698         .release =      ep_release,
 699         .llseek =       no_llseek,
 700         .unlocked_ioctl = ep_ioctl,
 701         .read_iter =    ep_read_iter,
 702         .write_iter =   ep_write_iter,
 703 };
 704
 705 /* ENDPOINT INITIALIZATION
 706  *
 707  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 708  *     status = write (fd, descriptors, sizeof descriptors)
 709  *
 710  * That write establishes the endpoint configuration, configuring
 711  * the controller to process bulk, interrupt, or isochronous transfers
 712  * at the right maxpacket size, and so on.
 713  *
 714  * The descriptors are message type 1, identified by a host order u32
 715  * at the beginning of what's written.  Descriptor order is: full/low
 716  * speed descriptor, then optional high speed descriptor.
 717  */
 718 static ssize_t
 719 ep_config (struct ep_data *data, const char *buf, size_t len)
 720 {
 721         struct usb_ep           *ep;
 722         u32                     tag;
 723         int                     value, length = len;
 724
 725         if (data->state != STATE_EP_READY) {
 726                 value = -EL2HLT;
 727                 goto fail;
 728         }
 729
 730         value = len;
 731         if (len < USB_DT_ENDPOINT_SIZE + 4)
 732                 goto fail0;
 733
 734         /* we might need to change message format someday */
 735         memcpy(&tag, buf, 4);
 736         if (tag != 1) {
 737                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 738                 goto fail0;
 739         }
 740         buf += 4;
 741         len -= 4;
 742
 743         /* NOTE:  audio endpoint extensions not accepted here;
 744          * just don't include the extra bytes.
 745          */
 746
 747         /* full/low speed descriptor, then high speed */
 748         memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
 749         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 750                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 751                 goto fail0;
 752         if (len != USB_DT_ENDPOINT_SIZE) {
 753                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 754                         goto fail0;
 755                 memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 756                         USB_DT_ENDPOINT_SIZE);
 757                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 758                                 || data->hs_desc.bDescriptorType
 759                                         != USB_DT_ENDPOINT) {
 760                         DBG(data->dev, "config %s, bad hs length or type\n",
 761                                         data->name);
 762                         goto fail0;
 763                 }
 764         }
 765
 766         spin_lock_irq (&data->dev->lock);
 767         if (data->dev->state == STATE_DEV_UNBOUND) {
 768                 value = -ENOENT;
 769                 goto gone;
 770         } else {
 771                 ep = data->ep;
 772                 if (ep == NULL) {
 773                         value = -ENODEV;
 774                         goto gone;
 775                 }
 776         }
 777         switch (data->dev->gadget->speed) {
 778         case USB_SPEED_LOW:
 779         case USB_SPEED_FULL:
 780                 ep->desc = &data->desc;
 781                 break;
 782         case USB_SPEED_HIGH:
 783                 /* fails if caller didn't provide that descriptor... */
 784                 ep->desc = &data->hs_desc;
 785                 break;
 786         default:
 787                 DBG(data->dev, "unconnected, %s init abandoned\n",
 788                                 data->name);
 789                 value = -EINVAL;
 790                 goto gone;
 791         }
 792         value = usb_ep_enable(ep);
 793         if (value == 0) {
 794                 data->state = STATE_EP_ENABLED;
 795                 value = length;
 796         }
 797 gone:
 798         spin_unlock_irq (&data->dev->lock);
 799         if (value < 0) {
 800 fail:
 801                 data->desc.bDescriptorType = 0;
 802                 data->hs_desc.bDescriptorType = 0;
 803         }
 804         return value;
 805 fail0:
 806         value = -EINVAL;
 807         goto fail;
 808 }
 809
 810 static int
 811 ep_open (struct inode *inode, struct file *fd)
 812 {
 813         struct ep_data          *data = inode->i_private;
 814         int                     value = -EBUSY;
 815
 816         if (mutex_lock_interruptible(&data->lock) != 0)
 817                 return -EINTR;
 818         spin_lock_irq (&data->dev->lock);
 819         if (data->dev->state == STATE_DEV_UNBOUND)
 820                 value = -ENOENT;
 821         else if (data->state == STATE_EP_DISABLED) {
 822                 value = 0;
 823                 data->state = STATE_EP_READY;
 824                 get_ep (data);
 825                 fd->private_data = data;
 826                 VDEBUG (data->dev, "%s ready\n", data->name);
 827         } else
 828                 DBG (data->dev, "%s state %d\n",
 829                         data->name, data->state);
 830         spin_unlock_irq (&data->dev->lock);
 831         mutex_unlock(&data->lock);
 832         return value;
 833 }
 834
 835 /*----------------------------------------------------------------------*/
 836
 837 /* EP0 IMPLEMENTATION can be partly in userspace.
 838  *
 839  * Drivers that use this facility receive various events, including
 840  * control requests the kernel doesn't handle.  Drivers that don't
 841  * use this facility may be too simple-minded for real applications.
