![Bjørn Mork](/assets/img/avatar_default.png)
Reverting328d7b8
and instead adding an exception for the Sierra Wireless MC7710. commit328d7b8
(net: cdc_mbim: send ZLP after max sized NTBs) added a workaround for an issue observed on one specific device. Concerns were raised that this workaround adds a performance penalty to all devices based on questionable, if not buggy, behaviour of a single device: "If you add ZLP for NTBs of dwNtbOutMaxSize, you are heavily affecting CPU load, increasing interrupt load by factor of 2 in high load traffic scenario and possibly decreasing throughput for all other devices which behaves correctly." "The idea of NCM was to avoid extra ZLPs. If your transfer is exactly dwNtbOutMaxSize, it's known, you can submit such request on the receiver side and you do not need any EOT indicatation, so the frametime can be used for useful data." Adding a device specific exception to prevent the workaround from affecting well behaved devices. The assumption here is that needing a ZLP is truly an *exception*. We do not yet have enough data to verify this. The generic workaround in commit328d7b8
should be considered acceptable despite the performance penalty if the exception list becomes a maintainance hassle. Cc: Alexey ORISHKO <alexey.orishko@stericsson.com> Cc: Yauheni Kaliuta <y.kaliuta@gmail.com> Signed-off-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: David S. Miller <davem@davemloft.net>
432 lines
11 KiB
C
432 lines
11 KiB
C
/*
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* Copyright (c) 2012 Smith Micro Software, Inc.
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* Copyright (c) 2012 Bjørn Mork <bjorn@mork.no>
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*
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* This driver is based on and reuse most of cdc_ncm, which is
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* Copyright (C) ST-Ericsson 2010-2012
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/ethtool.h>
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#include <linux/if_vlan.h>
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#include <linux/ip.h>
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#include <linux/mii.h>
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#include <linux/usb.h>
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#include <linux/usb/cdc.h>
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#include <linux/usb/usbnet.h>
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#include <linux/usb/cdc-wdm.h>
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#include <linux/usb/cdc_ncm.h>
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/* driver specific data - must match cdc_ncm usage */
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struct cdc_mbim_state {
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struct cdc_ncm_ctx *ctx;
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atomic_t pmcount;
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struct usb_driver *subdriver;
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struct usb_interface *control;
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struct usb_interface *data;
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};
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/* using a counter to merge subdriver requests with our own into a combined state */
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static int cdc_mbim_manage_power(struct usbnet *dev, int on)
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{
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struct cdc_mbim_state *info = (void *)&dev->data;
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int rv = 0;
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dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__, atomic_read(&info->pmcount), on);
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if ((on && atomic_add_return(1, &info->pmcount) == 1) || (!on && atomic_dec_and_test(&info->pmcount))) {
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/* need autopm_get/put here to ensure the usbcore sees the new value */
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rv = usb_autopm_get_interface(dev->intf);
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if (rv < 0)
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goto err;
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dev->intf->needs_remote_wakeup = on;
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usb_autopm_put_interface(dev->intf);
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}
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err:
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return rv;
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}
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static int cdc_mbim_wdm_manage_power(struct usb_interface *intf, int status)
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{
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struct usbnet *dev = usb_get_intfdata(intf);
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/* can be called while disconnecting */
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if (!dev)
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return 0;
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return cdc_mbim_manage_power(dev, status);
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}
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static int cdc_mbim_bind(struct usbnet *dev, struct usb_interface *intf)
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{
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struct cdc_ncm_ctx *ctx;
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struct usb_driver *subdriver = ERR_PTR(-ENODEV);
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int ret = -ENODEV;
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u8 data_altsetting = CDC_NCM_DATA_ALTSETTING_NCM;
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struct cdc_mbim_state *info = (void *)&dev->data;
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/* see if interface supports MBIM alternate setting */
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if (intf->num_altsetting == 2) {
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if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
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usb_set_interface(dev->udev,
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intf->cur_altsetting->desc.bInterfaceNumber,
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CDC_NCM_COMM_ALTSETTING_MBIM);
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data_altsetting = CDC_NCM_DATA_ALTSETTING_MBIM;
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}
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/* Probably NCM, defer for cdc_ncm_bind */
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if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
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goto err;
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ret = cdc_ncm_bind_common(dev, intf, data_altsetting);
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if (ret)
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goto err;
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ctx = info->ctx;
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/* The MBIM descriptor and the status endpoint are required */
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if (ctx->mbim_desc && dev->status)
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subdriver = usb_cdc_wdm_register(ctx->control,
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&dev->status->desc,
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le16_to_cpu(ctx->mbim_desc->wMaxControlMessage),
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cdc_mbim_wdm_manage_power);
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if (IS_ERR(subdriver)) {
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ret = PTR_ERR(subdriver);
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cdc_ncm_unbind(dev, intf);
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goto err;
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}
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/* can't let usbnet use the interrupt endpoint */
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dev->status = NULL;
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info->subdriver = subdriver;
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/* MBIM cannot do ARP */
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dev->net->flags |= IFF_NOARP;
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/* no need to put the VLAN tci in the packet headers */
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dev->net->features |= NETIF_F_HW_VLAN_TX;
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err:
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return ret;
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}
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static void cdc_mbim_unbind(struct usbnet *dev, struct usb_interface *intf)
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{
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struct cdc_mbim_state *info = (void *)&dev->data;
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struct cdc_ncm_ctx *ctx = info->ctx;
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/* disconnect subdriver from control interface */
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if (info->subdriver && info->subdriver->disconnect)
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info->subdriver->disconnect(ctx->control);
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info->subdriver = NULL;
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/* let NCM unbind clean up both control and data interface */
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cdc_ncm_unbind(dev, intf);
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}
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static struct sk_buff *cdc_mbim_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
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{
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struct sk_buff *skb_out;
