summaryrefslogtreecommitdiff
path: root/drivers/usb/gadget/function/f_eem.c
blob: cad35a502d3f73a64759cd8eb8d541d36104cbac (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
/*
 * f_eem.c -- USB CDC Ethernet (EEM) link function driver
 *
 * Copyright (C) 2003-2005,2008 David Brownell
 * Copyright (C) 2008 Nokia Corporation
 * Copyright (C) 2009 EF Johnson Technologies
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/etherdevice.h>
#include <linux/crc32.h>
#include <linux/slab.h>

#include "u_ether.h"
#include "u_ether_configfs.h"
#include "u_eem.h"

#define EEM_HLEN 2

/*
 * This function is a "CDC Ethernet Emulation Model" (CDC EEM)
 * Ethernet link.
 */

struct f_eem {
	struct gether			port;
	u8				ctrl_id;
};

static inline struct f_eem *func_to_eem(struct usb_function *f)
{
	return container_of(f, struct f_eem, port.func);
}

/*-------------------------------------------------------------------------*/

/* interface descriptor: */

static struct usb_interface_descriptor eem_intf = {
	.bLength =		sizeof eem_intf,
	.bDescriptorType =	USB_DT_INTERFACE,

	/* .bInterfaceNumber = DYNAMIC */
	.bNumEndpoints =	2,
	.bInterfaceClass =	USB_CLASS_COMM,
	.bInterfaceSubClass =	USB_CDC_SUBCLASS_EEM,
	.bInterfaceProtocol =	USB_CDC_PROTO_EEM,
	/* .iInterface = DYNAMIC */
};

/* full speed support: */

static struct usb_endpoint_descriptor eem_fs_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
};

static struct usb_endpoint_descriptor eem_fs_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_OUT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
};

static struct usb_descriptor_header *eem_fs_function[] = {
	/* CDC EEM control descriptors */
	(struct usb_descriptor_header *) &eem_intf,
	(struct usb_descriptor_header *) &eem_fs_in_desc,
	(struct usb_descriptor_header *) &eem_fs_out_desc,
	NULL,
};

/* high speed support: */

static struct usb_endpoint_descriptor eem_hs_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
};

static struct usb_endpoint_descriptor eem_hs_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_OUT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
};

static struct usb_descriptor_header *eem_hs_function[] = {
	/* CDC EEM control descriptors */
	(struct usb_descriptor_header *) &eem_intf,
	(struct usb_descriptor_header *) &eem_hs_in_desc,
	(struct usb_descriptor_header *) &eem_hs_out_desc,
	NULL,
};

/* super speed support: */

static struct usb_endpoint_descriptor eem_ss_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};

static struct usb_endpoint_descriptor eem_ss_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_OUT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};

static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc = {
	.bLength =		sizeof eem_ss_bulk_comp_desc,
	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,

	/* the following 2 values can be tweaked if necessary */
	/* .bMaxBurst =		0, */
	/* .bmAttributes =	0, */
};

static struct usb_descriptor_header *eem_ss_function[] = {
	/* CDC EEM control descriptors */
	(struct usb_descriptor_header *) &eem_intf,
	(struct usb_descriptor_header *) &eem_ss_in_desc,
	(struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
	(struct usb_descriptor_header *) &eem_ss_out_desc,
	(struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
	NULL,
};

/* string descriptors: */

static struct usb_string eem_string_defs[] = {
	[0].s = "CDC Ethernet Emulation Model (EEM)",
	{  } /* end of list */
};

static struct usb_gadget_strings eem_string_table = {
	.language =		0x0409,	/* en-us */
	.strings =		eem_string_defs,
};

static struct usb_gadget_strings *eem_strings[] = {
	&eem_string_table,
	NULL,
};

/*-------------------------------------------------------------------------*/

static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
{
	struct usb_composite_dev *cdev = f->config->cdev;
	int			value = -EOPNOTSUPP;
	u16			w_index = le16_to_cpu(ctrl->wIndex);
	u16			w_value = le16_to_cpu(ctrl->wValue);
	u16			w_length = le16_to_cpu(ctrl->wLength);

	DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
		ctrl->bRequestType, ctrl->bRequest,
		w_value, w_index, w_length);

	/* device either stalls (value < 0) or reports success */
	return value;
}


static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
	struct f_eem		*eem = func_to_eem(f);
	struct usb_composite_dev *cdev = f->config->cdev;
	struct net_device	*net;

