drivers/usb/gadget/legacy/inode.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * inode.c -- user mode filesystem api for usb gadget controllers
   4  *
   5  * Copyright (C) 2003-2004 David Brownell
   6  * Copyright (C) 2003 Agilent Technologies
   7  */
   8
   9
  10 /* #define VERBOSE_DEBUG */
  11
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/fs.h>
  15 #include <linux/fs_context.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/uts.h>
  18 #include <linux/wait.h>
  19 #include <linux/compiler.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23 #include <linux/poll.h>
  24 #include <linux/kthread.h>
  25 #include <linux/aio.h>
  26 #include <linux/uio.h>
  27 #include <linux/refcount.h>
  28 #include <linux/delay.h>
  29 #include <linux/device.h>
  30 #include <linux/moduleparam.h>
  31
  32 #include <linux/usb/gadgetfs.h>
  33 #include <linux/usb/gadget.h>
  34
  35
  36 /*
  37  * The gadgetfs API maps each endpoint to a file descriptor so that you
  38  * can use standard synchronous read/write calls for I/O.  There's some
  39  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
  40  * drivers show how this works in practice.  You can also use AIO to
  41  * eliminate I/O gaps between requests, to help when streaming data.
  42  *
  43  * Key parts that must be USB-specific are protocols defining how the
  44  * read/write operations relate to the hardware state machines.  There
  45  * are two types of files.  One type is for the device, implementing ep0.
  46  * The other type is for each IN or OUT endpoint.  In both cases, the
  47  * user mode driver must configure the hardware before using it.
  48  *
  49  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
  50  *   (by writing configuration and device descriptors).  Afterwards it
  51  *   may serve as a source of device events, used to handle all control
  52  *   requests other than basic enumeration.
  53  *
  54  * - Then, after a SET_CONFIGURATION control request, ep_config() is
  55  *   called when each /dev/gadget/ep* file is configured (by writing
  56  *   endpoint descriptors).  Afterwards these files are used to write()
  57  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
  58  *   direction" request is issued (like reading an IN endpoint).
  59  *
  60  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
  61  * not possible on all hardware.  For example, precise fault handling with
  62  * respect to data left in endpoint fifos after aborted operations; or
  63  * selective clearing of endpoint halts, to implement SET_INTERFACE.
  64  */
  65
  66 #define DRIVER_DESC     "USB Gadget filesystem"
  67 #define DRIVER_VERSION  "24 Aug 2004"
  68
  69 static const char driver_desc [] = DRIVER_DESC;
  70 static const char shortname [] = "gadgetfs";
  71
  72 MODULE_DESCRIPTION (DRIVER_DESC);
  73 MODULE_AUTHOR ("David Brownell");
  74 MODULE_LICENSE ("GPL");
  75
  76 static int ep_open(struct inode *, struct file *);
  77
  78
  79 /*----------------------------------------------------------------------*/
  80
  81 #define GADGETFS_MAGIC          0xaee71ee7
  82
  83 /* /dev/gadget/$CHIP represents ep0 and the whole device */
  84 enum ep0_state {
  85         /* DISABLED is the initial state. */
  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         refcount_t                      count;
 116         int                             udc_usage;
 117         enum ep0_state                  state;          /* P: lock */
 118         struct usb_gadgetfs_event       event [N_EVENT];
 119         unsigned                        ev_next;
 120         struct fasync_struct            *fasync;
 121         u8                              current_config;
 122
 123         /* drivers reading ep0 MUST handle control requests (SETUP)
 124          * reported that way; else the host will time out.
 125          */
 126         unsigned                        usermode_setup : 1,
 127                                         setup_in : 1,
 128                                         setup_can_stall : 1,
 129                                         setup_out_ready : 1,
 130                                         setup_out_error : 1,
 131                                         setup_abort : 1,
 132                                         gadget_registered : 1;
 133         unsigned                        setup_wLength;
 134
 135         /* the rest is basically write-once */
 136         struct usb_config_descriptor    *config, *hs_config;
 137         struct usb_device_descriptor    *dev;
 138         struct usb_request              *req;
 139         struct usb_gadget               *gadget;
 140         struct list_head                epfiles;
 141         void                            *buf;
 142         wait_queue_head_t               wait;
 143         struct super_block              *sb;
 144         struct dentry                   *dentry;
 145
 146         /* except this scratch i/o buffer for ep0 */
 147         u8                              rbuf [256];
 148 };
 149
 150 static inline void get_dev (struct dev_data *data)
 151 {
 152         refcount_inc (&data->count);
 153 }
 154
 155 static void put_dev (struct dev_data *data)
 156 {
 157         if (likely (!refcount_dec_and_test (&data->count)))
 158                 return;
 159         /* needs no more cleanup */
 160         BUG_ON (waitqueue_active (&data->wait));
 161         kfree (data);
 162 }
 163
 164 static struct dev_data *dev_new (void)
 165 {
 166         struct dev_data         *dev;
 167
 168         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 169         if (!dev)
 170                 return NULL;
 171         dev->state = STATE_DEV_DISABLED;
 172         refcount_set (&dev->count, 1);
 173         spin_lock_init (&dev->lock);
 174         INIT_LIST_HEAD (&dev->epfiles);
 175         init_waitqueue_head (&dev->wait);
 176         return dev;
 177 }
 178
 179 /*----------------------------------------------------------------------*/
 180
 181 /* other /dev/gadget/$ENDPOINT files represent endpoints */
 182 enum ep_state {
 183         STATE_EP_DISABLED = 0,
 184         STATE_EP_READY,
 185         STATE_EP_ENABLED,
 186         STATE_EP_UNBOUND,
 187 };
 188
 189 struct ep_data {
 190         struct mutex                    lock;
 191         enum ep_state                   state;
 192         refcount_t                      count;
 193         struct dev_data                 *dev;
 194         /* must hold dev->lock before accessing ep or req */
 195         struct usb_ep                   *ep;
 196         struct usb_request              *req;
 197         ssize_t                         status;
 198         char                            name [16];
 199         struct usb_endpoint_descriptor  desc, hs_desc;
 200         struct list_head                epfiles;
 201         wait_queue_head_t               wait;
 202         struct dentry                   *dentry;
 203 };
 204
 205 static inline void get_ep (struct ep_data *data)
 206 {
 207         refcount_inc (&data->count);
 208 }
 209
 210 static void put_ep (struct ep_data *data)
 211 {
 212         if (likely (!refcount_dec_and_test (&data->count)))
 213                 return;
 214         put_dev (data->dev);
 215         /* needs no more cleanup */
 216         BUG_ON (!list_empty (&data->epfiles));
 217         BUG_ON (waitqueue_active (&data->wait));
 218         kfree (data);
 219 }
 220
 221 /*----------------------------------------------------------------------*/
 222
 223 /* most "how to use the hardware" policy choices are in userspace:
 224  * mapping endpoint roles (which the driver needs) to the capabilities
 225  * which the usb controller has.  most of those capabilities are exposed
 226  * implicitly, starting with the driver name and then endpoint names.
 227  */
 228
 229 static const char *CHIP;
 230
 231 /*----------------------------------------------------------------------*/
 232
 233 /* NOTE:  don't use dev_printk calls before binding to the gadget
 234  * at the end of ep0 configuration, or after unbind.
 235  */
 236
 237 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
 238 #define xprintk(d,level,fmt,args...) \
 239         printk(level "%s: " fmt , shortname , ## args)
 240
 241 #ifdef DEBUG
 242 #define DBG(dev,fmt,args...) \
 243         xprintk(dev , KERN_DEBUG , fmt , ## args)
 244 #else
 245 #define DBG(dev,fmt,args...) \
 246         do { } while (0)
 247 #endif /* DEBUG */
 248
 249 #ifdef VERBOSE_DEBUG
 250 #define VDEBUG  DBG
 251 #else
 252 #define VDEBUG(dev,fmt,args...) \
 253         do { } while (0)
 254 #endif /* DEBUG */
 255
 256 #define ERROR(dev,fmt,args...) \
 257         xprintk(dev , KERN_ERR , fmt , ## args)
 258 #define INFO(dev,fmt,args...) \
 259         xprintk(dev , KERN_INFO , fmt , ## args)
 260
 261
 262 /*----------------------------------------------------------------------*/
 263
 264 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
 265  *
 266  * After opening, configure non-control endpoints.  Then use normal
 267  * stream read() and write() requests; and maybe ioctl() to get more
 268  * precise FIFO status when recovering from cancellation.
