drivers/usb/gadget/legacy/inode.c

   1 /*
   2  * inode.c -- user mode filesystem api for usb gadget controllers
   3  *
   4  * Copyright (C) 2003-2004 David Brownell
   5  * Copyright (C) 2003 Agilent Technologies
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13
  14 /* #define VERBOSE_DEBUG */
  15
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/fs.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/uts.h>
  21 #include <linux/wait.h>
  22 #include <linux/compiler.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/sched.h>
  25 #include <linux/slab.h>
  26 #include <linux/poll.h>
  27 #include <linux/mmu_context.h>
  28 #include <linux/aio.h>
  29 #include <linux/uio.h>
  30 #include <linux/refcount.h>
  31 #include <linux/delay.h>
  32 #include <linux/device.h>
  33 #include <linux/moduleparam.h>
  34
  35 #include <linux/usb/gadgetfs.h>
  36 #include <linux/usb/gadget.h>
  37
  38
  39 /*
  40  * The gadgetfs API maps each endpoint to a file descriptor so that you
  41  * can use standard synchronous read/write calls for I/O.  There's some
  42  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  43  * drivers show how this works in practice.  You can also use AIO to
  44  * eliminate I/O gaps between requests, to help when streaming data.
  45  *
  46  * Key parts that must be USB-specific are protocols defining how the
  47  * read/write operations relate to the hardware state machines.  There
  48  * are two types of files.  One type is for the device, implementing ep0.
  49  * The other type is for each IN or OUT endpoint.  In both cases, the
  50  * user mode driver must configure the hardware before using it.
  51  *
  52  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  53  *   (by writing configuration and device descriptors).  Afterwards it
  54  *   may serve as a source of device events, used to handle all control
  55  *   requests other than basic enumeration.
  56  *
  57  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  58  *   called when each /dev/gadget/ep* file is configured (by writing
  59  *   endpoint descriptors).  Afterwards these files are used to write()
  60  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  61  *   direction" request is issued (like reading an IN endpoint).
  62  *
  63  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  64  * not possible on all hardware.  For example, precise fault handling with
  65  * respect to data left in endpoint fifos after aborted operations; or
  66  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  67  */
  68
  69 #define DRIVER_DESC     "USB Gadget filesystem"
  70 #define DRIVER_VERSION  "24 Aug 2004"
  71
  72 static const char driver_desc [] = DRIVER_DESC;
  73 static const char shortname [] = "gadgetfs";
  74
  75 MODULE_DESCRIPTION (DRIVER_DESC);
  76 MODULE_AUTHOR ("David Brownell");
  77 MODULE_LICENSE ("GPL");
  78
  79 static int ep_open(struct inode *, struct file *);
  80
  81
  82 /*----------------------------------------------------------------------*/
  83
  84 #define GADGETFS_MAGIC          0xaee71ee7
  85
  86 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  87 enum ep0_state {
  88         /* DISABLED is the initial state. */
  89         STATE_DEV_DISABLED = 0,
  90
  91         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  92          * ep0/device i/o modes and binding to the controller.  Driver
  93          * must always write descriptors to initialize the device, then
  94          * the device becomes UNCONNECTED until enumeration.
  95          */
  96         STATE_DEV_OPENED,
  97
  98         /* From then on, ep0 fd is in either of two basic modes:
  99          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
 100          * - SETUP: read/write will transfer control data and succeed;
 101          *   or if "wrong direction", performs protocol stall
 102          */
 103         STATE_DEV_UNCONNECTED,
 104         STATE_DEV_CONNECTED,
 105         STATE_DEV_SETUP,
 106
 107         /* UNBOUND means the driver closed ep0, so the device won't be
 108          * accessible again (DEV_DISABLED) until all fds are closed.
 109          */
 110         STATE_DEV_UNBOUND,
 111 };
 112
 113 /* enough for the whole queue: most events invalidate others */
 114 #define N_EVENT                 5
 115
 116 struct dev_data {
 117         spinlock_t                      lock;
 118         refcount_t                      count;
 119         int                             udc_usage;
 120         enum ep0_state                  state;          /* P: lock */
 121         struct usb_gadgetfs_event       event [N_EVENT];
 122         unsigned                        ev_next;
 123         struct fasync_struct            *fasync;
 124         u8                              current_config;
 125
 126         /* drivers reading ep0 MUST handle control requests (SETUP)
 127          * reported that way; else the host will time out.
 128          */
 129         unsigned                        usermode_setup : 1,
 130                                         setup_in : 1,
 131                                         setup_can_stall : 1,
 132                                         setup_out_ready : 1,
 133                                         setup_out_error : 1,
 134                                         setup_abort : 1,
 135                                         gadget_registered : 1;
 136         unsigned                        setup_wLength;
 137
 138         /* the rest is basically write-once */
 139         struct usb_config_descriptor    *config, *hs_config;
 140         struct usb_device_descriptor    *dev;
 141         struct usb_request              *req;
 142         struct usb_gadget               *gadget;
 143         struct list_head                epfiles;
 144         void                            *buf;
 145         wait_queue_head_t               wait;
 146         struct super_block              *sb;
 147         struct dentry                   *dentry;
 148
 149         /* except this scratch i/o buffer for ep0 */
 150         u8                              rbuf [256];
 151 };
 152
 153 static inline void get_dev (struct dev_data *data)
 154 {
 155         refcount_inc (&data->count);
 156 }
 157
 158 static void put_dev (struct dev_data *data)
 159 {
 160         if (likely (!refcount_dec_and_test (&data->count)))
 161                 return;
 162         /* needs no more cleanup */
 163         BUG_ON (waitqueue_active (&data->wait));
 164         kfree (data);
 165 }
 166
 167 static struct dev_data *dev_new (void)
 168 {
 169         struct dev_data         *dev;
 170
 171         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 172         if (!dev)
 173                 return NULL;
 174         dev->state = STATE_DEV_DISABLED;
 175         refcount_set (&dev->count, 1);
 176         spin_lock_init (&dev->lock);
 177         INIT_LIST_HEAD (&dev->epfiles);
 178         init_waitqueue_head (&dev->wait);
 179         return dev;
 180 }
 181
 182 /*----------------------------------------------------------------------*/
 183
 184 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 185 enum ep_state {
 186         STATE_EP_DISABLED = 0,
 187         STATE_EP_READY,
 188         STATE_EP_ENABLED,
 189         STATE_EP_UNBOUND,
 190 };
 191
 192 struct ep_data {
 193         struct mutex                    lock;
 194         enum ep_state                   state;
 195         refcount_t                      count;
 196         struct dev_data                 *dev;
 197         /* must hold dev->lock before accessing ep or req */
 198         struct usb_ep                   *ep;
 199         struct usb_request              *req;
 200         ssize_t                         status;
 201         char                            name [16];
 202         struct usb_endpoint_descriptor  desc, hs_desc;
 203         struct list_head                epfiles;
 204         wait_queue_head_t               wait;
 205         struct dentry                   *dentry;
 206 };
 207
 208 static inline void get_ep (struct ep_data *data)
 209 {
 210         refcount_inc (&data->count);
 211 }
 212
 213 static void put_ep (struct ep_data *data)
 214 {
 215         if (likely (!refcount_dec_and_test (&data->count)))
 216                 return;
 217         put_dev (data->dev);
 218         /* needs no more cleanup */
 219         BUG_ON (!list_empty (&data->epfiles));
 220         BUG_ON (waitqueue_active (&data->wait));
 221         kfree (data);
 222 }
 223
 224 /*----------------------------------------------------------------------*/
 225
 226 /* most "how to use the hardware" policy choices are in userspace:
 227  * mapping endpoint roles (which the driver needs) to the capabilities
 228  * which the usb controller has.  most of those capabilities are exposed
 229  * implicitly, starting with the driver name and then endpoint names.
 230  */
 231
 232 static const char *CHIP;
 233
 234 /*----------------------------------------------------------------------*/
 235
 236 /* NOTE:  don't use dev_printk calls before binding to the gadget
 237  * at the end of ep0 configuration, or after unbind.
 238  */
 239
 240 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 241 #define xprintk(d,level,fmt,args...) \
 242         printk(level "%s: " fmt , shortname , ## args)
 243
 244 #ifdef DEBUG
 245 #define DBG(dev,fmt,args...) \
 246         xprintk(dev , KERN_DEBUG , fmt , ## args)
 247 #else
 248 #define DBG(dev,fmt,args...) \
 249         do { } while (0)
 250 #endif /* DEBUG */
 251
 252 #ifdef VERBOSE_DEBUG
 253 #define VDEBUG  DBG
 254 #else
 255 #define VDEBUG(dev,fmt,args...) \
 256         do { } while (0)
 257 #endif /* DEBUG */
 258
 259 #define ERROR(dev,fmt,args...) \
 260         xprintk(dev , KERN_ERR , fmt , ## args)
 261 #define INFO(dev,fmt,args...) \
 262         xprintk(dev , KERN_INFO , fmt , ## args)
 263
 264
 265 /*----------------------------------------------------------------------*/
 266
 267 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 268  *
 269  * After opening, configure non-control endpoints.  Then use normal
 270  * stream read() and write() requests; and maybe ioctl() to get more
 271  * precise FIFO status when recovering from cancellation.