	/* we know alt == 0, so this is an activation or a reset */
	if (alt != 0)
		goto fail;

	if (intf == eem->ctrl_id) {
		DBG(cdev, "reset eem\n");
		gether_disconnect(&eem->port);

		if (!eem->port.in_ep->desc || !eem->port.out_ep->desc) {
			DBG(cdev, "init eem\n");
			if (config_ep_by_speed(cdev->gadget, f,
					       eem->port.in_ep) ||
			    config_ep_by_speed(cdev->gadget, f,
					       eem->port.out_ep)) {
				eem->port.in_ep->desc = NULL;
				eem->port.out_ep->desc = NULL;
				goto fail;
			}
		}

		/* zlps should not occur because zero-length EEM packets
		 * will be inserted in those cases where they would occur
		 */
		eem->port.is_zlp_ok = 1;
		eem->port.cdc_filter = DEFAULT_FILTER;
		DBG(cdev, "activate eem\n");
		net = gether_connect(&eem->port);
		if (IS_ERR(net))
			return PTR_ERR(net);
	} else
		goto fail;

	return 0;
fail:
	return -EINVAL;
}

static void eem_disable(struct usb_function *f)
{
	struct f_eem		*eem = func_to_eem(f);
	struct usb_composite_dev *cdev = f->config->cdev;

	DBG(cdev, "eem deactivated\n");

	if (eem->port.in_ep->enabled)
		gether_disconnect(&eem->port);
}

/*-------------------------------------------------------------------------*/

/* EEM function driver setup/binding */

static int eem_bind(struct usb_configuration *c, struct usb_function *f)
{
	struct usb_composite_dev *cdev = c->cdev;
	struct f_eem		*eem = func_to_eem(f);
	struct usb_string	*us;
	int			status;
	struct usb_ep		*ep;

	struct f_eem_opts	*eem_opts;

	eem_opts = container_of(f->fi, struct f_eem_opts, func_inst);
	/*
	 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
	 * configurations are bound in sequence with list_for_each_entry,
	 * in each configuration its functions are bound in sequence
	 * with list_for_each_entry, so we assume no race condition
	 * with regard to eem_opts->bound access
	 */
	if (!eem_opts->bound) {
		mutex_lock(&eem_opts->lock);
		gether_set_gadget(eem_opts->net, cdev->gadget);
		status = gether_register_netdev(eem_opts->net);
		mutex_unlock(&eem_opts->lock);
		if (status)
			return status;
		eem_opts->bound = true;
	}

	us = usb_gstrings_attach(cdev, eem_strings,
				 ARRAY_SIZE(eem_string_defs));
	if (IS_ERR(us))
		return PTR_ERR(us);
	eem_intf.iInterface = us[0].id;

	/* allocate instance-specific interface IDs */
	status = usb_interface_id(c, f);
	if (status < 0)
		goto fail;
	eem->ctrl_id = status;
	eem_intf.bInterfaceNumber = status;

	status = -ENODEV;

	/* allocate instance-specific endpoints */
	ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
	if (!ep)
		goto fail;
	eem->port.in_ep = ep;

	ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
	if (!ep)
		goto fail;
	eem->port.out_ep = ep;

	status = -ENOMEM;

	/* support all relevant hardware speeds... we expect that when
	 * hardware is dual speed, all bulk-capable endpoints work at
	 * both speeds
	 */
	eem_hs_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
	eem_hs_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;

	eem_ss_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
	eem_ss_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;

	status = usb_assign_descriptors(f, eem_fs_function, eem_hs_function,
			eem_ss_function);
	if (status)
		goto fail;

	DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
			gadget_is_superspeed(c->cdev->gadget) ? "super" :
			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
			eem->port.in_ep->name, eem->port.out_ep->name);
	return 0;

fail:
	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);

	return status;
}

static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct sk_buff *skb = (struct sk_buff *)req->context;

	dev_kfree_skb_any(skb);
}

/*
 * Add the EEM header and ethernet checksum.
 * We currently do not attempt to put multiple ethernet frames
 * into a single USB transfer
 */
static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
{
	struct sk_buff	*skb2 = NULL;
	struct usb_ep	*in = port->in_ep;
	int		padlen = 0;
	u16		len = skb->len;

	int headroom = skb_headroom(skb);
	int tailroom = skb_tailroom(skb);

