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Linux/drivers/usb/gadget/inode.c

  1 /*
  2  * inode.c -- user mode filesystem api for usb gadget controllers
  3  *
  4  * Copyright (C) 2003-2004 David Brownell
  5  * Copyright (C) 2003 Agilent Technologies
  6  *
  7  * This program is free software; you can redistribute it and/or modify
  8  * it under the terms of the GNU General Public License as published by
  9  * the Free Software Foundation; either version 2 of the License, or
 10  * (at your option) any later version.
 11  */
 12 
 13 
 14 /* #define VERBOSE_DEBUG */
 15 
 16 #include <linux/init.h>
 17 #include <linux/module.h>
 18 #include <linux/fs.h>
 19 #include <linux/pagemap.h>
 20 #include <linux/uts.h>
 21 #include <linux/wait.h>
 22 #include <linux/compiler.h>
 23 #include <asm/uaccess.h>
 24 #include <linux/sched.h>
 25 #include <linux/slab.h>
 26 #include <linux/poll.h>
 27 #include <linux/mmu_context.h>
 28 #include <linux/aio.h>
 29 
 30 #include <linux/device.h>
 31 #include <linux/moduleparam.h>
 32 
 33 #include <linux/usb/gadgetfs.h>
 34 #include <linux/usb/gadget.h>
 35 
 36 
 37 /*
 38  * The gadgetfs API maps each endpoint to a file descriptor so that you
 39  * can use standard synchronous read/write calls for I/O.  There's some
 40  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
 41  * drivers show how this works in practice.  You can also use AIO to
 42  * eliminate I/O gaps between requests, to help when streaming data.
 43  *
 44  * Key parts that must be USB-specific are protocols defining how the
 45  * read/write operations relate to the hardware state machines.  There
 46  * are two types of files.  One type is for the device, implementing ep0.
 47  * The other type is for each IN or OUT endpoint.  In both cases, the
 48  * user mode driver must configure the hardware before using it.
 49  *
 50  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
 51  *   (by writing configuration and device descriptors).  Afterwards it
 52  *   may serve as a source of device events, used to handle all control
 53  *   requests other than basic enumeration.
 54  *
 55  * - Then, after a SET_CONFIGURATION control request, ep_config() is
 56  *   called when each /dev/gadget/ep* file is configured (by writing
 57  *   endpoint descriptors).  Afterwards these files are used to write()
 58  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
 59  *   direction" request is issued (like reading an IN endpoint).
 60  *
 61  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
 62  * not possible on all hardware.  For example, precise fault handling with
 63  * respect to data left in endpoint fifos after aborted operations; or
 64  * selective clearing of endpoint halts, to implement SET_INTERFACE.
 65  */
 66 
 67 #define DRIVER_DESC     "USB Gadget filesystem"
 68 #define DRIVER_VERSION  "24 Aug 2004"
 69 
 70 static const char driver_desc [] = DRIVER_DESC;
 71 static const char shortname [] = "gadgetfs";
 72 
 73 MODULE_DESCRIPTION (DRIVER_DESC);
 74 MODULE_AUTHOR ("David Brownell");
 75 MODULE_LICENSE ("GPL");
 76 
 77 
 78 /*----------------------------------------------------------------------*/
 79 
 80 #define GADGETFS_MAGIC          0xaee71ee7
 81 
 82 /* /dev/gadget/$CHIP represents ep0 and the whole device */
 83 enum ep0_state {
 84         /* DISBLED is the initial state.
 85          */
 86         STATE_DEV_DISABLED = 0,
 87 
 88         /* Only one open() of /dev/gadget/$CHIP; only one file tracks
 89          * ep0/device i/o modes and binding to the controller.  Driver
 90          * must always write descriptors to initialize the device, then
 91          * the device becomes UNCONNECTED until enumeration.
 92          */
 93         STATE_DEV_OPENED,
 94 
 95         /* From then on, ep0 fd is in either of two basic modes:
 96          * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
 97          * - SETUP: read/write will transfer control data and succeed;
 98          *   or if "wrong direction", performs protocol stall
 99          */
100         STATE_DEV_UNCONNECTED,
101         STATE_DEV_CONNECTED,
102         STATE_DEV_SETUP,
103 
104         /* UNBOUND means the driver closed ep0, so the device won't be
105          * accessible again (DEV_DISABLED) until all fds are closed.
106          */
107         STATE_DEV_UNBOUND,
108 };
109 
110 /* enough for the whole queue: most events invalidate others */
111 #define N_EVENT                 5
112 
113 struct dev_data {
114         spinlock_t                      lock;
115         atomic_t                        count;
116         enum ep0_state                  state;          /* P: lock */
117         struct usb_gadgetfs_event       event [N_EVENT];
118         unsigned                        ev_next;
119         struct fasync_struct            *fasync;
120         u8                              current_config;
121 
122         /* drivers reading ep0 MUST handle control requests (SETUP)
123          * reported that way; else the host will time out.
124          */
125         unsigned                        usermode_setup : 1,
126                                         setup_in : 1,
127                                         setup_can_stall : 1,
128                                         setup_out_ready : 1,
129                                         setup_out_error : 1,
130                                         setup_abort : 1;
131         unsigned                        setup_wLength;
132 
133         /* the rest is basically write-once */
134         struct usb_config_descriptor    *config, *hs_config;
135         struct usb_device_descriptor    *dev;
136         struct usb_request              *req;
137         struct usb_gadget               *gadget;
138         struct list_head                epfiles;
139         void                            *buf;
140         wait_queue_head_t               wait;
141         struct super_block              *sb;
142         struct dentry                   *dentry;
143 
144         /* except this scratch i/o buffer for ep0 */
145         u8                              rbuf [256];
146 };
147 
148 static inline void get_dev (struct dev_data *data)
149 {
150         atomic_inc (&data->count);
151 }
152 
153 static void put_dev (struct dev_data *data)
154 {
155         if (likely (!atomic_dec_and_test (&data->count)))
156                 return;
157         /* needs no more cleanup */
158         BUG_ON (waitqueue_active (&data->wait));
159         kfree (data);
160 }
161 
162 static struct dev_data *dev_new (void)
163 {
164         struct dev_data         *dev;
165 
166         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
167         if (!dev)
168                 return NULL;
169         dev->state = STATE_DEV_DISABLED;
170         atomic_set (&dev->count, 1);
171         spin_lock_init (&dev->lock);
172         INIT_LIST_HEAD (&dev->epfiles);
173         init_waitqueue_head (&dev->wait);
174         return dev;
175 }
176 
177 /*----------------------------------------------------------------------*/
178 
179 /* other /dev/gadget/$ENDPOINT files represent endpoints */
180 enum ep_state {
181         STATE_EP_DISABLED = 0,
182         STATE_EP_READY,
183         STATE_EP_ENABLED,
184         STATE_EP_UNBOUND,
185 };
186 
187 struct ep_data {
188         struct mutex                    lock;
189         enum ep_state                   state;
190         atomic_t                        count;
191         struct dev_data                 *dev;
192         /* must hold dev->lock before accessing ep or req */
193         struct usb_ep                   *ep;
194         struct usb_request              *req;
195         ssize_t                         status;
196         char                            name [16];
197         struct usb_endpoint_descriptor  desc, hs_desc;
198         struct list_head                epfiles;
199         wait_queue_head_t               wait;
200         struct dentry                   *dentry;
201         struct inode                    *inode;
202 };
203 
204 static inline void get_ep (struct ep_data *data)
205 {
206         atomic_inc (&data->count);
207 }
208 
209 static void put_ep (struct ep_data *data)
210 {
211         if (likely (!atomic_dec_and_test (&data->count)))
212                 return;
213         put_dev (data->dev);
214         /* needs no more cleanup */
215         BUG_ON (!list_empty (&data->epfiles));
216         BUG_ON (waitqueue_active (&data->wait));
217         kfree (data);
218 }
219 
220 /*----------------------------------------------------------------------*/
221 
222 /* most "how to use the hardware" policy choices are in userspace:
223  * mapping endpoint roles (which the driver needs) to the capabilities
224  * which the usb controller has.  most of those capabilities are exposed
225  * implicitly, starting with the driver name and then endpoint names.
226  */
227 
228 static const char *CHIP;
229 
230 /*----------------------------------------------------------------------*/
231 
232 /* NOTE:  don't use dev_printk calls before binding to the gadget
233  * at the end of ep0 configuration, or after unbind.
234  */
235 
236 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
237 #define xprintk(d,level,fmt,args...) \
238         printk(level "%s: " fmt , shortname , ## args)
239 
240 #ifdef DEBUG
241 #define DBG(dev,fmt,args...) \
242         xprintk(dev , KERN_DEBUG , fmt , ## args)
243 #else
244 #define DBG(dev,fmt,args...) \
245         do { } while (0)
246 #endif /* DEBUG */
247 
248 #ifdef VERBOSE_DEBUG
249 #define VDEBUG  DBG
250 #else
251 #define VDEBUG(dev,fmt,args...) \
252         do { } while (0)
253 #endif /* DEBUG */
254 
255 #define ERROR(dev,fmt,args...) \
256         xprintk(dev , KERN_ERR , fmt , ## args)
257 #define INFO(dev,fmt,args...) \
258         xprintk(dev , KERN_INFO , fmt , ## args)
259 
260 
261 /*----------------------------------------------------------------------*/
262 
263 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
264  *
265  * After opening, configure non-control endpoints.  Then use normal
266  * stream read() and write() requests; and maybe ioctl() to get more
267  * precise FIFO status when recovering from cancellation.
