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 #include <linux/usb/composite.h> /* for USB_GADGET_DELAYED_STATUS */
  35
  36 /* Undef helpers from linux/usb/composite.h as gadgetfs redefines them */
  37 #undef DBG
  38 #undef ERROR
  39 #undef INFO
  40
  41
  42 /*
  43  * The gadgetfs API maps each endpoint to a file descriptor so that you
  44  * can use standard synchronous read/write calls for I/O.  There's some
  45  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  46  * drivers show how this works in practice.  You can also use AIO to
  47  * eliminate I/O gaps between requests, to help when streaming data.
  48  *
  49  * Key parts that must be USB-specific are protocols defining how the
  50  * read/write operations relate to the hardware state machines.  There
  51  * are two types of files.  One type is for the device, implementing ep0.
  52  * The other type is for each IN or OUT endpoint.  In both cases, the
  53  * user mode driver must configure the hardware before using it.
  54  *
  55  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  56  *   (by writing configuration and device descriptors).  Afterwards it
  57  *   may serve as a source of device events, used to handle all control
  58  *   requests other than basic enumeration.
  59  *
  60  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  61  *   called when each /dev/gadget/ep* file is configured (by writing
  62  *   endpoint descriptors).  Afterwards these files are used to write()
  63  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  64  *   direction" request is issued (like reading an IN endpoint).
  65  *
  66  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  67  * not possible on all hardware.  For example, precise fault handling with
  68  * respect to data left in endpoint fifos after aborted operations; or
  69  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  70  */
  71
  72 #define DRIVER_DESC     "USB Gadget filesystem"
  73 #define DRIVER_VERSION  "24 Aug 2004"
  74
  75 static const char driver_desc [] = DRIVER_DESC;
  76 static const char shortname [] = "gadgetfs";
  77
  78 MODULE_DESCRIPTION (DRIVER_DESC);
  79 MODULE_AUTHOR ("David Brownell");
  80 MODULE_LICENSE ("GPL");
  81
  82 static int ep_open(struct inode *, struct file *);
  83
  84
  85 /*----------------------------------------------------------------------*/
  86
  87 #define GADGETFS_MAGIC          0xaee71ee7
  88
  89 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  90 enum ep0_state {
  91         /* DISABLED is the initial state. */
  92         STATE_DEV_DISABLED = 0,
  93
  94         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  95          * ep0/device i/o modes and binding to the controller.  Driver
  96          * must always write descriptors to initialize the device, then
  97          * the device becomes UNCONNECTED until enumeration.
  98          */
  99         STATE_DEV_OPENED,
 100
 101         /* From then on, ep0 fd is in either of two basic modes:
 102          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
 103          * - SETUP: read/write will transfer control data and succeed;
 104          *   or if "wrong direction", performs protocol stall
 105          */
 106         STATE_DEV_UNCONNECTED,
 107         STATE_DEV_CONNECTED,
 108         STATE_DEV_SETUP,
 109
 110         /* UNBOUND means the driver closed ep0, so the device won't be
 111          * accessible again (DEV_DISABLED) until all fds are closed.
 112          */
 113         STATE_DEV_UNBOUND,
 114 };
 115
 116 /* enough for the whole queue: most events invalidate others */
 117 #define N_EVENT                 5
 118
 119 #define RBUF_SIZE               256
 120
 121 struct dev_data {
 122         spinlock_t                      lock;
 123         refcount_t                      count;
 124         int                             udc_usage;
 125         enum ep0_state                  state;          /* P: lock */
 126         struct usb_gadgetfs_event       event [N_EVENT];
 127         unsigned                        ev_next;
 128         struct fasync_struct            *fasync;
 129         u8                              current_config;
 130
 131         /* drivers reading ep0 MUST handle control requests (SETUP)
 132          * reported that way; else the host will time out.
 133          */
 134         unsigned                        usermode_setup : 1,
 135                                         setup_in : 1,
 136                                         setup_can_stall : 1,
 137                                         setup_out_ready : 1,
 138                                         setup_out_error : 1,
 139                                         setup_abort : 1,
 140                                         gadget_registered : 1;
 141         unsigned                        setup_wLength;
 142
 143         /* the rest is basically write-once */
 144         struct usb_config_descriptor    *config, *hs_config;
 145         struct usb_device_descriptor    *dev;
 146         struct usb_request              *req;
 147         struct usb_gadget               *gadget;
 148         struct list_head                epfiles;
 149         void                            *buf;
 150         wait_queue_head_t               wait;
 151         struct super_block              *sb;
 152         struct dentry                   *dentry;
 153
 154         /* except this scratch i/o buffer for ep0 */
 155         u8                              rbuf[RBUF_SIZE];
 156 };
 157
 158 static inline void get_dev (struct dev_data *data)
 159 {
 160         refcount_inc (&data->count);
 161 }
 162
 163 static void put_dev (struct dev_data *data)
 164 {
 165         if (likely (!refcount_dec_and_test (&data->count)))
 166                 return;
 167         /* needs no more cleanup */
 168         BUG_ON (waitqueue_active (&data->wait));
 169         kfree (data);
 170 }
 171
 172 static struct dev_data *dev_new (void)
 173 {
 174         struct dev_data         *dev;
 175
 176         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 177         if (!dev)
 178                 return NULL;
 179         dev->state = STATE_DEV_DISABLED;
 180         refcount_set (&dev->count, 1);
 181         spin_lock_init (&dev->lock);
 182         INIT_LIST_HEAD (&dev->epfiles);
 183         init_waitqueue_head (&dev->wait);
 184         return dev;
 185 }
 186
 187 /*----------------------------------------------------------------------*/
 188
 189 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 190 enum ep_state {
 191         STATE_EP_DISABLED = 0,
 192         STATE_EP_READY,
 193         STATE_EP_ENABLED,
 194         STATE_EP_UNBOUND,
 195 };
 196
 197 struct ep_data {
 198         struct mutex                    lock;
 199         enum ep_state                   state;
 200         refcount_t                      count;
 201         struct dev_data                 *dev;
 202         /* must hold dev->lock before accessing ep or req */
 203         struct usb_ep                   *ep;
 204         struct usb_request              *req;
 205         ssize_t                         status;
 206         char                            name [16];
 207         struct usb_endpoint_descriptor  desc, hs_desc;
 208         struct list_head                epfiles;
 209         wait_queue_head_t               wait;
 210         struct dentry                   *dentry;
 211 };
 212
 213 static inline void get_ep (struct ep_data *data)
 214 {
 215         refcount_inc (&data->count);
 216 }
 217
 218 static void put_ep (struct ep_data *data)
 219 {
 220         if (likely (!refcount_dec_and_test (&data->count)))
 221                 return;
 222         put_dev (data->dev);
 223         /* needs no more cleanup */
 224         BUG_ON (!list_empty (&data->epfiles));
 225         BUG_ON (waitqueue_active (&data->wait));
 226         kfree (data);
 227 }
 228
 229 /*----------------------------------------------------------------------*/
 230
 231 /* most "how to use the hardware" policy choices are in userspace:
 232  * mapping endpoint roles (which the driver needs) to the capabilities
 233  * which the usb controller has.  most of those capabilities are exposed
 234  * implicitly, starting with the driver name and then endpoint names.
 235  */
 236
 237 static const char *CHIP;
 238 static DEFINE_MUTEX(sb_mutex);          /* Serialize superblock operations */
 239
 240 /*----------------------------------------------------------------------*/
 241
 242 /* NOTE:  don't use dev_printk calls before binding to the gadget
 243  * at the end of ep0 configuration, or after unbind.
 244  */
 245
 246 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 247 #define xprintk(d,level,fmt,args...) \
 248         printk(level "%s: " fmt , shortname , ## args)
 249
 250 #ifdef DEBUG
 251 #define DBG(dev,fmt,args...) \
 252         xprintk(dev , KERN_DEBUG , fmt , ## args)
 253 #else
 254 #define DBG(dev,fmt,args...) \
 255         do { } while (0)
 256 #endif /* DEBUG */
 257
 258 #ifdef VERBOSE_DEBUG
 259 #define VDEBUG  DBG
 260 #else
 261 #define VDEBUG(dev,fmt,args...) \
 262         do { } while (0)
 263 #endif /* DEBUG */
 264
 265 #define ERROR(dev,fmt,args...) \
 266         xprintk(dev , KERN_ERR , fmt , ## args)
 267 #define INFO(dev,fmt,args...) \
 268         xprintk(dev , KERN_INFO , fmt , ## args)
 269
 270
 271 /*----------------------------------------------------------------------*/
 272
 273 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 274  *
 275  * After opening, configure non-control endpoints.  Then use normal
 276  * stream read() and write() requests; and maybe ioctl() to get more
 277  * precise FIFO status when recovering from cancellation.
 278  */
 279
 280 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 281 {
 282         struct ep_data  *epdata = ep->driver_data;
 283
 284         if (!req->context)
 285                 return;
 286         if (req->status)
 287                 epdata->status = req->status;
 288         else
 289                 epdata->status = req->actual;
 290         complete ((struct completion *)req->context);
 291 }
 292
 293 /* tasklock endpoint, returning when it's connected.