	/* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
	 * stick two bytes of zero-length EEM packet on the end.
	 */
	if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
		padlen += 2;

	if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
			(headroom >= EEM_HLEN) && !skb_cloned(skb))
		goto done;

	skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
	dev_kfree_skb_any(skb);
	skb = skb2;
	if (!skb)
		return skb;

done:
	/* use the "no CRC" option */
	put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));

	/* EEM packet header format:
	 * b0..13:	length of ethernet frame
	 * b14:		bmCRC (0 == sentinel CRC)
	 * b15:		bmType (0 == data)
	 */
	len = skb->len;
	put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));

	/* add a zero-length EEM packet, if needed */
	if (padlen)
		put_unaligned_le16(0, skb_put(skb, 2));

	return skb;
}

/*
 * Remove the EEM header.  Note that there can be many EEM packets in a single
 * USB transfer, so we need to break them out and handle them independently.
 */
static int eem_unwrap(struct gether *port,
			struct sk_buff *skb,
			struct sk_buff_head *list)
{
	struct usb_composite_dev	*cdev = port->func.config->cdev;
	int				status = 0;

	do {
		struct sk_buff	*skb2;
		u16		header;
		u16		len = 0;

		if (skb->len < EEM_HLEN) {
			status = -EINVAL;
			DBG(cdev, "invalid EEM header\n");
			goto error;
		}

		/* remove the EEM header */
		header = get_unaligned_le16(skb->data);
		skb_pull(skb, EEM_HLEN);

		/* EEM packet header format:
		 * b0..14:	EEM type dependent (data or command)
		 * b15:		bmType (0 == data, 1 == command)
		 */
		if (header & BIT(15)) {
			struct usb_request	*req = cdev->req;
			u16			bmEEMCmd;

			/* EEM command packet format:
			 * b0..10:	bmEEMCmdParam
			 * b11..13:	bmEEMCmd
			 * b14:		reserved (must be zero)
			 * b15:		bmType (1 == command)
			 */
			if (header & BIT(14))
				continue;

			bmEEMCmd = (header >> 11) & 0x7;
			switch (bmEEMCmd) {
			case 0: /* echo */
				len = header & 0x7FF;
				if (skb->len < len) {
					status = -EOVERFLOW;
					goto error;
				}

				skb2 = skb_clone(skb, GFP_ATOMIC);
				if (unlikely(!skb2)) {
					DBG(cdev, "EEM echo response error\n");
					goto next;
				}
				skb_trim(skb2, len);
				put_unaligned_le16(BIT(15) | BIT(11) | len,
							skb_push(skb2, 2));
				skb_copy_bits(skb2, 0, req->buf, skb2->len);
				req->length = skb2->len;
				req->complete = eem_cmd_complete;
				req->zero = 1;
				req->context = skb2;
				if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
					DBG(cdev, "echo response queue fail\n");
				break;

			case 1:  /* echo response */
			case 2:  /* suspend hint */
			case 3:  /* response hint */
			case 4:  /* response complete hint */
			case 5:  /* tickle */
			default: /* reserved */
				continue;
			}
		} else {
			u32		crc, crc2;
			struct sk_buff	*skb3;

			/* check for zero-length EEM packet */
			if (header == 0)
				continue;

			/* EEM data packet format:
			 * b0..13:	length of ethernet frame
			 * b14:		bmCRC (0 == sentinel, 1 == calculated)
			 * b15:		bmType (0 == data)
			 */
			len = header & 0x3FFF;
			if ((skb->len < len)
					|| (len < (ETH_HLEN + ETH_FCS_LEN))) {
				status = -EINVAL;
				goto error;
			}

