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   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  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22
  23 /* #define VERBOSE_DEBUG */
  24
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/fs.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/uts.h>
  30 #include <linux/wait.h>
  31 #include <linux/compiler.h>
  32 #include <asm/uaccess.h>
  33 #include <linux/slab.h>
  34 #include <linux/poll.h>
  35 #include <linux/smp_lock.h>
  36
  37 #include <linux/device.h>
  38 #include <linux/moduleparam.h>
  39
  40 #include <linux/usb/gadgetfs.h>
  41 #include <linux/usb/gadget.h>
  42
  43
  44 /*
  45  * The gadgetfs API maps each endpoint to a file descriptor so that you
  46  * can use standard synchronous read/write calls for I/O.  There's some
  47  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  48  * drivers show how this works in practice.  You can also use AIO to
  49  * eliminate I/O gaps between requests, to help when streaming data.
  50  *
  51  * Key parts that must be USB-specific are protocols defining how the
  52  * read/write operations relate to the hardware state machines.  There
  53  * are two types of files.  One type is for the device, implementing ep0.
  54  * The other type is for each IN or OUT endpoint.  In both cases, the
  55  * user mode driver must configure the hardware before using it.
  56  *
  57  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  58  *   (by writing configuration and device descriptors).  Afterwards it
  59  *   may serve as a source of device events, used to handle all control
  60  *   requests other than basic enumeration.
  61  *
  62  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  63  *   called when each /dev/gadget/ep* file is configured (by writing
  64  *   endpoint descriptors).  Afterwards these files are used to write()
  65  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  66  *   direction" request is issued (like reading an IN endpoint).
  67  *
  68  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  69  * not possible on all hardware.  For example, precise fault handling with
  70  * respect to data left in endpoint fifos after aborted operations; or
  71  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  72  */
  73
  74 #define DRIVER_DESC     "USB Gadget filesystem"
  75 #define DRIVER_VERSION  "24 Aug 2004"
  76
  77 static const char driver_desc [] = DRIVER_DESC;
  78 static const char shortname [] = "gadgetfs";
  79
  80 MODULE_DESCRIPTION (DRIVER_DESC);
  81 MODULE_AUTHOR ("David Brownell");
  82 MODULE_LICENSE ("GPL");
  83
  84
  85 /*----------------------------------------------------------------------*/
  86
  87 #define GADGETFS_MAGIC          0xaee71ee7
  88 #define DMA_ADDR_INVALID        (~(dma_addr_t)0)
  89
  90 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  91 enum ep0_state {
  92         /* DISBLED is the initial state.
  93          */
  94         STATE_DEV_DISABLED = 0,
  95
  96         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  97          * ep0/device i/o modes and binding to the controller.  Driver
  98          * must always write descriptors to initialize the device, then
  99          * the device becomes UNCONNECTED until enumeration.
 100          */
 101         STATE_DEV_OPENED,
 102
 103         /* From then on, ep0 fd is in either of two basic modes:
 104          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
 105          * - SETUP: read/write will transfer control data and succeed;
 106          *   or if "wrong direction", performs protocol stall
 107          */
 108         STATE_DEV_UNCONNECTED,
 109         STATE_DEV_CONNECTED,
 110         STATE_DEV_SETUP,
 111
 112         /* UNBOUND means the driver closed ep0, so the device won't be
 113          * accessible again (DEV_DISABLED) until all fds are closed.
 114          */
 115         STATE_DEV_UNBOUND,
 116 };
 117
 118 /* enough for the whole queue: most events invalidate others */
 119 #define N_EVENT                 5
 120
 121 struct dev_data {
 122         spinlock_t                      lock;
 123         atomic_t                        count;
 124         enum ep0_state                  state;          /* P: lock */
 125         struct usb_gadgetfs_event       event [N_EVENT];
 126         unsigned                        ev_next;
 127         struct fasync_struct            *fasync;
 128         u8                              current_config;
 129
 130         /* drivers reading ep0 MUST handle control requests (SETUP)
 131          * reported that way; else the host will time out.
 132          */
 133         unsigned                        usermode_setup : 1,
 134                                         setup_in : 1,
 135                                         setup_can_stall : 1,
 136                                         setup_out_ready : 1,
 137                                         setup_out_error : 1,
 138                                         setup_abort : 1;
 139         unsigned                        setup_wLength;
 140
 141         /* the rest is basically write-once */
 142         struct usb_config_descriptor    *config, *hs_config;
 143         struct usb_device_descriptor    *dev;
 144         struct usb_request              *req;
 145         struct usb_gadget               *gadget;
 146         struct list_head                epfiles;
 147         void                            *buf;
 148         wait_queue_head_t               wait;
 149         struct super_block              *sb;
 150         struct dentry                   *dentry;
 151
 152         /* except this scratch i/o buffer for ep0 */
 153         u8                              rbuf [256];
 154 };
 155
 156 static inline void get_dev (struct dev_data *data)
 157 {
 158         atomic_inc (&data->count);
 159 }
 160
 161 static void put_dev (struct dev_data *data)
 162 {
 163         if (likely (!atomic_dec_and_test (&data->count)))
 164                 return;
 165         /* needs no more cleanup */
 166         BUG_ON (waitqueue_active (&data->wait));
 167         kfree (data);
 168 }
 169
 170 static struct dev_data *dev_new (void)
 171 {
 172         struct dev_data         *dev;
 173
 174         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 175         if (!dev)
 176                 return NULL;
 177         dev->state = STATE_DEV_DISABLED;
 178         atomic_set (&dev->count, 1);
 179         spin_lock_init (&dev->lock);
 180         INIT_LIST_HEAD (&dev->epfiles);
 181         init_waitqueue_head (&dev->wait);
 182         return dev;
 183 }
 184
 185 /*----------------------------------------------------------------------*/
 186
 187 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 188 enum ep_state {
 189         STATE_EP_DISABLED = 0,
 190         STATE_EP_READY,
 191         STATE_EP_ENABLED,
 192         STATE_EP_UNBOUND,
 193 };
 194
 195 struct ep_data {
 196         struct semaphore                lock;
 197         enum ep_state                   state;
 198         atomic_t                        count;
 199         struct dev_data                 *dev;
 200         /* must hold dev->lock before accessing ep or req */
 201         struct usb_ep                   *ep;
 202         struct usb_request              *req;
 203         ssize_t                         status;
 204         char                            name [16];
 205         struct usb_endpoint_descriptor  desc, hs_desc;
 206         struct list_head                epfiles;
 207         wait_queue_head_t               wait;
 208         struct dentry                   *dentry;
 209         struct inode                    *inode;
 210 };
 211
 212 static inline void get_ep (struct ep_data *data)
 213 {
 214         atomic_inc (&data->count);
 215 }
 216
 217 static void put_ep (struct ep_data *data)
 218 {
 219         if (likely (!atomic_dec_and_test (&data->count)))
 220                 return;
 221         put_dev (data->dev);
 222         /* needs no more cleanup */
 223         BUG_ON (!list_empty (&data->epfiles));
 224         BUG_ON (waitqueue_active (&data->wait));
 225         kfree (data);
 226 }
 227
 228 /*----------------------------------------------------------------------*/
 229
 230 /* most "how to use the hardware" policy choices are in userspace:
 231  * mapping endpoint roles (which the driver needs) to the capabilities
 232  * which the usb controller has.  most of those capabilities are exposed
 233  * implicitly, starting with the driver name and then endpoint names.
 234  */
 235
 236 static const char *CHIP;
 237
 238 /*----------------------------------------------------------------------*/
 239
 240 /* NOTE:  don't use dev_printk calls before binding to the gadget
 241  * at the end of ep0 configuration, or after unbind.
 242  */
 243
 244 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 245 #define xprintk(d,level,fmt,args...) \
 246         printk(level "%s: " fmt , shortname , ## args)
 247
 248 #ifdef DEBUG
 249 #define DBG(dev,fmt,args...) \
 250         xprintk(dev , KERN_DEBUG , fmt , ## args)
 251 #else
 252 #define DBG(dev,fmt,args...) \
 253         do { } while (0)
 254 #endif /* DEBUG */
 255
 256 #ifdef VERBOSE_DEBUG
 257 #define VDEBUG  DBG
 258 #else
 259 #define VDEBUG(dev,fmt,args...) \
 260         do { } while (0)
 261 #endif /* DEBUG */
 262
 263 #define ERROR(dev,fmt,args...) \
 264         xprintk(dev , KERN_ERR , fmt , ## args)
 265 #define WARN(dev,fmt,args...) \
 266         xprintk(dev , KERN_WARNING , fmt , ## args)
 267 #define INFO(dev,fmt,args...) \
 268         xprintk(dev , KERN_INFO , fmt , ## args)
 269
 270
 271 /*----------------------------------------------------------------------*/
 272
 273 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 274  *
 275  * After opening, configure non-control endpoints.  Then use normal
 276  * stream read() and write() requests; and maybe ioctl() to get more
 277  * precise FIFO status when recovering from cancellation.