 842  */
 843
 844 static inline void ep0_readable (struct dev_data *dev)
 845 {
 846         wake_up (&dev->wait);
 847         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 848 }
 849
 850 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 851 {
 852         struct dev_data         *dev = ep->driver_data;
 853
 854         if (req->buf != dev->rbuf) {
 855                 kfree(req->buf);
 856                 req->buf = dev->rbuf;
 857         }
 858         req->complete = epio_complete;
 859         dev->setup_out_ready = 0;
 860 }
 861
 862 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 863 {
 864         struct dev_data         *dev = ep->driver_data;
 865         unsigned long           flags;
 866         int                     free = 1;
 867
 868         /* for control OUT, data must still get to userspace */
 869         spin_lock_irqsave(&dev->lock, flags);
 870         if (!dev->setup_in) {
 871                 dev->setup_out_error = (req->status != 0);
 872                 if (!dev->setup_out_error)
 873                         free = 0;
 874                 dev->setup_out_ready = 1;
 875                 ep0_readable (dev);
 876         }
 877
 878         /* clean up as appropriate */
 879         if (free && req->buf != &dev->rbuf)
 880                 clean_req (ep, req);
 881         req->complete = epio_complete;
 882         spin_unlock_irqrestore(&dev->lock, flags);
 883 }
 884
 885 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 886 {
 887         struct dev_data *dev = ep->driver_data;
 888
 889         if (dev->setup_out_ready) {
 890                 DBG (dev, "ep0 request busy!\n");
 891                 return -EBUSY;
 892         }
 893         if (len > sizeof (dev->rbuf))
 894                 req->buf = kmalloc(len, GFP_ATOMIC);
 895         if (req->buf == NULL) {
 896                 req->buf = dev->rbuf;
 897                 return -ENOMEM;
 898         }
 899         req->complete = ep0_complete;
 900         req->length = len;
 901         req->zero = 0;
 902         return 0;
 903 }
 904
 905 static ssize_t
 906 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 907 {
 908         struct dev_data                 *dev = fd->private_data;
 909         ssize_t                         retval;
 910         enum ep0_state                  state;
 911
 912         spin_lock_irq (&dev->lock);
 913         if (dev->state <= STATE_DEV_OPENED) {
 914                 retval = -EINVAL;
 915                 goto done;
 916         }
 917
 918         /* report fd mode change before acting on it */
 919         if (dev->setup_abort) {
 920                 dev->setup_abort = 0;
 921                 retval = -EIDRM;
 922                 goto done;
 923         }
 924
 925         /* control DATA stage */
 926         if ((state = dev->state) == STATE_DEV_SETUP) {
 927
 928                 if (dev->setup_in) {            /* stall IN */
 929                         VDEBUG(dev, "ep0in stall\n");
 930                         (void) usb_ep_set_halt (dev->gadget->ep0);
 931                         retval = -EL2HLT;
 932                         dev->state = STATE_DEV_CONNECTED;
 933
 934                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
 935                         struct usb_ep           *ep = dev->gadget->ep0;
 936                         struct usb_request      *req = dev->req;
 937
 938                         if ((retval = setup_req (ep, req, 0)) == 0) {
 939                                 ++dev->udc_usage;
 940                                 spin_unlock_irq (&dev->lock);
 941                                 retval = usb_ep_queue (ep, req, GFP_KERNEL);
 942                                 spin_lock_irq (&dev->lock);
 943                                 --dev->udc_usage;
 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                                 ++dev->udc_usage;
 986                                 spin_unlock_irq(&dev->lock);
 987                                 if (copy_to_user (buf, dev->req->buf, len))
 988                                         retval = -EFAULT;
 989                                 else
 990                                         retval = len;
 991                                 spin_lock_irq(&dev->lock);
 992                                 --dev->udc_usage;
 993                                 clean_req (dev->gadget->ep0, dev->req);
 994                                 /* NOTE userspace can't yet choose to stall */
 995                         }
 996                 }
 997                 goto done;
 998         }
 999
1000         /* else normal: return event data */
1001         if (len < sizeof dev->event [0]) {
1002                 retval = -EINVAL;
1003                 goto done;
1004         }
1005         len -= len % sizeof (struct usb_gadgetfs_event);
1006         dev->usermode_setup = 1;
1007
1008 scan:
1009         /* return queued events right away */
1010         if (dev->ev_next != 0) {
1011                 unsigned                i, n;
1012
1013                 n = len / sizeof (struct usb_gadgetfs_event);
1014                 if (dev->ev_next < n)
1015                         n = dev->ev_next;
1016
1017                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1018                 for (i = 0; i < n; i++) {
1019                         if (dev->event [i].type == GADGETFS_SETUP) {
1020                                 dev->state = STATE_DEV_SETUP;
1021                                 n = i + 1;
1022                                 break;
1023                         }
1024                 }
1025                 spin_unlock_irq (&dev->lock);
1026                 len = n * sizeof (struct usb_gadgetfs_event);
1027                 if (copy_to_user (buf, &dev->event, len))
1028                         retval = -EFAULT;
1029                 else
1030                         retval = len;
1031                 if (len > 0) {
1032                         /* NOTE this doesn't guard against broken drivers;
1033                          * concurrent ep0 readers may lose events.
