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         if (likely(epdata && epdata->ep && priv->req))
 537                 value = usb_ep_dequeue (epdata->ep, priv->req);
 538         else
 539                 value = -EINVAL;
 540         // spin_unlock(&epdata->dev->lock);
 541         local_irq_enable();
 542
 543         aio_put_req(iocb);
 544         return value;
 545 }
 546
 547 static ssize_t ep_copy_to_user(struct kiocb_priv *priv)
 548 {
 549         ssize_t                 len, total;
 550         void                    *to_copy;
 551         int                     i;
 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
 573         return len;
 574 }
 575
 576 static void ep_user_copy_worker(struct work_struct *work)
 577 {
 578         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 579         struct mm_struct *mm = priv->mm;
 580         struct kiocb *iocb = priv->iocb;
 581         size_t ret;
 582
 583         use_mm(mm);
 584         ret = ep_copy_to_user(priv);
 585         unuse_mm(mm);
 586
 587         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 588         aio_complete(iocb, ret, ret);
 589
 590         kfree(priv->buf);
 591         kfree(priv);
 592 }
 593
 594 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 595 {
 596         struct kiocb            *iocb = req->context;
 597         struct kiocb_priv       *priv = iocb->private;
 598         struct ep_data          *epdata = priv->epdata;
 599
 600         /* lock against disconnect (and ideally, cancel) */
 601         spin_lock(&epdata->dev->lock);
 602         priv->req = NULL;
 603         priv->epdata = NULL;
 604
 605         /* if this was a write or a read returning no data then we
 606          * don't need to copy anything to userspace, so we can
 607          * complete the aio request immediately.
 608          */
 609         if (priv->iv == NULL || unlikely(req->actual == 0)) {
 610                 kfree(req->buf);
 611                 kfree(priv);
 612                 iocb->private = NULL;
 613                 /* aio_complete() reports bytes-transferred _and_ faults */
 614                 aio_complete(iocb, req->actual ? req->actual : req->status,
 615                                 req->status);
 616         } else {
 617                 /* ep_copy_to_user() won't report both; we hide some faults */
 618                 if (unlikely(0 != req->status))
 619                         DBG(epdata->dev, "%s fault %d len %d\n",
 620                                 ep->name, req->status, req->actual);
 621
 622                 priv->buf = req->buf;
 623                 priv->actual = req->actual;
 624                 schedule_work(&priv->work);
 625         }
 626         spin_unlock(&epdata->dev->lock);
 627
 628         usb_ep_free_request(ep, req);
 629         put_ep(epdata);
 630 }
 631
 632 static ssize_t
 633 ep_aio_rwtail(
 634         struct kiocb    *iocb,
 635         char            *buf,
 636         size_t          len,
 637         struct ep_data  *epdata,
 638         const struct iovec *iv,
 639         unsigned long   nr_segs
 640 )
 641 {
 642         struct kiocb_priv       *priv;
 643         struct usb_request      *req;
 644         ssize_t                 value;
 645
 646         priv = kmalloc(sizeof *priv, GFP_KERNEL);
 647         if (!priv) {
 648                 value = -ENOMEM;
 649 fail:
 650                 kfree(buf);
 651                 return value;
 652         }
 653         iocb->private = priv;
 654         priv->iocb = iocb;
 655         priv->iv = iv;
 656         priv->nr_segs = nr_segs;
 657         INIT_WORK(&priv->work, ep_user_copy_worker);
 658
 659         value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
 660         if (unlikely(value < 0)) {
 661                 kfree(priv);
 662                 goto fail;
 663         }
 664
 665         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 666         get_ep(epdata);
 667         priv->epdata = epdata;
 668         priv->actual = 0;
 669         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 670
 671         /* each kiocb is coupled to one usb_request, but we can't
 672          * allocate or submit those if the host disconnected.
 673          */
 674         spin_lock_irq(&epdata->dev->lock);
 675         if (likely(epdata->ep)) {
 676                 req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 677                 if (likely(req)) {
 678                         priv->req = req;
 679                         req->buf = buf;
 680                         req->length = len;
 681                         req->complete = ep_aio_complete;
 682                         req->context = iocb;
 683                         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 684                         if (unlikely(0 != value))
 685                                 usb_ep_free_request(epdata->ep, req);
 686                 } else
 687                         value = -EAGAIN;
 688         } else
 689                 value = -ENODEV;
 690         spin_unlock_irq(&epdata->dev->lock);
 691
 692         mutex_unlock(&epdata->lock);
 693
 694         if (unlikely(value)) {
 695                 kfree(priv);
 696                 put_ep(epdata);
 697         } else
 698                 value = -EIOCBQUEUED;
 699         return value;
 700 }
 701
 702 static ssize_t
 703 ep_aio_read(struct kiocb *iocb, const struct iovec *iov,
 704                 unsigned long nr_segs, loff_t o)
 705 {
 706         struct ep_data          *epdata = iocb->ki_filp->private_data;
 707         char                    *buf;
 708
 709         if (unlikely(usb_endpoint_dir_in(&epdata->desc)))
 710                 return -EINVAL;
 711
 712         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 713         if (unlikely(!buf))
 714                 return -ENOMEM;
 715
 716         return ep_aio_rwtail(iocb, buf, iocb->ki_left, epdata, iov, nr_segs);
 717 }
 718
 719 static ssize_t
 720 ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
 721                 unsigned long nr_segs, loff_t o)
 722 {
 723         struct ep_data          *epdata = iocb->ki_filp->private_data;
 724         char                    *buf;
 725         size_t                  len = 0;
 726         int                     i = 0;
 727
 728         if (unlikely(!usb_endpoint_dir_in(&epdata->desc)))
 729                 return -EINVAL;
 730
 731         buf = kmalloc(iocb->ki_left, GFP_KERNEL);
 732         if (unlikely(!buf))
 733                 return -ENOMEM;
 734
 735         for (i=0; i < nr_segs; i++) {
 736                 if (unlikely(copy_from_user(&buf[len], iov[i].iov_base,
 737                                 iov[i].iov_len) != 0)) {
 738                         kfree(buf);
 739                         return -EFAULT;
 740                 }
 741                 len += iov[i].iov_len;
 742         }
 743         return ep_aio_rwtail(iocb, buf, len, epdata, NULL, 0);
 744 }
 745
 746 /*----------------------------------------------------------------------*/
 747
 748 /* used after endpoint configuration */
 749 static const struct file_operations ep_io_operations = {
 750         .owner =        THIS_MODULE,
 751         .llseek =       no_llseek,
 752
 753         .read =         ep_read,
 754         .write =        ep_write,
 755         .unlocked_ioctl = ep_ioctl,
 756         .release =      ep_release,
 757
 758         .aio_read =     ep_aio_read,
 759         .aio_write =    ep_aio_write,
 760 };
 761
 762 /* ENDPOINT INITIALIZATION
 763  *
 764  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 765  *     status = write (fd, descriptors, sizeof descriptors)
 766  *
 767  * That write establishes the endpoint configuration, configuring
 768  * the controller to process bulk, interrupt, or isochronous transfers
 769  * at the right maxpacket size, and so on.