			/* validate CRC */
			if (header & BIT(14)) {
				crc = get_unaligned_le32(skb->data + len
							- ETH_FCS_LEN);
				crc2 = ~crc32_le(~0,
						skb->data, len - ETH_FCS_LEN);
			} else {
				crc = get_unaligned_be32(skb->data + len
							- ETH_FCS_LEN);
				crc2 = 0xdeadbeef;
			}
			if (crc != crc2) {
				DBG(cdev, "invalid EEM CRC\n");
				goto next;
			}

			skb2 = skb_clone(skb, GFP_ATOMIC);
			if (unlikely(!skb2)) {
				DBG(cdev, "unable to unframe EEM packet\n");
				continue;
			}
			skb_trim(skb2, len - ETH_FCS_LEN);

			skb3 = skb_copy_expand(skb2,
						NET_IP_ALIGN,
						0,
						GFP_ATOMIC);
			if (unlikely(!skb3)) {
				DBG(cdev, "unable to realign EEM packet\n");
				dev_kfree_skb_any(skb2);
				continue;
			}
			dev_kfree_skb_any(skb2);
			skb_queue_tail(list, skb3);
		}
next:
		skb_pull(skb, len);
	} while (skb->len);

error:
	dev_kfree_skb_any(skb);
	return status;
}

static inline struct f_eem_opts *to_f_eem_opts(struct config_item *item)
{
	return container_of(to_config_group(item), struct f_eem_opts,
			    func_inst.group);
}

/* f_eem_item_ops */
USB_ETHERNET_CONFIGFS_ITEM(eem);

/* f_eem_opts_dev_addr */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(eem);

/* f_eem_opts_host_addr */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(eem);

/* f_eem_opts_qmult */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(eem);

/* f_eem_opts_ifname */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(eem);

static struct configfs_attribute *eem_attrs[] = {
	&eem_opts_attr_dev_addr,
	&eem_opts_attr_host_addr,
	&eem_opts_attr_qmult,
	&eem_opts_attr_ifname,
	NULL,
};

static struct config_item_type eem_func_type = {
	.ct_item_ops	= &eem_item_ops,
	.ct_attrs	= eem_attrs,
	.ct_owner	= THIS_MODULE,
};

static void eem_free_inst(struct usb_function_instance *f)
{
	struct f_eem_opts *opts;

	opts = container_of(f, struct f_eem_opts, func_inst);
	if (opts->bound)
		gether_cleanup(netdev_priv(opts->net));
	else
		free_netdev(opts->net);
	kfree(opts);
}

static struct usb_function_instance *eem_alloc_inst(void)
{
	struct f_eem_opts *opts;

	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
	if (!opts)
		return ERR_PTR(-ENOMEM);
	mutex_init(&opts->lock);
	opts->func_inst.free_func_inst = eem_free_inst;
	opts->net = gether_setup_default();
	if (IS_ERR(opts->net)) {
		struct net_device *net = opts->net;
		kfree(opts);
		return ERR_CAST(net);
	}

	config_group_init_type_name(&opts->func_inst.group, "", &eem_func_type);

	return &opts->func_inst;
}

static void eem_free(struct usb_function *f)
{
	struct f_eem *eem;
	struct f_eem_opts *opts;

	eem = func_to_eem(f);
	opts = container_of(f->fi, struct f_eem_opts, func_inst);
	kfree(eem);
	mutex_lock(&opts->lock);
	opts->refcnt--;
	mutex_unlock(&opts->lock);
}

static void eem_unbind(struct usb_configuration *c, struct usb_function *f)
{
	DBG(c->cdev, "eem unbind\n");

	usb_free_all_descriptors(f);
}

static struct usb_function *eem_alloc(struct usb_function_instance *fi)
{
	struct f_eem	*eem;
	struct f_eem_opts *opts;

	/* allocate and initialize one new instance */
	eem = kzalloc(sizeof(*eem), GFP_KERNEL);
	if (!eem)
		return ERR_PTR(-ENOMEM);

	opts = container_of(fi, struct f_eem_opts, func_inst);
	mutex_lock(&opts->lock);
	opts->refcnt++;

	eem->port.ioport = netdev_priv(opts->net);
	mutex_unlock(&opts->lock);
	eem->port.cdc_filter = DEFAULT_FILTER;

	eem->port.func.name = "cdc_eem";
	/* descriptors are per-instance copies */
	eem->port.func.bind = eem_bind;
	eem->port.func.unbind = eem_unbind;
	eem->port.func.set_alt = eem_set_alt;
	eem->port.func.setup = eem_setup;
	eem->port.func.disable = eem_disable;
	eem->port.func.free_func = eem_free;
	eem->port.wrap = eem_wrap;
	eem->port.unwrap = eem_unwrap;
	eem->port.header_len = EEM_HLEN;

	return &eem->port.func;
}

DECLARE_USB_FUNCTION_INIT(eem, eem_alloc_inst, eem_alloc);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Brownell");