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 <linux/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 #include <linux/refcount.h>
  31 #include <linux/delay.h>
  32 #include <linux/device.h>
  33 #include <linux/moduleparam.h>
  34
  35 #include <linux/usb/gadgetfs.h>
  36 #include <linux/usb/gadget.h>
  37
  38
  39 /*
  40  * The gadgetfs API maps each endpoint to a file descriptor so that you
  41  * can use standard synchronous read/write calls for I/O.  There's some
  42  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  43  * drivers show how this works in practice.  You can also use AIO to
  44  * eliminate I/O gaps between requests, to help when streaming data.
  45  *
  46  * Key parts that must be USB-specific are protocols defining how the
  47  * read/write operations relate to the hardware state machines.  There
  48  * are two types of files.  One type is for the device, implementing ep0.
  49  * The other type is for each IN or OUT endpoint.  In both cases, the
  50  * user mode driver must configure the hardware before using it.
  51  *
  52  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  53  *   (by writing configuration and device descriptors).  Afterwards it
  54  *   may serve as a source of device events, used to handle all control
  55  *   requests other than basic enumeration.
  56  *
  57  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  58  *   called when each /dev/gadget/ep* file is configured (by writing
  59  *   endpoint descriptors).  Afterwards these files are used to write()
  60  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  61  *   direction" request is issued (like reading an IN endpoint).
  62  *
  63  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  64  * not possible on all hardware.  For example, precise fault handling with
  65  * respect to data left in endpoint fifos after aborted operations; or
  66  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  67  */
  68
  69 #define DRIVER_DESC     "USB Gadget filesystem"
  70 #define DRIVER_VERSION  "24 Aug 2004"
  71
  72 static const char driver_desc [] = DRIVER_DESC;
  73 static const char shortname [] = "gadgetfs";
  74
  75 MODULE_DESCRIPTION (DRIVER_DESC);
  76 MODULE_AUTHOR ("David Brownell");
  77 MODULE_LICENSE ("GPL");
  78
  79 static int ep_open(struct inode *, struct file *);
  80
  81
  82 /*----------------------------------------------------------------------*/
  83
  84 #define GADGETFS_MAGIC          0xaee71ee7
  85
  86 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  87 enum ep0_state {
  88         /* DISABLED is the initial state. */
  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 #define RBUF_SIZE               256
 117
 118 struct dev_data {
 119         spinlock_t                      lock;
 120         refcount_t                      count;
 121         int                             udc_usage;
 122         enum ep0_state                  state;          /* P: lock */
 123         struct usb_gadgetfs_event       event [N_EVENT];
 124         unsigned                        ev_next;
 125         struct fasync_struct            *fasync;
 126         u8                              current_config;
 127
 128         /* drivers reading ep0 MUST handle control requests (SETUP)
 129          * reported that way; else the host will time out.
 130          */
 131         unsigned                        usermode_setup : 1,
 132                                         setup_in : 1,
 133                                         setup_can_stall : 1,
 134                                         setup_out_ready : 1,
 135                                         setup_out_error : 1,
 136                                         setup_abort : 1,
 137                                         gadget_registered : 1;
 138         unsigned                        setup_wLength;
 139
 140         /* the rest is basically write-once */
 141         struct usb_config_descriptor    *config, *hs_config;
 142         struct usb_device_descriptor    *dev;
 143         struct usb_request              *req;
 144         struct usb_gadget               *gadget;
 145         struct list_head                epfiles;
 146         void                            *buf;
 147         wait_queue_head_t               wait;
 148         struct super_block              *sb;
 149         struct dentry                   *dentry;
 150
 151         /* except this scratch i/o buffer for ep0 */
 152         u8                              rbuf[RBUF_SIZE];
 153 };
 154
 155 static inline void get_dev (struct dev_data *data)
 156 {
 157         refcount_inc (&data->count);
 158 }
 159
 160 static void put_dev (struct dev_data *data)
 161 {
 162         if (likely (!refcount_dec_and_test (&data->count)))
 163                 return;
 164         /* needs no more cleanup */
 165         BUG_ON (waitqueue_active (&data->wait));
 166         kfree (data);
 167 }
 168
 169 static struct dev_data *dev_new (void)
 170 {
 171         struct dev_data         *dev;
 172
 173         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 174         if (!dev)
 175                 return NULL;
 176         dev->state = STATE_DEV_DISABLED;
 177         refcount_set (&dev->count, 1);
 178         spin_lock_init (&dev->lock);
 179         INIT_LIST_HEAD (&dev->epfiles);
 180         init_waitqueue_head (&dev->wait);
 181         return dev;
 182 }
 183
 184 /*----------------------------------------------------------------------*/
 185
 186 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 187 enum ep_state {
 188         STATE_EP_DISABLED = 0,
 189         STATE_EP_READY,
 190         STATE_EP_ENABLED,
 191         STATE_EP_UNBOUND,
 192 };
 193
 194 struct ep_data {
 195         struct mutex                    lock;
 196         enum ep_state                   state;
 197         refcount_t                      count;
 198         struct dev_data                 *dev;
 199         /* must hold dev->lock before accessing ep or req */
 200         struct usb_ep                   *ep;
 201         struct usb_request              *req;
 202         ssize_t                         status;
 203         char                            name [16];
 204         struct usb_endpoint_descriptor  desc, hs_desc;
 205         struct list_head                epfiles;
 206         wait_queue_head_t               wait;
 207         struct dentry                   *dentry;
 208 };
 209
 210 static inline void get_ep (struct ep_data *data)
 211 {
 212         refcount_inc (&data->count);
 213 }
 214
 215 static void put_ep (struct ep_data *data)
 216 {
 217         if (likely (!refcount_dec_and_test (&data->count)))
 218                 return;
 219         put_dev (data->dev);
 220         /* needs no more cleanup */
 221         BUG_ON (!list_empty (&data->epfiles));
 222         BUG_ON (waitqueue_active (&data->wait));
 223         kfree (data);
 224 }
 225
 226 /*----------------------------------------------------------------------*/
 227
 228 /* most "how to use the hardware" policy choices are in userspace:
 229  * mapping endpoint roles (which the driver needs) to the capabilities
 230  * which the usb controller has.  most of those capabilities are exposed
 231  * implicitly, starting with the driver name and then endpoint names.
 232  */
 233
 234 static const char *CHIP;
 235
 236 /*----------------------------------------------------------------------*/
 237
 238 /* NOTE:  don't use dev_printk calls before binding to the gadget
 239  * at the end of ep0 configuration, or after unbind.
 240  */
 241
 242 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 243 #define xprintk(d,level,fmt,args...) \
 244         printk(level "%s: " fmt , shortname , ## args)
 245
 246 #ifdef DEBUG
 247 #define DBG(dev,fmt,args...) \
 248         xprintk(dev , KERN_DEBUG , fmt , ## args)
 249 #else
 250 #define DBG(dev,fmt,args...) \
 251         do { } while (0)
 252 #endif /* DEBUG */
 253
 254 #ifdef VERBOSE_DEBUG
 255 #define VDEBUG  DBG
 256 #else
 257 #define VDEBUG(dev,fmt,args...) \
 258         do { } while (0)
 259 #endif /* DEBUG */
 260
 261 #define ERROR(dev,fmt,args...) \
 262         xprintk(dev , KERN_ERR , fmt , ## args)
 263 #define INFO(dev,fmt,args...) \
 264         xprintk(dev , KERN_INFO , fmt , ## args)
 265
 266
 267 /*----------------------------------------------------------------------*/
 268
 269 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 270  *
 271  * After opening, configure non-control endpoints.  Then use normal
 272  * stream read() and write() requests; and maybe ioctl() to get more
 273  * precise FIFO status when recovering from cancellation.
 274  */
 275
 276 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 277 {
 278         struct ep_data  *epdata = ep->driver_data;
 279
 280         if (!req->context)
 281                 return;
 282         if (req->status)
 283                 epdata->status = req->status;
 284         else
 285                 epdata->status = req->actual;
 286         complete ((struct completion *)req->context);
 287 }
 288
 289 /* tasklock endpoint, returning when it's connected.
 290  * still need dev->lock to use epdata->ep.
