xref: /linux/drivers/net/usb/cdc_ncm.c (revision 23c48a124b469cee2eb0c75e6d22d366d1caa118)
1 /*
2  * cdc_ncm.c
3  *
4  * Copyright (C) ST-Ericsson 2010-2012
5  * Contact: Alexey Orishko <alexey.orishko@stericsson.com>
6  * Original author: Hans Petter Selasky <hans.petter.selasky@stericsson.com>
7  *
8  * USB Host Driver for Network Control Model (NCM)
9  * http://www.usb.org/developers/docs/devclass_docs/NCM10_012011.zip
10  *
11  * The NCM encoding, decoding and initialization logic
12  * derives from FreeBSD 8.x. if_cdce.c and if_cdcereg.h
13  *
14  * This software is available to you under a choice of one of two
15  * licenses. You may choose this file to be licensed under the terms
16  * of the GNU General Public License (GPL) Version 2 or the 2-clause
17  * BSD license listed below:
18  *
19  * Redistribution and use in source and binary forms, with or without
20  * modification, are permitted provided that the following conditions
21  * are met:
22  * 1. Redistributions of source code must retain the above copyright
23  *    notice, this list of conditions and the following disclaimer.
24  * 2. Redistributions in binary form must reproduce the above copyright
25  *    notice, this list of conditions and the following disclaimer in the
26  *    documentation and/or other materials provided with the distribution.
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38  * SUCH DAMAGE.
39  */
40 
41 #include <linux/module.h>
42 #include <linux/netdevice.h>
43 #include <linux/ctype.h>
44 #include <linux/etherdevice.h>
45 #include <linux/ethtool.h>
46 #include <linux/workqueue.h>
47 #include <linux/mii.h>
48 #include <linux/crc32.h>
49 #include <linux/usb.h>
50 #include <linux/hrtimer.h>
51 #include <linux/atomic.h>
52 #include <linux/usb/usbnet.h>
53 #include <linux/usb/cdc.h>
54 #include <linux/usb/cdc_ncm.h>
55 
56 #if IS_ENABLED(CONFIG_USB_NET_CDC_MBIM)
57 static bool prefer_mbim = true;
58 #else
59 static bool prefer_mbim;
60 #endif
61 module_param(prefer_mbim, bool, 0644);
62 MODULE_PARM_DESC(prefer_mbim, "Prefer MBIM setting on dual NCM/MBIM functions");
63 
64 static void cdc_ncm_txpath_bh(struct tasklet_struct *t);
65 static void cdc_ncm_tx_timeout_start(struct cdc_ncm_ctx *ctx);
66 static enum hrtimer_restart cdc_ncm_tx_timer_cb(struct hrtimer *hr_timer);
67 static struct usb_driver cdc_ncm_driver;
68 
69 struct cdc_ncm_stats {
70 	char stat_string[ETH_GSTRING_LEN];
71 	int sizeof_stat;
72 	int stat_offset;
73 };
74 
75 #define CDC_NCM_STAT(str, m) { \
76 		.stat_string = str, \
77 		.sizeof_stat = sizeof(((struct cdc_ncm_ctx *)0)->m), \
78 		.stat_offset = offsetof(struct cdc_ncm_ctx, m) }
79 #define CDC_NCM_SIMPLE_STAT(m)	CDC_NCM_STAT(__stringify(m), m)
80 
81 static const struct cdc_ncm_stats cdc_ncm_gstrings_stats[] = {
82 	CDC_NCM_SIMPLE_STAT(tx_reason_ntb_full),
83 	CDC_NCM_SIMPLE_STAT(tx_reason_ndp_full),
84 	CDC_NCM_SIMPLE_STAT(tx_reason_timeout),
85 	CDC_NCM_SIMPLE_STAT(tx_reason_max_datagram),
86 	CDC_NCM_SIMPLE_STAT(tx_overhead),
87 	CDC_NCM_SIMPLE_STAT(tx_ntbs),
88 	CDC_NCM_SIMPLE_STAT(rx_overhead),
89 	CDC_NCM_SIMPLE_STAT(rx_ntbs),
90 };
91 
92 #define CDC_NCM_LOW_MEM_MAX_CNT 10
93 
94 static int cdc_ncm_get_sset_count(struct net_device __always_unused *netdev, int sset)
95 {
96 	switch (sset) {
97 	case ETH_SS_STATS:
98 		return ARRAY_SIZE(cdc_ncm_gstrings_stats);
99 	default:
100 		return -EOPNOTSUPP;
101 	}
102 }
103 
104 static void cdc_ncm_get_ethtool_stats(struct net_device *netdev,
105 				    struct ethtool_stats __always_unused *stats,
106 				    u64 *data)
107 {
108 	struct usbnet *dev = netdev_priv(netdev);
109 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
110 	int i;
111 	char *p = NULL;
112 
113 	for (i = 0; i < ARRAY_SIZE(cdc_ncm_gstrings_stats); i++) {
114 		p = (char *)ctx + cdc_ncm_gstrings_stats[i].stat_offset;
115 		data[i] = (cdc_ncm_gstrings_stats[i].sizeof_stat == sizeof(u64)) ? *(u64 *)p : *(u32 *)p;
116 	}
117 }
118 
119 static void cdc_ncm_get_strings(struct net_device __always_unused *netdev, u32 stringset, u8 *data)
120 {
121 	u8 *p = data;
122 	int i;
123 
124 	switch (stringset) {
125 	case ETH_SS_STATS:
126 		for (i = 0; i < ARRAY_SIZE(cdc_ncm_gstrings_stats); i++) {
127 			memcpy(p, cdc_ncm_gstrings_stats[i].stat_string, ETH_GSTRING_LEN);
128 			p += ETH_GSTRING_LEN;
129 		}
130 	}
131 }
132 
133 static void cdc_ncm_update_rxtx_max(struct usbnet *dev, u32 new_rx, u32 new_tx);
134 
135 static const struct ethtool_ops cdc_ncm_ethtool_ops = {
136 	.get_link		= usbnet_get_link,
137 	.nway_reset		= usbnet_nway_reset,
138 	.get_drvinfo		= usbnet_get_drvinfo,
139 	.get_msglevel		= usbnet_get_msglevel,
140 	.set_msglevel		= usbnet_set_msglevel,
141 	.get_ts_info		= ethtool_op_get_ts_info,
142 	.get_sset_count		= cdc_ncm_get_sset_count,
143 	.get_strings		= cdc_ncm_get_strings,
144 	.get_ethtool_stats	= cdc_ncm_get_ethtool_stats,
145 	.get_link_ksettings	= usbnet_get_link_ksettings_internal,
146 	.set_link_ksettings	= NULL,
147 };
148 
149 static u32 cdc_ncm_check_rx_max(struct usbnet *dev, u32 new_rx)
150 {
151 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
152 	u32 val, max, min;
153 
154 	/* clamp new_rx to sane values */
155 	min = USB_CDC_NCM_NTB_MIN_IN_SIZE;
156 	max = min_t(u32, CDC_NCM_NTB_MAX_SIZE_RX, le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize));
157 
158 	/* dwNtbInMaxSize spec violation? Use MIN size for both limits */
159 	if (max < min) {
160 		dev_warn(&dev->intf->dev, "dwNtbInMaxSize=%u is too small. Using %u\n",
161 			 le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize), min);
162 		max = min;
163 	}
164 
165 	val = clamp_t(u32, new_rx, min, max);
166 	if (val != new_rx)
167 		dev_dbg(&dev->intf->dev, "rx_max must be in the [%u, %u] range\n", min, max);
168 
169 	return val;
170 }
171 
172 static u32 cdc_ncm_check_tx_max(struct usbnet *dev, u32 new_tx)
173 {
174 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
175 	u32 val, max, min;
176 
177 	/* clamp new_tx to sane values */
178 	if (ctx->is_ndp16)
179 		min = ctx->max_datagram_size + ctx->max_ndp_size + sizeof(struct usb_cdc_ncm_nth16);
180 	else
181 		min = ctx->max_datagram_size + ctx->max_ndp_size + sizeof(struct usb_cdc_ncm_nth32);
182 
183 	max = min_t(u32, CDC_NCM_NTB_MAX_SIZE_TX, le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize));
184 	if (max == 0)
185 		max = CDC_NCM_NTB_MAX_SIZE_TX; /* dwNtbOutMaxSize not set */
186 
187 	/* some devices set dwNtbOutMaxSize too low for the above default */
188 	min = min(min, max);
189 
190 	val = clamp_t(u32, new_tx, min, max);
191 	if (val != new_tx)
192 		dev_dbg(&dev->intf->dev, "tx_max must be in the [%u, %u] range\n", min, max);
193 
194 	return val;
195 }
196 
197 static ssize_t min_tx_pkt_show(struct device *d,
198 			       struct device_attribute *attr, char *buf)
199 {
200 	struct usbnet *dev = netdev_priv(to_net_dev(d));
201 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
202 
203 	return sprintf(buf, "%u\n", ctx->min_tx_pkt);
204 }
205 
206 static ssize_t rx_max_show(struct device *d,
207 			   struct device_attribute *attr, char *buf)
208 {
209 	struct usbnet *dev = netdev_priv(to_net_dev(d));
210 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
211 
212 	return sprintf(buf, "%u\n", ctx->rx_max);
213 }
214 
215 static ssize_t tx_max_show(struct device *d,
216 			   struct device_attribute *attr, char *buf)
217 {
218 	struct usbnet *dev = netdev_priv(to_net_dev(d));
219 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
220 
221 	return sprintf(buf, "%u\n", ctx->tx_max);
222 }
223 
224 static ssize_t tx_timer_usecs_show(struct device *d,
225 				   struct device_attribute *attr, char *buf)
226 {
227 	struct usbnet *dev = netdev_priv(to_net_dev(d));
228 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
229 
230 	return sprintf(buf, "%u\n", ctx->timer_interval / (u32)NSEC_PER_USEC);
231 }
232 
233 static ssize_t min_tx_pkt_store(struct device *d,
234 				struct device_attribute *attr,
235 				const char *buf, size_t len)
236 {
237 	struct usbnet *dev = netdev_priv(to_net_dev(d));
238 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
239 	unsigned long val;
240 
241 	/* no need to restrict values - anything from 0 to infinity is OK */
242 	if (kstrtoul(buf, 0, &val))
243 		return -EINVAL;
244 
245 	ctx->min_tx_pkt = val;
246 	return len;
247 }
248 
249 static ssize_t rx_max_store(struct device *d,
250 			    struct device_attribute *attr,
251 			    const char *buf, size_t len)
252 {
253 	struct usbnet *dev = netdev_priv(to_net_dev(d));
254 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
255 	unsigned long val;
256 
257 	if (kstrtoul(buf, 0, &val) || cdc_ncm_check_rx_max(dev, val) != val)
258 		return -EINVAL;
259 
260 	cdc_ncm_update_rxtx_max(dev, val, ctx->tx_max);
261 	return len;
262 }
263 
264 static ssize_t tx_max_store(struct device *d,
265 			    struct device_attribute *attr,
266 			    const char *buf, size_t len)
267 {
268 	struct usbnet *dev = netdev_priv(to_net_dev(d));
269 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
270 	unsigned long val;
271 
272 	if (kstrtoul(buf, 0, &val) || cdc_ncm_check_tx_max(dev, val) != val)
273 		return -EINVAL;
274 
275 	cdc_ncm_update_rxtx_max(dev, ctx->rx_max, val);