268  */
269 
270 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
271 {
272         struct ep_data  *epdata = ep->driver_data;
273 
274         if (!req->context)
275                 return;
276         if (req->status)
277                 epdata->status = req->status;
278         else
279                 epdata->status = req->actual;
280         complete ((struct completion *)req->context);
281 }
282 
283 /* tasklock endpoint, returning when it's connected.
284  * still need dev->lock to use epdata->ep.
285  */
286 static int
287 get_ready_ep (unsigned f_flags, struct ep_data *epdata)
288 {
289         int     val;
290 
291         if (f_flags & O_NONBLOCK) {
292                 if (!mutex_trylock(&epdata->lock))
293                         goto nonblock;
294                 if (epdata->state != STATE_EP_ENABLED) {
295                         mutex_unlock(&epdata->lock);
296 nonblock:
297                         val = -EAGAIN;
298                 } else
299                         val = 0;
300                 return val;
301         }
302 
303         val = mutex_lock_interruptible(&epdata->lock);
304         if (val < 0)
305                 return val;
306 
307         switch (epdata->state) {
308         case STATE_EP_ENABLED:
309                 break;
310         // case STATE_EP_DISABLED:              /* "can't happen" */
311         // case STATE_EP_READY:                 /* "can't happen" */
312         default:                                /* error! */
313                 pr_debug ("%s: ep %p not available, state %d\n",
314                                 shortname, epdata, epdata->state);
315                 // FALLTHROUGH
316         case STATE_EP_UNBOUND:                  /* clean disconnect */
317                 val = -ENODEV;
318                 mutex_unlock(&epdata->lock);
319         }
320         return val;
321 }
322 
323 static ssize_t
324 ep_io (struct ep_data *epdata, void *buf, unsigned len)
325 {
326         DECLARE_COMPLETION_ONSTACK (done);
327         int value;
328 
329         spin_lock_irq (&epdata->dev->lock);
330         if (likely (epdata->ep != NULL)) {
331                 struct usb_request      *req = epdata->req;
332 
333                 req->context = &done;
334                 req->complete = epio_complete;
335                 req->buf = buf;
336                 req->length = len;
337                 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
338         } else
339                 value = -ENODEV;
340         spin_unlock_irq (&epdata->dev->lock);
341 
342         if (likely (value == 0)) {
343                 value = wait_event_interruptible (done.wait, done.done);
344                 if (value != 0) {
345                         spin_lock_irq (&epdata->dev->lock);
346                         if (likely (epdata->ep != NULL)) {
347                                 DBG (epdata->dev, "%s i/o interrupted\n",
348                                                 epdata->name);
349                                 usb_ep_dequeue (epdata->ep, epdata->req);
350                                 spin_unlock_irq (&epdata->dev->lock);
351 
352                                 wait_event (done.wait, done.done);
353                                 if (epdata->status == -ECONNRESET)
354                                         epdata->status = -EINTR;
355                         } else {
356                                 spin_unlock_irq (&epdata->dev->lock);
357 
358                                 DBG (epdata->dev, "endpoint gone\n");
359                                 epdata->status = -ENODEV;
360                         }
361                 }
362                 return epdata->status;
363         }
364         return value;
365 }
366 
367 
368 /* handle a synchronous OUT bulk/intr/iso transfer */
369 static ssize_t
370 ep_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
371 {
372         struct ep_data          *data = fd->private_data;
373         void                    *kbuf;
374         ssize_t                 value;
375 
376         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
377                 return value;
378 
379         /* halt any endpoint by doing a "wrong direction" i/o call */
380         if (usb_endpoint_dir_in(&data->desc)) {
381                 if (usb_endpoint_xfer_isoc(&data->desc)) {
382                         mutex_unlock(&data->lock);
383                         return -EINVAL;
384                 }
385                 DBG (data->dev, "%s halt\n", data->name);
386                 spin_lock_irq (&data->dev->lock);
387                 if (likely (data->ep != NULL))
388                         usb_ep_set_halt (data->ep);
389                 spin_unlock_irq (&data->dev->lock);
390                 mutex_unlock(&data->lock);
391                 return -EBADMSG;
392         }
393 
394         /* FIXME readahead for O_NONBLOCK and poll(); careful with ZLPs */
395 
396         value = -ENOMEM;
397         kbuf = kmalloc (len, GFP_KERNEL);
398         if (unlikely (!kbuf))
399                 goto free1;
400 
401         value = ep_io (data, kbuf, len);
402         VDEBUG (data->dev, "%s read %zu OUT, status %d\n",
403                 data->name, len, (int) value);
404         if (value >= 0 && copy_to_user (buf, kbuf, value))
405                 value = -EFAULT;
406 
407 free1:
408         mutex_unlock(&data->lock);
409         kfree (kbuf);
410         return value;
411 }
412 
413 /* handle a synchronous IN bulk/intr/iso transfer */
414 static ssize_t
415 ep_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
416 {
417         struct ep_data          *data = fd->private_data;
418         void                    *kbuf;
419         ssize_t                 value;
420 
421         if ((value = get_ready_ep (fd->f_flags, data)) < 0)
422                 return value;
423 
424         /* halt any endpoint by doing a "wrong direction" i/o call */
425         if (!usb_endpoint_dir_in(&data->desc)) {
426                 if (usb_endpoint_xfer_isoc(&data->desc)) {
427                         mutex_unlock(&data->lock);
428                         return -EINVAL;
429                 }
430                 DBG (data->dev, "%s halt\n", data->name);
431                 spin_lock_irq (&data->dev->lock);
432                 if (likely (data->ep != NULL))
433                         usb_ep_set_halt (data->ep);
434                 spin_unlock_irq (&data->dev->lock);
435                 mutex_unlock(&data->lock);
436                 return -EBADMSG;
437         }
438 
439         /* FIXME writebehind for O_NONBLOCK and poll(), qlen = 1 */
440 
441         value = -ENOMEM;
442         kbuf = memdup_user(buf, len);
443         if (!kbuf) {
444                 value = PTR_ERR(kbuf);
445                 goto free1;
446         }
447 
448         value = ep_io (data, kbuf, len);
449         VDEBUG (data->dev, "%s write %zu IN, status %d\n",
450                 data->name, len, (int) value);
451 free1:
452         mutex_unlock(&data->lock);
453         return value;
454 }
455 
456 static int
457 ep_release (struct inode *inode, struct file *fd)
458 {
459         struct ep_data          *data = fd->private_data;
460         int value;
461 
462         value = mutex_lock_interruptible(&data->lock);
463         if (value < 0)
464                 return value;
465 
466         /* clean up if this can be reopened */
467         if (data->state != STATE_EP_UNBOUND) {
468                 data->state = STATE_EP_DISABLED;
469                 data->desc.bDescriptorType = 0;
470                 data->hs_desc.bDescriptorType = 0;
471                 usb_ep_disable(data->ep);
472         }
473         mutex_unlock(&data->lock);
474         put_ep (data);
475         return 0;
476 }
477 
478 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
479 {
480         struct ep_data          *data = fd->private_data;
481         int                     status;
482 
483         if ((status = get_ready_ep (fd->f_flags, data)) < 0)
484                 return status;
485 
486         spin_lock_irq (&data->dev->lock);
487         if (likely (data->ep != NULL)) {
488                 switch (code) {
489                 case GADGETFS_FIFO_STATUS:
490                         status = usb_ep_fifo_status (data->ep);
491                         break;
492                 case GADGETFS_FIFO_FLUSH:
493                         usb_ep_fifo_flush (data->ep);
494                         break;
495                 case GADGETFS_CLEAR_HALT:
496                         status = usb_ep_clear_halt (data->ep);
497                         break;
498                 default:
499                         status = -ENOTTY;
500                 }
501         } else
502                 status = -ENODEV;
503         spin_unlock_irq (&data->dev->lock);
504         mutex_unlock(&data->lock);
505         return status;
506 }
507 
508 /*----------------------------------------------------------------------*/
509 
510 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
511 
512 struct kiocb_priv {
513         struct usb_request      *req;
514         struct ep_data          *epdata;
515         struct kiocb            *iocb;
516         struct mm_struct        *mm;
517         struct work_struct      work;
518         void                    *buf;
519         const struct iovec      *iv;
520         unsigned long           nr_segs;
521         unsigned                actual;
522 };
523 
524 static int ep_aio_cancel(struct kiocb *iocb)
525 {
526         struct kiocb_priv       *priv = iocb->private;
527         struct ep_data          *epdata;
528         int                     value;
529 
530         local_irq_disable();
531         epdata = priv->epdata;
532         // spin_lock(&epdata->dev->lock);
533         if (likely(epdata && epdata->ep && priv->req))
534                 value = usb_ep_dequeue (epdata->ep, priv->req);
535         else
536                 value = -EINVAL;
537         // spin_unlock(&epdata->dev->lock);
538         local_irq_enable();
539 
540         return value;
541 }
542 
543 static ssize_t ep_copy_to_user(struct kiocb_priv *priv)
544 {
545         ssize_t                 len, total;
546         void                    *to_copy;
547         int                     i;
548 
549         /* copy stuff into user buffers */
550         total = priv->actual;
551         len = 0;
552         to_copy = priv->buf;
553         for (i=0; i < priv->nr_segs; i++) {
554                 ssize_t this = min((ssize_t)(priv->iv[i].iov_len), total);
555 
556                 if (copy_to_user(priv->iv[i].iov_base, to_copy, this)) {
557                         if (len == 0)
558                                 len = -EFAULT;
559                         break;
560                 }
561 
562                 total -= this;
563                 len += this;
564                 to_copy += this;
565                 if (total == 0)
566                         break;
567         }
568 
569         return len;
570 }
571 
572 static void ep_user_copy_worker(struct work_struct *work)
573 {
574         struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
575         struct mm_struct *mm = priv->mm;
576         struct kiocb *iocb = priv->iocb;
577         size_t ret;
578 
579         use_mm(mm);
580         ret = ep_copy_to_user(priv);
581         unuse_mm(mm);
582 
583         /* completing the iocb can drop the ctx and mm, don't touch mm after */
584         aio_complete(iocb, ret, ret);
585 
586         kfree(priv->buf);
587         kfree(priv);
588 }
589 
590 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
591 {
592         struct kiocb            *iocb = req->context;
593         struct kiocb_priv       *priv = iocb->private;
594         struct ep_data          *epdata = priv->epdata;
595 
596         /* lock against disconnect (and ideally, cancel) */
597         spin_lock(&epdata->dev->lock);
598         priv->req = NULL;
599         priv->epdata = NULL;
600 
601         /* if this was a write or a read returning no data then we
602          * don't need to copy anything to userspace, so we can
603          * complete the aio request immediately.