 294  * still need dev->lock to use epdata->ep.
 295  */
 296 static int
 297 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 298 {
 299         int     val;
 300
 301         if (f_flags & O_NONBLOCK) {
 302                 if (!mutex_trylock(&epdata->lock))
 303                         goto nonblock;
 304                 if (epdata->state != STATE_EP_ENABLED &&
 305                     (!is_write || epdata->state != STATE_EP_READY)) {
 306                         mutex_unlock(&epdata->lock);
 307 nonblock:
 308                         val = -EAGAIN;
 309                 } else
 310                         val = 0;
 311                 return val;
 312         }
 313
 314         val = mutex_lock_interruptible(&epdata->lock);
 315         if (val < 0)
 316                 return val;
 317
 318         switch (epdata->state) {
 319         case STATE_EP_ENABLED:
 320                 return 0;
 321         case STATE_EP_READY:                    /* not configured yet */
 322                 if (is_write)
 323                         return 0;
 324                 fallthrough;
 325         case STATE_EP_UNBOUND:                  /* clean disconnect */
 326                 break;
 327         // case STATE_EP_DISABLED:              /* "can't happen" */
 328         default:                                /* error! */
 329                 pr_debug ("%s: ep %p not available, state %d\n",
 330                                 shortname, epdata, epdata->state);
 331         }
 332         mutex_unlock(&epdata->lock);
 333         return -ENODEV;
 334 }
 335
 336 static ssize_t
 337 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 338 {
 339         DECLARE_COMPLETION_ONSTACK (done);
 340         int value;
 341
 342         spin_lock_irq (&epdata->dev->lock);
 343         if (likely (epdata->ep != NULL)) {
 344                 struct usb_request      *req = epdata->req;
 345
 346                 req->context = &done;
 347                 req->complete = epio_complete;
 348                 req->buf = buf;
 349                 req->length = len;
 350                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 351         } else
 352                 value = -ENODEV;
 353         spin_unlock_irq (&epdata->dev->lock);
 354
 355         if (likely (value == 0)) {
 356                 value = wait_for_completion_interruptible(&done);
 357                 if (value != 0) {
 358                         spin_lock_irq (&epdata->dev->lock);
 359                         if (likely (epdata->ep != NULL)) {
 360                                 DBG (epdata->dev, "%s i/o interrupted\n",
 361                                                 epdata->name);
 362                                 usb_ep_dequeue (epdata->ep, epdata->req);
 363                                 spin_unlock_irq (&epdata->dev->lock);
 364
 365                                 wait_for_completion(&done);
 366                                 if (epdata->status == -ECONNRESET)
 367                                         epdata->status = -EINTR;
 368                         } else {
 369                                 spin_unlock_irq (&epdata->dev->lock);
 370
 371                                 DBG (epdata->dev, "endpoint gone\n");
 372                                 wait_for_completion(&done);
 373                                 epdata->status = -ENODEV;
 374                         }
 375                 }
 376                 return epdata->status;
 377         }
 378         return value;
 379 }
 380
 381 static int
 382 ep_release (struct inode *inode, struct file *fd)
 383 {
 384         struct ep_data          *data = fd->private_data;
 385         int value;
 386
 387         value = mutex_lock_interruptible(&data->lock);
 388         if (value < 0)
 389                 return value;
 390
 391         /* clean up if this can be reopened */
 392         if (data->state != STATE_EP_UNBOUND) {
 393                 data->state = STATE_EP_DISABLED;
 394                 data->desc.bDescriptorType = 0;
 395                 data->hs_desc.bDescriptorType = 0;
 396                 usb_ep_disable(data->ep);
 397         }
 398         mutex_unlock(&data->lock);
 399         put_ep (data);
 400         return 0;
 401 }
 402
 403 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 404 {
 405         struct ep_data          *data = fd->private_data;
 406         int                     status;
 407
 408         if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
 409                 return status;
 410
 411         spin_lock_irq (&data->dev->lock);
 412         if (likely (data->ep != NULL)) {
 413                 switch (code) {
 414                 case GADGETFS_FIFO_STATUS:
 415                         status = usb_ep_fifo_status (data->ep);
 416                         break;
 417                 case GADGETFS_FIFO_FLUSH:
 418                         usb_ep_fifo_flush (data->ep);
 419                         break;
 420                 case GADGETFS_CLEAR_HALT:
 421                         status = usb_ep_clear_halt (data->ep);
 422                         break;
 423                 default:
 424                         status = -ENOTTY;
 425                 }
 426         } else
 427                 status = -ENODEV;
 428         spin_unlock_irq (&data->dev->lock);
 429         mutex_unlock(&data->lock);
 430         return status;
 431 }
 432
 433 /*----------------------------------------------------------------------*/
 434
 435 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 436
 437 struct kiocb_priv {
 438         struct usb_request      *req;
 439         struct ep_data          *epdata;
 440         struct kiocb            *iocb;
 441         struct mm_struct        *mm;
 442         struct work_struct      work;
 443         void                    *buf;
 444         struct iov_iter         to;
 445         const void              *to_free;
 446         unsigned                actual;
 447 };
 448
 449 static int ep_aio_cancel(struct kiocb *iocb)
 450 {
 451         struct kiocb_priv       *priv = iocb->private;
 452         struct ep_data          *epdata;
 453         int                     value;
 454
 455         local_irq_disable();
 456         epdata = priv->epdata;
 457         // spin_lock(&epdata->dev->lock);
 458         if (likely(epdata && epdata->ep && priv->req))
 459                 value = usb_ep_dequeue (epdata->ep, priv->req);
 460         else
 461                 value = -EINVAL;
 462         // spin_unlock(&epdata->dev->lock);
 463         local_irq_enable();
 464
 465         return value;
 466 }
 467
 468 static void ep_user_copy_worker(struct work_struct *work)
 469 {
 470         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 471         struct mm_struct *mm = priv->mm;
 472         struct kiocb *iocb = priv->iocb;
 473         size_t ret;
 474
 475         kthread_use_mm(mm);
 476         ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
 477         kthread_unuse_mm(mm);
 478         if (!ret)
 479                 ret = -EFAULT;
 480
 481         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 482         iocb->ki_complete(iocb, ret);
 483
 484         kfree(priv->buf);
 485         kfree(priv->to_free);
 486         kfree(priv);
 487 }
 488
 489 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 490 {
 491         struct kiocb            *iocb = req->context;
 492         struct kiocb_priv       *priv = iocb->private;
 493         struct ep_data          *epdata = priv->epdata;
 494
 495         /* lock against disconnect (and ideally, cancel) */
 496         spin_lock(&epdata->dev->lock);
 497         priv->req = NULL;
 498         priv->epdata = NULL;
 499
 500         /* if this was a write or a read returning no data then we
 501          * don't need to copy anything to userspace, so we can
 502          * complete the aio request immediately.
 503          */
 504         if (priv->to_free == NULL || unlikely(req->actual == 0)) {
 505                 kfree(req->buf);
 506                 kfree(priv->to_free);
 507                 kfree(priv);
 508                 iocb->private = NULL;
 509                 iocb->ki_complete(iocb,
 510                                 req->actual ? req->actual : (long)req->status);
 511         } else {
 512                 /* ep_copy_to_user() won't report both; we hide some faults */
 513                 if (unlikely(0 != req->status))
 514                         DBG(epdata->dev, "%s fault %d len %d\n",
 515                                 ep->name, req->status, req->actual);
 516
 517                 priv->buf = req->buf;
 518                 priv->actual = req->actual;
 519                 INIT_WORK(&priv->work, ep_user_copy_worker);
 520                 schedule_work(&priv->work);
 521         }
 522
 523         usb_ep_free_request(ep, req);
 524         spin_unlock(&epdata->dev->lock);
 525         put_ep(epdata);
 526 }
 527
 528 static ssize_t ep_aio(struct kiocb *iocb,
 529                       struct kiocb_priv *priv,
 530                       struct ep_data *epdata,
 531                       char *buf,
 532                       size_t len)
 533 {
 534         struct usb_request *req;
 535         ssize_t value;
 536
 537         iocb->private = priv;
 538         priv->iocb = iocb;
 539
 540         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 541         get_ep(epdata);
 542         priv->epdata = epdata;
 543         priv->actual = 0;
 544         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 545
 546         /* each kiocb is coupled to one usb_request, but we can't
 547          * allocate or submit those if the host disconnected.