 770  *
 771  * The descriptors are message type 1, identified by a host order u32
 772  * at the beginning of what's written.  Descriptor order is: full/low
 773  * speed descriptor, then optional high speed descriptor.
 774  */
 775 static ssize_t
 776 ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 777 {
 778         struct ep_data          *data = fd->private_data;
 779         struct usb_ep           *ep;
 780         u32                     tag;
 781         int                     value, length = len;
 782
 783         value = mutex_lock_interruptible(&data->lock);
 784         if (value < 0)
 785                 return value;
 786
 787         if (data->state != STATE_EP_READY) {
 788                 value = -EL2HLT;
 789                 goto fail;
 790         }
 791
 792         value = len;
 793         if (len < USB_DT_ENDPOINT_SIZE + 4)
 794                 goto fail0;
 795
 796         /* we might need to change message format someday */
 797         if (copy_from_user (&tag, buf, 4)) {
 798                 goto fail1;
 799         }
 800         if (tag != 1) {
 801                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 802                 goto fail0;
 803         }
 804         buf += 4;
 805         len -= 4;
 806
 807         /* NOTE:  audio endpoint extensions not accepted here;
 808          * just don't include the extra bytes.
 809          */
 810
 811         /* full/low speed descriptor, then high speed */
 812         if (copy_from_user (&data->desc, buf, USB_DT_ENDPOINT_SIZE)) {
 813                 goto fail1;
 814         }
 815         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 816                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 817                 goto fail0;
 818         if (len != USB_DT_ENDPOINT_SIZE) {
 819                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 820                         goto fail0;
 821                 if (copy_from_user (&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 822                                         USB_DT_ENDPOINT_SIZE)) {
 823                         goto fail1;
 824                 }
 825                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 826                                 || data->hs_desc.bDescriptorType
 827                                         != USB_DT_ENDPOINT) {
 828                         DBG(data->dev, "config %s, bad hs length or type\n",
 829                                         data->name);
 830                         goto fail0;
 831                 }
 832         }
 833
 834         spin_lock_irq (&data->dev->lock);
 835         if (data->dev->state == STATE_DEV_UNBOUND) {
 836                 value = -ENOENT;
 837                 goto gone;
 838         } else if ((ep = data->ep) == NULL) {
 839                 value = -ENODEV;
 840                 goto gone;
 841         }
 842         switch (data->dev->gadget->speed) {
 843         case USB_SPEED_LOW:
 844         case USB_SPEED_FULL:
 845                 ep->desc = &data->desc;
 846                 value = usb_ep_enable(ep);
 847                 if (value == 0)
 848                         data->state = STATE_EP_ENABLED;
 849                 break;
 850         case USB_SPEED_HIGH:
 851                 /* fails if caller didn't provide that descriptor... */
 852                 ep->desc = &data->hs_desc;
 853                 value = usb_ep_enable(ep);
 854                 if (value == 0)
 855                         data->state = STATE_EP_ENABLED;
 856                 break;
 857         default:
 858                 DBG(data->dev, "unconnected, %s init abandoned\n",
 859                                 data->name);
 860                 value = -EINVAL;
 861         }
 862         if (value == 0) {
 863                 fd->f_op = &ep_io_operations;
 864                 value = length;
 865         }
 866 gone:
 867         spin_unlock_irq (&data->dev->lock);
 868         if (value < 0) {
 869 fail:
 870                 data->desc.bDescriptorType = 0;
 871                 data->hs_desc.bDescriptorType = 0;
 872         }
 873         mutex_unlock(&data->lock);
 874         return value;
 875 fail0:
 876         value = -EINVAL;
 877         goto fail;
 878 fail1:
 879         value = -EFAULT;
 880         goto fail;
 881 }
 882
 883 static int
 884 ep_open (struct inode *inode, struct file *fd)
 885 {
 886         struct ep_data          *data = inode->i_private;
 887         int                     value = -EBUSY;
 888
 889         if (mutex_lock_interruptible(&data->lock) != 0)
 890                 return -EINTR;
 891         spin_lock_irq (&data->dev->lock);
 892         if (data->dev->state == STATE_DEV_UNBOUND)
 893                 value = -ENOENT;
 894         else if (data->state == STATE_EP_DISABLED) {
 895                 value = 0;
 896                 data->state = STATE_EP_READY;
 897                 get_ep (data);
 898                 fd->private_data = data;
 899                 VDEBUG (data->dev, "%s ready\n", data->name);
 900         } else
 901                 DBG (data->dev, "%s state %d\n",
 902                         data->name, data->state);
 903         spin_unlock_irq (&data->dev->lock);
 904         mutex_unlock(&data->lock);
 905         return value;
 906 }
 907
 908 /* used before endpoint configuration */
 909 static const struct file_operations ep_config_operations = {
 910         .llseek =       no_llseek,
 911
 912         .open =         ep_open,
 913         .write =        ep_config,
 914         .release =      ep_release,
 915 };
 916
 917 /*----------------------------------------------------------------------*/
 918
 919 /* EP0 IMPLEMENTATION can be partly in userspace.
 920  *
 921  * Drivers that use this facility receive various events, including
 922  * control requests the kernel doesn't handle.  Drivers that don't
 923  * use this facility may be too simple-minded for real applications.