 272  */
 273
 274 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 275 {
 276         struct ep_data  *epdata = ep->driver_data;
 277
 278         if (!req->context)
 279                 return;
 280         if (req->status)
 281                 epdata->status = req->status;
 282         else
 283                 epdata->status = req->actual;
 284         complete ((struct completion *)req->context);
 285 }
 286
 287 /* tasklock endpoint, returning when it's connected.
 288  * still need dev->lock to use epdata->ep.
 289  */
 290 static int
 291 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 292 {
 293         int     val;
 294
 295         if (f_flags & O_NONBLOCK) {
 296                 if (!mutex_trylock(&epdata->lock))
 297                         goto nonblock;
 298                 if (epdata->state != STATE_EP_ENABLED &&
 299                     (!is_write || epdata->state != STATE_EP_READY)) {
 300                         mutex_unlock(&epdata->lock);
 301 nonblock:
 302                         val = -EAGAIN;
 303                 } else
 304                         val = 0;
 305                 return val;
 306         }
 307
 308         val = mutex_lock_interruptible(&epdata->lock);
 309         if (val < 0)
 310                 return val;
 311
 312         switch (epdata->state) {
 313         case STATE_EP_ENABLED:
 314                 return 0;
 315         case STATE_EP_READY:                    /* not configured yet */
 316                 if (is_write)
 317                         return 0;
 318                 // FALLTHRU
 319         case STATE_EP_UNBOUND:                  /* clean disconnect */
 320                 break;
 321         // case STATE_EP_DISABLED:              /* "can't happen" */
 322         default:                                /* error! */
 323                 pr_debug ("%s: ep %p not available, state %d\n",
 324                                 shortname, epdata, epdata->state);
 325         }
 326         mutex_unlock(&epdata->lock);
 327         return -ENODEV;
 328 }
 329
 330 static ssize_t
 331 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 332 {
 333         DECLARE_COMPLETION_ONSTACK (done);
 334         int value;
 335
 336         spin_lock_irq (&epdata->dev->lock);
 337         if (likely (epdata->ep != NULL)) {
 338                 struct usb_request      *req = epdata->req;
 339
 340                 req->context = &done;
 341                 req->complete = epio_complete;
 342                 req->buf = buf;
 343                 req->length = len;
 344                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 345         } else
 346                 value = -ENODEV;
 347         spin_unlock_irq (&epdata->dev->lock);
 348
 349         if (likely (value == 0)) {
 350                 value = wait_event_interruptible (done.wait, done.done);
 351                 if (value != 0) {
 352                         spin_lock_irq (&epdata->dev->lock);
 353                         if (likely (epdata->ep != NULL)) {
 354                                 DBG (epdata->dev, "%s i/o interrupted\n",
 355                                                 epdata->name);
 356                                 usb_ep_dequeue (epdata->ep, epdata->req);
 357                                 spin_unlock_irq (&epdata->dev->lock);
 358
 359                                 wait_event (done.wait, done.done);
 360                                 if (epdata->status == -ECONNRESET)
 361                                         epdata->status = -EINTR;
 362                         } else {
 363                                 spin_unlock_irq (&epdata->dev->lock);
 364
 365                                 DBG (epdata->dev, "endpoint gone\n");
 366                                 epdata->status = -ENODEV;
 367                         }
 368                 }
 369                 return epdata->status;
 370         }
 371         return value;
 372 }
 373
 374 static int
 375 ep_release (struct inode *inode, struct file *fd)
 376 {
 377         struct ep_data          *data = fd->private_data;
 378         int value;
 379
 380         value = mutex_lock_interruptible(&data->lock);
 381         if (value < 0)
 382                 return value;
 383
 384         /* clean up if this can be reopened */
 385         if (data->state != STATE_EP_UNBOUND) {
 386                 data->state = STATE_EP_DISABLED;
 387                 data->desc.bDescriptorType = 0;
 388                 data->hs_desc.bDescriptorType = 0;
 389                 usb_ep_disable(data->ep);
 390         }
 391         mutex_unlock(&data->lock);
 392         put_ep (data);
 393         return 0;
 394 }
 395
 396 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 397 {
 398         struct ep_data          *data = fd->private_data;
 399         int                     status;
 400
 401         if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
 402                 return status;
 403
 404         spin_lock_irq (&data->dev->lock);
 405         if (likely (data->ep != NULL)) {
 406                 switch (code) {
 407                 case GADGETFS_FIFO_STATUS:
 408                         status = usb_ep_fifo_status (data->ep);
 409                         break;
 410                 case GADGETFS_FIFO_FLUSH:
 411                         usb_ep_fifo_flush (data->ep);
 412                         break;
 413                 case GADGETFS_CLEAR_HALT:
 414                         status = usb_ep_clear_halt (data->ep);
 415                         break;
 416                 default:
 417                         status = -ENOTTY;
 418                 }
 419         } else
 420                 status = -ENODEV;
 421         spin_unlock_irq (&data->dev->lock);
 422         mutex_unlock(&data->lock);
 423         return status;
 424 }
 425
 426 /*----------------------------------------------------------------------*/
 427
 428 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 429
 430 struct kiocb_priv {
 431         struct usb_request      *req;
 432         struct ep_data          *epdata;
 433         struct kiocb            *iocb;
 434         struct mm_struct        *mm;
 435         struct work_struct      work;
 436         void                    *buf;
 437         struct iov_iter         to;
 438         const void              *to_free;
 439         unsigned                actual;
 440 };
 441
 442 static int ep_aio_cancel(struct kiocb *iocb)
 443 {
 444         struct kiocb_priv       *priv = iocb->private;
 445         struct ep_data          *epdata;
 446         int                     value;
 447
 448         local_irq_disable();
 449         epdata = priv->epdata;
 450         // spin_lock(&epdata->dev->lock);
 451         if (likely(epdata && epdata->ep && priv->req))
 452                 value = usb_ep_dequeue (epdata->ep, priv->req);
 453         else
 454                 value = -EINVAL;
 455         // spin_unlock(&epdata->dev->lock);
 456         local_irq_enable();
 457
 458         return value;
 459 }
 460
 461 static void ep_user_copy_worker(struct work_struct *work)
 462 {
 463         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 464         struct mm_struct *mm = priv->mm;
 465         struct kiocb *iocb = priv->iocb;
 466         size_t ret;
 467
 468         use_mm(mm);
 469         ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
 470         unuse_mm(mm);
 471         if (!ret)
 472                 ret = -EFAULT;
 473
 474         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 475         iocb->ki_complete(iocb, ret, ret);
 476
 477         kfree(priv->buf);
 478         kfree(priv->to_free);
 479         kfree(priv);
 480 }
 481
 482 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 483 {
 484         struct kiocb            *iocb = req->context;
 485         struct kiocb_priv       *priv = iocb->private;
 486         struct ep_data          *epdata = priv->epdata;
 487
 488         /* lock against disconnect (and ideally, cancel) */
 489         spin_lock(&epdata->dev->lock);
 490         priv->req = NULL;
 491         priv->epdata = NULL;
 492
 493         /* if this was a write or a read returning no data then we
 494          * don't need to copy anything to userspace, so we can
 495          * complete the aio request immediately.
 496          */
 497         if (priv->to_free == NULL || unlikely(req->actual == 0)) {
 498                 kfree(req->buf);
 499                 kfree(priv->to_free);
 500                 kfree(priv);
 501                 iocb->private = NULL;
 502                 /* aio_complete() reports bytes-transferred _and_ faults */
 503
 504                 iocb->ki_complete(iocb, req->actual ? req->actual : req->status,
 505                                 req->status);
 506         } else {
 507                 /* ep_copy_to_user() won't report both; we hide some faults */
 508                 if (unlikely(0 != req->status))
 509                         DBG(epdata->dev, "%s fault %d len %d\n",
 510                                 ep->name, req->status, req->actual);
 511
 512                 priv->buf = req->buf;
 513                 priv->actual = req->actual;
 514                 INIT_WORK(&priv->work, ep_user_copy_worker);
 515                 schedule_work(&priv->work);
 516         }
 517
 518         usb_ep_free_request(ep, req);
 519         spin_unlock(&epdata->dev->lock);
 520         put_ep(epdata);
 521 }
 522
 523 static ssize_t ep_aio(struct kiocb *iocb,
 524                       struct kiocb_priv *priv,
 525                       struct ep_data *epdata,
 526                       char *buf,
 527                       size_t len)
 528 {
 529         struct usb_request *req;
 530         ssize_t value;
 531
 532         iocb->private = priv;
 533         priv->iocb = iocb;
 534
 535         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 536         get_ep(epdata);
 537         priv->epdata = epdata;
 538         priv->actual = 0;
 539         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 540
 541         /* each kiocb is coupled to one usb_request, but we can't
 542          * allocate or submit those if the host disconnected.