 269  */
 270
 271 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
 272 {
 273         struct ep_data  *epdata = ep->driver_data;
 274
 275         if (!req->context)
 276                 return;
 277         if (req->status)
 278                 epdata->status = req->status;
 279         else
 280                 epdata->status = req->actual;
 281         complete ((struct completion *)req->context);
 282 }
 283
 284 /* tasklock endpoint, returning when it's connected.
 285  * still need dev->lock to use epdata->ep.
 286  */
 287 static int
 288 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
 289 {
 290         int     val;
 291
 292         if (f_flags & O_NONBLOCK) {
 293                 if (!mutex_trylock(&epdata->lock))
 294                         goto nonblock;
 295                 if (epdata->state != STATE_EP_ENABLED &&
 296                     (!is_write || epdata->state != STATE_EP_READY)) {
 297                         mutex_unlock(&epdata->lock);
 298 nonblock:
 299                         val = -EAGAIN;
 300                 } else
 301                         val = 0;
 302                 return val;
 303         }
 304
 305         val = mutex_lock_interruptible(&epdata->lock);
 306         if (val < 0)
 307                 return val;
 308
 309         switch (epdata->state) {
 310         case STATE_EP_ENABLED:
 311                 return 0;
 312         case STATE_EP_READY:                    /* not configured yet */
 313                 if (is_write)
 314                         return 0;
 315                 fallthrough;
 316         case STATE_EP_UNBOUND:                  /* clean disconnect */
 317                 break;
 318         // case STATE_EP_DISABLED:              /* "can't happen" */
 319         default:                                /* error! */
 320                 pr_debug ("%s: ep %p not available, state %d\n",
 321                                 shortname, epdata, epdata->state);
 322         }
 323         mutex_unlock(&epdata->lock);
 324         return -ENODEV;
 325 }
 326
 327 static ssize_t
 328 ep_io (struct ep_data *epdata, void *buf, unsigned len)
 329 {
 330         DECLARE_COMPLETION_ONSTACK (done);
 331         int value;
 332
 333         spin_lock_irq (&epdata->dev->lock);
 334         if (likely (epdata->ep != NULL)) {
 335                 struct usb_request      *req = epdata->req;
 336
 337                 req->context = &done;
 338                 req->complete = epio_complete;
 339                 req->buf = buf;
 340                 req->length = len;
 341                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
 342         } else
 343                 value = -ENODEV;
 344         spin_unlock_irq (&epdata->dev->lock);
 345
 346         if (likely (value == 0)) {
 347                 value = wait_for_completion_interruptible(&done);
 348                 if (value != 0) {
 349                         spin_lock_irq (&epdata->dev->lock);
 350                         if (likely (epdata->ep != NULL)) {
 351                                 DBG (epdata->dev, "%s i/o interrupted\n",
 352                                                 epdata->name);
 353                                 usb_ep_dequeue (epdata->ep, epdata->req);
 354                                 spin_unlock_irq (&epdata->dev->lock);
 355
 356                                 wait_for_completion(&done);
 357                                 if (epdata->status == -ECONNRESET)
 358                                         epdata->status = -EINTR;
 359                         } else {
 360                                 spin_unlock_irq (&epdata->dev->lock);
 361
 362                                 DBG (epdata->dev, "endpoint gone\n");
 363                                 epdata->status = -ENODEV;
 364                         }
 365                 }
 366                 return epdata->status;
 367         }
 368         return value;
 369 }
 370
 371 static int
 372 ep_release (struct inode *inode, struct file *fd)
 373 {
 374         struct ep_data          *data = fd->private_data;
 375         int value;
 376
 377         value = mutex_lock_interruptible(&data->lock);
 378         if (value < 0)
 379                 return value;
 380
 381         /* clean up if this can be reopened */
 382         if (data->state != STATE_EP_UNBOUND) {
 383                 data->state = STATE_EP_DISABLED;
 384                 data->desc.bDescriptorType = 0;
 385                 data->hs_desc.bDescriptorType = 0;
 386                 usb_ep_disable(data->ep);
 387         }
 388         mutex_unlock(&data->lock);
 389         put_ep (data);
 390         return 0;
 391 }
 392
 393 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
 394 {
 395         struct ep_data          *data = fd->private_data;
 396         int                     status;
 397
 398         if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
 399                 return status;
 400
 401         spin_lock_irq (&data->dev->lock);
 402         if (likely (data->ep != NULL)) {
 403                 switch (code) {
 404                 case GADGETFS_FIFO_STATUS:
 405                         status = usb_ep_fifo_status (data->ep);
 406                         break;
 407                 case GADGETFS_FIFO_FLUSH:
 408                         usb_ep_fifo_flush (data->ep);
 409                         break;
 410                 case GADGETFS_CLEAR_HALT:
 411                         status = usb_ep_clear_halt (data->ep);
 412                         break;
 413                 default:
 414                         status = -ENOTTY;
 415                 }
 416         } else
 417                 status = -ENODEV;
 418         spin_unlock_irq (&data->dev->lock);
 419         mutex_unlock(&data->lock);
 420         return status;
 421 }
 422
 423 /*----------------------------------------------------------------------*/
 424
 425 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
 426
 427 struct kiocb_priv {
 428         struct usb_request      *req;
 429         struct ep_data          *epdata;
 430         struct kiocb            *iocb;
 431         struct mm_struct        *mm;
 432         struct work_struct      work;
 433         void                    *buf;
 434         struct iov_iter         to;
 435         const void              *to_free;
 436         unsigned                actual;
 437 };
 438
 439 static int ep_aio_cancel(struct kiocb *iocb)
 440 {
 441         struct kiocb_priv       *priv = iocb->private;
 442         struct ep_data          *epdata;
 443         int                     value;
 444
 445         local_irq_disable();
 446         epdata = priv->epdata;
 447         // spin_lock(&epdata->dev->lock);
 448         if (likely(epdata && epdata->ep && priv->req))
 449                 value = usb_ep_dequeue (epdata->ep, priv->req);
 450         else
 451                 value = -EINVAL;
 452         // spin_unlock(&epdata->dev->lock);
 453         local_irq_enable();
 454
 455         return value;
 456 }
 457
 458 static void ep_user_copy_worker(struct work_struct *work)
 459 {
 460         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
 461         struct mm_struct *mm = priv->mm;
 462         struct kiocb *iocb = priv->iocb;
 463         size_t ret;
 464
 465         kthread_use_mm(mm);
 466         ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
 467         kthread_unuse_mm(mm);
 468         if (!ret)
 469                 ret = -EFAULT;
 470
 471         /* completing the iocb can drop the ctx and mm, don't touch mm after */
 472         iocb->ki_complete(iocb, ret, ret);
 473
 474         kfree(priv->buf);
 475         kfree(priv->to_free);
 476         kfree(priv);
 477 }
 478
 479 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 480 {
 481         struct kiocb            *iocb = req->context;
 482         struct kiocb_priv       *priv = iocb->private;
 483         struct ep_data          *epdata = priv->epdata;
 484
 485         /* lock against disconnect (and ideally, cancel) */
 486         spin_lock(&epdata->dev->lock);
 487         priv->req = NULL;
 488         priv->epdata = NULL;
 489
 490         /* if this was a write or a read returning no data then we
 491          * don't need to copy anything to userspace, so we can
 492          * complete the aio request immediately.
 493          */
 494         if (priv->to_free == NULL || unlikely(req->actual == 0)) {
 495                 kfree(req->buf);
 496                 kfree(priv->to_free);
 497                 kfree(priv);
 498                 iocb->private = NULL;
 499                 /* aio_complete() reports bytes-transferred _and_ faults */
 500
 501                 iocb->ki_complete(iocb,
 502                                 req->actual ? req->actual : (long)req->status,
 503                                 req->status);
 504         } else {
 505                 /* ep_copy_to_user() won't report both; we hide some faults */
 506                 if (unlikely(0 != req->status))
 507                         DBG(epdata->dev, "%s fault %d len %d\n",
 508                                 ep->name, req->status, req->actual);
 509
 510                 priv->buf = req->buf;
 511                 priv->actual = req->actual;
 512                 INIT_WORK(&priv->work, ep_user_copy_worker);
 513                 schedule_work(&priv->work);
 514         }
 515
 516         usb_ep_free_request(ep, req);
 517         spin_unlock(&epdata->dev->lock);
 518         put_ep(epdata);
 519 }
 520
 521 static ssize_t ep_aio(struct kiocb *iocb,
 522                       struct kiocb_priv *priv,
 523                       struct ep_data *epdata,
 524                       char *buf,
 525                       size_t len)
 526 {
 527         struct usb_request *req;
 528         ssize_t value;
 529
 530         iocb->private = priv;
 531         priv->iocb = iocb;
 532
 533         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
 534         get_ep(epdata);
 535         priv->epdata = epdata;
 536         priv->actual = 0;
 537         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
 538
 539         /* each kiocb is coupled to one usb_request, but we can't
 540          * allocate or submit those if the host disconnected.