1034                          */
1035                         spin_lock_irq (&dev->lock);
1036                         if (dev->ev_next > n) {
1037                                 memmove(&dev->event[0], &dev->event[n],
1038                                         sizeof (struct usb_gadgetfs_event)
1039                                                 * (dev->ev_next - n));
1040                         }
1041                         dev->ev_next -= n;
1042                         spin_unlock_irq (&dev->lock);
1043                 }
1044                 return retval;
1045         }
1046         if (fd->f_flags & O_NONBLOCK) {
1047                 retval = -EAGAIN;
1048                 goto done;
1049         }
1050
1051         switch (state) {
1052         default:
1053                 DBG (dev, "fail %s, state %d\n", __func__, state);
1054                 retval = -ESRCH;
1055                 break;
1056         case STATE_DEV_UNCONNECTED:
1057         case STATE_DEV_CONNECTED:
1058                 spin_unlock_irq (&dev->lock);
1059                 DBG (dev, "%s wait\n", __func__);
1060
1061                 /* wait for events */
1062                 retval = wait_event_interruptible (dev->wait,
1063                                 dev->ev_next != 0);
1064                 if (retval < 0)
1065                         return retval;
1066                 spin_lock_irq (&dev->lock);
1067                 goto scan;
1068         }
1069
1070 done:
1071         spin_unlock_irq (&dev->lock);
1072         return retval;
1073 }
1074
1075 static struct usb_gadgetfs_event *
1076 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1077 {
1078         struct usb_gadgetfs_event       *event;
1079         unsigned                        i;
1080
1081         switch (type) {
1082         /* these events purge the queue */
1083         case GADGETFS_DISCONNECT:
1084                 if (dev->state == STATE_DEV_SETUP)
1085                         dev->setup_abort = 1;
1086                 // FALL THROUGH
1087         case GADGETFS_CONNECT:
1088                 dev->ev_next = 0;
1089                 break;
1090         case GADGETFS_SETUP:            /* previous request timed out */
1091         case GADGETFS_SUSPEND:          /* same effect */
1092                 /* these events can't be repeated */
1093                 for (i = 0; i != dev->ev_next; i++) {
1094                         if (dev->event [i].type != type)
1095                                 continue;
1096                         DBG(dev, "discard old event[%d] %d\n", i, type);
1097                         dev->ev_next--;
1098                         if (i == dev->ev_next)
1099                                 break;
1100                         /* indices start at zero, for simplicity */
1101                         memmove (&dev->event [i], &dev->event [i + 1],
1102                                 sizeof (struct usb_gadgetfs_event)
1103                                         * (dev->ev_next - i));
1104                 }
1105                 break;
1106         default:
1107                 BUG ();
1108         }
1109         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1110         event = &dev->event [dev->ev_next++];
1111         BUG_ON (dev->ev_next > N_EVENT);
1112         memset (event, 0, sizeof *event);
1113         event->type = type;
1114         return event;
1115 }
1116
1117 static ssize_t
1118 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1119 {
1120         struct dev_data         *dev = fd->private_data;
1121         ssize_t                 retval = -ESRCH;
1122
1123         /* report fd mode change before acting on it */
1124         if (dev->setup_abort) {
1125                 dev->setup_abort = 0;
1126                 retval = -EIDRM;
1127
1128         /* data and/or status stage for control request */
1129         } else if (dev->state == STATE_DEV_SETUP) {
1130
1131                 len = min_t(size_t, len, dev->setup_wLength);
1132                 if (dev->setup_in) {
1133                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1134                         if (retval == 0) {
1135                                 dev->state = STATE_DEV_CONNECTED;
1136                                 ++dev->udc_usage;
1137                                 spin_unlock_irq (&dev->lock);
1138                                 if (copy_from_user (dev->req->buf, buf, len))
1139                                         retval = -EFAULT;
1140                                 else {
1141                                         if (len < dev->setup_wLength)
1142                                                 dev->req->zero = 1;
1143                                         retval = usb_ep_queue (
1144                                                 dev->gadget->ep0, dev->req,
1145                                                 GFP_KERNEL);
1146                                 }
1147                                 spin_lock_irq(&dev->lock);
1148                                 --dev->udc_usage;
1149                                 if (retval < 0) {
1150                                         clean_req (dev->gadget->ep0, dev->req);
1151                                 } else
1152                                         retval = len;
1153
1154                                 return retval;
1155                         }
1156
1157                 /* can stall some OUT transfers */
1158                 } else if (dev->setup_can_stall) {
1159                         VDEBUG(dev, "ep0out stall\n");
1160                         (void) usb_ep_set_halt (dev->gadget->ep0);
1161                         retval = -EL2HLT;
1162                         dev->state = STATE_DEV_CONNECTED;
1163                 } else {
1164                         DBG(dev, "bogus ep0out stall!\n");
1165                 }
1166         } else
1167                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1168
1169         return retval;
1170 }
1171
1172 static int
1173 ep0_fasync (int f, struct file *fd, int on)
1174 {
1175         struct dev_data         *dev = fd->private_data;
1176         // caller must F_SETOWN before signal delivery happens
1177         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1178         return fasync_helper (f, fd, on, &dev->fasync);
1179 }
1180
1181 static struct usb_gadget_driver gadgetfs_driver;
1182
1183 static int
1184 dev_release (struct inode *inode, struct file *fd)
1185 {
1186         struct dev_data         *dev = fd->private_data;
1187
1188         /* closing ep0 === shutdown all */
1189
1190         if (dev->gadget_registered) {
1191                 usb_gadget_unregister_driver (&gadgetfs_driver);
1192                 dev->gadget_registered = false;
1193         }
1194
1195         /* at this point "good" hardware has disconnected the
1196          * device from USB; the host won't see it any more.
1197          * alternatively, all host requests will time out.
1198          */
1199
1200         kfree (dev->buf);
1201         dev->buf = NULL;
1202
1203         /* other endpoints were all decoupled from this device */
1204         spin_lock_irq(&dev->lock);
1205         dev->state = STATE_DEV_DISABLED;
1206         spin_unlock_irq(&dev->lock);
1207
1208         put_dev (dev);
1209         return 0;
1210 }
1211
1212 static __poll_t
1213 ep0_poll (struct file *fd, poll_table *wait)
1214 {
1215        struct dev_data         *dev = fd->private_data;
1216        __poll_t                mask = 0;
1217
1218         if (dev->state <= STATE_DEV_OPENED)
1219                 return DEFAULT_POLLMASK;
1220
1221        poll_wait(fd, &dev->wait, wait);
1222
1223        spin_lock_irq (&dev->lock);
1224
1225        /* report fd mode change before acting on it */
1226        if (dev->setup_abort) {
1227                dev->setup_abort = 0;
1228                mask = POLLHUP;
1229                goto out;
1230        }
1231
1232        if (dev->state == STATE_DEV_SETUP) {
1233                if (dev->setup_in || dev->setup_can_stall)
1234                        mask = POLLOUT;
1235        } else {
1236                if (dev->ev_next != 0)
1237                        mask = POLLIN;
1238        }
1239 out:
1240        spin_unlock_irq(&dev->lock);
1241        return mask;
1242 }
1243
1244 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1245 {
1246         struct dev_data         *dev = fd->private_data;
1247         struct usb_gadget       *gadget = dev->gadget;
1248         long ret = -ENOTTY;
1249
1250         spin_lock_irq(&dev->lock);
1251         if (dev->state == STATE_DEV_OPENED ||
1252                         dev->state == STATE_DEV_UNBOUND) {
1253                 /* Not bound to a UDC */
1254         } else if (gadget->ops->ioctl) {
1255                 ++dev->udc_usage;
1256                 spin_unlock_irq(&dev->lock);
1257
1258                 ret = gadget->ops->ioctl (gadget, code, value);
1259
1260                 spin_lock_irq(&dev->lock);
1261                 --dev->udc_usage;
1262         }
1263         spin_unlock_irq(&dev->lock);
1264
1265         return ret;
1266 }
1267
1268 /*----------------------------------------------------------------------*/
1269
1270 /* The in-kernel gadget driver handles most ep0 issues, in particular
1271  * enumerating the single configuration (as provided from user space).
