linux/net/caif/caif_usb.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * CAIF USB handler
   4 * Copyright (C) ST-Ericsson AB 2011
   5 * Author:      Sjur Brendeland
   6 */
   7
   8#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   9
  10#include <linux/module.h>
  11#include <linux/netdevice.h>
  12#include <linux/slab.h>
  13#include <linux/mii.h>
  14#include <linux/usb.h>
  15#include <linux/usb/usbnet.h>
  16#include <linux/etherdevice.h>
  17#include <net/netns/generic.h>
  18#include <net/caif/caif_dev.h>
  19#include <net/caif/caif_layer.h>
  20#include <net/caif/cfpkt.h>
  21#include <net/caif/cfcnfg.h>
  22
  23MODULE_LICENSE("GPL");
  24
  25#define CFUSB_PAD_DESCR_SZ 1    /* Alignment descriptor length */
  26#define CFUSB_ALIGNMENT 4       /* Number of bytes to align. */
  27#define CFUSB_MAX_HEADLEN (CFUSB_PAD_DESCR_SZ + CFUSB_ALIGNMENT-1)
  28#define STE_USB_VID 0x04cc      /* USB Product ID for ST-Ericsson */
  29#define STE_USB_PID_CAIF 0x230f /* Product id for CAIF Modems */
  30
  31struct cfusbl {
  32        struct cflayer layer;
  33        u8 tx_eth_hdr[ETH_HLEN];
  34};
  35
  36static bool pack_added;
  37
  38static int cfusbl_receive(struct cflayer *layr, struct cfpkt *pkt)
  39{
  40        u8 hpad;
  41
  42        /* Remove padding. */
  43        cfpkt_extr_head(pkt, &hpad, 1);
  44        cfpkt_extr_head(pkt, NULL, hpad);
  45        return layr->up->receive(layr->up, pkt);
  46}
  47
  48static int cfusbl_transmit(struct cflayer *layr, struct cfpkt *pkt)
  49{
  50        struct caif_payload_info *info;
  51        u8 hpad;
  52        u8 zeros[CFUSB_ALIGNMENT];
  53        struct sk_buff *skb;
  54        struct cfusbl *usbl = container_of(layr, struct cfusbl, layer);
  55
  56        skb = cfpkt_tonative(pkt);
  57
  58        skb_reset_network_header(skb);
  59        skb->protocol = htons(ETH_P_IP);
  60
  61        info = cfpkt_info(pkt);
  62        hpad = (info->hdr_len + CFUSB_PAD_DESCR_SZ) & (CFUSB_ALIGNMENT - 1);
  63
  64        if (skb_headroom(skb) < ETH_HLEN + CFUSB_PAD_DESCR_SZ + hpad) {
  65                pr_warn("Headroom too small\n");
  66                kfree_skb(skb);
  67                return -EIO;
  68        }
  69        memset(zeros, 0, hpad);
  70
  71        cfpkt_add_head(pkt, zeros, hpad);
  72        cfpkt_add_head(pkt, &hpad, 1);
  73        cfpkt_add_head(pkt, usbl->tx_eth_hdr, sizeof(usbl->tx_eth_hdr));
  74        return layr->dn->transmit(layr->dn, pkt);
  75}
  76
  77static void cfusbl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
  78                           int phyid)
  79{
  80        if (layr->up && layr->up->ctrlcmd)
  81                layr->up->ctrlcmd(layr->up, ctrl, layr->id);
  82}
  83
  84static struct cflayer *cfusbl_create(int phyid, u8 ethaddr[ETH_ALEN],
  85                                      u8 braddr[ETH_ALEN])
  86{
  87        struct cfusbl *this = kmalloc(sizeof(struct cfusbl), GFP_ATOMIC);
  88
  89        if (!this)
  90                return NULL;
  91
  92        caif_assert(offsetof(struct cfusbl, layer) == 0);
  93
  94        memset(&this->layer, 0, sizeof(this->layer));
  95        this->layer.receive = cfusbl_receive;
  96        this->layer.transmit = cfusbl_transmit;
  97        this->layer.ctrlcmd = cfusbl_ctrlcmd;
  98        snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "usb%d", phyid);
  99        this->layer.id = phyid;
 100
 101        /*
 102         * Construct TX ethernet header:
 103         *      0-5     destination address
