drivers/usb/gadget/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 <asm/uaccess.h>
  24 #include <linux/sched.h>
  25 #include <linux/slab.h>
  26 #include <linux/poll.h>
  27
  28 #include <linux/device.h>
  29 #include <linux/moduleparam.h>
  30
  31 #include <linux/usb/gadgetfs.h>
  32 #include <linux/usb/gadget.h>
  33
  34
  35 /*
  36  * The gadgetfs API maps each endpoint to a file descriptor so that you
  37  * can use standard synchronous read/write calls for I/O.  There's some
  38  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  39  * drivers show how this works in practice.  You can also use AIO to
  40  * eliminate I/O gaps between requests, to help when streaming data.
  41  *
  42  * Key parts that must be USB-specific are protocols defining how the
  43  * read/write operations relate to the hardware state machines.  There
  44  * are two types of files.  One type is for the device, implementing ep0.
  45  * The other type is for each IN or OUT endpoint.  In both cases, the
  46  * user mode driver must configure the hardware before using it.
  47  *
  48  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  49  *   (by writing configuration and device descriptors).  Afterwards it
  50  *   may serve as a source of device events, used to handle all control
  51  *   requests other than basic enumeration.
  52  *
  53  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  54  *   called when each /dev/gadget/ep* file is configured (by writing
  55  *   endpoint descriptors).  Afterwards these files are used to write()
  56  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  57  *   direction" request is issued (like reading an IN endpoint).
  58  *
  59  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  60  * not possible on all hardware.  For example, precise fault handling with
  61  * respect to data left in endpoint fifos after aborted operations; or
  62  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  63  */
  64
  65 #define DRIVER_DESC     "USB Gadget filesystem"
  66 #define DRIVER_VERSION  "24 Aug 2004"
  67
  68 static const char driver_desc [] = DRIVER_DESC;
  69 static const char shortname [] = "gadgetfs";
  70
  71 MODULE_DESCRIPTION (DRIVER_DESC);
  72 MODULE_AUTHOR ("David Brownell");
  73 MODULE_LICENSE ("GPL");
  74
  75
  76 /*----------------------------------------------------------------------*/
  77
  78 #define GADGETFS_MAGIC          0xaee71ee7
  79
  80 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  81 enum ep0_state {
  82         /* DISBLED is the initial state.
  83          */
  84         STATE_DEV_DISABLED = 0,
  85
  86         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  87          * ep0/device i/o modes and binding to the controller.  Driver
  88          * must always write descriptors to initialize the device, then
  89          * the device becomes UNCONNECTED until enumeration.
  90          */
  91         STATE_DEV_OPENED,
  92
  93         /* From then on, ep0 fd is in either of two basic modes:
  94          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
  95          * - SETUP: read/write will transfer control data and succeed;
  96          *   or if "wrong direction", performs protocol stall
  97          */
  98         STATE_DEV_UNCONNECTED,
  99         STATE_DEV_CONNECTED,
 100         STATE_DEV_SETUP,
 101
 102         /* UNBOUND means the driver closed ep0, so the device won't be
 103          * accessible again (DEV_DISABLED) until all fds are closed.
 104          */
 105         STATE_DEV_UNBOUND,
 106 };
 107
 108 /* enough for the whole queue: most events invalidate others */
 109 #define N_EVENT                 5
 110
 111 struct dev_data {
 112         spinlock_t                      lock;
 113         atomic_t                        count;
 114         enum ep0_state                  state;          /* P: lock */
 115         struct usb_gadgetfs_event       event [N_EVENT];
 116         unsigned                        ev_next;
 117         struct fasync_struct            *fasync;
 118         u8                              current_config;
 119
 120         /* drivers reading ep0 MUST handle control requests (SETUP)
 121          * reported that way; else the host will time out.
 122          */
 123         unsigned                        usermode_setup : 1,
 124                                         setup_in : 1,
 125                                         setup_can_stall : 1,
 126                                         setup_out_ready : 1,
 127                                         setup_out_error : 1,
 128                                         setup_abort : 1;
 129         unsigned                        setup_wLength;
 130
 131         /* the rest is basically write-once */
 132         struct usb_config_descriptor    *config, *hs_config;
 133         struct usb_device_descriptor    *dev;
 134         struct usb_request              *req;
 135         struct usb_gadget               *gadget;
 136         struct list_head                epfiles;
 137         void                            *buf;
 138         wait_queue_head_t               wait;
 139         struct super_block              *sb;
 140         struct dentry                   *dentry;
 141
 142         /* except this scratch i/o buffer for ep0 */
 143         u8                              rbuf [256];
 144 };
 145
 146 static inline void get_dev (struct dev_data *data)
 147 {
 148         atomic_inc (&data->count);
 149 }
 150
 151 static void put_dev (struct dev_data *data)
 152 {
 153         if (likely (!atomic_dec_and_test (&data->count)))
 154                 return;
 155         /* needs no more cleanup */
 156         BUG_ON (waitqueue_active (&data->wait));
 157         kfree (data);
 158 }
 159
 160 static struct dev_data *dev_new (void)
 161 {
 162         struct dev_data         *dev;
 163
 164         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 165         if (!dev)
 166                 return NULL;
 167         dev->state = STATE_DEV_DISABLED;
 168         atomic_set (&dev->count, 1);
 169         spin_lock_init (&dev->lock);
 170         INIT_LIST_HEAD (&dev->epfiles);
 171         init_waitqueue_head (&dev->wait);
 172         return dev;
 173 }
 174
 175 /*----------------------------------------------------------------------*/
 176
 177 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 178 enum ep_state {
 179         STATE_EP_DISABLED = 0,
 180         STATE_EP_READY,
 181         STATE_EP_ENABLED,
 182         STATE_EP_UNBOUND,
 183 };
 184
 185 struct ep_data {
 186         struct mutex                    lock;
 187         enum ep_state                   state;
 188         atomic_t                        count;
 189         struct dev_data                 *dev;
 190         /* must hold dev->lock before accessing ep or req */
 191         struct usb_ep                   *ep;
 192         struct usb_request              *req;
 193         ssize_t                         status;
 194         char                            name [16];
 195         struct usb_endpoint_descriptor  desc, hs_desc;
 196         struct list_head                epfiles;
 197         wait_queue_head_t               wait;
 198         struct dentry                   *dentry;
 199         struct inode                    *inode;
 200 };
 201
 202 static inline void get_ep (struct ep_data *data)
 203 {
 204         atomic_inc (&data->count);
 205 }
 206
 207 static void put_ep (struct ep_data *data)
 208 {
 209         if (likely (!atomic_dec_and_test (&data->count)))
 210                 return;
 211         put_dev (data->dev);
 212         /* needs no more cleanup */
 213         BUG_ON (!list_empty (&data->epfiles));
 214         BUG_ON (waitqueue_active (&data->wait));
 215         kfree (data);
 216 }
 217
 218 /*----------------------------------------------------------------------*/
 219
 220 /* most "how to use the hardware" policy choices are in userspace:
 221  * mapping endpoint roles (which the driver needs) to the capabilities
 222  * which the usb controller has.  most of those capabilities are exposed
 223  * implicitly, starting with the driver name and then endpoint names.
 224  */
 225
 226 static const char *CHIP;
 227
 228 /*----------------------------------------------------------------------*/
 229
 230 /* NOTE:  don't use dev_printk calls before binding to the gadget
 231  * at the end of ep0 configuration, or after unbind.
 232  */
 233
 234 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 235 #define xprintk(d,level,fmt,args...) \
 236         printk(level "%s: " fmt , shortname , ## args)
 237
 238 #ifdef DEBUG
 239 #define DBG(dev,fmt,args...) \
 240         xprintk(dev , KERN_DEBUG , fmt , ## args)
 241 #else
 242 #define DBG(dev,fmt,args...) \
 243         do { } while (0)
 244 #endif /* DEBUG */
 245
 246 #ifdef VERBOSE_DEBUG
 247 #define VDEBUG  DBG
 248 #else
 249 #define VDEBUG(dev,fmt,args...) \
 250         do { } while (0)
 251 #endif /* DEBUG */
 252
 253 #define ERROR(dev,fmt,args...) \
 254         xprintk(dev , KERN_ERR , fmt , ## args)
 255 #define INFO(dev,fmt,args...) \
 256         xprintk(dev , KERN_INFO , fmt , ## args)
 257
 258
 259 /*----------------------------------------------------------------------*/
 260
 261 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 262  *
 263  * After opening, configure non-control endpoints.  Then use normal
 264  * stream read() and write() requests; and maybe ioctl() to get more
 265  * precise FIFO status when recovering from cancellation.
 266  */
 267
 268 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 269 {
 270         struct ep_data  *epdata = ep->driver_data;
 271
 272         if (!req->context)
 273                 return;
 274         if (req->status)
 275                 epdata->status = req->status;
 276         else
 277                 epdata->status = req->actual;
 278         complete ((struct completion *)req->context);
 279 }
 280
 281 /* tasklock endpoint, returning when it's connected.