 924  */
 925
 926 static inline void ep0_readable (struct dev_data *dev)
 927 {
 928         wake_up (&dev->wait);
 929         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 930 }
 931
 932 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 933 {
 934         struct dev_data         *dev = ep->driver_data;
 935
 936         if (req->buf != dev->rbuf) {
 937                 kfree(req->buf);
 938                 req->buf = dev->rbuf;
 939         }
 940         req->complete = epio_complete;
 941         dev->setup_out_ready = 0;
 942 }
 943
 944 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 945 {
 946         struct dev_data         *dev = ep->driver_data;
 947         unsigned long           flags;
 948         int                     free = 1;
 949
 950         /* for control OUT, data must still get to userspace */
 951         spin_lock_irqsave(&dev->lock, flags);
 952         if (!dev->setup_in) {
 953                 dev->setup_out_error = (req->status != 0);
 954                 if (!dev->setup_out_error)
 955                         free = 0;
 956                 dev->setup_out_ready = 1;
 957                 ep0_readable (dev);
 958         }
 959
 960         /* clean up as appropriate */
 961         if (free && req->buf != &dev->rbuf)
 962                 clean_req (ep, req);
 963         req->complete = epio_complete;
 964         spin_unlock_irqrestore(&dev->lock, flags);
 965 }
 966
 967 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 968 {
 969         struct dev_data *dev = ep->driver_data;
 970
 971         if (dev->setup_out_ready) {
 972                 DBG (dev, "ep0 request busy!\n");
 973                 return -EBUSY;
 974         }
 975         if (len > sizeof (dev->rbuf))
 976                 req->buf = kmalloc(len, GFP_ATOMIC);
 977         if (req->buf == NULL) {
 978                 req->buf = dev->rbuf;
 979                 return -ENOMEM;
 980         }
 981         req->complete = ep0_complete;
 982         req->length = len;
 983         req->zero = 0;
 984         return 0;
 985 }
 986
 987 static ssize_t
 988 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 989 {
 990         struct dev_data                 *dev = fd->private_data;
 991         ssize_t                         retval;
 992         enum ep0_state                  state;
 993
 994         spin_lock_irq (&dev->lock);
 995
 996         /* report fd mode change before acting on it */
 997         if (dev->setup_abort) {
 998                 dev->setup_abort = 0;
 999                 retval = -EIDRM;
1000                 goto done;
1001         }
1002
1003         /* control DATA stage */
1004         if ((state = dev->state) == STATE_DEV_SETUP) {
1005
1006                 if (dev->setup_in) {            /* stall IN */
1007                         VDEBUG(dev, "ep0in stall\n");
1008                         (void) usb_ep_set_halt (dev->gadget->ep0);
1009                         retval = -EL2HLT;
1010                         dev->state = STATE_DEV_CONNECTED;
1011
1012                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
1013                         struct usb_ep           *ep = dev->gadget->ep0;
1014                         struct usb_request      *req = dev->req;
1015
1016                         if ((retval = setup_req (ep, req, 0)) == 0)
1017                                 retval = usb_ep_queue (ep, req, GFP_ATOMIC);
1018                         dev->state = STATE_DEV_CONNECTED;
1019
1020                         /* assume that was SET_CONFIGURATION */
1021                         if (dev->current_config) {
1022                                 unsigned power;
1023
1024                                 if (gadget_is_dualspeed(dev->gadget)
1025                                                 && (dev->gadget->speed
1026                                                         == USB_SPEED_HIGH))
1027                                         power = dev->hs_config->bMaxPower;
1028                                 else
1029                                         power = dev->config->bMaxPower;
1030                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
1031                         }
1032
1033                 } else {                        /* collect OUT data */
1034                         if ((fd->f_flags & O_NONBLOCK) != 0
1035                                         && !dev->setup_out_ready) {
1036                                 retval = -EAGAIN;
1037                                 goto done;
1038                         }
1039                         spin_unlock_irq (&dev->lock);
1040                         retval = wait_event_interruptible (dev->wait,
1041                                         dev->setup_out_ready != 0);
1042
1043                         /* FIXME state could change from under us */
1044                         spin_lock_irq (&dev->lock);
1045                         if (retval)
1046                                 goto done;
1047
1048                         if (dev->state != STATE_DEV_SETUP) {
1049                                 retval = -ECANCELED;
1050                                 goto done;
1051                         }
1052                         dev->state = STATE_DEV_CONNECTED;
1053
1054                         if (dev->setup_out_error)
1055                                 retval = -EIO;
1056                         else {
1057                                 len = min (len, (size_t)dev->req->actual);
1058 // FIXME don't call this with the spinlock held ...
1059                                 if (copy_to_user (buf, dev->req->buf, len))
1060                                         retval = -EFAULT;
1061                                 else
1062                                         retval = len;
1063                                 clean_req (dev->gadget->ep0, dev->req);
1064                                 /* NOTE userspace can't yet choose to stall */
1065                         }
1066                 }
1067                 goto done;
1068         }
1069
1070         /* else normal: return event data */
1071         if (len < sizeof dev->event [0]) {
1072                 retval = -EINVAL;
1073                 goto done;
1074         }
1075         len -= len % sizeof (struct usb_gadgetfs_event);
1076         dev->usermode_setup = 1;
1077
1078 scan:
1079         /* return queued events right away */
1080         if (dev->ev_next != 0) {
1081                 unsigned                i, n;
1082
1083                 n = len / sizeof (struct usb_gadgetfs_event);
1084                 if (dev->ev_next < n)
1085                         n = dev->ev_next;
1086
1087                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1088                 for (i = 0; i < n; i++) {
1089                         if (dev->event [i].type == GADGETFS_SETUP) {
1090                                 dev->state = STATE_DEV_SETUP;
1091                                 n = i + 1;
1092                                 break;
1093                         }
1094                 }
1095                 spin_unlock_irq (&dev->lock);
1096                 len = n * sizeof (struct usb_gadgetfs_event);
1097                 if (copy_to_user (buf, &dev->event, len))
1098                         retval = -EFAULT;
1099                 else
1100                         retval = len;
1101                 if (len > 0) {
1102                         /* NOTE this doesn't guard against broken drivers;
1103                          * concurrent ep0 readers may lose events.
