xref: /openbmc/linux/drivers/net/usb/cdc_ncm.c (revision 50df3be7)
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(unsigned long param);
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,
146 	.set_link_ksettings      = usbnet_set_link_ksettings,
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 	min = ctx->max_datagram_size + ctx->max_ndp_size + sizeof(struct usb_cdc_ncm_nth16);
179 	max = min_t(u32, CDC_NCM_NTB_MAX_SIZE_TX, le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize));
180 
181 	/* some devices set dwNtbOutMaxSize too low for the above default */
182 	min = min(min, max);
183 
184 	val = clamp_t(u32, new_tx, min, max);
185 	if (val != new_tx)
186 		dev_dbg(&dev->intf->dev, "tx_max must be in the [%u, %u] range\n", min, max);
187 
188 	return val;
189 }
190 
191 static ssize_t cdc_ncm_show_min_tx_pkt(struct device *d, struct device_attribute *attr, char *buf)
192 {
193 	struct usbnet *dev = netdev_priv(to_net_dev(d));
194 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
195 
196 	return sprintf(buf, "%u\n", ctx->min_tx_pkt);
197 }
198 
199 static ssize_t cdc_ncm_show_rx_max(struct device *d, struct device_attribute *attr, char *buf)
200 {
201 	struct usbnet *dev = netdev_priv(to_net_dev(d));
202 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
203 
204 	return sprintf(buf, "%u\n", ctx->rx_max);
205 }
206 
207 static ssize_t cdc_ncm_show_tx_max(struct device *d, 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->tx_max);
213 }
214 
215 static ssize_t cdc_ncm_show_tx_timer_usecs(struct device *d, struct device_attribute *attr, char *buf)
216 {
217 	struct usbnet *dev = netdev_priv(to_net_dev(d));
218 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
219 
220 	return sprintf(buf, "%u\n", ctx->timer_interval / (u32)NSEC_PER_USEC);
221 }
222 
223 static ssize_t cdc_ncm_store_min_tx_pkt(struct device *d,  struct device_attribute *attr, const char *buf, size_t len)
224 {
225 	struct usbnet *dev = netdev_priv(to_net_dev(d));
226 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
227 	unsigned long val;
228 
229 	/* no need to restrict values - anything from 0 to infinity is OK */
230 	if (kstrtoul(buf, 0, &val))
231 		return -EINVAL;
232 
233 	ctx->min_tx_pkt = val;
234 	return len;
235 }
236 
237 static ssize_t cdc_ncm_store_rx_max(struct device *d,  struct device_attribute *attr, const char *buf, size_t len)
238 {
239 	struct usbnet *dev = netdev_priv(to_net_dev(d));
240 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
241 	unsigned long val;
242 
243 	if (kstrtoul(buf, 0, &val) || cdc_ncm_check_rx_max(dev, val) != val)
244 		return -EINVAL;
245 
246 	cdc_ncm_update_rxtx_max(dev, val, ctx->tx_max);
247 	return len;
248 }
249 
250 static ssize_t cdc_ncm_store_tx_max(struct device *d,  struct device_attribute *attr, const char *buf, size_t len)
251 {
252 	struct usbnet *dev = netdev_priv(to_net_dev(d));
253 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
254 	unsigned long val;
255 
256 	if (kstrtoul(buf, 0, &val) || cdc_ncm_check_tx_max(dev, val) != val)
257 		return -EINVAL;
258 
259 	cdc_ncm_update_rxtx_max(dev, ctx->rx_max, val);
260 	return len;
261 }
262 
263 static ssize_t cdc_ncm_store_tx_timer_usecs(struct device *d,  struct device_attribute *attr, const char *buf, size_t len)
264 {
265 	struct usbnet *dev = netdev_priv(to_net_dev(d));
266 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
267 	ssize_t ret;
268 	unsigned long val;
269 
270 	ret = kstrtoul(buf, 0, &val);
271 	if (ret)
272 		return ret;
273 	if (val && (val < CDC_NCM_TIMER_INTERVAL_MIN || val > CDC_NCM_TIMER_INTERVAL_MAX))
274 		return -EINVAL;
275 
276 	spin_lock_bh(&ctx->mtx);
277 	ctx->timer_interval = val * NSEC_PER_USEC;
278 	if (!ctx->timer_interval)
279 		ctx->tx_timer_pending = 0;
280 	spin_unlock_bh(&ctx->mtx);
281 	return len;
282 }
283 
284 static DEVICE_ATTR(min_tx_pkt, 0644, cdc_ncm_show_min_tx_pkt, cdc_ncm_store_min_tx_pkt);
285 static DEVICE_ATTR(rx_max, 0644, cdc_ncm_show_rx_max, cdc_ncm_store_rx_max);
286 static DEVICE_ATTR(tx_max, 0644, cdc_ncm_show_tx_max, cdc_ncm_store_tx_max);
287 static DEVICE_ATTR(tx_timer_usecs, 0644, cdc_ncm_show_tx_timer_usecs, cdc_ncm_store_tx_timer_usecs);
288 
289 static ssize_t ndp_to_end_show(struct device *d, struct device_attribute *attr, char *buf)
290 {
291 	struct usbnet *dev = netdev_priv(to_net_dev(d));
292 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
293 
294 	return sprintf(buf, "%c\n", ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END ? 'Y' : 'N');
295 }
296 
297 static ssize_t ndp_to_end_store(struct device *d,  struct device_attribute *attr, const char *buf, size_t len)
298 {
299 	struct usbnet *dev = netdev_priv(to_net_dev(d));
300 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
301 	bool enable;
302 
303 	if (strtobool(buf, &enable))
304 		return -EINVAL;
305 
306 	/* no change? */
307 	if (enable == (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))
308 		return len;
309 
310 	if (enable && !ctx->delayed_ndp16) {
311 		ctx->delayed_ndp16 = kzalloc(ctx->max_ndp_size, GFP_KERNEL);
312 		if (!ctx->delayed_ndp16)
313 			return -ENOMEM;
314 	}
315 
316 	/* flush pending data before changing flag */
317 	netif_tx_lock_bh(dev->net);
318 	usbnet_start_xmit(NULL, dev->net);
319 	spin_lock_bh(&ctx->mtx);
320 	if (enable)
321 		ctx->drvflags |= CDC_NCM_FLAG_NDP_TO_END;
322 	else
323 		ctx->drvflags &= ~CDC_NCM_FLAG_NDP_TO_END;
324 	spin_unlock_bh(&ctx->mtx);
325 	netif_tx_unlock_bh(dev->net);
326 
327 	return len;
328 }
329 static DEVICE_ATTR_RW(ndp_to_end);
330 
331 #define NCM_PARM_ATTR(name, format, tocpu)				\
332 static ssize_t cdc_ncm_show_##name(struct device *d, struct device_attribute *attr, char *buf) \
333 { \
334 	struct usbnet *dev = netdev_priv(to_net_dev(d)); \
335 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0]; \
336 	return sprintf(buf, format "\n", tocpu(ctx->ncm_parm.name));	\
337 } \
338 static DEVICE_ATTR(name, 0444, cdc_ncm_show_##name, NULL)
339 
340 NCM_PARM_ATTR(bmNtbFormatsSupported, "0x%04x", le16_to_cpu);
341 NCM_PARM_ATTR(dwNtbInMaxSize, "%u", le32_to_cpu);
342 NCM_PARM_ATTR(wNdpInDivisor, "%u", le16_to_cpu);
343 NCM_PARM_ATTR(wNdpInPayloadRemainder, "%u", le16_to_cpu);
344 NCM_PARM_ATTR(wNdpInAlignment, "%u", le16_to_cpu);
345 NCM_PARM_ATTR(dwNtbOutMaxSize, "%u", le32_to_cpu);
346 NCM_PARM_ATTR(wNdpOutDivisor, "%u", le16_to_cpu);
347 NCM_PARM_ATTR(wNdpOutPayloadRemainder, "%u", le16_to_cpu);
348 NCM_PARM_ATTR(wNdpOutAlignment, "%u", le16_to_cpu);
349 NCM_PARM_ATTR(wNtbOutMaxDatagrams, "%u", le16_to_cpu);
350 
351 static struct attribute *cdc_ncm_sysfs_attrs[] = {
352 	&dev_attr_min_tx_pkt.attr,
353 	&dev_attr_ndp_to_end.attr,
354 	&dev_attr_rx_max.attr,
355 	&dev_attr_tx_max.attr,
356 	&dev_attr_tx_timer_usecs.attr,
357 	&dev_attr_bmNtbFormatsSupported.attr,
358 	&dev_attr_dwNtbInMaxSize.attr,
359 	&dev_attr_wNdpInDivisor.attr,
360 	&dev_attr_wNdpInPayloadRemainder.attr,
361 	&dev_attr_wNdpInAlignment.attr,
362 	&dev_attr_dwNtbOutMaxSize.attr,
363 	&dev_attr_wNdpOutDivisor.attr,
364 	&dev_attr_wNdpOutPayloadRemainder.attr,
365 	&dev_attr_wNdpOutAlignment.attr,
366 	&dev_attr_wNtbOutMaxDatagrams.attr,
367 	NULL,
368 };
369 
370 static const struct attribute_group cdc_ncm_sysfs_attr_group = {
371 	.name = "cdc_ncm",
372 	.attrs = cdc_ncm_sysfs_attrs,
373 };
374 
375 /* handle rx_max and tx_max changes */
376 static void cdc_ncm_update_rxtx_max(struct usbnet *dev, u32 new_rx, u32 new_tx)
377 {
378 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
379 	u8 iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;
380 	u32 val;
381 
382 	val = cdc_ncm_check_rx_max(dev, new_rx);
383 
384 	/* inform device about NTB input size changes */
385 	if (val != ctx->rx_max) {
386 		__le32 dwNtbInMaxSize = cpu_to_le32(val);
387 
388 		dev_info(&dev->intf->dev, "setting rx_max = %u\n", val);
389 
390 		/* tell device to use new size */
391 		if (usbnet_write_cmd(dev, USB_CDC_SET_NTB_INPUT_SIZE,
392 				     USB_TYPE_CLASS | USB_DIR_OUT
393 				     | USB_RECIP_INTERFACE,
394 				     0, iface_no, &dwNtbInMaxSize, 4) < 0)
395 			dev_dbg(&dev->intf->dev, "Setting NTB Input Size failed\n");
396 		else
397 			ctx->rx_max = val;
398 	}
399 
400 	/* usbnet use these values for sizing rx queues */
401 	if (dev->rx_urb_size != ctx->rx_max) {
402 		dev->rx_urb_size = ctx->rx_max;
403 		if (netif_running(dev->net))
404 			usbnet_unlink_rx_urbs(dev);
405 	}
406 
407 	val = cdc_ncm_check_tx_max(dev, new_tx);
408 	if (val != ctx->tx_max)
409 		dev_info(&dev->intf->dev, "setting tx_max = %u\n", val);
410 
411 	/* Adding a pad byte here if necessary simplifies the handling
412 	 * in cdc_ncm_fill_tx_frame, making tx_max always represent
413 	 * the real skb max size.