 278  */
 279
 280 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 281 {
 282         struct ep_data  *epdata = ep->driver_data;
 283
 284         if (!req->context)
 285                 return;
 286         if (req->status)
 287                 epdata->status = req->status;
 288         else
 289                 epdata->status = req->actual;
 290         complete ((struct completion *)req->context);
 291 }
 292
 293 /* tasklock endpoint, returning when it's connected.
 294  * still need dev->lock to use epdata->ep.
 295  */
 296 static int
 297 get_ready_ep (unsigned f_flags, struct ep_data *epdata)
 298 {
 299         int     val;
 300
 301         if (f_flags & O_NONBLOCK) {
 302                 if (down_trylock (&epdata->lock) != 0)
 303                         goto nonblock;
 304                 if (epdata->state != STATE_EP_ENABLED) {
 305                         up (&epdata->lock);
 306 nonblock:
 307                         val = -EAGAIN;
 308                 } else
 309                         val = 0;
 310                 return val;
 311         }
 312
 313         if ((val = down_interruptible (&epdata->lock)) < 0)
 314                 return val;
 315
 316         switch (epdata->state) {
 317         case STATE_EP_ENABLED:
 318                 break;
 319         // case STATE_EP_DISABLED:              /* "can't happen" */
 320         // case STATE_EP_READY:                 /* "can't happen" */
 321         default:                                /* error! */
 322                 pr_debug ("%s: ep %p not available, state %d\n",
 323                                 shortname, epdata, epdata->state);
 324                 // FALLTHROUGH
 325         case STATE_EP_UNBOUND:                  /* clean disconnect */
 326                 val = -ENODEV;
 327                 up (&epdata->lock);
 328         }
 329         return val;
 330 }
 331
 332 static ssize_t
 333 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 334 {
 335         DECLARE_COMPLETION_ONSTACK (done);
 336         int value;
 337
 338         spin_lock_irq (&epdata->dev->lock);
 339         if (likely (epdata->ep != NULL)) {
 340                 struct usb_request      *req = epdata->req;
 341
 342                 req->context = &done;
 343                 req->complete = epio_complete;
 344                 req->buf = buf;
 345                 req->length = len;
 346                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 347         } else
 348                 value = -ENODEV;
 349         spin_unlock_irq (&epdata->dev->lock);
 350
 351         if (likely (value == 0)) {
 352                 value = wait_event_interruptible (done.wait, done.done);
 353                 if (value != 0) {
 354                         spin_lock_irq (&epdata->dev->lock);
 355                         if (likely (epdata->ep != NULL)) {
 356                                 DBG (epdata->dev, "%s i/o interrupted\n",
 357                                                 epdata->name);
 358                                 usb_ep_dequeue (epdata->ep, epdata->req);
 359                                 spin_unlock_irq (&epdata->dev->lock);
 360
 361                                 wait_event (done.wait, done.done);
 362                                 if (epdata->status == -ECONNRESET)
 363                                         epdata->status = -EINTR;
 364                         } else {
 365                                 spin_unlock_irq (&epdata->dev->lock);
 366
 367                                 DBG (epdata->dev, "endpoint gone\n");
 368                                 epdata->status = -ENODEV;
 369                         }
 370                 }
 371                 return epdata->status;
 372         }
 373         return value;
 374 }
 375
 376
 377 /* handle a synchronous OUT bulk/intr/iso transfer */
 378 static ssize_t
 379 ep_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 380 {
 381         struct ep_data          *data = fd->private_data;
 382         void                    *kbuf;
 383         ssize_t                 value;
 384
 385         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
 386                 return value;
 387
 388         /* halt any endpoint by doing a "wrong direction" i/o call */
 389         if (data->desc.bEndpointAddress & USB_DIR_IN) {
 390                 if ((data->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
 391                                 == USB_ENDPOINT_XFER_ISOC)
 392                         return -EINVAL;
 393                 DBG (data->dev, "%s halt\n", data->name);
 394                 spin_lock_irq (&data->dev->lock);
 395                 if (likely (data->ep != NULL))
 396                         usb_ep_set_halt (data->ep);
 397                 spin_unlock_irq (&data->dev->lock);
 398                 up (&data->lock);
 399                 return -EBADMSG;
 400         }
 401
 402         /* FIXME readahead for O_NONBLOCK and poll(); careful with ZLPs */
 403
 404         value = -ENOMEM;
 405         kbuf = kmalloc (len, GFP_KERNEL);
 406         if (unlikely (!kbuf))
 407                 goto free1;
 408
 409         value = ep_io (data, kbuf, len);
 410         VDEBUG (data->dev, "%s read %zu OUT, status %d\n",
 411                 data->name, len, (int) value);
 412         if (value >= 0 && copy_to_user (buf, kbuf, value))
 413                 value = -EFAULT;
 414
 415 free1:
 416         up (&data->lock);
 417         kfree (kbuf);
 418         return value;
 419 }
 420
 421 /* handle a synchronous IN bulk/intr/iso transfer */
 422 static ssize_t
 423 ep_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 424 {
 425         struct ep_data          *data = fd->private_data;
 426         void                    *kbuf;
 427         ssize_t                 value;
 428
 429         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
 430                 return value;
 431
 432         /* halt any endpoint by doing a "wrong direction" i/o call */
 433         if (!(data->desc.bEndpointAddress & USB_DIR_IN)) {
 434                 if ((data->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
 435                                 == USB_ENDPOINT_XFER_ISOC)
 436                         return -EINVAL;
 437                 DBG (data->dev, "%s halt\n", data->name);
 438                 spin_lock_irq (&data->dev->lock);
 439                 if (likely (data->ep != NULL))
 440                         usb_ep_set_halt (data->ep);
 441                 spin_unlock_irq (&data->dev->lock);
 442                 up (&data->lock);
 443                 return -EBADMSG;
 444         }
 445
 446         /* FIXME writebehind for O_NONBLOCK and poll(), qlen = 1 */
 447
 448         value = -ENOMEM;
 449         kbuf = kmalloc (len, GFP_KERNEL);
 450         if (!kbuf)
 451                 goto free1;
 452         if (copy_from_user (kbuf, buf, len)) {
 453                 value = -EFAULT;
 454                 goto free1;
 455         }
 456
 457         value = ep_io (data, kbuf, len);
 458         VDEBUG (data->dev, "%s write %zu IN, status %d\n",
 459                 data->name, len, (int) value);
 460 free1:
 461         up (&data->lock);
 462         kfree (kbuf);
 463         return value;
 464 }
 465
 466 static int
 467 ep_release (struct inode *inode, struct file *fd)
 468 {
 469         struct ep_data          *data = fd->private_data;
 470         int value;
 471
 472         if ((value = down_interruptible(&data->lock)) < 0)
 473                 return value;
 474
 475         /* clean up if this can be reopened */
 476         if (data->state != STATE_EP_UNBOUND) {
 477                 data->state = STATE_EP_DISABLED;
 478                 data->desc.bDescriptorType = 0;
 479                 data->hs_desc.bDescriptorType = 0;
 480                 usb_ep_disable(data->ep);
 481         }
 482         up (&data->lock);
 483         put_ep (data);
 484         return 0;
 485 }
 486
 487 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 488 {
 489         struct ep_data          *data = fd->private_data;
 490         int                     status;
 491
 492         if ((status = get_ready_ep (fd->f_flags, data)) < 0)
 493                 return status;
 494
 495         spin_lock_irq (&data->dev->lock);
 496         if (likely (data->ep != NULL)) {
 497                 switch (code) {
 498                 case GADGETFS_FIFO_STATUS:
 499                         status = usb_ep_fifo_status (data->ep);
 500                         break;
 501                 case GADGETFS_FIFO_FLUSH:
 502                         usb_ep_fifo_flush (data->ep);
 503                         break;
 504                 case GADGETFS_CLEAR_HALT:
 505                         status = usb_ep_clear_halt (data->ep);
 506                         break;
 507                 default:
 508                         status = -ENOTTY;
 509                 }
 510         } else
 511                 status = -ENODEV;
 512         spin_unlock_irq (&data->dev->lock);
 513         up (&data->lock);
 514         return status;
 515 }
 516
 517 /*----------------------------------------------------------------------*/
 518
 519 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 520
 521 struct kiocb_priv {
 522         struct usb_request      *req;
 523         struct ep_data          *epdata;
 524         void                    *buf;
 525         const struct iovec      *iv;
 526         unsigned long           nr_segs;
 527         unsigned                actual;
 528 };
 529
 530 static int ep_aio_cancel(struct kiocb *iocb, struct io_event *e)
 531 {
 532         struct kiocb_priv       *priv = iocb->private;
 533         struct ep_data          *epdata;
 534         int                     value;
 535
 536         local_irq_disable();
 537         epdata = priv->epdata;
 538         // spin_lock(&epdata->dev->lock);
 539         kiocbSetCancelled(iocb);
 540         if (likely(epdata && epdata->ep && priv->req))
 541                 value = usb_ep_dequeue (epdata->ep, priv->req);
 542         else
 543                 value = -EINVAL;
 544         // spin_unlock(&epdata->dev->lock);
 545         local_irq_enable();
 546
 547         aio_put_req(iocb);
 548         return value;
 549 }
 550
 551 static ssize_t ep_aio_read_retry(struct kiocb *iocb)
 552 {
 553         struct kiocb_priv       *priv = iocb->private;
 554         ssize_t                 len, total;
 555         void                    *to_copy;
 556         int                     i;
 557
 558         /* we "retry" to get the right mm context for this: */
 559
 560         /* copy stuff into user buffers */
 561         total = priv->actual;
 562         len = 0;
 563         to_copy = priv->buf;
 564         for (i=0; i < priv->nr_segs; i++) {
 565                 ssize_t this = min((ssize_t)(priv->iv[i].iov_len), total);
 566
 567                 if (copy_to_user(priv->iv[i].iov_base, to_copy, this)) {
 568                         if (len == 0)
 569                                 len = -EFAULT;
 570                         break;
 571                 }
 572
 573                 total -= this;
 574                 len += this;
 575                 to_copy += this;
 576                 if (total == 0)
 577                         break;
 578         }
 579         kfree(priv->buf);
 580         kfree(priv);
 581         return len;
 582 }
 583
 584 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 585 {
 586         struct kiocb            *iocb = req->context;
 587         struct kiocb_priv       *priv = iocb->private;
 588         struct ep_data          *epdata = priv->epdata;
 589
 590         /* lock against disconnect (and ideally, cancel) */
 591         spin_lock(&epdata->dev->lock);
 592         priv->req = NULL;
 593         priv->epdata = NULL;
 594
 595         /* if this was a write or a read returning no data then we
 596          * don't need to copy anything to userspace, so we can
 597          * complete the aio request immediately.