276 	return len;
277 }
278 
279 static ssize_t tx_timer_usecs_store(struct device *d,
280 				    struct device_attribute *attr,
281 				    const char *buf, size_t len)
282 {
283 	struct usbnet *dev = netdev_priv(to_net_dev(d));
284 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
285 	ssize_t ret;
286 	unsigned long val;
287 
288 	ret = kstrtoul(buf, 0, &val);
289 	if (ret)
290 		return ret;
291 	if (val && (val < CDC_NCM_TIMER_INTERVAL_MIN || val > CDC_NCM_TIMER_INTERVAL_MAX))
292 		return -EINVAL;
293 
294 	spin_lock_bh(&ctx->mtx);
295 	ctx->timer_interval = val * NSEC_PER_USEC;
296 	if (!ctx->timer_interval)
297 		ctx->tx_timer_pending = 0;
298 	spin_unlock_bh(&ctx->mtx);
299 	return len;
300 }
301 
302 static DEVICE_ATTR_RW(min_tx_pkt);
303 static DEVICE_ATTR_RW(rx_max);
304 static DEVICE_ATTR_RW(tx_max);
305 static DEVICE_ATTR_RW(tx_timer_usecs);
306 
307 static ssize_t ndp_to_end_show(struct device *d, struct device_attribute *attr, char *buf)
308 {
309 	struct usbnet *dev = netdev_priv(to_net_dev(d));
310 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
311 
312 	return sprintf(buf, "%c\n", ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END ? 'Y' : 'N');
313 }
314 
315 static ssize_t ndp_to_end_store(struct device *d,  struct device_attribute *attr, const char *buf, size_t len)
316 {
317 	struct usbnet *dev = netdev_priv(to_net_dev(d));
318 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
319 	bool enable;
320 
321 	if (strtobool(buf, &enable))
322 		return -EINVAL;
323 
324 	/* no change? */
325 	if (enable == (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))
326 		return len;
327 
328 	if (enable) {
329 		if (ctx->is_ndp16 && !ctx->delayed_ndp16) {
330 			ctx->delayed_ndp16 = kzalloc(ctx->max_ndp_size, GFP_KERNEL);
331 			if (!ctx->delayed_ndp16)
332 				return -ENOMEM;
333 		}
334 		if (!ctx->is_ndp16 && !ctx->delayed_ndp32) {
335 			ctx->delayed_ndp32 = kzalloc(ctx->max_ndp_size, GFP_KERNEL);
336 			if (!ctx->delayed_ndp32)
337 				return -ENOMEM;
338 		}
339 	}
340 
341 	/* flush pending data before changing flag */
342 	netif_tx_lock_bh(dev->net);
343 	usbnet_start_xmit(NULL, dev->net);
344 	spin_lock_bh(&ctx->mtx);
345 	if (enable)
346 		ctx->drvflags |= CDC_NCM_FLAG_NDP_TO_END;
347 	else
348 		ctx->drvflags &= ~CDC_NCM_FLAG_NDP_TO_END;
349 	spin_unlock_bh(&ctx->mtx);
350 	netif_tx_unlock_bh(dev->net);
351 
352 	return len;
353 }
354 static DEVICE_ATTR_RW(ndp_to_end);
355 
356 #define NCM_PARM_ATTR(name, format, tocpu)				\
357 static ssize_t cdc_ncm_show_##name(struct device *d, struct device_attribute *attr, char *buf) \
358 { \
359 	struct usbnet *dev = netdev_priv(to_net_dev(d)); \
360 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0]; \
361 	return sprintf(buf, format "\n", tocpu(ctx->ncm_parm.name));	\
362 } \
363 static DEVICE_ATTR(name, 0444, cdc_ncm_show_##name, NULL)
364 
365 NCM_PARM_ATTR(bmNtbFormatsSupported, "0x%04x", le16_to_cpu);
366 NCM_PARM_ATTR(dwNtbInMaxSize, "%u", le32_to_cpu);
367 NCM_PARM_ATTR(wNdpInDivisor, "%u", le16_to_cpu);
368 NCM_PARM_ATTR(wNdpInPayloadRemainder, "%u", le16_to_cpu);
369 NCM_PARM_ATTR(wNdpInAlignment, "%u", le16_to_cpu);
370 NCM_PARM_ATTR(dwNtbOutMaxSize, "%u", le32_to_cpu);
371 NCM_PARM_ATTR(wNdpOutDivisor, "%u", le16_to_cpu);
372 NCM_PARM_ATTR(wNdpOutPayloadRemainder, "%u", le16_to_cpu);
373 NCM_PARM_ATTR(wNdpOutAlignment, "%u", le16_to_cpu);
374 NCM_PARM_ATTR(wNtbOutMaxDatagrams, "%u", le16_to_cpu);
375 
376 static struct attribute *cdc_ncm_sysfs_attrs[] = {
377 	&dev_attr_min_tx_pkt.attr,
378 	&dev_attr_ndp_to_end.attr,
379 	&dev_attr_rx_max.attr,
380 	&dev_attr_tx_max.attr,
381 	&dev_attr_tx_timer_usecs.attr,
382 	&dev_attr_bmNtbFormatsSupported.attr,
383 	&dev_attr_dwNtbInMaxSize.attr,
384 	&dev_attr_wNdpInDivisor.attr,
385 	&dev_attr_wNdpInPayloadRemainder.attr,
386 	&dev_attr_wNdpInAlignment.attr,
387 	&dev_attr_dwNtbOutMaxSize.attr,
388 	&dev_attr_wNdpOutDivisor.attr,
389 	&dev_attr_wNdpOutPayloadRemainder.attr,
390 	&dev_attr_wNdpOutAlignment.attr,
391 	&dev_attr_wNtbOutMaxDatagrams.attr,
392 	NULL,
393 };
394 
395 static const struct attribute_group cdc_ncm_sysfs_attr_group = {
396 	.name = "cdc_ncm",
397 	.attrs = cdc_ncm_sysfs_attrs,
398 };
399 
400 /* handle rx_max and tx_max changes */
401 static void cdc_ncm_update_rxtx_max(struct usbnet *dev, u32 new_rx, u32 new_tx)
402 {
403 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
404 	u8 iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;
405 	u32 val;
406 
407 	val = cdc_ncm_check_rx_max(dev, new_rx);
408 
409 	/* inform device about NTB input size changes */
410 	if (val != ctx->rx_max) {
411 		__le32 dwNtbInMaxSize = cpu_to_le32(val);
412 
413 		dev_info(&dev->intf->dev, "setting rx_max = %u\n", val);
414 
415 		/* tell device to use new size */
416 		if (usbnet_write_cmd(dev, USB_CDC_SET_NTB_INPUT_SIZE,
417 				     USB_TYPE_CLASS | USB_DIR_OUT
418 				     | USB_RECIP_INTERFACE,
419 				     0, iface_no, &dwNtbInMaxSize, 4) < 0)
420 			dev_dbg(&dev->intf->dev, "Setting NTB Input Size failed\n");
421 		else
422 			ctx->rx_max = val;
423 	}
424 
425 	/* usbnet use these values for sizing rx queues */
426 	if (dev->rx_urb_size != ctx->rx_max) {
427 		dev->rx_urb_size = ctx->rx_max;
428 		if (netif_running(dev->net))
429 			usbnet_unlink_rx_urbs(dev);
430 	}
431 
432 	val = cdc_ncm_check_tx_max(dev, new_tx);
433 	if (val != ctx->tx_max)
434 		dev_info(&dev->intf->dev, "setting tx_max = %u\n", val);
435 
436 	/* Adding a pad byte here if necessary simplifies the handling
437 	 * in cdc_ncm_fill_tx_frame, making tx_max always represent
438 	 * the real skb max size.
439 	 *
440 	 * We cannot use dev->maxpacket here because this is called from
441 	 * .bind which is called before usbnet sets up dev->maxpacket
442 	 */
443 	if (val != le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize) &&
444 	    val % usb_maxpacket(dev->udev, dev->out) == 0)
445 		val++;
446 
447 	/* we might need to flush any pending tx buffers if running */
448 	if (netif_running(dev->net) && val > ctx->tx_max) {
449 		netif_tx_lock_bh(dev->net);
450 		usbnet_start_xmit(NULL, dev->net);
451 		/* make sure tx_curr_skb is reallocated if it was empty */
452 		if (ctx->tx_curr_skb) {
453 			dev_kfree_skb_any(ctx->tx_curr_skb);
454 			ctx->tx_curr_skb = NULL;
455 		}
456 		ctx->tx_max = val;
457 		netif_tx_unlock_bh(dev->net);
458 	} else {
459 		ctx->tx_max = val;
460 	}
461 
462 	dev->hard_mtu = ctx->tx_max;
463 
464 	/* max qlen depend on hard_mtu and rx_urb_size */
465 	usbnet_update_max_qlen(dev);
466 
467 	/* never pad more than 3 full USB packets per transfer */
468 	ctx->min_tx_pkt = clamp_t(u16, ctx->tx_max - 3 * usb_maxpacket(dev->udev, dev->out),
469 				  CDC_NCM_MIN_TX_PKT, ctx->tx_max);
470 }
471 
472 /* helpers for NCM and MBIM differences */
473 static u8 cdc_ncm_flags(struct usbnet *dev)
474 {
475 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
476 
477 	if (cdc_ncm_comm_intf_is_mbim(dev->intf->cur_altsetting) && ctx->mbim_desc)
478 		return ctx->mbim_desc->bmNetworkCapabilities;
479 	if (ctx->func_desc)
480 		return ctx->func_desc->bmNetworkCapabilities;
481 	return 0;
482 }
483 
484 static int cdc_ncm_eth_hlen(struct usbnet *dev)
485 {
486 	if (cdc_ncm_comm_intf_is_mbim(dev->intf->cur_altsetting))
487 		return 0;
488 	return ETH_HLEN;
489 }
490 
491 static u32 cdc_ncm_min_dgram_size(struct usbnet *dev)
492 {
493 	if (cdc_ncm_comm_intf_is_mbim(dev->intf->cur_altsetting))
494 		return CDC_MBIM_MIN_DATAGRAM_SIZE;
495 	return CDC_NCM_MIN_DATAGRAM_SIZE;
496 }
497 
498 static u32 cdc_ncm_max_dgram_size(struct usbnet *dev)
499 {
500 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
501 
502 	if (cdc_ncm_comm_intf_is_mbim(dev->intf->cur_altsetting) && ctx->mbim_desc)
503 		return le16_to_cpu(ctx->mbim_desc->wMaxSegmentSize);
504 	if (ctx->ether_desc)
505 		return le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);
506 	return CDC_NCM_MAX_DATAGRAM_SIZE;
507 }
508 
509 /* initial one-time device setup.  MUST be called with the data interface
510  * in altsetting 0
511  */
512 static int cdc_ncm_init(struct usbnet *dev)
513 {
514 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
515 	u8 iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;
516 	int err;
517 
518 	err = usbnet_read_cmd(dev, USB_CDC_GET_NTB_PARAMETERS,
519 			      USB_TYPE_CLASS | USB_DIR_IN
520 			      |USB_RECIP_INTERFACE,
521 			      0, iface_no, &ctx->ncm_parm,
522 			      sizeof(ctx->ncm_parm));
523 	if (err < 0) {
524 		dev_err(&dev->intf->dev, "failed GET_NTB_PARAMETERS\n");
525 		return err; /* GET_NTB_PARAMETERS is required */
526 	}
527 
528 	/* set CRC Mode */
529 	if (cdc_ncm_flags(dev) & USB_CDC_NCM_NCAP_CRC_MODE) {
530 		dev_dbg(&dev->intf->dev, "Setting CRC mode off\n");
531 		err = usbnet_write_cmd(dev, USB_CDC_SET_CRC_MODE,
532 				       USB_TYPE_CLASS | USB_DIR_OUT
533 				       | USB_RECIP_INTERFACE,
534 				       USB_CDC_NCM_CRC_NOT_APPENDED,
535 				       iface_no, NULL, 0);
536 		if (err < 0)
537 			dev_err(&dev->intf->dev, "SET_CRC_MODE failed\n");
538 	}
539 
540 	/* use ndp16 by default */
541 	ctx->is_ndp16 = 1;
542 
543 	/* set NTB format, if both formats are supported.