 282  * still need dev->lock to use epdata->ep.
 283  */
 284 static int
 285 get_ready_ep (unsigned f_flags, struct ep_data *epdata)
 286 {
 287         int     val;
 288
 289         if (f_flags & O_NONBLOCK) {
 290                 if (!mutex_trylock(&epdata->lock))
 291                         goto nonblock;
 292                 if (epdata->state != STATE_EP_ENABLED) {
 293                         mutex_unlock(&epdata->lock);
 294 nonblock:
 295                         val = -EAGAIN;
 296                 } else
 297                         val = 0;
 298                 return val;
 299         }
 300
 301         val = mutex_lock_interruptible(&epdata->lock);
 302         if (val < 0)
 303                 return val;
 304
 305         switch (epdata->state) {
 306         case STATE_EP_ENABLED:
 307                 break;
 308         // case STATE_EP_DISABLED:              /* "can't happen" */
 309         // case STATE_EP_READY:                 /* "can't happen" */
 310         default:                                /* error! */
 311                 pr_debug ("%s: ep %p not available, state %d\n",
 312                                 shortname, epdata, epdata->state);
 313                 // FALLTHROUGH
 314         case STATE_EP_UNBOUND:                  /* clean disconnect */
 315                 val = -ENODEV;
 316                 mutex_unlock(&epdata->lock);
 317         }
 318         return val;
 319 }
 320
 321 static ssize_t
 322 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 323 {
 324         DECLARE_COMPLETION_ONSTACK (done);
 325         int value;
 326
 327         spin_lock_irq (&epdata->dev->lock);
 328         if (likely (epdata->ep != NULL)) {
 329                 struct usb_request      *req = epdata->req;
 330
 331                 req->context = &done;
 332                 req->complete = epio_complete;
 333                 req->buf = buf;
 334                 req->length = len;
 335                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 336         } else
 337                 value = -ENODEV;
 338         spin_unlock_irq (&epdata->dev->lock);
 339
 340         if (likely (value == 0)) {
 341                 value = wait_event_interruptible (done.wait, done.done);
 342                 if (value != 0) {
 343                         spin_lock_irq (&epdata->dev->lock);
 344                         if (likely (epdata->ep != NULL)) {
 345                                 DBG (epdata->dev, "%s i/o interrupted\n",
 346                                                 epdata->name);
 347                                 usb_ep_dequeue (epdata->ep, epdata->req);
 348                                 spin_unlock_irq (&epdata->dev->lock);
 349
 350                                 wait_event (done.wait, done.done);
 351                                 if (epdata->status == -ECONNRESET)
 352                                         epdata->status = -EINTR;
 353                         } else {
 354                                 spin_unlock_irq (&epdata->dev->lock);
 355
 356                                 DBG (epdata->dev, "endpoint gone\n");
 357                                 epdata->status = -ENODEV;
 358                         }
 359                 }
 360                 return epdata->status;
 361         }
 362         return value;
 363 }
 364
 365
 366 /* handle a synchronous OUT bulk/intr/iso transfer */
 367 static ssize_t
 368 ep_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 369 {
 370         struct ep_data          *data = fd->private_data;
 371         void                    *kbuf;
 372         ssize_t                 value;
 373
 374         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
 375                 return value;
 376
 377         /* halt any endpoint by doing a "wrong direction" i/o call */
 378         if (usb_endpoint_dir_in(&data->desc)) {
 379                 if (usb_endpoint_xfer_isoc(&data->desc)) {
 380                         mutex_unlock(&data->lock);
 381                         return -EINVAL;
 382                 }
 383                 DBG (data->dev, "%s halt\n", data->name);
 384                 spin_lock_irq (&data->dev->lock);
 385                 if (likely (data->ep != NULL))
 386                         usb_ep_set_halt (data->ep);
 387                 spin_unlock_irq (&data->dev->lock);
 388                 mutex_unlock(&data->lock);
 389                 return -EBADMSG;
 390         }
 391
 392         /* FIXME readahead for O_NONBLOCK and poll(); careful with ZLPs */
 393
 394         value = -ENOMEM;
 395         kbuf = kmalloc (len, GFP_KERNEL);
 396         if (unlikely (!kbuf))
 397                 goto free1;
 398
 399         value = ep_io (data, kbuf, len);
 400         VDEBUG (data->dev, "%s read %zu OUT, status %d\n",
 401                 data->name, len, (int) value);
 402         if (value >= 0 && copy_to_user (buf, kbuf, value))
 403                 value = -EFAULT;
 404
 405 free1:
 406         mutex_unlock(&data->lock);
 407         kfree (kbuf);
 408         return value;
 409 }
 410
 411 /* handle a synchronous IN bulk/intr/iso transfer */
 412 static ssize_t
 413 ep_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 414 {
 415         struct ep_data          *data = fd->private_data;
 416         void                    *kbuf;
 417         ssize_t                 value;
 418
 419         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
 420                 return value;
 421
 422         /* halt any endpoint by doing a "wrong direction" i/o call */
 423         if (!usb_endpoint_dir_in(&data->desc)) {
 424                 if (usb_endpoint_xfer_isoc(&data->desc)) {
 425                         mutex_unlock(&data->lock);
 426                         return -EINVAL;
 427                 }
 428                 DBG (data->dev, "%s halt\n", data->name);
 429                 spin_lock_irq (&data->dev->lock);
 430                 if (likely (data->ep != NULL))
 431                         usb_ep_set_halt (data->ep);
 432                 spin_unlock_irq (&data->dev->lock);
 433                 mutex_unlock(&data->lock);
 434                 return -EBADMSG;
 435         }
 436
 437         /* FIXME writebehind for O_NONBLOCK and poll(), qlen = 1 */
 438
 439         value = -ENOMEM;
 440         kbuf = kmalloc (len, GFP_KERNEL);
 441         if (!kbuf)
 442                 goto free1;
 443         if (copy_from_user (kbuf, buf, len)) {
 444                 value = -EFAULT;
 445                 goto free1;
 446         }
 447
 448         value = ep_io (data, kbuf, len);
 449         VDEBUG (data->dev, "%s write %zu IN, status %d\n",
 450                 data->name, len, (int) value);
 451 free1:
 452         mutex_unlock(&data->lock);
 453         kfree (kbuf);
 454         return value;
 455 }
 456
 457 static int
 458 ep_release (struct inode *inode, struct file *fd)
 459 {
 460         struct ep_data          *data = fd->private_data;
 461         int value;
 462
 463         value = mutex_lock_interruptible(&data->lock);
 464         if (value < 0)
 465                 return value;
 466
 467         /* clean up if this can be reopened */
 468         if (data->state != STATE_EP_UNBOUND) {
 469                 data->state = STATE_EP_DISABLED;
 470                 data->desc.bDescriptorType = 0;
 471                 data->hs_desc.bDescriptorType = 0;
 472                 usb_ep_disable(data->ep);
 473         }
 474         mutex_unlock(&data->lock);
 475         put_ep (data);
 476         return 0;
 477 }
 478
 479 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 480 {
 481         struct ep_data          *data = fd->private_data;
 482         int                     status;
 483
 484         if ((status = get_ready_ep (fd->f_flags, data)) < 0)
 485                 return status;
 486
 487         spin_lock_irq (&data->dev->lock);
 488         if (likely (data->ep != NULL)) {
 489                 switch (code) {
 490                 case GADGETFS_FIFO_STATUS:
 491                         status = usb_ep_fifo_status (data->ep);
 492                         break;
 493                 case GADGETFS_FIFO_FLUSH:
 494                         usb_ep_fifo_flush (data->ep);
 495                         break;
 496                 case GADGETFS_CLEAR_HALT:
 497                         status = usb_ep_clear_halt (data->ep);
 498                         break;
 499                 default:
 500                         status = -ENOTTY;
 501                 }
 502         } else
 503                 status = -ENODEV;
 504         spin_unlock_irq (&data->dev->lock);
 505         mutex_unlock(&data->lock);
 506         return status;
 507 }
 508
 509 /*----------------------------------------------------------------------*/
 510
 511 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 512
 513 struct kiocb_priv {
 514         struct usb_request      *req;
 515         struct ep_data          *epdata;
 516         void                    *buf;
 517         const struct iovec      *iv;
 518         unsigned long           nr_segs;
 519         unsigned                actual;
 520 };
 521
 522 static int ep_aio_cancel(struct kiocb *iocb, struct io_event *e)
 523 {
 524         struct kiocb_priv       *priv = iocb->private;
 525         struct ep_data          *epdata;
 526         int                     value;
 527
 528         local_irq_disable();
 529         epdata = priv->epdata;
 530         // spin_lock(&epdata->dev->lock);
 531         kiocbSetCancelled(iocb);
 532         if (likely(epdata && epdata->ep && priv->req))
 533                 value = usb_ep_dequeue (epdata->ep, priv->req);
 534         else
 535                 value = -EINVAL;
 536         // spin_unlock(&epdata->dev->lock);
 537         local_irq_enable();
 538
 539         aio_put_req(iocb);
 540         return value;
 541 }
 542
 543 static ssize_t ep_aio_read_retry(struct kiocb *iocb)
 544 {
 545         struct kiocb_priv       *priv = iocb->private;
 546         ssize_t                 len, total;
 547         void                    *to_copy;
 548         int                     i;
 549
 550         /* we "retry" to get the right mm context for this: */
 551
 552         /* copy stuff into user buffers */
 553         total = priv->actual;
 554         len = 0;
 555         to_copy = priv->buf;
 556         for (i=0; i < priv->nr_segs; i++) {
 557                 ssize_t this = min((ssize_t)(priv->iv[i].iov_len), total);
 558
 559                 if (copy_to_user(priv->iv[i].iov_base, to_copy, this)) {
 560                         if (len == 0)
 561                                 len = -EFAULT;
 562                         break;
 563                 }
 564
 565                 total -= this;
 566                 len += this;
 567                 to_copy += this;
 568                 if (total == 0)
 569                         break;
 570         }
 571         kfree(priv->buf);
 572         kfree(priv);
 573         return len;
 574 }
 575
 576 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 577 {
 578         struct kiocb            *iocb = req->context;
 579         struct kiocb_priv       *priv = iocb->private;
 580         struct ep_data          *epdata = priv->epdata;
 581
 582         /* lock against disconnect (and ideally, cancel) */
 583         spin_lock(&epdata->dev->lock);
 584         priv->req = NULL;
 585         priv->epdata = NULL;
 586
 587         /* if this was a write or a read returning no data then we
 588          * don't need to copy anything to userspace, so we can
 589          * complete the aio request immediately.
