1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * f_hid.c -- USB HID function driver
4  *
5  * Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/hid.h>
11 #include <linux/idr.h>
12 #include <linux/cdev.h>
13 #include <linux/mutex.h>
14 #include <linux/poll.h>
15 #include <linux/uaccess.h>
16 #include <linux/wait.h>
17 #include <linux/sched.h>
18 #include <linux/usb/g_hid.h>
19 
20 #include "u_f.h"
21 #include "u_hid.h"
22 
23 #define HIDG_MINORS	4
24 
25 static int major, minors;
26 static struct class *hidg_class;
27 static DEFINE_IDA(hidg_ida);
28 static DEFINE_MUTEX(hidg_ida_lock); /* protects access to hidg_ida */
29 
30 /*-------------------------------------------------------------------------*/
31 /*                            HID gadget struct                            */
32 
33 struct f_hidg_req_list {
34 	struct usb_request	*req;
35 	unsigned int		pos;
36 	struct list_head 	list;
37 };
38 
39 struct f_hidg {
40 	/* configuration */
41 	unsigned char			bInterfaceSubClass;
42 	unsigned char			bInterfaceProtocol;
43 	unsigned char			protocol;
44 	unsigned short			report_desc_length;
45 	char				*report_desc;
46 	unsigned short			report_length;
47 
48 	/* recv report */
49 	struct list_head		completed_out_req;
50 	spinlock_t			read_spinlock;
51 	wait_queue_head_t		read_queue;
52 	unsigned int			qlen;
53 
54 	/* send report */
55 	spinlock_t			write_spinlock;
56 	bool				write_pending;
57 	wait_queue_head_t		write_queue;
58 	struct usb_request		*req;
59 
60 	int				minor;
61 	struct cdev			cdev;
62 	struct usb_function		func;
63 
64 	struct usb_ep			*in_ep;
65 	struct usb_ep			*out_ep;
66 };
67 
68 static inline struct f_hidg *func_to_hidg(struct usb_function *f)
69 {
70 	return container_of(f, struct f_hidg, func);
71 }
72 
73 /*-------------------------------------------------------------------------*/
74 /*                           Static descriptors                            */
75 
76 static struct usb_interface_descriptor hidg_interface_desc = {
77 	.bLength		= sizeof hidg_interface_desc,
78 	.bDescriptorType	= USB_DT_INTERFACE,
79 	/* .bInterfaceNumber	= DYNAMIC */
80 	.bAlternateSetting	= 0,
81 	.bNumEndpoints		= 2,
82 	.bInterfaceClass	= USB_CLASS_HID,
83 	/* .bInterfaceSubClass	= DYNAMIC */
84 	/* .bInterfaceProtocol	= DYNAMIC */
85 	/* .iInterface		= DYNAMIC */
86 };
87 
88 static struct hid_descriptor hidg_desc = {
89 	.bLength			= sizeof hidg_desc,
90 	.bDescriptorType		= HID_DT_HID,
91 	.bcdHID				= 0x0101,
92 	.bCountryCode			= 0x00,
93 	.bNumDescriptors		= 0x1,
94 	/*.desc[0].bDescriptorType	= DYNAMIC */
95 	/*.desc[0].wDescriptorLenght	= DYNAMIC */
96 };
97 
98 /* Super-Speed Support */
99 
100 static struct usb_endpoint_descriptor hidg_ss_in_ep_desc = {
101 	.bLength		= USB_DT_ENDPOINT_SIZE,
102 	.bDescriptorType	= USB_DT_ENDPOINT,
103 	.bEndpointAddress	= USB_DIR_IN,
104 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
105 	/*.wMaxPacketSize	= DYNAMIC */
106 	.bInterval		= 4, /* FIXME: Add this field in the
107 				      * HID gadget configuration?
108 				      * (struct hidg_func_descriptor)
109 				      */
110 };
111 
112 static struct usb_ss_ep_comp_descriptor hidg_ss_in_comp_desc = {
113 	.bLength                = sizeof(hidg_ss_in_comp_desc),
114 	.bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
115 
116 	/* .bMaxBurst           = 0, */
117 	/* .bmAttributes        = 0, */
118 	/* .wBytesPerInterval   = DYNAMIC */
119 };
120 
121 static struct usb_endpoint_descriptor hidg_ss_out_ep_desc = {
122 	.bLength		= USB_DT_ENDPOINT_SIZE,
123 	.bDescriptorType	= USB_DT_ENDPOINT,
124 	.bEndpointAddress	= USB_DIR_OUT,
125 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
126 	/*.wMaxPacketSize	= DYNAMIC */
127 	.bInterval		= 4, /* FIXME: Add this field in the
128 				      * HID gadget configuration?
