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 #include <linux/mmu_context.h>
  28 #include <linux/aio.h>
  29
  30 #include <linux/device.h>
  31 #include <linux/moduleparam.h>
  32
  33 #include <linux/usb/gadgetfs.h>
  34 #include <linux/usb/gadget.h>
  35
  36
  37 /*
  38  * The gadgetfs API maps each endpoint to a file descriptor so that you
  39  * can use standard synchronous read/write calls for I/O.  There's some
  40  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  41  * drivers show how this works in practice.  You can also use AIO to
  42  * eliminate I/O gaps between requests, to help when streaming data.
  43  *
  44  * Key parts that must be USB-specific are protocols defining how the
  45  * read/write operations relate to the hardware state machines.  There
  46  * are two types of files.  One type is for the device, implementing ep0.
  47  * The other type is for each IN or OUT endpoint.  In both cases, the
  48  * user mode driver must configure the hardware before using it.
  49  *
  50  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  51  *   (by writing configuration and device descriptors).  Afterwards it
  52  *   may serve as a source of device events, used to handle all control
  53  *   requests other than basic enumeration.
  54  *
  55  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  56  *   called when each /dev/gadget/ep* file is configured (by writing
  57  *   endpoint descriptors).  Afterwards these files are used to write()
  58  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  59  *   direction" request is issued (like reading an IN endpoint).
  60  *
  61  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  62  * not possible on all hardware.  For example, precise fault handling with
  63  * respect to data left in endpoint fifos after aborted operations; or
  64  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  65  */
  66
  67 #define DRIVER_DESC     "USB Gadget filesystem"
  68 #define DRIVER_VERSION  "24 Aug 2004"
  69
  70 static const char driver_desc [] = DRIVER_DESC;
  71 static const char shortname [] = "gadgetfs";
  72
  73 MODULE_DESCRIPTION (DRIVER_DESC);
  74 MODULE_AUTHOR ("David Brownell");
  75 MODULE_LICENSE ("GPL");
  76
  77
  78 /*----------------------------------------------------------------------*/
  79
  80 #define GADGETFS_MAGIC          0xaee71ee7
  81
  82 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  83 enum ep0_state {
  84         /* DISBLED is the initial state.
  85          */
  86         STATE_DEV_DISABLED = 0,
  87
  88         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  89          * ep0/device i/o modes and binding to the controller.  Driver
  90          * must always write descriptors to initialize the device, then
  91          * the device becomes UNCONNECTED until enumeration.
  92          */
  93         STATE_DEV_OPENED,
  94
  95         /* From then on, ep0 fd is in either of two basic modes:
  96          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
  97          * - SETUP: read/write will transfer control data and succeed;
  98          *   or if "wrong direction", performs protocol stall
  99          */
 100         STATE_DEV_UNCONNECTED,
 101         STATE_DEV_CONNECTED,
 102         STATE_DEV_SETUP,
 103
 104         /* UNBOUND means the driver closed ep0, so the device won't be
 105          * accessible again (DEV_DISABLED) until all fds are closed.
 106          */
 107         STATE_DEV_UNBOUND,
 108 };
 109
 110 /* enough for the whole queue: most events invalidate others */
 111 #define N_EVENT                 5
 112
 113 struct dev_data {
 114         spinlock_t                      lock;
 115         atomic_t                        count;
 116         enum ep0_state                  state;          /* P: lock */
 117         struct usb_gadgetfs_event       event [N_EVENT];
 118         unsigned                        ev_next;
 119         struct fasync_struct            *fasync;
 120         u8                              current_config;
 121
 122         /* drivers reading ep0 MUST handle control requests (SETUP)
 123          * reported that way; else the host will time out.
 124          */
 125         unsigned                        usermode_setup : 1,
 126                                         setup_in : 1,
 127                                         setup_can_stall : 1,
 128                                         setup_out_ready : 1,
 129                                         setup_out_error : 1,
 130                                         setup_abort : 1;
 131         unsigned                        setup_wLength;
 132
 133         /* the rest is basically write-once */
 134         struct usb_config_descriptor    *config, *hs_config;
 135         struct usb_device_descriptor    *dev;
 136         struct usb_request              *req;
 137         struct usb_gadget               *gadget;
 138         struct list_head                epfiles;
 139         void                            *buf;
 140         wait_queue_head_t               wait;
 141         struct super_block              *sb;
 142         struct dentry                   *dentry;
 143
 144         /* except this scratch i/o buffer for ep0 */
 145         u8                              rbuf [256];
 146 };
 147
 148 static inline void get_dev (struct dev_data *data)
 149 {
 150         atomic_inc (&data->count);
 151 }
 152
 153 static void put_dev (struct dev_data *data)
 154 {
 155         if (likely (!atomic_dec_and_test (&data->count)))
 156                 return;
 157         /* needs no more cleanup */
 158         BUG_ON (waitqueue_active (&data->wait));
 159         kfree (data);
 160 }
 161
 162 static struct dev_data *dev_new (void)
 163 {
 164         struct dev_data         *dev;
 165
 166         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 167         if (!dev)
 168                 return NULL;
 169         dev->state = STATE_DEV_DISABLED;
 170         atomic_set (&dev->count, 1);
 171         spin_lock_init (&dev->lock);
 172         INIT_LIST_HEAD (&dev->epfiles);
 173         init_waitqueue_head (&dev->wait);
 174         return dev;
 175 }
 176
 177 /*----------------------------------------------------------------------*/
 178
 179 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 180 enum ep_state {
 181         STATE_EP_DISABLED = 0,
 182         STATE_EP_READY,
 183         STATE_EP_ENABLED,
 184         STATE_EP_UNBOUND,
 185 };
 186
 187 struct ep_data {
 188         struct mutex                    lock;
 189         enum ep_state                   state;
 190         atomic_t                        count;
 191         struct dev_data                 *dev;
 192         /* must hold dev->lock before accessing ep or req */
 193         struct usb_ep                   *ep;
 194         struct usb_request              *req;
 195         ssize_t                         status;
 196         char                            name [16];
 197         struct usb_endpoint_descriptor  desc, hs_desc;
 198         struct list_head                epfiles;
 199         wait_queue_head_t               wait;
 200         struct dentry                   *dentry;
 201         struct inode                    *inode;
 202 };
 203
 204 static inline void get_ep (struct ep_data *data)
 205 {
 206         atomic_inc (&data->count);
 207 }
 208
 209 static void put_ep (struct ep_data *data)
 210 {
 211         if (likely (!atomic_dec_and_test (&data->count)))
 212                 return;
 213         put_dev (data->dev);
 214         /* needs no more cleanup */
 215         BUG_ON (!list_empty (&data->epfiles));
 216         BUG_ON (waitqueue_active (&data->wait));
 217         kfree (data);
 218 }
 219
 220 /*----------------------------------------------------------------------*/
 221
 222 /* most "how to use the hardware" policy choices are in userspace:
 223  * mapping endpoint roles (which the driver needs) to the capabilities
 224  * which the usb controller has.  most of those capabilities are exposed
 225  * implicitly, starting with the driver name and then endpoint names.
 226  */
 227
 228 static const char *CHIP;
 229
 230 /*----------------------------------------------------------------------*/
 231
 232 /* NOTE:  don't use dev_printk calls before binding to the gadget
 233  * at the end of ep0 configuration, or after unbind.
 234  */
 235
 236 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 237 #define xprintk(d,level,fmt,args...) \
 238         printk(level "%s: " fmt , shortname , ## args)
 239
 240 #ifdef DEBUG
 241 #define DBG(dev,fmt,args...) \
 242         xprintk(dev , KERN_DEBUG , fmt , ## args)
 243 #else
 244 #define DBG(dev,fmt,args...) \
 245         do { } while (0)
 246 #endif /* DEBUG */
 247
 248 #ifdef VERBOSE_DEBUG
 249 #define VDEBUG  DBG
 250 #else
 251 #define VDEBUG(dev,fmt,args...) \
 252         do { } while (0)
 253 #endif /* DEBUG */
 254
 255 #define ERROR(dev,fmt,args...) \
 256         xprintk(dev , KERN_ERR , fmt , ## args)
 257 #define INFO(dev,fmt,args...) \
 258         xprintk(dev , KERN_INFO , fmt , ## args)
 259
 260
 261 /*----------------------------------------------------------------------*/
 262
 263 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 264  *
 265  * After opening, configure non-control endpoints.  Then use normal
 266  * stream read() and write() requests; and maybe ioctl() to get more
 267  * precise FIFO status when recovering from cancellation.
 268  */
 269
 270 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 271 {
 272         struct ep_data  *epdata = ep->driver_data;
 273
 274         if (!req->context)
 275                 return;
 276         if (req->status)
 277                 epdata->status = req->status;
 278         else
 279                 epdata->status = req->actual;
 280         complete ((struct completion *)req->context);
 281 }
 282
 283 /* tasklock endpoint, returning when it's connected.
 284  * still need dev->lock to use epdata->ep.
