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/fs_context.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/uts.h>
  18 #include <linux/wait.h>
  19 #include <linux/compiler.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23 #include <linux/poll.h>
  24 #include <linux/kthread.h>
  25 #include <linux/aio.h>
  26 #include <linux/uio.h>
  27 #include <linux/refcount.h>
  28 #include <linux/delay.h>
  29 #include <linux/device.h>
  30 #include <linux/moduleparam.h>
  31
  32 #include <linux/usb/gadgetfs.h>
  33 #include <linux/usb/gadget.h>
  34
  35
  36 /*
  37  * The gadgetfs API maps each endpoint to a file descriptor so that you
  38  * can use standard synchronous read/write calls for I/O.  There's some
  39  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  40  * drivers show how this works in practice.  You can also use AIO to
  41  * eliminate I/O gaps between requests, to help when streaming data.
  42  *
  43  * Key parts that must be USB-specific are protocols defining how the
  44  * read/write operations relate to the hardware state machines.  There
  45  * are two types of files.  One type is for the device, implementing ep0.
  46  * The other type is for each IN or OUT endpoint.  In both cases, the
  47  * user mode driver must configure the hardware before using it.
  48  *
  49  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  50  *   (by writing configuration and device descriptors).  Afterwards it
  51  *   may serve as a source of device events, used to handle all control
  52  *   requests other than basic enumeration.
  53  *
  54  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  55  *   called when each /dev/gadget/ep* file is configured (by writing
  56  *   endpoint descriptors).  Afterwards these files are used to write()
  57  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  58  *   direction" request is issued (like reading an IN endpoint).
  59  *
  60  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  61  * not possible on all hardware.  For example, precise fault handling with
  62  * respect to data left in endpoint fifos after aborted operations; or
  63  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  64  */
  65
  66 #define DRIVER_DESC     "USB Gadget filesystem"
  67 #define DRIVER_VERSION  "24 Aug 2004"
  68
  69 static const char driver_desc [] = DRIVER_DESC;
  70 static const char shortname [] = "gadgetfs";
  71
  72 MODULE_DESCRIPTION (DRIVER_DESC);
  73 MODULE_AUTHOR ("David Brownell");
  74 MODULE_LICENSE ("GPL");
  75
  76 static int ep_open(struct inode *, struct file *);
  77
  78
  79 /*----------------------------------------------------------------------*/
  80
  81 #define GADGETFS_MAGIC          0xaee71ee7
  82
  83 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  84 enum ep0_state {
  85         /* DISABLED is the initial state. */
  86         STATE_DEV_DISABLED = 0,
  87
  88         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  89          * ep0/device i/o modes and binding to the controller.  Driver
  90          * must always write descriptors to initialize the device, then
  91          * the device becomes UNCONNECTED until enumeration.
  92          */
  93         STATE_DEV_OPENED,
  94
  95         /* From then on, ep0 fd is in either of two basic modes:
  96          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
  97          * - SETUP: read/write will transfer control data and succeed;
  98          *   or if "wrong direction", performs protocol stall
  99          */
 100         STATE_DEV_UNCONNECTED,
 101         STATE_DEV_CONNECTED,
 102         STATE_DEV_SETUP,
 103
 104         /* UNBOUND means the driver closed ep0, so the device won't be
 105          * accessible again (DEV_DISABLED) until all fds are closed.
 106          */
 107         STATE_DEV_UNBOUND,
 108 };
 109
 110 /* enough for the whole queue: most events invalidate others */
 111 #define N_EVENT                 5
 112
 113 #define RBUF_SIZE               256
 114
 115 struct dev_data {
 116         spinlock_t                      lock;
 117         refcount_t                      count;
 118         int                             udc_usage;
 119         enum ep0_state                  state;          /* P: lock */
 120         struct usb_gadgetfs_event       event [N_EVENT];
 121         unsigned                        ev_next;
 122         struct fasync_struct            *fasync;
 123         u8                              current_config;
 124
 125         /* drivers reading ep0 MUST handle control requests (SETUP)
 126          * reported that way; else the host will time out.
 127          */
 128         unsigned                        usermode_setup : 1,
 129                                         setup_in : 1,
 130                                         setup_can_stall : 1,
 131                                         setup_out_ready : 1,
 132                                         setup_out_error : 1,
 133                                         setup_abort : 1,
 134                                         gadget_registered : 1;
 135         unsigned                        setup_wLength;
 136
 137         /* the rest is basically write-once */
 138         struct usb_config_descriptor    *config, *hs_config;
 139         struct usb_device_descriptor    *dev;
 140         struct usb_request              *req;
 141         struct usb_gadget               *gadget;
 142         struct list_head                epfiles;
 143         void                            *buf;
 144         wait_queue_head_t               wait;
 145         struct super_block              *sb;
 146         struct dentry                   *dentry;
 147
 148         /* except this scratch i/o buffer for ep0 */
 149         u8                              rbuf[RBUF_SIZE];
 150 };
 151
 152 static inline void get_dev (struct dev_data *data)
 153 {
 154         refcount_inc (&data->count);
 155 }
 156
 157 static void put_dev (struct dev_data *data)
 158 {
 159         if (likely (!refcount_dec_and_test (&data->count)))
 160                 return;
 161         /* needs no more cleanup */
 162         BUG_ON (waitqueue_active (&data->wait));
 163         kfree (data);
 164 }
 165
 166 static struct dev_data *dev_new (void)
 167 {
 168         struct dev_data         *dev;
 169
 170         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 171         if (!dev)
 172                 return NULL;
 173         dev->state = STATE_DEV_DISABLED;
 174         refcount_set (&dev->count, 1);
 175         spin_lock_init (&dev->lock);
 176         INIT_LIST_HEAD (&dev->epfiles);
 177         init_waitqueue_head (&dev->wait);
 178         return dev;
 179 }
 180
 181 /*----------------------------------------------------------------------*/
 182
 183 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 184 enum ep_state {
 185         STATE_EP_DISABLED = 0,
 186         STATE_EP_READY,
 187         STATE_EP_ENABLED,
 188         STATE_EP_UNBOUND,
 189 };
 190
 191 struct ep_data {
 192         struct mutex                    lock;
 193         enum ep_state                   state;
 194         refcount_t                      count;
 195         struct dev_data                 *dev;
 196         /* must hold dev->lock before accessing ep or req */
 197         struct usb_ep                   *ep;
 198         struct usb_request              *req;
 199         ssize_t                         status;
 200         char                            name [16];
 201         struct usb_endpoint_descriptor  desc, hs_desc;
 202         struct list_head                epfiles;
 203         wait_queue_head_t               wait;
 204         struct dentry                   *dentry;
 205 };
 206
 207 static inline void get_ep (struct ep_data *data)
 208 {
 209         refcount_inc (&data->count);
 210 }
 211
 212 static void put_ep (struct ep_data *data)
 213 {
 214         if (likely (!refcount_dec_and_test (&data->count)))
 215                 return;
 216         put_dev (data->dev);
 217         /* needs no more cleanup */
 218         BUG_ON (!list_empty (&data->epfiles));
 219         BUG_ON (waitqueue_active (&data->wait));
 220         kfree (data);
 221 }
 222
 223 /*----------------------------------------------------------------------*/
 224
 225 /* most "how to use the hardware" policy choices are in userspace:
 226  * mapping endpoint roles (which the driver needs) to the capabilities
 227  * which the usb controller has.  most of those capabilities are exposed
 228  * implicitly, starting with the driver name and then endpoint names.
 229  */
 230
 231 static const char *CHIP;
 232 static DEFINE_MUTEX(sb_mutex);          /* Serialize superblock operations */
 233
 234 /*----------------------------------------------------------------------*/
 235
 236 /* NOTE:  don't use dev_printk calls before binding to the gadget
 237  * at the end of ep0 configuration, or after unbind.
 238  */
 239
 240 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 241 #define xprintk(d,level,fmt,args...) \
 242         printk(level "%s: " fmt , shortname , ## args)
 243
 244 #ifdef DEBUG
 245 #define DBG(dev,fmt,args...) \
 246         xprintk(dev , KERN_DEBUG , fmt , ## args)
 247 #else
 248 #define DBG(dev,fmt,args...) \
 249         do { } while (0)
 250 #endif /* DEBUG */
 251
 252 #ifdef VERBOSE_DEBUG
 253 #define VDEBUG  DBG
 254 #else
 255 #define VDEBUG(dev,fmt,args...) \
 256         do { } while (0)
 257 #endif /* DEBUG */
 258
 259 #define ERROR(dev,fmt,args...) \
 260         xprintk(dev , KERN_ERR , fmt , ## args)
 261 #define INFO(dev,fmt,args...) \
 262         xprintk(dev , KERN_INFO , fmt , ## args)
 263
 264
 265 /*----------------------------------------------------------------------*/
 266
 267 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 268  *
 269  * After opening, configure non-control endpoints.  Then use normal
 270  * stream read() and write() requests; and maybe ioctl() to get more
 271  * precise FIFO status when recovering from cancellation.
