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