drivers/net/usb/cdc_mbim.c - kernel/common - Git at Google

 /*
  * Copyright (c) 2012  Smith Micro Software, Inc.
  * Copyright (c) 2012  Bjørn Mork <[email protected]>
  *
  * This driver is based on and reuse most of cdc_ncm, which is
  * Copyright (C) ST-Ericsson 2010-2012
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * version 2 as published by the Free Software Foundation.
  */

 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/ethtool.h>
 #include <linux/if_vlan.h>
 #include <linux/ip.h>
 #include <linux/mii.h>
 #include <linux/usb.h>
 #include <linux/usb/cdc.h>
 #include <linux/usb/usbnet.h>
 #include <linux/usb/cdc-wdm.h>
 #include <linux/usb/cdc_ncm.h>
 #include <net/ipv6.h>
 #include <net/addrconf.h>

 /* alternative VLAN for IP session 0 if not untagged */
 #define MBIM_IPS0_VID	4094

 /* driver specific data - must match cdc_ncm usage */
 struct cdc_mbim_state {
 	struct cdc_ncm_ctx *ctx;
 	atomic_t pmcount;
 	struct usb_driver *subdriver;
 	unsigned long _unused;
 	unsigned long flags;
 };

 /* flags for the cdc_mbim_state.flags field */
 enum cdc_mbim_flags {
 	FLAG_IPS0_VLAN = 1 << 0,	/* IP session 0 is tagged  */
 };

 /* using a counter to merge subdriver requests with our own into a combined state */
 static int cdc_mbim_manage_power(struct usbnet *dev, int on)
 {
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	int rv = 0;

 	dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__, atomic_read(&info->pmcount), on);

 	if ((on && atomic_add_return(1, &info->pmcount) == 1) || (!on && atomic_dec_and_test(&info->pmcount))) {
 		/* need autopm_get/put here to ensure the usbcore sees the new value */
 		rv = usb_autopm_get_interface(dev->intf);
 		dev->intf->needs_remote_wakeup = on;
 		if (!rv)
 			usb_autopm_put_interface(dev->intf);
 	}
 	return 0;
 }

 static int cdc_mbim_wdm_manage_power(struct usb_interface *intf, int status)
 {
 	struct usbnet *dev = usb_get_intfdata(intf);

 	/* can be called while disconnecting */
 	if (!dev)
 		return 0;

 	return cdc_mbim_manage_power(dev, status);
 }

 static int cdc_mbim_rx_add_vid(struct net_device *netdev, __be16 proto, u16 vid)
 {
 	struct usbnet *dev = netdev_priv(netdev);
 	struct cdc_mbim_state *info = (void *)&dev->data;

 	/* creation of this VLAN is a request to tag IP session 0 */
 	if (vid == MBIM_IPS0_VID)
 		info->flags |= FLAG_IPS0_VLAN;
 	else
 		if (vid >= 512)	/* we don't map these to MBIM session */
 			return -EINVAL;
 	return 0;
 }

 static int cdc_mbim_rx_kill_vid(struct net_device *netdev, __be16 proto, u16 vid)
 {
 	struct usbnet *dev = netdev_priv(netdev);
 	struct cdc_mbim_state *info = (void *)&dev->data;

 	/* this is a request for an untagged IP session 0 */
 	if (vid == MBIM_IPS0_VID)
 		info->flags &= ~FLAG_IPS0_VLAN;
 	return 0;
 }

 static const struct net_device_ops cdc_mbim_netdev_ops = {
 	.ndo_open             = usbnet_open,
 	.ndo_stop             = usbnet_stop,
 	.ndo_start_xmit       = usbnet_start_xmit,
 	.ndo_tx_timeout       = usbnet_tx_timeout,
 	.ndo_get_stats64      = usbnet_get_stats64,
 	.ndo_change_mtu       = cdc_ncm_change_mtu,
 	.ndo_set_mac_address  = eth_mac_addr,
 	.ndo_validate_addr    = eth_validate_addr,
 	.ndo_vlan_rx_add_vid  = cdc_mbim_rx_add_vid,
 	.ndo_vlan_rx_kill_vid = cdc_mbim_rx_kill_vid,
 };

 /* Change the control interface altsetting and update the .driver_info
  * pointer if the matching entry after changing class codes points to
  * a different struct
  */
 static int cdc_mbim_set_ctrlalt(struct usbnet *dev, struct usb_interface *intf, u8 alt)
 {
 	struct usb_driver *driver = to_usb_driver(intf->dev.driver);
 	const struct usb_device_id *id;
 	struct driver_info *info;
 	int ret;

 	ret = usb_set_interface(dev->udev,
 				intf->cur_altsetting->desc.bInterfaceNumber,
 				alt);
 	if (ret)
 		return ret;

 	id = usb_match_id(intf, driver->id_table);
 	if (!id)
 		return -ENODEV;

 	info = (struct driver_info *)id->driver_info;
 	if (info != dev->driver_info) {
 		dev_dbg(&intf->dev, "driver_info updated to '%s'\n",
 			info->description);
 		dev->driver_info = info;
 	}
 	return 0;
 }

 static int cdc_mbim_bind(struct usbnet *dev, struct usb_interface *intf)
 {
 	struct cdc_ncm_ctx *ctx;
 	struct usb_driver *subdriver = ERR_PTR(-ENODEV);
 	int ret = -ENODEV;
 	u8 data_altsetting = 1;
 	struct cdc_mbim_state *info = (void *)&dev->data;

 	/* should we change control altsetting on a NCM/MBIM function? */
 	if (cdc_ncm_select_altsetting(intf) == CDC_NCM_COMM_ALTSETTING_MBIM) {
 		data_altsetting = CDC_NCM_DATA_ALTSETTING_MBIM;
 		ret = cdc_mbim_set_ctrlalt(dev, intf, CDC_NCM_COMM_ALTSETTING_MBIM);
 		if (ret)
 			goto err;
 		ret = -ENODEV;
 	}

