drivers/usb/gadget/legacy/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 #include <linux/uio.h>
  30 #include <linux/delay.h>
  31 #include <linux/device.h>
  32 #include <linux/moduleparam.h>
  33
  34 #include <linux/usb/gadgetfs.h>
  35 #include <linux/usb/gadget.h>
  36
  37
  38 /*
  39  * The gadgetfs API maps each endpoint to a file descriptor so that you
  40  * can use standard synchronous read/write calls for I/O.  There's some
  41  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  42  * drivers show how this works in practice.  You can also use AIO to
  43  * eliminate I/O gaps between requests, to help when streaming data.
  44  *
  45  * Key parts that must be USB-specific are protocols defining how the
  46  * read/write operations relate to the hardware state machines.  There
  47  * are two types of files.  One type is for the device, implementing ep0.
  48  * The other type is for each IN or OUT endpoint.  In both cases, the
  49  * user mode driver must configure the hardware before using it.
  50  *
  51  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  52  *   (by writing configuration and device descriptors).  Afterwards it
  53  *   may serve as a source of device events, used to handle all control
  54  *   requests other than basic enumeration.
  55  *
  56  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  57  *   called when each /dev/gadget/ep* file is configured (by writing
  58  *   endpoint descriptors).  Afterwards these files are used to write()
  59  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  60  *   direction" request is issued (like reading an IN endpoint).
  61  *
  62  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  63  * not possible on all hardware.  For example, precise fault handling with
  64  * respect to data left in endpoint fifos after aborted operations; or
  65  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  66  */
  67
  68 #define DRIVER_DESC     "USB Gadget filesystem"
  69 #define DRIVER_VERSION  "24 Aug 2004"
  70
  71 static const char driver_desc [] = DRIVER_DESC;
  72 static const char shortname [] = "gadgetfs";
  73
  74 MODULE_DESCRIPTION (DRIVER_DESC);
  75 MODULE_AUTHOR ("David Brownell");
  76 MODULE_LICENSE ("GPL");
  77
  78 static int ep_open(struct inode *, struct file *);
  79
  80
  81 /*----------------------------------------------------------------------*/
  82
  83 #define GADGETFS_MAGIC          0xaee71ee7
  84
  85 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  86 enum ep0_state {
  87         /* DISBLED is the initial state.
  88          */
  89         STATE_DEV_DISABLED = 0,
  90
  91         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
  92          * ep0/device i/o modes and binding to the controller.  Driver
  93          * must always write descriptors to initialize the device, then
  94          * the device becomes UNCONNECTED until enumeration.
  95          */
  96         STATE_DEV_OPENED,
  97
  98         /* From then on, ep0 fd is in either of two basic modes:
  99          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
 100          * - SETUP: read/write will transfer control data and succeed;
 101          *   or if "wrong direction", performs protocol stall
 102          */
 103         STATE_DEV_UNCONNECTED,
 104         STATE_DEV_CONNECTED,
 105         STATE_DEV_SETUP,
 106
 107         /* UNBOUND means the driver closed ep0, so the device won't be
 108          * accessible again (DEV_DISABLED) until all fds are closed.
 109          */
 110         STATE_DEV_UNBOUND,
 111 };
 112
 113 /* enough for the whole queue: most events invalidate others */
 114 #define N_EVENT                 5
 115
 116 #define RBUF_SIZE               256
 117
 118 struct dev_data {
 119         spinlock_t                      lock;
 120         atomic_t                        count;
 121         int                             udc_usage;
 122         enum ep0_state                  state;          /* P: lock */
 123         struct usb_gadgetfs_event       event [N_EVENT];
 124         unsigned                        ev_next;
 125         struct fasync_struct            *fasync;
 126         u8                              current_config;
 127
 128         /* drivers reading ep0 MUST handle control requests (SETUP)
 129          * reported that way; else the host will time out.
 130          */
 131         unsigned                        usermode_setup : 1,
 132                                         setup_in : 1,
 133                                         setup_can_stall : 1,
 134                                         setup_out_ready : 1,
 135                                         setup_out_error : 1,
 136                                         setup_abort : 1;
 137         unsigned                        setup_wLength;
 138
 139         /* the rest is basically write-once */
 140         struct usb_config_descriptor    *config, *hs_config;
 141         struct usb_device_descriptor    *dev;
 142         struct usb_request              *req;
 143         struct usb_gadget               *gadget;
 144         struct list_head                epfiles;
 145         void                            *buf;
 146         wait_queue_head_t               wait;
 147         struct super_block              *sb;
 148         struct dentry                   *dentry;
 149
 150         /* except this scratch i/o buffer for ep0 */
 151         u8                              rbuf[RBUF_SIZE];
 152 };
 153
 154 static inline void get_dev (struct dev_data *data)
 155 {
 156         atomic_inc (&data->count);
 157 }
 158
 159 static void put_dev (struct dev_data *data)
 160 {
 161         if (likely (!atomic_dec_and_test (&data->count)))
 162                 return;
 163         /* needs no more cleanup */
 164         BUG_ON (waitqueue_active (&data->wait));
 165         kfree (data);
 166 }
 167
 168 static struct dev_data *dev_new (void)
 169 {
 170         struct dev_data         *dev;
 171
 172         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 173         if (!dev)
 174                 return NULL;
 175         dev->state = STATE_DEV_DISABLED;
 176         atomic_set (&dev->count, 1);
 177         spin_lock_init (&dev->lock);
 178         INIT_LIST_HEAD (&dev->epfiles);
 179         init_waitqueue_head (&dev->wait);
 180         return dev;
 181 }
 182
 183 /*----------------------------------------------------------------------*/
 184
 185 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 186 enum ep_state {
 187         STATE_EP_DISABLED = 0,
 188         STATE_EP_READY,
 189         STATE_EP_ENABLED,
 190         STATE_EP_UNBOUND,
 191 };
 192
 193 struct ep_data {
 194         struct mutex                    lock;
 195         enum ep_state                   state;
 196         atomic_t                        count;
 197         struct dev_data                 *dev;
 198         /* must hold dev->lock before accessing ep or req */
 199         struct usb_ep                   *ep;
 200         struct usb_request              *req;
 201         ssize_t                         status;
 202         char                            name [16];
 203         struct usb_endpoint_descriptor  desc, hs_desc;
 204         struct list_head                epfiles;
 205         wait_queue_head_t               wait;
 206         struct dentry                   *dentry;
 207 };
 208
 209 static inline void get_ep (struct ep_data *data)
 210 {
 211         atomic_inc (&data->count);
 212 }
 213
 214 static void put_ep (struct ep_data *data)
 215 {
 216         if (likely (!atomic_dec_and_test (&data->count)))
 217                 return;
 218         put_dev (data->dev);
 219         /* needs no more cleanup */
 220         BUG_ON (!list_empty (&data->epfiles));
 221         BUG_ON (waitqueue_active (&data->wait));
 222         kfree (data);
 223 }
 224
 225 /*----------------------------------------------------------------------*/
 226
 227 /* most "how to use the hardware" policy choices are in userspace:
 228  * mapping endpoint roles (which the driver needs) to the capabilities
 229  * which the usb controller has.  most of those capabilities are exposed
 230  * implicitly, starting with the driver name and then endpoint names.
 231  */
 232
 233 static const char *CHIP;
 234
 235 /*----------------------------------------------------------------------*/
 236
 237 /* NOTE:  don't use dev_printk calls before binding to the gadget
 238  * at the end of ep0 configuration, or after unbind.
 239  */
 240
 241 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 242 #define xprintk(d,level,fmt,args...) \
 243         printk(level "%s: " fmt , shortname , ## args)
 244
 245 #ifdef DEBUG
 246 #define DBG(dev,fmt,args...) \
 247         xprintk(dev , KERN_DEBUG , fmt , ## args)
 248 #else
 249 #define DBG(dev,fmt,args...) \
 250         do { } while (0)
 251 #endif /* DEBUG */
 252
 253 #ifdef VERBOSE_DEBUG
 254 #define VDEBUG  DBG
 255 #else
 256 #define VDEBUG(dev,fmt,args...) \
 257         do { } while (0)
 258 #endif /* DEBUG */
 259
 260 #define ERROR(dev,fmt,args...) \
 261         xprintk(dev , KERN_ERR , fmt , ## args)
 262 #define INFO(dev,fmt,args...) \
 263         xprintk(dev , KERN_INFO , fmt , ## args)
 264
 265
 266 /*----------------------------------------------------------------------*/
 267
 268 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 269  *
 270  * After opening, configure non-control endpoints.  Then use normal
 271  * stream read() and write() requests; and maybe ioctl() to get more
 272  * precise FIFO status when recovering from cancellation.
 273  */
 274
 275 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 276 {
 277         struct ep_data  *epdata = ep->driver_data;
 278
 279         if (!req->context)
 280                 return;
 281         if (req->status)
 282                 epdata->status = req->status;
 283         else
 284                 epdata->status = req->actual;
 285         complete ((struct completion *)req->context);
 286 }
 287
 288 /* tasklock endpoint, returning when it's connected.