129 				      * (struct hidg_func_descriptor)
130 				      */
131 };
132 
133 static struct usb_ss_ep_comp_descriptor hidg_ss_out_comp_desc = {
134 	.bLength                = sizeof(hidg_ss_out_comp_desc),
135 	.bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
136 
137 	/* .bMaxBurst           = 0, */
138 	/* .bmAttributes        = 0, */
139 	/* .wBytesPerInterval   = DYNAMIC */
140 };
141 
142 static struct usb_descriptor_header *hidg_ss_descriptors[] = {
143 	(struct usb_descriptor_header *)&hidg_interface_desc,
144 	(struct usb_descriptor_header *)&hidg_desc,
145 	(struct usb_descriptor_header *)&hidg_ss_in_ep_desc,
146 	(struct usb_descriptor_header *)&hidg_ss_in_comp_desc,
147 	(struct usb_descriptor_header *)&hidg_ss_out_ep_desc,
148 	(struct usb_descriptor_header *)&hidg_ss_out_comp_desc,
149 	NULL,
150 };
151 
152 /* High-Speed Support */
153 
154 static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {
155 	.bLength		= USB_DT_ENDPOINT_SIZE,
156 	.bDescriptorType	= USB_DT_ENDPOINT,
157 	.bEndpointAddress	= USB_DIR_IN,
158 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
159 	/*.wMaxPacketSize	= DYNAMIC */
160 	.bInterval		= 4, /* FIXME: Add this field in the
161 				      * HID gadget configuration?
162 				      * (struct hidg_func_descriptor)
163 				      */
164 };
165 
166 static struct usb_endpoint_descriptor hidg_hs_out_ep_desc = {
167 	.bLength		= USB_DT_ENDPOINT_SIZE,
168 	.bDescriptorType	= USB_DT_ENDPOINT,
169 	.bEndpointAddress	= USB_DIR_OUT,
170 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
171 	/*.wMaxPacketSize	= DYNAMIC */
172 	.bInterval		= 4, /* FIXME: Add this field in the
173 				      * HID gadget configuration?
174 				      * (struct hidg_func_descriptor)
175 				      */
176 };
177 
178 static struct usb_descriptor_header *hidg_hs_descriptors[] = {
179 	(struct usb_descriptor_header *)&hidg_interface_desc,
180 	(struct usb_descriptor_header *)&hidg_desc,
181 	(struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
182 	(struct usb_descriptor_header *)&hidg_hs_out_ep_desc,
183 	NULL,
184 };
185 
186 /* Full-Speed Support */
187 
188 static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {
189 	.bLength		= USB_DT_ENDPOINT_SIZE,
190 	.bDescriptorType	= USB_DT_ENDPOINT,
191 	.bEndpointAddress	= USB_DIR_IN,
192 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
193 	/*.wMaxPacketSize	= DYNAMIC */
194 	.bInterval		= 10, /* FIXME: Add this field in the
195 				       * HID gadget configuration?
196 				       * (struct hidg_func_descriptor)
197 				       */
198 };
199 
200 static struct usb_endpoint_descriptor hidg_fs_out_ep_desc = {
201 	.bLength		= USB_DT_ENDPOINT_SIZE,
202 	.bDescriptorType	= USB_DT_ENDPOINT,
203 	.bEndpointAddress	= USB_DIR_OUT,
204 	.bmAttributes		= USB_ENDPOINT_XFER_INT,
205 	/*.wMaxPacketSize	= DYNAMIC */
206 	.bInterval		= 10, /* FIXME: Add this field in the
207 				       * HID gadget configuration?
208 				       * (struct hidg_func_descriptor)
209 				       */
210 };
211 
212 static struct usb_descriptor_header *hidg_fs_descriptors[] = {
213 	(struct usb_descriptor_header *)&hidg_interface_desc,
214 	(struct usb_descriptor_header *)&hidg_desc,
215 	(struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
216 	(struct usb_descriptor_header *)&hidg_fs_out_ep_desc,
217 	NULL,
218 };
219 
220 /*-------------------------------------------------------------------------*/
221 /*                                 Strings                                 */
222 
223 #define CT_FUNC_HID_IDX	0
224 
225 static struct usb_string ct_func_string_defs[] = {
226 	[CT_FUNC_HID_IDX].s	= "HID Interface",
227 	{},			/* end of list */
228 };
229 
230 static struct usb_gadget_strings ct_func_string_table = {
231 	.language	= 0x0409,	/* en-US */
232 	.strings	= ct_func_string_defs,
233 };
234 
235 static struct usb_gadget_strings *ct_func_strings[] = {
236 	&ct_func_string_table,
237 	NULL,
238 };
239 
240 /*-------------------------------------------------------------------------*/
241 /*                              Char Device                                */
242 
243 static ssize_t f_hidg_read(struct file *file, char __user *buffer,
244 			size_t count, loff_t *ptr)
245 {
246 	struct f_hidg *hidg = file->private_data;
247 	struct f_hidg_req_list *list;
248 	struct usb_request *req;
249 	unsigned long flags;
250 	int ret;
251 
252 	if (!count)
253 		return 0;
254 
255 	if (!access_ok(VERIFY_WRITE, buffer, count))
256 		return -EFAULT;
257 
258 	spin_lock_irqsave(&hidg->read_spinlock, flags);
259 
260 #define READ_COND (!list_empty(&hidg->completed_out_req))
261 
262 	/* wait for at least one buffer to complete */
263 	while (!READ_COND) {
264 		spin_unlock_irqrestore(&hidg->read_spinlock, flags);
265 		if (file->f_flags & O_NONBLOCK)
266 			return -EAGAIN;
267 
268 		if (wait_event_interruptible(hidg->read_queue, READ_COND))
269 			return -ERESTARTSYS;
270 
271 		spin_lock_irqsave(&hidg->read_spinlock, flags);
272 	}
273 
274 	/* pick the first one */
275 	list = list_first_entry(&hidg->completed_out_req,
276 				struct f_hidg_req_list, list);
277 
278 	/*
279 	 * Remove this from list to protect it from beign free()
280 	 * while host disables our function
281 	 */
282 	list_del(&list->list);
283 
284 	req = list->req;
285 	count = min_t(unsigned int, count, req->actual - list->pos);
286 	spin_unlock_irqrestore(&hidg->read_spinlock, flags);
287 
288 	/* copy to user outside spinlock */
289 	count -= copy_to_user(buffer, req->buf + list->pos, count);
290 	list->pos += count;
291 
292 	/*
293 	 * if this request is completely handled and transfered to
294 	 * userspace, remove its entry from the list and requeue it
295 	 * again. Otherwise, we will revisit it again upon the next
296 	 * call, taking into account its current read position.