 541          */
 542         spin_lock_irq(&epdata->dev->lock);
 543         value = -ENODEV;
 544         if (unlikely(epdata->ep == NULL))
 545                 goto fail;
 546
 547         req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
 548         value = -ENOMEM;
 549         if (unlikely(!req))
 550                 goto fail;
 551
 552         priv->req = req;
 553         req->buf = buf;
 554         req->length = len;
 555         req->complete = ep_aio_complete;
 556         req->context = iocb;
 557         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
 558         if (unlikely(0 != value)) {
 559                 usb_ep_free_request(epdata->ep, req);
 560                 goto fail;
 561         }
 562         spin_unlock_irq(&epdata->dev->lock);
 563         return -EIOCBQUEUED;
 564
 565 fail:
 566         spin_unlock_irq(&epdata->dev->lock);
 567         kfree(priv->to_free);
 568         kfree(priv);
 569         put_ep(epdata);
 570         return value;
 571 }
 572
 573 static ssize_t
 574 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
 575 {
 576         struct file *file = iocb->ki_filp;
 577         struct ep_data *epdata = file->private_data;
 578         size_t len = iov_iter_count(to);
 579         ssize_t value;
 580         char *buf;
 581
 582         if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
 583                 return value;
 584
 585         /* halt any endpoint by doing a "wrong direction" i/o call */
 586         if (usb_endpoint_dir_in(&epdata->desc)) {
 587                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 588                     !is_sync_kiocb(iocb)) {
 589                         mutex_unlock(&epdata->lock);
 590                         return -EINVAL;
 591                 }
 592                 DBG (epdata->dev, "%s halt\n", epdata->name);
 593                 spin_lock_irq(&epdata->dev->lock);
 594                 if (likely(epdata->ep != NULL))
 595                         usb_ep_set_halt(epdata->ep);
 596                 spin_unlock_irq(&epdata->dev->lock);
 597                 mutex_unlock(&epdata->lock);
 598                 return -EBADMSG;
 599         }
 600
 601         buf = kmalloc(len, GFP_KERNEL);
 602         if (unlikely(!buf)) {
 603                 mutex_unlock(&epdata->lock);
 604                 return -ENOMEM;
 605         }
 606         if (is_sync_kiocb(iocb)) {
 607                 value = ep_io(epdata, buf, len);
 608                 if (value >= 0 && (copy_to_iter(buf, value, to) != value))
 609                         value = -EFAULT;
 610         } else {
 611                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 612                 value = -ENOMEM;
 613                 if (!priv)
 614                         goto fail;
 615                 priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
 616                 if (!priv->to_free) {
 617                         kfree(priv);
 618                         goto fail;
 619                 }
 620                 value = ep_aio(iocb, priv, epdata, buf, len);
 621                 if (value == -EIOCBQUEUED)
 622                         buf = NULL;
 623         }
 624 fail:
 625         kfree(buf);
 626         mutex_unlock(&epdata->lock);
 627         return value;
 628 }
 629
 630 static ssize_t ep_config(struct ep_data *, const char *, size_t);
 631
 632 static ssize_t
 633 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
 634 {
 635         struct file *file = iocb->ki_filp;
 636         struct ep_data *epdata = file->private_data;
 637         size_t len = iov_iter_count(from);
 638         bool configured;
 639         ssize_t value;
 640         char *buf;
 641
 642         if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
 643                 return value;
 644
 645         configured = epdata->state == STATE_EP_ENABLED;
 646
 647         /* halt any endpoint by doing a "wrong direction" i/o call */
 648         if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
 649                 if (usb_endpoint_xfer_isoc(&epdata->desc) ||
 650                     !is_sync_kiocb(iocb)) {
 651                         mutex_unlock(&epdata->lock);
 652                         return -EINVAL;
 653                 }
 654                 DBG (epdata->dev, "%s halt\n", epdata->name);
 655                 spin_lock_irq(&epdata->dev->lock);
 656                 if (likely(epdata->ep != NULL))
 657                         usb_ep_set_halt(epdata->ep);
 658                 spin_unlock_irq(&epdata->dev->lock);
 659                 mutex_unlock(&epdata->lock);
 660                 return -EBADMSG;
 661         }
 662
 663         buf = kmalloc(len, GFP_KERNEL);
 664         if (unlikely(!buf)) {
 665                 mutex_unlock(&epdata->lock);
 666                 return -ENOMEM;
 667         }
 668
 669         if (unlikely(!copy_from_iter_full(buf, len, from))) {
 670                 value = -EFAULT;
 671                 goto out;
 672         }
 673
 674         if (unlikely(!configured)) {
 675                 value = ep_config(epdata, buf, len);
 676         } else if (is_sync_kiocb(iocb)) {
 677                 value = ep_io(epdata, buf, len);
 678         } else {
 679                 struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
 680                 value = -ENOMEM;
 681                 if (priv) {
 682                         value = ep_aio(iocb, priv, epdata, buf, len);
 683                         if (value == -EIOCBQUEUED)
 684                                 buf = NULL;
 685                 }
 686         }
 687 out:
 688         kfree(buf);
 689         mutex_unlock(&epdata->lock);
 690         return value;
 691 }
 692
 693 /*----------------------------------------------------------------------*/
 694
 695 /* used after endpoint configuration */
 696 static const struct file_operations ep_io_operations = {
 697         .owner =        THIS_MODULE,
 698
 699         .open =         ep_open,
 700         .release =      ep_release,
 701         .llseek =       no_llseek,
 702         .unlocked_ioctl = ep_ioctl,
 703         .read_iter =    ep_read_iter,
 704         .write_iter =   ep_write_iter,
 705 };
 706
 707 /* ENDPOINT INITIALIZATION
 708  *
 709  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
 710  *     status = write (fd, descriptors, sizeof descriptors)
 711  *
 712  * That write establishes the endpoint configuration, configuring
 713  * the controller to process bulk, interrupt, or isochronous transfers
 714  * at the right maxpacket size, and so on.
 715  *
 716  * The descriptors are message type 1, identified by a host order u32
 717  * at the beginning of what's written.  Descriptor order is: full/low
 718  * speed descriptor, then optional high speed descriptor.
 719  */
 720 static ssize_t
 721 ep_config (struct ep_data *data, const char *buf, size_t len)
 722 {
 723         struct usb_ep           *ep;
 724         u32                     tag;
 725         int                     value, length = len;
 726
 727         if (data->state != STATE_EP_READY) {
 728                 value = -EL2HLT;
 729                 goto fail;
 730         }
 731
 732         value = len;
 733         if (len < USB_DT_ENDPOINT_SIZE + 4)
 734                 goto fail0;
 735
 736         /* we might need to change message format someday */
 737         memcpy(&tag, buf, 4);
 738         if (tag != 1) {
 739                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
 740                 goto fail0;
 741         }
 742         buf += 4;
 743         len -= 4;
 744
 745         /* NOTE:  audio endpoint extensions not accepted here;
 746          * just don't include the extra bytes.