604          */
605         if (priv->iv == NULL || unlikely(req->actual == 0)) {
606                 kfree(req->buf);
607                 kfree(priv);
608                 iocb->private = NULL;
609                 /* aio_complete() reports bytes-transferred _and_ faults */
610                 aio_complete(iocb, req->actual ? req->actual : req->status,
611                                 req->status);
612         } else {
613                 /* ep_copy_to_user() won't report both; we hide some faults */
614                 if (unlikely(0 != req->status))
615                         DBG(epdata->dev, "%s fault %d len %d\n",
616                                 ep->name, req->status, req->actual);
617 
618                 priv->buf = req->buf;
619                 priv->actual = req->actual;
620                 schedule_work(&priv->work);
621         }
622         spin_unlock(&epdata->dev->lock);
623 
624         usb_ep_free_request(ep, req);
625         put_ep(epdata);
626 }
627 
628 static ssize_t
629 ep_aio_rwtail(
630         struct kiocb    *iocb,
631         char            *buf,
632         size_t          len,
633         struct ep_data  *epdata,
634         const struct iovec *iv,
635         unsigned long   nr_segs
636 )
637 {
638         struct kiocb_priv       *priv;
639         struct usb_request      *req;
640         ssize_t                 value;
641 
642         priv = kmalloc(sizeof *priv, GFP_KERNEL);
643         if (!priv) {
644                 value = -ENOMEM;
645 fail:
646                 kfree(buf);
647                 return value;
648         }
649         iocb->private = priv;
650         priv->iocb = iocb;
651         priv->iv = iv;
652         priv->nr_segs = nr_segs;
653         INIT_WORK(&priv->work, ep_user_copy_worker);
654 
655         value = get_ready_ep(iocb->ki_filp->f_flags, epdata);
656         if (unlikely(value < 0)) {
657                 kfree(priv);
658                 goto fail;
659         }
660 
661         kiocb_set_cancel_fn(iocb, ep_aio_cancel);
662         get_ep(epdata);
663         priv->epdata = epdata;
664         priv->actual = 0;
665         priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
666 
667         /* each kiocb is coupled to one usb_request, but we can't
668          * allocate or submit those if the host disconnected.
669          */
670         spin_lock_irq(&epdata->dev->lock);
671         if (likely(epdata->ep)) {
672                 req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
673                 if (likely(req)) {
674                         priv->req = req;
675                         req->buf = buf;
676                         req->length = len;
677                         req->complete = ep_aio_complete;
678                         req->context = iocb;
679                         value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
680                         if (unlikely(0 != value))
681                                 usb_ep_free_request(epdata->ep, req);
682                 } else
683                         value = -EAGAIN;
684         } else
685                 value = -ENODEV;
686         spin_unlock_irq(&epdata->dev->lock);
687 
688         mutex_unlock(&epdata->lock);
689 
690         if (unlikely(value)) {
691                 kfree(priv);
692                 put_ep(epdata);
693         } else
694                 value = -EIOCBQUEUED;
695         return value;
696 }
697 
698 static ssize_t
699 ep_aio_read(struct kiocb *iocb, const struct iovec *iov,
700                 unsigned long nr_segs, loff_t o)
701 {
702         struct ep_data          *epdata = iocb->ki_filp->private_data;
703         char                    *buf;
704 
705         if (unlikely(usb_endpoint_dir_in(&epdata->desc)))
706                 return -EINVAL;
707 
708         buf = kmalloc(iocb->ki_nbytes, GFP_KERNEL);
709         if (unlikely(!buf))
710                 return -ENOMEM;
711 
712         return ep_aio_rwtail(iocb, buf, iocb->ki_nbytes, epdata, iov, nr_segs);
713 }
714 
715 static ssize_t
716 ep_aio_write(struct kiocb *iocb, const struct iovec *iov,
717                 unsigned long nr_segs, loff_t o)
718 {
719         struct ep_data          *epdata = iocb->ki_filp->private_data;
720         char                    *buf;
721         size_t                  len = 0;
722         int                     i = 0;
723 
724         if (unlikely(!usb_endpoint_dir_in(&epdata->desc)))
725                 return -EINVAL;
726 
727         buf = kmalloc(iocb->ki_nbytes, GFP_KERNEL);
728         if (unlikely(!buf))
729                 return -ENOMEM;
730 
731         for (i=0; i < nr_segs; i++) {
732                 if (unlikely(copy_from_user(&buf[len], iov[i].iov_base,
733                                 iov[i].iov_len) != 0)) {
734                         kfree(buf);
735                         return -EFAULT;
736                 }
737                 len += iov[i].iov_len;
738         }
739         return ep_aio_rwtail(iocb, buf, len, epdata, NULL, 0);
740 }
741 
742 /*----------------------------------------------------------------------*/
743 
744 /* used after endpoint configuration */
745 static const struct file_operations ep_io_operations = {
746         .owner =        THIS_MODULE,
747         .llseek =       no_llseek,
748 
749         .read =         ep_read,
750         .write =        ep_write,
751         .unlocked_ioctl = ep_ioctl,
752         .release =      ep_release,
753 
754         .aio_read =     ep_aio_read,
755         .aio_write =    ep_aio_write,
756 };
757 
758 /* ENDPOINT INITIALIZATION
759  *
760  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
761  *     status = write (fd, descriptors, sizeof descriptors)
762  *
763  * That write establishes the endpoint configuration, configuring
764  * the controller to process bulk, interrupt, or isochronous transfers
765  * at the right maxpacket size, and so on.
766  *
767  * The descriptors are message type 1, identified by a host order u32
768  * at the beginning of what's written.  Descriptor order is: full/low
769  * speed descriptor, then optional high speed descriptor.
770  */
771 static ssize_t
772 ep_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
773 {
774         struct ep_data          *data = fd->private_data;
775         struct usb_ep           *ep;
776         u32                     tag;
777         int                     value, length = len;
778 
779         value = mutex_lock_interruptible(&data->lock);
780         if (value < 0)
781                 return value;
782 
783         if (data->state != STATE_EP_READY) {
784                 value = -EL2HLT;
785                 goto fail;
786         }
787 
788         value = len;
789         if (len < USB_DT_ENDPOINT_SIZE + 4)
790                 goto fail0;
791 
792         /* we might need to change message format someday */
793         if (copy_from_user (&tag, buf, 4)) {
794                 goto fail1;
795         }
796         if (tag != 1) {
797                 DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
798                 goto fail0;
799         }
800         buf += 4;
801         len -= 4;
802 
803         /* NOTE:  audio endpoint extensions not accepted here;
804          * just don't include the extra bytes.