 590          */
 591         if (priv->iv == NULL || unlikely(req->actual == 0)) {
 592                 kfree(req->buf);
 593                 kfree(priv);
 594                 iocb->private = NULL;
 595                 /* aio_complete() reports bytes-transferred _and_ faults */
 596                 aio_complete(iocb, req->actual ? req->actual : req->status,
 597                                 req->status);
 598         } else {
 599                 /* retry() won't report both; so we hide some faults */
 600                 if (unlikely(0 != req->status))
 601                         DBG(epdata->dev, "%s fault %d len %d\n",
 602                                 ep->name, req->status, req->actual);
 603
 604                 priv->buf = req->buf;
 605                 priv->actual = req->actual;
 606                 kick_iocb(iocb);
 607         }
 608         spin_unlock(&epdata->dev->lock);
 609
 610         usb_ep_free_request(ep, req);
 611         put_ep(epdata);
 612 }
 613
 614 static ssize_t
 615 ep_aio_rwtail(
 616         struct kiocb    *iocb,
 617         char            *buf,
 618         size_t          len,
 619         struct ep_data  *epdata,
 620         const struct iovec *iv,
 621         unsigned long   nr_segs
 622 )
 623 {
 624         struct kiocb_priv       *priv;
 625         struct usb_request      *req;
 626         ssize_t                 value;
 627
 628         priv = kmalloc(sizeof *priv, GFP_KERNEL);
 629         if (!priv) {
 630                 value = -ENOMEM;
 631 fail:
 632                 kfree(buf);
 633                 return value;
 634         }
 635         iocb->private = priv;
 636         priv->iv = iv;
 637         priv->nr_segs = nr_segs;
 638
 639         value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
 640         if (unlikely(value < 0)) {
 641                 kfree(priv);
 642                 goto fail;
 643         }
 644
 645         iocb->ki_cancel = ep_aio_cancel;
 646         get_ep(epdata);
 647         priv->epdata = epdata;
 648         priv->actual = 0;
 649
 650         /* each kiocb is coupled to one usb_request, but we can't
 651          * allocate or submit those if the host disconnected.
 652          */
 653         spin_lock_irq(&epdata->dev->lock);
 654         if (likely(epdata->ep)) {
 655                 req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 656                 if (likely(req)) {
 657                         priv->req = req;
 658                         req->buf = buf;
 659                         req->length = len;
 660                         req->complete = ep_aio_complete;
 661                         req->context = iocb;
 662                         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 663                         if (unlikely(0 != value))
 664                                 usb_ep_free_request(epdata->ep, req);
 665                 } else
 666                         value = -EAGAIN;
 667         } else
 668                 value = -ENODEV;
 669         spin_unlock_irq(&epdata->dev->lock);
 670
 671         mutex_unlock(&epdata->lock);
 672
 673         if (unlikely(value)) {
 674                 kfree(priv);
 675                 put_ep(epdata);
 676         } else
 677                 value = (iv ? -EIOCBRETRY : -EIOCBQUEUED);
 678         return value;
 679 }
 680
 681 static ssize_t
 682 ep_aio_read(struct kiocb *iocb, const struct iovec *iov,
 683                 unsigned long nr_segs, loff_t o)
 684 {
 685         struct ep_data          *epdata = iocb->ki_filp->private_data;
 686         char                    *buf;
 687
 688         if (unlikely(usb_endpoint_dir_in(&epdata->desc)))
 689                 return -EINVAL;
 690
 691         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 692         if (unlikely(!buf))
 693                 return -ENOMEM;
 694
 695         iocb->ki_retry = ep_aio_read_retry;
 696         return ep_aio_rwtail(iocb, buf, iocb->ki_left, epdata, iov, nr_segs);
 697 }
 698
 699 static ssize_t
 700 ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
 701                 unsigned long nr_segs, loff_t o)
 702 {
 703         struct ep_data          *epdata = iocb->ki_filp->private_data;
 704         char                    *buf;
 705         size_t                  len = 0;
 706         int                     i = 0;
 707
 708         if (unlikely(!usb_endpoint_dir_in(&epdata->desc)))
 709                 return -EINVAL;
 710
 711         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 712         if (unlikely(!buf))
 713                 return -ENOMEM;
 714
 715         for (i=0; i < nr_segs; i++) {
 716                 if (unlikely(copy_from_user(&buf[len], iov[i].iov_base,
 717                                 iov[i].iov_len) != 0)) {
 718                         kfree(buf);
 719                         return -EFAULT;
 720                 }
 721                 len += iov[i].iov_len;
 722         }
 723         return ep_aio_rwtail(iocb, buf, len, epdata, NULL, 0);
 724 }
 725
 726 /*----------------------------------------------------------------------*/
 727
 728 /* used after endpoint configuration */
 729 static const struct file_operations ep_io_operations = {
 730         .owner =        THIS_MODULE,
 731         .llseek =       no_llseek,
 732
 733         .read =         ep_read,
 734         .write =        ep_write,
 735         .unlocked_ioctl = ep_ioctl,
 736         .release =      ep_release,
 737
 738         .aio_read =     ep_aio_read,
 739         .aio_write =    ep_aio_write,
 740 };
 741
 742 /* ENDPOINT INITIALIZATION
 743  *
 744  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 745  *     status = write (fd, descriptors, sizeof descriptors)
 746  *
 747  * That write establishes the endpoint configuration, configuring
 748  * the controller to process bulk, interrupt, or isochronous transfers
 749  * at the right maxpacket size, and so on.
 750  *
 751  * The descriptors are message type 1, identified by a host order u32
 752  * at the beginning of what's written.  Descriptor order is: full/low
 753  * speed descriptor, then optional high speed descriptor.
 754  */
 755 static ssize_t
 756 ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 757 {
 758         struct ep_data          *data = fd->private_data;
 759         struct usb_ep           *ep;
 760         u32                     tag;
 761         int                     value, length = len;
 762
 763         value = mutex_lock_interruptible(&data->lock);
 764         if (value < 0)
 765                 return value;
 766
 767         if (data->state != STATE_EP_READY) {
 768                 value = -EL2HLT;
 769                 goto fail;
 770         }
 771
 772         value = len;
 773         if (len < USB_DT_ENDPOINT_SIZE + 4)
 774                 goto fail0;
 775
 776         /* we might need to change message format someday */
 777         if (copy_from_user (&tag, buf, 4)) {
 778                 goto fail1;
 779         }
 780         if (tag != 1) {
 781                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 782                 goto fail0;
 783         }
 784         buf += 4;
 785         len -= 4;
 786
 787         /* NOTE:  audio endpoint extensions not accepted here;
 788          * just don't include the extra bytes.