 291  */
 292 static int
 293 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 294 {
 295         int     val;
 296
 297         if (f_flags & O_NONBLOCK) {
 298                 if (!mutex_trylock(&epdata->lock))
 299                         goto nonblock;
 300                 if (epdata->state != STATE_EP_ENABLED &&
 301                     (!is_write || epdata->state != STATE_EP_READY)) {
 302                         mutex_unlock(&epdata->lock);
 303 nonblock:
 304                         val = -EAGAIN;
 305                 } else
 306                         val = 0;
 307                 return val;
 308         }
 309
 310         val = mutex_lock_interruptible(&epdata->lock);
 311         if (val < 0)
 312                 return val;
 313
 314         switch (epdata->state) {
 315         case STATE_EP_ENABLED:
 316                 return 0;
 317         case STATE_EP_READY:                    /* not configured yet */
 318                 if (is_write)
 319                         return 0;
 320                 // FALLTHRU
 321         case STATE_EP_UNBOUND:                  /* clean disconnect */
 322                 break;
 323         // case STATE_EP_DISABLED:              /* "can't happen" */
 324         default:                                /* error! */
 325                 pr_debug ("%s: ep %p not available, state %d\n",
 326                                 shortname, epdata, epdata->state);
 327         }
 328         mutex_unlock(&epdata->lock);
 329         return -ENODEV;
 330 }
 331
 332 static ssize_t
 333 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 334 {
 335         DECLARE_COMPLETION_ONSTACK (done);
 336         int value;
 337
 338         spin_lock_irq (&epdata->dev->lock);
 339         if (likely (epdata->ep != NULL)) {
 340                 struct usb_request      *req = epdata->req;
 341
 342                 req->context = &done;
 343                 req->complete = epio_complete;
 344                 req->buf = buf;
 345                 req->length = len;
 346                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 347         } else
 348                 value = -ENODEV;
 349         spin_unlock_irq (&epdata->dev->lock);
 350
 351         if (likely (value == 0)) {
 352                 value = wait_event_interruptible (done.wait, done.done);
 353                 if (value != 0) {
 354                         spin_lock_irq (&epdata->dev->lock);
 355                         if (likely (epdata->ep != NULL)) {
 356                                 DBG (epdata->dev, "%s i/o interrupted\n",
 357                                                 epdata->name);
 358                                 usb_ep_dequeue (epdata->ep, epdata->req);
 359                                 spin_unlock_irq (&epdata->dev->lock);
 360
 361                                 wait_event (done.wait, done.done);
 362                                 if (epdata->status == -ECONNRESET)
 363                                         epdata->status = -EINTR;
 364                         } else {
 365                                 spin_unlock_irq (&epdata->dev->lock);
 366
 367                                 DBG (epdata->dev, "endpoint gone\n");
 368                                 epdata->status = -ENODEV;
 369                         }
 370                 }
 371                 return epdata->status;
 372         }
 373         return value;
 374 }
 375
 376 static int
 377 ep_release (struct inode *inode, struct file *fd)
 378 {
 379         struct ep_data          *data = fd->private_data;
 380         int value;
 381
 382         value = mutex_lock_interruptible(&data->lock);
 383         if (value < 0)
 384                 return value;
 385
 386         /* clean up if this can be reopened */
 387         if (data->state != STATE_EP_UNBOUND) {
 388                 data->state = STATE_EP_DISABLED;
 389                 data->desc.bDescriptorType = 0;
 390                 data->hs_desc.bDescriptorType = 0;
 391                 usb_ep_disable(data->ep);
 392         }
 393         mutex_unlock(&data->lock);
 394         put_ep (data);
 395         return 0;
 396 }
 397
 398 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 399 {
 400         struct ep_data          *data = fd->private_data;
 401         int                     status;
 402
 403         if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
 404                 return status;
 405
 406         spin_lock_irq (&data->dev->lock);
 407         if (likely (data->ep != NULL)) {
 408                 switch (code) {
 409                 case GADGETFS_FIFO_STATUS:
 410                         status = usb_ep_fifo_status (data->ep);
 411                         break;
 412                 case GADGETFS_FIFO_FLUSH:
 413                         usb_ep_fifo_flush (data->ep);
 414                         break;
 415                 case GADGETFS_CLEAR_HALT:
 416                         status = usb_ep_clear_halt (data->ep);
 417                         break;
 418                 default:
 419                         status = -ENOTTY;
 420                 }
 421         } else
 422                 status = -ENODEV;
 423         spin_unlock_irq (&data->dev->lock);
 424         mutex_unlock(&data->lock);
 425         return status;
 426 }
 427
 428 /*----------------------------------------------------------------------*/
 429
 430 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 431
 432 struct kiocb_priv {
 433         struct usb_request      *req;
 434         struct ep_data          *epdata;
 435         struct kiocb            *iocb;
 436         struct mm_struct        *mm;
 437         struct work_struct      work;
 438         void                    *buf;
 439         struct iov_iter         to;
 440         const void              *to_free;
 441         unsigned                actual;
 442 };
 443
 444 static int ep_aio_cancel(struct kiocb *iocb)
 445 {
 446         struct kiocb_priv       *priv = iocb->private;
 447         struct ep_data          *epdata;
 448         int                     value;
 449
 450         local_irq_disable();
 451         epdata = priv->epdata;
 452         // spin_lock(&epdata->dev->lock);
 453         if (likely(epdata && epdata->ep && priv->req))
 454                 value = usb_ep_dequeue (epdata->ep, priv->req);
 455         else
 456                 value = -EINVAL;
 457         // spin_unlock(&epdata->dev->lock);
 458         local_irq_enable();
 459
 460         return value;
 461 }
 462
 463 static void ep_user_copy_worker(struct work_struct *work)
 464 {
 465         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 466         struct mm_struct *mm = priv->mm;
 467         struct kiocb *iocb = priv->iocb;
 468         size_t ret;
 469
 470         use_mm(mm);
 471         ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
 472         unuse_mm(mm);
 473         if (!ret)
 474                 ret = -EFAULT;
 475
 476         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 477         iocb->ki_complete(iocb, ret, ret);
 478
 479         kfree(priv->buf);
 480         kfree(priv->to_free);
 481         kfree(priv);
 482 }
 483
 484 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 485 {
 486         struct kiocb            *iocb = req->context;
 487         struct kiocb_priv       *priv = iocb->private;
 488         struct ep_data          *epdata = priv->epdata;
 489
 490         /* lock against disconnect (and ideally, cancel) */
 491         spin_lock(&epdata->dev->lock);
 492         priv->req = NULL;
 493         priv->epdata = NULL;
 494
 495         /* if this was a write or a read returning no data then we
 496          * don't need to copy anything to userspace, so we can
 497          * complete the aio request immediately.
 498          */
 499         if (priv->to_free == NULL || unlikely(req->actual == 0)) {
 500                 kfree(req->buf);
 501                 kfree(priv->to_free);
 502                 kfree(priv);
 503                 iocb->private = NULL;
 504                 /* aio_complete() reports bytes-transferred _and_ faults */
 505
 506                 iocb->ki_complete(iocb, req->actual ? req->actual : req->status,
 507                                 req->status);
 508         } else {
 509                 /* ep_copy_to_user() won't report both; we hide some faults */
 510                 if (unlikely(0 != req->status))
 511                         DBG(epdata->dev, "%s fault %d len %d\n",
 512                                 ep->name, req->status, req->actual);
 513
 514                 priv->buf = req->buf;
 515                 priv->actual = req->actual;
 516                 INIT_WORK(&priv->work, ep_user_copy_worker);
 517                 schedule_work(&priv->work);
 518         }
 519
 520         usb_ep_free_request(ep, req);
 521         spin_unlock(&epdata->dev->lock);
 522         put_ep(epdata);
 523 }
 524
 525 static ssize_t ep_aio(struct kiocb *iocb,
 526                       struct kiocb_priv *priv,
 527                       struct ep_data *epdata,
 528                       char *buf,
 529                       size_t len)
 530 {
 531         struct usb_request *req;
 532         ssize_t value;
 533
 534         iocb->private = priv;
 535         priv->iocb = iocb;
 536
 537         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 538         get_ep(epdata);
 539         priv->epdata = epdata;
 540         priv->actual = 0;
 541         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 542
 543         /* each kiocb is coupled to one usb_request, but we can't
 544          * allocate or submit those if the host disconnected.