 543          */
 544         spin_lock_irq(&epdata->dev->lock);
 545         value = -ENODEV;
 546         if (unlikely(epdata->ep == NULL))
 547                 goto fail;
 548
 549         req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 550         value = -ENOMEM;
 551         if (unlikely(!req))
 552                 goto fail;
 553
 554         priv->req = req;
 555         req->buf = buf;
 556         req->length = len;
 557         req->complete = ep_aio_complete;
 558         req->context = iocb;
 559         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 560         if (unlikely(0 != value)) {
 561                 usb_ep_free_request(epdata->ep, req);
 562                 goto fail;
 563         }
 564         spin_unlock_irq(&epdata->dev->lock);
 565         return -EIOCBQUEUED;
 566
 567 fail:
 568         spin_unlock_irq(&epdata->dev->lock);
 569         kfree(priv->to_free);
 570         kfree(priv);
 571         put_ep(epdata);
 572         return value;
 573 }
 574
 575 static ssize_t
 576 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 577 {
 578         struct file *file = iocb->ki_filp;
 579         struct ep_data *epdata = file->private_data;
 580         size_t len = iov_iter_count(to);
 581         ssize_t value;
 582         char *buf;
 583
 584         if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
 585                 return value;
 586
 587         /* halt any endpoint by doing a "wrong direction" i/o call */
 588         if (usb_endpoint_dir_in(&epdata->desc)) {
 589                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 590                     !is_sync_kiocb(iocb)) {
 591                         mutex_unlock(&epdata->lock);
 592                         return -EINVAL;
 593                 }
 594                 DBG (epdata->dev, "%s halt\n", epdata->name);
 595                 spin_lock_irq(&epdata->dev->lock);
 596                 if (likely(epdata->ep != NULL))
 597                         usb_ep_set_halt(epdata->ep);
 598                 spin_unlock_irq(&epdata->dev->lock);
 599                 mutex_unlock(&epdata->lock);
 600                 return -EBADMSG;
 601         }
 602
 603         buf = kmalloc(len, GFP_KERNEL);
 604         if (unlikely(!buf)) {
 605                 mutex_unlock(&epdata->lock);
 606                 return -ENOMEM;
 607         }
 608         if (is_sync_kiocb(iocb)) {
 609                 value = ep_io(epdata, buf, len);
 610                 if (value >= 0 && (copy_to_iter(buf, value, to) != value))
 611                         value = -EFAULT;
 612         } else {
 613                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 614                 value = -ENOMEM;
 615                 if (!priv)
 616                         goto fail;
 617                 priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
 618                 if (!priv->to_free) {
 619                         kfree(priv);
 620                         goto fail;
 621                 }
 622                 value = ep_aio(iocb, priv, epdata, buf, len);
 623                 if (value == -EIOCBQUEUED)
 624                         buf = NULL;
 625         }
 626 fail:
 627         kfree(buf);
 628         mutex_unlock(&epdata->lock);
 629         return value;
 630 }
 631
 632 static ssize_t ep_config(struct ep_data *, const char *, size_t);
 633
 634 static ssize_t
 635 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 636 {
 637         struct file *file = iocb->ki_filp;
 638         struct ep_data *epdata = file->private_data;
 639         size_t len = iov_iter_count(from);
 640         bool configured;
 641         ssize_t value;
 642         char *buf;
 643
 644         if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
 645                 return value;
 646
 647         configured = epdata->state == STATE_EP_ENABLED;
 648
 649         /* halt any endpoint by doing a "wrong direction" i/o call */
 650         if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
 651                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 652                     !is_sync_kiocb(iocb)) {
 653                         mutex_unlock(&epdata->lock);
 654                         return -EINVAL;
 655                 }
 656                 DBG (epdata->dev, "%s halt\n", epdata->name);
 657                 spin_lock_irq(&epdata->dev->lock);
 658                 if (likely(epdata->ep != NULL))
 659                         usb_ep_set_halt(epdata->ep);
 660                 spin_unlock_irq(&epdata->dev->lock);
 661                 mutex_unlock(&epdata->lock);
 662                 return -EBADMSG;
 663         }
 664
 665         buf = kmalloc(len, GFP_KERNEL);
 666         if (unlikely(!buf)) {
 667                 mutex_unlock(&epdata->lock);
 668                 return -ENOMEM;
 669         }
 670
 671         if (unlikely(!copy_from_iter_full(buf, len, from))) {
 672                 value = -EFAULT;
 673                 goto out;
 674         }
 675
 676         if (unlikely(!configured)) {
 677                 value = ep_config(epdata, buf, len);
 678         } else if (is_sync_kiocb(iocb)) {
 679                 value = ep_io(epdata, buf, len);
 680         } else {
 681                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 682                 value = -ENOMEM;
 683                 if (priv) {
 684                         value = ep_aio(iocb, priv, epdata, buf, len);
 685                         if (value == -EIOCBQUEUED)
 686                                 buf = NULL;
 687                 }
 688         }
 689 out:
 690         kfree(buf);
 691         mutex_unlock(&epdata->lock);
 692         return value;
 693 }
 694
 695 /*----------------------------------------------------------------------*/
 696
 697 /* used after endpoint configuration */
 698 static const struct file_operations ep_io_operations = {
 699         .owner =        THIS_MODULE,
 700
 701         .open =         ep_open,
 702         .release =      ep_release,
 703         .llseek =       no_llseek,
 704         .unlocked_ioctl = ep_ioctl,
 705         .read_iter =    ep_read_iter,
 706         .write_iter =   ep_write_iter,
 707 };
 708
 709 /* ENDPOINT INITIALIZATION
 710  *
 711  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 712  *     status = write (fd, descriptors, sizeof descriptors)
 713  *
 714  * That write establishes the endpoint configuration, configuring
 715  * the controller to process bulk, interrupt, or isochronous transfers
 716  * at the right maxpacket size, and so on.
 717  *
 718  * The descriptors are message type 1, identified by a host order u32
 719  * at the beginning of what's written.  Descriptor order is: full/low
 720  * speed descriptor, then optional high speed descriptor.
 721  */
 722 static ssize_t
 723 ep_config (struct ep_data *data, const char *buf, size_t len)
 724 {
 725         struct usb_ep           *ep;
 726         u32                     tag;
 727         int                     value, length = len;
 728
 729         if (data->state != STATE_EP_READY) {
 730                 value = -EL2HLT;
 731                 goto fail;
 732         }
 733
 734         value = len;
 735         if (len < USB_DT_ENDPOINT_SIZE + 4)
 736                 goto fail0;
 737
 738         /* we might need to change message format someday */
 739         memcpy(&tag, buf, 4);
 740         if (tag != 1) {
 741                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 742                 goto fail0;
 743         }
 744         buf += 4;
 745         len -= 4;
 746
 747         /* NOTE:  audio endpoint extensions not accepted here;
 748          * just don't include the extra bytes.
 749          */
 750
 751         /* full/low speed descriptor, then high speed */
 752         memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
 753         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 754                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 755                 goto fail0;
 756         if (len != USB_DT_ENDPOINT_SIZE) {
 757                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 758                         goto fail0;
 759                 memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 760                         USB_DT_ENDPOINT_SIZE);
 761                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 762                                 || data->hs_desc.bDescriptorType
 763                                         != USB_DT_ENDPOINT) {
 764                         DBG(data->dev, "config %s, bad hs length or type\n",
 765                                         data->name);
 766                         goto fail0;
 767                 }
 768         }
 769
 770         spin_lock_irq (&data->dev->lock);
 771         if (data->dev->state == STATE_DEV_UNBOUND) {
 772                 value = -ENOENT;
 773                 goto gone;
 774         } else {
 775                 ep = data->ep;
 776                 if (ep == NULL) {
 777                         value = -ENODEV;
 778                         goto gone;
 779                 }
 780         }
 781         switch (data->dev->gadget->speed) {
 782         case USB_SPEED_LOW:
 783         case USB_SPEED_FULL:
 784                 ep->desc = &data->desc;
 785                 break;
 786         case USB_SPEED_HIGH:
 787                 /* fails if caller didn't provide that descriptor... */
 788                 ep->desc = &data->hs_desc;
 789                 break;
 790         default:
 791                 DBG(data->dev, "unconnected, %s init abandoned\n",
 792                                 data->name);
 793                 value = -EINVAL;
 794                 goto gone;
 795         }
 796         value = usb_ep_enable(ep);
 797         if (value == 0) {
 798                 data->state = STATE_EP_ENABLED;
 799                 value = length;
 800         }
 801 gone:
 802         spin_unlock_irq (&data->dev->lock);
 803         if (value < 0) {
 804 fail:
 805                 data->desc.bDescriptorType = 0;
 806                 data->hs_desc.bDescriptorType = 0;
 807         }
 808         return value;
 809 fail0:
 810         value = -EINVAL;
 811         goto fail;
 812 }
 813
 814 static int
 815 ep_open (struct inode *inode, struct file *fd)
 816 {
 817         struct ep_data          *data = inode->i_private;
 818         int                     value = -EBUSY;
 819
 820         if (mutex_lock_interruptible(&data->lock) != 0)
 821                 return -EINTR;
 822         spin_lock_irq (&data->dev->lock);
 823         if (data->dev->state == STATE_DEV_UNBOUND)
 824                 value = -ENOENT;
 825         else if (data->state == STATE_EP_DISABLED) {
 826                 value = 0;
 827                 data->state = STATE_EP_READY;
 828                 get_ep (data);
 829                 fd->private_data = data;
 830                 VDEBUG (data->dev, "%s ready\n", data->name);
 831         } else
 832                 DBG (data->dev, "%s state %d\n",
 833                         data->name, data->state);
 834         spin_unlock_irq (&data->dev->lock);
 835         mutex_unlock(&data->lock);
 836         return value;
 837 }
 838
 839 /*----------------------------------------------------------------------*/
 840
 841 /* EP0 IMPLEMENTATION can be partly in userspace.