1272  *
1273  * Unrecognized ep0 requests may be handled in user space.
1274  */
1275
1276 static void make_qualifier (struct dev_data *dev)
1277 {
1278         struct usb_qualifier_descriptor         qual;
1279         struct usb_device_descriptor            *desc;
1280
1281         qual.bLength = sizeof qual;
1282         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1283         qual.bcdUSB = cpu_to_le16 (0x0200);
1284
1285         desc = dev->dev;
1286         qual.bDeviceClass = desc->bDeviceClass;
1287         qual.bDeviceSubClass = desc->bDeviceSubClass;
1288         qual.bDeviceProtocol = desc->bDeviceProtocol;
1289
1290         /* assumes ep0 uses the same value for both speeds ... */
1291         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1292
1293         qual.bNumConfigurations = 1;
1294         qual.bRESERVED = 0;
1295
1296         memcpy (dev->rbuf, &qual, sizeof qual);
1297 }
1298
1299 static int
1300 config_buf (struct dev_data *dev, u8 type, unsigned index)
1301 {
1302         int             len;
1303         int             hs = 0;
1304
1305         /* only one configuration */
1306         if (index > 0)
1307                 return -EINVAL;
1308
1309         if (gadget_is_dualspeed(dev->gadget)) {
1310                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1311                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1312                         hs = !hs;
1313         }
1314         if (hs) {
1315                 dev->req->buf = dev->hs_config;
1316                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1317         } else {
1318                 dev->req->buf = dev->config;
1319                 len = le16_to_cpu(dev->config->wTotalLength);
1320         }
1321         ((u8 *)dev->req->buf) [1] = type;
1322         return len;
1323 }
1324
1325 static int
1326 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1327 {
1328         struct dev_data                 *dev = get_gadget_data (gadget);
1329         struct usb_request              *req = dev->req;
1330         int                             value = -EOPNOTSUPP;
1331         struct usb_gadgetfs_event       *event;
1332         u16                             w_value = le16_to_cpu(ctrl->wValue);
1333         u16                             w_length = le16_to_cpu(ctrl->wLength);
1334
1335         spin_lock (&dev->lock);
1336         dev->setup_abort = 0;
1337         if (dev->state == STATE_DEV_UNCONNECTED) {
1338                 if (gadget_is_dualspeed(gadget)
1339                                 && gadget->speed == USB_SPEED_HIGH
1340                                 && dev->hs_config == NULL) {
1341                         spin_unlock(&dev->lock);
1342                         ERROR (dev, "no high speed config??\n");
1343                         return -EINVAL;
1344                 }
1345
1346                 dev->state = STATE_DEV_CONNECTED;
1347
1348                 INFO (dev, "connected\n");
1349                 event = next_event (dev, GADGETFS_CONNECT);
1350                 event->u.speed = gadget->speed;
1351                 ep0_readable (dev);
1352
1353         /* host may have given up waiting for response.  we can miss control
1354          * requests handled lower down (device/endpoint status and features);
1355          * then ep0_{read,write} will report the wrong status. controller
1356          * driver will have aborted pending i/o.
1357          */
1358         } else if (dev->state == STATE_DEV_SETUP)
1359                 dev->setup_abort = 1;
1360
1361         req->buf = dev->rbuf;
1362         req->context = NULL;
1363         value = -EOPNOTSUPP;
1364         switch (ctrl->bRequest) {
1365
1366         case USB_REQ_GET_DESCRIPTOR:
1367                 if (ctrl->bRequestType != USB_DIR_IN)
1368                         goto unrecognized;
1369                 switch (w_value >> 8) {
1370
1371                 case USB_DT_DEVICE:
1372                         value = min (w_length, (u16) sizeof *dev->dev);
1373                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1374                         req->buf = dev->dev;
1375                         break;
1376                 case USB_DT_DEVICE_QUALIFIER:
1377                         if (!dev->hs_config)
1378                                 break;
1379                         value = min (w_length, (u16)
1380                                 sizeof (struct usb_qualifier_descriptor));
1381                         make_qualifier (dev);
1382                         break;
1383                 case USB_DT_OTHER_SPEED_CONFIG:
1384                         // FALLTHROUGH
1385                 case USB_DT_CONFIG:
1386                         value = config_buf (dev,
1387                                         w_value >> 8,
1388                                         w_value & 0xff);
1389                         if (value >= 0)
1390                                 value = min (w_length, (u16) value);
1391                         break;
1392                 case USB_DT_STRING:
1393                         goto unrecognized;
1394
1395                 default:                // all others are errors
1396                         break;
1397                 }
1398                 break;
1399
1400         /* currently one config, two speeds */
1401         case USB_REQ_SET_CONFIGURATION:
1402                 if (ctrl->bRequestType != 0)
1403                         goto unrecognized;
1404                 if (0 == (u8) w_value) {
1405                         value = 0;
1406                         dev->current_config = 0;
1407                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1408                         // user mode expected to disable endpoints
1409                 } else {
1410                         u8      config, power;
1411
1412                         if (gadget_is_dualspeed(gadget)
1413                                         && gadget->speed == USB_SPEED_HIGH) {
1414                                 config = dev->hs_config->bConfigurationValue;
1415                                 power = dev->hs_config->bMaxPower;
1416                         } else {
1417                                 config = dev->config->bConfigurationValue;
1418                                 power = dev->config->bMaxPower;
1419                         }
1420
1421                         if (config == (u8) w_value) {
1422                                 value = 0;
1423                                 dev->current_config = config;
1424                                 usb_gadget_vbus_draw(gadget, 2 * power);
1425                         }
1426                 }
1427
1428                 /* report SET_CONFIGURATION like any other control request,
1429                  * except that usermode may not stall this.  the next
1430                  * request mustn't be allowed start until this finishes:
1431                  * endpoints and threads set up, etc.
