drivers/usb/gadget/inode.c

   1 /*
   2  * inode.c -- user mode filesystem api for usb gadget controllers
   3  *
   4  * Copyright (C) 2003-2004 David Brownell
   5  * Copyright (C) 2003 Agilent Technologies
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13
  14 /* #define VERBOSE_DEBUG */
  15
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/fs.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/uts.h>
  21 #include <linux/wait.h>
  22 #include <linux/compiler.h>
  23 #include <asm/uaccess.h>
  24 #include <linux/sched.h>
  25 #include <linux/slab.h>
  26 #include <linux/poll.h>
  27
  28 #include <linux/device.h>
  29 #include <linux/moduleparam.h>
  30
  31 #include <linux/usb/gadgetfs.h>
  32 #include <linux/usb/gadget.h>
  33
  34
  35 /*
  36  * The gadgetfs API maps each endpoint to a file descriptor so that you
  37  * can use standard synchronous read/write calls for I/O.  There's some
  38  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  39  * drivers show how this works in practice.  You can also use AIO to
  40  * eliminate I/O gaps between requests, to help when streaming data.
  41  *
  42  * Key parts that must be USB-specific are protocols defining how the
  43  * read/write operations relate to the hardware state machines.  There
  44  * are two types of files.  One type is for the device, implementing ep0.
  45  * The other type is for each IN or OUT endpoint.  In both cases, the
  46  * user mode driver must configure the hardware before using it.
  47  *
  48  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  49  *   (by writing configuration and device descriptors).  Afterwards it
  50  *   may serve as a source of device events, used to handle all control
  51  *   requests other than basic enumeration.
  52  *
  53  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  54  *   called when each /dev/gadget/ep* file is configured (by writing
  55  *   endpoint descriptors).  Afterwards these files are used to write()
  56  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  57  *   direction" request is issued (like reading an IN endpoint).
  58  *
  59  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  60  * not possible on all hardware.  For example, precise fault handling with
  61  * respect to data left in endpoint fifos after aborted operations; or
  62  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  63  */
  64
  65 #define DRIVER_DESC     "USB Gadget filesystem"
  66 #define DRIVER_VERSION  "24 Aug 2004"
  67
  68 static const char driver_desc [] = DRIVER_DESC;
  69 static const char shortname [] = "gadgetfs";
  70
  71 MODULE_DESCRIPTION (DRIVER_DESC);
  72 MODULE_AUTHOR ("David Brownell");
  73 MODULE_LICENSE ("GPL");
  74
  75
  76 /*----------------------------------------------------------------------*/
  77
  78 #define GADGETFS_MAGIC          0xaee71ee7
  79 #define DMA_ADDR_INVALID        (~(dma_addr_t)0)
  80
  81 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  82 enum ep0_state {
  83         /* DISBLED is the initial state.
  84          */
  85         STATE_DEV_DISABLED = 0,
  86
  87         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  88          * ep0/device i/o modes and binding to the controller.  Driver
  89          * must always write descriptors to initialize the device, then
  90          * the device becomes UNCONNECTED until enumeration.
  91          */
  92         STATE_DEV_OPENED,
  93
  94         /* From then on, ep0 fd is in either of two basic modes:
  95          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
  96          * - SETUP: read/write will transfer control data and succeed;
  97          *   or if "wrong direction", performs protocol stall
  98          */
  99         STATE_DEV_UNCONNECTED,
 100         STATE_DEV_CONNECTED,
 101         STATE_DEV_SETUP,
 102
 103         /* UNBOUND means the driver closed ep0, so the device won't be
 104          * accessible again (DEV_DISABLED) until all fds are closed.
 105          */
 106         STATE_DEV_UNBOUND,
 107 };
 108
 109 /* enough for the whole queue: most events invalidate others */
 110 #define N_EVENT                 5
 111
 112 struct dev_data {
 113         spinlock_t                      lock;
 114         atomic_t                        count;
 115         enum ep0_state                  state;          /* P: lock */
 116         struct usb_gadgetfs_event       event [N_EVENT];
 117         unsigned                        ev_next;
 118         struct fasync_struct            *fasync;
 119         u8                              current_config;
 120
 121         /* drivers reading ep0 MUST handle control requests (SETUP)
 122          * reported that way; else the host will time out.
 123          */
 124         unsigned                        usermode_setup : 1,
 125                                         setup_in : 1,
 126                                         setup_can_stall : 1,
 127                                         setup_out_ready : 1,
 128                                         setup_out_error : 1,
 129                                         setup_abort : 1;
 130         unsigned                        setup_wLength;
 131
 132         /* the rest is basically write-once */
 133         struct usb_config_descriptor    *config, *hs_config;
 134         struct usb_device_descriptor    *dev;
 135         struct usb_request              *req;
 136         struct usb_gadget               *gadget;
 137         struct list_head                epfiles;
 138         void                            *buf;
 139         wait_queue_head_t               wait;
 140         struct super_block              *sb;
 141         struct dentry                   *dentry;
 142
 143         /* except this scratch i/o buffer for ep0 */
 144         u8                              rbuf [256];
 145 };
 146
 147 static inline void get_dev (struct dev_data *data)
 148 {
 149         atomic_inc (&data->count);
 150 }
 151
 152 static void put_dev (struct dev_data *data)
 153 {
 154         if (likely (!atomic_dec_and_test (&data->count)))
 155                 return;
 156         /* needs no more cleanup */
 157         BUG_ON (waitqueue_active (&data->wait));
 158         kfree (data);
 159 }
 160
 161 static struct dev_data *dev_new (void)
 162 {
 163         struct dev_data         *dev;
 164
 165         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 166         if (!dev)
 167                 return NULL;
 168         dev->state = STATE_DEV_DISABLED;
 169         atomic_set (&dev->count, 1);
 170         spin_lock_init (&dev->lock);
 171         INIT_LIST_HEAD (&dev->epfiles);
 172         init_waitqueue_head (&dev->wait);
 173         return dev;
 174 }
 175
 176 /*----------------------------------------------------------------------*/
 177
 178 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 179 enum ep_state {
 180         STATE_EP_DISABLED = 0,
 181         STATE_EP_READY,
 182         STATE_EP_ENABLED,
 183         STATE_EP_UNBOUND,
 184 };
 185
 186 struct ep_data {
 187         struct mutex                    lock;
 188         enum ep_state                   state;
 189         atomic_t                        count;
 190         struct dev_data                 *dev;
 191         /* must hold dev->lock before accessing ep or req */
 192         struct usb_ep                   *ep;
 193         struct usb_request              *req;
 194         ssize_t                         status;
 195         char                            name [16];
 196         struct usb_endpoint_descriptor  desc, hs_desc;
 197         struct list_head                epfiles;
 198         wait_queue_head_t               wait;
 199         struct dentry                   *dentry;
 200         struct inode                    *inode;
 201 };
 202
 203 static inline void get_ep (struct ep_data *data)
 204 {
 205         atomic_inc (&data->count);
 206 }
 207
 208 static void put_ep (struct ep_data *data)
 209 {
 210         if (likely (!atomic_dec_and_test (&data->count)))
 211                 return;
 212         put_dev (data->dev);
 213         /* needs no more cleanup */
 214         BUG_ON (!list_empty (&data->epfiles));
 215         BUG_ON (waitqueue_active (&data->wait));
 216         kfree (data);
 217 }
 218
 219 /*----------------------------------------------------------------------*/
 220
 221 /* most "how to use the hardware" policy choices are in userspace:
 222  * mapping endpoint roles (which the driver needs) to the capabilities
 223  * which the usb controller has.  most of those capabilities are exposed
 224  * implicitly, starting with the driver name and then endpoint names.
 225  */
 226
 227 static const char *CHIP;
 228
 229 /*----------------------------------------------------------------------*/
 230
 231 /* NOTE:  don't use dev_printk calls before binding to the gadget
 232  * at the end of ep0 configuration, or after unbind.
 233  */
 234
 235 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 236 #define xprintk(d,level,fmt,args...) \
 237         printk(level "%s: " fmt , shortname , ## args)
 238
 239 #ifdef DEBUG
 240 #define DBG(dev,fmt,args...) \
 241         xprintk(dev , KERN_DEBUG , fmt , ## args)
 242 #else
 243 #define DBG(dev,fmt,args...) \
 244         do { } while (0)
 245 #endif /* DEBUG */
 246
 247 #ifdef VERBOSE_DEBUG
 248 #define VDEBUG  DBG
 249 #else
 250 #define VDEBUG(dev,fmt,args...) \
 251         do { } while (0)
 252 #endif /* DEBUG */
 253
 254 #define ERROR(dev,fmt,args...) \
 255         xprintk(dev , KERN_ERR , fmt , ## args)
 256 #define INFO(dev,fmt,args...) \
 257         xprintk(dev , KERN_INFO , fmt , ## args)
 258
 259
 260 /*----------------------------------------------------------------------*/
 261
 262 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 263  *
 264  * After opening, configure non-control endpoints.  Then use normal
 265  * stream read() and write() requests; and maybe ioctl() to get more
 266  * precise FIFO status when recovering from cancellation.