297 	 */
298 	if (list->pos == req->actual) {
299 		kfree(list);
300 
301 		req->length = hidg->report_length;
302 		ret = usb_ep_queue(hidg->out_ep, req, GFP_KERNEL);
303 		if (ret < 0) {
304 			free_ep_req(hidg->out_ep, req);
305 			return ret;
306 		}
307 	} else {
308 		spin_lock_irqsave(&hidg->read_spinlock, flags);
309 		list_add(&list->list, &hidg->completed_out_req);
310 		spin_unlock_irqrestore(&hidg->read_spinlock, flags);
311 
312 		wake_up(&hidg->read_queue);
313 	}
314 
315 	return count;
316 }
317 
318 static void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req)
319 {
320 	struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;
321 	unsigned long flags;
322 
323 	if (req->status != 0) {
324 		ERROR(hidg->func.config->cdev,
325 			"End Point Request ERROR: %d\n", req->status);
326 	}
327 
328 	spin_lock_irqsave(&hidg->write_spinlock, flags);
329 	hidg->write_pending = 0;
330 	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
331 	wake_up(&hidg->write_queue);
332 }
333 
334 static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
335 			    size_t count, loff_t *offp)
336 {
337 	struct f_hidg *hidg  = file->private_data;
338 	struct usb_request *req;
339 	unsigned long flags;
340 	ssize_t status = -ENOMEM;
341 
342 	if (!access_ok(VERIFY_READ, buffer, count))
343 		return -EFAULT;
344 
345 	spin_lock_irqsave(&hidg->write_spinlock, flags);
346 
347 #define WRITE_COND (!hidg->write_pending)
348 try_again:
349 	/* write queue */
350 	while (!WRITE_COND) {
351 		spin_unlock_irqrestore(&hidg->write_spinlock, flags);
352 		if (file->f_flags & O_NONBLOCK)
353 			return -EAGAIN;
354 
355 		if (wait_event_interruptible_exclusive(
356 				hidg->write_queue, WRITE_COND))
357 			return -ERESTARTSYS;
358 
359 		spin_lock_irqsave(&hidg->write_spinlock, flags);
360 	}
361 
362 	hidg->write_pending = 1;
363 	req = hidg->req;
364 	count  = min_t(unsigned, count, hidg->report_length);
365 
366 	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
367 	status = copy_from_user(req->buf, buffer, count);
368 
369 	if (status != 0) {
370 		ERROR(hidg->func.config->cdev,
371 			"copy_from_user error\n");
372 		status = -EINVAL;
373 		goto release_write_pending;
374 	}
375 
376 	spin_lock_irqsave(&hidg->write_spinlock, flags);
377 
378 	/* when our function has been disabled by host */
379 	if (!hidg->req) {
380 		free_ep_req(hidg->in_ep, req);
381 		/*
382 		 * TODO
383 		 * Should we fail with error here?