1104                          */
1105                         spin_lock_irq (&dev->lock);
1106                         if (dev->ev_next > n) {
1107                                 memmove(&dev->event[0], &dev->event[n],
1108                                         sizeof (struct usb_gadgetfs_event)
1109                                                 * (dev->ev_next - n));
1110                         }
1111                         dev->ev_next -= n;
1112                         spin_unlock_irq (&dev->lock);
1113                 }
1114                 return retval;
1115         }
1116         if (fd->f_flags & O_NONBLOCK) {
1117                 retval = -EAGAIN;
1118                 goto done;
1119         }
1120
1121         switch (state) {
1122         default:
1123                 DBG (dev, "fail %s, state %d\n", __func__, state);
1124                 retval = -ESRCH;
1125                 break;
1126         case STATE_DEV_UNCONNECTED:
1127         case STATE_DEV_CONNECTED:
1128                 spin_unlock_irq (&dev->lock);
1129                 DBG (dev, "%s wait\n", __func__);
1130
1131                 /* wait for events */
1132                 retval = wait_event_interruptible (dev->wait,
1133                                 dev->ev_next != 0);
1134                 if (retval < 0)
1135                         return retval;
1136                 spin_lock_irq (&dev->lock);
1137                 goto scan;
1138         }
1139
1140 done:
1141         spin_unlock_irq (&dev->lock);
1142         return retval;
1143 }
1144
1145 static struct usb_gadgetfs_event *
1146 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1147 {
1148         struct usb_gadgetfs_event       *event;
1149         unsigned                        i;
1150
1151         switch (type) {
1152         /* these events purge the queue */
1153         case GADGETFS_DISCONNECT:
1154                 if (dev->state == STATE_DEV_SETUP)
1155                         dev->setup_abort = 1;
1156                 // FALL THROUGH
1157         case GADGETFS_CONNECT:
1158                 dev->ev_next = 0;
1159                 break;
1160         case GADGETFS_SETUP:            /* previous request timed out */
1161         case GADGETFS_SUSPEND:          /* same effect */
1162                 /* these events can't be repeated */
1163                 for (i = 0; i != dev->ev_next; i++) {
1164                         if (dev->event [i].type != type)
1165                                 continue;
1166                         DBG(dev, "discard old event[%d] %d\n", i, type);
1167                         dev->ev_next--;
1168                         if (i == dev->ev_next)
1169                                 break;
1170                         /* indices start at zero, for simplicity */
1171                         memmove (&dev->event [i], &dev->event [i + 1],
1172                                 sizeof (struct usb_gadgetfs_event)
1173                                         * (dev->ev_next - i));
1174                 }
1175                 break;
1176         default:
1177                 BUG ();
1178         }
1179         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1180         event = &dev->event [dev->ev_next++];
1181         BUG_ON (dev->ev_next > N_EVENT);
1182         memset (event, 0, sizeof *event);
1183         event->type = type;
1184         return event;
1185 }
1186
1187 static ssize_t
1188 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1189 {
1190         struct dev_data         *dev = fd->private_data;
1191         ssize_t                 retval = -ESRCH;
1192
1193         spin_lock_irq (&dev->lock);
1194
1195         /* report fd mode change before acting on it */
1196         if (dev->setup_abort) {
1197                 dev->setup_abort = 0;
1198                 retval = -EIDRM;
1199
1200         /* data and/or status stage for control request */
1201         } else if (dev->state == STATE_DEV_SETUP) {
1202
1203                 /* IN DATA+STATUS caller makes len <= wLength */
1204                 if (dev->setup_in) {
1205                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1206                         if (retval == 0) {
1207                                 dev->state = STATE_DEV_CONNECTED;
1208                                 spin_unlock_irq (&dev->lock);
1209                                 if (copy_from_user (dev->req->buf, buf, len))
1210                                         retval = -EFAULT;
1211                                 else {
1212                                         if (len < dev->setup_wLength)
1213                                                 dev->req->zero = 1;
1214                                         retval = usb_ep_queue (
1215                                                 dev->gadget->ep0, dev->req,
1216                                                 GFP_KERNEL);
1217                                 }
1218                                 if (retval < 0) {
1219                                         spin_lock_irq (&dev->lock);
1220                                         clean_req (dev->gadget->ep0, dev->req);
1221                                         spin_unlock_irq (&dev->lock);
1222                                 } else
1223                                         retval = len;
1224
1225                                 return retval;
1226                         }
1227
1228                 /* can stall some OUT transfers */
1229                 } else if (dev->setup_can_stall) {
1230                         VDEBUG(dev, "ep0out stall\n");
1231                         (void) usb_ep_set_halt (dev->gadget->ep0);
1232                         retval = -EL2HLT;
1233                         dev->state = STATE_DEV_CONNECTED;
1234                 } else {
1235                         DBG(dev, "bogus ep0out stall!\n");
1236                 }
1237         } else
1238                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1239
1240         spin_unlock_irq (&dev->lock);
1241         return retval;
1242 }
1243
1244 static int
1245 ep0_fasync (int f, struct file *fd, int on)
1246 {
1247         struct dev_data         *dev = fd->private_data;
1248         // caller must F_SETOWN before signal delivery happens
1249         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1250         return fasync_helper (f, fd, on, &dev->fasync);
1251 }
1252
1253 static struct usb_gadget_driver gadgetfs_driver;
1254
1255 static int
1256 dev_release (struct inode *inode, struct file *fd)
1257 {
1258         struct dev_data         *dev = fd->private_data;
1259
1260         /* closing ep0 === shutdown all */
1261
1262         usb_gadget_unregister_driver (&gadgetfs_driver);
1263
1264         /* at this point "good" hardware has disconnected the
1265          * device from USB; the host won't see it any more.
1266          * alternatively, all host requests will time out.
1267          */
1268
1269         kfree (dev->buf);
1270         dev->buf = NULL;
1271         put_dev (dev);
1272
1273         /* other endpoints were all decoupled from this device */
1274         spin_lock_irq(&dev->lock);
1275         dev->state = STATE_DEV_DISABLED;
1276         spin_unlock_irq(&dev->lock);
1277         return 0;
1278 }
1279
1280 static unsigned int
1281 ep0_poll (struct file *fd, poll_table *wait)
1282 {
1283        struct dev_data         *dev = fd->private_data;
1284        int                     mask = 0;
1285
1286        poll_wait(fd, &dev->wait, wait);
1287
1288        spin_lock_irq (&dev->lock);
1289
1290        /* report fd mode change before acting on it */
1291        if (dev->setup_abort) {
1292                dev->setup_abort = 0;
1293                mask = POLLHUP;
1294                goto out;
1295        }
1296
1297        if (dev->state == STATE_DEV_SETUP) {
1298                if (dev->setup_in || dev->setup_can_stall)
1299                        mask = POLLOUT;
1300        } else {
1301                if (dev->ev_next != 0)
1302                        mask = POLLIN;
1303        }
1304 out:
1305        spin_unlock_irq(&dev->lock);
1306        return mask;
1307 }
1308
1309 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1310 {
1311         struct dev_data         *dev = fd->private_data;
1312         struct usb_gadget       *gadget = dev->gadget;
1313         long ret = -ENOTTY;
1314
1315         if (gadget->ops->ioctl)
1316                 ret = gadget->ops->ioctl (gadget, code, value);
1317
1318         return ret;
1319 }
1320
1321 /* used after device configuration */
1322 static const struct file_operations ep0_io_operations = {
1323         .owner =        THIS_MODULE,
1324         .llseek =       no_llseek,
1325
1326         .read =         ep0_read,
1327         .write =        ep0_write,
1328         .fasync =       ep0_fasync,
1329         .poll =         ep0_poll,
1330         .unlocked_ioctl =       dev_ioctl,
1331         .release =      dev_release,
1332 };
1333
1334 /*----------------------------------------------------------------------*/
1335
1336 /* The in-kernel gadget driver handles most ep0 issues, in particular
1337  * enumerating the single configuration (as provided from user space).
1338  *
1339  * Unrecognized ep0 requests may be handled in user space.