 267  */
 268
 269 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 270 {
 271         struct ep_data  *epdata = ep->driver_data;
 272
 273         if (!req->context)
 274                 return;
 275         if (req->status)
 276                 epdata->status = req->status;
 277         else
 278                 epdata->status = req->actual;
 279         complete ((struct completion *)req->context);
 280 }
 281
 282 /* tasklock endpoint, returning when it's connected.
 283  * still need dev->lock to use epdata->ep.
 284  */
 285 static int
 286 get_ready_ep (unsigned f_flags, struct ep_data *epdata)
 287 {
 288         int     val;
 289
 290         if (f_flags & O_NONBLOCK) {
 291                 if (!mutex_trylock(&epdata->lock))
 292                         goto nonblock;
 293                 if (epdata->state != STATE_EP_ENABLED) {
 294                         mutex_unlock(&epdata->lock);
 295 nonblock:
 296                         val = -EAGAIN;
 297                 } else
 298                         val = 0;
 299                 return val;
 300         }
 301
 302         val = mutex_lock_interruptible(&epdata->lock);
 303         if (val < 0)
 304                 return val;
 305
 306         switch (epdata->state) {
 307         case STATE_EP_ENABLED:
 308                 break;
 309         // case STATE_EP_DISABLED:              /* "can't happen" */
 310         // case STATE_EP_READY:                 /* "can't happen" */
 311         default:                                /* error! */
 312                 pr_debug ("%s: ep %p not available, state %d\n",
 313                                 shortname, epdata, epdata->state);
 314                 // FALLTHROUGH
 315         case STATE_EP_UNBOUND:                  /* clean disconnect */
 316                 val = -ENODEV;
 317                 mutex_unlock(&epdata->lock);
 318         }
 319         return val;
 320 }
 321
 322 static ssize_t
 323 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 324 {
 325         DECLARE_COMPLETION_ONSTACK (done);
 326         int value;
 327
 328         spin_lock_irq (&epdata->dev->lock);
 329         if (likely (epdata->ep != NULL)) {
 330                 struct usb_request      *req = epdata->req;
 331
 332                 req->context = &done;
 333                 req->complete = epio_complete;
 334                 req->buf = buf;
 335                 req->length = len;
 336                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 337         } else
 338                 value = -ENODEV;
 339         spin_unlock_irq (&epdata->dev->lock);
 340
 341         if (likely (value == 0)) {
 342                 value = wait_event_interruptible (done.wait, done.done);
 343                 if (value != 0) {
 344                         spin_lock_irq (&epdata->dev->lock);
 345                         if (likely (epdata->ep != NULL)) {
 346                                 DBG (epdata->dev, "%s i/o interrupted\n",
 347                                                 epdata->name);
 348                                 usb_ep_dequeue (epdata->ep, epdata->req);
 349                                 spin_unlock_irq (&epdata->dev->lock);
 350
 351                                 wait_event (done.wait, done.done);
 352                                 if (epdata->status == -ECONNRESET)
 353                                         epdata->status = -EINTR;
 354                         } else {
 355                                 spin_unlock_irq (&epdata->dev->lock);
 356
 357                                 DBG (epdata->dev, "endpoint gone\n");
 358                                 epdata->status = -ENODEV;
 359                         }
 360                 }
 361                 return epdata->status;
 362         }
 363         return value;
 364 }
 365
 366
 367 /* handle a synchronous OUT bulk/intr/iso transfer */
 368 static ssize_t
 369 ep_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 370 {
 371         struct ep_data          *data = fd->private_data;
 372         void                    *kbuf;
 373         ssize_t                 value;
 374
 375         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
 376                 return value;
 377
 378         /* halt any endpoint by doing a "wrong direction" i/o call */
 379         if (usb_endpoint_dir_in(&data->desc)) {
 380                 if (usb_endpoint_xfer_isoc(&data->desc)) {
 381                         mutex_unlock(&data->lock);
 382                         return -EINVAL;
 383                 }
 384                 DBG (data->dev, "%s halt\n", data->name);
 385                 spin_lock_irq (&data->dev->lock);
 386                 if (likely (data->ep != NULL))
 387                         usb_ep_set_halt (data->ep);
 388                 spin_unlock_irq (&data->dev->lock);
 389                 mutex_unlock(&data->lock);
 390                 return -EBADMSG;
 391         }
 392
 393         /* FIXME readahead for O_NONBLOCK and poll(); careful with ZLPs */
 394
 395         value = -ENOMEM;
 396         kbuf = kmalloc (len, GFP_KERNEL);
 397         if (unlikely (!kbuf))
 398                 goto free1;
 399
 400         value = ep_io (data, kbuf, len);
 401         VDEBUG (data->dev, "%s read %zu OUT, status %d\n",
 402                 data->name, len, (int) value);
 403         if (value >= 0 && copy_to_user (buf, kbuf, value))
 404                 value = -EFAULT;
 405
 406 free1:
 407         mutex_unlock(&data->lock);
 408         kfree (kbuf);
 409         return value;
 410 }
 411
 412 /* handle a synchronous IN bulk/intr/iso transfer */
 413 static ssize_t
 414 ep_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 415 {
 416         struct ep_data          *data = fd->private_data;
 417         void                    *kbuf;
 418         ssize_t                 value;
 419
 420         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
 421                 return value;
 422
 423         /* halt any endpoint by doing a "wrong direction" i/o call */
 424         if (!usb_endpoint_dir_in(&data->desc)) {
 425                 if (usb_endpoint_xfer_isoc(&data->desc)) {
 426                         mutex_unlock(&data->lock);
 427                         return -EINVAL;
 428                 }
 429                 DBG (data->dev, "%s halt\n", data->name);
 430                 spin_lock_irq (&data->dev->lock);
 431                 if (likely (data->ep != NULL))
 432                         usb_ep_set_halt (data->ep);
 433                 spin_unlock_irq (&data->dev->lock);
 434                 mutex_unlock(&data->lock);
 435                 return -EBADMSG;
 436         }
 437
 438         /* FIXME writebehind for O_NONBLOCK and poll(), qlen = 1 */
 439
 440         value = -ENOMEM;
 441         kbuf = kmalloc (len, GFP_KERNEL);
 442         if (!kbuf)
 443                 goto free1;
 444         if (copy_from_user (kbuf, buf, len)) {
 445                 value = -EFAULT;
 446                 goto free1;
 447         }
 448
 449         value = ep_io (data, kbuf, len);
 450         VDEBUG (data->dev, "%s write %zu IN, status %d\n",
 451                 data->name, len, (int) value);
 452 free1:
 453         mutex_unlock(&data->lock);
 454         kfree (kbuf);
 455         return value;
 456 }
 457
 458 static int
 459 ep_release (struct inode *inode, struct file *fd)
 460 {
 461         struct ep_data          *data = fd->private_data;
 462         int value;
 463
 464         value = mutex_lock_interruptible(&data->lock);
 465         if (value < 0)
 466                 return value;
 467
 468         /* clean up if this can be reopened */
 469         if (data->state != STATE_EP_UNBOUND) {
 470                 data->state = STATE_EP_DISABLED;
 471                 data->desc.bDescriptorType = 0;
 472                 data->hs_desc.bDescriptorType = 0;
 473                 usb_ep_disable(data->ep);
 474         }
 475         mutex_unlock(&data->lock);
 476         put_ep (data);
 477         return 0;
 478 }
 479
 480 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 481 {
 482         struct ep_data          *data = fd->private_data;
 483         int                     status;
 484
 485         if ((status = get_ready_ep (fd->f_flags, data)) < 0)
 486                 return status;
 487
 488         spin_lock_irq (&data->dev->lock);
 489         if (likely (data->ep != NULL)) {
 490                 switch (code) {
 491                 case GADGETFS_FIFO_STATUS:
 492                         status = usb_ep_fifo_status (data->ep);
 493                         break;
 494                 case GADGETFS_FIFO_FLUSH:
 495                         usb_ep_fifo_flush (data->ep);
 496                         break;
 497                 case GADGETFS_CLEAR_HALT:
 498                         status = usb_ep_clear_halt (data->ep);
 499                         break;
 500                 default:
 501                         status = -ENOTTY;
 502                 }
 503         } else
 504                 status = -ENODEV;
 505         spin_unlock_irq (&data->dev->lock);
 506         mutex_unlock(&data->lock);
 507         return status;
 508 }
 509
 510 /*----------------------------------------------------------------------*/
 511
 512 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 513
 514 struct kiocb_priv {
 515         struct usb_request      *req;
 516         struct ep_data          *epdata;
 517         void                    *buf;
 518         const struct iovec      *iv;
 519         unsigned long           nr_segs;
 520         unsigned                actual;
 521 };
 522
 523 static int ep_aio_cancel(struct kiocb *iocb, struct io_event *e)
 524 {
 525         struct kiocb_priv       *priv = iocb->private;
 526         struct ep_data          *epdata;
 527         int                     value;
 528
 529         local_irq_disable();
 530         epdata = priv->epdata;
 531         // spin_lock(&epdata->dev->lock);
 532         kiocbSetCancelled(iocb);
 533         if (likely(epdata && epdata->ep && priv->req))
 534                 value = usb_ep_dequeue (epdata->ep, priv->req);
 535         else
 536                 value = -EINVAL;
 537         // spin_unlock(&epdata->dev->lock);
 538         local_irq_enable();
 539
 540         aio_put_req(iocb);
 541         return value;
 542 }
 543
 544 static ssize_t ep_aio_read_retry(struct kiocb *iocb)
 545 {
 546         struct kiocb_priv       *priv = iocb->private;
 547         ssize_t                 len, total;
 548         void                    *to_copy;
 549         int                     i;
 550
 551         /* we "retry" to get the right mm context for this: */
 552
 553         /* copy stuff into user buffers */
 554         total = priv->actual;
 555         len = 0;
 556         to_copy = priv->buf;
 557         for (i=0; i < priv->nr_segs; i++) {
 558                 ssize_t this = min((ssize_t)(priv->iv[i].iov_len), total);
 559
 560                 if (copy_to_user(priv->iv[i].iov_base, to_copy, this)) {
 561                         if (len == 0)
 562                                 len = -EFAULT;
 563                         break;
 564                 }
 565
 566                 total -= this;
 567                 len += this;
 568                 to_copy += this;
 569                 if (total == 0)
 570                         break;
 571         }
 572         kfree(priv->buf);
 573         kfree(priv->iv);
 574         kfree(priv);
 575         return len;
 576 }
 577
 578 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 579 {
 580         struct kiocb            *iocb = req->context;
 581         struct kiocb_priv       *priv = iocb->private;
 582         struct ep_data          *epdata = priv->epdata;
 583
 584         /* lock against disconnect (and ideally, cancel) */
 585         spin_lock(&epdata->dev->lock);
 586         priv->req = NULL;
 587         priv->epdata = NULL;
 588
 589         /* if this was a write or a read returning no data then we
 590          * don't need to copy anything to userspace, so we can
 591          * complete the aio request immediately.