 285  */
 286 static int
 287 get_ready_ep (unsigned f_flags, struct ep_data *epdata)
 288 {
 289         int     val;
 290
 291         if (f_flags & O_NONBLOCK) {
 292                 if (!mutex_trylock(&epdata->lock))
 293                         goto nonblock;
 294                 if (epdata->state != STATE_EP_ENABLED) {
 295                         mutex_unlock(&epdata->lock);
 296 nonblock:
 297                         val = -EAGAIN;
 298                 } else
 299                         val = 0;
 300                 return val;
 301         }
 302
 303         val = mutex_lock_interruptible(&epdata->lock);
 304         if (val < 0)
 305                 return val;
 306
 307         switch (epdata->state) {
 308         case STATE_EP_ENABLED:
 309                 break;
 310         // case STATE_EP_DISABLED:              /* "can't happen" */
 311         // case STATE_EP_READY:                 /* "can't happen" */
 312         default:                                /* error! */
 313                 pr_debug ("%s: ep %p not available, state %d\n",
 314                                 shortname, epdata, epdata->state);
 315                 // FALLTHROUGH
 316         case STATE_EP_UNBOUND:                  /* clean disconnect */
 317                 val = -ENODEV;
 318                 mutex_unlock(&epdata->lock);
 319         }
 320         return val;
 321 }
 322
 323 static ssize_t
 324 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 325 {
 326         DECLARE_COMPLETION_ONSTACK (done);
 327         int value;
 328
 329         spin_lock_irq (&epdata->dev->lock);
 330         if (likely (epdata->ep != NULL)) {
 331                 struct usb_request      *req = epdata->req;
 332
 333                 req->context = &done;
 334                 req->complete = epio_complete;
 335                 req->buf = buf;
 336                 req->length = len;
 337                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 338         } else
 339                 value = -ENODEV;
 340         spin_unlock_irq (&epdata->dev->lock);
 341
 342         if (likely (value == 0)) {
 343                 value = wait_event_interruptible (done.wait, done.done);
 344                 if (value != 0) {
 345                         spin_lock_irq (&epdata->dev->lock);
 346                         if (likely (epdata->ep != NULL)) {
 347                                 DBG (epdata->dev, "%s i/o interrupted\n",
 348                                                 epdata->name);
 349                                 usb_ep_dequeue (epdata->ep, epdata->req);
 350                                 spin_unlock_irq (&epdata->dev->lock);
 351
 352                                 wait_event (done.wait, done.done);
 353                                 if (epdata->status == -ECONNRESET)
 354                                         epdata->status = -EINTR;
 355                         } else {
 356                                 spin_unlock_irq (&epdata->dev->lock);
 357
 358                                 DBG (epdata->dev, "endpoint gone\n");
 359                                 epdata->status = -ENODEV;
 360                         }
 361                 }
 362                 return epdata->status;
 363         }
 364         return value;
 365 }
 366
 367
 368 /* handle a synchronous OUT bulk/intr/iso transfer */
 369 static ssize_t
 370 ep_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 371 {
 372         struct ep_data          *data = fd->private_data;
 373         void                    *kbuf;
 374         ssize_t                 value;
 375
 376         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
 377                 return value;
 378
 379         /* halt any endpoint by doing a "wrong direction" i/o call */
 380         if (usb_endpoint_dir_in(&data->desc)) {
 381                 if (usb_endpoint_xfer_isoc(&data->desc)) {
 382                         mutex_unlock(&data->lock);
 383                         return -EINVAL;
 384                 }
 385                 DBG (data->dev, "%s halt\n", data->name);
 386                 spin_lock_irq (&data->dev->lock);
 387                 if (likely (data->ep != NULL))
 388                         usb_ep_set_halt (data->ep);
 389                 spin_unlock_irq (&data->dev->lock);
 390                 mutex_unlock(&data->lock);
 391                 return -EBADMSG;
 392         }
 393
 394         /* FIXME readahead for O_NONBLOCK and poll(); careful with ZLPs */
 395
 396         value = -ENOMEM;
 397         kbuf = kmalloc (len, GFP_KERNEL);
 398         if (unlikely (!kbuf))
 399                 goto free1;
 400
 401         value = ep_io (data, kbuf, len);
 402         VDEBUG (data->dev, "%s read %zu OUT, status %d\n",
 403                 data->name, len, (int) value);
 404         if (value >= 0 && copy_to_user (buf, kbuf, value))
 405                 value = -EFAULT;
 406
 407 free1:
 408         mutex_unlock(&data->lock);
 409         kfree (kbuf);
 410         return value;
 411 }
 412
 413 /* handle a synchronous IN bulk/intr/iso transfer */
 414 static ssize_t
 415 ep_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 416 {
 417         struct ep_data          *data = fd->private_data;
 418         void                    *kbuf;
 419         ssize_t                 value;
 420
 421         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
 422                 return value;
 423
 424         /* halt any endpoint by doing a "wrong direction" i/o call */
 425         if (!usb_endpoint_dir_in(&data->desc)) {
 426                 if (usb_endpoint_xfer_isoc(&data->desc)) {
 427                         mutex_unlock(&data->lock);
 428                         return -EINVAL;
 429                 }
 430                 DBG (data->dev, "%s halt\n", data->name);
 431                 spin_lock_irq (&data->dev->lock);
 432                 if (likely (data->ep != NULL))
 433                         usb_ep_set_halt (data->ep);
 434                 spin_unlock_irq (&data->dev->lock);
 435                 mutex_unlock(&data->lock);
 436                 return -EBADMSG;
 437         }
 438
 439         /* FIXME writebehind for O_NONBLOCK and poll(), qlen = 1 */
 440
 441         value = -ENOMEM;
 442         kbuf = kmalloc (len, GFP_KERNEL);
 443         if (!kbuf)
 444                 goto free1;
 445         if (copy_from_user (kbuf, buf, len)) {
 446                 value = -EFAULT;
 447                 goto free1;
 448         }
 449
 450         value = ep_io (data, kbuf, len);
 451         VDEBUG (data->dev, "%s write %zu IN, status %d\n",
 452                 data->name, len, (int) value);
 453 free1:
 454         mutex_unlock(&data->lock);
 455         kfree (kbuf);
 456         return value;
 457 }
 458
 459 static int
 460 ep_release (struct inode *inode, struct file *fd)
 461 {
 462         struct ep_data          *data = fd->private_data;
 463         int value;
 464
 465         value = mutex_lock_interruptible(&data->lock);
 466         if (value < 0)
 467                 return value;
 468
 469         /* clean up if this can be reopened */
 470         if (data->state != STATE_EP_UNBOUND) {
 471                 data->state = STATE_EP_DISABLED;
 472                 data->desc.bDescriptorType = 0;
 473                 data->hs_desc.bDescriptorType = 0;
 474                 usb_ep_disable(data->ep);
 475         }
 476         mutex_unlock(&data->lock);
 477         put_ep (data);
 478         return 0;
 479 }
 480
 481 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 482 {
 483         struct ep_data          *data = fd->private_data;
 484         int                     status;
 485
 486         if ((status = get_ready_ep (fd->f_flags, data)) < 0)
 487                 return status;
 488
 489         spin_lock_irq (&data->dev->lock);
 490         if (likely (data->ep != NULL)) {
 491                 switch (code) {
 492                 case GADGETFS_FIFO_STATUS:
 493                         status = usb_ep_fifo_status (data->ep);
 494                         break;
 495                 case GADGETFS_FIFO_FLUSH:
 496                         usb_ep_fifo_flush (data->ep);
 497                         break;
 498                 case GADGETFS_CLEAR_HALT:
 499                         status = usb_ep_clear_halt (data->ep);
 500                         break;
 501                 default:
 502                         status = -ENOTTY;
 503                 }
 504         } else
 505                 status = -ENODEV;
 506         spin_unlock_irq (&data->dev->lock);
 507         mutex_unlock(&data->lock);
 508         return status;
 509 }
 510
 511 /*----------------------------------------------------------------------*/
 512
 513 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 514
 515 struct kiocb_priv {
 516         struct usb_request      *req;
 517         struct ep_data          *epdata;
 518         struct kiocb            *iocb;
 519         struct mm_struct        *mm;
 520         struct work_struct      work;
 521         void                    *buf;
 522         const struct iovec      *iv;
 523         unsigned long           nr_segs;
 524         unsigned                actual;
 525 };
 526
 527 static int ep_aio_cancel(struct kiocb *iocb, struct io_event *e)
 528 {
 529         struct kiocb_priv       *priv = iocb->private;
 530         struct ep_data          *epdata;
 531         int                     value;
 532
 533         local_irq_disable();
 534         epdata = priv->epdata;
 535         // spin_lock(&epdata->dev->lock);
 536         kiocbSetCancelled(iocb);
 537         if (likely(epdata && epdata->ep && priv->req))
 538                 value = usb_ep_dequeue (epdata->ep, priv->req);
 539         else
 540                 value = -EINVAL;
 541         // spin_unlock(&epdata->dev->lock);
 542         local_irq_enable();
 543
 544         aio_put_req(iocb);
 545         return value;
 546 }
 547
 548 static ssize_t ep_copy_to_user(struct kiocb_priv *priv)
 549 {
 550         ssize_t                 len, total;
 551         void                    *to_copy;
 552         int                     i;
 553
 554         /* copy stuff into user buffers */
 555         total = priv->actual;
 556         len = 0;
 557         to_copy = priv->buf;
 558         for (i=0; i < priv->nr_segs; i++) {
 559                 ssize_t this = min((ssize_t)(priv->iv[i].iov_len), total);
 560
 561                 if (copy_to_user(priv->iv[i].iov_base, to_copy, this)) {
 562                         if (len == 0)
 563                                 len = -EFAULT;
 564                         break;
 565                 }
 566
 567                 total -= this;
 568                 len += this;
 569                 to_copy += this;
 570                 if (total == 0)
 571                         break;
 572         }
 573
 574         return len;
 575 }
 576
 577 static void ep_user_copy_worker(struct work_struct *work)
 578 {
 579         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 580         struct mm_struct *mm = priv->mm;
 581         struct kiocb *iocb = priv->iocb;
 582         size_t ret;
 583
 584         use_mm(mm);
 585         ret = ep_copy_to_user(priv);
 586         unuse_mm(mm);
 587
 588         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 589         aio_complete(iocb, ret, ret);
 590
 591         kfree(priv->buf);
 592         kfree(priv);
 593 }
 594
 595 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 596 {
 597         struct kiocb            *iocb = req->context;
 598         struct kiocb_priv       *priv = iocb->private;
 599         struct ep_data          *epdata = priv->epdata;
 600
 601         /* lock against disconnect (and ideally, cancel) */
 602         spin_lock(&epdata->dev->lock);
 603         priv->req = NULL;
 604         priv->epdata = NULL;
 605
 606         /* if this was a write or a read returning no data then we
 607          * don't need to copy anything to userspace, so we can
 608          * complete the aio request immediately.
