aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/usb/cdc_ncm.c
blob: 4b9513fcf27539953704630475f7754b5e3a7eb4 (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
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
/*
 * cdc_ncm.c
 *
 * Copyright (C) ST-Ericsson 2010-2012
 * Contact: Alexey Orishko <alexey.orishko@stericsson.com>
 * Original author: Hans Petter Selasky <hans.petter.selasky@stericsson.com>
 *
 * USB Host Driver for Network Control Model (NCM)
 * http://www.usb.org/developers/devclass_docs/NCM10.zip
 *
 * The NCM encoding, decoding and initialization logic
 * derives from FreeBSD 8.x. if_cdce.c and if_cdcereg.h
 *
 * This software is available to you under a choice of one of two
 * licenses. You may choose this file to be licensed under the terms
 * of the GNU General Public License (GPL) Version 2 or the 2-clause
 * BSD license listed below:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/ctype.h>
#include <linux/ethtool.h>
#include <linux/workqueue.h>
#include <linux/mii.h>
#include <linux/crc32.h>
#include <linux/usb.h>
#include <linux/hrtimer.h>
#include <linux/atomic.h>
#include <linux/usb/usbnet.h>
#include <linux/usb/cdc.h>

#define	DRIVER_VERSION				"14-Mar-2012"

/* CDC NCM subclass 3.2.1 */
#define USB_CDC_NCM_NDP16_LENGTH_MIN		0x10

/* Maximum NTB length */
#define	CDC_NCM_NTB_MAX_SIZE_TX			32768	/* bytes */
#define	CDC_NCM_NTB_MAX_SIZE_RX			32768	/* bytes */

/* Minimum value for MaxDatagramSize, ch. 6.2.9 */
#define	CDC_NCM_MIN_DATAGRAM_SIZE		1514	/* bytes */

#define	CDC_NCM_MIN_TX_PKT			512	/* bytes */

/* Default value for MaxDatagramSize */
#define	CDC_NCM_MAX_DATAGRAM_SIZE		8192	/* bytes */

/*
 * Maximum amount of datagrams in NCM Datagram Pointer Table, not counting
 * the last NULL entry.
 */
#define	CDC_NCM_DPT_DATAGRAMS_MAX		40

/* Restart the timer, if amount of datagrams is less than given value */
#define	CDC_NCM_RESTART_TIMER_DATAGRAM_CNT	3
#define	CDC_NCM_TIMER_PENDING_CNT		2
#define CDC_NCM_TIMER_INTERVAL			(400UL * NSEC_PER_USEC)

/* The following macro defines the minimum header space */
#define	CDC_NCM_MIN_HDR_SIZE \
	(sizeof(struct usb_cdc_ncm_nth16) + sizeof(struct usb_cdc_ncm_ndp16) + \
	(CDC_NCM_DPT_DATAGRAMS_MAX + 1) * sizeof(struct usb_cdc_ncm_dpe16))

struct cdc_ncm_data {
	struct usb_cdc_ncm_nth16 nth16;
	struct usb_cdc_ncm_ndp16 ndp16;
	struct usb_cdc_ncm_dpe16 dpe16[CDC_NCM_DPT_DATAGRAMS_MAX + 1];
};

struct cdc_ncm_ctx {
	struct cdc_ncm_data tx_ncm;
	struct usb_cdc_ncm_ntb_parameters ncm_parm;
	struct hrtimer tx_timer;
	struct tasklet_struct bh;

	const struct usb_cdc_ncm_desc *func_desc;
	const struct usb_cdc_header_desc *header_desc;
	const struct usb_cdc_union_desc *union_desc;
	const struct usb_cdc_ether_desc *ether_desc;

	struct net_device *netdev;
	struct usb_device *udev;
	struct usb_host_endpoint *in_ep;
	struct usb_host_endpoint *out_ep;
	struct usb_host_endpoint *status_ep;
	struct usb_interface *intf;
	struct usb_interface *control;
	struct usb_interface *data;

	struct sk_buff *tx_curr_skb;
	struct sk_buff *tx_rem_skb;

	spinlock_t mtx;
	atomic_t stop;

	u32 tx_timer_pending;
	u32 tx_curr_offset;
	u32 tx_curr_last_offset;
	u32 tx_curr_frame_num;
	u32 rx_speed;
	u32 tx_speed;
	u32 rx_max;
	u32 tx_max;
	u32 max_datagram_size;
	u16 tx_max_datagrams;
	u16 tx_remainder;
	u16 tx_modulus;
	u16 tx_ndp_modulus;
	u16 tx_seq;
	u16 rx_seq;
	u16 connected;
};

static void cdc_ncm_txpath_bh(unsigned long param);
static void cdc_ncm_tx_timeout_start(struct cdc_ncm_ctx *ctx);
static enum hrtimer_restart cdc_ncm_tx_timer_cb(struct hrtimer *hr_timer);
static const struct driver_info cdc_ncm_info;
static struct usb_driver cdc_ncm_driver;
static const struct ethtool_ops cdc_ncm_ethtool_ops;

static const struct usb_device_id cdc_devs[] = {
	{ USB_INTERFACE_INFO(USB_CLASS_COMM,
		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
		.driver_info = (unsigned long)&cdc_ncm_info,
	},
	{
	},
};