 842  *
 843  * Drivers that use this facility receive various events, including
 844  * control requests the kernel doesn't handle.  Drivers that don't
 845  * use this facility may be too simple-minded for real applications.
 846  */
 847
 848 static inline void ep0_readable (struct dev_data *dev)
 849 {
 850         wake_up (&dev->wait);
 851         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 852 }
 853
 854 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 855 {
 856         struct dev_data         *dev = ep->driver_data;
 857
 858         if (req->buf != dev->rbuf) {
 859                 kfree(req->buf);
 860                 req->buf = dev->rbuf;
 861         }
 862         req->complete = epio_complete;
 863         dev->setup_out_ready = 0;
 864 }
 865
 866 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 867 {
 868         struct dev_data         *dev = ep->driver_data;
 869         unsigned long           flags;
 870         int                     free = 1;
 871
 872         /* for control OUT, data must still get to userspace */
 873         spin_lock_irqsave(&dev->lock, flags);
 874         if (!dev->setup_in) {
 875                 dev->setup_out_error = (req->status != 0);
 876                 if (!dev->setup_out_error)
 877                         free = 0;
 878                 dev->setup_out_ready = 1;
 879                 ep0_readable (dev);
 880         }
 881
 882         /* clean up as appropriate */
 883         if (free && req->buf != &dev->rbuf)
 884                 clean_req (ep, req);
 885         req->complete = epio_complete;
 886         spin_unlock_irqrestore(&dev->lock, flags);
 887 }
 888
 889 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 890 {
 891         struct dev_data *dev = ep->driver_data;
 892
 893         if (dev->setup_out_ready) {
 894                 DBG (dev, "ep0 request busy!\n");
 895                 return -EBUSY;
 896         }
 897         if (len > sizeof (dev->rbuf))
 898                 req->buf = kmalloc(len, GFP_ATOMIC);
 899         if (req->buf == NULL) {
 900                 req->buf = dev->rbuf;
 901                 return -ENOMEM;
 902         }
 903         req->complete = ep0_complete;
 904         req->length = len;
 905         req->zero = 0;
 906         return 0;
 907 }
 908
 909 static ssize_t
 910 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 911 {
 912         struct dev_data                 *dev = fd->private_data;
 913         ssize_t                         retval;
 914         enum ep0_state                  state;
 915
 916         spin_lock_irq (&dev->lock);
 917         if (dev->state <= STATE_DEV_OPENED) {
 918                 retval = -EINVAL;
 919                 goto done;
 920         }
 921
 922         /* report fd mode change before acting on it */
 923         if (dev->setup_abort) {
 924                 dev->setup_abort = 0;
 925                 retval = -EIDRM;
 926                 goto done;
 927         }
 928
 929         /* control DATA stage */
 930         if ((state = dev->state) == STATE_DEV_SETUP) {
 931
 932                 if (dev->setup_in) {            /* stall IN */
 933                         VDEBUG(dev, "ep0in stall\n");
 934                         (void) usb_ep_set_halt (dev->gadget->ep0);
 935                         retval = -EL2HLT;
 936                         dev->state = STATE_DEV_CONNECTED;
 937
 938                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
 939                         struct usb_ep           *ep = dev->gadget->ep0;
 940                         struct usb_request      *req = dev->req;
 941
 942                         if ((retval = setup_req (ep, req, 0)) == 0) {
 943                                 ++dev->udc_usage;
 944                                 spin_unlock_irq (&dev->lock);
 945                                 retval = usb_ep_queue (ep, req, GFP_KERNEL);
 946                                 spin_lock_irq (&dev->lock);
 947                                 --dev->udc_usage;
 948                         }
 949                         dev->state = STATE_DEV_CONNECTED;
 950
 951                         /* assume that was SET_CONFIGURATION */
 952                         if (dev->current_config) {
 953                                 unsigned power;
 954
 955                                 if (gadget_is_dualspeed(dev->gadget)
 956                                                 && (dev->gadget->speed
 957                                                         == USB_SPEED_HIGH))
 958                                         power = dev->hs_config->bMaxPower;
 959                                 else
 960                                         power = dev->config->bMaxPower;
 961                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
 962                         }
 963
 964                 } else {                        /* collect OUT data */
 965                         if ((fd->f_flags & O_NONBLOCK) != 0
 966                                         && !dev->setup_out_ready) {
 967                                 retval = -EAGAIN;
 968                                 goto done;
 969                         }
 970                         spin_unlock_irq (&dev->lock);
 971                         retval = wait_event_interruptible (dev->wait,
 972                                         dev->setup_out_ready != 0);
 973
 974                         /* FIXME state could change from under us */
 975                         spin_lock_irq (&dev->lock);
 976                         if (retval)
 977                                 goto done;
 978
 979                         if (dev->state != STATE_DEV_SETUP) {
 980                                 retval = -ECANCELED;
 981                                 goto done;
 982                         }
 983                         dev->state = STATE_DEV_CONNECTED;
 984
 985                         if (dev->setup_out_error)
 986                                 retval = -EIO;
 987                         else {
 988                                 len = min (len, (size_t)dev->req->actual);
 989                                 ++dev->udc_usage;
 990                                 spin_unlock_irq(&dev->lock);
 991                                 if (copy_to_user (buf, dev->req->buf, len))
 992                                         retval = -EFAULT;
 993                                 else
 994                                         retval = len;
 995                                 spin_lock_irq(&dev->lock);
 996                                 --dev->udc_usage;
 997                                 clean_req (dev->gadget->ep0, dev->req);
 998                                 /* NOTE userspace can't yet choose to stall */
 999                         }
1000                 }
1001                 goto done;
1002         }
1003
1004         /* else normal: return event data */
1005         if (len < sizeof dev->event [0]) {
1006                 retval = -EINVAL;
1007                 goto done;
1008         }
1009         len -= len % sizeof (struct usb_gadgetfs_event);
1010         dev->usermode_setup = 1;
1011
1012 scan:
1013         /* return queued events right away */
1014         if (dev->ev_next != 0) {
1015                 unsigned                i, n;
1016
1017                 n = len / sizeof (struct usb_gadgetfs_event);
1018                 if (dev->ev_next < n)
1019                         n = dev->ev_next;
1020
1021                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1022                 for (i = 0; i < n; i++) {
1023                         if (dev->event [i].type == GADGETFS_SETUP) {
1024                                 dev->state = STATE_DEV_SETUP;
1025                                 n = i + 1;
1026                                 break;
1027                         }
1028                 }
1029                 spin_unlock_irq (&dev->lock);
1030                 len = n * sizeof (struct usb_gadgetfs_event);
1031                 if (copy_to_user (buf, &dev->event, len))
1032                         retval = -EFAULT;
1033                 else
1034                         retval = len;
1035                 if (len > 0) {
1036                         /* NOTE this doesn't guard against broken drivers;
1037                          * concurrent ep0 readers may lose events.