 272  */
 273
 274 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 275 {
 276         struct ep_data  *epdata = ep->driver_data;
 277
 278         if (!req->context)
 279                 return;
 280         if (req->status)
 281                 epdata->status = req->status;
 282         else
 283                 epdata->status = req->actual;
 284         complete ((struct completion *)req->context);
 285 }
 286
 287 /* tasklock endpoint, returning when it's connected.
 288  * still need dev->lock to use epdata->ep.
 289  */
 290 static int
 291 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 292 {
 293         int     val;
 294
 295         if (f_flags & O_NONBLOCK) {
 296                 if (!mutex_trylock(&epdata->lock))
 297                         goto nonblock;
 298                 if (epdata->state != STATE_EP_ENABLED &&
 299                     (!is_write || epdata->state != STATE_EP_READY)) {
 300                         mutex_unlock(&epdata->lock);
 301 nonblock:
 302                         val = -EAGAIN;
 303                 } else
 304                         val = 0;
 305                 return val;
 306         }
 307
 308         val = mutex_lock_interruptible(&epdata->lock);
 309         if (val < 0)
 310                 return val;
 311
 312         switch (epdata->state) {
 313         case STATE_EP_ENABLED:
 314                 return 0;
 315         case STATE_EP_READY:                    /* not configured yet */
 316                 if (is_write)
 317                         return 0;
 318                 fallthrough;
 319         case STATE_EP_UNBOUND:                  /* clean disconnect */
 320                 break;
 321         // case STATE_EP_DISABLED:              /* "can't happen" */
 322         default:                                /* error! */
 323                 pr_debug ("%s: ep %p not available, state %d\n",
 324                                 shortname, epdata, epdata->state);
 325         }
 326         mutex_unlock(&epdata->lock);
 327         return -ENODEV;
 328 }
 329
 330 static ssize_t
 331 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 332 {
 333         DECLARE_COMPLETION_ONSTACK (done);
 334         int value;
 335
 336         spin_lock_irq (&epdata->dev->lock);
 337         if (likely (epdata->ep != NULL)) {
 338                 struct usb_request      *req = epdata->req;
 339
 340                 req->context = &done;
 341                 req->complete = epio_complete;
 342                 req->buf = buf;
 343                 req->length = len;
 344                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 345         } else
 346                 value = -ENODEV;
 347         spin_unlock_irq (&epdata->dev->lock);
 348
 349         if (likely (value == 0)) {
 350                 value = wait_for_completion_interruptible(&done);
 351                 if (value != 0) {
 352                         spin_lock_irq (&epdata->dev->lock);
 353                         if (likely (epdata->ep != NULL)) {
 354                                 DBG (epdata->dev, "%s i/o interrupted\n",
 355                                                 epdata->name);
 356                                 usb_ep_dequeue (epdata->ep, epdata->req);
 357                                 spin_unlock_irq (&epdata->dev->lock);
 358
 359                                 wait_for_completion(&done);
 360                                 if (epdata->status == -ECONNRESET)
 361                                         epdata->status = -EINTR;
 362                         } else {
 363                                 spin_unlock_irq (&epdata->dev->lock);
 364
 365                                 DBG (epdata->dev, "endpoint gone\n");
 366                                 wait_for_completion(&done);
 367                                 epdata->status = -ENODEV;
 368                         }
 369                 }
 370                 return epdata->status;
 371         }
 372         return value;
 373 }
 374
 375 static int
 376 ep_release (struct inode *inode, struct file *fd)
 377 {
 378         struct ep_data          *data = fd->private_data;
 379         int value;
 380
 381         value = mutex_lock_interruptible(&data->lock);
 382         if (value < 0)
 383                 return value;
 384
 385         /* clean up if this can be reopened */
 386         if (data->state != STATE_EP_UNBOUND) {
 387                 data->state = STATE_EP_DISABLED;
 388                 data->desc.bDescriptorType = 0;
 389                 data->hs_desc.bDescriptorType = 0;
 390                 usb_ep_disable(data->ep);
 391         }
 392         mutex_unlock(&data->lock);
 393         put_ep (data);
 394         return 0;
 395 }
 396
 397 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 398 {
 399         struct ep_data          *data = fd->private_data;
 400         int                     status;
 401
 402         if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
 403                 return status;
 404
 405         spin_lock_irq (&data->dev->lock);
 406         if (likely (data->ep != NULL)) {
 407                 switch (code) {
 408                 case GADGETFS_FIFO_STATUS:
 409                         status = usb_ep_fifo_status (data->ep);
 410                         break;
 411                 case GADGETFS_FIFO_FLUSH:
 412                         usb_ep_fifo_flush (data->ep);
 413                         break;
 414                 case GADGETFS_CLEAR_HALT:
 415                         status = usb_ep_clear_halt (data->ep);
 416                         break;
 417                 default:
 418                         status = -ENOTTY;
 419                 }
 420         } else
 421                 status = -ENODEV;
 422         spin_unlock_irq (&data->dev->lock);
 423         mutex_unlock(&data->lock);
 424         return status;
 425 }
 426
 427 /*----------------------------------------------------------------------*/
 428
 429 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 430
 431 struct kiocb_priv {
 432         struct usb_request      *req;
 433         struct ep_data          *epdata;
 434         struct kiocb            *iocb;
 435         struct mm_struct        *mm;
 436         struct work_struct      work;
 437         void                    *buf;
 438         struct iov_iter         to;
 439         const void              *to_free;
 440         unsigned                actual;
 441 };
 442
 443 static int ep_aio_cancel(struct kiocb *iocb)
 444 {
 445         struct kiocb_priv       *priv = iocb->private;
 446         struct ep_data          *epdata;
 447         int                     value;
 448
 449         local_irq_disable();
 450         epdata = priv->epdata;
 451         // spin_lock(&epdata->dev->lock);
 452         if (likely(epdata && epdata->ep && priv->req))
 453                 value = usb_ep_dequeue (epdata->ep, priv->req);
 454         else
 455                 value = -EINVAL;
 456         // spin_unlock(&epdata->dev->lock);
 457         local_irq_enable();
 458
 459         return value;
 460 }
 461
 462 static void ep_user_copy_worker(struct work_struct *work)
 463 {
 464         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 465         struct mm_struct *mm = priv->mm;
 466         struct kiocb *iocb = priv->iocb;
 467         size_t ret;
 468
 469         kthread_use_mm(mm);
 470         ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
 471         kthread_unuse_mm(mm);
 472         if (!ret)
 473                 ret = -EFAULT;
 474
 475         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 476         iocb->ki_complete(iocb, ret);
 477
 478         kfree(priv->buf);
 479         kfree(priv->to_free);
 480         kfree(priv);
 481 }
 482
 483 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 484 {
 485         struct kiocb            *iocb = req->context;
 486         struct kiocb_priv       *priv = iocb->private;
 487         struct ep_data          *epdata = priv->epdata;
 488
 489         /* lock against disconnect (and ideally, cancel) */
 490         spin_lock(&epdata->dev->lock);
 491         priv->req = NULL;
 492         priv->epdata = NULL;
 493
 494         /* if this was a write or a read returning no data then we
 495          * don't need to copy anything to userspace, so we can
 496          * complete the aio request immediately.
 497          */
 498         if (priv->to_free == NULL || unlikely(req->actual == 0)) {
 499                 kfree(req->buf);
 500                 kfree(priv->to_free);
 501                 kfree(priv);
 502                 iocb->private = NULL;
 503                 iocb->ki_complete(iocb,
 504                                 req->actual ? req->actual : (long)req->status);
 505         } else {
 506                 /* ep_copy_to_user() won't report both; we hide some faults */
 507                 if (unlikely(0 != req->status))
 508                         DBG(epdata->dev, "%s fault %d len %d\n",
 509                                 ep->name, req->status, req->actual);
 510
 511                 priv->buf = req->buf;
 512                 priv->actual = req->actual;
 513                 INIT_WORK(&priv->work, ep_user_copy_worker);
 514                 schedule_work(&priv->work);
 515         }
 516
 517         usb_ep_free_request(ep, req);
 518         spin_unlock(&epdata->dev->lock);
 519         put_ep(epdata);
 520 }
 521
 522 static ssize_t ep_aio(struct kiocb *iocb,
 523                       struct kiocb_priv *priv,
 524                       struct ep_data *epdata,
 525                       char *buf,
 526                       size_t len)
 527 {
 528         struct usb_request *req;
 529         ssize_t value;
 530
 531         iocb->private = priv;
 532         priv->iocb = iocb;
 533
 534         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 535         get_ep(epdata);
 536         priv->epdata = epdata;
 537         priv->actual = 0;
 538         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 539
 540         /* each kiocb is coupled to one usb_request, but we can't
 541          * allocate or submit those if the host disconnected.