MODULE_DEVICE_TABLE(usb, cdc_devs);

static void
cdc_ncm_get_drvinfo(struct net_device *net, struct ethtool_drvinfo *info)
{
	struct usbnet *dev = netdev_priv(net);

	strncpy(info->driver, dev->driver_name, sizeof(info->driver));
	strncpy(info->version, DRIVER_VERSION, sizeof(info->version));
	strncpy(info->fw_version, dev->driver_info->description,
		sizeof(info->fw_version));
	usb_make_path(dev->udev, info->bus_info, sizeof(info->bus_info));
}

static u8 cdc_ncm_setup(struct cdc_ncm_ctx *ctx)
{
	u32 val;
	u8 flags;
	u8 iface_no;
	int err;
	u16 ntb_fmt_supported;

	iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;

	err = usb_control_msg(ctx->udev,
				usb_rcvctrlpipe(ctx->udev, 0),
				USB_CDC_GET_NTB_PARAMETERS,
				USB_TYPE_CLASS | USB_DIR_IN
				 | USB_RECIP_INTERFACE,
				0, iface_no, &ctx->ncm_parm,
				sizeof(ctx->ncm_parm), 10000);
	if (err < 0) {
		pr_debug("failed GET_NTB_PARAMETERS\n");
		return 1;
	}

	/* read correct set of parameters according to device mode */
	ctx->rx_max = le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize);
	ctx->tx_max = le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize);
	ctx->tx_remainder = le16_to_cpu(ctx->ncm_parm.wNdpOutPayloadRemainder);
	ctx->tx_modulus = le16_to_cpu(ctx->ncm_parm.wNdpOutDivisor);
	ctx->tx_ndp_modulus = le16_to_cpu(ctx->ncm_parm.wNdpOutAlignment);
	/* devices prior to NCM Errata shall set this field to zero */
	ctx->tx_max_datagrams = le16_to_cpu(ctx->ncm_parm.wNtbOutMaxDatagrams);
	ntb_fmt_supported = le16_to_cpu(ctx->ncm_parm.bmNtbFormatsSupported);

	if (ctx->func_desc != NULL)
		flags = ctx->func_desc->bmNetworkCapabilities;
	else
		flags = 0;

	pr_debug("dwNtbInMaxSize=%u dwNtbOutMaxSize=%u "
		 "wNdpOutPayloadRemainder=%u wNdpOutDivisor=%u "
		 "wNdpOutAlignment=%u wNtbOutMaxDatagrams=%u flags=0x%x\n",
		 ctx->rx_max, ctx->tx_max, ctx->tx_remainder, ctx->tx_modulus,
		 ctx->tx_ndp_modulus, ctx->tx_max_datagrams, flags);

	/* max count of tx datagrams */
	if ((ctx->tx_max_datagrams == 0) ||
			(ctx->tx_max_datagrams > CDC_NCM_DPT_DATAGRAMS_MAX))
		ctx->tx_max_datagrams = CDC_NCM_DPT_DATAGRAMS_MAX;

	/* verify maximum size of received NTB in bytes */
	if (ctx->rx_max < USB_CDC_NCM_NTB_MIN_IN_SIZE) {
		pr_debug("Using min receive length=%d\n",
						USB_CDC_NCM_NTB_MIN_IN_SIZE);
		ctx->rx_max = USB_CDC_NCM_NTB_MIN_IN_SIZE;
	}

	if (ctx->rx_max > CDC_NCM_NTB_MAX_SIZE_RX) {
		pr_debug("Using default maximum receive length=%d\n",
						CDC_NCM_NTB_MAX_SIZE_RX);
		ctx->rx_max = CDC_NCM_NTB_MAX_SIZE_RX;
	}

	/* inform device about NTB input size changes */
	if (ctx->rx_max != le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize)) {

		if (flags & USB_CDC_NCM_NCAP_NTB_INPUT_SIZE) {
			struct usb_cdc_ncm_ndp_input_size *ndp_in_sz;

			ndp_in_sz = kzalloc(sizeof(*ndp_in_sz), GFP_KERNEL);
			if (!ndp_in_sz) {
				err = -ENOMEM;
				goto size_err;
			}

			err = usb_control_msg(ctx->udev,
					usb_sndctrlpipe(ctx->udev, 0),
					USB_CDC_SET_NTB_INPUT_SIZE,
					USB_TYPE_CLASS | USB_DIR_OUT
					 | USB_RECIP_INTERFACE,
					0, iface_no, ndp_in_sz, 8, 1000);
			kfree(ndp_in_sz);
		} else {
			__le32 *dwNtbInMaxSize;
			dwNtbInMaxSize = kzalloc(sizeof(*dwNtbInMaxSize),
					GFP_KERNEL);
			if (!dwNtbInMaxSize) {
				err = -ENOMEM;
				goto size_err;
			}
			*dwNtbInMaxSize = cpu_to_le32(ctx->rx_max);

			err = usb_control_msg(ctx->udev,
					usb_sndctrlpipe(ctx->udev, 0),
					USB_CDC_SET_NTB_INPUT_SIZE,
					USB_TYPE_CLASS | USB_DIR_OUT
					 | USB_RECIP_INTERFACE,
					0, iface_no, dwNtbInMaxSize, 4, 1000);
			kfree(dwNtbInMaxSize);
		}
size_err:
		if (err < 0)
			pr_debug("Setting NTB Input Size failed\n");
	}

	/* verify maximum size of transmitted NTB in bytes */
	if ((ctx->tx_max <
	    (CDC_NCM_MIN_HDR_SIZE + CDC_NCM_MIN_DATAGRAM_SIZE)) ||
	    (ctx->tx_max > CDC_NCM_NTB_MAX_SIZE_TX)) {
		pr_debug("Using default maximum transmit length=%d\n",
						CDC_NCM_NTB_MAX_SIZE_TX);
		ctx->tx_max = CDC_NCM_NTB_MAX_SIZE_TX;
	}