 592          */
 593         if (priv->iv == NULL || unlikely(req->actual == 0)) {
 594                 kfree(req->buf);
 595                 kfree(priv->iv);
 596                 kfree(priv);
 597                 iocb->private = NULL;
 598                 /* aio_complete() reports bytes-transferred _and_ faults */
 599                 aio_complete(iocb, req->actual ? req->actual : req->status,
 600                                 req->status);
 601         } else {
 602                 /* retry() won't report both; so we hide some faults */
 603                 if (unlikely(0 != req->status))
 604                         DBG(epdata->dev, "%s fault %d len %d\n",
 605                                 ep->name, req->status, req->actual);
 606
 607                 priv->buf = req->buf;
 608                 priv->actual = req->actual;
 609                 kick_iocb(iocb);
 610         }
 611         spin_unlock(&epdata->dev->lock);
 612
 613         usb_ep_free_request(ep, req);
 614         put_ep(epdata);
 615 }
 616
 617 static ssize_t
 618 ep_aio_rwtail(
 619         struct kiocb    *iocb,
 620         char            *buf,
 621         size_t          len,
 622         struct ep_data  *epdata,
 623         const struct iovec *iv,
 624         unsigned long   nr_segs
 625 )
 626 {
 627         struct kiocb_priv       *priv;
 628         struct usb_request      *req;
 629         ssize_t                 value;
 630
 631         priv = kzalloc(sizeof *priv, GFP_KERNEL);
 632         if (!priv) {
 633                 value = -ENOMEM;
 634 fail:
 635                 kfree(buf);
 636                 return value;
 637         }
 638         iocb->private = priv;
 639         if (iv) {
 640                 priv->iv = kmemdup(iv, nr_segs * sizeof(struct iovec),
 641                                    GFP_KERNEL);
 642                 if (!priv->iv) {
 643                         value = -ENOMEM;
 644                         kfree(priv);
 645                         goto fail;
 646                 }
 647         }
 648         priv->nr_segs = nr_segs;
 649
 650         value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
 651         if (unlikely(value < 0)) {
 652                 kfree(priv->iv);
 653                 kfree(priv);
 654                 goto fail;
 655         }
 656
 657         iocb->ki_cancel = ep_aio_cancel;
 658         get_ep(epdata);
 659         priv->epdata = epdata;
 660         priv->actual = 0;
 661
 662         /* each kiocb is coupled to one usb_request, but we can't
 663          * allocate or submit those if the host disconnected.
 664          */
 665         spin_lock_irq(&epdata->dev->lock);
 666         if (likely(epdata->ep)) {
 667                 req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 668                 if (likely(req)) {
 669                         priv->req = req;
 670                         req->buf = buf;
 671                         req->length = len;
 672                         req->complete = ep_aio_complete;
 673                         req->context = iocb;
 674                         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 675                         if (unlikely(0 != value))
 676                                 usb_ep_free_request(epdata->ep, req);
 677                 } else
 678                         value = -EAGAIN;
 679         } else
 680                 value = -ENODEV;
 681         spin_unlock_irq(&epdata->dev->lock);
 682
 683         mutex_unlock(&epdata->lock);
 684
 685         if (unlikely(value)) {
 686                 kfree(priv->iv);
 687                 kfree(priv);
 688                 put_ep(epdata);
 689         } else
 690                 value = (iv ? -EIOCBRETRY : -EIOCBQUEUED);
 691         return value;
 692 }
 693
 694 static ssize_t
 695 ep_aio_read(struct kiocb *iocb, const struct iovec *iov,
 696                 unsigned long nr_segs, loff_t o)
 697 {
 698         struct ep_data          *epdata = iocb->ki_filp->private_data;
 699         char                    *buf;
 700
 701         if (unlikely(usb_endpoint_dir_in(&epdata->desc)))
 702                 return -EINVAL;
 703
 704         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 705         if (unlikely(!buf))
 706                 return -ENOMEM;
 707
 708         iocb->ki_retry = ep_aio_read_retry;
 709         return ep_aio_rwtail(iocb, buf, iocb->ki_left, epdata, iov, nr_segs);
 710 }
 711
 712 static ssize_t
 713 ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
 714                 unsigned long nr_segs, loff_t o)
 715 {
 716         struct ep_data          *epdata = iocb->ki_filp->private_data;
 717         char                    *buf;
 718         size_t                  len = 0;
 719         int                     i = 0;
 720
 721         if (unlikely(!usb_endpoint_dir_in(&epdata->desc)))
 722                 return -EINVAL;
 723
 724         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 725         if (unlikely(!buf))
 726                 return -ENOMEM;
 727
 728         for (i=0; i < nr_segs; i++) {
 729                 if (unlikely(copy_from_user(&buf[len], iov[i].iov_base,
 730                                 iov[i].iov_len) != 0)) {
 731                         kfree(buf);
 732                         return -EFAULT;
 733                 }
 734                 len += iov[i].iov_len;
 735         }
 736         return ep_aio_rwtail(iocb, buf, len, epdata, NULL, 0);
 737 }
 738
 739 /*----------------------------------------------------------------------*/
 740
 741 /* used after endpoint configuration */
 742 static const struct file_operations ep_io_operations = {
 743         .owner =        THIS_MODULE,
 744         .llseek =       no_llseek,
 745
 746         .read =         ep_read,
 747         .write =        ep_write,
 748         .unlocked_ioctl = ep_ioctl,
 749         .release =      ep_release,
 750
 751         .aio_read =     ep_aio_read,
 752         .aio_write =    ep_aio_write,
 753 };
 754
 755 /* ENDPOINT INITIALIZATION
 756  *
 757  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 758  *     status = write (fd, descriptors, sizeof descriptors)
 759  *
 760  * That write establishes the endpoint configuration, configuring
 761  * the controller to process bulk, interrupt, or isochronous transfers
 762  * at the right maxpacket size, and so on.
 763  *
 764  * The descriptors are message type 1, identified by a host order u32
 765  * at the beginning of what's written.  Descriptor order is: full/low
 766  * speed descriptor, then optional high speed descriptor.
 767  */
 768 static ssize_t
 769 ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 770 {
 771         struct ep_data          *data = fd->private_data;
 772         struct usb_ep           *ep;
 773         u32                     tag;
 774         int                     value, length = len;
 775
 776         value = mutex_lock_interruptible(&data->lock);
 777         if (value < 0)
 778                 return value;
 779
 780         if (data->state != STATE_EP_READY) {
 781                 value = -EL2HLT;
 782                 goto fail;
 783         }
 784
 785         value = len;
 786         if (len < USB_DT_ENDPOINT_SIZE + 4)
 787                 goto fail0;
 788
 789         /* we might need to change message format someday */
 790         if (copy_from_user (&tag, buf, 4)) {
 791                 goto fail1;
 792         }
 793         if (tag != 1) {
 794                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 795                 goto fail0;
 796         }
 797         buf += 4;
 798         len -= 4;
 799
 800         /* NOTE:  audio endpoint extensions not accepted here;
 801          * just don't include the extra bytes.