 	/* we will hit this for NCM/MBIM functions if prefer_mbim is false */
 	if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
 		goto err;

 	ret = cdc_ncm_bind_common(dev, intf, data_altsetting, dev->driver_info->data);
 	if (ret)
 		goto err;

 	ctx = info->ctx;

 	/* The MBIM descriptor and the status endpoint are required */
 	if (ctx->mbim_desc && dev->status)
 		subdriver = usb_cdc_wdm_register(ctx->control,
 						 &dev->status->desc,
 						 le16_to_cpu(ctx->mbim_desc->wMaxControlMessage),
 						 cdc_mbim_wdm_manage_power);
 	if (IS_ERR(subdriver)) {
 		ret = PTR_ERR(subdriver);
 		cdc_ncm_unbind(dev, intf);
 		goto err;
 	}

 	/* can't let usbnet use the interrupt endpoint */
 	dev->status = NULL;
 	info->subdriver = subdriver;

 	/* MBIM cannot do ARP */
 	dev->net->flags |= IFF_NOARP;

 	/* no need to put the VLAN tci in the packet headers */
 	dev->net->features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_FILTER;

 	/* monitor VLAN additions and removals */
 	dev->net->netdev_ops = &cdc_mbim_netdev_ops;
 err:
 	return ret;
 }

 static void cdc_mbim_unbind(struct usbnet *dev, struct usb_interface *intf)
 {
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;

 	/* disconnect subdriver from control interface */
 	if (info->subdriver && info->subdriver->disconnect)
 		info->subdriver->disconnect(ctx->control);
 	info->subdriver = NULL;

 	/* let NCM unbind clean up both control and data interface */
 	cdc_ncm_unbind(dev, intf);
 }

 /* verify that the ethernet protocol is IPv4 or IPv6 */
 static bool is_ip_proto(__be16 proto)
 {
 	switch (proto) {
 	case htons(ETH_P_IP):
 	case htons(ETH_P_IPV6):
 		return true;
 	}
 	return false;
 }

 static struct sk_buff *cdc_mbim_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 {
 	struct sk_buff *skb_out;
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;
 	__le32 sign = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN);
 	u16 tci = 0;
 	bool is_ip;
 	u8 *c;

 	if (!ctx)
 		goto error;

 	if (skb) {
 		if (skb->len <= ETH_HLEN)
 			goto error;

 		/* Some applications using e.g. packet sockets will
 		 * bypass the VLAN acceleration and create tagged
 		 * ethernet frames directly.  We primarily look for
 		 * the accelerated out-of-band tag, but fall back if
 		 * required
 		 */
 		skb_reset_mac_header(skb);
 		if (vlan_get_tag(skb, &tci) < 0 && skb->len > VLAN_ETH_HLEN &&
 		    __vlan_get_tag(skb, &tci) == 0) {
 			is_ip = is_ip_proto(vlan_eth_hdr(skb)->h_vlan_encapsulated_proto);
 			skb_pull(skb, VLAN_ETH_HLEN);
 		} else {
 			is_ip = is_ip_proto(eth_hdr(skb)->h_proto);
 			skb_pull(skb, ETH_HLEN);
 		}

 		/* Is IP session <0> tagged too? */
 		if (info->flags & FLAG_IPS0_VLAN) {
 			/* drop all untagged packets */
 			if (!tci)
 				goto error;
 			/* map MBIM_IPS0_VID to IPS<0> */
 			if (tci == MBIM_IPS0_VID)
 				tci = 0;
 		}

 		/* mapping VLANs to MBIM sessions:
 		 *   no tag     => IPS session <0> if !FLAG_IPS0_VLAN
 		 *   1 - 255    => IPS session <vlanid>
 		 *   256 - 511  => DSS session <vlanid - 256>
 		 *   512 - 4093 => unsupported, drop
 		 *   4094       => IPS session <0> if FLAG_IPS0_VLAN
 		 */

 		switch (tci & 0x0f00) {
 		case 0x0000: /* VLAN ID 0 - 255 */
 			if (!is_ip)
 				goto error;
 			c = (u8 *)&sign;
 			c[3] = tci;
 			break;
 		case 0x0100: /* VLAN ID 256 - 511 */
 			if (is_ip)
 				goto error;
 			sign = cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN);
 			c = (u8 *)&sign;
 			c[3] = tci;
 			break;
 		default:
 			netif_err(dev, tx_err, dev->net,
 				  "unsupported tci=0x%04x\n", tci);
 			goto error;
 		}
 	}

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

 error:
 	if (skb)
 		dev_kfree_skb_any(skb);

 	return NULL;
 }

 /* Some devices are known to send Neigbor Solicitation messages and
  * require Neigbor Advertisement replies.  The IPv6 core will not
  * respond since IFF_NOARP is set, so we must handle them ourselves.
  */
 static void do_neigh_solicit(struct usbnet *dev, u8 *buf, u16 tci)
 {
 	struct ipv6hdr *iph = (void *)buf;
 	struct nd_msg *msg = (void *)(iph + 1);
 	struct net_device *netdev;
 	struct inet6_dev *in6_dev;
 	bool is_router;

 	/* we'll only respond to requests from unicast addresses to
 	 * our solicited node addresses.
 	 */
 	if (!ipv6_addr_is_solict_mult(&iph->daddr) ||
 	    !(ipv6_addr_type(&iph->saddr) & IPV6_ADDR_UNICAST))
 		return;

 	/* need to send the NA on the VLAN dev, if any */
 	rcu_read_lock();
 	if (tci) {
 		netdev = __vlan_find_dev_deep_rcu(dev->net, htons(ETH_P_8021Q),
 						  tci);
 		if (!netdev) {
 			rcu_read_unlock();
 			return;
 		}
 	} else {
 		netdev = dev->net;
 	}
 	dev_hold(netdev);
 	rcu_read_unlock();

 	in6_dev = in6_dev_get(netdev);
 	if (!in6_dev)
 		goto out;
 	is_router = !!in6_dev->cnf.forwarding;
 	in6_dev_put(in6_dev);