 542          */
 543         spin_lock_irq(&epdata->dev->lock);
 544         value = -ENODEV;
 545         if (unlikely(epdata->ep == NULL))
 546                 goto fail;
 547
 548         req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 549         value = -ENOMEM;
 550         if (unlikely(!req))
 551                 goto fail;
 552
 553         priv->req = req;
 554         req->buf = buf;
 555         req->length = len;
 556         req->complete = ep_aio_complete;
 557         req->context = iocb;
 558         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 559         if (unlikely(0 != value)) {
 560                 usb_ep_free_request(epdata->ep, req);
 561                 goto fail;
 562         }
 563         spin_unlock_irq(&epdata->dev->lock);
 564         return -EIOCBQUEUED;
 565
 566 fail:
 567         spin_unlock_irq(&epdata->dev->lock);
 568         kfree(priv->to_free);
 569         kfree(priv);
 570         put_ep(epdata);
 571         return value;
 572 }
 573
 574 static ssize_t
 575 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 576 {
 577         struct file *file = iocb->ki_filp;
 578         struct ep_data *epdata = file->private_data;
 579         size_t len = iov_iter_count(to);
 580         ssize_t value;
 581         char *buf;
 582
 583         if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
 584                 return value;
 585
 586         /* halt any endpoint by doing a "wrong direction" i/o call */
 587         if (usb_endpoint_dir_in(&epdata->desc)) {
 588                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 589                     !is_sync_kiocb(iocb)) {
 590                         mutex_unlock(&epdata->lock);
 591                         return -EINVAL;
 592                 }
 593                 DBG (epdata->dev, "%s halt\n", epdata->name);
 594                 spin_lock_irq(&epdata->dev->lock);
 595                 if (likely(epdata->ep != NULL))
 596                         usb_ep_set_halt(epdata->ep);
 597                 spin_unlock_irq(&epdata->dev->lock);
 598                 mutex_unlock(&epdata->lock);
 599                 return -EBADMSG;
 600         }
 601
 602         buf = kmalloc(len, GFP_KERNEL);
 603         if (unlikely(!buf)) {
 604                 mutex_unlock(&epdata->lock);
 605                 return -ENOMEM;
 606         }
 607         if (is_sync_kiocb(iocb)) {
 608                 value = ep_io(epdata, buf, len);
 609                 if (value >= 0 && (copy_to_iter(buf, value, to) != value))
 610                         value = -EFAULT;
 611         } else {
 612                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 613                 value = -ENOMEM;
 614                 if (!priv)
 615                         goto fail;
 616                 priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
 617                 if (!iter_is_ubuf(&priv->to) && !priv->to_free) {
 618                         kfree(priv);
 619                         goto fail;
 620                 }
 621                 value = ep_aio(iocb, priv, epdata, buf, len);
 622                 if (value == -EIOCBQUEUED)
 623                         buf = NULL;
 624         }
 625 fail:
 626         kfree(buf);
 627         mutex_unlock(&epdata->lock);
 628         return value;
 629 }
 630
 631 static ssize_t ep_config(struct ep_data *, const char *, size_t);
 632
 633 static ssize_t
 634 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 635 {
 636         struct file *file = iocb->ki_filp;
 637         struct ep_data *epdata = file->private_data;
 638         size_t len = iov_iter_count(from);
 639         bool configured;
 640         ssize_t value;
 641         char *buf;
 642
 643         if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
 644                 return value;
 645
 646         configured = epdata->state == STATE_EP_ENABLED;
 647
 648         /* halt any endpoint by doing a "wrong direction" i/o call */
 649         if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
 650                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 651                     !is_sync_kiocb(iocb)) {
 652                         mutex_unlock(&epdata->lock);
 653                         return -EINVAL;
 654                 }
 655                 DBG (epdata->dev, "%s halt\n", epdata->name);
 656                 spin_lock_irq(&epdata->dev->lock);
 657                 if (likely(epdata->ep != NULL))
 658                         usb_ep_set_halt(epdata->ep);
 659                 spin_unlock_irq(&epdata->dev->lock);
 660                 mutex_unlock(&epdata->lock);
 661                 return -EBADMSG;
 662         }
 663
 664         buf = kmalloc(len, GFP_KERNEL);
 665         if (unlikely(!buf)) {
 666                 mutex_unlock(&epdata->lock);
 667                 return -ENOMEM;
 668         }
 669
 670         if (unlikely(!copy_from_iter_full(buf, len, from))) {
 671                 value = -EFAULT;
 672                 goto out;
 673         }
 674
 675         if (unlikely(!configured)) {
 676                 value = ep_config(epdata, buf, len);
 677         } else if (is_sync_kiocb(iocb)) {
 678                 value = ep_io(epdata, buf, len);
 679         } else {
 680                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 681                 value = -ENOMEM;
 682                 if (priv) {
 683                         value = ep_aio(iocb, priv, epdata, buf, len);
 684                         if (value == -EIOCBQUEUED)
 685                                 buf = NULL;
 686                 }
 687         }
 688 out:
 689         kfree(buf);
 690         mutex_unlock(&epdata->lock);
 691         return value;
 692 }
 693
 694 /*----------------------------------------------------------------------*/
 695
 696 /* used after endpoint configuration */
 697 static const struct file_operations ep_io_operations = {
 698         .owner =        THIS_MODULE,
 699
 700         .open =         ep_open,
 701         .release =      ep_release,
 702         .llseek =       no_llseek,
 703         .unlocked_ioctl = ep_ioctl,
 704         .read_iter =    ep_read_iter,
 705         .write_iter =   ep_write_iter,
 706 };
 707
 708 /* ENDPOINT INITIALIZATION
 709  *
 710  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 711  *     status = write (fd, descriptors, sizeof descriptors)
 712  *
 713  * That write establishes the endpoint configuration, configuring
 714  * the controller to process bulk, interrupt, or isochronous transfers
 715  * at the right maxpacket size, and so on.
 716  *
 717  * The descriptors are message type 1, identified by a host order u32
 718  * at the beginning of what's written.  Descriptor order is: full/low
 719  * speed descriptor, then optional high speed descriptor.
 720  */
 721 static ssize_t
 722 ep_config (struct ep_data *data, const char *buf, size_t len)
 723 {
 724         struct usb_ep           *ep;
 725         u32                     tag;
 726         int                     value, length = len;
 727
 728         if (data->state != STATE_EP_READY) {
 729                 value = -EL2HLT;
 730                 goto fail;
 731         }
 732
 733         value = len;
 734         if (len < USB_DT_ENDPOINT_SIZE + 4)
 735                 goto fail0;
 736
 737         /* we might need to change message format someday */
 738         memcpy(&tag, buf, 4);
 739         if (tag != 1) {
 740                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 741                 goto fail0;
 742         }
 743         buf += 4;
 744         len -= 4;
 745
 746         /* NOTE:  audio endpoint extensions not accepted here;
 747          * just don't include the extra bytes.
 748          */
 749
 750         /* full/low speed descriptor, then high speed */
 751         memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
 752         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 753                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 754                 goto fail0;
 755         if (len != USB_DT_ENDPOINT_SIZE) {
 756                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 757                         goto fail0;
 758                 memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 759                         USB_DT_ENDPOINT_SIZE);
 760                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 761                                 || data->hs_desc.bDescriptorType
 762                                         != USB_DT_ENDPOINT) {
 763                         DBG(data->dev, "config %s, bad hs length or type\n",
 764                                         data->name);
 765                         goto fail0;
 766                 }
 767         }
 768
 769         spin_lock_irq (&data->dev->lock);
 770         if (data->dev->state == STATE_DEV_UNBOUND) {
 771                 value = -ENOENT;
 772                 goto gone;
 773         } else {
 774                 ep = data->ep;
 775                 if (ep == NULL) {
 776                         value = -ENODEV;
 777                         goto gone;
 778                 }
 779         }
 780         switch (data->dev->gadget->speed) {
 781         case USB_SPEED_LOW:
 782         case USB_SPEED_FULL:
 783                 ep->desc = &data->desc;
 784                 break;
 785         case USB_SPEED_HIGH:
 786                 /* fails if caller didn't provide that descriptor... */
 787                 ep->desc = &data->hs_desc;
 788                 break;
 789         default:
 790                 DBG(data->dev, "unconnected, %s init abandoned\n",
 791                                 data->name);
 792                 value = -EINVAL;
 793                 goto gone;
 794         }
 795         value = usb_ep_enable(ep);
 796         if (value == 0) {
 797                 data->state = STATE_EP_ENABLED;
 798                 value = length;
 799         }
 800 gone:
 801         spin_unlock_irq (&data->dev->lock);
 802         if (value < 0) {
 803 fail:
 804                 data->desc.bDescriptorType = 0;
 805                 data->hs_desc.bDescriptorType = 0;
 806         }
 807         return value;
 808 fail0:
 809         value = -EINVAL;
 810         goto fail;
 811 }
 812
 813 static int
 814 ep_open (struct inode *inode, struct file *fd)
 815 {
 816         struct ep_data          *data = inode->i_private;
 817         int                     value = -EBUSY;
 818
 819         if (mutex_lock_interruptible(&data->lock) != 0)
 820                 return -EINTR;
 821         spin_lock_irq (&data->dev->lock);
 822         if (data->dev->state == STATE_DEV_UNBOUND)
 823                 value = -ENOENT;
 824         else if (data->state == STATE_EP_DISABLED) {
 825                 value = 0;
 826                 data->state = STATE_EP_READY;
 827                 get_ep (data);
 828                 fd->private_data = data;
 829                 VDEBUG (data->dev, "%s ready\n", data->name);
 830         } else
 831                 DBG (data->dev, "%s state %d\n",
 832                         data->name, data->state);
 833         spin_unlock_irq (&data->dev->lock);
 834         mutex_unlock(&data->lock);
 835         return value;
 836 }
 837
 838 /*----------------------------------------------------------------------*/
 839
 840 /* EP0 IMPLEMENTATION can be partly in userspace.