1340  */
1341
1342 static void make_qualifier (struct dev_data *dev)
1343 {
1344         struct usb_qualifier_descriptor         qual;
1345         struct usb_device_descriptor            *desc;
1346
1347         qual.bLength = sizeof qual;
1348         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1349         qual.bcdUSB = cpu_to_le16 (0x0200);
1350
1351         desc = dev->dev;
1352         qual.bDeviceClass = desc->bDeviceClass;
1353         qual.bDeviceSubClass = desc->bDeviceSubClass;
1354         qual.bDeviceProtocol = desc->bDeviceProtocol;
1355
1356         /* assumes ep0 uses the same value for both speeds ... */
1357         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1358
1359         qual.bNumConfigurations = 1;
1360         qual.bRESERVED = 0;
1361
1362         memcpy (dev->rbuf, &qual, sizeof qual);
1363 }
1364
1365 static int
1366 config_buf (struct dev_data *dev, u8 type, unsigned index)
1367 {
1368         int             len;
1369         int             hs = 0;
1370
1371         /* only one configuration */
1372         if (index > 0)
1373                 return -EINVAL;
1374
1375         if (gadget_is_dualspeed(dev->gadget)) {
1376                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1377                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1378                         hs = !hs;
1379         }
1380         if (hs) {
1381                 dev->req->buf = dev->hs_config;
1382                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1383         } else {
1384                 dev->req->buf = dev->config;
1385                 len = le16_to_cpu(dev->config->wTotalLength);
1386         }
1387         ((u8 *)dev->req->buf) [1] = type;
1388         return len;
1389 }
1390
1391 static int
1392 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1393 {
1394         struct dev_data                 *dev = get_gadget_data (gadget);
1395         struct usb_request              *req = dev->req;
1396         int                             value = -EOPNOTSUPP;
1397         struct usb_gadgetfs_event       *event;
1398         u16                             w_value = le16_to_cpu(ctrl->wValue);
1399         u16                             w_length = le16_to_cpu(ctrl->wLength);
1400
1401         spin_lock (&dev->lock);
1402         dev->setup_abort = 0;
1403         if (dev->state == STATE_DEV_UNCONNECTED) {
1404                 if (gadget_is_dualspeed(gadget)
1405                                 && gadget->speed == USB_SPEED_HIGH
1406                                 && dev->hs_config == NULL) {
1407                         spin_unlock(&dev->lock);
1408                         ERROR (dev, "no high speed config??\n");
1409                         return -EINVAL;
1410                 }
1411
1412                 dev->state = STATE_DEV_CONNECTED;
1413
1414                 INFO (dev, "connected\n");
1415                 event = next_event (dev, GADGETFS_CONNECT);
1416                 event->u.speed = gadget->speed;
1417                 ep0_readable (dev);
1418
1419         /* host may have given up waiting for response.  we can miss control
1420          * requests handled lower down (device/endpoint status and features);
1421          * then ep0_{read,write} will report the wrong status. controller
1422          * driver will have aborted pending i/o.
1423          */
1424         } else if (dev->state == STATE_DEV_SETUP)
1425                 dev->setup_abort = 1;
1426
1427         req->buf = dev->rbuf;
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                 case USB_DT_DEVICE_QUALIFIER:
1443                         if (!dev->hs_config)
1444                                 break;
1445                         value = min (w_length, (u16)
1446                                 sizeof (struct usb_qualifier_descriptor));
1447                         make_qualifier (dev);
1448                         break;
1449                 case USB_DT_OTHER_SPEED_CONFIG:
1450                         // FALLTHROUGH
1451                 case USB_DT_CONFIG:
1452                         value = config_buf (dev,
1453                                         w_value >> 8,
1454                                         w_value & 0xff);
1455                         if (value >= 0)
1456                                 value = min (w_length, (u16) value);
1457                         break;
1458                 case USB_DT_STRING:
1459                         goto unrecognized;
1460
1461                 default:                // all others are errors
1462                         break;
1463                 }
1464                 break;
1465
1466         /* currently one config, two speeds */
1467         case USB_REQ_SET_CONFIGURATION:
1468                 if (ctrl->bRequestType != 0)
1469                         goto unrecognized;
1470                 if (0 == (u8) w_value) {
1471                         value = 0;
1472                         dev->current_config = 0;
1473                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1474                         // user mode expected to disable endpoints
1475                 } else {
1476                         u8      config, power;
1477
1478                         if (gadget_is_dualspeed(gadget)
1479                                         && gadget->speed == USB_SPEED_HIGH) {
1480                                 config = dev->hs_config->bConfigurationValue;
1481                                 power = dev->hs_config->bMaxPower;
1482                         } else {
1483                                 config = dev->config->bConfigurationValue;
1484                                 power = dev->config->bMaxPower;
1485                         }
1486
1487                         if (config == (u8) w_value) {
1488                                 value = 0;
1489                                 dev->current_config = config;
1490                                 usb_gadget_vbus_draw(gadget, 2 * power);
1491                         }
1492                 }
1493
1494                 /* report SET_CONFIGURATION like any other control request,
1495                  * except that usermode may not stall this.  the next
1496                  * request mustn't be allowed start until this finishes:
1497                  * endpoints and threads set up, etc.
1498                  *
1499                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1500                  * has bad/racey automagic that prevents synchronizing here.
1501                  * even kernel mode drivers often miss them.
