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
25static int major, minors;
26
27static const struct class hidg_class = {
28	.name = "hidg",
29};
30
31static DEFINE_IDA(hidg_ida);
32static DEFINE_MUTEX(hidg_ida_lock); /* protects access to hidg_ida */
33
34/*-------------------------------------------------------------------------*/
35/*                            HID gadget struct                            */
36
37struct f_hidg_req_list {
38	struct usb_request	*req;
39	unsigned int		pos;
40	struct list_head 	list;
41};
42
43struct f_hidg {
44	/* configuration */
45	unsigned char			bInterfaceSubClass;
46	unsigned char			bInterfaceProtocol;
47	unsigned char			protocol;
48	unsigned char			idle;
49	unsigned short			report_desc_length;
50	char				*report_desc;
51	unsigned short			report_length;
52	/*
53	 * use_out_ep - if true, the OUT Endpoint (interrupt out method)
54	 *              will be used to receive reports from the host
55	 *              using functions with the "intout" suffix.
56	 *              Otherwise, the OUT Endpoint will not be configured
57	 *              and the SETUP/SET_REPORT method ("ssreport" suffix)
58	 *              will be used to receive reports.
59	 */
60	bool				use_out_ep;
61
62	/* recv report */
63	spinlock_t			read_spinlock;
64	wait_queue_head_t		read_queue;
65	/* recv report - interrupt out only (use_out_ep == 1) */
66	struct list_head		completed_out_req;
67	unsigned int			qlen;
68	/* recv report - setup set_report only (use_out_ep == 0) */
69	char				*set_report_buf;
70	unsigned int			set_report_length;
71
72	/* send report */
73	spinlock_t			write_spinlock;
74	bool				write_pending;
75	wait_queue_head_t		write_queue;
76	struct usb_request		*req;
77
78	struct device			dev;
79	struct cdev			cdev;
80	struct usb_function		func;
81
82	struct usb_ep			*in_ep;
83	struct usb_ep			*out_ep;
84};
85
86static inline struct f_hidg *func_to_hidg(struct usb_function *f)
87{
88	return container_of(f, struct f_hidg, func);
89}
90
91static void hidg_release(struct device *dev)
92{
93	struct f_hidg *hidg = container_of(dev, struct f_hidg, dev);
94
95	kfree(hidg->report_desc);
96	kfree(hidg->set_report_buf);
97	kfree(hidg);
98}
99
100/*-------------------------------------------------------------------------*/
101/*                           Static descriptors                            */
102
103static struct usb_interface_descriptor hidg_interface_desc = {
104	.bLength		= sizeof hidg_interface_desc,
105	.bDescriptorType	= USB_DT_INTERFACE,
106	/* .bInterfaceNumber	= DYNAMIC */
107	.bAlternateSetting	= 0,
108	/* .bNumEndpoints	= DYNAMIC (depends on use_out_ep) */
109	.bInterfaceClass	= USB_CLASS_HID,
110	/* .bInterfaceSubClass	= DYNAMIC */
111	/* .bInterfaceProtocol	= DYNAMIC */
112	/* .iInterface		= DYNAMIC */
113};
114
115static struct hid_descriptor hidg_desc = {
116	.bLength			= sizeof hidg_desc,
117	.bDescriptorType		= HID_DT_HID,
118	.bcdHID				= cpu_to_le16(0x0101),
119	.bCountryCode			= 0x00,
120	.bNumDescriptors		= 0x1,
121	/*.desc[0].bDescriptorType	= DYNAMIC */
122	/*.desc[0].wDescriptorLenght	= DYNAMIC */
123};
124
125/* Super-Speed Support */
126
127static struct usb_endpoint_descriptor hidg_ss_in_ep_desc = {
128	.bLength		= USB_DT_ENDPOINT_SIZE,
129	.bDescriptorType	= USB_DT_ENDPOINT,
130	.bEndpointAddress	= USB_DIR_IN,
131	.bmAttributes		= USB_ENDPOINT_XFER_INT,
132	/*.wMaxPacketSize	= DYNAMIC */
133	.bInterval		= 4, /* FIXME: Add this field in the
134				      * HID gadget configuration?
135				      * (struct hidg_func_descriptor)
136				      */
137};
138
139static struct usb_ss_ep_comp_descriptor hidg_ss_in_comp_desc = {
140	.bLength                = sizeof(hidg_ss_in_comp_desc),
141	.bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
142
143	/* .bMaxBurst           = 0, */
144	/* .bmAttributes        = 0, */
145	/* .wBytesPerInterval   = DYNAMIC */
146};
147
148static struct usb_endpoint_descriptor hidg_ss_out_ep_desc = {
149	.bLength		= USB_DT_ENDPOINT_SIZE,
150	.bDescriptorType	= USB_DT_ENDPOINT,
151	.bEndpointAddress	= USB_DIR_OUT,
152	.bmAttributes		= USB_ENDPOINT_XFER_INT,
153	/*.wMaxPacketSize	= DYNAMIC */
154	.bInterval		= 4, /* FIXME: Add this field in the
155				      * HID gadget configuration?