414 	 *
415 	 * We cannot use dev->maxpacket here because this is called from
416 	 * .bind which is called before usbnet sets up dev->maxpacket
417 	 */
418 	if (val != le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize) &&
419 	    val % usb_maxpacket(dev->udev, dev->out, 1) == 0)
420 		val++;
421 
422 	/* we might need to flush any pending tx buffers if running */
423 	if (netif_running(dev->net) && val > ctx->tx_max) {
424 		netif_tx_lock_bh(dev->net);
425 		usbnet_start_xmit(NULL, dev->net);
426 		/* make sure tx_curr_skb is reallocated if it was empty */
427 		if (ctx->tx_curr_skb) {
428 			dev_kfree_skb_any(ctx->tx_curr_skb);
429 			ctx->tx_curr_skb = NULL;
430 		}
431 		ctx->tx_max = val;
432 		netif_tx_unlock_bh(dev->net);
433 	} else {
434 		ctx->tx_max = val;
435 	}
436 
437 	dev->hard_mtu = ctx->tx_max;
438 
439 	/* max qlen depend on hard_mtu and rx_urb_size */
440 	usbnet_update_max_qlen(dev);
441 
442 	/* never pad more than 3 full USB packets per transfer */
443 	ctx->min_tx_pkt = clamp_t(u16, ctx->tx_max - 3 * usb_maxpacket(dev->udev, dev->out, 1),
444 				  CDC_NCM_MIN_TX_PKT, ctx->tx_max);
445 }
446 
447 /* helpers for NCM and MBIM differences */
448 static u8 cdc_ncm_flags(struct usbnet *dev)
449 {
450 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
451 
452 	if (cdc_ncm_comm_intf_is_mbim(dev->intf->cur_altsetting) && ctx->mbim_desc)
453 		return ctx->mbim_desc->bmNetworkCapabilities;
454 	if (ctx->func_desc)
455 		return ctx->func_desc->bmNetworkCapabilities;
456 	return 0;
457 }
458 
459 static int cdc_ncm_eth_hlen(struct usbnet *dev)
460 {
461 	if (cdc_ncm_comm_intf_is_mbim(dev->intf->cur_altsetting))
462 		return 0;
463 	return ETH_HLEN;
464 }
465 
466 static u32 cdc_ncm_min_dgram_size(struct usbnet *dev)
467 {
468 	if (cdc_ncm_comm_intf_is_mbim(dev->intf->cur_altsetting))
469 		return CDC_MBIM_MIN_DATAGRAM_SIZE;
470 	return CDC_NCM_MIN_DATAGRAM_SIZE;
471 }
472 
473 static u32 cdc_ncm_max_dgram_size(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 le16_to_cpu(ctx->mbim_desc->wMaxSegmentSize);
479 	if (ctx->ether_desc)
480 		return le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);
481 	return CDC_NCM_MAX_DATAGRAM_SIZE;
482 }
483 
484 /* initial one-time device setup.  MUST be called with the data interface
485  * in altsetting 0
486  */
487 static int cdc_ncm_init(struct usbnet *dev)
488 {
489 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
490 	u8 iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;
491 	int err;
492 
493 	err = usbnet_read_cmd(dev, USB_CDC_GET_NTB_PARAMETERS,
494 			      USB_TYPE_CLASS | USB_DIR_IN
495 			      |USB_RECIP_INTERFACE,
496 			      0, iface_no, &ctx->ncm_parm,
497 			      sizeof(ctx->ncm_parm));
498 	if (err < 0) {
499 		dev_err(&dev->intf->dev, "failed GET_NTB_PARAMETERS\n");
500 		return err; /* GET_NTB_PARAMETERS is required */
501 	}
502 
503 	/* set CRC Mode */
504 	if (cdc_ncm_flags(dev) & USB_CDC_NCM_NCAP_CRC_MODE) {
505 		dev_dbg(&dev->intf->dev, "Setting CRC mode off\n");
506 		err = usbnet_write_cmd(dev, USB_CDC_SET_CRC_MODE,
507 				       USB_TYPE_CLASS | USB_DIR_OUT
508 				       | USB_RECIP_INTERFACE,
509 				       USB_CDC_NCM_CRC_NOT_APPENDED,
510 				       iface_no, NULL, 0);
511 		if (err < 0)
512 			dev_err(&dev->intf->dev, "SET_CRC_MODE failed\n");
513 	}
514 
515 	/* set NTB format, if both formats are supported.
516 	 *
517 	 * "The host shall only send this command while the NCM Data
518 	 *  Interface is in alternate setting 0."
