xref: /linux/drivers/usb/gadget/function/f_ncm.c (revision 4b660dbd9ee2059850fd30e0df420ca7a38a1856)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * f_ncm.c -- USB CDC Network (NCM) link function driver
4  *
5  * Copyright (C) 2010 Nokia Corporation
6  * Contact: Yauheni Kaliuta <yauheni.kaliuta@nokia.com>
7  *
8  * The driver borrows from f_ecm.c which is:
9  *
10  * Copyright (C) 2003-2005,2008 David Brownell
11  * Copyright (C) 2008 Nokia Corporation
12  */
13 
14 #include <linux/kernel.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/device.h>
18 #include <linux/etherdevice.h>
19 #include <linux/crc32.h>
20 
21 #include <linux/usb/cdc.h>
22 
23 #include "u_ether.h"
24 #include "u_ether_configfs.h"
25 #include "u_ncm.h"
26 #include "configfs.h"
27 
28 /*
29  * This function is a "CDC Network Control Model" (CDC NCM) Ethernet link.
30  * NCM is intended to be used with high-speed network attachments.
31  *
32  * Note that NCM requires the use of "alternate settings" for its data
33  * interface.  This means that the set_alt() method has real work to do,
34  * and also means that a get_alt() method is required.
35  */
36 
37 /* to trigger crc/non-crc ndp signature */
38 
39 #define NCM_NDP_HDR_CRC		0x01000000
40 
41 enum ncm_notify_state {
42 	NCM_NOTIFY_NONE,		/* don't notify */
43 	NCM_NOTIFY_CONNECT,		/* issue CONNECT next */
44 	NCM_NOTIFY_SPEED,		/* issue SPEED_CHANGE next */
45 };
46 
47 struct f_ncm {
48 	struct gether			port;
49 	u8				ctrl_id, data_id;
50 
51 	char				ethaddr[14];
52 
53 	struct usb_ep			*notify;
54 	struct usb_request		*notify_req;
55 	u8				notify_state;
56 	atomic_t			notify_count;
57 	bool				is_open;
58 
59 	const struct ndp_parser_opts	*parser_opts;
60 	bool				is_crc;
61 	u32				ndp_sign;
62 
63 	/*
64 	 * for notification, it is accessed from both
65 	 * callback and ethernet open/close
66 	 */
67 	spinlock_t			lock;
68 
69 	struct net_device		*netdev;
70 
71 	/* For multi-frame NDP TX */
72 	struct sk_buff			*skb_tx_data;
73 	struct sk_buff			*skb_tx_ndp;
74 	u16				ndp_dgram_count;
75 	struct hrtimer			task_timer;
76 };
77 
78 static inline struct f_ncm *func_to_ncm(struct usb_function *f)
79 {
80 	return container_of(f, struct f_ncm, port.func);
81 }
82 
83 /*-------------------------------------------------------------------------*/
84 
85 /*
86  * We cannot group frames so use just the minimal size which ok to put
87  * one max-size ethernet frame.
88  * If the host can group frames, allow it to do that, 16K is selected,
89  * because it's used by default by the current linux host driver
90  */
91 #define NTB_DEFAULT_IN_SIZE	16384
92 #define NTB_OUT_SIZE		16384
93 
94 /* Allocation for storing the NDP, 32 should suffice for a
95  * 16k packet. This allows a maximum of 32 * 507 Byte packets to
96  * be transmitted in a single 16kB skb, though when sending full size
97  * packets this limit will be plenty.
98  * Smaller packets are not likely to be trying to maximize the
99  * throughput and will be mstly sending smaller infrequent frames.
100  */
101 #define TX_MAX_NUM_DPE		32
102 
103 /* Delay for the transmit to wait before sending an unfilled NTB frame. */
104 #define TX_TIMEOUT_NSECS	300000
105 
106 /*
107  * Although max mtu as dictated by u_ether is 15412 bytes, setting
108  * max_segment_size to 15426 would not be efficient. If user chooses segment
109  * size to be (>= 8192), then we can't aggregate more than one buffer in each
110  * NTB (assuming each packet coming from network layer is >= 8192 bytes) as ep
111  * maxpacket limit is 16384. So let max_segment_size be limited to 8000 to allow
112  * at least 2 packets to be aggregated reducing wastage of NTB buffer space
113  */
114 #define MAX_DATAGRAM_SIZE	8000
115 
116 #define FORMATS_SUPPORTED	(USB_CDC_NCM_NTB16_SUPPORTED |	\
117 				 USB_CDC_NCM_NTB32_SUPPORTED)
118 
119 static struct usb_cdc_ncm_ntb_parameters ntb_parameters = {
120 	.wLength = cpu_to_le16(sizeof(ntb_parameters)),
121 	.bmNtbFormatsSupported = cpu_to_le16(FORMATS_SUPPORTED),
122 	.dwNtbInMaxSize = cpu_to_le32(NTB_DEFAULT_IN_SIZE),
123 	.wNdpInDivisor = cpu_to_le16(4),
124 	.wNdpInPayloadRemainder = cpu_to_le16(0),
125 	.wNdpInAlignment = cpu_to_le16(4),
126 
127 	.dwNtbOutMaxSize = cpu_to_le32(NTB_OUT_SIZE),
128 	.wNdpOutDivisor = cpu_to_le16(4),
129 	.wNdpOutPayloadRemainder = cpu_to_le16(0),
130 	.wNdpOutAlignment = cpu_to_le16(4),
131 };
132 
133 /*
134  * Use wMaxPacketSize big enough to fit CDC_NOTIFY_SPEED_CHANGE in one
135  * packet, to simplify cancellation; and a big transfer interval, to
136  * waste less bandwidth.
137  */
138 
139 #define NCM_STATUS_INTERVAL_MS		32
140 #define NCM_STATUS_BYTECOUNT		16	/* 8 byte header + data */
141 
142 static struct usb_interface_assoc_descriptor ncm_iad_desc = {
143 	.bLength =		sizeof ncm_iad_desc,
144 	.bDescriptorType =	USB_DT_INTERFACE_ASSOCIATION,
145 
146 	/* .bFirstInterface =	DYNAMIC, */
147 	.bInterfaceCount =	2,	/* control + data */
148 	.bFunctionClass =	USB_CLASS_COMM,
149 	.bFunctionSubClass =	USB_CDC_SUBCLASS_NCM,
150 	.bFunctionProtocol =	USB_CDC_PROTO_NONE,
151 	/* .iFunction =		DYNAMIC */
152 };
153 
154 /* interface descriptor: */
155 
156 static struct usb_interface_descriptor ncm_control_intf = {
157 	.bLength =		sizeof ncm_control_intf,
158 	.bDescriptorType =	USB_DT_INTERFACE,
159 
160 	/* .bInterfaceNumber = DYNAMIC */
161 	.bNumEndpoints =	1,
162 	.bInterfaceClass =	USB_CLASS_COMM,
163 	.bInterfaceSubClass =	USB_CDC_SUBCLASS_NCM,
164 	.bInterfaceProtocol =	USB_CDC_PROTO_NONE,
165 	/* .iInterface = DYNAMIC */
166 };
167 
168 static struct usb_cdc_header_desc ncm_header_desc = {
169 	.bLength =		sizeof ncm_header_desc,
170 	.bDescriptorType =	USB_DT_CS_INTERFACE,
171 	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,
172 
173 	.bcdCDC =		cpu_to_le16(0x0110),
174 };
175 
176 static struct usb_cdc_union_desc ncm_union_desc = {
177 	.bLength =		sizeof(ncm_union_desc),
178 	.bDescriptorType =	USB_DT_CS_INTERFACE,
179 	.bDescriptorSubType =	USB_CDC_UNION_TYPE,
180 	/* .bMasterInterface0 =	DYNAMIC */
181 	/* .bSlaveInterface0 =	DYNAMIC */
182 };
183 
184 static struct usb_cdc_ether_desc ecm_desc = {
185 	.bLength =		sizeof ecm_desc,
186 	.bDescriptorType =	USB_DT_CS_INTERFACE,
187 	.bDescriptorSubType =	USB_CDC_ETHERNET_TYPE,
188 
189 	/* this descriptor actually adds value, surprise! */
190 	/* .iMACAddress = DYNAMIC */
191 	.bmEthernetStatistics =	cpu_to_le32(0), /* no statistics */
192 	.wNumberMCFilters =	cpu_to_le16(0),
193 	.bNumberPowerFilters =	0,
194 };
195 
196 #define NCAPS	(USB_CDC_NCM_NCAP_ETH_FILTER | USB_CDC_NCM_NCAP_CRC_MODE)
197 
198 static struct usb_cdc_ncm_desc ncm_desc = {
199 	.bLength =		sizeof ncm_desc,
200 	.bDescriptorType =	USB_DT_CS_INTERFACE,
201 	.bDescriptorSubType =	USB_CDC_NCM_TYPE,
202 
203 	.bcdNcmVersion =	cpu_to_le16(0x0100),
204 	/* can process SetEthernetPacketFilter */
205 	.bmNetworkCapabilities = NCAPS,
206 };
207 
208 /* the default data interface has no endpoints ... */
209 
210 static struct usb_interface_descriptor ncm_data_nop_intf = {
211 	.bLength =		sizeof ncm_data_nop_intf,
212 	.bDescriptorType =	USB_DT_INTERFACE,
213 
214 	.bInterfaceNumber =	1,
215 	.bAlternateSetting =	0,
216 	.bNumEndpoints =	0,
217 	.bInterfaceClass =	USB_CLASS_CDC_DATA,
218 	.bInterfaceSubClass =	0,
219 	.bInterfaceProtocol =	USB_CDC_NCM_PROTO_NTB,