 	/* ipv6_stub != NULL if in6_dev_get returned an inet6_dev */
 	ipv6_stub->ndisc_send_na(netdev, &iph->saddr, &msg->target,
 				 is_router /* router */,
 				 true /* solicited */,
 				 false /* override */,
 				 true /* inc_opt */);
 out:
 	dev_put(netdev);
 }

 static bool is_neigh_solicit(u8 *buf, size_t len)
 {
 	struct ipv6hdr *iph = (void *)buf;
 	struct nd_msg *msg = (void *)(iph + 1);

 	return (len >= sizeof(struct ipv6hdr) + sizeof(struct nd_msg) &&
 		iph->nexthdr == IPPROTO_ICMPV6 &&
 		msg->icmph.icmp6_code == 0 &&
 		msg->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION);
 }


 static struct sk_buff *cdc_mbim_process_dgram(struct usbnet *dev, u8 *buf, size_t len, u16 tci)
 {
 	__be16 proto = htons(ETH_P_802_3);
 	struct sk_buff *skb = NULL;

 	if (tci < 256 || tci == MBIM_IPS0_VID) { /* IPS session? */
 		if (len < sizeof(struct iphdr))
 			goto err;

 		switch (*buf & 0xf0) {
 		case 0x40:
 			proto = htons(ETH_P_IP);
 			break;
 		case 0x60:
 			if (is_neigh_solicit(buf, len))
 				do_neigh_solicit(dev, buf, tci);
 			proto = htons(ETH_P_IPV6);
 			break;
 		default:
 			goto err;
 		}
 	}

 	skb = netdev_alloc_skb_ip_align(dev->net,  len + ETH_HLEN);
 	if (!skb)
 		goto err;

 	/* add an ethernet header */
 	skb_put(skb, ETH_HLEN);
 	skb_reset_mac_header(skb);
 	eth_hdr(skb)->h_proto = proto;
 	eth_zero_addr(eth_hdr(skb)->h_source);
 	memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN);

 	/* add datagram */
 	skb_put_data(skb, buf, len);

 	/* map MBIM session to VLAN */
 	if (tci)
 		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), tci);
 err:
 	return skb;
 }

 static int cdc_mbim_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
 {
 	struct sk_buff *skb;
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;
 	int len;
 	int nframes;
 	int x;
 	int offset;
 	struct usb_cdc_ncm_ndp16 *ndp16;
 	struct usb_cdc_ncm_dpe16 *dpe16;
 	int ndpoffset;
 	int loopcount = 50; /* arbitrary max preventing infinite loop */
 	u32 payload = 0;
 	u8 *c;
 	u16 tci;

 	ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
 	if (ndpoffset < 0)
 		goto error;

 next_ndp:
 	nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
 	if (nframes < 0)
 		goto error;

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

 	switch (ndp16->dwSignature & cpu_to_le32(0x00ffffff)) {
 	case cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN):
 		c = (u8 *)&ndp16->dwSignature;
 		tci = c[3];
 		/* tag IPS<0> packets too if MBIM_IPS0_VID exists */
 		if (!tci && info->flags & FLAG_IPS0_VLAN)
 			tci = MBIM_IPS0_VID;
 		break;
 	case cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN):
 		c = (u8 *)&ndp16->dwSignature;
 		tci = c[3] + 256;
 		break;
 	default:
 		netif_dbg(dev, rx_err, dev->net,
 			  "unsupported NDP signature <0x%08x>\n",
 			  le32_to_cpu(ndp16->dwSignature));
 		goto err_ndp;

 	}

 	dpe16 = ndp16->dpe16;
 	for (x = 0; x < nframes; x++, dpe16++) {
 		offset = le16_to_cpu(dpe16->wDatagramIndex);
 		len = le16_to_cpu(dpe16->wDatagramLength);

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

 		/* sanity checking */
 		if (((offset + len) > skb_in->len) || (len > ctx->rx_max)) {
 			netif_dbg(dev, rx_err, dev->net,
 				  "invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
 				  x, offset, len, skb_in);
 			if (!x)
 				goto err_ndp;
 			break;
 		} else {
 			skb = cdc_mbim_process_dgram(dev, skb_in->data + offset, len, tci);
 			if (!skb)
 				goto error;
 			usbnet_skb_return(dev, skb);
 			payload += len;	/* count payload bytes in this NTB */
 		}
 	}
 err_ndp:
 	/* are there more NDPs to process? */
 	ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
 	if (ndpoffset && loopcount--)
 		goto next_ndp;

 	/* update stats */
 	ctx->rx_overhead += skb_in->len - payload;
 	ctx->rx_ntbs++;

 	return 1;
 error:
 	return 0;
 }

 static int cdc_mbim_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	int ret = -ENODEV;
 	struct usbnet *dev = usb_get_intfdata(intf);
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;

 	if (!ctx)
 		goto error;