544 	 *
545 	 * "The host shall only send this command while the NCM Data
546 	 *  Interface is in alternate setting 0."
547 	 */
548 	if (le16_to_cpu(ctx->ncm_parm.bmNtbFormatsSupported) &
549 						USB_CDC_NCM_NTB32_SUPPORTED) {
550 		if (ctx->drvflags & CDC_NCM_FLAG_PREFER_NTB32) {
551 			ctx->is_ndp16 = 0;
552 			dev_dbg(&dev->intf->dev, "Setting NTB format to 32-bit\n");
553 			err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_FORMAT,
554 					       USB_TYPE_CLASS | USB_DIR_OUT
555 					       | USB_RECIP_INTERFACE,
556 					       USB_CDC_NCM_NTB32_FORMAT,
557 					       iface_no, NULL, 0);
558 		} else {
559 			ctx->is_ndp16 = 1;
560 			dev_dbg(&dev->intf->dev, "Setting NTB format to 16-bit\n");
561 			err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_FORMAT,
562 					       USB_TYPE_CLASS | USB_DIR_OUT
563 					       | USB_RECIP_INTERFACE,
564 					       USB_CDC_NCM_NTB16_FORMAT,
565 					       iface_no, NULL, 0);
566 		}
567 		if (err < 0) {
568 			ctx->is_ndp16 = 1;
569 			dev_err(&dev->intf->dev, "SET_NTB_FORMAT failed\n");
570 		}
571 	}
572 
573 	/* set initial device values */
574 	ctx->rx_max = le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize);
575 	ctx->tx_max = le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize);
576 	ctx->tx_remainder = le16_to_cpu(ctx->ncm_parm.wNdpOutPayloadRemainder);
577 	ctx->tx_modulus = le16_to_cpu(ctx->ncm_parm.wNdpOutDivisor);
578 	ctx->tx_ndp_modulus = le16_to_cpu(ctx->ncm_parm.wNdpOutAlignment);
579 	/* devices prior to NCM Errata shall set this field to zero */
580 	ctx->tx_max_datagrams = le16_to_cpu(ctx->ncm_parm.wNtbOutMaxDatagrams);
581 
582 	dev_dbg(&dev->intf->dev,
583 		"dwNtbInMaxSize=%u dwNtbOutMaxSize=%u wNdpOutPayloadRemainder=%u wNdpOutDivisor=%u wNdpOutAlignment=%u wNtbOutMaxDatagrams=%u flags=0x%x\n",
584 		ctx->rx_max, ctx->tx_max, ctx->tx_remainder, ctx->tx_modulus,
585 		ctx->tx_ndp_modulus, ctx->tx_max_datagrams, cdc_ncm_flags(dev));
586 
587 	/* max count of tx datagrams */
588 	if ((ctx->tx_max_datagrams == 0) ||
589 			(ctx->tx_max_datagrams > CDC_NCM_DPT_DATAGRAMS_MAX))
590 		ctx->tx_max_datagrams = CDC_NCM_DPT_DATAGRAMS_MAX;
591 
592 	/* set up maximum NDP size */
593 	if (ctx->is_ndp16)
594 		ctx->max_ndp_size = sizeof(struct usb_cdc_ncm_ndp16) + (ctx->tx_max_datagrams + 1) * sizeof(struct usb_cdc_ncm_dpe16);
595 	else
596 		ctx->max_ndp_size = sizeof(struct usb_cdc_ncm_ndp32) + (ctx->tx_max_datagrams + 1) * sizeof(struct usb_cdc_ncm_dpe32);
597 
598 	/* initial coalescing timer interval */
599 	ctx->timer_interval = CDC_NCM_TIMER_INTERVAL_USEC * NSEC_PER_USEC;
600 
601 	return 0;
602 }
603 
604 /* set a new max datagram size */
605 static void cdc_ncm_set_dgram_size(struct usbnet *dev, int new_size)
606 {
607 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
608 	u8 iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;
609 	__le16 max_datagram_size;
610 	u16 mbim_mtu;
611 	int err;
612 
613 	/* set default based on descriptors */
614 	ctx->max_datagram_size = clamp_t(u32, new_size,
615 					 cdc_ncm_min_dgram_size(dev),
616 					 CDC_NCM_MAX_DATAGRAM_SIZE);
617 
618 	/* inform the device about the selected Max Datagram Size? */
619 	if (!(cdc_ncm_flags(dev) & USB_CDC_NCM_NCAP_MAX_DATAGRAM_SIZE))
620 		goto out;
621 
622 	/* read current mtu value from device */
623 	err = usbnet_read_cmd(dev, USB_CDC_GET_MAX_DATAGRAM_SIZE,
624 			      USB_TYPE_CLASS | USB_DIR_IN | USB_RECIP_INTERFACE,
625 			      0, iface_no, &max_datagram_size, sizeof(max_datagram_size));
626 	if (err != sizeof(max_datagram_size)) {
627 		dev_dbg(&dev->intf->dev, "GET_MAX_DATAGRAM_SIZE failed\n");
628 		goto out;
629 	}
630 
631 	if (le16_to_cpu(max_datagram_size) == ctx->max_datagram_size)
632 		goto out;
633 
634 	max_datagram_size = cpu_to_le16(ctx->max_datagram_size);
635 	err = usbnet_write_cmd(dev, USB_CDC_SET_MAX_DATAGRAM_SIZE,
636 			       USB_TYPE_CLASS | USB_DIR_OUT | USB_RECIP_INTERFACE,
637 			       0, iface_no, &max_datagram_size, sizeof(max_datagram_size));
638 	if (err < 0)
639 		dev_dbg(&dev->intf->dev, "SET_MAX_DATAGRAM_SIZE failed\n");
640 
641 out:
642 	/* set MTU to max supported by the device if necessary */
643 	dev->net->mtu = min_t(int, dev->net->mtu, ctx->max_datagram_size - cdc_ncm_eth_hlen(dev));
644 
645 	/* do not exceed operator preferred MTU */
646 	if (ctx->mbim_extended_desc) {
647 		mbim_mtu = le16_to_cpu(ctx->mbim_extended_desc->wMTU);
648 		if (mbim_mtu != 0 && mbim_mtu < dev->net->mtu)
649 			dev->net->mtu = mbim_mtu;
650 	}
651 }
652 
653 static void cdc_ncm_fix_modulus(struct usbnet *dev)
654 {
655 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
656 	u32 val;
657 
658 	/*
659 	 * verify that the structure alignment is:
660 	 * - power of two
661 	 * - not greater than the maximum transmit length
662 	 * - not less than four bytes
663 	 */
664 	val = ctx->tx_ndp_modulus;
665 
666 	if ((val < USB_CDC_NCM_NDP_ALIGN_MIN_SIZE) ||
667 	    (val != ((-val) & val)) || (val >= ctx->tx_max)) {
668 		dev_dbg(&dev->intf->dev, "Using default alignment: 4 bytes\n");
669 		ctx->tx_ndp_modulus = USB_CDC_NCM_NDP_ALIGN_MIN_SIZE;
670 	}
671 
672 	/*
673 	 * verify that the payload alignment is:
674 	 * - power of two
675 	 * - not greater than the maximum transmit length
676 	 * - not less than four bytes
677 	 */
678 	val = ctx->tx_modulus;
679 
680 	if ((val < USB_CDC_NCM_NDP_ALIGN_MIN_SIZE) ||
681 	    (val != ((-val) & val)) || (val >= ctx->tx_max)) {
682 		dev_dbg(&dev->intf->dev, "Using default transmit modulus: 4 bytes\n");
683 		ctx->tx_modulus = USB_CDC_NCM_NDP_ALIGN_MIN_SIZE;
684 	}
685 
686 	/* verify the payload remainder */
687 	if (ctx->tx_remainder >= ctx->tx_modulus) {
688 		dev_dbg(&dev->intf->dev, "Using default transmit remainder: 0 bytes\n");
689 		ctx->tx_remainder = 0;
690 	}
691 
692 	/* adjust TX-remainder according to NCM specification. */
693 	ctx->tx_remainder = ((ctx->tx_remainder - cdc_ncm_eth_hlen(dev)) &
694 			     (ctx->tx_modulus - 1));
695 }
696 
697 static int cdc_ncm_setup(struct usbnet *dev)
698 {
699 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
700 	u32 def_rx, def_tx;
701 
702 	/* be conservative when selecting initial buffer size to
703 	 * increase the number of hosts this will work for
704 	 */
705 	def_rx = min_t(u32, CDC_NCM_NTB_DEF_SIZE_RX,
706 		       le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize));
707 	def_tx = min_t(u32, CDC_NCM_NTB_DEF_SIZE_TX,
708 		       le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize));
709 
710 	/* clamp rx_max and tx_max and inform device */
711 	cdc_ncm_update_rxtx_max(dev, def_rx, def_tx);
712 
713 	/* sanitize the modulus and remainder values */
714 	cdc_ncm_fix_modulus(dev);
715 
716 	/* set max datagram size */
717 	cdc_ncm_set_dgram_size(dev, cdc_ncm_max_dgram_size(dev));
718 	return 0;
719 }
720 
721 static void
722 cdc_ncm_find_endpoints(struct usbnet *dev, struct usb_interface *intf)
723 {
724 	struct usb_host_endpoint *e, *in = NULL, *out = NULL;
725 	u8 ep;
726 
727 	for (ep = 0; ep < intf->cur_altsetting->desc.bNumEndpoints; ep++) {
728 		e = intf->cur_altsetting->endpoint + ep;
729 
730 		/* ignore endpoints which cannot transfer data */
731 		if (!usb_endpoint_maxp(&e->desc))
732 			continue;
733 
734 		switch (e->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
735 		case USB_ENDPOINT_XFER_INT:
736 			if (usb_endpoint_dir_in(&e->desc)) {
737 				if (!dev->status)
738 					dev->status = e;
739 			}
740 			break;
741 
742 		case USB_ENDPOINT_XFER_BULK:
743 			if (usb_endpoint_dir_in(&e->desc)) {
744 				if (!in)
745 					in = e;
746 			} else {
747 				if (!out)
748 					out = e;
749 			}
750 			break;
751 
752 		default:
753 			break;
754 		}
755 	}
756 	if (in && !dev->in)
757 		dev->in = usb_rcvbulkpipe(dev->udev,
758 					  in->desc.bEndpointAddress &
759 					  USB_ENDPOINT_NUMBER_MASK);
760 	if (out && !dev->out)
761 		dev->out = usb_sndbulkpipe(dev->udev,
762 					   out->desc.bEndpointAddress &
763 					   USB_ENDPOINT_NUMBER_MASK);
764 }
765 
766 static void cdc_ncm_free(struct cdc_ncm_ctx *ctx)
767 {
768 	if (ctx == NULL)
769 		return;
770 
771 	if (ctx->tx_rem_skb != NULL) {
772 		dev_kfree_skb_any(ctx->tx_rem_skb);
773 		ctx->tx_rem_skb = NULL;
774 	}
775 
776 	if (ctx->tx_curr_skb != NULL) {
777 		dev_kfree_skb_any(ctx->tx_curr_skb);
778 		ctx->tx_curr_skb = NULL;
779 	}
780 
781 	if (ctx->is_ndp16)
782 		kfree(ctx->delayed_ndp16);
783 	else
784 		kfree(ctx->delayed_ndp32);
785 
786 	kfree(ctx);
787 }
788 
789 /* we need to override the usbnet change_mtu ndo for two reasons:
790  *  - respect the negotiated maximum datagram size
791  *  - avoid unwanted changes to rx and tx buffers
792  */
793 int cdc_ncm_change_mtu(struct net_device *net, int new_mtu)
794 {
795 	struct usbnet *dev = netdev_priv(net);
796 
797 	net->mtu = new_mtu;
798 	cdc_ncm_set_dgram_size(dev, new_mtu + cdc_ncm_eth_hlen(dev));
799 
800 	return 0;
801 }
802 EXPORT_SYMBOL_GPL(cdc_ncm_change_mtu);
803 
804 static const struct net_device_ops cdc_ncm_netdev_ops = {