1502                  */
1503                 if (value == 0) {
1504                         INFO (dev, "configuration #%d\n", dev->current_config);
1505                         if (dev->usermode_setup) {
1506                                 dev->setup_can_stall = 0;
1507                                 goto delegate;
1508                         }
1509                 }
1510                 break;
1511
1512 #ifndef CONFIG_USB_PXA25X
1513         /* PXA automagically handles this request too */
1514         case USB_REQ_GET_CONFIGURATION:
1515                 if (ctrl->bRequestType != 0x80)
1516                         goto unrecognized;
1517                 *(u8 *)req->buf = dev->current_config;
1518                 value = min (w_length, (u16) 1);
1519                 break;
1520 #endif
1521
1522         default:
1523 unrecognized:
1524                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1525                         dev->usermode_setup ? "delegate" : "fail",
1526                         ctrl->bRequestType, ctrl->bRequest,
1527                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1528
1529                 /* if there's an ep0 reader, don't stall */
1530                 if (dev->usermode_setup) {
1531                         dev->setup_can_stall = 1;
1532 delegate:
1533                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1534                                                 ? 1 : 0;
1535                         dev->setup_wLength = w_length;
1536                         dev->setup_out_ready = 0;
1537                         dev->setup_out_error = 0;
1538                         value = 0;
1539
1540                         /* read DATA stage for OUT right away */
1541                         if (unlikely (!dev->setup_in && w_length)) {
1542                                 value = setup_req (gadget->ep0, dev->req,
1543                                                         w_length);
1544                                 if (value < 0)
1545                                         break;
1546                                 value = usb_ep_queue (gadget->ep0, dev->req,
1547                                                         GFP_ATOMIC);
1548                                 if (value < 0) {
1549                                         clean_req (gadget->ep0, dev->req);
1550                                         break;
1551                                 }
1552
1553                                 /* we can't currently stall these */
1554                                 dev->setup_can_stall = 0;
1555                         }
1556
1557                         /* state changes when reader collects event */
1558                         event = next_event (dev, GADGETFS_SETUP);
1559                         event->u.setup = *ctrl;
1560                         ep0_readable (dev);
1561                         spin_unlock (&dev->lock);
1562                         return 0;
1563                 }
1564         }
1565
1566         /* proceed with data transfer and status phases? */
1567         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1568                 req->length = value;
1569                 req->zero = value < w_length;
1570                 value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
1571                 if (value < 0) {
1572                         DBG (dev, "ep_queue --> %d\n", value);
1573                         req->status = 0;
1574                 }
1575         }
1576
1577         /* device stalls when value < 0 */
1578         spin_unlock (&dev->lock);
1579         return value;
1580 }
1581
1582 static void destroy_ep_files (struct dev_data *dev)
1583 {
1584         DBG (dev, "%s %d\n", __func__, dev->state);
1585
1586         /* dev->state must prevent interference */
1587         spin_lock_irq (&dev->lock);
1588         while (!list_empty(&dev->epfiles)) {
1589                 struct ep_data  *ep;
1590                 struct inode    *parent;
1591                 struct dentry   *dentry;
1592
1593                 /* break link to FS */
1594                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1595                 list_del_init (&ep->epfiles);
1596                 dentry = ep->dentry;
1597                 ep->dentry = NULL;
1598                 parent = dentry->d_parent->d_inode;
1599
1600                 /* break link to controller */
1601                 if (ep->state == STATE_EP_ENABLED)
1602                         (void) usb_ep_disable (ep->ep);
1603                 ep->state = STATE_EP_UNBOUND;
1604                 usb_ep_free_request (ep->ep, ep->req);
1605                 ep->ep = NULL;
1606                 wake_up (&ep->wait);
1607                 put_ep (ep);
1608
1609                 spin_unlock_irq (&dev->lock);
1610
1611                 /* break link to dcache */
1612                 mutex_lock (&parent->i_mutex);
1613                 d_delete (dentry);
1614                 dput (dentry);
1615                 mutex_unlock (&parent->i_mutex);
1616
1617                 spin_lock_irq (&dev->lock);
1618         }
1619         spin_unlock_irq (&dev->lock);
1620 }
1621
1622
1623 static struct inode *
1624 gadgetfs_create_file (struct super_block *sb, char const *name,
1625                 void *data, const struct file_operations *fops,
1626                 struct dentry **dentry_p);
1627
1628 static int activate_ep_files (struct dev_data *dev)
1629 {
1630         struct usb_ep   *ep;
1631         struct ep_data  *data;
1632
1633         gadget_for_each_ep (ep, dev->gadget) {
1634
1635                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1636                 if (!data)
1637                         goto enomem0;
1638                 data->state = STATE_EP_DISABLED;
1639                 mutex_init(&data->lock);
1640                 init_waitqueue_head (&data->wait);
1641
1642                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1643                 atomic_set (&data->count, 1);
1644                 data->dev = dev;
1645                 get_dev (dev);
1646
1647                 data->ep = ep;
1648                 ep->driver_data = data;
1649
1650                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1651                 if (!data->req)
1652                         goto enomem1;
1653
1654                 data->inode = gadgetfs_create_file (dev->sb, data->name,
1655                                 data, &ep_config_operations,
1656                                 &data->dentry);
1657                 if (!data->inode)
1658                         goto enomem2;
1659                 list_add_tail (&data->epfiles, &dev->epfiles);
1660         }
1661         return 0;
1662
1663 enomem2:
1664         usb_ep_free_request (ep, data->req);
1665 enomem1:
1666         put_dev (dev);
1667         kfree (data);
1668 enomem0:
1669         DBG (dev, "%s enomem\n", __func__);
1670         destroy_ep_files (dev);
1671         return -ENOMEM;
1672 }
1673
1674 static void
1675 gadgetfs_unbind (struct usb_gadget *gadget)
1676 {
1677         struct dev_data         *dev = get_gadget_data (gadget);
1678
1679         DBG (dev, "%s\n", __func__);
1680
1681         spin_lock_irq (&dev->lock);
1682         dev->state = STATE_DEV_UNBOUND;
1683         spin_unlock_irq (&dev->lock);
1684
1685         destroy_ep_files (dev);
1686         gadget->ep0->driver_data = NULL;
1687         set_gadget_data (gadget, NULL);
1688
1689         /* we've already been disconnected ... no i/o is active */
1690         if (dev->req)
1691                 usb_ep_free_request (gadget->ep0, dev->req);
1692         DBG (dev, "%s done\n", __func__);
1693         put_dev (dev);
1694 }
1695
1696 static struct dev_data          *the_device;
1697
1698 static int gadgetfs_bind(struct usb_gadget *gadget,
1699                 struct usb_gadget_driver *driver)
1700 {
1701         struct dev_data         *dev = the_device;
1702
1703         if (!dev)
1704                 return -ESRCH;
1705         if (0 != strcmp (CHIP, gadget->name)) {
1706                 pr_err("%s expected %s controller not %s\n",
1707                         shortname, CHIP, gadget->name);
1708                 return -ENODEV;
1709         }
1710
1711         set_gadget_data (gadget, dev);
1712         dev->gadget = gadget;
1713         gadget->ep0->driver_data = dev;
1714
1715         /* preallocate control response and buffer */
1716         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1717         if (!dev->req)
1718                 goto enomem;
1719         dev->req->context = NULL;
1720         dev->req->complete = epio_complete;
1721
1722         if (activate_ep_files (dev) < 0)
1723                 goto enomem;
1724
1725         INFO (dev, "bound to %s driver\n", gadget->name);
1726         spin_lock_irq(&dev->lock);
1727         dev->state = STATE_DEV_UNCONNECTED;
1728         spin_unlock_irq(&dev->lock);
1729         get_dev (dev);
1730         return 0;
1731
1732 enomem:
1733         gadgetfs_unbind (gadget);
1734         return -ENOMEM;
1735 }
1736
1737 static void
1738 gadgetfs_disconnect (struct usb_gadget *gadget)
1739 {
1740         struct dev_data         *dev = get_gadget_data (gadget);
1741         unsigned long           flags;
1742
1743         spin_lock_irqsave (&dev->lock, flags);
1744         if (dev->state == STATE_DEV_UNCONNECTED)
1745                 goto exit;
1746         dev->state = STATE_DEV_UNCONNECTED;
1747
1748         INFO (dev, "disconnected\n");
1749         next_event (dev, GADGETFS_DISCONNECT);
1750         ep0_readable (dev);
1751 exit:
1752         spin_unlock_irqrestore (&dev->lock, flags);
1753 }
1754
1755 static void
1756 gadgetfs_suspend (struct usb_gadget *gadget)
1757 {
1758         struct dev_data         *dev = get_gadget_data (gadget);
1759
1760         INFO (dev, "suspended from state %d\n", dev->state);
1761         spin_lock (&dev->lock);
1762         switch (dev->state) {
1763         case STATE_DEV_SETUP:           // VERY odd... host died??