1038                          */
1039                         spin_lock_irq (&dev->lock);
1040                         if (dev->ev_next > n) {
1041                                 memmove(&dev->event[0], &dev->event[n],
1042                                         sizeof (struct usb_gadgetfs_event)
1043                                                 * (dev->ev_next - n));
1044                         }
1045                         dev->ev_next -= n;
1046                         spin_unlock_irq (&dev->lock);
1047                 }
1048                 return retval;
1049         }
1050         if (fd->f_flags & O_NONBLOCK) {
1051                 retval = -EAGAIN;
1052                 goto done;
1053         }
1054
1055         switch (state) {
1056         default:
1057                 DBG (dev, "fail %s, state %d\n", __func__, state);
1058                 retval = -ESRCH;
1059                 break;
1060         case STATE_DEV_UNCONNECTED:
1061         case STATE_DEV_CONNECTED:
1062                 spin_unlock_irq (&dev->lock);
1063                 DBG (dev, "%s wait\n", __func__);
1064
1065                 /* wait for events */
1066                 retval = wait_event_interruptible (dev->wait,
1067                                 dev->ev_next != 0);
1068                 if (retval < 0)
1069                         return retval;
1070                 spin_lock_irq (&dev->lock);
1071                 goto scan;
1072         }
1073
1074 done:
1075         spin_unlock_irq (&dev->lock);
1076         return retval;
1077 }
1078
1079 static struct usb_gadgetfs_event *
1080 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1081 {
1082         struct usb_gadgetfs_event       *event;
1083         unsigned                        i;
1084
1085         switch (type) {
1086         /* these events purge the queue */
1087         case GADGETFS_DISCONNECT:
1088                 if (dev->state == STATE_DEV_SETUP)
1089                         dev->setup_abort = 1;
1090                 // FALL THROUGH
1091         case GADGETFS_CONNECT:
1092                 dev->ev_next = 0;
1093                 break;
1094         case GADGETFS_SETUP:            /* previous request timed out */
1095         case GADGETFS_SUSPEND:          /* same effect */
1096                 /* these events can't be repeated */
1097                 for (i = 0; i != dev->ev_next; i++) {
1098                         if (dev->event [i].type != type)
1099                                 continue;
1100                         DBG(dev, "discard old event[%d] %d\n", i, type);
1101                         dev->ev_next--;
1102                         if (i == dev->ev_next)
1103                                 break;
1104                         /* indices start at zero, for simplicity */
1105                         memmove (&dev->event [i], &dev->event [i + 1],
1106                                 sizeof (struct usb_gadgetfs_event)
1107                                         * (dev->ev_next - i));
1108                 }
1109                 break;
1110         default:
1111                 BUG ();
1112         }
1113         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1114         event = &dev->event [dev->ev_next++];
1115         BUG_ON (dev->ev_next > N_EVENT);
1116         memset (event, 0, sizeof *event);
1117         event->type = type;
1118         return event;
1119 }
1120
1121 static ssize_t
1122 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1123 {
1124         struct dev_data         *dev = fd->private_data;
1125         ssize_t                 retval = -ESRCH;
1126
1127         /* report fd mode change before acting on it */
1128         if (dev->setup_abort) {
1129                 dev->setup_abort = 0;
1130                 retval = -EIDRM;
1131
1132         /* data and/or status stage for control request */
1133         } else if (dev->state == STATE_DEV_SETUP) {
1134
1135                 len = min_t(size_t, len, dev->setup_wLength);
1136                 if (dev->setup_in) {
1137                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1138                         if (retval == 0) {
1139                                 dev->state = STATE_DEV_CONNECTED;
1140                                 ++dev->udc_usage;
1141                                 spin_unlock_irq (&dev->lock);
1142                                 if (copy_from_user (dev->req->buf, buf, len))
1143                                         retval = -EFAULT;
1144                                 else {
1145                                         if (len < dev->setup_wLength)
1146                                                 dev->req->zero = 1;
1147                                         retval = usb_ep_queue (
1148                                                 dev->gadget->ep0, dev->req,
1149                                                 GFP_KERNEL);
1150                                 }
1151                                 spin_lock_irq(&dev->lock);
1152                                 --dev->udc_usage;
1153                                 if (retval < 0) {
1154                                         clean_req (dev->gadget->ep0, dev->req);
1155                                 } else
1156                                         retval = len;
1157
1158                                 return retval;
1159                         }
1160
1161                 /* can stall some OUT transfers */
1162                 } else if (dev->setup_can_stall) {
1163                         VDEBUG(dev, "ep0out stall\n");
1164                         (void) usb_ep_set_halt (dev->gadget->ep0);
1165                         retval = -EL2HLT;
1166                         dev->state = STATE_DEV_CONNECTED;
1167                 } else {
1168                         DBG(dev, "bogus ep0out stall!\n");
1169                 }
1170         } else
1171                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1172
1173         return retval;
1174 }
1175
1176 static int
1177 ep0_fasync (int f, struct file *fd, int on)
1178 {
1179         struct dev_data         *dev = fd->private_data;
1180         // caller must F_SETOWN before signal delivery happens
1181         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1182         return fasync_helper (f, fd, on, &dev->fasync);
1183 }
1184
1185 static struct usb_gadget_driver gadgetfs_driver;
1186
1187 static int
1188 dev_release (struct inode *inode, struct file *fd)
1189 {
1190         struct dev_data         *dev = fd->private_data;
1191
1192         /* closing ep0 === shutdown all */
1193
1194         if (dev->gadget_registered) {
1195                 usb_gadget_unregister_driver (&gadgetfs_driver);
1196                 dev->gadget_registered = false;
1197         }
1198
1199         /* at this point "good" hardware has disconnected the
1200          * device from USB; the host won't see it any more.
1201          * alternatively, all host requests will time out.
1202          */
1203
1204         kfree (dev->buf);
1205         dev->buf = NULL;
1206
1207         /* other endpoints were all decoupled from this device */
1208         spin_lock_irq(&dev->lock);
1209         dev->state = STATE_DEV_DISABLED;
1210         spin_unlock_irq(&dev->lock);
1211
1212         put_dev (dev);
1213         return 0;
1214 }
1215
1216 static unsigned int
1217 ep0_poll (struct file *fd, poll_table *wait)
1218 {
1219        struct dev_data         *dev = fd->private_data;
1220        int                     mask = 0;
1221
1222         if (dev->state <= STATE_DEV_OPENED)
1223                 return DEFAULT_POLLMASK;
1224
1225        poll_wait(fd, &dev->wait, wait);
1226
1227        spin_lock_irq (&dev->lock);
1228
1229        /* report fd mode change before acting on it */
1230        if (dev->setup_abort) {
1231                dev->setup_abort = 0;
1232                mask = POLLHUP;
1233                goto out;
1234        }
1235
1236        if (dev->state == STATE_DEV_SETUP) {
1237                if (dev->setup_in || dev->setup_can_stall)
1238                        mask = POLLOUT;
1239        } else {
1240                if (dev->ev_next != 0)
1241                        mask = POLLIN;
1242        }
1243 out:
1244        spin_unlock_irq(&dev->lock);
1245        return mask;
1246 }
1247
1248 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1249 {
1250         struct dev_data         *dev = fd->private_data;
1251         struct usb_gadget       *gadget = dev->gadget;
1252         long ret = -ENOTTY;
1253
1254         spin_lock_irq(&dev->lock);
1255         if (dev->state == STATE_DEV_OPENED ||
1256                         dev->state == STATE_DEV_UNBOUND) {
1257                 /* Not bound to a UDC */
1258         } else if (gadget->ops->ioctl) {
1259                 ++dev->udc_usage;
1260                 spin_unlock_irq(&dev->lock);
1261
1262                 ret = gadget->ops->ioctl (gadget, code, value);
1263
1264                 spin_lock_irq(&dev->lock);
1265                 --dev->udc_usage;
1266         }
1267         spin_unlock_irq(&dev->lock);
1268
1269         return ret;
1270 }
1271
1272 /*----------------------------------------------------------------------*/
1273
1274 /* The in-kernel gadget driver handles most ep0 issues, in particular
1275  * enumerating the single configuration (as provided from user space).
1276  *
1277  * Unrecognized ep0 requests may be handled in user space.
