net/caif/caif_usb.c

   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
  23 MODULE_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
  31 struct cfusbl {
  32         struct cflayer layer;
  33         u8 tx_eth_hdr[ETH_HLEN];
  34 };
  35
  36 static bool pack_added;
  37
  38 static 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
  48 static 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
  77 static 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
  84 static 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
 118 static void cfusbl_release(struct cflayer *layer)
 119 {
 120         kfree(layer);
 121 }
 122
 123 static struct packet_type caif_usb_type __read_mostly = {
 124         .type = cpu_to_be16(ETH_P_802_EX1),
 125 };
 126
 127 static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
 128                                 void *ptr)
 129 {
 130         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 131         struct caif_dev_common common;
 132         struct cflayer *layer, *link_support;
 133         struct usbnet *usbnet;
 134         struct usb_device *usbdev;
 135         int res;
 136
 137         /* Check whether we have a NCM device, and find its VID/PID. */
 138         if (!(dev->dev.parent && dev->dev.parent->driver &&
 139               strcmp(dev->dev.parent->driver->name, "cdc_ncm") == 0))
 140                 return 0;
 141
 142         usbnet = netdev_priv(dev);
 143         usbdev = usbnet->udev;
 144
 145         pr_debug("USB CDC NCM device VID:0x%4x PID:0x%4x\n",
 146                 le16_to_cpu(usbdev->descriptor.idVendor),
 147                 le16_to_cpu(usbdev->descriptor.idProduct));
 148
 149         /* Check for VID/PID that supports CAIF */
 150         if (!(le16_to_cpu(usbdev->descriptor.idVendor) == STE_USB_VID &&
 151                 le16_to_cpu(usbdev->descriptor.idProduct) == STE_USB_PID_CAIF))
 152                 return 0;
 153
 154         if (what == NETDEV_UNREGISTER)
 155                 module_put(THIS_MODULE);
 156
 157         if (what != NETDEV_REGISTER)
 158                 return 0;
 159
 160         __module_get(THIS_MODULE);
 161
 162         memset(&common, 0, sizeof(common));
 163         common.use_frag = false;
 164         common.use_fcs = false;
 165         common.use_stx = false;
 166         common.link_select = CAIF_LINK_HIGH_BANDW;
 167         common.flowctrl = NULL;
 168
 169         link_support = cfusbl_create(dev->ifindex, dev->dev_addr,
 170                                         dev->broadcast);
 171
 172         if (!link_support)
 173                 return -ENOMEM;
 174
 175         if (dev->num_tx_queues > 1)
 176                 pr_warn("USB device uses more than one tx queue\n");
 177
 178         res = caif_enroll_dev(dev, &common, link_support, CFUSB_MAX_HEADLEN,
 179                         &layer, &caif_usb_type.func);
 180         if (res)
 181                 goto err;
 182
 183         if (!pack_added)
 184                 dev_add_pack(&caif_usb_type);
 185         pack_added = true;
 186
 187         strlcpy(layer->name, dev->name, sizeof(layer->name));
 188
 189         return 0;
 190 err:
 191         cfusbl_release(link_support);
 192         return res;
 193 }
 194
 195 static struct notifier_block caif_device_notifier = {
 196         .notifier_call = cfusbl_device_notify,
 197         .priority = 0,
 198 };
 199
 200 static int __init cfusbl_init(void)
 201 {
 202         return register_netdevice_notifier(&caif_device_notifier);
 203 }
 204
 205 static void __exit cfusbl_exit(void)
 206 {
 207         unregister_netdevice_notifier(&caif_device_notifier);
 208         dev_remove_pack(&caif_usb_type);
 209 }
 210
 211 module_init(cfusbl_init);
 212 module_exit(cfusbl_exit);