1432                  *
1433                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1434                  * has bad/racey automagic that prevents synchronizing here.
1435                  * even kernel mode drivers often miss them.
1436                  */
1437                 if (value == 0) {
1438                         INFO (dev, "configuration #%d\n", dev->current_config);
1439                         usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1440                         if (dev->usermode_setup) {
1441                                 dev->setup_can_stall = 0;
1442                                 goto delegate;
1443                         }
1444                 }
1445                 break;
1446
1447 #ifndef CONFIG_USB_PXA25X
1448         /* PXA automagically handles this request too */
1449         case USB_REQ_GET_CONFIGURATION:
1450                 if (ctrl->bRequestType != 0x80)
1451                         goto unrecognized;
1452                 *(u8 *)req->buf = dev->current_config;
1453                 value = min (w_length, (u16) 1);
1454                 break;
1455 #endif
1456
1457         default:
1458 unrecognized:
1459                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1460                         dev->usermode_setup ? "delegate" : "fail",
1461                         ctrl->bRequestType, ctrl->bRequest,
1462                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1463
1464                 /* if there's an ep0 reader, don't stall */
1465                 if (dev->usermode_setup) {
1466                         dev->setup_can_stall = 1;
1467 delegate:
1468                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1469                                                 ? 1 : 0;
1470                         dev->setup_wLength = w_length;
1471                         dev->setup_out_ready = 0;
1472                         dev->setup_out_error = 0;
1473
1474                         /* read DATA stage for OUT right away */
1475                         if (unlikely (!dev->setup_in && w_length)) {
1476                                 value = setup_req (gadget->ep0, dev->req,
1477                                                         w_length);
1478                                 if (value < 0)
1479                                         break;
1480
1481                                 ++dev->udc_usage;
1482                                 spin_unlock (&dev->lock);
1483                                 value = usb_ep_queue (gadget->ep0, dev->req,
1484                                                         GFP_KERNEL);
1485                                 spin_lock (&dev->lock);
1486                                 --dev->udc_usage;
1487                                 if (value < 0) {
1488                                         clean_req (gadget->ep0, dev->req);
1489                                         break;
1490                                 }
1491
1492                                 /* we can't currently stall these */
1493                                 dev->setup_can_stall = 0;
1494                         }
1495
1496                         /* state changes when reader collects event */
1497                         event = next_event (dev, GADGETFS_SETUP);
1498                         event->u.setup = *ctrl;
1499                         ep0_readable (dev);
1500                         spin_unlock (&dev->lock);
1501                         return 0;
1502                 }
1503         }
1504
1505         /* proceed with data transfer and status phases? */
1506         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1507                 req->length = value;
1508                 req->zero = value < w_length;
1509
1510                 ++dev->udc_usage;
1511                 spin_unlock (&dev->lock);
1512                 value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1513                 spin_lock(&dev->lock);
1514                 --dev->udc_usage;
1515                 spin_unlock(&dev->lock);
1516                 if (value < 0) {
1517                         DBG (dev, "ep_queue --> %d\n", value);
1518                         req->status = 0;
1519                 }
1520                 return value;
1521         }
1522
1523         /* device stalls when value < 0 */
1524         spin_unlock (&dev->lock);
1525         return value;
1526 }
1527
1528 static void destroy_ep_files (struct dev_data *dev)
1529 {
1530         DBG (dev, "%s %d\n", __func__, dev->state);
1531
1532         /* dev->state must prevent interference */
1533         spin_lock_irq (&dev->lock);
1534         while (!list_empty(&dev->epfiles)) {
1535                 struct ep_data  *ep;
1536                 struct inode    *parent;
1537                 struct dentry   *dentry;
1538
1539                 /* break link to FS */
1540                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1541                 list_del_init (&ep->epfiles);
1542                 spin_unlock_irq (&dev->lock);
1543
1544                 dentry = ep->dentry;
1545                 ep->dentry = NULL;
1546                 parent = d_inode(dentry->d_parent);
1547
1548                 /* break link to controller */
1549                 mutex_lock(&ep->lock);
1550                 if (ep->state == STATE_EP_ENABLED)
1551                         (void) usb_ep_disable (ep->ep);
1552                 ep->state = STATE_EP_UNBOUND;
1553                 usb_ep_free_request (ep->ep, ep->req);