 598          */
 599         if (priv->iv == NULL || unlikely(req->actual == 0)) {
 600                 kfree(req->buf);
 601                 kfree(priv);
 602                 iocb->private = NULL;
 603                 /* aio_complete() reports bytes-transferred _and_ faults */
 604                 aio_complete(iocb, req->actual ? req->actual : req->status,
 605                                 req->status);
 606         } else {
 607                 /* retry() won't report both; so we hide some faults */
 608                 if (unlikely(0 != req->status))
 609                         DBG(epdata->dev, "%s fault %d len %d\n",
 610                                 ep->name, req->status, req->actual);
 611
 612                 priv->buf = req->buf;
 613                 priv->actual = req->actual;
 614                 kick_iocb(iocb);
 615         }
 616         spin_unlock(&epdata->dev->lock);
 617
 618         usb_ep_free_request(ep, req);
 619         put_ep(epdata);
 620 }
 621
 622 static ssize_t
 623 ep_aio_rwtail(
 624         struct kiocb    *iocb,
 625         char            *buf,
 626         size_t          len,
 627         struct ep_data  *epdata,
 628         const struct iovec *iv,
 629         unsigned long   nr_segs
 630 )
 631 {
 632         struct kiocb_priv       *priv;
 633         struct usb_request      *req;
 634         ssize_t                 value;
 635
 636         priv = kmalloc(sizeof *priv, GFP_KERNEL);
 637         if (!priv) {
 638                 value = -ENOMEM;
 639 fail:
 640                 kfree(buf);
 641                 return value;
 642         }
 643         iocb->private = priv;
 644         priv->iv = iv;
 645         priv->nr_segs = nr_segs;
 646
 647         value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
 648         if (unlikely(value < 0)) {
 649                 kfree(priv);
 650                 goto fail;
 651         }
 652
 653         iocb->ki_cancel = ep_aio_cancel;
 654         get_ep(epdata);
 655         priv->epdata = epdata;
 656         priv->actual = 0;
 657
 658         /* each kiocb is coupled to one usb_request, but we can't
 659          * allocate or submit those if the host disconnected.
 660          */
 661         spin_lock_irq(&epdata->dev->lock);
 662         if (likely(epdata->ep)) {
 663                 req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 664                 if (likely(req)) {
 665                         priv->req = req;
 666                         req->buf = buf;
 667                         req->length = len;
 668                         req->complete = ep_aio_complete;
 669                         req->context = iocb;
 670                         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 671                         if (unlikely(0 != value))
 672                                 usb_ep_free_request(epdata->ep, req);
 673                 } else
 674                         value = -EAGAIN;
 675         } else
 676                 value = -ENODEV;
 677         spin_unlock_irq(&epdata->dev->lock);
 678
 679         up(&epdata->lock);
 680
 681         if (unlikely(value)) {
 682                 kfree(priv);
 683                 put_ep(epdata);
 684         } else
 685                 value = (iv ? -EIOCBRETRY : -EIOCBQUEUED);
 686         return value;
 687 }
 688
 689 static ssize_t
 690 ep_aio_read(struct kiocb *iocb, const struct iovec *iov,
 691                 unsigned long nr_segs, loff_t o)
 692 {
 693         struct ep_data          *epdata = iocb->ki_filp->private_data;
 694         char                    *buf;
 695
 696         if (unlikely(epdata->desc.bEndpointAddress & USB_DIR_IN))
 697                 return -EINVAL;
 698
 699         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 700         if (unlikely(!buf))
 701                 return -ENOMEM;
 702
 703         iocb->ki_retry = ep_aio_read_retry;
 704         return ep_aio_rwtail(iocb, buf, iocb->ki_left, epdata, iov, nr_segs);
 705 }
 706
 707 static ssize_t
 708 ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
 709                 unsigned long nr_segs, loff_t o)
 710 {
 711         struct ep_data          *epdata = iocb->ki_filp->private_data;
 712         char                    *buf;
 713         size_t                  len = 0;
 714         int                     i = 0;
 715
 716         if (unlikely(!(epdata->desc.bEndpointAddress & USB_DIR_IN)))
 717                 return -EINVAL;
 718
 719         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 720         if (unlikely(!buf))
 721                 return -ENOMEM;
 722
 723         for (i=0; i < nr_segs; i++) {
 724                 if (unlikely(copy_from_user(&buf[len], iov[i].iov_base,
 725                                 iov[i].iov_len) != 0)) {
 726                         kfree(buf);
 727                         return -EFAULT;
 728                 }
 729                 len += iov[i].iov_len;
 730         }
 731         return ep_aio_rwtail(iocb, buf, len, epdata, NULL, 0);
 732 }
 733
 734 /*----------------------------------------------------------------------*/
 735
 736 /* used after endpoint configuration */
 737 static const struct file_operations ep_io_operations = {
 738         .owner =        THIS_MODULE,
 739         .llseek =       no_llseek,
 740
 741         .read =         ep_read,
 742         .write =        ep_write,
 743         .unlocked_ioctl = ep_ioctl,
 744         .release =      ep_release,
 745
 746         .aio_read =     ep_aio_read,
 747         .aio_write =    ep_aio_write,
 748 };
 749
 750 /* ENDPOINT INITIALIZATION
 751  *
 752  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 753  *     status = write (fd, descriptors, sizeof descriptors)
 754  *
 755  * That write establishes the endpoint configuration, configuring
 756  * the controller to process bulk, interrupt, or isochronous transfers
 757  * at the right maxpacket size, and so on.
 758  *
 759  * The descriptors are message type 1, identified by a host order u32
 760  * at the beginning of what's written.  Descriptor order is: full/low
 761  * speed descriptor, then optional high speed descriptor.
 762  */
 763 static ssize_t
 764 ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 765 {
 766         struct ep_data          *data = fd->private_data;
 767         struct usb_ep           *ep;
 768         u32                     tag;
 769         int                     value, length = len;
 770
 771         if ((value = down_interruptible (&data->lock)) < 0)
 772                 return value;
 773
 774         if (data->state != STATE_EP_READY) {
 775                 value = -EL2HLT;
 776                 goto fail;
 777         }
 778
 779         value = len;
 780         if (len < USB_DT_ENDPOINT_SIZE + 4)
 781                 goto fail0;
 782
 783         /* we might need to change message format someday */
 784         if (copy_from_user (&tag, buf, 4)) {
 785                 goto fail1;
 786         }
 787         if (tag != 1) {
 788                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 789                 goto fail0;
 790         }
 791         buf += 4;
 792         len -= 4;
 793
 794         /* NOTE:  audio endpoint extensions not accepted here;
 795          * just don't include the extra bytes.