	/*
	 * verify that the structure alignment is:
	 * - power of two
	 * - not greater than the maximum transmit length
	 * - not less than four bytes
	 */
	val = ctx->tx_ndp_modulus;

	if ((val < USB_CDC_NCM_NDP_ALIGN_MIN_SIZE) ||
	    (val != ((-val) & val)) || (val >= ctx->tx_max)) {
		pr_debug("Using default alignment: 4 bytes\n");
		ctx->tx_ndp_modulus = USB_CDC_NCM_NDP_ALIGN_MIN_SIZE;
	}

	/*
	 * verify that the payload alignment is:
	 * - power of two
	 * - not greater than the maximum transmit length
	 * - not less than four bytes
	 */
	val = ctx->tx_modulus;

	if ((val < USB_CDC_NCM_NDP_ALIGN_MIN_SIZE) ||
	    (val != ((-val) & val)) || (val >= ctx->tx_max)) {
		pr_debug("Using default transmit modulus: 4 bytes\n");
		ctx->tx_modulus = USB_CDC_NCM_NDP_ALIGN_MIN_SIZE;
	}

	/* verify the payload remainder */
	if (ctx->tx_remainder >= ctx->tx_modulus) {
		pr_debug("Using default transmit remainder: 0 bytes\n");
		ctx->tx_remainder = 0;
	}

	/* adjust TX-remainder according to NCM specification. */
	ctx->tx_remainder = ((ctx->tx_remainder - ETH_HLEN) &
						(ctx->tx_modulus - 1));

	/* additional configuration */

	/* set CRC Mode */
	if (flags & USB_CDC_NCM_NCAP_CRC_MODE) {
		err = usb_control_msg(ctx->udev, usb_sndctrlpipe(ctx->udev, 0),
				USB_CDC_SET_CRC_MODE,
				USB_TYPE_CLASS | USB_DIR_OUT
				 | USB_RECIP_INTERFACE,
				USB_CDC_NCM_CRC_NOT_APPENDED,
				iface_no, NULL, 0, 1000);
		if (err < 0)
			pr_debug("Setting CRC mode off failed\n");
	}

	/* set NTB format, if both formats are supported */
	if (ntb_fmt_supported & USB_CDC_NCM_NTH32_SIGN) {
		err = usb_control_msg(ctx->udev, usb_sndctrlpipe(ctx->udev, 0),
				USB_CDC_SET_NTB_FORMAT, USB_TYPE_CLASS
				 | USB_DIR_OUT | USB_RECIP_INTERFACE,
				USB_CDC_NCM_NTB16_FORMAT,
				iface_no, NULL, 0, 1000);
		if (err < 0)
			pr_debug("Setting NTB format to 16-bit failed\n");
	}

	ctx->max_datagram_size = CDC_NCM_MIN_DATAGRAM_SIZE;

	/* set Max Datagram Size (MTU) */
	if (flags & USB_CDC_NCM_NCAP_MAX_DATAGRAM_SIZE) {
		__le16 *max_datagram_size;
		u16 eth_max_sz = le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);

		max_datagram_size = kzalloc(sizeof(*max_datagram_size),
				GFP_KERNEL);
		if (!max_datagram_size) {
			err = -ENOMEM;
			goto max_dgram_err;
		}

		err = usb_control_msg(ctx->udev, usb_rcvctrlpipe(ctx->udev, 0),
				USB_CDC_GET_MAX_DATAGRAM_SIZE,
				USB_TYPE_CLASS | USB_DIR_IN
				 | USB_RECIP_INTERFACE,
				0, iface_no, max_datagram_size,
				2, 1000);
		if (err < 0) {
			pr_debug("GET_MAX_DATAGRAM_SIZE failed, use size=%u\n",
						CDC_NCM_MIN_DATAGRAM_SIZE);
		} else {
			ctx->max_datagram_size =
				le16_to_cpu(*max_datagram_size);
			/* Check Eth descriptor value */
			if (ctx->max_datagram_size > eth_max_sz)
					ctx->max_datagram_size = eth_max_sz;

			if (ctx->max_datagram_size > CDC_NCM_MAX_DATAGRAM_SIZE)
				ctx->max_datagram_size =
						CDC_NCM_MAX_DATAGRAM_SIZE;

			if (ctx->max_datagram_size < CDC_NCM_MIN_DATAGRAM_SIZE)
				ctx->max_datagram_size =
					CDC_NCM_MIN_DATAGRAM_SIZE;

			/* if value changed, update device */
			if (ctx->max_datagram_size !=
					le16_to_cpu(*max_datagram_size)) {
				err = usb_control_msg(ctx->udev,
						usb_sndctrlpipe(ctx->udev, 0),
						USB_CDC_SET_MAX_DATAGRAM_SIZE,
						USB_TYPE_CLASS | USB_DIR_OUT
						 | USB_RECIP_INTERFACE,
						0,
						iface_no, max_datagram_size,
						2, 1000);
				if (err < 0)
					pr_debug("SET_MAX_DGRAM_SIZE failed\n");
			}
		}
		kfree(max_datagram_size);
	}

max_dgram_err:
	if (ctx->netdev->mtu != (ctx->max_datagram_size - ETH_HLEN))
		ctx->netdev->mtu = ctx->max_datagram_size - ETH_HLEN;

	return 0;
}

static void
cdc_ncm_find_endpoints(struct cdc_ncm_ctx *ctx, struct usb_interface *intf)
{
	struct usb_host_endpoint *e;
	u8 ep;