384 		 */
385 		goto try_again;
386 	}
387 
388 	req->status   = 0;
389 	req->zero     = 0;
390 	req->length   = count;
391 	req->complete = f_hidg_req_complete;
392 	req->context  = hidg;
393 
394 	status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC);
395 	if (status < 0) {
396 		ERROR(hidg->func.config->cdev,
397 			"usb_ep_queue error on int endpoint %zd\n", status);
398 		goto release_write_pending_unlocked;
399 	} else {
400 		status = count;
401 	}
402 	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
403 
404 	return status;
405 release_write_pending:
406 	spin_lock_irqsave(&hidg->write_spinlock, flags);
407 release_write_pending_unlocked:
408 	hidg->write_pending = 0;
409 	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
410 
411 	wake_up(&hidg->write_queue);
412 
413 	return status;
414 }
415 
416 static __poll_t f_hidg_poll(struct file *file, poll_table *wait)
417 {
418 	struct f_hidg	*hidg  = file->private_data;
419 	__poll_t	ret = 0;
420 
421 	poll_wait(file, &hidg->read_queue, wait);
422 	poll_wait(file, &hidg->write_queue, wait);
423 
424 	if (WRITE_COND)
425 		ret |= EPOLLOUT | EPOLLWRNORM;
426 
427 	if (READ_COND)
428 		ret |= EPOLLIN | EPOLLRDNORM;
429 
430 	return ret;
431 }
432 
433 #undef WRITE_COND
434 #undef READ_COND
435 
436 static int f_hidg_release(struct inode *inode, struct file *fd)
437 {
438 	fd->private_data = NULL;
439 	return 0;
440 }
441 
442 static int f_hidg_open(struct inode *inode, struct file *fd)
443 {
444 	struct f_hidg *hidg =
445 		container_of(inode->i_cdev, struct f_hidg, cdev);
446 
447 	fd->private_data = hidg;
448 
449 	return 0;
450 }
451 
452 /*-------------------------------------------------------------------------*/
453 /*                                usb_function                             */
454 
455 static inline struct usb_request *hidg_alloc_ep_req(struct usb_ep *ep,
456 						    unsigned length)
457 {
458 	return alloc_ep_req(ep, length);
459 }
460 
461 static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req)
462 {
463 	struct f_hidg *hidg = (struct f_hidg *) req->context;
464 	struct usb_composite_dev *cdev = hidg->func.config->cdev;
465 	struct f_hidg_req_list *req_list;
466 	unsigned long flags;
467 
468 	switch (req->status) {
469 	case 0:
470 		req_list = kzalloc(sizeof(*req_list), GFP_ATOMIC);
471 		if (!req_list) {
472 			ERROR(cdev, "Unable to allocate mem for req_list\n");
473 			goto free_req;
474 		}
475 
476 		req_list->req = req;
477 
478 		spin_lock_irqsave(&hidg->read_spinlock, flags);
479 		list_add_tail(&req_list->list, &hidg->completed_out_req);
480 		spin_unlock_irqrestore(&hidg->read_spinlock, flags);
481 
482 		wake_up(&hidg->read_queue);
483 		break;
484 	default:
485 		ERROR(cdev, "Set report failed %d\n", req->status);
486 		/* FALLTHROUGH */
487 	case -ECONNABORTED:		/* hardware forced ep reset */
488 	case -ECONNRESET:		/* request dequeued */
489 	case -ESHUTDOWN:		/* disconnect from host */
490 free_req:
491 		free_ep_req(ep, req);
492 		return;
493 	}
494 }
495 
496 static int hidg_setup(struct usb_function *f,
497 		const struct usb_ctrlrequest *ctrl)
498 {
499 	struct f_hidg			*hidg = func_to_hidg(f);
500 	struct usb_composite_dev	*cdev = f->config->cdev;
501 	struct usb_request		*req  = cdev->req;
502 	int status = 0;
503 	__u16 value, length;
504 
505 	value	= __le16_to_cpu(ctrl->wValue);
506 	length	= __le16_to_cpu(ctrl->wLength);
507 
508 	VDBG(cdev,
509 	     "%s crtl_request : bRequestType:0x%x bRequest:0x%x Value:0x%x\n",
510 	     __func__, ctrl->bRequestType, ctrl->bRequest, value);
511 
512 	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
513 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
514 		  | HID_REQ_GET_REPORT):
515 		VDBG(cdev, "get_report\n");
516 
517 		/* send an empty report */
518 		length = min_t(unsigned, length, hidg->report_length);
519 		memset(req->buf, 0x0, length);
520 
521 		goto respond;
522 		break;
523 
524 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
525 		  | HID_REQ_GET_PROTOCOL):
526 		VDBG(cdev, "get_protocol\n");
527 		length = min_t(unsigned int, length, 1);
528 		((u8 *) req->buf)[0] = hidg->protocol;
529 		goto respond;
530 		break;
531 
532 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
533 		  | HID_REQ_SET_REPORT):
534 		VDBG(cdev, "set_report | wLength=%d\n", ctrl->wLength);
535 		goto stall;
536 		break;
537 
538 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