519 	 */
520 	if (le16_to_cpu(ctx->ncm_parm.bmNtbFormatsSupported) &
521 						USB_CDC_NCM_NTB32_SUPPORTED) {
522 		dev_dbg(&dev->intf->dev, "Setting NTB format to 16-bit\n");
523 		err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_FORMAT,
524 				       USB_TYPE_CLASS | USB_DIR_OUT
525 				       | USB_RECIP_INTERFACE,
526 				       USB_CDC_NCM_NTB16_FORMAT,
527 				       iface_no, NULL, 0);
528 		if (err < 0)
529 			dev_err(&dev->intf->dev, "SET_NTB_FORMAT failed\n");
530 	}
531 
532 	/* set initial device values */
533 	ctx->rx_max = le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize);
534 	ctx->tx_max = le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize);
535 	ctx->tx_remainder = le16_to_cpu(ctx->ncm_parm.wNdpOutPayloadRemainder);
536 	ctx->tx_modulus = le16_to_cpu(ctx->ncm_parm.wNdpOutDivisor);
537 	ctx->tx_ndp_modulus = le16_to_cpu(ctx->ncm_parm.wNdpOutAlignment);
538 	/* devices prior to NCM Errata shall set this field to zero */
539 	ctx->tx_max_datagrams = le16_to_cpu(ctx->ncm_parm.wNtbOutMaxDatagrams);
540 
541 	dev_dbg(&dev->intf->dev,
542 		"dwNtbInMaxSize=%u dwNtbOutMaxSize=%u wNdpOutPayloadRemainder=%u wNdpOutDivisor=%u wNdpOutAlignment=%u wNtbOutMaxDatagrams=%u flags=0x%x\n",
543 		ctx->rx_max, ctx->tx_max, ctx->tx_remainder, ctx->tx_modulus,
544 		ctx->tx_ndp_modulus, ctx->tx_max_datagrams, cdc_ncm_flags(dev));
545 
546 	/* max count of tx datagrams */
547 	if ((ctx->tx_max_datagrams == 0) ||
548 			(ctx->tx_max_datagrams > CDC_NCM_DPT_DATAGRAMS_MAX))
549 		ctx->tx_max_datagrams = CDC_NCM_DPT_DATAGRAMS_MAX;
550 
551 	/* set up maximum NDP size */
552 	ctx->max_ndp_size = sizeof(struct usb_cdc_ncm_ndp16) + (ctx->tx_max_datagrams + 1) * sizeof(struct usb_cdc_ncm_dpe16);
553 
554 	/* initial coalescing timer interval */
555 	ctx->timer_interval = CDC_NCM_TIMER_INTERVAL_USEC * NSEC_PER_USEC;
556 
557 	return 0;
558 }
559 
560 /* set a new max datagram size */
561 static void cdc_ncm_set_dgram_size(struct usbnet *dev, int new_size)
562 {
563 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
564 	u8 iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;
565 	__le16 max_datagram_size;
566 	u16 mbim_mtu;
567 	int err;
568 
569 	/* set default based on descriptors */
570 	ctx->max_datagram_size = clamp_t(u32, new_size,
571 					 cdc_ncm_min_dgram_size(dev),
572 					 CDC_NCM_MAX_DATAGRAM_SIZE);
573 
574 	/* inform the device about the selected Max Datagram Size? */
575 	if (!(cdc_ncm_flags(dev) & USB_CDC_NCM_NCAP_MAX_DATAGRAM_SIZE))
576 		goto out;
577 
578 	/* read current mtu value from device */
579 	err = usbnet_read_cmd(dev, USB_CDC_GET_MAX_DATAGRAM_SIZE,
580 			      USB_TYPE_CLASS | USB_DIR_IN | USB_RECIP_INTERFACE,
581 			      0, iface_no, &max_datagram_size, 2);
582 	if (err < 0) {
583 		dev_dbg(&dev->intf->dev, "GET_MAX_DATAGRAM_SIZE failed\n");
584 		goto out;
585 	}
586 
587 	if (le16_to_cpu(max_datagram_size) == ctx->max_datagram_size)
588 		goto out;
589 
590 	max_datagram_size = cpu_to_le16(ctx->max_datagram_size);
591 	err = usbnet_write_cmd(dev, USB_CDC_SET_MAX_DATAGRAM_SIZE,
592 			       USB_TYPE_CLASS | USB_DIR_OUT | USB_RECIP_INTERFACE,
593 			       0, iface_no, &max_datagram_size, 2);
594 	if (err < 0)
595 		dev_dbg(&dev->intf->dev, "SET_MAX_DATAGRAM_SIZE failed\n");
596 
597 out:
598 	/* set MTU to max supported by the device if necessary */
599 	dev->net->mtu = min_t(int, dev->net->mtu, ctx->max_datagram_size - cdc_ncm_eth_hlen(dev));
600 
601 	/* do not exceed operater preferred MTU */
602 	if (ctx->mbim_extended_desc) {
603 		mbim_mtu = le16_to_cpu(ctx->mbim_extended_desc->wMTU);
604 		if (mbim_mtu != 0 && mbim_mtu < dev->net->mtu)
605 			dev->net->mtu = mbim_mtu;
606 	}
607 }
608 
609 static void cdc_ncm_fix_modulus(struct usbnet *dev)
610 {
611 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
612 	u32 val;
613 
614 	/*
615 	 * verify that the structure alignment is:
616 	 * - power of two
617 	 * - not greater than the maximum transmit length
618 	 * - not less than four bytes
619 	 */
620 	val = ctx->tx_ndp_modulus;
621 
622 	if ((val < USB_CDC_NCM_NDP_ALIGN_MIN_SIZE) ||
623 	    (val != ((-val) & val)) || (val >= ctx->tx_max)) {
624 		dev_dbg(&dev->intf->dev, "Using default alignment: 4 bytes\n");
625 		ctx->tx_ndp_modulus = USB_CDC_NCM_NDP_ALIGN_MIN_SIZE;
626 	}
627 
628 	/*
629 	 * verify that the payload alignment is:
630 	 * - power of two
631 	 * - not greater than the maximum transmit length
632 	 * - not less than four bytes
633 	 */
634 	val = ctx->tx_modulus;
635 
636 	if ((val < USB_CDC_NCM_NDP_ALIGN_MIN_SIZE) ||
637 	    (val != ((-val) & val)) || (val >= ctx->tx_max)) {
638 		dev_dbg(&dev->intf->dev, "Using default transmit modulus: 4 bytes\n");
639 		ctx->tx_modulus = USB_CDC_NCM_NDP_ALIGN_MIN_SIZE;
640 	}
641 
642 	/* verify the payload remainder */
643 	if (ctx->tx_remainder >= ctx->tx_modulus) {
644 		dev_dbg(&dev->intf->dev, "Using default transmit remainder: 0 bytes\n");
645 		ctx->tx_remainder = 0;
646 	}
647 
648 	/* adjust TX-remainder according to NCM specification. */
649 	ctx->tx_remainder = ((ctx->tx_remainder - cdc_ncm_eth_hlen(dev)) &
650 			     (ctx->tx_modulus - 1));
651 }
652 
653 static int cdc_ncm_setup(struct usbnet *dev)
654 {
655 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
656 	u32 def_rx, def_tx;
657 
658 	/* be conservative when selecting intial buffer size to
659 	 * increase the number of hosts this will work for
660 	 */
661 	def_rx = min_t(u32, CDC_NCM_NTB_DEF_SIZE_RX,
662 		       le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize));
663 	def_tx = min_t(u32, CDC_NCM_NTB_DEF_SIZE_TX,
664 		       le32_to_cpu(ctx->ncm_parm.dwNtbOutMaxSize));
665 
666 	/* clamp rx_max and tx_max and inform device */
667 	cdc_ncm_update_rxtx_max(dev, def_rx, def_tx);
668 
669 	/* sanitize the modulus and remainder values */
670 	cdc_ncm_fix_modulus(dev);
671 
672 	/* set max datagram size */
673 	cdc_ncm_set_dgram_size(dev, cdc_ncm_max_dgram_size(dev));
674 	return 0;
675 }
676 
677 static void
678 cdc_ncm_find_endpoints(struct usbnet *dev, struct usb_interface *intf)
679 {
680 	struct usb_host_endpoint *e, *in = NULL, *out = NULL;
681 	u8 ep;
682 
683 	for (ep = 0; ep < intf->cur_altsetting->desc.bNumEndpoints; ep++) {
684 		e = intf->cur_altsetting->endpoint + ep;
685 
686 		/* ignore endpoints which cannot transfer data */
687 		if (!usb_endpoint_maxp(&e->desc))
688 			continue;
689 
690 		switch (e->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
691 		case USB_ENDPOINT_XFER_INT:
692 			if (usb_endpoint_dir_in(&e->desc)) {
693 				if (!dev->status)
694 					dev->status = e;
695 			}
696 			break;
697 
698 		case USB_ENDPOINT_XFER_BULK:
699 			if (usb_endpoint_dir_in(&e->desc)) {
700 				if (!in)
701 					in = e;
702 			} else {
703 				if (!out)
704 					out = e;
705 			}
706 			break;
707 
708 		default:
709 			break;
710 		}
711 	}
712 	if (in && !dev->in)
713 		dev->in = usb_rcvbulkpipe(dev->udev,
714 					  in->desc.bEndpointAddress &
715 					  USB_ENDPOINT_NUMBER_MASK);
716 	if (out && !dev->out)
717 		dev->out = usb_sndbulkpipe(dev->udev,
718 					   out->desc.bEndpointAddress &
719 					   USB_ENDPOINT_NUMBER_MASK);
720 }
721 
722 static void cdc_ncm_free(struct cdc_ncm_ctx *ctx)
723 {
724 	if (ctx == NULL)
725 		return;
726 
727 	if (ctx->tx_rem_skb != NULL) {
728 		dev_kfree_skb_any(ctx->tx_rem_skb);
729 		ctx->tx_rem_skb = NULL;
730 	}
731 
732 	if (ctx->tx_curr_skb != NULL) {
733 		dev_kfree_skb_any(ctx->tx_curr_skb);
734 		ctx->tx_curr_skb = NULL;
735 	}
736 
737 	kfree(ctx->delayed_ndp16);
738 
739 	kfree(ctx);
740 }
741 
742 /* we need to override the usbnet change_mtu ndo for two reasons:
743  *  - respect the negotiated maximum datagram size
744  *  - avoid unwanted changes to rx and tx buffers
745  */
746 int cdc_ncm_change_mtu(struct net_device *net, int new_mtu)
747 {
748 	struct usbnet *dev = netdev_priv(net);
749 
750 	net->mtu = new_mtu;
751 	cdc_ncm_set_dgram_size(dev, new_mtu + cdc_ncm_eth_hlen(dev));
752 
753 	return 0;
754 }
755 EXPORT_SYMBOL_GPL(cdc_ncm_change_mtu);
756 
757 static const struct net_device_ops cdc_ncm_netdev_ops = {
758 	.ndo_open	     = usbnet_open,
759 	.ndo_stop	     = usbnet_stop,
760 	.ndo_start_xmit	     = usbnet_start_xmit,
761 	.ndo_tx_timeout	     = usbnet_tx_timeout,
762 	.ndo_get_stats64     = usbnet_get_stats64,
763 	.ndo_change_mtu	     = cdc_ncm_change_mtu,
764 	.ndo_set_mac_address = eth_mac_addr,