805 	.ndo_open	     = usbnet_open,
806 	.ndo_stop	     = usbnet_stop,
807 	.ndo_start_xmit	     = usbnet_start_xmit,
808 	.ndo_tx_timeout	     = usbnet_tx_timeout,
809 	.ndo_set_rx_mode     = usbnet_set_rx_mode,
810 	.ndo_get_stats64     = dev_get_tstats64,
811 	.ndo_change_mtu	     = cdc_ncm_change_mtu,
812 	.ndo_set_mac_address = eth_mac_addr,
813 	.ndo_validate_addr   = eth_validate_addr,
814 };
815 
816 int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting, int drvflags)
817 {
818 	struct cdc_ncm_ctx *ctx;
819 	struct usb_driver *driver;
820 	u8 *buf;
821 	int len;
822 	int temp;
823 	u8 iface_no;
824 	struct usb_cdc_parsed_header hdr;
825 
826 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
827 	if (!ctx)
828 		return -ENOMEM;
829 
830 	ctx->dev = dev;
831 
832 	hrtimer_init(&ctx->tx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
833 	ctx->tx_timer.function = &cdc_ncm_tx_timer_cb;
834 	tasklet_setup(&ctx->bh, cdc_ncm_txpath_bh);
835 	atomic_set(&ctx->stop, 0);
836 	spin_lock_init(&ctx->mtx);
837 
838 	/* store ctx pointer in device data field */
839 	dev->data[0] = (unsigned long)ctx;
840 
841 	/* only the control interface can be successfully probed */
842 	ctx->control = intf;
843 
844 	/* get some pointers */
845 	driver = driver_of(intf);
846 	buf = intf->cur_altsetting->extra;
847 	len = intf->cur_altsetting->extralen;
848 
849 	/* parse through descriptors associated with control interface */
850 	cdc_parse_cdc_header(&hdr, intf, buf, len);
851 
852 	if (hdr.usb_cdc_union_desc)
853 		ctx->data = usb_ifnum_to_if(dev->udev,
854 					    hdr.usb_cdc_union_desc->bSlaveInterface0);
855 	ctx->ether_desc = hdr.usb_cdc_ether_desc;
856 	ctx->func_desc = hdr.usb_cdc_ncm_desc;
857 	ctx->mbim_desc = hdr.usb_cdc_mbim_desc;
858 	ctx->mbim_extended_desc = hdr.usb_cdc_mbim_extended_desc;
859 
860 	/* some buggy devices have an IAD but no CDC Union */
861 	if (!hdr.usb_cdc_union_desc && intf->intf_assoc && intf->intf_assoc->bInterfaceCount == 2) {
862 		ctx->data = usb_ifnum_to_if(dev->udev, intf->cur_altsetting->desc.bInterfaceNumber + 1);
863 		dev_dbg(&intf->dev, "CDC Union missing - got slave from IAD\n");
864 	}
865 
866 	/* check if we got everything */
867 	if (!ctx->data) {
868 		dev_err(&intf->dev, "CDC Union missing and no IAD found\n");
869 		goto error;
870 	}
871 	if (cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting)) {
872 		if (!ctx->mbim_desc) {
873 			dev_err(&intf->dev, "MBIM functional descriptor missing\n");
874 			goto error;
875 		}
876 	} else {
877 		if (!ctx->ether_desc || !ctx->func_desc) {
878 			dev_err(&intf->dev, "NCM or ECM functional descriptors missing\n");
879 			goto error;
880 		}
881 	}
882 
883 	/* claim data interface, if different from control */
884 	if (ctx->data != ctx->control) {
885 		temp = usb_driver_claim_interface(driver, ctx->data, dev);
886 		if (temp) {
887 			dev_err(&intf->dev, "failed to claim data intf\n");
888 			goto error;
889 		}
890 	}
891 
892 	iface_no = ctx->data->cur_altsetting->desc.bInterfaceNumber;
893 
894 	/* Device-specific flags */
895 	ctx->drvflags = drvflags;
896 
897 	/* Reset data interface. Some devices will not reset properly
898 	 * unless they are configured first.  Toggle the altsetting to
899 	 * force a reset.
900 	 * Some other devices do not work properly with this procedure
901 	 * that can be avoided using quirk CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE
902 	 */
903 	if (!(ctx->drvflags & CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE))
904 		usb_set_interface(dev->udev, iface_no, data_altsetting);
905 
906 	temp = usb_set_interface(dev->udev, iface_no, 0);
907 	if (temp) {
908 		dev_dbg(&intf->dev, "set interface failed\n");
909 		goto error2;
910 	}
911 
912 	/* initialize basic device settings */
913 	if (cdc_ncm_init(dev))
914 		goto error2;
915 
916 	/* Some firmwares need a pause here or they will silently fail
917 	 * to set up the interface properly.  This value was decided
918 	 * empirically on a Sierra Wireless MC7455 running 02.08.02.00
919 	 * firmware.
920 	 */
921 	usleep_range(10000, 20000);
922 
923 	/* configure data interface */
924 	temp = usb_set_interface(dev->udev, iface_no, data_altsetting);
925 	if (temp) {
926 		dev_dbg(&intf->dev, "set interface failed\n");
927 		goto error2;
928 	}
929 
930 	cdc_ncm_find_endpoints(dev, ctx->data);
931 	cdc_ncm_find_endpoints(dev, ctx->control);
932 	if (!dev->in || !dev->out || !dev->status) {
933 		dev_dbg(&intf->dev, "failed to collect endpoints\n");
934 		goto error2;
935 	}
936 
937 	usb_set_intfdata(ctx->control, dev);
938 
939 	if (ctx->ether_desc) {
940 		temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
941 		if (temp) {
942 			dev_err(&intf->dev, "failed to get mac address\n");
943 			goto error2;
944 		}
945 		dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net->dev_addr);
946 	}
947 
948 	/* finish setting up the device specific data */
949 	cdc_ncm_setup(dev);
950 
951 	/* Allocate the delayed NDP if needed. */
952 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
953 		if (ctx->is_ndp16) {
954 			ctx->delayed_ndp16 = kzalloc(ctx->max_ndp_size, GFP_KERNEL);
955 			if (!ctx->delayed_ndp16)
956 				goto error2;
957 		} else {
958 			ctx->delayed_ndp32 = kzalloc(ctx->max_ndp_size, GFP_KERNEL);
959 			if (!ctx->delayed_ndp32)
960 				goto error2;
961 		}
962 		dev_info(&intf->dev, "NDP will be placed at end of frame for this device.");
963 	}
964 
965 	/* override ethtool_ops */
966 	dev->net->ethtool_ops = &cdc_ncm_ethtool_ops;
967 
968 	/* add our sysfs attrs */
969 	dev->net->sysfs_groups[0] = &cdc_ncm_sysfs_attr_group;
970 
971 	/* must handle MTU changes */
972 	dev->net->netdev_ops = &cdc_ncm_netdev_ops;
973 	dev->net->max_mtu = cdc_ncm_max_dgram_size(dev) - cdc_ncm_eth_hlen(dev);
974 
975 	return 0;
976 
977 error2:
978 	usb_set_intfdata(ctx->control, NULL);
979 	usb_set_intfdata(ctx->data, NULL);
980 	if (ctx->data != ctx->control)
981 		usb_driver_release_interface(driver, ctx->data);
982 error:
983 	cdc_ncm_free((struct cdc_ncm_ctx *)dev->data[0]);
984 	dev->data[0] = 0;
985 	dev_info(&intf->dev, "bind() failure\n");
986 	return -ENODEV;
987 }
988 EXPORT_SYMBOL_GPL(cdc_ncm_bind_common);
989 
990 void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf)
991 {
992 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
993 	struct usb_driver *driver = driver_of(intf);
994 
995 	if (ctx == NULL)
996 		return;		/* no setup */
997 
998 	atomic_set(&ctx->stop, 1);
999 
1000 	hrtimer_cancel(&ctx->tx_timer);
1001 
1002 	tasklet_kill(&ctx->bh);
1003 
1004 	/* handle devices with combined control and data interface */
1005 	if (ctx->control == ctx->data)
1006 		ctx->data = NULL;
1007 
1008 	/* disconnect master --> disconnect slave */
1009 	if (intf == ctx->control && ctx->data) {
1010 		usb_set_intfdata(ctx->data, NULL);
1011 		usb_driver_release_interface(driver, ctx->data);
1012 		ctx->data = NULL;
1013 
1014 	} else if (intf == ctx->data && ctx->control) {
1015 		usb_set_intfdata(ctx->control, NULL);
1016 		usb_driver_release_interface(driver, ctx->control);
1017 		ctx->control = NULL;
1018 	}
1019 
1020 	usb_set_intfdata(intf, NULL);
1021 	cdc_ncm_free(ctx);
1022 }
1023 EXPORT_SYMBOL_GPL(cdc_ncm_unbind);
1024 
1025 /* Return the number of the MBIM control interface altsetting iff it
1026  * is preferred and available,
1027  */
1028 u8 cdc_ncm_select_altsetting(struct usb_interface *intf)
1029 {
1030 	struct usb_host_interface *alt;
1031 
1032 	/* The MBIM spec defines a NCM compatible default altsetting,
1033 	 * which we may have matched:
1034 	 *
1035 	 *  "Functions that implement both NCM 1.0 and MBIM (an
1036 	 *   “NCM/MBIM function”) according to this recommendation
1037 	 *   shall provide two alternate settings for the
1038 	 *   Communication Interface.  Alternate setting 0, and the
1039 	 *   associated class and endpoint descriptors, shall be
1040 	 *   constructed according to the rules given for the
1041 	 *   Communication Interface in section 5 of [USBNCM10].
1042 	 *   Alternate setting 1, and the associated class and
1043 	 *   endpoint descriptors, shall be constructed according to
1044 	 *   the rules given in section 6 (USB Device Model) of this
1045 	 *   specification."
1046 	 */
1047 	if (intf->num_altsetting < 2)
1048 		return intf->cur_altsetting->desc.bAlternateSetting;
1049 
1050 	if (prefer_mbim) {
1051 		alt = usb_altnum_to_altsetting(intf, CDC_NCM_COMM_ALTSETTING_MBIM);
1052 		if (alt && cdc_ncm_comm_intf_is_mbim(alt))
1053 			return CDC_NCM_COMM_ALTSETTING_MBIM;
1054 	}
1055 	return CDC_NCM_COMM_ALTSETTING_NCM;
1056 }
1057 EXPORT_SYMBOL_GPL(cdc_ncm_select_altsetting);
1058 
1059 static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
1060 {
1061 	/* MBIM backwards compatible function? */
1062 	if (cdc_ncm_select_altsetting(intf) != CDC_NCM_COMM_ALTSETTING_NCM)
1063 		return -ENODEV;
1064 
1065 	/* The NCM data altsetting is fixed, so we hard-coded it.
1066 	 * Additionally, generic NCM devices are assumed to accept arbitrarily
1067 	 * placed NDP.
