summaryrefslogtreecommitdiff
path: root/drivers/usb/gadget/function/f_ecm.c
blob: d2a83dd78cb968da939f9a279ebe92a66b1bd18a (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
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
// SPDX-License-Identifier: GPL-2.0+
/*
 * f_ecm.c -- USB CDC Ethernet (ECM) link function driver
 *
 * Copyright (C) 2003-2005,2008 David Brownell
 * Copyright (C) 2008 Nokia Corporation
 *
 * 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.
 */

/* #define VERBOSE_DEBUG */

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

#include "u_ether.h"
#include "u_ether_configfs.h"
#include "u_ecm.h"


/*
 * This function is a "CDC Ethernet Networking Control Model" (CDC ECM)
 * Ethernet link.  The data transfer model is simple (packets sent and
 * received over bulk endpoints using normal short packet termination),
 * and the control model exposes various data and optional notifications.
 *
 * ECM is well standardized and (except for Microsoft) supported by most
 * operating systems with USB host support.  It's the preferred interop
 * solution for Ethernet over USB, at least for firmware based solutions.
 * (Hardware solutions tend to be more minimalist.)  A newer and simpler
 * "Ethernet Emulation Model" (CDC EEM) hasn't yet caught on.
 *
 * Note that ECM requires the use of "alternate settings" for its data
 * interface.  This means that the set_alt() method has real work to do,
 * and also means that a get_alt() method is required.
 */


enum ecm_notify_state {
	ECM_NOTIFY_NONE,		/* don't notify */
	ECM_NOTIFY_CONNECT,		/* issue CONNECT next */
	ECM_NOTIFY_SPEED,		/* issue SPEED_CHANGE next */
};

struct f_ecm {
	struct gether			port;
	u8				ctrl_id, data_id;

	char				ethaddr[14];

	struct usb_ep			*notify;
	struct usb_request		*notify_req;
	u8				notify_state;
	bool				is_open;

	/* FIXME is_open needs some irq-ish locking
	 * ... possibly the same as port.ioport
	 */
};

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

/* peak (theoretical) bulk transfer rate in bits-per-second */
static inline unsigned ecm_bitrate(struct usb_gadget *g)
{
	if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
		return 13 * 1024 * 8 * 1000 * 8;
	else if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
		return 13 * 512 * 8 * 1000 * 8;
	else
		return 19 * 64 * 1 * 1000 * 8;
}

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

/*
 * Include the status endpoint if we can, even though it's optional.
 *
 * Use wMaxPacketSize big enough to fit CDC_NOTIFY_SPEED_CHANGE in one
 * packet, to simplify cancellation; and a big transfer interval, to
 * waste less bandwidth.
 *
 * Some drivers (like Linux 2.4 cdc-ether!) "need" it to exist even
 * if they ignore the connect/disconnect notifications that real aether
 * can provide.  More advanced cdc configurations might want to support
 * encapsulated commands (vendor-specific, using control-OUT).
 */

#define ECM_STATUS_INTERVAL_MS		32
#define ECM_STATUS_BYTECOUNT		16	/* 8 byte header + data */


/* interface descriptor: */

static struct usb_interface_assoc_descriptor
ecm_iad_descriptor = {
	.bLength =		sizeof ecm_iad_descriptor,
	.bDescriptorType =	USB_DT_INTERFACE_ASSOCIATION,

	/* .bFirstInterface =	DYNAMIC, */
	.bInterfaceCount =	2,	/* control + data */
	.bFunctionClass =	USB_CLASS_COMM,
	.bFunctionSubClass =	USB_CDC_SUBCLASS_ETHERNET,
	.bFunctionProtocol =	USB_CDC_PROTO_NONE,
	/* .iFunction =		DYNAMIC */
};


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

	/* .bInterfaceNumber = DYNAMIC */
	/* status endpoint is optional; this could be patched later */
	.bNumEndpoints =	1,
	.bInterfaceClass =	USB_CLASS_COMM,
	.bInterfaceSubClass =	USB_CDC_SUBCLASS_ETHERNET,
	.bInterfaceProtocol =	USB_CDC_PROTO_NONE,
	/* .iInterface = DYNAMIC */
};

static struct usb_cdc_header_desc ecm_header_desc = {
	.bLength =		sizeof ecm_header_desc,
	.bDescriptorType =	USB_DT_CS_INTERFACE,
	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,