 289  * still need dev->lock to use epdata->ep.
 290  */
 291 static int
 292 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 293 {
 294         int     val;
 295
 296         if (f_flags & O_NONBLOCK) {
 297                 if (!mutex_trylock(&epdata->lock))
 298                         goto nonblock;
 299                 if (epdata->state != STATE_EP_ENABLED &&
 300                     (!is_write || epdata->state != STATE_EP_READY)) {
 301                         mutex_unlock(&epdata->lock);
 302 nonblock:
 303                         val = -EAGAIN;
 304                 } else
 305                         val = 0;
 306                 return val;
 307         }
 308
 309         val = mutex_lock_interruptible(&epdata->lock);
 310         if (val < 0)
 311                 return val;
 312
 313         switch (epdata->state) {
 314         case STATE_EP_ENABLED:
 315                 return 0;
 316         case STATE_EP_READY:                    /* not configured yet */
 317                 if (is_write)
 318                         return 0;
 319                 // FALLTHRU
 320         case STATE_EP_UNBOUND:                  /* clean disconnect */
 321                 break;
 322         // case STATE_EP_DISABLED:              /* "can't happen" */
 323         default:                                /* error! */
 324                 pr_debug ("%s: ep %p not available, state %d\n",
 325                                 shortname, epdata, epdata->state);
 326         }
 327         mutex_unlock(&epdata->lock);
 328         return -ENODEV;
 329 }
 330
 331 static ssize_t
 332 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 333 {
 334         DECLARE_COMPLETION_ONSTACK (done);
 335         int value;
 336
 337         spin_lock_irq (&epdata->dev->lock);
 338         if (likely (epdata->ep != NULL)) {
 339                 struct usb_request      *req = epdata->req;
 340
 341                 req->context = &done;
 342                 req->complete = epio_complete;
 343                 req->buf = buf;
 344                 req->length = len;
 345                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 346         } else
 347                 value = -ENODEV;
 348         spin_unlock_irq (&epdata->dev->lock);
 349
 350         if (likely (value == 0)) {
 351                 value = wait_event_interruptible (done.wait, done.done);
 352                 if (value != 0) {
 353                         spin_lock_irq (&epdata->dev->lock);
 354                         if (likely (epdata->ep != NULL)) {
 355                                 DBG (epdata->dev, "%s i/o interrupted\n",
 356                                                 epdata->name);
 357                                 usb_ep_dequeue (epdata->ep, epdata->req);
 358                                 spin_unlock_irq (&epdata->dev->lock);
 359
 360                                 wait_event (done.wait, done.done);
 361                                 if (epdata->status == -ECONNRESET)
 362                                         epdata->status = -EINTR;
 363                         } else {
 364                                 spin_unlock_irq (&epdata->dev->lock);
 365
 366                                 DBG (epdata->dev, "endpoint gone\n");
 367                                 epdata->status = -ENODEV;
 368                         }
 369                 }
 370                 return epdata->status;
 371         }
 372         return value;
 373 }
 374
 375 static int
 376 ep_release (struct inode *inode, struct file *fd)
 377 {
 378         struct ep_data          *data = fd->private_data;
 379         int value;
 380
 381         value = mutex_lock_interruptible(&data->lock);
 382         if (value < 0)
 383                 return value;
 384
 385         /* clean up if this can be reopened */
 386         if (data->state != STATE_EP_UNBOUND) {
 387                 data->state = STATE_EP_DISABLED;
 388                 data->desc.bDescriptorType = 0;
 389                 data->hs_desc.bDescriptorType = 0;
 390                 usb_ep_disable(data->ep);
 391         }
 392         mutex_unlock(&data->lock);
 393         put_ep (data);
 394         return 0;
 395 }
 396
 397 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 398 {
 399         struct ep_data          *data = fd->private_data;
 400         int                     status;
 401
 402         if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
 403                 return status;
 404
 405         spin_lock_irq (&data->dev->lock);
 406         if (likely (data->ep != NULL)) {
 407                 switch (code) {
 408                 case GADGETFS_FIFO_STATUS:
 409                         status = usb_ep_fifo_status (data->ep);
 410                         break;
 411                 case GADGETFS_FIFO_FLUSH:
 412                         usb_ep_fifo_flush (data->ep);
 413                         break;
 414                 case GADGETFS_CLEAR_HALT:
 415                         status = usb_ep_clear_halt (data->ep);
 416                         break;
 417                 default:
 418                         status = -ENOTTY;
 419                 }
 420         } else
 421                 status = -ENODEV;
 422         spin_unlock_irq (&data->dev->lock);
 423         mutex_unlock(&data->lock);
 424         return status;
 425 }
 426
 427 /*----------------------------------------------------------------------*/
 428
 429 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 430
 431 struct kiocb_priv {
 432         struct usb_request      *req;
 433         struct ep_data          *epdata;
 434         struct kiocb            *iocb;
 435         struct mm_struct        *mm;
 436         struct work_struct      work;
 437         void                    *buf;
 438         struct iov_iter         to;
 439         const void              *to_free;
 440         unsigned                actual;
 441 };
 442
 443 static int ep_aio_cancel(struct kiocb *iocb)
 444 {
 445         struct kiocb_priv       *priv = iocb->private;
 446         struct ep_data          *epdata;
 447         int                     value;
 448
 449         local_irq_disable();
 450         epdata = priv->epdata;
 451         // spin_lock(&epdata->dev->lock);
 452         if (likely(epdata && epdata->ep && priv->req))
 453                 value = usb_ep_dequeue (epdata->ep, priv->req);
 454         else
 455                 value = -EINVAL;
 456         // spin_unlock(&epdata->dev->lock);
 457         local_irq_enable();
 458
 459         return value;
 460 }
 461
 462 static void ep_user_copy_worker(struct work_struct *work)
 463 {
 464         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 465         struct mm_struct *mm = priv->mm;
 466         struct kiocb *iocb = priv->iocb;
 467         size_t ret;
 468
 469         use_mm(mm);
 470         ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
 471         unuse_mm(mm);
 472         if (!ret)
 473                 ret = -EFAULT;
 474
 475         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 476         iocb->ki_complete(iocb, ret, ret);
 477
 478         kfree(priv->buf);
 479         kfree(priv->to_free);
 480         kfree(priv);
 481 }
 482
 483 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 484 {
 485         struct kiocb            *iocb = req->context;
 486         struct kiocb_priv       *priv = iocb->private;
 487         struct ep_data          *epdata = priv->epdata;
 488
 489         /* lock against disconnect (and ideally, cancel) */
 490         spin_lock(&epdata->dev->lock);
 491         priv->req = NULL;
 492         priv->epdata = NULL;
 493
 494         /* if this was a write or a read returning no data then we
 495          * don't need to copy anything to userspace, so we can
 496          * complete the aio request immediately.
 497          */
 498         if (priv->to_free == NULL || unlikely(req->actual == 0)) {
 499                 kfree(req->buf);
 500                 kfree(priv->to_free);
 501                 kfree(priv);
 502                 iocb->private = NULL;
 503                 /* aio_complete() reports bytes-transferred _and_ faults */
 504
 505                 iocb->ki_complete(iocb, req->actual ? req->actual : req->status,
 506                                 req->status);
 507         } else {
 508                 /* ep_copy_to_user() won't report both; we hide some faults */
 509                 if (unlikely(0 != req->status))
 510                         DBG(epdata->dev, "%s fault %d len %d\n",
 511                                 ep->name, req->status, req->actual);
 512
 513                 priv->buf = req->buf;
 514                 priv->actual = req->actual;
 515                 INIT_WORK(&priv->work, ep_user_copy_worker);
 516                 schedule_work(&priv->work);
 517         }
 518
 519         usb_ep_free_request(ep, req);
 520         spin_unlock(&epdata->dev->lock);
 521         put_ep(epdata);
 522 }
 523
 524 static ssize_t ep_aio(struct kiocb *iocb,
 525                       struct kiocb_priv *priv,
 526                       struct ep_data *epdata,
 527                       char *buf,
 528                       size_t len)
 529 {
 530         struct usb_request *req;
 531         ssize_t value;
 532
 533         iocb->private = priv;
 534         priv->iocb = iocb;
 535
 536         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 537         get_ep(epdata);
 538         priv->epdata = epdata;
 539         priv->actual = 0;
 540         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 541
 542         /* each kiocb is coupled to one usb_request, but we can't
 543          * allocate or submit those if the host disconnected.