 802          */
 803
 804         /* full/low speed descriptor, then high speed */
 805         if (copy_from_user (&data->desc, buf, USB_DT_ENDPOINT_SIZE)) {
 806                 goto fail1;
 807         }
 808         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 809                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 810                 goto fail0;
 811         if (len != USB_DT_ENDPOINT_SIZE) {
 812                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 813                         goto fail0;
 814                 if (copy_from_user (&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 815                                         USB_DT_ENDPOINT_SIZE)) {
 816                         goto fail1;
 817                 }
 818                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 819                                 || data->hs_desc.bDescriptorType
 820                                         != USB_DT_ENDPOINT) {
 821                         DBG(data->dev, "config %s, bad hs length or type\n",
 822                                         data->name);
 823                         goto fail0;
 824                 }
 825         }
 826
 827         spin_lock_irq (&data->dev->lock);
 828         if (data->dev->state == STATE_DEV_UNBOUND) {
 829                 value = -ENOENT;
 830                 goto gone;
 831         } else if ((ep = data->ep) == NULL) {
 832                 value = -ENODEV;
 833                 goto gone;
 834         }
 835         switch (data->dev->gadget->speed) {
 836         case USB_SPEED_LOW:
 837         case USB_SPEED_FULL:
 838                 ep->desc = &data->desc;
 839                 value = usb_ep_enable(ep);
 840                 if (value == 0)
 841                         data->state = STATE_EP_ENABLED;
 842                 break;
 843 #ifdef  CONFIG_USB_GADGET_DUALSPEED
 844         case USB_SPEED_HIGH:
 845                 /* fails if caller didn't provide that descriptor... */
 846                 ep->desc = &data->hs_desc;
 847                 value = usb_ep_enable(ep);
 848                 if (value == 0)
 849                         data->state = STATE_EP_ENABLED;
 850                 break;
 851 #endif
 852         default:
 853                 DBG(data->dev, "unconnected, %s init abandoned\n",
 854                                 data->name);
 855                 value = -EINVAL;
 856         }
 857         if (value == 0) {
 858                 fd->f_op = &ep_io_operations;
 859                 value = length;
 860         }
 861 gone:
 862         spin_unlock_irq (&data->dev->lock);
 863         if (value < 0) {
 864 fail:
 865                 data->desc.bDescriptorType = 0;
 866                 data->hs_desc.bDescriptorType = 0;
 867         }
 868         mutex_unlock(&data->lock);
 869         return value;
 870 fail0:
 871         value = -EINVAL;
 872         goto fail;
 873 fail1:
 874         value = -EFAULT;
 875         goto fail;
 876 }
 877
 878 static int
 879 ep_open (struct inode *inode, struct file *fd)
 880 {
 881         struct ep_data          *data = inode->i_private;
 882         int                     value = -EBUSY;
 883
 884         if (mutex_lock_interruptible(&data->lock) != 0)
 885                 return -EINTR;
 886         spin_lock_irq (&data->dev->lock);
 887         if (data->dev->state == STATE_DEV_UNBOUND)
 888                 value = -ENOENT;
 889         else if (data->state == STATE_EP_DISABLED) {
 890                 value = 0;
 891                 data->state = STATE_EP_READY;
 892                 get_ep (data);
 893                 fd->private_data = data;
 894                 VDEBUG (data->dev, "%s ready\n", data->name);
 895         } else
 896                 DBG (data->dev, "%s state %d\n",
 897                         data->name, data->state);
 898         spin_unlock_irq (&data->dev->lock);
 899         mutex_unlock(&data->lock);
 900         return value;
 901 }
 902
 903 /* used before endpoint configuration */
 904 static const struct file_operations ep_config_operations = {
 905         .owner =        THIS_MODULE,
 906         .llseek =       no_llseek,
 907
 908         .open =         ep_open,
 909         .write =        ep_config,
 910         .release =      ep_release,
 911 };
 912
 913 /*----------------------------------------------------------------------*/
 914
 915 /* EP0 IMPLEMENTATION can be partly in userspace.
 916  *
 917  * Drivers that use this facility receive various events, including
 918  * control requests the kernel doesn't handle.  Drivers that don't
 919  * use this facility may be too simple-minded for real applications.
 920  */
 921
 922 static inline void ep0_readable (struct dev_data *dev)
 923 {
 924         wake_up (&dev->wait);
 925         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 926 }
 927
 928 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 929 {
 930         struct dev_data         *dev = ep->driver_data;
 931
 932         if (req->buf != dev->rbuf) {
 933                 kfree(req->buf);
 934                 req->buf = dev->rbuf;
 935                 req->dma = DMA_ADDR_INVALID;
 936         }
 937         req->complete = epio_complete;
 938         dev->setup_out_ready = 0;
 939 }
 940
 941 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 942 {
 943         struct dev_data         *dev = ep->driver_data;
 944         unsigned long           flags;
 945         int                     free = 1;
 946
 947         /* for control OUT, data must still get to userspace */
 948         spin_lock_irqsave(&dev->lock, flags);
 949         if (!dev->setup_in) {
 950                 dev->setup_out_error = (req->status != 0);
 951                 if (!dev->setup_out_error)
 952                         free = 0;
 953                 dev->setup_out_ready = 1;
 954                 ep0_readable (dev);
 955         }
 956
 957         /* clean up as appropriate */
 958         if (free && req->buf != &dev->rbuf)
 959                 clean_req (ep, req);
 960         req->complete = epio_complete;
 961         spin_unlock_irqrestore(&dev->lock, flags);
 962 }
 963
 964 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 965 {
 966         struct dev_data *dev = ep->driver_data;
 967
 968         if (dev->setup_out_ready) {
 969                 DBG (dev, "ep0 request busy!\n");
 970                 return -EBUSY;
 971         }
 972         if (len > sizeof (dev->rbuf))
 973                 req->buf = kmalloc(len, GFP_ATOMIC);
 974         if (req->buf == NULL) {
 975                 req->buf = dev->rbuf;
 976                 return -ENOMEM;
 977         }
 978         req->complete = ep0_complete;
 979         req->length = len;
 980         req->zero = 0;
 981         return 0;
 982 }
 983
 984 static ssize_t
 985 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 986 {
 987         struct dev_data                 *dev = fd->private_data;
 988         ssize_t                         retval;
 989         enum ep0_state                  state;
 990
 991         spin_lock_irq (&dev->lock);
 992
 993         /* report fd mode change before acting on it */
 994         if (dev->setup_abort) {
 995                 dev->setup_abort = 0;
 996                 retval = -EIDRM;
 997                 goto done;
 998         }
 999
1000         /* control DATA stage */
1001         if ((state = dev->state) == STATE_DEV_SETUP) {
1002
1003                 if (dev->setup_in) {            /* stall IN */
1004                         VDEBUG(dev, "ep0in stall\n");
1005                         (void) usb_ep_set_halt (dev->gadget->ep0);
1006                         retval = -EL2HLT;
1007                         dev->state = STATE_DEV_CONNECTED;
1008
1009                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
1010                         struct usb_ep           *ep = dev->gadget->ep0;
1011                         struct usb_request      *req = dev->req;
1012
1013                         if ((retval = setup_req (ep, req, 0)) == 0)
1014                                 retval = usb_ep_queue (ep, req, GFP_ATOMIC);
1015                         dev->state = STATE_DEV_CONNECTED;
1016
1017                         /* assume that was SET_CONFIGURATION */
1018                         if (dev->current_config) {
1019                                 unsigned power;
1020
1021                                 if (gadget_is_dualspeed(dev->gadget)
1022                                                 && (dev->gadget->speed
1023                                                         == USB_SPEED_HIGH))
1024                                         power = dev->hs_config->bMaxPower;
1025                                 else
1026                                         power = dev->config->bMaxPower;
1027                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
1028                         }
1029
1030                 } else {                        /* collect OUT data */
1031                         if ((fd->f_flags & O_NONBLOCK) != 0
1032                                         && !dev->setup_out_ready) {
1033                                 retval = -EAGAIN;
1034                                 goto done;
1035                         }
1036                         spin_unlock_irq (&dev->lock);
1037                         retval = wait_event_interruptible (dev->wait,
1038                                         dev->setup_out_ready != 0);
1039
1040                         /* FIXME state could change from under us */
1041                         spin_lock_irq (&dev->lock);
1042                         if (retval)
1043                                 goto done;
1044
1045                         if (dev->state != STATE_DEV_SETUP) {
1046                                 retval = -ECANCELED;
1047                                 goto done;
1048                         }
1049                         dev->state = STATE_DEV_CONNECTED;
1050
1051                         if (dev->setup_out_error)
1052                                 retval = -EIO;
1053                         else {
1054                                 len = min (len, (size_t)dev->req->actual);
1055 // FIXME don't call this with the spinlock held ...