 545          */
 546         spin_lock_irq(&epdata->dev->lock);
 547         value = -ENODEV;
 548         if (unlikely(epdata->ep == NULL))
 549                 goto fail;
 550
 551         req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 552         value = -ENOMEM;
 553         if (unlikely(!req))
 554                 goto fail;
 555
 556         priv->req = req;
 557         req->buf = buf;
 558         req->length = len;
 559         req->complete = ep_aio_complete;
 560         req->context = iocb;
 561         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 562         if (unlikely(0 != value)) {
 563                 usb_ep_free_request(epdata->ep, req);
 564                 goto fail;
 565         }
 566         spin_unlock_irq(&epdata->dev->lock);
 567         return -EIOCBQUEUED;
 568
 569 fail:
 570         spin_unlock_irq(&epdata->dev->lock);
 571         kfree(priv->to_free);
 572         kfree(priv);
 573         put_ep(epdata);
 574         return value;
 575 }
 576
 577 static ssize_t
 578 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 579 {
 580         struct file *file = iocb->ki_filp;
 581         struct ep_data *epdata = file->private_data;
 582         size_t len = iov_iter_count(to);
 583         ssize_t value;
 584         char *buf;
 585
 586         if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
 587                 return value;
 588
 589         /* halt any endpoint by doing a "wrong direction" i/o call */
 590         if (usb_endpoint_dir_in(&epdata->desc)) {
 591                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 592                     !is_sync_kiocb(iocb)) {
 593                         mutex_unlock(&epdata->lock);
 594                         return -EINVAL;
 595                 }
 596                 DBG (epdata->dev, "%s halt\n", epdata->name);
 597                 spin_lock_irq(&epdata->dev->lock);
 598                 if (likely(epdata->ep != NULL))
 599                         usb_ep_set_halt(epdata->ep);
 600                 spin_unlock_irq(&epdata->dev->lock);
 601                 mutex_unlock(&epdata->lock);
 602                 return -EBADMSG;
 603         }
 604
 605         buf = kmalloc(len, GFP_KERNEL);
 606         if (unlikely(!buf)) {
 607                 mutex_unlock(&epdata->lock);
 608                 return -ENOMEM;
 609         }
 610         if (is_sync_kiocb(iocb)) {
 611                 value = ep_io(epdata, buf, len);
 612                 if (value >= 0 && (copy_to_iter(buf, value, to) != value))
 613                         value = -EFAULT;
 614         } else {
 615                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 616                 value = -ENOMEM;
 617                 if (!priv)
 618                         goto fail;
 619                 priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
 620                 if (!priv->to_free) {
 621                         kfree(priv);
 622                         goto fail;
 623                 }
 624                 value = ep_aio(iocb, priv, epdata, buf, len);
 625                 if (value == -EIOCBQUEUED)
 626                         buf = NULL;
 627         }
 628 fail:
 629         kfree(buf);
 630         mutex_unlock(&epdata->lock);
 631         return value;
 632 }
 633
 634 static ssize_t ep_config(struct ep_data *, const char *, size_t);
 635
 636 static ssize_t
 637 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 638 {
 639         struct file *file = iocb->ki_filp;
 640         struct ep_data *epdata = file->private_data;
 641         size_t len = iov_iter_count(from);
 642         bool configured;
 643         ssize_t value;
 644         char *buf;
 645
 646         if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
 647                 return value;
 648
 649         configured = epdata->state == STATE_EP_ENABLED;
 650
 651         /* halt any endpoint by doing a "wrong direction" i/o call */
 652         if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
 653                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 654                     !is_sync_kiocb(iocb)) {
 655                         mutex_unlock(&epdata->lock);
 656                         return -EINVAL;
 657                 }
 658                 DBG (epdata->dev, "%s halt\n", epdata->name);
 659                 spin_lock_irq(&epdata->dev->lock);
 660                 if (likely(epdata->ep != NULL))
 661                         usb_ep_set_halt(epdata->ep);
 662                 spin_unlock_irq(&epdata->dev->lock);
 663                 mutex_unlock(&epdata->lock);
 664                 return -EBADMSG;
 665         }
 666
 667         buf = kmalloc(len, GFP_KERNEL);
 668         if (unlikely(!buf)) {
 669                 mutex_unlock(&epdata->lock);
 670                 return -ENOMEM;
 671         }
 672
 673         if (unlikely(!copy_from_iter_full(buf, len, from))) {
 674                 value = -EFAULT;
 675                 goto out;
 676         }
 677
 678         if (unlikely(!configured)) {
 679                 value = ep_config(epdata, buf, len);
 680         } else if (is_sync_kiocb(iocb)) {
 681                 value = ep_io(epdata, buf, len);
 682         } else {
 683                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 684                 value = -ENOMEM;
 685                 if (priv) {
 686                         value = ep_aio(iocb, priv, epdata, buf, len);
 687                         if (value == -EIOCBQUEUED)
 688                                 buf = NULL;
 689                 }
 690         }
 691 out:
 692         kfree(buf);
 693         mutex_unlock(&epdata->lock);
 694         return value;
 695 }
 696
 697 /*----------------------------------------------------------------------*/
 698
 699 /* used after endpoint configuration */
 700 static const struct file_operations ep_io_operations = {
 701         .owner =        THIS_MODULE,
 702
 703         .open =         ep_open,
 704         .release =      ep_release,
 705         .llseek =       no_llseek,
 706         .unlocked_ioctl = ep_ioctl,
 707         .read_iter =    ep_read_iter,
 708         .write_iter =   ep_write_iter,
 709 };
 710
 711 /* ENDPOINT INITIALIZATION
 712  *
 713  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 714  *     status = write (fd, descriptors, sizeof descriptors)
 715  *
 716  * That write establishes the endpoint configuration, configuring
 717  * the controller to process bulk, interrupt, or isochronous transfers
 718  * at the right maxpacket size, and so on.
 719  *
 720  * The descriptors are message type 1, identified by a host order u32
 721  * at the beginning of what's written.  Descriptor order is: full/low
 722  * speed descriptor, then optional high speed descriptor.
 723  */
 724 static ssize_t
 725 ep_config (struct ep_data *data, const char *buf, size_t len)
 726 {
 727         struct usb_ep           *ep;
 728         u32                     tag;
 729         int                     value, length = len;
 730
 731         if (data->state != STATE_EP_READY) {
 732                 value = -EL2HLT;
 733                 goto fail;
 734         }
 735
 736         value = len;
 737         if (len < USB_DT_ENDPOINT_SIZE + 4)
 738                 goto fail0;
 739
 740         /* we might need to change message format someday */
 741         memcpy(&tag, buf, 4);
 742         if (tag != 1) {
 743                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 744                 goto fail0;
 745         }
 746         buf += 4;
 747         len -= 4;
 748
 749         /* NOTE:  audio endpoint extensions not accepted here;
 750          * just don't include the extra bytes.
 751          */
 752
 753         /* full/low speed descriptor, then high speed */
 754         memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
 755         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 756                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 757                 goto fail0;
 758         if (len != USB_DT_ENDPOINT_SIZE) {
 759                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 760                         goto fail0;
 761                 memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 762                         USB_DT_ENDPOINT_SIZE);
 763                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 764                                 || data->hs_desc.bDescriptorType
 765                                         != USB_DT_ENDPOINT) {
 766                         DBG(data->dev, "config %s, bad hs length or type\n",
 767                                         data->name);
 768                         goto fail0;
 769                 }
 770         }
 771
 772         spin_lock_irq (&data->dev->lock);
 773         if (data->dev->state == STATE_DEV_UNBOUND) {
 774                 value = -ENOENT;
 775                 goto gone;
 776         } else {
 777                 ep = data->ep;
 778                 if (ep == NULL) {
 779                         value = -ENODEV;
 780                         goto gone;
 781                 }
 782         }
 783         switch (data->dev->gadget->speed) {
 784         case USB_SPEED_LOW:
 785         case USB_SPEED_FULL:
 786                 ep->desc = &data->desc;
 787                 break;
 788         case USB_SPEED_HIGH:
 789                 /* fails if caller didn't provide that descriptor... */
 790                 ep->desc = &data->hs_desc;
 791                 break;
 792         default:
 793                 DBG(data->dev, "unconnected, %s init abandoned\n",
 794                                 data->name);
 795                 value = -EINVAL;
 796                 goto gone;
 797         }
 798         value = usb_ep_enable(ep);
 799         if (value == 0) {
 800                 data->state = STATE_EP_ENABLED;
 801                 value = length;
 802         }
 803 gone:
 804         spin_unlock_irq (&data->dev->lock);
 805         if (value < 0) {
 806 fail:
 807                 data->desc.bDescriptorType = 0;
 808                 data->hs_desc.bDescriptorType = 0;
 809         }
 810         return value;
 811 fail0:
 812         value = -EINVAL;
 813         goto fail;
 814 }
 815
 816 static int
 817 ep_open (struct inode *inode, struct file *fd)
 818 {
 819         struct ep_data          *data = inode->i_private;
 820         int                     value = -EBUSY;
 821
 822         if (mutex_lock_interruptible(&data->lock) != 0)
 823                 return -EINTR;
 824         spin_lock_irq (&data->dev->lock);
 825         if (data->dev->state == STATE_DEV_UNBOUND)
 826                 value = -ENOENT;
 827         else if (data->state == STATE_EP_DISABLED) {
 828                 value = 0;
 829                 data->state = STATE_EP_READY;
 830                 get_ep (data);
 831                 fd->private_data = data;
 832                 VDEBUG (data->dev, "%s ready\n", data->name);
 833         } else
 834                 DBG (data->dev, "%s state %d\n",
 835                         data->name, data->state);
 836         spin_unlock_irq (&data->dev->lock);
 837         mutex_unlock(&data->lock);
 838         return value;
 839 }
 840
 841 /*----------------------------------------------------------------------*/
 842
 843 /* EP0 IMPLEMENTATION can be partly in userspace.