 841  *
 842  * Drivers that use this facility receive various events, including
 843  * control requests the kernel doesn't handle.  Drivers that don't
 844  * use this facility may be too simple-minded for real applications.
 845  */
 846
 847 static inline void ep0_readable (struct dev_data *dev)
 848 {
 849         wake_up (&dev->wait);
 850         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 851 }
 852
 853 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 854 {
 855         struct dev_data         *dev = ep->driver_data;
 856
 857         if (req->buf != dev->rbuf) {
 858                 kfree(req->buf);
 859                 req->buf = dev->rbuf;
 860         }
 861         req->complete = epio_complete;
 862         dev->setup_out_ready = 0;
 863 }
 864
 865 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 866 {
 867         struct dev_data         *dev = ep->driver_data;
 868         unsigned long           flags;
 869         int                     free = 1;
 870
 871         /* for control OUT, data must still get to userspace */
 872         spin_lock_irqsave(&dev->lock, flags);
 873         if (!dev->setup_in) {
 874                 dev->setup_out_error = (req->status != 0);
 875                 if (!dev->setup_out_error)
 876                         free = 0;
 877                 dev->setup_out_ready = 1;
 878                 ep0_readable (dev);
 879         }
 880
 881         /* clean up as appropriate */
 882         if (free && req->buf != &dev->rbuf)
 883                 clean_req (ep, req);
 884         req->complete = epio_complete;
 885         spin_unlock_irqrestore(&dev->lock, flags);
 886 }
 887
 888 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 889 {
 890         struct dev_data *dev = ep->driver_data;
 891
 892         if (dev->setup_out_ready) {
 893                 DBG (dev, "ep0 request busy!\n");
 894                 return -EBUSY;
 895         }
 896         if (len > sizeof (dev->rbuf))
 897                 req->buf = kmalloc(len, GFP_ATOMIC);
 898         if (req->buf == NULL) {
 899                 req->buf = dev->rbuf;
 900                 return -ENOMEM;
 901         }
 902         req->complete = ep0_complete;
 903         req->length = len;
 904         req->zero = 0;
 905         return 0;
 906 }
 907
 908 static ssize_t
 909 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 910 {
 911         struct dev_data                 *dev = fd->private_data;
 912         ssize_t                         retval;
 913         enum ep0_state                  state;
 914
 915         spin_lock_irq (&dev->lock);
 916         if (dev->state <= STATE_DEV_OPENED) {
 917                 retval = -EINVAL;
 918                 goto done;
 919         }
 920
 921         /* report fd mode change before acting on it */
 922         if (dev->setup_abort) {
 923                 dev->setup_abort = 0;
 924                 retval = -EIDRM;
 925                 goto done;
 926         }
 927
 928         /* control DATA stage */
 929         if ((state = dev->state) == STATE_DEV_SETUP) {
 930
 931                 if (dev->setup_in) {            /* stall IN */
 932                         VDEBUG(dev, "ep0in stall\n");
 933                         (void) usb_ep_set_halt (dev->gadget->ep0);
 934                         retval = -EL2HLT;
 935                         dev->state = STATE_DEV_CONNECTED;
 936
 937                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
 938                         struct usb_ep           *ep = dev->gadget->ep0;
 939                         struct usb_request      *req = dev->req;
 940
 941                         if ((retval = setup_req (ep, req, 0)) == 0) {
 942                                 ++dev->udc_usage;
 943                                 spin_unlock_irq (&dev->lock);
 944                                 retval = usb_ep_queue (ep, req, GFP_KERNEL);
 945                                 spin_lock_irq (&dev->lock);
 946                                 --dev->udc_usage;
 947                         }
 948                         dev->state = STATE_DEV_CONNECTED;
 949
 950                         /* assume that was SET_CONFIGURATION */
 951                         if (dev->current_config) {
 952                                 unsigned power;
 953
 954                                 if (gadget_is_dualspeed(dev->gadget)
 955                                                 && (dev->gadget->speed
 956                                                         == USB_SPEED_HIGH))
 957                                         power = dev->hs_config->bMaxPower;
 958                                 else
 959                                         power = dev->config->bMaxPower;
 960                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
 961                         }
 962
 963                 } else {                        /* collect OUT data */
 964                         if ((fd->f_flags & O_NONBLOCK) != 0
 965                                         && !dev->setup_out_ready) {
 966                                 retval = -EAGAIN;
 967                                 goto done;
 968                         }
 969                         spin_unlock_irq (&dev->lock);
 970                         retval = wait_event_interruptible (dev->wait,
 971                                         dev->setup_out_ready != 0);
 972
 973                         /* FIXME state could change from under us */
 974                         spin_lock_irq (&dev->lock);
 975                         if (retval)
 976                                 goto done;
 977
 978                         if (dev->state != STATE_DEV_SETUP) {
 979                                 retval = -ECANCELED;
 980                                 goto done;
 981                         }
 982                         dev->state = STATE_DEV_CONNECTED;
 983
 984                         if (dev->setup_out_error)
 985                                 retval = -EIO;
 986                         else {
 987                                 len = min (len, (size_t)dev->req->actual);
 988                                 ++dev->udc_usage;
 989                                 spin_unlock_irq(&dev->lock);
 990                                 if (copy_to_user (buf, dev->req->buf, len))
 991                                         retval = -EFAULT;
 992                                 else
 993                                         retval = len;
 994                                 spin_lock_irq(&dev->lock);
 995                                 --dev->udc_usage;
 996                                 clean_req (dev->gadget->ep0, dev->req);
 997                                 /* NOTE userspace can't yet choose to stall */
 998                         }
 999                 }
1000                 goto done;
1001         }
1002
1003         /* else normal: return event data */
1004         if (len < sizeof dev->event [0]) {
1005                 retval = -EINVAL;
1006                 goto done;
1007         }
1008         len -= len % sizeof (struct usb_gadgetfs_event);
1009         dev->usermode_setup = 1;
1010
1011 scan:
1012         /* return queued events right away */
1013         if (dev->ev_next != 0) {
1014                 unsigned                i, n;
1015
1016                 n = len / sizeof (struct usb_gadgetfs_event);
1017                 if (dev->ev_next < n)
1018                         n = dev->ev_next;
1019
1020                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1021                 for (i = 0; i < n; i++) {
1022                         if (dev->event [i].type == GADGETFS_SETUP) {
1023                                 dev->state = STATE_DEV_SETUP;
1024                                 n = i + 1;
1025                                 break;
1026                         }
1027                 }
1028                 spin_unlock_irq (&dev->lock);
1029                 len = n * sizeof (struct usb_gadgetfs_event);
1030                 if (copy_to_user (buf, &dev->event, len))
1031                         retval = -EFAULT;
1032                 else
1033                         retval = len;
1034                 if (len > 0) {
1035                         /* NOTE this doesn't guard against broken drivers;
1036                          * concurrent ep0 readers may lose events.