 609          */
 610         if (priv->iv == NULL || unlikely(req->actual == 0)) {
 611                 kfree(req->buf);
 612                 kfree(priv);
 613                 iocb->private = NULL;
 614                 /* aio_complete() reports bytes-transferred _and_ faults */
 615                 aio_complete(iocb, req->actual ? req->actual : req->status,
 616                                 req->status);
 617         } else {
 618                 /* ep_copy_to_user() won't report both; we hide some faults */
 619                 if (unlikely(0 != req->status))
 620                         DBG(epdata->dev, "%s fault %d len %d\n",
 621                                 ep->name, req->status, req->actual);
 622
 623                 priv->buf = req->buf;
 624                 priv->actual = req->actual;
 625                 schedule_work(&priv->work);
 626         }
 627         spin_unlock(&epdata->dev->lock);
 628
 629         usb_ep_free_request(ep, req);
 630         put_ep(epdata);
 631 }
 632
 633 static ssize_t
 634 ep_aio_rwtail(
 635         struct kiocb    *iocb,
 636         char            *buf,
 637         size_t          len,
 638         struct ep_data  *epdata,
 639         const struct iovec *iv,
 640         unsigned long   nr_segs
 641 )
 642 {
 643         struct kiocb_priv       *priv;
 644         struct usb_request      *req;
 645         ssize_t                 value;
 646
 647         priv = kmalloc(sizeof *priv, GFP_KERNEL);
 648         if (!priv) {
 649                 value = -ENOMEM;
 650 fail:
 651                 kfree(buf);
 652                 return value;
 653         }
 654         iocb->private = priv;
 655         priv->iocb = iocb;
 656         priv->iv = iv;
 657         priv->nr_segs = nr_segs;
 658         INIT_WORK(&priv->work, ep_user_copy_worker);
 659
 660         value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
 661         if (unlikely(value < 0)) {
 662                 kfree(priv);
 663                 goto fail;
 664         }
 665
 666         iocb->ki_cancel = ep_aio_cancel;
 667         get_ep(epdata);
 668         priv->epdata = epdata;
 669         priv->actual = 0;
 670         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 671
 672         /* each kiocb is coupled to one usb_request, but we can't
 673          * allocate or submit those if the host disconnected.
 674          */
 675         spin_lock_irq(&epdata->dev->lock);
 676         if (likely(epdata->ep)) {
 677                 req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 678                 if (likely(req)) {
 679                         priv->req = req;
 680                         req->buf = buf;
 681                         req->length = len;
 682                         req->complete = ep_aio_complete;
 683                         req->context = iocb;
 684                         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 685                         if (unlikely(0 != value))
 686                                 usb_ep_free_request(epdata->ep, req);
 687                 } else
 688                         value = -EAGAIN;
 689         } else
 690                 value = -ENODEV;
 691         spin_unlock_irq(&epdata->dev->lock);
 692
 693         mutex_unlock(&epdata->lock);
 694
 695         if (unlikely(value)) {
 696                 kfree(priv);
 697                 put_ep(epdata);
 698         } else
 699                 value = -EIOCBQUEUED;
 700         return value;
 701 }
 702
 703 static ssize_t
 704 ep_aio_read(struct kiocb *iocb, const struct iovec *iov,
 705                 unsigned long nr_segs, loff_t o)
 706 {
 707         struct ep_data          *epdata = iocb->ki_filp->private_data;
 708         char                    *buf;
 709
 710         if (unlikely(usb_endpoint_dir_in(&epdata->desc)))
 711                 return -EINVAL;
 712
 713         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 714         if (unlikely(!buf))
 715                 return -ENOMEM;
 716
 717         return ep_aio_rwtail(iocb, buf, iocb->ki_left, epdata, iov, nr_segs);
 718 }
 719
 720 static ssize_t
 721 ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
 722                 unsigned long nr_segs, loff_t o)
 723 {
 724         struct ep_data          *epdata = iocb->ki_filp->private_data;
 725         char                    *buf;
 726         size_t                  len = 0;
 727         int                     i = 0;
 728
 729         if (unlikely(!usb_endpoint_dir_in(&epdata->desc)))
 730                 return -EINVAL;
 731
 732         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 733         if (unlikely(!buf))
 734                 return -ENOMEM;
 735
 736         for (i=0; i < nr_segs; i++) {
 737                 if (unlikely(copy_from_user(&buf[len], iov[i].iov_base,
 738                                 iov[i].iov_len) != 0)) {
 739                         kfree(buf);
 740                         return -EFAULT;
 741                 }
 742                 len += iov[i].iov_len;
 743         }
 744         return ep_aio_rwtail(iocb, buf, len, epdata, NULL, 0);
 745 }
 746
 747 /*----------------------------------------------------------------------*/
 748
 749 /* used after endpoint configuration */
 750 static const struct file_operations ep_io_operations = {
 751         .owner =        THIS_MODULE,
 752         .llseek =       no_llseek,
 753
 754         .read =         ep_read,
 755         .write =        ep_write,
 756         .unlocked_ioctl = ep_ioctl,
 757         .release =      ep_release,
 758
 759         .aio_read =     ep_aio_read,
 760         .aio_write =    ep_aio_write,
 761 };
 762
 763 /* ENDPOINT INITIALIZATION
 764  *
 765  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 766  *     status = write (fd, descriptors, sizeof descriptors)
 767  *
 768  * That write establishes the endpoint configuration, configuring
 769  * the controller to process bulk, interrupt, or isochronous transfers
 770  * at the right maxpacket size, and so on.
 771  *
 772  * The descriptors are message type 1, identified by a host order u32
 773  * at the beginning of what's written.  Descriptor order is: full/low
 774  * speed descriptor, then optional high speed descriptor.
 775  */
 776 static ssize_t
 777 ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 778 {
 779         struct ep_data          *data = fd->private_data;
 780         struct usb_ep           *ep;
 781         u32                     tag;
 782         int                     value, length = len;
 783
 784         value = mutex_lock_interruptible(&data->lock);
 785         if (value < 0)
 786                 return value;
 787
 788         if (data->state != STATE_EP_READY) {
 789                 value = -EL2HLT;
 790                 goto fail;
 791         }
 792
 793         value = len;
 794         if (len < USB_DT_ENDPOINT_SIZE + 4)
 795                 goto fail0;
 796
 797         /* we might need to change message format someday */
 798         if (copy_from_user (&tag, buf, 4)) {
 799                 goto fail1;
 800         }
 801         if (tag != 1) {
 802                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 803                 goto fail0;
 804         }
 805         buf += 4;
 806         len -= 4;
 807
 808         /* NOTE:  audio endpoint extensions not accepted here;
 809          * just don't include the extra bytes.