 548          */
 549         spin_lock_irq(&epdata->dev->lock);
 550         value = -ENODEV;
 551         if (unlikely(epdata->ep == NULL))
 552                 goto fail;
 553
 554         req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 555         value = -ENOMEM;
 556         if (unlikely(!req))
 557                 goto fail;
 558
 559         priv->req = req;
 560         req->buf = buf;
 561         req->length = len;
 562         req->complete = ep_aio_complete;
 563         req->context = iocb;
 564         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 565         if (unlikely(0 != value)) {
 566                 usb_ep_free_request(epdata->ep, req);
 567                 goto fail;
 568         }
 569         spin_unlock_irq(&epdata->dev->lock);
 570         return -EIOCBQUEUED;
 571
 572 fail:
 573         spin_unlock_irq(&epdata->dev->lock);
 574         kfree(priv->to_free);
 575         kfree(priv);
 576         put_ep(epdata);
 577         return value;
 578 }
 579
 580 static ssize_t
 581 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 582 {
 583         struct file *file = iocb->ki_filp;
 584         struct ep_data *epdata = file->private_data;
 585         size_t len = iov_iter_count(to);
 586         ssize_t value;
 587         char *buf;
 588
 589         if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
 590                 return value;
 591
 592         /* halt any endpoint by doing a "wrong direction" i/o call */
 593         if (usb_endpoint_dir_in(&epdata->desc)) {
 594                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 595                     !is_sync_kiocb(iocb)) {
 596                         mutex_unlock(&epdata->lock);
 597                         return -EINVAL;
 598                 }
 599                 DBG (epdata->dev, "%s halt\n", epdata->name);
 600                 spin_lock_irq(&epdata->dev->lock);
 601                 if (likely(epdata->ep != NULL))
 602                         usb_ep_set_halt(epdata->ep);
 603                 spin_unlock_irq(&epdata->dev->lock);
 604                 mutex_unlock(&epdata->lock);
 605                 return -EBADMSG;
 606         }
 607
 608         buf = kmalloc(len, GFP_KERNEL);
 609         if (unlikely(!buf)) {
 610                 mutex_unlock(&epdata->lock);
 611                 return -ENOMEM;
 612         }
 613         if (is_sync_kiocb(iocb)) {
 614                 value = ep_io(epdata, buf, len);
 615                 if (value >= 0 && (copy_to_iter(buf, value, to) != value))
 616                         value = -EFAULT;
 617         } else {
 618                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 619                 value = -ENOMEM;
 620                 if (!priv)
 621                         goto fail;
 622                 priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
 623                 if (!iter_is_ubuf(&priv->to) && !priv->to_free) {
 624                         kfree(priv);
 625                         goto fail;
 626                 }
 627                 value = ep_aio(iocb, priv, epdata, buf, len);
 628                 if (value == -EIOCBQUEUED)
 629                         buf = NULL;
 630         }
 631 fail:
 632         kfree(buf);
 633         mutex_unlock(&epdata->lock);
 634         return value;
 635 }
 636
 637 static ssize_t ep_config(struct ep_data *, const char *, size_t);
 638
 639 static ssize_t
 640 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 641 {
 642         struct file *file = iocb->ki_filp;
 643         struct ep_data *epdata = file->private_data;
 644         size_t len = iov_iter_count(from);
 645         bool configured;
 646         ssize_t value;
 647         char *buf;
 648
 649         if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
 650                 return value;
 651
 652         configured = epdata->state == STATE_EP_ENABLED;
 653
 654         /* halt any endpoint by doing a "wrong direction" i/o call */
 655         if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
 656                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 657                     !is_sync_kiocb(iocb)) {
 658                         mutex_unlock(&epdata->lock);
 659                         return -EINVAL;
 660                 }
 661                 DBG (epdata->dev, "%s halt\n", epdata->name);
 662                 spin_lock_irq(&epdata->dev->lock);
 663                 if (likely(epdata->ep != NULL))
 664                         usb_ep_set_halt(epdata->ep);
 665                 spin_unlock_irq(&epdata->dev->lock);
 666                 mutex_unlock(&epdata->lock);
 667                 return -EBADMSG;
 668         }
 669
 670         buf = kmalloc(len, GFP_KERNEL);
 671         if (unlikely(!buf)) {
 672                 mutex_unlock(&epdata->lock);
 673                 return -ENOMEM;
 674         }
 675
 676         if (unlikely(!copy_from_iter_full(buf, len, from))) {
 677                 value = -EFAULT;
 678                 goto out;
 679         }
 680
 681         if (unlikely(!configured)) {
 682                 value = ep_config(epdata, buf, len);
 683         } else if (is_sync_kiocb(iocb)) {
 684                 value = ep_io(epdata, buf, len);
 685         } else {
 686                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 687                 value = -ENOMEM;
 688                 if (priv) {
 689                         value = ep_aio(iocb, priv, epdata, buf, len);
 690                         if (value == -EIOCBQUEUED)
 691                                 buf = NULL;
 692                 }
 693         }
 694 out:
 695         kfree(buf);
 696         mutex_unlock(&epdata->lock);
 697         return value;
 698 }
 699
 700 /*----------------------------------------------------------------------*/
 701
 702 /* used after endpoint configuration */
 703 static const struct file_operations ep_io_operations = {
 704         .owner =        THIS_MODULE,
 705
 706         .open =         ep_open,
 707         .release =      ep_release,
 708         .llseek =       no_llseek,
 709         .unlocked_ioctl = ep_ioctl,
 710         .read_iter =    ep_read_iter,
 711         .write_iter =   ep_write_iter,
 712 };
 713
 714 /* ENDPOINT INITIALIZATION
 715  *
 716  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 717  *     status = write (fd, descriptors, sizeof descriptors)
 718  *
 719  * That write establishes the endpoint configuration, configuring
 720  * the controller to process bulk, interrupt, or isochronous transfers
 721  * at the right maxpacket size, and so on.
 722  *
 723  * The descriptors are message type 1, identified by a host order u32
 724  * at the beginning of what's written.  Descriptor order is: full/low
 725  * speed descriptor, then optional high speed descriptor.
 726  */
 727 static ssize_t
 728 ep_config (struct ep_data *data, const char *buf, size_t len)
 729 {
 730         struct usb_ep           *ep;
 731         u32                     tag;
 732         int                     value, length = len;
 733
 734         if (data->state != STATE_EP_READY) {
 735                 value = -EL2HLT;
 736                 goto fail;
 737         }
 738
 739         value = len;
 740         if (len < USB_DT_ENDPOINT_SIZE + 4)
 741                 goto fail0;
 742
 743         /* we might need to change message format someday */
 744         memcpy(&tag, buf, 4);
 745         if (tag != 1) {
 746                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 747                 goto fail0;
 748         }
 749         buf += 4;
 750         len -= 4;
 751
 752         /* NOTE:  audio endpoint extensions not accepted here;
 753          * just don't include the extra bytes.
 754          */
 755
 756         /* full/low speed descriptor, then high speed */
 757         memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
 758         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 759                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 760                 goto fail0;
 761         if (len != USB_DT_ENDPOINT_SIZE) {
 762                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 763                         goto fail0;
 764                 memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 765                         USB_DT_ENDPOINT_SIZE);
 766                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 767                                 || data->hs_desc.bDescriptorType
 768                                         != USB_DT_ENDPOINT) {
 769                         DBG(data->dev, "config %s, bad hs length or type\n",
 770                                         data->name);
 771                         goto fail0;
 772                 }
 773         }
 774
 775         spin_lock_irq (&data->dev->lock);
 776         if (data->dev->state == STATE_DEV_UNBOUND) {
 777                 value = -ENOENT;
 778                 goto gone;
 779         } else {
 780                 ep = data->ep;
 781                 if (ep == NULL) {
 782                         value = -ENODEV;
 783                         goto gone;
 784                 }
 785         }
 786         switch (data->dev->gadget->speed) {
 787         case USB_SPEED_LOW:
 788         case USB_SPEED_FULL:
 789                 ep->desc = &data->desc;
 790                 break;
 791         case USB_SPEED_HIGH:
 792                 /* fails if caller didn't provide that descriptor... */
 793                 ep->desc = &data->hs_desc;
 794                 break;
 795         default:
 796                 DBG(data->dev, "unconnected, %s init abandoned\n",
 797                                 data->name);
 798                 value = -EINVAL;
 799                 goto gone;
 800         }
 801         value = usb_ep_enable(ep);
 802         if (value == 0) {
 803                 data->state = STATE_EP_ENABLED;
 804                 value = length;
 805         }
 806 gone:
 807         spin_unlock_irq (&data->dev->lock);
 808         if (value < 0) {
 809 fail:
 810                 data->desc.bDescriptorType = 0;
 811                 data->hs_desc.bDescriptorType = 0;
 812         }
 813         return value;
 814 fail0:
 815         value = -EINVAL;
 816         goto fail;
 817 }
 818
 819 static int
 820 ep_open (struct inode *inode, struct file *fd)
 821 {
 822         struct ep_data          *data = inode->i_private;
 823         int                     value = -EBUSY;
 824
 825         if (mutex_lock_interruptible(&data->lock) != 0)
 826                 return -EINTR;
 827         spin_lock_irq (&data->dev->lock);
 828         if (data->dev->state == STATE_DEV_UNBOUND)
 829                 value = -ENOENT;
 830         else if (data->state == STATE_EP_DISABLED) {
 831                 value = 0;
 832                 data->state = STATE_EP_READY;
 833                 get_ep (data);
 834                 fd->private_data = data;
 835                 VDEBUG (data->dev, "%s ready\n", data->name);
 836         } else
 837                 DBG (data->dev, "%s state %d\n",
 838                         data->name, data->state);
 839         spin_unlock_irq (&data->dev->lock);
 840         mutex_unlock(&data->lock);
 841         return value;
 842 }
 843
 844 /*----------------------------------------------------------------------*/
 845
 846 /* EP0 IMPLEMENTATION can be partly in userspace.