 789          */
 790
 791         /* full/low speed descriptor, then high speed */
 792         if (copy_from_user (&data->desc, buf, USB_DT_ENDPOINT_SIZE)) {
 793                 goto fail1;
 794         }
 795         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 796                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 797                 goto fail0;
 798         if (len != USB_DT_ENDPOINT_SIZE) {
 799                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 800                         goto fail0;
 801                 if (copy_from_user (&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 802                                         USB_DT_ENDPOINT_SIZE)) {
 803                         goto fail1;
 804                 }
 805                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 806                                 || data->hs_desc.bDescriptorType
 807                                         != USB_DT_ENDPOINT) {
 808                         DBG(data->dev, "config %s, bad hs length or type\n",
 809                                         data->name);
 810                         goto fail0;
 811                 }
 812         }
 813
 814         spin_lock_irq (&data->dev->lock);
 815         if (data->dev->state == STATE_DEV_UNBOUND) {
 816                 value = -ENOENT;
 817                 goto gone;
 818         } else if ((ep = data->ep) == NULL) {
 819                 value = -ENODEV;
 820                 goto gone;
 821         }
 822         switch (data->dev->gadget->speed) {
 823         case USB_SPEED_LOW:
 824         case USB_SPEED_FULL:
 825                 ep->desc = &data->desc;
 826                 value = usb_ep_enable(ep);
 827                 if (value == 0)
 828                         data->state = STATE_EP_ENABLED;
 829                 break;
 830         case USB_SPEED_HIGH:
 831                 /* fails if caller didn't provide that descriptor... */
 832                 ep->desc = &data->hs_desc;
 833                 value = usb_ep_enable(ep);
 834                 if (value == 0)
 835                         data->state = STATE_EP_ENABLED;
 836                 break;
 837         default:
 838                 DBG(data->dev, "unconnected, %s init abandoned\n",
 839                                 data->name);
 840                 value = -EINVAL;
 841         }
 842         if (value == 0) {
 843                 fd->f_op = &ep_io_operations;
 844                 value = length;
 845         }
 846 gone:
 847         spin_unlock_irq (&data->dev->lock);
 848         if (value < 0) {
 849 fail:
 850                 data->desc.bDescriptorType = 0;
 851                 data->hs_desc.bDescriptorType = 0;
 852         }
 853         mutex_unlock(&data->lock);
 854         return value;
 855 fail0:
 856         value = -EINVAL;
 857         goto fail;
 858 fail1:
 859         value = -EFAULT;
 860         goto fail;
 861 }
 862
 863 static int
 864 ep_open (struct inode *inode, struct file *fd)
 865 {
 866         struct ep_data          *data = inode->i_private;
 867         int                     value = -EBUSY;
 868
 869         if (mutex_lock_interruptible(&data->lock) != 0)
 870                 return -EINTR;
 871         spin_lock_irq (&data->dev->lock);
 872         if (data->dev->state == STATE_DEV_UNBOUND)
 873                 value = -ENOENT;
 874         else if (data->state == STATE_EP_DISABLED) {
 875                 value = 0;
 876                 data->state = STATE_EP_READY;
 877                 get_ep (data);
 878                 fd->private_data = data;
 879                 VDEBUG (data->dev, "%s ready\n", data->name);
 880         } else
 881                 DBG (data->dev, "%s state %d\n",
 882                         data->name, data->state);
 883         spin_unlock_irq (&data->dev->lock);
 884         mutex_unlock(&data->lock);
 885         return value;
 886 }
 887
 888 /* used before endpoint configuration */
 889 static const struct file_operations ep_config_operations = {
 890         .llseek =       no_llseek,
 891
 892         .open =         ep_open,
 893         .write =        ep_config,
 894         .release =      ep_release,
 895 };
 896
 897 /*----------------------------------------------------------------------*/
 898
 899 /* EP0 IMPLEMENTATION can be partly in userspace.
 900  *
 901  * Drivers that use this facility receive various events, including
 902  * control requests the kernel doesn't handle.  Drivers that don't
 903  * use this facility may be too simple-minded for real applications.
 904  */
 905
 906 static inline void ep0_readable (struct dev_data *dev)
 907 {
 908         wake_up (&dev->wait);
 909         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 910 }
 911
 912 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 913 {
 914         struct dev_data         *dev = ep->driver_data;
 915
 916         if (req->buf != dev->rbuf) {
 917                 kfree(req->buf);
 918                 req->buf = dev->rbuf;
 919         }
 920         req->complete = epio_complete;
 921         dev->setup_out_ready = 0;
 922 }
 923
 924 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 925 {
 926         struct dev_data         *dev = ep->driver_data;
 927         unsigned long           flags;
 928         int                     free = 1;
 929
 930         /* for control OUT, data must still get to userspace */
 931         spin_lock_irqsave(&dev->lock, flags);
 932         if (!dev->setup_in) {
 933                 dev->setup_out_error = (req->status != 0);
 934                 if (!dev->setup_out_error)
 935                         free = 0;
 936                 dev->setup_out_ready = 1;
 937                 ep0_readable (dev);
 938         }
 939
 940         /* clean up as appropriate */
 941         if (free && req->buf != &dev->rbuf)
 942                 clean_req (ep, req);
 943         req->complete = epio_complete;
 944         spin_unlock_irqrestore(&dev->lock, flags);
 945 }
 946
 947 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 948 {
 949         struct dev_data *dev = ep->driver_data;
 950
 951         if (dev->setup_out_ready) {
 952                 DBG (dev, "ep0 request busy!\n");
 953                 return -EBUSY;
 954         }
 955         if (len > sizeof (dev->rbuf))
 956                 req->buf = kmalloc(len, GFP_ATOMIC);
 957         if (req->buf == NULL) {
 958                 req->buf = dev->rbuf;
 959                 return -ENOMEM;
 960         }
 961         req->complete = ep0_complete;
 962         req->length = len;
 963         req->zero = 0;
 964         return 0;
 965 }
 966
 967 static ssize_t
 968 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 969 {
 970         struct dev_data                 *dev = fd->private_data;
 971         ssize_t                         retval;
 972         enum ep0_state                  state;
 973
 974         spin_lock_irq (&dev->lock);
 975
 976         /* report fd mode change before acting on it */
 977         if (dev->setup_abort) {
 978                 dev->setup_abort = 0;
 979                 retval = -EIDRM;
 980                 goto done;
 981         }
 982
 983         /* control DATA stage */
 984         if ((state = dev->state) == STATE_DEV_SETUP) {
 985
 986                 if (dev->setup_in) {            /* stall IN */
 987                         VDEBUG(dev, "ep0in stall\n");
 988                         (void) usb_ep_set_halt (dev->gadget->ep0);
 989                         retval = -EL2HLT;
 990                         dev->state = STATE_DEV_CONNECTED;
 991
 992                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
 993                         struct usb_ep           *ep = dev->gadget->ep0;
 994                         struct usb_request      *req = dev->req;
 995
 996                         if ((retval = setup_req (ep, req, 0)) == 0)
 997                                 retval = usb_ep_queue (ep, req, GFP_ATOMIC);
 998                         dev->state = STATE_DEV_CONNECTED;
 999
1000                         /* assume that was SET_CONFIGURATION */
1001                         if (dev->current_config) {
1002                                 unsigned power;
1003
1004                                 if (gadget_is_dualspeed(dev->gadget)
1005                                                 && (dev->gadget->speed
1006                                                         == USB_SPEED_HIGH))
1007                                         power = dev->hs_config->bMaxPower;
1008                                 else
1009                                         power = dev->config->bMaxPower;
1010                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
1011                         }
1012
1013                 } else {                        /* collect OUT data */
1014                         if ((fd->f_flags & O_NONBLOCK) != 0
1015                                         && !dev->setup_out_ready) {
1016                                 retval = -EAGAIN;
1017                                 goto done;
1018                         }
1019                         spin_unlock_irq (&dev->lock);
1020                         retval = wait_event_interruptible (dev->wait,
1021                                         dev->setup_out_ready != 0);
1022
1023                         /* FIXME state could change from under us */
1024                         spin_lock_irq (&dev->lock);
1025                         if (retval)
1026                                 goto done;
1027
1028                         if (dev->state != STATE_DEV_SETUP) {
1029                                 retval = -ECANCELED;
1030                                 goto done;
1031                         }
1032                         dev->state = STATE_DEV_CONNECTED;
1033
1034                         if (dev->setup_out_error)
1035                                 retval = -EIO;
1036                         else {
1037                                 len = min (len, (size_t)dev->req->actual);
1038 // FIXME don't call this with the spinlock held ...
1039                                 if (copy_to_user (buf, dev->req->buf, len))
1040                                         retval = -EFAULT;
1041                                 else
1042                                         retval = len;
1043                                 clean_req (dev->gadget->ep0, dev->req);
1044                                 /* NOTE userspace can't yet choose to stall */
1045                         }
1046                 }
1047                 goto done;
1048         }
1049
1050         /* else normal: return event data */
1051         if (len < sizeof dev->event [0]) {
1052                 retval = -EINVAL;
1053                 goto done;
1054         }
1055         len -= len % sizeof (struct usb_gadgetfs_event);
1056         dev->usermode_setup = 1;
1057
1058 scan:
1059         /* return queued events right away */
1060         if (dev->ev_next != 0) {
1061                 unsigned                i, n;
1062
1063                 n = len / sizeof (struct usb_gadgetfs_event);
1064                 if (dev->ev_next < n)
1065                         n = dev->ev_next;
1066
1067                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1068                 for (i = 0; i < n; i++) {
1069                         if (dev->event [i].type == GADGETFS_SETUP) {
1070                                 dev->state = STATE_DEV_SETUP;
1071                                 n = i + 1;
1072                                 break;
1073                         }
1074                 }
1075                 spin_unlock_irq (&dev->lock);
1076                 len = n * sizeof (struct usb_gadgetfs_event);
1077                 if (copy_to_user (buf, &dev->event, len))
1078                         retval = -EFAULT;
1079                 else
1080                         retval = len;
1081                 if (len > 0) {
1082                         /* NOTE this doesn't guard against broken drivers;
1083                          * concurrent ep0 readers may lose events.