 810          */
 811
 812         /* full/low speed descriptor, then high speed */
 813         if (copy_from_user (&data->desc, buf, USB_DT_ENDPOINT_SIZE)) {
 814                 goto fail1;
 815         }
 816         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 817                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 818                 goto fail0;
 819         if (len != USB_DT_ENDPOINT_SIZE) {
 820                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 821                         goto fail0;
 822                 if (copy_from_user (&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 823                                         USB_DT_ENDPOINT_SIZE)) {
 824                         goto fail1;
 825                 }
 826                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 827                                 || data->hs_desc.bDescriptorType
 828                                         != USB_DT_ENDPOINT) {
 829                         DBG(data->dev, "config %s, bad hs length or type\n",
 830                                         data->name);
 831                         goto fail0;
 832                 }
 833         }
 834
 835         spin_lock_irq (&data->dev->lock);
 836         if (data->dev->state == STATE_DEV_UNBOUND) {
 837                 value = -ENOENT;
 838                 goto gone;
 839         } else if ((ep = data->ep) == NULL) {
 840                 value = -ENODEV;
 841                 goto gone;
 842         }
 843         switch (data->dev->gadget->speed) {
 844         case USB_SPEED_LOW:
 845         case USB_SPEED_FULL:
 846                 ep->desc = &data->desc;
 847                 value = usb_ep_enable(ep);
 848                 if (value == 0)
 849                         data->state = STATE_EP_ENABLED;
 850                 break;
 851         case USB_SPEED_HIGH:
 852                 /* fails if caller didn't provide that descriptor... */
 853                 ep->desc = &data->hs_desc;
 854                 value = usb_ep_enable(ep);
 855                 if (value == 0)
 856                         data->state = STATE_EP_ENABLED;
 857                 break;
 858         default:
 859                 DBG(data->dev, "unconnected, %s init abandoned\n",
 860                                 data->name);
 861                 value = -EINVAL;
 862         }
 863         if (value == 0) {
 864                 fd->f_op = &ep_io_operations;
 865                 value = length;
 866         }
 867 gone:
 868         spin_unlock_irq (&data->dev->lock);
 869         if (value < 0) {
 870 fail:
 871                 data->desc.bDescriptorType = 0;
 872                 data->hs_desc.bDescriptorType = 0;
 873         }
 874         mutex_unlock(&data->lock);
 875         return value;
 876 fail0:
 877         value = -EINVAL;
 878         goto fail;
 879 fail1:
 880         value = -EFAULT;
 881         goto fail;
 882 }
 883
 884 static int
 885 ep_open (struct inode *inode, struct file *fd)
 886 {
 887         struct ep_data          *data = inode->i_private;
 888         int                     value = -EBUSY;
 889
 890         if (mutex_lock_interruptible(&data->lock) != 0)
 891                 return -EINTR;
 892         spin_lock_irq (&data->dev->lock);
 893         if (data->dev->state == STATE_DEV_UNBOUND)
 894                 value = -ENOENT;
 895         else if (data->state == STATE_EP_DISABLED) {
 896                 value = 0;
 897                 data->state = STATE_EP_READY;
 898                 get_ep (data);
 899                 fd->private_data = data;
 900                 VDEBUG (data->dev, "%s ready\n", data->name);
 901         } else
 902                 DBG (data->dev, "%s state %d\n",
 903                         data->name, data->state);
 904         spin_unlock_irq (&data->dev->lock);
 905         mutex_unlock(&data->lock);
 906         return value;
 907 }
 908
 909 /* used before endpoint configuration */
 910 static const struct file_operations ep_config_operations = {
 911         .llseek =       no_llseek,
 912
 913         .open =         ep_open,
 914         .write =        ep_config,
 915         .release =      ep_release,
 916 };
 917
 918 /*----------------------------------------------------------------------*/
 919
 920 /* EP0 IMPLEMENTATION can be partly in userspace.
 921  *
 922  * Drivers that use this facility receive various events, including
 923  * control requests the kernel doesn't handle.  Drivers that don't
 924  * use this facility may be too simple-minded for real applications.
 925  */
 926
 927 static inline void ep0_readable (struct dev_data *dev)
 928 {
 929         wake_up (&dev->wait);
 930         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 931 }
 932
 933 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 934 {
 935         struct dev_data         *dev = ep->driver_data;
 936
 937         if (req->buf != dev->rbuf) {
 938                 kfree(req->buf);
 939                 req->buf = dev->rbuf;
 940         }
 941         req->complete = epio_complete;
 942         dev->setup_out_ready = 0;
 943 }
 944
 945 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 946 {
 947         struct dev_data         *dev = ep->driver_data;
 948         unsigned long           flags;
 949         int                     free = 1;
 950
 951         /* for control OUT, data must still get to userspace */
 952         spin_lock_irqsave(&dev->lock, flags);
 953         if (!dev->setup_in) {
 954                 dev->setup_out_error = (req->status != 0);
 955                 if (!dev->setup_out_error)
 956                         free = 0;
 957                 dev->setup_out_ready = 1;
 958                 ep0_readable (dev);
 959         }
 960
 961         /* clean up as appropriate */
 962         if (free && req->buf != &dev->rbuf)
 963                 clean_req (ep, req);
 964         req->complete = epio_complete;
 965         spin_unlock_irqrestore(&dev->lock, flags);
 966 }
 967
 968 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 969 {
 970         struct dev_data *dev = ep->driver_data;
 971
 972         if (dev->setup_out_ready) {
 973                 DBG (dev, "ep0 request busy!\n");
 974                 return -EBUSY;
 975         }
 976         if (len > sizeof (dev->rbuf))
 977                 req->buf = kmalloc(len, GFP_ATOMIC);
 978         if (req->buf == NULL) {
 979                 req->buf = dev->rbuf;
 980                 return -ENOMEM;
 981         }
 982         req->complete = ep0_complete;
 983         req->length = len;
 984         req->zero = 0;
 985         return 0;
 986 }
 987
 988 static ssize_t
 989 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 990 {
 991         struct dev_data                 *dev = fd->private_data;
 992         ssize_t                         retval;
 993         enum ep0_state                  state;
 994
 995         spin_lock_irq (&dev->lock);
 996
 997         /* report fd mode change before acting on it */
 998         if (dev->setup_abort) {
 999                 dev->setup_abort = 0;
1000                 retval = -EIDRM;
1001                 goto done;
1002         }
1003
1004         /* control DATA stage */
1005         if ((state = dev->state) == STATE_DEV_SETUP) {
1006
1007                 if (dev->setup_in) {            /* stall IN */
1008                         VDEBUG(dev, "ep0in stall\n");
1009                         (void) usb_ep_set_halt (dev->gadget->ep0);
1010                         retval = -EL2HLT;
1011                         dev->state = STATE_DEV_CONNECTED;
1012
1013                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
1014                         struct usb_ep           *ep = dev->gadget->ep0;
1015                         struct usb_request      *req = dev->req;
1016
1017                         if ((retval = setup_req (ep, req, 0)) == 0)
1018                                 retval = usb_ep_queue (ep, req, GFP_ATOMIC);
1019                         dev->state = STATE_DEV_CONNECTED;
1020
1021                         /* assume that was SET_CONFIGURATION */
1022                         if (dev->current_config) {
1023                                 unsigned power;
1024
1025                                 if (gadget_is_dualspeed(dev->gadget)
1026                                                 && (dev->gadget->speed
1027                                                         == USB_SPEED_HIGH))
1028                                         power = dev->hs_config->bMaxPower;
1029                                 else
1030                                         power = dev->config->bMaxPower;
1031                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
1032                         }
1033
1034                 } else {                        /* collect OUT data */
1035                         if ((fd->f_flags & O_NONBLOCK) != 0
1036                                         && !dev->setup_out_ready) {
1037                                 retval = -EAGAIN;
1038                                 goto done;
1039                         }
1040                         spin_unlock_irq (&dev->lock);
1041                         retval = wait_event_interruptible (dev->wait,
1042                                         dev->setup_out_ready != 0);
1043
1044                         /* FIXME state could change from under us */
1045                         spin_lock_irq (&dev->lock);
1046                         if (retval)
1047                                 goto done;
1048
1049                         if (dev->state != STATE_DEV_SETUP) {
1050                                 retval = -ECANCELED;
1051                                 goto done;
1052                         }
1053                         dev->state = STATE_DEV_CONNECTED;
1054
1055                         if (dev->setup_out_error)
1056                                 retval = -EIO;
1057                         else {
1058                                 len = min (len, (size_t)dev->req->actual);
1059 // FIXME don't call this with the spinlock held ...
1060                                 if (copy_to_user (buf, dev->req->buf, len))
1061                                         retval = -EFAULT;
1062                                 else
1063                                         retval = len;
1064                                 clean_req (dev->gadget->ep0, dev->req);
1065                                 /* NOTE userspace can't yet choose to stall */
1066                         }
1067                 }
1068                 goto done;
1069         }
1070
1071         /* else normal: return event data */
1072         if (len < sizeof dev->event [0]) {
1073                 retval = -EINVAL;
1074                 goto done;
1075         }
1076         len -= len % sizeof (struct usb_gadgetfs_event);
1077         dev->usermode_setup = 1;
1078
1079 scan:
1080         /* return queued events right away */
1081         if (dev->ev_next != 0) {
1082                 unsigned                i, n;
1083
1084                 n = len / sizeof (struct usb_gadgetfs_event);
1085                 if (dev->ev_next < n)
1086                         n = dev->ev_next;
1087
1088                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1089                 for (i = 0; i < n; i++) {
1090                         if (dev->event [i].type == GADGETFS_SETUP) {
1091                                 dev->state = STATE_DEV_SETUP;
1092                                 n = i + 1;
1093                                 break;
1094                         }
1095                 }
1096                 spin_unlock_irq (&dev->lock);
1097                 len = n * sizeof (struct usb_gadgetfs_event);
1098                 if (copy_to_user (buf, &dev->event, len))
1099                         retval = -EFAULT;
1100                 else
1101                         retval = len;
1102                 if (len > 0) {
1103                         /* NOTE this doesn't guard against broken drivers;
1104                          * concurrent ep0 readers may lose events.