220 	/* .iInterface = DYNAMIC */
221 };
222 
223 /* ... but the "real" data interface has two bulk endpoints */
224 
225 static struct usb_interface_descriptor ncm_data_intf = {
226 	.bLength =		sizeof ncm_data_intf,
227 	.bDescriptorType =	USB_DT_INTERFACE,
228 
229 	.bInterfaceNumber =	1,
230 	.bAlternateSetting =	1,
231 	.bNumEndpoints =	2,
232 	.bInterfaceClass =	USB_CLASS_CDC_DATA,
233 	.bInterfaceSubClass =	0,
234 	.bInterfaceProtocol =	USB_CDC_NCM_PROTO_NTB,
235 	/* .iInterface = DYNAMIC */
236 };
237 
238 /* full speed support: */
239 
240 static struct usb_endpoint_descriptor fs_ncm_notify_desc = {
241 	.bLength =		USB_DT_ENDPOINT_SIZE,
242 	.bDescriptorType =	USB_DT_ENDPOINT,
243 
244 	.bEndpointAddress =	USB_DIR_IN,
245 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
246 	.wMaxPacketSize =	cpu_to_le16(NCM_STATUS_BYTECOUNT),
247 	.bInterval =		NCM_STATUS_INTERVAL_MS,
248 };
249 
250 static struct usb_endpoint_descriptor fs_ncm_in_desc = {
251 	.bLength =		USB_DT_ENDPOINT_SIZE,
252 	.bDescriptorType =	USB_DT_ENDPOINT,
253 
254 	.bEndpointAddress =	USB_DIR_IN,
255 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
256 };
257 
258 static struct usb_endpoint_descriptor fs_ncm_out_desc = {
259 	.bLength =		USB_DT_ENDPOINT_SIZE,
260 	.bDescriptorType =	USB_DT_ENDPOINT,
261 
262 	.bEndpointAddress =	USB_DIR_OUT,
263 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
264 };
265 
266 static struct usb_descriptor_header *ncm_fs_function[] = {
267 	(struct usb_descriptor_header *) &ncm_iad_desc,
268 	/* CDC NCM control descriptors */
269 	(struct usb_descriptor_header *) &ncm_control_intf,
270 	(struct usb_descriptor_header *) &ncm_header_desc,
271 	(struct usb_descriptor_header *) &ncm_union_desc,
272 	(struct usb_descriptor_header *) &ecm_desc,
273 	(struct usb_descriptor_header *) &ncm_desc,
274 	(struct usb_descriptor_header *) &fs_ncm_notify_desc,
275 	/* data interface, altsettings 0 and 1 */
276 	(struct usb_descriptor_header *) &ncm_data_nop_intf,
277 	(struct usb_descriptor_header *) &ncm_data_intf,
278 	(struct usb_descriptor_header *) &fs_ncm_in_desc,
279 	(struct usb_descriptor_header *) &fs_ncm_out_desc,
280 	NULL,
281 };
282 
283 /* high speed support: */
284 
285 static struct usb_endpoint_descriptor hs_ncm_notify_desc = {
286 	.bLength =		USB_DT_ENDPOINT_SIZE,
287 	.bDescriptorType =	USB_DT_ENDPOINT,
288 
289 	.bEndpointAddress =	USB_DIR_IN,
290 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
291 	.wMaxPacketSize =	cpu_to_le16(NCM_STATUS_BYTECOUNT),
292 	.bInterval =		USB_MS_TO_HS_INTERVAL(NCM_STATUS_INTERVAL_MS),
293 };
294 static struct usb_endpoint_descriptor hs_ncm_in_desc = {
295 	.bLength =		USB_DT_ENDPOINT_SIZE,
296 	.bDescriptorType =	USB_DT_ENDPOINT,
297 
298 	.bEndpointAddress =	USB_DIR_IN,
299 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
300 	.wMaxPacketSize =	cpu_to_le16(512),
301 };
302 
303 static struct usb_endpoint_descriptor hs_ncm_out_desc = {
304 	.bLength =		USB_DT_ENDPOINT_SIZE,
305 	.bDescriptorType =	USB_DT_ENDPOINT,
306 
307 	.bEndpointAddress =	USB_DIR_OUT,
308 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
309 	.wMaxPacketSize =	cpu_to_le16(512),
310 };
311 
312 static struct usb_descriptor_header *ncm_hs_function[] = {
313 	(struct usb_descriptor_header *) &ncm_iad_desc,
314 	/* CDC NCM control descriptors */
315 	(struct usb_descriptor_header *) &ncm_control_intf,
316 	(struct usb_descriptor_header *) &ncm_header_desc,
317 	(struct usb_descriptor_header *) &ncm_union_desc,
318 	(struct usb_descriptor_header *) &ecm_desc,
319 	(struct usb_descriptor_header *) &ncm_desc,
320 	(struct usb_descriptor_header *) &hs_ncm_notify_desc,
321 	/* data interface, altsettings 0 and 1 */
322 	(struct usb_descriptor_header *) &ncm_data_nop_intf,
323 	(struct usb_descriptor_header *) &ncm_data_intf,
324 	(struct usb_descriptor_header *) &hs_ncm_in_desc,
325 	(struct usb_descriptor_header *) &hs_ncm_out_desc,
326 	NULL,
327 };
328 
329 
330 /* super speed support: */
331 
332 static struct usb_endpoint_descriptor ss_ncm_notify_desc = {
333 	.bLength =		USB_DT_ENDPOINT_SIZE,
334 	.bDescriptorType =	USB_DT_ENDPOINT,
335 
336 	.bEndpointAddress =	USB_DIR_IN,
337 	.bmAttributes =		USB_ENDPOINT_XFER_INT,
338 	.wMaxPacketSize =	cpu_to_le16(NCM_STATUS_BYTECOUNT),
339 	.bInterval =		USB_MS_TO_HS_INTERVAL(NCM_STATUS_INTERVAL_MS)
340 };
341 
342 static struct usb_ss_ep_comp_descriptor ss_ncm_notify_comp_desc = {
343 	.bLength =		sizeof(ss_ncm_notify_comp_desc),
344 	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
345 
346 	/* the following 3 values can be tweaked if necessary */
347 	/* .bMaxBurst =		0, */
348 	/* .bmAttributes =	0, */
349 	.wBytesPerInterval =	cpu_to_le16(NCM_STATUS_BYTECOUNT),
350 };
351 
352 static struct usb_endpoint_descriptor ss_ncm_in_desc = {
353 	.bLength =		USB_DT_ENDPOINT_SIZE,
354 	.bDescriptorType =	USB_DT_ENDPOINT,
355 
356 	.bEndpointAddress =	USB_DIR_IN,
357 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
358 	.wMaxPacketSize =	cpu_to_le16(1024),
359 };
360 
361 static struct usb_endpoint_descriptor ss_ncm_out_desc = {
362 	.bLength =		USB_DT_ENDPOINT_SIZE,
363 	.bDescriptorType =	USB_DT_ENDPOINT,
364 
365 	.bEndpointAddress =	USB_DIR_OUT,
366 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
367 	.wMaxPacketSize =	cpu_to_le16(1024),
368 };
369 
370 static struct usb_ss_ep_comp_descriptor ss_ncm_bulk_comp_desc = {
371 	.bLength =		sizeof(ss_ncm_bulk_comp_desc),
372 	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
373 
374 	/* the following 2 values can be tweaked if necessary */
375 	.bMaxBurst =		15,
376 	/* .bmAttributes =	0, */
377 };
378 
379 static struct usb_descriptor_header *ncm_ss_function[] = {
380 	(struct usb_descriptor_header *) &ncm_iad_desc,
381 	/* CDC NCM control descriptors */
382 	(struct usb_descriptor_header *) &ncm_control_intf,
383 	(struct usb_descriptor_header *) &ncm_header_desc,
384 	(struct usb_descriptor_header *) &ncm_union_desc,
385 	(struct usb_descriptor_header *) &ecm_desc,
386 	(struct usb_descriptor_header *) &ncm_desc,
387 	(struct usb_descriptor_header *) &ss_ncm_notify_desc,
388 	(struct usb_descriptor_header *) &ss_ncm_notify_comp_desc,
389 	/* data interface, altsettings 0 and 1 */
390 	(struct usb_descriptor_header *) &ncm_data_nop_intf,
391 	(struct usb_descriptor_header *) &ncm_data_intf,
392 	(struct usb_descriptor_header *) &ss_ncm_in_desc,
393 	(struct usb_descriptor_header *) &ss_ncm_bulk_comp_desc,
394 	(struct usb_descriptor_header *) &ss_ncm_out_desc,
395 	(struct usb_descriptor_header *) &ss_ncm_bulk_comp_desc,
396 	NULL,
397 };
398 
399 /* string descriptors: */
400 
401 #define STRING_CTRL_IDX	0
402 #define STRING_MAC_IDX	1
403 #define STRING_DATA_IDX	2
404 #define STRING_IAD_IDX	3
405 
406 static struct usb_string ncm_string_defs[] = {
407 	[STRING_CTRL_IDX].s = "CDC Network Control Model (NCM)",
408 	[STRING_MAC_IDX].s = "",
409 	[STRING_DATA_IDX].s = "CDC Network Data",
410 	[STRING_IAD_IDX].s = "CDC NCM",
411 	{  } /* end of list */
412 };
413 
414 static struct usb_gadget_strings ncm_string_table = {
415 	.language =		0x0409,	/* en-us */
416 	.strings =		ncm_string_defs,
417 };
418 
419 static struct usb_gadget_strings *ncm_strings[] = {
420 	&ncm_string_table,
421 	NULL,
422 };
423 
424 /*
425  * Here are options for NCM Datagram Pointer table (NDP) parser.