805          */
806 
807         /* full/low speed descriptor, then high speed */
808         if (copy_from_user (&data->desc, buf, USB_DT_ENDPOINT_SIZE)) {
809                 goto fail1;
810         }
811         if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
812                         || data->desc.bDescriptorType != USB_DT_ENDPOINT)
813                 goto fail0;
814         if (len != USB_DT_ENDPOINT_SIZE) {
815                 if (len != 2 * USB_DT_ENDPOINT_SIZE)
816                         goto fail0;
817                 if (copy_from_user (&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
818                                         USB_DT_ENDPOINT_SIZE)) {
819                         goto fail1;
820                 }
821                 if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
822                                 || data->hs_desc.bDescriptorType
823                                         != USB_DT_ENDPOINT) {
824                         DBG(data->dev, "config %s, bad hs length or type\n",
825                                         data->name);
826                         goto fail0;
827                 }
828         }
829 
830         spin_lock_irq (&data->dev->lock);
831         if (data->dev->state == STATE_DEV_UNBOUND) {
832                 value = -ENOENT;
833                 goto gone;
834         } else if ((ep = data->ep) == NULL) {
835                 value = -ENODEV;
836                 goto gone;
837         }
838         switch (data->dev->gadget->speed) {
839         case USB_SPEED_LOW:
840         case USB_SPEED_FULL:
841                 ep->desc = &data->desc;
842                 value = usb_ep_enable(ep);
843                 if (value == 0)
844                         data->state = STATE_EP_ENABLED;
845                 break;
846         case USB_SPEED_HIGH:
847                 /* fails if caller didn't provide that descriptor... */
848                 ep->desc = &data->hs_desc;
849                 value = usb_ep_enable(ep);
850                 if (value == 0)
851                         data->state = STATE_EP_ENABLED;
852                 break;
853         default:
854                 DBG(data->dev, "unconnected, %s init abandoned\n",
855                                 data->name);
856                 value = -EINVAL;
857         }
858         if (value == 0) {
859                 fd->f_op = &ep_io_operations;
860                 value = length;
861         }
862 gone:
863         spin_unlock_irq (&data->dev->lock);
864         if (value < 0) {
865 fail:
866                 data->desc.bDescriptorType = 0;
867                 data->hs_desc.bDescriptorType = 0;
868         }
869         mutex_unlock(&data->lock);
870         return value;
871 fail0:
872         value = -EINVAL;
873         goto fail;
874 fail1:
875         value = -EFAULT;
876         goto fail;
877 }
878 
879 static int
880 ep_open (struct inode *inode, struct file *fd)
881 {
882         struct ep_data          *data = inode->i_private;
883         int                     value = -EBUSY;
884 
885         if (mutex_lock_interruptible(&data->lock) != 0)
886                 return -EINTR;
887         spin_lock_irq (&data->dev->lock);
888         if (data->dev->state == STATE_DEV_UNBOUND)
889                 value = -ENOENT;
890         else if (data->state == STATE_EP_DISABLED) {
891                 value = 0;
892                 data->state = STATE_EP_READY;
893                 get_ep (data);
894                 fd->private_data = data;
895                 VDEBUG (data->dev, "%s ready\n", data->name);
896         } else
897                 DBG (data->dev, "%s state %d\n",
898                         data->name, data->state);
899         spin_unlock_irq (&data->dev->lock);
900         mutex_unlock(&data->lock);
901         return value;
902 }
903 
904 /* used before endpoint configuration */
905 static const struct file_operations ep_config_operations = {
906         .llseek =       no_llseek,
907 
908         .open =         ep_open,
909         .write =        ep_config,
910         .release =      ep_release,
911 };
912 
913 /*----------------------------------------------------------------------*/
914 
915 /* EP0 IMPLEMENTATION can be partly in userspace.
916  *
917  * Drivers that use this facility receive various events, including
918  * control requests the kernel doesn't handle.  Drivers that don't
919  * use this facility may be too simple-minded for real applications.
920  */
921 
922 static inline void ep0_readable (struct dev_data *dev)
923 {
924         wake_up (&dev->wait);
925         kill_fasync (&dev->fasync, SIGIO, POLL_IN);
926 }
927 
928 static void clean_req (struct usb_ep *ep, struct usb_request *req)
929 {
930         struct dev_data         *dev = ep->driver_data;
931 
932         if (req->buf != dev->rbuf) {
933                 kfree(req->buf);
934                 req->buf = dev->rbuf;
935         }
936         req->complete = epio_complete;
937         dev->setup_out_ready = 0;
938 }
939 
940 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
941 {
942         struct dev_data         *dev = ep->driver_data;
943         unsigned long           flags;
944         int                     free = 1;
945 
946         /* for control OUT, data must still get to userspace */
947         spin_lock_irqsave(&dev->lock, flags);
948         if (!dev->setup_in) {
949                 dev->setup_out_error = (req->status != 0);
950                 if (!dev->setup_out_error)
951                         free = 0;
952                 dev->setup_out_ready = 1;
953                 ep0_readable (dev);
954         }
955 
956         /* clean up as appropriate */
957         if (free && req->buf != &dev->rbuf)
958                 clean_req (ep, req);
959         req->complete = epio_complete;
960         spin_unlock_irqrestore(&dev->lock, flags);
961 }
962 
963 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
964 {
965         struct dev_data *dev = ep->driver_data;
966 
967         if (dev->setup_out_ready) {
968                 DBG (dev, "ep0 request busy!\n");
969                 return -EBUSY;
970         }
971         if (len > sizeof (dev->rbuf))
972                 req->buf = kmalloc(len, GFP_ATOMIC);
973         if (req->buf == NULL) {
974                 req->buf = dev->rbuf;
975                 return -ENOMEM;
976         }
977         req->complete = ep0_complete;
978         req->length = len;
979         req->zero = 0;
980         return 0;
981 }
982 
983 static ssize_t
984 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
985 {
986         struct dev_data                 *dev = fd->private_data;
987         ssize_t                         retval;
988         enum ep0_state                  state;
989 
990         spin_lock_irq (&dev->lock);
991 
992         /* report fd mode change before acting on it */
993         if (dev->setup_abort) {
994                 dev->setup_abort = 0;
995                 retval = -EIDRM;
996                 goto done;
997         }
998 
999         /* control DATA stage */
1000         if ((state = dev->state) == STATE_DEV_SETUP) {
1001 
1002                 if (dev->setup_in) {            /* stall IN */
1003                         VDEBUG(dev, "ep0in stall\n");
1004                         (void) usb_ep_set_halt (dev->gadget->ep0);
1005                         retval = -EL2HLT;
1006                         dev->state = STATE_DEV_CONNECTED;
1007 
1008                 } else if (len == 0) {          /* ack SET_CONFIGURATION etc */
1009                         struct usb_ep           *ep = dev->gadget->ep0;
1010                         struct usb_request      *req = dev->req;
1011 
1012                         if ((retval = setup_req (ep, req, 0)) == 0)
1013                                 retval = usb_ep_queue (ep, req, GFP_ATOMIC);
1014                         dev->state = STATE_DEV_CONNECTED;
1015 
1016                         /* assume that was SET_CONFIGURATION */
1017                         if (dev->current_config) {
1018                                 unsigned power;
1019 
1020                                 if (gadget_is_dualspeed(dev->gadget)
1021                                                 && (dev->gadget->speed
1022                                                         == USB_SPEED_HIGH))
1023                                         power = dev->hs_config->bMaxPower;
1024                                 else
1025                                         power = dev->config->bMaxPower;
1026                                 usb_gadget_vbus_draw(dev->gadget, 2 * power);
1027                         }
1028 
1029                 } else {                        /* collect OUT data */
1030                         if ((fd->f_flags & O_NONBLOCK) != 0
1031                                         && !dev->setup_out_ready) {
1032                                 retval = -EAGAIN;
1033                                 goto done;
1034                         }
1035                         spin_unlock_irq (&dev->lock);
1036                         retval = wait_event_interruptible (dev->wait,
1037                                         dev->setup_out_ready != 0);
1038 
1039                         /* FIXME state could change from under us */
1040                         spin_lock_irq (&dev->lock);
1041                         if (retval)
1042                                 goto done;
1043 
1044                         if (dev->state != STATE_DEV_SETUP) {
1045                                 retval = -ECANCELED;
1046                                 goto done;
1047                         }
1048                         dev->state = STATE_DEV_CONNECTED;
1049 
1050                         if (dev->setup_out_error)
1051                                 retval = -EIO;
1052                         else {
1053                                 len = min (len, (size_t)dev->req->actual);
1054 // FIXME don't call this with the spinlock held ...
1055                                 if (copy_to_user (buf, dev->req->buf, len))
1056                                         retval = -EFAULT;
1057                                 else
1058                                         retval = len;
1059                                 clean_req (dev->gadget->ep0, dev->req);
1060                                 /* NOTE userspace can't yet choose to stall */
1061                         }
1062                 }
1063                 goto done;
1064         }
1065 
1066         /* else normal: return event data */
1067         if (len < sizeof dev->event [0]) {
1068                 retval = -EINVAL;
1069                 goto done;
1070         }
1071         len -= len % sizeof (struct usb_gadgetfs_event);
1072         dev->usermode_setup = 1;
1073 
1074 scan:
1075         /* return queued events right away */
1076         if (dev->ev_next != 0) {
1077                 unsigned                i, n;
1078 
1079                 n = len / sizeof (struct usb_gadgetfs_event);
1080                 if (dev->ev_next < n)
1081                         n = dev->ev_next;
1082 
1083                 /* ep0 i/o has special semantics during STATE_DEV_SETUP */
1084                 for (i = 0; i < n; i++) {
1085                         if (dev->event [i].type == GADGETFS_SETUP) {
1086                                 dev->state = STATE_DEV_SETUP;
1087                                 n = i + 1;
1088                                 break;
1089                         }
1090                 }
1091                 spin_unlock_irq (&dev->lock);
1092                 len = n * sizeof (struct usb_gadgetfs_event);
1093                 if (copy_to_user (buf, &dev->event, len))
1094                         retval = -EFAULT;
1095                 else
1096                         retval = len;
1097                 if (len > 0) {
1098                         /* NOTE this doesn't guard against broken drivers;
1099                          * concurrent ep0 readers may lose events.