1554                 ep->ep = NULL;
1555                 mutex_unlock(&ep->lock);
1556
1557                 wake_up (&ep->wait);
1558                 put_ep (ep);
1559
1560                 /* break link to dcache */
1561                 inode_lock(parent);
1562                 d_delete (dentry);
1563                 dput (dentry);
1564                 inode_unlock(parent);
1565
1566                 spin_lock_irq (&dev->lock);
1567         }
1568         spin_unlock_irq (&dev->lock);
1569 }
1570
1571
1572 static struct dentry *
1573 gadgetfs_create_file (struct super_block *sb, char const *name,
1574                 void *data, const struct file_operations *fops);
1575
1576 static int activate_ep_files (struct dev_data *dev)
1577 {
1578         struct usb_ep   *ep;
1579         struct ep_data  *data;
1580
1581         gadget_for_each_ep (ep, dev->gadget) {
1582
1583                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1584                 if (!data)
1585                         goto enomem0;
1586                 data->state = STATE_EP_DISABLED;
1587                 mutex_init(&data->lock);
1588                 init_waitqueue_head (&data->wait);
1589
1590                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1591                 refcount_set (&data->count, 1);
1592                 data->dev = dev;
1593                 get_dev (dev);
1594
1595                 data->ep = ep;
1596                 ep->driver_data = data;
1597
1598                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1599                 if (!data->req)
1600                         goto enomem1;
1601
1602                 data->dentry = gadgetfs_create_file (dev->sb, data->name,
1603                                 data, &ep_io_operations);
1604                 if (!data->dentry)
1605                         goto enomem2;
1606                 list_add_tail (&data->epfiles, &dev->epfiles);
1607         }
1608         return 0;
1609
1610 enomem2:
1611         usb_ep_free_request (ep, data->req);
1612 enomem1:
1613         put_dev (dev);
1614         kfree (data);
1615 enomem0:
1616         DBG (dev, "%s enomem\n", __func__);
1617         destroy_ep_files (dev);
1618         return -ENOMEM;
1619 }
1620
1621 static void
1622 gadgetfs_unbind (struct usb_gadget *gadget)
1623 {
1624         struct dev_data         *dev = get_gadget_data (gadget);
1625
1626         DBG (dev, "%s\n", __func__);
1627
1628         spin_lock_irq (&dev->lock);
1629         dev->state = STATE_DEV_UNBOUND;
1630         while (dev->udc_usage > 0) {
1631                 spin_unlock_irq(&dev->lock);
1632                 usleep_range(1000, 2000);
1633                 spin_lock_irq(&dev->lock);
1634         }
1635         spin_unlock_irq (&dev->lock);
1636
1637         destroy_ep_files (dev);
1638         gadget->ep0->driver_data = NULL;
1639         set_gadget_data (gadget, NULL);
1640
1641         /* we've already been disconnected ... no i/o is active */
1642         if (dev->req)
1643                 usb_ep_free_request (gadget->ep0, dev->req);
1644         DBG (dev, "%s done\n", __func__);
1645         put_dev (dev);
1646 }
1647
1648 static struct dev_data          *the_device;
1649
1650 static int gadgetfs_bind(struct usb_gadget *gadget,
1651                 struct usb_gadget_driver *driver)
1652 {
1653         struct dev_data         *dev = the_device;
1654
1655         if (!dev)
1656                 return -ESRCH;
1657         if (0 != strcmp (CHIP, gadget->name)) {
1658                 pr_err("%s expected %s controller not %s\n",
1659                         shortname, CHIP, gadget->name);
1660                 return -ENODEV;
1661         }
1662
1663         set_gadget_data (gadget, dev);
1664         dev->gadget = gadget;
1665         gadget->ep0->driver_data = dev;
1666
1667         /* preallocate control response and buffer */
1668         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1669         if (!dev->req)
1670                 goto enomem;
1671         dev->req->context = NULL;
1672         dev->req->complete = epio_complete;
1673
1674         if (activate_ep_files (dev) < 0)
1675                 goto enomem;
1676
1677         INFO (dev, "bound to %s driver\n", gadget->name);
1678         spin_lock_irq(&dev->lock);
1679         dev->state = STATE_DEV_UNCONNECTED;
1680         spin_unlock_irq(&dev->lock);
1681         get_dev (dev);
1682         return 0;
1683
1684 enomem:
1685         gadgetfs_unbind (gadget);
1686         return -ENOMEM;
1687 }
1688
1689 static void
1690 gadgetfs_disconnect (struct usb_gadget *gadget)
1691 {
1692         struct dev_data         *dev = get_gadget_data (gadget);
1693         unsigned long           flags;
1694
1695         spin_lock_irqsave (&dev->lock, flags);
1696         if (dev->state == STATE_DEV_UNCONNECTED)
1697                 goto exit;
1698         dev->state = STATE_DEV_UNCONNECTED;
1699
1700         INFO (dev, "disconnected\n");
1701         next_event (dev, GADGETFS_DISCONNECT);
1702         ep0_readable (dev);
1703 exit:
1704         spin_unlock_irqrestore (&dev->lock, flags);
1705 }
1706
1707 static void
1708 gadgetfs_suspend (struct usb_gadget *gadget)
1709 {
1710         struct dev_data         *dev = get_gadget_data (gadget);
1711         unsigned long           flags;
1712
1713         INFO (dev, "suspended from state %d\n", dev->state);
1714         spin_lock_irqsave(&dev->lock, flags);
1715         switch (dev->state) {
1716         case STATE_DEV_SETUP:           // VERY odd... host died??