426  * There are 2 different formats: NDP16 and NDP32 in the spec (ch. 3),
427  * in NDP16 offsets and sizes fields are 1 16bit word wide,
428  * in NDP32 -- 2 16bit words wide. Also signatures are different.
429  * To make the parser code the same, put the differences in the structure,
430  * and switch pointers to the structures when the format is changed.
431  */
432 
433 struct ndp_parser_opts {
434 	u32		nth_sign;
435 	u32		ndp_sign;
436 	unsigned	nth_size;
437 	unsigned	ndp_size;
438 	unsigned	dpe_size;
439 	unsigned	ndplen_align;
440 	/* sizes in u16 units */
441 	unsigned	dgram_item_len; /* index or length */
442 	unsigned	block_length;
443 	unsigned	ndp_index;
444 	unsigned	reserved1;
445 	unsigned	reserved2;
446 	unsigned	next_ndp_index;
447 };
448 
449 static const struct ndp_parser_opts ndp16_opts = {
450 	.nth_sign = USB_CDC_NCM_NTH16_SIGN,
451 	.ndp_sign = USB_CDC_NCM_NDP16_NOCRC_SIGN,
452 	.nth_size = sizeof(struct usb_cdc_ncm_nth16),
453 	.ndp_size = sizeof(struct usb_cdc_ncm_ndp16),
454 	.dpe_size = sizeof(struct usb_cdc_ncm_dpe16),
455 	.ndplen_align = 4,
456 	.dgram_item_len = 1,
457 	.block_length = 1,
458 	.ndp_index = 1,
459 	.reserved1 = 0,
460 	.reserved2 = 0,
461 	.next_ndp_index = 1,
462 };
463 
464 static const struct ndp_parser_opts ndp32_opts = {
465 	.nth_sign = USB_CDC_NCM_NTH32_SIGN,
466 	.ndp_sign = USB_CDC_NCM_NDP32_NOCRC_SIGN,
467 	.nth_size = sizeof(struct usb_cdc_ncm_nth32),
468 	.ndp_size = sizeof(struct usb_cdc_ncm_ndp32),
469 	.dpe_size = sizeof(struct usb_cdc_ncm_dpe32),
470 	.ndplen_align = 8,
471 	.dgram_item_len = 2,
472 	.block_length = 2,
473 	.ndp_index = 2,
474 	.reserved1 = 1,
475 	.reserved2 = 2,
476 	.next_ndp_index = 2,
477 };
478 
479 static inline void put_ncm(__le16 **p, unsigned size, unsigned val)
480 {
481 	switch (size) {
482 	case 1:
483 		put_unaligned_le16((u16)val, *p);
484 		break;
485 	case 2:
486 		put_unaligned_le32((u32)val, *p);
487 
488 		break;
489 	default:
490 		BUG();
491 	}
492 
493 	*p += size;
494 }
495 
496 static inline unsigned get_ncm(__le16 **p, unsigned size)
497 {
498 	unsigned tmp;
499 
500 	switch (size) {
501 	case 1:
502 		tmp = get_unaligned_le16(*p);
503 		break;
504 	case 2:
505 		tmp = get_unaligned_le32(*p);
506 		break;
507 	default:
508 		BUG();
509 	}
510 
511 	*p += size;
512 	return tmp;
513 }
514 
515 /*-------------------------------------------------------------------------*/
516 
517 static inline void ncm_reset_values(struct f_ncm *ncm)
518 {
519 	ncm->parser_opts = &ndp16_opts;
520 	ncm->is_crc = false;
521 	ncm->ndp_sign = ncm->parser_opts->ndp_sign;
522 	ncm->port.cdc_filter = DEFAULT_FILTER;
523 
524 	/* doesn't make sense for ncm, fixed size used */
525 	ncm->port.header_len = 0;
526 
527 	ncm->port.fixed_out_len = le32_to_cpu(ntb_parameters.dwNtbOutMaxSize);
528 	ncm->port.fixed_in_len = NTB_DEFAULT_IN_SIZE;
529 }
530 
531 /*
532  * Context: ncm->lock held
533  */
534 static void ncm_do_notify(struct f_ncm *ncm)
535 {
536 	struct usb_request		*req = ncm->notify_req;
537 	struct usb_cdc_notification	*event;
538 	struct usb_composite_dev	*cdev = ncm->port.func.config->cdev;
539 	__le32				*data;
540 	int				status;
541 
542 	/* notification already in flight? */
543 	if (atomic_read(&ncm->notify_count))
544 		return;
545 
546 	event = req->buf;
547 	switch (ncm->notify_state) {
548 	case NCM_NOTIFY_NONE:
549 		return;
550 
551 	case NCM_NOTIFY_CONNECT:
552 		event->bNotificationType = USB_CDC_NOTIFY_NETWORK_CONNECTION;
553 		if (ncm->is_open)
554 			event->wValue = cpu_to_le16(1);
555 		else
556 			event->wValue = cpu_to_le16(0);
557 		event->wLength = 0;
558 		req->length = sizeof *event;
559 
560 		DBG(cdev, "notify connect %s\n",
561 				ncm->is_open ? "true" : "false");
562 		ncm->notify_state = NCM_NOTIFY_NONE;
563 		break;
564 
565 	case NCM_NOTIFY_SPEED:
566 		event->bNotificationType = USB_CDC_NOTIFY_SPEED_CHANGE;
567 		event->wValue = cpu_to_le16(0);
568 		event->wLength = cpu_to_le16(8);
569 		req->length = NCM_STATUS_BYTECOUNT;
570 
571 		/* SPEED_CHANGE data is up/down speeds in bits/sec */
572 		data = req->buf + sizeof *event;
573 		data[0] = cpu_to_le32(gether_bitrate(cdev->gadget));
574 		data[1] = data[0];
575 
576 		DBG(cdev, "notify speed %u\n", gether_bitrate(cdev->gadget));
577 		ncm->notify_state = NCM_NOTIFY_CONNECT;
578 		break;
579 	}
580 	event->bmRequestType = 0xA1;
581 	event->wIndex = cpu_to_le16(ncm->ctrl_id);
582 
583 	atomic_inc(&ncm->notify_count);
584 
585 	/*
586 	 * In double buffering if there is a space in FIFO,
587 	 * completion callback can be called right after the call,
588 	 * so unlocking
589 	 */
590 	spin_unlock(&ncm->lock);
591 	status = usb_ep_queue(ncm->notify, req, GFP_ATOMIC);
592 	spin_lock(&ncm->lock);
593 	if (status < 0) {
594 		atomic_dec(&ncm->notify_count);
595 		DBG(cdev, "notify --> %d\n", status);
596 	}
597 }
598 
599 /*
600  * Context: ncm->lock held
601  */
602 static void ncm_notify(struct f_ncm *ncm)
603 {
604 	/*
605 	 * NOTE on most versions of Linux, host side cdc-ethernet
606 	 * won't listen for notifications until its netdevice opens.
607 	 * The first notification then sits in the FIFO for a long
608 	 * time, and the second one is queued.
609 	 *
610 	 * If ncm_notify() is called before the second (CONNECT)
611 	 * notification is sent, then it will reset to send the SPEED
612 	 * notificaion again (and again, and again), but it's not a problem
613 	 */
614 	ncm->notify_state = NCM_NOTIFY_SPEED;
615 	ncm_do_notify(ncm);
616 }
617 
618 static void ncm_notify_complete(struct usb_ep *ep, struct usb_request *req)
619 {
620 	struct f_ncm			*ncm = req->context;
621 	struct usb_composite_dev	*cdev = ncm->port.func.config->cdev;
622 	struct usb_cdc_notification	*event = req->buf;
623 
624 	spin_lock(&ncm->lock);
625 	switch (req->status) {
626 	case 0:
627 		VDBG(cdev, "Notification %02x sent\n",
628 		     event->bNotificationType);
629 		atomic_dec(&ncm->notify_count);
630 		break;
631 	case -ECONNRESET:
632 	case -ESHUTDOWN:
633 		atomic_set(&ncm->notify_count, 0);
634 		ncm->notify_state = NCM_NOTIFY_NONE;
635 		break;
636 	default:
637 		DBG(cdev, "event %02x --> %d\n",
638 			event->bNotificationType, req->status);
639 		atomic_dec(&ncm->notify_count);
640 		break;
641 	}
642 	ncm_do_notify(ncm);
643 	spin_unlock(&ncm->lock);
644 }
645 
646 static void ncm_ep0out_complete(struct usb_ep *ep, struct usb_request *req)
647 {
648 	/* now for SET_NTB_INPUT_SIZE only */
649 	unsigned		in_size;
650 	struct usb_function	*f = req->context;
651 	struct f_ncm		*ncm = func_to_ncm(f);
652 	struct usb_composite_dev *cdev = f->config->cdev;
653 
654 	req->context = NULL;
655 	if (req->status || req->actual != req->length) {
656 		DBG(cdev, "Bad control-OUT transfer\n");
657 		goto invalid;
658 	}
659 
660 	in_size = get_unaligned_le32(req->buf);
661 	if (in_size < USB_CDC_NCM_NTB_MIN_IN_SIZE ||
662 	    in_size > le32_to_cpu(ntb_parameters.dwNtbInMaxSize)) {
663 		DBG(cdev, "Got wrong INPUT SIZE (%d) from host\n", in_size);
664 		goto invalid;
665 	}
666 
667 	ncm->port.fixed_in_len = in_size;
668 	VDBG(cdev, "Set NTB INPUT SIZE %d\n", in_size);
669 	return;
670 
671 invalid:
672 	usb_ep_set_halt(ep);
673 	return;
674 }
675 
676 static int ncm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
677 {
678 	struct f_ncm		*ncm = func_to_ncm(f);
679 	struct usb_composite_dev *cdev = f->config->cdev;
680 	struct usb_request	*req = cdev->req;
681 	int			value = -EOPNOTSUPP;
682 	u16			w_index = le16_to_cpu(ctrl->wIndex);
683 	u16			w_value = le16_to_cpu(ctrl->wValue);
684 	u16			w_length = le16_to_cpu(ctrl->wLength);
685 
686 	/*
687 	 * composite driver infrastructure handles everything except
688 	 * CDC class messages; interface activation uses set_alt().