1068 	 */
1069 	return cdc_ncm_bind_common(dev, intf, CDC_NCM_DATA_ALTSETTING_NCM, 0);
1070 }
1071 
1072 static void cdc_ncm_align_tail(struct sk_buff *skb, size_t modulus, size_t remainder, size_t max)
1073 {
1074 	size_t align = ALIGN(skb->len, modulus) - skb->len + remainder;
1075 
1076 	if (skb->len + align > max)
1077 		align = max - skb->len;
1078 	if (align && skb_tailroom(skb) >= align)
1079 		skb_put_zero(skb, align);
1080 }
1081 
1082 /* return a pointer to a valid struct usb_cdc_ncm_ndp16 of type sign, possibly
1083  * allocating a new one within skb
1084  */
1085 static struct usb_cdc_ncm_ndp16 *cdc_ncm_ndp16(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign, size_t reserve)
1086 {
1087 	struct usb_cdc_ncm_ndp16 *ndp16 = NULL;
1088 	struct usb_cdc_ncm_nth16 *nth16 = (void *)skb->data;
1089 	size_t ndpoffset = le16_to_cpu(nth16->wNdpIndex);
1090 
1091 	/* If NDP should be moved to the end of the NCM package, we can't follow the
1092 	* NTH16 header as we would normally do. NDP isn't written to the SKB yet, and
1093 	* the wNdpIndex field in the header is actually not consistent with reality. It will be later.
1094 	*/
1095 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
1096 		if (ctx->delayed_ndp16->dwSignature == sign)
1097 			return ctx->delayed_ndp16;
1098 
1099 		/* We can only push a single NDP to the end. Return
1100 		 * NULL to send what we've already got and queue this
1101 		 * skb for later.
1102 		 */
1103 		else if (ctx->delayed_ndp16->dwSignature)
1104 			return NULL;
1105 	}
1106 
1107 	/* follow the chain of NDPs, looking for a match */
1108 	while (ndpoffset) {
1109 		ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb->data + ndpoffset);
1110 		if  (ndp16->dwSignature == sign)
1111 			return ndp16;
1112 		ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
1113 	}
1114 
1115 	/* align new NDP */
1116 	if (!(ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))
1117 		cdc_ncm_align_tail(skb, ctx->tx_ndp_modulus, 0, ctx->tx_curr_size);
1118 
1119 	/* verify that there is room for the NDP and the datagram (reserve) */
1120 	if ((ctx->tx_curr_size - skb->len - reserve) < ctx->max_ndp_size)
1121 		return NULL;
1122 
1123 	/* link to it */
1124 	if (ndp16)
1125 		ndp16->wNextNdpIndex = cpu_to_le16(skb->len);
1126 	else
1127 		nth16->wNdpIndex = cpu_to_le16(skb->len);
1128 
1129 	/* push a new empty NDP */
1130 	if (!(ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))
1131 		ndp16 = skb_put_zero(skb, ctx->max_ndp_size);
1132 	else
1133 		ndp16 = ctx->delayed_ndp16;
1134 
1135 	ndp16->dwSignature = sign;
1136 	ndp16->wLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_ndp16) + sizeof(struct usb_cdc_ncm_dpe16));
1137 	return ndp16;
1138 }
1139 
1140 static struct usb_cdc_ncm_ndp32 *cdc_ncm_ndp32(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign, size_t reserve)
1141 {
1142 	struct usb_cdc_ncm_ndp32 *ndp32 = NULL;
1143 	struct usb_cdc_ncm_nth32 *nth32 = (void *)skb->data;
1144 	size_t ndpoffset = le32_to_cpu(nth32->dwNdpIndex);
1145 
1146 	/* If NDP should be moved to the end of the NCM package, we can't follow the
1147 	 * NTH32 header as we would normally do. NDP isn't written to the SKB yet, and
1148 	 * the wNdpIndex field in the header is actually not consistent with reality. It will be later.
1149 	 */
1150 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
1151 		if (ctx->delayed_ndp32->dwSignature == sign)
1152 			return ctx->delayed_ndp32;
1153 
1154 		/* We can only push a single NDP to the end. Return
1155 		 * NULL to send what we've already got and queue this
1156 		 * skb for later.
1157 		 */
1158 		else if (ctx->delayed_ndp32->dwSignature)
1159 			return NULL;
1160 	}
1161 
1162 	/* follow the chain of NDPs, looking for a match */
1163 	while (ndpoffset) {
1164 		ndp32 = (struct usb_cdc_ncm_ndp32 *)(skb->data + ndpoffset);
1165 		if  (ndp32->dwSignature == sign)
1166 			return ndp32;
1167 		ndpoffset = le32_to_cpu(ndp32->dwNextNdpIndex);
1168 	}
1169 
1170 	/* align new NDP */
1171 	if (!(ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))
1172 		cdc_ncm_align_tail(skb, ctx->tx_ndp_modulus, 0, ctx->tx_curr_size);
1173 
1174 	/* verify that there is room for the NDP and the datagram (reserve) */
1175 	if ((ctx->tx_curr_size - skb->len - reserve) < ctx->max_ndp_size)
1176 		return NULL;
1177 
1178 	/* link to it */
1179 	if (ndp32)
1180 		ndp32->dwNextNdpIndex = cpu_to_le32(skb->len);
1181 	else
1182 		nth32->dwNdpIndex = cpu_to_le32(skb->len);
1183 
1184 	/* push a new empty NDP */
1185 	if (!(ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))
1186 		ndp32 = skb_put_zero(skb, ctx->max_ndp_size);
1187 	else
1188 		ndp32 = ctx->delayed_ndp32;
1189 
1190 	ndp32->dwSignature = sign;
1191 	ndp32->wLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_ndp32) + sizeof(struct usb_cdc_ncm_dpe32));
1192 	return ndp32;
1193 }
1194 
1195 struct sk_buff *
1196 cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign)
1197 {
1198 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
1199 	union {
1200 		struct usb_cdc_ncm_nth16 *nth16;
1201 		struct usb_cdc_ncm_nth32 *nth32;
1202 	} nth;
1203 	union {
1204 		struct usb_cdc_ncm_ndp16 *ndp16;
1205 		struct usb_cdc_ncm_ndp32 *ndp32;
1206 	} ndp;
1207 	struct sk_buff *skb_out;
1208 	u16 n = 0, index, ndplen;
1209 	u8 ready2send = 0;
1210 	u32 delayed_ndp_size;
1211 	size_t padding_count;
1212 
1213 	/* When our NDP gets written in cdc_ncm_ndp(), then skb_out->len gets updated
1214 	 * accordingly. Otherwise, we should check here.
1215 	 */
1216 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END)
1217 		delayed_ndp_size = ctx->max_ndp_size +
1218 			max_t(u32,
1219 			      ctx->tx_ndp_modulus,
1220 			      ctx->tx_modulus + ctx->tx_remainder) - 1;
1221 	else
1222 		delayed_ndp_size = 0;
1223 
1224 	/* if there is a remaining skb, it gets priority */
1225 	if (skb != NULL) {
1226 		swap(skb, ctx->tx_rem_skb);
1227 		swap(sign, ctx->tx_rem_sign);
1228 	} else {
1229 		ready2send = 1;
1230 	}
1231 
1232 	/* check if we are resuming an OUT skb */
1233 	skb_out = ctx->tx_curr_skb;
1234 
1235 	/* allocate a new OUT skb */
1236 	if (!skb_out) {
1237 		if (ctx->tx_low_mem_val == 0) {
1238 			ctx->tx_curr_size = ctx->tx_max;
1239 			skb_out = alloc_skb(ctx->tx_curr_size, GFP_ATOMIC);
1240 			/* If the memory allocation fails we will wait longer
1241 			 * each time before attempting another full size
1242 			 * allocation again to not overload the system
1243 			 * further.
1244 			 */
1245 			if (skb_out == NULL) {
1246 				ctx->tx_low_mem_max_cnt = min(ctx->tx_low_mem_max_cnt + 1,
1247 							      (unsigned)CDC_NCM_LOW_MEM_MAX_CNT);
1248 				ctx->tx_low_mem_val = ctx->tx_low_mem_max_cnt;
1249 			}
1250 		}
1251 		if (skb_out == NULL) {
1252 			/* See if a very small allocation is possible.
1253 			 * We will send this packet immediately and hope
1254 			 * that there is more memory available later.