1037                          */
1038                         spin_lock_irq (&dev->lock);
1039                         if (dev->ev_next > n) {
1040                                 memmove(&dev->event[0], &dev->event[n],
1041                                         sizeof (struct usb_gadgetfs_event)
1042                                                 * (dev->ev_next - n));
1043                         }
1044                         dev->ev_next -= n;
1045                         spin_unlock_irq (&dev->lock);
1046                 }
1047                 return retval;
1048         }
1049         if (fd->f_flags & O_NONBLOCK) {
1050                 retval = -EAGAIN;
1051                 goto done;
1052         }
1053
1054         switch (state) {
1055         default:
1056                 DBG (dev, "fail %s, state %d\n", __func__, state);
1057                 retval = -ESRCH;
1058                 break;
1059         case STATE_DEV_UNCONNECTED:
1060         case STATE_DEV_CONNECTED:
1061                 spin_unlock_irq (&dev->lock);
1062                 DBG (dev, "%s wait\n", __func__);
1063
1064                 /* wait for events */
1065                 retval = wait_event_interruptible (dev->wait,
1066                                 dev->ev_next != 0);
1067                 if (retval < 0)
1068                         return retval;
1069                 spin_lock_irq (&dev->lock);
1070                 goto scan;
1071         }
1072
1073 done:
1074         spin_unlock_irq (&dev->lock);
1075         return retval;
1076 }
1077
1078 static struct usb_gadgetfs_event *
1079 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1080 {
1081         struct usb_gadgetfs_event       *event;
1082         unsigned                        i;
1083
1084         switch (type) {
1085         /* these events purge the queue */
1086         case GADGETFS_DISCONNECT:
1087                 if (dev->state == STATE_DEV_SETUP)
1088                         dev->setup_abort = 1;
1089                 fallthrough;
1090         case GADGETFS_CONNECT:
1091                 dev->ev_next = 0;
1092                 break;
1093         case GADGETFS_SETUP:            /* previous request timed out */
1094         case GADGETFS_SUSPEND:          /* same effect */
1095                 /* these events can't be repeated */
1096                 for (i = 0; i != dev->ev_next; i++) {
1097                         if (dev->event [i].type != type)
1098                                 continue;
1099                         DBG(dev, "discard old event[%d] %d\n", i, type);
1100                         dev->ev_next--;
1101                         if (i == dev->ev_next)
1102                                 break;
1103                         /* indices start at zero, for simplicity */
1104                         memmove (&dev->event [i], &dev->event [i + 1],
1105                                 sizeof (struct usb_gadgetfs_event)
1106                                         * (dev->ev_next - i));
1107                 }
1108                 break;
1109         default:
1110                 BUG ();
1111         }
1112         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1113         event = &dev->event [dev->ev_next++];
1114         BUG_ON (dev->ev_next > N_EVENT);
1115         memset (event, 0, sizeof *event);
1116         event->type = type;
1117         return event;
1118 }
1119
1120 static ssize_t
1121 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1122 {
1123         struct dev_data         *dev = fd->private_data;
1124         ssize_t                 retval = -ESRCH;
1125
1126         /* report fd mode change before acting on it */
1127         if (dev->setup_abort) {
1128                 dev->setup_abort = 0;
1129                 retval = -EIDRM;
1130
1131         /* data and/or status stage for control request */
1132         } else if (dev->state == STATE_DEV_SETUP) {
1133
1134                 len = min_t(size_t, len, dev->setup_wLength);
1135                 if (dev->setup_in) {
1136                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1137                         if (retval == 0) {
1138                                 dev->state = STATE_DEV_CONNECTED;
1139                                 ++dev->udc_usage;
1140                                 spin_unlock_irq (&dev->lock);
1141                                 if (copy_from_user (dev->req->buf, buf, len))
1142                                         retval = -EFAULT;
1143                                 else {
1144                                         if (len < dev->setup_wLength)
1145                                                 dev->req->zero = 1;
1146                                         retval = usb_ep_queue (
1147                                                 dev->gadget->ep0, dev->req,
1148                                                 GFP_KERNEL);
1149                                 }
1150                                 spin_lock_irq(&dev->lock);
1151                                 --dev->udc_usage;
1152                                 if (retval < 0) {
1153                                         clean_req (dev->gadget->ep0, dev->req);
1154                                 } else
1155                                         retval = len;
1156
1157                                 return retval;
1158                         }
1159
1160                 /* can stall some OUT transfers */
1161                 } else if (dev->setup_can_stall) {
1162                         VDEBUG(dev, "ep0out stall\n");
1163                         (void) usb_ep_set_halt (dev->gadget->ep0);
1164                         retval = -EL2HLT;
1165                         dev->state = STATE_DEV_CONNECTED;
1166                 } else {
1167                         DBG(dev, "bogus ep0out stall!\n");
1168                 }
1169         } else
1170                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1171
1172         return retval;
1173 }
1174
1175 static int
1176 ep0_fasync (int f, struct file *fd, int on)
1177 {
1178         struct dev_data         *dev = fd->private_data;
1179         // caller must F_SETOWN before signal delivery happens
1180         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1181         return fasync_helper (f, fd, on, &dev->fasync);
1182 }
1183
1184 static struct usb_gadget_driver gadgetfs_driver;
1185
1186 static int
1187 dev_release (struct inode *inode, struct file *fd)
1188 {
1189         struct dev_data         *dev = fd->private_data;
1190
1191         /* closing ep0 === shutdown all */
1192
1193         if (dev->gadget_registered) {
1194                 usb_gadget_unregister_driver (&gadgetfs_driver);
1195                 dev->gadget_registered = false;
1196         }
1197
1198         /* at this point "good" hardware has disconnected the
1199          * device from USB; the host won't see it any more.
1200          * alternatively, all host requests will time out.
1201          */
1202
1203         kfree (dev->buf);
1204         dev->buf = NULL;
1205
1206         /* other endpoints were all decoupled from this device */
1207         spin_lock_irq(&dev->lock);
1208         dev->state = STATE_DEV_DISABLED;
1209         spin_unlock_irq(&dev->lock);
1210
1211         put_dev (dev);
1212         return 0;
1213 }
1214
1215 static __poll_t
1216 ep0_poll (struct file *fd, poll_table *wait)
1217 {
1218         struct dev_data         *dev = fd->private_data;
1219         __poll_t                mask = 0;
1220
1221         if (dev->state <= STATE_DEV_OPENED)
1222                 return DEFAULT_POLLMASK;
1223
1224         poll_wait(fd, &dev->wait, wait);
1225
1226         spin_lock_irq(&dev->lock);
1227
1228         /* report fd mode change before acting on it */
1229         if (dev->setup_abort) {
1230                 dev->setup_abort = 0;
1231                 mask = EPOLLHUP;
1232                 goto out;
1233         }
1234
1235         if (dev->state == STATE_DEV_SETUP) {
1236                 if (dev->setup_in || dev->setup_can_stall)
1237                         mask = EPOLLOUT;
1238         } else {
1239                 if (dev->ev_next != 0)
1240                         mask = EPOLLIN;
1241         }
1242 out:
1243         spin_unlock_irq(&dev->lock);
1244         return mask;
1245 }
1246
1247 static long gadget_dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1248 {
1249         struct dev_data         *dev = fd->private_data;
1250         struct usb_gadget       *gadget = dev->gadget;
1251         long ret = -ENOTTY;
1252
1253         spin_lock_irq(&dev->lock);
1254         if (dev->state == STATE_DEV_OPENED ||
1255                         dev->state == STATE_DEV_UNBOUND) {
1256                 /* Not bound to a UDC */
1257         } else if (gadget->ops->ioctl) {
1258                 ++dev->udc_usage;
1259                 spin_unlock_irq(&dev->lock);
1260
1261                 ret = gadget->ops->ioctl (gadget, code, value);
1262
1263                 spin_lock_irq(&dev->lock);
1264                 --dev->udc_usage;
1265         }
1266         spin_unlock_irq(&dev->lock);
1267
1268         return ret;
1269 }
1270
1271 /*----------------------------------------------------------------------*/
1272
1273 /* The in-kernel gadget driver handles most ep0 issues, in particular
1274  * enumerating the single configuration (as provided from user space).
1275  *
1276  * Unrecognized ep0 requests may be handled in user space.
1277  */
1278
1279 static void make_qualifier (struct dev_data *dev)
1280 {
1281         struct usb_qualifier_descriptor         qual;
1282         struct usb_device_descriptor            *desc;
1283
1284         qual.bLength = sizeof qual;
1285         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1286         qual.bcdUSB = cpu_to_le16 (0x0200);
1287
1288         desc = dev->dev;
1289         qual.bDeviceClass = desc->bDeviceClass;
1290         qual.bDeviceSubClass = desc->bDeviceSubClass;
1291         qual.bDeviceProtocol = desc->bDeviceProtocol;
1292
1293         /* assumes ep0 uses the same value for both speeds ... */
1294         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1295
1296         qual.bNumConfigurations = 1;
1297         qual.bRESERVED = 0;
1298
1299         memcpy (dev->rbuf, &qual, sizeof qual);
1300 }
1301
1302 static int
1303 config_buf (struct dev_data *dev, u8 type, unsigned index)
1304 {
1305         int             len;
1306         int             hs = 0;
1307
1308         /* only one configuration */
1309         if (index > 0)
1310                 return -EINVAL;
1311
1312         if (gadget_is_dualspeed(dev->gadget)) {
1313                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1314                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1315                         hs = !hs;
1316         }
1317         if (hs) {
1318                 dev->req->buf = dev->hs_config;
1319                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1320         } else {
1321                 dev->req->buf = dev->config;
1322                 len = le16_to_cpu(dev->config->wTotalLength);
1323         }
1324         ((u8 *)dev->req->buf) [1] = type;
1325         return len;
1326 }
1327
1328 static int
1329 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1330 {
1331         struct dev_data                 *dev = get_gadget_data (gadget);
1332         struct usb_request              *req = dev->req;
1333         int                             value = -EOPNOTSUPP;
1334         struct usb_gadgetfs_event       *event;
1335         u16                             w_value = le16_to_cpu(ctrl->wValue);
1336         u16                             w_length = le16_to_cpu(ctrl->wLength);
1337
1338         if (w_length > RBUF_SIZE) {
1339                 if (ctrl->bRequestType & USB_DIR_IN) {
1340                         /* Cast away the const, we are going to overwrite on purpose. */
1341                         __le16 *temp = (__le16 *)&ctrl->wLength;
1342
1343                         *temp = cpu_to_le16(RBUF_SIZE);
1344                         w_length = RBUF_SIZE;
1345                 } else {
1346                         return value;
1347                 }
1348         }
1349
1350         spin_lock (&dev->lock);
1351         dev->setup_abort = 0;
1352         if (dev->state == STATE_DEV_UNCONNECTED) {
1353                 if (gadget_is_dualspeed(gadget)
1354                                 && gadget->speed == USB_SPEED_HIGH
1355                                 && dev->hs_config == NULL) {
1356                         spin_unlock(&dev->lock);
1357                         ERROR (dev, "no high speed config??\n");
1358                         return -EINVAL;
1359                 }
1360
1361                 dev->state = STATE_DEV_CONNECTED;
1362
1363                 INFO (dev, "connected\n");
1364                 event = next_event (dev, GADGETFS_CONNECT);
1365                 event->u.speed = gadget->speed;
1366                 ep0_readable (dev);
1367
1368         /* host may have given up waiting for response.  we can miss control
1369          * requests handled lower down (device/endpoint status and features);
1370          * then ep0_{read,write} will report the wrong status. controller
1371          * driver will have aborted pending i/o.