765 	.ndo_validate_addr   = eth_validate_addr,
766 };
767 
768 int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting, int drvflags)
769 {
770 	struct cdc_ncm_ctx *ctx;
771 	struct usb_driver *driver;
772 	u8 *buf;
773 	int len;
774 	int temp;
775 	int err;
776 	u8 iface_no;
777 	struct usb_cdc_parsed_header hdr;
778 	__le16 curr_ntb_format;
779 
780 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
781 	if (!ctx)
782 		return -ENOMEM;
783 
784 	hrtimer_init(&ctx->tx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
785 	ctx->tx_timer.function = &cdc_ncm_tx_timer_cb;
786 	tasklet_init(&ctx->bh, cdc_ncm_txpath_bh, (unsigned long)dev);
787 	atomic_set(&ctx->stop, 0);
788 	spin_lock_init(&ctx->mtx);
789 
790 	/* store ctx pointer in device data field */
791 	dev->data[0] = (unsigned long)ctx;
792 
793 	/* only the control interface can be successfully probed */
794 	ctx->control = intf;
795 
796 	/* get some pointers */
797 	driver = driver_of(intf);
798 	buf = intf->cur_altsetting->extra;
799 	len = intf->cur_altsetting->extralen;
800 
801 	/* parse through descriptors associated with control interface */
802 	cdc_parse_cdc_header(&hdr, intf, buf, len);
803 
804 	if (hdr.usb_cdc_union_desc)
805 		ctx->data = usb_ifnum_to_if(dev->udev,
806 					    hdr.usb_cdc_union_desc->bSlaveInterface0);
807 	ctx->ether_desc = hdr.usb_cdc_ether_desc;
808 	ctx->func_desc = hdr.usb_cdc_ncm_desc;
809 	ctx->mbim_desc = hdr.usb_cdc_mbim_desc;
810 	ctx->mbim_extended_desc = hdr.usb_cdc_mbim_extended_desc;
811 
812 	/* some buggy devices have an IAD but no CDC Union */
813 	if (!hdr.usb_cdc_union_desc && intf->intf_assoc && intf->intf_assoc->bInterfaceCount == 2) {
814 		ctx->data = usb_ifnum_to_if(dev->udev, intf->cur_altsetting->desc.bInterfaceNumber + 1);
815 		dev_dbg(&intf->dev, "CDC Union missing - got slave from IAD\n");
816 	}
817 
818 	/* check if we got everything */
819 	if (!ctx->data) {
820 		dev_dbg(&intf->dev, "CDC Union missing and no IAD found\n");
821 		goto error;
822 	}
823 	if (cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting)) {
824 		if (!ctx->mbim_desc) {
825 			dev_dbg(&intf->dev, "MBIM functional descriptor missing\n");
826 			goto error;
827 		}
828 	} else {
829 		if (!ctx->ether_desc || !ctx->func_desc) {
830 			dev_dbg(&intf->dev, "NCM or ECM functional descriptors missing\n");
831 			goto error;
832 		}
833 	}
834 
835 	/* claim data interface, if different from control */
836 	if (ctx->data != ctx->control) {
837 		temp = usb_driver_claim_interface(driver, ctx->data, dev);
838 		if (temp) {
839 			dev_dbg(&intf->dev, "failed to claim data intf\n");
840 			goto error;
841 		}
842 	}
843 
844 	iface_no = ctx->data->cur_altsetting->desc.bInterfaceNumber;
845 
846 	/* Device-specific flags */
847 	ctx->drvflags = drvflags;
848 
849 	/* Reset data interface. Some devices will not reset properly
850 	 * unless they are configured first.  Toggle the altsetting to
851 	 * force a reset.
852 	 * Some other devices do not work properly with this procedure
853 	 * that can be avoided using quirk CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE
854 	 */
855 	if (!(ctx->drvflags & CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE))
856 		usb_set_interface(dev->udev, iface_no, data_altsetting);
857 
858 	temp = usb_set_interface(dev->udev, iface_no, 0);
859 	if (temp) {
860 		dev_dbg(&intf->dev, "set interface failed\n");
861 		goto error2;
862 	}
863 
864 	/* initialize basic device settings */
865 	if (cdc_ncm_init(dev))
866 		goto error2;
867 
868 	/* Some firmwares need a pause here or they will silently fail
869 	 * to set up the interface properly.  This value was decided
870 	 * empirically on a Sierra Wireless MC7455 running 02.08.02.00
871 	 * firmware.
872 	 */
873 	usleep_range(10000, 20000);
874 
875 	/* configure data interface */
876 	temp = usb_set_interface(dev->udev, iface_no, data_altsetting);
877 	if (temp) {
878 		dev_dbg(&intf->dev, "set interface failed\n");
879 		goto error2;
880 	}
881 
882 	/*
883 	 * Some Huawei devices have been observed to come out of reset in NDP32 mode.
884 	 * Let's check if this is the case, and set the device to NDP16 mode again if
885 	 * needed.
886 	*/
887 	if (ctx->drvflags & CDC_NCM_FLAG_RESET_NTB16) {
888 		err = usbnet_read_cmd(dev, USB_CDC_GET_NTB_FORMAT,
889 				      USB_TYPE_CLASS | USB_DIR_IN | USB_RECIP_INTERFACE,
890 				      0, iface_no, &curr_ntb_format, 2);
891 		if (err < 0) {
892 			goto error2;
893 		}
894 
895 		if (curr_ntb_format == cpu_to_le16(USB_CDC_NCM_NTB32_FORMAT)) {
896 			dev_info(&intf->dev, "resetting NTB format to 16-bit");
897 			err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_FORMAT,
898 					       USB_TYPE_CLASS | USB_DIR_OUT
899 					       | USB_RECIP_INTERFACE,
900 					       USB_CDC_NCM_NTB16_FORMAT,
901 					       iface_no, NULL, 0);
902 
903 			if (err < 0)
904 				goto error2;
905 		}
906 	}
907 
908 	cdc_ncm_find_endpoints(dev, ctx->data);
909 	cdc_ncm_find_endpoints(dev, ctx->control);
910 	if (!dev->in || !dev->out || !dev->status) {
911 		dev_dbg(&intf->dev, "failed to collect endpoints\n");
912 		goto error2;
913 	}
914 
915 	usb_set_intfdata(ctx->data, dev);
916 	usb_set_intfdata(ctx->control, dev);
917 
918 	if (ctx->ether_desc) {
919 		temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
920 		if (temp) {
921 			dev_dbg(&intf->dev, "failed to get mac address\n");
922 			goto error2;
923 		}
924 		dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net->dev_addr);
925 	}
926 
927 	/* finish setting up the device specific data */
928 	cdc_ncm_setup(dev);
929 
930 	/* Allocate the delayed NDP if needed. */
931 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
932 		ctx->delayed_ndp16 = kzalloc(ctx->max_ndp_size, GFP_KERNEL);
933 		if (!ctx->delayed_ndp16)
934 			goto error2;
935 		dev_info(&intf->dev, "NDP will be placed at end of frame for this device.");
936 	}
937 
938 	/* override ethtool_ops */
939 	dev->net->ethtool_ops = &cdc_ncm_ethtool_ops;
940 
941 	/* add our sysfs attrs */
942 	dev->net->sysfs_groups[0] = &cdc_ncm_sysfs_attr_group;
943 
944 	/* must handle MTU changes */
945 	dev->net->netdev_ops = &cdc_ncm_netdev_ops;
946 	dev->net->max_mtu = cdc_ncm_max_dgram_size(dev) - cdc_ncm_eth_hlen(dev);
947 
948 	return 0;
949 
950 error2:
951 	usb_set_intfdata(ctx->control, NULL);
952 	usb_set_intfdata(ctx->data, NULL);
953 	if (ctx->data != ctx->control)
954 		usb_driver_release_interface(driver, ctx->data);
955 error:
956 	cdc_ncm_free((struct cdc_ncm_ctx *)dev->data[0]);
957 	dev->data[0] = 0;
958 	dev_info(&intf->dev, "bind() failure\n");
959 	return -ENODEV;
960 }
961 EXPORT_SYMBOL_GPL(cdc_ncm_bind_common);
962 
963 void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf)
964 {
965 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
966 	struct usb_driver *driver = driver_of(intf);
967 
968 	if (ctx == NULL)
969 		return;		/* no setup */
970 
971 	atomic_set(&ctx->stop, 1);
972 
973 	hrtimer_cancel(&ctx->tx_timer);
974 
975 	tasklet_kill(&ctx->bh);
976 
977 	/* handle devices with combined control and data interface */
978 	if (ctx->control == ctx->data)
979 		ctx->data = NULL;
980 
981 	/* disconnect master --> disconnect slave */
982 	if (intf == ctx->control && ctx->data) {
983 		usb_set_intfdata(ctx->data, NULL);
984 		usb_driver_release_interface(driver, ctx->data);
985 		ctx->data = NULL;
986 
987 	} else if (intf == ctx->data && ctx->control) {
988 		usb_set_intfdata(ctx->control, NULL);
989 		usb_driver_release_interface(driver, ctx->control);
990 		ctx->control = NULL;
991 	}
992 
993 	usb_set_intfdata(intf, NULL);
994 	cdc_ncm_free(ctx);
995 }
996 EXPORT_SYMBOL_GPL(cdc_ncm_unbind);
997 
998 /* Return the number of the MBIM control interface altsetting iff it
999  * is preferred and available,
1000  */
1001 u8 cdc_ncm_select_altsetting(struct usb_interface *intf)
1002 {
1003 	struct usb_host_interface *alt;
1004 
1005 	/* The MBIM spec defines a NCM compatible default altsetting,
1006 	 * which we may have matched:
1007 	 *
1008 	 *  "Functions that implement both NCM 1.0 and MBIM (an
1009 	 *   “NCM/MBIM function”) according to this recommendation
1010 	 *   shall provide two alternate settings for the
1011 	 *   Communication Interface.  Alternate setting 0, and the
1012 	 *   associated class and endpoint descriptors, shall be
1013 	 *   constructed according to the rules given for the
1014 	 *   Communication Interface in section 5 of [USBNCM10].
