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 			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: HID\n");
441 			length = min_t(unsigned short, length,
442 						   hidg_desc.bLength);
443 			memcpy(req->buf, &hidg_desc, length);
444 			goto respond;
445 			break;
446 		case HID_DT_REPORT:
447 			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");
448 			length = min_t(unsigned short, length,
449 						   hidg->report_desc_length);
450 			memcpy(req->buf, hidg->report_desc, length);
451 			goto respond;
452 			break;
453 
454 		default:
455 			VDBG(cdev, "Unknown descriptor request 0x%x\n",
456 				 value >> 8);
457 			goto stall;
458 			break;
459 		}
460 		break;
461 
462 	default:
463 		VDBG(cdev, "Unknown request 0x%x\n",
464 			 ctrl->bRequest);
465 		goto stall;
466 		break;
467 	}
468 
469 stall:
470 	return -EOPNOTSUPP;
471 
472 respond:
473 	req->zero = 0;
474 	req->length = length;
475 	status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
476 	if (status < 0)
477 		ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);
478 	return status;
479 }
480 
481 static void hidg_disable(struct usb_function *f)
482 {
483 	struct f_hidg *hidg = func_to_hidg(f);
484 	struct f_hidg_req_list *list, *next;
485 
486 	usb_ep_disable(hidg->in_ep);
487 	hidg->in_ep->driver_data = NULL;
488 
489 	usb_ep_disable(hidg->out_ep);
490 	hidg->out_ep->driver_data = NULL;
491 
492 	list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {
493 		list_del(&list->list);
494 		kfree(list);
495 	}
496 }
497 
498 static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
499 {
500 	struct usb_composite_dev		*cdev = f->config->cdev;
501 	struct f_hidg				*hidg = func_to_hidg(f);
502 	int i, status = 0;
503 
504 	VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);
505 
506 	if (hidg->in_ep != NULL) {
507 		/* restart endpoint */
508 		if (hidg->in_ep->driver_data != NULL)
509 			usb_ep_disable(hidg->in_ep);
510 
511 		status = config_ep_by_speed(f->config->cdev->gadget, f,
512 					    hidg->in_ep);
513 		if (status) {
514 			ERROR(cdev, "config_ep_by_speed FAILED!\n");
515 			goto fail;
516 		}
517 		status = usb_ep_enable(hidg->in_ep);
518 		if (status < 0) {
519 			ERROR(cdev, "Enable IN endpoint FAILED!\n");
520 			goto fail;
521 		}
522 		hidg->in_ep->driver_data = hidg;
523 	}
524 
525 
526 	if (hidg->out_ep != NULL) {
527 		/* restart endpoint */
528 		if (hidg->out_ep->driver_data != NULL)
529 			usb_ep_disable(hidg->out_ep);
530 
531 		status = config_ep_by_speed(f->config->cdev->gadget, f,
532 					    hidg->out_ep);
533 		if (status) {
534 			ERROR(cdev, "config_ep_by_speed FAILED!\n");
535 			goto fail;
536 		}
537 		status = usb_ep_enable(hidg->out_ep);
538 		if (status < 0) {
539 			ERROR(cdev, "Enable IN endpoint FAILED!\n");
540 			goto fail;
541 		}
542 		hidg->out_ep->driver_data = hidg;
543 
544 		/*
545 		 * allocate a bunch of read buffers and queue them all at once.