	for (ep = 0; ep < intf->cur_altsetting->desc.bNumEndpoints; ep++) {

		e = intf->cur_altsetting->endpoint + ep;
		switch (e->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
		case USB_ENDPOINT_XFER_INT:
			if (usb_endpoint_dir_in(&e->desc)) {
				if (ctx->status_ep == NULL)
					ctx->status_ep = e;
			}
			break;

		case USB_ENDPOINT_XFER_BULK:
			if (usb_endpoint_dir_in(&e->desc)) {
				if (ctx->in_ep == NULL)
					ctx->in_ep = e;
			} else {
				if (ctx->out_ep == NULL)
					ctx->out_ep = e;
			}
			break;

		default:
			break;
		}
	}
}

static void cdc_ncm_free(struct cdc_ncm_ctx *ctx)
{
	if (ctx == NULL)
		return;

	if (ctx->tx_rem_skb != NULL) {
		dev_kfree_skb_any(ctx->tx_rem_skb);
		ctx->tx_rem_skb = NULL;
	}

	if (ctx->tx_curr_skb != NULL) {
		dev_kfree_skb_any(ctx->tx_curr_skb);
		ctx->tx_curr_skb = NULL;
	}

	kfree(ctx);
}

static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
{
	struct cdc_ncm_ctx *ctx;
	struct usb_driver *driver;
	u8 *buf;
	int len;
	int temp;
	u8 iface_no;

	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
	if (ctx == NULL)
		return -ENODEV;

	hrtimer_init(&ctx->tx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	ctx->tx_timer.function = &cdc_ncm_tx_timer_cb;
	ctx->bh.data = (unsigned long)ctx;
	ctx->bh.func = cdc_ncm_txpath_bh;
	atomic_set(&ctx->stop, 0);
	spin_lock_init(&ctx->mtx);
	ctx->netdev = dev->net;

	/* store ctx pointer in device data field */
	dev->data[0] = (unsigned long)ctx;

	/* get some pointers */
	driver = driver_of(intf);
	buf = intf->cur_altsetting->extra;
	len = intf->cur_altsetting->extralen;

	ctx->udev = dev->udev;
	ctx->intf = intf;

	/* parse through descriptors associated with control interface */
	while ((len > 0) && (buf[0] > 2) && (buf[0] <= len)) {

		if (buf[1] != USB_DT_CS_INTERFACE)
			goto advance;

		switch (buf[2]) {
		case USB_CDC_UNION_TYPE:
			if (buf[0] < sizeof(*(ctx->union_desc)))
				break;

			ctx->union_desc =
					(const struct usb_cdc_union_desc *)buf;

			ctx->control = usb_ifnum_to_if(dev->udev,
					ctx->union_desc->bMasterInterface0);
			ctx->data = usb_ifnum_to_if(dev->udev,
					ctx->union_desc->bSlaveInterface0);
			break;

		case USB_CDC_ETHERNET_TYPE:
			if (buf[0] < sizeof(*(ctx->ether_desc)))
				break;

			ctx->ether_desc =
					(const struct usb_cdc_ether_desc *)buf;
			dev->hard_mtu =
				le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);

			if (dev->hard_mtu < CDC_NCM_MIN_DATAGRAM_SIZE)
				dev->hard_mtu =	CDC_NCM_MIN_DATAGRAM_SIZE;
			else if (dev->hard_mtu > CDC_NCM_MAX_DATAGRAM_SIZE)
				dev->hard_mtu =	CDC_NCM_MAX_DATAGRAM_SIZE;
			break;

		case USB_CDC_NCM_TYPE:
			if (buf[0] < sizeof(*(ctx->func_desc)))
				break;

			ctx->func_desc = (const struct usb_cdc_ncm_desc *)buf;
			break;

		default:
			break;
		}
advance:
		/* advance to next descriptor */
		temp = buf[0];
		buf += temp;
		len -= temp;
	}

	/* check if we got everything */
	if ((ctx->control == NULL) || (ctx->data == NULL) ||
	    (ctx->ether_desc == NULL) || (ctx->control != intf))
		goto error;

	/* claim interfaces, if any */
	temp = usb_driver_claim_interface(driver, ctx->data, dev);
	if (temp)
		goto error;

	iface_no = ctx->data->cur_altsetting->desc.bInterfaceNumber;

	/* reset data interface */
	temp = usb_set_interface(dev->udev, iface_no, 0);
	if (temp)
		goto error2;

	/* initialize data interface */
	if (cdc_ncm_setup(ctx))
		goto error2;

	/* configure data interface */
	temp = usb_set_interface(dev->udev, iface_no, 1);
	if (temp)
		goto error2;

	cdc_ncm_find_endpoints(ctx, ctx->data);
	cdc_ncm_find_endpoints(ctx, ctx->control);

	if ((ctx->in_ep == NULL) || (ctx->out_ep == NULL) ||
	    (ctx->status_ep == NULL))
		goto error2;

	dev->net->ethtool_ops = &cdc_ncm_ethtool_ops;

	usb_set_intfdata(ctx->data, dev);
	usb_set_intfdata(ctx->control, dev);
	usb_set_intfdata(ctx->intf, dev);

	temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
	if (temp)
		goto error2;

	dev_info(&dev->udev->dev, "MAC-Address: %pM\n", dev->net->dev_addr);

	dev->in = usb_rcvbulkpipe(dev->udev,
		ctx->in_ep->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	dev->out = usb_sndbulkpipe(dev->udev,
		ctx->out_ep->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	dev->status = ctx->status_ep;
	dev->rx_urb_size = ctx->rx_max;