 747          */
 748
 749         /* full/low speed descriptor, then high speed */
 750         memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
 751         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
 752                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
 753                 goto fail0;
 754         if (len != USB_DT_ENDPOINT_SIZE) {
 755                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
 756                         goto fail0;
 757                 memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
 758                         USB_DT_ENDPOINT_SIZE);
 759                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
 760                                 || data->hs_desc.bDescriptorType
 761                                         != USB_DT_ENDPOINT) {
 762                         DBG(data->dev, "config %s, bad hs length or type\n",
 763                                         data->name);
 764                         goto fail0;
 765                 }
 766         }
 767
 768         spin_lock_irq (&data->dev->lock);
 769         if (data->dev->state == STATE_DEV_UNBOUND) {
 770                 value = -ENOENT;
 771                 goto gone;
 772         } else {
 773                 ep = data->ep;
 774                 if (ep == NULL) {
 775                         value = -ENODEV;
 776                         goto gone;
 777                 }
 778         }
 779         switch (data->dev->gadget->speed) {
 780         case USB_SPEED_LOW:
 781         case USB_SPEED_FULL:
 782                 ep->desc = &data->desc;
 783                 break;
 784         case USB_SPEED_HIGH:
 785                 /* fails if caller didn't provide that descriptor... */
 786                 ep->desc = &data->hs_desc;
 787                 break;
 788         default:
 789                 DBG(data->dev, "unconnected, %s init abandoned\n",
 790                                 data->name);
 791                 value = -EINVAL;
 792                 goto gone;
 793         }
 794         value = usb_ep_enable(ep);
 795         if (value == 0) {
 796                 data->state = STATE_EP_ENABLED;
 797                 value = length;
 798         }
 799 gone:
 800         spin_unlock_irq (&data->dev->lock);
 801         if (value < 0) {
 802 fail:
 803                 data->desc.bDescriptorType = 0;
 804                 data->hs_desc.bDescriptorType = 0;
 805         }
 806         return value;
 807 fail0:
 808         value = -EINVAL;
 809         goto fail;
 810 }
 811
 812 static int
 813 ep_open (struct inode *inode, struct file *fd)
 814 {
 815         struct ep_data          *data = inode->i_private;
 816         int                     value = -EBUSY;
 817
 818         if (mutex_lock_interruptible(&data->lock) != 0)
 819                 return -EINTR;
 820         spin_lock_irq (&data->dev->lock);
 821         if (data->dev->state == STATE_DEV_UNBOUND)
 822                 value = -ENOENT;
 823         else if (data->state == STATE_EP_DISABLED) {
 824                 value = 0;
 825                 data->state = STATE_EP_READY;
 826                 get_ep (data);
 827                 fd->private_data = data;
 828                 VDEBUG (data->dev, "%s ready\n", data->name);
 829         } else
 830                 DBG (data->dev, "%s state %d\n",
 831                         data->name, data->state);
 832         spin_unlock_irq (&data->dev->lock);
 833         mutex_unlock(&data->lock);
 834         return value;
 835 }
 836
 837 /*----------------------------------------------------------------------*/
 838
 839 /* EP0 IMPLEMENTATION can be partly in userspace.
 840  *
 841  * Drivers that use this facility receive various events, including
 842  * control requests the kernel doesn't handle.  Drivers that don't
 843  * use this facility may be too simple-minded for real applications.
 844  */
 845
 846 static inline void ep0_readable (struct dev_data *dev)
 847 {
 848         wake_up (&dev->wait);
 849         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
 850 }
 851
 852 static void clean_req (struct usb_ep *ep, struct usb_request *req)
 853 {
 854         struct dev_data         *dev = ep->driver_data;
 855
 856         if (req->buf != dev->rbuf) {
 857                 kfree(req->buf);
 858                 req->buf = dev->rbuf;
 859         }
 860         req->complete = epio_complete;
 861         dev->setup_out_ready = 0;
 862 }
 863
 864 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
 865 {
 866         struct dev_data         *dev = ep->driver_data;
 867         unsigned long           flags;
 868         int                     free = 1;
 869
 870         /* for control OUT, data must still get to userspace */
 871         spin_lock_irqsave(&dev->lock, flags);
 872         if (!dev->setup_in) {
 873                 dev->setup_out_error = (req->status != 0);
 874                 if (!dev->setup_out_error)
 875                         free = 0;
 876                 dev->setup_out_ready = 1;
 877                 ep0_readable (dev);
 878         }
 879
 880         /* clean up as appropriate */
 881         if (free && req->buf != &dev->rbuf)
 882                 clean_req (ep, req);
 883         req->complete = epio_complete;
 884         spin_unlock_irqrestore(&dev->lock, flags);
 885 }
 886
 887 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 888 {
 889         struct dev_data *dev = ep->driver_data;
 890
 891         if (dev->setup_out_ready) {
 892                 DBG (dev, "ep0 request busy!\n");
 893                 return -EBUSY;
 894         }
 895         if (len > sizeof (dev->rbuf))
 896                 req->buf = kmalloc(len, GFP_ATOMIC);
 897         if (req->buf == NULL) {
 898                 req->buf = dev->rbuf;
 899                 return -ENOMEM;
 900         }
 901         req->complete = ep0_complete;
 902         req->length = len;
 903         req->zero = 0;
 904         return 0;
 905 }
 906
 907 static ssize_t
 908 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 909 {
 910         struct dev_data                 *dev = fd->private_data;
 911         ssize_t                         retval;
 912         enum ep0_state                  state;
 913
 914         spin_lock_irq (&dev->lock);
 915         if (dev->state <= STATE_DEV_OPENED) {
 916                 retval = -EINVAL;
 917                 goto done;
 918         }
 919
 920         /* report fd mode change before acting on it */
 921         if (dev->setup_abort) {
 922                 dev->setup_abort = 0;
 923                 retval = -EIDRM;
 924                 goto done;
 925         }
 926
 927         /* control DATA stage */
 928         if ((state = dev->state) == STATE_DEV_SETUP) {
 929
 930                 if (dev->setup_in) {            /* stall IN */
 931                         VDEBUG(dev, "ep0in stall\n");
 932                         (void) usb_ep_set_halt (dev->gadget->ep0);
 933                         retval = -EL2HLT;
 934                         dev->state = STATE_DEV_CONNECTED;
 935
 936                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
 937                         struct usb_ep           *ep = dev->gadget->ep0;
 938                         struct usb_request      *req = dev->req;
 939
 940                         if ((retval = setup_req (ep, req, 0)) == 0) {
 941                                 ++dev->udc_usage;
 942                                 spin_unlock_irq (&dev->lock);
 943                                 retval = usb_ep_queue (ep, req, GFP_KERNEL);
 944                                 spin_lock_irq (&dev->lock);
 945                                 --dev->udc_usage;
 946                         }
 947                         dev->state = STATE_DEV_CONNECTED;
 948
 949                         /* assume that was SET_CONFIGURATION */
 950                         if (dev->current_config) {
 951                                 unsigned power;
 952
 953                                 if (gadget_is_dualspeed(dev->gadget)
 954                                                 && (dev->gadget->speed
 955                                                         == USB_SPEED_HIGH))
 956                                         power = dev->hs_config->bMaxPower;
 957                                 else
 958                                         power = dev->config->bMaxPower;
 959                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
 960                         }
 961
 962                 } else {                        /* collect OUT data */
 963                         if ((fd->f_flags & O_NONBLOCK) != 0
 964                                         && !dev->setup_out_ready) {
 965                                 retval = -EAGAIN;
 966                                 goto done;
 967                         }
 968                         spin_unlock_irq (&dev->lock);
 969                         retval = wait_event_interruptible (dev->wait,
 970                                         dev->setup_out_ready != 0);
 971
 972                         /* FIXME state could change from under us */
 973                         spin_lock_irq (&dev->lock);
 974                         if (retval)
 975                                 goto done;
 976
 977                         if (dev->state != STATE_DEV_SETUP) {
 978                                 retval = -ECANCELED;
 979                                 goto done;
 980                         }
 981                         dev->state = STATE_DEV_CONNECTED;
 982
 983                         if (dev->setup_out_error)
 984                                 retval = -EIO;
 985                         else {
 986                                 len = min (len, (size_t)dev->req->actual);
 987                                 ++dev->udc_usage;
 988                                 spin_unlock_irq(&dev->lock);
 989                                 if (copy_to_user (buf, dev->req->buf, len))
 990                                         retval = -EFAULT;
 991                                 else
 992                                         retval = len;
 993                                 spin_lock_irq(&dev->lock);
 994                                 --dev->udc_usage;
 995                                 clean_req (dev->gadget->ep0, dev->req);
 996                                 /* NOTE userspace can't yet choose to stall */
 997                         }
 998                 }
 999                 goto done;
1000         }
1001
1002         /* else normal: return event data */
1003         if (len < sizeof dev->event [0]) {
1004                 retval = -EINVAL;
1005                 goto done;
1006         }
1007         len -= len % sizeof (struct usb_gadgetfs_event);
1008         dev->usermode_setup = 1;
1009
1010 scan:
1011         /* return queued events right away */
1012         if (dev->ev_next != 0) {
1013                 unsigned                i, n;
1014
1015                 n = len / sizeof (struct usb_gadgetfs_event);
1016                 if (dev->ev_next < n)
1017                         n = dev->ev_next;
1018
1019                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1020                 for (i = 0; i < n; i++) {
1021                         if (dev->event [i].type == GADGETFS_SETUP) {
1022                                 dev->state = STATE_DEV_SETUP;
1023                                 n = i + 1;
1024                                 break;
1025                         }
1026                 }
1027                 spin_unlock_irq (&dev->lock);
1028                 len = n * sizeof (struct usb_gadgetfs_event);
1029                 if (copy_to_user (buf, &dev->event, len))
1030                         retval = -EFAULT;
1031                 else
1032                         retval = len;
1033                 if (len > 0) {
1034                         /* NOTE this doesn't guard against broken drivers;
1035                          * concurrent ep0 readers may lose events.