1717         case STATE_DEV_CONNECTED:
1718         case STATE_DEV_UNCONNECTED:
1719                 next_event (dev, GADGETFS_SUSPEND);
1720                 ep0_readable (dev);
1721                 /* FALLTHROUGH */
1722         default:
1723                 break;
1724         }
1725         spin_unlock_irqrestore(&dev->lock, flags);
1726 }
1727
1728 static struct usb_gadget_driver gadgetfs_driver = {
1729         .function       = (char *) driver_desc,
1730         .bind           = gadgetfs_bind,
1731         .unbind         = gadgetfs_unbind,
1732         .setup          = gadgetfs_setup,
1733         .reset          = gadgetfs_disconnect,
1734         .disconnect     = gadgetfs_disconnect,
1735         .suspend        = gadgetfs_suspend,
1736
1737         .driver = {
1738                 .name           = (char *) shortname,
1739         },
1740 };
1741
1742 /*----------------------------------------------------------------------*/
1743 /* DEVICE INITIALIZATION
1744  *
1745  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1746  *     status = write (fd, descriptors, sizeof descriptors)
1747  *
1748  * That write establishes the device configuration, so the kernel can
1749  * bind to the controller ... guaranteeing it can handle enumeration
1750  * at all necessary speeds.  Descriptor order is:
1751  *
1752  * . message tag (u32, host order) ... for now, must be zero; it
1753  *      would change to support features like multi-config devices
1754  * . full/low speed config ... all wTotalLength bytes (with interface,
1755  *      class, altsetting, endpoint, and other descriptors)
1756  * . high speed config ... all descriptors, for high speed operation;
1757  *      this one's optional except for high-speed hardware
1758  * . device descriptor
1759  *
1760  * Endpoints are not yet enabled. Drivers must wait until device
1761  * configuration and interface altsetting changes create
1762  * the need to configure (or unconfigure) them.
1763  *
1764  * After initialization, the device stays active for as long as that
1765  * $CHIP file is open.  Events must then be read from that descriptor,
1766  * such as configuration notifications.
1767  */
1768
1769 static int is_valid_config(struct usb_config_descriptor *config,
1770                 unsigned int total)
1771 {
1772         return config->bDescriptorType == USB_DT_CONFIG
1773                 && config->bLength == USB_DT_CONFIG_SIZE
1774                 && total >= USB_DT_CONFIG_SIZE
1775                 && config->bConfigurationValue != 0
1776                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1777                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1778         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1779         /* FIXME check lengths: walk to end */
1780 }
1781
1782 static ssize_t
1783 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1784 {
1785         struct dev_data         *dev = fd->private_data;
1786         ssize_t                 value = len, length = len;
1787         unsigned                total;
1788         u32                     tag;
1789         char                    *kbuf;
1790
1791         spin_lock_irq(&dev->lock);
1792         if (dev->state > STATE_DEV_OPENED) {
1793                 value = ep0_write(fd, buf, len, ptr);
1794                 spin_unlock_irq(&dev->lock);
1795                 return value;
1796         }
1797         spin_unlock_irq(&dev->lock);
1798
1799         if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1800             (len > PAGE_SIZE * 4))
1801                 return -EINVAL;
1802
1803         /* we might need to change message format someday */
1804         if (copy_from_user (&tag, buf, 4))
1805                 return -EFAULT;
1806         if (tag != 0)
1807                 return -EINVAL;
1808         buf += 4;
1809         length -= 4;
1810
1811         kbuf = memdup_user(buf, length);
1812         if (IS_ERR(kbuf))
1813                 return PTR_ERR(kbuf);
1814
1815         spin_lock_irq (&dev->lock);
1816         value = -EINVAL;
1817         if (dev->buf) {
1818                 kfree(kbuf);
1819                 goto fail;
1820         }
1821         dev->buf = kbuf;
1822
1823         /* full or low speed config */
1824         dev->config = (void *) kbuf;
1825         total = le16_to_cpu(dev->config->wTotalLength);
1826         if (!is_valid_config(dev->config, total) ||
1827                         total > length - USB_DT_DEVICE_SIZE)
1828                 goto fail;
1829         kbuf += total;
1830         length -= total;
1831
1832         /* optional high speed config */
1833         if (kbuf [1] == USB_DT_CONFIG) {
1834                 dev->hs_config = (void *) kbuf;
1835                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1836                 if (!is_valid_config(dev->hs_config, total) ||
1837                                 total > length - USB_DT_DEVICE_SIZE)
1838                         goto fail;
1839                 kbuf += total;
1840                 length -= total;
1841         } else {
1842                 dev->hs_config = NULL;
1843         }
1844
1845         /* could support multiple configs, using another encoding! */
1846
1847         /* device descriptor (tweaked for paranoia) */
1848         if (length != USB_DT_DEVICE_SIZE)
1849                 goto fail;
1850         dev->dev = (void *)kbuf;
1851         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1852                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1853                         || dev->dev->bNumConfigurations != 1)
1854                 goto fail;
1855         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1856
1857         /* triggers gadgetfs_bind(); then we can enumerate. */
1858         spin_unlock_irq (&dev->lock);
1859         if (dev->hs_config)
1860                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1861         else
1862                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1863
1864         value = usb_gadget_probe_driver(&gadgetfs_driver);
1865         if (value != 0) {
1866                 kfree (dev->buf);
1867                 dev->buf = NULL;
1868         } else {
1869                 /* at this point "good" hardware has for the first time
1870                  * let the USB the host see us.  alternatively, if users
1871                  * unplug/replug that will clear all the error state.
1872                  *
1873                  * note:  everything running before here was guaranteed
1874                  * to choke driver model style diagnostics.  from here
1875                  * on, they can work ... except in cleanup paths that
1876                  * kick in after the ep0 descriptor is closed.
1877                  */
1878                 value = len;
1879                 dev->gadget_registered = true;
1880         }
1881         return value;
1882
1883 fail:
1884         spin_unlock_irq (&dev->lock);
1885         pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev);
1886         kfree (dev->buf);
1887         dev->buf = NULL;
1888         return value;
1889 }
1890
1891 static int
1892 dev_open (struct inode *inode, struct file *fd)
1893 {
1894         struct dev_data         *dev = inode->i_private;
1895         int                     value = -EBUSY;
1896
1897         spin_lock_irq(&dev->lock);
1898         if (dev->state == STATE_DEV_DISABLED) {
1899                 dev->ev_next = 0;
1900                 dev->state = STATE_DEV_OPENED;
1901                 fd->private_data = dev;
1902                 get_dev (dev);
1903                 value = 0;
1904         }
1905         spin_unlock_irq(&dev->lock);
1906         return value;
1907 }
1908
1909 static const struct file_operations ep0_operations = {
1910         .llseek =       no_llseek,
1911
1912         .open =         dev_open,
1913         .read =         ep0_read,
1914         .write =        dev_config,
1915         .fasync =       ep0_fasync,
1916         .poll =         ep0_poll,
1917         .unlocked_ioctl = dev_ioctl,
1918         .release =      dev_release,
1919 };
1920
1921 /*----------------------------------------------------------------------*/
1922
1923 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1924  *
1925  * Mounting the filesystem creates a controller file, used first for
1926  * device configuration then later for event monitoring.