	.bcdCDC =		cpu_to_le16(0x0110),
};

static struct usb_cdc_union_desc ecm_union_desc = {
	.bLength =		sizeof(ecm_union_desc),
	.bDescriptorType =	USB_DT_CS_INTERFACE,
	.bDescriptorSubType =	USB_CDC_UNION_TYPE,
	/* .bMasterInterface0 =	DYNAMIC */
	/* .bSlaveInterface0 =	DYNAMIC */
};

static struct usb_cdc_ether_desc ecm_desc = {
	.bLength =		sizeof ecm_desc,
	.bDescriptorType =	USB_DT_CS_INTERFACE,
	.bDescriptorSubType =	USB_CDC_ETHERNET_TYPE,

	/* this descriptor actually adds value, surprise! */
	/* .iMACAddress = DYNAMIC */
	.bmEthernetStatistics =	cpu_to_le32(0), /* no statistics */
	.wMaxSegmentSize =	cpu_to_le16(ETH_FRAME_LEN),
	.wNumberMCFilters =	cpu_to_le16(0),
	.bNumberPowerFilters =	0,
};

/* the default data interface has no endpoints ... */

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

	.bInterfaceNumber =	1,
	.bAlternateSetting =	0,
	.bNumEndpoints =	0,
	.bInterfaceClass =	USB_CLASS_CDC_DATA,
	.bInterfaceSubClass =	0,
	.bInterfaceProtocol =	0,
	/* .iInterface = DYNAMIC */
};

/* ... but the "real" data interface has two bulk endpoints */

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

	.bInterfaceNumber =	1,
	.bAlternateSetting =	1,
	.bNumEndpoints =	2,
	.bInterfaceClass =	USB_CLASS_CDC_DATA,
	.bInterfaceSubClass =	0,
	.bInterfaceProtocol =	0,
	/* .iInterface = DYNAMIC */
};

/* full speed support: */

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

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_INT,
	.wMaxPacketSize =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
	.bInterval =		ECM_STATUS_INTERVAL_MS,
};

static struct usb_endpoint_descriptor fs_ecm_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 fs_ecm_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 *ecm_fs_function[] = {
	/* CDC ECM control descriptors */
	(struct usb_descriptor_header *) &ecm_iad_descriptor,
	(struct usb_descriptor_header *) &ecm_control_intf,
	(struct usb_descriptor_header *) &ecm_header_desc,
	(struct usb_descriptor_header *) &ecm_union_desc,
	(struct usb_descriptor_header *) &ecm_desc,

	/* NOTE: status endpoint might need to be removed */
	(struct usb_descriptor_header *) &fs_ecm_notify_desc,

	/* data interface, altsettings 0 and 1 */
	(struct usb_descriptor_header *) &ecm_data_nop_intf,
	(struct usb_descriptor_header *) &ecm_data_intf,
	(struct usb_descriptor_header *) &fs_ecm_in_desc,
	(struct usb_descriptor_header *) &fs_ecm_out_desc,
	NULL,
};

/* high speed support: */

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

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_INT,
	.wMaxPacketSize =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
	.bInterval =		USB_MS_TO_HS_INTERVAL(ECM_STATUS_INTERVAL_MS),
};

static struct usb_endpoint_descriptor hs_ecm_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 hs_ecm_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 *ecm_hs_function[] = {
	/* CDC ECM control descriptors */
	(struct usb_descriptor_header *) &ecm_iad_descriptor,
	(struct usb_descriptor_header *) &ecm_control_intf,
	(struct usb_descriptor_header *) &ecm_header_desc,
	(struct usb_descriptor_header *) &ecm_union_desc,
	(struct usb_descriptor_header *) &ecm_desc,

	/* NOTE: status endpoint might need to be removed */
	(struct usb_descriptor_header *) &hs_ecm_notify_desc,

	/* data interface, altsettings 0 and 1 */
	(struct usb_descriptor_header *) &ecm_data_nop_intf,
	(struct usb_descriptor_header *) &ecm_data_intf,
	(struct usb_descriptor_header *) &hs_ecm_in_desc,
	(struct usb_descriptor_header *) &hs_ecm_out_desc,
	NULL,
};

/* super speed support: */

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

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_INT,
	.wMaxPacketSize =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
	.bInterval =		USB_MS_TO_HS_INTERVAL(ECM_STATUS_INTERVAL_MS),
};