1105                          */
1106                         spin_lock_irq (&dev->lock);
1107                         if (dev->ev_next > n) {
1108                                 memmove(&dev->event[0], &dev->event[n],
1109                                         sizeof (struct usb_gadgetfs_event)
1110                                                 * (dev->ev_next - n));
1111                         }
1112                         dev->ev_next -= n;
1113                         spin_unlock_irq (&dev->lock);
1114                 }
1115                 return retval;
1116         }
1117         if (fd->f_flags & O_NONBLOCK) {
1118                 retval = -EAGAIN;
1119                 goto done;
1120         }
1121
1122         switch (state) {
1123         default:
1124                 DBG (dev, "fail %s, state %d\n", __func__, state);
1125                 retval = -ESRCH;
1126                 break;
1127         case STATE_DEV_UNCONNECTED:
1128         case STATE_DEV_CONNECTED:
1129                 spin_unlock_irq (&dev->lock);
1130                 DBG (dev, "%s wait\n", __func__);
1131
1132                 /* wait for events */
1133                 retval = wait_event_interruptible (dev->wait,
1134                                 dev->ev_next != 0);
1135                 if (retval < 0)
1136                         return retval;
1137                 spin_lock_irq (&dev->lock);
1138                 goto scan;
1139         }
1140
1141 done:
1142         spin_unlock_irq (&dev->lock);
1143         return retval;
1144 }
1145
1146 static struct usb_gadgetfs_event *
1147 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1148 {
1149         struct usb_gadgetfs_event       *event;
1150         unsigned                        i;
1151
1152         switch (type) {
1153         /* these events purge the queue */
1154         case GADGETFS_DISCONNECT:
1155                 if (dev->state == STATE_DEV_SETUP)
1156                         dev->setup_abort = 1;
1157                 // FALL THROUGH
1158         case GADGETFS_CONNECT:
1159                 dev->ev_next = 0;
1160                 break;
1161         case GADGETFS_SETUP:            /* previous request timed out */
1162         case GADGETFS_SUSPEND:          /* same effect */
1163                 /* these events can't be repeated */
1164                 for (i = 0; i != dev->ev_next; i++) {
1165                         if (dev->event [i].type != type)
1166                                 continue;
1167                         DBG(dev, "discard old event[%d] %d\n", i, type);
1168                         dev->ev_next--;
1169                         if (i == dev->ev_next)
1170                                 break;
1171                         /* indices start at zero, for simplicity */
1172                         memmove (&dev->event [i], &dev->event [i + 1],
1173                                 sizeof (struct usb_gadgetfs_event)
1174                                         * (dev->ev_next - i));
1175                 }
1176                 break;
1177         default:
1178                 BUG ();
1179         }
1180         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1181         event = &dev->event [dev->ev_next++];
1182         BUG_ON (dev->ev_next > N_EVENT);
1183         memset (event, 0, sizeof *event);
1184         event->type = type;
1185         return event;
1186 }
1187
1188 static ssize_t
1189 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1190 {
1191         struct dev_data         *dev = fd->private_data;
1192         ssize_t                 retval = -ESRCH;
1193
1194         spin_lock_irq (&dev->lock);
1195
1196         /* report fd mode change before acting on it */
1197         if (dev->setup_abort) {
1198                 dev->setup_abort = 0;
1199                 retval = -EIDRM;
1200
1201         /* data and/or status stage for control request */
1202         } else if (dev->state == STATE_DEV_SETUP) {
1203
1204                 /* IN DATA+STATUS caller makes len <= wLength */
1205                 if (dev->setup_in) {
1206                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1207                         if (retval == 0) {
1208                                 dev->state = STATE_DEV_CONNECTED;
1209                                 spin_unlock_irq (&dev->lock);
1210                                 if (copy_from_user (dev->req->buf, buf, len))
1211                                         retval = -EFAULT;
1212                                 else {
1213                                         if (len < dev->setup_wLength)
1214                                                 dev->req->zero = 1;
1215                                         retval = usb_ep_queue (
1216                                                 dev->gadget->ep0, dev->req,
1217                                                 GFP_KERNEL);
1218                                 }
1219                                 if (retval < 0) {
1220                                         spin_lock_irq (&dev->lock);
1221                                         clean_req (dev->gadget->ep0, dev->req);
1222                                         spin_unlock_irq (&dev->lock);
1223                                 } else
1224                                         retval = len;
1225
1226                                 return retval;
1227                         }
1228
1229                 /* can stall some OUT transfers */
1230                 } else if (dev->setup_can_stall) {
1231                         VDEBUG(dev, "ep0out stall\n");
1232                         (void) usb_ep_set_halt (dev->gadget->ep0);
1233                         retval = -EL2HLT;
1234                         dev->state = STATE_DEV_CONNECTED;
1235                 } else {
1236                         DBG(dev, "bogus ep0out stall!\n");
1237                 }
1238         } else
1239                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1240
1241         spin_unlock_irq (&dev->lock);
1242         return retval;
1243 }
1244
1245 static int
1246 ep0_fasync (int f, struct file *fd, int on)
1247 {
1248         struct dev_data         *dev = fd->private_data;
1249         // caller must F_SETOWN before signal delivery happens
1250         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1251         return fasync_helper (f, fd, on, &dev->fasync);
1252 }
1253
1254 static struct usb_gadget_driver gadgetfs_driver;
1255
1256 static int
1257 dev_release (struct inode *inode, struct file *fd)
1258 {
1259         struct dev_data         *dev = fd->private_data;
1260
1261         /* closing ep0 === shutdown all */
1262
1263         usb_gadget_unregister_driver (&gadgetfs_driver);
1264
1265         /* at this point "good" hardware has disconnected the
1266          * device from USB; the host won't see it any more.
1267          * alternatively, all host requests will time out.
1268          */
1269
1270         kfree (dev->buf);
1271         dev->buf = NULL;
1272         put_dev (dev);
1273
1274         /* other endpoints were all decoupled from this device */
1275         spin_lock_irq(&dev->lock);
1276         dev->state = STATE_DEV_DISABLED;
1277         spin_unlock_irq(&dev->lock);
1278         return 0;
1279 }
1280
1281 static unsigned int
1282 ep0_poll (struct file *fd, poll_table *wait)
1283 {
1284        struct dev_data         *dev = fd->private_data;
1285        int                     mask = 0;
1286
1287        poll_wait(fd, &dev->wait, wait);
1288
1289        spin_lock_irq (&dev->lock);
1290
1291        /* report fd mode change before acting on it */
1292        if (dev->setup_abort) {
1293                dev->setup_abort = 0;
1294                mask = POLLHUP;
1295                goto out;
1296        }
1297
1298        if (dev->state == STATE_DEV_SETUP) {
1299                if (dev->setup_in || dev->setup_can_stall)
1300                        mask = POLLOUT;
1301        } else {
1302                if (dev->ev_next != 0)
1303                        mask = POLLIN;
1304        }
1305 out:
1306        spin_unlock_irq(&dev->lock);
1307        return mask;
1308 }
1309
1310 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1311 {
1312         struct dev_data         *dev = fd->private_data;
1313         struct usb_gadget       *gadget = dev->gadget;
1314         long ret = -ENOTTY;
1315
1316         if (gadget->ops->ioctl)
1317                 ret = gadget->ops->ioctl (gadget, code, value);
1318
1319         return ret;
1320 }
1321
1322 /* used after device configuration */
1323 static const struct file_operations ep0_io_operations = {
1324         .owner =        THIS_MODULE,
1325         .llseek =       no_llseek,
1326
1327         .read =         ep0_read,
1328         .write =        ep0_write,
1329         .fasync =       ep0_fasync,
1330         .poll =         ep0_poll,
1331         .unlocked_ioctl =       dev_ioctl,
1332         .release =      dev_release,
1333 };
1334
1335 /*----------------------------------------------------------------------*/
1336
1337 /* The in-kernel gadget driver handles most ep0 issues, in particular
1338  * enumerating the single configuration (as provided from user space).
1339  *
1340  * Unrecognized ep0 requests may be handled in user space.