689 	 */
690 	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
691 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
692 			| USB_CDC_SET_ETHERNET_PACKET_FILTER:
693 		/*
694 		 * see 6.2.30: no data, wIndex = interface,
695 		 * wValue = packet filter bitmap
696 		 */
697 		if (w_length != 0 || w_index != ncm->ctrl_id)
698 			goto invalid;
699 		DBG(cdev, "packet filter %02x\n", w_value);
700 		/*
701 		 * REVISIT locking of cdc_filter.  This assumes the UDC
702 		 * driver won't have a concurrent packet TX irq running on
703 		 * another CPU; or that if it does, this write is atomic...
704 		 */
705 		ncm->port.cdc_filter = w_value;
706 		value = 0;
707 		break;
708 	/*
709 	 * and optionally:
710 	 * case USB_CDC_SEND_ENCAPSULATED_COMMAND:
711 	 * case USB_CDC_GET_ENCAPSULATED_RESPONSE:
712 	 * case USB_CDC_SET_ETHERNET_MULTICAST_FILTERS:
713 	 * case USB_CDC_SET_ETHERNET_PM_PATTERN_FILTER:
714 	 * case USB_CDC_GET_ETHERNET_PM_PATTERN_FILTER:
715 	 * case USB_CDC_GET_ETHERNET_STATISTIC:
716 	 */
717 
718 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
719 		| USB_CDC_GET_NTB_PARAMETERS:
720 
721 		if (w_length == 0 || w_value != 0 || w_index != ncm->ctrl_id)
722 			goto invalid;
723 		value = w_length > sizeof ntb_parameters ?
724 			sizeof ntb_parameters : w_length;
725 		memcpy(req->buf, &ntb_parameters, value);
726 		VDBG(cdev, "Host asked NTB parameters\n");
727 		break;
728 
729 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
730 		| USB_CDC_GET_NTB_INPUT_SIZE:
731 
732 		if (w_length < 4 || w_value != 0 || w_index != ncm->ctrl_id)
733 			goto invalid;
734 		put_unaligned_le32(ncm->port.fixed_in_len, req->buf);
735 		value = 4;
736 		VDBG(cdev, "Host asked INPUT SIZE, sending %d\n",
737 		     ncm->port.fixed_in_len);
738 		break;
739 
740 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
741 		| USB_CDC_SET_NTB_INPUT_SIZE:
742 	{
743 		if (w_length != 4 || w_value != 0 || w_index != ncm->ctrl_id)
744 			goto invalid;
745 		req->complete = ncm_ep0out_complete;
746 		req->length = w_length;
747 		req->context = f;
748 
749 		value = req->length;
750 		break;
751 	}
752 
753 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
754 		| USB_CDC_GET_NTB_FORMAT:
755 	{
756 		uint16_t format;
757 
758 		if (w_length < 2 || w_value != 0 || w_index != ncm->ctrl_id)
759 			goto invalid;
760 		format = (ncm->parser_opts == &ndp16_opts) ? 0x0000 : 0x0001;
761 		put_unaligned_le16(format, req->buf);
762 		value = 2;
763 		VDBG(cdev, "Host asked NTB FORMAT, sending %d\n", format);
764 		break;
765 	}
766 
767 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
768 		| USB_CDC_SET_NTB_FORMAT:
769 	{
770 		if (w_length != 0 || w_index != ncm->ctrl_id)
771 			goto invalid;
772 		switch (w_value) {
773 		case 0x0000:
774 			ncm->parser_opts = &ndp16_opts;
775 			DBG(cdev, "NCM16 selected\n");
776 			break;
777 		case 0x0001:
778 			ncm->parser_opts = &ndp32_opts;
779 			DBG(cdev, "NCM32 selected\n");
780 			break;
781 		default:
782 			goto invalid;
783 		}
784 		value = 0;
785 		break;
786 	}
787 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
788 		| USB_CDC_GET_CRC_MODE:
789 	{
790 		uint16_t is_crc;
791 
792 		if (w_length < 2 || w_value != 0 || w_index != ncm->ctrl_id)
793 			goto invalid;
794 		is_crc = ncm->is_crc ? 0x0001 : 0x0000;
795 		put_unaligned_le16(is_crc, req->buf);
796 		value = 2;
797 		VDBG(cdev, "Host asked CRC MODE, sending %d\n", is_crc);
798 		break;
799 	}
800 
801 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
802 		| USB_CDC_SET_CRC_MODE:
803 	{
804 		if (w_length != 0 || w_index != ncm->ctrl_id)
805 			goto invalid;
806 		switch (w_value) {
807 		case 0x0000:
808 			ncm->is_crc = false;
809 			DBG(cdev, "non-CRC mode selected\n");
810 			break;
811 		case 0x0001:
812 			ncm->is_crc = true;
813 			DBG(cdev, "CRC mode selected\n");
814 			break;
815 		default:
816 			goto invalid;
817 		}
818 		value = 0;
819 		break;
820 	}
821 
822 	/* and disabled in ncm descriptor: */
823 	/* case USB_CDC_GET_NET_ADDRESS: */
824 	/* case USB_CDC_SET_NET_ADDRESS: */
825 	/* case USB_CDC_GET_MAX_DATAGRAM_SIZE: */
826 	/* case USB_CDC_SET_MAX_DATAGRAM_SIZE: */
827 
828 	default:
829 invalid:
830 		DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
831 			ctrl->bRequestType, ctrl->bRequest,
832 			w_value, w_index, w_length);
833 	}
834 	ncm->ndp_sign = ncm->parser_opts->ndp_sign |
835 		(ncm->is_crc ? NCM_NDP_HDR_CRC : 0);
836 
837 	/* respond with data transfer or status phase? */
838 	if (value >= 0) {
839 		DBG(cdev, "ncm req%02x.%02x v%04x i%04x l%d\n",
840 			ctrl->bRequestType, ctrl->bRequest,
841 			w_value, w_index, w_length);
842 		req->zero = 0;
843 		req->length = value;
844 		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
845 		if (value < 0)
846 			ERROR(cdev, "ncm req %02x.%02x response err %d\n",
847 					ctrl->bRequestType, ctrl->bRequest,
848 					value);
849 	}
850 
851 	/* device either stalls (value < 0) or reports success */
852 	return value;
853 }
854 
855 
856 static int ncm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
857 {
858 	struct f_ncm		*ncm = func_to_ncm(f);
859 	struct usb_composite_dev *cdev = f->config->cdev;
860 
861 	/* Control interface has only altsetting 0 */
862 	if (intf == ncm->ctrl_id) {
863 		if (alt != 0)
864 			goto fail;
865 
866 		DBG(cdev, "reset ncm control %d\n", intf);
867 		usb_ep_disable(ncm->notify);
868 
869 		if (!(ncm->notify->desc)) {
870 			DBG(cdev, "init ncm ctrl %d\n", intf);
871 			if (config_ep_by_speed(cdev->gadget, f, ncm->notify))
872 				goto fail;
873 		}
874 		usb_ep_enable(ncm->notify);
875 
876 	/* Data interface has two altsettings, 0 and 1 */
877 	} else if (intf == ncm->data_id) {
878 		if (alt > 1)
879 			goto fail;
880 
881 		if (ncm->port.in_ep->enabled) {
882 			DBG(cdev, "reset ncm\n");
883 			ncm->netdev = NULL;
884 			gether_disconnect(&ncm->port);
885 			ncm_reset_values(ncm);
886 		}
887 
888 		/*
889 		 * CDC Network only sends data in non-default altsettings.
890 		 * Changing altsettings resets filters, statistics, etc.