	/*
	 * We should get an event when network connection is "connected" or
	 * "disconnected". Set network connection in "disconnected" state
	 * (carrier is OFF) during attach, so the IP network stack does not
	 * start IPv6 negotiation and more.
	 */
	netif_carrier_off(dev->net);
	ctx->tx_speed = ctx->rx_speed = 0;
	return 0;

error2:
	usb_set_intfdata(ctx->control, NULL);
	usb_set_intfdata(ctx->data, NULL);
	usb_driver_release_interface(driver, ctx->data);
error:
	cdc_ncm_free((struct cdc_ncm_ctx *)dev->data[0]);
	dev->data[0] = 0;
	dev_info(&dev->udev->dev, "bind() failure\n");
	return -ENODEV;
}

static void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf)
{
	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
	struct usb_driver *driver = driver_of(intf);

	if (ctx == NULL)
		return;		/* no setup */

	atomic_set(&ctx->stop, 1);

	if (hrtimer_active(&ctx->tx_timer))
		hrtimer_cancel(&ctx->tx_timer);

	tasklet_kill(&ctx->bh);

	/* disconnect master --> disconnect slave */
	if (intf == ctx->control && ctx->data) {
		usb_set_intfdata(ctx->data, NULL);
		usb_driver_release_interface(driver, ctx->data);
		ctx->data = NULL;

	} else if (intf == ctx->data && ctx->control) {
		usb_set_intfdata(ctx->control, NULL);
		usb_driver_release_interface(driver, ctx->control);
		ctx->control = NULL;
	}

	usb_set_intfdata(ctx->intf, NULL);
	cdc_ncm_free(ctx);
}

static void cdc_ncm_zero_fill(u8 *ptr, u32 first, u32 end, u32 max)
{
	if (first >= max)
		return;
	if (first >= end)
		return;
	if (end > max)
		end = max;
	memset(ptr + first, 0, end - first);
}

static struct sk_buff *
cdc_ncm_fill_tx_frame(struct cdc_ncm_ctx *ctx, struct sk_buff *skb)
{
	struct sk_buff *skb_out;
	u32 rem;
	u32 offset;
	u32 last_offset;
	u16 n = 0, index;
	u8 ready2send = 0;

	/* if there is a remaining skb, it gets priority */
	if (skb != NULL)
		swap(skb, ctx->tx_rem_skb);
	else
		ready2send = 1;

	/*
	 * +----------------+
	 * | skb_out        |
	 * +----------------+
	 *           ^ offset
	 *        ^ last_offset
	 */

	/* check if we are resuming an OUT skb */
	if (ctx->tx_curr_skb != NULL) {
		/* pop variables */
		skb_out = ctx->tx_curr_skb;
		offset = ctx->tx_curr_offset;
		last_offset = ctx->tx_curr_last_offset;
		n = ctx->tx_curr_frame_num;

	} else {
		/* reset variables */
		skb_out = alloc_skb((ctx->tx_max + 1), GFP_ATOMIC);
		if (skb_out == NULL) {
			if (skb != NULL) {
				dev_kfree_skb_any(skb);
				ctx->netdev->stats.tx_dropped++;
			}
			goto exit_no_skb;
		}

		/* make room for NTH and NDP */
		offset = ALIGN(sizeof(struct usb_cdc_ncm_nth16),
					ctx->tx_ndp_modulus) +
					sizeof(struct usb_cdc_ncm_ndp16) +
					(ctx->tx_max_datagrams + 1) *
					sizeof(struct usb_cdc_ncm_dpe16);

		/* store last valid offset before alignment */
		last_offset = offset;
		/* align first Datagram offset correctly */
		offset = ALIGN(offset, ctx->tx_modulus) + ctx->tx_remainder;
		/* zero buffer till the first IP datagram */
		cdc_ncm_zero_fill(skb_out->data, 0, offset, offset);
		n = 0;
		ctx->tx_curr_frame_num = 0;
	}

	for (; n < ctx->tx_max_datagrams; n++) {
		/* check if end of transmit buffer is reached */
		if (offset >= ctx->tx_max) {
			ready2send = 1;
			break;
		}
		/* compute maximum buffer size */
		rem = ctx->tx_max - offset;

		if (skb == NULL) {
			skb = ctx->tx_rem_skb;
			ctx->tx_rem_skb = NULL;

			/* check for end of skb */
			if (skb == NULL)
				break;
		}

		if (skb->len > rem) {
			if (n == 0) {
				/* won't fit, MTU problem? */
				dev_kfree_skb_any(skb);
				skb = NULL;
				ctx->netdev->stats.tx_dropped++;
			} else {
				/* no room for skb - store for later */
				if (ctx->tx_rem_skb != NULL) {
					dev_kfree_skb_any(ctx->tx_rem_skb);
					ctx->netdev->stats.tx_dropped++;
				}
				ctx->tx_rem_skb = skb;
				skb = NULL;
				ready2send = 1;
			}
			break;
		}

		memcpy(((u8 *)skb_out->data) + offset, skb->data, skb->len);

		ctx->tx_ncm.dpe16[n].wDatagramLength = cpu_to_le16(skb->len);
		ctx->tx_ncm.dpe16[n].wDatagramIndex = cpu_to_le16(offset);

		/* update offset */
		offset += skb->len;

		/* store last valid offset before alignment */
		last_offset = offset;

		/* align offset correctly */
		offset = ALIGN(offset, ctx->tx_modulus) + ctx->tx_remainder;

		/* zero padding */
		cdc_ncm_zero_fill(skb_out->data, last_offset, offset,
								ctx->tx_max);
		dev_kfree_skb_any(skb);
		skb = NULL;
	}