156				      * (struct hidg_func_descriptor)
157				      */
158};
159
160static struct usb_ss_ep_comp_descriptor hidg_ss_out_comp_desc = {
161	.bLength                = sizeof(hidg_ss_out_comp_desc),
162	.bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,
163
164	/* .bMaxBurst           = 0, */
165	/* .bmAttributes        = 0, */
166	/* .wBytesPerInterval   = DYNAMIC */
167};
168
169static struct usb_descriptor_header *hidg_ss_descriptors_intout[] = {
170	(struct usb_descriptor_header *)&hidg_interface_desc,
171	(struct usb_descriptor_header *)&hidg_desc,
172	(struct usb_descriptor_header *)&hidg_ss_in_ep_desc,
173	(struct usb_descriptor_header *)&hidg_ss_in_comp_desc,
174	(struct usb_descriptor_header *)&hidg_ss_out_ep_desc,
175	(struct usb_descriptor_header *)&hidg_ss_out_comp_desc,
176	NULL,
177};
178
179static struct usb_descriptor_header *hidg_ss_descriptors_ssreport[] = {
180	(struct usb_descriptor_header *)&hidg_interface_desc,
181	(struct usb_descriptor_header *)&hidg_desc,
182	(struct usb_descriptor_header *)&hidg_ss_in_ep_desc,
183	(struct usb_descriptor_header *)&hidg_ss_in_comp_desc,
184	NULL,
185};
186
187/* High-Speed Support */
188
189static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {
190	.bLength		= USB_DT_ENDPOINT_SIZE,
191	.bDescriptorType	= USB_DT_ENDPOINT,
192	.bEndpointAddress	= USB_DIR_IN,
193	.bmAttributes		= USB_ENDPOINT_XFER_INT,
194	/*.wMaxPacketSize	= DYNAMIC */
195	.bInterval		= 4, /* FIXME: Add this field in the
196				      * HID gadget configuration?
197				      * (struct hidg_func_descriptor)
198				      */
199};
200
201static struct usb_endpoint_descriptor hidg_hs_out_ep_desc = {
202	.bLength		= USB_DT_ENDPOINT_SIZE,
203	.bDescriptorType	= USB_DT_ENDPOINT,
204	.bEndpointAddress	= USB_DIR_OUT,
205	.bmAttributes		= USB_ENDPOINT_XFER_INT,
206	/*.wMaxPacketSize	= DYNAMIC */
207	.bInterval		= 4, /* FIXME: Add this field in the
208				      * HID gadget configuration?
209				      * (struct hidg_func_descriptor)
210				      */
211};
212
213static struct usb_descriptor_header *hidg_hs_descriptors_intout[] = {
214	(struct usb_descriptor_header *)&hidg_interface_desc,
215	(struct usb_descriptor_header *)&hidg_desc,
216	(struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
217	(struct usb_descriptor_header *)&hidg_hs_out_ep_desc,
218	NULL,
219};
220
221static struct usb_descriptor_header *hidg_hs_descriptors_ssreport[] = {
222	(struct usb_descriptor_header *)&hidg_interface_desc,
223	(struct usb_descriptor_header *)&hidg_desc,
224	(struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
225	NULL,
226};
227
228/* Full-Speed Support */
229
230static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {
231	.bLength		= USB_DT_ENDPOINT_SIZE,
232	.bDescriptorType	= USB_DT_ENDPOINT,
233	.bEndpointAddress	= USB_DIR_IN,
234	.bmAttributes		= USB_ENDPOINT_XFER_INT,
235	/*.wMaxPacketSize	= DYNAMIC */
236	.bInterval		= 10, /* FIXME: Add this field in the
237				       * HID gadget configuration?
238				       * (struct hidg_func_descriptor)
239				       */
240};
241
242static struct usb_endpoint_descriptor hidg_fs_out_ep_desc = {
243	.bLength		= USB_DT_ENDPOINT_SIZE,
244	.bDescriptorType	= USB_DT_ENDPOINT,
245	.bEndpointAddress	= USB_DIR_OUT,
246	.bmAttributes		= USB_ENDPOINT_XFER_INT,
247	/*.wMaxPacketSize	= DYNAMIC */
248	.bInterval		= 10, /* FIXME: Add this field in the
249				       * HID gadget configuration?
250				       * (struct hidg_func_descriptor)
251				       */
252};
253
254static struct usb_descriptor_header *hidg_fs_descriptors_intout[] = {
255	(struct usb_descriptor_header *)&hidg_interface_desc,
256	(struct usb_descriptor_header *)&hidg_desc,
257	(struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
258	(struct usb_descriptor_header *)&hidg_fs_out_ep_desc,
259	NULL,
260};
261
262static struct usb_descriptor_header *hidg_fs_descriptors_ssreport[] = {
263	(struct usb_descriptor_header *)&hidg_interface_desc,
264	(struct usb_descriptor_header *)&hidg_desc,
265	(struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
266	NULL,
267};
268
269/*-------------------------------------------------------------------------*/
270/*                                 Strings                                 */
271
272#define CT_FUNC_HID_IDX	0
273
274static struct usb_string ct_func_string_defs[] = {
275	[CT_FUNC_HID_IDX].s	= "HID Interface",
276	{},			/* end of list */
277};
278
279static struct usb_gadget_strings ct_func_string_table = {
280	.language	= 0x0409,	/* en-US */
281	.strings	= ct_func_string_defs,
282};
283
284static struct usb_gadget_strings *ct_func_strings[] = {
285	&ct_func_string_table,
286	NULL,
287};
288
289/*-------------------------------------------------------------------------*/
290/*                              Char Device                                */
291
292static ssize_t f_hidg_intout_read(struct file *file, char __user *buffer,
293				  size_t count, loff_t *ptr)
294{
295	struct f_hidg *hidg = file->private_data;
296	struct f_hidg_req_list *list;
297	struct usb_request *req;
298	unsigned long flags;
299	int ret;
300
301	if (!count)
302		return 0;
303
304	spin_lock_irqsave(&hidg->read_spinlock, flags);
305
306#define READ_COND_INTOUT (!list_empty(&hidg->completed_out_req))
307
308	/* wait for at least one buffer to complete */
309	while (!READ_COND_INTOUT) {
310		spin_unlock_irqrestore(&hidg->read_spinlock, flags);
311		if (file->f_flags & O_NONBLOCK)
312			return -EAGAIN;
313
314		if (wait_event_interruptible(hidg->read_queue, READ_COND_INTOUT))
315			return -ERESTARTSYS;
316
317		spin_lock_irqsave(&hidg->read_spinlock, flags);
318	}
319
320	/* pick the first one */
321	list = list_first_entry(&hidg->completed_out_req,
322				struct f_hidg_req_list, list);
323
324	/*
325	 * Remove this from list to protect it from beign free()
326	 * while host disables our function
327	 */
328	list_del(&list->list);
329
330	req = list->req;
331	count = min_t(unsigned int, count, req->actual - list->pos);
332	spin_unlock_irqrestore(&hidg->read_spinlock, flags);
333
334	/* copy to user outside spinlock */
335	count -= copy_to_user(buffer, req->buf + list->pos, count);
336	list->pos += count;
337
338	/*
339	 * if this request is completely handled and transfered to
340	 * userspace, remove its entry from the list and requeue it
341	 * again. Otherwise, we will revisit it again upon the next
342	 * call, taking into account its current read position.