891 		 */
892 		if (alt == 1) {
893 			struct net_device	*net;
894 
895 			if (!ncm->port.in_ep->desc ||
896 			    !ncm->port.out_ep->desc) {
897 				DBG(cdev, "init ncm\n");
898 				if (config_ep_by_speed(cdev->gadget, f,
899 						       ncm->port.in_ep) ||
900 				    config_ep_by_speed(cdev->gadget, f,
901 						       ncm->port.out_ep)) {
902 					ncm->port.in_ep->desc = NULL;
903 					ncm->port.out_ep->desc = NULL;
904 					goto fail;
905 				}
906 			}
907 
908 			/* TODO */
909 			/* Enable zlps by default for NCM conformance;
910 			 * override for musb_hdrc (avoids txdma ovhead)
911 			 */
912 			ncm->port.is_zlp_ok =
913 				gadget_is_zlp_supported(cdev->gadget);
914 			ncm->port.cdc_filter = DEFAULT_FILTER;
915 			DBG(cdev, "activate ncm\n");
916 			net = gether_connect(&ncm->port);
917 			if (IS_ERR(net))
918 				return PTR_ERR(net);
919 			ncm->netdev = net;
920 		}
921 
922 		spin_lock(&ncm->lock);
923 		ncm_notify(ncm);
924 		spin_unlock(&ncm->lock);
925 	} else
926 		goto fail;
927 
928 	return 0;
929 fail:
930 	return -EINVAL;
931 }
932 
933 /*
934  * Because the data interface supports multiple altsettings,
935  * this NCM function *MUST* implement a get_alt() method.
936  */
937 static int ncm_get_alt(struct usb_function *f, unsigned intf)
938 {
939 	struct f_ncm		*ncm = func_to_ncm(f);
940 
941 	if (intf == ncm->ctrl_id)
942 		return 0;
943 	return ncm->port.in_ep->enabled ? 1 : 0;
944 }
945 
946 static struct sk_buff *package_for_tx(struct f_ncm *ncm)
947 {
948 	__le16		*ntb_iter;
949 	struct sk_buff	*skb2 = NULL;
950 	unsigned	ndp_pad;
951 	unsigned	ndp_index;
952 	unsigned	new_len;
953 
954 	const struct ndp_parser_opts *opts = ncm->parser_opts;
955 	const int ndp_align = le16_to_cpu(ntb_parameters.wNdpInAlignment);
956 	const int dgram_idx_len = 2 * 2 * opts->dgram_item_len;
957 
958 	/* Stop the timer */
959 	hrtimer_try_to_cancel(&ncm->task_timer);
960 
961 	ndp_pad = ALIGN(ncm->skb_tx_data->len, ndp_align) -
962 			ncm->skb_tx_data->len;
963 	ndp_index = ncm->skb_tx_data->len + ndp_pad;
964 	new_len = ndp_index + dgram_idx_len + ncm->skb_tx_ndp->len;
965 
966 	/* Set the final BlockLength and wNdpIndex */
967 	ntb_iter = (void *) ncm->skb_tx_data->data;
968 	/* Increment pointer to BlockLength */
969 	ntb_iter += 2 + 1 + 1;
970 	put_ncm(&ntb_iter, opts->block_length, new_len);
971 	put_ncm(&ntb_iter, opts->ndp_index, ndp_index);
972 
973 	/* Set the final NDP wLength */
974 	new_len = opts->ndp_size +
975 			(ncm->ndp_dgram_count * dgram_idx_len);
976 	ncm->ndp_dgram_count = 0;
977 	/* Increment from start to wLength */
978 	ntb_iter = (void *) ncm->skb_tx_ndp->data;
979 	ntb_iter += 2;
980 	put_unaligned_le16(new_len, ntb_iter);
981 
982 	/* Merge the skbs */
983 	swap(skb2, ncm->skb_tx_data);
984 	if (ncm->skb_tx_data) {
985 		dev_consume_skb_any(ncm->skb_tx_data);
986 		ncm->skb_tx_data = NULL;
987 	}
988 
989 	/* Insert NDP alignment. */
990 	skb_put_zero(skb2, ndp_pad);
991 
992 	/* Copy NTB across. */
993 	skb_put_data(skb2, ncm->skb_tx_ndp->data, ncm->skb_tx_ndp->len);
994 	dev_consume_skb_any(ncm->skb_tx_ndp);
995 	ncm->skb_tx_ndp = NULL;
996 
997 	/* Insert zero'd datagram. */
998 	skb_put_zero(skb2, dgram_idx_len);
999 
1000 	return skb2;
1001 }
1002 
1003 static struct sk_buff *ncm_wrap_ntb(struct gether *port,
1004 				    struct sk_buff *skb)
1005 {
1006 	struct f_ncm	*ncm = func_to_ncm(&port->func);
1007 	struct sk_buff	*skb2 = NULL;
1008 
1009 	if (skb) {
1010 		int		ncb_len = 0;
1011 		__le16		*ntb_data;
1012 		__le16		*ntb_ndp;
1013 		int		dgram_pad;
1014 
1015 		unsigned	max_size = ncm->port.fixed_in_len;
1016 		const struct ndp_parser_opts *opts = ncm->parser_opts;
1017 		const int ndp_align = le16_to_cpu(ntb_parameters.wNdpInAlignment);
1018 		const int div = le16_to_cpu(ntb_parameters.wNdpInDivisor);
1019 		const int rem = le16_to_cpu(ntb_parameters.wNdpInPayloadRemainder);
1020 		const int dgram_idx_len = 2 * 2 * opts->dgram_item_len;
1021 
1022 		/* Add the CRC if required up front */
1023 		if (ncm->is_crc) {
1024 			uint32_t	crc;
1025 			__le16		*crc_pos;
1026 
1027 			crc = ~crc32_le(~0,
1028 					skb->data,
1029 					skb->len);
1030 			crc_pos = skb_put(skb, sizeof(uint32_t));
1031 			put_unaligned_le32(crc, crc_pos);
1032 		}
1033 
1034 		/* If the new skb is too big for the current NCM NTB then
1035 		 * set the current stored skb to be sent now and clear it
1036 		 * ready for new data.
1037 		 * NOTE: Assume maximum align for speed of calculation.
1038 		 */
1039 		if (ncm->skb_tx_data
1040 		    && (ncm->ndp_dgram_count >= TX_MAX_NUM_DPE
1041 		    || (ncm->skb_tx_data->len +
1042 		    div + rem + skb->len +
1043 		    ncm->skb_tx_ndp->len + ndp_align + (2 * dgram_idx_len))
1044 		    > max_size)) {
1045 			skb2 = package_for_tx(ncm);
1046 			if (!skb2)
1047 				goto err;
1048 		}
1049 
1050 		if (!ncm->skb_tx_data) {
1051 			ncb_len = opts->nth_size;
1052 			dgram_pad = ALIGN(ncb_len, div) + rem - ncb_len;
1053 			ncb_len += dgram_pad;
1054 
1055 			/* Create a new skb for the NTH and datagrams. */
1056 			ncm->skb_tx_data = alloc_skb(max_size, GFP_ATOMIC);
1057 			if (!ncm->skb_tx_data)
1058 				goto err;
1059 
1060 			ncm->skb_tx_data->dev = ncm->netdev;
1061 			ntb_data = skb_put_zero(ncm->skb_tx_data, ncb_len);
1062 			/* dwSignature */
1063 			put_unaligned_le32(opts->nth_sign, ntb_data);
1064 			ntb_data += 2;
1065 			/* wHeaderLength */
1066 			put_unaligned_le16(opts->nth_size, ntb_data++);
1067 
1068 			/* Allocate an skb for storing the NDP,
1069 			 * TX_MAX_NUM_DPE should easily suffice for a
1070 			 * 16k packet.
1071 			 */
1072 			ncm->skb_tx_ndp = alloc_skb((int)(opts->ndp_size
1073 						    + opts->dpe_size
1074 						    * TX_MAX_NUM_DPE),
1075 						    GFP_ATOMIC);
1076 			if (!ncm->skb_tx_ndp)
1077 				goto err;
1078 
1079 			ncm->skb_tx_ndp->dev = ncm->netdev;
1080 			ntb_ndp = skb_put(ncm->skb_tx_ndp, opts->ndp_size);
1081 			memset(ntb_ndp, 0, ncb_len);
1082 			/* dwSignature */
1083 			put_unaligned_le32(ncm->ndp_sign, ntb_ndp);
1084 			ntb_ndp += 2;
1085 
1086 			/* There is always a zeroed entry */
1087 			ncm->ndp_dgram_count = 1;
1088 
1089 			/* Note: we skip opts->next_ndp_index */
1090 
1091 			/* Start the timer. */
1092 			hrtimer_start(&ncm->task_timer, TX_TIMEOUT_NSECS,
1093 				      HRTIMER_MODE_REL_SOFT);
1094 		}
1095 
1096 		/* Add the datagram position entries */
1097 		ntb_ndp = skb_put_zero(ncm->skb_tx_ndp, dgram_idx_len);
1098 
1099 		ncb_len = ncm->skb_tx_data->len;
1100 		dgram_pad = ALIGN(ncb_len, div) + rem - ncb_len;
1101 		ncb_len += dgram_pad;
1102 
1103 		/* (d)wDatagramIndex */
1104 		put_ncm(&ntb_ndp, opts->dgram_item_len, ncb_len);
1105 		/* (d)wDatagramLength */
1106 		put_ncm(&ntb_ndp, opts->dgram_item_len, skb->len);
1107 		ncm->ndp_dgram_count++;
1108 
1109 		/* Add the new data to the skb */
1110 		skb_put_zero(ncm->skb_tx_data, dgram_pad);
1111 		skb_put_data(ncm->skb_tx_data, skb->data, skb->len);
1112 		dev_consume_skb_any(skb);
1113 		skb = NULL;
1114 
1115 	} else if (ncm->skb_tx_data) {
1116 		/* If we get here ncm_wrap_ntb() was called with NULL skb,
1117 		 * because eth_start_xmit() was called with NULL skb by
1118 		 * ncm_tx_timeout() - hence, this is our signal to flush/send.