1372          */
1373         } else if (dev->state == STATE_DEV_SETUP)
1374                 dev->setup_abort = 1;
1375
1376         req->buf = dev->rbuf;
1377         req->context = NULL;
1378         switch (ctrl->bRequest) {
1379
1380         case USB_REQ_GET_DESCRIPTOR:
1381                 if (ctrl->bRequestType != USB_DIR_IN)
1382                         goto unrecognized;
1383                 switch (w_value >> 8) {
1384
1385                 case USB_DT_DEVICE:
1386                         value = min (w_length, (u16) sizeof *dev->dev);
1387                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1388                         req->buf = dev->dev;
1389                         break;
1390                 case USB_DT_DEVICE_QUALIFIER:
1391                         if (!dev->hs_config)
1392                                 break;
1393                         value = min (w_length, (u16)
1394                                 sizeof (struct usb_qualifier_descriptor));
1395                         make_qualifier (dev);
1396                         break;
1397                 case USB_DT_OTHER_SPEED_CONFIG:
1398                 case USB_DT_CONFIG:
1399                         value = config_buf (dev,
1400                                         w_value >> 8,
1401                                         w_value & 0xff);
1402                         if (value >= 0)
1403                                 value = min (w_length, (u16) value);
1404                         break;
1405                 case USB_DT_STRING:
1406                         goto unrecognized;
1407
1408                 default:                // all others are errors
1409                         break;
1410                 }
1411                 break;
1412
1413         /* currently one config, two speeds */
1414         case USB_REQ_SET_CONFIGURATION:
1415                 if (ctrl->bRequestType != 0)
1416                         goto unrecognized;
1417                 if (0 == (u8) w_value) {
1418                         value = 0;
1419                         dev->current_config = 0;
1420                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1421                         // user mode expected to disable endpoints
1422                 } else {
1423                         u8      config, power;
1424
1425                         if (gadget_is_dualspeed(gadget)
1426                                         && gadget->speed == USB_SPEED_HIGH) {
1427                                 config = dev->hs_config->bConfigurationValue;
1428                                 power = dev->hs_config->bMaxPower;
1429                         } else {
1430                                 config = dev->config->bConfigurationValue;
1431                                 power = dev->config->bMaxPower;
1432                         }
1433
1434                         if (config == (u8) w_value) {
1435                                 value = 0;
1436                                 dev->current_config = config;
1437                                 usb_gadget_vbus_draw(gadget, 2 * power);
1438                         }
1439                 }
1440
1441                 /* report SET_CONFIGURATION like any other control request,
1442                  * except that usermode may not stall this.  the next
1443                  * request mustn't be allowed start until this finishes:
1444                  * endpoints and threads set up, etc.
1445                  *
1446                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1447                  * has bad/racey automagic that prevents synchronizing here.
1448                  * even kernel mode drivers often miss them.
1449                  */
1450                 if (value == 0) {
1451                         INFO (dev, "configuration #%d\n", dev->current_config);
1452                         usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1453                         if (dev->usermode_setup) {
1454                                 dev->setup_can_stall = 0;
1455                                 goto delegate;
1456                         }
1457                 }
1458                 break;
1459
1460 #ifndef CONFIG_USB_PXA25X
1461         /* PXA automagically handles this request too */
1462         case USB_REQ_GET_CONFIGURATION:
1463                 if (ctrl->bRequestType != 0x80)
1464                         goto unrecognized;
1465                 *(u8 *)req->buf = dev->current_config;
1466                 value = min (w_length, (u16) 1);
1467                 break;
1468 #endif
1469
1470         default:
1471 unrecognized:
1472                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1473                         dev->usermode_setup ? "delegate" : "fail",
1474                         ctrl->bRequestType, ctrl->bRequest,
1475                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1476
1477                 /* if there's an ep0 reader, don't stall */
1478                 if (dev->usermode_setup) {
1479                         dev->setup_can_stall = 1;
1480 delegate:
1481                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1482                                                 ? 1 : 0;
1483                         dev->setup_wLength = w_length;
1484                         dev->setup_out_ready = 0;
1485                         dev->setup_out_error = 0;
1486
1487                         /* read DATA stage for OUT right away */
1488                         if (unlikely (!dev->setup_in && w_length)) {
1489                                 value = setup_req (gadget->ep0, dev->req,
1490                                                         w_length);
1491                                 if (value < 0)
1492                                         break;
1493
1494                                 ++dev->udc_usage;
1495                                 spin_unlock (&dev->lock);
1496                                 value = usb_ep_queue (gadget->ep0, dev->req,
1497                                                         GFP_KERNEL);
1498                                 spin_lock (&dev->lock);
1499                                 --dev->udc_usage;
1500                                 if (value < 0) {
1501                                         clean_req (gadget->ep0, dev->req);
1502                                         break;
1503                                 }
1504
1505                                 /* we can't currently stall these */
1506                                 dev->setup_can_stall = 0;
1507                         }
1508
1509                         /* state changes when reader collects event */
1510                         event = next_event (dev, GADGETFS_SETUP);
1511                         event->u.setup = *ctrl;
1512                         ep0_readable (dev);
1513                         spin_unlock (&dev->lock);
1514                         return 0;
1515                 }
1516         }
1517
1518         /* proceed with data transfer and status phases? */
1519         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1520                 req->length = value;
1521                 req->zero = value < w_length;
1522
1523                 ++dev->udc_usage;
1524                 spin_unlock (&dev->lock);
1525                 value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1526                 spin_lock(&dev->lock);
1527                 --dev->udc_usage;
1528                 spin_unlock(&dev->lock);
1529                 if (value < 0) {
1530                         DBG (dev, "ep_queue --> %d\n", value);
1531                         req->status = 0;
1532                 }
1533                 return value;
1534         }
1535
1536         /* device stalls when value < 0 */
1537         spin_unlock (&dev->lock);
1538         return value;
1539 }
1540
1541 static void destroy_ep_files (struct dev_data *dev)
1542 {
1543         DBG (dev, "%s %d\n", __func__, dev->state);
1544
1545         /* dev->state must prevent interference */
1546         spin_lock_irq (&dev->lock);
1547         while (!list_empty(&dev->epfiles)) {
1548                 struct ep_data  *ep;
1549                 struct inode    *parent;
1550                 struct dentry   *dentry;
1551
1552                 /* break link to FS */
1553                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1554                 list_del_init (&ep->epfiles);
1555                 spin_unlock_irq (&dev->lock);
1556
1557                 dentry = ep->dentry;
1558                 ep->dentry = NULL;
1559                 parent = d_inode(dentry->d_parent);
1560
1561                 /* break link to controller */
1562                 mutex_lock(&ep->lock);
1563                 if (ep->state == STATE_EP_ENABLED)
1564                         (void) usb_ep_disable (ep->ep);
1565                 ep->state = STATE_EP_UNBOUND;
1566                 usb_ep_free_request (ep->ep, ep->req);
1567                 ep->ep = NULL;
1568                 mutex_unlock(&ep->lock);
1569
1570                 wake_up (&ep->wait);
1571                 put_ep (ep);
1572
1573                 /* break link to dcache */
1574                 inode_lock(parent);
1575                 d_delete (dentry);
1576                 dput (dentry);
1577                 inode_unlock(parent);
1578
1579                 spin_lock_irq (&dev->lock);
1580         }
1581         spin_unlock_irq (&dev->lock);
1582 }
1583
1584
1585 static struct dentry *
1586 gadgetfs_create_file (struct super_block *sb, char const *name,
1587                 void *data, const struct file_operations *fops);
1588
1589 static int activate_ep_files (struct dev_data *dev)
1590 {
1591         struct usb_ep   *ep;
1592         struct ep_data  *data;
1593
1594         gadget_for_each_ep (ep, dev->gadget) {
1595
1596                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1597                 if (!data)
1598                         goto enomem0;
1599                 data->state = STATE_EP_DISABLED;
1600                 mutex_init(&data->lock);
1601                 init_waitqueue_head (&data->wait);
1602
1603                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1604                 refcount_set (&data->count, 1);
1605                 data->dev = dev;
1606                 get_dev (dev);
1607
1608                 data->ep = ep;
1609                 ep->driver_data = data;
1610