539 		  | HID_REQ_SET_PROTOCOL):
540 		VDBG(cdev, "set_protocol\n");
541 		if (value > HID_REPORT_PROTOCOL)
542 			goto stall;
543 		length = 0;
544 		/*
545 		 * We assume that programs implementing the Boot protocol
546 		 * are also compatible with the Report Protocol
547 		 */
548 		if (hidg->bInterfaceSubClass == USB_INTERFACE_SUBCLASS_BOOT) {
549 			hidg->protocol = value;
550 			goto respond;
551 		}
552 		goto stall;
553 		break;
554 
555 	case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8
556 		  | USB_REQ_GET_DESCRIPTOR):
557 		switch (value >> 8) {
558 		case HID_DT_HID:
559 		{
560 			struct hid_descriptor hidg_desc_copy = hidg_desc;
561 
562 			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: HID\n");
563 			hidg_desc_copy.desc[0].bDescriptorType = HID_DT_REPORT;
564 			hidg_desc_copy.desc[0].wDescriptorLength =
565 				cpu_to_le16(hidg->report_desc_length);
566 
567 			length = min_t(unsigned short, length,
568 						   hidg_desc_copy.bLength);
569 			memcpy(req->buf, &hidg_desc_copy, length);
570 			goto respond;
571 			break;
572 		}
573 		case HID_DT_REPORT:
574 			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");
575 			length = min_t(unsigned short, length,
576 						   hidg->report_desc_length);
577 			memcpy(req->buf, hidg->report_desc, length);
578 			goto respond;
579 			break;
580 
581 		default:
582 			VDBG(cdev, "Unknown descriptor request 0x%x\n",
583 				 value >> 8);
584 			goto stall;
585 			break;
586 		}
587 		break;
588 
589 	default:
590 		VDBG(cdev, "Unknown request 0x%x\n",
591 			 ctrl->bRequest);
592 		goto stall;
593 		break;
594 	}
595 
596 stall:
597 	return -EOPNOTSUPP;
598 
599 respond:
600 	req->zero = 0;
601 	req->length = length;
602 	status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
603 	if (status < 0)
604 		ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);
605 	return status;
606 }
607 
608 static void hidg_disable(struct usb_function *f)
609 {
610 	struct f_hidg *hidg = func_to_hidg(f);
611 	struct f_hidg_req_list *list, *next;
612 	unsigned long flags;
613 
614 	usb_ep_disable(hidg->in_ep);
615 	usb_ep_disable(hidg->out_ep);
616 
617 	spin_lock_irqsave(&hidg->read_spinlock, flags);
618 	list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {
619 		free_ep_req(hidg->out_ep, list->req);
620 		list_del(&list->list);
621 		kfree(list);
622 	}
623 	spin_unlock_irqrestore(&hidg->read_spinlock, flags);
624 
625 	spin_lock_irqsave(&hidg->write_spinlock, flags);
626 	if (!hidg->write_pending) {
627 		free_ep_req(hidg->in_ep, hidg->req);
628 		hidg->write_pending = 1;
629 	}
630 
631 	hidg->req = NULL;
632 	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
633 }
634 
635 static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
636 {
637 	struct usb_composite_dev		*cdev = f->config->cdev;
638 	struct f_hidg				*hidg = func_to_hidg(f);
639 	struct usb_request			*req_in = NULL;
640 	unsigned long				flags;
641 	int i, status = 0;
642 
643 	VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);
644 
645 	if (hidg->in_ep != NULL) {
646 		/* restart endpoint */
647 		usb_ep_disable(hidg->in_ep);
648 
649 		status = config_ep_by_speed(f->config->cdev->gadget, f,
650 					    hidg->in_ep);
651 		if (status) {
652 			ERROR(cdev, "config_ep_by_speed FAILED!\n");
653 			goto fail;
654 		}
655 		status = usb_ep_enable(hidg->in_ep);
656 		if (status < 0) {
657 			ERROR(cdev, "Enable IN endpoint FAILED!\n");
658 			goto fail;
659 		}
660 		hidg->in_ep->driver_data = hidg;
661 
662 		req_in = hidg_alloc_ep_req(hidg->in_ep, hidg->report_length);
663 		if (!req_in) {
664 			status = -ENOMEM;
665 			goto disable_ep_in;
666 		}
667 	}
668 
669 
670 	if (hidg->out_ep != NULL) {
671 		/* restart endpoint */
672 		usb_ep_disable(hidg->out_ep);
673 
674 		status = config_ep_by_speed(f->config->cdev->gadget, f,
675 					    hidg->out_ep);
676 		if (status) {
677 			ERROR(cdev, "config_ep_by_speed FAILED!\n");
678 			goto free_req_in;
679 		}
680 		status = usb_ep_enable(hidg->out_ep);
681 		if (status < 0) {
682 			ERROR(cdev, "Enable OUT endpoint FAILED!\n");
683 			goto free_req_in;
684 		}
685 		hidg->out_ep->driver_data = hidg;
686 
687 		/*
688 		 * allocate a bunch of read buffers and queue them all at once.
689 		 */
690 		for (i = 0; i < hidg->qlen && status == 0; i++) {
691 			struct usb_request *req =
692 					hidg_alloc_ep_req(hidg->out_ep,