1036                          */
1037                         spin_lock_irq (&dev->lock);
1038                         if (dev->ev_next > n) {
1039                                 memmove(&dev->event[0], &dev->event[n],
1040                                         sizeof (struct usb_gadgetfs_event)
1041                                                 * (dev->ev_next - n));
1042                         }
1043                         dev->ev_next -= n;
1044                         spin_unlock_irq (&dev->lock);
1045                 }
1046                 return retval;
1047         }
1048         if (fd->f_flags & O_NONBLOCK) {
1049                 retval = -EAGAIN;
1050                 goto done;
1051         }
1052
1053         switch (state) {
1054         default:
1055                 DBG (dev, "fail %s, state %d\n", __func__, state);
1056                 retval = -ESRCH;
1057                 break;
1058         case STATE_DEV_UNCONNECTED:
1059         case STATE_DEV_CONNECTED:
1060                 spin_unlock_irq (&dev->lock);
1061                 DBG (dev, "%s wait\n", __func__);
1062
1063                 /* wait for events */
1064                 retval = wait_event_interruptible (dev->wait,
1065                                 dev->ev_next != 0);
1066                 if (retval < 0)
1067                         return retval;
1068                 spin_lock_irq (&dev->lock);
1069                 goto scan;
1070         }
1071
1072 done:
1073         spin_unlock_irq (&dev->lock);
1074         return retval;
1075 }
1076
1077 static struct usb_gadgetfs_event *
1078 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1079 {
1080         struct usb_gadgetfs_event       *event;
1081         unsigned                        i;
1082
1083         switch (type) {
1084         /* these events purge the queue */
1085         case GADGETFS_DISCONNECT:
1086                 if (dev->state == STATE_DEV_SETUP)
1087                         dev->setup_abort = 1;
1088                 fallthrough;
1089         case GADGETFS_CONNECT:
1090                 dev->ev_next = 0;
1091                 break;
1092         case GADGETFS_SETUP:            /* previous request timed out */
1093         case GADGETFS_SUSPEND:          /* same effect */
1094                 /* these events can't be repeated */
1095                 for (i = 0; i != dev->ev_next; i++) {
1096                         if (dev->event [i].type != type)
1097                                 continue;
1098                         DBG(dev, "discard old event[%d] %d\n", i, type);
1099                         dev->ev_next--;
1100                         if (i == dev->ev_next)
1101                                 break;
1102                         /* indices start at zero, for simplicity */
1103                         memmove (&dev->event [i], &dev->event [i + 1],
1104                                 sizeof (struct usb_gadgetfs_event)
1105                                         * (dev->ev_next - i));
1106                 }
1107                 break;
1108         default:
1109                 BUG ();
1110         }
1111         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1112         event = &dev->event [dev->ev_next++];
1113         BUG_ON (dev->ev_next > N_EVENT);
1114         memset (event, 0, sizeof *event);
1115         event->type = type;
1116         return event;
1117 }
1118
1119 static ssize_t
1120 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1121 {
1122         struct dev_data         *dev = fd->private_data;
1123         ssize_t                 retval = -ESRCH;
1124
1125         /* report fd mode change before acting on it */
1126         if (dev->setup_abort) {
1127                 dev->setup_abort = 0;
1128                 retval = -EIDRM;
1129
1130         /* data and/or status stage for control request */
1131         } else if (dev->state == STATE_DEV_SETUP) {
1132
1133                 len = min_t(size_t, len, dev->setup_wLength);
1134                 if (dev->setup_in) {
1135                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1136                         if (retval == 0) {
1137                                 dev->state = STATE_DEV_CONNECTED;
1138                                 ++dev->udc_usage;
1139                                 spin_unlock_irq (&dev->lock);
1140                                 if (copy_from_user (dev->req->buf, buf, len))
1141                                         retval = -EFAULT;
1142                                 else {
1143                                         if (len < dev->setup_wLength)
1144                                                 dev->req->zero = 1;
1145                                         retval = usb_ep_queue (
1146                                                 dev->gadget->ep0, dev->req,
1147                                                 GFP_KERNEL);
1148                                 }
1149                                 spin_lock_irq(&dev->lock);
1150                                 --dev->udc_usage;
1151                                 if (retval < 0) {
1152                                         clean_req (dev->gadget->ep0, dev->req);
1153                                 } else
1154                                         retval = len;
1155
1156                                 return retval;
1157                         }
1158
1159                 /* can stall some OUT transfers */
1160                 } else if (dev->setup_can_stall) {
1161                         VDEBUG(dev, "ep0out stall\n");
1162                         (void) usb_ep_set_halt (dev->gadget->ep0);
1163                         retval = -EL2HLT;
1164                         dev->state = STATE_DEV_CONNECTED;
1165                 } else {
1166                         DBG(dev, "bogus ep0out stall!\n");
1167                 }
1168         } else
1169                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1170
1171         return retval;
1172 }
1173
1174 static int
1175 ep0_fasync (int f, struct file *fd, int on)
1176 {
1177         struct dev_data         *dev = fd->private_data;
1178         // caller must F_SETOWN before signal delivery happens
1179         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1180         return fasync_helper (f, fd, on, &dev->fasync);
1181 }
1182
1183 static struct usb_gadget_driver gadgetfs_driver;
1184
1185 static int
1186 dev_release (struct inode *inode, struct file *fd)
1187 {
1188         struct dev_data         *dev = fd->private_data;
1189
1190         /* closing ep0 === shutdown all */
1191
1192         if (dev->gadget_registered) {
1193                 usb_gadget_unregister_driver (&gadgetfs_driver);
1194                 dev->gadget_registered = false;
1195         }
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 __poll_t
1215 ep0_poll (struct file *fd, poll_table *wait)
1216 {
1217        struct dev_data         *dev = fd->private_data;
1218        __poll_t                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 = EPOLLHUP;
1231                 goto out;
1232         }
1233
1234         if (dev->state == STATE_DEV_SETUP) {
1235                 if (dev->setup_in || dev->setup_can_stall)
1236                         mask = EPOLLOUT;
1237         } else {
1238                 if (dev->ev_next != 0)
1239                         mask = EPOLLIN;
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         spin_lock (&dev->lock);
1338         dev->setup_abort = 0;
1339         if (dev->state == STATE_DEV_UNCONNECTED) {
1340                 if (gadget_is_dualspeed(gadget)
1341                                 && gadget->speed == USB_SPEED_HIGH
1342                                 && dev->hs_config == NULL) {
1343                         spin_unlock(&dev->lock);
1344                         ERROR (dev, "no high speed config??\n");
1345                         return -EINVAL;
1346                 }
1347
1348                 dev->state = STATE_DEV_CONNECTED;
1349
1350                 INFO (dev, "connected\n");
1351                 event = next_event (dev, GADGETFS_CONNECT);
1352                 event->u.speed = gadget->speed;
1353                 ep0_readable (dev);
1354
1355         /* host may have given up waiting for response.  we can miss control
1356          * requests handled lower down (device/endpoint status and features);
1357          * then ep0_{read,write} will report the wrong status. controller
1358          * driver will have aborted pending i/o.
