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