 	/*
 	 * Both usbnet_suspend() and subdriver->suspend() MUST return 0
 	 * in system sleep context, otherwise, the resume callback has
 	 * to recover device from previous suspend failure.
 	 */
 	ret = usbnet_suspend(intf, message);
 	if (ret < 0)
 		goto error;

 	if (intf == ctx->control && info->subdriver && info->subdriver->suspend)
 		ret = info->subdriver->suspend(intf, message);
 	if (ret < 0)
 		usbnet_resume(intf);

 error:
 	return ret;
 }

 static int cdc_mbim_resume(struct usb_interface *intf)
 {
 	int  ret = 0;
 	struct usbnet *dev = usb_get_intfdata(intf);
 	struct cdc_mbim_state *info = (void *)&dev->data;
 	struct cdc_ncm_ctx *ctx = info->ctx;
 	bool callsub = (intf == ctx->control && info->subdriver && info->subdriver->resume);

 	if (callsub)
 		ret = info->subdriver->resume(intf);
 	if (ret < 0)
 		goto err;
 	ret = usbnet_resume(intf);
 	if (ret < 0 && callsub)
 		info->subdriver->suspend(intf, PMSG_SUSPEND);
 err:
 	return ret;
 }

 static const struct driver_info cdc_mbim_info = {
 	.description = "CDC MBIM",
 	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
 	.bind = cdc_mbim_bind,
 	.unbind = cdc_mbim_unbind,
 	.manage_power = cdc_mbim_manage_power,
 	.rx_fixup = cdc_mbim_rx_fixup,
 	.tx_fixup = cdc_mbim_tx_fixup,
 };

 /* MBIM and NCM devices should not need a ZLP after NTBs with
  * dwNtbOutMaxSize length. Nevertheless, a number of devices from
  * different vendor IDs will fail unless we send ZLPs, forcing us
  * to make this the default.
  *
  * This default may cause a performance penalty for spec conforming
  * devices wanting to take advantage of optimizations possible without
  * ZLPs.  A whitelist is added in an attempt to avoid this for devices
  * known to conform to the MBIM specification.
  *
  * All known devices supporting NCM compatibility mode are also
  * conforming to the NCM and MBIM specifications. For this reason, the
  * NCM subclass entry is also in the ZLP whitelist.
  */
 static const struct driver_info cdc_mbim_info_zlp = {
 	.description = "CDC MBIM",
 	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN | FLAG_SEND_ZLP,
 	.bind = cdc_mbim_bind,
 	.unbind = cdc_mbim_unbind,
 	.manage_power = cdc_mbim_manage_power,
 	.rx_fixup = cdc_mbim_rx_fixup,
 	.tx_fixup = cdc_mbim_tx_fixup,
 };

 /* The spefication explicitly allows NDPs to be placed anywhere in the
  * frame, but some devices fail unless the NDP is placed after the IP
  * packets.  Using the CDC_NCM_FLAG_NDP_TO_END flags to force this
  * behaviour.
  *
  * Note: The current implementation of this feature restricts each NTB
  * to a single NDP, implying that multiplexed sessions cannot share an
  * NTB. This might affect performace for multiplexed sessions.
  */
 static const struct driver_info cdc_mbim_info_ndp_to_end = {
 	.description = "CDC MBIM",
 	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
 	.bind = cdc_mbim_bind,
 	.unbind = cdc_mbim_unbind,
 	.manage_power = cdc_mbim_manage_power,
 	.rx_fixup = cdc_mbim_rx_fixup,
 	.tx_fixup = cdc_mbim_tx_fixup,
 	.data = CDC_NCM_FLAG_NDP_TO_END,
 };

 /* Some modems (e.g. Telit LE922A6) do not work properly with altsetting
  * toggle done in cdc_ncm_bind_common. CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE
  * flag is used to avoid this procedure.
  */
 static const struct driver_info cdc_mbim_info_avoid_altsetting_toggle = {
 	.description = "CDC MBIM",
 	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN | FLAG_SEND_ZLP,
 	.bind = cdc_mbim_bind,
 	.unbind = cdc_mbim_unbind,
 	.manage_power = cdc_mbim_manage_power,
 	.rx_fixup = cdc_mbim_rx_fixup,
 	.tx_fixup = cdc_mbim_tx_fixup,
 	.data = CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE,
 };

 static const struct usb_device_id mbim_devs[] = {
 	/* This duplicate NCM entry is intentional. MBIM devices can
 	 * be disguised as NCM by default, and this is necessary to
 	 * allow us to bind the correct driver_info to such devices.
 	 *
 	 * bind() will sort out this for us, selecting the correct
 	 * entry and reject the other
 	 */
 	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info,
 	},
 	/* ZLP conformance whitelist: All Ericsson MBIM devices */
 	{ USB_VENDOR_AND_INTERFACE_INFO(0x0bdb, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info,
 	},

 	/* Some Huawei devices, ME906s-158 (12d1:15c1) and E3372
 	 * (12d1:157d), are known to fail unless the NDP is placed
 	 * after the IP packets.  Applying the quirk to all Huawei
 	 * devices is broader than necessary, but harmless.
 	 */
 	{ USB_VENDOR_AND_INTERFACE_INFO(0x12d1, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info_ndp_to_end,
 	},

 	/* The HP lt4132 (03f0:a31d) is a rebranded Huawei ME906s-158,
 	 * therefore it too requires the above "NDP to end" quirk.
 	 */
 	{ USB_DEVICE_AND_INTERFACE_INFO(0x03f0, 0xa31d, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info_ndp_to_end,
 	},

 	/* Telit LE922A6 in MBIM composition */
 	{ USB_DEVICE_AND_INTERFACE_INFO(0x1bc7, 0x1041, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info_avoid_altsetting_toggle,
 	},

 	/* default entry */
 	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
 	  .driver_info = (unsigned long)&cdc_mbim_info_zlp,
 	},
 	{
 	},
 };
 MODULE_DEVICE_TABLE(usb, mbim_devs);

 static struct usb_driver cdc_mbim_driver = {
 	.name = "cdc_mbim",
 	.id_table = mbim_devs,
 	.probe = usbnet_probe,
 	.disconnect = usbnet_disconnect,
 	.suspend = cdc_mbim_suspend,
 	.resume = cdc_mbim_resume,
 	.reset_resume =	cdc_mbim_resume,
 	.supports_autosuspend = 1,
 	.disable_hub_initiated_lpm = 1,
 };
 module_usb_driver(cdc_mbim_driver);