1359          */
1360         } else if (dev->state == STATE_DEV_SETUP)
1361                 dev->setup_abort = 1;
1362
1363         req->buf = dev->rbuf;
1364         req->context = NULL;
1365         switch (ctrl->bRequest) {
1366
1367         case USB_REQ_GET_DESCRIPTOR:
1368                 if (ctrl->bRequestType != USB_DIR_IN)
1369                         goto unrecognized;
1370                 switch (w_value >> 8) {
1371
1372                 case USB_DT_DEVICE:
1373                         value = min (w_length, (u16) sizeof *dev->dev);
1374                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1375                         req->buf = dev->dev;
1376                         break;
1377                 case USB_DT_DEVICE_QUALIFIER:
1378                         if (!dev->hs_config)
1379                                 break;
1380                         value = min (w_length, (u16)
1381                                 sizeof (struct usb_qualifier_descriptor));
1382                         make_qualifier (dev);
1383                         break;
1384                 case USB_DT_OTHER_SPEED_CONFIG:
1385                 case USB_DT_CONFIG:
1386                         value = config_buf (dev,
1387                                         w_value >> 8,
1388                                         w_value & 0xff);
1389                         if (value >= 0)
1390                                 value = min (w_length, (u16) value);
1391                         break;
1392                 case USB_DT_STRING:
1393                         goto unrecognized;
1394
1395                 default:                // all others are errors
1396                         break;
1397                 }
1398                 break;
1399
1400         /* currently one config, two speeds */
1401         case USB_REQ_SET_CONFIGURATION:
1402                 if (ctrl->bRequestType != 0)
1403                         goto unrecognized;
1404                 if (0 == (u8) w_value) {
1405                         value = 0;
1406                         dev->current_config = 0;
1407                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1408                         // user mode expected to disable endpoints
1409                 } else {
1410                         u8      config, power;
1411
1412                         if (gadget_is_dualspeed(gadget)
1413                                         && gadget->speed == USB_SPEED_HIGH) {
1414                                 config = dev->hs_config->bConfigurationValue;
1415                                 power = dev->hs_config->bMaxPower;
1416                         } else {
1417                                 config = dev->config->bConfigurationValue;
1418                                 power = dev->config->bMaxPower;
1419                         }
1420
1421                         if (config == (u8) w_value) {
1422                                 value = 0;
1423                                 dev->current_config = config;
1424                                 usb_gadget_vbus_draw(gadget, 2 * power);
1425                         }
1426                 }
1427
1428                 /* report SET_CONFIGURATION like any other control request,
1429                  * except that usermode may not stall this.  the next
1430                  * request mustn't be allowed start until this finishes:
1431                  * endpoints and threads set up, etc.
1432                  *
1433                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1434                  * has bad/racey automagic that prevents synchronizing here.
1435                  * even kernel mode drivers often miss them.
1436                  */
1437                 if (value == 0) {
1438                         INFO (dev, "configuration #%d\n", dev->current_config);
1439                         usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1440                         if (dev->usermode_setup) {
1441                                 dev->setup_can_stall = 0;
1442                                 goto delegate;
1443                         }
1444                 }
1445                 break;
1446
1447 #ifndef CONFIG_USB_PXA25X
1448         /* PXA automagically handles this request too */
1449         case USB_REQ_GET_CONFIGURATION:
1450                 if (ctrl->bRequestType != 0x80)
1451                         goto unrecognized;
1452                 *(u8 *)req->buf = dev->current_config;
1453                 value = min (w_length, (u16) 1);
1454                 break;
1455 #endif
1456
1457         default:
1458 unrecognized:
1459                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1460                         dev->usermode_setup ? "delegate" : "fail",
1461                         ctrl->bRequestType, ctrl->bRequest,
1462                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1463
1464                 /* if there's an ep0 reader, don't stall */
1465                 if (dev->usermode_setup) {
1466                         dev->setup_can_stall = 1;
1467 delegate:
1468                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1469                                                 ? 1 : 0;
1470                         dev->setup_wLength = w_length;
1471                         dev->setup_out_ready = 0;
1472                         dev->setup_out_error = 0;
1473
1474                         /* read DATA stage for OUT right away */
1475                         if (unlikely (!dev->setup_in && w_length)) {
1476                                 value = setup_req (gadget->ep0, dev->req,
1477                                                         w_length);
1478                                 if (value < 0)
1479                                         break;
1480
1481                                 ++dev->udc_usage;
1482                                 spin_unlock (&dev->lock);
1483                                 value = usb_ep_queue (gadget->ep0, dev->req,
1484                                                         GFP_KERNEL);
1485                                 spin_lock (&dev->lock);
1486                                 --dev->udc_usage;
1487                                 if (value < 0) {
1488                                         clean_req (gadget->ep0, dev->req);
1489                                         break;
1490                                 }
1491
1492                                 /* we can't currently stall these */
1493                                 dev->setup_can_stall = 0;
1494                         }
1495
1496                         /* state changes when reader collects event */
1497                         event = next_event (dev, GADGETFS_SETUP);
1498                         event->u.setup = *ctrl;
1499                         ep0_readable (dev);
1500                         spin_unlock (&dev->lock);
1501                         return 0;
1502                 }
1503         }
1504
1505         /* proceed with data transfer and status phases? */
1506         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1507                 req->length = value;
1508                 req->zero = value < w_length;
1509
1510                 ++dev->udc_usage;
1511                 spin_unlock (&dev->lock);
1512                 value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1513                 spin_lock(&dev->lock);
1514                 --dev->udc_usage;
1515                 spin_unlock(&dev->lock);
1516                 if (value < 0) {
1517                         DBG (dev, "ep_queue --> %d\n", value);
1518                         req->status = 0;
1519                 }
1520                 return value;
1521         }
1522
1523         /* device stalls when value < 0 */
1524         spin_unlock (&dev->lock);
1525         return value;
1526 }
1527
1528 static void destroy_ep_files (struct dev_data *dev)
1529 {
1530         DBG (dev, "%s %d\n", __func__, dev->state);
1531
1532         /* dev->state must prevent interference */
1533         spin_lock_irq (&dev->lock);
1534         while (!list_empty(&dev->epfiles)) {
1535                 struct ep_data  *ep;
1536                 struct inode    *parent;
1537                 struct dentry   *dentry;
1538
1539                 /* break link to FS */
1540                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1541                 list_del_init (&ep->epfiles);
1542                 spin_unlock_irq (&dev->lock);
1543
1544                 dentry = ep->dentry;
1545                 ep->dentry = NULL;
1546                 parent = d_inode(dentry->d_parent);
1547
1548                 /* break link to controller */
1549                 mutex_lock(&ep->lock);
1550                 if (ep->state == STATE_EP_ENABLED)
1551                         (void) usb_ep_disable (ep->ep);
1552                 ep->state = STATE_EP_UNBOUND;
1553                 usb_ep_free_request (ep->ep, ep->req);
1554                 ep->ep = NULL;
1555                 mutex_unlock(&ep->lock);
1556
1557                 wake_up (&ep->wait);
1558                 put_ep (ep);
1559
1560                 /* break link to dcache */
1561                 inode_lock(parent);
1562                 d_delete (dentry);
1563                 dput (dentry);
1564                 inode_unlock(parent);
1565
1566                 spin_lock_irq (&dev->lock);
1567         }
1568         spin_unlock_irq (&dev->lock);
1569 }
1570
1571
1572 static struct dentry *
1573 gadgetfs_create_file (struct super_block *sb, char const *name,
1574                 void *data, const struct file_operations *fops);
1575
1576 static int activate_ep_files (struct dev_data *dev)
1577 {
1578         struct usb_ep   *ep;
1579         struct ep_data  *data;
1580
1581         gadget_for_each_ep (ep, dev->gadget) {
1582
1583                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1584                 if (!data)
1585                         goto enomem0;
1586                 data->state = STATE_EP_DISABLED;
1587                 mutex_init(&data->lock);
1588                 init_waitqueue_head (&data->wait);
1589
1590                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1591                 refcount_set (&data->count, 1);
1592                 data->dev = dev;
1593                 get_dev (dev);
1594
1595                 data->ep = ep;
1596                 ep->driver_data = data;
1597