546 		 */
547 		for (i = 0; i < hidg->qlen && status == 0; i++) {
548 			struct usb_request *req =
549 					hidg_alloc_ep_req(hidg->out_ep,
550 							  hidg->report_length);
551 			if (req) {
552 				req->complete = hidg_set_report_complete;
553 				req->context  = hidg;
554 				status = usb_ep_queue(hidg->out_ep, req,
555 						      GFP_ATOMIC);
556 				if (status)
557 					ERROR(cdev, "%s queue req --> %d\n",
558 						hidg->out_ep->name, status);
559 			} else {
560 				usb_ep_disable(hidg->out_ep);
561 				hidg->out_ep->driver_data = NULL;
562 				status = -ENOMEM;
563 				goto fail;
564 			}
565 		}
566 	}
567 
568 fail:
569 	return status;
570 }
571 
572 const struct file_operations f_hidg_fops = {
573 	.owner		= THIS_MODULE,
574 	.open		= f_hidg_open,
575 	.release	= f_hidg_release,
576 	.write		= f_hidg_write,
577 	.read		= f_hidg_read,
578 	.poll		= f_hidg_poll,
579 	.llseek		= noop_llseek,
580 };
581 
582 static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
583 {
584 	struct usb_ep		*ep;
585 	struct f_hidg		*hidg = func_to_hidg(f);
586 	struct usb_string	*us;
587 	struct device		*device;
588 	int			status;
589 	dev_t			dev;
590 
591 	/* maybe allocate device-global string IDs, and patch descriptors */
592 	us = usb_gstrings_attach(c->cdev, ct_func_strings,
593 				 ARRAY_SIZE(ct_func_string_defs));
594 	if (IS_ERR(us))
595 		return PTR_ERR(us);
596 	hidg_interface_desc.iInterface = us[CT_FUNC_HID_IDX].id;
597 
598 	/* allocate instance-specific interface IDs, and patch descriptors */
599 	status = usb_interface_id(c, f);
600 	if (status < 0)
601 		goto fail;
602 	hidg_interface_desc.bInterfaceNumber = status;
603 
604 	/* allocate instance-specific endpoints */
605 	status = -ENODEV;
606 	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
607 	if (!ep)
608 		goto fail;
609 	ep->driver_data = c->cdev;	/* claim */
610 	hidg->in_ep = ep;
611 
612 	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc);
613 	if (!ep)
614 		goto fail;
615 	ep->driver_data = c->cdev;	/* claim */
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 	hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
636 	hidg_desc.desc[0].wDescriptorLength =
637 		cpu_to_le16(hidg->report_desc_length);
638 
639 	hidg_hs_in_ep_desc.bEndpointAddress =
640 		hidg_fs_in_ep_desc.bEndpointAddress;
641 	hidg_hs_out_ep_desc.bEndpointAddress =
642 		hidg_fs_out_ep_desc.bEndpointAddress;
643 
644 	status = usb_assign_descriptors(f, hidg_fs_descriptors,
645 			hidg_hs_descriptors, NULL);
646 	if (status)
647 		goto fail;
648 
649 	mutex_init(&hidg->lock);
650 	spin_lock_init(&hidg->spinlock);
651 	init_waitqueue_head(&hidg->write_queue);
652 	init_waitqueue_head(&hidg->read_queue);
653 	INIT_LIST_HEAD(&hidg->completed_out_req);
654 
655 	/* create char device */
656 	cdev_init(&hidg->cdev, &f_hidg_fops);
657 	dev = MKDEV(major, hidg->minor);
658 	status = cdev_add(&hidg->cdev, dev, 1);
659 	if (status)
660 		goto fail_free_descs;
661 
662 	device = device_create(hidg_class, NULL, dev, NULL,
663 			       "%s%d", "hidg", hidg->minor);
664 	if (IS_ERR(device)) {
665 		status = PTR_ERR(device);
666 		goto del;
667 	}
668 
669 	return 0;
670 del:
671 	cdev_del(&hidg->cdev);
672 fail_free_descs:
673 	usb_free_all_descriptors(f);
674 fail:
675 	ERROR(f->config->cdev, "hidg_bind FAILED\n");
676 	if (hidg->req != NULL) {
677 		kfree(hidg->req->buf);
678 		if (hidg->in_ep != NULL)
679 			usb_ep_free_request(hidg->in_ep, hidg->req);
680 	}
681 
682 	return status;
683 }
684 
685 static inline int hidg_get_minor(void)
686 {
687 	int ret;
688 
689 	ret = ida_simple_get(&hidg_ida, 0, 0, GFP_KERNEL);
690 
691 	return ret;
692 }
693 
694 static inline struct f_hid_opts *to_f_hid_opts(struct config_item *item)
695 {
696 	return container_of(to_config_group(item), struct f_hid_opts,
697 			    func_inst.group);
698 }
699 
700 CONFIGFS_ATTR_STRUCT(f_hid_opts);
701 CONFIGFS_ATTR_OPS(f_hid_opts);
702 