1084                          */
1085                         spin_lock_irq (&dev->lock);
1086                         if (dev->ev_next > n) {
1087                                 memmove(&dev->event[0], &dev->event[n],
1088                                         sizeof (struct usb_gadgetfs_event)
1089                                                 * (dev->ev_next - n));
1090                         }
1091                         dev->ev_next -= n;
1092                         spin_unlock_irq (&dev->lock);
1093                 }
1094                 return retval;
1095         }
1096         if (fd->f_flags & O_NONBLOCK) {
1097                 retval = -EAGAIN;
1098                 goto done;
1099         }
1100
1101         switch (state) {
1102         default:
1103                 DBG (dev, "fail %s, state %d\n", __func__, state);
1104                 retval = -ESRCH;
1105                 break;
1106         case STATE_DEV_UNCONNECTED:
1107         case STATE_DEV_CONNECTED:
1108                 spin_unlock_irq (&dev->lock);
1109                 DBG (dev, "%s wait\n", __func__);
1110
1111                 /* wait for events */
1112                 retval = wait_event_interruptible (dev->wait,
1113                                 dev->ev_next != 0);
1114                 if (retval < 0)
1115                         return retval;
1116                 spin_lock_irq (&dev->lock);
1117                 goto scan;
1118         }
1119
1120 done:
1121         spin_unlock_irq (&dev->lock);
1122         return retval;
1123 }
1124
1125 static struct usb_gadgetfs_event *
1126 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1127 {
1128         struct usb_gadgetfs_event       *event;
1129         unsigned                        i;
1130
1131         switch (type) {
1132         /* these events purge the queue */
1133         case GADGETFS_DISCONNECT:
1134                 if (dev->state == STATE_DEV_SETUP)
1135                         dev->setup_abort = 1;
1136                 // FALL THROUGH
1137         case GADGETFS_CONNECT:
1138                 dev->ev_next = 0;
1139                 break;
1140         case GADGETFS_SETUP:            /* previous request timed out */
1141         case GADGETFS_SUSPEND:          /* same effect */
1142                 /* these events can't be repeated */
1143                 for (i = 0; i != dev->ev_next; i++) {
1144                         if (dev->event [i].type != type)
1145                                 continue;
1146                         DBG(dev, "discard old event[%d] %d\n", i, type);
1147                         dev->ev_next--;
1148                         if (i == dev->ev_next)
1149                                 break;
1150                         /* indices start at zero, for simplicity */
1151                         memmove (&dev->event [i], &dev->event [i + 1],
1152                                 sizeof (struct usb_gadgetfs_event)
1153                                         * (dev->ev_next - i));
1154                 }
1155                 break;
1156         default:
1157                 BUG ();
1158         }
1159         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1160         event = &dev->event [dev->ev_next++];
1161         BUG_ON (dev->ev_next > N_EVENT);
1162         memset (event, 0, sizeof *event);
1163         event->type = type;
1164         return event;
1165 }
1166
1167 static ssize_t
1168 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1169 {
1170         struct dev_data         *dev = fd->private_data;
1171         ssize_t                 retval = -ESRCH;
1172
1173         spin_lock_irq (&dev->lock);
1174
1175         /* report fd mode change before acting on it */
1176         if (dev->setup_abort) {
1177                 dev->setup_abort = 0;
1178                 retval = -EIDRM;
1179
1180         /* data and/or status stage for control request */
1181         } else if (dev->state == STATE_DEV_SETUP) {
1182
1183                 /* IN DATA+STATUS caller makes len <= wLength */
1184                 if (dev->setup_in) {
1185                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1186                         if (retval == 0) {
1187                                 dev->state = STATE_DEV_CONNECTED;
1188                                 spin_unlock_irq (&dev->lock);
1189                                 if (copy_from_user (dev->req->buf, buf, len))
1190                                         retval = -EFAULT;
1191                                 else {
1192                                         if (len < dev->setup_wLength)
1193                                                 dev->req->zero = 1;
1194                                         retval = usb_ep_queue (
1195                                                 dev->gadget->ep0, dev->req,
1196                                                 GFP_KERNEL);
1197                                 }
1198                                 if (retval < 0) {
1199                                         spin_lock_irq (&dev->lock);
1200                                         clean_req (dev->gadget->ep0, dev->req);
1201                                         spin_unlock_irq (&dev->lock);
1202                                 } else
1203                                         retval = len;
1204
1205                                 return retval;
1206                         }
1207
1208                 /* can stall some OUT transfers */
1209                 } else if (dev->setup_can_stall) {
1210                         VDEBUG(dev, "ep0out stall\n");
1211                         (void) usb_ep_set_halt (dev->gadget->ep0);
1212                         retval = -EL2HLT;
1213                         dev->state = STATE_DEV_CONNECTED;
1214                 } else {
1215                         DBG(dev, "bogus ep0out stall!\n");
1216                 }
1217         } else
1218                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1219
1220         spin_unlock_irq (&dev->lock);
1221         return retval;
1222 }
1223
1224 static int
1225 ep0_fasync (int f, struct file *fd, int on)
1226 {
1227         struct dev_data         *dev = fd->private_data;
1228         // caller must F_SETOWN before signal delivery happens
1229         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1230         return fasync_helper (f, fd, on, &dev->fasync);
1231 }
1232
1233 static struct usb_gadget_driver gadgetfs_driver;
1234
1235 static int
1236 dev_release (struct inode *inode, struct file *fd)
1237 {
1238         struct dev_data         *dev = fd->private_data;
1239
1240         /* closing ep0 === shutdown all */
1241
1242         usb_gadget_unregister_driver (&gadgetfs_driver);
1243
1244         /* at this point "good" hardware has disconnected the
1245          * device from USB; the host won't see it any more.
1246          * alternatively, all host requests will time out.
1247          */
1248
1249         kfree (dev->buf);
1250         dev->buf = NULL;
1251         put_dev (dev);
1252
1253         /* other endpoints were all decoupled from this device */
1254         spin_lock_irq(&dev->lock);
1255         dev->state = STATE_DEV_DISABLED;
1256         spin_unlock_irq(&dev->lock);
1257         return 0;
1258 }
1259
1260 static unsigned int
1261 ep0_poll (struct file *fd, poll_table *wait)
1262 {
1263        struct dev_data         *dev = fd->private_data;
1264        int                     mask = 0;
1265
1266        poll_wait(fd, &dev->wait, wait);
1267
1268        spin_lock_irq (&dev->lock);
1269
1270        /* report fd mode change before acting on it */
1271        if (dev->setup_abort) {
1272                dev->setup_abort = 0;
1273                mask = POLLHUP;
1274                goto out;
1275        }
1276
1277        if (dev->state == STATE_DEV_SETUP) {
1278                if (dev->setup_in || dev->setup_can_stall)
1279                        mask = POLLOUT;
1280        } else {
1281                if (dev->ev_next != 0)
1282                        mask = POLLIN;
1283        }
1284 out:
1285        spin_unlock_irq(&dev->lock);
1286        return mask;
1287 }
1288
1289 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1290 {
1291         struct dev_data         *dev = fd->private_data;
1292         struct usb_gadget       *gadget = dev->gadget;
1293         long ret = -ENOTTY;
1294
1295         if (gadget->ops->ioctl)
1296                 ret = gadget->ops->ioctl (gadget, code, value);
1297
1298         return ret;
1299 }
1300
1301 /* used after device configuration */
1302 static const struct file_operations ep0_io_operations = {
1303         .owner =        THIS_MODULE,
1304         .llseek =       no_llseek,
1305
1306         .read =         ep0_read,
1307         .write =        ep0_write,
1308         .fasync =       ep0_fasync,
1309         .poll =         ep0_poll,
1310         .unlocked_ioctl =       dev_ioctl,
1311         .release =      dev_release,
1312 };
1313
1314 /*----------------------------------------------------------------------*/
1315
1316 /* The in-kernel gadget driver handles most ep0 issues, in particular
1317  * enumerating the single configuration (as provided from user space).
1318  *
1319  * Unrecognized ep0 requests may be handled in user space.