1255 			 */
1256 			if (skb)
1257 				ctx->tx_curr_size = max(skb->len,
1258 					(u32)USB_CDC_NCM_NTB_MIN_OUT_SIZE);
1259 			else
1260 				ctx->tx_curr_size = USB_CDC_NCM_NTB_MIN_OUT_SIZE;
1261 			skb_out = alloc_skb(ctx->tx_curr_size, GFP_ATOMIC);
1262 
1263 			/* No allocation possible so we will abort */
1264 			if (skb_out == NULL) {
1265 				if (skb != NULL) {
1266 					dev_kfree_skb_any(skb);
1267 					dev->net->stats.tx_dropped++;
1268 				}
1269 				goto exit_no_skb;
1270 			}
1271 			ctx->tx_low_mem_val--;
1272 		}
1273 		if (ctx->is_ndp16) {
1274 			/* fill out the initial 16-bit NTB header */
1275 			nth.nth16 = skb_put_zero(skb_out, sizeof(struct usb_cdc_ncm_nth16));
1276 			nth.nth16->dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN);
1277 			nth.nth16->wHeaderLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16));
1278 			nth.nth16->wSequence = cpu_to_le16(ctx->tx_seq++);
1279 		} else {
1280 			/* fill out the initial 32-bit NTB header */
1281 			nth.nth32 = skb_put_zero(skb_out, sizeof(struct usb_cdc_ncm_nth32));
1282 			nth.nth32->dwSignature = cpu_to_le32(USB_CDC_NCM_NTH32_SIGN);
1283 			nth.nth32->wHeaderLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_nth32));
1284 			nth.nth32->wSequence = cpu_to_le16(ctx->tx_seq++);
1285 		}
1286 
1287 		/* count total number of frames in this NTB */
1288 		ctx->tx_curr_frame_num = 0;
1289 
1290 		/* recent payload counter for this skb_out */
1291 		ctx->tx_curr_frame_payload = 0;
1292 	}
1293 
1294 	for (n = ctx->tx_curr_frame_num; n < ctx->tx_max_datagrams; n++) {
1295 		/* send any remaining skb first */
1296 		if (skb == NULL) {
1297 			skb = ctx->tx_rem_skb;
1298 			sign = ctx->tx_rem_sign;
1299 			ctx->tx_rem_skb = NULL;
1300 
1301 			/* check for end of skb */
1302 			if (skb == NULL)
1303 				break;
1304 		}
1305 
1306 		/* get the appropriate NDP for this skb */
1307 		if (ctx->is_ndp16)
1308 			ndp.ndp16 = cdc_ncm_ndp16(ctx, skb_out, sign, skb->len + ctx->tx_modulus + ctx->tx_remainder);
1309 		else
1310 			ndp.ndp32 = cdc_ncm_ndp32(ctx, skb_out, sign, skb->len + ctx->tx_modulus + ctx->tx_remainder);
1311 
1312 		/* align beginning of next frame */
1313 		cdc_ncm_align_tail(skb_out,  ctx->tx_modulus, ctx->tx_remainder, ctx->tx_curr_size);
1314 
1315 		/* check if we had enough room left for both NDP and frame */
1316 		if ((ctx->is_ndp16 && !ndp.ndp16) || (!ctx->is_ndp16 && !ndp.ndp32) ||
1317 		    skb_out->len + skb->len + delayed_ndp_size > ctx->tx_curr_size) {
1318 			if (n == 0) {
1319 				/* won't fit, MTU problem? */
1320 				dev_kfree_skb_any(skb);
1321 				skb = NULL;
1322 				dev->net->stats.tx_dropped++;
1323 			} else {
1324 				/* no room for skb - store for later */
1325 				if (ctx->tx_rem_skb != NULL) {
1326 					dev_kfree_skb_any(ctx->tx_rem_skb);
1327 					dev->net->stats.tx_dropped++;
1328 				}
1329 				ctx->tx_rem_skb = skb;
1330 				ctx->tx_rem_sign = sign;
1331 				skb = NULL;
1332 				ready2send = 1;
1333 				ctx->tx_reason_ntb_full++;	/* count reason for transmitting */
1334 			}
1335 			break;
1336 		}
1337 
1338 		/* calculate frame number within this NDP */
1339 		if (ctx->is_ndp16) {
1340 			ndplen = le16_to_cpu(ndp.ndp16->wLength);
1341 			index = (ndplen - sizeof(struct usb_cdc_ncm_ndp16)) / sizeof(struct usb_cdc_ncm_dpe16) - 1;
1342 
1343 			/* OK, add this skb */
1344 			ndp.ndp16->dpe16[index].wDatagramLength = cpu_to_le16(skb->len);
1345 			ndp.ndp16->dpe16[index].wDatagramIndex = cpu_to_le16(skb_out->len);
1346 			ndp.ndp16->wLength = cpu_to_le16(ndplen + sizeof(struct usb_cdc_ncm_dpe16));
1347 		} else {
1348 			ndplen = le16_to_cpu(ndp.ndp32->wLength);
1349 			index = (ndplen - sizeof(struct usb_cdc_ncm_ndp32)) / sizeof(struct usb_cdc_ncm_dpe32) - 1;
1350 
1351 			ndp.ndp32->dpe32[index].dwDatagramLength = cpu_to_le32(skb->len);
1352 			ndp.ndp32->dpe32[index].dwDatagramIndex = cpu_to_le32(skb_out->len);
1353 			ndp.ndp32->wLength = cpu_to_le16(ndplen + sizeof(struct usb_cdc_ncm_dpe32));
1354 		}
1355 		skb_put_data(skb_out, skb->data, skb->len);
1356 		ctx->tx_curr_frame_payload += skb->len;	/* count real tx payload data */
1357 		dev_kfree_skb_any(skb);
1358 		skb = NULL;
1359 
1360 		/* send now if this NDP is full */
1361 		if (index >= CDC_NCM_DPT_DATAGRAMS_MAX) {
1362 			ready2send = 1;
1363 			ctx->tx_reason_ndp_full++;	/* count reason for transmitting */
1364 			break;
1365 		}
1366 	}
1367 
1368 	/* free up any dangling skb */
1369 	if (skb != NULL) {
1370 		dev_kfree_skb_any(skb);
1371 		skb = NULL;
1372 		dev->net->stats.tx_dropped++;
1373 	}
1374 
1375 	ctx->tx_curr_frame_num = n;
1376 
1377 	if (n == 0) {
1378 		/* wait for more frames */
1379 		/* push variables */
1380 		ctx->tx_curr_skb = skb_out;
1381 		goto exit_no_skb;
1382 
1383 	} else if ((n < ctx->tx_max_datagrams) && (ready2send == 0) && (ctx->timer_interval > 0)) {
1384 		/* wait for more frames */
1385 		/* push variables */
1386 		ctx->tx_curr_skb = skb_out;
1387 		/* set the pending count */
1388 		if (n < CDC_NCM_RESTART_TIMER_DATAGRAM_CNT)
1389 			ctx->tx_timer_pending = CDC_NCM_TIMER_PENDING_CNT;
1390 		goto exit_no_skb;
1391 
1392 	} else {
1393 		if (n == ctx->tx_max_datagrams)
1394 			ctx->tx_reason_max_datagram++;	/* count reason for transmitting */
1395 		/* frame goes out */
1396 		/* variables will be reset at next call */
1397 	}
1398 
1399 	/* If requested, put NDP at end of frame. */
1400 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
1401 		if (ctx->is_ndp16) {
1402 			nth.nth16 = (struct usb_cdc_ncm_nth16 *)skb_out->data;
1403 			cdc_ncm_align_tail(skb_out, ctx->tx_ndp_modulus, 0, ctx->tx_curr_size - ctx->max_ndp_size);
1404 			nth.nth16->wNdpIndex = cpu_to_le16(skb_out->len);
1405 			skb_put_data(skb_out, ctx->delayed_ndp16, ctx->max_ndp_size);
1406 
1407 			/* Zero out delayed NDP - signature checking will naturally fail. */
1408 			ndp.ndp16 = memset(ctx->delayed_ndp16, 0, ctx->max_ndp_size);
1409 		} else {
1410 			nth.nth32 = (struct usb_cdc_ncm_nth32 *)skb_out->data;
1411 			cdc_ncm_align_tail(skb_out, ctx->tx_ndp_modulus, 0, ctx->tx_curr_size - ctx->max_ndp_size);
1412 			nth.nth32->dwNdpIndex = cpu_to_le32(skb_out->len);
1413 			skb_put_data(skb_out, ctx->delayed_ndp32, ctx->max_ndp_size);
1414 
1415 			ndp.ndp32 = memset(ctx->delayed_ndp32, 0, ctx->max_ndp_size);
1416 		}
1417 	}
1418 
1419 	/* If collected data size is less or equal ctx->min_tx_pkt
1420 	 * bytes, we send buffers as it is. If we get more data, it
1421 	 * would be more efficient for USB HS mobile device with DMA
1422 	 * engine to receive a full size NTB, than canceling DMA
1423 	 * transfer and receiving a short packet.
1424 	 *
1425 	 * This optimization support is pointless if we end up sending
1426 	 * a ZLP after full sized NTBs.
1427 	 */
1428 	if (!(dev->driver_info->flags & FLAG_SEND_ZLP) &&
1429 	    skb_out->len > ctx->min_tx_pkt) {
1430 		padding_count = ctx->tx_curr_size - skb_out->len;
1431 		if (!WARN_ON(padding_count > ctx->tx_curr_size))
1432 			skb_put_zero(skb_out, padding_count);
1433 	} else if (skb_out->len < ctx->tx_curr_size &&
1434 		   (skb_out->len % dev->maxpacket) == 0) {
1435 		skb_put_u8(skb_out, 0);	/* force short packet */
1436 	}
1437 
1438 	/* set final frame length */
1439 	if (ctx->is_ndp16) {
1440 		nth.nth16 = (struct usb_cdc_ncm_nth16 *)skb_out->data;
1441 		nth.nth16->wBlockLength = cpu_to_le16(skb_out->len);
1442 	} else {
1443 		nth.nth32 = (struct usb_cdc_ncm_nth32 *)skb_out->data;
1444 		nth.nth32->dwBlockLength = cpu_to_le32(skb_out->len);
1445 	}
1446 
1447 	/* return skb */
1448 	ctx->tx_curr_skb = NULL;
1449 
1450 	/* keep private stats: framing overhead and number of NTBs */
1451 	ctx->tx_overhead += skb_out->len - ctx->tx_curr_frame_payload;
1452 	ctx->tx_ntbs++;
1453 
1454 	/* usbnet will count all the framing overhead by default.
1455 	 * Adjust the stats so that the tx_bytes counter show real
1456 	 * payload data instead.
1457 	 */
1458 	usbnet_set_skb_tx_stats(skb_out, n,
1459 				(long)ctx->tx_curr_frame_payload - skb_out->len);
1460 
1461 	return skb_out;
1462 
1463 exit_no_skb:
1464 	/* Start timer, if there is a remaining non-empty skb */
1465 	if (ctx->tx_curr_skb != NULL && n > 0)
1466 		cdc_ncm_tx_timeout_start(ctx);
1467 	return NULL;
1468 }
1469 EXPORT_SYMBOL_GPL(cdc_ncm_fill_tx_frame);
1470 
1471 static void cdc_ncm_tx_timeout_start(struct cdc_ncm_ctx *ctx)
1472 {
1473 	/* start timer, if not already started */
1474 	if (!(hrtimer_active(&ctx->tx_timer) || atomic_read(&ctx->stop)))
1475 		hrtimer_start(&ctx->tx_timer,
1476 				ctx->timer_interval,
1477 				HRTIMER_MODE_REL);
1478 }
1479 
1480 static enum hrtimer_restart cdc_ncm_tx_timer_cb(struct hrtimer *timer)
1481 {
1482 	struct cdc_ncm_ctx *ctx =
1483 			container_of(timer, struct cdc_ncm_ctx, tx_timer);
1484 
1485 	if (!atomic_read(&ctx->stop))
1486 		tasklet_schedule(&ctx->bh);
1487 	return HRTIMER_NORESTART;
1488 }
1489 
1490 static void cdc_ncm_txpath_bh(struct tasklet_struct *t)
1491 {
1492 	struct cdc_ncm_ctx *ctx = from_tasklet(ctx, t, bh);
1493 	struct usbnet *dev = ctx->dev;
1494 
1495 	spin_lock(&ctx->mtx);
1496 	if (ctx->tx_timer_pending != 0) {
1497 		ctx->tx_timer_pending--;
1498 		cdc_ncm_tx_timeout_start(ctx);
1499 		spin_unlock(&ctx->mtx);
1500 	} else if (dev->net != NULL) {
1501 		ctx->tx_reason_timeout++;	/* count reason for transmitting */
1502 		spin_unlock(&ctx->mtx);
1503 		netif_tx_lock_bh(dev->net);
1504 		usbnet_start_xmit(NULL, dev->net);
1505 		netif_tx_unlock_bh(dev->net);
1506 	} else {
1507 		spin_unlock(&ctx->mtx);
1508 	}
1509 }
1510 
1511 struct sk_buff *
1512 cdc_ncm_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
1513 {
1514 	struct sk_buff *skb_out;
1515 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
1516 
1517 	/*
1518 	 * The Ethernet API we are using does not support transmitting
1519 	 * multiple Ethernet frames in a single call. This driver will
1520 	 * accumulate multiple Ethernet frames and send out a larger
1521 	 * USB frame when the USB buffer is full or when a single jiffies
1522 	 * timeout happens.