1015 	 *   Alternate setting 1, and the associated class and
1016 	 *   endpoint descriptors, shall be constructed according to
1017 	 *   the rules given in section 6 (USB Device Model) of this
1018 	 *   specification."
1019 	 */
1020 	if (intf->num_altsetting < 2)
1021 		return intf->cur_altsetting->desc.bAlternateSetting;
1022 
1023 	if (prefer_mbim) {
1024 		alt = usb_altnum_to_altsetting(intf, CDC_NCM_COMM_ALTSETTING_MBIM);
1025 		if (alt && cdc_ncm_comm_intf_is_mbim(alt))
1026 			return CDC_NCM_COMM_ALTSETTING_MBIM;
1027 	}
1028 	return CDC_NCM_COMM_ALTSETTING_NCM;
1029 }
1030 EXPORT_SYMBOL_GPL(cdc_ncm_select_altsetting);
1031 
1032 static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
1033 {
1034 	/* MBIM backwards compatible function? */
1035 	if (cdc_ncm_select_altsetting(intf) != CDC_NCM_COMM_ALTSETTING_NCM)
1036 		return -ENODEV;
1037 
1038 	/* The NCM data altsetting is fixed, so we hard-coded it.
1039 	 * Additionally, generic NCM devices are assumed to accept arbitrarily
1040 	 * placed NDP.
1041 	 */
1042 	return cdc_ncm_bind_common(dev, intf, CDC_NCM_DATA_ALTSETTING_NCM, 0);
1043 }
1044 
1045 static void cdc_ncm_align_tail(struct sk_buff *skb, size_t modulus, size_t remainder, size_t max)
1046 {
1047 	size_t align = ALIGN(skb->len, modulus) - skb->len + remainder;
1048 
1049 	if (skb->len + align > max)
1050 		align = max - skb->len;
1051 	if (align && skb_tailroom(skb) >= align)
1052 		skb_put_zero(skb, align);
1053 }
1054 
1055 /* return a pointer to a valid struct usb_cdc_ncm_ndp16 of type sign, possibly
1056  * allocating a new one within skb
1057  */
1058 static struct usb_cdc_ncm_ndp16 *cdc_ncm_ndp(struct cdc_ncm_ctx *ctx, struct sk_buff *skb, __le32 sign, size_t reserve)
1059 {
1060 	struct usb_cdc_ncm_ndp16 *ndp16 = NULL;
1061 	struct usb_cdc_ncm_nth16 *nth16 = (void *)skb->data;
1062 	size_t ndpoffset = le16_to_cpu(nth16->wNdpIndex);
1063 
1064 	/* If NDP should be moved to the end of the NCM package, we can't follow the
1065 	* NTH16 header as we would normally do. NDP isn't written to the SKB yet, and
1066 	* the wNdpIndex field in the header is actually not consistent with reality. It will be later.
1067 	*/
1068 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
1069 		if (ctx->delayed_ndp16->dwSignature == sign)
1070 			return ctx->delayed_ndp16;
1071 
1072 		/* We can only push a single NDP to the end. Return
1073 		 * NULL to send what we've already got and queue this
1074 		 * skb for later.
1075 		 */
1076 		else if (ctx->delayed_ndp16->dwSignature)
1077 			return NULL;
1078 	}
1079 
1080 	/* follow the chain of NDPs, looking for a match */
1081 	while (ndpoffset) {
1082 		ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb->data + ndpoffset);
1083 		if  (ndp16->dwSignature == sign)
1084 			return ndp16;
1085 		ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
1086 	}
1087 
1088 	/* align new NDP */
1089 	if (!(ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))
1090 		cdc_ncm_align_tail(skb, ctx->tx_ndp_modulus, 0, ctx->tx_curr_size);
1091 
1092 	/* verify that there is room for the NDP and the datagram (reserve) */
1093 	if ((ctx->tx_curr_size - skb->len - reserve) < ctx->max_ndp_size)
1094 		return NULL;
1095 
1096 	/* link to it */
1097 	if (ndp16)
1098 		ndp16->wNextNdpIndex = cpu_to_le16(skb->len);
1099 	else
1100 		nth16->wNdpIndex = cpu_to_le16(skb->len);
1101 
1102 	/* push a new empty NDP */
1103 	if (!(ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))
1104 		ndp16 = skb_put_zero(skb, ctx->max_ndp_size);
1105 	else
1106 		ndp16 = ctx->delayed_ndp16;
1107 
1108 	ndp16->dwSignature = sign;
1109 	ndp16->wLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_ndp16) + sizeof(struct usb_cdc_ncm_dpe16));
1110 	return ndp16;
1111 }
1112 
1113 struct sk_buff *
1114 cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign)
1115 {
1116 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
1117 	struct usb_cdc_ncm_nth16 *nth16;
1118 	struct usb_cdc_ncm_ndp16 *ndp16;
1119 	struct sk_buff *skb_out;
1120 	u16 n = 0, index, ndplen;
1121 	u8 ready2send = 0;
1122 	u32 delayed_ndp_size;
1123 	size_t padding_count;
1124 
1125 	/* When our NDP gets written in cdc_ncm_ndp(), then skb_out->len gets updated
1126 	 * accordingly. Otherwise, we should check here.
1127 	 */
1128 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END)
1129 		delayed_ndp_size = ALIGN(ctx->max_ndp_size, ctx->tx_ndp_modulus);
1130 	else
1131 		delayed_ndp_size = 0;
1132 
1133 	/* if there is a remaining skb, it gets priority */
1134 	if (skb != NULL) {
1135 		swap(skb, ctx->tx_rem_skb);
1136 		swap(sign, ctx->tx_rem_sign);
1137 	} else {
1138 		ready2send = 1;
1139 	}
1140 
1141 	/* check if we are resuming an OUT skb */
1142 	skb_out = ctx->tx_curr_skb;
1143 
1144 	/* allocate a new OUT skb */
1145 	if (!skb_out) {
1146 		if (ctx->tx_low_mem_val == 0) {
1147 			ctx->tx_curr_size = ctx->tx_max;
1148 			skb_out = alloc_skb(ctx->tx_curr_size, GFP_ATOMIC);
1149 			/* If the memory allocation fails we will wait longer
1150 			 * each time before attempting another full size
1151 			 * allocation again to not overload the system
1152 			 * further.
1153 			 */
1154 			if (skb_out == NULL) {
1155 				ctx->tx_low_mem_max_cnt = min(ctx->tx_low_mem_max_cnt + 1,
1156 							      (unsigned)CDC_NCM_LOW_MEM_MAX_CNT);
1157 				ctx->tx_low_mem_val = ctx->tx_low_mem_max_cnt;
1158 			}
1159 		}
1160 		if (skb_out == NULL) {
1161 			/* See if a very small allocation is possible.
1162 			 * We will send this packet immediately and hope
1163 			 * that there is more memory available later.