 847  *
 848  * Drivers that use this facility receive various events, including
 849  * control requests the kernel doesn't handle.  Drivers that don't
 850  * use this facility may be too simple-minded for real applications.
 851  */
 852
 853 static inline void ep0_readable (struct dev_data *dev)
 854 {
 855         wake_up (&dev->wait);
 856         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 857 }
 858
 859 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 860 {
 861         struct dev_data         *dev = ep->driver_data;
 862
 863         if (req->buf != dev->rbuf) {
 864                 kfree(req->buf);
 865                 req->buf = dev->rbuf;
 866         }
 867         req->complete = epio_complete;
 868         dev->setup_out_ready = 0;
 869 }
 870
 871 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 872 {
 873         struct dev_data         *dev = ep->driver_data;
 874         unsigned long           flags;
 875         int                     free = 1;
 876
 877         /* for control OUT, data must still get to userspace */
 878         spin_lock_irqsave(&dev->lock, flags);
 879         if (!dev->setup_in) {
 880                 dev->setup_out_error = (req->status != 0);
 881                 if (!dev->setup_out_error)
 882                         free = 0;
 883                 dev->setup_out_ready = 1;
 884                 ep0_readable (dev);
 885         }
 886
 887         /* clean up as appropriate */
 888         if (free && req->buf != &dev->rbuf)
 889                 clean_req (ep, req);
 890         req->complete = epio_complete;
 891         spin_unlock_irqrestore(&dev->lock, flags);
 892 }
 893
 894 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 895 {
 896         struct dev_data *dev = ep->driver_data;
 897
 898         if (dev->setup_out_ready) {
 899                 DBG (dev, "ep0 request busy!\n");
 900                 return -EBUSY;
 901         }
 902         if (len > sizeof (dev->rbuf))
 903                 req->buf = kmalloc(len, GFP_ATOMIC);
 904         if (req->buf == NULL) {
 905                 req->buf = dev->rbuf;
 906                 return -ENOMEM;
 907         }
 908         req->complete = ep0_complete;
 909         req->length = len;
 910         req->zero = 0;
 911         return 0;
 912 }
 913
 914 static ssize_t
 915 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 916 {
 917         struct dev_data                 *dev = fd->private_data;
 918         ssize_t                         retval;
 919         enum ep0_state                  state;
 920
 921         spin_lock_irq (&dev->lock);
 922         if (dev->state <= STATE_DEV_OPENED) {
 923                 retval = -EINVAL;
 924                 goto done;
 925         }
 926
 927         /* report fd mode change before acting on it */
 928         if (dev->setup_abort) {
 929                 dev->setup_abort = 0;
 930                 retval = -EIDRM;
 931                 goto done;
 932         }
 933
 934         /* control DATA stage */
 935         if ((state = dev->state) == STATE_DEV_SETUP) {
 936
 937                 if (dev->setup_in) {            /* stall IN */
 938                         VDEBUG(dev, "ep0in stall\n");
 939                         (void) usb_ep_set_halt (dev->gadget->ep0);
 940                         retval = -EL2HLT;
 941                         dev->state = STATE_DEV_CONNECTED;
 942
 943                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
 944                         struct usb_ep           *ep = dev->gadget->ep0;
 945                         struct usb_request      *req = dev->req;
 946
 947                         if ((retval = setup_req (ep, req, 0)) == 0) {
 948                                 ++dev->udc_usage;
 949                                 spin_unlock_irq (&dev->lock);
 950                                 retval = usb_ep_queue (ep, req, GFP_KERNEL);
 951                                 spin_lock_irq (&dev->lock);
 952                                 --dev->udc_usage;
 953                         }
 954                         dev->state = STATE_DEV_CONNECTED;
 955
 956                         /* assume that was SET_CONFIGURATION */
 957                         if (dev->current_config) {
 958                                 unsigned power;
 959
 960                                 if (gadget_is_dualspeed(dev->gadget)
 961                                                 && (dev->gadget->speed
 962                                                         == USB_SPEED_HIGH))
 963                                         power = dev->hs_config->bMaxPower;
 964                                 else
 965                                         power = dev->config->bMaxPower;
 966                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
 967                         }
 968
 969                 } else {                        /* collect OUT data */
 970                         if ((fd->f_flags & O_NONBLOCK) != 0
 971                                         && !dev->setup_out_ready) {
 972                                 retval = -EAGAIN;
 973                                 goto done;
 974                         }
 975                         spin_unlock_irq (&dev->lock);
 976                         retval = wait_event_interruptible (dev->wait,
 977                                         dev->setup_out_ready != 0);
 978
 979                         /* FIXME state could change from under us */
 980                         spin_lock_irq (&dev->lock);
 981                         if (retval)
 982                                 goto done;
 983
 984                         if (dev->state != STATE_DEV_SETUP) {
 985                                 retval = -ECANCELED;
 986                                 goto done;
 987                         }
 988                         dev->state = STATE_DEV_CONNECTED;
 989
 990                         if (dev->setup_out_error)
 991                                 retval = -EIO;
 992                         else {
 993                                 len = min (len, (size_t)dev->req->actual);
 994                                 ++dev->udc_usage;
 995                                 spin_unlock_irq(&dev->lock);
 996                                 if (copy_to_user (buf, dev->req->buf, len))
 997                                         retval = -EFAULT;
 998                                 else
 999                                         retval = len;
1000                                 spin_lock_irq(&dev->lock);
1001                                 --dev->udc_usage;
1002                                 clean_req (dev->gadget->ep0, dev->req);
1003                                 /* NOTE userspace can't yet choose to stall */
1004                         }
1005                 }
1006                 goto done;
1007         }
1008
1009         /* else normal: return event data */
1010         if (len < sizeof dev->event [0]) {
1011                 retval = -EINVAL;
1012                 goto done;
1013         }
1014         len -= len % sizeof (struct usb_gadgetfs_event);
1015         dev->usermode_setup = 1;
1016
1017 scan:
1018         /* return queued events right away */
1019         if (dev->ev_next != 0) {
1020                 unsigned                i, n;
1021
1022                 n = len / sizeof (struct usb_gadgetfs_event);
1023                 if (dev->ev_next < n)
1024                         n = dev->ev_next;
1025
1026                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1027                 for (i = 0; i < n; i++) {
1028                         if (dev->event [i].type == GADGETFS_SETUP) {
1029                                 dev->state = STATE_DEV_SETUP;
1030                                 n = i + 1;
1031                                 break;
1032                         }
1033                 }
1034                 spin_unlock_irq (&dev->lock);
1035                 len = n * sizeof (struct usb_gadgetfs_event);
1036                 if (copy_to_user (buf, &dev->event, len))
1037                         retval = -EFAULT;
1038                 else
1039                         retval = len;
1040                 if (len > 0) {
1041                         /* NOTE this doesn't guard against broken drivers;
1042                          * concurrent ep0 readers may lose events.