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

	/* the following 3 values can be tweaked if necessary */
	/* .bMaxBurst =		0, */
	/* .bmAttributes =	0, */
	.wBytesPerInterval =	cpu_to_le16(ECM_STATUS_BYTECOUNT),
};

static struct usb_endpoint_descriptor ss_ecm_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 ss_ecm_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 ss_ecm_bulk_comp_desc = {
	.bLength =		sizeof ss_ecm_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 *ecm_ss_function[] = {
	/* CDC ECM control descriptors */
	(struct usb_descriptor_header *) &ecm_iad_descriptor,
	(struct usb_descriptor_header *) &ecm_control_intf,
	(struct usb_descriptor_header *) &ecm_header_desc,
	(struct usb_descriptor_header *) &ecm_union_desc,
	(struct usb_descriptor_header *) &ecm_desc,

	/* NOTE: status endpoint might need to be removed */
	(struct usb_descriptor_header *) &ss_ecm_notify_desc,
	(struct usb_descriptor_header *) &ss_ecm_intr_comp_desc,

	/* data interface, altsettings 0 and 1 */
	(struct usb_descriptor_header *) &ecm_data_nop_intf,
	(struct usb_descriptor_header *) &ecm_data_intf,
	(struct usb_descriptor_header *) &ss_ecm_in_desc,
	(struct usb_descriptor_header *) &ss_ecm_bulk_comp_desc,
	(struct usb_descriptor_header *) &ss_ecm_out_desc,
	(struct usb_descriptor_header *) &ss_ecm_bulk_comp_desc,
	NULL,
};

/* string descriptors: */

static struct usb_string ecm_string_defs[] = {
	[0].s = "CDC Ethernet Control Model (ECM)",
	[1].s = "",
	[2].s = "CDC Ethernet Data",
	[3].s = "CDC ECM",
	{  } /* end of list */
};

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

static struct usb_gadget_strings *ecm_strings[] = {
	&ecm_string_table,
	NULL,
};

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

static void ecm_do_notify(struct f_ecm *ecm)
{
	struct usb_request		*req = ecm->notify_req;
	struct usb_cdc_notification	*event;
	struct usb_composite_dev	*cdev = ecm->port.func.config->cdev;
	__le32				*data;
	int				status;

	/* notification already in flight? */
	if (!req)
		return;

	event = req->buf;
	switch (ecm->notify_state) {
	case ECM_NOTIFY_NONE:
		return;

	case ECM_NOTIFY_CONNECT:
		event->bNotificationType = USB_CDC_NOTIFY_NETWORK_CONNECTION;
		if (ecm->is_open)
			event->wValue = cpu_to_le16(1);
		else
			event->wValue = cpu_to_le16(0);
		event->wLength = 0;
		req->length = sizeof *event;

		DBG(cdev, "notify connect %s\n",
				ecm->is_open ? "true" : "false");
		ecm->notify_state = ECM_NOTIFY_SPEED;
		break;

	case ECM_NOTIFY_SPEED:
		event->bNotificationType = USB_CDC_NOTIFY_SPEED_CHANGE;
		event->wValue = cpu_to_le16(0);
		event->wLength = cpu_to_le16(8);
		req->length = ECM_STATUS_BYTECOUNT;

		/* SPEED_CHANGE data is up/down speeds in bits/sec */
		data = req->buf + sizeof *event;
		data[0] = cpu_to_le32(ecm_bitrate(cdev->gadget));
		data[1] = data[0];

		DBG(cdev, "notify speed %d\n", ecm_bitrate(cdev->gadget));
		ecm->notify_state = ECM_NOTIFY_NONE;
		break;
	}
	event->bmRequestType = 0xA1;
	event->wIndex = cpu_to_le16(ecm->ctrl_id);

	ecm->notify_req = NULL;
	status = usb_ep_queue(ecm->notify, req, GFP_ATOMIC);
	if (status < 0) {
		ecm->notify_req = req;
		DBG(cdev, "notify --> %d\n", status);
	}
}

static void ecm_notify(struct f_ecm *ecm)
{
	/* NOTE on most versions of Linux, host side cdc-ethernet
	 * won't listen for notifications until its netdevice opens.
	 * The first notification then sits in the FIFO for a long
	 * time, and the second one is queued.
	 */
	ecm->notify_state = ECM_NOTIFY_CONNECT;
	ecm_do_notify(ecm);
}

static void ecm_notify_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct f_ecm			*ecm = req->context;
	struct usb_composite_dev	*cdev = ecm->port.func.config->cdev;
	struct usb_cdc_notification	*event = req->buf;

	switch (req->status) {
	case 0:
		/* no fault */
		break;
	case -ECONNRESET:
	case -ESHUTDOWN:
		ecm->notify_state = ECM_NOTIFY_NONE;
		break;
	default:
		DBG(cdev, "event %02x --> %d\n",
			event->bNotificationType, req->status);
		break;
	}
	ecm->notify_req = req;
	ecm_do_notify(ecm);
}

static int ecm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
{
	struct f_ecm		*ecm = func_to_ecm(f);
	struct usb_composite_dev *cdev = f->config->cdev;
	struct usb_request	*req = cdev->req;
	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);