1341  */
1342
1343 static void make_qualifier (struct dev_data *dev)
1344 {
1345         struct usb_qualifier_descriptor         qual;
1346         struct usb_device_descriptor            *desc;
1347
1348         qual.bLength = sizeof qual;
1349         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1350         qual.bcdUSB = cpu_to_le16 (0x0200);
1351
1352         desc = dev->dev;
1353         qual.bDeviceClass = desc->bDeviceClass;
1354         qual.bDeviceSubClass = desc->bDeviceSubClass;
1355         qual.bDeviceProtocol = desc->bDeviceProtocol;
1356
1357         /* assumes ep0 uses the same value for both speeds ... */
1358         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1359
1360         qual.bNumConfigurations = 1;
1361         qual.bRESERVED = 0;
1362
1363         memcpy (dev->rbuf, &qual, sizeof qual);
1364 }
1365
1366 static int
1367 config_buf (struct dev_data *dev, u8 type, unsigned index)
1368 {
1369         int             len;
1370         int             hs = 0;
1371
1372         /* only one configuration */
1373         if (index > 0)
1374                 return -EINVAL;
1375
1376         if (gadget_is_dualspeed(dev->gadget)) {
1377                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1378                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1379                         hs = !hs;
1380         }
1381         if (hs) {
1382                 dev->req->buf = dev->hs_config;
1383                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1384         } else {
1385                 dev->req->buf = dev->config;
1386                 len = le16_to_cpu(dev->config->wTotalLength);
1387         }
1388         ((u8 *)dev->req->buf) [1] = type;
1389         return len;
1390 }
1391
1392 static int
1393 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1394 {
1395         struct dev_data                 *dev = get_gadget_data (gadget);
1396         struct usb_request              *req = dev->req;
1397         int                             value = -EOPNOTSUPP;
1398         struct usb_gadgetfs_event       *event;
1399         u16                             w_value = le16_to_cpu(ctrl->wValue);
1400         u16                             w_length = le16_to_cpu(ctrl->wLength);
1401
1402         spin_lock (&dev->lock);
1403         dev->setup_abort = 0;
1404         if (dev->state == STATE_DEV_UNCONNECTED) {
1405                 if (gadget_is_dualspeed(gadget)
1406                                 && gadget->speed == USB_SPEED_HIGH
1407                                 && dev->hs_config == NULL) {
1408                         spin_unlock(&dev->lock);
1409                         ERROR (dev, "no high speed config??\n");
1410                         return -EINVAL;
1411                 }
1412
1413                 dev->state = STATE_DEV_CONNECTED;
1414
1415                 INFO (dev, "connected\n");
1416                 event = next_event (dev, GADGETFS_CONNECT);
1417                 event->u.speed = gadget->speed;
1418                 ep0_readable (dev);
1419
1420         /* host may have given up waiting for response.  we can miss control
1421          * requests handled lower down (device/endpoint status and features);
1422          * then ep0_{read,write} will report the wrong status. controller
1423          * driver will have aborted pending i/o.
1424          */
1425         } else if (dev->state == STATE_DEV_SETUP)
1426                 dev->setup_abort = 1;
1427
1428         req->buf = dev->rbuf;
1429         req->context = NULL;
1430         value = -EOPNOTSUPP;
1431         switch (ctrl->bRequest) {
1432
1433         case USB_REQ_GET_DESCRIPTOR:
1434                 if (ctrl->bRequestType != USB_DIR_IN)
1435                         goto unrecognized;
1436                 switch (w_value >> 8) {
1437
1438                 case USB_DT_DEVICE:
1439                         value = min (w_length, (u16) sizeof *dev->dev);
1440                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1441                         req->buf = dev->dev;
1442                         break;
1443                 case USB_DT_DEVICE_QUALIFIER:
1444                         if (!dev->hs_config)
1445                                 break;
1446                         value = min (w_length, (u16)
1447                                 sizeof (struct usb_qualifier_descriptor));
1448                         make_qualifier (dev);
1449                         break;
1450                 case USB_DT_OTHER_SPEED_CONFIG:
1451                         // FALLTHROUGH
1452                 case USB_DT_CONFIG:
1453                         value = config_buf (dev,
1454                                         w_value >> 8,
1455                                         w_value & 0xff);
1456                         if (value >= 0)
1457                                 value = min (w_length, (u16) value);
1458                         break;
1459                 case USB_DT_STRING:
1460                         goto unrecognized;
1461
1462                 default:                // all others are errors
1463                         break;
1464                 }
1465                 break;
1466
1467         /* currently one config, two speeds */
1468         case USB_REQ_SET_CONFIGURATION:
1469                 if (ctrl->bRequestType != 0)
1470                         goto unrecognized;
1471                 if (0 == (u8) w_value) {
1472                         value = 0;
1473                         dev->current_config = 0;
1474                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1475                         // user mode expected to disable endpoints
1476                 } else {
1477                         u8      config, power;
1478
1479                         if (gadget_is_dualspeed(gadget)
1480                                         && gadget->speed == USB_SPEED_HIGH) {
1481                                 config = dev->hs_config->bConfigurationValue;
1482                                 power = dev->hs_config->bMaxPower;
1483                         } else {
1484                                 config = dev->config->bConfigurationValue;
1485                                 power = dev->config->bMaxPower;
1486                         }
1487
1488                         if (config == (u8) w_value) {
1489                                 value = 0;
1490                                 dev->current_config = config;
1491                                 usb_gadget_vbus_draw(gadget, 2 * power);
1492                         }
1493                 }
1494
1495                 /* report SET_CONFIGURATION like any other control request,
1496                  * except that usermode may not stall this.  the next
1497                  * request mustn't be allowed start until this finishes:
1498                  * endpoints and threads set up, etc.
1499                  *
1500                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1501                  * has bad/racey automagic that prevents synchronizing here.
1502                  * even kernel mode drivers often miss them.
1503                  */
1504                 if (value == 0) {
1505                         INFO (dev, "configuration #%d\n", dev->current_config);
1506                         if (dev->usermode_setup) {
1507                                 dev->setup_can_stall = 0;
1508                                 goto delegate;
1509                         }
1510                 }
1511                 break;
1512
1513 #ifndef CONFIG_USB_GADGET_PXA25X
1514         /* PXA automagically handles this request too */
1515         case USB_REQ_GET_CONFIGURATION:
1516                 if (ctrl->bRequestType != 0x80)
1517                         goto unrecognized;
1518                 *(u8 *)req->buf = dev->current_config;
1519                 value = min (w_length, (u16) 1);
1520                 break;
1521 #endif
1522
1523         default:
1524 unrecognized:
1525                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1526                         dev->usermode_setup ? "delegate" : "fail",
1527                         ctrl->bRequestType, ctrl->bRequest,
1528                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1529
1530                 /* if there's an ep0 reader, don't stall */
1531                 if (dev->usermode_setup) {
1532                         dev->setup_can_stall = 1;
1533 delegate:
1534                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1535                                                 ? 1 : 0;
1536                         dev->setup_wLength = w_length;
1537                         dev->setup_out_ready = 0;
1538                         dev->setup_out_error = 0;
1539                         value = 0;
1540
1541                         /* read DATA stage for OUT right away */
1542                         if (unlikely (!dev->setup_in && w_length)) {
1543                                 value = setup_req (gadget->ep0, dev->req,
1544                                                         w_length);
1545                                 if (value < 0)
1546                                         break;
1547                                 value = usb_ep_queue (gadget->ep0, dev->req,
1548                                                         GFP_ATOMIC);
1549                                 if (value < 0) {
1550                                         clean_req (gadget->ep0, dev->req);
1551                                         break;
1552                                 }
1553
1554                                 /* we can't currently stall these */
1555                                 dev->setup_can_stall = 0;
1556                         }
1557
1558                         /* state changes when reader collects event */
1559                         event = next_event (dev, GADGETFS_SETUP);
1560                         event->u.setup = *ctrl;