1100                          */
1101                         spin_lock_irq (&dev->lock);
1102                         if (dev->ev_next > n) {
1103                                 memmove(&dev->event[0], &dev->event[n],
1104                                         sizeof (struct usb_gadgetfs_event)
1105                                                 * (dev->ev_next - n));
1106                         }
1107                         dev->ev_next -= n;
1108                         spin_unlock_irq (&dev->lock);
1109                 }
1110                 return retval;
1111         }
1112         if (fd->f_flags & O_NONBLOCK) {
1113                 retval = -EAGAIN;
1114                 goto done;
1115         }
1116 
1117         switch (state) {
1118         default:
1119                 DBG (dev, "fail %s, state %d\n", __func__, state);
1120                 retval = -ESRCH;
1121                 break;
1122         case STATE_DEV_UNCONNECTED:
1123         case STATE_DEV_CONNECTED:
1124                 spin_unlock_irq (&dev->lock);
1125                 DBG (dev, "%s wait\n", __func__);
1126 
1127                 /* wait for events */
1128                 retval = wait_event_interruptible (dev->wait,
1129                                 dev->ev_next != 0);
1130                 if (retval < 0)
1131                         return retval;
1132                 spin_lock_irq (&dev->lock);
1133                 goto scan;
1134         }
1135 
1136 done:
1137         spin_unlock_irq (&dev->lock);
1138         return retval;
1139 }
1140 
1141 static struct usb_gadgetfs_event *
1142 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1143 {
1144         struct usb_gadgetfs_event       *event;
1145         unsigned                        i;
1146 
1147         switch (type) {
1148         /* these events purge the queue */
1149         case GADGETFS_DISCONNECT:
1150                 if (dev->state == STATE_DEV_SETUP)
1151                         dev->setup_abort = 1;
1152                 // FALL THROUGH
1153         case GADGETFS_CONNECT:
1154                 dev->ev_next = 0;
1155                 break;
1156         case GADGETFS_SETUP:            /* previous request timed out */
1157         case GADGETFS_SUSPEND:          /* same effect */
1158                 /* these events can't be repeated */
1159                 for (i = 0; i != dev->ev_next; i++) {
1160                         if (dev->event [i].type != type)
1161                                 continue;
1162                         DBG(dev, "discard old event[%d] %d\n", i, type);
1163                         dev->ev_next--;
1164                         if (i == dev->ev_next)
1165                                 break;
1166                         /* indices start at zero, for simplicity */
1167                         memmove (&dev->event [i], &dev->event [i + 1],
1168                                 sizeof (struct usb_gadgetfs_event)
1169                                         * (dev->ev_next - i));
1170                 }
1171                 break;
1172         default:
1173                 BUG ();
1174         }
1175         VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1176         event = &dev->event [dev->ev_next++];
1177         BUG_ON (dev->ev_next > N_EVENT);
1178         memset (event, 0, sizeof *event);
1179         event->type = type;
1180         return event;
1181 }
1182 
1183 static ssize_t
1184 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1185 {
1186         struct dev_data         *dev = fd->private_data;
1187         ssize_t                 retval = -ESRCH;
1188 
1189         spin_lock_irq (&dev->lock);
1190 
1191         /* report fd mode change before acting on it */
1192         if (dev->setup_abort) {
1193                 dev->setup_abort = 0;
1194                 retval = -EIDRM;
1195 
1196         /* data and/or status stage for control request */
1197         } else if (dev->state == STATE_DEV_SETUP) {
1198 
1199                 /* IN DATA+STATUS caller makes len <= wLength */
1200                 if (dev->setup_in) {
1201                         retval = setup_req (dev->gadget->ep0, dev->req, len);
1202                         if (retval == 0) {
1203                                 dev->state = STATE_DEV_CONNECTED;
1204                                 spin_unlock_irq (&dev->lock);
1205                                 if (copy_from_user (dev->req->buf, buf, len))
1206                                         retval = -EFAULT;
1207                                 else {
1208                                         if (len < dev->setup_wLength)
1209                                                 dev->req->zero = 1;
1210                                         retval = usb_ep_queue (
1211                                                 dev->gadget->ep0, dev->req,
1212                                                 GFP_KERNEL);
1213                                 }
1214                                 if (retval < 0) {
1215                                         spin_lock_irq (&dev->lock);
1216                                         clean_req (dev->gadget->ep0, dev->req);
1217                                         spin_unlock_irq (&dev->lock);
1218                                 } else
1219                                         retval = len;
1220 
1221                                 return retval;
1222                         }
1223 
1224                 /* can stall some OUT transfers */
1225                 } else if (dev->setup_can_stall) {
1226                         VDEBUG(dev, "ep0out stall\n");
1227                         (void) usb_ep_set_halt (dev->gadget->ep0);
1228                         retval = -EL2HLT;
1229                         dev->state = STATE_DEV_CONNECTED;
1230                 } else {
1231                         DBG(dev, "bogus ep0out stall!\n");
1232                 }
1233         } else
1234                 DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1235 
1236         spin_unlock_irq (&dev->lock);
1237         return retval;
1238 }
1239 
1240 static int
1241 ep0_fasync (int f, struct file *fd, int on)
1242 {
1243         struct dev_data         *dev = fd->private_data;
1244         // caller must F_SETOWN before signal delivery happens
1245         VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1246         return fasync_helper (f, fd, on, &dev->fasync);
1247 }
1248 
1249 static struct usb_gadget_driver gadgetfs_driver;
1250 
1251 static int
1252 dev_release (struct inode *inode, struct file *fd)
1253 {
1254         struct dev_data         *dev = fd->private_data;
1255 
1256         /* closing ep0 === shutdown all */
1257 
1258         usb_gadget_unregister_driver (&gadgetfs_driver);
1259 
1260         /* at this point "good" hardware has disconnected the
1261          * device from USB; the host won't see it any more.
1262          * alternatively, all host requests will time out.
1263          */
1264 
1265         kfree (dev->buf);
1266         dev->buf = NULL;
1267 
1268         /* other endpoints were all decoupled from this device */
1269         spin_lock_irq(&dev->lock);
1270         dev->state = STATE_DEV_DISABLED;
1271         spin_unlock_irq(&dev->lock);
1272 
1273         put_dev (dev);
1274         return 0;
1275 }
1276 
1277 static unsigned int
1278 ep0_poll (struct file *fd, poll_table *wait)
1279 {
1280        struct dev_data         *dev = fd->private_data;
1281        int                     mask = 0;
1282 
1283        poll_wait(fd, &dev->wait, wait);
1284 
1285        spin_lock_irq (&dev->lock);
1286 
1287        /* report fd mode change before acting on it */
1288        if (dev->setup_abort) {
1289                dev->setup_abort = 0;
1290                mask = POLLHUP;
1291                goto out;
1292        }
1293 
1294        if (dev->state == STATE_DEV_SETUP) {
1295                if (dev->setup_in || dev->setup_can_stall)
1296                        mask = POLLOUT;
1297        } else {
1298                if (dev->ev_next != 0)
1299                        mask = POLLIN;
1300        }
1301 out:
1302        spin_unlock_irq(&dev->lock);
1303        return mask;
1304 }
1305 
1306 static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1307 {
1308         struct dev_data         *dev = fd->private_data;
1309         struct usb_gadget       *gadget = dev->gadget;
1310         long ret = -ENOTTY;
1311 
1312         if (gadget->ops->ioctl)
1313                 ret = gadget->ops->ioctl (gadget, code, value);
1314 
1315         return ret;
1316 }
1317 
1318 /* used after device configuration */
1319 static const struct file_operations ep0_io_operations = {
1320         .owner =        THIS_MODULE,
1321         .llseek =       no_llseek,
1322 
1323         .read =         ep0_read,
1324         .write =        ep0_write,
1325         .fasync =       ep0_fasync,
1326         .poll =         ep0_poll,
1327         .unlocked_ioctl =       dev_ioctl,
1328         .release =      dev_release,
1329 };
1330 
1331 /*----------------------------------------------------------------------*/
1332 
1333 /* The in-kernel gadget driver handles most ep0 issues, in particular
1334  * enumerating the single configuration (as provided from user space).
1335  *
1336  * Unrecognized ep0 requests may be handled in user space.