	/* composite driver infrastructure handles everything except
	 * CDC class messages; interface activation uses set_alt().
	 */
	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
			| USB_CDC_SET_ETHERNET_PACKET_FILTER:
		/* see 6.2.30: no data, wIndex = interface,
		 * wValue = packet filter bitmap
		 */
		if (w_length != 0 || w_index != ecm->ctrl_id)
			goto invalid;
		DBG(cdev, "packet filter %02x\n", w_value);
		/* REVISIT locking of cdc_filter.  This assumes the UDC
		 * driver won't have a concurrent packet TX irq running on
		 * another CPU; or that if it does, this write is atomic...
		 */
		ecm->port.cdc_filter = w_value;
		value = 0;
		break;

	/* and optionally:
	 * case USB_CDC_SEND_ENCAPSULATED_COMMAND:
	 * case USB_CDC_GET_ENCAPSULATED_RESPONSE:
	 * case USB_CDC_SET_ETHERNET_MULTICAST_FILTERS:
	 * case USB_CDC_SET_ETHERNET_PM_PATTERN_FILTER:
	 * case USB_CDC_GET_ETHERNET_PM_PATTERN_FILTER:
	 * case USB_CDC_GET_ETHERNET_STATISTIC:
	 */

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

	/* respond with data transfer or status phase? */
	if (value >= 0) {
		DBG(cdev, "ecm req%02x.%02x v%04x i%04x l%d\n",
			ctrl->bRequestType, ctrl->bRequest,
			w_value, w_index, w_length);
		req->zero = 0;
		req->length = value;
		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
		if (value < 0)
			ERROR(cdev, "ecm req %02x.%02x response err %d\n",
					ctrl->bRequestType, ctrl->bRequest,
					value);
	}

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


static int ecm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
	struct f_ecm		*ecm = func_to_ecm(f);
	struct usb_composite_dev *cdev = f->config->cdev;

	/* Control interface has only altsetting 0 */
	if (intf == ecm->ctrl_id) {
		if (alt != 0)
			goto fail;

		VDBG(cdev, "reset ecm control %d\n", intf);
		usb_ep_disable(ecm->notify);
		if (!(ecm->notify->desc)) {
			VDBG(cdev, "init ecm ctrl %d\n", intf);
			if (config_ep_by_speed(cdev->gadget, f, ecm->notify))
				goto fail;
		}
		usb_ep_enable(ecm->notify);

	/* Data interface has two altsettings, 0 and 1 */
	} else if (intf == ecm->data_id) {
		if (alt > 1)
			goto fail;

		if (ecm->port.in_ep->enabled) {
			DBG(cdev, "reset ecm\n");
			gether_disconnect(&ecm->port);
		}

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

		/* CDC Ethernet only sends data in non-default altsettings.
		 * Changing altsettings resets filters, statistics, etc.
		 */
		if (alt == 1) {
			struct net_device	*net;

			/* Enable zlps by default for ECM conformance;
			 * override for musb_hdrc (avoids txdma ovhead).
			 */
			ecm->port.is_zlp_ok =
				gadget_is_zlp_supported(cdev->gadget);
			ecm->port.cdc_filter = DEFAULT_FILTER;
			DBG(cdev, "activate ecm\n");
			net = gether_connect(&ecm->port);
			if (IS_ERR(net))
				return PTR_ERR(net);
		}

		/* NOTE this can be a minor disagreement with the ECM spec,
		 * which says speed notifications will "always" follow
		 * connection notifications.  But we allow one connect to
		 * follow another (if the first is in flight), and instead
		 * just guarantee that a speed notification is always sent.
		 */
		ecm_notify(ecm);
	} else
		goto fail;

	return 0;
fail:
	return -EINVAL;
}

/* Because the data interface supports multiple altsettings,
 * this ECM function *MUST* implement a get_alt() method.
 */
static int ecm_get_alt(struct usb_function *f, unsigned intf)
{
	struct f_ecm		*ecm = func_to_ecm(f);

	if (intf == ecm->ctrl_id)
		return 0;
	return ecm->port.in_ep->enabled ? 1 : 0;
}

static void ecm_disable(struct usb_function *f)
{
	struct f_ecm		*ecm = func_to_ecm(f);
	struct usb_composite_dev *cdev = f->config->cdev;