343	 */
344	if (list->pos == req->actual) {
345		kfree(list);
346
347		req->length = hidg->report_length;
348		ret = usb_ep_queue(hidg->out_ep, req, GFP_KERNEL);
349		if (ret < 0) {
350			free_ep_req(hidg->out_ep, req);
351			return ret;
352		}
353	} else {
354		spin_lock_irqsave(&hidg->read_spinlock, flags);
355		list_add(&list->list, &hidg->completed_out_req);
356		spin_unlock_irqrestore(&hidg->read_spinlock, flags);
357
358		wake_up(&hidg->read_queue);
359	}
360
361	return count;
362}
363
364#define READ_COND_SSREPORT (hidg->set_report_buf != NULL)
365
366static ssize_t f_hidg_ssreport_read(struct file *file, char __user *buffer,
367				    size_t count, loff_t *ptr)
368{
369	struct f_hidg *hidg = file->private_data;
370	char *tmp_buf = NULL;
371	unsigned long flags;
372
373	if (!count)
374		return 0;
375
376	spin_lock_irqsave(&hidg->read_spinlock, flags);
377
378	while (!READ_COND_SSREPORT) {
379		spin_unlock_irqrestore(&hidg->read_spinlock, flags);
380		if (file->f_flags & O_NONBLOCK)
381			return -EAGAIN;
382
383		if (wait_event_interruptible(hidg->read_queue, READ_COND_SSREPORT))
384			return -ERESTARTSYS;
385
386		spin_lock_irqsave(&hidg->read_spinlock, flags);
387	}
388
389	count = min_t(unsigned int, count, hidg->set_report_length);
390	tmp_buf = hidg->set_report_buf;
391	hidg->set_report_buf = NULL;
392
393	spin_unlock_irqrestore(&hidg->read_spinlock, flags);
394
395	if (tmp_buf != NULL) {
396		count -= copy_to_user(buffer, tmp_buf, count);
397		kfree(tmp_buf);
398	} else {
399		count = -ENOMEM;
400	}
401
402	wake_up(&hidg->read_queue);
403
404	return count;
405}
406
407static ssize_t f_hidg_read(struct file *file, char __user *buffer,
408			   size_t count, loff_t *ptr)
409{
410	struct f_hidg *hidg = file->private_data;
411
412	if (hidg->use_out_ep)
413		return f_hidg_intout_read(file, buffer, count, ptr);
414	else
415		return f_hidg_ssreport_read(file, buffer, count, ptr);
416}
417
418static void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req)
419{
420	struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;
421	unsigned long flags;
422
423	if (req->status != 0) {
424		ERROR(hidg->func.config->cdev,
425			"End Point Request ERROR: %d\n", req->status);
426	}
427
428	spin_lock_irqsave(&hidg->write_spinlock, flags);
429	hidg->write_pending = 0;
430	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
431	wake_up(&hidg->write_queue);
432}
433
434static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
435			    size_t count, loff_t *offp)
436{
437	struct f_hidg *hidg  = file->private_data;
438	struct usb_request *req;
439	unsigned long flags;
440	ssize_t status = -ENOMEM;
441
442	spin_lock_irqsave(&hidg->write_spinlock, flags);
443
444	if (!hidg->req) {
445		spin_unlock_irqrestore(&hidg->write_spinlock, flags);
446		return -ESHUTDOWN;
447	}
448
449#define WRITE_COND (!hidg->write_pending)
450try_again:
451	/* write queue */
452	while (!WRITE_COND) {
453		spin_unlock_irqrestore(&hidg->write_spinlock, flags);
454		if (file->f_flags & O_NONBLOCK)
455			return -EAGAIN;
456
457		if (wait_event_interruptible_exclusive(
458				hidg->write_queue, WRITE_COND))
459			return -ERESTARTSYS;
460
461		spin_lock_irqsave(&hidg->write_spinlock, flags);
462	}
463
464	hidg->write_pending = 1;
465	req = hidg->req;
466	count  = min_t(unsigned, count, hidg->report_length);
467
468	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
469
470	if (!req) {
471		ERROR(hidg->func.config->cdev, "hidg->req is NULL\n");
472		status = -ESHUTDOWN;
473		goto release_write_pending;
474	}
475
476	status = copy_from_user(req->buf, buffer, count);
477	if (status != 0) {
478		ERROR(hidg->func.config->cdev,
479			"copy_from_user error\n");
480		status = -EINVAL;
481		goto release_write_pending;
482	}
483
484	spin_lock_irqsave(&hidg->write_spinlock, flags);
485
486	/* when our function has been disabled by host */
487	if (!hidg->req) {
488		free_ep_req(hidg->in_ep, req);
489		/*
490		 * TODO
491		 * Should we fail with error here?