1337  */
1338 
1339 static void make_qualifier (struct dev_data *dev)
1340 {
1341         struct usb_qualifier_descriptor         qual;
1342         struct usb_device_descriptor            *desc;
1343 
1344         qual.bLength = sizeof qual;
1345         qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1346         qual.bcdUSB = cpu_to_le16 (0x0200);
1347 
1348         desc = dev->dev;
1349         qual.bDeviceClass = desc->bDeviceClass;
1350         qual.bDeviceSubClass = desc->bDeviceSubClass;
1351         qual.bDeviceProtocol = desc->bDeviceProtocol;
1352 
1353         /* assumes ep0 uses the same value for both speeds ... */
1354         qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1355 
1356         qual.bNumConfigurations = 1;
1357         qual.bRESERVED = 0;
1358 
1359         memcpy (dev->rbuf, &qual, sizeof qual);
1360 }
1361 
1362 static int
1363 config_buf (struct dev_data *dev, u8 type, unsigned index)
1364 {
1365         int             len;
1366         int             hs = 0;
1367 
1368         /* only one configuration */
1369         if (index > 0)
1370                 return -EINVAL;
1371 
1372         if (gadget_is_dualspeed(dev->gadget)) {
1373                 hs = (dev->gadget->speed == USB_SPEED_HIGH);
1374                 if (type == USB_DT_OTHER_SPEED_CONFIG)
1375                         hs = !hs;
1376         }
1377         if (hs) {
1378                 dev->req->buf = dev->hs_config;
1379                 len = le16_to_cpu(dev->hs_config->wTotalLength);
1380         } else {
1381                 dev->req->buf = dev->config;
1382                 len = le16_to_cpu(dev->config->wTotalLength);
1383         }
1384         ((u8 *)dev->req->buf) [1] = type;
1385         return len;
1386 }
1387 
1388 static int
1389 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1390 {
1391         struct dev_data                 *dev = get_gadget_data (gadget);
1392         struct usb_request              *req = dev->req;
1393         int                             value = -EOPNOTSUPP;
1394         struct usb_gadgetfs_event       *event;
1395         u16                             w_value = le16_to_cpu(ctrl->wValue);
1396         u16                             w_length = le16_to_cpu(ctrl->wLength);
1397 
1398         spin_lock (&dev->lock);
1399         dev->setup_abort = 0;
1400         if (dev->state == STATE_DEV_UNCONNECTED) {
1401                 if (gadget_is_dualspeed(gadget)
1402                                 && gadget->speed == USB_SPEED_HIGH
1403                                 && dev->hs_config == NULL) {
1404                         spin_unlock(&dev->lock);
1405                         ERROR (dev, "no high speed config??\n");
1406                         return -EINVAL;
1407                 }
1408 
1409                 dev->state = STATE_DEV_CONNECTED;
1410 
1411                 INFO (dev, "connected\n");
1412                 event = next_event (dev, GADGETFS_CONNECT);
1413                 event->u.speed = gadget->speed;
1414                 ep0_readable (dev);
1415 
1416         /* host may have given up waiting for response.  we can miss control
1417          * requests handled lower down (device/endpoint status and features);
1418          * then ep0_{read,write} will report the wrong status. controller
1419          * driver will have aborted pending i/o.
1420          */
1421         } else if (dev->state == STATE_DEV_SETUP)
1422                 dev->setup_abort = 1;
1423 
1424         req->buf = dev->rbuf;
1425         req->context = NULL;
1426         value = -EOPNOTSUPP;
1427         switch (ctrl->bRequest) {
1428 
1429         case USB_REQ_GET_DESCRIPTOR:
1430                 if (ctrl->bRequestType != USB_DIR_IN)
1431                         goto unrecognized;
1432                 switch (w_value >> 8) {
1433 
1434                 case USB_DT_DEVICE:
1435                         value = min (w_length, (u16) sizeof *dev->dev);
1436                         dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1437                         req->buf = dev->dev;
1438                         break;
1439                 case USB_DT_DEVICE_QUALIFIER:
1440                         if (!dev->hs_config)
1441                                 break;
1442                         value = min (w_length, (u16)
1443                                 sizeof (struct usb_qualifier_descriptor));
1444                         make_qualifier (dev);
1445                         break;
1446                 case USB_DT_OTHER_SPEED_CONFIG:
1447                         // FALLTHROUGH
1448                 case USB_DT_CONFIG:
1449                         value = config_buf (dev,
1450                                         w_value >> 8,
1451                                         w_value & 0xff);
1452                         if (value >= 0)
1453                                 value = min (w_length, (u16) value);
1454                         break;
1455                 case USB_DT_STRING:
1456                         goto unrecognized;
1457 
1458                 default:                // all others are errors
1459                         break;
1460                 }
1461                 break;
1462 
1463         /* currently one config, two speeds */
1464         case USB_REQ_SET_CONFIGURATION:
1465                 if (ctrl->bRequestType != 0)
1466                         goto unrecognized;
1467                 if (0 == (u8) w_value) {
1468                         value = 0;
1469                         dev->current_config = 0;
1470                         usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1471                         // user mode expected to disable endpoints
1472                 } else {
1473                         u8      config, power;
1474 
1475                         if (gadget_is_dualspeed(gadget)
1476                                         && gadget->speed == USB_SPEED_HIGH) {
1477                                 config = dev->hs_config->bConfigurationValue;
1478                                 power = dev->hs_config->bMaxPower;
1479                         } else {
1480                                 config = dev->config->bConfigurationValue;
1481                                 power = dev->config->bMaxPower;
1482                         }
1483 
1484                         if (config == (u8) w_value) {
1485                                 value = 0;
1486                                 dev->current_config = config;
1487                                 usb_gadget_vbus_draw(gadget, 2 * power);
1488                         }
1489                 }
1490 
1491                 /* report SET_CONFIGURATION like any other control request,
1492                  * except that usermode may not stall this.  the next
1493                  * request mustn't be allowed start until this finishes:
1494                  * endpoints and threads set up, etc.
1495                  *
1496                  * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1497                  * has bad/racey automagic that prevents synchronizing here.
1498                  * even kernel mode drivers often miss them.
1499                  */
1500                 if (value == 0) {
1501                         INFO (dev, "configuration #%d\n", dev->current_config);
1502                         usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1503                         if (dev->usermode_setup) {
1504                                 dev->setup_can_stall = 0;
1505                                 goto delegate;
1506                         }
1507                 }
1508                 break;
1509 
1510 #ifndef CONFIG_USB_PXA25X
1511         /* PXA automagically handles this request too */
1512         case USB_REQ_GET_CONFIGURATION:
1513                 if (ctrl->bRequestType != 0x80)
1514                         goto unrecognized;
1515                 *(u8 *)req->buf = dev->current_config;
1516                 value = min (w_length, (u16) 1);
1517                 break;
1518 #endif
1519 
1520         default:
1521 unrecognized:
1522                 VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1523                         dev->usermode_setup ? "delegate" : "fail",
1524                         ctrl->bRequestType, ctrl->bRequest,
1525                         w_value, le16_to_cpu(ctrl->wIndex), w_length);
1526 
1527                 /* if there's an ep0 reader, don't stall */
1528                 if (dev->usermode_setup) {
1529                         dev->setup_can_stall = 1;
1530 delegate:
1531                         dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1532                                                 ? 1 : 0;
1533                         dev->setup_wLength = w_length;
1534                         dev->setup_out_ready = 0;
1535                         dev->setup_out_error = 0;
1536                         value = 0;
1537 
1538                         /* read DATA stage for OUT right away */
1539                         if (unlikely (!dev->setup_in && w_length)) {
1540                                 value = setup_req (gadget->ep0, dev->req,
1541                                                         w_length);
1542                                 if (value < 0)
1543                                         break;
1544                                 value = usb_ep_queue (gadget->ep0, dev->req,
1545                                                         GFP_ATOMIC);
1546                                 if (value < 0) {
1547                                         clean_req (gadget->ep0, dev->req);
1548                                         break;
1549                                 }
1550 
1551                                 /* we can't currently stall these */
1552                                 dev->setup_can_stall = 0;
1553                         }
1554 
1555                         /* state changes when reader collects event */
1556                         event = next_event (dev, GADGETFS_SETUP);