1320  */
1321
1322 static void make_qualifier (struct dev_data *dev)
1323 {
1324         struct usb_qualifier_descriptor         qual;
1325         struct usb_device_descriptor            *desc;
1326
1327         qual.bLength = sizeof qual;
1328         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1329         qual.bcdUSB = cpu_to_le16 (0x0200);
1330
1331         desc = dev->dev;
1332         qual.bDeviceClass = desc->bDeviceClass;
1333         qual.bDeviceSubClass = desc->bDeviceSubClass;
1334         qual.bDeviceProtocol = desc->bDeviceProtocol;
1335
1336         /* assumes ep0 uses the same value for both speeds ... */
1337         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1338
1339         qual.bNumConfigurations = 1;
1340         qual.bRESERVED = 0;
1341
1342         memcpy (dev->rbuf, &qual, sizeof qual);
1343 }
1344
1345 static int
1346 config_buf (struct dev_data *dev, u8 type, unsigned index)
1347 {
1348         int             len;
1349         int             hs = 0;
1350
1351         /* only one configuration */
1352         if (index > 0)
1353                 return -EINVAL;
1354
1355         if (gadget_is_dualspeed(dev->gadget)) {
1356                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1357                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1358                         hs = !hs;
1359         }
1360         if (hs) {
1361                 dev->req->buf = dev->hs_config;
1362                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1363         } else {
1364                 dev->req->buf = dev->config;
1365                 len = le16_to_cpu(dev->config->wTotalLength);
1366         }
1367         ((u8 *)dev->req->buf) [1] = type;
1368         return len;
1369 }
1370
1371 static int
1372 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1373 {
1374         struct dev_data                 *dev = get_gadget_data (gadget);
1375         struct usb_request              *req = dev->req;
1376         int                             value = -EOPNOTSUPP;
1377         struct usb_gadgetfs_event       *event;
1378         u16                             w_value = le16_to_cpu(ctrl->wValue);
1379         u16                             w_length = le16_to_cpu(ctrl->wLength);
1380
1381         spin_lock (&dev->lock);
1382         dev->setup_abort = 0;
1383         if (dev->state == STATE_DEV_UNCONNECTED) {
1384                 if (gadget_is_dualspeed(gadget)
1385                                 && gadget->speed == USB_SPEED_HIGH
1386                                 && dev->hs_config == NULL) {
1387                         spin_unlock(&dev->lock);
1388                         ERROR (dev, "no high speed config??\n");
1389                         return -EINVAL;
1390                 }
1391
1392                 dev->state = STATE_DEV_CONNECTED;
1393
1394                 INFO (dev, "connected\n");
1395                 event = next_event (dev, GADGETFS_CONNECT);
1396                 event->u.speed = gadget->speed;
1397                 ep0_readable (dev);
1398
1399         /* host may have given up waiting for response.  we can miss control
1400          * requests handled lower down (device/endpoint status and features);
1401          * then ep0_{read,write} will report the wrong status. controller
1402          * driver will have aborted pending i/o.
1403          */
1404         } else if (dev->state == STATE_DEV_SETUP)
1405                 dev->setup_abort = 1;
1406
1407         req->buf = dev->rbuf;
1408         req->context = NULL;
1409         value = -EOPNOTSUPP;
1410         switch (ctrl->bRequest) {
1411
1412         case USB_REQ_GET_DESCRIPTOR:
1413                 if (ctrl->bRequestType != USB_DIR_IN)
1414                         goto unrecognized;
1415                 switch (w_value >> 8) {
1416
1417                 case USB_DT_DEVICE:
1418                         value = min (w_length, (u16) sizeof *dev->dev);
1419                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1420                         req->buf = dev->dev;
1421                         break;
1422                 case USB_DT_DEVICE_QUALIFIER:
1423                         if (!dev->hs_config)
1424                                 break;
1425                         value = min (w_length, (u16)
1426                                 sizeof (struct usb_qualifier_descriptor));
1427                         make_qualifier (dev);
1428                         break;
1429                 case USB_DT_OTHER_SPEED_CONFIG:
1430                         // FALLTHROUGH
1431                 case USB_DT_CONFIG:
1432                         value = config_buf (dev,
1433                                         w_value >> 8,
1434                                         w_value & 0xff);
1435                         if (value >= 0)
1436                                 value = min (w_length, (u16) value);
1437                         break;
1438                 case USB_DT_STRING:
1439                         goto unrecognized;
1440
1441                 default:                // all others are errors
1442                         break;
1443                 }
1444                 break;
1445
1446         /* currently one config, two speeds */
1447         case USB_REQ_SET_CONFIGURATION:
1448                 if (ctrl->bRequestType != 0)
1449                         goto unrecognized;
1450                 if (0 == (u8) w_value) {
1451                         value = 0;
1452                         dev->current_config = 0;
1453                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1454                         // user mode expected to disable endpoints
1455                 } else {
1456                         u8      config, power;
1457
1458                         if (gadget_is_dualspeed(gadget)
1459                                         && gadget->speed == USB_SPEED_HIGH) {
1460                                 config = dev->hs_config->bConfigurationValue;
1461                                 power = dev->hs_config->bMaxPower;
1462                         } else {
1463                                 config = dev->config->bConfigurationValue;
1464                                 power = dev->config->bMaxPower;
1465                         }
1466
1467                         if (config == (u8) w_value) {
1468                                 value = 0;
1469                                 dev->current_config = config;
1470                                 usb_gadget_vbus_draw(gadget, 2 * power);
1471                         }
1472                 }
1473
1474                 /* report SET_CONFIGURATION like any other control request,
1475                  * except that usermode may not stall this.  the next
1476                  * request mustn't be allowed start until this finishes:
1477                  * endpoints and threads set up, etc.
1478                  *
1479                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1480                  * has bad/racey automagic that prevents synchronizing here.
1481                  * even kernel mode drivers often miss them.
1482                  */
1483                 if (value == 0) {
1484                         INFO (dev, "configuration #%d\n", dev->current_config);
1485                         if (dev->usermode_setup) {
1486                                 dev->setup_can_stall = 0;
1487                                 goto delegate;
1488                         }
1489                 }
1490                 break;
1491
1492 #ifndef CONFIG_USB_GADGET_PXA25X
1493         /* PXA automagically handles this request too */
1494         case USB_REQ_GET_CONFIGURATION:
1495                 if (ctrl->bRequestType != 0x80)
1496                         goto unrecognized;
1497                 *(u8 *)req->buf = dev->current_config;
1498                 value = min (w_length, (u16) 1);
1499                 break;
1500 #endif
1501
1502         default:
1503 unrecognized:
1504                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1505                         dev->usermode_setup ? "delegate" : "fail",
1506                         ctrl->bRequestType, ctrl->bRequest,
1507                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1508
1509                 /* if there's an ep0 reader, don't stall */
1510                 if (dev->usermode_setup) {
1511                         dev->setup_can_stall = 1;
1512 delegate:
1513                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1514                                                 ? 1 : 0;
1515                         dev->setup_wLength = w_length;
1516                         dev->setup_out_ready = 0;
1517                         dev->setup_out_error = 0;
1518                         value = 0;
1519
1520                         /* read DATA stage for OUT right away */
1521                         if (unlikely (!dev->setup_in && w_length)) {
1522                                 value = setup_req (gadget->ep0, dev->req,
1523                                                         w_length);
1524                                 if (value < 0)
1525                                         break;
1526                                 value = usb_ep_queue (gadget->ep0, dev->req,
1527                                                         GFP_ATOMIC);
1528                                 if (value < 0) {
1529                                         clean_req (gadget->ep0, dev->req);
1530                                         break;
1531                                 }
1532
1533                                 /* we can't currently stall these */
1534                                 dev->setup_can_stall = 0;
1535                         }
1536
1537                         /* state changes when reader collects event */
1538                         event = next_event (dev, GADGETFS_SETUP);
1539                         event->u.setup = *ctrl;