703 static void hid_attr_release(struct config_item *item)
704 {
705 	struct f_hid_opts *opts = to_f_hid_opts(item);
706 
707 	usb_put_function_instance(&opts->func_inst);
708 }
709 
710 static struct configfs_item_operations hidg_item_ops = {
711 	.release	= hid_attr_release,
712 	.show_attribute	= f_hid_opts_attr_show,
713 	.store_attribute = f_hid_opts_attr_store,
714 };
715 
716 #define F_HID_OPT(name, prec, limit)					\
717 static ssize_t f_hid_opts_##name##_show(struct f_hid_opts *opts, char *page)\
718 {									\
719 	int result;							\
720 									\
721 	mutex_lock(&opts->lock);					\
722 	result = sprintf(page, "%d\n", opts->name);			\
723 	mutex_unlock(&opts->lock);					\
724 									\
725 	return result;							\
726 }									\
727 									\
728 static ssize_t f_hid_opts_##name##_store(struct f_hid_opts *opts,	\
729 					 const char *page, size_t len)	\
730 {									\
731 	int ret;							\
732 	u##prec num;							\
733 									\
734 	mutex_lock(&opts->lock);					\
735 	if (opts->refcnt) {						\
736 		ret = -EBUSY;						\
737 		goto end;						\
738 	}								\
739 									\
740 	ret = kstrtou##prec(page, 0, &num);				\
741 	if (ret)							\
742 		goto end;						\
743 									\
744 	if (num > limit) {						\
745 		ret = -EINVAL;						\
746 		goto end;						\
747 	}								\
748 	opts->name = num;						\
749 	ret = len;							\
750 									\
751 end:									\
752 	mutex_unlock(&opts->lock);					\
753 	return ret;							\
754 }									\
755 									\
756 static struct f_hid_opts_attribute f_hid_opts_##name =			\
757 	__CONFIGFS_ATTR(name, S_IRUGO | S_IWUSR, f_hid_opts_##name##_show,\
758 			f_hid_opts_##name##_store)
759 
760 F_HID_OPT(subclass, 8, 255);
761 F_HID_OPT(protocol, 8, 255);
762 F_HID_OPT(report_length, 16, 65535);
763 
764 static ssize_t f_hid_opts_report_desc_show(struct f_hid_opts *opts, char *page)
765 {
766 	int result;
767 
768 	mutex_lock(&opts->lock);
769 	result = opts->report_desc_length;
770 	memcpy(page, opts->report_desc, opts->report_desc_length);
771 	mutex_unlock(&opts->lock);
772 
773 	return result;
774 }
775 
776 static ssize_t f_hid_opts_report_desc_store(struct f_hid_opts *opts,
777 					    const char *page, size_t len)
778 {
779 	int ret = -EBUSY;
780 	char *d;
781 
782 	mutex_lock(&opts->lock);
783 
784 	if (opts->refcnt)
785 		goto end;
786 	if (len > PAGE_SIZE) {
787 		ret = -ENOSPC;
788 		goto end;
789 	}
790 	d = kmemdup(page, len, GFP_KERNEL);
791 	if (!d) {
792 		ret = -ENOMEM;
793 		goto end;
794 	}
795 	kfree(opts->report_desc);
796 	opts->report_desc = d;
797 	opts->report_desc_length = len;
798 	opts->report_desc_alloc = true;
799 	ret = len;
800 end:
801 	mutex_unlock(&opts->lock);
802 	return ret;
803 }
804 
805 static struct f_hid_opts_attribute f_hid_opts_report_desc =
806 	__CONFIGFS_ATTR(report_desc, S_IRUGO | S_IWUSR,
807 			f_hid_opts_report_desc_show,
808 			f_hid_opts_report_desc_store);
809 
810 static struct configfs_attribute *hid_attrs[] = {
811 	&f_hid_opts_subclass.attr,
812 	&f_hid_opts_protocol.attr,
813 	&f_hid_opts_report_length.attr,
814 	&f_hid_opts_report_desc.attr,
815 	NULL,
816 };
817 
818 static struct config_item_type hid_func_type = {
819 	.ct_item_ops	= &hidg_item_ops,
820 	.ct_attrs	= hid_attrs,
821 	.ct_owner	= THIS_MODULE,
822 };
823 
824 static inline void hidg_put_minor(int minor)
825 {
826 	ida_simple_remove(&hidg_ida, minor);
827 }
828 
829 static void hidg_free_inst(struct usb_function_instance *f)
830 {
831 	struct f_hid_opts *opts;
832 
833 	opts = container_of(f, struct f_hid_opts, func_inst);
834 
835 	mutex_lock(&hidg_ida_lock);
836 
837 	hidg_put_minor(opts->minor);
838 	if (idr_is_empty(&hidg_ida.idr))
839 		ghid_cleanup();
840 
841 	mutex_unlock(&hidg_ida_lock);
842 
843 	if (opts->report_desc_alloc)
844 		kfree(opts->report_desc);
845 
846 	kfree(opts);
847 }
848 
849 static struct usb_function_instance *hidg_alloc_inst(void)
850 {
851 	struct f_hid_opts *opts;