1043                          */
1044                         spin_lock_irq (&dev->lock);
1045                         if (dev->ev_next > n) {
1046                                 memmove(&dev->event[0], &dev->event[n],
1047                                         sizeof (struct usb_gadgetfs_event)
1048                                                 * (dev->ev_next - n));
1049                         }
1050                         dev->ev_next -= n;
1051                         spin_unlock_irq (&dev->lock);
1052                 }
1053                 return retval;
1054         }
1055         if (fd->f_flags & O_NONBLOCK) {
1056                 retval = -EAGAIN;
1057                 goto done;
1058         }
1059
1060         switch (state) {
1061         default:
1062                 DBG (dev, "fail %s, state %d\n", __func__, state);
1063                 retval = -ESRCH;
1064                 break;
1065         case STATE_DEV_UNCONNECTED:
1066         case STATE_DEV_CONNECTED:
1067                 spin_unlock_irq (&dev->lock);
1068                 DBG (dev, "%s wait\n", __func__);
1069
1070                 /* wait for events */
1071                 retval = wait_event_interruptible (dev->wait,
1072                                 dev->ev_next != 0);
1073                 if (retval < 0)
1074                         return retval;
1075                 spin_lock_irq (&dev->lock);
1076                 goto scan;
1077         }
1078
1079 done:
1080         spin_unlock_irq (&dev->lock);
1081         return retval;
1082 }
1083
1084 static struct usb_gadgetfs_event *
1085 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1086 {
1087         struct usb_gadgetfs_event       *event;
1088         unsigned                        i;
1089
1090         switch (type) {
1091         /* these events purge the queue */
1092         case GADGETFS_DISCONNECT:
1093                 if (dev->state == STATE_DEV_SETUP)
1094                         dev->setup_abort = 1;
1095                 fallthrough;
1096         case GADGETFS_CONNECT:
1097                 dev->ev_next = 0;
1098                 break;
1099         case GADGETFS_SETUP:            /* previous request timed out */
1100         case GADGETFS_SUSPEND:          /* same effect */
1101                 /* these events can't be repeated */
1102                 for (i = 0; i != dev->ev_next; i++) {
1103                         if (dev->event [i].type != type)
1104                                 continue;
1105                         DBG(dev, "discard old event[%d] %d\n", i, type);
1106                         dev->ev_next--;
1107                         if (i == dev->ev_next)
1108                                 break;
1109                         /* indices start at zero, for simplicity */
1110                         memmove (&dev->event [i], &dev->event [i + 1],
1111                                 sizeof (struct usb_gadgetfs_event)
1112                                         * (dev->ev_next - i));
1113                 }
1114                 break;
1115         default:
1116                 BUG ();
1117         }
1118         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1119         event = &dev->event [dev->ev_next++];
1120         BUG_ON (dev->ev_next > N_EVENT);
1121         memset (event, 0, sizeof *event);
1122         event->type = type;
1123         return event;
1124 }
1125
1126 static ssize_t
1127 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1128 {
1129         struct dev_data         *dev = fd->private_data;
1130         ssize_t                 retval = -ESRCH;
1131
1132         /* report fd mode change before acting on it */
1133         if (dev->setup_abort) {
1134                 dev->setup_abort = 0;
1135                 retval = -EIDRM;
1136
1137         /* data and/or status stage for control request */
1138         } else if (dev->state == STATE_DEV_SETUP) {
1139
1140                 len = min_t(size_t, len, dev->setup_wLength);
1141                 if (dev->setup_in) {
1142                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1143                         if (retval == 0) {
1144                                 dev->state = STATE_DEV_CONNECTED;
1145                                 ++dev->udc_usage;
1146                                 spin_unlock_irq (&dev->lock);
1147                                 if (copy_from_user (dev->req->buf, buf, len))
1148                                         retval = -EFAULT;
1149                                 else {
1150                                         if (len < dev->setup_wLength)
1151                                                 dev->req->zero = 1;
1152                                         retval = usb_ep_queue (
1153                                                 dev->gadget->ep0, dev->req,
1154                                                 GFP_KERNEL);
1155                                 }
1156                                 spin_lock_irq(&dev->lock);
1157                                 --dev->udc_usage;
1158                                 if (retval < 0) {
1159                                         clean_req (dev->gadget->ep0, dev->req);
1160                                 } else
1161                                         retval = len;
1162
1163                                 return retval;
1164                         }
1165
1166                 /* can stall some OUT transfers */
1167                 } else if (dev->setup_can_stall) {
1168                         VDEBUG(dev, "ep0out stall\n");
1169                         (void) usb_ep_set_halt (dev->gadget->ep0);
1170                         retval = -EL2HLT;
1171                         dev->state = STATE_DEV_CONNECTED;
1172                 } else {
1173                         DBG(dev, "bogus ep0out stall!\n");
1174                 }
1175         } else
1176                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1177
1178         return retval;
1179 }
1180
1181 static int
1182 ep0_fasync (int f, struct file *fd, int on)
1183 {
1184         struct dev_data         *dev = fd->private_data;
1185         // caller must F_SETOWN before signal delivery happens
1186         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1187         return fasync_helper (f, fd, on, &dev->fasync);
1188 }
1189
1190 static struct usb_gadget_driver gadgetfs_driver;
1191
1192 static int
1193 dev_release (struct inode *inode, struct file *fd)
1194 {
1195         struct dev_data         *dev = fd->private_data;
1196
1197         /* closing ep0 === shutdown all */
1198
1199         if (dev->gadget_registered) {
1200                 usb_gadget_unregister_driver (&gadgetfs_driver);
1201                 dev->gadget_registered = false;
1202         }
1203
1204         /* at this point "good" hardware has disconnected the
1205          * device from USB; the host won't see it any more.
1206          * alternatively, all host requests will time out.
1207          */
1208
1209         kfree (dev->buf);
1210         dev->buf = NULL;
1211
1212         /* other endpoints were all decoupled from this device */
1213         spin_lock_irq(&dev->lock);
1214         dev->state = STATE_DEV_DISABLED;
1215         spin_unlock_irq(&dev->lock);
1216
1217         put_dev (dev);
1218         return 0;
1219 }
1220
1221 static __poll_t
1222 ep0_poll (struct file *fd, poll_table *wait)
1223 {
1224         struct dev_data         *dev = fd->private_data;
1225         __poll_t                mask = 0;
1226
1227         if (dev->state <= STATE_DEV_OPENED)
1228                 return DEFAULT_POLLMASK;
1229
1230         poll_wait(fd, &dev->wait, wait);
1231
1232         spin_lock_irq(&dev->lock);
1233
1234         /* report fd mode change before acting on it */
1235         if (dev->setup_abort) {
1236                 dev->setup_abort = 0;
1237                 mask = EPOLLHUP;
1238                 goto out;
1239         }
1240
1241         if (dev->state == STATE_DEV_SETUP) {
1242                 if (dev->setup_in || dev->setup_can_stall)
1243                         mask = EPOLLOUT;
1244         } else {
1245                 if (dev->ev_next != 0)
1246                         mask = EPOLLIN;
1247         }
1248 out:
1249         spin_unlock_irq(&dev->lock);
1250         return mask;
1251 }
1252
1253 static long gadget_dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1254 {
1255         struct dev_data         *dev = fd->private_data;
1256         struct usb_gadget       *gadget = dev->gadget;
1257         long ret = -ENOTTY;
1258
1259         spin_lock_irq(&dev->lock);
1260         if (dev->state == STATE_DEV_OPENED ||
1261                         dev->state == STATE_DEV_UNBOUND) {
1262                 /* Not bound to a UDC */
1263         } else if (gadget->ops->ioctl) {
1264                 ++dev->udc_usage;
1265                 spin_unlock_irq(&dev->lock);
1266
1267                 ret = gadget->ops->ioctl (gadget, code, value);
1268
1269                 spin_lock_irq(&dev->lock);
1270                 --dev->udc_usage;
1271         }
1272         spin_unlock_irq(&dev->lock);
1273
1274         return ret;
1275 }
1276
1277 /*----------------------------------------------------------------------*/
1278
1279 /* The in-kernel gadget driver handles most ep0 issues, in particular
1280  * enumerating the single configuration (as provided from user space).
1281  *
1282  * Unrecognized ep0 requests may be handled in user space.
1283  */
1284
1285 static void make_qualifier (struct dev_data *dev)
1286 {
1287         struct usb_qualifier_descriptor         qual;
1288         struct usb_device_descriptor            *desc;
1289
1290         qual.bLength = sizeof qual;
1291         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1292         qual.bcdUSB = cpu_to_le16 (0x0200);
1293
1294         desc = dev->dev;
1295         qual.bDeviceClass = desc->bDeviceClass;
1296         qual.bDeviceSubClass = desc->bDeviceSubClass;
1297         qual.bDeviceProtocol = desc->bDeviceProtocol;
1298
1299         /* assumes ep0 uses the same value for both speeds ... */
1300         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1301
1302         qual.bNumConfigurations = 1;
1303         qual.bRESERVED = 0;
1304
1305         memcpy (dev->rbuf, &qual, sizeof qual);
1306 }
1307
1308 static int
1309 config_buf (struct dev_data *dev, u8 type, unsigned index)
1310 {
1311         int             len;
1312         int             hs = 0;
1313
1314         /* only one configuration */
1315         if (index > 0)
1316                 return -EINVAL;
1317
1318         if (gadget_is_dualspeed(dev->gadget)) {
1319                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1320                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1321                         hs = !hs;
1322         }
1323         if (hs) {
1324                 dev->req->buf = dev->hs_config;
1325                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1326         } else {
1327                 dev->req->buf = dev->config;
1328                 len = le16_to_cpu(dev->config->wTotalLength);
1329         }
1330         ((u8 *)dev->req->buf) [1] = type;
1331         return len;
1332 }
1333
1334 static int
1335 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1336 {
1337         struct dev_data                 *dev = get_gadget_data (gadget);
1338         struct usb_request              *req = dev->req;
1339         int                             value = -EOPNOTSUPP;
1340         struct usb_gadgetfs_event       *event;
1341         u16                             w_value = le16_to_cpu(ctrl->wValue);
1342         u16                             w_length = le16_to_cpu(ctrl->wLength);
1343
1344         if (w_length > RBUF_SIZE) {
1345                 if (ctrl->bRequestType & USB_DIR_IN) {
1346                         /* Cast away the const, we are going to overwrite on purpose. */
1347                         __le16 *temp = (__le16 *)&ctrl->wLength;
1348
1349                         *temp = cpu_to_le16(RBUF_SIZE);
1350                         w_length = RBUF_SIZE;
1351                 } else {
1352                         return value;
1353                 }
1354         }
1355
1356         spin_lock (&dev->lock);
1357         dev->setup_abort = 0;
1358         if (dev->state == STATE_DEV_UNCONNECTED) {
1359                 if (gadget_is_dualspeed(gadget)
1360                                 && gadget->speed == USB_SPEED_HIGH
1361                                 && dev->hs_config == NULL) {
1362                         spin_unlock(&dev->lock);
1363                         ERROR (dev, "no high speed config??\n");
1364                         return -EINVAL;
1365                 }
1366
1367                 dev->state = STATE_DEV_CONNECTED;
1368
1369                 INFO (dev, "connected\n");
1370                 event = next_event (dev, GADGETFS_CONNECT);
1371                 event->u.speed = gadget->speed;
1372                 ep0_readable (dev);
1373
1374         /* host may have given up waiting for response.  we can miss control
1375          * requests handled lower down (device/endpoint status and features);
1376          * then ep0_{read,write} will report the wrong status. controller
1377          * driver will have aborted pending i/o.