492		 */
493		goto try_again;
494	}
495
496	req->status   = 0;
497	req->zero     = 0;
498	req->length   = count;
499	req->complete = f_hidg_req_complete;
500	req->context  = hidg;
501
502	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
503
504	if (!hidg->in_ep->enabled) {
505		ERROR(hidg->func.config->cdev, "in_ep is disabled\n");
506		status = -ESHUTDOWN;
507		goto release_write_pending;
508	}
509
510	status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC);
511	if (status < 0)
512		goto release_write_pending;
513	else
514		status = count;
515
516	return status;
517release_write_pending:
518	spin_lock_irqsave(&hidg->write_spinlock, flags);
519	hidg->write_pending = 0;
520	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
521
522	wake_up(&hidg->write_queue);
523
524	return status;
525}
526
527static __poll_t f_hidg_poll(struct file *file, poll_table *wait)
528{
529	struct f_hidg	*hidg  = file->private_data;
530	__poll_t	ret = 0;
531
532	poll_wait(file, &hidg->read_queue, wait);
533	poll_wait(file, &hidg->write_queue, wait);
534
535	if (WRITE_COND)
536		ret |= EPOLLOUT | EPOLLWRNORM;
537
538	if (hidg->use_out_ep) {
539		if (READ_COND_INTOUT)
540			ret |= EPOLLIN | EPOLLRDNORM;
541	} else {
542		if (READ_COND_SSREPORT)
543			ret |= EPOLLIN | EPOLLRDNORM;
544	}
545
546	return ret;
547}
548
549#undef WRITE_COND
550#undef READ_COND_SSREPORT
551#undef READ_COND_INTOUT
552
553static int f_hidg_release(struct inode *inode, struct file *fd)
554{
555	fd->private_data = NULL;
556	return 0;
557}
558
559static int f_hidg_open(struct inode *inode, struct file *fd)
560{
561	struct f_hidg *hidg =
562		container_of(inode->i_cdev, struct f_hidg, cdev);
563
564	fd->private_data = hidg;
565
566	return 0;
567}
568
569/*-------------------------------------------------------------------------*/
570/*                                usb_function                             */
571
572static inline struct usb_request *hidg_alloc_ep_req(struct usb_ep *ep,
573						    unsigned length)
574{
575	return alloc_ep_req(ep, length);
576}
577
578static void hidg_intout_complete(struct usb_ep *ep, struct usb_request *req)
579{
580	struct f_hidg *hidg = (struct f_hidg *) req->context;
581	struct usb_composite_dev *cdev = hidg->func.config->cdev;
582	struct f_hidg_req_list *req_list;
583	unsigned long flags;
584
585	switch (req->status) {
586	case 0:
587		req_list = kzalloc(sizeof(*req_list), GFP_ATOMIC);
588		if (!req_list) {
589			ERROR(cdev, "Unable to allocate mem for req_list\n");
590			goto free_req;
591		}
592
593		req_list->req = req;
594
595		spin_lock_irqsave(&hidg->read_spinlock, flags);
596		list_add_tail(&req_list->list, &hidg->completed_out_req);
597		spin_unlock_irqrestore(&hidg->read_spinlock, flags);
598
599		wake_up(&hidg->read_queue);
600		break;
601	default:
602		ERROR(cdev, "Set report failed %d\n", req->status);
603		fallthrough;
604	case -ECONNABORTED:		/* hardware forced ep reset */
605	case -ECONNRESET:		/* request dequeued */
606	case -ESHUTDOWN:		/* disconnect from host */
607free_req:
608		free_ep_req(ep, req);
609		return;
610	}
611}
612
613static void hidg_ssreport_complete(struct usb_ep *ep, struct usb_request *req)
614{
615	struct f_hidg *hidg = (struct f_hidg *)req->context;
616	struct usb_composite_dev *cdev = hidg->func.config->cdev;
617	char *new_buf = NULL;
618	unsigned long flags;
619
620	if (req->status != 0 || req->buf == NULL || req->actual == 0) {
621		ERROR(cdev,
622		      "%s FAILED: status=%d, buf=%p, actual=%d\n",
623		      __func__, req->status, req->buf, req->actual);
624		return;
625	}
626
627	spin_lock_irqsave(&hidg->read_spinlock, flags);
628
629	new_buf = krealloc(hidg->set_report_buf, req->actual, GFP_ATOMIC);
630	if (new_buf == NULL) {
631		spin_unlock_irqrestore(&hidg->read_spinlock, flags);
632		return;
633	}
634	hidg->set_report_buf = new_buf;
635
636	hidg->set_report_length = req->actual;
637	memcpy(hidg->set_report_buf, req->buf, req->actual);
638
639	spin_unlock_irqrestore(&hidg->read_spinlock, flags);
640
641	wake_up(&hidg->read_queue);
642}
643
644static int hidg_setup(struct usb_function *f,
645		const struct usb_ctrlrequest *ctrl)
646{
647	struct f_hidg			*hidg = func_to_hidg(f);
648	struct usb_composite_dev	*cdev = f->config->cdev;
649	struct usb_request		*req  = cdev->req;
650	int status = 0;
651	__u16 value, length;
652
653	value	= __le16_to_cpu(ctrl->wValue);
654	length	= __le16_to_cpu(ctrl->wLength);
655
656	VDBG(cdev,
657	     "%s crtl_request : bRequestType:0x%x bRequest:0x%x Value:0x%x\n",
658	     __func__, ctrl->bRequestType, ctrl->bRequest, value);
659
660	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
661	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
662		  | HID_REQ_GET_REPORT):
663		VDBG(cdev, "get_report\n");
664
665		/* send an empty report */
666		length = min_t(unsigned, length, hidg->report_length);
667		memset(req->buf, 0x0, length);
668
669		goto respond;
670		break;
671
672	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
673		  | HID_REQ_GET_PROTOCOL):
674		VDBG(cdev, "get_protocol\n");