1056                                 if (copy_to_user (buf, dev->req->buf, len))
1057                                         retval = -EFAULT;
1058                                 else
1059                                         retval = len;
1060                                 clean_req (dev->gadget->ep0, dev->req);
1061                                 /* NOTE userspace can't yet choose to stall */
1062                         }
1063                 }
1064                 goto done;
1065         }
1066
1067         /* else normal: return event data */
1068         if (len < sizeof dev->event [0]) {
1069                 retval = -EINVAL;
1070                 goto done;
1071         }
1072         len -= len % sizeof (struct usb_gadgetfs_event);
1073         dev->usermode_setup = 1;
1074
1075 scan:
1076         /* return queued events right away */
1077         if (dev->ev_next != 0) {
1078                 unsigned                i, n;
1079
1080                 n = len / sizeof (struct usb_gadgetfs_event);
1081                 if (dev->ev_next < n)
1082                         n = dev->ev_next;
1083
1084                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1085                 for (i = 0; i < n; i++) {
1086                         if (dev->event [i].type == GADGETFS_SETUP) {
1087                                 dev->state = STATE_DEV_SETUP;
1088                                 n = i + 1;
1089                                 break;
1090                         }
1091                 }
1092                 spin_unlock_irq (&dev->lock);
1093                 len = n * sizeof (struct usb_gadgetfs_event);
1094                 if (copy_to_user (buf, &dev->event, len))
1095                         retval = -EFAULT;
1096                 else
1097                         retval = len;
1098                 if (len > 0) {
1099                         /* NOTE this doesn't guard against broken drivers;
1100                          * concurrent ep0 readers may lose events.
1101                          */
1102                         spin_lock_irq (&dev->lock);
1103                         if (dev->ev_next > n) {
1104                                 memmove(&dev->event[0], &dev->event[n],
1105                                         sizeof (struct usb_gadgetfs_event)
1106                                                 * (dev->ev_next - n));
1107                         }
1108                         dev->ev_next -= n;
1109                         spin_unlock_irq (&dev->lock);
1110                 }
1111                 return retval;
1112         }
1113         if (fd->f_flags & O_NONBLOCK) {
1114                 retval = -EAGAIN;
1115                 goto done;
1116         }
1117
1118         switch (state) {
1119         default:
1120                 DBG (dev, "fail %s, state %d\n", __func__, state);
1121                 retval = -ESRCH;
1122                 break;
1123         case STATE_DEV_UNCONNECTED:
1124         case STATE_DEV_CONNECTED:
1125                 spin_unlock_irq (&dev->lock);
1126                 DBG (dev, "%s wait\n", __func__);
1127
1128                 /* wait for events */
1129                 retval = wait_event_interruptible (dev->wait,
1130                                 dev->ev_next != 0);
1131                 if (retval < 0)
1132                         return retval;
1133                 spin_lock_irq (&dev->lock);
1134                 goto scan;
1135         }
1136
1137 done:
1138         spin_unlock_irq (&dev->lock);
1139         return retval;
1140 }
1141
1142 static struct usb_gadgetfs_event *
1143 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1144 {
1145         struct usb_gadgetfs_event       *event;
1146         unsigned                        i;
1147
1148         switch (type) {
1149         /* these events purge the queue */
1150         case GADGETFS_DISCONNECT:
1151                 if (dev->state == STATE_DEV_SETUP)
1152                         dev->setup_abort = 1;
1153                 // FALL THROUGH
1154         case GADGETFS_CONNECT:
1155                 dev->ev_next = 0;
1156                 break;
1157         case GADGETFS_SETUP:            /* previous request timed out */
1158         case GADGETFS_SUSPEND:          /* same effect */
1159                 /* these events can't be repeated */
1160                 for (i = 0; i != dev->ev_next; i++) {
1161                         if (dev->event [i].type != type)
1162                                 continue;
1163                         DBG(dev, "discard old event[%d] %d\n", i, type);
1164                         dev->ev_next--;
1165                         if (i == dev->ev_next)
1166                                 break;
1167                         /* indices start at zero, for simplicity */
1168                         memmove (&dev->event [i], &dev->event [i + 1],
1169                                 sizeof (struct usb_gadgetfs_event)
1170                                         * (dev->ev_next - i));
1171                 }
1172                 break;
1173         default:
1174                 BUG ();
1175         }
1176         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1177         event = &dev->event [dev->ev_next++];
1178         BUG_ON (dev->ev_next > N_EVENT);
1179         memset (event, 0, sizeof *event);
1180         event->type = type;
1181         return event;
1182 }
1183
1184 static ssize_t
1185 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1186 {
1187         struct dev_data         *dev = fd->private_data;
1188         ssize_t                 retval = -ESRCH;
1189
1190         spin_lock_irq (&dev->lock);
1191
1192         /* report fd mode change before acting on it */
1193         if (dev->setup_abort) {
1194                 dev->setup_abort = 0;
1195                 retval = -EIDRM;
1196
1197         /* data and/or status stage for control request */
1198         } else if (dev->state == STATE_DEV_SETUP) {
1199
1200                 len = min_t(size_t, len, dev->setup_wLength);
1201                 if (dev->setup_in) {
1202                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1203                         if (retval == 0) {
1204                                 dev->state = STATE_DEV_CONNECTED;
1205                                 spin_unlock_irq (&dev->lock);
1206                                 if (copy_from_user (dev->req->buf, buf, len))
1207                                         retval = -EFAULT;
1208                                 else {
1209                                         if (len < dev->setup_wLength)
1210                                                 dev->req->zero = 1;
1211                                         retval = usb_ep_queue (
1212                                                 dev->gadget->ep0, dev->req,
1213                                                 GFP_KERNEL);
1214                                 }
1215                                 if (retval < 0) {
1216                                         spin_lock_irq (&dev->lock);
1217                                         clean_req (dev->gadget->ep0, dev->req);
1218                                         spin_unlock_irq (&dev->lock);
1219                                 } else
1220                                         retval = len;
1221
1222                                 return retval;
1223                         }
1224
1225                 /* can stall some OUT transfers */
1226                 } else if (dev->setup_can_stall) {
1227                         VDEBUG(dev, "ep0out stall\n");
1228                         (void) usb_ep_set_halt (dev->gadget->ep0);
1229                         retval = -EL2HLT;
1230                         dev->state = STATE_DEV_CONNECTED;
1231                 } else {
1232                         DBG(dev, "bogus ep0out stall!\n");
1233                 }
1234         } else
1235                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1236
1237         spin_unlock_irq (&dev->lock);
1238         return retval;
1239 }
1240
1241 static int
1242 ep0_fasync (int f, struct file *fd, int on)
1243 {
1244         struct dev_data         *dev = fd->private_data;
1245         // caller must F_SETOWN before signal delivery happens
1246         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1247         return fasync_helper (f, fd, on, &dev->fasync);
1248 }
1249
1250 static struct usb_gadget_driver gadgetfs_driver;
1251
1252 static int
1253 dev_release (struct inode *inode, struct file *fd)
1254 {
1255         struct dev_data         *dev = fd->private_data;
1256
1257         /* closing ep0 === shutdown all */
1258
1259         usb_gadget_unregister_driver (&gadgetfs_driver);
1260
1261         /* at this point "good" hardware has disconnected the
1262          * device from USB; the host won't see it any more.
1263          * alternatively, all host requests will time out.
1264          */
1265
1266         kfree (dev->buf);
1267         dev->buf = NULL;
1268         put_dev (dev);
1269
1270         /* other endpoints were all decoupled from this device */
1271         spin_lock_irq(&dev->lock);
1272         dev->state = STATE_DEV_DISABLED;
1273         spin_unlock_irq(&dev->lock);
1274         return 0;
1275 }
1276
1277 static unsigned int
1278 ep0_poll (struct file *fd, poll_table *wait)
1279 {
1280        struct dev_data         *dev = fd->private_data;
1281        int                     mask = 0;
1282
1283        poll_wait(fd, &dev->wait, wait);
1284
1285        spin_lock_irq (&dev->lock);
1286
1287        /* report fd mode change before acting on it */
1288        if (dev->setup_abort) {
1289                dev->setup_abort = 0;
1290                mask = POLLHUP;
1291                goto out;
1292        }
1293
1294        if (dev->state == STATE_DEV_SETUP) {
1295                if (dev->setup_in || dev->setup_can_stall)
1296                        mask = POLLOUT;
1297        } else {
1298                if (dev->ev_next != 0)
1299                        mask = POLLIN;
1300        }
1301 out:
1302        spin_unlock_irq(&dev->lock);
1303        return mask;
1304 }
1305
1306 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1307 {
1308         struct dev_data         *dev = fd->private_data;
1309         struct usb_gadget       *gadget = dev->gadget;
1310         long ret = -ENOTTY;
1311
1312         if (gadget->ops->ioctl)
1313                 ret = gadget->ops->ioctl (gadget, code, value);
1314
1315         return ret;
1316 }
1317
1318 /* used after device configuration */
1319 static const struct file_operations ep0_io_operations = {
1320         .owner =        THIS_MODULE,
1321         .llseek =       no_llseek,
1322
1323         .read =         ep0_read,
1324         .write =        ep0_write,
1325         .fasync =       ep0_fasync,
1326         .poll =         ep0_poll,
1327         .unlocked_ioctl =       dev_ioctl,
1328         .release =      dev_release,
1329 };
1330
1331 /*----------------------------------------------------------------------*/
1332
1333 /* The in-kernel gadget driver handles most ep0 issues, in particular
1334  * enumerating the single configuration (as provided from user space).
1335  *
1336  * Unrecognized ep0 requests may be handled in user space.