852 	struct usb_function_instance *ret;
853 	int status = 0;
854 
855 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
856 	if (!opts)
857 		return ERR_PTR(-ENOMEM);
858 	mutex_init(&opts->lock);
859 	opts->func_inst.free_func_inst = hidg_free_inst;
860 	ret = &opts->func_inst;
861 
862 	mutex_lock(&hidg_ida_lock);
863 
864 	if (idr_is_empty(&hidg_ida.idr)) {
865 		status = ghid_setup(NULL, HIDG_MINORS);
866 		if (status)  {
867 			ret = ERR_PTR(status);
868 			kfree(opts);
869 			goto unlock;
870 		}
871 	}
872 
873 	opts->minor = hidg_get_minor();
874 	if (opts->minor < 0) {
875 		ret = ERR_PTR(opts->minor);
876 		kfree(opts);
877 		if (idr_is_empty(&hidg_ida.idr))
878 			ghid_cleanup();
879 		goto unlock;
880 	}
881 	config_group_init_type_name(&opts->func_inst.group, "", &hid_func_type);
882 
883 unlock:
884 	mutex_unlock(&hidg_ida_lock);
885 	return ret;
886 }
887 
888 static void hidg_free(struct usb_function *f)
889 {
890 	struct f_hidg *hidg;
891 	struct f_hid_opts *opts;
892 
893 	hidg = func_to_hidg(f);
894 	opts = container_of(f->fi, struct f_hid_opts, func_inst);
895 	kfree(hidg->report_desc);
896 	kfree(hidg);
897 	mutex_lock(&opts->lock);
898 	--opts->refcnt;
899 	mutex_unlock(&opts->lock);
900 }
901 
902 static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
903 {
904 	struct f_hidg *hidg = func_to_hidg(f);
905 
906 	device_destroy(hidg_class, MKDEV(major, hidg->minor));
907 	cdev_del(&hidg->cdev);
908 
909 	/* disable/free request and end point */
910 	usb_ep_disable(hidg->in_ep);
911 	usb_ep_dequeue(hidg->in_ep, hidg->req);
912 	kfree(hidg->req->buf);
913 	usb_ep_free_request(hidg->in_ep, hidg->req);
914 
915 	usb_free_all_descriptors(f);
916 }
917 
918 static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
919 {
920 	struct f_hidg *hidg;
921 	struct f_hid_opts *opts;
922 
923 	/* allocate and initialize one new instance */
924 	hidg = kzalloc(sizeof(*hidg), GFP_KERNEL);
925 	if (!hidg)
926 		return ERR_PTR(-ENOMEM);
927 
928 	opts = container_of(fi, struct f_hid_opts, func_inst);
929 
930 	mutex_lock(&opts->lock);
931 	++opts->refcnt;
932 
933 	hidg->minor = opts->minor;
934 	hidg->bInterfaceSubClass = opts->subclass;
935 	hidg->bInterfaceProtocol = opts->protocol;
936 	hidg->report_length = opts->report_length;
937 	hidg->report_desc_length = opts->report_desc_length;
938 	if (opts->report_desc) {
939 		hidg->report_desc = kmemdup(opts->report_desc,
940 					    opts->report_desc_length,
941 					    GFP_KERNEL);
942 		if (!hidg->report_desc) {
943 			kfree(hidg);
944 			mutex_unlock(&opts->lock);
945 			return ERR_PTR(-ENOMEM);
946 		}
947 	}
948 
949 	mutex_unlock(&opts->lock);
950 
951 	hidg->func.name    = "hid";
952 	hidg->func.bind    = hidg_bind;
953 	hidg->func.unbind  = hidg_unbind;
954 	hidg->func.set_alt = hidg_set_alt;
955 	hidg->func.disable = hidg_disable;
956 	hidg->func.setup   = hidg_setup;
957 	hidg->func.free_func = hidg_free;
958 
959 	/* this could me made configurable at some point */
960 	hidg->qlen	   = 4;
961 
962 	return &hidg->func;
963 }
964 
965 DECLARE_USB_FUNCTION_INIT(hid, hidg_alloc_inst, hidg_alloc);
966 MODULE_LICENSE("GPL");
967 MODULE_AUTHOR("Fabien Chouteau");
968 
969 int ghid_setup(struct usb_gadget *g, int count)
970 {
971 	int status;
972 	dev_t dev;
973 
974 	hidg_class = class_create(THIS_MODULE, "hidg");
975 	if (IS_ERR(hidg_class)) {
976 		status = PTR_ERR(hidg_class);
977 		hidg_class = NULL;
978 		return status;
979 	}
980 
981 	status = alloc_chrdev_region(&dev, 0, count, "hidg");
982 	if (status) {
983 		class_destroy(hidg_class);
984 		hidg_class = NULL;
985 		return status;
986 	}
987 
988 	major = MAJOR(dev);
989 	minors = count;
990 
991 	return 0;
992 }
993 
994 void ghid_cleanup(void)
995 {
996 	if (major) {
997 		unregister_chrdev_region(MKDEV(major, 0), minors);
998 		major = minors = 0;
999 	}
1000 
1001 	class_destroy(hidg_class);
1002 	hidg_class = NULL;
1003 }
1004