1278  */
1279
1280 static void make_qualifier (struct dev_data *dev)
1281 {
1282         struct usb_qualifier_descriptor         qual;
1283         struct usb_device_descriptor            *desc;
1284
1285         qual.bLength = sizeof qual;
1286         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1287         qual.bcdUSB = cpu_to_le16 (0x0200);
1288
1289         desc = dev->dev;
1290         qual.bDeviceClass = desc->bDeviceClass;
1291         qual.bDeviceSubClass = desc->bDeviceSubClass;
1292         qual.bDeviceProtocol = desc->bDeviceProtocol;
1293
1294         /* assumes ep0 uses the same value for both speeds ... */
1295         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1296
1297         qual.bNumConfigurations = 1;
1298         qual.bRESERVED = 0;
1299
1300         memcpy (dev->rbuf, &qual, sizeof qual);
1301 }
1302
1303 static int
1304 config_buf (struct dev_data *dev, u8 type, unsigned index)
1305 {
1306         int             len;
1307         int             hs = 0;
1308
1309         /* only one configuration */
1310         if (index > 0)
1311                 return -EINVAL;
1312
1313         if (gadget_is_dualspeed(dev->gadget)) {
1314                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1315                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1316                         hs = !hs;
1317         }
1318         if (hs) {
1319                 dev->req->buf = dev->hs_config;
1320                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1321         } else {
1322                 dev->req->buf = dev->config;
1323                 len = le16_to_cpu(dev->config->wTotalLength);
1324         }
1325         ((u8 *)dev->req->buf) [1] = type;
1326         return len;
1327 }
1328
1329 static int
1330 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1331 {
1332         struct dev_data                 *dev = get_gadget_data (gadget);
1333         struct usb_request              *req = dev->req;
1334         int                             value = -EOPNOTSUPP;
1335         struct usb_gadgetfs_event       *event;
1336         u16                             w_value = le16_to_cpu(ctrl->wValue);
1337         u16                             w_length = le16_to_cpu(ctrl->wLength);
1338
1339         spin_lock (&dev->lock);
1340         dev->setup_abort = 0;
1341         if (dev->state == STATE_DEV_UNCONNECTED) {
1342                 if (gadget_is_dualspeed(gadget)
1343                                 && gadget->speed == USB_SPEED_HIGH
1344                                 && dev->hs_config == NULL) {
1345                         spin_unlock(&dev->lock);
1346                         ERROR (dev, "no high speed config??\n");
1347                         return -EINVAL;
1348                 }
1349
1350                 dev->state = STATE_DEV_CONNECTED;
1351
1352                 INFO (dev, "connected\n");
1353                 event = next_event (dev, GADGETFS_CONNECT);
1354                 event->u.speed = gadget->speed;
1355                 ep0_readable (dev);
1356
1357         /* host may have given up waiting for response.  we can miss control
1358          * requests handled lower down (device/endpoint status and features);
1359          * then ep0_{read,write} will report the wrong status. controller
1360          * driver will have aborted pending i/o.
1361          */
1362         } else if (dev->state == STATE_DEV_SETUP)
1363                 dev->setup_abort = 1;
1364
1365         req->buf = dev->rbuf;
1366         req->context = NULL;
1367         switch (ctrl->bRequest) {
1368
1369         case USB_REQ_GET_DESCRIPTOR:
1370                 if (ctrl->bRequestType != USB_DIR_IN)
1371                         goto unrecognized;
1372                 switch (w_value >> 8) {
1373
1374                 case USB_DT_DEVICE:
1375                         value = min (w_length, (u16) sizeof *dev->dev);
1376                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1377                         req->buf = dev->dev;
1378                         break;
1379                 case USB_DT_DEVICE_QUALIFIER:
1380                         if (!dev->hs_config)
1381                                 break;
1382                         value = min (w_length, (u16)
1383                                 sizeof (struct usb_qualifier_descriptor));
1384                         make_qualifier (dev);
1385                         break;
1386                 case USB_DT_OTHER_SPEED_CONFIG:
1387                         // FALLTHROUGH
1388                 case USB_DT_CONFIG:
1389                         value = config_buf (dev,
1390                                         w_value >> 8,
1391                                         w_value & 0xff);
1392                         if (value >= 0)
1393                                 value = min (w_length, (u16) value);
1394                         break;
1395                 case USB_DT_STRING:
1396                         goto unrecognized;
1397
1398                 default:                // all others are errors
1399                         break;
1400                 }
1401                 break;
1402
1403         /* currently one config, two speeds */
1404         case USB_REQ_SET_CONFIGURATION:
1405                 if (ctrl->bRequestType != 0)
1406                         goto unrecognized;
1407                 if (0 == (u8) w_value) {
1408                         value = 0;
1409                         dev->current_config = 0;
1410                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1411                         // user mode expected to disable endpoints
1412                 } else {
1413                         u8      config, power;
1414
1415                         if (gadget_is_dualspeed(gadget)
1416                                         && gadget->speed == USB_SPEED_HIGH) {
1417                                 config = dev->hs_config->bConfigurationValue;
1418                                 power = dev->hs_config->bMaxPower;
1419                         } else {
1420                                 config = dev->config->bConfigurationValue;
1421                                 power = dev->config->bMaxPower;
1422                         }
1423
1424                         if (config == (u8) w_value) {
1425                                 value = 0;
1426                                 dev->current_config = config;
1427                                 usb_gadget_vbus_draw(gadget, 2 * power);
1428                         }
1429                 }
1430
1431                 /* report SET_CONFIGURATION like any other control request,
1432                  * except that usermode may not stall this.  the next
1433                  * request mustn't be allowed start until this finishes:
1434                  * endpoints and threads set up, etc.
1435                  *
1436                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1437                  * has bad/racey automagic that prevents synchronizing here.
1438                  * even kernel mode drivers often miss them.
1439                  */
1440                 if (value == 0) {
1441                         INFO (dev, "configuration #%d\n", dev->current_config);
1442                         usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1443                         if (dev->usermode_setup) {
1444                                 dev->setup_can_stall = 0;
1445                                 goto delegate;
1446                         }
1447                 }
1448                 break;
1449
1450 #ifndef CONFIG_USB_PXA25X
1451         /* PXA automagically handles this request too */
1452         case USB_REQ_GET_CONFIGURATION:
1453                 if (ctrl->bRequestType != 0x80)
1454                         goto unrecognized;
1455                 *(u8 *)req->buf = dev->current_config;
1456                 value = min (w_length, (u16) 1);
1457                 break;
1458 #endif
1459
1460         default:
1461 unrecognized:
1462                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1463                         dev->usermode_setup ? "delegate" : "fail",
1464                         ctrl->bRequestType, ctrl->bRequest,
1465                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1466
1467                 /* if there's an ep0 reader, don't stall */
1468                 if (dev->usermode_setup) {
1469                         dev->setup_can_stall = 1;
1470 delegate:
1471                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1472                                                 ? 1 : 0;
1473                         dev->setup_wLength = w_length;
1474                         dev->setup_out_ready = 0;
1475                         dev->setup_out_error = 0;
1476                         value = 0;
1477
1478                         /* read DATA stage for OUT right away */
1479                         if (unlikely (!dev->setup_in && w_length)) {
1480                                 value = setup_req (gadget->ep0, dev->req,
1481                                                         w_length);
1482                                 if (value < 0)
1483                                         break;
1484
1485                                 ++dev->udc_usage;
1486                                 spin_unlock (&dev->lock);
1487                                 value = usb_ep_queue (gadget->ep0, dev->req,
1488                                                         GFP_KERNEL);
1489                                 spin_lock (&dev->lock);
1490                                 --dev->udc_usage;
1491                                 if (value < 0) {
1492                                         clean_req (gadget->ep0, dev->req);
1493                                         break;
1494                                 }
1495
1496                                 /* we can't currently stall these */
1497                                 dev->setup_can_stall = 0;
1498                         }
1499
