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 struct packet_type caif_usb_type __read_mostly = {
 119         .type = cpu_to_be16(ETH_P_802_EX1),
 120 };
 121
 122 static 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
 183 static struct notifier_block caif_device_notifier = {
 184         .notifier_call = cfusbl_device_notify,
 185         .priority = 0,
 186 };
 187
 188 static int __init cfusbl_init(void)
 189 {
 190         return register_netdevice_notifier(&caif_device_notifier);
 191 }
 192
 193 static void __exit cfusbl_exit(void)
 194 {
 195         unregister_netdevice_notifier(&caif_device_notifier);
 196         dev_remove_pack(&caif_usb_type);
 197 }
 198
 199 module_init(cfusbl_init);
 200 module_exit(cfusbl_exit);