675		length = min_t(unsigned int, length, 1);
676		((u8 *) req->buf)[0] = hidg->protocol;
677		goto respond;
678		break;
679
680	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
681		  | HID_REQ_GET_IDLE):
682		VDBG(cdev, "get_idle\n");
683		length = min_t(unsigned int, length, 1);
684		((u8 *) req->buf)[0] = hidg->idle;
685		goto respond;
686		break;
687
688	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
689		  | HID_REQ_SET_REPORT):
690		VDBG(cdev, "set_report | wLength=%d\n", ctrl->wLength);
691		if (hidg->use_out_ep)
692			goto stall;
693		req->complete = hidg_ssreport_complete;
694		req->context  = hidg;
695		goto respond;
696		break;
697
698	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
699		  | HID_REQ_SET_PROTOCOL):
700		VDBG(cdev, "set_protocol\n");
701		if (value > HID_REPORT_PROTOCOL)
702			goto stall;
703		length = 0;
704		/*
705		 * We assume that programs implementing the Boot protocol
706		 * are also compatible with the Report Protocol
707		 */
708		if (hidg->bInterfaceSubClass == USB_INTERFACE_SUBCLASS_BOOT) {
709			hidg->protocol = value;
710			goto respond;
711		}
712		goto stall;
713		break;
714
715	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
716		  | HID_REQ_SET_IDLE):
717		VDBG(cdev, "set_idle\n");
718		length = 0;
719		hidg->idle = value >> 8;
720		goto respond;
721		break;
722
723	case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8
724		  | USB_REQ_GET_DESCRIPTOR):
725		switch (value >> 8) {
726		case HID_DT_HID:
727		{
728			struct hid_descriptor hidg_desc_copy = hidg_desc;
729
730			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: HID\n");
731			hidg_desc_copy.desc[0].bDescriptorType = HID_DT_REPORT;
732			hidg_desc_copy.desc[0].wDescriptorLength =
733				cpu_to_le16(hidg->report_desc_length);
734
735			length = min_t(unsigned short, length,
736						   hidg_desc_copy.bLength);
737			memcpy(req->buf, &hidg_desc_copy, length);
738			goto respond;
739			break;
740		}
741		case HID_DT_REPORT:
742			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");
743			length = min_t(unsigned short, length,
744						   hidg->report_desc_length);
745			memcpy(req->buf, hidg->report_desc, length);
746			goto respond;
747			break;
748
749		default:
750			VDBG(cdev, "Unknown descriptor request 0x%x\n",
751				 value >> 8);
752			goto stall;
753			break;
754		}
755		break;
756
757	default:
758		VDBG(cdev, "Unknown request 0x%x\n",
759			 ctrl->bRequest);
760		goto stall;
761		break;
762	}
763
764stall:
765	return -EOPNOTSUPP;
766
767respond:
768	req->zero = 0;
769	req->length = length;
770	status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
771	if (status < 0)
772		ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);
773	return status;
774}
775
776static void hidg_disable(struct usb_function *f)
777{
778	struct f_hidg *hidg = func_to_hidg(f);
779	struct f_hidg_req_list *list, *next;
780	unsigned long flags;
781
782	usb_ep_disable(hidg->in_ep);
783
784	if (hidg->out_ep) {
785		usb_ep_disable(hidg->out_ep);
786
787		spin_lock_irqsave(&hidg->read_spinlock, flags);
788		list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {
789			free_ep_req(hidg->out_ep, list->req);
790			list_del(&list->list);
791			kfree(list);
792		}
793		spin_unlock_irqrestore(&hidg->read_spinlock, flags);
794	}
795
796	spin_lock_irqsave(&hidg->write_spinlock, flags);
797	if (!hidg->write_pending) {
798		free_ep_req(hidg->in_ep, hidg->req);
799		hidg->write_pending = 1;
800	}
801
802	hidg->req = NULL;
803	spin_unlock_irqrestore(&hidg->write_spinlock, flags);
804}
805
806static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
807{
808	struct usb_composite_dev		*cdev = f->config->cdev;
809	struct f_hidg				*hidg = func_to_hidg(f);
810	struct usb_request			*req_in = NULL;
811	unsigned long				flags;
812	int i, status = 0;
813
814	VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);
815
816	if (hidg->in_ep != NULL) {
817		/* restart endpoint */
818		usb_ep_disable(hidg->in_ep);
819
820		status = config_ep_by_speed(f->config->cdev->gadget, f,
821					    hidg->in_ep);
822		if (status) {
823			ERROR(cdev, "config_ep_by_speed FAILED!\n");
824			goto fail;
825		}
826		status = usb_ep_enable(hidg->in_ep);
827		if (status < 0) {
828			ERROR(cdev, "Enable IN endpoint FAILED!\n");
829			goto fail;
830		}
831		hidg->in_ep->driver_data = hidg;
832
833		req_in = hidg_alloc_ep_req(hidg->in_ep, hidg->report_length);
834		if (!req_in) {
835			status = -ENOMEM;
836			goto disable_ep_in;
837		}
838	}
839
840	if (hidg->use_out_ep && hidg->out_ep != NULL) {
841		/* restart endpoint */
842		usb_ep_disable(hidg->out_ep);
843
844		status = config_ep_by_speed(f->config->cdev->gadget, f,
845					    hidg->out_ep);
846		if (status) {
847			ERROR(cdev, "config_ep_by_speed FAILED!\n");
848			goto free_req_in;
849		}
850		status = usb_ep_enable(hidg->out_ep);
851		if (status < 0) {
852			ERROR(cdev, "Enable OUT endpoint FAILED!\n");
853			goto free_req_in;
854		}
855		hidg->out_ep->driver_data = hidg;
856
857		/*
858		 * allocate a bunch of read buffers and queue them all at once.