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

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

	usb_ep_disable(ecm->notify);
	ecm->notify->desc = NULL;
}

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

/*
 * Callbacks let us notify the host about connect/disconnect when the
 * net device is opened or closed.
 *
 * For testing, note that link states on this side include both opened
 * and closed variants of:
 *
 *   - disconnected/unconfigured
 *   - configured but inactive (data alt 0)
 *   - configured and active (data alt 1)
 *
 * Each needs to be tested with unplug, rmmod, SET_CONFIGURATION, and
 * SET_INTERFACE (altsetting).  Remember also that "configured" doesn't
 * imply the host is actually polling the notification endpoint, and
 * likewise that "active" doesn't imply it's actually using the data
 * endpoints for traffic.
 */

static void ecm_open(struct gether *geth)
{
	struct f_ecm		*ecm = func_to_ecm(&geth->func);

	DBG(ecm->port.func.config->cdev, "%s\n", __func__);

	ecm->is_open = true;
	ecm_notify(ecm);
}

static void ecm_close(struct gether *geth)
{
	struct f_ecm		*ecm = func_to_ecm(&geth->func);

	DBG(ecm->port.func.config->cdev, "%s\n", __func__);

	ecm->is_open = false;
	ecm_notify(ecm);
}

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

/* ethernet function driver setup/binding */

static int
ecm_bind(struct usb_configuration *c, struct usb_function *f)
{
	struct usb_composite_dev *cdev = c->cdev;
	struct f_ecm		*ecm = func_to_ecm(f);
	struct usb_string	*us;
	int			status;
	struct usb_ep		*ep;

	struct f_ecm_opts	*ecm_opts;

	if (!can_support_ecm(cdev->gadget))
		return -EINVAL;

	ecm_opts = container_of(f->fi, struct f_ecm_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 ecm_opts->bound access
	 */
	if (!ecm_opts->bound) {
		mutex_lock(&ecm_opts->lock);
		gether_set_gadget(ecm_opts->net, cdev->gadget);
		status = gether_register_netdev(ecm_opts->net);
		mutex_unlock(&ecm_opts->lock);
		if (status)
			return status;
		ecm_opts->bound = true;
	}

	us = usb_gstrings_attach(cdev, ecm_strings,
				 ARRAY_SIZE(ecm_string_defs));
	if (IS_ERR(us))
		return PTR_ERR(us);
	ecm_control_intf.iInterface = us[0].id;
	ecm_data_intf.iInterface = us[2].id;
	ecm_desc.iMACAddress = us[1].id;
	ecm_iad_descriptor.iFunction = us[3].id;

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

	ecm_control_intf.bInterfaceNumber = status;
	ecm_union_desc.bMasterInterface0 = status;

	status = usb_interface_id(c, f);
	if (status < 0)
		goto fail;
	ecm->data_id = status;

	ecm_data_nop_intf.bInterfaceNumber = status;
	ecm_data_intf.bInterfaceNumber = status;
	ecm_union_desc.bSlaveInterface0 = status;

	status = -ENODEV;

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

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

	/* NOTE:  a status/notification endpoint is *OPTIONAL* but we
	 * don't treat it that way.  It's simpler, and some newer CDC
	 * profiles (wireless handsets) no longer treat it as optional.
	 */
	ep = usb_ep_autoconfig(cdev->gadget, &fs_ecm_notify_desc);
	if (!ep)
		goto fail;
	ecm->notify = ep;

	status = -ENOMEM;

	/* allocate notification request and buffer */
	ecm->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
	if (!ecm->notify_req)
		goto fail;
	ecm->notify_req->buf = kmalloc(ECM_STATUS_BYTECOUNT, GFP_KERNEL);
	if (!ecm->notify_req->buf)
		goto fail;
	ecm->notify_req->context = ecm;
	ecm->notify_req->complete = ecm_notify_complete;