1598                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1599                 if (!data->req)
1600                         goto enomem1;
1601
1602                 data->dentry = gadgetfs_create_file (dev->sb, data->name,
1603                                 data, &ep_io_operations);
1604                 if (!data->dentry)
1605                         goto enomem2;
1606                 list_add_tail (&data->epfiles, &dev->epfiles);
1607         }
1608         return 0;
1609
1610 enomem2:
1611         usb_ep_free_request (ep, data->req);
1612 enomem1:
1613         put_dev (dev);
1614         kfree (data);
1615 enomem0:
1616         DBG (dev, "%s enomem\n", __func__);
1617         destroy_ep_files (dev);
1618         return -ENOMEM;
1619 }
1620
1621 static void
1622 gadgetfs_unbind (struct usb_gadget *gadget)
1623 {
1624         struct dev_data         *dev = get_gadget_data (gadget);
1625
1626         DBG (dev, "%s\n", __func__);
1627
1628         spin_lock_irq (&dev->lock);
1629         dev->state = STATE_DEV_UNBOUND;
1630         while (dev->udc_usage > 0) {
1631                 spin_unlock_irq(&dev->lock);
1632                 usleep_range(1000, 2000);
1633                 spin_lock_irq(&dev->lock);
1634         }
1635         spin_unlock_irq (&dev->lock);
1636
1637         destroy_ep_files (dev);
1638         gadget->ep0->driver_data = NULL;
1639         set_gadget_data (gadget, NULL);
1640
1641         /* we've already been disconnected ... no i/o is active */
1642         if (dev->req)
1643                 usb_ep_free_request (gadget->ep0, dev->req);
1644         DBG (dev, "%s done\n", __func__);
1645         put_dev (dev);
1646 }
1647
1648 static struct dev_data          *the_device;
1649
1650 static int gadgetfs_bind(struct usb_gadget *gadget,
1651                 struct usb_gadget_driver *driver)
1652 {
1653         struct dev_data         *dev = the_device;
1654
1655         if (!dev)
1656                 return -ESRCH;
1657         if (0 != strcmp (CHIP, gadget->name)) {
1658                 pr_err("%s expected %s controller not %s\n",
1659                         shortname, CHIP, gadget->name);
1660                 return -ENODEV;
1661         }
1662
1663         set_gadget_data (gadget, dev);
1664         dev->gadget = gadget;
1665         gadget->ep0->driver_data = dev;
1666
1667         /* preallocate control response and buffer */
1668         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1669         if (!dev->req)
1670                 goto enomem;
1671         dev->req->context = NULL;
1672         dev->req->complete = epio_complete;
1673
1674         if (activate_ep_files (dev) < 0)
1675                 goto enomem;
1676
1677         INFO (dev, "bound to %s driver\n", gadget->name);
1678         spin_lock_irq(&dev->lock);
1679         dev->state = STATE_DEV_UNCONNECTED;
1680         spin_unlock_irq(&dev->lock);
1681         get_dev (dev);
1682         return 0;
1683
1684 enomem:
1685         gadgetfs_unbind (gadget);
1686         return -ENOMEM;
1687 }
1688
1689 static void
1690 gadgetfs_disconnect (struct usb_gadget *gadget)
1691 {
1692         struct dev_data         *dev = get_gadget_data (gadget);
1693         unsigned long           flags;
1694
1695         spin_lock_irqsave (&dev->lock, flags);
1696         if (dev->state == STATE_DEV_UNCONNECTED)
1697                 goto exit;
1698         dev->state = STATE_DEV_UNCONNECTED;
1699
1700         INFO (dev, "disconnected\n");
1701         next_event (dev, GADGETFS_DISCONNECT);
1702         ep0_readable (dev);
1703 exit:
1704         spin_unlock_irqrestore (&dev->lock, flags);
1705 }
1706
1707 static void
1708 gadgetfs_suspend (struct usb_gadget *gadget)
1709 {
1710         struct dev_data         *dev = get_gadget_data (gadget);
1711         unsigned long           flags;
1712
1713         INFO (dev, "suspended from state %d\n", dev->state);
1714         spin_lock_irqsave(&dev->lock, flags);
1715         switch (dev->state) {
1716         case STATE_DEV_SETUP:           // VERY odd... host died??
1717         case STATE_DEV_CONNECTED:
1718         case STATE_DEV_UNCONNECTED:
1719                 next_event (dev, GADGETFS_SUSPEND);
1720                 ep0_readable (dev);
1721                 fallthrough;
1722         default:
1723                 break;
1724         }
1725         spin_unlock_irqrestore(&dev->lock, flags);
1726 }
1727
1728 static struct usb_gadget_driver gadgetfs_driver = {
1729         .function       = (char *) driver_desc,
1730         .bind           = gadgetfs_bind,
1731         .unbind         = gadgetfs_unbind,
1732         .setup          = gadgetfs_setup,
1733         .reset          = gadgetfs_disconnect,
1734         .disconnect     = gadgetfs_disconnect,
1735         .suspend        = gadgetfs_suspend,
1736
1737         .driver = {
1738                 .name           = shortname,
1739         },
1740 };
1741
1742 /*----------------------------------------------------------------------*/
1743 /* DEVICE INITIALIZATION
1744  *
1745  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1746  *     status = write (fd, descriptors, sizeof descriptors)
1747  *
1748  * That write establishes the device configuration, so the kernel can
1749  * bind to the controller ... guaranteeing it can handle enumeration
1750  * at all necessary speeds.  Descriptor order is:
1751  *
1752  * . message tag (u32, host order) ... for now, must be zero; it
1753  *      would change to support features like multi-config devices
1754  * . full/low speed config ... all wTotalLength bytes (with interface,
1755  *      class, altsetting, endpoint, and other descriptors)
1756  * . high speed config ... all descriptors, for high speed operation;
1757  *      this one's optional except for high-speed hardware
1758  * . device descriptor
1759  *
1760  * Endpoints are not yet enabled. Drivers must wait until device
1761  * configuration and interface altsetting changes create
1762  * the need to configure (or unconfigure) them.
1763  *
1764  * After initialization, the device stays active for as long as that
1765  * $CHIP file is open.  Events must then be read from that descriptor,
1766  * such as configuration notifications.
1767  */
1768
1769 static int is_valid_config(struct usb_config_descriptor *config,
1770                 unsigned int total)
1771 {
1772         return config->bDescriptorType == USB_DT_CONFIG
1773                 && config->bLength == USB_DT_CONFIG_SIZE
1774                 && total >= USB_DT_CONFIG_SIZE
1775                 && config->bConfigurationValue != 0
1776                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1777                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1778         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1779         /* FIXME check lengths: walk to end */
1780 }
1781
1782 static ssize_t
1783 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1784 {
1785         struct dev_data         *dev = fd->private_data;
1786         ssize_t                 value, length = len;
1787         unsigned                total;
1788         u32                     tag;
1789         char                    *kbuf;
1790
1791         spin_lock_irq(&dev->lock);
1792         if (dev->state > STATE_DEV_OPENED) {
1793                 value = ep0_write(fd, buf, len, ptr);
1794                 spin_unlock_irq(&dev->lock);
1795                 return value;
1796         }
1797         spin_unlock_irq(&dev->lock);
1798
1799         if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1800             (len > PAGE_SIZE * 4))
1801                 return -EINVAL;
1802
1803         /* we might need to change message format someday */
1804         if (copy_from_user (&tag, buf, 4))
1805                 return -EFAULT;
1806         if (tag != 0)
1807                 return -EINVAL;
1808         buf += 4;
1809         length -= 4;
1810
1811         kbuf = memdup_user(buf, length);
1812         if (IS_ERR(kbuf))
1813                 return PTR_ERR(kbuf);
1814
1815         spin_lock_irq (&dev->lock);
1816         value = -EINVAL;
1817         if (dev->buf) {
1818                 kfree(kbuf);
1819                 goto fail;
1820         }
1821         dev->buf = kbuf;
1822
1823         /* full or low speed config */
1824         dev->config = (void *) kbuf;
1825         total = le16_to_cpu(dev->config->wTotalLength);
1826         if (!is_valid_config(dev->config, total) ||
1827                         total > length - USB_DT_DEVICE_SIZE)
1828                 goto fail;
1829         kbuf += total;
1830         length -= total;
1831
1832         /* optional high speed config */
1833         if (kbuf [1] == USB_DT_CONFIG) {
1834                 dev->hs_config = (void *) kbuf;
1835                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1836                 if (!is_valid_config(dev->hs_config, total) ||
1837                                 total > length - USB_DT_DEVICE_SIZE)
1838                         goto fail;
1839                 kbuf += total;
1840                 length -= total;
1841         } else {
1842                 dev->hs_config = NULL;
1843         }
1844
1845         /* could support multiple configs, using another encoding! */
1846
1847         /* device descriptor (tweaked for paranoia) */
1848         if (length != USB_DT_DEVICE_SIZE)
1849                 goto fail;
1850         dev->dev = (void *)kbuf;
1851         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1852                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1853                         || dev->dev->bNumConfigurations != 1)
1854                 goto fail;
1855         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1856
1857         /* triggers gadgetfs_bind(); then we can enumerate. */
1858         spin_unlock_irq (&dev->lock);
1859         if (dev->hs_config)
1860                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1861         else
1862                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1863
1864         value = usb_gadget_probe_driver(&gadgetfs_driver);
1865         if (value != 0) {
1866                 kfree (dev->buf);
1867                 dev->buf = NULL;
1868         } else {
1869                 /* at this point "good" hardware has for the first time
1870                  * let the USB the host see us.  alternatively, if users
1871                  * unplug/replug that will clear all the error state.