 796          */
 797
 798         /* full/low speed descriptor, then high speed */
 799         if (copy_from_user (&data->desc, buf, USB_DT_ENDPOINT_SIZE)) {
 800                 goto fail1;
 801         }
 802         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 803                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 804                 goto fail0;
 805         if (len != USB_DT_ENDPOINT_SIZE) {
 806                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 807                         goto fail0;
 808                 if (copy_from_user (&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 809                                         USB_DT_ENDPOINT_SIZE)) {
 810                         goto fail1;
 811                 }
 812                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 813                                 || data->hs_desc.bDescriptorType
 814                                         != USB_DT_ENDPOINT) {
 815                         DBG(data->dev, "config %s, bad hs length or type\n",
 816                                         data->name);
 817                         goto fail0;
 818                 }
 819         }
 820
 821         spin_lock_irq (&data->dev->lock);
 822         if (data->dev->state == STATE_DEV_UNBOUND) {
 823                 value = -ENOENT;
 824                 goto gone;
 825         } else if ((ep = data->ep) == NULL) {
 826                 value = -ENODEV;
 827                 goto gone;
 828         }
 829         switch (data->dev->gadget->speed) {
 830         case USB_SPEED_LOW:
 831         case USB_SPEED_FULL:
 832                 value = usb_ep_enable (ep, &data->desc);
 833                 if (value == 0)
 834                         data->state = STATE_EP_ENABLED;
 835                 break;
 836 #ifdef  CONFIG_USB_GADGET_DUALSPEED
 837         case USB_SPEED_HIGH:
 838                 /* fails if caller didn't provide that descriptor... */
 839                 value = usb_ep_enable (ep, &data->hs_desc);
 840                 if (value == 0)
 841                         data->state = STATE_EP_ENABLED;
 842                 break;
 843 #endif
 844         default:
 845                 DBG(data->dev, "unconnected, %s init abandoned\n",
 846                                 data->name);
 847                 value = -EINVAL;
 848         }
 849         if (value == 0) {
 850                 fd->f_op = &ep_io_operations;
 851                 value = length;
 852         }
 853 gone:
 854         spin_unlock_irq (&data->dev->lock);
 855         if (value < 0) {
 856 fail:
 857                 data->desc.bDescriptorType = 0;
 858                 data->hs_desc.bDescriptorType = 0;
 859         }
 860         up (&data->lock);
 861         return value;
 862 fail0:
 863         value = -EINVAL;
 864         goto fail;
 865 fail1:
 866         value = -EFAULT;
 867         goto fail;
 868 }
 869
 870 static int
 871 ep_open (struct inode *inode, struct file *fd)
 872 {
 873         struct ep_data          *data = inode->i_private;
 874         int                     value = -EBUSY;
 875
 876         if (down_interruptible (&data->lock) != 0)
 877                 return -EINTR;
 878         spin_lock_irq (&data->dev->lock);
 879         if (data->dev->state == STATE_DEV_UNBOUND)
 880                 value = -ENOENT;
 881         else if (data->state == STATE_EP_DISABLED) {
 882                 value = 0;
 883                 data->state = STATE_EP_READY;
 884                 get_ep (data);
 885                 fd->private_data = data;
 886                 VDEBUG (data->dev, "%s ready\n", data->name);
 887         } else
 888                 DBG (data->dev, "%s state %d\n",
 889                         data->name, data->state);
 890         spin_unlock_irq (&data->dev->lock);
 891         up (&data->lock);
 892         return value;
 893 }
 894
 895 /* used before endpoint configuration */
 896 static const struct file_operations ep_config_operations = {
 897         .owner =        THIS_MODULE,
 898         .llseek =       no_llseek,
 899
 900         .open =         ep_open,
 901         .write =        ep_config,
 902         .release =      ep_release,
 903 };
 904
 905 /*----------------------------------------------------------------------*/
 906
 907 /* EP0 IMPLEMENTATION can be partly in userspace.
 908  *
 909  * Drivers that use this facility receive various events, including
 910  * control requests the kernel doesn't handle.  Drivers that don't
 911  * use this facility may be too simple-minded for real applications.
 912  */
 913
 914 static inline void ep0_readable (struct dev_data *dev)
 915 {
 916         wake_up (&dev->wait);
 917         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 918 }
 919
 920 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 921 {
 922         struct dev_data         *dev = ep->driver_data;
 923
 924         if (req->buf != dev->rbuf) {
 925                 kfree(req->buf);
 926                 req->buf = dev->rbuf;
 927                 req->dma = DMA_ADDR_INVALID;
 928         }
 929         req->complete = epio_complete;
 930         dev->setup_out_ready = 0;
 931 }
 932
 933 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 934 {
 935         struct dev_data         *dev = ep->driver_data;
 936         unsigned long           flags;
 937         int                     free = 1;
 938
 939         /* for control OUT, data must still get to userspace */
 940         spin_lock_irqsave(&dev->lock, flags);
 941         if (!dev->setup_in) {
 942                 dev->setup_out_error = (req->status != 0);
 943                 if (!dev->setup_out_error)
 944                         free = 0;
 945                 dev->setup_out_ready = 1;
 946                 ep0_readable (dev);
 947         }
 948
 949         /* clean up as appropriate */
 950         if (free && req->buf != &dev->rbuf)
 951                 clean_req (ep, req);
 952         req->complete = epio_complete;
 953         spin_unlock_irqrestore(&dev->lock, flags);
 954 }
 955
 956 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 957 {
 958         struct dev_data *dev = ep->driver_data;
 959
 960         if (dev->setup_out_ready) {
 961                 DBG (dev, "ep0 request busy!\n");
 962                 return -EBUSY;
 963         }
 964         if (len > sizeof (dev->rbuf))
 965                 req->buf = kmalloc(len, GFP_ATOMIC);
 966         if (req->buf == NULL) {
 967                 req->buf = dev->rbuf;
 968                 return -ENOMEM;
 969         }
 970         req->complete = ep0_complete;
 971         req->length = len;
 972         req->zero = 0;
 973         return 0;
 974 }
 975
 976 static ssize_t
 977 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 978 {
 979         struct dev_data                 *dev = fd->private_data;
 980         ssize_t                         retval;
 981         enum ep0_state                  state;
 982
 983         spin_lock_irq (&dev->lock);
 984
 985         /* report fd mode change before acting on it */
 986         if (dev->setup_abort) {
 987                 dev->setup_abort = 0;
 988                 retval = -EIDRM;
 989                 goto done;
 990         }
 991
 992         /* control DATA stage */
 993         if ((state = dev->state) == STATE_DEV_SETUP) {
 994
 995                 if (dev->setup_in) {            /* stall IN */
 996                         VDEBUG(dev, "ep0in stall\n");
 997                         (void) usb_ep_set_halt (dev->gadget->ep0);
 998                         retval = -EL2HLT;
 999                         dev->state = STATE_DEV_CONNECTED;
1000
1001                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
1002                         struct usb_ep           *ep = dev->gadget->ep0;
1003                         struct usb_request      *req = dev->req;
1004
1005                         if ((retval = setup_req (ep, req, 0)) == 0)
1006                                 retval = usb_ep_queue (ep, req, GFP_ATOMIC);
1007                         dev->state = STATE_DEV_CONNECTED;
1008
1009                         /* assume that was SET_CONFIGURATION */
1010                         if (dev->current_config) {
1011                                 unsigned power;
1012
1013                                 if (gadget_is_dualspeed(dev->gadget)
1014                                                 && (dev->gadget->speed
1015                                                         == USB_SPEED_HIGH))
1016                                         power = dev->hs_config->bMaxPower;
1017                                 else
1018                                         power = dev->config->bMaxPower;
1019                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
1020                         }
1021
1022                 } else {                        /* collect OUT data */
1023                         if ((fd->f_flags & O_NONBLOCK) != 0
1024                                         && !dev->setup_out_ready) {
1025                                 retval = -EAGAIN;
1026                                 goto done;
1027                         }
1028                         spin_unlock_irq (&dev->lock);
1029                         retval = wait_event_interruptible (dev->wait,
1030                                         dev->setup_out_ready != 0);
1031
1032                         /* FIXME state could change from under us */
1033                         spin_lock_irq (&dev->lock);
1034                         if (retval)
1035                                 goto done;
1036
1037                         if (dev->state != STATE_DEV_SETUP) {
1038                                 retval = -ECANCELED;
1039                                 goto done;
1040                         }
1041                         dev->state = STATE_DEV_CONNECTED;
1042
1043                         if (dev->setup_out_error)
1044                                 retval = -EIO;
1045                         else {
1046                                 len = min (len, (size_t)dev->req->actual);
1047 // FIXME don't call this with the spinlock held ...
1048                                 if (copy_to_user (buf, dev->req->buf, len))
1049                                         retval = -EFAULT;
1050                                 clean_req (dev->gadget->ep0, dev->req);
1051                                 /* NOTE userspace can't yet choose to stall */
1052                         }
1053                 }
1054                 goto done;
1055         }
1056
1057         /* else normal: return event data */
1058         if (len < sizeof dev->event [0]) {
1059                 retval = -EINVAL;
1060                 goto done;
1061         }
1062         len -= len % sizeof (struct usb_gadgetfs_event);
1063         dev->usermode_setup = 1;
1064
1065 scan:
1066         /* return queued events right away */
1067         if (dev->ev_next != 0) {
1068                 unsigned                i, n;
1069
1070                 n = len / sizeof (struct usb_gadgetfs_event);
1071                 if (dev->ev_next < n)
1072                         n = dev->ev_next;
1073
1074                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1075                 for (i = 0; i < n; i++) {
1076                         if (dev->event [i].type == GADGETFS_SETUP) {
1077                                 dev->state = STATE_DEV_SETUP;
1078                                 n = i + 1;
1079                                 break;
1080                         }
1081                 }
1082                 spin_unlock_irq (&dev->lock);
1083                 len = n * sizeof (struct usb_gadgetfs_event);
1084                 if (copy_to_user (buf, &dev->event, len))
1085                         retval = -EFAULT;
1086                 else
1087                         retval = len;
1088                 if (len > 0) {
1089                         /* NOTE this doesn't guard against broken drivers;
1090                          * concurrent ep0 readers may lose events.