	/* free up any dangling skb */
	if (skb != NULL) {
		dev_kfree_skb_any(skb);
		skb = NULL;
		ctx->netdev->stats.tx_dropped++;
	}

	ctx->tx_curr_frame_num = n;

	if (n == 0) {
		/* wait for more frames */
		/* push variables */
		ctx->tx_curr_skb = skb_out;
		ctx->tx_curr_offset = offset;
		ctx->tx_curr_last_offset = last_offset;
		goto exit_no_skb;

	} else if ((n < ctx->tx_max_datagrams) && (ready2send == 0)) {
		/* wait for more frames */
		/* push variables */
		ctx->tx_curr_skb = skb_out;
		ctx->tx_curr_offset = offset;
		ctx->tx_curr_last_offset = last_offset;
		/* set the pending count */
		if (n < CDC_NCM_RESTART_TIMER_DATAGRAM_CNT)
			ctx->tx_timer_pending = CDC_NCM_TIMER_PENDING_CNT;
		goto exit_no_skb;

	} else {
		/* frame goes out */
		/* variables will be reset at next call */
	}

	/* check for overflow */
	if (last_offset > ctx->tx_max)
		last_offset = ctx->tx_max;

	/* revert offset */
	offset = last_offset;

	/*
	 * If collected data size is less or equal CDC_NCM_MIN_TX_PKT bytes,
	 * we send buffers as it is. If we get more data, it would be more
	 * efficient for USB HS mobile device with DMA engine to receive a full
	 * size NTB, than canceling DMA transfer and receiving a short packet.
	 */
	if (offset > CDC_NCM_MIN_TX_PKT)
		offset = ctx->tx_max;

	/* final zero padding */
	cdc_ncm_zero_fill(skb_out->data, last_offset, offset, ctx->tx_max);

	/* store last offset */
	last_offset = offset;

	if (((last_offset < ctx->tx_max) && ((last_offset %
			le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0)) ||
	    (((last_offset == ctx->tx_max) && ((ctx->tx_max %
		le16_to_cpu(ctx->out_ep->desc.wMaxPacketSize)) == 0)) &&
		(ctx->tx_max < le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize)))) {
		/* force short packet */
		*(((u8 *)skb_out->data) + last_offset) = 0;
		last_offset++;
	}

	/* zero the rest of the DPEs plus the last NULL entry */
	for (; n <= CDC_NCM_DPT_DATAGRAMS_MAX; n++) {
		ctx->tx_ncm.dpe16[n].wDatagramLength = 0;
		ctx->tx_ncm.dpe16[n].wDatagramIndex = 0;
	}

	/* fill out 16-bit NTB header */
	ctx->tx_ncm.nth16.dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN);
	ctx->tx_ncm.nth16.wHeaderLength =
					cpu_to_le16(sizeof(ctx->tx_ncm.nth16));
	ctx->tx_ncm.nth16.wSequence = cpu_to_le16(ctx->tx_seq);
	ctx->tx_ncm.nth16.wBlockLength = cpu_to_le16(last_offset);
	index = ALIGN(sizeof(struct usb_cdc_ncm_nth16), ctx->tx_ndp_modulus);
	ctx->tx_ncm.nth16.wNdpIndex = cpu_to_le16(index);

	memcpy(skb_out->data, &(ctx->tx_ncm.nth16), sizeof(ctx->tx_ncm.nth16));
	ctx->tx_seq++;

	/* fill out 16-bit NDP table */
	ctx->tx_ncm.ndp16.dwSignature =
				cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN);
	rem = sizeof(ctx->tx_ncm.ndp16) + ((ctx->tx_curr_frame_num + 1) *
					sizeof(struct usb_cdc_ncm_dpe16));
	ctx->tx_ncm.ndp16.wLength = cpu_to_le16(rem);
	ctx->tx_ncm.ndp16.wNextNdpIndex = 0; /* reserved */

	memcpy(((u8 *)skb_out->data) + index,
						&(ctx->tx_ncm.ndp16),
						sizeof(ctx->tx_ncm.ndp16));

	memcpy(((u8 *)skb_out->data) + index + sizeof(ctx->tx_ncm.ndp16),
					&(ctx->tx_ncm.dpe16),
					(ctx->tx_curr_frame_num + 1) *
					sizeof(struct usb_cdc_ncm_dpe16));

	/* set frame length */
	skb_put(skb_out, last_offset);

	/* return skb */
	ctx->tx_curr_skb = NULL;
	ctx->netdev->stats.tx_packets += ctx->tx_curr_frame_num;
	return skb_out;

exit_no_skb:
	/* Start timer, if there is a remaining skb */
	if (ctx->tx_curr_skb != NULL)
		cdc_ncm_tx_timeout_start(ctx);
	return NULL;
}

static void cdc_ncm_tx_timeout_start(struct cdc_ncm_ctx *ctx)
{
	/* start timer, if not already started */
	if (!(hrtimer_active(&ctx->tx_timer) || atomic_read(&ctx->stop)))
		hrtimer_start(&ctx->tx_timer,
				ktime_set(0, CDC_NCM_TIMER_INTERVAL),
				HRTIMER_MODE_REL);
}

static enum hrtimer_restart cdc_ncm_tx_timer_cb(struct hrtimer *timer)
{
	struct cdc_ncm_ctx *ctx =
			container_of(timer, struct cdc_ncm_ctx, tx_timer);

	if (!atomic_read(&ctx->stop))
		tasklet_schedule(&ctx->bh);
	return HRTIMER_NORESTART;
}

static void cdc_ncm_txpath_bh(unsigned long param)
{
	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)param;

	spin_lock_bh(&ctx->mtx);
	if (ctx->tx_timer_pending != 0) {
		ctx->tx_timer_pending--;
		cdc_ncm_tx_timeout_start(ctx);
		spin_unlock_bh(&ctx->mtx);
	} else if (ctx->netdev != NULL) {
		spin_unlock_bh(&ctx->mtx);
		netif_tx_lock_bh(ctx->netdev);
		usbnet_start_xmit(NULL, ctx->netdev);
		netif_tx_unlock_bh(ctx->netdev);
	}
}

static struct sk_buff *
cdc_ncm_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
{
	struct sk_buff *skb_out;
	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];