 544          */
 545         spin_lock_irq(&epdata->dev->lock);
 546         value = -ENODEV;
 547         if (unlikely(epdata->ep == NULL))
 548                 goto fail;
 549
 550         req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 551         value = -ENOMEM;
 552         if (unlikely(!req))
 553                 goto fail;
 554
 555         priv->req = req;
 556         req->buf = buf;
 557         req->length = len;
 558         req->complete = ep_aio_complete;
 559         req->context = iocb;
 560         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 561         if (unlikely(0 != value)) {
 562                 usb_ep_free_request(epdata->ep, req);
 563                 goto fail;
 564         }
 565         spin_unlock_irq(&epdata->dev->lock);
 566         return -EIOCBQUEUED;
 567
 568 fail:
 569         spin_unlock_irq(&epdata->dev->lock);
 570         kfree(priv->to_free);
 571         kfree(priv);
 572         put_ep(epdata);
 573         return value;
 574 }
 575
 576 static ssize_t
 577 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 578 {
 579         struct file *file = iocb->ki_filp;
 580         struct ep_data *epdata = file->private_data;
 581         size_t len = iov_iter_count(to);
 582         ssize_t value;
 583         char *buf;
 584
 585         if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
 586                 return value;
 587
 588         /* halt any endpoint by doing a "wrong direction" i/o call */
 589         if (usb_endpoint_dir_in(&epdata->desc)) {
 590                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 591                     !is_sync_kiocb(iocb)) {
 592                         mutex_unlock(&epdata->lock);
 593                         return -EINVAL;
 594                 }
 595                 DBG (epdata->dev, "%s halt\n", epdata->name);
 596                 spin_lock_irq(&epdata->dev->lock);
 597                 if (likely(epdata->ep != NULL))
 598                         usb_ep_set_halt(epdata->ep);
 599                 spin_unlock_irq(&epdata->dev->lock);
 600                 mutex_unlock(&epdata->lock);
 601                 return -EBADMSG;
 602         }
 603
 604         buf = kmalloc(len, GFP_KERNEL);
 605         if (unlikely(!buf)) {
 606                 mutex_unlock(&epdata->lock);
 607                 return -ENOMEM;
 608         }
 609         if (is_sync_kiocb(iocb)) {
 610                 value = ep_io(epdata, buf, len);
 611                 if (value >= 0 && copy_to_iter(buf, value, to))
 612                         value = -EFAULT;
 613         } else {
 614                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 615                 value = -ENOMEM;
 616                 if (!priv)
 617                         goto fail;
 618                 priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
 619                 if (!priv->to_free) {
 620                         kfree(priv);
 621                         goto fail;
 622                 }
 623                 value = ep_aio(iocb, priv, epdata, buf, len);
 624                 if (value == -EIOCBQUEUED)
 625                         buf = NULL;
 626         }
 627 fail:
 628         kfree(buf);
 629         mutex_unlock(&epdata->lock);
 630         return value;
 631 }
 632
 633 static ssize_t ep_config(struct ep_data *, const char *, size_t);
 634
 635 static ssize_t
 636 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 637 {
 638         struct file *file = iocb->ki_filp;
 639         struct ep_data *epdata = file->private_data;
 640         size_t len = iov_iter_count(from);
 641         bool configured;
 642         ssize_t value;
 643         char *buf;
 644
 645         if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
 646                 return value;
 647
 648         configured = epdata->state == STATE_EP_ENABLED;
 649
 650         /* halt any endpoint by doing a "wrong direction" i/o call */
 651         if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
 652                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 653                     !is_sync_kiocb(iocb)) {
 654                         mutex_unlock(&epdata->lock);
 655                         return -EINVAL;
 656                 }
 657                 DBG (epdata->dev, "%s halt\n", epdata->name);
 658                 spin_lock_irq(&epdata->dev->lock);
 659                 if (likely(epdata->ep != NULL))
 660                         usb_ep_set_halt(epdata->ep);
 661                 spin_unlock_irq(&epdata->dev->lock);
 662                 mutex_unlock(&epdata->lock);
 663                 return -EBADMSG;
 664         }
 665
 666         buf = kmalloc(len, GFP_KERNEL);
 667         if (unlikely(!buf)) {
 668                 mutex_unlock(&epdata->lock);
 669                 return -ENOMEM;
 670         }
 671
 672         if (unlikely(copy_from_iter(buf, len, from) != len)) {
 673                 value = -EFAULT;
 674                 goto out;
 675         }
 676
 677         if (unlikely(!configured)) {
 678                 value = ep_config(epdata, buf, len);
 679         } else if (is_sync_kiocb(iocb)) {
 680                 value = ep_io(epdata, buf, len);
 681         } else {
 682                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 683                 value = -ENOMEM;
 684                 if (priv) {
 685                         value = ep_aio(iocb, priv, epdata, buf, len);
 686                         if (value == -EIOCBQUEUED)
 687                                 buf = NULL;
 688                 }
 689         }
 690 out:
 691         kfree(buf);
 692         mutex_unlock(&epdata->lock);
 693         return value;
 694 }
 695
 696 /*----------------------------------------------------------------------*/
 697
 698 /* used after endpoint configuration */
 699 static const struct file_operations ep_io_operations = {
 700         .owner =        THIS_MODULE,
 701
 702         .open =         ep_open,
 703         .release =      ep_release,
 704         .llseek =       no_llseek,
 705         .unlocked_ioctl = ep_ioctl,
 706         .read_iter =    ep_read_iter,
 707         .write_iter =   ep_write_iter,
 708 };
 709
 710 /* ENDPOINT INITIALIZATION
 711  *
 712  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 713  *     status = write (fd, descriptors, sizeof descriptors)
 714  *
 715  * That write establishes the endpoint configuration, configuring
 716  * the controller to process bulk, interrupt, or isochronous transfers
 717  * at the right maxpacket size, and so on.
 718  *
 719  * The descriptors are message type 1, identified by a host order u32
 720  * at the beginning of what's written.  Descriptor order is: full/low
 721  * speed descriptor, then optional high speed descriptor.
 722  */
 723 static ssize_t
 724 ep_config (struct ep_data *data, const char *buf, size_t len)
 725 {
 726         struct usb_ep           *ep;
 727         u32                     tag;
 728         int                     value, length = len;
 729
 730         if (data->state != STATE_EP_READY) {
 731                 value = -EL2HLT;
 732                 goto fail;
 733         }
 734
 735         value = len;
 736         if (len < USB_DT_ENDPOINT_SIZE + 4)
 737                 goto fail0;
 738
 739         /* we might need to change message format someday */
 740         memcpy(&tag, buf, 4);
 741         if (tag != 1) {
 742                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 743                 goto fail0;
 744         }
 745         buf += 4;
 746         len -= 4;
 747
 748         /* NOTE:  audio endpoint extensions not accepted here;
 749          * just don't include the extra bytes.
 750          */
 751
 752         /* full/low speed descriptor, then high speed */
 753         memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
 754         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 755                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 756                 goto fail0;
 757         if (len != USB_DT_ENDPOINT_SIZE) {
 758                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 759                         goto fail0;
 760                 memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 761                         USB_DT_ENDPOINT_SIZE);
 762                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 763                                 || data->hs_desc.bDescriptorType
 764                                         != USB_DT_ENDPOINT) {
 765                         DBG(data->dev, "config %s, bad hs length or type\n",
 766                                         data->name);
 767                         goto fail0;
 768                 }
 769         }
 770
 771         spin_lock_irq (&data->dev->lock);
 772         if (data->dev->state == STATE_DEV_UNBOUND) {
 773                 value = -ENOENT;
 774                 goto gone;
 775         } else {
 776                 ep = data->ep;
 777                 if (ep == NULL) {
 778                         value = -ENODEV;
 779                         goto gone;
 780                 }
 781         }
 782         switch (data->dev->gadget->speed) {
 783         case USB_SPEED_LOW:
 784         case USB_SPEED_FULL:
 785                 ep->desc = &data->desc;
 786                 break;
 787         case USB_SPEED_HIGH:
 788                 /* fails if caller didn't provide that descriptor... */
 789                 ep->desc = &data->hs_desc;
 790                 break;
 791         default:
 792                 DBG(data->dev, "unconnected, %s init abandoned\n",
 793                                 data->name);
 794                 value = -EINVAL;
 795                 goto gone;
 796         }
 797         value = usb_ep_enable(ep);
 798         if (value == 0) {
 799                 data->state = STATE_EP_ENABLED;
 800                 value = length;
 801         }
 802 gone:
 803         spin_unlock_irq (&data->dev->lock);
 804         if (value < 0) {
 805 fail:
 806                 data->desc.bDescriptorType = 0;
 807                 data->hs_desc.bDescriptorType = 0;
 808         }
 809         return value;
 810 fail0:
 811         value = -EINVAL;
 812         goto fail;
 813 }
 814
 815 static int
 816 ep_open (struct inode *inode, struct file *fd)
 817 {
 818         struct ep_data          *data = inode->i_private;
 819         int                     value = -EBUSY;
 820
 821         if (mutex_lock_interruptible(&data->lock) != 0)
 822                 return -EINTR;
 823         spin_lock_irq (&data->dev->lock);
 824         if (data->dev->state == STATE_DEV_UNBOUND)
 825                 value = -ENOENT;
 826         else if (data->state == STATE_EP_DISABLED) {
 827                 value = 0;
 828                 data->state = STATE_EP_READY;
 829                 get_ep (data);
 830                 fd->private_data = data;
 831                 VDEBUG (data->dev, "%s ready\n", data->name);
 832         } else
 833                 DBG (data->dev, "%s state %d\n",
 834                         data->name, data->state);
 835         spin_unlock_irq (&data->dev->lock);
 836         mutex_unlock(&data->lock);
 837         return value;
 838 }
 839
 840 /*----------------------------------------------------------------------*/
 841
 842 /* EP0 IMPLEMENTATION can be partly in userspace.
