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
get_dev(struct dev_data * data)152 static inline void get_dev (struct dev_data *data)
153 {
154 refcount_inc (&data->count);
155 }
156
put_dev(struct dev_data * data)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
dev_new(void)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
get_ep(struct ep_data * data)207 static inline void get_ep (struct ep_data *data)
208 {
209 refcount_inc (&data->count);
210 }
211
put_ep(struct ep_data * data)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 static DEFINE_MUTEX(sb_mutex); /* Serialize superblock operations */
233
234 /*----------------------------------------------------------------------*/
235
236 /* NOTE: don't use dev_printk calls before binding to the gadget
237 * at the end of ep0 configuration, or after unbind.
238 */
239
240 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
241 #define xprintk(d,level,fmt,args...) \
242 printk(level "%s: " fmt , shortname , ## args)
243
244 #ifdef DEBUG
245 #define DBG(dev,fmt,args...) \
246 xprintk(dev , KERN_DEBUG , fmt , ## args)
247 #else
248 #define DBG(dev,fmt,args...) \
249 do { } while (0)
250 #endif /* DEBUG */
251
252 #ifdef VERBOSE_DEBUG
253 #define VDEBUG DBG
254 #else
255 #define VDEBUG(dev,fmt,args...) \
256 do { } while (0)
257 #endif /* DEBUG */
258
259 #define ERROR(dev,fmt,args...) \
260 xprintk(dev , KERN_ERR , fmt , ## args)
261 #define INFO(dev,fmt,args...) \
262 xprintk(dev , KERN_INFO , fmt , ## args)
263
264
265 /*----------------------------------------------------------------------*/
266
267 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
268 *
269 * After opening, configure non-control endpoints. Then use normal
270 * stream read() and write() requests; and maybe ioctl() to get more
271 * precise FIFO status when recovering from cancellation.
272 */
273
epio_complete(struct usb_ep * ep,struct usb_request * req)274 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
275 {
276 struct ep_data *epdata = ep->driver_data;
277
278 if (!req->context)
279 return;
280 if (req->status)
281 epdata->status = req->status;
282 else
283 epdata->status = req->actual;
284 complete ((struct completion *)req->context);
285 }
286
287 /* tasklock endpoint, returning when it's connected.
288 * still need dev->lock to use epdata->ep.
289 */
290 static int
get_ready_ep(unsigned f_flags,struct ep_data * epdata,bool is_write)291 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
292 {
293 int val;
294
295 if (f_flags & O_NONBLOCK) {
296 if (!mutex_trylock(&epdata->lock))
297 goto nonblock;
298 if (epdata->state != STATE_EP_ENABLED &&
299 (!is_write || epdata->state != STATE_EP_READY)) {
300 mutex_unlock(&epdata->lock);
301 nonblock:
302 val = -EAGAIN;
303 } else
304 val = 0;
305 return val;
306 }
307
308 val = mutex_lock_interruptible(&epdata->lock);
309 if (val < 0)
310 return val;
311
312 switch (epdata->state) {
313 case STATE_EP_ENABLED:
314 return 0;
315 case STATE_EP_READY: /* not configured yet */
316 if (is_write)
317 return 0;
318 fallthrough;
319 case STATE_EP_UNBOUND: /* clean disconnect */
320 break;
321 // case STATE_EP_DISABLED: /* "can't happen" */
322 default: /* error! */
323 pr_debug ("%s: ep %p not available, state %d\n",
324 shortname, epdata, epdata->state);
325 }
326 mutex_unlock(&epdata->lock);
327 return -ENODEV;
328 }
329
330 static ssize_t
ep_io(struct ep_data * epdata,void * buf,unsigned len)331 ep_io (struct ep_data *epdata, void *buf, unsigned len)
332 {
333 DECLARE_COMPLETION_ONSTACK (done);
334 int value;
335
336 spin_lock_irq (&epdata->dev->lock);
337 if (likely (epdata->ep != NULL)) {
338 struct usb_request *req = epdata->req;
339
340 req->context = &done;
341 req->complete = epio_complete;
342 req->buf = buf;
343 req->length = len;
344 value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
345 } else
346 value = -ENODEV;
347 spin_unlock_irq (&epdata->dev->lock);
348
349 if (likely (value == 0)) {
350 value = wait_for_completion_interruptible(&done);
351 if (value != 0) {
352 spin_lock_irq (&epdata->dev->lock);
353 if (likely (epdata->ep != NULL)) {
354 DBG (epdata->dev, "%s i/o interrupted\n",
355 epdata->name);
356 usb_ep_dequeue (epdata->ep, epdata->req);
357 spin_unlock_irq (&epdata->dev->lock);
358
359 wait_for_completion(&done);
360 if (epdata->status == -ECONNRESET)
361 epdata->status = -EINTR;
362 } else {
363 spin_unlock_irq (&epdata->dev->lock);
364
365 DBG (epdata->dev, "endpoint gone\n");
366 epdata->status = -ENODEV;
367 }
368 }
369 return epdata->status;
370 }
371 return value;
372 }
373
374 static int
ep_release(struct inode * inode,struct file * fd)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
ep_ioctl(struct file * fd,unsigned code,unsigned long value)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