1764         case STATE_DEV_CONNECTED:
1765         case STATE_DEV_UNCONNECTED:
1766                 next_event (dev, GADGETFS_SUSPEND);
1767                 ep0_readable (dev);
1768                 /* FALLTHROUGH */
1769         default:
1770                 break;
1771         }
1772         spin_unlock (&dev->lock);
1773 }
1774
1775 static struct usb_gadget_driver gadgetfs_driver = {
1776         .function       = (char *) driver_desc,
1777         .bind           = gadgetfs_bind,
1778         .unbind         = gadgetfs_unbind,
1779         .setup          = gadgetfs_setup,
1780         .disconnect     = gadgetfs_disconnect,
1781         .suspend        = gadgetfs_suspend,
1782
1783         .driver = {
1784                 .name           = (char *) shortname,
1785         },
1786 };
1787
1788 /*----------------------------------------------------------------------*/
1789
1790 static void gadgetfs_nop(struct usb_gadget *arg) { }
1791
1792 static int gadgetfs_probe(struct usb_gadget *gadget,
1793                 struct usb_gadget_driver *driver)
1794 {
1795         CHIP = gadget->name;
1796         return -EISNAM;
1797 }
1798
1799 static struct usb_gadget_driver probe_driver = {
1800         .max_speed      = USB_SPEED_HIGH,
1801         .bind           = gadgetfs_probe,
1802         .unbind         = gadgetfs_nop,
1803         .setup          = (void *)gadgetfs_nop,
1804         .disconnect     = gadgetfs_nop,
1805         .driver = {
1806                 .name           = "nop",
1807         },
1808 };
1809
1810
1811 /* DEVICE INITIALIZATION
1812  *
1813  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1814  *     status = write (fd, descriptors, sizeof descriptors)
1815  *
1816  * That write establishes the device configuration, so the kernel can
1817  * bind to the controller ... guaranteeing it can handle enumeration
1818  * at all necessary speeds.  Descriptor order is:
1819  *
1820  * . message tag (u32, host order) ... for now, must be zero; it
1821  *      would change to support features like multi-config devices
1822  * . full/low speed config ... all wTotalLength bytes (with interface,
1823  *      class, altsetting, endpoint, and other descriptors)
1824  * . high speed config ... all descriptors, for high speed operation;
1825  *      this one's optional except for high-speed hardware
1826  * . device descriptor
1827  *
1828  * Endpoints are not yet enabled. Drivers must wait until device
1829  * configuration and interface altsetting changes create
1830  * the need to configure (or unconfigure) them.
1831  *
1832  * After initialization, the device stays active for as long as that
1833  * $CHIP file is open.  Events must then be read from that descriptor,
1834  * such as configuration notifications.
1835  */
1836
1837 static int is_valid_config (struct usb_config_descriptor *config)
1838 {
1839         return config->bDescriptorType == USB_DT_CONFIG
1840                 && config->bLength == USB_DT_CONFIG_SIZE
1841                 && config->bConfigurationValue != 0
1842                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1843                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1844         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1845         /* FIXME check lengths: walk to end */
1846 }
1847
1848 static ssize_t
1849 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1850 {
1851         struct dev_data         *dev = fd->private_data;
1852         ssize_t                 value = len, length = len;
1853         unsigned                total;
1854         u32                     tag;
1855         char                    *kbuf;
1856
1857         if (len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4))
1858                 return -EINVAL;
1859
1860         /* we might need to change message format someday */
1861         if (copy_from_user (&tag, buf, 4))
1862                 return -EFAULT;
1863         if (tag != 0)
1864                 return -EINVAL;
1865         buf += 4;
1866         length -= 4;
1867
1868         kbuf = memdup_user(buf, length);
1869         if (IS_ERR(kbuf))
1870                 return PTR_ERR(kbuf);
1871
1872         spin_lock_irq (&dev->lock);
1873         value = -EINVAL;
1874         if (dev->buf)
1875                 goto fail;
1876         dev->buf = kbuf;
1877
1878         /* full or low speed config */
1879         dev->config = (void *) kbuf;
1880         total = le16_to_cpu(dev->config->wTotalLength);
1881         if (!is_valid_config (dev->config) || total >= length)
1882                 goto fail;
1883         kbuf += total;
1884         length -= total;
1885
1886         /* optional high speed config */
1887         if (kbuf [1] == USB_DT_CONFIG) {
1888                 dev->hs_config = (void *) kbuf;
1889                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1890                 if (!is_valid_config (dev->hs_config) || total >= length)
1891                         goto fail;
1892                 kbuf += total;
1893                 length -= total;
1894         }
1895
1896         /* could support multiple configs, using another encoding! */
1897
1898         /* device descriptor (tweaked for paranoia) */
1899         if (length != USB_DT_DEVICE_SIZE)
1900                 goto fail;
1901         dev->dev = (void *)kbuf;
1902         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1903                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1904                         || dev->dev->bNumConfigurations != 1)
1905                 goto fail;
1906         dev->dev->bNumConfigurations = 1;
1907         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1908
1909         /* triggers gadgetfs_bind(); then we can enumerate. */
1910         spin_unlock_irq (&dev->lock);
1911         if (dev->hs_config)
1912                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1913         else
1914                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1915
1916         value = usb_gadget_probe_driver(&gadgetfs_driver);
1917         if (value != 0) {
1918                 kfree (dev->buf);
1919                 dev->buf = NULL;
1920         } else {
1921                 /* at this point "good" hardware has for the first time
1922                  * let the USB the host see us.  alternatively, if users
1923                  * unplug/replug that will clear all the error state.
1924                  *
1925                  * note:  everything running before here was guaranteed
1926                  * to choke driver model style diagnostics.  from here
1927                  * on, they can work ... except in cleanup paths that
1928                  * kick in after the ep0 descriptor is closed.