 843  *
 844  * Drivers that use this facility receive various events, including
 845  * control requests the kernel doesn't handle.  Drivers that don't
 846  * use this facility may be too simple-minded for real applications.
 847  */
 848
 849 static inline void ep0_readable (struct dev_data *dev)
 850 {
 851         wake_up (&dev->wait);
 852         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 853 }
 854
 855 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 856 {
 857         struct dev_data         *dev = ep->driver_data;
 858
 859         if (req->buf != dev->rbuf) {
 860                 kfree(req->buf);
 861                 req->buf = dev->rbuf;
 862         }
 863         req->complete = epio_complete;
 864         dev->setup_out_ready = 0;
 865 }
 866
 867 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 868 {
 869         struct dev_data         *dev = ep->driver_data;
 870         unsigned long           flags;
 871         int                     free = 1;
 872
 873         /* for control OUT, data must still get to userspace */
 874         spin_lock_irqsave(&dev->lock, flags);
 875         if (!dev->setup_in) {
 876                 dev->setup_out_error = (req->status != 0);
 877                 if (!dev->setup_out_error)
 878                         free = 0;
 879                 dev->setup_out_ready = 1;
 880                 ep0_readable (dev);
 881         }
 882
 883         /* clean up as appropriate */
 884         if (free && req->buf != &dev->rbuf)
 885                 clean_req (ep, req);
 886         req->complete = epio_complete;
 887         spin_unlock_irqrestore(&dev->lock, flags);
 888 }
 889
 890 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 891 {
 892         struct dev_data *dev = ep->driver_data;
 893
 894         if (dev->setup_out_ready) {
 895                 DBG (dev, "ep0 request busy!\n");
 896                 return -EBUSY;
 897         }
 898         if (len > sizeof (dev->rbuf))
 899                 req->buf = kmalloc(len, GFP_ATOMIC);
 900         if (req->buf == NULL) {
 901                 req->buf = dev->rbuf;
 902                 return -ENOMEM;
 903         }
 904         req->complete = ep0_complete;
 905         req->length = len;
 906         req->zero = 0;
 907         return 0;
 908 }
 909
 910 static ssize_t
 911 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 912 {
 913         struct dev_data                 *dev = fd->private_data;
 914         ssize_t                         retval;
 915         enum ep0_state                  state;
 916
 917         spin_lock_irq (&dev->lock);
 918         if (dev->state <= STATE_DEV_OPENED) {
 919                 retval = -EINVAL;
 920                 goto done;
 921         }
 922
 923         /* report fd mode change before acting on it */
 924         if (dev->setup_abort) {
 925                 dev->setup_abort = 0;
 926                 retval = -EIDRM;
 927                 goto done;
 928         }
 929
 930         /* control DATA stage */
 931         if ((state = dev->state) == STATE_DEV_SETUP) {
 932
 933                 if (dev->setup_in) {            /* stall IN */
 934                         VDEBUG(dev, "ep0in stall\n");
 935                         (void) usb_ep_set_halt (dev->gadget->ep0);
 936                         retval = -EL2HLT;
 937                         dev->state = STATE_DEV_CONNECTED;
 938
 939                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
 940                         struct usb_ep           *ep = dev->gadget->ep0;
 941                         struct usb_request      *req = dev->req;
 942
 943                         if ((retval = setup_req (ep, req, 0)) == 0) {
 944                                 ++dev->udc_usage;
 945                                 spin_unlock_irq (&dev->lock);
 946                                 retval = usb_ep_queue (ep, req, GFP_KERNEL);
 947                                 spin_lock_irq (&dev->lock);
 948                                 --dev->udc_usage;
 949                         }
 950                         dev->state = STATE_DEV_CONNECTED;
 951
 952                         /* assume that was SET_CONFIGURATION */
 953                         if (dev->current_config) {
 954                                 unsigned power;
 955
 956                                 if (gadget_is_dualspeed(dev->gadget)
 957                                                 && (dev->gadget->speed
 958                                                         == USB_SPEED_HIGH))
 959                                         power = dev->hs_config->bMaxPower;
 960                                 else
 961                                         power = dev->config->bMaxPower;
 962                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
 963                         }
 964
 965                 } else {                        /* collect OUT data */
 966                         if ((fd->f_flags & O_NONBLOCK) != 0
 967                                         && !dev->setup_out_ready) {
 968                                 retval = -EAGAIN;
 969                                 goto done;
 970                         }
 971                         spin_unlock_irq (&dev->lock);
 972                         retval = wait_event_interruptible (dev->wait,
 973                                         dev->setup_out_ready != 0);
 974
 975                         /* FIXME state could change from under us */
 976                         spin_lock_irq (&dev->lock);
 977                         if (retval)
 978                                 goto done;
 979
 980                         if (dev->state != STATE_DEV_SETUP) {
 981                                 retval = -ECANCELED;
 982                                 goto done;
 983                         }
 984                         dev->state = STATE_DEV_CONNECTED;
 985
 986                         if (dev->setup_out_error)
 987                                 retval = -EIO;
 988                         else {
 989                                 len = min (len, (size_t)dev->req->actual);
 990                                 ++dev->udc_usage;
 991                                 spin_unlock_irq(&dev->lock);
 992                                 if (copy_to_user (buf, dev->req->buf, len))
 993                                         retval = -EFAULT;
 994                                 else
 995                                         retval = len;
 996                                 spin_lock_irq(&dev->lock);
 997                                 --dev->udc_usage;
 998                                 clean_req (dev->gadget->ep0, dev->req);
 999                                 /* NOTE userspace can't yet choose to stall */
1000                         }
1001                 }
1002                 goto done;
1003         }
1004
1005         /* else normal: return event data */
1006         if (len < sizeof dev->event [0]) {
1007                 retval = -EINVAL;
1008                 goto done;
1009         }
1010         len -= len % sizeof (struct usb_gadgetfs_event);
1011         dev->usermode_setup = 1;
1012
1013 scan:
1014         /* return queued events right away */
1015         if (dev->ev_next != 0) {
1016                 unsigned                i, n;
1017
1018                 n = len / sizeof (struct usb_gadgetfs_event);
1019                 if (dev->ev_next < n)
1020                         n = dev->ev_next;
1021
1022                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1023                 for (i = 0; i < n; i++) {
1024                         if (dev->event [i].type == GADGETFS_SETUP) {
1025                                 dev->state = STATE_DEV_SETUP;
1026                                 n = i + 1;
1027                                 break;
1028                         }
1029                 }
1030                 spin_unlock_irq (&dev->lock);
1031                 len = n * sizeof (struct usb_gadgetfs_event);
1032                 if (copy_to_user (buf, &dev->event, len))
1033                         retval = -EFAULT;
1034                 else
1035                         retval = len;
1036                 if (len > 0) {
1037                         /* NOTE this doesn't guard against broken drivers;
1038                          * concurrent ep0 readers may lose events.