ep_aio_cancel(struct kiocb * iocb)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
ep_user_copy_worker(struct work_struct * work)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
ep_aio_complete(struct usb_ep * ep,struct usb_request * req)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
ep_aio(struct kiocb * iocb,struct kiocb_priv * priv,struct ep_data * epdata,char * buf,size_t len)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
ep_read_iter(struct kiocb * iocb,struct iov_iter * to)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
ep_write_iter(struct kiocb * iocb,struct iov_iter * from)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
ep_config(struct ep_data * data,const char * buf,size_t len)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
ep_open(struct inode * inode,struct file * fd)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
ep0_readable(struct dev_data * dev)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
clean_req(struct usb_ep * ep,struct usb_request * req)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
ep0_complete(struct usb_ep * ep,struct usb_request * req)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
setup_req(struct usb_ep * ep,struct usb_request * req,u16 len)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
ep0_read(struct file * fd,char __user * buf,size_t len,loff_t * ptr)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 *
next_event(struct dev_data * dev,enum usb_gadgetfs_event_type type)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
ep0_write(struct file * fd,const char __user * buf,size_t len,loff_t * ptr)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
ep0_fasync(int f,struct file * fd,int on)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
dev_release(struct inode * inode,struct file * fd)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
ep0_poll(struct file * fd,poll_table * wait)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
dev_ioctl(struct file * fd,unsigned code,unsigned long value)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
make_qualifier(struct dev_data * dev)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
config_buf(struct dev_data * dev,u8 type,unsigned index)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
gadgetfs_setup(struct usb_gadget * gadget,const struct usb_ctrlrequest * ctrl)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
destroy_ep_files(struct dev_data * dev)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
activate_ep_files(struct dev_data * dev)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
gadgetfs_unbind(struct usb_gadget * gadget)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
gadgetfs_bind(struct usb_gadget * gadget,struct usb_gadget_driver * driver)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
gadgetfs_disconnect(struct usb_gadget * gadget)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
gadgetfs_suspend(struct usb_gadget * gadget)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
is_valid_config(struct usb_config_descriptor * config,unsigned int total)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
dev_config(struct file * fd,const char __user * buf,size_t len,loff_t * ptr)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
dev_open(struct inode * inode,struct file * fd)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 *
gadgetfs_make_inode(struct super_block * sb,void * data,const struct file_operations * fops,int mode)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 *
gadgetfs_create_file(struct super_block * sb,char const * name,void * data,const struct file_operations * fops)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
gadgetfs_fill_super(struct super_block * sb,struct fs_context * fc)2011 gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc)
2012 {
2013 struct inode *inode;
2014 struct dev_data *dev;
2015 int rc;
2016
2017 mutex_lock(&sb_mutex);
2018
2019 if (the_device) {
2020 rc = -ESRCH;
2021 goto Done;
2022 }
2023
2024 CHIP = usb_get_gadget_udc_name();
2025 if (!CHIP) {
2026 rc = -ENODEV;
2027 goto Done;
2028 }
2029
2030 /* superblock */
2031 sb->s_blocksize = PAGE_SIZE;
2032 sb->s_blocksize_bits = PAGE_SHIFT;
2033 sb->s_magic = GADGETFS_MAGIC;
2034 sb->s_op = &gadget_fs_operations;
2035 sb->s_time_gran = 1;
2036
2037 /* root inode */
2038 inode = gadgetfs_make_inode (sb,
2039 NULL, &simple_dir_operations,
2040 S_IFDIR | S_IRUGO | S_IXUGO);
2041 if (!inode)
2042 goto Enomem;
2043 inode->i_op = &simple_dir_inode_operations;
2044 if (!(sb->s_root = d_make_root (inode)))
2045 goto Enomem;
2046
2047 /* the ep0 file is named after the controller we expect;
2048 * user mode code can use it for sanity checks, like we do.