1119 		 */
1120 		skb2 = package_for_tx(ncm);
1121 		if (!skb2)
1122 			goto err;
1123 	}
1124 
1125 	return skb2;
1126 
1127 err:
1128 	ncm->netdev->stats.tx_dropped++;
1129 
1130 	if (skb)
1131 		dev_kfree_skb_any(skb);
1132 	if (ncm->skb_tx_data)
1133 		dev_kfree_skb_any(ncm->skb_tx_data);
1134 	if (ncm->skb_tx_ndp)
1135 		dev_kfree_skb_any(ncm->skb_tx_ndp);
1136 
1137 	return NULL;
1138 }
1139 
1140 /*
1141  * The transmit should only be run if no skb data has been sent
1142  * for a certain duration.
1143  */
1144 static enum hrtimer_restart ncm_tx_timeout(struct hrtimer *data)
1145 {
1146 	struct f_ncm *ncm = container_of(data, struct f_ncm, task_timer);
1147 	struct net_device *netdev = READ_ONCE(ncm->netdev);
1148 
1149 	if (netdev) {
1150 		/* XXX This allowance of a NULL skb argument to ndo_start_xmit
1151 		 * XXX is not sane.  The gadget layer should be redesigned so
1152 		 * XXX that the dev->wrap() invocations to build SKBs is transparent
1153 		 * XXX and performed in some way outside of the ndo_start_xmit
1154 		 * XXX interface.
1155 		 *
1156 		 * This will call directly into u_ether's eth_start_xmit()
1157 		 */
1158 		netdev->netdev_ops->ndo_start_xmit(NULL, netdev);
1159 	}
1160 	return HRTIMER_NORESTART;
1161 }
1162 
1163 static int ncm_unwrap_ntb(struct gether *port,
1164 			  struct sk_buff *skb,
1165 			  struct sk_buff_head *list)
1166 {
1167 	struct f_ncm	*ncm = func_to_ncm(&port->func);
1168 	unsigned char	*ntb_ptr = skb->data;
1169 	__le16		*tmp;
1170 	unsigned	index, index2;
1171 	int		ndp_index;
1172 	unsigned	dg_len, dg_len2;
1173 	unsigned	ndp_len;
1174 	unsigned	block_len;
1175 	struct sk_buff	*skb2;
1176 	int		ret = -EINVAL;
1177 	unsigned	ntb_max = le32_to_cpu(ntb_parameters.dwNtbOutMaxSize);
1178 	unsigned	frame_max;
1179 	const struct ndp_parser_opts *opts = ncm->parser_opts;
1180 	unsigned	crc_len = ncm->is_crc ? sizeof(uint32_t) : 0;
1181 	int		dgram_counter;
1182 	int		to_process = skb->len;
1183 	struct f_ncm_opts *ncm_opts;
1184 
1185 	ncm_opts = container_of(port->func.fi, struct f_ncm_opts, func_inst);
1186 	frame_max = ncm_opts->max_segment_size;
1187 
1188 parse_ntb:
1189 	tmp = (__le16 *)ntb_ptr;
1190 
1191 	/* dwSignature */
1192 	if (get_unaligned_le32(tmp) != opts->nth_sign) {
1193 		INFO(port->func.config->cdev, "Wrong NTH SIGN, skblen %d\n",
1194 			skb->len);
1195 		print_hex_dump(KERN_INFO, "HEAD:", DUMP_PREFIX_ADDRESS, 32, 1,
1196 			       skb->data, 32, false);
1197 
1198 		goto err;
1199 	}
1200 	tmp += 2;
1201 	/* wHeaderLength */
1202 	if (get_unaligned_le16(tmp++) != opts->nth_size) {
1203 		INFO(port->func.config->cdev, "Wrong NTB headersize\n");
1204 		goto err;
1205 	}
1206 	tmp++; /* skip wSequence */
1207 
1208 	block_len = get_ncm(&tmp, opts->block_length);
1209 	/* (d)wBlockLength */
1210 	if (block_len > ntb_max) {
1211 		INFO(port->func.config->cdev, "OUT size exceeded\n");
1212 		goto err;
1213 	}
1214 
1215 	ndp_index = get_ncm(&tmp, opts->ndp_index);
1216 
1217 	/* Run through all the NDP's in the NTB */
1218 	do {
1219 		/*
1220 		 * NCM 3.2
1221 		 * dwNdpIndex
1222 		 */
1223 		if (((ndp_index % 4) != 0) ||
1224 				(ndp_index < opts->nth_size) ||
1225 				(ndp_index > (block_len -
1226 					      opts->ndp_size))) {
1227 			INFO(port->func.config->cdev, "Bad index: %#X\n",
1228 			     ndp_index);
1229 			goto err;
1230 		}
1231 
1232 		/*
1233 		 * walk through NDP
1234 		 * dwSignature
1235 		 */
1236 		tmp = (__le16 *)(ntb_ptr + ndp_index);
1237 		if (get_unaligned_le32(tmp) != ncm->ndp_sign) {
1238 			INFO(port->func.config->cdev, "Wrong NDP SIGN\n");
1239 			goto err;
1240 		}
1241 		tmp += 2;
1242 
1243 		ndp_len = get_unaligned_le16(tmp++);
1244 		/*
1245 		 * NCM 3.3.1
1246 		 * wLength
1247 		 * entry is 2 items
1248 		 * item size is 16/32 bits, opts->dgram_item_len * 2 bytes
1249 		 * minimal: struct usb_cdc_ncm_ndpX + normal entry + zero entry
1250 		 * Each entry is a dgram index and a dgram length.
1251 		 */
1252 		if ((ndp_len < opts->ndp_size
1253 				+ 2 * 2 * (opts->dgram_item_len * 2)) ||
1254 				(ndp_len % opts->ndplen_align != 0)) {
1255 			INFO(port->func.config->cdev, "Bad NDP length: %#X\n",
1256 			     ndp_len);
1257 			goto err;
1258 		}
1259 		tmp += opts->reserved1;
1260 		/* Check for another NDP (d)wNextNdpIndex */
1261 		ndp_index = get_ncm(&tmp, opts->next_ndp_index);
1262 		tmp += opts->reserved2;
1263 
1264 		ndp_len -= opts->ndp_size;
1265 		index2 = get_ncm(&tmp, opts->dgram_item_len);
1266 		dg_len2 = get_ncm(&tmp, opts->dgram_item_len);
1267 		dgram_counter = 0;
1268 
1269 		do {
1270 			index = index2;
1271 			/* wDatagramIndex[0] */
1272 			if ((index < opts->nth_size) ||
1273 					(index > block_len - opts->dpe_size)) {
1274 				INFO(port->func.config->cdev,
1275 				     "Bad index: %#X\n", index);
1276 				goto err;
1277 			}
1278 
1279 			dg_len = dg_len2;
1280 			/*
1281 			 * wDatagramLength[0]
1282 			 * ethernet hdr + crc or larger than max frame size
1283 			 */
1284 			if ((dg_len < 14 + crc_len) ||
1285 					(dg_len > frame_max)) {
1286 				INFO(port->func.config->cdev,
1287 				     "Bad dgram length: %#X\n", dg_len);
1288 				goto err;
1289 			}
1290 			if (ncm->is_crc) {
1291 				uint32_t crc, crc2;
1292 
1293 				crc = get_unaligned_le32(ntb_ptr +
1294 							 index + dg_len -
1295 							 crc_len);
1296 				crc2 = ~crc32_le(~0,
1297 						 ntb_ptr + index,
1298 						 dg_len - crc_len);
1299 				if (crc != crc2) {
1300 					INFO(port->func.config->cdev,
1301 					     "Bad CRC\n");
1302 					goto err;
1303 				}
1304 			}
1305 
1306 			index2 = get_ncm(&tmp, opts->dgram_item_len);
1307 			dg_len2 = get_ncm(&tmp, opts->dgram_item_len);
1308 
1309 			/* wDatagramIndex[1] */
1310 			if (index2 > block_len - opts->dpe_size) {
1311 				INFO(port->func.config->cdev,
1312 				     "Bad index: %#X\n", index2);
1313 				goto err;
1314 			}
1315 
1316 			/*
1317 			 * Copy the data into a new skb.
1318 			 * This ensures the truesize is correct
1319 			 */
1320 			skb2 = netdev_alloc_skb_ip_align(ncm->netdev,
1321 							 dg_len - crc_len);
1322 			if (skb2 == NULL)
1323 				goto err;
1324 			skb_put_data(skb2, ntb_ptr + index,
1325 				     dg_len - crc_len);
1326 
1327 			skb_queue_tail(list, skb2);
1328 
1329 			ndp_len -= 2 * (opts->dgram_item_len * 2);
1330 
1331 			dgram_counter++;
1332 			if (index2 == 0 || dg_len2 == 0)
1333 				break;
1334 		} while (ndp_len > 2 * (opts->dgram_item_len * 2));
1335 	} while (ndp_index);
1336 
1337 	VDBG(port->func.config->cdev,
1338 	     "Parsed NTB with %d frames\n", dgram_counter);
1339 
1340 	to_process -= block_len;
1341 
1342 	/*
1343 	 * Windows NCM driver avoids USB ZLPs by adding a 1-byte
1344 	 * zero pad as needed.