 844  *
 845  * Drivers that use this facility receive various events, including
 846  * control requests the kernel doesn't handle.  Drivers that don't
 847  * use this facility may be too simple-minded for real applications.
 848  */
 849
 850 static inline void ep0_readable (struct dev_data *dev)
 851 {
 852         wake_up (&dev->wait);
 853         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 854 }
 855
 856 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 857 {
 858         struct dev_data         *dev = ep->driver_data;
 859
 860         if (req->buf != dev->rbuf) {
 861                 kfree(req->buf);
 862                 req->buf = dev->rbuf;
 863         }
 864         req->complete = epio_complete;
 865         dev->setup_out_ready = 0;
 866 }
 867
 868 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 869 {
 870         struct dev_data         *dev = ep->driver_data;
 871         unsigned long           flags;
 872         int                     free = 1;
 873
 874         /* for control OUT, data must still get to userspace */
 875         spin_lock_irqsave(&dev->lock, flags);
 876         if (!dev->setup_in) {
 877                 dev->setup_out_error = (req->status != 0);
 878                 if (!dev->setup_out_error)
 879                         free = 0;
 880                 dev->setup_out_ready = 1;
 881                 ep0_readable (dev);
 882         }
 883
 884         /* clean up as appropriate */
 885         if (free && req->buf != &dev->rbuf)
 886                 clean_req (ep, req);
 887         req->complete = epio_complete;
 888         spin_unlock_irqrestore(&dev->lock, flags);
 889 }
 890
 891 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 892 {
 893         struct dev_data *dev = ep->driver_data;
 894
 895         if (dev->setup_out_ready) {
 896                 DBG (dev, "ep0 request busy!\n");
 897                 return -EBUSY;
 898         }
 899         if (len > sizeof (dev->rbuf))
 900                 req->buf = kmalloc(len, GFP_ATOMIC);
 901         if (req->buf == NULL) {
 902                 req->buf = dev->rbuf;
 903                 return -ENOMEM;
 904         }
 905         req->complete = ep0_complete;
 906         req->length = len;
 907         req->zero = 0;
 908         return 0;
 909 }
 910
 911 static ssize_t
 912 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 913 {
 914         struct dev_data                 *dev = fd->private_data;
 915         ssize_t                         retval;
 916         enum ep0_state                  state;
 917
 918         spin_lock_irq (&dev->lock);
 919         if (dev->state <= STATE_DEV_OPENED) {
 920                 retval = -EINVAL;
 921                 goto done;
 922         }
 923
 924         /* report fd mode change before acting on it */
 925         if (dev->setup_abort) {
 926                 dev->setup_abort = 0;
 927                 retval = -EIDRM;
 928                 goto done;
 929         }
 930
 931         /* control DATA stage */
 932         if ((state = dev->state) == STATE_DEV_SETUP) {
 933
 934                 if (dev->setup_in) {            /* stall IN */
 935                         VDEBUG(dev, "ep0in stall\n");
 936                         (void) usb_ep_set_halt (dev->gadget->ep0);
 937                         retval = -EL2HLT;
 938                         dev->state = STATE_DEV_CONNECTED;
 939
 940                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
 941                         struct usb_ep           *ep = dev->gadget->ep0;
 942                         struct usb_request      *req = dev->req;
 943
 944                         if ((retval = setup_req (ep, req, 0)) == 0) {
 945                                 ++dev->udc_usage;
 946                                 spin_unlock_irq (&dev->lock);
 947                                 retval = usb_ep_queue (ep, req, GFP_KERNEL);
 948                                 spin_lock_irq (&dev->lock);
 949                                 --dev->udc_usage;
 950                         }
 951                         dev->state = STATE_DEV_CONNECTED;
 952
 953                         /* assume that was SET_CONFIGURATION */
 954                         if (dev->current_config) {
 955                                 unsigned power;
 956
 957                                 if (gadget_is_dualspeed(dev->gadget)
 958                                                 && (dev->gadget->speed
 959                                                         == USB_SPEED_HIGH))
 960                                         power = dev->hs_config->bMaxPower;
 961                                 else
 962                                         power = dev->config->bMaxPower;
 963                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
 964                         }
 965
 966                 } else {                        /* collect OUT data */
 967                         if ((fd->f_flags & O_NONBLOCK) != 0
 968                                         && !dev->setup_out_ready) {
 969                                 retval = -EAGAIN;
 970                                 goto done;
 971                         }
 972                         spin_unlock_irq (&dev->lock);
 973                         retval = wait_event_interruptible (dev->wait,
 974                                         dev->setup_out_ready != 0);
 975
 976                         /* FIXME state could change from under us */
 977                         spin_lock_irq (&dev->lock);
 978                         if (retval)
 979                                 goto done;
 980
 981                         if (dev->state != STATE_DEV_SETUP) {
 982                                 retval = -ECANCELED;
 983                                 goto done;
 984                         }
 985                         dev->state = STATE_DEV_CONNECTED;
 986
 987                         if (dev->setup_out_error)
 988                                 retval = -EIO;
 989                         else {
 990                                 len = min (len, (size_t)dev->req->actual);
 991                                 ++dev->udc_usage;
 992                                 spin_unlock_irq(&dev->lock);
 993                                 if (copy_to_user (buf, dev->req->buf, len))
 994                                         retval = -EFAULT;
 995                                 else
 996                                         retval = len;
 997                                 spin_lock_irq(&dev->lock);
 998                                 --dev->udc_usage;
 999                                 clean_req (dev->gadget->ep0, dev->req);
1000                                 /* NOTE userspace can't yet choose to stall */
1001                         }
1002                 }
1003                 goto done;
1004         }
1005
1006         /* else normal: return event data */
1007         if (len < sizeof dev->event [0]) {
1008                 retval = -EINVAL;
1009                 goto done;
1010         }
1011         len -= len % sizeof (struct usb_gadgetfs_event);
1012         dev->usermode_setup = 1;
1013
1014 scan:
1015         /* return queued events right away */
1016         if (dev->ev_next != 0) {
1017                 unsigned                i, n;
1018
1019                 n = len / sizeof (struct usb_gadgetfs_event);
1020                 if (dev->ev_next < n)
1021                         n = dev->ev_next;
1022
1023                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1024                 for (i = 0; i < n; i++) {
1025                         if (dev->event [i].type == GADGETFS_SETUP) {
1026                                 dev->state = STATE_DEV_SETUP;
1027                                 n = i + 1;
1028                                 break;
1029                         }
1030                 }
1031                 spin_unlock_irq (&dev->lock);
1032                 len = n * sizeof (struct usb_gadgetfs_event);
1033                 if (copy_to_user (buf, &dev->event, len))
1034                         retval = -EFAULT;
1035                 else
1036                         retval = len;
1037                 if (len > 0) {
1038                         /* NOTE this doesn't guard against broken drivers;
1039                          * concurrent ep0 readers may lose events.