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struct cdc_mbim_state *info = (void *)&dev->data;
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struct cdc_ncm_ctx *ctx = info->ctx;
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__le32 sign = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN);
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u16 tci = 0;
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u8 *c;
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if (!ctx)
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goto error;
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if (skb) {
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if (skb->len <= sizeof(ETH_HLEN))
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goto error;
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/* mapping VLANs to MBIM sessions:
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* no tag => IPS session <0>
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* 1 - 255 => IPS session <vlanid>
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* 256 - 511 => DSS session <vlanid - 256>
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* 512 - 4095 => unsupported, drop
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*/
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vlan_get_tag(skb, &tci);
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switch (tci & 0x0f00) {
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case 0x0000: /* VLAN ID 0 - 255 */
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/* verify that datagram is IPv4 or IPv6 */
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skb_reset_mac_header(skb);
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switch (eth_hdr(skb)->h_proto) {
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case htons(ETH_P_IP):
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case htons(ETH_P_IPV6):
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break;
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default:
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goto error;
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}
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c = (u8 *)&sign;
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c[3] = tci;
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break;
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case 0x0100: /* VLAN ID 256 - 511 */
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sign = cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN);
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c = (u8 *)&sign;
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c[3] = tci;
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break;
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default:
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netif_err(dev, tx_err, dev->net,
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"unsupported tci=0x%04x\n", tci);
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goto error;
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}
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skb_pull(skb, ETH_HLEN);
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}
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spin_lock_bh(&ctx->mtx);
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skb_out = cdc_ncm_fill_tx_frame(ctx, skb, sign);
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spin_unlock_bh(&ctx->mtx);
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return skb_out;
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error:
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if (skb)
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dev_kfree_skb_any(skb);
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return NULL;
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}
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static struct sk_buff *cdc_mbim_process_dgram(struct usbnet *dev, u8 *buf, size_t len, u16 tci)
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{
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__be16 proto = htons(ETH_P_802_3);
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struct sk_buff *skb = NULL;
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if (tci < 256) { /* IPS session? */
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if (len < sizeof(struct iphdr))
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goto err;
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switch (*buf & 0xf0) {
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case 0x40:
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proto = htons(ETH_P_IP);
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break;
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case 0x60:
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proto = htons(ETH_P_IPV6);
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break;
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default:
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goto err;
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}
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}
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skb = netdev_alloc_skb_ip_align(dev->net, len + ETH_HLEN);
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if (!skb)
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goto err;
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/* add an ethernet header */
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skb_put(skb, ETH_HLEN);
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skb_reset_mac_header(skb);
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eth_hdr(skb)->h_proto = proto;
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memset(eth_hdr(skb)->h_source, 0, ETH_ALEN);
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memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN);
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/* add datagram */
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memcpy(skb_put(skb, len), buf, len);
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/* map MBIM session to VLAN */
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if (tci)
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vlan_put_tag(skb, tci);
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err:
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return skb;
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}
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static int cdc_mbim_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
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{
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struct sk_buff *skb;
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struct cdc_mbim_state *info = (void *)&dev->data;
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struct cdc_ncm_ctx *ctx = info->ctx;
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int len;
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int nframes;
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int x;
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int offset;
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struct usb_cdc_ncm_ndp16 *ndp16;
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struct usb_cdc_ncm_dpe16 *dpe16;
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int ndpoffset;
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int loopcount = 50; /* arbitrary max preventing infinite loop */
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u8 *c;
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u16 tci;
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ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
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if (ndpoffset < 0)
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goto error;
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next_ndp:
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nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
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if (nframes < 0)
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goto error;
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ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
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switch (ndp16->dwSignature & cpu_to_le32(0x00ffffff)) {
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case cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN):
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c = (u8 *)&ndp16->dwSignature;
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tci = c[3];
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break;
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case cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN):
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c = (u8 *)&ndp16->dwSignature;
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tci = c[3] + 256;
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break;
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default:
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netif_dbg(dev, rx_err, dev->net,
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"unsupported NDP signature <0x%08x>\n",
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le32_to_cpu(ndp16->dwSignature));
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goto err_ndp;
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}
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dpe16 = ndp16->dpe16;
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for (x = 0; x < nframes; x++, dpe16++) {
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offset = le16_to_cpu(dpe16->wDatagramIndex);
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len = le16_to_cpu(dpe16->wDatagramLength);
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/*
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* CDC NCM ch. 3.7
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* All entries after first NULL entry are to be ignored
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*/
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if ((offset == 0) || (len == 0)) {
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if (!x)