1561                         ep0_readable (dev);
1562                         spin_unlock (&dev->lock);
1563                         return 0;
1564                 }
1565         }
1566
1567         /* proceed with data transfer and status phases? */
1568         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1569                 req->length = value;
1570                 req->zero = value < w_length;
1571                 value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
1572                 if (value < 0) {
1573                         DBG (dev, "ep_queue --> %d\n", value);
1574                         req->status = 0;
1575                 }
1576         }
1577
1578         /* device stalls when value < 0 */
1579         spin_unlock (&dev->lock);
1580         return value;
1581 }
1582
1583 static void destroy_ep_files (struct dev_data *dev)
1584 {
1585         DBG (dev, "%s %d\n", __func__, dev->state);
1586
1587         /* dev->state must prevent interference */
1588         spin_lock_irq (&dev->lock);
1589         while (!list_empty(&dev->epfiles)) {
1590                 struct ep_data  *ep;
1591                 struct inode    *parent;
1592                 struct dentry   *dentry;
1593
1594                 /* break link to FS */
1595                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1596                 list_del_init (&ep->epfiles);
1597                 dentry = ep->dentry;
1598                 ep->dentry = NULL;
1599                 parent = dentry->d_parent->d_inode;
1600
1601                 /* break link to controller */
1602                 if (ep->state == STATE_EP_ENABLED)
1603                         (void) usb_ep_disable (ep->ep);
1604                 ep->state = STATE_EP_UNBOUND;
1605                 usb_ep_free_request (ep->ep, ep->req);
1606                 ep->ep = NULL;
1607                 wake_up (&ep->wait);
1608                 put_ep (ep);
1609
1610                 spin_unlock_irq (&dev->lock);
1611
1612                 /* break link to dcache */
1613                 mutex_lock (&parent->i_mutex);
1614                 d_delete (dentry);
1615                 dput (dentry);
1616                 mutex_unlock (&parent->i_mutex);
1617
1618                 spin_lock_irq (&dev->lock);
1619         }
1620         spin_unlock_irq (&dev->lock);
1621 }
1622
1623
1624 static struct inode *
1625 gadgetfs_create_file (struct super_block *sb, char const *name,
1626                 void *data, const struct file_operations *fops,
1627                 struct dentry **dentry_p);
1628
1629 static int activate_ep_files (struct dev_data *dev)
1630 {
1631         struct usb_ep   *ep;
1632         struct ep_data  *data;
1633
1634         gadget_for_each_ep (ep, dev->gadget) {
1635
1636                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1637                 if (!data)
1638                         goto enomem0;
1639                 data->state = STATE_EP_DISABLED;
1640                 mutex_init(&data->lock);
1641                 init_waitqueue_head (&data->wait);
1642
1643                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1644                 atomic_set (&data->count, 1);
1645                 data->dev = dev;
1646                 get_dev (dev);
1647
1648                 data->ep = ep;
1649                 ep->driver_data = data;
1650
1651                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1652                 if (!data->req)
1653                         goto enomem1;
1654
1655                 data->inode = gadgetfs_create_file (dev->sb, data->name,
1656                                 data, &ep_config_operations,
1657                                 &data->dentry);
1658                 if (!data->inode)
1659                         goto enomem2;
1660                 list_add_tail (&data->epfiles, &dev->epfiles);
1661         }
1662         return 0;
1663
1664 enomem2:
1665         usb_ep_free_request (ep, data->req);
1666 enomem1:
1667         put_dev (dev);
1668         kfree (data);
1669 enomem0:
1670         DBG (dev, "%s enomem\n", __func__);
1671         destroy_ep_files (dev);
1672         return -ENOMEM;
1673 }
1674
1675 static void
1676 gadgetfs_unbind (struct usb_gadget *gadget)
1677 {
1678         struct dev_data         *dev = get_gadget_data (gadget);
1679
1680         DBG (dev, "%s\n", __func__);
1681
1682         spin_lock_irq (&dev->lock);
1683         dev->state = STATE_DEV_UNBOUND;
1684         spin_unlock_irq (&dev->lock);
1685
1686         destroy_ep_files (dev);
1687         gadget->ep0->driver_data = NULL;
1688         set_gadget_data (gadget, NULL);
1689
1690         /* we've already been disconnected ... no i/o is active */
1691         if (dev->req)
1692                 usb_ep_free_request (gadget->ep0, dev->req);
1693         DBG (dev, "%s done\n", __func__);
1694         put_dev (dev);
1695 }
1696
1697 static struct dev_data          *the_device;
1698
1699 static int gadgetfs_bind(struct usb_gadget *gadget,
1700                 struct usb_gadget_driver *driver)
1701 {
1702         struct dev_data         *dev = the_device;
1703
1704         if (!dev)
1705                 return -ESRCH;
1706         if (0 != strcmp (CHIP, gadget->name)) {
1707                 pr_err("%s expected %s controller not %s\n",
1708                         shortname, CHIP, gadget->name);
1709                 return -ENODEV;
1710         }
1711
1712         set_gadget_data (gadget, dev);
1713         dev->gadget = gadget;
1714         gadget->ep0->driver_data = dev;
1715
1716         /* preallocate control response and buffer */
1717         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1718         if (!dev->req)
1719                 goto enomem;
1720         dev->req->context = NULL;
1721         dev->req->complete = epio_complete;
1722
1723         if (activate_ep_files (dev) < 0)
1724                 goto enomem;
1725
1726         INFO (dev, "bound to %s driver\n", gadget->name);
1727         spin_lock_irq(&dev->lock);
1728         dev->state = STATE_DEV_UNCONNECTED;
1729         spin_unlock_irq(&dev->lock);
1730         get_dev (dev);
1731         return 0;
1732
1733 enomem:
1734         gadgetfs_unbind (gadget);
1735         return -ENOMEM;
1736 }
1737
1738 static void
1739 gadgetfs_disconnect (struct usb_gadget *gadget)
1740 {
1741         struct dev_data         *dev = get_gadget_data (gadget);
1742         unsigned long           flags;
1743
1744         spin_lock_irqsave (&dev->lock, flags);
1745         if (dev->state == STATE_DEV_UNCONNECTED)
1746                 goto exit;
1747         dev->state = STATE_DEV_UNCONNECTED;
1748
1749         INFO (dev, "disconnected\n");
1750         next_event (dev, GADGETFS_DISCONNECT);
1751         ep0_readable (dev);
1752 exit:
1753         spin_unlock_irqrestore (&dev->lock, flags);
1754 }
1755
1756 static void
1757 gadgetfs_suspend (struct usb_gadget *gadget)
1758 {
1759         struct dev_data         *dev = get_gadget_data (gadget);
1760
1761         INFO (dev, "suspended from state %d\n", dev->state);
1762         spin_lock (&dev->lock);
1763         switch (dev->state) {
1764         case STATE_DEV_SETUP:           // VERY odd... host died??
1765         case STATE_DEV_CONNECTED:
1766         case STATE_DEV_UNCONNECTED:
1767                 next_event (dev, GADGETFS_SUSPEND);
1768                 ep0_readable (dev);
1769                 /* FALLTHROUGH */
1770         default:
1771                 break;
1772         }
1773         spin_unlock (&dev->lock);
1774 }
1775
1776 static struct usb_gadget_driver gadgetfs_driver = {
1777         .function       = (char *) driver_desc,
1778         .bind           = gadgetfs_bind,
1779         .unbind         = gadgetfs_unbind,
1780         .setup          = gadgetfs_setup,
1781         .disconnect     = gadgetfs_disconnect,
1782         .suspend        = gadgetfs_suspend,
1783
1784         .driver = {
1785                 .name           = (char *) shortname,
1786         },
1787 };
1788
1789 /*----------------------------------------------------------------------*/
1790
1791 static void gadgetfs_nop(struct usb_gadget *arg) { }
1792
1793 static int gadgetfs_probe(struct usb_gadget *gadget,
1794                 struct usb_gadget_driver *driver)
1795 {
1796         CHIP = gadget->name;
1797         return -EISNAM;
1798 }
1799
1800 static struct usb_gadget_driver probe_driver = {
1801         .max_speed      = USB_SPEED_HIGH,
1802         .bind           = gadgetfs_probe,
1803         .unbind         = gadgetfs_nop,
1804         .setup          = (void *)gadgetfs_nop,
1805         .disconnect     = gadgetfs_nop,
1806         .driver = {
1807                 .name           = "nop",
1808         },
1809 };
1810
1811
1812 /* DEVICE INITIALIZATION
1813  *
1814  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1815  *     status = write (fd, descriptors, sizeof descriptors)
1816  *
1817  * That write establishes the device configuration, so the kernel can
1818  * bind to the controller ... guaranteeing it can handle enumeration
1819  * at all necessary speeds.  Descriptor order is:
1820  *
1821  * . message tag (u32, host order) ... for now, must be zero; it
1822  *      would change to support features like multi-config devices
1823  * . full/low speed config ... all wTotalLength bytes (with interface,
1824  *      class, altsetting, endpoint, and other descriptors)
1825  * . high speed config ... all descriptors, for high speed operation;
1826  *      this one's optional except for high-speed hardware
1827  * . device descriptor
1828  *
1829  * Endpoints are not yet enabled. Drivers must wait until device
1830  * configuration and interface altsetting changes create
1831  * the need to configure (or unconfigure) them.
1832  *
1833  * After initialization, the device stays active for as long as that
1834  * $CHIP file is open.  Events must then be read from that descriptor,
1835  * such as configuration notifications.