1040                          */
1041                         spin_lock_irq (&dev->lock);
1042                         if (dev->ev_next > n) {
1043                                 memmove(&dev->event[0], &dev->event[n],
1044                                         sizeof (struct usb_gadgetfs_event)
1045                                                 * (dev->ev_next - n));
1046                         }
1047                         dev->ev_next -= n;
1048                         spin_unlock_irq (&dev->lock);
1049                 }
1050                 return retval;
1051         }
1052         if (fd->f_flags & O_NONBLOCK) {
1053                 retval = -EAGAIN;
1054                 goto done;
1055         }
1056
1057         switch (state) {
1058         default:
1059                 DBG (dev, "fail %s, state %d\n", __func__, state);
1060                 retval = -ESRCH;
1061                 break;
1062         case STATE_DEV_UNCONNECTED:
1063         case STATE_DEV_CONNECTED:
1064                 spin_unlock_irq (&dev->lock);
1065                 DBG (dev, "%s wait\n", __func__);
1066
1067                 /* wait for events */
1068                 retval = wait_event_interruptible (dev->wait,
1069                                 dev->ev_next != 0);
1070                 if (retval < 0)
1071                         return retval;
1072                 spin_lock_irq (&dev->lock);
1073                 goto scan;
1074         }
1075
1076 done:
1077         spin_unlock_irq (&dev->lock);
1078         return retval;
1079 }
1080
1081 static struct usb_gadgetfs_event *
1082 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1083 {
1084         struct usb_gadgetfs_event       *event;
1085         unsigned                        i;
1086
1087         switch (type) {
1088         /* these events purge the queue */
1089         case GADGETFS_DISCONNECT:
1090                 if (dev->state == STATE_DEV_SETUP)
1091                         dev->setup_abort = 1;
1092                 // FALL THROUGH
1093         case GADGETFS_CONNECT:
1094                 dev->ev_next = 0;
1095                 break;
1096         case GADGETFS_SETUP:            /* previous request timed out */
1097         case GADGETFS_SUSPEND:          /* same effect */
1098                 /* these events can't be repeated */
1099                 for (i = 0; i != dev->ev_next; i++) {
1100                         if (dev->event [i].type != type)
1101                                 continue;
1102                         DBG(dev, "discard old event[%d] %d\n", i, type);
1103                         dev->ev_next--;
1104                         if (i == dev->ev_next)
1105                                 break;
1106                         /* indices start at zero, for simplicity */
1107                         memmove (&dev->event [i], &dev->event [i + 1],
1108                                 sizeof (struct usb_gadgetfs_event)
1109                                         * (dev->ev_next - i));
1110                 }
1111                 break;
1112         default:
1113                 BUG ();
1114         }
1115         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1116         event = &dev->event [dev->ev_next++];
1117         BUG_ON (dev->ev_next > N_EVENT);
1118         memset (event, 0, sizeof *event);
1119         event->type = type;
1120         return event;
1121 }
1122
1123 static ssize_t
1124 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1125 {
1126         struct dev_data         *dev = fd->private_data;
1127         ssize_t                 retval = -ESRCH;
1128
1129         /* report fd mode change before acting on it */
1130         if (dev->setup_abort) {
1131                 dev->setup_abort = 0;
1132                 retval = -EIDRM;
1133
1134         /* data and/or status stage for control request */
1135         } else if (dev->state == STATE_DEV_SETUP) {
1136
1137                 len = min_t(size_t, len, dev->setup_wLength);
1138                 if (dev->setup_in) {
1139                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1140                         if (retval == 0) {
1141                                 dev->state = STATE_DEV_CONNECTED;
1142                                 ++dev->udc_usage;
1143                                 spin_unlock_irq (&dev->lock);
1144                                 if (copy_from_user (dev->req->buf, buf, len))
1145                                         retval = -EFAULT;
1146                                 else {
1147                                         if (len < dev->setup_wLength)
1148                                                 dev->req->zero = 1;
1149                                         retval = usb_ep_queue (
1150                                                 dev->gadget->ep0, dev->req,
1151                                                 GFP_KERNEL);
1152                                 }
1153                                 spin_lock_irq(&dev->lock);
1154                                 --dev->udc_usage;
1155                                 if (retval < 0) {
1156                                         clean_req (dev->gadget->ep0, dev->req);
1157                                 } else
1158                                         retval = len;
1159
1160                                 return retval;
1161                         }
1162
1163                 /* can stall some OUT transfers */
1164                 } else if (dev->setup_can_stall) {
1165                         VDEBUG(dev, "ep0out stall\n");
1166                         (void) usb_ep_set_halt (dev->gadget->ep0);
1167                         retval = -EL2HLT;
1168                         dev->state = STATE_DEV_CONNECTED;
1169                 } else {
1170                         DBG(dev, "bogus ep0out stall!\n");
1171                 }
1172         } else
1173                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1174
1175         return retval;
1176 }
1177
1178 static int
1179 ep0_fasync (int f, struct file *fd, int on)
1180 {
1181         struct dev_data         *dev = fd->private_data;
1182         // caller must F_SETOWN before signal delivery happens
1183         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1184         return fasync_helper (f, fd, on, &dev->fasync);
1185 }
1186
1187 static struct usb_gadget_driver gadgetfs_driver;
1188
1189 static int
1190 dev_release (struct inode *inode, struct file *fd)
1191 {
1192         struct dev_data         *dev = fd->private_data;
1193
1194         /* closing ep0 === shutdown all */
1195
1196         if (dev->gadget_registered) {
1197                 usb_gadget_unregister_driver (&gadgetfs_driver);
1198                 dev->gadget_registered = false;
1199         }
1200
1201         /* at this point "good" hardware has disconnected the
1202          * device from USB; the host won't see it any more.
1203          * alternatively, all host requests will time out.
1204          */
1205
1206         kfree (dev->buf);
1207         dev->buf = NULL;
1208
1209         /* other endpoints were all decoupled from this device */
1210         spin_lock_irq(&dev->lock);
1211         dev->state = STATE_DEV_DISABLED;
1212         spin_unlock_irq(&dev->lock);
1213
1214         put_dev (dev);
1215         return 0;
1216 }
1217
1218 static unsigned int
1219 ep0_poll (struct file *fd, poll_table *wait)
1220 {
1221        struct dev_data         *dev = fd->private_data;
1222        int                     mask = 0;
1223
1224         if (dev->state <= STATE_DEV_OPENED)
1225                 return DEFAULT_POLLMASK;
1226
1227        poll_wait(fd, &dev->wait, wait);
1228
1229        spin_lock_irq (&dev->lock);
1230
1231        /* report fd mode change before acting on it */
1232        if (dev->setup_abort) {
1233                dev->setup_abort = 0;
1234                mask = POLLHUP;
1235                goto out;
1236        }
1237
1238        if (dev->state == STATE_DEV_SETUP) {
1239                if (dev->setup_in || dev->setup_can_stall)
1240                        mask = POLLOUT;
1241        } else {
1242                if (dev->ev_next != 0)
1243                        mask = POLLIN;
1244        }
1245 out:
1246        spin_unlock_irq(&dev->lock);
1247        return mask;
1248 }
1249
1250 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1251 {
1252         struct dev_data         *dev = fd->private_data;
1253         struct usb_gadget       *gadget = dev->gadget;
1254         long ret = -ENOTTY;
1255
1256         spin_lock_irq(&dev->lock);
1257         if (dev->state == STATE_DEV_OPENED ||
1258                         dev->state == STATE_DEV_UNBOUND) {
1259                 /* Not bound to a UDC */
1260         } else if (gadget->ops->ioctl) {
1261                 ++dev->udc_usage;
1262                 spin_unlock_irq(&dev->lock);
1263
1264                 ret = gadget->ops->ioctl (gadget, code, value);
1265
1266                 spin_lock_irq(&dev->lock);
1267                 --dev->udc_usage;
1268         }
1269         spin_unlock_irq(&dev->lock);
1270
1271         return ret;
1272 }
1273
1274 /*----------------------------------------------------------------------*/
1275
1276 /* The in-kernel gadget driver handles most ep0 issues, in particular
1277  * enumerating the single configuration (as provided from user space).
1278  *
1279  * Unrecognized ep0 requests may be handled in user space.
1280  */
1281
1282 static void make_qualifier (struct dev_data *dev)
1283 {
1284         struct usb_qualifier_descriptor         qual;
1285         struct usb_device_descriptor            *desc;
1286
1287         qual.bLength = sizeof qual;
1288         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1289         qual.bcdUSB = cpu_to_le16 (0x0200);
1290
1291         desc = dev->dev;
1292         qual.bDeviceClass = desc->bDeviceClass;
1293         qual.bDeviceSubClass = desc->bDeviceSubClass;
1294         qual.bDeviceProtocol = desc->bDeviceProtocol;
1295
1296         /* assumes ep0 uses the same value for both speeds ... */
1297         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1298
1299         qual.bNumConfigurations = 1;
1300         qual.bRESERVED = 0;
1301
1302         memcpy (dev->rbuf, &qual, sizeof qual);
1303 }
1304
1305 static int
1306 config_buf (struct dev_data *dev, u8 type, unsigned index)
1307 {
1308         int             len;
1309         int             hs = 0;
1310
1311         /* only one configuration */
1312         if (index > 0)
1313                 return -EINVAL;
1314
1315         if (gadget_is_dualspeed(dev->gadget)) {
1316                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1317                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1318                         hs = !hs;
1319         }
1320         if (hs) {
1321                 dev->req->buf = dev->hs_config;
1322                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1323         } else {
1324                 dev->req->buf = dev->config;
1325                 len = le16_to_cpu(dev->config->wTotalLength);
1326         }
1327         ((u8 *)dev->req->buf) [1] = type;
1328         return len;
1329 }
1330
1331 static int
1332 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1333 {
1334         struct dev_data                 *dev = get_gadget_data (gadget);
1335         struct usb_request              *req = dev->req;
1336         int                             value = -EOPNOTSUPP;
1337         struct usb_gadgetfs_event       *event;
1338         u16                             w_value = le16_to_cpu(ctrl->wValue);
1339         u16                             w_length = le16_to_cpu(ctrl->wLength);
1340
1341         if (w_length > RBUF_SIZE) {
1342                 if (ctrl->bRequestType & USB_DIR_IN) {
1343                         /* Cast away the const, we are going to overwrite on purpose. */
1344                         __le16 *temp = (__le16 *)&ctrl->wLength;
1345
1346                         *temp = cpu_to_le16(RBUF_SIZE);
1347                         w_length = RBUF_SIZE;
1348                 } else {
1349                         return value;
1350                 }
1351         }
1352
1353         spin_lock (&dev->lock);
1354         dev->setup_abort = 0;
1355         if (dev->state == STATE_DEV_UNCONNECTED) {
1356                 if (gadget_is_dualspeed(gadget)
1357                                 && gadget->speed == USB_SPEED_HIGH
1358                                 && dev->hs_config == NULL) {
1359                         spin_unlock(&dev->lock);
1360                         ERROR (dev, "no high speed config??\n");
1361                         return -EINVAL;
1362                 }
1363
1364                 dev->state = STATE_DEV_CONNECTED;
1365
1366                 INFO (dev, "connected\n");
1367                 event = next_event (dev, GADGETFS_CONNECT);
1368                 event->u.speed = gadget->speed;
1369                 ep0_readable (dev);
1370
1371         /* host may have given up waiting for response.  we can miss control
1372          * requests handled lower down (device/endpoint status and features);
1373          * then ep0_{read,write} will report the wrong status. controller
1374          * driver will have aborted pending i/o.
