net/caif/caif_usb.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * CAIF USB handler
0004  * Copyright (C) ST-Ericsson AB 2011
0005  * Author:  Sjur Brendeland
0006  */
0007
0008 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
0009
0010 #include <linux/module.h>
0011 #include <linux/netdevice.h>
0012 #include <linux/slab.h>
0013 #include <linux/mii.h>
0014 #include <linux/usb.h>
0015 #include <linux/usb/usbnet.h>
0016 #include <linux/etherdevice.h>
0017 #include <net/netns/generic.h>
0018 #include <net/caif/caif_dev.h>
0019 #include <net/caif/caif_layer.h>
0020 #include <net/caif/cfpkt.h>
0021 #include <net/caif/cfcnfg.h>
0022
0023 MODULE_LICENSE("GPL");
0024
0025 #define CFUSB_PAD_DESCR_SZ 1    /* Alignment descriptor length */
0026 #define CFUSB_ALIGNMENT 4   /* Number of bytes to align. */
0027 #define CFUSB_MAX_HEADLEN (CFUSB_PAD_DESCR_SZ + CFUSB_ALIGNMENT-1)
0028 #define STE_USB_VID 0x04cc  /* USB Product ID for ST-Ericsson */
0029 #define STE_USB_PID_CAIF 0x230f /* Product id for CAIF Modems */
0030
0031 struct cfusbl {
0032     struct cflayer layer;
0033     u8 tx_eth_hdr[ETH_HLEN];
0034 };
0035
0036 static bool pack_added;
0037
0038 static int cfusbl_receive(struct cflayer *layr, struct cfpkt *pkt)
0039 {
0040     u8 hpad;
0041
0042     /* Remove padding. */
0043     cfpkt_extr_head(pkt, &hpad, 1);
0044     cfpkt_extr_head(pkt, NULL, hpad);
0045     return layr->up->receive(layr->up, pkt);
0046 }
0047
0048 static int cfusbl_transmit(struct cflayer *layr, struct cfpkt *pkt)
0049 {
0050     struct caif_payload_info *info;
0051     u8 hpad;
0052     u8 zeros[CFUSB_ALIGNMENT];
0053     struct sk_buff *skb;
0054     struct cfusbl *usbl = container_of(layr, struct cfusbl, layer);
0055
0056     skb = cfpkt_tonative(pkt);
0057
0058     skb_reset_network_header(skb);
0059     skb->protocol = htons(ETH_P_IP);
0060
0061     info = cfpkt_info(pkt);
0062     hpad = (info->hdr_len + CFUSB_PAD_DESCR_SZ) & (CFUSB_ALIGNMENT - 1);
0063
0064     if (skb_headroom(skb) < ETH_HLEN + CFUSB_PAD_DESCR_SZ + hpad) {
0065         pr_warn("Headroom too small\n");
0066         kfree_skb(skb);
0067         return -EIO;
0068     }
0069     memset(zeros, 0, hpad);
0070
0071     cfpkt_add_head(pkt, zeros, hpad);
0072     cfpkt_add_head(pkt, &hpad, 1);
0073     cfpkt_add_head(pkt, usbl->tx_eth_hdr, sizeof(usbl->tx_eth_hdr));
0074     return layr->dn->transmit(layr->dn, pkt);
0075 }
0076
0077 static void cfusbl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
0078                int phyid)
0079 {
0080     if (layr->up && layr->up->ctrlcmd)
0081         layr->up->ctrlcmd(layr->up, ctrl, layr->id);
0082 }
0083
0084 static struct cflayer *cfusbl_create(int phyid, const u8 ethaddr[ETH_ALEN],
0085                       u8 braddr[ETH_ALEN])
0086 {
0087     struct cfusbl *this = kmalloc(sizeof(struct cfusbl), GFP_ATOMIC);
0088
0089     if (!this)
0090         return NULL;
0091
0092     caif_assert(offsetof(struct cfusbl, layer) == 0);
0093
0094     memset(&this->layer, 0, sizeof(this->layer));
0095     this->layer.receive = cfusbl_receive;
0096     this->layer.transmit = cfusbl_transmit;
0097     this->layer.ctrlcmd = cfusbl_ctrlcmd;
0098     snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "usb%d", phyid);
0099     this->layer.id = phyid;
0100
0101     /*
0102      * Construct TX ethernet header:
0103      *  0-5 destination address
0104      *  5-11    source address