1091                          */
1092                         spin_lock_irq (&dev->lock);
1093                         if (dev->ev_next > n) {
1094                                 memmove(&dev->event[0], &dev->event[n],
1095                                         sizeof (struct usb_gadgetfs_event)
1096                                                 * (dev->ev_next - n));
1097                         }
1098                         dev->ev_next -= n;
1099                         spin_unlock_irq (&dev->lock);
1100                 }
1101                 return retval;
1102         }
1103         if (fd->f_flags & O_NONBLOCK) {
1104                 retval = -EAGAIN;
1105                 goto done;
1106         }
1107
1108         switch (state) {
1109         default:
1110                 DBG (dev, "fail %s, state %d\n", __func__, state);
1111                 retval = -ESRCH;
1112                 break;
1113         case STATE_DEV_UNCONNECTED:
1114         case STATE_DEV_CONNECTED:
1115                 spin_unlock_irq (&dev->lock);
1116                 DBG (dev, "%s wait\n", __func__);
1117
1118                 /* wait for events */
1119                 retval = wait_event_interruptible (dev->wait,
1120                                 dev->ev_next != 0);
1121                 if (retval < 0)
1122                         return retval;
1123                 spin_lock_irq (&dev->lock);
1124                 goto scan;
1125         }
1126
1127 done:
1128         spin_unlock_irq (&dev->lock);
1129         return retval;
1130 }
1131
1132 static struct usb_gadgetfs_event *
1133 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1134 {
1135         struct usb_gadgetfs_event       *event;
1136         unsigned                        i;
1137
1138         switch (type) {
1139         /* these events purge the queue */
1140         case GADGETFS_DISCONNECT:
1141                 if (dev->state == STATE_DEV_SETUP)
1142                         dev->setup_abort = 1;
1143                 // FALL THROUGH
1144         case GADGETFS_CONNECT:
1145                 dev->ev_next = 0;
1146                 break;
1147         case GADGETFS_SETUP:            /* previous request timed out */
1148         case GADGETFS_SUSPEND:          /* same effect */
1149                 /* these events can't be repeated */
1150                 for (i = 0; i != dev->ev_next; i++) {
1151                         if (dev->event [i].type != type)
1152                                 continue;
1153                         DBG(dev, "discard old event[%d] %d\n", i, type);
1154                         dev->ev_next--;
1155                         if (i == dev->ev_next)
1156                                 break;
1157                         /* indices start at zero, for simplicity */
1158                         memmove (&dev->event [i], &dev->event [i + 1],
1159                                 sizeof (struct usb_gadgetfs_event)
1160                                         * (dev->ev_next - i));
1161                 }
1162                 break;
1163         default:
1164                 BUG ();
1165         }
1166         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1167         event = &dev->event [dev->ev_next++];
1168         BUG_ON (dev->ev_next > N_EVENT);
1169         memset (event, 0, sizeof *event);
1170         event->type = type;
1171         return event;
1172 }
1173
1174 static ssize_t
1175 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1176 {
1177         struct dev_data         *dev = fd->private_data;
1178         ssize_t                 retval = -ESRCH;
1179
1180         spin_lock_irq (&dev->lock);
1181
1182         /* report fd mode change before acting on it */
1183         if (dev->setup_abort) {
1184                 dev->setup_abort = 0;
1185                 retval = -EIDRM;
1186
1187         /* data and/or status stage for control request */
1188         } else if (dev->state == STATE_DEV_SETUP) {
1189
1190                 /* IN DATA+STATUS caller makes len <= wLength */
1191                 if (dev->setup_in) {
1192                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1193                         if (retval == 0) {
1194                                 dev->state = STATE_DEV_CONNECTED;
1195                                 spin_unlock_irq (&dev->lock);
1196                                 if (copy_from_user (dev->req->buf, buf, len))
1197                                         retval = -EFAULT;
1198                                 else {
1199                                         if (len < dev->setup_wLength)
1200                                                 dev->req->zero = 1;
1201                                         retval = usb_ep_queue (
1202                                                 dev->gadget->ep0, dev->req,
1203                                                 GFP_KERNEL);
1204                                 }
1205                                 if (retval < 0) {
1206                                         spin_lock_irq (&dev->lock);
1207                                         clean_req (dev->gadget->ep0, dev->req);
1208                                         spin_unlock_irq (&dev->lock);
1209                                 } else
1210                                         retval = len;
1211
1212                                 return retval;
1213                         }
1214
1215                 /* can stall some OUT transfers */
1216                 } else if (dev->setup_can_stall) {
1217                         VDEBUG(dev, "ep0out stall\n");
1218                         (void) usb_ep_set_halt (dev->gadget->ep0);
1219                         retval = -EL2HLT;
1220                         dev->state = STATE_DEV_CONNECTED;
1221                 } else {
1222                         DBG(dev, "bogus ep0out stall!\n");
1223                 }
1224         } else
1225                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1226
1227         spin_unlock_irq (&dev->lock);
1228         return retval;
1229 }
1230
1231 static int
1232 ep0_fasync (int f, struct file *fd, int on)
1233 {
1234         struct dev_data         *dev = fd->private_data;
1235         // caller must F_SETOWN before signal delivery happens
1236         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1237         return fasync_helper (f, fd, on, &dev->fasync);
1238 }
1239
1240 static struct usb_gadget_driver gadgetfs_driver;
1241
1242 static int
1243 dev_release (struct inode *inode, struct file *fd)
1244 {
1245         struct dev_data         *dev = fd->private_data;
1246
1247         /* closing ep0 === shutdown all */
1248
1249         usb_gadget_unregister_driver (&gadgetfs_driver);
1250
1251         /* at this point "good" hardware has disconnected the
1252          * device from USB; the host won't see it any more.
1253          * alternatively, all host requests will time out.
1254          */
1255
1256         fasync_helper (-1, fd, 0, &dev->fasync);
1257         kfree (dev->buf);
1258         dev->buf = NULL;
1259         put_dev (dev);
1260
1261         /* other endpoints were all decoupled from this device */
1262         spin_lock_irq(&dev->lock);
1263         dev->state = STATE_DEV_DISABLED;
1264         spin_unlock_irq(&dev->lock);
1265         return 0;
1266 }
1267
1268 static unsigned int
1269 ep0_poll (struct file *fd, poll_table *wait)
1270 {
1271        struct dev_data         *dev = fd->private_data;
1272        int                     mask = 0;
1273
1274        poll_wait(fd, &dev->wait, wait);
1275
1276        spin_lock_irq (&dev->lock);
1277
1278        /* report fd mode change before acting on it */
1279        if (dev->setup_abort) {
1280                dev->setup_abort = 0;
1281                mask = POLLHUP;
1282                goto out;
1283        }
1284
1285        if (dev->state == STATE_DEV_SETUP) {
1286                if (dev->setup_in || dev->setup_can_stall)
1287                        mask = POLLOUT;
1288        } else {
1289                if (dev->ev_next != 0)
1290                        mask = POLLIN;
1291        }
1292 out:
1293        spin_unlock_irq(&dev->lock);
1294        return mask;
1295 }
1296
1297 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1298 {
1299         struct dev_data         *dev = fd->private_data;
1300         struct usb_gadget       *gadget = dev->gadget;
1301         long ret = -ENOTTY;
1302
1303         if (gadget->ops->ioctl) {
1304                 lock_kernel();
1305                 ret = gadget->ops->ioctl (gadget, code, value);
1306                 unlock_kernel();
1307         }
1308         return ret;
1309 }
1310
1311 /* used after device configuration */
1312 static const struct file_operations ep0_io_operations = {
1313         .owner =        THIS_MODULE,
1314         .llseek =       no_llseek,
1315
1316         .read =         ep0_read,
1317         .write =        ep0_write,
1318         .fasync =       ep0_fasync,
1319         .poll =         ep0_poll,
1320         .unlocked_ioctl =       dev_ioctl,
1321         .release =      dev_release,
1322 };
1323
1324 /*----------------------------------------------------------------------*/
1325
1326 /* The in-kernel gadget driver handles most ep0 issues, in particular
1327  * enumerating the single configuration (as provided from user space).
1328  *
1329  * Unrecognized ep0 requests may be handled in user space.