693 							  hidg->report_length);
694 			if (req) {
695 				req->complete = hidg_set_report_complete;
696 				req->context  = hidg;
697 				status = usb_ep_queue(hidg->out_ep, req,
698 						      GFP_ATOMIC);
699 				if (status) {
700 					ERROR(cdev, "%s queue req --> %d\n",
701 						hidg->out_ep->name, status);
702 					free_ep_req(hidg->out_ep, req);
703 				}
704 			} else {
705 				status = -ENOMEM;
706 				goto disable_out_ep;
707 			}
708 		}
709 	}
710 
711 	if (hidg->in_ep != NULL) {
712 		spin_lock_irqsave(&hidg->write_spinlock, flags);
713 		hidg->req = req_in;
714 		hidg->write_pending = 0;
715 		spin_unlock_irqrestore(&hidg->write_spinlock, flags);
716 
717 		wake_up(&hidg->write_queue);
718 	}
719 	return 0;
720 disable_out_ep:
721 	usb_ep_disable(hidg->out_ep);
722 free_req_in:
723 	if (req_in)
724 		free_ep_req(hidg->in_ep, req_in);
725 
726 disable_ep_in:
727 	if (hidg->in_ep)
728 		usb_ep_disable(hidg->in_ep);
729 
730 fail:
731 	return status;
732 }
733 
734 static const struct file_operations f_hidg_fops = {
735 	.owner		= THIS_MODULE,
736 	.open		= f_hidg_open,
737 	.release	= f_hidg_release,
738 	.write		= f_hidg_write,
739 	.read		= f_hidg_read,
740 	.poll		= f_hidg_poll,
741 	.llseek		= noop_llseek,
742 };
743 
744 static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
745 {
746 	struct usb_ep		*ep;
747 	struct f_hidg		*hidg = func_to_hidg(f);
748 	struct usb_string	*us;
749 	struct device		*device;
750 	int			status;
751 	dev_t			dev;
752 
753 	/* maybe allocate device-global string IDs, and patch descriptors */
754 	us = usb_gstrings_attach(c->cdev, ct_func_strings,
755 				 ARRAY_SIZE(ct_func_string_defs));
756 	if (IS_ERR(us))
757 		return PTR_ERR(us);
758 	hidg_interface_desc.iInterface = us[CT_FUNC_HID_IDX].id;
759 
760 	/* allocate instance-specific interface IDs, and patch descriptors */
761 	status = usb_interface_id(c, f);
762 	if (status < 0)
763 		goto fail;
764 	hidg_interface_desc.bInterfaceNumber = status;
765 
766 	/* allocate instance-specific endpoints */
767 	status = -ENODEV;
768 	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
769 	if (!ep)
770 		goto fail;
771 	hidg->in_ep = ep;
772 
773 	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc);
774 	if (!ep)
775 		goto fail;
776 	hidg->out_ep = ep;
777 
778 	/* set descriptor dynamic values */
779 	hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
780 	hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
781 	hidg->protocol = HID_REPORT_PROTOCOL;
782 	hidg_ss_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
783 	hidg_ss_in_comp_desc.wBytesPerInterval =
784 				cpu_to_le16(hidg->report_length);
785 	hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
786 	hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
787 	hidg_ss_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
788 	hidg_ss_out_comp_desc.wBytesPerInterval =
789 				cpu_to_le16(hidg->report_length);
790 	hidg_hs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
791 	hidg_fs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
792 	/*
793 	 * We can use hidg_desc struct here but we should not relay
794 	 * that its content won't change after returning from this function.
795 	 */
796 	hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
797 	hidg_desc.desc[0].wDescriptorLength =
798 		cpu_to_le16(hidg->report_desc_length);
799 
800 	hidg_hs_in_ep_desc.bEndpointAddress =
801 		hidg_fs_in_ep_desc.bEndpointAddress;
802 	hidg_hs_out_ep_desc.bEndpointAddress =
803 		hidg_fs_out_ep_desc.bEndpointAddress;
804 
805 	hidg_ss_in_ep_desc.bEndpointAddress =
806 		hidg_fs_in_ep_desc.bEndpointAddress;
807 	hidg_ss_out_ep_desc.bEndpointAddress =
808 		hidg_fs_out_ep_desc.bEndpointAddress;
809 
810 	status = usb_assign_descriptors(f, hidg_fs_descriptors,
811 			hidg_hs_descriptors, hidg_ss_descriptors, NULL);
812 	if (status)
813 		goto fail;
814 
815 	spin_lock_init(&hidg->write_spinlock);
816 	hidg->write_pending = 1;
817 	hidg->req = NULL;
818 	spin_lock_init(&hidg->read_spinlock);
819 	init_waitqueue_head(&hidg->write_queue);
820 	init_waitqueue_head(&hidg->read_queue);
821 	INIT_LIST_HEAD(&hidg->completed_out_req);
822 
823 	/* create char device */
824 	cdev_init(&hidg->cdev, &f_hidg_fops);
825 	dev = MKDEV(major, hidg->minor);
826 	status = cdev_add(&hidg->cdev, dev, 1);
827 	if (status)
828 		goto fail_free_descs;
829 
830 	device = device_create(hidg_class, NULL, dev, NULL,