1039                          */
1040                         spin_lock_irq (&dev->lock);
1041                         if (dev->ev_next > n) {
1042                                 memmove(&dev->event[0], &dev->event[n],
1043                                         sizeof (struct usb_gadgetfs_event)
1044                                                 * (dev->ev_next - n));
1045                         }
1046                         dev->ev_next -= n;
1047                         spin_unlock_irq (&dev->lock);
1048                 }
1049                 return retval;
1050         }
1051         if (fd->f_flags & O_NONBLOCK) {
1052                 retval = -EAGAIN;
1053                 goto done;
1054         }
1055
1056         switch (state) {
1057         default:
1058                 DBG (dev, "fail %s, state %d\n", __func__, state);
1059                 retval = -ESRCH;
1060                 break;
1061         case STATE_DEV_UNCONNECTED:
1062         case STATE_DEV_CONNECTED:
1063                 spin_unlock_irq (&dev->lock);
1064                 DBG (dev, "%s wait\n", __func__);
1065
1066                 /* wait for events */
1067                 retval = wait_event_interruptible (dev->wait,
1068                                 dev->ev_next != 0);
1069                 if (retval < 0)
1070                         return retval;
1071                 spin_lock_irq (&dev->lock);
1072                 goto scan;
1073         }
1074
1075 done:
1076         spin_unlock_irq (&dev->lock);
1077         return retval;
1078 }
1079
1080 static struct usb_gadgetfs_event *
1081 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1082 {
1083         struct usb_gadgetfs_event       *event;
1084         unsigned                        i;
1085
1086         switch (type) {
1087         /* these events purge the queue */
1088         case GADGETFS_DISCONNECT:
1089                 if (dev->state == STATE_DEV_SETUP)
1090                         dev->setup_abort = 1;
1091                 // FALL THROUGH
1092         case GADGETFS_CONNECT:
1093                 dev->ev_next = 0;
1094                 break;
1095         case GADGETFS_SETUP:            /* previous request timed out */
1096         case GADGETFS_SUSPEND:          /* same effect */
1097                 /* these events can't be repeated */
1098                 for (i = 0; i != dev->ev_next; i++) {
1099                         if (dev->event [i].type != type)
1100                                 continue;
1101                         DBG(dev, "discard old event[%d] %d\n", i, type);
1102                         dev->ev_next--;
1103                         if (i == dev->ev_next)
1104                                 break;
1105                         /* indices start at zero, for simplicity */
1106                         memmove (&dev->event [i], &dev->event [i + 1],
1107                                 sizeof (struct usb_gadgetfs_event)
1108                                         * (dev->ev_next - i));
1109                 }
1110                 break;
1111         default:
1112                 BUG ();
1113         }
1114         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1115         event = &dev->event [dev->ev_next++];
1116         BUG_ON (dev->ev_next > N_EVENT);
1117         memset (event, 0, sizeof *event);
1118         event->type = type;
1119         return event;
1120 }
1121
1122 static ssize_t
1123 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1124 {
1125         struct dev_data         *dev = fd->private_data;
1126         ssize_t                 retval = -ESRCH;
1127
1128         /* report fd mode change before acting on it */
1129         if (dev->setup_abort) {
1130                 dev->setup_abort = 0;
1131                 retval = -EIDRM;
1132
1133         /* data and/or status stage for control request */
1134         } else if (dev->state == STATE_DEV_SETUP) {
1135
1136                 len = min_t(size_t, len, dev->setup_wLength);
1137                 if (dev->setup_in) {
1138                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1139                         if (retval == 0) {
1140                                 dev->state = STATE_DEV_CONNECTED;
1141                                 ++dev->udc_usage;
1142                                 spin_unlock_irq (&dev->lock);
1143                                 if (copy_from_user (dev->req->buf, buf, len))
1144                                         retval = -EFAULT;
1145                                 else {
1146                                         if (len < dev->setup_wLength)
1147                                                 dev->req->zero = 1;
1148                                         retval = usb_ep_queue (
1149                                                 dev->gadget->ep0, dev->req,
1150                                                 GFP_KERNEL);
1151                                 }
1152                                 spin_lock_irq(&dev->lock);
1153                                 --dev->udc_usage;
1154                                 if (retval < 0) {
1155                                         clean_req (dev->gadget->ep0, dev->req);
1156                                 } else
1157                                         retval = len;
1158
1159                                 return retval;
1160                         }
1161
1162                 /* can stall some OUT transfers */
1163                 } else if (dev->setup_can_stall) {
1164                         VDEBUG(dev, "ep0out stall\n");
1165                         (void) usb_ep_set_halt (dev->gadget->ep0);
1166                         retval = -EL2HLT;
1167                         dev->state = STATE_DEV_CONNECTED;
1168                 } else {
1169                         DBG(dev, "bogus ep0out stall!\n");
1170                 }
1171         } else
1172                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1173
1174         return retval;
1175 }
1176
1177 static int
1178 ep0_fasync (int f, struct file *fd, int on)
1179 {
1180         struct dev_data         *dev = fd->private_data;
1181         // caller must F_SETOWN before signal delivery happens
1182         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1183         return fasync_helper (f, fd, on, &dev->fasync);
1184 }
1185
1186 static struct usb_gadget_driver gadgetfs_driver;
1187
1188 static int
1189 dev_release (struct inode *inode, struct file *fd)
1190 {
1191         struct dev_data         *dev = fd->private_data;
1192
1193         /* closing ep0 === shutdown all */
1194
1195         usb_gadget_unregister_driver (&gadgetfs_driver);
1196
1197         /* at this point "good" hardware has disconnected the
1198          * device from USB; the host won't see it any more.
1199          * alternatively, all host requests will time out.
1200          */
1201
1202         kfree (dev->buf);
1203         dev->buf = NULL;
1204
1205         /* other endpoints were all decoupled from this device */
1206         spin_lock_irq(&dev->lock);
1207         dev->state = STATE_DEV_DISABLED;
1208         spin_unlock_irq(&dev->lock);
1209
1210         put_dev (dev);
1211         return 0;
1212 }
1213
1214 static unsigned int
1215 ep0_poll (struct file *fd, poll_table *wait)
1216 {
1217        struct dev_data         *dev = fd->private_data;
1218        int                     mask = 0;
1219
1220         if (dev->state <= STATE_DEV_OPENED)
1221                 return DEFAULT_POLLMASK;
1222
1223        poll_wait(fd, &dev->wait, wait);
1224
1225        spin_lock_irq (&dev->lock);
1226
1227        /* report fd mode change before acting on it */
1228        if (dev->setup_abort) {
1229                dev->setup_abort = 0;
1230                mask = POLLHUP;
1231                goto out;
1232        }
1233
1234        if (dev->state == STATE_DEV_SETUP) {
1235                if (dev->setup_in || dev->setup_can_stall)
1236                        mask = POLLOUT;
1237        } else {
1238                if (dev->ev_next != 0)
1239                        mask = POLLIN;
1240        }
1241 out:
1242        spin_unlock_irq(&dev->lock);
1243        return mask;
1244 }
1245
1246 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1247 {
1248         struct dev_data         *dev = fd->private_data;
1249         struct usb_gadget       *gadget = dev->gadget;
1250         long ret = -ENOTTY;
1251
1252         spin_lock_irq(&dev->lock);
1253         if (dev->state == STATE_DEV_OPENED ||
1254                         dev->state == STATE_DEV_UNBOUND) {
1255                 /* Not bound to a UDC */
1256         } else if (gadget->ops->ioctl) {
1257                 ++dev->udc_usage;
1258                 spin_unlock_irq(&dev->lock);
1259
1260                 ret = gadget->ops->ioctl (gadget, code, value);
1261
1262                 spin_lock_irq(&dev->lock);
1263                 --dev->udc_usage;
1264         }
1265         spin_unlock_irq(&dev->lock);
1266
1267         return ret;
1268 }
1269
1270 /*----------------------------------------------------------------------*/
1271
1272 /* The in-kernel gadget driver handles most ep0 issues, in particular
1273  * enumerating the single configuration (as provided from user space).
1274  *
1275  * Unrecognized ep0 requests may be handled in user space.
1276  */
1277
1278 static void make_qualifier (struct dev_data *dev)
1279 {
1280         struct usb_qualifier_descriptor         qual;
1281         struct usb_device_descriptor            *desc;
1282
1283         qual.bLength = sizeof qual;
1284         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1285         qual.bcdUSB = cpu_to_le16 (0x0200);
1286
1287         desc = dev->dev;
1288         qual.bDeviceClass = desc->bDeviceClass;
1289         qual.bDeviceSubClass = desc->bDeviceSubClass;
1290         qual.bDeviceProtocol = desc->bDeviceProtocol;
1291
1292         /* assumes ep0 uses the same value for both speeds ... */
1293         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1294
1295         qual.bNumConfigurations = 1;
1296         qual.bRESERVED = 0;
1297
1298         memcpy (dev->rbuf, &qual, sizeof qual);
1299 }
1300
1301 static int
1302 config_buf (struct dev_data *dev, u8 type, unsigned index)
1303 {
1304         int             len;
1305         int             hs = 0;
1306
1307         /* only one configuration */
1308         if (index > 0)
1309                 return -EINVAL;
1310
1311         if (gadget_is_dualspeed(dev->gadget)) {
1312                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1313                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1314                         hs = !hs;
1315         }
1316         if (hs) {
1317                 dev->req->buf = dev->hs_config;
1318                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1319         } else {
1320                 dev->req->buf = dev->config;
1321                 len = le16_to_cpu(dev->config->wTotalLength);
1322         }
1323         ((u8 *)dev->req->buf) [1] = type;
1324         return len;
1325 }
1326
1327 static int
1328 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1329 {
1330         struct dev_data                 *dev = get_gadget_data (gadget);
1331         struct usb_request              *req = dev->req;
1332         int                             value = -EOPNOTSUPP;
1333         struct usb_gadgetfs_event       *event;
1334         u16                             w_value = le16_to_cpu(ctrl->wValue);
1335         u16                             w_length = le16_to_cpu(ctrl->wLength);
1336
1337         if (w_length > RBUF_SIZE) {
1338                 if (ctrl->bRequestType & USB_DIR_IN) {
1339                         /* Cast away the const, we are going to overwrite on purpose. */
1340                         __le16 *temp = (__le16 *)&ctrl->wLength;
1341
1342                         *temp = cpu_to_le16(RBUF_SIZE);
1343                         w_length = RBUF_SIZE;
1344                 } else {
1345                         return value;
1346                 }
1347         }
1348
1349         spin_lock (&dev->lock);
1350         dev->setup_abort = 0;
1351         if (dev->state == STATE_DEV_UNCONNECTED) {
1352                 if (gadget_is_dualspeed(gadget)
1353                                 && gadget->speed == USB_SPEED_HIGH
1354                                 && dev->hs_config == NULL) {
1355                         spin_unlock(&dev->lock);
1356                         ERROR (dev, "no high speed config??\n");
1357                         return -EINVAL;
1358                 }
1359
1360                 dev->state = STATE_DEV_CONNECTED;
1361
1362                 INFO (dev, "connected\n");
1363                 event = next_event (dev, GADGETFS_CONNECT);
1364                 event->u.speed = gadget->speed;
1365                 ep0_readable (dev);
1366
1367         /* host may have given up waiting for response.  we can miss control
1368          * requests handled lower down (device/endpoint status and features);
1369          * then ep0_{read,write} will report the wrong status. controller
1370          * driver will have aborted pending i/o.