1330  */
1331
1332 #ifdef  CONFIG_USB_GADGET_DUALSPEED
1333 static void make_qualifier (struct dev_data *dev)
1334 {
1335         struct usb_qualifier_descriptor         qual;
1336         struct usb_device_descriptor            *desc;
1337
1338         qual.bLength = sizeof qual;
1339         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1340         qual.bcdUSB = __constant_cpu_to_le16 (0x0200);
1341
1342         desc = dev->dev;
1343         qual.bDeviceClass = desc->bDeviceClass;
1344         qual.bDeviceSubClass = desc->bDeviceSubClass;
1345         qual.bDeviceProtocol = desc->bDeviceProtocol;
1346
1347         /* assumes ep0 uses the same value for both speeds ... */
1348         qual.bMaxPacketSize0 = desc->bMaxPacketSize0;
1349
1350         qual.bNumConfigurations = 1;
1351         qual.bRESERVED = 0;
1352
1353         memcpy (dev->rbuf, &qual, sizeof qual);
1354 }
1355 #endif
1356
1357 static int
1358 config_buf (struct dev_data *dev, u8 type, unsigned index)
1359 {
1360         int             len;
1361         int             hs = 0;
1362
1363         /* only one configuration */
1364         if (index > 0)
1365                 return -EINVAL;
1366
1367         if (gadget_is_dualspeed(dev->gadget)) {
1368                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1369                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1370                         hs = !hs;
1371         }
1372         if (hs) {
1373                 dev->req->buf = dev->hs_config;
1374                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1375         } else {
1376                 dev->req->buf = dev->config;
1377                 len = le16_to_cpu(dev->config->wTotalLength);
1378         }
1379         ((u8 *)dev->req->buf) [1] = type;
1380         return len;
1381 }
1382
1383 static int
1384 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1385 {
1386         struct dev_data                 *dev = get_gadget_data (gadget);
1387         struct usb_request              *req = dev->req;
1388         int                             value = -EOPNOTSUPP;
1389         struct usb_gadgetfs_event       *event;
1390         u16                             w_value = le16_to_cpu(ctrl->wValue);
1391         u16                             w_length = le16_to_cpu(ctrl->wLength);
1392
1393         spin_lock (&dev->lock);
1394         dev->setup_abort = 0;
1395         if (dev->state == STATE_DEV_UNCONNECTED) {
1396                 if (gadget_is_dualspeed(gadget)
1397                                 && gadget->speed == USB_SPEED_HIGH
1398                                 && dev->hs_config == NULL) {
1399                         spin_unlock(&dev->lock);
1400                         ERROR (dev, "no high speed config??\n");
1401                         return -EINVAL;
1402                 }
1403
1404                 dev->state = STATE_DEV_CONNECTED;
1405                 dev->dev->bMaxPacketSize0 = gadget->ep0->maxpacket;
1406
1407                 INFO (dev, "connected\n");
1408                 event = next_event (dev, GADGETFS_CONNECT);
1409                 event->u.speed = gadget->speed;
1410                 ep0_readable (dev);
1411
1412         /* host may have given up waiting for response.  we can miss control
1413          * requests handled lower down (device/endpoint status and features);
1414          * then ep0_{read,write} will report the wrong status. controller
1415          * driver will have aborted pending i/o.
1416          */
1417         } else if (dev->state == STATE_DEV_SETUP)
1418                 dev->setup_abort = 1;
1419
1420         req->buf = dev->rbuf;
1421         req->dma = DMA_ADDR_INVALID;
1422         req->context = NULL;
1423         value = -EOPNOTSUPP;
1424         switch (ctrl->bRequest) {
1425
1426         case USB_REQ_GET_DESCRIPTOR:
1427                 if (ctrl->bRequestType != USB_DIR_IN)
1428                         goto unrecognized;
1429                 switch (w_value >> 8) {
1430
1431                 case USB_DT_DEVICE:
1432                         value = min (w_length, (u16) sizeof *dev->dev);
1433                         req->buf = dev->dev;
1434                         break;
1435 #ifdef  CONFIG_USB_GADGET_DUALSPEED
1436                 case USB_DT_DEVICE_QUALIFIER:
1437                         if (!dev->hs_config)
1438                                 break;
1439                         value = min (w_length, (u16)
1440                                 sizeof (struct usb_qualifier_descriptor));
1441                         make_qualifier (dev);
1442                         break;
1443                 case USB_DT_OTHER_SPEED_CONFIG:
1444                         // FALLTHROUGH
1445 #endif
1446                 case USB_DT_CONFIG:
1447                         value = config_buf (dev,
1448                                         w_value >> 8,
1449                                         w_value & 0xff);
1450                         if (value >= 0)
1451                                 value = min (w_length, (u16) value);
1452                         break;
1453                 case USB_DT_STRING:
1454                         goto unrecognized;
1455
1456                 default:                // all others are errors
1457                         break;
1458                 }
1459                 break;
1460
1461         /* currently one config, two speeds */
1462         case USB_REQ_SET_CONFIGURATION:
1463                 if (ctrl->bRequestType != 0)
1464                         goto unrecognized;
1465                 if (0 == (u8) w_value) {
1466                         value = 0;
1467                         dev->current_config = 0;
1468                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1469                         // user mode expected to disable endpoints
1470                 } else {
1471                         u8      config, power;
1472
1473                         if (gadget_is_dualspeed(gadget)
1474                                         && gadget->speed == USB_SPEED_HIGH) {
1475                                 config = dev->hs_config->bConfigurationValue;
1476                                 power = dev->hs_config->bMaxPower;
1477                         } else {
1478                                 config = dev->config->bConfigurationValue;
1479                                 power = dev->config->bMaxPower;
1480                         }
1481
1482                         if (config == (u8) w_value) {
1483                                 value = 0;
1484                                 dev->current_config = config;
1485                                 usb_gadget_vbus_draw(gadget, 2 * power);
1486                         }
1487                 }
1488
1489                 /* report SET_CONFIGURATION like any other control request,
1490                  * except that usermode may not stall this.  the next
1491                  * request mustn't be allowed start until this finishes:
1492                  * endpoints and threads set up, etc.
1493                  *
1494                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1495                  * has bad/racey automagic that prevents synchronizing here.
1496                  * even kernel mode drivers often miss them.
1497                  */
1498                 if (value == 0) {
1499                         INFO (dev, "configuration #%d\n", dev->current_config);
1500                         if (dev->usermode_setup) {
1501                                 dev->setup_can_stall = 0;
1502                                 goto delegate;
1503                         }
1504                 }
1505                 break;
1506
1507 #ifndef CONFIG_USB_GADGET_PXA25X
1508         /* PXA automagically handles this request too */
1509         case USB_REQ_GET_CONFIGURATION:
1510                 if (ctrl->bRequestType != 0x80)
1511                         goto unrecognized;
1512                 *(u8 *)req->buf = dev->current_config;
1513                 value = min (w_length, (u16) 1);
1514                 break;
1515 #endif
1516
1517         default:
1518 unrecognized:
1519                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1520                         dev->usermode_setup ? "delegate" : "fail",
1521                         ctrl->bRequestType, ctrl->bRequest,
1522                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1523
1524                 /* if there's an ep0 reader, don't stall */
1525                 if (dev->usermode_setup) {
1526                         dev->setup_can_stall = 1;
1527 delegate:
1528                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1529                                                 ? 1 : 0;
1530                         dev->setup_wLength = w_length;
1531                         dev->setup_out_ready = 0;
1532                         dev->setup_out_error = 0;
1533                         value = 0;
1534
1535                         /* read DATA stage for OUT right away */
1536                         if (unlikely (!dev->setup_in && w_length)) {
1537                                 value = setup_req (gadget->ep0, dev->req,
1538                                                         w_length);
1539                                 if (value < 0)
1540                                         break;
1541                                 value = usb_ep_queue (gadget->ep0, dev->req,
1542                                                         GFP_ATOMIC);
1543                                 if (value < 0) {
1544                                         clean_req (gadget->ep0, dev->req);
1545                                         break;
1546                                 }
1547
1548                                 /* we can't currently stall these */
1549                                 dev->setup_can_stall = 0;
1550                         }
1551
1552                         /* state changes when reader collects event */
1553                         event = next_event (dev, GADGETFS_SETUP);
1554                         event->u.setup = *ctrl;