1378          */
1379         } else if (dev->state == STATE_DEV_SETUP)
1380                 dev->setup_abort = 1;
1381
1382         req->buf = dev->rbuf;
1383         req->context = NULL;
1384         switch (ctrl->bRequest) {
1385
1386         case USB_REQ_GET_DESCRIPTOR:
1387                 if (ctrl->bRequestType != USB_DIR_IN)
1388                         goto unrecognized;
1389                 switch (w_value >> 8) {
1390
1391                 case USB_DT_DEVICE:
1392                         value = min (w_length, (u16) sizeof *dev->dev);
1393                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1394                         req->buf = dev->dev;
1395                         break;
1396                 case USB_DT_DEVICE_QUALIFIER:
1397                         if (!dev->hs_config)
1398                                 break;
1399                         value = min (w_length, (u16)
1400                                 sizeof (struct usb_qualifier_descriptor));
1401                         make_qualifier (dev);
1402                         break;
1403                 case USB_DT_OTHER_SPEED_CONFIG:
1404                 case USB_DT_CONFIG:
1405                         value = config_buf (dev,
1406                                         w_value >> 8,
1407                                         w_value & 0xff);
1408                         if (value >= 0)
1409                                 value = min (w_length, (u16) value);
1410                         break;
1411                 case USB_DT_STRING:
1412                         goto unrecognized;
1413
1414                 default:                // all others are errors
1415                         break;
1416                 }
1417                 break;
1418
1419         /* currently one config, two speeds */
1420         case USB_REQ_SET_CONFIGURATION:
1421                 if (ctrl->bRequestType != 0)
1422                         goto unrecognized;
1423                 if (0 == (u8) w_value) {
1424                         value = 0;
1425                         dev->current_config = 0;
1426                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1427                         // user mode expected to disable endpoints
1428                 } else {
1429                         u8      config, power;
1430
1431                         if (gadget_is_dualspeed(gadget)
1432                                         && gadget->speed == USB_SPEED_HIGH) {
1433                                 config = dev->hs_config->bConfigurationValue;
1434                                 power = dev->hs_config->bMaxPower;
1435                         } else {
1436                                 config = dev->config->bConfigurationValue;
1437                                 power = dev->config->bMaxPower;
1438                         }
1439
1440                         if (config == (u8) w_value) {
1441                                 value = 0;
1442                                 dev->current_config = config;
1443                                 usb_gadget_vbus_draw(gadget, 2 * power);
1444                         }
1445                 }
1446
1447                 /* report SET_CONFIGURATION like any other control request,
1448                  * except that usermode may not stall this.  the next
1449                  * request mustn't be allowed start until this finishes:
1450                  * endpoints and threads set up, etc.
1451                  *
1452                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1453                  * has bad/racey automagic that prevents synchronizing here.
1454                  * even kernel mode drivers often miss them.
1455                  */
1456                 if (value == 0) {
1457                         INFO (dev, "configuration #%d\n", dev->current_config);
1458                         usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1459                         if (dev->usermode_setup) {
1460                                 dev->setup_can_stall = 0;
1461                                 goto delegate;
1462                         }
1463                 }
1464                 break;
1465
1466 #ifndef CONFIG_USB_PXA25X
1467         /* PXA automagically handles this request too */
1468         case USB_REQ_GET_CONFIGURATION:
1469                 if (ctrl->bRequestType != 0x80)
1470                         goto unrecognized;
1471                 *(u8 *)req->buf = dev->current_config;
1472                 value = min (w_length, (u16) 1);
1473                 break;
1474 #endif
1475
1476         default:
1477 unrecognized:
1478                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1479                         dev->usermode_setup ? "delegate" : "fail",
1480                         ctrl->bRequestType, ctrl->bRequest,
1481                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1482
1483                 /* if there's an ep0 reader, don't stall */
1484                 if (dev->usermode_setup) {
1485                         dev->setup_can_stall = 1;
1486 delegate:
1487                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1488                                                 ? 1 : 0;
1489                         dev->setup_wLength = w_length;
1490                         dev->setup_out_ready = 0;
1491                         dev->setup_out_error = 0;
1492
1493                         /* read DATA stage for OUT right away */
1494                         if (unlikely (!dev->setup_in && w_length)) {
1495                                 value = setup_req (gadget->ep0, dev->req,
1496                                                         w_length);
1497                                 if (value < 0)
1498                                         break;
1499
1500                                 ++dev->udc_usage;
1501                                 spin_unlock (&dev->lock);
1502                                 value = usb_ep_queue (gadget->ep0, dev->req,
1503                                                         GFP_KERNEL);
1504                                 spin_lock (&dev->lock);
1505                                 --dev->udc_usage;
1506                                 if (value < 0) {
1507                                         clean_req (gadget->ep0, dev->req);
1508                                         break;
1509                                 }
1510
1511                                 /* we can't currently stall these */
1512                                 dev->setup_can_stall = 0;
1513                         }
1514
1515                         /* state changes when reader collects event */
1516                         event = next_event (dev, GADGETFS_SETUP);
1517                         event->u.setup = *ctrl;
1518                         ep0_readable (dev);
1519                         spin_unlock (&dev->lock);
1520                         /*
1521                          * Return USB_GADGET_DELAYED_STATUS as a workaround to
1522                          * stop some UDC drivers (e.g. dwc3) from automatically
1523                          * proceeding with the status stage for 0-length
1524                          * transfers.
1525                          * Should be removed once all UDC drivers are fixed to
1526                          * always delay the status stage until a response is
1527                          * queued to EP0.