 MODULE_AUTHOR("Greg Suarez <[email protected]>");
 MODULE_AUTHOR("Bjørn Mork <[email protected]>");
 MODULE_DESCRIPTION("USB CDC MBIM host driver");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (c) 2012 Smith Micro Software, Inc.
	* Copyright (c) 2012 Bjørn Mork <[email protected]>
	*
	* This driver is based on and reuse most of cdc_ncm, which is
	* Copyright (C) ST-Ericsson 2010-2012
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* version 2 as published by the Free Software Foundation.
	*/

	#include <linux/module.h>
	#include <linux/netdevice.h>
	#include <linux/ethtool.h>
	#include <linux/if_vlan.h>
	#include <linux/ip.h>
	#include <linux/mii.h>
	#include <linux/usb.h>
	#include <linux/usb/cdc.h>
	#include <linux/usb/usbnet.h>
	#include <linux/usb/cdc-wdm.h>
	#include <linux/usb/cdc_ncm.h>
	#include <net/ipv6.h>
	#include <net/addrconf.h>

	/* alternative VLAN for IP session 0 if not untagged */
	#define MBIM_IPS0_VID 4094

	/* driver specific data - must match cdc_ncm usage */
	struct cdc_mbim_state {
	struct cdc_ncm_ctx *ctx;
	atomic_t pmcount;
	struct usb_driver *subdriver;
	unsigned long _unused;
	unsigned long flags;
	};

	/* flags for the cdc_mbim_state.flags field */
	enum cdc_mbim_flags {
	FLAG_IPS0_VLAN = 1 << 0, /* IP session 0 is tagged */
	};

	/* using a counter to merge subdriver requests with our own into a combined state */
	static int cdc_mbim_manage_power(struct usbnet *dev, int on)
	{
	struct cdc_mbim_state info = (void )&dev->data;
	int rv = 0;

	dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__, atomic_read(&info->pmcount), on);

	if ((on && atomic_add_return(1, &info->pmcount) == 1) \|\| (!on && atomic_dec_and_test(&info->pmcount))) {
	/* need autopm_get/put here to ensure the usbcore sees the new value */
	rv = usb_autopm_get_interface(dev->intf);
	dev->intf->needs_remote_wakeup = on;
	if (!rv)
	usb_autopm_put_interface(dev->intf);
	}
	return 0;
	}

	static int cdc_mbim_wdm_manage_power(struct usb_interface *intf, int status)
	{
	struct usbnet *dev = usb_get_intfdata(intf);

	/* can be called while disconnecting */
	if (!dev)
	return 0;

	return cdc_mbim_manage_power(dev, status);
	}

	static int cdc_mbim_rx_add_vid(struct net_device *netdev, __be16 proto, u16 vid)
	{
	struct usbnet *dev = netdev_priv(netdev);
	struct cdc_mbim_state info = (void )&dev->data;

	/* creation of this VLAN is a request to tag IP session 0 */
	if (vid == MBIM_IPS0_VID)
	info->flags \|= FLAG_IPS0_VLAN;
	else
	if (vid >= 512) /* we don't map these to MBIM session */
	return -EINVAL;
	return 0;
	}

	static int cdc_mbim_rx_kill_vid(struct net_device *netdev, __be16 proto, u16 vid)
	{
	struct usbnet *dev = netdev_priv(netdev);
	struct cdc_mbim_state info = (void )&dev->data;

	/* this is a request for an untagged IP session 0 */
	if (vid == MBIM_IPS0_VID)
	info->flags &= ~FLAG_IPS0_VLAN;
	return 0;
	}

	static const struct net_device_ops cdc_mbim_netdev_ops = {
	.ndo_open = usbnet_open,
	.ndo_stop = usbnet_stop,
	.ndo_start_xmit = usbnet_start_xmit,
	.ndo_tx_timeout = usbnet_tx_timeout,
	.ndo_get_stats64 = usbnet_get_stats64,
	.ndo_change_mtu = cdc_ncm_change_mtu,
	.ndo_set_mac_address = eth_mac_addr,
	.ndo_validate_addr = eth_validate_addr,
	.ndo_vlan_rx_add_vid = cdc_mbim_rx_add_vid,
	.ndo_vlan_rx_kill_vid = cdc_mbim_rx_kill_vid,
	};

	/* Change the control interface altsetting and update the .driver_info
	* pointer if the matching entry after changing class codes points to
	* a different struct
	*/
	static int cdc_mbim_set_ctrlalt(struct usbnet dev, struct usb_interface intf, u8 alt)
	{
	struct usb_driver *driver = to_usb_driver(intf->dev.driver);
	const struct usb_device_id *id;
	struct driver_info *info;
	int ret;

	ret = usb_set_interface(dev->udev,
	intf->cur_altsetting->desc.bInterfaceNumber,
	alt);
	if (ret)
	return ret;

	id = usb_match_id(intf, driver->id_table);
	if (!id)
	return -ENODEV;

	info = (struct driver_info *)id->driver_info;
	if (info != dev->driver_info) {
	dev_dbg(&intf->dev, "driver_info updated to '%s'\n",
	info->description);
	dev->driver_info = info;
	}
	return 0;
	}

	static int cdc_mbim_bind(struct usbnet dev, struct usb_interface intf)
	{
	struct cdc_ncm_ctx *ctx;
	struct usb_driver *subdriver = ERR_PTR(-ENODEV);
	int ret = -ENODEV;
	u8 data_altsetting = 1;
	struct cdc_mbim_state info = (void )&dev->data;

	/* should we change control altsetting on a NCM/MBIM function? */
	if (cdc_ncm_select_altsetting(intf) == CDC_NCM_COMM_ALTSETTING_MBIM) {
	data_altsetting = CDC_NCM_DATA_ALTSETTING_MBIM;
	ret = cdc_mbim_set_ctrlalt(dev, intf, CDC_NCM_COMM_ALTSETTING_MBIM);
	if (ret)
	goto err;
	ret = -ENODEV;
	}