1555                         ep0_readable (dev);
1556                         spin_unlock (&dev->lock);
1557                         return 0;
1558                 }
1559         }
1560
1561         /* proceed with data transfer and status phases? */
1562         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1563                 req->length = value;
1564                 req->zero = value < w_length;
1565                 value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
1566                 if (value < 0) {
1567                         DBG (dev, "ep_queue --> %d\n", value);
1568                         req->status = 0;
1569                 }
1570         }
1571
1572         /* device stalls when value < 0 */
1573         spin_unlock (&dev->lock);
1574         return value;
1575 }
1576
1577 static void destroy_ep_files (struct dev_data *dev)
1578 {
1579         struct list_head        *entry, *tmp;
1580
1581         DBG (dev, "%s %d\n", __func__, dev->state);
1582
1583         /* dev->state must prevent interference */
1584 restart:
1585         spin_lock_irq (&dev->lock);
1586         list_for_each_safe (entry, tmp, &dev->epfiles) {
1587                 struct ep_data  *ep;
1588                 struct inode    *parent;
1589                 struct dentry   *dentry;
1590
1591                 /* break link to FS */
1592                 ep = list_entry (entry, struct ep_data, epfiles);
1593                 list_del_init (&ep->epfiles);
1594                 dentry = ep->dentry;
1595                 ep->dentry = NULL;
1596                 parent = dentry->d_parent->d_inode;
1597
1598                 /* break link to controller */
1599                 if (ep->state == STATE_EP_ENABLED)
1600                         (void) usb_ep_disable (ep->ep);
1601                 ep->state = STATE_EP_UNBOUND;
1602                 usb_ep_free_request (ep->ep, ep->req);
1603                 ep->ep = NULL;
1604                 wake_up (&ep->wait);
1605                 put_ep (ep);
1606
1607                 spin_unlock_irq (&dev->lock);
1608
1609                 /* break link to dcache */
1610                 mutex_lock (&parent->i_mutex);
1611                 d_delete (dentry);
1612                 dput (dentry);
1613                 mutex_unlock (&parent->i_mutex);
1614
1615                 /* fds may still be open */
1616                 goto restart;
1617         }
1618         spin_unlock_irq (&dev->lock);
1619 }
1620
1621
1622 static struct inode *
1623 gadgetfs_create_file (struct super_block *sb, char const *name,
1624                 void *data, const struct file_operations *fops,
1625                 struct dentry **dentry_p);
1626
1627 static int activate_ep_files (struct dev_data *dev)
1628 {
1629         struct usb_ep   *ep;
1630         struct ep_data  *data;
1631
1632         gadget_for_each_ep (ep, dev->gadget) {
1633
1634                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1635                 if (!data)
1636                         goto enomem0;
1637                 data->state = STATE_EP_DISABLED;
1638                 init_MUTEX (&data->lock);
1639                 init_waitqueue_head (&data->wait);
1640
1641                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1642                 atomic_set (&data->count, 1);
1643                 data->dev = dev;
1644                 get_dev (dev);
1645
1646                 data->ep = ep;
1647                 ep->driver_data = data;
1648
1649                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1650                 if (!data->req)
1651                         goto enomem1;
1652
1653                 data->inode = gadgetfs_create_file (dev->sb, data->name,
1654                                 data, &ep_config_operations,
1655                                 &data->dentry);
1656                 if (!data->inode)
1657                         goto enomem2;
1658                 list_add_tail (&data->epfiles, &dev->epfiles);
1659         }
1660         return 0;
1661
1662 enomem2:
1663         usb_ep_free_request (ep, data->req);
1664 enomem1:
1665         put_dev (dev);
1666         kfree (data);
1667 enomem0:
1668         DBG (dev, "%s enomem\n", __func__);
1669         destroy_ep_files (dev);
1670         return -ENOMEM;
1671 }
1672
1673 static void
1674 gadgetfs_unbind (struct usb_gadget *gadget)
1675 {
1676         struct dev_data         *dev = get_gadget_data (gadget);
1677
1678         DBG (dev, "%s\n", __func__);
1679
1680         spin_lock_irq (&dev->lock);
1681         dev->state = STATE_DEV_UNBOUND;
1682         spin_unlock_irq (&dev->lock);
1683
1684         destroy_ep_files (dev);
1685         gadget->ep0->driver_data = NULL;
1686         set_gadget_data (gadget, NULL);
1687
1688         /* we've already been disconnected ... no i/o is active */
1689         if (dev->req)
1690                 usb_ep_free_request (gadget->ep0, dev->req);
1691         DBG (dev, "%s done\n", __func__);
1692         put_dev (dev);
1693 }
1694
1695 static struct dev_data          *the_device;
1696
1697 static int
1698 gadgetfs_bind (struct usb_gadget *gadget)
1699 {
1700         struct dev_data         *dev = the_device;
1701
1702         if (!dev)
1703                 return -ESRCH;
1704         if (0 != strcmp (CHIP, gadget->name)) {
1705                 pr_err("%s expected %s controller not %s\n",
1706                         shortname, CHIP, gadget->name);
1707                 return -ENODEV;
1708         }
1709
1710         set_gadget_data (gadget, dev);
1711         dev->gadget = gadget;
1712         gadget->ep0->driver_data = dev;
1713         dev->dev->bMaxPacketSize0 = gadget->ep0->maxpacket;
1714
1715         /* preallocate control response and buffer */
1716         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1717         if (!dev->req)
1718                 goto enomem;
1719         dev->req->context = NULL;
1720         dev->req->complete = epio_complete;
1721
1722         if (activate_ep_files (dev) < 0)
1723                 goto enomem;
1724
1725         INFO (dev, "bound to %s driver\n", gadget->name);
1726         spin_lock_irq(&dev->lock);
1727         dev->state = STATE_DEV_UNCONNECTED;
1728         spin_unlock_irq(&dev->lock);
1729         get_dev (dev);
1730         return 0;
1731
1732 enomem:
1733         gadgetfs_unbind (gadget);
1734         return -ENOMEM;
1735 }
1736
1737 static void
1738 gadgetfs_disconnect (struct usb_gadget *gadget)
1739 {
1740         struct dev_data         *dev = get_gadget_data (gadget);
1741
1742         spin_lock (&dev->lock);
1743         if (dev->state == STATE_DEV_UNCONNECTED)
1744                 goto exit;
1745         dev->state = STATE_DEV_UNCONNECTED;
1746
1747         INFO (dev, "disconnected\n");
1748         next_event (dev, GADGETFS_DISCONNECT);
1749         ep0_readable (dev);
1750 exit:
1751         spin_unlock (&dev->lock);
1752 }
1753
1754 static void
1755 gadgetfs_suspend (struct usb_gadget *gadget)
1756 {
1757         struct dev_data         *dev = get_gadget_data (gadget);
1758
1759         INFO (dev, "suspended from state %d\n", dev->state);
1760         spin_lock (&dev->lock);
1761         switch (dev->state) {
1762         case STATE_DEV_SETUP:           // VERY odd... host died??
1763         case STATE_DEV_CONNECTED:
1764         case STATE_DEV_UNCONNECTED:
1765                 next_event (dev, GADGETFS_SUSPEND);
1766                 ep0_readable (dev);
1767                 /* FALLTHROUGH */
1768         default:
1769                 break;
1770         }
1771         spin_unlock (&dev->lock);
1772 }
1773
1774 static struct usb_gadget_driver gadgetfs_driver = {
1775 #ifdef  CONFIG_USB_GADGET_DUALSPEED
1776         .speed          = USB_SPEED_HIGH,
1777 #else
1778         .speed          = USB_SPEED_FULL,
1779 #endif
1780         .function       = (char *) driver_desc,
1781         .bind           = gadgetfs_bind,
1782         .unbind         = gadgetfs_unbind,
1783         .setup          = gadgetfs_setup,
1784         .disconnect     = gadgetfs_disconnect,
1785         .suspend        = gadgetfs_suspend,
1786
1787         .driver = {
1788                 .name           = (char *) shortname,
1789         },
1790 };
1791
1792 /*----------------------------------------------------------------------*/
1793
1794 static void gadgetfs_nop(struct usb_gadget *arg) { }
1795
1796 static int gadgetfs_probe (struct usb_gadget *gadget)
1797 {
1798         CHIP = gadget->name;
1799         return -EISNAM;
1800 }
1801
1802 static struct usb_gadget_driver probe_driver = {
1803         .speed          = USB_SPEED_HIGH,
1804         .bind           = gadgetfs_probe,
1805         .unbind         = gadgetfs_nop,
1806         .setup          = (void *)gadgetfs_nop,
1807         .disconnect     = gadgetfs_nop,
1808         .driver = {
1809                 .name           = "nop",
1810         },
1811 };
1812
1813
1814 /* DEVICE INITIALIZATION
1815  *
1816  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1817  *     status = write (fd, descriptors, sizeof descriptors)
1818  *
1819  * That write establishes the device configuration, so the kernel can
1820  * bind to the controller ... guaranteeing it can handle enumeration
1821  * at all necessary speeds.  Descriptor order is:
1822  *
1823  * . message tag (u32, host order) ... for now, must be zero; it
1824  *      would change to support features like multi-config devices
1825  * . full/low speed config ... all wTotalLength bytes (with interface,
1826  *      class, altsetting, endpoint, and other descriptors)
1827  * . high speed config ... all descriptors, for high speed operation;
1828  *      this one's optional except for high-speed hardware
1829  * . device descriptor
1830  *
1831  * Endpoints are not yet enabled. Drivers must wait until device
1832  * configuration and interface altsetting changes create
1833  * the need to configure (or unconfigure) them.
1834  *
1835  * After initialization, the device stays active for as long as that
1836  * $CHIP file is open.  Events must then be read from that descriptor,
1837  * such as configuration notifications.