831 			       "%s%d", "hidg", hidg->minor);
832 	if (IS_ERR(device)) {
833 		status = PTR_ERR(device);
834 		goto del;
835 	}
836 
837 	return 0;
838 del:
839 	cdev_del(&hidg->cdev);
840 fail_free_descs:
841 	usb_free_all_descriptors(f);
842 fail:
843 	ERROR(f->config->cdev, "hidg_bind FAILED\n");
844 	if (hidg->req != NULL)
845 		free_ep_req(hidg->in_ep, hidg->req);
846 
847 	return status;
848 }
849 
850 static inline int hidg_get_minor(void)
851 {
852 	int ret;
853 
854 	ret = ida_simple_get(&hidg_ida, 0, 0, GFP_KERNEL);
855 	if (ret >= HIDG_MINORS) {
856 		ida_simple_remove(&hidg_ida, ret);
857 		ret = -ENODEV;
858 	}
859 
860 	return ret;
861 }
862 
863 static inline struct f_hid_opts *to_f_hid_opts(struct config_item *item)
864 {
865 	return container_of(to_config_group(item), struct f_hid_opts,
866 			    func_inst.group);
867 }
868 
869 static void hid_attr_release(struct config_item *item)
870 {
871 	struct f_hid_opts *opts = to_f_hid_opts(item);
872 
873 	usb_put_function_instance(&opts->func_inst);
874 }
875 
876 static struct configfs_item_operations hidg_item_ops = {
877 	.release	= hid_attr_release,
878 };
879 
880 #define F_HID_OPT(name, prec, limit)					\
881 static ssize_t f_hid_opts_##name##_show(struct config_item *item, char *page)\
882 {									\
883 	struct f_hid_opts *opts = to_f_hid_opts(item);			\
884 	int result;							\
885 									\
886 	mutex_lock(&opts->lock);					\
887 	result = sprintf(page, "%d\n", opts->name);			\
888 	mutex_unlock(&opts->lock);					\
889 									\
890 	return result;							\
891 }									\
892 									\
893 static ssize_t f_hid_opts_##name##_store(struct config_item *item,	\
894 					 const char *page, size_t len)	\
895 {									\
896 	struct f_hid_opts *opts = to_f_hid_opts(item);			\
897 	int ret;							\
898 	u##prec num;							\
899 									\
900 	mutex_lock(&opts->lock);					\
901 	if (opts->refcnt) {						\
902 		ret = -EBUSY;						\
903 		goto end;						\
904 	}								\
905 									\
906 	ret = kstrtou##prec(page, 0, &num);				\
907 	if (ret)							\
908 		goto end;						\
909 									\
910 	if (num > limit) {						\
911 		ret = -EINVAL;						\
912 		goto end;						\
913 	}								\
914 	opts->name = num;						\
915 	ret = len;							\
916 									\
917 end:									\
918 	mutex_unlock(&opts->lock);					\
919 	return ret;							\
920 }									\
921 									\
922 CONFIGFS_ATTR(f_hid_opts_, name)
923 
924 F_HID_OPT(subclass, 8, 255);
925 F_HID_OPT(protocol, 8, 255);
926 F_HID_OPT(report_length, 16, 65535);
927 
928 static ssize_t f_hid_opts_report_desc_show(struct config_item *item, char *page)
929 {
930 	struct f_hid_opts *opts = to_f_hid_opts(item);
931 	int result;
932 
933 	mutex_lock(&opts->lock);
934 	result = opts->report_desc_length;
935 	memcpy(page, opts->report_desc, opts->report_desc_length);
936 	mutex_unlock(&opts->lock);
937 
938 	return result;
939 }
940 
941 static ssize_t f_hid_opts_report_desc_store(struct config_item *item,
942 					    const char *page, size_t len)
943 {
944 	struct f_hid_opts *opts = to_f_hid_opts(item);
945 	int ret = -EBUSY;
946 	char *d;
947 
948 	mutex_lock(&opts->lock);
949 
950 	if (opts->refcnt)
951 		goto end;
952 	if (len > PAGE_SIZE) {
953 		ret = -ENOSPC;
954 		goto end;
955 	}
956 	d = kmemdup(page, len, GFP_KERNEL);
957 	if (!d) {
958 		ret = -ENOMEM;
959 		goto end;
960 	}
961 	kfree(opts->report_desc);
962 	opts->report_desc = d;
963 	opts->report_desc_length = len;
964 	opts->report_desc_alloc = true;
965 	ret = len;
966 end:
967 	mutex_unlock(&opts->lock);
968 	return ret;
969 }
970 
971 CONFIGFS_ATTR(f_hid_opts_, report_desc);
972 
973 static ssize_t f_hid_opts_dev_show(struct config_item *item, char *page)
974 {
975 	struct f_hid_opts *opts = to_f_hid_opts(item);
976 
977 	return sprintf(page, "%d:%d\n", major, opts->minor);
978 }
979 
980 CONFIGFS_ATTR_RO(f_hid_opts_, dev);
981 
982 static struct configfs_attribute *hid_attrs[] = {
983 	&f_hid_opts_attr_subclass,
984 	&f_hid_opts_attr_protocol,
985 	&f_hid_opts_attr_report_length,
986 	&f_hid_opts_attr_report_desc,
987 	&f_hid_opts_attr_dev,
988 	NULL,
989 };
990 
991 static const struct config_item_type hid_func_type = {
992 	.ct_item_ops	= &hidg_item_ops,
993 	.ct_attrs	= hid_attrs,
994 	.ct_owner	= THIS_MODULE,
995 };
996 
997 static inline void hidg_put_minor(int minor)
998 {
999 	ida_simple_remove(&hidg_ida, minor);
1000 }
1001 