	/* support all relevant hardware speeds... we expect that when
	 * hardware is dual speed, all bulk-capable endpoints work at
	 * both speeds
	 */
	hs_ecm_in_desc.bEndpointAddress = fs_ecm_in_desc.bEndpointAddress;
	hs_ecm_out_desc.bEndpointAddress = fs_ecm_out_desc.bEndpointAddress;
	hs_ecm_notify_desc.bEndpointAddress =
		fs_ecm_notify_desc.bEndpointAddress;

	ss_ecm_in_desc.bEndpointAddress = fs_ecm_in_desc.bEndpointAddress;
	ss_ecm_out_desc.bEndpointAddress = fs_ecm_out_desc.bEndpointAddress;
	ss_ecm_notify_desc.bEndpointAddress =
		fs_ecm_notify_desc.bEndpointAddress;

	status = usb_assign_descriptors(f, ecm_fs_function, ecm_hs_function,
			ecm_ss_function, NULL);
	if (status)
		goto fail;

	/* NOTE:  all that is done without knowing or caring about
	 * the network link ... which is unavailable to this code
	 * until we're activated via set_alt().
	 */

	ecm->port.open = ecm_open;
	ecm->port.close = ecm_close;

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

fail:
	if (ecm->notify_req) {
		kfree(ecm->notify_req->buf);
		usb_ep_free_request(ecm->notify, ecm->notify_req);
	}

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

	return status;
}

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

/* f_ecm_item_ops */
USB_ETHERNET_CONFIGFS_ITEM(ecm);

/* f_ecm_opts_dev_addr */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(ecm);

/* f_ecm_opts_host_addr */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(ecm);

/* f_ecm_opts_qmult */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(ecm);

/* f_ecm_opts_ifname */
USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(ecm);

static struct configfs_attribute *ecm_attrs[] = {
	&ecm_opts_attr_dev_addr,
	&ecm_opts_attr_host_addr,
	&ecm_opts_attr_qmult,
	&ecm_opts_attr_ifname,
	NULL,
};

static struct config_item_type ecm_func_type = {
	.ct_item_ops	= &ecm_item_ops,
	.ct_attrs	= ecm_attrs,
	.ct_owner	= THIS_MODULE,
};

static void ecm_free_inst(struct usb_function_instance *f)
{
	struct f_ecm_opts *opts;

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

static struct usb_function_instance *ecm_alloc_inst(void)
{
	struct f_ecm_opts *opts;

	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
	if (!opts)
		return ERR_PTR(-ENOMEM);
	mutex_init(&opts->lock);
	opts->func_inst.free_func_inst = ecm_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, "", &ecm_func_type);

	return &opts->func_inst;
}

static void ecm_free(struct usb_function *f)
{
	struct f_ecm *ecm;
	struct f_ecm_opts *opts;

	ecm = func_to_ecm(f);
	opts = container_of(f->fi, struct f_ecm_opts, func_inst);
	kfree(ecm);
	mutex_lock(&opts->lock);
	opts->refcnt--;
	mutex_unlock(&opts->lock);
}

static void ecm_unbind(struct usb_configuration *c, struct usb_function *f)
{
	struct f_ecm		*ecm = func_to_ecm(f);

	DBG(c->cdev, "ecm unbind\n");

	usb_free_all_descriptors(f);

	kfree(ecm->notify_req->buf);
	usb_ep_free_request(ecm->notify, ecm->notify_req);
}

static struct usb_function *ecm_alloc(struct usb_function_instance *fi)
{
	struct f_ecm	*ecm;
	struct f_ecm_opts *opts;
	int status;

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

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

	/* export host's Ethernet address in CDC format */
	status = gether_get_host_addr_cdc(opts->net, ecm->ethaddr,
					  sizeof(ecm->ethaddr));
	if (status < 12) {
		kfree(ecm);
		mutex_unlock(&opts->lock);
		return ERR_PTR(-EINVAL);
	}
	ecm_string_defs[1].s = ecm->ethaddr;

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

	ecm->port.func.name = "cdc_ethernet";
	/* descriptors are per-instance copies */
	ecm->port.func.bind = ecm_bind;
	ecm->port.func.unbind = ecm_unbind;
	ecm->port.func.set_alt = ecm_set_alt;
	ecm->port.func.get_alt = ecm_get_alt;
	ecm->port.func.setup = ecm_setup;
	ecm->port.func.disable = ecm_disable;
	ecm->port.func.free_func = ecm_free;

	return &ecm->port.func;
}

DECLARE_USB_FUNCTION_INIT(ecm, ecm_alloc_inst, ecm_alloc);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Brownell");