1337  */
1338
1339 #ifdef  CONFIG_USB_GADGET_DUALSPEED
1340 static void make_qualifier (struct dev_data *dev)
1341 {
1342         struct usb_qualifier_descriptor         qual;
1343         struct usb_device_descriptor            *desc;
1344
1345         qual.bLength = sizeof qual;
1346         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1347         qual.bcdUSB = cpu_to_le16 (0x0200);
1348
1349         desc = dev->dev;
1350         qual.bDeviceClass = desc->bDeviceClass;
1351         qual.bDeviceSubClass = desc->bDeviceSubClass;
1352         qual.bDeviceProtocol = desc->bDeviceProtocol;
1353
1354         /* assumes ep0 uses the same value for both speeds ... */
1355         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1356
1357         qual.bNumConfigurations = 1;
1358         qual.bRESERVED = 0;
1359
1360         memcpy (dev->rbuf, &qual, sizeof qual);
1361 }
1362 #endif
1363
1364 static int
1365 config_buf (struct dev_data *dev, u8 type, unsigned index)
1366 {
1367         int             len;
1368         int             hs = 0;
1369
1370         /* only one configuration */
1371         if (index > 0)
1372                 return -EINVAL;
1373
1374         if (gadget_is_dualspeed(dev->gadget)) {
1375                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1376                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1377                         hs = !hs;
1378         }
1379         if (hs) {
1380                 dev->req->buf = dev->hs_config;
1381                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1382         } else {
1383                 dev->req->buf = dev->config;
1384                 len = le16_to_cpu(dev->config->wTotalLength);
1385         }
1386         ((u8 *)dev->req->buf) [1] = type;
1387         return len;
1388 }
1389
1390 static int
1391 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1392 {
1393         struct dev_data                 *dev = get_gadget_data (gadget);
1394         struct usb_request              *req = dev->req;
1395         int                             value = -EOPNOTSUPP;
1396         struct usb_gadgetfs_event       *event;
1397         u16                             w_value = le16_to_cpu(ctrl->wValue);
1398         u16                             w_length = le16_to_cpu(ctrl->wLength);
1399
1400         spin_lock (&dev->lock);
1401         dev->setup_abort = 0;
1402         if (dev->state == STATE_DEV_UNCONNECTED) {
1403                 if (gadget_is_dualspeed(gadget)
1404                                 && gadget->speed == USB_SPEED_HIGH
1405                                 && dev->hs_config == NULL) {
1406                         spin_unlock(&dev->lock);
1407                         ERROR (dev, "no high speed config??\n");
1408                         return -EINVAL;
1409                 }
1410
1411                 dev->state = STATE_DEV_CONNECTED;
1412
1413                 INFO (dev, "connected\n");
1414                 event = next_event (dev, GADGETFS_CONNECT);
1415                 event->u.speed = gadget->speed;
1416                 ep0_readable (dev);
1417
1418         /* host may have given up waiting for response.  we can miss control
1419          * requests handled lower down (device/endpoint status and features);
1420          * then ep0_{read,write} will report the wrong status. controller
1421          * driver will have aborted pending i/o.
1422          */
1423         } else if (dev->state == STATE_DEV_SETUP)
1424                 dev->setup_abort = 1;
1425
1426         req->buf = dev->rbuf;
1427         req->dma = DMA_ADDR_INVALID;
1428         req->context = NULL;
1429         value = -EOPNOTSUPP;
1430         switch (ctrl->bRequest) {
1431
1432         case USB_REQ_GET_DESCRIPTOR:
1433                 if (ctrl->bRequestType != USB_DIR_IN)
1434                         goto unrecognized;
1435                 switch (w_value >> 8) {
1436
1437                 case USB_DT_DEVICE:
1438                         value = min (w_length, (u16) sizeof *dev->dev);
1439                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1440                         req->buf = dev->dev;
1441                         break;
1442 #ifdef  CONFIG_USB_GADGET_DUALSPEED
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 #endif
1453                 case USB_DT_CONFIG:
1454                         value = config_buf (dev,
1455                                         w_value >> 8,
1456                                         w_value & 0xff);
1457                         if (value >= 0)
1458                                 value = min (w_length, (u16) value);
1459                         break;
1460                 case USB_DT_STRING:
1461                         goto unrecognized;
1462
1463                 default:                // all others are errors
1464                         break;
1465                 }
1466                 break;
1467
1468         /* currently one config, two speeds */
1469         case USB_REQ_SET_CONFIGURATION:
1470                 if (ctrl->bRequestType != 0)
1471                         goto unrecognized;
1472                 if (0 == (u8) w_value) {
1473                         value = 0;
1474                         dev->current_config = 0;
1475                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1476                         // user mode expected to disable endpoints
1477                 } else {
1478                         u8      config, power;
1479
1480                         if (gadget_is_dualspeed(gadget)
1481                                         && gadget->speed == USB_SPEED_HIGH) {
1482                                 config = dev->hs_config->bConfigurationValue;
1483                                 power = dev->hs_config->bMaxPower;
1484                         } else {
1485                                 config = dev->config->bConfigurationValue;
1486                                 power = dev->config->bMaxPower;
1487                         }
1488
1489                         if (config == (u8) w_value) {
1490                                 value = 0;
1491                                 dev->current_config = config;
1492                                 usb_gadget_vbus_draw(gadget, 2 * power);
1493                         }
1494                 }
1495
1496                 /* report SET_CONFIGURATION like any other control request,
1497                  * except that usermode may not stall this.  the next
1498                  * request mustn't be allowed start until this finishes:
1499                  * endpoints and threads set up, etc.
1500                  *
1501                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1502                  * has bad/racey automagic that prevents synchronizing here.
1503                  * even kernel mode drivers often miss them.
1504                  */
1505                 if (value == 0) {
1506                         INFO (dev, "configuration #%d\n", dev->current_config);
1507                         if (dev->usermode_setup) {
1508                                 dev->setup_can_stall = 0;
1509                                 goto delegate;
1510                         }
1511                 }
1512                 break;
1513
1514 #ifndef CONFIG_USB_GADGET_PXA25X
1515         /* PXA automagically handles this request too */
1516         case USB_REQ_GET_CONFIGURATION:
1517                 if (ctrl->bRequestType != 0x80)
1518                         goto unrecognized;
1519                 *(u8 *)req->buf = dev->current_config;
1520                 value = min (w_length, (u16) 1);
1521                 break;
1522 #endif
1523
1524         default:
1525 unrecognized:
1526                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1527                         dev->usermode_setup ? "delegate" : "fail",
1528                         ctrl->bRequestType, ctrl->bRequest,
1529                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1530
1531                 /* if there's an ep0 reader, don't stall */
1532                 if (dev->usermode_setup) {
1533                         dev->setup_can_stall = 1;
1534 delegate:
1535                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1536                                                 ? 1 : 0;
1537                         dev->setup_wLength = w_length;
1538                         dev->setup_out_ready = 0;
1539                         dev->setup_out_error = 0;
1540                         value = 0;
1541
1542                         /* read DATA stage for OUT right away */
1543                         if (unlikely (!dev->setup_in && w_length)) {
1544                                 value = setup_req (gadget->ep0, dev->req,
1545                                                         w_length);
1546                                 if (value < 0)
1547                                         break;
1548                                 value = usb_ep_queue (gadget->ep0, dev->req,
1549                                                         GFP_ATOMIC);
1550                                 if (value < 0) {
1551                                         clean_req (gadget->ep0, dev->req);
1552                                         break;
1553                                 }
1554
1555                                 /* we can't currently stall these */
1556                                 dev->setup_can_stall = 0;
1557                         }
1558
1559                         /* state changes when reader collects event */
1560                         event = next_event (dev, GADGETFS_SETUP);
1561                         event->u.setup = *ctrl;
1562                         ep0_readable (dev);
1563                         spin_unlock (&dev->lock);
1564                         return 0;
1565                 }
1566         }