1345 	 */
1346 	if (to_process == 1 &&
1347 	    (*(unsigned char *)(ntb_ptr + block_len) == 0x00)) {
1348 		to_process--;
1349 	} else if ((to_process > 0) && (block_len != 0)) {
1350 		ntb_ptr = (unsigned char *)(ntb_ptr + block_len);
1351 		goto parse_ntb;
1352 	}
1353 
1354 	dev_consume_skb_any(skb);
1355 
1356 	return 0;
1357 err:
1358 	skb_queue_purge(list);
1359 	dev_kfree_skb_any(skb);
1360 	return ret;
1361 }
1362 
1363 static void ncm_disable(struct usb_function *f)
1364 {
1365 	struct f_ncm		*ncm = func_to_ncm(f);
1366 	struct usb_composite_dev *cdev = f->config->cdev;
1367 
1368 	DBG(cdev, "ncm deactivated\n");
1369 
1370 	if (ncm->port.in_ep->enabled) {
1371 		ncm->netdev = NULL;
1372 		gether_disconnect(&ncm->port);
1373 	}
1374 
1375 	if (ncm->notify->enabled) {
1376 		usb_ep_disable(ncm->notify);
1377 		ncm->notify->desc = NULL;
1378 	}
1379 }
1380 
1381 /*-------------------------------------------------------------------------*/
1382 
1383 /*
1384  * Callbacks let us notify the host about connect/disconnect when the
1385  * net device is opened or closed.
1386  *
1387  * For testing, note that link states on this side include both opened
1388  * and closed variants of:
1389  *
1390  *   - disconnected/unconfigured
1391  *   - configured but inactive (data alt 0)
1392  *   - configured and active (data alt 1)
1393  *
1394  * Each needs to be tested with unplug, rmmod, SET_CONFIGURATION, and
1395  * SET_INTERFACE (altsetting).  Remember also that "configured" doesn't
1396  * imply the host is actually polling the notification endpoint, and
1397  * likewise that "active" doesn't imply it's actually using the data
1398  * endpoints for traffic.
1399  */
1400 
1401 static void ncm_open(struct gether *geth)
1402 {
1403 	struct f_ncm		*ncm = func_to_ncm(&geth->func);
1404 
1405 	DBG(ncm->port.func.config->cdev, "%s\n", __func__);
1406 
1407 	spin_lock(&ncm->lock);
1408 	ncm->is_open = true;
1409 	ncm_notify(ncm);
1410 	spin_unlock(&ncm->lock);
1411 }
1412 
1413 static void ncm_close(struct gether *geth)
1414 {
1415 	struct f_ncm		*ncm = func_to_ncm(&geth->func);
1416 
1417 	DBG(ncm->port.func.config->cdev, "%s\n", __func__);
1418 
1419 	spin_lock(&ncm->lock);
1420 	ncm->is_open = false;
1421 	ncm_notify(ncm);
1422 	spin_unlock(&ncm->lock);
1423 }
1424 
1425 /*-------------------------------------------------------------------------*/
1426 
1427 /* ethernet function driver setup/binding */
1428 
1429 static int ncm_bind(struct usb_configuration *c, struct usb_function *f)
1430 {
1431 	struct usb_composite_dev *cdev = c->cdev;
1432 	struct f_ncm		*ncm = func_to_ncm(f);
1433 	struct usb_string	*us;
1434 	int			status = 0;
1435 	struct usb_ep		*ep;
1436 	struct f_ncm_opts	*ncm_opts;
1437 
1438 	if (!can_support_ecm(cdev->gadget))
1439 		return -EINVAL;
1440 
1441 	ncm_opts = container_of(f->fi, struct f_ncm_opts, func_inst);
1442 
1443 	if (cdev->use_os_string) {
1444 		f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
1445 					   GFP_KERNEL);
1446 		if (!f->os_desc_table)
1447 			return -ENOMEM;
1448 		f->os_desc_n = 1;
1449 		f->os_desc_table[0].os_desc = &ncm_opts->ncm_os_desc;
1450 	}
1451 
1452 	mutex_lock(&ncm_opts->lock);
1453 	gether_set_gadget(ncm_opts->net, cdev->gadget);
1454 	if (!ncm_opts->bound) {
1455 		ncm_opts->net->mtu = (ncm_opts->max_segment_size - ETH_HLEN);
1456 		status = gether_register_netdev(ncm_opts->net);
1457 	}
1458 	mutex_unlock(&ncm_opts->lock);
1459 
1460 	if (status)
1461 		goto fail;
1462 
1463 	ncm_opts->bound = true;
1464 
1465 	us = usb_gstrings_attach(cdev, ncm_strings,
1466 				 ARRAY_SIZE(ncm_string_defs));
1467 	if (IS_ERR(us)) {
1468 		status = PTR_ERR(us);
1469 		goto fail;
1470 	}
1471 	ncm_control_intf.iInterface = us[STRING_CTRL_IDX].id;
1472 	ncm_data_nop_intf.iInterface = us[STRING_DATA_IDX].id;
1473 	ncm_data_intf.iInterface = us[STRING_DATA_IDX].id;
1474 	ecm_desc.iMACAddress = us[STRING_MAC_IDX].id;
1475 	ncm_iad_desc.iFunction = us[STRING_IAD_IDX].id;
1476 
1477 	/* allocate instance-specific interface IDs */
1478 	status = usb_interface_id(c, f);
1479 	if (status < 0)
1480 		goto fail;
1481 	ncm->ctrl_id = status;
1482 	ncm_iad_desc.bFirstInterface = status;
1483 
1484 	ncm_control_intf.bInterfaceNumber = status;
1485 	ncm_union_desc.bMasterInterface0 = status;
1486 
1487 	if (cdev->use_os_string)
1488 		f->os_desc_table[0].if_id =
1489 			ncm_iad_desc.bFirstInterface;
1490 
1491 	status = usb_interface_id(c, f);
1492 	if (status < 0)
1493 		goto fail;
1494 	ncm->data_id = status;
1495 
1496 	ncm_data_nop_intf.bInterfaceNumber = status;
1497 	ncm_data_intf.bInterfaceNumber = status;
1498 	ncm_union_desc.bSlaveInterface0 = status;
1499 
1500 	ecm_desc.wMaxSegmentSize = cpu_to_le16(ncm_opts->max_segment_size);
1501 
1502 	status = -ENODEV;
1503 
1504 	/* allocate instance-specific endpoints */
1505 	ep = usb_ep_autoconfig(cdev->gadget, &fs_ncm_in_desc);
1506 	if (!ep)
1507 		goto fail;
1508 	ncm->port.in_ep = ep;
1509 
1510 	ep = usb_ep_autoconfig(cdev->gadget, &fs_ncm_out_desc);
1511 	if (!ep)
1512 		goto fail;
1513 	ncm->port.out_ep = ep;
1514 
1515 	ep = usb_ep_autoconfig(cdev->gadget, &fs_ncm_notify_desc);
1516 	if (!ep)
1517 		goto fail;
1518 	ncm->notify = ep;
1519 
1520 	status = -ENOMEM;
1521 
1522 	/* allocate notification request and buffer */
1523 	ncm->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
1524 	if (!ncm->notify_req)
1525 		goto fail;
1526 	ncm->notify_req->buf = kmalloc(NCM_STATUS_BYTECOUNT, GFP_KERNEL);
1527 	if (!ncm->notify_req->buf)
1528 		goto fail;
1529 	ncm->notify_req->context = ncm;
1530 	ncm->notify_req->complete = ncm_notify_complete;
1531 
1532 	/*
1533 	 * support all relevant hardware speeds... we expect that when
1534 	 * hardware is dual speed, all bulk-capable endpoints work at
1535 	 * both speeds
1536 	 */
1537 	hs_ncm_in_desc.bEndpointAddress = fs_ncm_in_desc.bEndpointAddress;
1538 	hs_ncm_out_desc.bEndpointAddress = fs_ncm_out_desc.bEndpointAddress;
1539 	hs_ncm_notify_desc.bEndpointAddress =
1540 		fs_ncm_notify_desc.bEndpointAddress;
1541 
1542 	ss_ncm_in_desc.bEndpointAddress = fs_ncm_in_desc.bEndpointAddress;
1543 	ss_ncm_out_desc.bEndpointAddress = fs_ncm_out_desc.bEndpointAddress;
1544 	ss_ncm_notify_desc.bEndpointAddress =
1545 		fs_ncm_notify_desc.bEndpointAddress;
1546 
1547 	status = usb_assign_descriptors(f, ncm_fs_function, ncm_hs_function,
1548 			ncm_ss_function, ncm_ss_function);
1549 	if (status)
1550 		goto fail;
1551 
1552 	/*
1553 	 * NOTE:  all that is done without knowing or caring about
1554 	 * the network link ... which is unavailable to this code
1555 	 * until we're activated via set_alt().