	/*
	 * The Ethernet API we are using does not support transmitting
	 * multiple Ethernet frames in a single call. This driver will
	 * accumulate multiple Ethernet frames and send out a larger
	 * USB frame when the USB buffer is full or when a single jiffies
	 * timeout happens.
	 */
	if (ctx == NULL)
		goto error;

	spin_lock_bh(&ctx->mtx);
	skb_out = cdc_ncm_fill_tx_frame(ctx, skb);
	spin_unlock_bh(&ctx->mtx);
	return skb_out;

error:
	if (skb != NULL)
		dev_kfree_skb_any(skb);

	return NULL;
}

static int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
{
	struct sk_buff *skb;
	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
	int len;
	int nframes;
	int x;
	int offset;
	struct usb_cdc_ncm_nth16 *nth16;
	struct usb_cdc_ncm_ndp16 *ndp16;
	struct usb_cdc_ncm_dpe16 *dpe16;

	if (ctx == NULL)
		goto error;

	if (skb_in->len < (sizeof(struct usb_cdc_ncm_nth16) +
					sizeof(struct usb_cdc_ncm_ndp16))) {
		pr_debug("frame too short\n");
		goto error;
	}

	nth16 = (struct usb_cdc_ncm_nth16 *)skb_in->data;

	if (le32_to_cpu(nth16->dwSignature) != USB_CDC_NCM_NTH16_SIGN) {
		pr_debug("invalid NTH16 signature <%u>\n",
					le32_to_cpu(nth16->dwSignature));
		goto error;
	}

	len = le16_to_cpu(nth16->wBlockLength);
	if (len > ctx->rx_max) {
		pr_debug("unsupported NTB block length %u/%u\n", len,
								ctx->rx_max);
		goto error;
	}

	if ((ctx->rx_seq + 1) != le16_to_cpu(nth16->wSequence) &&
		(ctx->rx_seq || le16_to_cpu(nth16->wSequence)) &&
		!((ctx->rx_seq == 0xffff) && !le16_to_cpu(nth16->wSequence))) {
		pr_debug("sequence number glitch prev=%d curr=%d\n",
				ctx->rx_seq, le16_to_cpu(nth16->wSequence));
	}
	ctx->rx_seq = le16_to_cpu(nth16->wSequence);

	len = le16_to_cpu(nth16->wNdpIndex);
	if ((len + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len) {
		pr_debug("invalid DPT16 index <%u>\n",
					le16_to_cpu(nth16->wNdpIndex));
		goto error;
	}

	ndp16 = (struct usb_cdc_ncm_ndp16 *)(((u8 *)skb_in->data) + len);

	if (le32_to_cpu(ndp16->dwSignature) != USB_CDC_NCM_NDP16_NOCRC_SIGN) {
		pr_debug("invalid DPT16 signature <%u>\n",
					le32_to_cpu(ndp16->dwSignature));
		goto error;
	}

	if (le16_to_cpu(ndp16->wLength) < USB_CDC_NCM_NDP16_LENGTH_MIN) {
		pr_debug("invalid DPT16 length <%u>\n",
					le32_to_cpu(ndp16->dwSignature));
		goto error;
	}

	nframes = ((le16_to_cpu(ndp16->wLength) -
					sizeof(struct usb_cdc_ncm_ndp16)) /
					sizeof(struct usb_cdc_ncm_dpe16));
	nframes--; /* we process NDP entries except for the last one */

	len += sizeof(struct usb_cdc_ncm_ndp16);

	if ((len + nframes * (sizeof(struct usb_cdc_ncm_dpe16))) >
								skb_in->len) {
		pr_debug("Invalid nframes = %d\n", nframes);
		goto error;
	}

	dpe16 = (struct usb_cdc_ncm_dpe16 *)(((u8 *)skb_in->data) + len);

	for (x = 0; x < nframes; x++, dpe16++) {
		offset = le16_to_cpu(dpe16->wDatagramIndex);
		len = le16_to_cpu(dpe16->wDatagramLength);

		/*
		 * CDC NCM ch. 3.7
		 * All entries after first NULL entry are to be ignored
		 */
		if ((offset == 0) || (len == 0)) {
			if (!x)
				goto error; /* empty NTB */
			break;
		}

		/* sanity checking */
		if (((offset + len) > skb_in->len) ||
				(len > ctx->rx_max) || (len < ETH_HLEN)) {
			pr_debug("invalid frame detected (ignored)"
					"offset[%u]=%u, length=%u, skb=%p\n",
					x, offset, len, skb_in);
			if (!x)
				goto error;
			break;

		} else {
			skb = skb_clone(skb_in, GFP_ATOMIC);
			if (!skb)
				goto error;
			skb->len = len;
			skb->data = ((u8 *)skb_in->data) + offset;
			skb_set_tail_pointer(skb, len);
			usbnet_skb_return(dev, skb);
		}
	}
	return 1;
error:
	return 0;
}

static void
cdc_ncm_speed_change(struct cdc_ncm_ctx *ctx,
		     struct usb_cdc_speed_change *data)
{
	uint32_t rx_speed = le32_to_cpu(data->DLBitRRate);
	uint32_t tx_speed = le32_to_cpu(data->ULBitRate);