1567
1568         /* proceed with data transfer and status phases? */
1569         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1570                 req->length = value;
1571                 req->zero = value < w_length;
1572                 value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
1573                 if (value < 0) {
1574                         DBG (dev, "ep_queue --> %d\n", value);
1575                         req->status = 0;
1576                 }
1577         }
1578
1579         /* device stalls when value < 0 */
1580         spin_unlock (&dev->lock);
1581         return value;
1582 }
1583
1584 static void destroy_ep_files (struct dev_data *dev)
1585 {
1586         struct list_head        *entry, *tmp;
1587
1588         DBG (dev, "%s %d\n", __func__, dev->state);
1589
1590         /* dev->state must prevent interference */
1591 restart:
1592         spin_lock_irq (&dev->lock);
1593         list_for_each_safe (entry, tmp, &dev->epfiles) {
1594                 struct ep_data  *ep;
1595                 struct inode    *parent;
1596                 struct dentry   *dentry;
1597
1598                 /* break link to FS */
1599                 ep = list_entry (entry, struct ep_data, epfiles);
1600                 list_del_init (&ep->epfiles);
1601                 dentry = ep->dentry;
1602                 ep->dentry = NULL;
1603                 parent = dentry->d_parent->d_inode;
1604
1605                 /* break link to controller */
1606                 if (ep->state == STATE_EP_ENABLED)
1607                         (void) usb_ep_disable (ep->ep);
1608                 ep->state = STATE_EP_UNBOUND;
1609                 usb_ep_free_request (ep->ep, ep->req);
1610                 ep->ep = NULL;
1611                 wake_up (&ep->wait);
1612                 put_ep (ep);
1613
1614                 spin_unlock_irq (&dev->lock);
1615
1616                 /* break link to dcache */
1617                 mutex_lock (&parent->i_mutex);
1618                 d_delete (dentry);
1619                 dput (dentry);
1620                 mutex_unlock (&parent->i_mutex);
1621
1622                 /* fds may still be open */
1623                 goto restart;
1624         }
1625         spin_unlock_irq (&dev->lock);
1626 }
1627
1628
1629 static struct inode *
1630 gadgetfs_create_file (struct super_block *sb, char const *name,
1631                 void *data, const struct file_operations *fops,
1632                 struct dentry **dentry_p);
1633
1634 static int activate_ep_files (struct dev_data *dev)
1635 {
1636         struct usb_ep   *ep;
1637         struct ep_data  *data;
1638
1639         gadget_for_each_ep (ep, dev->gadget) {
1640
1641                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1642                 if (!data)
1643                         goto enomem0;
1644                 data->state = STATE_EP_DISABLED;
1645                 mutex_init(&data->lock);
1646                 init_waitqueue_head (&data->wait);
1647
1648                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1649                 atomic_set (&data->count, 1);
1650                 data->dev = dev;
1651                 get_dev (dev);
1652
1653                 data->ep = ep;
1654                 ep->driver_data = data;
1655
1656                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1657                 if (!data->req)
1658                         goto enomem1;
1659
1660                 data->inode = gadgetfs_create_file (dev->sb, data->name,
1661                                 data, &ep_config_operations,
1662                                 &data->dentry);
1663                 if (!data->inode)
1664                         goto enomem2;
1665                 list_add_tail (&data->epfiles, &dev->epfiles);
1666         }
1667         return 0;
1668
1669 enomem2:
1670         usb_ep_free_request (ep, data->req);
1671 enomem1:
1672         put_dev (dev);
1673         kfree (data);
1674 enomem0:
1675         DBG (dev, "%s enomem\n", __func__);
1676         destroy_ep_files (dev);
1677         return -ENOMEM;
1678 }
1679
1680 static void
1681 gadgetfs_unbind (struct usb_gadget *gadget)
1682 {
1683         struct dev_data         *dev = get_gadget_data (gadget);
1684
1685         DBG (dev, "%s\n", __func__);
1686
1687         spin_lock_irq (&dev->lock);
1688         dev->state = STATE_DEV_UNBOUND;
1689         spin_unlock_irq (&dev->lock);
1690
1691         destroy_ep_files (dev);
1692         gadget->ep0->driver_data = NULL;
1693         set_gadget_data (gadget, NULL);
1694
1695         /* we've already been disconnected ... no i/o is active */
1696         if (dev->req)
1697                 usb_ep_free_request (gadget->ep0, dev->req);
1698         DBG (dev, "%s done\n", __func__);
1699         put_dev (dev);
1700 }
1701
1702 static struct dev_data          *the_device;
1703
1704 static int
1705 gadgetfs_bind (struct usb_gadget *gadget)
1706 {
1707         struct dev_data         *dev = the_device;
1708
1709         if (!dev)
1710                 return -ESRCH;
1711         if (0 != strcmp (CHIP, gadget->name)) {
1712                 pr_err("%s expected %s controller not %s\n",
1713                         shortname, CHIP, gadget->name);
1714                 return -ENODEV;
1715         }
1716
1717         set_gadget_data (gadget, dev);
1718         dev->gadget = gadget;
1719         gadget->ep0->driver_data = dev;
1720
1721         /* preallocate control response and buffer */
1722         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1723         if (!dev->req)
1724                 goto enomem;
1725         dev->req->context = NULL;
1726         dev->req->complete = epio_complete;
1727
1728         if (activate_ep_files (dev) < 0)
1729                 goto enomem;
1730
1731         INFO (dev, "bound to %s driver\n", gadget->name);
1732         spin_lock_irq(&dev->lock);
1733         dev->state = STATE_DEV_UNCONNECTED;
1734         spin_unlock_irq(&dev->lock);
1735         get_dev (dev);
1736         return 0;
1737
1738 enomem:
1739         gadgetfs_unbind (gadget);
1740         return -ENOMEM;
1741 }
1742
1743 static void
1744 gadgetfs_disconnect (struct usb_gadget *gadget)
1745 {
1746         struct dev_data         *dev = get_gadget_data (gadget);
1747         unsigned long           flags;
1748
1749         spin_lock_irqsave (&dev->lock, flags);
1750         if (dev->state == STATE_DEV_UNCONNECTED)
1751                 goto exit;
1752         dev->state = STATE_DEV_UNCONNECTED;
1753
1754         INFO (dev, "disconnected\n");
1755         next_event (dev, GADGETFS_DISCONNECT);
1756         ep0_readable (dev);
1757 exit:
1758         spin_unlock_irqrestore (&dev->lock, flags);
1759 }
1760
1761 static void
1762 gadgetfs_suspend (struct usb_gadget *gadget)
1763 {
1764         struct dev_data         *dev = get_gadget_data (gadget);
1765
1766         INFO (dev, "suspended from state %d\n", dev->state);
1767         spin_lock (&dev->lock);
1768         switch (dev->state) {
1769         case STATE_DEV_SETUP:           // VERY odd... host died??
1770         case STATE_DEV_CONNECTED:
1771         case STATE_DEV_UNCONNECTED:
1772                 next_event (dev, GADGETFS_SUSPEND);
1773                 ep0_readable (dev);
1774                 /* FALLTHROUGH */
1775         default:
1776                 break;
1777         }
1778         spin_unlock (&dev->lock);
1779 }
1780
1781 static struct usb_gadget_driver gadgetfs_driver = {
1782 #ifdef  CONFIG_USB_GADGET_DUALSPEED
1783         .speed          = USB_SPEED_HIGH,
1784 #else
1785         .speed          = USB_SPEED_FULL,
1786 #endif
1787         .function       = (char *) driver_desc,
1788         .unbind         = gadgetfs_unbind,
1789         .setup          = gadgetfs_setup,
1790         .disconnect     = gadgetfs_disconnect,
1791         .suspend        = gadgetfs_suspend,
1792
1793         .driver = {
1794                 .name           = (char *) shortname,
1795         },
1796 };
1797
1798 /*----------------------------------------------------------------------*/
1799
1800 static void gadgetfs_nop(struct usb_gadget *arg) { }
1801
1802 static int gadgetfs_probe (struct usb_gadget *gadget)
1803 {
1804         CHIP = gadget->name;
1805         return -EISNAM;
1806 }
1807
1808 static struct usb_gadget_driver probe_driver = {
1809         .speed          = USB_SPEED_HIGH,
1810         .unbind         = gadgetfs_nop,
1811         .setup          = (void *)gadgetfs_nop,
1812         .disconnect     = gadgetfs_nop,
1813         .driver = {
1814                 .name           = "nop",
1815         },
1816 };
1817
1818
1819 /* DEVICE INITIALIZATION
1820  *
1821  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1822  *     status = write (fd, descriptors, sizeof descriptors)
1823  *
1824  * That write establishes the device configuration, so the kernel can
1825  * bind to the controller ... guaranteeing it can handle enumeration
1826  * at all necessary speeds.  Descriptor order is:
1827  *
1828  * . message tag (u32, host order) ... for now, must be zero; it
1829  *      would change to support features like multi-config devices
1830  * . full/low speed config ... all wTotalLength bytes (with interface,
1831  *      class, altsetting, endpoint, and other descriptors)
1832  * . high speed config ... all descriptors, for high speed operation;
1833  *      this one's optional except for high-speed hardware
1834  * . device descriptor
1835  *
1836  * Endpoints are not yet enabled. Drivers must wait until device
1837  * configuration and interface altsetting changes create
1838  * the need to configure (or unconfigure) them.
1839  *
1840  * After initialization, the device stays active for as long as that
1841  * $CHIP file is open.  Events must then be read from that descriptor,
1842  * such as configuration notifications.