1375          */
1376         } else if (dev->state == STATE_DEV_SETUP)
1377                 dev->setup_abort = 1;
1378
1379         req->buf = dev->rbuf;
1380         req->context = NULL;
1381         switch (ctrl->bRequest) {
1382
1383         case USB_REQ_GET_DESCRIPTOR:
1384                 if (ctrl->bRequestType != USB_DIR_IN)
1385                         goto unrecognized;
1386                 switch (w_value >> 8) {
1387
1388                 case USB_DT_DEVICE:
1389                         value = min (w_length, (u16) sizeof *dev->dev);
1390                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1391                         req->buf = dev->dev;
1392                         break;
1393                 case USB_DT_DEVICE_QUALIFIER:
1394                         if (!dev->hs_config)
1395                                 break;
1396                         value = min (w_length, (u16)
1397                                 sizeof (struct usb_qualifier_descriptor));
1398                         make_qualifier (dev);
1399                         break;
1400                 case USB_DT_OTHER_SPEED_CONFIG:
1401                         // FALLTHROUGH
1402                 case USB_DT_CONFIG:
1403                         value = config_buf (dev,
1404                                         w_value >> 8,
1405                                         w_value & 0xff);
1406                         if (value >= 0)
1407                                 value = min (w_length, (u16) value);
1408                         break;
1409                 case USB_DT_STRING:
1410                         goto unrecognized;
1411
1412                 default:                // all others are errors
1413                         break;
1414                 }
1415                 break;
1416
1417         /* currently one config, two speeds */
1418         case USB_REQ_SET_CONFIGURATION:
1419                 if (ctrl->bRequestType != 0)
1420                         goto unrecognized;
1421                 if (0 == (u8) w_value) {
1422                         value = 0;
1423                         dev->current_config = 0;
1424                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1425                         // user mode expected to disable endpoints
1426                 } else {
1427                         u8      config, power;
1428
1429                         if (gadget_is_dualspeed(gadget)
1430                                         && gadget->speed == USB_SPEED_HIGH) {
1431                                 config = dev->hs_config->bConfigurationValue;
1432                                 power = dev->hs_config->bMaxPower;
1433                         } else {
1434                                 config = dev->config->bConfigurationValue;
1435                                 power = dev->config->bMaxPower;
1436                         }
1437
1438                         if (config == (u8) w_value) {
1439                                 value = 0;
1440                                 dev->current_config = config;
1441                                 usb_gadget_vbus_draw(gadget, 2 * power);
1442                         }
1443                 }
1444
1445                 /* report SET_CONFIGURATION like any other control request,
1446                  * except that usermode may not stall this.  the next
1447                  * request mustn't be allowed start until this finishes:
1448                  * endpoints and threads set up, etc.
1449                  *
1450                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1451                  * has bad/racey automagic that prevents synchronizing here.
1452                  * even kernel mode drivers often miss them.
1453                  */
1454                 if (value == 0) {
1455                         INFO (dev, "configuration #%d\n", dev->current_config);
1456                         usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1457                         if (dev->usermode_setup) {
1458                                 dev->setup_can_stall = 0;
1459                                 goto delegate;
1460                         }
1461                 }
1462                 break;
1463
1464 #ifndef CONFIG_USB_PXA25X
1465         /* PXA automagically handles this request too */
1466         case USB_REQ_GET_CONFIGURATION:
1467                 if (ctrl->bRequestType != 0x80)
1468                         goto unrecognized;
1469                 *(u8 *)req->buf = dev->current_config;
1470                 value = min (w_length, (u16) 1);
1471                 break;
1472 #endif
1473
1474         default:
1475 unrecognized:
1476                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1477                         dev->usermode_setup ? "delegate" : "fail",
1478                         ctrl->bRequestType, ctrl->bRequest,
1479                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1480
1481                 /* if there's an ep0 reader, don't stall */
1482                 if (dev->usermode_setup) {
1483                         dev->setup_can_stall = 1;
1484 delegate:
1485                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1486                                                 ? 1 : 0;
1487                         dev->setup_wLength = w_length;
1488                         dev->setup_out_ready = 0;
1489                         dev->setup_out_error = 0;
1490                         value = 0;
1491
1492                         /* read DATA stage for OUT right away */
1493                         if (unlikely (!dev->setup_in && w_length)) {
1494                                 value = setup_req (gadget->ep0, dev->req,
1495                                                         w_length);
1496                                 if (value < 0)
1497                                         break;
1498
1499                                 ++dev->udc_usage;
1500                                 spin_unlock (&dev->lock);
1501                                 value = usb_ep_queue (gadget->ep0, dev->req,
1502                                                         GFP_KERNEL);
1503                                 spin_lock (&dev->lock);
1504                                 --dev->udc_usage;
1505                                 if (value < 0) {
1506                                         clean_req (gadget->ep0, dev->req);
1507                                         break;
1508                                 }
1509
1510                                 /* we can't currently stall these */
1511                                 dev->setup_can_stall = 0;
1512                         }
1513
1514                         /* state changes when reader collects event */
1515                         event = next_event (dev, GADGETFS_SETUP);
1516                         event->u.setup = *ctrl;
1517                         ep0_readable (dev);
1518                         spin_unlock (&dev->lock);
1519                         return 0;
1520                 }
1521         }
1522
1523         /* proceed with data transfer and status phases? */
1524         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1525                 req->length = value;
1526                 req->zero = value < w_length;
1527
1528                 ++dev->udc_usage;
1529                 spin_unlock (&dev->lock);
1530                 value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1531                 spin_lock(&dev->lock);
1532                 --dev->udc_usage;
1533                 spin_unlock(&dev->lock);
1534                 if (value < 0) {
1535                         DBG (dev, "ep_queue --> %d\n", value);
1536                         req->status = 0;
1537                 }
1538                 return value;
1539         }
1540
1541         /* device stalls when value < 0 */
1542         spin_unlock (&dev->lock);
1543         return value;
1544 }
1545
1546 static void destroy_ep_files (struct dev_data *dev)
1547 {
1548         DBG (dev, "%s %d\n", __func__, dev->state);
1549
1550         /* dev->state must prevent interference */
1551         spin_lock_irq (&dev->lock);
1552         while (!list_empty(&dev->epfiles)) {
1553                 struct ep_data  *ep;
1554                 struct inode    *parent;
1555                 struct dentry   *dentry;
1556
1557                 /* break link to FS */
1558                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1559                 list_del_init (&ep->epfiles);
1560                 spin_unlock_irq (&dev->lock);
1561
1562                 dentry = ep->dentry;
1563                 ep->dentry = NULL;
1564                 parent = d_inode(dentry->d_parent);
1565
1566                 /* break link to controller */
1567                 mutex_lock(&ep->lock);
1568                 if (ep->state == STATE_EP_ENABLED)
1569                         (void) usb_ep_disable (ep->ep);
1570                 ep->state = STATE_EP_UNBOUND;
1571                 usb_ep_free_request (ep->ep, ep->req);
1572                 ep->ep = NULL;
1573                 mutex_unlock(&ep->lock);
1574
1575                 wake_up (&ep->wait);
1576                 put_ep (ep);
1577
1578                 /* break link to dcache */
1579                 inode_lock(parent);
1580                 d_delete (dentry);
1581                 dput (dentry);
1582                 inode_unlock(parent);
1583
1584                 spin_lock_irq (&dev->lock);
1585         }
1586         spin_unlock_irq (&dev->lock);
1587 }
1588
1589
1590 static struct dentry *
1591 gadgetfs_create_file (struct super_block *sb, char const *name,
1592                 void *data, const struct file_operations *fops);
1593
1594 static int activate_ep_files (struct dev_data *dev)
1595 {
1596         struct usb_ep   *ep;
1597         struct ep_data  *data;
1598
1599         gadget_for_each_ep (ep, dev->gadget) {
1600
1601                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1602                 if (!data)
1603                         goto enomem0;
1604                 data->state = STATE_EP_DISABLED;
1605                 mutex_init(&data->lock);
1606                 init_waitqueue_head (&data->wait);
1607
1608                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1609                 refcount_set (&data->count, 1);
1610                 data->dev = dev;
1611                 get_dev (dev);
1612
1613                 data->ep = ep;
1614                 ep->driver_data = data;
1615