1371          */
1372         } else if (dev->state == STATE_DEV_SETUP)
1373                 dev->setup_abort = 1;
1374
1375         req->buf = dev->rbuf;
1376         req->context = NULL;
1377         switch (ctrl->bRequest) {
1378
1379         case USB_REQ_GET_DESCRIPTOR:
1380                 if (ctrl->bRequestType != USB_DIR_IN)
1381                         goto unrecognized;
1382                 switch (w_value >> 8) {
1383
1384                 case USB_DT_DEVICE:
1385                         value = min (w_length, (u16) sizeof *dev->dev);
1386                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1387                         req->buf = dev->dev;
1388                         break;
1389                 case USB_DT_DEVICE_QUALIFIER:
1390                         if (!dev->hs_config)
1391                                 break;
1392                         value = min (w_length, (u16)
1393                                 sizeof (struct usb_qualifier_descriptor));
1394                         make_qualifier (dev);
1395                         break;
1396                 case USB_DT_OTHER_SPEED_CONFIG:
1397                         // FALLTHROUGH
1398                 case USB_DT_CONFIG:
1399                         value = config_buf (dev,
1400                                         w_value >> 8,
1401                                         w_value & 0xff);
1402                         if (value >= 0)
1403                                 value = min (w_length, (u16) value);
1404                         break;
1405                 case USB_DT_STRING:
1406                         goto unrecognized;
1407
1408                 default:                // all others are errors
1409                         break;
1410                 }
1411                 break;
1412
1413         /* currently one config, two speeds */
1414         case USB_REQ_SET_CONFIGURATION:
1415                 if (ctrl->bRequestType != 0)
1416                         goto unrecognized;
1417                 if (0 == (u8) w_value) {
1418                         value = 0;
1419                         dev->current_config = 0;
1420                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1421                         // user mode expected to disable endpoints
1422                 } else {
1423                         u8      config, power;
1424
1425                         if (gadget_is_dualspeed(gadget)
1426                                         && gadget->speed == USB_SPEED_HIGH) {
1427                                 config = dev->hs_config->bConfigurationValue;
1428                                 power = dev->hs_config->bMaxPower;
1429                         } else {
1430                                 config = dev->config->bConfigurationValue;
1431                                 power = dev->config->bMaxPower;
1432                         }
1433
1434                         if (config == (u8) w_value) {
1435                                 value = 0;
1436                                 dev->current_config = config;
1437                                 usb_gadget_vbus_draw(gadget, 2 * power);
1438                         }
1439                 }
1440
1441                 /* report SET_CONFIGURATION like any other control request,
1442                  * except that usermode may not stall this.  the next
1443                  * request mustn't be allowed start until this finishes:
1444                  * endpoints and threads set up, etc.
1445                  *
1446                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1447                  * has bad/racey automagic that prevents synchronizing here.
1448                  * even kernel mode drivers often miss them.
1449                  */
1450                 if (value == 0) {
1451                         INFO (dev, "configuration #%d\n", dev->current_config);
1452                         usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1453                         if (dev->usermode_setup) {
1454                                 dev->setup_can_stall = 0;
1455                                 goto delegate;
1456                         }
1457                 }
1458                 break;
1459
1460 #ifndef CONFIG_USB_PXA25X
1461         /* PXA automagically handles this request too */
1462         case USB_REQ_GET_CONFIGURATION:
1463                 if (ctrl->bRequestType != 0x80)
1464                         goto unrecognized;
1465                 *(u8 *)req->buf = dev->current_config;
1466                 value = min (w_length, (u16) 1);
1467                 break;
1468 #endif
1469
1470         default:
1471 unrecognized:
1472                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1473                         dev->usermode_setup ? "delegate" : "fail",
1474                         ctrl->bRequestType, ctrl->bRequest,
1475                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1476
1477                 /* if there's an ep0 reader, don't stall */
1478                 if (dev->usermode_setup) {
1479                         dev->setup_can_stall = 1;
1480 delegate:
1481                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1482                                                 ? 1 : 0;
1483                         dev->setup_wLength = w_length;
1484                         dev->setup_out_ready = 0;
1485                         dev->setup_out_error = 0;
1486                         value = 0;
1487
1488                         /* read DATA stage for OUT right away */
1489                         if (unlikely (!dev->setup_in && w_length)) {
1490                                 value = setup_req (gadget->ep0, dev->req,
1491                                                         w_length);
1492                                 if (value < 0)
1493                                         break;
1494
1495                                 ++dev->udc_usage;
1496                                 spin_unlock (&dev->lock);
1497                                 value = usb_ep_queue (gadget->ep0, dev->req,
1498                                                         GFP_KERNEL);
1499                                 spin_lock (&dev->lock);
1500                                 --dev->udc_usage;
1501                                 if (value < 0) {
1502                                         clean_req (gadget->ep0, dev->req);
1503                                         break;
1504                                 }
1505
1506                                 /* we can't currently stall these */
1507                                 dev->setup_can_stall = 0;
1508                         }
1509
1510                         /* state changes when reader collects event */
1511                         event = next_event (dev, GADGETFS_SETUP);
1512                         event->u.setup = *ctrl;
1513                         ep0_readable (dev);
1514                         spin_unlock (&dev->lock);
1515                         return 0;
1516                 }
1517         }
1518
1519         /* proceed with data transfer and status phases? */
1520         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1521                 req->length = value;
1522                 req->zero = value < w_length;
1523
1524                 ++dev->udc_usage;
1525                 spin_unlock (&dev->lock);
1526                 value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1527                 spin_lock(&dev->lock);
1528                 --dev->udc_usage;
1529                 spin_unlock(&dev->lock);
1530                 if (value < 0) {
1531                         DBG (dev, "ep_queue --> %d\n", value);
1532                         req->status = 0;
1533                 }
1534                 return value;
1535         }
1536
1537         /* device stalls when value < 0 */
1538         spin_unlock (&dev->lock);
1539         return value;
1540 }
1541
1542 static void destroy_ep_files (struct dev_data *dev)
1543 {
1544         DBG (dev, "%s %d\n", __func__, dev->state);
1545
1546         /* dev->state must prevent interference */
1547         spin_lock_irq (&dev->lock);
1548         while (!list_empty(&dev->epfiles)) {
1549                 struct ep_data  *ep;
1550                 struct inode    *parent;
1551                 struct dentry   *dentry;
1552
1553                 /* break link to FS */
1554                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1555                 list_del_init (&ep->epfiles);
1556                 spin_unlock_irq (&dev->lock);
1557
1558                 dentry = ep->dentry;
1559                 ep->dentry = NULL;
1560                 parent = d_inode(dentry->d_parent);