1164 			 */
1165 			if (skb)
1166 				ctx->tx_curr_size = max(skb->len,
1167 					(u32)USB_CDC_NCM_NTB_MIN_OUT_SIZE);
1168 			else
1169 				ctx->tx_curr_size = USB_CDC_NCM_NTB_MIN_OUT_SIZE;
1170 			skb_out = alloc_skb(ctx->tx_curr_size, GFP_ATOMIC);
1171 
1172 			/* No allocation possible so we will abort */
1173 			if (skb_out == NULL) {
1174 				if (skb != NULL) {
1175 					dev_kfree_skb_any(skb);
1176 					dev->net->stats.tx_dropped++;
1177 				}
1178 				goto exit_no_skb;
1179 			}
1180 			ctx->tx_low_mem_val--;
1181 		}
1182 		/* fill out the initial 16-bit NTB header */
1183 		nth16 = skb_put_zero(skb_out, sizeof(struct usb_cdc_ncm_nth16));
1184 		nth16->dwSignature = cpu_to_le32(USB_CDC_NCM_NTH16_SIGN);
1185 		nth16->wHeaderLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_nth16));
1186 		nth16->wSequence = cpu_to_le16(ctx->tx_seq++);
1187 
1188 		/* count total number of frames in this NTB */
1189 		ctx->tx_curr_frame_num = 0;
1190 
1191 		/* recent payload counter for this skb_out */
1192 		ctx->tx_curr_frame_payload = 0;
1193 	}
1194 
1195 	for (n = ctx->tx_curr_frame_num; n < ctx->tx_max_datagrams; n++) {
1196 		/* send any remaining skb first */
1197 		if (skb == NULL) {
1198 			skb = ctx->tx_rem_skb;
1199 			sign = ctx->tx_rem_sign;
1200 			ctx->tx_rem_skb = NULL;
1201 
1202 			/* check for end of skb */
1203 			if (skb == NULL)
1204 				break;
1205 		}
1206 
1207 		/* get the appropriate NDP for this skb */
1208 		ndp16 = cdc_ncm_ndp(ctx, skb_out, sign, skb->len + ctx->tx_modulus + ctx->tx_remainder);
1209 
1210 		/* align beginning of next frame */
1211 		cdc_ncm_align_tail(skb_out,  ctx->tx_modulus, ctx->tx_remainder, ctx->tx_curr_size);
1212 
1213 		/* check if we had enough room left for both NDP and frame */
1214 		if (!ndp16 || skb_out->len + skb->len + delayed_ndp_size > ctx->tx_curr_size) {
1215 			if (n == 0) {
1216 				/* won't fit, MTU problem? */
1217 				dev_kfree_skb_any(skb);
1218 				skb = NULL;
1219 				dev->net->stats.tx_dropped++;
1220 			} else {
1221 				/* no room for skb - store for later */
1222 				if (ctx->tx_rem_skb != NULL) {
1223 					dev_kfree_skb_any(ctx->tx_rem_skb);
1224 					dev->net->stats.tx_dropped++;
1225 				}
1226 				ctx->tx_rem_skb = skb;
1227 				ctx->tx_rem_sign = sign;
1228 				skb = NULL;
1229 				ready2send = 1;
1230 				ctx->tx_reason_ntb_full++;	/* count reason for transmitting */
1231 			}
1232 			break;
1233 		}
1234 
1235 		/* calculate frame number withing this NDP */
1236 		ndplen = le16_to_cpu(ndp16->wLength);
1237 		index = (ndplen - sizeof(struct usb_cdc_ncm_ndp16)) / sizeof(struct usb_cdc_ncm_dpe16) - 1;
1238 
1239 		/* OK, add this skb */
1240 		ndp16->dpe16[index].wDatagramLength = cpu_to_le16(skb->len);
1241 		ndp16->dpe16[index].wDatagramIndex = cpu_to_le16(skb_out->len);
1242 		ndp16->wLength = cpu_to_le16(ndplen + sizeof(struct usb_cdc_ncm_dpe16));
1243 		skb_put_data(skb_out, skb->data, skb->len);
1244 		ctx->tx_curr_frame_payload += skb->len;	/* count real tx payload data */
1245 		dev_kfree_skb_any(skb);
1246 		skb = NULL;
1247 
1248 		/* send now if this NDP is full */
1249 		if (index >= CDC_NCM_DPT_DATAGRAMS_MAX) {
1250 			ready2send = 1;
1251 			ctx->tx_reason_ndp_full++;	/* count reason for transmitting */
1252 			break;
1253 		}
1254 	}
1255 
1256 	/* free up any dangling skb */
1257 	if (skb != NULL) {
1258 		dev_kfree_skb_any(skb);
1259 		skb = NULL;
1260 		dev->net->stats.tx_dropped++;
1261 	}
1262 
1263 	ctx->tx_curr_frame_num = n;
1264 
1265 	if (n == 0) {
1266 		/* wait for more frames */
1267 		/* push variables */
1268 		ctx->tx_curr_skb = skb_out;
1269 		goto exit_no_skb;
1270 
1271 	} else if ((n < ctx->tx_max_datagrams) && (ready2send == 0) && (ctx->timer_interval > 0)) {
1272 		/* wait for more frames */
1273 		/* push variables */
1274 		ctx->tx_curr_skb = skb_out;
1275 		/* set the pending count */
1276 		if (n < CDC_NCM_RESTART_TIMER_DATAGRAM_CNT)
1277 			ctx->tx_timer_pending = CDC_NCM_TIMER_PENDING_CNT;
1278 		goto exit_no_skb;
1279 
1280 	} else {
1281 		if (n == ctx->tx_max_datagrams)
1282 			ctx->tx_reason_max_datagram++;	/* count reason for transmitting */
1283 		/* frame goes out */
1284 		/* variables will be reset at next call */
1285 	}
1286 
1287 	/* If requested, put NDP at end of frame. */
1288 	if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
1289 		nth16 = (struct usb_cdc_ncm_nth16 *)skb_out->data;
1290 		cdc_ncm_align_tail(skb_out, ctx->tx_ndp_modulus, 0, ctx->tx_curr_size - ctx->max_ndp_size);
1291 		nth16->wNdpIndex = cpu_to_le16(skb_out->len);
1292 		skb_put_data(skb_out, ctx->delayed_ndp16, ctx->max_ndp_size);
1293 
1294 		/* Zero out delayed NDP - signature checking will naturally fail. */
1295 		ndp16 = memset(ctx->delayed_ndp16, 0, ctx->max_ndp_size);
1296 	}
1297 
1298 	/* If collected data size is less or equal ctx->min_tx_pkt
1299 	 * bytes, we send buffers as it is. If we get more data, it
1300 	 * would be more efficient for USB HS mobile device with DMA
1301 	 * engine to receive a full size NTB, than canceling DMA
1302 	 * transfer and receiving a short packet.
1303 	 *
1304 	 * This optimization support is pointless if we end up sending
1305 	 * a ZLP after full sized NTBs.
1306 	 */
1307 	if (!(dev->driver_info->flags & FLAG_SEND_ZLP) &&
1308 	    skb_out->len > ctx->min_tx_pkt) {
1309 		padding_count = ctx->tx_curr_size - skb_out->len;
1310 		skb_put_zero(skb_out, padding_count);
1311 	} else if (skb_out->len < ctx->tx_curr_size &&
1312 		   (skb_out->len % dev->maxpacket) == 0) {
1313 		skb_put_u8(skb_out, 0);	/* force short packet */
1314 	}
1315 
1316 	/* set final frame length */
1317 	nth16 = (struct usb_cdc_ncm_nth16 *)skb_out->data;
1318 	nth16->wBlockLength = cpu_to_le16(skb_out->len);
1319 
1320 	/* return skb */
1321 	ctx->tx_curr_skb = NULL;
1322 
1323 	/* keep private stats: framing overhead and number of NTBs */
1324 	ctx->tx_overhead += skb_out->len - ctx->tx_curr_frame_payload;
1325 	ctx->tx_ntbs++;
1326 
1327 	/* usbnet will count all the framing overhead by default.
1328 	 * Adjust the stats so that the tx_bytes counter show real
1329 	 * payload data instead.
1330 	 */
1331 	usbnet_set_skb_tx_stats(skb_out, n,
1332 				(long)ctx->tx_curr_frame_payload - skb_out->len);
1333 
1334 	return skb_out;
1335 
1336 exit_no_skb:
1337 	/* Start timer, if there is a remaining non-empty skb */
1338 	if (ctx->tx_curr_skb != NULL && n > 0)
1339 		cdc_ncm_tx_timeout_start(ctx);
1340 	return NULL;
1341 }
1342 EXPORT_SYMBOL_GPL(cdc_ncm_fill_tx_frame);
1343 
1344 static void cdc_ncm_tx_timeout_start(struct cdc_ncm_ctx *ctx)
1345 {
1346 	/* start timer, if not already started */
1347 	if (!(hrtimer_active(&ctx->tx_timer) || atomic_read(&ctx->stop)))
1348 		hrtimer_start(&ctx->tx_timer,
1349 				ctx->timer_interval,
1350 				HRTIMER_MODE_REL);
1351 }
1352 
1353 static enum hrtimer_restart cdc_ncm_tx_timer_cb(struct hrtimer *timer)
1354 {
1355 	struct cdc_ncm_ctx *ctx =
1356 			container_of(timer, struct cdc_ncm_ctx, tx_timer);
1357 
1358 	if (!atomic_read(&ctx->stop))
1359 		tasklet_schedule(&ctx->bh);
1360 	return HRTIMER_NORESTART;
1361 }
1362 
1363 static void cdc_ncm_txpath_bh(unsigned long param)
1364 {
1365 	struct usbnet *dev = (struct usbnet *)param;
1366 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
1367 
1368 	spin_lock_bh(&ctx->mtx);
1369 	if (ctx->tx_timer_pending != 0) {
1370 		ctx->tx_timer_pending--;
1371 		cdc_ncm_tx_timeout_start(ctx);
1372 		spin_unlock_bh(&ctx->mtx);
1373 	} else if (dev->net != NULL) {
1374 		ctx->tx_reason_timeout++;	/* count reason for transmitting */
1375 		spin_unlock_bh(&ctx->mtx);
1376 		netif_tx_lock_bh(dev->net);
1377 		usbnet_start_xmit(NULL, dev->net);
1378 		netif_tx_unlock_bh(dev->net);
1379 	} else {
1380 		spin_unlock_bh(&ctx->mtx);
1381 	}
1382 }
1383 
1384 struct sk_buff *
1385 cdc_ncm_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
1386 {
1387 	struct sk_buff *skb_out;
1388 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
1389 
1390 	/*
1391 	 * The Ethernet API we are using does not support transmitting
1392 	 * multiple Ethernet frames in a single call. This driver will
1393 	 * accumulate multiple Ethernet frames and send out a larger
1394 	 * USB frame when the USB buffer is full or when a single jiffies
1395 	 * timeout happens.