1872                  *
1873                  * note:  everything running before here was guaranteed
1874                  * to choke driver model style diagnostics.  from here
1875                  * on, they can work ... except in cleanup paths that
1876                  * kick in after the ep0 descriptor is closed.
1877                  */
1878                 value = len;
1879                 dev->gadget_registered = true;
1880         }
1881         return value;
1882
1883 fail:
1884         spin_unlock_irq (&dev->lock);
1885         pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev);
1886         kfree (dev->buf);
1887         dev->buf = NULL;
1888         return value;
1889 }
1890
1891 static int
1892 dev_open (struct inode *inode, struct file *fd)
1893 {
1894         struct dev_data         *dev = inode->i_private;
1895         int                     value = -EBUSY;
1896
1897         spin_lock_irq(&dev->lock);
1898         if (dev->state == STATE_DEV_DISABLED) {
1899                 dev->ev_next = 0;
1900                 dev->state = STATE_DEV_OPENED;
1901                 fd->private_data = dev;
1902                 get_dev (dev);
1903                 value = 0;
1904         }
1905         spin_unlock_irq(&dev->lock);
1906         return value;
1907 }
1908
1909 static const struct file_operations ep0_operations = {
1910         .llseek =       no_llseek,
1911
1912         .open =         dev_open,
1913         .read =         ep0_read,
1914         .write =        dev_config,
1915         .fasync =       ep0_fasync,
1916         .poll =         ep0_poll,
1917         .unlocked_ioctl = dev_ioctl,
1918         .release =      dev_release,
1919 };
1920
1921 /*----------------------------------------------------------------------*/
1922
1923 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1924  *
1925  * Mounting the filesystem creates a controller file, used first for
1926  * device configuration then later for event monitoring.
1927  */
1928
1929
1930 /* FIXME PAM etc could set this security policy without mount options
1931  * if epfiles inherited ownership and permissons from ep0 ...
1932  */
1933
1934 static unsigned default_uid;
1935 static unsigned default_gid;
1936 static unsigned default_perm = S_IRUSR | S_IWUSR;
1937
1938 module_param (default_uid, uint, 0644);
1939 module_param (default_gid, uint, 0644);
1940 module_param (default_perm, uint, 0644);
1941
1942
1943 static struct inode *
1944 gadgetfs_make_inode (struct super_block *sb,
1945                 void *data, const struct file_operations *fops,
1946                 int mode)
1947 {
1948         struct inode *inode = new_inode (sb);
1949
1950         if (inode) {
1951                 inode->i_ino = get_next_ino();
1952                 inode->i_mode = mode;
1953                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
1954                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
1955                 inode->i_atime = inode->i_mtime = inode->i_ctime
1956                                 = current_time(inode);
1957                 inode->i_private = data;
1958                 inode->i_fop = fops;
1959         }
1960         return inode;
1961 }
1962
1963 /* creates in fs root directory, so non-renamable and non-linkable.
1964  * so inode and dentry are paired, until device reconfig.
1965  */
1966 static struct dentry *
1967 gadgetfs_create_file (struct super_block *sb, char const *name,
1968                 void *data, const struct file_operations *fops)
1969 {
1970         struct dentry   *dentry;
1971         struct inode    *inode;
1972
1973         dentry = d_alloc_name(sb->s_root, name);
1974         if (!dentry)
1975                 return NULL;
1976
1977         inode = gadgetfs_make_inode (sb, data, fops,
1978                         S_IFREG | (default_perm & S_IRWXUGO));
1979         if (!inode) {
1980                 dput(dentry);
1981                 return NULL;
1982         }
1983         d_add (dentry, inode);
1984         return dentry;
1985 }
1986
1987 static const struct super_operations gadget_fs_operations = {
1988         .statfs =       simple_statfs,
1989         .drop_inode =   generic_delete_inode,
1990 };
1991
1992 static int
1993 gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc)
1994 {
1995         struct inode    *inode;
1996         struct dev_data *dev;
1997
1998         if (the_device)
1999                 return -ESRCH;
2000
2001         CHIP = usb_get_gadget_udc_name();
2002         if (!CHIP)
2003                 return -ENODEV;
2004
2005         /* superblock */
2006         sb->s_blocksize = PAGE_SIZE;
2007         sb->s_blocksize_bits = PAGE_SHIFT;
2008         sb->s_magic = GADGETFS_MAGIC;
2009         sb->s_op = &gadget_fs_operations;
2010         sb->s_time_gran = 1;
2011
2012         /* root inode */
2013         inode = gadgetfs_make_inode (sb,
2014                         NULL, &simple_dir_operations,
2015                         S_IFDIR | S_IRUGO | S_IXUGO);
2016         if (!inode)
2017                 goto Enomem;
2018         inode->i_op = &simple_dir_inode_operations;
2019         if (!(sb->s_root = d_make_root (inode)))
2020                 goto Enomem;
2021
2022         /* the ep0 file is named after the controller we expect;
2023          * user mode code can use it for sanity checks, like we do.
2024          */
2025         dev = dev_new ();
2026         if (!dev)
2027                 goto Enomem;
2028
2029         dev->sb = sb;
2030         dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2031         if (!dev->dentry) {
2032                 put_dev(dev);
2033                 goto Enomem;
2034         }
2035
2036         /* other endpoint files are available after hardware setup,
2037          * from binding to a controller.
2038          */
2039         the_device = dev;
2040         return 0;
2041
2042 Enomem:
2043         kfree(CHIP);
2044         CHIP = NULL;
2045
2046         return -ENOMEM;
2047 }
2048
2049 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2050 static int gadgetfs_get_tree(struct fs_context *fc)
2051 {
2052         return get_tree_single(fc, gadgetfs_fill_super);
2053 }
2054
2055 static const struct fs_context_operations gadgetfs_context_ops = {
2056         .get_tree       = gadgetfs_get_tree,
2057 };
2058
2059 static int gadgetfs_init_fs_context(struct fs_context *fc)
2060 {
2061         fc->ops = &gadgetfs_context_ops;
2062         return 0;
2063 }
2064
2065 static void
2066 gadgetfs_kill_sb (struct super_block *sb)
2067 {
2068         kill_litter_super (sb);
2069         if (the_device) {
2070                 put_dev (the_device);
2071                 the_device = NULL;
2072         }
2073         kfree(CHIP);
2074         CHIP = NULL;
2075 }
2076
2077 /*----------------------------------------------------------------------*/
2078
2079 static struct file_system_type gadgetfs_type = {
2080         .owner          = THIS_MODULE,
2081         .name           = shortname,
2082         .init_fs_context = gadgetfs_init_fs_context,
2083         .kill_sb        = gadgetfs_kill_sb,
2084 };
2085 MODULE_ALIAS_FS("gadgetfs");
2086
2087 /*----------------------------------------------------------------------*/
2088
2089 static int __init init (void)
2090 {
2091         int status;
2092
2093         status = register_filesystem (&gadgetfs_type);
2094         if (status == 0)
2095                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2096                         shortname, driver_desc);
2097         return status;
2098 }
2099 module_init (init);
2100
2101 static void __exit cleanup (void)
2102 {
2103         pr_debug ("unregister %s\n", shortname);
2104         unregister_filesystem (&gadgetfs_type);
2105 }
2106 module_exit (cleanup);
2107