	/* we will hit this for NCM/MBIM functions if prefer_mbim is false */
	if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
	goto err;

	ret = cdc_ncm_bind_common(dev, intf, data_altsetting, dev->driver_info->data);
	if (ret)
	goto err;

	ctx = info->ctx;

	/* The MBIM descriptor and the status endpoint are required */
	if (ctx->mbim_desc && dev->status)
	subdriver = usb_cdc_wdm_register(ctx->control,
	&dev->status->desc,
	le16_to_cpu(ctx->mbim_desc->wMaxControlMessage),
	cdc_mbim_wdm_manage_power);
	if (IS_ERR(subdriver)) {
	ret = PTR_ERR(subdriver);
	cdc_ncm_unbind(dev, intf);
	goto err;
	}

	/* can't let usbnet use the interrupt endpoint */
	dev->status = NULL;
	info->subdriver = subdriver;

	/* MBIM cannot do ARP */
	dev->net->flags \|= IFF_NOARP;

	/* no need to put the VLAN tci in the packet headers */
	dev->net->features \|= NETIF_F_HW_VLAN_CTAG_TX \| NETIF_F_HW_VLAN_CTAG_FILTER;

	/* monitor VLAN additions and removals */
	dev->net->netdev_ops = &cdc_mbim_netdev_ops;
	err:
	return ret;
	}

	static void cdc_mbim_unbind(struct usbnet dev, struct usb_interface intf)
	{
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;

	/* disconnect subdriver from control interface */
	if (info->subdriver && info->subdriver->disconnect)
	info->subdriver->disconnect(ctx->control);
	info->subdriver = NULL;

	/* let NCM unbind clean up both control and data interface */
	cdc_ncm_unbind(dev, intf);
	}

	/* verify that the ethernet protocol is IPv4 or IPv6 */
	static bool is_ip_proto(__be16 proto)
	{
	switch (proto) {
	case htons(ETH_P_IP):
	case htons(ETH_P_IPV6):
	return true;
	}
	return false;
	}

	static struct sk_buff cdc_mbim_tx_fixup(struct usbnet dev, struct sk_buff *skb, gfp_t flags)
	{
	struct sk_buff *skb_out;
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;
	__le32 sign = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN);
	u16 tci = 0;
	bool is_ip;
	u8 *c;

	if (!ctx)
	goto error;

	if (skb) {
	if (skb->len <= ETH_HLEN)
	goto error;

	/* Some applications using e.g. packet sockets will
	* bypass the VLAN acceleration and create tagged
	* ethernet frames directly. We primarily look for
	* the accelerated out-of-band tag, but fall back if
	* required
	*/
	skb_reset_mac_header(skb);
	if (vlan_get_tag(skb, &tci) < 0 && skb->len > VLAN_ETH_HLEN &&
	__vlan_get_tag(skb, &tci) == 0) {
	is_ip = is_ip_proto(vlan_eth_hdr(skb)->h_vlan_encapsulated_proto);
	skb_pull(skb, VLAN_ETH_HLEN);
	} else {
	is_ip = is_ip_proto(eth_hdr(skb)->h_proto);
	skb_pull(skb, ETH_HLEN);
	}

	/* Is IP session <0> tagged too? */
	if (info->flags & FLAG_IPS0_VLAN) {
	/* drop all untagged packets */
	if (!tci)
	goto error;
	/* map MBIM_IPS0_VID to IPS<0> */
	if (tci == MBIM_IPS0_VID)
	tci = 0;
	}

	/* mapping VLANs to MBIM sessions:
	* no tag => IPS session <0> if !FLAG_IPS0_VLAN
	* 1 - 255 => IPS session <vlanid>
	* 256 - 511 => DSS session <vlanid - 256>
	* 512 - 4093 => unsupported, drop
	* 4094 => IPS session <0> if FLAG_IPS0_VLAN
	*/

	switch (tci & 0x0f00) {
	case 0x0000: /* VLAN ID 0 - 255 */
	if (!is_ip)
	goto error;
	c = (u8 *)&sign;
	c[3] = tci;
	break;
	case 0x0100: /* VLAN ID 256 - 511 */
	if (is_ip)
	goto error;
	sign = cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN);
	c = (u8 *)&sign;
	c[3] = tci;
	break;
	default:
	netif_err(dev, tx_err, dev->net,
	"unsupported tci=0x%04x\n", tci);
	goto error;
	}
	}

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

	error:
	if (skb)
	dev_kfree_skb_any(skb);

	return NULL;
	}

	/* Some devices are known to send Neigbor Solicitation messages and
	* require Neigbor Advertisement replies. The IPv6 core will not
	* respond since IFF_NOARP is set, so we must handle them ourselves.
	*/
	static void do_neigh_solicit(struct usbnet dev, u8 buf, u16 tci)
	{
	struct ipv6hdr iph = (void )buf;
	struct nd_msg msg = (void )(iph + 1);
	struct net_device *netdev;
	struct inet6_dev *in6_dev;
	bool is_router;

	/* we'll only respond to requests from unicast addresses to
	* our solicited node addresses.
	*/
	if (!ipv6_addr_is_solict_mult(&iph->daddr) \|\|
	!(ipv6_addr_type(&iph->saddr) & IPV6_ADDR_UNICAST))
	return;

	/* need to send the NA on the VLAN dev, if any */
	rcu_read_lock();
	if (tci) {
	netdev = __vlan_find_dev_deep_rcu(dev->net, htons(ETH_P_8021Q),
	tci);
	if (!netdev) {
	rcu_read_unlock();
	return;
	}
	} else {
	netdev = dev->net;
	}
	dev_hold(netdev);
	rcu_read_unlock();

	in6_dev = in6_dev_get(netdev);
	if (!in6_dev)
	goto out;
	is_router = !!in6_dev->cnf.forwarding;
	in6_dev_put(in6_dev);