1557                         event->u.setup = *ctrl;
1558                         ep0_readable (dev);
1559                         spin_unlock (&dev->lock);
1560                         return 0;
1561                 }
1562         }
1563 
1564         /* proceed with data transfer and status phases? */
1565         if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1566                 req->length = value;
1567                 req->zero = value < w_length;
1568                 value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
1569                 if (value < 0) {
1570                         DBG (dev, "ep_queue --> %d\n", value);
1571                         req->status = 0;
1572                 }
1573         }
1574 
1575         /* device stalls when value < 0 */
1576         spin_unlock (&dev->lock);
1577         return value;
1578 }
1579 
1580 static void destroy_ep_files (struct dev_data *dev)
1581 {
1582         DBG (dev, "%s %d\n", __func__, dev->state);
1583 
1584         /* dev->state must prevent interference */
1585         spin_lock_irq (&dev->lock);
1586         while (!list_empty(&dev->epfiles)) {
1587                 struct ep_data  *ep;
1588                 struct inode    *parent;
1589                 struct dentry   *dentry;
1590 
1591                 /* break link to FS */
1592                 ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1593                 list_del_init (&ep->epfiles);
1594                 dentry = ep->dentry;
1595                 ep->dentry = NULL;
1596                 parent = dentry->d_parent->d_inode;
1597 
1598                 /* break link to controller */
1599                 if (ep->state == STATE_EP_ENABLED)
1600                         (void) usb_ep_disable (ep->ep);
1601                 ep->state = STATE_EP_UNBOUND;
1602                 usb_ep_free_request (ep->ep, ep->req);
1603                 ep->ep = NULL;
1604                 wake_up (&ep->wait);
1605                 put_ep (ep);
1606 
1607                 spin_unlock_irq (&dev->lock);
1608 
1609                 /* break link to dcache */
1610                 mutex_lock (&parent->i_mutex);
1611                 d_delete (dentry);
1612                 dput (dentry);
1613                 mutex_unlock (&parent->i_mutex);
1614 
1615                 spin_lock_irq (&dev->lock);
1616         }
1617         spin_unlock_irq (&dev->lock);
1618 }
1619 
1620 
1621 static struct inode *
1622 gadgetfs_create_file (struct super_block *sb, char const *name,
1623                 void *data, const struct file_operations *fops,
1624                 struct dentry **dentry_p);
1625 
1626 static int activate_ep_files (struct dev_data *dev)
1627 {
1628         struct usb_ep   *ep;
1629         struct ep_data  *data;
1630 
1631         gadget_for_each_ep (ep, dev->gadget) {
1632 
1633                 data = kzalloc(sizeof(*data), GFP_KERNEL);
1634                 if (!data)
1635                         goto enomem0;
1636                 data->state = STATE_EP_DISABLED;
1637                 mutex_init(&data->lock);
1638                 init_waitqueue_head (&data->wait);
1639 
1640                 strncpy (data->name, ep->name, sizeof (data->name) - 1);
1641                 atomic_set (&data->count, 1);
1642                 data->dev = dev;
1643                 get_dev (dev);
1644 
1645                 data->ep = ep;
1646                 ep->driver_data = data;
1647 
1648                 data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1649                 if (!data->req)
1650                         goto enomem1;
1651 
1652                 data->inode = gadgetfs_create_file (dev->sb, data->name,
1653                                 data, &ep_config_operations,
1654                                 &data->dentry);
1655                 if (!data->inode)
1656                         goto enomem2;
1657                 list_add_tail (&data->epfiles, &dev->epfiles);
1658         }
1659         return 0;
1660 
1661 enomem2:
1662         usb_ep_free_request (ep, data->req);
1663 enomem1:
1664         put_dev (dev);
1665         kfree (data);
1666 enomem0:
1667         DBG (dev, "%s enomem\n", __func__);
1668         destroy_ep_files (dev);
1669         return -ENOMEM;
1670 }
1671 
1672 static void
1673 gadgetfs_unbind (struct usb_gadget *gadget)
1674 {
1675         struct dev_data         *dev = get_gadget_data (gadget);
1676 
1677         DBG (dev, "%s\n", __func__);
1678 
1679         spin_lock_irq (&dev->lock);
1680         dev->state = STATE_DEV_UNBOUND;
1681         spin_unlock_irq (&dev->lock);
1682 
1683         destroy_ep_files (dev);
1684         gadget->ep0->driver_data = NULL;
1685         set_gadget_data (gadget, NULL);
1686 
1687         /* we've already been disconnected ... no i/o is active */
1688         if (dev->req)
1689                 usb_ep_free_request (gadget->ep0, dev->req);
1690         DBG (dev, "%s done\n", __func__);
1691         put_dev (dev);
1692 }
1693 
1694 static struct dev_data          *the_device;
1695 
1696 static int gadgetfs_bind(struct usb_gadget *gadget,
1697                 struct usb_gadget_driver *driver)
1698 {
1699         struct dev_data         *dev = the_device;
1700 
1701         if (!dev)
1702                 return -ESRCH;
1703         if (0 != strcmp (CHIP, gadget->name)) {
1704                 pr_err("%s expected %s controller not %s\n",
1705                         shortname, CHIP, gadget->name);
1706                 return -ENODEV;
1707         }
1708 
1709         set_gadget_data (gadget, dev);
1710         dev->gadget = gadget;
1711         gadget->ep0->driver_data = dev;
1712 
1713         /* preallocate control response and buffer */
1714         dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1715         if (!dev->req)
1716                 goto enomem;
1717         dev->req->context = NULL;
1718         dev->req->complete = epio_complete;
1719 
1720         if (activate_ep_files (dev) < 0)
1721                 goto enomem;
1722 
1723         INFO (dev, "bound to %s driver\n", gadget->name);
1724         spin_lock_irq(&dev->lock);
1725         dev->state = STATE_DEV_UNCONNECTED;
1726         spin_unlock_irq(&dev->lock);
1727         get_dev (dev);
1728         return 0;
1729 
1730 enomem:
1731         gadgetfs_unbind (gadget);
1732         return -ENOMEM;
1733 }
1734 
1735 static void
1736 gadgetfs_disconnect (struct usb_gadget *gadget)
1737 {
1738         struct dev_data         *dev = get_gadget_data (gadget);
1739         unsigned long           flags;
1740 
1741         spin_lock_irqsave (&dev->lock, flags);
1742         if (dev->state == STATE_DEV_UNCONNECTED)
1743                 goto exit;
1744         dev->state = STATE_DEV_UNCONNECTED;
1745 
1746         INFO (dev, "disconnected\n");
1747         next_event (dev, GADGETFS_DISCONNECT);
1748         ep0_readable (dev);
1749 exit:
1750         spin_unlock_irqrestore (&dev->lock, flags);
1751 }
1752 
1753 static void
1754 gadgetfs_suspend (struct usb_gadget *gadget)
1755 {
1756         struct dev_data         *dev = get_gadget_data (gadget);
1757 
1758         INFO (dev, "suspended from state %d\n", dev->state);
1759         spin_lock (&dev->lock);
1760         switch (dev->state) {
1761         case STATE_DEV_SETUP:           // VERY odd... host died??
1762         case STATE_DEV_CONNECTED:
1763         case STATE_DEV_UNCONNECTED:
1764                 next_event (dev, GADGETFS_SUSPEND);
1765                 ep0_readable (dev);
1766                 /* FALLTHROUGH */
1767         default:
1768                 break;
1769         }
1770         spin_unlock (&dev->lock);
1771 }
1772 
1773 static struct usb_gadget_driver gadgetfs_driver = {
1774         .function       = (char *) driver_desc,
1775         .bind           = gadgetfs_bind,
1776         .unbind         = gadgetfs_unbind,
1777         .setup          = gadgetfs_setup,
1778         .disconnect     = gadgetfs_disconnect,
1779         .suspend        = gadgetfs_suspend,
1780 
1781         .driver = {
1782                 .name           = (char *) shortname,
1783         },
1784 };
1785 
1786 /*----------------------------------------------------------------------*/
1787 
1788 static void gadgetfs_nop(struct usb_gadget *arg) { }
1789 
1790 static int gadgetfs_probe(struct usb_gadget *gadget,
1791                 struct usb_gadget_driver *driver)
1792 {
1793         CHIP = gadget->name;
1794         return -EISNAM;
1795 }
1796 
1797 static struct usb_gadget_driver probe_driver = {
1798         .max_speed      = USB_SPEED_HIGH,
1799         .bind           = gadgetfs_probe,
1800         .unbind         = gadgetfs_nop,
1801         .setup          = (void *)gadgetfs_nop,
1802         .disconnect     = gadgetfs_nop,
1803         .driver = {
1804                 .name           = "nop",
1805         },
1806 };
1807 
1808 
1809 /* DEVICE INITIALIZATION
1810  *
1811  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1812  *     status = write (fd, descriptors, sizeof descriptors)
1813  *
1814  * That write establishes the device configuration, so the kernel can
1815  * bind to the controller ... guaranteeing it can handle enumeration
1816  * at all necessary speeds.  Descriptor order is:
1817  *
1818  * . message tag (u32, host order) ... for now, must be zero; it
1819  *      would change to support features like multi-config devices
1820  * . full/low speed config ... all wTotalLength bytes (with interface,
1821  *      class, altsetting, endpoint, and other descriptors)
1822  * . high speed config ... all descriptors, for high speed operation;
1823  *      this one's optional except for high-speed hardware
1824  * . device descriptor
1825  *
1826  * Endpoints are not yet enabled. Drivers must wait until device
1827  * configuration and interface altsetting changes create
1828  * the need to configure (or unconfigure) them.
1829  *
1830  * After initialization, the device stays active for as long as that
1831  * $CHIP file is open.  Events must then be read from that descriptor,
1832  * such as configuration notifications.