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goto err_ndp; /* empty NTB */
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break;
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}
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/* sanity checking */
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if (((offset + len) > skb_in->len) || (len > ctx->rx_max)) {
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netif_dbg(dev, rx_err, dev->net,
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"invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
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x, offset, len, skb_in);
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if (!x)
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goto err_ndp;
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break;
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} else {
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skb = cdc_mbim_process_dgram(dev, skb_in->data + offset, len, tci);
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if (!skb)
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goto error;
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usbnet_skb_return(dev, skb);
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}
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}
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err_ndp:
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/* are there more NDPs to process? */
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ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
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if (ndpoffset && loopcount--)
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goto next_ndp;
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return 1;
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error:
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return 0;
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}
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static int cdc_mbim_suspend(struct usb_interface *intf, pm_message_t message)
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{
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int ret = 0;
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struct usbnet *dev = usb_get_intfdata(intf);
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struct cdc_mbim_state *info = (void *)&dev->data;
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struct cdc_ncm_ctx *ctx = info->ctx;
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if (ctx == NULL) {
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ret = -1;
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goto error;
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}
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ret = usbnet_suspend(intf, message);
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if (ret < 0)
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goto error;
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if (intf == ctx->control && info->subdriver && info->subdriver->suspend)
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ret = info->subdriver->suspend(intf, message);
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if (ret < 0)
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usbnet_resume(intf);
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error:
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return ret;
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}
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static int cdc_mbim_resume(struct usb_interface *intf)
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{
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int ret = 0;
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struct usbnet *dev = usb_get_intfdata(intf);
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struct cdc_mbim_state *info = (void *)&dev->data;
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struct cdc_ncm_ctx *ctx = info->ctx;
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bool callsub = (intf == ctx->control && info->subdriver && info->subdriver->resume);
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if (callsub)
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ret = info->subdriver->resume(intf);
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if (ret < 0)
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goto err;
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ret = usbnet_resume(intf);
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if (ret < 0 && callsub && info->subdriver->suspend)
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info->subdriver->suspend(intf, PMSG_SUSPEND);
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err:
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return ret;
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}
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static const struct driver_info cdc_mbim_info = {
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.description = "CDC MBIM",
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.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
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.bind = cdc_mbim_bind,
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.unbind = cdc_mbim_unbind,
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.manage_power = cdc_mbim_manage_power,
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.rx_fixup = cdc_mbim_rx_fixup,
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.tx_fixup = cdc_mbim_tx_fixup,
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};
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/* MBIM and NCM devices should not need a ZLP after NTBs with
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* dwNtbOutMaxSize length. This driver_info is for the exceptional
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* devices requiring it anyway, allowing them to be supported without
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* forcing the performance penalty on all the sane devices.
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*/
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static const struct driver_info cdc_mbim_info_zlp = {
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.description = "CDC MBIM",
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.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN | FLAG_SEND_ZLP,
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.bind = cdc_mbim_bind,
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.unbind = cdc_mbim_unbind,
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.manage_power = cdc_mbim_manage_power,
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.rx_fixup = cdc_mbim_rx_fixup,
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.tx_fixup = cdc_mbim_tx_fixup,
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};
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static const struct usb_device_id mbim_devs[] = {
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/* This duplicate NCM entry is intentional. MBIM devices can
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* be disguised as NCM by default, and this is necessary to
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* allow us to bind the correct driver_info to such devices.
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*
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* bind() will sort out this for us, selecting the correct
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* entry and reject the other
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*/
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{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
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.driver_info = (unsigned long)&cdc_mbim_info,
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},
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/* Sierra Wireless MC7710 need ZLPs */
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{ USB_DEVICE_AND_INTERFACE_INFO(0x1199, 0x68a2, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
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.driver_info = (unsigned long)&cdc_mbim_info_zlp,
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},
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{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
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.driver_info = (unsigned long)&cdc_mbim_info,
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},
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{
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},
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};
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MODULE_DEVICE_TABLE(usb, mbim_devs);
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static struct usb_driver cdc_mbim_driver = {
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.name = "cdc_mbim",
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.id_table = mbim_devs,
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.probe = usbnet_probe,
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.disconnect = usbnet_disconnect,
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.suspend = cdc_mbim_suspend,
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.resume = cdc_mbim_resume,
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.reset_resume = cdc_mbim_resume,
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.supports_autosuspend = 1,
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.disable_hub_initiated_lpm = 1,
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};
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module_usb_driver(cdc_mbim_driver);
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MODULE_AUTHOR("Greg Suarez <gsuarez@smithmicro.com>");
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MODULE_AUTHOR("Bjørn Mork <bjorn@mork.no>");
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MODULE_DESCRIPTION("USB CDC MBIM host driver");
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MODULE_LICENSE("GPL");
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