 104         *      5-11    source address
 105         *      12-13   protocol type
 106         */
 107        ether_addr_copy(&this->tx_eth_hdr[ETH_ALEN], braddr);
 108        ether_addr_copy(&this->tx_eth_hdr[ETH_ALEN], ethaddr);
 109        this->tx_eth_hdr[12] = cpu_to_be16(ETH_P_802_EX1) & 0xff;
 110        this->tx_eth_hdr[13] = (cpu_to_be16(ETH_P_802_EX1) >> 8) & 0xff;
 111        pr_debug("caif ethernet TX-header dst:%pM src:%pM type:%02x%02x\n",
 112                        this->tx_eth_hdr, this->tx_eth_hdr + ETH_ALEN,
 113                        this->tx_eth_hdr[12], this->tx_eth_hdr[13]);
 114
 115        return (struct cflayer *) this;
 116}
 117
 118static struct packet_type caif_usb_type __read_mostly = {
 119        .type = cpu_to_be16(ETH_P_802_EX1),
 120};
 121
 122static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
 123                                void *ptr)
 124{
 125        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 126        struct caif_dev_common common;
 127        struct cflayer *layer, *link_support;
 128        struct usbnet *usbnet;
 129        struct usb_device *usbdev;
 130
 131        /* Check whether we have a NCM device, and find its VID/PID. */
 132        if (!(dev->dev.parent && dev->dev.parent->driver &&
 133              strcmp(dev->dev.parent->driver->name, "cdc_ncm") == 0))
 134                return 0;
 135
 136        usbnet = netdev_priv(dev);
 137        usbdev = usbnet->udev;
 138
 139        pr_debug("USB CDC NCM device VID:0x%4x PID:0x%4x\n",
 140                le16_to_cpu(usbdev->descriptor.idVendor),
 141                le16_to_cpu(usbdev->descriptor.idProduct));
 142
 143        /* Check for VID/PID that supports CAIF */
 144        if (!(le16_to_cpu(usbdev->descriptor.idVendor) == STE_USB_VID &&
 145                le16_to_cpu(usbdev->descriptor.idProduct) == STE_USB_PID_CAIF))
 146                return 0;
 147
 148        if (what == NETDEV_UNREGISTER)
 149                module_put(THIS_MODULE);
 150
 151        if (what != NETDEV_REGISTER)
 152                return 0;
 153
 154        __module_get(THIS_MODULE);
 155
 156        memset(&common, 0, sizeof(common));
 157        common.use_frag = false;
 158        common.use_fcs = false;
 159        common.use_stx = false;
 160        common.link_select = CAIF_LINK_HIGH_BANDW;
 161        common.flowctrl = NULL;
 162
 163        link_support = cfusbl_create(dev->ifindex, dev->dev_addr,
 164                                        dev->broadcast);
 165
 166        if (!link_support)
 167                return -ENOMEM;
 168
 169        if (dev->num_tx_queues > 1)
 170                pr_warn("USB device uses more than one tx queue\n");
 171
 172        caif_enroll_dev(dev, &common, link_support, CFUSB_MAX_HEADLEN,
 173                        &layer, &caif_usb_type.func);
 174        if (!pack_added)
 175                dev_add_pack(&caif_usb_type);
 176        pack_added = true;
 177
 178        strlcpy(layer->name, dev->name, sizeof(layer->name));
 179
 180        return 0;
 181}
 182
 183static struct notifier_block caif_device_notifier = {
 184        .notifier_call = cfusbl_device_notify,
 185        .priority = 0,
 186};
 187
 188static int __init cfusbl_init(void)
 189{
 190        return register_netdevice_notifier(&caif_device_notifier);
 191}
 192
 193static void __exit cfusbl_exit(void)
 194{
 195        unregister_netdevice_notifier(&caif_device_notifier);
 196        dev_remove_pack(&caif_usb_type);
 197}
 198
 199module_init(cfusbl_init);
 200module_exit(cfusbl_exit);
 201