1836  */
1837
1838 static int is_valid_config (struct usb_config_descriptor *config)
1839 {
1840         return config->bDescriptorType == USB_DT_CONFIG
1841                 && config->bLength == USB_DT_CONFIG_SIZE
1842                 && config->bConfigurationValue != 0
1843                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1844                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1845         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1846         /* FIXME check lengths: walk to end */
1847 }
1848
1849 static ssize_t
1850 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1851 {
1852         struct dev_data         *dev = fd->private_data;
1853         ssize_t                 value = len, length = len;
1854         unsigned                total;
1855         u32                     tag;
1856         char                    *kbuf;
1857
1858         if (len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4))
1859                 return -EINVAL;
1860
1861         /* we might need to change message format someday */
1862         if (copy_from_user (&tag, buf, 4))
1863                 return -EFAULT;
1864         if (tag != 0)
1865                 return -EINVAL;
1866         buf += 4;
1867         length -= 4;
1868
1869         kbuf = memdup_user(buf, length);
1870         if (IS_ERR(kbuf))
1871                 return PTR_ERR(kbuf);
1872
1873         spin_lock_irq (&dev->lock);
1874         value = -EINVAL;
1875         if (dev->buf)
1876                 goto fail;
1877         dev->buf = kbuf;
1878
1879         /* full or low speed config */
1880         dev->config = (void *) kbuf;
1881         total = le16_to_cpu(dev->config->wTotalLength);
1882         if (!is_valid_config (dev->config) || total >= length)
1883                 goto fail;
1884         kbuf += total;
1885         length -= total;
1886
1887         /* optional high speed config */
1888         if (kbuf [1] == USB_DT_CONFIG) {
1889                 dev->hs_config = (void *) kbuf;
1890                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1891                 if (!is_valid_config (dev->hs_config) || total >= length)
1892                         goto fail;
1893                 kbuf += total;
1894                 length -= total;
1895         }
1896
1897         /* could support multiple configs, using another encoding! */
1898
1899         /* device descriptor (tweaked for paranoia) */
1900         if (length != USB_DT_DEVICE_SIZE)
1901                 goto fail;
1902         dev->dev = (void *)kbuf;
1903         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1904                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1905                         || dev->dev->bNumConfigurations != 1)
1906                 goto fail;
1907         dev->dev->bNumConfigurations = 1;
1908         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1909
1910         /* triggers gadgetfs_bind(); then we can enumerate. */
1911         spin_unlock_irq (&dev->lock);
1912         if (dev->hs_config)
1913                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1914         else
1915                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1916
1917         value = usb_gadget_probe_driver(&gadgetfs_driver);
1918         if (value != 0) {
1919                 kfree (dev->buf);
1920                 dev->buf = NULL;
1921         } else {
1922                 /* at this point "good" hardware has for the first time
1923                  * let the USB the host see us.  alternatively, if users
1924                  * unplug/replug that will clear all the error state.
1925                  *
1926                  * note:  everything running before here was guaranteed
1927                  * to choke driver model style diagnostics.  from here
1928                  * on, they can work ... except in cleanup paths that
1929                  * kick in after the ep0 descriptor is closed.
1930                  */
1931                 fd->f_op = &ep0_io_operations;
1932                 value = len;
1933         }
1934         return value;
1935
1936 fail:
1937         spin_unlock_irq (&dev->lock);
1938         pr_debug ("%s: %s fail %Zd, %p\n", shortname, __func__, value, dev);
1939         kfree (dev->buf);
1940         dev->buf = NULL;
1941         return value;
1942 }
1943
1944 static int
1945 dev_open (struct inode *inode, struct file *fd)
1946 {
1947         struct dev_data         *dev = inode->i_private;
1948         int                     value = -EBUSY;
1949
1950         spin_lock_irq(&dev->lock);
1951         if (dev->state == STATE_DEV_DISABLED) {
1952                 dev->ev_next = 0;
1953                 dev->state = STATE_DEV_OPENED;
1954                 fd->private_data = dev;
1955                 get_dev (dev);
1956                 value = 0;
1957         }
1958         spin_unlock_irq(&dev->lock);
1959         return value;
1960 }
1961
1962 static const struct file_operations dev_init_operations = {
1963         .llseek =       no_llseek,
1964
1965         .open =         dev_open,
1966         .write =        dev_config,
1967         .fasync =       ep0_fasync,
1968         .unlocked_ioctl = dev_ioctl,
1969         .release =      dev_release,
1970 };
1971
1972 /*----------------------------------------------------------------------*/
1973
1974 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1975  *
1976  * Mounting the filesystem creates a controller file, used first for
1977  * device configuration then later for event monitoring.
1978  */
1979
1980
1981 /* FIXME PAM etc could set this security policy without mount options
1982  * if epfiles inherited ownership and permissons from ep0 ...
1983  */
1984
1985 static unsigned default_uid;
1986 static unsigned default_gid;
1987 static unsigned default_perm = S_IRUSR | S_IWUSR;
1988
1989 module_param (default_uid, uint, 0644);
1990 module_param (default_gid, uint, 0644);
1991 module_param (default_perm, uint, 0644);
1992
1993
1994 static struct inode *
1995 gadgetfs_make_inode (struct super_block *sb,
1996                 void *data, const struct file_operations *fops,
1997                 int mode)
1998 {
1999         struct inode *inode = new_inode (sb);
2000
2001         if (inode) {
2002                 inode->i_ino = get_next_ino();
2003                 inode->i_mode = mode;
2004                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
2005                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
2006                 inode->i_atime = inode->i_mtime = inode->i_ctime
2007                                 = CURRENT_TIME;
2008                 inode->i_private = data;
2009                 inode->i_fop = fops;
2010         }
2011         return inode;
2012 }
2013
2014 /* creates in fs root directory, so non-renamable and non-linkable.
2015  * so inode and dentry are paired, until device reconfig.
2016  */
2017 static struct inode *
2018 gadgetfs_create_file (struct super_block *sb, char const *name,
2019                 void *data, const struct file_operations *fops,
2020                 struct dentry **dentry_p)
2021 {
2022         struct dentry   *dentry;
2023         struct inode    *inode;
2024
2025         dentry = d_alloc_name(sb->s_root, name);
2026         if (!dentry)
2027                 return NULL;
2028
2029         inode = gadgetfs_make_inode (sb, data, fops,
2030                         S_IFREG | (default_perm & S_IRWXUGO));
2031         if (!inode) {
2032                 dput(dentry);
2033                 return NULL;
2034         }
2035         d_add (dentry, inode);
2036         *dentry_p = dentry;
2037         return inode;
2038 }
2039
2040 static const struct super_operations gadget_fs_operations = {
2041         .statfs =       simple_statfs,
2042         .drop_inode =   generic_delete_inode,
2043 };
2044
2045 static int
2046 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
2047 {
2048         struct inode    *inode;
2049         struct dev_data *dev;
2050
2051         if (the_device)
2052                 return -ESRCH;
2053
2054         /* fake probe to determine $CHIP */
2055         usb_gadget_probe_driver(&probe_driver);
2056         if (!CHIP)
2057                 return -ENODEV;
2058
2059         /* superblock */
2060         sb->s_blocksize = PAGE_CACHE_SIZE;
2061         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2062         sb->s_magic = GADGETFS_MAGIC;
2063         sb->s_op = &gadget_fs_operations;
2064         sb->s_time_gran = 1;
2065
2066         /* root inode */
2067         inode = gadgetfs_make_inode (sb,
2068                         NULL, &simple_dir_operations,
2069                         S_IFDIR | S_IRUGO | S_IXUGO);
2070         if (!inode)
2071                 goto Enomem;
2072         inode->i_op = &simple_dir_inode_operations;
2073         if (!(sb->s_root = d_make_root (inode)))
2074                 goto Enomem;
2075
2076         /* the ep0 file is named after the controller we expect;
2077          * user mode code can use it for sanity checks, like we do.
2078          */
2079         dev = dev_new ();
2080         if (!dev)
2081                 goto Enomem;
2082
2083         dev->sb = sb;
2084         if (!gadgetfs_create_file (sb, CHIP,
2085                                 dev, &dev_init_operations,
2086                                 &dev->dentry)) {
2087                 put_dev(dev);
2088                 goto Enomem;
2089         }
2090
2091         /* other endpoint files are available after hardware setup,
2092          * from binding to a controller.
2093          */
2094         the_device = dev;
2095         return 0;
2096
2097 Enomem:
2098         return -ENOMEM;
2099 }
2100
2101 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2102 static struct dentry *
2103 gadgetfs_mount (struct file_system_type *t, int flags,
2104                 const char *path, void *opts)
2105 {
2106         return mount_single (t, flags, opts, gadgetfs_fill_super);
2107 }
2108
2109 static void
2110 gadgetfs_kill_sb (struct super_block *sb)
2111 {
2112         kill_litter_super (sb);
2113         if (the_device) {
2114                 put_dev (the_device);
2115                 the_device = NULL;
2116         }
2117 }
2118
2119 /*----------------------------------------------------------------------*/
2120
2121 static struct file_system_type gadgetfs_type = {
2122         .owner          = THIS_MODULE,
2123         .name           = shortname,
2124         .mount          = gadgetfs_mount,
2125         .kill_sb        = gadgetfs_kill_sb,
2126 };
2127 MODULE_ALIAS_FS("gadgetfs");
2128
2129 /*----------------------------------------------------------------------*/
2130
2131 static int __init init (void)
2132 {
2133         int status;
2134
2135         status = register_filesystem (&gadgetfs_type);
2136         if (status == 0)
2137                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2138                         shortname, driver_desc);
2139         return status;
2140 }
2141 module_init (init);
2142
2143 static void __exit cleanup (void)
2144 {
2145         pr_debug ("unregister %s\n", shortname);
2146         unregister_filesystem (&gadgetfs_type);
2147 }
2148 module_exit (cleanup);
2149