859		 */
860		for (i = 0; i < hidg->qlen && status == 0; i++) {
861			struct usb_request *req =
862					hidg_alloc_ep_req(hidg->out_ep,
863							  hidg->report_length);
864			if (req) {
865				req->complete = hidg_intout_complete;
866				req->context  = hidg;
867				status = usb_ep_queue(hidg->out_ep, req,
868						      GFP_ATOMIC);
869				if (status) {
870					ERROR(cdev, "%s queue req --> %d\n",
871						hidg->out_ep->name, status);
872					free_ep_req(hidg->out_ep, req);
873				}
874			} else {
875				status = -ENOMEM;
876				goto disable_out_ep;
877			}
878		}
879	}
880
881	if (hidg->in_ep != NULL) {
882		spin_lock_irqsave(&hidg->write_spinlock, flags);
883		hidg->req = req_in;
884		hidg->write_pending = 0;
885		spin_unlock_irqrestore(&hidg->write_spinlock, flags);
886
887		wake_up(&hidg->write_queue);
888	}
889	return 0;
890disable_out_ep:
891	if (hidg->out_ep)
892		usb_ep_disable(hidg->out_ep);
893free_req_in:
894	if (req_in)
895		free_ep_req(hidg->in_ep, req_in);
896
897disable_ep_in:
898	if (hidg->in_ep)
899		usb_ep_disable(hidg->in_ep);
900
901fail:
902	return status;
903}
904
905static const struct file_operations f_hidg_fops = {
906	.owner		= THIS_MODULE,
907	.open		= f_hidg_open,
908	.release	= f_hidg_release,
909	.write		= f_hidg_write,
910	.read		= f_hidg_read,
911	.poll		= f_hidg_poll,
912	.llseek		= noop_llseek,
913};
914
915static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
916{
917	struct usb_ep		*ep;
918	struct f_hidg		*hidg = func_to_hidg(f);
919	struct usb_string	*us;
920	int			status;
921
922	/* maybe allocate device-global string IDs, and patch descriptors */
923	us = usb_gstrings_attach(c->cdev, ct_func_strings,
924				 ARRAY_SIZE(ct_func_string_defs));
925	if (IS_ERR(us))
926		return PTR_ERR(us);
927	hidg_interface_desc.iInterface = us[CT_FUNC_HID_IDX].id;
928
929	/* allocate instance-specific interface IDs, and patch descriptors */
930	status = usb_interface_id(c, f);
931	if (status < 0)
932		goto fail;
933	hidg_interface_desc.bInterfaceNumber = status;
934
935	/* allocate instance-specific endpoints */
936	status = -ENODEV;
937	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
938	if (!ep)
939		goto fail;
940	hidg->in_ep = ep;
941
942	hidg->out_ep = NULL;
943	if (hidg->use_out_ep) {
944		ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc);
945		if (!ep)
946			goto fail;
947		hidg->out_ep = ep;
948	}
949
950	/* used only if use_out_ep == 1 */
951	hidg->set_report_buf = NULL;
952
953	/* set descriptor dynamic values */
954	hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
955	hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
956	hidg_interface_desc.bNumEndpoints = hidg->use_out_ep ? 2 : 1;
957	hidg->protocol = HID_REPORT_PROTOCOL;
958	hidg->idle = 1;
959	hidg_ss_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
960	hidg_ss_in_comp_desc.wBytesPerInterval =
961				cpu_to_le16(hidg->report_length);
962	hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
963	hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
964	hidg_ss_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
965	hidg_ss_out_comp_desc.wBytesPerInterval =
966				cpu_to_le16(hidg->report_length);
967	hidg_hs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
968	hidg_fs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
969	/*
970	 * We can use hidg_desc struct here but we should not relay
971	 * that its content won't change after returning from this function.
972	 */
973	hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
974	hidg_desc.desc[0].wDescriptorLength =
975		cpu_to_le16(hidg->report_desc_length);
976
977	hidg_hs_in_ep_desc.bEndpointAddress =
978		hidg_fs_in_ep_desc.bEndpointAddress;
979	hidg_hs_out_ep_desc.bEndpointAddress =
980		hidg_fs_out_ep_desc.bEndpointAddress;
981
982	hidg_ss_in_ep_desc.bEndpointAddress =
983		hidg_fs_in_ep_desc.bEndpointAddress;
984	hidg_ss_out_ep_desc.bEndpointAddress =
985		hidg_fs_out_ep_desc.bEndpointAddress;
986
987	if (hidg->use_out_ep)
988		status = usb_assign_descriptors(f,
989			hidg_fs_descriptors_intout,
990			hidg_hs_descriptors_intout,
991			hidg_ss_descriptors_intout,
992			hidg_ss_descriptors_intout);
993	else
994		status = usb_assign_descriptors(f,
995			hidg_fs_descriptors_ssreport,
996			hidg_hs_descriptors_ssreport,
997			hidg_ss_descriptors_ssreport,
998			hidg_ss_descriptors_ssreport);
999
1000	if (status)
1001		goto fail;
1002
1003	spin_lock_init(&hidg->write_spinlock);
1004	hidg->write_pending = 1;
1005	hidg->req = NULL;
1006	spin_lock_init(&hidg->read_spinlock);
