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