1611                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1612                 if (!data->req)
1613                         goto enomem1;
1614
1615                 data->dentry = gadgetfs_create_file (dev->sb, data->name,
1616                                 data, &ep_io_operations);
1617                 if (!data->dentry)
1618                         goto enomem2;
1619                 list_add_tail (&data->epfiles, &dev->epfiles);
1620         }
1621         return 0;
1622
1623 enomem2:
1624         usb_ep_free_request (ep, data->req);
1625 enomem1:
1626         put_dev (dev);
1627         kfree (data);
1628 enomem0:
1629         DBG (dev, "%s enomem\n", __func__);
1630         destroy_ep_files (dev);
1631         return -ENOMEM;
1632 }
1633
1634 static void
1635 gadgetfs_unbind (struct usb_gadget *gadget)
1636 {
1637         struct dev_data         *dev = get_gadget_data (gadget);
1638
1639         DBG (dev, "%s\n", __func__);
1640
1641         spin_lock_irq (&dev->lock);
1642         dev->state = STATE_DEV_UNBOUND;
1643         while (dev->udc_usage > 0) {
1644                 spin_unlock_irq(&dev->lock);
1645                 usleep_range(1000, 2000);
1646                 spin_lock_irq(&dev->lock);
1647         }
1648         spin_unlock_irq (&dev->lock);
1649
1650         destroy_ep_files (dev);
1651         gadget->ep0->driver_data = NULL;
1652         set_gadget_data (gadget, NULL);
1653
1654         /* we've already been disconnected ... no i/o is active */
1655         if (dev->req)
1656                 usb_ep_free_request (gadget->ep0, dev->req);
1657         DBG (dev, "%s done\n", __func__);
1658         put_dev (dev);
1659 }
1660
1661 static struct dev_data          *the_device;
1662
1663 static int gadgetfs_bind(struct usb_gadget *gadget,
1664                 struct usb_gadget_driver *driver)
1665 {
1666         struct dev_data         *dev = the_device;
1667
1668         if (!dev)
1669                 return -ESRCH;
1670         if (0 != strcmp (CHIP, gadget->name)) {
1671                 pr_err("%s expected %s controller not %s\n",
1672                         shortname, CHIP, gadget->name);
1673                 return -ENODEV;
1674         }
1675
1676         set_gadget_data (gadget, dev);
1677         dev->gadget = gadget;
1678         gadget->ep0->driver_data = dev;
1679
1680         /* preallocate control response and buffer */
1681         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1682         if (!dev->req)
1683                 goto enomem;
1684         dev->req->context = NULL;
1685         dev->req->complete = epio_complete;
1686
1687         if (activate_ep_files (dev) < 0)
1688                 goto enomem;
1689
1690         INFO (dev, "bound to %s driver\n", gadget->name);
1691         spin_lock_irq(&dev->lock);
1692         dev->state = STATE_DEV_UNCONNECTED;
1693         spin_unlock_irq(&dev->lock);
1694         get_dev (dev);
1695         return 0;
1696
1697 enomem:
1698         gadgetfs_unbind (gadget);
1699         return -ENOMEM;
1700 }
1701
1702 static void
1703 gadgetfs_disconnect (struct usb_gadget *gadget)
1704 {
1705         struct dev_data         *dev = get_gadget_data (gadget);
1706         unsigned long           flags;
1707
1708         spin_lock_irqsave (&dev->lock, flags);
1709         if (dev->state == STATE_DEV_UNCONNECTED)
1710                 goto exit;
1711         dev->state = STATE_DEV_UNCONNECTED;
1712
1713         INFO (dev, "disconnected\n");
1714         next_event (dev, GADGETFS_DISCONNECT);
1715         ep0_readable (dev);
1716 exit:
1717         spin_unlock_irqrestore (&dev->lock, flags);
1718 }
1719
1720 static void
1721 gadgetfs_suspend (struct usb_gadget *gadget)
1722 {
1723         struct dev_data         *dev = get_gadget_data (gadget);
1724         unsigned long           flags;
1725
1726         INFO (dev, "suspended from state %d\n", dev->state);
1727         spin_lock_irqsave(&dev->lock, flags);
1728         switch (dev->state) {
1729         case STATE_DEV_SETUP:           // VERY odd... host died??
1730         case STATE_DEV_CONNECTED:
1731         case STATE_DEV_UNCONNECTED:
1732                 next_event (dev, GADGETFS_SUSPEND);
1733                 ep0_readable (dev);
1734                 fallthrough;
1735         default:
1736                 break;
1737         }
1738         spin_unlock_irqrestore(&dev->lock, flags);
1739 }
1740
1741 static struct usb_gadget_driver gadgetfs_driver = {
1742         .function       = (char *) driver_desc,
1743         .bind           = gadgetfs_bind,
1744         .unbind         = gadgetfs_unbind,
1745         .setup          = gadgetfs_setup,
1746         .reset          = gadgetfs_disconnect,
1747         .disconnect     = gadgetfs_disconnect,
1748         .suspend        = gadgetfs_suspend,
1749
1750         .driver = {
1751                 .name           = shortname,
1752         },
1753 };
1754
1755 /*----------------------------------------------------------------------*/
1756 /* DEVICE INITIALIZATION
1757  *
1758  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1759  *     status = write (fd, descriptors, sizeof descriptors)
1760  *
1761  * That write establishes the device configuration, so the kernel can
1762  * bind to the controller ... guaranteeing it can handle enumeration
1763  * at all necessary speeds.  Descriptor order is:
1764  *
1765  * . message tag (u32, host order) ... for now, must be zero; it
1766  *      would change to support features like multi-config devices
1767  * . full/low speed config ... all wTotalLength bytes (with interface,
1768  *      class, altsetting, endpoint, and other descriptors)
1769  * . high speed config ... all descriptors, for high speed operation;
1770  *      this one's optional except for high-speed hardware
1771  * . device descriptor
1772  *
1773  * Endpoints are not yet enabled. Drivers must wait until device
1774  * configuration and interface altsetting changes create
1775  * the need to configure (or unconfigure) them.
1776  *
1777  * After initialization, the device stays active for as long as that
1778  * $CHIP file is open.  Events must then be read from that descriptor,
1779  * such as configuration notifications.
1780  */
1781
1782 static int is_valid_config(struct usb_config_descriptor *config,
1783                 unsigned int total)
1784 {
1785         return config->bDescriptorType == USB_DT_CONFIG
1786                 && config->bLength == USB_DT_CONFIG_SIZE
1787                 && total >= USB_DT_CONFIG_SIZE
1788                 && config->bConfigurationValue != 0
1789                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1790                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1791         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1792         /* FIXME check lengths: walk to end */
1793 }
1794
1795 static ssize_t
1796 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1797 {
1798         struct dev_data         *dev = fd->private_data;
1799         ssize_t                 value, length = len;
1800         unsigned                total;
1801         u32                     tag;
1802         char                    *kbuf;
1803
1804         spin_lock_irq(&dev->lock);
1805         if (dev->state > STATE_DEV_OPENED) {
1806                 value = ep0_write(fd, buf, len, ptr);
1807                 spin_unlock_irq(&dev->lock);
1808                 return value;
1809         }
1810         spin_unlock_irq(&dev->lock);
1811
1812         if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1813             (len > PAGE_SIZE * 4))
1814                 return -EINVAL;
1815
1816         /* we might need to change message format someday */
1817         if (copy_from_user (&tag, buf, 4))
1818                 return -EFAULT;
1819         if (tag != 0)
1820                 return -EINVAL;
1821         buf += 4;
1822         length -= 4;
1823
1824         kbuf = memdup_user(buf, length);
1825         if (IS_ERR(kbuf))
1826                 return PTR_ERR(kbuf);
1827
1828         spin_lock_irq (&dev->lock);
1829         value = -EINVAL;
1830         if (dev->buf) {
1831                 spin_unlock_irq(&dev->lock);
1832                 kfree(kbuf);
1833                 return value;
1834         }
1835         dev->buf = kbuf;
1836
1837         /* full or low speed config */
1838         dev->config = (void *) kbuf;
1839         total = le16_to_cpu(dev->config->wTotalLength);
1840         if (!is_valid_config(dev->config, total) ||
1841                         total > length - USB_DT_DEVICE_SIZE)
1842                 goto fail;
1843         kbuf += total;
1844         length -= total;
1845
1846         /* optional high speed config */
1847         if (kbuf [1] == USB_DT_CONFIG) {
1848                 dev->hs_config = (void *) kbuf;
1849                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1850                 if (!is_valid_config(dev->hs_config, total) ||
1851                                 total > length - USB_DT_DEVICE_SIZE)
1852                         goto fail;
1853                 kbuf += total;
1854                 length -= total;
1855         } else {
1856                 dev->hs_config = NULL;
1857         }
1858
1859         /* could support multiple configs, using another encoding! */
1860
1861         /* device descriptor (tweaked for paranoia) */
1862         if (length != USB_DT_DEVICE_SIZE)
1863                 goto fail;
1864         dev->dev = (void *)kbuf;
1865         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1866                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1867                         || dev->dev->bNumConfigurations != 1)
1868                 goto fail;
1869         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1870
1871         /* triggers gadgetfs_bind(); then we can enumerate. */
1872         spin_unlock_irq (&dev->lock);
1873         if (dev->hs_config)
1874                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1875         else
1876                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1877
1878         value = usb_gadget_register_driver(&gadgetfs_driver);
1879         if (value != 0) {
1880                 spin_lock_irq(&dev->lock);
1881                 goto fail;
1882         } else {
1883                 /* at this point "good" hardware has for the first time
1884                  * let the USB the host see us.  alternatively, if users
1885                  * unplug/replug that will clear all the error state.