1396 	 */
1397 	if (ctx == NULL)
1398 		goto error;
1399 
1400 	spin_lock_bh(&ctx->mtx);
1401 	skb_out = cdc_ncm_fill_tx_frame(dev, skb, cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN));
1402 	spin_unlock_bh(&ctx->mtx);
1403 	return skb_out;
1404 
1405 error:
1406 	if (skb != NULL)
1407 		dev_kfree_skb_any(skb);
1408 
1409 	return NULL;
1410 }
1411 EXPORT_SYMBOL_GPL(cdc_ncm_tx_fixup);
1412 
1413 /* verify NTB header and return offset of first NDP, or negative error */
1414 int cdc_ncm_rx_verify_nth16(struct cdc_ncm_ctx *ctx, struct sk_buff *skb_in)
1415 {
1416 	struct usbnet *dev = netdev_priv(skb_in->dev);
1417 	struct usb_cdc_ncm_nth16 *nth16;
1418 	int len;
1419 	int ret = -EINVAL;
1420 
1421 	if (ctx == NULL)
1422 		goto error;
1423 
1424 	if (skb_in->len < (sizeof(struct usb_cdc_ncm_nth16) +
1425 					sizeof(struct usb_cdc_ncm_ndp16))) {
1426 		netif_dbg(dev, rx_err, dev->net, "frame too short\n");
1427 		goto error;
1428 	}
1429 
1430 	nth16 = (struct usb_cdc_ncm_nth16 *)skb_in->data;
1431 
1432 	if (nth16->dwSignature != cpu_to_le32(USB_CDC_NCM_NTH16_SIGN)) {
1433 		netif_dbg(dev, rx_err, dev->net,
1434 			  "invalid NTH16 signature <%#010x>\n",
1435 			  le32_to_cpu(nth16->dwSignature));
1436 		goto error;
1437 	}
1438 
1439 	len = le16_to_cpu(nth16->wBlockLength);
1440 	if (len > ctx->rx_max) {
1441 		netif_dbg(dev, rx_err, dev->net,
1442 			  "unsupported NTB block length %u/%u\n", len,
1443 			  ctx->rx_max);
1444 		goto error;
1445 	}
1446 
1447 	if ((ctx->rx_seq + 1) != le16_to_cpu(nth16->wSequence) &&
1448 	    (ctx->rx_seq || le16_to_cpu(nth16->wSequence)) &&
1449 	    !((ctx->rx_seq == 0xffff) && !le16_to_cpu(nth16->wSequence))) {
1450 		netif_dbg(dev, rx_err, dev->net,
1451 			  "sequence number glitch prev=%d curr=%d\n",
1452 			  ctx->rx_seq, le16_to_cpu(nth16->wSequence));
1453 	}
1454 	ctx->rx_seq = le16_to_cpu(nth16->wSequence);
1455 
1456 	ret = le16_to_cpu(nth16->wNdpIndex);
1457 error:
1458 	return ret;
1459 }
1460 EXPORT_SYMBOL_GPL(cdc_ncm_rx_verify_nth16);
1461 
1462 /* verify NDP header and return number of datagrams, or negative error */
1463 int cdc_ncm_rx_verify_ndp16(struct sk_buff *skb_in, int ndpoffset)
1464 {
1465 	struct usbnet *dev = netdev_priv(skb_in->dev);
1466 	struct usb_cdc_ncm_ndp16 *ndp16;
1467 	int ret = -EINVAL;
1468 
1469 	if ((ndpoffset + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len) {
1470 		netif_dbg(dev, rx_err, dev->net, "invalid NDP offset  <%u>\n",
1471 			  ndpoffset);
1472 		goto error;
1473 	}
1474 	ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
1475 
1476 	if (le16_to_cpu(ndp16->wLength) < USB_CDC_NCM_NDP16_LENGTH_MIN) {
1477 		netif_dbg(dev, rx_err, dev->net, "invalid DPT16 length <%u>\n",
1478 			  le16_to_cpu(ndp16->wLength));
1479 		goto error;
1480 	}
1481 
1482 	ret = ((le16_to_cpu(ndp16->wLength) -
1483 					sizeof(struct usb_cdc_ncm_ndp16)) /
1484 					sizeof(struct usb_cdc_ncm_dpe16));
1485 	ret--; /* we process NDP entries except for the last one */
1486 
1487 	if ((sizeof(struct usb_cdc_ncm_ndp16) +
1488 	     ret * (sizeof(struct usb_cdc_ncm_dpe16))) > skb_in->len) {
1489 		netif_dbg(dev, rx_err, dev->net, "Invalid nframes = %d\n", ret);
1490 		ret = -EINVAL;
1491 	}
1492 
1493 error:
1494 	return ret;
1495 }
1496 EXPORT_SYMBOL_GPL(cdc_ncm_rx_verify_ndp16);
1497 
1498 int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
1499 {
1500 	struct sk_buff *skb;
1501 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
1502 	int len;
1503 	int nframes;
1504 	int x;
1505 	int offset;
1506 	struct usb_cdc_ncm_ndp16 *ndp16;
1507 	struct usb_cdc_ncm_dpe16 *dpe16;
1508 	int ndpoffset;
1509 	int loopcount = 50; /* arbitrary max preventing infinite loop */
1510 	u32 payload = 0;
1511 
1512 	ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
1513 	if (ndpoffset < 0)
1514 		goto error;
1515 
1516 next_ndp:
1517 	nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
1518 	if (nframes < 0)
1519 		goto error;
1520 
1521 	ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
1522 
1523 	if (ndp16->dwSignature != cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN)) {
1524 		netif_dbg(dev, rx_err, dev->net,
1525 			  "invalid DPT16 signature <%#010x>\n",
1526 			  le32_to_cpu(ndp16->dwSignature));
1527 		goto err_ndp;
1528 	}
1529 	dpe16 = ndp16->dpe16;
1530 
1531 	for (x = 0; x < nframes; x++, dpe16++) {
1532 		offset = le16_to_cpu(dpe16->wDatagramIndex);
1533 		len = le16_to_cpu(dpe16->wDatagramLength);
1534 
1535 		/*
1536 		 * CDC NCM ch. 3.7
1537 		 * All entries after first NULL entry are to be ignored
1538 		 */
1539 		if ((offset == 0) || (len == 0)) {
1540 			if (!x)
1541 				goto err_ndp; /* empty NTB */
1542 			break;
1543 		}
1544 
1545 		/* sanity checking */
1546 		if (((offset + len) > skb_in->len) ||
1547 				(len > ctx->rx_max) || (len < ETH_HLEN)) {
1548 			netif_dbg(dev, rx_err, dev->net,
1549 				  "invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
1550 				  x, offset, len, skb_in);
1551 			if (!x)
1552 				goto err_ndp;
1553 			break;
1554 
1555 		} else {
1556 			/* create a fresh copy to reduce truesize */
1557 			skb = netdev_alloc_skb_ip_align(dev->net,  len);
1558 			if (!skb)
1559 				goto error;
1560 			skb_put_data(skb, skb_in->data + offset, len);
1561 			usbnet_skb_return(dev, skb);
1562 			payload += len;	/* count payload bytes in this NTB */
1563 		}
1564 	}
1565 err_ndp:
1566 	/* are there more NDPs to process? */
1567 	ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
1568 	if (ndpoffset && loopcount--)
1569 		goto next_ndp;
1570 
1571 	/* update stats */
1572 	ctx->rx_overhead += skb_in->len - payload;
1573 	ctx->rx_ntbs++;
1574 
1575 	return 1;
1576 error:
1577 	return 0;
1578 }
1579 EXPORT_SYMBOL_GPL(cdc_ncm_rx_fixup);
1580 
1581 static void
1582 cdc_ncm_speed_change(struct usbnet *dev,
1583 		     struct usb_cdc_speed_change *data)
1584 {
1585 	uint32_t rx_speed = le32_to_cpu(data->DLBitRRate);
1586 	uint32_t tx_speed = le32_to_cpu(data->ULBitRate);
1587 
1588 	/*
1589 	 * Currently the USB-NET API does not support reporting the actual
1590 	 * device speed. Do print it instead.
