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