1929                  */
1930                 fd->f_op = &ep0_io_operations;
1931                 value = len;
1932         }
1933         return value;
1934
1935 fail:
1936         spin_unlock_irq (&dev->lock);
1937         pr_debug ("%s: %s fail %Zd, %p\n", shortname, __func__, value, dev);
1938         kfree (dev->buf);
1939         dev->buf = NULL;
1940         return value;
1941 }
1942
1943 static int
1944 dev_open (struct inode *inode, struct file *fd)
1945 {
1946         struct dev_data         *dev = inode->i_private;
1947         int                     value = -EBUSY;
1948
1949         spin_lock_irq(&dev->lock);
1950         if (dev->state == STATE_DEV_DISABLED) {
1951                 dev->ev_next = 0;
1952                 dev->state = STATE_DEV_OPENED;
1953                 fd->private_data = dev;
1954                 get_dev (dev);
1955                 value = 0;
1956         }
1957         spin_unlock_irq(&dev->lock);
1958         return value;
1959 }
1960
1961 static const struct file_operations dev_init_operations = {
1962         .llseek =       no_llseek,
1963
1964         .open =         dev_open,
1965         .write =        dev_config,
1966         .fasync =       ep0_fasync,
1967         .unlocked_ioctl = dev_ioctl,
1968         .release =      dev_release,
1969 };
1970
1971 /*----------------------------------------------------------------------*/
1972
1973 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1974  *
1975  * Mounting the filesystem creates a controller file, used first for
1976  * device configuration then later for event monitoring.
1977  */
1978
1979
1980 /* FIXME PAM etc could set this security policy without mount options
1981  * if epfiles inherited ownership and permissons from ep0 ...
1982  */
1983
1984 static unsigned default_uid;
1985 static unsigned default_gid;
1986 static unsigned default_perm = S_IRUSR | S_IWUSR;
1987
1988 module_param (default_uid, uint, 0644);
1989 module_param (default_gid, uint, 0644);
1990 module_param (default_perm, uint, 0644);
1991
1992
1993 static struct inode *
1994 gadgetfs_make_inode (struct super_block *sb,
1995                 void *data, const struct file_operations *fops,
1996                 int mode)
1997 {
1998         struct inode *inode = new_inode (sb);
1999
2000         if (inode) {
2001                 inode->i_ino = get_next_ino();
2002                 inode->i_mode = mode;
2003                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
2004                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
2005                 inode->i_atime = inode->i_mtime = inode->i_ctime
2006                                 = CURRENT_TIME;
2007                 inode->i_private = data;
2008                 inode->i_fop = fops;
2009         }
2010         return inode;
2011 }
2012
2013 /* creates in fs root directory, so non-renamable and non-linkable.
2014  * so inode and dentry are paired, until device reconfig.
2015  */
2016 static struct inode *
2017 gadgetfs_create_file (struct super_block *sb, char const *name,
2018                 void *data, const struct file_operations *fops,
2019                 struct dentry **dentry_p)
2020 {
2021         struct dentry   *dentry;
2022         struct inode    *inode;
2023
2024         dentry = d_alloc_name(sb->s_root, name);
2025         if (!dentry)
2026                 return NULL;
2027
2028         inode = gadgetfs_make_inode (sb, data, fops,
2029                         S_IFREG | (default_perm & S_IRWXUGO));
2030         if (!inode) {
2031                 dput(dentry);
2032                 return NULL;
2033         }
2034         d_add (dentry, inode);
2035         *dentry_p = dentry;
2036         return inode;
2037 }
2038
2039 static const struct super_operations gadget_fs_operations = {
2040         .statfs =       simple_statfs,
2041         .drop_inode =   generic_delete_inode,
2042 };
2043
2044 static int
2045 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
2046 {
2047         struct inode    *inode;
2048         struct dev_data *dev;
2049
2050         if (the_device)
2051                 return -ESRCH;
2052
2053         /* fake probe to determine $CHIP */
2054         usb_gadget_probe_driver(&probe_driver);
2055         if (!CHIP)
2056                 return -ENODEV;
2057
2058         /* superblock */
2059         sb->s_blocksize = PAGE_CACHE_SIZE;
2060         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2061         sb->s_magic = GADGETFS_MAGIC;
2062         sb->s_op = &gadget_fs_operations;
2063         sb->s_time_gran = 1;
2064
2065         /* root inode */
2066         inode = gadgetfs_make_inode (sb,
2067                         NULL, &simple_dir_operations,
2068                         S_IFDIR | S_IRUGO | S_IXUGO);
2069         if (!inode)
2070                 goto Enomem;
2071         inode->i_op = &simple_dir_inode_operations;
2072         if (!(sb->s_root = d_make_root (inode)))
2073                 goto Enomem;
2074
2075         /* the ep0 file is named after the controller we expect;
2076          * user mode code can use it for sanity checks, like we do.
2077          */
2078         dev = dev_new ();
2079         if (!dev)
2080                 goto Enomem;
2081
2082         dev->sb = sb;
2083         if (!gadgetfs_create_file (sb, CHIP,
2084                                 dev, &dev_init_operations,
2085                                 &dev->dentry)) {
2086                 put_dev(dev);
2087                 goto Enomem;
2088         }
2089
2090         /* other endpoint files are available after hardware setup,
2091          * from binding to a controller.
2092          */
2093         the_device = dev;
2094         return 0;
2095
2096 Enomem:
2097         return -ENOMEM;
2098 }
2099
2100 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2101 static struct dentry *
2102 gadgetfs_mount (struct file_system_type *t, int flags,
2103                 const char *path, void *opts)
2104 {
2105         return mount_single (t, flags, opts, gadgetfs_fill_super);
2106 }
2107
2108 static void
2109 gadgetfs_kill_sb (struct super_block *sb)
2110 {
2111         kill_litter_super (sb);
2112         if (the_device) {
2113                 put_dev (the_device);
2114                 the_device = NULL;
2115         }
2116 }
2117
2118 /*----------------------------------------------------------------------*/
2119
2120 static struct file_system_type gadgetfs_type = {
2121         .owner          = THIS_MODULE,
2122         .name           = shortname,
2123         .mount          = gadgetfs_mount,
2124         .kill_sb        = gadgetfs_kill_sb,
2125 };
2126 MODULE_ALIAS_FS("gadgetfs");
2127
2128 /*----------------------------------------------------------------------*/
2129
2130 static int __init init (void)
2131 {
2132         int status;
2133
2134         status = register_filesystem (&gadgetfs_type);
2135         if (status == 0)
2136                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2137                         shortname, driver_desc);
2138         return status;
2139 }
2140 module_init (init);
2141
2142 static void __exit cleanup (void)
2143 {
2144         pr_debug ("unregister %s\n", shortname);
2145         unregister_filesystem (&gadgetfs_type);
2146 }
2147 module_exit (cleanup);
2148