1886                  *
1887                  * note:  everything running before here was guaranteed
1888                  * to choke driver model style diagnostics.  from here
1889                  * on, they can work ... except in cleanup paths that
1890                  * kick in after the ep0 descriptor is closed.
1891                  */
1892                 value = len;
1893                 dev->gadget_registered = true;
1894         }
1895         return value;
1896
1897 fail:
1898         dev->config = NULL;
1899         dev->hs_config = NULL;
1900         dev->dev = NULL;
1901         spin_unlock_irq (&dev->lock);
1902         pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev);
1903         kfree (dev->buf);
1904         dev->buf = NULL;
1905         return value;
1906 }
1907
1908 static int
1909 gadget_dev_open (struct inode *inode, struct file *fd)
1910 {
1911         struct dev_data         *dev = inode->i_private;
1912         int                     value = -EBUSY;
1913
1914         spin_lock_irq(&dev->lock);
1915         if (dev->state == STATE_DEV_DISABLED) {
1916                 dev->ev_next = 0;
1917                 dev->state = STATE_DEV_OPENED;
1918                 fd->private_data = dev;
1919                 get_dev (dev);
1920                 value = 0;
1921         }
1922         spin_unlock_irq(&dev->lock);
1923         return value;
1924 }
1925
1926 static const struct file_operations ep0_operations = {
1927         .llseek =       no_llseek,
1928
1929         .open =         gadget_dev_open,
1930         .read =         ep0_read,
1931         .write =        dev_config,
1932         .fasync =       ep0_fasync,
1933         .poll =         ep0_poll,
1934         .unlocked_ioctl = gadget_dev_ioctl,
1935         .release =      dev_release,
1936 };
1937
1938 /*----------------------------------------------------------------------*/
1939
1940 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1941  *
1942  * Mounting the filesystem creates a controller file, used first for
1943  * device configuration then later for event monitoring.
1944  */
1945
1946
1947 /* FIXME PAM etc could set this security policy without mount options
1948  * if epfiles inherited ownership and permissons from ep0 ...
1949  */
1950
1951 static unsigned default_uid;
1952 static unsigned default_gid;
1953 static unsigned default_perm = S_IRUSR | S_IWUSR;
1954
1955 module_param (default_uid, uint, 0644);
1956 module_param (default_gid, uint, 0644);
1957 module_param (default_perm, uint, 0644);
1958
1959
1960 static struct inode *
1961 gadgetfs_make_inode (struct super_block *sb,
1962                 void *data, const struct file_operations *fops,
1963                 int mode)
1964 {
1965         struct inode *inode = new_inode (sb);
1966
1967         if (inode) {
1968                 inode->i_ino = get_next_ino();
1969                 inode->i_mode = mode;
1970                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
1971                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
1972                 inode->i_atime = inode->i_mtime = inode->i_ctime
1973                                 = current_time(inode);
1974                 inode->i_private = data;
1975                 inode->i_fop = fops;
1976         }
1977         return inode;
1978 }
1979
1980 /* creates in fs root directory, so non-renamable and non-linkable.
1981  * so inode and dentry are paired, until device reconfig.
1982  */
1983 static struct dentry *
1984 gadgetfs_create_file (struct super_block *sb, char const *name,
1985                 void *data, const struct file_operations *fops)
1986 {
1987         struct dentry   *dentry;
1988         struct inode    *inode;
1989
1990         dentry = d_alloc_name(sb->s_root, name);
1991         if (!dentry)
1992                 return NULL;
1993
1994         inode = gadgetfs_make_inode (sb, data, fops,
1995                         S_IFREG | (default_perm & S_IRWXUGO));
1996         if (!inode) {
1997                 dput(dentry);
1998                 return NULL;
1999         }
2000         d_add (dentry, inode);
2001         return dentry;
2002 }
2003
2004 static const struct super_operations gadget_fs_operations = {
2005         .statfs =       simple_statfs,
2006         .drop_inode =   generic_delete_inode,
2007 };
2008
2009 static int
2010 gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc)
2011 {
2012         struct inode    *inode;
2013         struct dev_data *dev;
2014         int             rc;
2015
2016         mutex_lock(&sb_mutex);
2017
2018         if (the_device) {
2019                 rc = -ESRCH;
2020                 goto Done;
2021         }
2022
2023         CHIP = usb_get_gadget_udc_name();
2024         if (!CHIP) {
2025                 rc = -ENODEV;
2026                 goto Done;
2027         }
2028
2029         /* superblock */
2030         sb->s_blocksize = PAGE_SIZE;
2031         sb->s_blocksize_bits = PAGE_SHIFT;
2032         sb->s_magic = GADGETFS_MAGIC;
2033         sb->s_op = &gadget_fs_operations;
2034         sb->s_time_gran = 1;
2035
2036         /* root inode */
2037         inode = gadgetfs_make_inode (sb,
2038                         NULL, &simple_dir_operations,
2039                         S_IFDIR | S_IRUGO | S_IXUGO);
2040         if (!inode)
2041                 goto Enomem;
2042         inode->i_op = &simple_dir_inode_operations;
2043         if (!(sb->s_root = d_make_root (inode)))
2044                 goto Enomem;
2045
2046         /* the ep0 file is named after the controller we expect;
2047          * user mode code can use it for sanity checks, like we do.
2048          */
2049         dev = dev_new ();
2050         if (!dev)
2051                 goto Enomem;
2052
2053         dev->sb = sb;
2054         dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2055         if (!dev->dentry) {
2056                 put_dev(dev);
2057                 goto Enomem;
2058         }
2059
2060         /* other endpoint files are available after hardware setup,
2061          * from binding to a controller.
2062          */
2063         the_device = dev;
2064         rc = 0;
2065         goto Done;
2066
2067  Enomem:
2068         kfree(CHIP);
2069         CHIP = NULL;
2070         rc = -ENOMEM;
2071
2072  Done:
2073         mutex_unlock(&sb_mutex);
2074         return rc;
2075 }
2076
2077 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2078 static int gadgetfs_get_tree(struct fs_context *fc)
2079 {
2080         return get_tree_single(fc, gadgetfs_fill_super);
2081 }
2082
2083 static const struct fs_context_operations gadgetfs_context_ops = {
2084         .get_tree       = gadgetfs_get_tree,
2085 };
2086
2087 static int gadgetfs_init_fs_context(struct fs_context *fc)
2088 {
2089         fc->ops = &gadgetfs_context_ops;
2090         return 0;
2091 }
2092
2093 static void
2094 gadgetfs_kill_sb (struct super_block *sb)
2095 {
2096         mutex_lock(&sb_mutex);
2097         kill_litter_super (sb);
2098         if (the_device) {
2099                 put_dev (the_device);
2100                 the_device = NULL;
2101         }
2102         kfree(CHIP);
2103         CHIP = NULL;
2104         mutex_unlock(&sb_mutex);
2105 }
2106
2107 /*----------------------------------------------------------------------*/
2108
2109 static struct file_system_type gadgetfs_type = {
2110         .owner          = THIS_MODULE,
2111         .name           = shortname,
2112         .init_fs_context = gadgetfs_init_fs_context,
2113         .kill_sb        = gadgetfs_kill_sb,
2114 };
2115 MODULE_ALIAS_FS("gadgetfs");
2116
2117 /*----------------------------------------------------------------------*/
2118
2119 static int __init gadgetfs_init (void)
2120 {
2121         int status;
2122
2123         status = register_filesystem (&gadgetfs_type);
2124         if (status == 0)
2125                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2126                         shortname, driver_desc);
2127         return status;
2128 }
2129 module_init (gadgetfs_init);
2130
2131 static void __exit gadgetfs_cleanup (void)
2132 {
2133         pr_debug ("unregister %s\n", shortname);
2134         unregister_filesystem (&gadgetfs_type);
2135 }
2136 module_exit (gadgetfs_cleanup);
2137