1843  */
1844
1845 static int is_valid_config(struct usb_config_descriptor *config,
1846                 unsigned int total)
1847 {
1848         return config->bDescriptorType == USB_DT_CONFIG
1849                 && config->bLength == USB_DT_CONFIG_SIZE
1850                 && total >= USB_DT_CONFIG_SIZE
1851                 && config->bConfigurationValue != 0
1852                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1853                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1854         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1855         /* FIXME check lengths: walk to end */
1856 }
1857
1858 static ssize_t
1859 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1860 {
1861         struct dev_data         *dev = fd->private_data;
1862         ssize_t                 value = len, length = len;
1863         unsigned                total;
1864         u32                     tag;
1865         char                    *kbuf;
1866
1867         if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1868             (len > PAGE_SIZE * 4))
1869                 return -EINVAL;
1870
1871         /* we might need to change message format someday */
1872         if (copy_from_user (&tag, buf, 4))
1873                 return -EFAULT;
1874         if (tag != 0)
1875                 return -EINVAL;
1876         buf += 4;
1877         length -= 4;
1878
1879         kbuf = memdup_user(buf, length);
1880         if (IS_ERR(kbuf))
1881                 return PTR_ERR(kbuf);
1882
1883         spin_lock_irq (&dev->lock);
1884         value = -EINVAL;
1885         if (dev->buf)
1886                 goto fail;
1887         dev->buf = kbuf;
1888
1889         /* full or low speed config */
1890         dev->config = (void *) kbuf;
1891         total = le16_to_cpu(dev->config->wTotalLength);
1892         if (!is_valid_config(dev->config, total) ||
1893                         total > length - USB_DT_DEVICE_SIZE)
1894                 goto fail;
1895         kbuf += total;
1896         length -= total;
1897
1898         /* optional high speed config */
1899         if (kbuf [1] == USB_DT_CONFIG) {
1900                 dev->hs_config = (void *) kbuf;
1901                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1902                 if (!is_valid_config(dev->hs_config, total) ||
1903                                 total > length - USB_DT_DEVICE_SIZE)
1904                         goto fail;
1905                 kbuf += total;
1906                 length -= total;
1907         } else {
1908                 dev->hs_config = NULL;
1909         }
1910
1911         /* could support multiple configs, using another encoding! */
1912
1913         /* device descriptor (tweaked for paranoia) */
1914         if (length != USB_DT_DEVICE_SIZE)
1915                 goto fail;
1916         dev->dev = (void *)kbuf;
1917         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1918                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1919                         || dev->dev->bNumConfigurations != 1)
1920                 goto fail;
1921         dev->dev->bNumConfigurations = 1;
1922         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1923
1924         /* triggers gadgetfs_bind(); then we can enumerate. */
1925         spin_unlock_irq (&dev->lock);
1926         value = usb_gadget_probe_driver(&gadgetfs_driver, gadgetfs_bind);
1927         if (value != 0) {
1928                 kfree (dev->buf);
1929                 dev->buf = NULL;
1930         } else {
1931                 /* at this point "good" hardware has for the first time
1932                  * let the USB the host see us.  alternatively, if users
1933                  * unplug/replug that will clear all the error state.
1934                  *
1935                  * note:  everything running before here was guaranteed
1936                  * to choke driver model style diagnostics.  from here
1937                  * on, they can work ... except in cleanup paths that
1938                  * kick in after the ep0 descriptor is closed.
1939                  */
1940                 fd->f_op = &ep0_io_operations;
1941                 value = len;
1942         }
1943         return value;
1944
1945 fail:
1946         spin_unlock_irq (&dev->lock);
1947         pr_debug ("%s: %s fail %Zd, %p\n", shortname, __func__, value, dev);
1948         kfree (dev->buf);
1949         dev->buf = NULL;
1950         return value;
1951 }
1952
1953 static int
1954 dev_open (struct inode *inode, struct file *fd)
1955 {
1956         struct dev_data         *dev = inode->i_private;
1957         int                     value = -EBUSY;
1958
1959         spin_lock_irq(&dev->lock);
1960         if (dev->state == STATE_DEV_DISABLED) {
1961                 dev->ev_next = 0;
1962                 dev->state = STATE_DEV_OPENED;
1963                 fd->private_data = dev;
1964                 get_dev (dev);
1965                 value = 0;
1966         }
1967         spin_unlock_irq(&dev->lock);
1968         return value;
1969 }
1970
1971 static const struct file_operations dev_init_operations = {
1972         .owner =        THIS_MODULE,
1973         .llseek =       no_llseek,
1974
1975         .open =         dev_open,
1976         .write =        dev_config,
1977         .fasync =       ep0_fasync,
1978         .unlocked_ioctl = dev_ioctl,
1979         .release =      dev_release,
1980 };
1981
1982 /*----------------------------------------------------------------------*/
1983
1984 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1985  *
1986  * Mounting the filesystem creates a controller file, used first for
1987  * device configuration then later for event monitoring.
1988  */
1989
1990
1991 /* FIXME PAM etc could set this security policy without mount options
1992  * if epfiles inherited ownership and permissons from ep0 ...
1993  */
1994
1995 static unsigned default_uid;
1996 static unsigned default_gid;
1997 static unsigned default_perm = S_IRUSR | S_IWUSR;
1998
1999 module_param (default_uid, uint, 0644);
2000 module_param (default_gid, uint, 0644);
2001 module_param (default_perm, uint, 0644);
2002
2003
2004 static struct inode *
2005 gadgetfs_make_inode (struct super_block *sb,
2006                 void *data, const struct file_operations *fops,
2007                 int mode)
2008 {
2009         struct inode *inode = new_inode (sb);
2010
2011         if (inode) {
2012                 inode->i_ino = get_next_ino();
2013                 inode->i_mode = mode;
2014                 inode->i_uid = default_uid;
2015                 inode->i_gid = default_gid;
2016                 inode->i_atime = inode->i_mtime = inode->i_ctime
2017                                 = CURRENT_TIME;
2018                 inode->i_private = data;
2019                 inode->i_fop = fops;
2020         }
2021         return inode;
2022 }
2023
2024 /* creates in fs root directory, so non-renamable and non-linkable.
2025  * so inode and dentry are paired, until device reconfig.
2026  */
2027 static struct inode *
2028 gadgetfs_create_file (struct super_block *sb, char const *name,
2029                 void *data, const struct file_operations *fops,
2030                 struct dentry **dentry_p)
2031 {
2032         struct dentry   *dentry;
2033         struct inode    *inode;
2034
2035         dentry = d_alloc_name(sb->s_root, name);
2036         if (!dentry)
2037                 return NULL;
2038
2039         inode = gadgetfs_make_inode (sb, data, fops,
2040                         S_IFREG | (default_perm & S_IRWXUGO));
2041         if (!inode) {
2042                 dput(dentry);
2043                 return NULL;
2044         }
2045         d_add (dentry, inode);
2046         *dentry_p = dentry;
2047         return inode;
2048 }
2049
2050 static const struct super_operations gadget_fs_operations = {
2051         .statfs =       simple_statfs,
2052         .drop_inode =   generic_delete_inode,
2053 };
2054
2055 static int
2056 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
2057 {
2058         struct inode    *inode;
2059         struct dentry   *d;
2060         struct dev_data *dev;
2061
2062         if (the_device)
2063                 return -ESRCH;
2064
2065         /* fake probe to determine $CHIP */
2066         (void) usb_gadget_probe_driver(&probe_driver, gadgetfs_probe);
2067         if (!CHIP)
2068                 return -ENODEV;
2069
2070         /* superblock */
2071         sb->s_blocksize = PAGE_CACHE_SIZE;
2072         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2073         sb->s_magic = GADGETFS_MAGIC;
2074         sb->s_op = &gadget_fs_operations;
2075         sb->s_time_gran = 1;
2076
2077         /* root inode */
2078         inode = gadgetfs_make_inode (sb,
2079                         NULL, &simple_dir_operations,
2080                         S_IFDIR | S_IRUGO | S_IXUGO);
2081         if (!inode)
2082                 goto enomem0;
2083         inode->i_op = &simple_dir_inode_operations;
2084         if (!(d = d_alloc_root (inode)))
2085                 goto enomem1;
2086         sb->s_root = d;
2087
2088         /* the ep0 file is named after the controller we expect;
2089          * user mode code can use it for sanity checks, like we do.
2090          */
2091         dev = dev_new ();
2092         if (!dev)
2093                 goto enomem2;
2094
2095         dev->sb = sb;
2096         if (!gadgetfs_create_file (sb, CHIP,
2097                                 dev, &dev_init_operations,
2098                                 &dev->dentry))
2099                 goto enomem3;
2100
2101         /* other endpoint files are available after hardware setup,
2102          * from binding to a controller.
2103          */
2104         the_device = dev;
2105         return 0;
2106
2107 enomem3:
2108         put_dev (dev);
2109 enomem2:
2110         dput (d);
2111 enomem1:
2112         iput (inode);
2113 enomem0:
2114         return -ENOMEM;
2115 }
2116
2117 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2118 static struct dentry *
2119 gadgetfs_mount (struct file_system_type *t, int flags,
2120                 const char *path, void *opts)
2121 {
2122         return mount_single (t, flags, opts, gadgetfs_fill_super);
2123 }
2124
2125 static void
2126 gadgetfs_kill_sb (struct super_block *sb)
2127 {
2128         kill_litter_super (sb);
2129         if (the_device) {
2130                 put_dev (the_device);
2131                 the_device = NULL;
2132         }
2133 }
2134
2135 /*----------------------------------------------------------------------*/
2136
2137 static struct file_system_type gadgetfs_type = {
2138         .owner          = THIS_MODULE,
2139         .name           = shortname,
2140         .mount          = gadgetfs_mount,
2141         .kill_sb        = gadgetfs_kill_sb,
2142 };
2143
2144 /*----------------------------------------------------------------------*/
2145
2146 static int __init init (void)
2147 {
2148         int status;
2149
2150         status = register_filesystem (&gadgetfs_type);
2151         if (status == 0)
2152                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2153                         shortname, driver_desc);
2154         return status;
2155 }
2156 module_init (init);
2157
2158 static void __exit cleanup (void)
2159 {
2160         pr_debug ("unregister %s\n", shortname);
2161         unregister_filesystem (&gadgetfs_type);
2162 }
2163 module_exit (cleanup);
2164