	/*
	 * Currently the USB-NET API does not support reporting the actual
	 * device speed. Do print it instead.
	 */
	if ((tx_speed != ctx->tx_speed) || (rx_speed != ctx->rx_speed)) {
		ctx->tx_speed = tx_speed;
		ctx->rx_speed = rx_speed;

		if ((tx_speed > 1000000) && (rx_speed > 1000000)) {
			printk(KERN_INFO KBUILD_MODNAME
				": %s: %u mbit/s downlink "
				"%u mbit/s uplink\n",
				ctx->netdev->name,
				(unsigned int)(rx_speed / 1000000U),
				(unsigned int)(tx_speed / 1000000U));
		} else {
			printk(KERN_INFO KBUILD_MODNAME
				": %s: %u kbit/s downlink "
				"%u kbit/s uplink\n",
				ctx->netdev->name,
				(unsigned int)(rx_speed / 1000U),
				(unsigned int)(tx_speed / 1000U));
		}
	}
}

static void cdc_ncm_status(struct usbnet *dev, struct urb *urb)
{
	struct cdc_ncm_ctx *ctx;
	struct usb_cdc_notification *event;

	ctx = (struct cdc_ncm_ctx *)dev->data[0];

	if (urb->actual_length < sizeof(*event))
		return;

	/* test for split data in 8-byte chunks */
	if (test_and_clear_bit(EVENT_STS_SPLIT, &dev->flags)) {
		cdc_ncm_speed_change(ctx,
		      (struct usb_cdc_speed_change *)urb->transfer_buffer);
		return;
	}

	event = urb->transfer_buffer;

	switch (event->bNotificationType) {
	case USB_CDC_NOTIFY_NETWORK_CONNECTION:
		/*
		 * According to the CDC NCM specification ch.7.1
		 * USB_CDC_NOTIFY_NETWORK_CONNECTION notification shall be
		 * sent by device after USB_CDC_NOTIFY_SPEED_CHANGE.
		 */
		ctx->connected = event->wValue;

		printk(KERN_INFO KBUILD_MODNAME ": %s: network connection:"
			" %sconnected\n",
			ctx->netdev->name, ctx->connected ? "" : "dis");

		if (ctx->connected)
			netif_carrier_on(dev->net);
		else {
			netif_carrier_off(dev->net);
			ctx->tx_speed = ctx->rx_speed = 0;
		}
		break;

	case USB_CDC_NOTIFY_SPEED_CHANGE:
		if (urb->actual_length < (sizeof(*event) +
					sizeof(struct usb_cdc_speed_change)))
			set_bit(EVENT_STS_SPLIT, &dev->flags);
		else
			cdc_ncm_speed_change(ctx,
				(struct usb_cdc_speed_change *) &event[1]);
		break;

	default:
		dev_err(&dev->udev->dev, "NCM: unexpected "
			"notification 0x%02x!\n", event->bNotificationType);
		break;
	}
}

static int cdc_ncm_check_connect(struct usbnet *dev)
{
	struct cdc_ncm_ctx *ctx;

	ctx = (struct cdc_ncm_ctx *)dev->data[0];
	if (ctx == NULL)
		return 1;	/* disconnected */

	return !ctx->connected;
}

static int
cdc_ncm_probe(struct usb_interface *udev, const struct usb_device_id *prod)
{
	return usbnet_probe(udev, prod);
}

static void cdc_ncm_disconnect(struct usb_interface *intf)
{
	struct usbnet *dev = usb_get_intfdata(intf);

	if (dev == NULL)
		return;		/* already disconnected */

	usbnet_disconnect(intf);
}

static int cdc_ncm_manage_power(struct usbnet *dev, int status)
{
	dev->intf->needs_remote_wakeup = status;
	return 0;
}

static const struct driver_info cdc_ncm_info = {
	.description = "CDC NCM",
	.flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET,
	.bind = cdc_ncm_bind,
	.unbind = cdc_ncm_unbind,
	.check_connect = cdc_ncm_check_connect,
	.manage_power = cdc_ncm_manage_power,
	.status = cdc_ncm_status,
	.rx_fixup = cdc_ncm_rx_fixup,
	.tx_fixup = cdc_ncm_tx_fixup,
};

static struct usb_driver cdc_ncm_driver = {
	.name = "cdc_ncm",
	.id_table = cdc_devs,
	.probe = cdc_ncm_probe,
	.disconnect = cdc_ncm_disconnect,
	.suspend = usbnet_suspend,
	.resume = usbnet_resume,
	.reset_resume =	usbnet_resume,
	.supports_autosuspend = 1,
	.disable_hub_initiated_lpm = 1,
};

static const struct ethtool_ops cdc_ncm_ethtool_ops = {
	.get_drvinfo = cdc_ncm_get_drvinfo,
	.get_link = usbnet_get_link,
	.get_msglevel = usbnet_get_msglevel,
	.set_msglevel = usbnet_set_msglevel,
	.get_settings = usbnet_get_settings,
	.set_settings = usbnet_set_settings,
	.nway_reset = usbnet_nway_reset,
};

module_usb_driver(cdc_ncm_driver);

MODULE_AUTHOR("Hans Petter Selasky");
MODULE_DESCRIPTION("USB CDC NCM host driver");
MODULE_LICENSE("Dual BSD/GPL");