1007	init_waitqueue_head(&hidg->write_queue);
1008	init_waitqueue_head(&hidg->read_queue);
1009	INIT_LIST_HEAD(&hidg->completed_out_req);
1010
1011	/* create char device */
1012	cdev_init(&hidg->cdev, &f_hidg_fops);
1013	status = cdev_device_add(&hidg->cdev, &hidg->dev);
1014	if (status)
1015		goto fail_free_descs;
1016
1017	return 0;
1018fail_free_descs:
1019	usb_free_all_descriptors(f);
1020fail:
1021	ERROR(f->config->cdev, "hidg_bind FAILED\n");
1022	if (hidg->req != NULL)
1023		free_ep_req(hidg->in_ep, hidg->req);
1024
1025	return status;
1026}
1027
1028static inline int hidg_get_minor(void)
1029{
1030	int ret;
1031
1032	ret = ida_simple_get(&hidg_ida, 0, 0, GFP_KERNEL);
1033	if (ret >= HIDG_MINORS) {
1034		ida_simple_remove(&hidg_ida, ret);
1035		ret = -ENODEV;
1036	}
1037
1038	return ret;
1039}
1040
1041static inline struct f_hid_opts *to_f_hid_opts(struct config_item *item)
1042{
1043	return container_of(to_config_group(item), struct f_hid_opts,
1044			    func_inst.group);
1045}
1046
1047static void hid_attr_release(struct config_item *item)
1048{
1049	struct f_hid_opts *opts = to_f_hid_opts(item);
1050
1051	usb_put_function_instance(&opts->func_inst);
1052}
1053
1054static struct configfs_item_operations hidg_item_ops = {
1055	.release	= hid_attr_release,
1056};
1057
1058#define F_HID_OPT(name, prec, limit)					\
1059static ssize_t f_hid_opts_##name##_show(struct config_item *item, char *page)\
1060{									\
1061	struct f_hid_opts *opts = to_f_hid_opts(item);			\
1062	int result;							\
1063									\
1064	mutex_lock(&opts->lock);					\
1065	result = sprintf(page, "%d\n", opts->name);			\
1066	mutex_unlock(&opts->lock);					\
1067									\
1068	return result;							\
1069}									\
1070									\
1071static ssize_t f_hid_opts_##name##_store(struct config_item *item,	\
1072					 const char *page, size_t len)	\
1073{									\
1074	struct f_hid_opts *opts = to_f_hid_opts(item);			\
1075	int ret;							\
1076	u##prec num;							\
1077									\
1078	mutex_lock(&opts->lock);					\
1079	if (opts->refcnt) {						\
1080		ret = -EBUSY;						\
1081		goto end;						\
1082	}								\
1083									\
1084	ret = kstrtou##prec(page, 0, &num);				\
1085	if (ret)							\
1086		goto end;						\
1087									\
1088	if (num > limit) {						\
1089		ret = -EINVAL;						\
1090		goto end;						\
1091	}								\
1092	opts->name = num;						\
1093	ret = len;							\
1094									\
1095end:									\
1096	mutex_unlock(&opts->lock);					\
1097	return ret;							\
1098}									\
1099									\
1100CONFIGFS_ATTR(f_hid_opts_, name)
1101
1102F_HID_OPT(subclass, 8, 255);
1103F_HID_OPT(protocol, 8, 255);
1104F_HID_OPT(no_out_endpoint, 8, 1);
1105F_HID_OPT(report_length, 16, 65535);
1106
1107static ssize_t f_hid_opts_report_desc_show(struct config_item *item, char *page)
1108{
1109	struct f_hid_opts *opts = to_f_hid_opts(item);
1110	int result;
1111
1112	mutex_lock(&opts->lock);
1113	result = opts->report_desc_length;
1114	memcpy(page, opts->report_desc, opts->report_desc_length);
1115	mutex_unlock(&opts->lock);
1116
1117	return result;
1118}
1119
1120static ssize_t f_hid_opts_report_desc_store(struct config_item *item,
1121					    const char *page, size_t len)
1122{
1123	struct f_hid_opts *opts = to_f_hid_opts(item);
1124	int ret = -EBUSY;
1125	char *d;
1126
1127	mutex_lock(&opts->lock);
1128
1129	if (opts->refcnt)
1130		goto end;
1131	if (len > PAGE_SIZE) {
1132		ret = -ENOSPC;
1133		goto end;
1134	}
1135	d = kmemdup(page, len, GFP_KERNEL);
1136	if (!d) {
1137		ret = -ENOMEM;
1138		goto end;
1139	}
1140	kfree(opts->report_desc);
1141	opts->report_desc = d;
1142	opts->report_desc_length = len;
1143	opts->report_desc_alloc = true;
1144	ret = len;
1145end:
1146	mutex_unlock(&opts->lock);
1147	return ret;
1148}
1149
1150CONFIGFS_ATTR(f_hid_opts_, report_desc);
1151
1152static ssize_t f_hid_opts_dev_show(struct config_item *item, char *page)
1153{
1154	struct f_hid_opts *opts = to_f_hid_opts(item);
1155
1156	return sprintf(page, "%d:%d\n", major, opts->minor);
1157}
1158
1159CONFIGFS_ATTR_RO(f_hid_opts_, dev);
1160
1161static struct configfs_attribute *hid_attrs[] = {
1162	&f_hid_opts_attr_subclass,
1163	&f_hid_opts_attr_protocol,
1164	&f_hid_opts_attr_no_out_endpoint,
1165	&f_hid_opts_attr_report_length,
1166	&f_hid_opts_attr_report_desc,
1167	&f_hid_opts_attr_dev,
1168	NULL,
1169};
1170
1171static const struct config_item_type hid_func_type = {
1172	.ct_item_ops	= &hidg_item_ops,
1173	.ct_attrs	= hid_attrs,
1174	.ct_owner	= THIS_MODULE,
1175};
1176