1833  */
1834 
1835 static int is_valid_config (struct usb_config_descriptor *config)
1836 {
1837         return config->bDescriptorType == USB_DT_CONFIG
1838                 && config->bLength == USB_DT_CONFIG_SIZE
1839                 && config->bConfigurationValue != 0
1840                 && (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1841                 && (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1842         /* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1843         /* FIXME check lengths: walk to end */
1844 }
1845 
1846 static ssize_t
1847 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1848 {
1849         struct dev_data         *dev = fd->private_data;
1850         ssize_t                 value = len, length = len;
1851         unsigned                total;
1852         u32                     tag;
1853         char                    *kbuf;
1854 
1855         if (len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4))
1856                 return -EINVAL;
1857 
1858         /* we might need to change message format someday */
1859         if (copy_from_user (&tag, buf, 4))
1860                 return -EFAULT;
1861         if (tag != 0)
1862                 return -EINVAL;
1863         buf += 4;
1864         length -= 4;
1865 
1866         kbuf = memdup_user(buf, length);
1867         if (IS_ERR(kbuf))
1868                 return PTR_ERR(kbuf);
1869 
1870         spin_lock_irq (&dev->lock);
1871         value = -EINVAL;
1872         if (dev->buf)
1873                 goto fail;
1874         dev->buf = kbuf;
1875 
1876         /* full or low speed config */
1877         dev->config = (void *) kbuf;
1878         total = le16_to_cpu(dev->config->wTotalLength);
1879         if (!is_valid_config (dev->config) || total >= length)
1880                 goto fail;
1881         kbuf += total;
1882         length -= total;
1883 
1884         /* optional high speed config */
1885         if (kbuf [1] == USB_DT_CONFIG) {
1886                 dev->hs_config = (void *) kbuf;
1887                 total = le16_to_cpu(dev->hs_config->wTotalLength);
1888                 if (!is_valid_config (dev->hs_config) || total >= length)
1889                         goto fail;
1890                 kbuf += total;
1891                 length -= total;
1892         }
1893 
1894         /* could support multiple configs, using another encoding! */
1895 
1896         /* device descriptor (tweaked for paranoia) */
1897         if (length != USB_DT_DEVICE_SIZE)
1898                 goto fail;
1899         dev->dev = (void *)kbuf;
1900         if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1901                         || dev->dev->bDescriptorType != USB_DT_DEVICE
1902                         || dev->dev->bNumConfigurations != 1)
1903                 goto fail;
1904         dev->dev->bNumConfigurations = 1;
1905         dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1906 
1907         /* triggers gadgetfs_bind(); then we can enumerate. */
1908         spin_unlock_irq (&dev->lock);
1909         if (dev->hs_config)
1910                 gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1911         else
1912                 gadgetfs_driver.max_speed = USB_SPEED_FULL;
1913 
1914         value = usb_gadget_probe_driver(&gadgetfs_driver);
1915         if (value != 0) {
1916                 kfree (dev->buf);
1917                 dev->buf = NULL;
1918         } else {
1919                 /* at this point "good" hardware has for the first time
1920                  * let the USB the host see us.  alternatively, if users
1921                  * unplug/replug that will clear all the error state.
1922                  *
1923                  * note:  everything running before here was guaranteed
1924                  * to choke driver model style diagnostics.  from here
1925                  * on, they can work ... except in cleanup paths that
1926                  * kick in after the ep0 descriptor is closed.
1927                  */
1928                 fd->f_op = &ep0_io_operations;
1929                 value = len;
1930         }
1931         return value;
1932 
1933 fail:
1934         spin_unlock_irq (&dev->lock);
1935         pr_debug ("%s: %s fail %Zd, %p\n", shortname, __func__, value, dev);
1936         kfree (dev->buf);
1937         dev->buf = NULL;
1938         return value;
1939 }
1940 
1941 static int
1942 dev_open (struct inode *inode, struct file *fd)
1943 {
1944         struct dev_data         *dev = inode->i_private;
1945         int                     value = -EBUSY;
1946 
1947         spin_lock_irq(&dev->lock);
1948         if (dev->state == STATE_DEV_DISABLED) {
1949                 dev->ev_next = 0;
1950                 dev->state = STATE_DEV_OPENED;
1951                 fd->private_data = dev;
1952                 get_dev (dev);
1953                 value = 0;
1954         }
1955         spin_unlock_irq(&dev->lock);
1956         return value;
1957 }
1958 
1959 static const struct file_operations dev_init_operations = {
1960         .llseek =       no_llseek,
1961 
1962         .open =         dev_open,
1963         .write =        dev_config,
1964         .fasync =       ep0_fasync,
1965         .unlocked_ioctl = dev_ioctl,
1966         .release =      dev_release,
1967 };
1968 
1969 /*----------------------------------------------------------------------*/
1970 
1971 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1972  *
1973  * Mounting the filesystem creates a controller file, used first for
1974  * device configuration then later for event monitoring.
1975  */
1976 
1977 
1978 /* FIXME PAM etc could set this security policy without mount options
1979  * if epfiles inherited ownership and permissons from ep0 ...
1980  */
1981 
1982 static unsigned default_uid;
1983 static unsigned default_gid;
1984 static unsigned default_perm = S_IRUSR | S_IWUSR;
1985 
1986 module_param (default_uid, uint, 0644);
1987 module_param (default_gid, uint, 0644);
1988 module_param (default_perm, uint, 0644);
1989 
1990 
1991 static struct inode *
1992 gadgetfs_make_inode (struct super_block *sb,
1993                 void *data, const struct file_operations *fops,
1994                 int mode)
1995 {
1996         struct inode *inode = new_inode (sb);
1997 
1998         if (inode) {
1999                 inode->i_ino = get_next_ino();
2000                 inode->i_mode = mode;
2001                 inode->i_uid = make_kuid(&init_user_ns, default_uid);
2002                 inode->i_gid = make_kgid(&init_user_ns, default_gid);
2003                 inode->i_atime = inode->i_mtime = inode->i_ctime
2004                                 = CURRENT_TIME;
2005                 inode->i_private = data;
2006                 inode->i_fop = fops;
2007         }
2008         return inode;
2009 }
2010 
2011 /* creates in fs root directory, so non-renamable and non-linkable.
2012  * so inode and dentry are paired, until device reconfig.
2013  */
2014 static struct inode *
2015 gadgetfs_create_file (struct super_block *sb, char const *name,
2016                 void *data, const struct file_operations *fops,
2017                 struct dentry **dentry_p)
2018 {
2019         struct dentry   *dentry;
2020         struct inode    *inode;
2021 
2022         dentry = d_alloc_name(sb->s_root, name);
2023         if (!dentry)
2024                 return NULL;
2025 
2026         inode = gadgetfs_make_inode (sb, data, fops,
2027                         S_IFREG | (default_perm & S_IRWXUGO));
2028         if (!inode) {
2029                 dput(dentry);
2030                 return NULL;
2031         }
2032         d_add (dentry, inode);
2033         *dentry_p = dentry;
2034         return inode;
2035 }
2036 
2037 static const struct super_operations gadget_fs_operations = {
2038         .statfs =       simple_statfs,
2039         .drop_inode =   generic_delete_inode,
2040 };
2041 
2042 static int
2043 gadgetfs_fill_super (struct super_block *sb, void *opts, int silent)
2044 {
2045         struct inode    *inode;
2046         struct dev_data *dev;
2047 
2048         if (the_device)
2049                 return -ESRCH;
2050 
2051         /* fake probe to determine $CHIP */
2052         CHIP = NULL;
2053         usb_gadget_probe_driver(&probe_driver);
2054         if (!CHIP)
2055                 return -ENODEV;
2056 
2057         /* superblock */
2058         sb->s_blocksize = PAGE_CACHE_SIZE;
2059         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2060         sb->s_magic = GADGETFS_MAGIC;
2061         sb->s_op = &gadget_fs_operations;
2062         sb->s_time_gran = 1;
2063 
2064         /* root inode */
2065         inode = gadgetfs_make_inode (sb,
2066                         NULL, &simple_dir_operations,
2067                         S_IFDIR | S_IRUGO | S_IXUGO);
2068         if (!inode)
2069                 goto Enomem;
2070         inode->i_op = &simple_dir_inode_operations;
2071         if (!(sb->s_root = d_make_root (inode)))
2072                 goto Enomem;
2073 
2074         /* the ep0 file is named after the controller we expect;
2075          * user mode code can use it for sanity checks, like we do.
2076          */
2077         dev = dev_new ();
2078         if (!dev)
2079                 goto Enomem;
2080 
2081         dev->sb = sb;
2082         if (!gadgetfs_create_file (sb, CHIP,
2083                                 dev, &dev_init_operations,
2084                                 &dev->dentry)) {
2085                 put_dev(dev);
2086                 goto Enomem;
2087         }
2088 
2089         /* other endpoint files are available after hardware setup,
2090          * from binding to a controller.
2091          */
2092         the_device = dev;
2093         return 0;
2094 
2095 Enomem:
2096         return -ENOMEM;
2097 }
2098 
2099 /* "mount -t gadgetfs path /dev/gadget" ends up here */
2100 static struct dentry *
2101 gadgetfs_mount (struct file_system_type *t, int flags,
2102                 const char *path, void *opts)
2103 {
2104         return mount_single (t, flags, opts, gadgetfs_fill_super);
2105 }
2106 
2107 static void
2108 gadgetfs_kill_sb (struct super_block *sb)
2109 {
2110         kill_litter_super (sb);
2111         if (the_device) {
2112                 put_dev (the_device);
2113                 the_device = NULL;
2114         }
2115 }
2116 
2117 /*----------------------------------------------------------------------*/
2118 
2119 static struct file_system_type gadgetfs_type = {
2120         .owner          = THIS_MODULE,
2121         .name           = shortname,
2122         .mount          = gadgetfs_mount,
2123         .kill_sb        = gadgetfs_kill_sb,
2124 };
2125 MODULE_ALIAS_FS("gadgetfs");
2126 
2127 /*----------------------------------------------------------------------*/
2128 
2129 static int __init init (void)
2130 {
2131         int status;
2132 
2133         status = register_filesystem (&gadgetfs_type);
2134         if (status == 0)
2135                 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2136                         shortname, driver_desc);
2137         return status;
2138 }
2139 module_init (init);
2140 
2141 static void __exit cleanup (void)
2142 {
2143         pr_debug ("unregister %s\n", shortname);
2144         unregister_filesystem (&gadgetfs_type);
2145 }
2146 module_exit (cleanup);
2147 
2148 

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