1616                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1617                 if (!data->req)
1618                         goto enomem1;
1619
1620                 data->dentry = gadgetfs_create_file (dev->sb, data->name,
1621                                 data, &ep_io_operations);
1622                 if (!data->dentry)
1623                         goto enomem2;
1624                 list_add_tail (&data->epfiles, &dev->epfiles);
1625         }
1626         return 0;
1627
1628 enomem2:
1629         usb_ep_free_request (ep, data->req);
1630 enomem1:
1631         put_dev (dev);
1632         kfree (data);
1633 enomem0:
1634         DBG (dev, "%s enomem\n", __func__);
1635         destroy_ep_files (dev);
1636         return -ENOMEM;
1637 }
1638
1639 static void
1640 gadgetfs_unbind (struct usb_gadget *gadget)
1641 {
1642         struct dev_data         *dev = get_gadget_data (gadget);
1643
1644         DBG (dev, "%s\n", __func__);
1645
1646         spin_lock_irq (&dev->lock);
1647         dev->state = STATE_DEV_UNBOUND;
1648         while (dev->udc_usage > 0) {
1649                 spin_unlock_irq(&dev->lock);
1650                 usleep_range(1000, 2000);
1651                 spin_lock_irq(&dev->lock);
1652         }
1653         spin_unlock_irq (&dev->lock);
1654
1655         destroy_ep_files (dev);
1656         gadget->ep0->driver_data = NULL;
1657         set_gadget_data (gadget, NULL);
1658
1659         /* we've already been disconnected ... no i/o is active */
1660         if (dev->req)
1661                 usb_ep_free_request (gadget->ep0, dev->req);
1662         DBG (dev, "%s done\n", __func__);
1663         put_dev (dev);
1664 }
1665
1666 static struct dev_data          *the_device;
1667
1668 static int gadgetfs_bind(struct usb_gadget *gadget,
1669                 struct usb_gadget_driver *driver)
1670 {
1671         struct dev_data         *dev = the_device;
1672
1673         if (!dev)
1674                 return -ESRCH;
1675         if (0 != strcmp (CHIP, gadget->name)) {
1676                 pr_err("%s expected %s controller not %s\n",
1677                         shortname, CHIP, gadget->name);
1678                 return -ENODEV;
1679         }
1680
1681         set_gadget_data (gadget, dev);
1682         dev->gadget = gadget;
1683         gadget->ep0->driver_data = dev;
1684
1685         /* preallocate control response and buffer */
1686         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1687         if (!dev->req)
1688                 goto enomem;
1689         dev->req->context = NULL;
1690         dev->req->complete = epio_complete;
1691
1692         if (activate_ep_files (dev) < 0)
1693                 goto enomem;
1694
1695         INFO (dev, "bound to %s driver\n", gadget->name);
1696         spin_lock_irq(&dev->lock);
1697         dev->state = STATE_DEV_UNCONNECTED;
1698         spin_unlock_irq(&dev->lock);
1699         get_dev (dev);
1700         return 0;
1701
1702 enomem:
1703         gadgetfs_unbind (gadget);
1704         return -ENOMEM;
1705 }
1706
1707 static void
1708 gadgetfs_disconnect (struct usb_gadget *gadget)
1709 {
1710         struct dev_data         *dev = get_gadget_data (gadget);
1711         unsigned long           flags;
1712
1713         spin_lock_irqsave (&dev->lock, flags);
1714         if (dev->state == STATE_DEV_UNCONNECTED)
1715                 goto exit;
1716         dev->state = STATE_DEV_UNCONNECTED;
1717
1718         INFO (dev, "disconnected\n");
1719         next_event (dev, GADGETFS_DISCONNECT);
1720         ep0_readable (dev);
1721 exit:
1722         spin_unlock_irqrestore (&dev->lock, flags);
1723 }
1724
1725 static void
1726 gadgetfs_suspend (struct usb_gadget *gadget)
1727 {
1728         struct dev_data         *dev = get_gadget_data (gadget);
1729         unsigned long           flags;
1730
1731         INFO (dev, "suspended from state %d\n", dev->state);
1732         spin_lock_irqsave(&dev->lock, flags);
1733         switch (dev->state) {
1734         case STATE_DEV_SETUP:           // VERY odd... host died??
1735         case STATE_DEV_CONNECTED:
1736         case STATE_DEV_UNCONNECTED:
1737                 next_event (dev, GADGETFS_SUSPEND);
1738                 ep0_readable (dev);
1739                 /* FALLTHROUGH */
1740         default:
1741                 break;
1742         }
1743         spin_unlock_irqrestore(&dev->lock, flags);
1744 }
1745
1746 static struct usb_gadget_driver gadgetfs_driver = {
1747         .function       = (char *) driver_desc,
1748         .bind           = gadgetfs_bind,
1749         .unbind         = gadgetfs_unbind,
1750         .setup          = gadgetfs_setup,
1751         .reset          = gadgetfs_disconnect,
1752         .disconnect     = gadgetfs_disconnect,
1753         .suspend        = gadgetfs_suspend,
1754
1755         .driver = {
1756                 .name           = (char *) shortname,
1757         },
1758 };
1759
1760 /*----------------------------------------------------------------------*/
1761 /* DEVICE INITIALIZATION
1762  *
1763  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1764  *     status = write (fd, descriptors, sizeof descriptors)
1765  *
1766  * That write establishes the device configuration, so the kernel can
1767  * bind to the controller ... guaranteeing it can handle enumeration
1768  * at all necessary speeds.  Descriptor order is:
1769  *
1770  * . message tag (u32, host order) ... for now, must be zero; it
1771  *      would change to support features like multi-config devices
1772  * . full/low speed config ... all wTotalLength bytes (with interface,
1773  *      class, altsetting, endpoint, and other descriptors)
1774  * . high speed config ... all descriptors, for high speed operation;
1775  *      this one's optional except for high-speed hardware
1776  * . device descriptor
1777  *
1778  * Endpoints are not yet enabled. Drivers must wait until device
1779  * configuration and interface altsetting changes create
1780  * the need to configure (or unconfigure) them.
1781  *
1782  * After initialization, the device stays active for as long as that
1783  * $CHIP file is open.  Events must then be read from that descriptor,
1784  * such as configuration notifications.
1785  */
1786
1787 static int is_valid_config(struct usb_config_descriptor *config,
1788                 unsigned int total)
1789 {
1790         return config->bDescriptorType == USB_DT_CONFIG
1791                 && config->bLength == USB_DT_CONFIG_SIZE
1792                 && total >= USB_DT_CONFIG_SIZE
1793                 && config->bConfigurationValue != 0
1794                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1795                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1796         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1797         /* FIXME check lengths: walk to end */
1798 }
1799
1800 static ssize_t
1801 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1802 {
1803         struct dev_data         *dev = fd->private_data;
1804         ssize_t                 value, length = len;
1805         unsigned                total;
1806         u32                     tag;
1807         char                    *kbuf;
1808
1809         spin_lock_irq(&dev->lock);
1810         if (dev->state > STATE_DEV_OPENED) {
1811                 value = ep0_write(fd, buf, len, ptr);
1812                 spin_unlock_irq(&dev->lock);
1813                 return value;
1814         }
1815         spin_unlock_irq(&dev->lock);
1816
1817         if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1818             (len > PAGE_SIZE * 4))
1819                 return -EINVAL;
1820
1821         /* we might need to change message format someday */
1822         if (copy_from_user (&tag, buf, 4))
1823                 return -EFAULT;
1824         if (tag != 0)
1825                 return -EINVAL;
1826         buf += 4;
1827         length -= 4;
1828
1829         kbuf = memdup_user(buf, length);
1830         if (IS_ERR(kbuf))
1831                 return PTR_ERR(kbuf);
1832
1833         spin_lock_irq (&dev->lock);
1834         value = -EINVAL;
1835         if (dev->buf) {
1836                 spin_unlock_irq(&dev->lock);
1837                 kfree(kbuf);
1838                 return value;
1839         }
1840         dev->buf = kbuf;
1841
1842         /* full or low speed config */
1843         dev->config = (void *) kbuf;
1844         total = le16_to_cpu(dev->config->wTotalLength);
1845         if (!is_valid_config(dev->config, total) ||
1846                         total > length - USB_DT_DEVICE_SIZE)
1847                 goto fail;
1848         kbuf += total;
1849         length -= total;
1850
1851         /* optional high speed config */
1852         if (kbuf [1] == USB_DT_CONFIG) {
1853                 dev->hs_config = (void *) kbuf;
1854                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1855                 if (!is_valid_config(dev->hs_config, total) ||
1856                                 total > length - USB_DT_DEVICE_SIZE)
1857                         goto fail;
1858                 kbuf += total;
1859                 length -= total;
1860         } else {
1861                 dev->hs_config = NULL;
1862         }
1863
1864         /* could support multiple configs, using another encoding! */
1865
1866         /* device descriptor (tweaked for paranoia) */
1867         if (length != USB_DT_DEVICE_SIZE)
1868                 goto fail;
1869         dev->dev = (void *)kbuf;
1870         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1871                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1872                         || dev->dev->bNumConfigurations != 1)
1873                 goto fail;
1874         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1875
1876         /* triggers gadgetfs_bind(); then we can enumerate. */
1877         spin_unlock_irq (&dev->lock);
1878         if (dev->hs_config)
1879                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1880         else
1881                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1882
1883         value = usb_gadget_probe_driver(&gadgetfs_driver);
1884         if (value != 0) {
1885                 spin_lock_irq(&dev->lock);
1886                 goto fail;
1887         } else {
1888                 /* at this point "good" hardware has for the first time
1889                  * let the USB the host see us.  alternatively, if users
1890                  * unplug/replug that will clear all the error state.