1540                         ep0_readable (dev);
1541                         spin_unlock (&dev->lock);
1542                         return 0;
1543                 }
1544         }
1545
1546         /* proceed with data transfer and status phases? */
1547         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1548                 req->length = value;
1549                 req->zero = value < w_length;
1550                 value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
1551                 if (value < 0) {
1552                         DBG (dev, "ep_queue --> %d\n", value);
1553                         req->status = 0;
1554                 }
1555         }
1556
1557         /* device stalls when value < 0 */
1558         spin_unlock (&dev->lock);
1559         return value;
1560 }
1561
1562 static void destroy_ep_files (struct dev_data *dev)
1563 {
1564         DBG (dev, "%s %d\n", __func__, dev->state);
1565
1566         /* dev->state must prevent interference */
1567         spin_lock_irq (&dev->lock);
1568         while (!list_empty(&dev->epfiles)) {
1569                 struct ep_data  *ep;
1570                 struct inode    *parent;
1571                 struct dentry   *dentry;
1572
1573                 /* break link to FS */
1574                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1575                 list_del_init (&ep->epfiles);
1576                 dentry = ep->dentry;
1577                 ep->dentry = NULL;
1578                 parent = dentry->d_parent->d_inode;
1579
1580                 /* break link to controller */
1581                 if (ep->state == STATE_EP_ENABLED)
1582                         (void) usb_ep_disable (ep->ep);
1583                 ep->state = STATE_EP_UNBOUND;
1584                 usb_ep_free_request (ep->ep, ep->req);
1585                 ep->ep = NULL;
1586                 wake_up (&ep->wait);
1587                 put_ep (ep);
1588
1589                 spin_unlock_irq (&dev->lock);
1590
1591                 /* break link to dcache */
1592                 mutex_lock (&parent->i_mutex);
1593                 d_delete (dentry);
1594                 dput (dentry);
1595                 mutex_unlock (&parent->i_mutex);
1596
1597                 spin_lock_irq (&dev->lock);
1598         }
1599         spin_unlock_irq (&dev->lock);
1600 }
1601
1602
1603 static struct inode *
1604 gadgetfs_create_file (struct super_block *sb, char const *name,
1605                 void *data, const struct file_operations *fops,
1606                 struct dentry **dentry_p);
1607
1608 static int activate_ep_files (struct dev_data *dev)
1609 {
1610         struct usb_ep   *ep;
1611         struct ep_data  *data;
1612
1613         gadget_for_each_ep (ep, dev->gadget) {
1614
1615                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1616                 if (!data)
1617                         goto enomem0;
1618                 data->state = STATE_EP_DISABLED;
1619                 mutex_init(&data->lock);
1620                 init_waitqueue_head (&data->wait);
1621
1622                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1623                 atomic_set (&data->count, 1);
1624                 data->dev = dev;
1625                 get_dev (dev);
1626
1627                 data->ep = ep;
1628                 ep->driver_data = data;
1629
1630                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1631                 if (!data->req)
1632                         goto enomem1;
1633
1634                 data->inode = gadgetfs_create_file (dev->sb, data->name,
1635                                 data, &ep_config_operations,
1636                                 &data->dentry);
1637                 if (!data->inode)
1638                         goto enomem2;
1639                 list_add_tail (&data->epfiles, &dev->epfiles);
1640         }
1641         return 0;
1642
1643 enomem2:
1644         usb_ep_free_request (ep, data->req);
1645 enomem1:
1646         put_dev (dev);
1647         kfree (data);
1648 enomem0:
1649         DBG (dev, "%s enomem\n", __func__);
1650         destroy_ep_files (dev);
1651         return -ENOMEM;
1652 }
1653
1654 static void
1655 gadgetfs_unbind (struct usb_gadget *gadget)
1656 {
1657         struct dev_data         *dev = get_gadget_data (gadget);
1658
1659         DBG (dev, "%s\n", __func__);
1660
1661         spin_lock_irq (&dev->lock);
1662         dev->state = STATE_DEV_UNBOUND;
1663         spin_unlock_irq (&dev->lock);
1664
1665         destroy_ep_files (dev);
1666         gadget->ep0->driver_data = NULL;
1667         set_gadget_data (gadget, NULL);
1668
1669         /* we've already been disconnected ... no i/o is active */
1670         if (dev->req)
1671                 usb_ep_free_request (gadget->ep0, dev->req);
1672         DBG (dev, "%s done\n", __func__);
1673         put_dev (dev);
1674 }
1675
1676 static struct dev_data          *the_device;
1677
1678 static int gadgetfs_bind(struct usb_gadget *gadget,
1679                 struct usb_gadget_driver *driver)
1680 {
1681         struct dev_data         *dev = the_device;
1682
1683         if (!dev)
1684                 return -ESRCH;
1685         if (0 != strcmp (CHIP, gadget->name)) {
1686                 pr_err("%s expected %s controller not %s\n",
1687                         shortname, CHIP, gadget->name);
1688                 return -ENODEV;
1689         }
1690
1691         set_gadget_data (gadget, dev);
1692         dev->gadget = gadget;
1693         gadget->ep0->driver_data = dev;
1694
1695         /* preallocate control response and buffer */
1696         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1697         if (!dev->req)
1698                 goto enomem;
1699         dev->req->context = NULL;
1700         dev->req->complete = epio_complete;
1701
1702         if (activate_ep_files (dev) < 0)
1703                 goto enomem;
1704
1705         INFO (dev, "bound to %s driver\n", gadget->name);
1706         spin_lock_irq(&dev->lock);
1707         dev->state = STATE_DEV_UNCONNECTED;
1708         spin_unlock_irq(&dev->lock);
1709         get_dev (dev);
1710         return 0;
1711
1712 enomem:
1713         gadgetfs_unbind (gadget);
1714         return -ENOMEM;
1715 }
1716
1717 static void
1718 gadgetfs_disconnect (struct usb_gadget *gadget)
1719 {
1720         struct dev_data         *dev = get_gadget_data (gadget);
1721         unsigned long           flags;
1722
1723         spin_lock_irqsave (&dev->lock, flags);
1724         if (dev->state == STATE_DEV_UNCONNECTED)
1725                 goto exit;
1726         dev->state = STATE_DEV_UNCONNECTED;
1727
1728         INFO (dev, "disconnected\n");
1729         next_event (dev, GADGETFS_DISCONNECT);
1730         ep0_readable (dev);
1731 exit:
1732         spin_unlock_irqrestore (&dev->lock, flags);
1733 }
1734
1735 static void
1736 gadgetfs_suspend (struct usb_gadget *gadget)
1737 {
1738         struct dev_data         *dev = get_gadget_data (gadget);
1739
1740         INFO (dev, "suspended from state %d\n", dev->state);
1741         spin_lock (&dev->lock);
1742         switch (dev->state) {
1743         case STATE_DEV_SETUP:           // VERY odd... host died??
1744         case STATE_DEV_CONNECTED:
1745         case STATE_DEV_UNCONNECTED:
1746                 next_event (dev, GADGETFS_SUSPEND);
1747                 ep0_readable (dev);
1748                 /* FALLTHROUGH */
1749         default:
1750                 break;
1751         }
1752         spin_unlock (&dev->lock);
1753 }
1754
1755 static struct usb_gadget_driver gadgetfs_driver = {
1756         .function       = (char *) driver_desc,
1757         .bind           = gadgetfs_bind,
1758         .unbind         = gadgetfs_unbind,
1759         .setup          = gadgetfs_setup,
1760         .disconnect     = gadgetfs_disconnect,
1761         .suspend        = gadgetfs_suspend,
1762
1763         .driver = {
1764                 .name           = (char *) shortname,
1765         },
1766 };
1767
1768 /*----------------------------------------------------------------------*/
1769
1770 static void gadgetfs_nop(struct usb_gadget *arg) { }
1771
1772 static int gadgetfs_probe(struct usb_gadget *gadget,
1773                 struct usb_gadget_driver *driver)
1774 {
1775         CHIP = gadget->name;
1776         return -EISNAM;
1777 }
1778
1779 static struct usb_gadget_driver probe_driver = {
1780         .max_speed      = USB_SPEED_HIGH,
1781         .bind           = gadgetfs_probe,
1782         .unbind         = gadgetfs_nop,
1783         .setup          = (void *)gadgetfs_nop,
1784         .disconnect     = gadgetfs_nop,
1785         .driver = {
1786                 .name           = "nop",
1787         },
1788 };
1789
1790
1791 /* DEVICE INITIALIZATION
1792  *
1793  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1794  *     status = write (fd, descriptors, sizeof descriptors)
1795  *
1796  * That write establishes the device configuration, so the kernel can
1797  * bind to the controller ... guaranteeing it can handle enumeration
1798  * at all necessary speeds.  Descriptor order is:
1799  *
1800  * . message tag (u32, host order) ... for now, must be zero; it
1801  *      would change to support features like multi-config devices
1802  * . full/low speed config ... all wTotalLength bytes (with interface,
1803  *      class, altsetting, endpoint, and other descriptors)
1804  * . high speed config ... all descriptors, for high speed operation;
1805  *      this one's optional except for high-speed hardware
1806  * . device descriptor
1807  *
1808  * Endpoints are not yet enabled. Drivers must wait until device
1809  * configuration and interface altsetting changes create
1810  * the need to configure (or unconfigure) them.
1811  *
1812  * After initialization, the device stays active for as long as that
1813  * $CHIP file is open.  Events must then be read from that descriptor,
1814  * such as configuration notifications.