	/* ipv6_stub != NULL if in6_dev_get returned an inet6_dev */
	ipv6_stub->ndisc_send_na(netdev, &iph->saddr, &msg->target,
	is_router /* router */,
	true /* solicited */,
	false /* override */,
	true /* inc_opt */);
	out:
	dev_put(netdev);
	}

	static bool is_neigh_solicit(u8 *buf, size_t len)
	{
	struct ipv6hdr iph = (void )buf;
	struct nd_msg msg = (void )(iph + 1);

	return (len >= sizeof(struct ipv6hdr) + sizeof(struct nd_msg) &&
	iph->nexthdr == IPPROTO_ICMPV6 &&
	msg->icmph.icmp6_code == 0 &&
	msg->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION);
	}


	static struct sk_buff cdc_mbim_process_dgram(struct usbnet dev, u8 *buf, size_t len, u16 tci)
	{
	__be16 proto = htons(ETH_P_802_3);
	struct sk_buff *skb = NULL;

	if (tci < 256 \|\| tci == MBIM_IPS0_VID) { /* IPS session? */
	if (len < sizeof(struct iphdr))
	goto err;

	switch (*buf & 0xf0) {
	case 0x40:
	proto = htons(ETH_P_IP);
	break;
	case 0x60:
	if (is_neigh_solicit(buf, len))
	do_neigh_solicit(dev, buf, tci);
	proto = htons(ETH_P_IPV6);
	break;
	default:
	goto err;
	}
	}

	skb = netdev_alloc_skb_ip_align(dev->net, len + ETH_HLEN);
	if (!skb)
	goto err;

	/* add an ethernet header */
	skb_put(skb, ETH_HLEN);
	skb_reset_mac_header(skb);
	eth_hdr(skb)->h_proto = proto;
	eth_zero_addr(eth_hdr(skb)->h_source);
	memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN);

	/* add datagram */
	skb_put_data(skb, buf, len);

	/* map MBIM session to VLAN */
	if (tci)
	__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), tci);
	err:
	return skb;
	}

	static int cdc_mbim_rx_fixup(struct usbnet dev, struct sk_buff skb_in)
	{
	struct sk_buff *skb;
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;
	int len;
	int nframes;
	int x;
	int offset;
	struct usb_cdc_ncm_ndp16 *ndp16;
	struct usb_cdc_ncm_dpe16 *dpe16;
	int ndpoffset;
	int loopcount = 50; /* arbitrary max preventing infinite loop */
	u32 payload = 0;
	u8 *c;
	u16 tci;

	ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
	if (ndpoffset < 0)
	goto error;

	next_ndp:
	nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
	if (nframes < 0)
	goto error;

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

	switch (ndp16->dwSignature & cpu_to_le32(0x00ffffff)) {
	case cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN):
	c = (u8 *)&ndp16->dwSignature;
	tci = c[3];
	/* tag IPS<0> packets too if MBIM_IPS0_VID exists */
	if (!tci && info->flags & FLAG_IPS0_VLAN)
	tci = MBIM_IPS0_VID;
	break;
	case cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN):
	c = (u8 *)&ndp16->dwSignature;
	tci = c[3] + 256;
	break;
	default:
	netif_dbg(dev, rx_err, dev->net,
	"unsupported NDP signature <0x%08x>\n",
	le32_to_cpu(ndp16->dwSignature));
	goto err_ndp;

	}

	dpe16 = ndp16->dpe16;
	for (x = 0; x < nframes; x++, dpe16++) {
	offset = le16_to_cpu(dpe16->wDatagramIndex);
	len = le16_to_cpu(dpe16->wDatagramLength);

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

	/* sanity checking */
	if (((offset + len) > skb_in->len) \|\| (len > ctx->rx_max)) {
	netif_dbg(dev, rx_err, dev->net,
	"invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
	x, offset, len, skb_in);
	if (!x)
	goto err_ndp;
	break;
	} else {
	skb = cdc_mbim_process_dgram(dev, skb_in->data + offset, len, tci);
	if (!skb)
	goto error;
	usbnet_skb_return(dev, skb);
	payload += len; /* count payload bytes in this NTB */
	}
	}
	err_ndp:
	/* are there more NDPs to process? */
	ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
	if (ndpoffset && loopcount--)
	goto next_ndp;

	/* update stats */
	ctx->rx_overhead += skb_in->len - payload;
	ctx->rx_ntbs++;

	return 1;
	error:
	return 0;
	}

	static int cdc_mbim_suspend(struct usb_interface *intf, pm_message_t message)
	{
	int ret = -ENODEV;
	struct usbnet *dev = usb_get_intfdata(intf);
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;

	if (!ctx)
	goto error;

	/*
	* Both usbnet_suspend() and subdriver->suspend() MUST return 0
	* in system sleep context, otherwise, the resume callback has
	* to recover device from previous suspend failure.
	*/
	ret = usbnet_suspend(intf, message);
	if (ret < 0)
	goto error;

	if (intf == ctx->control && info->subdriver && info->subdriver->suspend)
	ret = info->subdriver->suspend(intf, message);
	if (ret < 0)
	usbnet_resume(intf);

	error:
	return ret;
	}

	static int cdc_mbim_resume(struct usb_interface *intf)
	{
	int ret = 0;
	struct usbnet *dev = usb_get_intfdata(intf);
	struct cdc_mbim_state info = (void )&dev->data;
	struct cdc_ncm_ctx *ctx = info->ctx;
	bool callsub = (intf == ctx->control && info->subdriver && info->subdriver->resume);

	if (callsub)
	ret = info->subdriver->resume(intf);
	if (ret < 0)
	goto err;
	ret = usbnet_resume(intf);
	if (ret < 0 && callsub)
	info->subdriver->suspend(intf, PMSG_SUSPEND);
	err:
	return ret;
	}

	static const struct driver_info cdc_mbim_info = {
	.description = "CDC MBIM",
	.flags = FLAG_NO_SETINT \| FLAG_MULTI_PACKET \| FLAG_WWAN,
	.bind = cdc_mbim_bind,
	.unbind = cdc_mbim_unbind,
	.manage_power = cdc_mbim_manage_power,
	.rx_fixup = cdc_mbim_rx_fixup,
	.tx_fixup = cdc_mbim_tx_fixup,
	};