1927  */
1928
1929
1930 /* FIXME PAM etc could set this security policy without mount options
1931  * if epfiles inherited ownership and permissons from ep0 ...
1932  */
1933
1934 static unsigned default_uid;
1935 static unsigned default_gid;
1936 static unsigned default_perm = S_IRUSR | S_IWUSR;
1937
1938 module_param (default_uid, uint, 0644);
1939 module_param (default_gid, uint, 0644);
1940 module_param (default_perm, uint, 0644);
1941
1942
1943 static struct inode *
1944 gadgetfs_make_inode (struct super_block *sb,
1945                 void *data, const struct file_operations *fops,
1946                 int mode)
1947 {
1948         struct inode *inode = new_inode (sb);
1949
1950         if (inode) {
1951                 inode->i_ino = get_next_ino();
1952                 inode->i_mode = mode;
1953                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
1954                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
1955                 inode->i_atime = inode->i_mtime = inode->i_ctime
1956                                 = current_time(inode);
1957                 inode->i_private = data;
1958                 inode->i_fop = fops;
1959         }
1960         return inode;
1961 }
1962
1963 /* creates in fs root directory, so non-renamable and non-linkable.
1964  * so inode and dentry are paired, until device reconfig.
1965  */
1966 static struct dentry *
1967 gadgetfs_create_file (struct super_block *sb, char const *name,
1968                 void *data, const struct file_operations *fops)
1969 {
1970         struct dentry   *dentry;
1971         struct inode    *inode;
1972
1973         dentry = d_alloc_name(sb->s_root, name);
1974         if (!dentry)
1975                 return NULL;
1976
1977         inode = gadgetfs_make_inode (sb, data, fops,
1978                         S_IFREG | (default_perm & S_IRWXUGO));
1979         if (!inode) {
1980                 dput(dentry);
1981                 return NULL;
1982         }
1983         d_add (dentry, inode);
1984         return dentry;
1985 }
1986
1987 static const struct super_operations gadget_fs_operations = {
1988         .statfs =       simple_statfs,
1989         .drop_inode =   generic_delete_inode,
1990 };
1991
1992 static int
1993 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
1994 {
1995         struct inode    *inode;
1996         struct dev_data *dev;
1997
1998         if (the_device)
1999                 return -ESRCH;
2000
2001         CHIP = usb_get_gadget_udc_name();
2002         if (!CHIP)
2003                 return -ENODEV;
2004
2005         /* superblock */
2006         sb->s_blocksize = PAGE_SIZE;
2007         sb->s_blocksize_bits = PAGE_SHIFT;
2008         sb->s_magic = GADGETFS_MAGIC;
2009         sb->s_op = &gadget_fs_operations;
2010         sb->s_time_gran = 1;
2011
2012         /* root inode */
2013         inode = gadgetfs_make_inode (sb,
2014                         NULL, &simple_dir_operations,
2015                         S_IFDIR | S_IRUGO | S_IXUGO);
2016         if (!inode)
2017                 goto Enomem;
2018         inode->i_op = &simple_dir_inode_operations;
2019         if (!(sb->s_root = d_make_root (inode)))
2020                 goto Enomem;
2021
2022         /* the ep0 file is named after the controller we expect;
2023          * user mode code can use it for sanity checks, like we do.
2024          */
2025         dev = dev_new ();
2026         if (!dev)
2027                 goto Enomem;
2028
2029         dev->sb = sb;
2030         dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2031         if (!dev->dentry) {
2032                 put_dev(dev);
2033                 goto Enomem;
2034         }
2035
2036         /* other endpoint files are available after hardware setup,
2037          * from binding to a controller.
2038          */
2039         the_device = dev;
2040         return 0;
2041
2042 Enomem:
2043         return -ENOMEM;
2044 }
2045
2046 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2047 static struct dentry *
2048 gadgetfs_mount (struct file_system_type *t, int flags,
2049                 const char *path, void *opts)
2050 {
2051         return mount_single (t, flags, opts, gadgetfs_fill_super);
2052 }
2053
2054 static void
2055 gadgetfs_kill_sb (struct super_block *sb)
2056 {
2057         kill_litter_super (sb);
2058         if (the_device) {
2059                 put_dev (the_device);
2060                 the_device = NULL;
2061         }
2062         kfree(CHIP);
2063         CHIP = NULL;
2064 }
2065
2066 /*----------------------------------------------------------------------*/
2067
2068 static struct file_system_type gadgetfs_type = {
2069         .owner          = THIS_MODULE,
2070         .name           = shortname,
2071         .mount          = gadgetfs_mount,
2072         .kill_sb        = gadgetfs_kill_sb,
2073 };
2074 MODULE_ALIAS_FS("gadgetfs");
2075
2076 /*----------------------------------------------------------------------*/
2077
2078 static int __init init (void)
2079 {
2080         int status;
2081
2082         status = register_filesystem (&gadgetfs_type);
2083         if (status == 0)
2084                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2085                         shortname, driver_desc);
2086         return status;
2087 }
2088 module_init (init);
2089
2090 static void __exit cleanup (void)
2091 {
2092         pr_debug ("unregister %s\n", shortname);
2093         unregister_filesystem (&gadgetfs_type);
2094 }
2095 module_exit (cleanup);
2096