1591 	 */
1592 	if ((tx_speed > 1000000) && (rx_speed > 1000000)) {
1593 		netif_info(dev, link, dev->net,
1594 			   "%u mbit/s downlink %u mbit/s uplink\n",
1595 			   (unsigned int)(rx_speed / 1000000U),
1596 			   (unsigned int)(tx_speed / 1000000U));
1597 	} else {
1598 		netif_info(dev, link, dev->net,
1599 			   "%u kbit/s downlink %u kbit/s uplink\n",
1600 			   (unsigned int)(rx_speed / 1000U),
1601 			   (unsigned int)(tx_speed / 1000U));
1602 	}
1603 }
1604 
1605 static void cdc_ncm_status(struct usbnet *dev, struct urb *urb)
1606 {
1607 	struct usb_cdc_notification *event;
1608 
1609 	if (urb->actual_length < sizeof(*event))
1610 		return;
1611 
1612 	/* test for split data in 8-byte chunks */
1613 	if (test_and_clear_bit(EVENT_STS_SPLIT, &dev->flags)) {
1614 		cdc_ncm_speed_change(dev,
1615 		      (struct usb_cdc_speed_change *)urb->transfer_buffer);
1616 		return;
1617 	}
1618 
1619 	event = urb->transfer_buffer;
1620 
1621 	switch (event->bNotificationType) {
1622 	case USB_CDC_NOTIFY_NETWORK_CONNECTION:
1623 		/*
1624 		 * According to the CDC NCM specification ch.7.1
1625 		 * USB_CDC_NOTIFY_NETWORK_CONNECTION notification shall be
1626 		 * sent by device after USB_CDC_NOTIFY_SPEED_CHANGE.
1627 		 */
1628 		netif_info(dev, link, dev->net,
1629 			   "network connection: %sconnected\n",
1630 			   !!event->wValue ? "" : "dis");
1631 		usbnet_link_change(dev, !!event->wValue, 0);
1632 		break;
1633 
1634 	case USB_CDC_NOTIFY_SPEED_CHANGE:
1635 		if (urb->actual_length < (sizeof(*event) +
1636 					sizeof(struct usb_cdc_speed_change)))
1637 			set_bit(EVENT_STS_SPLIT, &dev->flags);
1638 		else
1639 			cdc_ncm_speed_change(dev,
1640 					     (struct usb_cdc_speed_change *)&event[1]);
1641 		break;
1642 
1643 	default:
1644 		dev_dbg(&dev->udev->dev,
1645 			"NCM: unexpected notification 0x%02x!\n",
1646 			event->bNotificationType);
1647 		break;
1648 	}
1649 }
1650 
1651 static const struct driver_info cdc_ncm_info = {
1652 	.description = "CDC NCM",
1653 	.flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
1654 			| FLAG_LINK_INTR,
1655 	.bind = cdc_ncm_bind,
1656 	.unbind = cdc_ncm_unbind,
1657 	.manage_power = usbnet_manage_power,
1658 	.status = cdc_ncm_status,
1659 	.rx_fixup = cdc_ncm_rx_fixup,
1660 	.tx_fixup = cdc_ncm_tx_fixup,
1661 };
1662 
1663 /* Same as cdc_ncm_info, but with FLAG_WWAN */
1664 static const struct driver_info wwan_info = {
1665 	.description = "Mobile Broadband Network Device",
1666 	.flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
1667 			| FLAG_LINK_INTR | FLAG_WWAN,
1668 	.bind = cdc_ncm_bind,
1669 	.unbind = cdc_ncm_unbind,
1670 	.manage_power = usbnet_manage_power,
1671 	.status = cdc_ncm_status,
1672 	.rx_fixup = cdc_ncm_rx_fixup,
1673 	.tx_fixup = cdc_ncm_tx_fixup,
1674 };
1675 
1676 /* Same as wwan_info, but with FLAG_NOARP  */
1677 static const struct driver_info wwan_noarp_info = {
1678 	.description = "Mobile Broadband Network Device (NO ARP)",
1679 	.flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET
1680 			| FLAG_LINK_INTR | FLAG_WWAN | FLAG_NOARP,
1681 	.bind = cdc_ncm_bind,
1682 	.unbind = cdc_ncm_unbind,
1683 	.manage_power = usbnet_manage_power,
1684 	.status = cdc_ncm_status,
1685 	.rx_fixup = cdc_ncm_rx_fixup,
1686 	.tx_fixup = cdc_ncm_tx_fixup,
1687 };
1688 
1689 static const struct usb_device_id cdc_devs[] = {
1690 	/* Ericsson MBM devices like F5521gw */
1691 	{ .match_flags = USB_DEVICE_ID_MATCH_INT_INFO
1692 		| USB_DEVICE_ID_MATCH_VENDOR,
1693 	  .idVendor = 0x0bdb,
1694 	  .bInterfaceClass = USB_CLASS_COMM,
1695 	  .bInterfaceSubClass = USB_CDC_SUBCLASS_NCM,
1696 	  .bInterfaceProtocol = USB_CDC_PROTO_NONE,
1697 	  .driver_info = (unsigned long) &wwan_info,
1698 	},
1699 
1700 	/* Telit LE910 V2 */
1701 	{ USB_DEVICE_AND_INTERFACE_INFO(0x1bc7, 0x0036,
1702 		USB_CLASS_COMM,
1703 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
1704 	  .driver_info = (unsigned long)&wwan_noarp_info,
1705 	},
1706 
1707 	/* DW5812 LTE Verizon Mobile Broadband Card
1708 	 * Unlike DW5550 this device requires FLAG_NOARP
1709 	 */
1710 	{ USB_DEVICE_AND_INTERFACE_INFO(0x413c, 0x81bb,
1711 		USB_CLASS_COMM,
1712 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
1713 	  .driver_info = (unsigned long)&wwan_noarp_info,
1714 	},
1715 
1716 	/* DW5813 LTE AT&T Mobile Broadband Card
1717 	 * Unlike DW5550 this device requires FLAG_NOARP
1718 	 */
1719 	{ USB_DEVICE_AND_INTERFACE_INFO(0x413c, 0x81bc,
1720 		USB_CLASS_COMM,
1721 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
1722 	  .driver_info = (unsigned long)&wwan_noarp_info,
1723 	},
1724 
1725 	/* Dell branded MBM devices like DW5550 */
1726 	{ .match_flags = USB_DEVICE_ID_MATCH_INT_INFO
1727 		| USB_DEVICE_ID_MATCH_VENDOR,
1728 	  .idVendor = 0x413c,
1729 	  .bInterfaceClass = USB_CLASS_COMM,
1730 	  .bInterfaceSubClass = USB_CDC_SUBCLASS_NCM,
1731 	  .bInterfaceProtocol = USB_CDC_PROTO_NONE,
1732 	  .driver_info = (unsigned long) &wwan_info,
1733 	},
1734 
1735 	/* Toshiba branded MBM devices */
1736 	{ .match_flags = USB_DEVICE_ID_MATCH_INT_INFO
1737 		| USB_DEVICE_ID_MATCH_VENDOR,
1738 	  .idVendor = 0x0930,
1739 	  .bInterfaceClass = USB_CLASS_COMM,
1740 	  .bInterfaceSubClass = USB_CDC_SUBCLASS_NCM,
1741 	  .bInterfaceProtocol = USB_CDC_PROTO_NONE,
1742 	  .driver_info = (unsigned long) &wwan_info,
1743 	},
1744 
1745 	/* tag Huawei devices as wwan */
1746 	{ USB_VENDOR_AND_INTERFACE_INFO(0x12d1,
1747 					USB_CLASS_COMM,
1748 					USB_CDC_SUBCLASS_NCM,
1749 					USB_CDC_PROTO_NONE),
1750 	  .driver_info = (unsigned long)&wwan_info,
1751 	},
1752 
1753 	/* Infineon(now Intel) HSPA Modem platform */
1754 	{ USB_DEVICE_AND_INTERFACE_INFO(0x1519, 0x0443,
1755 		USB_CLASS_COMM,
1756 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
1757 	  .driver_info = (unsigned long)&wwan_noarp_info,
1758 	},
1759 
1760 	/* u-blox TOBY-L4 */
1761 	{ USB_DEVICE_AND_INTERFACE_INFO(0x1546, 0x1010,
1762 		USB_CLASS_COMM,
1763 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
1764 	  .driver_info = (unsigned long)&wwan_info,
1765 	},
1766 
1767 	/* Generic CDC-NCM devices */
1768 	{ USB_INTERFACE_INFO(USB_CLASS_COMM,
1769 		USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
1770 		.driver_info = (unsigned long)&cdc_ncm_info,
1771 	},
1772 	{
1773 	},
1774 };
1775 MODULE_DEVICE_TABLE(usb, cdc_devs);
1776 
1777 static struct usb_driver cdc_ncm_driver = {
1778 	.name = "cdc_ncm",
1779 	.id_table = cdc_devs,
1780 	.probe = usbnet_probe,
1781 	.disconnect = usbnet_disconnect,
1782 	.suspend = usbnet_suspend,
1783 	.resume = usbnet_resume,
1784 	.reset_resume =	usbnet_resume,
1785 	.supports_autosuspend = 1,
1786 	.disable_hub_initiated_lpm = 1,
1787 };
1788 
1789 module_usb_driver(cdc_ncm_driver);
1790 
1791 MODULE_AUTHOR("Hans Petter Selasky");
1792 MODULE_DESCRIPTION("USB CDC NCM host driver");
1793 MODULE_LICENSE("Dual BSD/GPL");
1794