1528                          */
1529                         return w_length == 0 ? USB_GADGET_DELAYED_STATUS : 0;
1530                 }
1531         }
1532
1533         /* proceed with data transfer and status phases? */
1534         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1535                 req->length = value;
1536                 req->zero = value < w_length;
1537
1538                 ++dev->udc_usage;
1539                 spin_unlock (&dev->lock);
1540                 value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1541                 spin_lock(&dev->lock);
1542                 --dev->udc_usage;
1543                 spin_unlock(&dev->lock);
1544                 if (value < 0) {
1545                         DBG (dev, "ep_queue --> %d\n", value);
1546                         req->status = 0;
1547                 }
1548                 return value;
1549         }
1550
1551         /* device stalls when value < 0 */
1552         spin_unlock (&dev->lock);
1553         return value;
1554 }
1555
1556 static void destroy_ep_files (struct dev_data *dev)
1557 {
1558         DBG (dev, "%s %d\n", __func__, dev->state);
1559
1560         /* dev->state must prevent interference */
1561         spin_lock_irq (&dev->lock);
1562         while (!list_empty(&dev->epfiles)) {
1563                 struct ep_data  *ep;
1564                 struct inode    *parent;
1565                 struct dentry   *dentry;
1566
1567                 /* break link to FS */
1568                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1569                 list_del_init (&ep->epfiles);
1570                 spin_unlock_irq (&dev->lock);
1571
1572                 dentry = ep->dentry;
1573                 ep->dentry = NULL;
1574                 parent = d_inode(dentry->d_parent);
1575
1576                 /* break link to controller */
1577                 mutex_lock(&ep->lock);
1578                 if (ep->state == STATE_EP_ENABLED)
1579                         (void) usb_ep_disable (ep->ep);
1580                 ep->state = STATE_EP_UNBOUND;
1581                 usb_ep_free_request (ep->ep, ep->req);
1582                 ep->ep = NULL;
1583                 mutex_unlock(&ep->lock);
1584
1585                 wake_up (&ep->wait);
1586                 put_ep (ep);
1587
1588                 /* break link to dcache */
1589                 inode_lock(parent);
1590                 d_delete (dentry);
1591                 dput (dentry);
1592                 inode_unlock(parent);
1593
1594                 spin_lock_irq (&dev->lock);
1595         }
1596         spin_unlock_irq (&dev->lock);
1597 }
1598
1599
1600 static struct dentry *
1601 gadgetfs_create_file (struct super_block *sb, char const *name,
1602                 void *data, const struct file_operations *fops);
1603
1604 static int activate_ep_files (struct dev_data *dev)
1605 {
1606         struct usb_ep   *ep;
1607         struct ep_data  *data;
1608
1609         gadget_for_each_ep (ep, dev->gadget) {
1610
1611                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1612                 if (!data)
1613                         goto enomem0;
1614                 data->state = STATE_EP_DISABLED;
1615                 mutex_init(&data->lock);
1616                 init_waitqueue_head (&data->wait);
1617
1618                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1619                 refcount_set (&data->count, 1);
1620                 data->dev = dev;
1621                 get_dev (dev);
1622
1623                 data->ep = ep;
1624                 ep->driver_data = data;
1625
1626                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1627                 if (!data->req)
1628                         goto enomem1;
1629
1630                 data->dentry = gadgetfs_create_file (dev->sb, data->name,
1631                                 data, &ep_io_operations);
1632                 if (!data->dentry)
1633                         goto enomem2;
1634                 list_add_tail (&data->epfiles, &dev->epfiles);
1635         }
1636         return 0;
1637
1638 enomem2:
1639         usb_ep_free_request (ep, data->req);
1640 enomem1:
1641         put_dev (dev);
1642         kfree (data);
1643 enomem0:
1644         DBG (dev, "%s enomem\n", __func__);
1645         destroy_ep_files (dev);
1646         return -ENOMEM;
1647 }
1648
1649 static void
1650 gadgetfs_unbind (struct usb_gadget *gadget)
1651 {
1652         struct dev_data         *dev = get_gadget_data (gadget);
1653
1654         DBG (dev, "%s\n", __func__);
1655
1656         spin_lock_irq (&dev->lock);
1657         dev->state = STATE_DEV_UNBOUND;
1658         while (dev->udc_usage > 0) {
1659                 spin_unlock_irq(&dev->lock);
1660                 usleep_range(1000, 2000);
1661                 spin_lock_irq(&dev->lock);
1662         }
1663         spin_unlock_irq (&dev->lock);
1664
1665         destroy_ep_files (dev);
1666         gadget->ep0->driver_data = NULL;
1667         set_gadget_data (gadget, NULL);
1668
1669         /* we've already been disconnected ... no i/o is active */
1670         if (dev->req)
1671                 usb_ep_free_request (gadget->ep0, dev->req);
1672         DBG (dev, "%s done\n", __func__);
1673         put_dev (dev);
1674 }
1675
1676 static struct dev_data          *the_device;
1677
1678 static int gadgetfs_bind(struct usb_gadget *gadget,
1679                 struct usb_gadget_driver *driver)
1680 {
1681         struct dev_data         *dev = the_device;
1682
1683         if (!dev)
1684                 return -ESRCH;
1685         if (0 != strcmp (CHIP, gadget->name)) {
1686                 pr_err("%s expected %s controller not %s\n",
1687                         shortname, CHIP, gadget->name);
1688                 return -ENODEV;
1689         }
1690
1691         set_gadget_data (gadget, dev);
1692         dev->gadget = gadget;
1693         gadget->ep0->driver_data = dev;
1694
1695         /* preallocate control response and buffer */
1696         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1697         if (!dev->req)
1698                 goto enomem;
1699         dev->req->context = NULL;
1700         dev->req->complete = epio_complete;
1701
1702         if (activate_ep_files (dev) < 0)
1703                 goto enomem;
1704
1705         INFO (dev, "bound to %s driver\n", gadget->name);
1706         spin_lock_irq(&dev->lock);
1707         dev->state = STATE_DEV_UNCONNECTED;
1708         spin_unlock_irq(&dev->lock);
1709         get_dev (dev);
1710         return 0;
1711
1712 enomem:
1713         gadgetfs_unbind (gadget);
1714         return -ENOMEM;
1715 }
1716
1717 static void
1718 gadgetfs_disconnect (struct usb_gadget *gadget)
1719 {
1720         struct dev_data         *dev = get_gadget_data (gadget);
1721         unsigned long           flags;
1722
1723         spin_lock_irqsave (&dev->lock, flags);
1724         if (dev->state == STATE_DEV_UNCONNECTED)
1725                 goto exit;
1726         dev->state = STATE_DEV_UNCONNECTED;
1727
1728         INFO (dev, "disconnected\n");
1729         next_event (dev, GADGETFS_DISCONNECT);
1730         ep0_readable (dev);
1731 exit:
1732         spin_unlock_irqrestore (&dev->lock, flags);
1733 }
1734
1735 static void
1736 gadgetfs_suspend (struct usb_gadget *gadget)
1737 {
1738         struct dev_data         *dev = get_gadget_data (gadget);
1739         unsigned long           flags;
1740
1741         INFO (dev, "suspended from state %d\n", dev->state);
1742         spin_lock_irqsave(&dev->lock, flags);
1743         switch (dev->state) {
1744         case STATE_DEV_SETUP:           // VERY odd... host died??
1745         case STATE_DEV_CONNECTED:
1746         case STATE_DEV_UNCONNECTED:
1747                 next_event (dev, GADGETFS_SUSPEND);
1748                 ep0_readable (dev);
1749                 fallthrough;
1750         default:
1751                 break;
1752         }
1753         spin_unlock_irqrestore(&dev->lock, flags);
1754 }
1755
1756 static struct usb_gadget_driver gadgetfs_driver = {
1757         .function       = (char *) driver_desc,
1758         .bind           = gadgetfs_bind,
1759         .unbind         = gadgetfs_unbind,
1760         .setup          = gadgetfs_setup,
1761         .reset          = gadgetfs_disconnect,
1762         .disconnect     = gadgetfs_disconnect,
1763         .suspend        = gadgetfs_suspend,
1764
1765         .driver = {
1766                 .name           = shortname,
1767         },
1768 };
1769
1770 /*----------------------------------------------------------------------*/
1771 /* DEVICE INITIALIZATION
1772  *
1773  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1774  *     status = write (fd, descriptors, sizeof descriptors)
1775  *
1776  * That write establishes the device configuration, so the kernel can
1777  * bind to the controller ... guaranteeing it can handle enumeration
1778  * at all necessary speeds.  Descriptor order is:
1779  *
1780  * . message tag (u32, host order) ... for now, must be zero; it
1781  *      would change to support features like multi-config devices
1782  * . full/low speed config ... all wTotalLength bytes (with interface,
1783  *      class, altsetting, endpoint, and other descriptors)
1784  * . high speed config ... all descriptors, for high speed operation;
1785  *      this one's optional except for high-speed hardware
1786  * . device descriptor
1787  *
1788  * Endpoints are not yet enabled. Drivers must wait until device
1789  * configuration and interface altsetting changes create
1790  * the need to configure (or unconfigure) them.
1791  *
1792  * After initialization, the device stays active for as long as that
1793  * $CHIP file is open.  Events must then be read from that descriptor,
1794  * such as configuration notifications.
1795  */
1796
1797 static int is_valid_config(struct usb_config_descriptor *config,
1798                 unsigned int total)
1799 {
1800         return config->bDescriptorType == USB_DT_CONFIG
1801                 && config->bLength == USB_DT_CONFIG_SIZE
1802                 && total >= USB_DT_CONFIG_SIZE
1803                 && config->bConfigurationValue != 0
1804                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1805                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1806         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1807         /* FIXME check lengths: walk to end */
1808 }
1809
1810 static ssize_t
1811 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1812 {
1813         struct dev_data         *dev = fd->private_data;
1814         ssize_t                 value, length = len;
1815         unsigned                total;
1816         u32                     tag;
1817         char                    *kbuf;
1818
1819         spin_lock_irq(&dev->lock);
1820         if (dev->state > STATE_DEV_OPENED) {
1821                 value = ep0_write(fd, buf, len, ptr);
1822                 spin_unlock_irq(&dev->lock);
1823                 return value;
1824         }
1825         spin_unlock_irq(&dev->lock);
1826
1827         if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1828             (len > PAGE_SIZE * 4))
1829                 return -EINVAL;
1830
1831         /* we might need to change message format someday */
1832         if (copy_from_user (&tag, buf, 4))
1833                 return -EFAULT;
1834         if (tag != 0)
1835                 return -EINVAL;
1836         buf += 4;
1837         length -= 4;
1838
1839         kbuf = memdup_user(buf, length);
1840         if (IS_ERR(kbuf))
1841                 return PTR_ERR(kbuf);
1842
1843         spin_lock_irq (&dev->lock);
1844         value = -EINVAL;
1845         if (dev->buf) {
1846                 spin_unlock_irq(&dev->lock);
1847                 kfree(kbuf);
1848                 return value;
1849         }
1850         dev->buf = kbuf;
1851
1852         /* full or low speed config */
1853         dev->config = (void *) kbuf;
1854         total = le16_to_cpu(dev->config->wTotalLength);
1855         if (!is_valid_config(dev->config, total) ||
1856                         total > length - USB_DT_DEVICE_SIZE)
1857                 goto fail;
1858         kbuf += total;
1859         length -= total;
1860
1861         /* optional high speed config */
1862         if (kbuf [1] == USB_DT_CONFIG) {
1863                 dev->hs_config = (void *) kbuf;
1864                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1865                 if (!is_valid_config(dev->hs_config, total) ||
1866                                 total > length - USB_DT_DEVICE_SIZE)
1867                         goto fail;
1868                 kbuf += total;
1869                 length -= total;
1870         } else {
1871                 dev->hs_config = NULL;
1872         }
1873
1874         /* could support multiple configs, using another encoding! */
1875
1876         /* device descriptor (tweaked for paranoia) */
1877         if (length != USB_DT_DEVICE_SIZE)
1878                 goto fail;
1879         dev->dev = (void *)kbuf;
1880         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1881                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1882                         || dev->dev->bNumConfigurations != 1)
1883                 goto fail;
1884         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1885
1886         /* triggers gadgetfs_bind(); then we can enumerate. */
1887         spin_unlock_irq (&dev->lock);
1888         if (dev->hs_config)
1889                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1890         else
1891                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1892
1893         value = usb_gadget_register_driver(&gadgetfs_driver);
1894         if (value != 0) {
1895                 spin_lock_irq(&dev->lock);
1896                 goto fail;
1897         } else {
1898                 /* at this point "good" hardware has for the first time
1899                  * let the USB the host see us.  alternatively, if users
1900                  * unplug/replug that will clear all the error state.