1500                         /* state changes when reader collects event */
1501                         event = next_event (dev, GADGETFS_SETUP);
1502                         event->u.setup = *ctrl;
1503                         ep0_readable (dev);
1504                         spin_unlock (&dev->lock);
1505                         return 0;
1506                 }
1507         }
1508
1509         /* proceed with data transfer and status phases? */
1510         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1511                 req->length = value;
1512                 req->zero = value < w_length;
1513
1514                 ++dev->udc_usage;
1515                 spin_unlock (&dev->lock);
1516                 value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1517                 spin_lock(&dev->lock);
1518                 --dev->udc_usage;
1519                 spin_unlock(&dev->lock);
1520                 if (value < 0) {
1521                         DBG (dev, "ep_queue --> %d\n", value);
1522                         req->status = 0;
1523                 }
1524                 return value;
1525         }
1526
1527         /* device stalls when value < 0 */
1528         spin_unlock (&dev->lock);
1529         return value;
1530 }
1531
1532 static void destroy_ep_files (struct dev_data *dev)
1533 {
1534         DBG (dev, "%s %d\n", __func__, dev->state);
1535
1536         /* dev->state must prevent interference */
1537         spin_lock_irq (&dev->lock);
1538         while (!list_empty(&dev->epfiles)) {
1539                 struct ep_data  *ep;
1540                 struct inode    *parent;
1541                 struct dentry   *dentry;
1542
1543                 /* break link to FS */
1544                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1545                 list_del_init (&ep->epfiles);
1546                 spin_unlock_irq (&dev->lock);
1547
1548                 dentry = ep->dentry;
1549                 ep->dentry = NULL;
1550                 parent = d_inode(dentry->d_parent);
1551
1552                 /* break link to controller */
1553                 mutex_lock(&ep->lock);
1554                 if (ep->state == STATE_EP_ENABLED)
1555                         (void) usb_ep_disable (ep->ep);
1556                 ep->state = STATE_EP_UNBOUND;
1557                 usb_ep_free_request (ep->ep, ep->req);
1558                 ep->ep = NULL;
1559                 mutex_unlock(&ep->lock);
1560
1561                 wake_up (&ep->wait);
1562                 put_ep (ep);
1563
1564                 /* break link to dcache */
1565                 inode_lock(parent);
1566                 d_delete (dentry);
1567                 dput (dentry);
1568                 inode_unlock(parent);
1569
1570                 spin_lock_irq (&dev->lock);
1571         }
1572         spin_unlock_irq (&dev->lock);
1573 }
1574
1575
1576 static struct dentry *
1577 gadgetfs_create_file (struct super_block *sb, char const *name,
1578                 void *data, const struct file_operations *fops);
1579
1580 static int activate_ep_files (struct dev_data *dev)
1581 {
1582         struct usb_ep   *ep;
1583         struct ep_data  *data;
1584
1585         gadget_for_each_ep (ep, dev->gadget) {
1586
1587                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1588                 if (!data)
1589                         goto enomem0;
1590                 data->state = STATE_EP_DISABLED;
1591                 mutex_init(&data->lock);
1592                 init_waitqueue_head (&data->wait);
1593
1594                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1595                 refcount_set (&data->count, 1);
1596                 data->dev = dev;
1597                 get_dev (dev);
1598
1599                 data->ep = ep;
1600                 ep->driver_data = data;
1601
1602                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1603                 if (!data->req)
1604                         goto enomem1;
1605
1606                 data->dentry = gadgetfs_create_file (dev->sb, data->name,
1607                                 data, &ep_io_operations);
1608                 if (!data->dentry)
1609                         goto enomem2;
1610                 list_add_tail (&data->epfiles, &dev->epfiles);
1611         }
1612         return 0;
1613
1614 enomem2:
1615         usb_ep_free_request (ep, data->req);
1616 enomem1:
1617         put_dev (dev);
1618         kfree (data);
1619 enomem0:
1620         DBG (dev, "%s enomem\n", __func__);
1621         destroy_ep_files (dev);
1622         return -ENOMEM;
1623 }
1624
1625 static void
1626 gadgetfs_unbind (struct usb_gadget *gadget)
1627 {
1628         struct dev_data         *dev = get_gadget_data (gadget);
1629
1630         DBG (dev, "%s\n", __func__);
1631
1632         spin_lock_irq (&dev->lock);
1633         dev->state = STATE_DEV_UNBOUND;
1634         while (dev->udc_usage > 0) {
1635                 spin_unlock_irq(&dev->lock);
1636                 usleep_range(1000, 2000);
1637                 spin_lock_irq(&dev->lock);
1638         }
1639         spin_unlock_irq (&dev->lock);
1640
1641         destroy_ep_files (dev);
1642         gadget->ep0->driver_data = NULL;
1643         set_gadget_data (gadget, NULL);
1644
1645         /* we've already been disconnected ... no i/o is active */
1646         if (dev->req)
1647                 usb_ep_free_request (gadget->ep0, dev->req);
1648         DBG (dev, "%s done\n", __func__);
1649         put_dev (dev);
1650 }
1651
1652 static struct dev_data          *the_device;
1653
1654 static int gadgetfs_bind(struct usb_gadget *gadget,
1655                 struct usb_gadget_driver *driver)
1656 {
1657         struct dev_data         *dev = the_device;
1658
1659         if (!dev)
1660                 return -ESRCH;
1661         if (0 != strcmp (CHIP, gadget->name)) {
1662                 pr_err("%s expected %s controller not %s\n",
1663                         shortname, CHIP, gadget->name);
1664                 return -ENODEV;
1665         }
1666
1667         set_gadget_data (gadget, dev);
1668         dev->gadget = gadget;
1669         gadget->ep0->driver_data = dev;
1670
1671         /* preallocate control response and buffer */
1672         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1673         if (!dev->req)
1674                 goto enomem;
1675         dev->req->context = NULL;
1676         dev->req->complete = epio_complete;
1677
1678         if (activate_ep_files (dev) < 0)
1679                 goto enomem;
1680
1681         INFO (dev, "bound to %s driver\n", gadget->name);
1682         spin_lock_irq(&dev->lock);
1683         dev->state = STATE_DEV_UNCONNECTED;
1684         spin_unlock_irq(&dev->lock);
1685         get_dev (dev);
1686         return 0;
1687
1688 enomem:
1689         gadgetfs_unbind (gadget);
1690         return -ENOMEM;
1691 }
1692
1693 static void
1694 gadgetfs_disconnect (struct usb_gadget *gadget)
1695 {
1696         struct dev_data         *dev = get_gadget_data (gadget);
1697         unsigned long           flags;
1698
1699         spin_lock_irqsave (&dev->lock, flags);
1700         if (dev->state == STATE_DEV_UNCONNECTED)
1701                 goto exit;
1702         dev->state = STATE_DEV_UNCONNECTED;
1703
1704         INFO (dev, "disconnected\n");
1705         next_event (dev, GADGETFS_DISCONNECT);
1706         ep0_readable (dev);
1707 exit:
1708         spin_unlock_irqrestore (&dev->lock, flags);
1709 }
1710
1711 static void
1712 gadgetfs_suspend (struct usb_gadget *gadget)
1713 {
1714         struct dev_data         *dev = get_gadget_data (gadget);
1715         unsigned long           flags;
1716
1717         INFO (dev, "suspended from state %d\n", dev->state);
1718         spin_lock_irqsave(&dev->lock, flags);
1719         switch (dev->state) {
1720         case STATE_DEV_SETUP:           // VERY odd... host died??
1721         case STATE_DEV_CONNECTED:
1722         case STATE_DEV_UNCONNECTED:
1723                 next_event (dev, GADGETFS_SUSPEND);
1724                 ep0_readable (dev);
1725                 /* FALLTHROUGH */
1726         default:
1727                 break;
1728         }
1729         spin_unlock_irqrestore(&dev->lock, flags);
1730 }
1731
1732 static struct usb_gadget_driver gadgetfs_driver = {
1733         .function       = (char *) driver_desc,
1734         .bind           = gadgetfs_bind,
1735         .unbind         = gadgetfs_unbind,
1736         .setup          = gadgetfs_setup,
1737         .reset          = gadgetfs_disconnect,
1738         .disconnect     = gadgetfs_disconnect,
1739         .suspend        = gadgetfs_suspend,
1740
1741         .driver = {
1742                 .name           = (char *) shortname,
1743         },
1744 };
1745
1746 /*----------------------------------------------------------------------*/
1747 /* DEVICE INITIALIZATION
1748  *
1749  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1750  *     status = write (fd, descriptors, sizeof descriptors)
1751  *
1752  * That write establishes the device configuration, so the kernel can
1753  * bind to the controller ... guaranteeing it can handle enumeration
1754  * at all necessary speeds.  Descriptor order is:
1755  *
1756  * . message tag (u32, host order) ... for now, must be zero; it
1757  *      would change to support features like multi-config devices
1758  * . full/low speed config ... all wTotalLength bytes (with interface,
1759  *      class, altsetting, endpoint, and other descriptors)
1760  * . high speed config ... all descriptors, for high speed operation;
1761  *      this one's optional except for high-speed hardware
1762  * . device descriptor
1763  *
1764  * Endpoints are not yet enabled. Drivers must wait until device
1765  * configuration and interface altsetting changes create
1766  * the need to configure (or unconfigure) them.
1767  *
1768  * After initialization, the device stays active for as long as that
1769  * $CHIP file is open.  Events must then be read from that descriptor,
1770  * such as configuration notifications.