2049 */
2050 dev = dev_new ();
2051 if (!dev)
2052 goto Enomem;
2053
2054 dev->sb = sb;
2055 dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2056 if (!dev->dentry) {
2057 put_dev(dev);
2058 goto Enomem;
2059 }
2060
2061 /* other endpoint files are available after hardware setup,
2062 * from binding to a controller.
2063 */
2064 the_device = dev;
2065 rc = 0;
2066 goto Done;
2067
2068 Enomem:
2069 kfree(CHIP);
2070 CHIP = NULL;
2071 rc = -ENOMEM;
2072
2073 Done:
2074 mutex_unlock(&sb_mutex);
2075 return rc;
2076 }
2077
2078 /* "mount -t gadgetfs path /dev/gadget" ends up here */
gadgetfs_get_tree(struct fs_context * fc)2079 static int gadgetfs_get_tree(struct fs_context *fc)
2080 {
2081 return get_tree_single(fc, gadgetfs_fill_super);
2082 }
2083
2084 static const struct fs_context_operations gadgetfs_context_ops = {
2085 .get_tree = gadgetfs_get_tree,
2086 };
2087
gadgetfs_init_fs_context(struct fs_context * fc)2088 static int gadgetfs_init_fs_context(struct fs_context *fc)
2089 {
2090 fc->ops = &gadgetfs_context_ops;
2091 return 0;
2092 }
2093
2094 static void
gadgetfs_kill_sb(struct super_block * sb)2095 gadgetfs_kill_sb (struct super_block *sb)
2096 {
2097 mutex_lock(&sb_mutex);
2098 kill_litter_super (sb);
2099 if (the_device) {
2100 put_dev (the_device);
2101 the_device = NULL;
2102 }
2103 kfree(CHIP);
2104 CHIP = NULL;
2105 mutex_unlock(&sb_mutex);
2106 }
2107
2108 /*----------------------------------------------------------------------*/
2109
2110 static struct file_system_type gadgetfs_type = {
2111 .owner = THIS_MODULE,
2112 .name = shortname,
2113 .init_fs_context = gadgetfs_init_fs_context,
2114 .kill_sb = gadgetfs_kill_sb,
2115 };
2116 MODULE_ALIAS_FS("gadgetfs");
2117
2118 /*----------------------------------------------------------------------*/
2119
init(void)2120 static int __init init (void)
2121 {
2122 int status;
2123
2124 status = register_filesystem (&gadgetfs_type);
2125 if (status == 0)
2126 pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2127 shortname, driver_desc);
2128 return status;
2129 }
2130 module_init (init);
2131
cleanup(void)2132 static void __exit cleanup (void)
2133 {
2134 pr_debug ("unregister %s\n", shortname);
2135 unregister_filesystem (&gadgetfs_type);
2136 }
2137 module_exit (cleanup);
2138
2139