1523 	 */
1524 	if (ctx == NULL)
1525 		goto error;
1526 
1527 	spin_lock_bh(&ctx->mtx);
1528 
1529 	if (ctx->is_ndp16)
1530 		skb_out = cdc_ncm_fill_tx_frame(dev, skb, cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN));
1531 	else
1532 		skb_out = cdc_ncm_fill_tx_frame(dev, skb, cpu_to_le32(USB_CDC_NCM_NDP32_NOCRC_SIGN));
1533 
1534 	spin_unlock_bh(&ctx->mtx);
1535 	return skb_out;
1536 
1537 error:
1538 	if (skb != NULL)
1539 		dev_kfree_skb_any(skb);
1540 
1541 	return NULL;
1542 }
1543 EXPORT_SYMBOL_GPL(cdc_ncm_tx_fixup);
1544 
1545 /* verify NTB header and return offset of first NDP, or negative error */
1546 int cdc_ncm_rx_verify_nth16(struct cdc_ncm_ctx *ctx, struct sk_buff *skb_in)
1547 {
1548 	struct usbnet *dev = netdev_priv(skb_in->dev);
1549 	struct usb_cdc_ncm_nth16 *nth16;
1550 	int len;
1551 	int ret = -EINVAL;
1552 
1553 	if (ctx == NULL)
1554 		goto error;
1555 
1556 	if (skb_in->len < (sizeof(struct usb_cdc_ncm_nth16) +
1557 					sizeof(struct usb_cdc_ncm_ndp16))) {
1558 		netif_dbg(dev, rx_err, dev->net, "frame too short\n");
1559 		goto error;
1560 	}
1561 
1562 	nth16 = (struct usb_cdc_ncm_nth16 *)skb_in->data;
1563 
1564 	if (nth16->dwSignature != cpu_to_le32(USB_CDC_NCM_NTH16_SIGN)) {
1565 		netif_dbg(dev, rx_err, dev->net,
1566 			  "invalid NTH16 signature <%#010x>\n",
1567 			  le32_to_cpu(nth16->dwSignature));
1568 		goto error;
1569 	}
1570 
1571 	len = le16_to_cpu(nth16->wBlockLength);
1572 	if (len > ctx->rx_max) {
1573 		netif_dbg(dev, rx_err, dev->net,
1574 			  "unsupported NTB block length %u/%u\n", len,
1575 			  ctx->rx_max);
1576 		goto error;
1577 	}
1578 
1579 	if ((ctx->rx_seq + 1) != le16_to_cpu(nth16->wSequence) &&
1580 	    (ctx->rx_seq || le16_to_cpu(nth16->wSequence)) &&
1581 	    !((ctx->rx_seq == 0xffff) && !le16_to_cpu(nth16->wSequence))) {
1582 		netif_dbg(dev, rx_err, dev->net,
1583 			  "sequence number glitch prev=%d curr=%d\n",
1584 			  ctx->rx_seq, le16_to_cpu(nth16->wSequence));
1585 	}
1586 	ctx->rx_seq = le16_to_cpu(nth16->wSequence);
1587 
1588 	ret = le16_to_cpu(nth16->wNdpIndex);
1589 error:
1590 	return ret;
1591 }
1592 EXPORT_SYMBOL_GPL(cdc_ncm_rx_verify_nth16);
1593 
1594 int cdc_ncm_rx_verify_nth32(struct cdc_ncm_ctx *ctx, struct sk_buff *skb_in)
1595 {
1596 	struct usbnet *dev = netdev_priv(skb_in->dev);
1597 	struct usb_cdc_ncm_nth32 *nth32;
1598 	int len;
1599 	int ret = -EINVAL;
1600 
1601 	if (ctx == NULL)
1602 		goto error;
1603 
1604 	if (skb_in->len < (sizeof(struct usb_cdc_ncm_nth32) +
1605 					sizeof(struct usb_cdc_ncm_ndp32))) {
1606 		netif_dbg(dev, rx_err, dev->net, "frame too short\n");
1607 		goto error;
1608 	}
1609 
1610 	nth32 = (struct usb_cdc_ncm_nth32 *)skb_in->data;
1611 
1612 	if (nth32->dwSignature != cpu_to_le32(USB_CDC_NCM_NTH32_SIGN)) {
1613 		netif_dbg(dev, rx_err, dev->net,
1614 			  "invalid NTH32 signature <%#010x>\n",
1615 			  le32_to_cpu(nth32->dwSignature));
1616 		goto error;
1617 	}
1618 
1619 	len = le32_to_cpu(nth32->dwBlockLength);
1620 	if (len > ctx->rx_max) {
1621 		netif_dbg(dev, rx_err, dev->net,
1622 			  "unsupported NTB block length %u/%u\n", len,
1623 			  ctx->rx_max);
1624 		goto error;
1625 	}
1626 
1627 	if ((ctx->rx_seq + 1) != le16_to_cpu(nth32->wSequence) &&
1628 	    (ctx->rx_seq || le16_to_cpu(nth32->wSequence)) &&
1629 	    !((ctx->rx_seq == 0xffff) && !le16_to_cpu(nth32->wSequence))) {
1630 		netif_dbg(dev, rx_err, dev->net,
1631 			  "sequence number glitch prev=%d curr=%d\n",
1632 			  ctx->rx_seq, le16_to_cpu(nth32->wSequence));
1633 	}
1634 	ctx->rx_seq = le16_to_cpu(nth32->wSequence);
1635 
1636 	ret = le32_to_cpu(nth32->dwNdpIndex);
1637 error:
1638 	return ret;
1639 }
1640 EXPORT_SYMBOL_GPL(cdc_ncm_rx_verify_nth32);
1641 
1642 /* verify NDP header and return number of datagrams, or negative error */
1643 int cdc_ncm_rx_verify_ndp16(struct sk_buff *skb_in, int ndpoffset)
1644 {
1645 	struct usbnet *dev = netdev_priv(skb_in->dev);
1646 	struct usb_cdc_ncm_ndp16 *ndp16;
1647 	int ret = -EINVAL;
1648 
1649 	if ((ndpoffset + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len) {
1650 		netif_dbg(dev, rx_err, dev->net, "invalid NDP offset  <%u>\n",
1651 			  ndpoffset);
1652 		goto error;
1653 	}
1654 	ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
1655 
1656 	if (le16_to_cpu(ndp16->wLength) < USB_CDC_NCM_NDP16_LENGTH_MIN) {
1657 		netif_dbg(dev, rx_err, dev->net, "invalid DPT16 length <%u>\n",
1658 			  le16_to_cpu(ndp16->wLength));
1659 		goto error;
1660 	}
1661 
1662 	ret = ((le16_to_cpu(ndp16->wLength) -
1663 					sizeof(struct usb_cdc_ncm_ndp16)) /
1664 					sizeof(struct usb_cdc_ncm_dpe16));
1665 	ret--; /* we process NDP entries except for the last one */
1666 
1667 	if ((sizeof(struct usb_cdc_ncm_ndp16) +
1668 	     ret * (sizeof(struct usb_cdc_ncm_dpe16))) > skb_in->len) {
1669 		netif_dbg(dev, rx_err, dev->net, "Invalid nframes = %d\n", ret);
1670 		ret = -EINVAL;
1671 	}
1672 
1673 error:
1674 	return ret;
1675 }
1676 EXPORT_SYMBOL_GPL(cdc_ncm_rx_verify_ndp16);
1677 
1678 /* verify NDP header and return number of datagrams, or negative error */
1679 int cdc_ncm_rx_verify_ndp32(struct sk_buff *skb_in, int ndpoffset)
1680 {
1681 	struct usbnet *dev = netdev_priv(skb_in->dev);
1682 	struct usb_cdc_ncm_ndp32 *ndp32;
1683 	int ret = -EINVAL;
1684 
1685 	if ((ndpoffset + sizeof(struct usb_cdc_ncm_ndp32)) > skb_in->len) {
1686 		netif_dbg(dev, rx_err, dev->net, "invalid NDP offset  <%u>\n",
1687 			  ndpoffset);
1688 		goto error;
1689 	}
1690 	ndp32 = (struct usb_cdc_ncm_ndp32 *)(skb_in->data + ndpoffset);
1691 
1692 	if (le16_to_cpu(ndp32->wLength) < USB_CDC_NCM_NDP32_LENGTH_MIN) {
1693 		netif_dbg(dev, rx_err, dev->net, "invalid DPT32 length <%u>\n",
1694 			  le16_to_cpu(ndp32->wLength));
1695 		goto error;
1696 	}
1697 
1698 	ret = ((le16_to_cpu(ndp32->wLength) -
1699 					sizeof(struct usb_cdc_ncm_ndp32)) /
1700 					sizeof(struct usb_cdc_ncm_dpe32));
1701 	ret--; /* we process NDP entries except for the last one */
1702 
1703 	if ((sizeof(struct usb_cdc_ncm_ndp32) +
1704 	     ret * (sizeof(struct usb_cdc_ncm_dpe32))) > skb_in->len) {
1705 		netif_dbg(dev, rx_err, dev->net, "Invalid nframes = %d\n", ret);
1706 		ret = -EINVAL;
1707 	}
1708 
1709 error:
1710 	return ret;
1711 }
1712 EXPORT_SYMBOL_GPL(cdc_ncm_rx_verify_ndp32);
1713 
1714 int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
1715 {
1716 	struct sk_buff *skb;
1717 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
1718 	unsigned int len;
1719 	int nframes;
1720 	int x;
1721 	unsigned int offset;
1722 	union {
1723 		struct usb_cdc_ncm_ndp16 *ndp16;
1724 		struct usb_cdc_ncm_ndp32 *ndp32;
1725 	} ndp;
1726 	union {
1727 		struct usb_cdc_ncm_dpe16 *dpe16;
1728 		struct usb_cdc_ncm_dpe32 *dpe32;
1729 	} dpe;
1730 
1731 	int ndpoffset;
1732 	int loopcount = 50; /* arbitrary max preventing infinite loop */
1733 	u32 payload = 0;
1734 
1735 	if (ctx->is_ndp16)
1736 		ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
1737 	else
1738 		ndpoffset = cdc_ncm_rx_verify_nth32(ctx, skb_in);
1739 
1740 	if (ndpoffset < 0)
1741 		goto error;
1742 
1743 next_ndp:
1744 	if (ctx->is_ndp16) {
1745 		nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
1746 		if (nframes < 0)
1747 			goto error;
1748 
1749 		ndp.ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
1750 
1751 		if (ndp.ndp16->dwSignature != cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN)) {
1752 			netif_dbg(dev, rx_err, dev->net,
1753 				  "invalid DPT16 signature <%#010x>\n",
1754 				  le32_to_cpu(ndp.ndp16->dwSignature));
1755 			goto err_ndp;
1756 		}
1757 		dpe.dpe16 = ndp.ndp16->dpe16;
1758 	} else {
1759 		nframes = cdc_ncm_rx_verify_ndp32(skb_in, ndpoffset);
1760 		if (nframes < 0)
1761 			goto error;
1762 
1763 		ndp.ndp32 = (struct usb_cdc_ncm_ndp32 *)(skb_in->data + ndpoffset);
1764 
1765 		if (ndp.ndp32->dwSignature != cpu_to_le32(USB_CDC_NCM_NDP32_NOCRC_SIGN)) {
1766 			netif_dbg(dev, rx_err, dev->net,
1767 				  "invalid DPT32 signature <%#010x>\n",
1768 				  le32_to_cpu(ndp.ndp32->dwSignature));
1769 			goto err_ndp;
1770 		}
1771 		dpe.dpe32 = ndp.ndp32->dpe32;
1772 	}
1773 
1774 	for (x = 0; x < nframes; x++) {
1775 		if (ctx->is_ndp16) {
1776 			offset = le16_to_cpu(dpe.dpe16->wDatagramIndex);
1777 			len = le16_to_cpu(dpe.dpe16->wDatagramLength);
1778 		} else {
1779 			offset = le32_to_cpu(dpe.dpe32->dwDatagramIndex);
1780 			len = le32_to_cpu(dpe.dpe32->dwDatagramLength);
1781 		}
1782 
1783 		/*
1784 		 * CDC NCM ch. 3.7
1785 		 * All entries after first NULL entry are to be ignored
1786 		 */
1787 		if ((offset == 0) || (len == 0)) {
1788 			if (!x)
1789 				goto err_ndp; /* empty NTB */
1790 			break;
1791 		}
1792 
1793 		/* sanity checking - watch out for integer wrap*/
1794 		if ((offset > skb_in->len) || (len > skb_in->len - offset) ||
1795 				(len > ctx->rx_max) || (len < ETH_HLEN)) {
1796 			netif_dbg(dev, rx_err, dev->net,
1797 				  "invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
1798 				  x, offset, len, skb_in);
1799 			if (!x)
1800 				goto err_ndp;
1801 			break;
1802 
1803 		} else {
1804 			/* create a fresh copy to reduce truesize */
1805 			skb = netdev_alloc_skb_ip_align(dev->net,  len);
1806 			if (!skb)
1807 				goto error;
1808 			skb_put_data(skb, skb_in->data + offset, len);
1809 			usbnet_skb_return(dev, skb);
1810 			payload += len;	/* count payload bytes in this NTB */
1811 		}
1812 
1813 		if (ctx->is_ndp16)
1814 			dpe.dpe16++;
1815 		else
1816 			dpe.dpe32++;
1817 	}
1818 err_ndp:
1819 	/* are there more NDPs to process? */
1820 	if (ctx->is_ndp16)
1821 		ndpoffset = le16_to_cpu(ndp.ndp16->wNextNdpIndex);
1822 	else
1823 		ndpoffset = le32_to_cpu(ndp.ndp32->dwNextNdpIndex);
1824 
1825 	if (ndpoffset && loopcount--)
1826 		goto next_ndp;
1827 
1828 	/* update stats */
1829 	ctx->rx_overhead += skb_in->len - payload;
1830 	ctx->rx_ntbs++;
1831 
1832 	return 1;
1833 error:
1834 	return 0;
1835 }
1836 EXPORT_SYMBOL_GPL(cdc_ncm_rx_fixup);
1837 
1838 static void
1839 cdc_ncm_speed_change(struct usbnet *dev,
1840 		     struct usb_cdc_speed_change *data)
1841 {
1842 	/* RTL8156 shipped before 2021 sends notification about every 32ms. */
1843 	dev->rx_speed = le32_to_cpu(data->DLBitRRate);
1844 	dev->tx_speed = le32_to_cpu(data->ULBitRate);
1845 }
1846 
1847 static void cdc_ncm_status(struct usbnet *dev, struct urb *urb)
1848 {
1849 	struct usb_cdc_notification *event;
1850 
1851 	if (urb->actual_length < sizeof(*event))
1852 		return;
1853 
1854 	/* test for split data in 8-byte chunks */
1855 	if (test_and_clear_bit(EVENT_STS_SPLIT, &dev->flags)) {
1856 		cdc_ncm_speed_change(dev,
1857 		      (struct usb_cdc_speed_change *)urb->transfer_buffer);
1858 		return;
1859 	}
1860 
1861 	event = urb->transfer_buffer;
1862 
1863 	switch (event->bNotificationType) {
1864 	case USB_CDC_NOTIFY_NETWORK_CONNECTION:
1865 		/*
1866 		 * According to the CDC NCM specification ch.7.1
1867 		 * USB_CDC_NOTIFY_NETWORK_CONNECTION notification shall be
1868 		 * sent by device after USB_CDC_NOTIFY_SPEED_CHANGE.