	/* MBIM and NCM devices should not need a ZLP after NTBs with
	* dwNtbOutMaxSize length. Nevertheless, a number of devices from
	* different vendor IDs will fail unless we send ZLPs, forcing us
	* to make this the default.
	*
	* This default may cause a performance penalty for spec conforming
	* devices wanting to take advantage of optimizations possible without
	* ZLPs. A whitelist is added in an attempt to avoid this for devices
	* known to conform to the MBIM specification.
	*
	* All known devices supporting NCM compatibility mode are also
	* conforming to the NCM and MBIM specifications. For this reason, the
	* NCM subclass entry is also in the ZLP whitelist.
	*/
	static const struct driver_info cdc_mbim_info_zlp = {
	.description = "CDC MBIM",
	.flags = FLAG_NO_SETINT \| FLAG_MULTI_PACKET \| FLAG_WWAN \| FLAG_SEND_ZLP,
	.bind = cdc_mbim_bind,
	.unbind = cdc_mbim_unbind,
	.manage_power = cdc_mbim_manage_power,
	.rx_fixup = cdc_mbim_rx_fixup,
	.tx_fixup = cdc_mbim_tx_fixup,
	};

	/* The spefication explicitly allows NDPs to be placed anywhere in the
	* frame, but some devices fail unless the NDP is placed after the IP
	* packets. Using the CDC_NCM_FLAG_NDP_TO_END flags to force this
	* behaviour.
	*
	* Note: The current implementation of this feature restricts each NTB
	* to a single NDP, implying that multiplexed sessions cannot share an
	* NTB. This might affect performace for multiplexed sessions.
	*/
	static const struct driver_info cdc_mbim_info_ndp_to_end = {
	.description = "CDC MBIM",
	.flags = FLAG_NO_SETINT \| FLAG_MULTI_PACKET \| FLAG_WWAN,
	.bind = cdc_mbim_bind,
	.unbind = cdc_mbim_unbind,
	.manage_power = cdc_mbim_manage_power,
	.rx_fixup = cdc_mbim_rx_fixup,
	.tx_fixup = cdc_mbim_tx_fixup,
	.data = CDC_NCM_FLAG_NDP_TO_END,
	};

	/* Some modems (e.g. Telit LE922A6) do not work properly with altsetting
	* toggle done in cdc_ncm_bind_common. CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE
	* flag is used to avoid this procedure.
	*/
	static const struct driver_info cdc_mbim_info_avoid_altsetting_toggle = {
	.description = "CDC MBIM",
	.flags = FLAG_NO_SETINT \| FLAG_MULTI_PACKET \| FLAG_WWAN \| FLAG_SEND_ZLP,
	.bind = cdc_mbim_bind,
	.unbind = cdc_mbim_unbind,
	.manage_power = cdc_mbim_manage_power,
	.rx_fixup = cdc_mbim_rx_fixup,
	.tx_fixup = cdc_mbim_tx_fixup,
	.data = CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE,
	};

	static const struct usb_device_id mbim_devs[] = {
	/* This duplicate NCM entry is intentional. MBIM devices can
	* be disguised as NCM by default, and this is necessary to
	* allow us to bind the correct driver_info to such devices.
	*
	* bind() will sort out this for us, selecting the correct
	* entry and reject the other
	*/
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long)&cdc_mbim_info,
	},
	/* ZLP conformance whitelist: All Ericsson MBIM devices */
	{ USB_VENDOR_AND_INTERFACE_INFO(0x0bdb, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long)&cdc_mbim_info,
	},

	/* Some Huawei devices, ME906s-158 (12d1:15c1) and E3372
	* (12d1:157d), are known to fail unless the NDP is placed
	* after the IP packets. Applying the quirk to all Huawei
	* devices is broader than necessary, but harmless.
	*/
	{ USB_VENDOR_AND_INTERFACE_INFO(0x12d1, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long)&cdc_mbim_info_ndp_to_end,
	},

	/* The HP lt4132 (03f0:a31d) is a rebranded Huawei ME906s-158,
	* therefore it too requires the above "NDP to end" quirk.
	*/
	{ USB_DEVICE_AND_INTERFACE_INFO(0x03f0, 0xa31d, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long)&cdc_mbim_info_ndp_to_end,
	},

	/* Telit LE922A6 in MBIM composition */
	{ USB_DEVICE_AND_INTERFACE_INFO(0x1bc7, 0x1041, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long)&cdc_mbim_info_avoid_altsetting_toggle,
	},

	/* default entry */
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
	.driver_info = (unsigned long)&cdc_mbim_info_zlp,
	},
	{
	},
	};
	MODULE_DEVICE_TABLE(usb, mbim_devs);

	static struct usb_driver cdc_mbim_driver = {
	.name = "cdc_mbim",
	.id_table = mbim_devs,
	.probe = usbnet_probe,
	.disconnect = usbnet_disconnect,
	.suspend = cdc_mbim_suspend,
	.resume = cdc_mbim_resume,
	.reset_resume = cdc_mbim_resume,
	.supports_autosuspend = 1,
	.disable_hub_initiated_lpm = 1,
	};
	module_usb_driver(cdc_mbim_driver);

	MODULE_AUTHOR("Greg Suarez <[email protected]>");
	MODULE_AUTHOR("Bjørn Mork <[email protected]>");
	MODULE_DESCRIPTION("USB CDC MBIM host driver");
	MODULE_LICENSE("GPL");