1891                  *
1892                  * note:  everything running before here was guaranteed
1893                  * to choke driver model style diagnostics.  from here
1894                  * on, they can work ... except in cleanup paths that
1895                  * kick in after the ep0 descriptor is closed.
1896                  */
1897                 value = len;
1898                 dev->gadget_registered = true;
1899         }
1900         return value;
1901
1902 fail:
1903         dev->config = NULL;
1904         dev->hs_config = NULL;
1905         dev->dev = NULL;
1906         spin_unlock_irq (&dev->lock);
1907         pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev);
1908         kfree (dev->buf);
1909         dev->buf = NULL;
1910         return value;
1911 }
1912
1913 static int
1914 dev_open (struct inode *inode, struct file *fd)
1915 {
1916         struct dev_data         *dev = inode->i_private;
1917         int                     value = -EBUSY;
1918
1919         spin_lock_irq(&dev->lock);
1920         if (dev->state == STATE_DEV_DISABLED) {
1921                 dev->ev_next = 0;
1922                 dev->state = STATE_DEV_OPENED;
1923                 fd->private_data = dev;
1924                 get_dev (dev);
1925                 value = 0;
1926         }
1927         spin_unlock_irq(&dev->lock);
1928         return value;
1929 }
1930
1931 static const struct file_operations ep0_operations = {
1932         .llseek =       no_llseek,
1933
1934         .open =         dev_open,
1935         .read =         ep0_read,
1936         .write =        dev_config,
1937         .fasync =       ep0_fasync,
1938         .poll =         ep0_poll,
1939         .unlocked_ioctl = dev_ioctl,
1940         .release =      dev_release,
1941 };
1942
1943 /*----------------------------------------------------------------------*/
1944
1945 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1946  *
1947  * Mounting the filesystem creates a controller file, used first for
1948  * device configuration then later for event monitoring.
1949  */
1950
1951
1952 /* FIXME PAM etc could set this security policy without mount options
1953  * if epfiles inherited ownership and permissons from ep0 ...
1954  */
1955
1956 static unsigned default_uid;
1957 static unsigned default_gid;
1958 static unsigned default_perm = S_IRUSR | S_IWUSR;
1959
1960 module_param (default_uid, uint, 0644);
1961 module_param (default_gid, uint, 0644);
1962 module_param (default_perm, uint, 0644);
1963
1964
1965 static struct inode *
1966 gadgetfs_make_inode (struct super_block *sb,
1967                 void *data, const struct file_operations *fops,
1968                 int mode)
1969 {
1970         struct inode *inode = new_inode (sb);
1971
1972         if (inode) {
1973                 inode->i_ino = get_next_ino();
1974                 inode->i_mode = mode;
1975                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
1976                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
1977                 inode->i_atime = inode->i_mtime = inode->i_ctime
1978                                 = current_time(inode);
1979                 inode->i_private = data;
1980                 inode->i_fop = fops;
1981         }
1982         return inode;
1983 }
1984
1985 /* creates in fs root directory, so non-renamable and non-linkable.
1986  * so inode and dentry are paired, until device reconfig.
1987  */
1988 static struct dentry *
1989 gadgetfs_create_file (struct super_block *sb, char const *name,
1990                 void *data, const struct file_operations *fops)
1991 {
1992         struct dentry   *dentry;
1993         struct inode    *inode;
1994
1995         dentry = d_alloc_name(sb->s_root, name);
1996         if (!dentry)
1997                 return NULL;
1998
1999         inode = gadgetfs_make_inode (sb, data, fops,
2000                         S_IFREG | (default_perm & S_IRWXUGO));
2001         if (!inode) {
2002                 dput(dentry);
2003                 return NULL;
2004         }
2005         d_add (dentry, inode);
2006         return dentry;
2007 }
2008
2009 static const struct super_operations gadget_fs_operations = {
2010         .statfs =       simple_statfs,
2011         .drop_inode =   generic_delete_inode,
2012 };
2013
2014 static int
2015 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
2016 {
2017         struct inode    *inode;
2018         struct dev_data *dev;
2019
2020         if (the_device)
2021                 return -ESRCH;
2022
2023         CHIP = usb_get_gadget_udc_name();
2024         if (!CHIP)
2025                 return -ENODEV;
2026
2027         /* superblock */
2028         sb->s_blocksize = PAGE_SIZE;
2029         sb->s_blocksize_bits = PAGE_SHIFT;
2030         sb->s_magic = GADGETFS_MAGIC;
2031         sb->s_op = &gadget_fs_operations;
2032         sb->s_time_gran = 1;
2033
2034         /* root inode */
2035         inode = gadgetfs_make_inode (sb,
2036                         NULL, &simple_dir_operations,
2037                         S_IFDIR | S_IRUGO | S_IXUGO);
2038         if (!inode)
2039                 goto Enomem;
2040         inode->i_op = &simple_dir_inode_operations;
2041         if (!(sb->s_root = d_make_root (inode)))
2042                 goto Enomem;
2043
2044         /* the ep0 file is named after the controller we expect;
2045          * user mode code can use it for sanity checks, like we do.
2046          */
2047         dev = dev_new ();
2048         if (!dev)
2049                 goto Enomem;
2050
2051         dev->sb = sb;
2052         dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2053         if (!dev->dentry) {
2054                 put_dev(dev);
2055                 goto Enomem;
2056         }
2057
2058         /* other endpoint files are available after hardware setup,
2059          * from binding to a controller.
2060          */
2061         the_device = dev;
2062         return 0;
2063
2064 Enomem:
2065         kfree(CHIP);
2066         CHIP = NULL;
2067
2068         return -ENOMEM;
2069 }
2070
2071 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2072 static struct dentry *
2073 gadgetfs_mount (struct file_system_type *t, int flags,
2074                 const char *path, void *opts)
2075 {
2076         return mount_single (t, flags, opts, gadgetfs_fill_super);
2077 }
2078
2079 static void
2080 gadgetfs_kill_sb (struct super_block *sb)
2081 {
2082         kill_litter_super (sb);
2083         if (the_device) {
2084                 put_dev (the_device);
2085                 the_device = NULL;
2086         }
2087         kfree(CHIP);
2088         CHIP = NULL;
2089 }
2090
2091 /*----------------------------------------------------------------------*/
2092
2093 static struct file_system_type gadgetfs_type = {
2094         .owner          = THIS_MODULE,
2095         .name           = shortname,
2096         .mount          = gadgetfs_mount,
2097         .kill_sb        = gadgetfs_kill_sb,
2098 };
2099 MODULE_ALIAS_FS("gadgetfs");
2100
2101 /*----------------------------------------------------------------------*/
2102
2103 static int __init init (void)
2104 {
2105         int status;
2106
2107         status = register_filesystem (&gadgetfs_type);
2108         if (status == 0)
2109                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2110                         shortname, driver_desc);
2111         return status;
2112 }
2113 module_init (init);
2114
2115 static void __exit cleanup (void)
2116 {
2117         pr_debug ("unregister %s\n", shortname);
2118         unregister_filesystem (&gadgetfs_type);
2119 }
2120 module_exit (cleanup);
2121