1838  */
1839
1840 static int is_valid_config (struct usb_config_descriptor *config)
1841 {
1842         return config->bDescriptorType == USB_DT_CONFIG
1843                 && config->bLength == USB_DT_CONFIG_SIZE
1844                 && config->bConfigurationValue != 0
1845                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1846                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1847         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1848         /* FIXME check lengths: walk to end */
1849 }
1850
1851 static ssize_t
1852 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1853 {
1854         struct dev_data         *dev = fd->private_data;
1855         ssize_t                 value = len, length = len;
1856         unsigned                total;
1857         u32                     tag;
1858         char                    *kbuf;
1859
1860         if (len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4))
1861                 return -EINVAL;
1862
1863         /* we might need to change message format someday */
1864         if (copy_from_user (&tag, buf, 4))
1865                 return -EFAULT;
1866         if (tag != 0)
1867                 return -EINVAL;
1868         buf += 4;
1869         length -= 4;
1870
1871         kbuf = kmalloc (length, GFP_KERNEL);
1872         if (!kbuf)
1873                 return -ENOMEM;
1874         if (copy_from_user (kbuf, buf, length)) {
1875                 kfree (kbuf);
1876                 return -EFAULT;
1877         }
1878
1879         spin_lock_irq (&dev->lock);
1880         value = -EINVAL;
1881         if (dev->buf)
1882                 goto fail;
1883         dev->buf = kbuf;
1884
1885         /* full or low speed config */
1886         dev->config = (void *) kbuf;
1887         total = le16_to_cpu(dev->config->wTotalLength);
1888         if (!is_valid_config (dev->config) || total >= length)
1889                 goto fail;
1890         kbuf += total;
1891         length -= total;
1892
1893         /* optional high speed config */
1894         if (kbuf [1] == USB_DT_CONFIG) {
1895                 dev->hs_config = (void *) kbuf;
1896                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1897                 if (!is_valid_config (dev->hs_config) || total >= length)
1898                         goto fail;
1899                 kbuf += total;
1900                 length -= total;
1901         }
1902
1903         /* could support multiple configs, using another encoding! */
1904
1905         /* device descriptor (tweaked for paranoia) */
1906         if (length != USB_DT_DEVICE_SIZE)
1907                 goto fail;
1908         dev->dev = (void *)kbuf;
1909         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1910                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1911                         || dev->dev->bNumConfigurations != 1)
1912                 goto fail;
1913         dev->dev->bNumConfigurations = 1;
1914         dev->dev->bcdUSB = __constant_cpu_to_le16 (0x0200);
1915
1916         /* triggers gadgetfs_bind(); then we can enumerate. */
1917         spin_unlock_irq (&dev->lock);
1918         value = usb_gadget_register_driver (&gadgetfs_driver);
1919         if (value != 0) {
1920                 kfree (dev->buf);
1921                 dev->buf = NULL;
1922         } else {
1923                 /* at this point "good" hardware has for the first time
1924                  * let the USB the host see us.  alternatively, if users
1925                  * unplug/replug that will clear all the error state.
1926                  *
1927                  * note:  everything running before here was guaranteed
1928                  * to choke driver model style diagnostics.  from here
1929                  * on, they can work ... except in cleanup paths that
1930                  * kick in after the ep0 descriptor is closed.
1931                  */
1932                 fd->f_op = &ep0_io_operations;
1933                 value = len;
1934         }
1935         return value;
1936
1937 fail:
1938         spin_unlock_irq (&dev->lock);
1939         pr_debug ("%s: %s fail %Zd, %p\n", shortname, __func__, value, dev);
1940         kfree (dev->buf);
1941         dev->buf = NULL;
1942         return value;
1943 }
1944
1945 static int
1946 dev_open (struct inode *inode, struct file *fd)
1947 {
1948         struct dev_data         *dev = inode->i_private;
1949         int                     value = -EBUSY;
1950
1951         spin_lock_irq(&dev->lock);
1952         if (dev->state == STATE_DEV_DISABLED) {
1953                 dev->ev_next = 0;
1954                 dev->state = STATE_DEV_OPENED;
1955                 fd->private_data = dev;
1956                 get_dev (dev);
1957                 value = 0;
1958         }
1959         spin_unlock_irq(&dev->lock);
1960         return value;
1961 }
1962
1963 static const struct file_operations dev_init_operations = {
1964         .owner =        THIS_MODULE,
1965         .llseek =       no_llseek,
1966
1967         .open =         dev_open,
1968         .write =        dev_config,
1969         .fasync =       ep0_fasync,
1970         .unlocked_ioctl = dev_ioctl,
1971         .release =      dev_release,
1972 };
1973
1974 /*----------------------------------------------------------------------*/
1975
1976 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1977  *
1978  * Mounting the filesystem creates a controller file, used first for
1979  * device configuration then later for event monitoring.
1980  */
1981
1982
1983 /* FIXME PAM etc could set this security policy without mount options
1984  * if epfiles inherited ownership and permissons from ep0 ...
1985  */
1986
1987 static unsigned default_uid;
1988 static unsigned default_gid;
1989 static unsigned default_perm = S_IRUSR | S_IWUSR;
1990
1991 module_param (default_uid, uint, 0644);
1992 module_param (default_gid, uint, 0644);
1993 module_param (default_perm, uint, 0644);
1994
1995
1996 static struct inode *
1997 gadgetfs_make_inode (struct super_block *sb,
1998                 void *data, const struct file_operations *fops,
1999                 int mode)
2000 {
2001         struct inode *inode = new_inode (sb);
2002
2003         if (inode) {
2004                 inode->i_mode = mode;
2005                 inode->i_uid = default_uid;
2006                 inode->i_gid = default_gid;
2007                 inode->i_blocks = 0;
2008                 inode->i_atime = inode->i_mtime = inode->i_ctime
2009                                 = CURRENT_TIME;
2010                 inode->i_private = data;
2011                 inode->i_fop = fops;
2012         }
2013         return inode;
2014 }
2015
2016 /* creates in fs root directory, so non-renamable and non-linkable.
2017  * so inode and dentry are paired, until device reconfig.
2018  */
2019 static struct inode *
2020 gadgetfs_create_file (struct super_block *sb, char const *name,
2021                 void *data, const struct file_operations *fops,
2022                 struct dentry **dentry_p)
2023 {
2024         struct dentry   *dentry;
2025         struct inode    *inode;
2026
2027         dentry = d_alloc_name(sb->s_root, name);
2028         if (!dentry)
2029                 return NULL;
2030
2031         inode = gadgetfs_make_inode (sb, data, fops,
2032                         S_IFREG | (default_perm & S_IRWXUGO));
2033         if (!inode) {
2034                 dput(dentry);
2035                 return NULL;
2036         }
2037         d_add (dentry, inode);
2038         *dentry_p = dentry;
2039         return inode;
2040 }
2041
2042 static struct super_operations gadget_fs_operations = {
2043         .statfs =       simple_statfs,
2044         .drop_inode =   generic_delete_inode,
2045 };
2046
2047 static int
2048 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
2049 {
2050         struct inode    *inode;
2051         struct dentry   *d;
2052         struct dev_data *dev;
2053
2054         if (the_device)
2055                 return -ESRCH;
2056
2057         /* fake probe to determine $CHIP */
2058         (void) usb_gadget_register_driver (&probe_driver);
2059         if (!CHIP)
2060                 return -ENODEV;
2061
2062         /* superblock */
2063         sb->s_blocksize = PAGE_CACHE_SIZE;
2064         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2065         sb->s_magic = GADGETFS_MAGIC;
2066         sb->s_op = &gadget_fs_operations;
2067         sb->s_time_gran = 1;
2068
2069         /* root inode */
2070         inode = gadgetfs_make_inode (sb,
2071                         NULL, &simple_dir_operations,
2072                         S_IFDIR | S_IRUGO | S_IXUGO);
2073         if (!inode)
2074                 goto enomem0;
2075         inode->i_op = &simple_dir_inode_operations;
2076         if (!(d = d_alloc_root (inode)))
2077                 goto enomem1;
2078         sb->s_root = d;
2079
2080         /* the ep0 file is named after the controller we expect;
2081          * user mode code can use it for sanity checks, like we do.
2082          */
2083         dev = dev_new ();
2084         if (!dev)
2085                 goto enomem2;
2086
2087         dev->sb = sb;
2088         if (!gadgetfs_create_file (sb, CHIP,
2089                                 dev, &dev_init_operations,
2090                                 &dev->dentry))
2091                 goto enomem3;
2092
2093         /* other endpoint files are available after hardware setup,
2094          * from binding to a controller.
2095          */
2096         the_device = dev;
2097         return 0;
2098
2099 enomem3:
2100         put_dev (dev);
2101 enomem2:
2102         dput (d);
2103 enomem1:
2104         iput (inode);
2105 enomem0:
2106         return -ENOMEM;
2107 }
2108
2109 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2110 static int
2111 gadgetfs_get_sb (struct file_system_type *t, int flags,
2112                 const char *path, void *opts, struct vfsmount *mnt)
2113 {
2114         return get_sb_single (t, flags, opts, gadgetfs_fill_super, mnt);
2115 }
2116
2117 static void
2118 gadgetfs_kill_sb (struct super_block *sb)
2119 {
2120         kill_litter_super (sb);
2121         if (the_device) {
2122                 put_dev (the_device);
2123                 the_device = NULL;
2124         }
2125 }
2126
2127 /*----------------------------------------------------------------------*/
2128
2129 static struct file_system_type gadgetfs_type = {
2130         .owner          = THIS_MODULE,
2131         .name           = shortname,
2132         .get_sb         = gadgetfs_get_sb,
2133         .kill_sb        = gadgetfs_kill_sb,
2134 };
2135
2136 /*----------------------------------------------------------------------*/
2137
2138 static int __init init (void)
2139 {
2140         int status;
2141
2142         status = register_filesystem (&gadgetfs_type);
2143         if (status == 0)
2144                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2145                         shortname, driver_desc);
2146         return status;
2147 }
2148 module_init (init);
2149
2150 static void __exit cleanup (void)
2151 {
2152         pr_debug ("unregister %s\n", shortname);
2153         unregister_filesystem (&gadgetfs_type);
2154 }
2155 module_exit (cleanup);
2156