1177static inline void hidg_put_minor(int minor)
1178{
1179	ida_simple_remove(&hidg_ida, minor);
1180}
1181
1182static void hidg_free_inst(struct usb_function_instance *f)
1183{
1184	struct f_hid_opts *opts;
1185
1186	opts = container_of(f, struct f_hid_opts, func_inst);
1187
1188	mutex_lock(&hidg_ida_lock);
1189
1190	hidg_put_minor(opts->minor);
1191	if (ida_is_empty(&hidg_ida))
1192		ghid_cleanup();
1193
1194	mutex_unlock(&hidg_ida_lock);
1195
1196	if (opts->report_desc_alloc)
1197		kfree(opts->report_desc);
1198
1199	kfree(opts);
1200}
1201
1202static struct usb_function_instance *hidg_alloc_inst(void)
1203{
1204	struct f_hid_opts *opts;
1205	struct usb_function_instance *ret;
1206	int status = 0;
1207
1208	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1209	if (!opts)
1210		return ERR_PTR(-ENOMEM);
1211	mutex_init(&opts->lock);
1212	opts->func_inst.free_func_inst = hidg_free_inst;
1213	ret = &opts->func_inst;
1214
1215	mutex_lock(&hidg_ida_lock);
1216
1217	if (ida_is_empty(&hidg_ida)) {
1218		status = ghid_setup(NULL, HIDG_MINORS);
1219		if (status)  {
1220			ret = ERR_PTR(status);
1221			kfree(opts);
1222			goto unlock;
1223		}
1224	}
1225
1226	opts->minor = hidg_get_minor();
1227	if (opts->minor < 0) {
1228		ret = ERR_PTR(opts->minor);
1229		kfree(opts);
1230		if (ida_is_empty(&hidg_ida))
1231			ghid_cleanup();
1232		goto unlock;
1233	}
1234	config_group_init_type_name(&opts->func_inst.group, "", &hid_func_type);
1235
1236unlock:
1237	mutex_unlock(&hidg_ida_lock);
1238	return ret;
1239}
1240
1241static void hidg_free(struct usb_function *f)
1242{
1243	struct f_hidg *hidg;
1244	struct f_hid_opts *opts;
1245
1246	hidg = func_to_hidg(f);
1247	opts = container_of(f->fi, struct f_hid_opts, func_inst);
1248	put_device(&hidg->dev);
1249	mutex_lock(&opts->lock);
1250	--opts->refcnt;
1251	mutex_unlock(&opts->lock);
1252}
1253
1254static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
1255{
1256	struct f_hidg *hidg = func_to_hidg(f);
1257
1258	cdev_device_del(&hidg->cdev, &hidg->dev);
1259
1260	usb_free_all_descriptors(f);
1261}
1262
1263static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
1264{
1265	struct f_hidg *hidg;
1266	struct f_hid_opts *opts;
1267	int ret;
1268
1269	/* allocate and initialize one new instance */
1270	hidg = kzalloc(sizeof(*hidg), GFP_KERNEL);
1271	if (!hidg)
1272		return ERR_PTR(-ENOMEM);
1273
1274	opts = container_of(fi, struct f_hid_opts, func_inst);
1275
1276	mutex_lock(&opts->lock);
1277
1278	device_initialize(&hidg->dev);
1279	hidg->dev.release = hidg_release;
1280	hidg->dev.class = &hidg_class;
1281	hidg->dev.devt = MKDEV(major, opts->minor);
1282	ret = dev_set_name(&hidg->dev, "hidg%d", opts->minor);
1283	if (ret)
1284		goto err_unlock;
1285
1286	hidg->bInterfaceSubClass = opts->subclass;
1287	hidg->bInterfaceProtocol = opts->protocol;
1288	hidg->report_length = opts->report_length;
1289	hidg->report_desc_length = opts->report_desc_length;
1290	if (opts->report_desc) {
1291		hidg->report_desc = kmemdup(opts->report_desc,
1292					    opts->report_desc_length,
1293					    GFP_KERNEL);
1294		if (!hidg->report_desc) {
1295			ret = -ENOMEM;
1296			goto err_put_device;
1297		}
1298	}
1299	hidg->use_out_ep = !opts->no_out_endpoint;
1300
1301	++opts->refcnt;
1302	mutex_unlock(&opts->lock);
1303
1304	hidg->func.name    = "hid";
1305	hidg->func.bind    = hidg_bind;
1306	hidg->func.unbind  = hidg_unbind;
1307	hidg->func.set_alt = hidg_set_alt;
1308	hidg->func.disable = hidg_disable;
1309	hidg->func.setup   = hidg_setup;
1310	hidg->func.free_func = hidg_free;
1311
1312	/* this could be made configurable at some point */
1313	hidg->qlen	   = 4;
1314
1315	return &hidg->func;
1316
1317err_put_device:
1318	put_device(&hidg->dev);
1319err_unlock:
1320	mutex_unlock(&opts->lock);
1321	return ERR_PTR(ret);
1322}
1323
1324DECLARE_USB_FUNCTION_INIT(hid, hidg_alloc_inst, hidg_alloc);
1325MODULE_LICENSE("GPL");
1326MODULE_AUTHOR("Fabien Chouteau");
1327
1328int ghid_setup(struct usb_gadget *g, int count)
1329{
1330	int status;
1331	dev_t dev;
1332
1333	status = class_register(&hidg_class);
1334	if (status)
1335		return status;
1336
1337	status = alloc_chrdev_region(&dev, 0, count, "hidg");
1338	if (status) {
1339		class_unregister(&hidg_class);
1340		return status;
1341	}
1342
1343	major = MAJOR(dev);
1344	minors = count;
1345
1346	return 0;
1347}
1348
1349void ghid_cleanup(void)
1350{
1351	if (major) {
1352		unregister_chrdev_region(MKDEV(major, 0), minors);
1353		major = minors = 0;
1354	}
1355
1356	class_unregister(&hidg_class);
1357}
1358