1002 static void hidg_free_inst(struct usb_function_instance *f)
1003 {
1004 	struct f_hid_opts *opts;
1005 
1006 	opts = container_of(f, struct f_hid_opts, func_inst);
1007 
1008 	mutex_lock(&hidg_ida_lock);
1009 
1010 	hidg_put_minor(opts->minor);
1011 	if (ida_is_empty(&hidg_ida))
1012 		ghid_cleanup();
1013 
1014 	mutex_unlock(&hidg_ida_lock);
1015 
1016 	if (opts->report_desc_alloc)
1017 		kfree(opts->report_desc);
1018 
1019 	kfree(opts);
1020 }
1021 
1022 static struct usb_function_instance *hidg_alloc_inst(void)
1023 {
1024 	struct f_hid_opts *opts;
1025 	struct usb_function_instance *ret;
1026 	int status = 0;
1027 
1028 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1029 	if (!opts)
1030 		return ERR_PTR(-ENOMEM);
1031 	mutex_init(&opts->lock);
1032 	opts->func_inst.free_func_inst = hidg_free_inst;
1033 	ret = &opts->func_inst;
1034 
1035 	mutex_lock(&hidg_ida_lock);
1036 
1037 	if (ida_is_empty(&hidg_ida)) {
1038 		status = ghid_setup(NULL, HIDG_MINORS);
1039 		if (status)  {
1040 			ret = ERR_PTR(status);
1041 			kfree(opts);
1042 			goto unlock;
1043 		}
1044 	}
1045 
1046 	opts->minor = hidg_get_minor();
1047 	if (opts->minor < 0) {
1048 		ret = ERR_PTR(opts->minor);
1049 		kfree(opts);
1050 		if (ida_is_empty(&hidg_ida))
1051 			ghid_cleanup();
1052 		goto unlock;
1053 	}
1054 	config_group_init_type_name(&opts->func_inst.group, "", &hid_func_type);
1055 
1056 unlock:
1057 	mutex_unlock(&hidg_ida_lock);
1058 	return ret;
1059 }
1060 
1061 static void hidg_free(struct usb_function *f)
1062 {
1063 	struct f_hidg *hidg;
1064 	struct f_hid_opts *opts;
1065 
1066 	hidg = func_to_hidg(f);
1067 	opts = container_of(f->fi, struct f_hid_opts, func_inst);
1068 	kfree(hidg->report_desc);
1069 	kfree(hidg);
1070 	mutex_lock(&opts->lock);
1071 	--opts->refcnt;
1072 	mutex_unlock(&opts->lock);
1073 }
1074 
1075 static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
1076 {
1077 	struct f_hidg *hidg = func_to_hidg(f);
1078 
1079 	device_destroy(hidg_class, MKDEV(major, hidg->minor));
1080 	cdev_del(&hidg->cdev);
1081 
1082 	usb_free_all_descriptors(f);
1083 }
1084 
1085 static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
1086 {
1087 	struct f_hidg *hidg;
1088 	struct f_hid_opts *opts;
1089 
1090 	/* allocate and initialize one new instance */
1091 	hidg = kzalloc(sizeof(*hidg), GFP_KERNEL);
1092 	if (!hidg)
1093 		return ERR_PTR(-ENOMEM);
1094 
1095 	opts = container_of(fi, struct f_hid_opts, func_inst);
1096 
1097 	mutex_lock(&opts->lock);
1098 	++opts->refcnt;
1099 
1100 	hidg->minor = opts->minor;
1101 	hidg->bInterfaceSubClass = opts->subclass;
1102 	hidg->bInterfaceProtocol = opts->protocol;
1103 	hidg->report_length = opts->report_length;
1104 	hidg->report_desc_length = opts->report_desc_length;
1105 	if (opts->report_desc) {
1106 		hidg->report_desc = kmemdup(opts->report_desc,
1107 					    opts->report_desc_length,
1108 					    GFP_KERNEL);
1109 		if (!hidg->report_desc) {
1110 			kfree(hidg);
1111 			mutex_unlock(&opts->lock);
1112 			return ERR_PTR(-ENOMEM);
1113 		}
1114 	}
1115 
1116 	mutex_unlock(&opts->lock);
1117 
1118 	hidg->func.name    = "hid";
1119 	hidg->func.bind    = hidg_bind;
1120 	hidg->func.unbind  = hidg_unbind;
1121 	hidg->func.set_alt = hidg_set_alt;
1122 	hidg->func.disable = hidg_disable;
1123 	hidg->func.setup   = hidg_setup;
1124 	hidg->func.free_func = hidg_free;
1125 
1126 	/* this could me made configurable at some point */
1127 	hidg->qlen	   = 4;
1128 
1129 	return &hidg->func;
1130 }
1131 
1132 DECLARE_USB_FUNCTION_INIT(hid, hidg_alloc_inst, hidg_alloc);
1133 MODULE_LICENSE("GPL");
1134 MODULE_AUTHOR("Fabien Chouteau");
1135 
1136 int ghid_setup(struct usb_gadget *g, int count)
1137 {
1138 	int status;
1139 	dev_t dev;
1140 
1141 	hidg_class = class_create(THIS_MODULE, "hidg");
1142 	if (IS_ERR(hidg_class)) {
1143 		status = PTR_ERR(hidg_class);
1144 		hidg_class = NULL;
1145 		return status;
1146 	}
1147 
1148 	status = alloc_chrdev_region(&dev, 0, count, "hidg");
1149 	if (status) {
1150 		class_destroy(hidg_class);
1151 		hidg_class = NULL;
1152 		return status;
1153 	}
1154 
1155 	major = MAJOR(dev);
1156 	minors = count;
1157 
1158 	return 0;
1159 }
1160 
1161 void ghid_cleanup(void)
1162 {
1163 	if (major) {
1164 		unregister_chrdev_region(MKDEV(major, 0), minors);
1165 		major = minors = 0;
1166 	}
1167 
1168 	class_destroy(hidg_class);
1169 	hidg_class = NULL;
1170 }
1171