1561
1562                 /* break link to controller */
1563                 mutex_lock(&ep->lock);
1564                 if (ep->state == STATE_EP_ENABLED)
1565                         (void) usb_ep_disable (ep->ep);
1566                 ep->state = STATE_EP_UNBOUND;
1567                 usb_ep_free_request (ep->ep, ep->req);
1568                 ep->ep = NULL;
1569                 mutex_unlock(&ep->lock);
1570
1571                 wake_up (&ep->wait);
1572                 put_ep (ep);
1573
1574                 /* break link to dcache */
1575                 mutex_lock (&parent->i_mutex);
1576                 d_delete (dentry);
1577                 dput (dentry);
1578                 mutex_unlock (&parent->i_mutex);
1579
1580                 spin_lock_irq (&dev->lock);
1581         }
1582         spin_unlock_irq (&dev->lock);
1583 }
1584
1585
1586 static struct dentry *
1587 gadgetfs_create_file (struct super_block *sb, char const *name,
1588                 void *data, const struct file_operations *fops);
1589
1590 static int activate_ep_files (struct dev_data *dev)
1591 {
1592         struct usb_ep   *ep;
1593         struct ep_data  *data;
1594
1595         gadget_for_each_ep (ep, dev->gadget) {
1596
1597                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1598                 if (!data)
1599                         goto enomem0;
1600                 data->state = STATE_EP_DISABLED;
1601                 mutex_init(&data->lock);
1602                 init_waitqueue_head (&data->wait);
1603
1604                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1605                 atomic_set (&data->count, 1);
1606                 data->dev = dev;
1607                 get_dev (dev);
1608
1609                 data->ep = ep;
1610                 ep->driver_data = data;
1611
1612                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1613                 if (!data->req)
1614                         goto enomem1;
1615
1616                 data->dentry = gadgetfs_create_file (dev->sb, data->name,
1617                                 data, &ep_io_operations);
1618                 if (!data->dentry)
1619                         goto enomem2;
1620                 list_add_tail (&data->epfiles, &dev->epfiles);
1621         }
1622         return 0;
1623
1624 enomem2:
1625         usb_ep_free_request (ep, data->req);
1626 enomem1:
1627         put_dev (dev);
1628         kfree (data);
1629 enomem0:
1630         DBG (dev, "%s enomem\n", __func__);
1631         destroy_ep_files (dev);
1632         return -ENOMEM;
1633 }
1634
1635 static void
1636 gadgetfs_unbind (struct usb_gadget *gadget)
1637 {
1638         struct dev_data         *dev = get_gadget_data (gadget);
1639
1640         DBG (dev, "%s\n", __func__);
1641
1642         spin_lock_irq (&dev->lock);
1643         dev->state = STATE_DEV_UNBOUND;
1644         while (dev->udc_usage > 0) {
1645                 spin_unlock_irq(&dev->lock);
1646                 usleep_range(1000, 2000);
1647                 spin_lock_irq(&dev->lock);
1648         }
1649         spin_unlock_irq (&dev->lock);
1650
1651         destroy_ep_files (dev);
1652         gadget->ep0->driver_data = NULL;
1653         set_gadget_data (gadget, NULL);
1654
1655         /* we've already been disconnected ... no i/o is active */
1656         if (dev->req)
1657                 usb_ep_free_request (gadget->ep0, dev->req);
1658         DBG (dev, "%s done\n", __func__);
1659         put_dev (dev);
1660 }
1661
1662 static struct dev_data          *the_device;
1663
1664 static int gadgetfs_bind(struct usb_gadget *gadget,
1665                 struct usb_gadget_driver *driver)
1666 {
1667         struct dev_data         *dev = the_device;
1668
1669         if (!dev)
1670                 return -ESRCH;
1671         if (0 != strcmp (CHIP, gadget->name)) {
1672                 pr_err("%s expected %s controller not %s\n",
1673                         shortname, CHIP, gadget->name);
1674                 return -ENODEV;
1675         }
1676
1677         set_gadget_data (gadget, dev);
1678         dev->gadget = gadget;
1679         gadget->ep0->driver_data = dev;
1680
1681         /* preallocate control response and buffer */
1682         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1683         if (!dev->req)
1684                 goto enomem;
1685         dev->req->context = NULL;
1686         dev->req->complete = epio_complete;
1687
1688         if (activate_ep_files (dev) < 0)
1689                 goto enomem;
1690
1691         INFO (dev, "bound to %s driver\n", gadget->name);
1692         spin_lock_irq(&dev->lock);
1693         dev->state = STATE_DEV_UNCONNECTED;
1694         spin_unlock_irq(&dev->lock);
1695         get_dev (dev);
1696         return 0;
1697
1698 enomem:
1699         gadgetfs_unbind (gadget);
1700         return -ENOMEM;
1701 }
1702
1703 static void
1704 gadgetfs_disconnect (struct usb_gadget *gadget)
1705 {
1706         struct dev_data         *dev = get_gadget_data (gadget);
1707         unsigned long           flags;
1708
1709         spin_lock_irqsave (&dev->lock, flags);
1710         if (dev->state == STATE_DEV_UNCONNECTED)
1711                 goto exit;
1712         dev->state = STATE_DEV_UNCONNECTED;
1713
1714         INFO (dev, "disconnected\n");
1715         next_event (dev, GADGETFS_DISCONNECT);
1716         ep0_readable (dev);
1717 exit:
1718         spin_unlock_irqrestore (&dev->lock, flags);
1719 }
1720
1721 static void
1722 gadgetfs_suspend (struct usb_gadget *gadget)
1723 {
1724         struct dev_data         *dev = get_gadget_data (gadget);
1725         unsigned long           flags;
1726
1727         INFO (dev, "suspended from state %d\n", dev->state);
1728         spin_lock_irqsave(&dev->lock, flags);
1729         switch (dev->state) {
1730         case STATE_DEV_SETUP:           // VERY odd... host died??
1731         case STATE_DEV_CONNECTED:
1732         case STATE_DEV_UNCONNECTED:
1733                 next_event (dev, GADGETFS_SUSPEND);
1734                 ep0_readable (dev);
1735                 /* FALLTHROUGH */
1736         default:
1737                 break;
1738         }
1739         spin_unlock_irqrestore(&dev->lock, flags);
1740 }
1741
1742 static struct usb_gadget_driver gadgetfs_driver = {
1743         .function       = (char *) driver_desc,
1744         .bind           = gadgetfs_bind,
1745         .unbind         = gadgetfs_unbind,
1746         .setup          = gadgetfs_setup,
1747         .reset          = gadgetfs_disconnect,
1748         .disconnect     = gadgetfs_disconnect,
1749         .suspend        = gadgetfs_suspend,
1750
1751         .driver = {
1752                 .name           = (char *) shortname,
1753         },
1754 };
1755
1756 /*----------------------------------------------------------------------*/
1757
1758 static void gadgetfs_nop(struct usb_gadget *arg) { }
1759
1760 static int gadgetfs_probe(struct usb_gadget *gadget,
1761                 struct usb_gadget_driver *driver)
1762 {
1763         CHIP = gadget->name;
1764         return -EISNAM;
1765 }
1766
1767 static struct usb_gadget_driver probe_driver = {
1768         .max_speed      = USB_SPEED_HIGH,
1769         .bind           = gadgetfs_probe,
1770         .unbind         = gadgetfs_nop,
1771         .setup          = (void *)gadgetfs_nop,
1772         .disconnect     = gadgetfs_nop,
1773         .driver = {
1774                 .name           = "nop",
1775         },
1776 };
1777
1778
1779 /* DEVICE INITIALIZATION
1780  *
1781  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1782  *     status = write (fd, descriptors, sizeof descriptors)
1783  *
1784  * That write establishes the device configuration, so the kernel can
1785  * bind to the controller ... guaranteeing it can handle enumeration
1786  * at all necessary speeds.  Descriptor order is:
1787  *
1788  * . message tag (u32, host order) ... for now, must be zero; it
1789  *      would change to support features like multi-config devices
1790  * . full/low speed config ... all wTotalLength bytes (with interface,
1791  *      class, altsetting, endpoint, and other descriptors)
1792  * . high speed config ... all descriptors, for high speed operation;
1793  *      this one's optional except for high-speed hardware
1794  * . device descriptor
1795  *
1796  * Endpoints are not yet enabled. Drivers must wait until device
1797  * configuration and interface altsetting changes create
1798  * the need to configure (or unconfigure) them.
1799  *
1800  * After initialization, the device stays active for as long as that
1801  * $CHIP file is open.  Events must then be read from that descriptor,
1802  * such as configuration notifications.