1771  */
1772
1773 static int is_valid_config(struct usb_config_descriptor *config,
1774                 unsigned int total)
1775 {
1776         return config->bDescriptorType == USB_DT_CONFIG
1777                 && config->bLength == USB_DT_CONFIG_SIZE
1778                 && total >= USB_DT_CONFIG_SIZE
1779                 && config->bConfigurationValue != 0
1780                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1781                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1782         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1783         /* FIXME check lengths: walk to end */
1784 }
1785
1786 static ssize_t
1787 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1788 {
1789         struct dev_data         *dev = fd->private_data;
1790         ssize_t                 value, length = len;
1791         unsigned                total;
1792         u32                     tag;
1793         char                    *kbuf;
1794
1795         spin_lock_irq(&dev->lock);
1796         if (dev->state > STATE_DEV_OPENED) {
1797                 value = ep0_write(fd, buf, len, ptr);
1798                 spin_unlock_irq(&dev->lock);
1799                 return value;
1800         }
1801         spin_unlock_irq(&dev->lock);
1802
1803         if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1804             (len > PAGE_SIZE * 4))
1805                 return -EINVAL;
1806
1807         /* we might need to change message format someday */
1808         if (copy_from_user (&tag, buf, 4))
1809                 return -EFAULT;
1810         if (tag != 0)
1811                 return -EINVAL;
1812         buf += 4;
1813         length -= 4;
1814
1815         kbuf = memdup_user(buf, length);
1816         if (IS_ERR(kbuf))
1817                 return PTR_ERR(kbuf);
1818
1819         spin_lock_irq (&dev->lock);
1820         value = -EINVAL;
1821         if (dev->buf) {
1822                 kfree(kbuf);
1823                 goto fail;
1824         }
1825         dev->buf = kbuf;
1826
1827         /* full or low speed config */
1828         dev->config = (void *) kbuf;
1829         total = le16_to_cpu(dev->config->wTotalLength);
1830         if (!is_valid_config(dev->config, total) ||
1831                         total > length - USB_DT_DEVICE_SIZE)
1832                 goto fail;
1833         kbuf += total;
1834         length -= total;
1835
1836         /* optional high speed config */
1837         if (kbuf [1] == USB_DT_CONFIG) {
1838                 dev->hs_config = (void *) kbuf;
1839                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1840                 if (!is_valid_config(dev->hs_config, total) ||
1841                                 total > length - USB_DT_DEVICE_SIZE)
1842                         goto fail;
1843                 kbuf += total;
1844                 length -= total;
1845         } else {
1846                 dev->hs_config = NULL;
1847         }
1848
1849         /* could support multiple configs, using another encoding! */
1850
1851         /* device descriptor (tweaked for paranoia) */
1852         if (length != USB_DT_DEVICE_SIZE)
1853                 goto fail;
1854         dev->dev = (void *)kbuf;
1855         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1856                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1857                         || dev->dev->bNumConfigurations != 1)
1858                 goto fail;
1859         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1860
1861         /* triggers gadgetfs_bind(); then we can enumerate. */
1862         spin_unlock_irq (&dev->lock);
1863         if (dev->hs_config)
1864                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1865         else
1866                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1867
1868         value = usb_gadget_probe_driver(&gadgetfs_driver);
1869         if (value != 0) {
1870                 kfree (dev->buf);
1871                 dev->buf = NULL;
1872         } else {
1873                 /* at this point "good" hardware has for the first time
1874                  * let the USB the host see us.  alternatively, if users
1875                  * unplug/replug that will clear all the error state.
1876                  *
1877                  * note:  everything running before here was guaranteed
1878                  * to choke driver model style diagnostics.  from here
1879                  * on, they can work ... except in cleanup paths that
1880                  * kick in after the ep0 descriptor is closed.
1881                  */
1882                 value = len;
1883                 dev->gadget_registered = true;
1884         }
1885         return value;
1886
1887 fail:
1888         spin_unlock_irq (&dev->lock);
1889         pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev);
1890         kfree (dev->buf);
1891         dev->buf = NULL;
1892         return value;
1893 }
1894
1895 static int
1896 dev_open (struct inode *inode, struct file *fd)
1897 {
1898         struct dev_data         *dev = inode->i_private;
1899         int                     value = -EBUSY;
1900
1901         spin_lock_irq(&dev->lock);
1902         if (dev->state == STATE_DEV_DISABLED) {
1903                 dev->ev_next = 0;
1904                 dev->state = STATE_DEV_OPENED;
1905                 fd->private_data = dev;
1906                 get_dev (dev);
1907                 value = 0;
1908         }
1909         spin_unlock_irq(&dev->lock);
1910         return value;
1911 }
1912
1913 static const struct file_operations ep0_operations = {
1914         .llseek =       no_llseek,
1915
1916         .open =         dev_open,
1917         .read =         ep0_read,
1918         .write =        dev_config,
1919         .fasync =       ep0_fasync,
1920         .poll =         ep0_poll,
1921         .unlocked_ioctl = dev_ioctl,
1922         .release =      dev_release,
1923 };
1924
1925 /*----------------------------------------------------------------------*/
1926
1927 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1928  *
1929  * Mounting the filesystem creates a controller file, used first for
1930  * device configuration then later for event monitoring.
1931  */
1932
1933
1934 /* FIXME PAM etc could set this security policy without mount options
1935  * if epfiles inherited ownership and permissons from ep0 ...
1936  */
1937
1938 static unsigned default_uid;
1939 static unsigned default_gid;
1940 static unsigned default_perm = S_IRUSR | S_IWUSR;
1941
1942 module_param (default_uid, uint, 0644);
1943 module_param (default_gid, uint, 0644);
1944 module_param (default_perm, uint, 0644);
1945
1946
1947 static struct inode *
1948 gadgetfs_make_inode (struct super_block *sb,
1949                 void *data, const struct file_operations *fops,
1950                 int mode)
1951 {
1952         struct inode *inode = new_inode (sb);
1953
1954         if (inode) {
1955                 inode->i_ino = get_next_ino();
1956                 inode->i_mode = mode;
1957                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
1958                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
1959                 inode->i_atime = inode->i_mtime = inode->i_ctime
1960                                 = current_time(inode);
1961                 inode->i_private = data;
1962                 inode->i_fop = fops;
1963         }
1964         return inode;
1965 }
1966
1967 /* creates in fs root directory, so non-renamable and non-linkable.
1968  * so inode and dentry are paired, until device reconfig.
1969  */
1970 static struct dentry *
1971 gadgetfs_create_file (struct super_block *sb, char const *name,
1972                 void *data, const struct file_operations *fops)
1973 {
1974         struct dentry   *dentry;
1975         struct inode    *inode;
1976
1977         dentry = d_alloc_name(sb->s_root, name);
1978         if (!dentry)
1979                 return NULL;
1980
1981         inode = gadgetfs_make_inode (sb, data, fops,
1982                         S_IFREG | (default_perm & S_IRWXUGO));
1983         if (!inode) {
1984                 dput(dentry);
1985                 return NULL;
1986         }
1987         d_add (dentry, inode);
1988         return dentry;
1989 }
1990
1991 static const struct super_operations gadget_fs_operations = {
1992         .statfs =       simple_statfs,
1993         .drop_inode =   generic_delete_inode,
1994 };
1995
1996 static int
1997 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
1998 {
1999         struct inode    *inode;
2000         struct dev_data *dev;
2001
2002         if (the_device)
2003                 return -ESRCH;
2004
2005         CHIP = usb_get_gadget_udc_name();
2006         if (!CHIP)
2007                 return -ENODEV;
2008
2009         /* superblock */
2010         sb->s_blocksize = PAGE_SIZE;
2011         sb->s_blocksize_bits = PAGE_SHIFT;
2012         sb->s_magic = GADGETFS_MAGIC;
2013         sb->s_op = &gadget_fs_operations;
2014         sb->s_time_gran = 1;
2015
2016         /* root inode */
2017         inode = gadgetfs_make_inode (sb,
2018                         NULL, &simple_dir_operations,
2019                         S_IFDIR | S_IRUGO | S_IXUGO);
2020         if (!inode)
2021                 goto Enomem;
2022         inode->i_op = &simple_dir_inode_operations;
2023         if (!(sb->s_root = d_make_root (inode)))
2024                 goto Enomem;
2025
2026         /* the ep0 file is named after the controller we expect;
2027          * user mode code can use it for sanity checks, like we do.
2028          */
2029         dev = dev_new ();
2030         if (!dev)
2031                 goto Enomem;
2032
2033         dev->sb = sb;
2034         dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2035         if (!dev->dentry) {
2036                 put_dev(dev);
2037                 goto Enomem;
2038         }
2039
2040         /* other endpoint files are available after hardware setup,
2041          * from binding to a controller.
2042          */
2043         the_device = dev;
2044         return 0;
2045
2046 Enomem:
2047         kfree(CHIP);
2048         CHIP = NULL;
2049
2050         return -ENOMEM;
2051 }
2052
2053 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2054 static struct dentry *
2055 gadgetfs_mount (struct file_system_type *t, int flags,
2056                 const char *path, void *opts)
2057 {
2058         return mount_single (t, flags, opts, gadgetfs_fill_super);
2059 }
2060
2061 static void
2062 gadgetfs_kill_sb (struct super_block *sb)
2063 {
2064         kill_litter_super (sb);
2065         if (the_device) {
2066                 put_dev (the_device);
2067                 the_device = NULL;
2068         }
2069         kfree(CHIP);
2070         CHIP = NULL;
2071 }
2072
2073 /*----------------------------------------------------------------------*/
2074
2075 static struct file_system_type gadgetfs_type = {
2076         .owner          = THIS_MODULE,
2077         .name           = shortname,
2078         .mount          = gadgetfs_mount,
2079         .kill_sb        = gadgetfs_kill_sb,
2080 };
2081 MODULE_ALIAS_FS("gadgetfs");
2082
2083 /*----------------------------------------------------------------------*/
2084
2085 static int __init init (void)
2086 {
2087         int status;
2088
2089         status = register_filesystem (&gadgetfs_type);
2090         if (status == 0)
2091                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2092                         shortname, driver_desc);
2093         return status;
2094 }
2095 module_init (init);
2096
2097 static void __exit cleanup (void)
2098 {
2099         pr_debug ("unregister %s\n", shortname);
2100         unregister_filesystem (&gadgetfs_type);
2101 }
2102 module_exit (cleanup);
2103