1815  */
1816
1817 static int is_valid_config (struct usb_config_descriptor *config)
1818 {
1819         return config->bDescriptorType == USB_DT_CONFIG
1820                 && config->bLength == USB_DT_CONFIG_SIZE
1821                 && config->bConfigurationValue != 0
1822                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1823                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1824         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1825         /* FIXME check lengths: walk to end */
1826 }
1827
1828 static ssize_t
1829 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1830 {
1831         struct dev_data         *dev = fd->private_data;
1832         ssize_t                 value = len, length = len;
1833         unsigned                total;
1834         u32                     tag;
1835         char                    *kbuf;
1836
1837         if (len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4))
1838                 return -EINVAL;
1839
1840         /* we might need to change message format someday */
1841         if (copy_from_user (&tag, buf, 4))
1842                 return -EFAULT;
1843         if (tag != 0)
1844                 return -EINVAL;
1845         buf += 4;
1846         length -= 4;
1847
1848         kbuf = memdup_user(buf, length);
1849         if (IS_ERR(kbuf))
1850                 return PTR_ERR(kbuf);
1851
1852         spin_lock_irq (&dev->lock);
1853         value = -EINVAL;
1854         if (dev->buf)
1855                 goto fail;
1856         dev->buf = kbuf;
1857
1858         /* full or low speed config */
1859         dev->config = (void *) kbuf;
1860         total = le16_to_cpu(dev->config->wTotalLength);
1861         if (!is_valid_config (dev->config) || total >= length)
1862                 goto fail;
1863         kbuf += total;
1864         length -= total;
1865
1866         /* optional high speed config */
1867         if (kbuf [1] == USB_DT_CONFIG) {
1868                 dev->hs_config = (void *) kbuf;
1869                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1870                 if (!is_valid_config (dev->hs_config) || total >= length)
1871                         goto fail;
1872                 kbuf += total;
1873                 length -= total;
1874         }
1875
1876         /* could support multiple configs, using another encoding! */
1877
1878         /* device descriptor (tweaked for paranoia) */
1879         if (length != USB_DT_DEVICE_SIZE)
1880                 goto fail;
1881         dev->dev = (void *)kbuf;
1882         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1883                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1884                         || dev->dev->bNumConfigurations != 1)
1885                 goto fail;
1886         dev->dev->bNumConfigurations = 1;
1887         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1888
1889         /* triggers gadgetfs_bind(); then we can enumerate. */
1890         spin_unlock_irq (&dev->lock);
1891         if (dev->hs_config)
1892                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1893         else
1894                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1895
1896         value = usb_gadget_probe_driver(&gadgetfs_driver);
1897         if (value != 0) {
1898                 kfree (dev->buf);
1899                 dev->buf = NULL;
1900         } else {
1901                 /* at this point "good" hardware has for the first time
1902                  * let the USB the host see us.  alternatively, if users
1903                  * unplug/replug that will clear all the error state.
1904                  *
1905                  * note:  everything running before here was guaranteed
1906                  * to choke driver model style diagnostics.  from here
1907                  * on, they can work ... except in cleanup paths that
1908                  * kick in after the ep0 descriptor is closed.
1909                  */
1910                 fd->f_op = &ep0_io_operations;
1911                 value = len;
1912         }
1913         return value;
1914
1915 fail:
1916         spin_unlock_irq (&dev->lock);
1917         pr_debug ("%s: %s fail %Zd, %p\n", shortname, __func__, value, dev);
1918         kfree (dev->buf);
1919         dev->buf = NULL;
1920         return value;
1921 }
1922
1923 static int
1924 dev_open (struct inode *inode, struct file *fd)
1925 {
1926         struct dev_data         *dev = inode->i_private;
1927         int                     value = -EBUSY;
1928
1929         spin_lock_irq(&dev->lock);
1930         if (dev->state == STATE_DEV_DISABLED) {
1931                 dev->ev_next = 0;
1932                 dev->state = STATE_DEV_OPENED;
1933                 fd->private_data = dev;
1934                 get_dev (dev);
1935                 value = 0;
1936         }
1937         spin_unlock_irq(&dev->lock);
1938         return value;
1939 }
1940
1941 static const struct file_operations dev_init_operations = {
1942         .llseek =       no_llseek,
1943
1944         .open =         dev_open,
1945         .write =        dev_config,
1946         .fasync =       ep0_fasync,
1947         .unlocked_ioctl = dev_ioctl,
1948         .release =      dev_release,
1949 };
1950
1951 /*----------------------------------------------------------------------*/
1952
1953 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1954  *
1955  * Mounting the filesystem creates a controller file, used first for
1956  * device configuration then later for event monitoring.
1957  */
1958
1959
1960 /* FIXME PAM etc could set this security policy without mount options
1961  * if epfiles inherited ownership and permissons from ep0 ...
1962  */
1963
1964 static unsigned default_uid;
1965 static unsigned default_gid;
1966 static unsigned default_perm = S_IRUSR | S_IWUSR;
1967
1968 module_param (default_uid, uint, 0644);
1969 module_param (default_gid, uint, 0644);
1970 module_param (default_perm, uint, 0644);
1971
1972
1973 static struct inode *
1974 gadgetfs_make_inode (struct super_block *sb,
1975                 void *data, const struct file_operations *fops,
1976                 int mode)
1977 {
1978         struct inode *inode = new_inode (sb);
1979
1980         if (inode) {
1981                 inode->i_ino = get_next_ino();
1982                 inode->i_mode = mode;
1983                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
1984                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
1985                 inode->i_atime = inode->i_mtime = inode->i_ctime
1986                                 = CURRENT_TIME;
1987                 inode->i_private = data;
1988                 inode->i_fop = fops;
1989         }
1990         return inode;
1991 }
1992
1993 /* creates in fs root directory, so non-renamable and non-linkable.
1994  * so inode and dentry are paired, until device reconfig.
1995  */
1996 static struct inode *
1997 gadgetfs_create_file (struct super_block *sb, char const *name,
1998                 void *data, const struct file_operations *fops,
1999                 struct dentry **dentry_p)
2000 {
2001         struct dentry   *dentry;
2002         struct inode    *inode;
2003
2004         dentry = d_alloc_name(sb->s_root, name);
2005         if (!dentry)
2006                 return NULL;
2007
2008         inode = gadgetfs_make_inode (sb, data, fops,
2009                         S_IFREG | (default_perm & S_IRWXUGO));
2010         if (!inode) {
2011                 dput(dentry);
2012                 return NULL;
2013         }
2014         d_add (dentry, inode);
2015         *dentry_p = dentry;
2016         return inode;
2017 }
2018
2019 static const struct super_operations gadget_fs_operations = {
2020         .statfs =       simple_statfs,
2021         .drop_inode =   generic_delete_inode,
2022 };
2023
2024 static int
2025 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
2026 {
2027         struct inode    *inode;
2028         struct dev_data *dev;
2029
2030         if (the_device)
2031                 return -ESRCH;
2032
2033         /* fake probe to determine $CHIP */
2034         usb_gadget_probe_driver(&probe_driver);
2035         if (!CHIP)
2036                 return -ENODEV;
2037
2038         /* superblock */
2039         sb->s_blocksize = PAGE_CACHE_SIZE;
2040         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2041         sb->s_magic = GADGETFS_MAGIC;
2042         sb->s_op = &gadget_fs_operations;
2043         sb->s_time_gran = 1;
2044
2045         /* root inode */
2046         inode = gadgetfs_make_inode (sb,
2047                         NULL, &simple_dir_operations,
2048                         S_IFDIR | S_IRUGO | S_IXUGO);
2049         if (!inode)
2050                 goto Enomem;
2051         inode->i_op = &simple_dir_inode_operations;
2052         if (!(sb->s_root = d_make_root (inode)))
2053                 goto Enomem;
2054
2055         /* the ep0 file is named after the controller we expect;
2056          * user mode code can use it for sanity checks, like we do.
2057          */
2058         dev = dev_new ();
2059         if (!dev)
2060                 goto Enomem;
2061
2062         dev->sb = sb;
2063         if (!gadgetfs_create_file (sb, CHIP,
2064                                 dev, &dev_init_operations,
2065                                 &dev->dentry)) {
2066                 put_dev(dev);
2067                 goto Enomem;
2068         }
2069
2070         /* other endpoint files are available after hardware setup,
2071          * from binding to a controller.
2072          */
2073         the_device = dev;
2074         return 0;
2075
2076 Enomem:
2077         return -ENOMEM;
2078 }
2079
2080 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2081 static struct dentry *
2082 gadgetfs_mount (struct file_system_type *t, int flags,
2083                 const char *path, void *opts)
2084 {
2085         return mount_single (t, flags, opts, gadgetfs_fill_super);
2086 }
2087
2088 static void
2089 gadgetfs_kill_sb (struct super_block *sb)
2090 {
2091         kill_litter_super (sb);
2092         if (the_device) {
2093                 put_dev (the_device);
2094                 the_device = NULL;
2095         }
2096 }
2097
2098 /*----------------------------------------------------------------------*/
2099
2100 static struct file_system_type gadgetfs_type = {
2101         .owner          = THIS_MODULE,
2102         .name           = shortname,
2103         .mount          = gadgetfs_mount,
2104         .kill_sb        = gadgetfs_kill_sb,
2105 };
2106 MODULE_ALIAS_FS("gadgetfs");
2107
2108 /*----------------------------------------------------------------------*/
2109
2110 static int __init init (void)
2111 {
2112         int status;
2113
2114         status = register_filesystem (&gadgetfs_type);
2115         if (status == 0)
2116                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2117                         shortname, driver_desc);
2118         return status;
2119 }
2120 module_init (init);
2121
2122 static void __exit cleanup (void)
2123 {
2124         pr_debug ("unregister %s\n", shortname);
2125         unregister_filesystem (&gadgetfs_type);
2126 }
2127 module_exit (cleanup);
2128