1803  */
1804
1805 static int is_valid_config(struct usb_config_descriptor *config,
1806                 unsigned int total)
1807 {
1808         return config->bDescriptorType == USB_DT_CONFIG
1809                 && config->bLength == USB_DT_CONFIG_SIZE
1810                 && total >= USB_DT_CONFIG_SIZE
1811                 && config->bConfigurationValue != 0
1812                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1813                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1814         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1815         /* FIXME check lengths: walk to end */
1816 }
1817
1818 static ssize_t
1819 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1820 {
1821         struct dev_data         *dev = fd->private_data;
1822         ssize_t                 value, length = len;
1823         unsigned                total;
1824         u32                     tag;
1825         char                    *kbuf;
1826
1827         spin_lock_irq(&dev->lock);
1828         if (dev->state > STATE_DEV_OPENED) {
1829                 value = ep0_write(fd, buf, len, ptr);
1830                 spin_unlock_irq(&dev->lock);
1831                 return value;
1832         }
1833         spin_unlock_irq(&dev->lock);
1834
1835         if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1836             (len > PAGE_SIZE * 4))
1837                 return -EINVAL;
1838
1839         /* we might need to change message format someday */
1840         if (copy_from_user (&tag, buf, 4))
1841                 return -EFAULT;
1842         if (tag != 0)
1843                 return -EINVAL;
1844         buf += 4;
1845         length -= 4;
1846
1847         kbuf = memdup_user(buf, length);
1848         if (IS_ERR(kbuf))
1849                 return PTR_ERR(kbuf);
1850
1851         spin_lock_irq (&dev->lock);
1852         value = -EINVAL;
1853         if (dev->buf) {
1854                 kfree(kbuf);
1855                 goto fail;
1856         }
1857         dev->buf = kbuf;
1858
1859         /* full or low speed config */
1860         dev->config = (void *) kbuf;
1861         total = le16_to_cpu(dev->config->wTotalLength);
1862         if (!is_valid_config(dev->config, total) ||
1863                         total > length - USB_DT_DEVICE_SIZE)
1864                 goto fail;
1865         kbuf += total;
1866         length -= total;
1867
1868         /* optional high speed config */
1869         if (kbuf [1] == USB_DT_CONFIG) {
1870                 dev->hs_config = (void *) kbuf;
1871                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1872                 if (!is_valid_config(dev->hs_config, total) ||
1873                                 total > length - USB_DT_DEVICE_SIZE)
1874                         goto fail;
1875                 kbuf += total;
1876                 length -= total;
1877         } else {
1878                 dev->hs_config = NULL;
1879         }
1880
1881         /* could support multiple configs, using another encoding! */
1882
1883         /* device descriptor (tweaked for paranoia) */
1884         if (length != USB_DT_DEVICE_SIZE)
1885                 goto fail;
1886         dev->dev = (void *)kbuf;
1887         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1888                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1889                         || dev->dev->bNumConfigurations != 1)
1890                 goto fail;
1891         dev->dev->bNumConfigurations = 1;
1892         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1893
1894         /* triggers gadgetfs_bind(); then we can enumerate. */
1895         spin_unlock_irq (&dev->lock);
1896         if (dev->hs_config)
1897                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1898         else
1899                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1900
1901         value = usb_gadget_probe_driver(&gadgetfs_driver);
1902         if (value != 0) {
1903                 kfree (dev->buf);
1904                 dev->buf = NULL;
1905         } else {
1906                 /* at this point "good" hardware has for the first time
1907                  * let the USB the host see us.  alternatively, if users
1908                  * unplug/replug that will clear all the error state.
1909                  *
1910                  * note:  everything running before here was guaranteed
1911                  * to choke driver model style diagnostics.  from here
1912                  * on, they can work ... except in cleanup paths that
1913                  * kick in after the ep0 descriptor is closed.
1914                  */
1915                 value = len;
1916         }
1917         return value;
1918
1919 fail:
1920         spin_unlock_irq (&dev->lock);
1921         pr_debug ("%s: %s fail %Zd, %p\n", shortname, __func__, value, dev);
1922         kfree (dev->buf);
1923         dev->buf = NULL;
1924         return value;
1925 }
1926
1927 static int
1928 dev_open (struct inode *inode, struct file *fd)
1929 {
1930         struct dev_data         *dev = inode->i_private;
1931         int                     value = -EBUSY;
1932
1933         spin_lock_irq(&dev->lock);
1934         if (dev->state == STATE_DEV_DISABLED) {
1935                 dev->ev_next = 0;
1936                 dev->state = STATE_DEV_OPENED;
1937                 fd->private_data = dev;
1938                 get_dev (dev);
1939                 value = 0;
1940         }
1941         spin_unlock_irq(&dev->lock);
1942         return value;
1943 }
1944
1945 static const struct file_operations ep0_operations = {
1946         .llseek =       no_llseek,
1947
1948         .open =         dev_open,
1949         .read =         ep0_read,
1950         .write =        dev_config,
1951         .fasync =       ep0_fasync,
1952         .poll =         ep0_poll,
1953         .unlocked_ioctl = dev_ioctl,
1954         .release =      dev_release,
1955 };
1956
1957 /*----------------------------------------------------------------------*/
1958
1959 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1960  *
1961  * Mounting the filesystem creates a controller file, used first for
1962  * device configuration then later for event monitoring.
1963  */
1964
1965
1966 /* FIXME PAM etc could set this security policy without mount options
1967  * if epfiles inherited ownership and permissons from ep0 ...
1968  */
1969
1970 static unsigned default_uid;
1971 static unsigned default_gid;
1972 static unsigned default_perm = S_IRUSR | S_IWUSR;
1973
1974 module_param (default_uid, uint, 0644);
1975 module_param (default_gid, uint, 0644);
1976 module_param (default_perm, uint, 0644);
1977
1978
1979 static struct inode *
1980 gadgetfs_make_inode (struct super_block *sb,
1981                 void *data, const struct file_operations *fops,
1982                 int mode)
1983 {
1984         struct inode *inode = new_inode (sb);
1985
1986         if (inode) {
1987                 inode->i_ino = get_next_ino();
1988                 inode->i_mode = mode;
1989                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
1990                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
1991                 inode->i_atime = inode->i_mtime = inode->i_ctime
1992                                 = CURRENT_TIME;
1993                 inode->i_private = data;
1994                 inode->i_fop = fops;
1995         }
1996         return inode;
1997 }
1998
1999 /* creates in fs root directory, so non-renamable and non-linkable.
2000  * so inode and dentry are paired, until device reconfig.
2001  */
2002 static struct dentry *
2003 gadgetfs_create_file (struct super_block *sb, char const *name,
2004                 void *data, const struct file_operations *fops)
2005 {
2006         struct dentry   *dentry;
2007         struct inode    *inode;
2008
2009         dentry = d_alloc_name(sb->s_root, name);
2010         if (!dentry)
2011                 return NULL;
2012
2013         inode = gadgetfs_make_inode (sb, data, fops,
2014                         S_IFREG | (default_perm & S_IRWXUGO));
2015         if (!inode) {
2016                 dput(dentry);
2017                 return NULL;
2018         }
2019         d_add (dentry, inode);
2020         return dentry;
2021 }
2022
2023 static const struct super_operations gadget_fs_operations = {
2024         .statfs =       simple_statfs,
2025         .drop_inode =   generic_delete_inode,
2026 };
2027
2028 static int
2029 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
2030 {
2031         struct inode    *inode;
2032         struct dev_data *dev;
2033
2034         if (the_device)
2035                 return -ESRCH;
2036
2037         /* fake probe to determine $CHIP */
2038         CHIP = NULL;
2039         usb_gadget_probe_driver(&probe_driver);
2040         if (!CHIP)
2041                 return -ENODEV;
2042
2043         /* superblock */
2044         sb->s_blocksize = PAGE_CACHE_SIZE;
2045         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2046         sb->s_magic = GADGETFS_MAGIC;
2047         sb->s_op = &gadget_fs_operations;
2048         sb->s_time_gran = 1;
2049
2050         /* root inode */
2051         inode = gadgetfs_make_inode (sb,
2052                         NULL, &simple_dir_operations,
2053                         S_IFDIR | S_IRUGO | S_IXUGO);
2054         if (!inode)
2055                 goto Enomem;
2056         inode->i_op = &simple_dir_inode_operations;
2057         if (!(sb->s_root = d_make_root (inode)))
2058                 goto Enomem;
2059
2060         /* the ep0 file is named after the controller we expect;
2061          * user mode code can use it for sanity checks, like we do.
2062          */
2063         dev = dev_new ();
2064         if (!dev)
2065                 goto Enomem;
2066
2067         dev->sb = sb;
2068         dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2069         if (!dev->dentry) {
2070                 put_dev(dev);
2071                 goto Enomem;
2072         }
2073
2074         /* other endpoint files are available after hardware setup,
2075          * from binding to a controller.
2076          */
2077         the_device = dev;
2078         return 0;
2079
2080 Enomem:
2081         return -ENOMEM;
2082 }
2083
2084 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2085 static struct dentry *
2086 gadgetfs_mount (struct file_system_type *t, int flags,
2087                 const char *path, void *opts)
2088 {
2089         return mount_single (t, flags, opts, gadgetfs_fill_super);
2090 }
2091
2092 static void
2093 gadgetfs_kill_sb (struct super_block *sb)
2094 {
2095         kill_litter_super (sb);
2096         if (the_device) {
2097                 put_dev (the_device);
2098                 the_device = NULL;
2099         }
2100 }
2101
2102 /*----------------------------------------------------------------------*/
2103
2104 static struct file_system_type gadgetfs_type = {
2105         .owner          = THIS_MODULE,
2106         .name           = shortname,
2107         .mount          = gadgetfs_mount,
2108         .kill_sb        = gadgetfs_kill_sb,
2109 };
2110 MODULE_ALIAS_FS("gadgetfs");
2111
2112 /*----------------------------------------------------------------------*/
2113
2114 static int __init init (void)
2115 {
2116         int status;
2117
2118         status = register_filesystem (&gadgetfs_type);
2119         if (status == 0)
2120                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2121                         shortname, driver_desc);
2122         return status;
2123 }
2124 module_init (init);
2125
2126 static void __exit cleanup (void)
2127 {
2128         pr_debug ("unregister %s\n", shortname);
2129         unregister_filesystem (&gadgetfs_type);
2130 }
2131 module_exit (cleanup);
2132