1869 		 */
1870 		/* RTL8156 shipped before 2021 sends notification about
1871 		 * every 32ms. Don't forward notification if state is same.
1872 		 */
1873 		if (netif_carrier_ok(dev->net) != !!event->wValue)
1874 			usbnet_link_change(dev, !!event->wValue, 0);
1875 		break;
1876 
1877 	case USB_CDC_NOTIFY_SPEED_CHANGE:
1878 		if (urb->actual_length < (sizeof(*event) +
1879 					sizeof(struct usb_cdc_speed_change)))
1880 			set_bit(EVENT_STS_SPLIT, &dev->flags);
1881 		else
1882 			cdc_ncm_speed_change(dev,
1883 					     (struct usb_cdc_speed_change *)&event[1]);
1884 		break;
1885 
1886 	default:
1887 		dev_dbg(&dev->udev->dev,
1888 			"NCM: unexpected notification 0x%02x!\n",
1889 			event->bNotificationType);
1890 		break;
1891 	}
1892 }
1893 
1894 static const struct driver_info cdc_ncm_info = {
1895 	.description = "CDC NCM (NO ZLP)",
1896 	.flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
1897 			| FLAG_LINK_INTR | FLAG_ETHER,
1898 	.bind = cdc_ncm_bind,
1899 	.unbind = cdc_ncm_unbind,
1900 	.manage_power = usbnet_manage_power,
1901 	.status = cdc_ncm_status,
1902 	.rx_fixup = cdc_ncm_rx_fixup,
1903 	.tx_fixup = cdc_ncm_tx_fixup,
1904 	.set_rx_mode = usbnet_cdc_update_filter,
1905 };
1906 
1907 /* Same as cdc_ncm_info, but with FLAG_SEND_ZLP  */
1908 static const struct driver_info cdc_ncm_zlp_info = {
1909 	.description = "CDC NCM (SEND ZLP)",
1910 	.flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
1911 			| FLAG_LINK_INTR | FLAG_ETHER | FLAG_SEND_ZLP,
1912 	.bind = cdc_ncm_bind,
1913 	.unbind = cdc_ncm_unbind,
1914 	.manage_power = usbnet_manage_power,
1915 	.status = cdc_ncm_status,
1916 	.rx_fixup = cdc_ncm_rx_fixup,
1917 	.tx_fixup = cdc_ncm_tx_fixup,
1918 };
1919 
1920 /* Same as cdc_ncm_info, but with FLAG_WWAN */
1921 static const struct driver_info wwan_info = {
1922 	.description = "Mobile Broadband Network Device",
1923 	.flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
1924 			| FLAG_LINK_INTR | FLAG_WWAN,
1925 	.bind = cdc_ncm_bind,
1926 	.unbind = cdc_ncm_unbind,
1927 	.manage_power = usbnet_manage_power,
1928 	.status = cdc_ncm_status,
1929 	.rx_fixup = cdc_ncm_rx_fixup,
1930 	.tx_fixup = cdc_ncm_tx_fixup,
1931 	.set_rx_mode = usbnet_cdc_update_filter,
1932 };
1933 
1934 /* Same as wwan_info, but with FLAG_NOARP  */
1935 static const struct driver_info wwan_noarp_info = {
1936 	.description = "Mobile Broadband Network Device (NO ARP)",
1937 	.flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
1938 			| FLAG_LINK_INTR | FLAG_WWAN | FLAG_NOARP,
1939 	.bind = cdc_ncm_bind,
1940 	.unbind = cdc_ncm_unbind,
1941 	.manage_power = usbnet_manage_power,
1942 	.status = cdc_ncm_status,
1943 	.rx_fixup = cdc_ncm_rx_fixup,
1944 	.tx_fixup = cdc_ncm_tx_fixup,
1945 	.set_rx_mode = usbnet_cdc_update_filter,
1946 };
1947 
1948 static const struct usb_device_id cdc_devs[] = {
1949 	/* Ericsson MBM devices like F5521gw */
1950 	{ .match_flags = USB_DEVICE_ID_MATCH_INT_INFO
1951 		| USB_DEVICE_ID_MATCH_VENDOR,
1952 	  .idVendor = 0x0bdb,
1953 	  .bInterfaceClass = USB_CLASS_COMM,
1954 	  .bInterfaceSubClass = USB_CDC_SUBCLASS_NCM,
1955 	  .bInterfaceProtocol = USB_CDC_PROTO_NONE,
1956 	  .driver_info = (unsigned long) &wwan_info,
1957 	},
1958 
1959 	/* Telit LE910 V2 */
1960 	{ USB_DEVICE_AND_INTERFACE_INFO(0x1bc7, 0x0036,
1961 		USB_CLASS_COMM,
1962 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
1963 	  .driver_info = (unsigned long)&wwan_noarp_info,
1964 	},
1965 
1966 	/* DW5812 LTE Verizon Mobile Broadband Card
1967 	 * Unlike DW5550 this device requires FLAG_NOARP
1968 	 */
1969 	{ USB_DEVICE_AND_INTERFACE_INFO(0x413c, 0x81bb,
1970 		USB_CLASS_COMM,
1971 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
1972 	  .driver_info = (unsigned long)&wwan_noarp_info,
1973 	},
1974 
1975 	/* DW5813 LTE AT&T Mobile Broadband Card
1976 	 * Unlike DW5550 this device requires FLAG_NOARP
1977 	 */
1978 	{ USB_DEVICE_AND_INTERFACE_INFO(0x413c, 0x81bc,
1979 		USB_CLASS_COMM,
1980 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
1981 	  .driver_info = (unsigned long)&wwan_noarp_info,
1982 	},
1983 
1984 	/* Dell branded MBM devices like DW5550 */
1985 	{ .match_flags = USB_DEVICE_ID_MATCH_INT_INFO
1986 		| USB_DEVICE_ID_MATCH_VENDOR,
1987 	  .idVendor = 0x413c,
1988 	  .bInterfaceClass = USB_CLASS_COMM,
1989 	  .bInterfaceSubClass = USB_CDC_SUBCLASS_NCM,
1990 	  .bInterfaceProtocol = USB_CDC_PROTO_NONE,
1991 	  .driver_info = (unsigned long) &wwan_info,
1992 	},
1993 
1994 	/* Toshiba branded MBM devices */
1995 	{ .match_flags = USB_DEVICE_ID_MATCH_INT_INFO
1996 		| USB_DEVICE_ID_MATCH_VENDOR,
1997 	  .idVendor = 0x0930,
1998 	  .bInterfaceClass = USB_CLASS_COMM,
1999 	  .bInterfaceSubClass = USB_CDC_SUBCLASS_NCM,
2000 	  .bInterfaceProtocol = USB_CDC_PROTO_NONE,
2001 	  .driver_info = (unsigned long) &wwan_info,
2002 	},
2003 
2004 	/* tag Huawei devices as wwan */
2005 	{ USB_VENDOR_AND_INTERFACE_INFO(0x12d1,
2006 					USB_CLASS_COMM,
2007 					USB_CDC_SUBCLASS_NCM,
2008 					USB_CDC_PROTO_NONE),
2009 	  .driver_info = (unsigned long)&wwan_info,
2010 	},
2011 
2012 	/* Infineon(now Intel) HSPA Modem platform */
2013 	{ USB_DEVICE_AND_INTERFACE_INFO(0x1519, 0x0443,
2014 		USB_CLASS_COMM,
2015 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
2016 	  .driver_info = (unsigned long)&wwan_noarp_info,
2017 	},
2018 
2019 	/* u-blox TOBY-L4 */
2020 	{ USB_DEVICE_AND_INTERFACE_INFO(0x1546, 0x1010,
2021 		USB_CLASS_COMM,
2022 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
2023 	  .driver_info = (unsigned long)&wwan_info,
2024 	},
2025 
2026 	/* DisplayLink docking stations */
2027 	{ .match_flags = USB_DEVICE_ID_MATCH_INT_INFO
2028 		| USB_DEVICE_ID_MATCH_VENDOR,
2029 	  .idVendor = 0x17e9,
2030 	  .bInterfaceClass = USB_CLASS_COMM,
2031 	  .bInterfaceSubClass = USB_CDC_SUBCLASS_NCM,
2032 	  .bInterfaceProtocol = USB_CDC_PROTO_NONE,
2033 	  .driver_info = (unsigned long)&cdc_ncm_zlp_info,
2034 	},
2035 
2036 	/* Generic CDC-NCM devices */
2037 	{ USB_INTERFACE_INFO(USB_CLASS_COMM,
2038 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
2039 		.driver_info = (unsigned long)&cdc_ncm_info,
2040 	},
2041 	{
2042 	},
2043 };
2044 MODULE_DEVICE_TABLE(usb, cdc_devs);
2045 
2046 static struct usb_driver cdc_ncm_driver = {
2047 	.name = "cdc_ncm",
2048 	.id_table = cdc_devs,
2049 	.probe = usbnet_probe,
2050 	.disconnect = usbnet_disconnect,
2051 	.suspend = usbnet_suspend,
2052 	.resume = usbnet_resume,
2053 	.reset_resume =	usbnet_resume,
2054 	.supports_autosuspend = 1,
2055 	.disable_hub_initiated_lpm = 1,
2056 };
2057 
2058 module_usb_driver(cdc_ncm_driver);
2059 
2060 MODULE_AUTHOR("Hans Petter Selasky");
2061 MODULE_DESCRIPTION("USB CDC NCM host driver");
2062 MODULE_LICENSE("Dual BSD/GPL");
2063