1556 	 */
1557 
1558 	ncm->port.open = ncm_open;
1559 	ncm->port.close = ncm_close;
1560 
1561 	hrtimer_init(&ncm->task_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1562 	ncm->task_timer.function = ncm_tx_timeout;
1563 
1564 	DBG(cdev, "CDC Network: IN/%s OUT/%s NOTIFY/%s\n",
1565 			ncm->port.in_ep->name, ncm->port.out_ep->name,
1566 			ncm->notify->name);
1567 	return 0;
1568 
1569 fail:
1570 	kfree(f->os_desc_table);
1571 	f->os_desc_n = 0;
1572 
1573 	if (ncm->notify_req) {
1574 		kfree(ncm->notify_req->buf);
1575 		usb_ep_free_request(ncm->notify, ncm->notify_req);
1576 	}
1577 
1578 	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
1579 
1580 	return status;
1581 }
1582 
1583 static inline struct f_ncm_opts *to_f_ncm_opts(struct config_item *item)
1584 {
1585 	return container_of(to_config_group(item), struct f_ncm_opts,
1586 			    func_inst.group);
1587 }
1588 
1589 /* f_ncm_item_ops */
1590 USB_ETHERNET_CONFIGFS_ITEM(ncm);
1591 
1592 /* f_ncm_opts_dev_addr */
1593 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(ncm);
1594 
1595 /* f_ncm_opts_host_addr */
1596 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(ncm);
1597 
1598 /* f_ncm_opts_qmult */
1599 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(ncm);
1600 
1601 /* f_ncm_opts_ifname */
1602 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(ncm);
1603 
1604 static ssize_t ncm_opts_max_segment_size_show(struct config_item *item,
1605 					      char *page)
1606 {
1607 	struct f_ncm_opts *opts = to_f_ncm_opts(item);
1608 	u16 segment_size;
1609 
1610 	mutex_lock(&opts->lock);
1611 	segment_size = opts->max_segment_size;
1612 	mutex_unlock(&opts->lock);
1613 
1614 	return sysfs_emit(page, "%u\n", segment_size);
1615 }
1616 
1617 static ssize_t ncm_opts_max_segment_size_store(struct config_item *item,
1618 					       const char *page, size_t len)
1619 {
1620 	struct f_ncm_opts *opts = to_f_ncm_opts(item);
1621 	u16 segment_size;
1622 	int ret;
1623 
1624 	mutex_lock(&opts->lock);
1625 	if (opts->refcnt) {
1626 		ret = -EBUSY;
1627 		goto out;
1628 	}
1629 
1630 	ret = kstrtou16(page, 0, &segment_size);
1631 	if (ret)
1632 		goto out;
1633 
1634 	if (segment_size > MAX_DATAGRAM_SIZE) {
1635 		ret = -EINVAL;
1636 		goto out;
1637 	}
1638 
1639 	opts->max_segment_size = segment_size;
1640 	ret = len;
1641 out:
1642 	mutex_unlock(&opts->lock);
1643 	return ret;
1644 }
1645 
1646 CONFIGFS_ATTR(ncm_opts_, max_segment_size);
1647 
1648 static struct configfs_attribute *ncm_attrs[] = {
1649 	&ncm_opts_attr_dev_addr,
1650 	&ncm_opts_attr_host_addr,
1651 	&ncm_opts_attr_qmult,
1652 	&ncm_opts_attr_ifname,
1653 	&ncm_opts_attr_max_segment_size,
1654 	NULL,
1655 };
1656 
1657 static const struct config_item_type ncm_func_type = {
1658 	.ct_item_ops	= &ncm_item_ops,
1659 	.ct_attrs	= ncm_attrs,
1660 	.ct_owner	= THIS_MODULE,
1661 };
1662 
1663 static void ncm_free_inst(struct usb_function_instance *f)
1664 {
1665 	struct f_ncm_opts *opts;
1666 
1667 	opts = container_of(f, struct f_ncm_opts, func_inst);
1668 	if (opts->bound)
1669 		gether_cleanup(netdev_priv(opts->net));
1670 	else
1671 		free_netdev(opts->net);
1672 	kfree(opts->ncm_interf_group);
1673 	kfree(opts);
1674 }
1675 
1676 static struct usb_function_instance *ncm_alloc_inst(void)
1677 {
1678 	struct f_ncm_opts *opts;
1679 	struct usb_os_desc *descs[1];
1680 	char *names[1];
1681 	struct config_group *ncm_interf_group;
1682 
1683 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1684 	if (!opts)
1685 		return ERR_PTR(-ENOMEM);
1686 	opts->ncm_os_desc.ext_compat_id = opts->ncm_ext_compat_id;
1687 
1688 	mutex_init(&opts->lock);
1689 	opts->func_inst.free_func_inst = ncm_free_inst;
1690 	opts->net = gether_setup_default();
1691 	if (IS_ERR(opts->net)) {
1692 		struct net_device *net = opts->net;
1693 		kfree(opts);
1694 		return ERR_CAST(net);
1695 	}
1696 	opts->max_segment_size = ETH_FRAME_LEN;
1697 	INIT_LIST_HEAD(&opts->ncm_os_desc.ext_prop);
1698 
1699 	descs[0] = &opts->ncm_os_desc;
1700 	names[0] = "ncm";
1701 
1702 	config_group_init_type_name(&opts->func_inst.group, "", &ncm_func_type);
1703 	ncm_interf_group =
1704 		usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
1705 					       names, THIS_MODULE);
1706 	if (IS_ERR(ncm_interf_group)) {
1707 		ncm_free_inst(&opts->func_inst);
1708 		return ERR_CAST(ncm_interf_group);
1709 	}
1710 	opts->ncm_interf_group = ncm_interf_group;
1711 
1712 	return &opts->func_inst;
1713 }
1714 
1715 static void ncm_free(struct usb_function *f)
1716 {
1717 	struct f_ncm *ncm;
1718 	struct f_ncm_opts *opts;
1719 
1720 	ncm = func_to_ncm(f);
1721 	opts = container_of(f->fi, struct f_ncm_opts, func_inst);
1722 	kfree(ncm);
1723 	mutex_lock(&opts->lock);
1724 	opts->refcnt--;
1725 	mutex_unlock(&opts->lock);
1726 }
1727 
1728 static void ncm_unbind(struct usb_configuration *c, struct usb_function *f)
1729 {
1730 	struct f_ncm *ncm = func_to_ncm(f);
1731 
1732 	DBG(c->cdev, "ncm unbind\n");
1733 
1734 	hrtimer_cancel(&ncm->task_timer);
1735 
1736 	kfree(f->os_desc_table);
1737 	f->os_desc_n = 0;
1738 
1739 	ncm_string_defs[0].id = 0;
1740 	usb_free_all_descriptors(f);
1741 
1742 	if (atomic_read(&ncm->notify_count)) {
1743 		usb_ep_dequeue(ncm->notify, ncm->notify_req);
1744 		atomic_set(&ncm->notify_count, 0);
1745 	}
1746 
1747 	kfree(ncm->notify_req->buf);
1748 	usb_ep_free_request(ncm->notify, ncm->notify_req);
1749 }
1750 
1751 static struct usb_function *ncm_alloc(struct usb_function_instance *fi)
1752 {
1753 	struct f_ncm		*ncm;
1754 	struct f_ncm_opts	*opts;
1755 	int status;
1756 
1757 	/* allocate and initialize one new instance */
1758 	ncm = kzalloc(sizeof(*ncm), GFP_KERNEL);
1759 	if (!ncm)
1760 		return ERR_PTR(-ENOMEM);
1761 
1762 	opts = container_of(fi, struct f_ncm_opts, func_inst);
1763 	mutex_lock(&opts->lock);
1764 	opts->refcnt++;
1765 
1766 	/* export host's Ethernet address in CDC format */
1767 	status = gether_get_host_addr_cdc(opts->net, ncm->ethaddr,
1768 				      sizeof(ncm->ethaddr));
1769 	if (status < 12) { /* strlen("01234567890a") */
1770 		kfree(ncm);
1771 		mutex_unlock(&opts->lock);
1772 		return ERR_PTR(-EINVAL);
1773 	}
1774 	ncm_string_defs[STRING_MAC_IDX].s = ncm->ethaddr;
1775 
1776 	spin_lock_init(&ncm->lock);
1777 	ncm_reset_values(ncm);
1778 	ncm->port.ioport = netdev_priv(opts->net);
1779 	mutex_unlock(&opts->lock);
1780 	ncm->port.is_fixed = true;
1781 	ncm->port.supports_multi_frame = true;
1782 
1783 	ncm->port.func.name = "cdc_network";
1784 	/* descriptors are per-instance copies */
1785 	ncm->port.func.bind = ncm_bind;
1786 	ncm->port.func.unbind = ncm_unbind;
1787 	ncm->port.func.set_alt = ncm_set_alt;
1788 	ncm->port.func.get_alt = ncm_get_alt;
1789 	ncm->port.func.setup = ncm_setup;
1790 	ncm->port.func.disable = ncm_disable;
1791 	ncm->port.func.free_func = ncm_free;
1792 
1793 	ncm->port.wrap = ncm_wrap_ntb;
1794 	ncm->port.unwrap = ncm_unwrap_ntb;
1795 
1796 	return &ncm->port.func;
1797 }
1798 
1799 DECLARE_USB_FUNCTION_INIT(ncm, ncm_alloc_inst, ncm_alloc);
1800 MODULE_LICENSE("GPL");
1801 MODULE_AUTHOR("Yauheni Kaliuta");
1802