1901                  *
1902                  * note:  everything running before here was guaranteed
1903                  * to choke driver model style diagnostics.  from here
1904                  * on, they can work ... except in cleanup paths that
1905                  * kick in after the ep0 descriptor is closed.
1906                  */
1907                 value = len;
1908                 dev->gadget_registered = true;
1909         }
1910         return value;
1911
1912 fail:
1913         dev->config = NULL;
1914         dev->hs_config = NULL;
1915         dev->dev = NULL;
1916         spin_unlock_irq (&dev->lock);
1917         pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev);
1918         kfree (dev->buf);
1919         dev->buf = NULL;
1920         return value;
1921 }
1922
1923 static int
1924 gadget_dev_open (struct inode *inode, struct file *fd)
1925 {
1926         struct dev_data         *dev = inode->i_private;
1927         int                     value = -EBUSY;
1928
1929         spin_lock_irq(&dev->lock);
1930         if (dev->state == STATE_DEV_DISABLED) {
1931                 dev->ev_next = 0;
1932                 dev->state = STATE_DEV_OPENED;
1933                 fd->private_data = dev;
1934                 get_dev (dev);
1935                 value = 0;
1936         }
1937         spin_unlock_irq(&dev->lock);
1938         return value;
1939 }
1940
1941 static const struct file_operations ep0_operations = {
1942         .llseek =       no_llseek,
1943
1944         .open =         gadget_dev_open,
1945         .read =         ep0_read,
1946         .write =        dev_config,
1947         .fasync =       ep0_fasync,
1948         .poll =         ep0_poll,
1949         .unlocked_ioctl = gadget_dev_ioctl,
1950         .release =      dev_release,
1951 };
1952
1953 /*----------------------------------------------------------------------*/
1954
1955 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1956  *
1957  * Mounting the filesystem creates a controller file, used first for
1958  * device configuration then later for event monitoring.
1959  */
1960
1961
1962 /* FIXME PAM etc could set this security policy without mount options
1963  * if epfiles inherited ownership and permissons from ep0 ...
1964  */
1965
1966 static unsigned default_uid;
1967 static unsigned default_gid;
1968 static unsigned default_perm = S_IRUSR | S_IWUSR;
1969
1970 module_param (default_uid, uint, 0644);
1971 module_param (default_gid, uint, 0644);
1972 module_param (default_perm, uint, 0644);
1973
1974
1975 static struct inode *
1976 gadgetfs_make_inode (struct super_block *sb,
1977                 void *data, const struct file_operations *fops,
1978                 int mode)
1979 {
1980         struct inode *inode = new_inode (sb);
1981
1982         if (inode) {
1983                 inode->i_ino = get_next_ino();
1984                 inode->i_mode = mode;
1985                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
1986                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
1987                 simple_inode_init_ts(inode);
1988                 inode->i_private = data;
1989                 inode->i_fop = fops;
1990         }
1991         return inode;
1992 }
1993
1994 /* creates in fs root directory, so non-renamable and non-linkable.
1995  * so inode and dentry are paired, until device reconfig.
1996  */
1997 static struct dentry *
1998 gadgetfs_create_file (struct super_block *sb, char const *name,
1999                 void *data, const struct file_operations *fops)
2000 {
2001         struct dentry   *dentry;
2002         struct inode    *inode;
2003
2004         dentry = d_alloc_name(sb->s_root, name);
2005         if (!dentry)
2006                 return NULL;
2007
2008         inode = gadgetfs_make_inode (sb, data, fops,
2009                         S_IFREG | (default_perm & S_IRWXUGO));
2010         if (!inode) {
2011                 dput(dentry);
2012                 return NULL;
2013         }
2014         d_add (dentry, inode);
2015         return dentry;
2016 }
2017
2018 static const struct super_operations gadget_fs_operations = {
2019         .statfs =       simple_statfs,
2020         .drop_inode =   generic_delete_inode,
2021 };
2022
2023 static int
2024 gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc)
2025 {
2026         struct inode    *inode;
2027         struct dev_data *dev;
2028         int             rc;
2029
2030         mutex_lock(&sb_mutex);
2031
2032         if (the_device) {
2033                 rc = -ESRCH;
2034                 goto Done;
2035         }
2036
2037         CHIP = usb_get_gadget_udc_name();
2038         if (!CHIP) {
2039                 rc = -ENODEV;
2040                 goto Done;
2041         }
2042
2043         /* superblock */
2044         sb->s_blocksize = PAGE_SIZE;
2045         sb->s_blocksize_bits = PAGE_SHIFT;
2046         sb->s_magic = GADGETFS_MAGIC;
2047         sb->s_op = &gadget_fs_operations;
2048         sb->s_time_gran = 1;
2049
2050         /* root inode */
2051         inode = gadgetfs_make_inode (sb,
2052                         NULL, &simple_dir_operations,
2053                         S_IFDIR | S_IRUGO | S_IXUGO);
2054         if (!inode)
2055                 goto Enomem;
2056         inode->i_op = &simple_dir_inode_operations;
2057         if (!(sb->s_root = d_make_root (inode)))
2058                 goto Enomem;
2059
2060         /* the ep0 file is named after the controller we expect;
2061          * user mode code can use it for sanity checks, like we do.
2062          */
2063         dev = dev_new ();
2064         if (!dev)
2065                 goto Enomem;
2066
2067         dev->sb = sb;
2068         dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2069         if (!dev->dentry) {
2070                 put_dev(dev);
2071                 goto Enomem;
2072         }
2073
2074         /* other endpoint files are available after hardware setup,
2075          * from binding to a controller.
2076          */
2077         the_device = dev;
2078         rc = 0;
2079         goto Done;
2080
2081  Enomem:
2082         kfree(CHIP);
2083         CHIP = NULL;
2084         rc = -ENOMEM;
2085
2086  Done:
2087         mutex_unlock(&sb_mutex);
2088         return rc;
2089 }
2090
2091 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2092 static int gadgetfs_get_tree(struct fs_context *fc)
2093 {
2094         return get_tree_single(fc, gadgetfs_fill_super);
2095 }
2096
2097 static const struct fs_context_operations gadgetfs_context_ops = {
2098         .get_tree       = gadgetfs_get_tree,
2099 };
2100
2101 static int gadgetfs_init_fs_context(struct fs_context *fc)
2102 {
2103         fc->ops = &gadgetfs_context_ops;
2104         return 0;
2105 }
2106
2107 static void
2108 gadgetfs_kill_sb (struct super_block *sb)
2109 {
2110         mutex_lock(&sb_mutex);
2111         kill_litter_super (sb);
2112         if (the_device) {
2113                 put_dev (the_device);
2114                 the_device = NULL;
2115         }
2116         kfree(CHIP);
2117         CHIP = NULL;
2118         mutex_unlock(&sb_mutex);
2119 }
2120
2121 /*----------------------------------------------------------------------*/
2122
2123 static struct file_system_type gadgetfs_type = {
2124         .owner          = THIS_MODULE,
2125         .name           = shortname,
2126         .init_fs_context = gadgetfs_init_fs_context,
2127         .kill_sb        = gadgetfs_kill_sb,
2128 };
2129 MODULE_ALIAS_FS("gadgetfs");
2130
2131 /*----------------------------------------------------------------------*/
2132
2133 static int __init gadgetfs_init (void)
2134 {
2135         int status;
2136
2137         status = register_filesystem (&gadgetfs_type);
2138         if (status == 0)
2139                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2140                         shortname, driver_desc);
2141         return status;
2142 }
2143 module_init (gadgetfs_init);
2144
2145 static void __exit gadgetfs_cleanup (void)
2146 {
2147         pr_debug ("unregister %s\n", shortname);
2148         unregister_filesystem (&gadgetfs_type);
2149 }
2150 module_exit (gadgetfs_cleanup);
2151