0105      *  12-13   protocol type
0106      */
0107     ether_addr_copy(&this->tx_eth_hdr[ETH_ALEN], braddr);
0108     ether_addr_copy(&this->tx_eth_hdr[ETH_ALEN], ethaddr);
0109     this->tx_eth_hdr[12] = cpu_to_be16(ETH_P_802_EX1) & 0xff;
0110     this->tx_eth_hdr[13] = (cpu_to_be16(ETH_P_802_EX1) >> 8) & 0xff;
0111     pr_debug("caif ethernet TX-header dst:%pM src:%pM type:%02x%02x\n",
0112             this->tx_eth_hdr, this->tx_eth_hdr + ETH_ALEN,
0113             this->tx_eth_hdr[12], this->tx_eth_hdr[13]);
0114
0115     return (struct cflayer *) this;
0116 }
0117
0118 static void cfusbl_release(struct cflayer *layer)
0119 {
0120     kfree(layer);
0121 }
0122
0123 static struct packet_type caif_usb_type __read_mostly = {
0124     .type = cpu_to_be16(ETH_P_802_EX1),
0125 };
0126
0127 static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
0128                 void *ptr)
0129 {
0130     struct net_device *dev = netdev_notifier_info_to_dev(ptr);
0131     struct caif_dev_common common;
0132     struct cflayer *layer, *link_support;
0133     struct usbnet *usbnet;
0134     struct usb_device *usbdev;
0135     int res;
0136
0137     /* Check whether we have a NCM device, and find its VID/PID. */
0138     if (!(dev->dev.parent && dev->dev.parent->driver &&
0139           strcmp(dev->dev.parent->driver->name, "cdc_ncm") == 0))
0140         return 0;
0141
0142     usbnet = netdev_priv(dev);
0143     usbdev = usbnet->udev;
0144
0145     pr_debug("USB CDC NCM device VID:0x%4x PID:0x%4x\n",
0146         le16_to_cpu(usbdev->descriptor.idVendor),
0147         le16_to_cpu(usbdev->descriptor.idProduct));
0148
0149     /* Check for VID/PID that supports CAIF */
0150     if (!(le16_to_cpu(usbdev->descriptor.idVendor) == STE_USB_VID &&
0151         le16_to_cpu(usbdev->descriptor.idProduct) == STE_USB_PID_CAIF))
0152         return 0;
0153
0154     if (what == NETDEV_UNREGISTER)
0155         module_put(THIS_MODULE);
0156
0157     if (what != NETDEV_REGISTER)
0158         return 0;
0159
0160     __module_get(THIS_MODULE);
0161
0162     memset(&common, 0, sizeof(common));
0163     common.use_frag = false;
0164     common.use_fcs = false;
0165     common.use_stx = false;
0166     common.link_select = CAIF_LINK_HIGH_BANDW;
0167     common.flowctrl = NULL;
0168
0169     link_support = cfusbl_create(dev->ifindex, dev->dev_addr,
0170                     dev->broadcast);
0171
0172     if (!link_support)
0173         return -ENOMEM;
0174
0175     if (dev->num_tx_queues > 1)
0176         pr_warn("USB device uses more than one tx queue\n");
0177
0178     res = caif_enroll_dev(dev, &common, link_support, CFUSB_MAX_HEADLEN,
0179             &layer, &caif_usb_type.func);
0180     if (res)
0181         goto err;
0182
0183     if (!pack_added)
0184         dev_add_pack(&caif_usb_type);
0185     pack_added = true;
0186
0187     strlcpy(layer->name, dev->name, sizeof(layer->name));
0188
0189     return 0;
0190 err:
0191     cfusbl_release(link_support);
0192     return res;
0193 }
0194
0195 static struct notifier_block caif_device_notifier = {
0196     .notifier_call = cfusbl_device_notify,
0197     .priority = 0,
0198 };
0199
0200 static int __init cfusbl_init(void)
0201 {
0202     return register_netdevice_notifier(&caif_device_notifier);
0203 }
0204
0205 static void __exit cfusbl_exit(void)
0206 {
0207     unregister_netdevice_notifier(&caif_device_notifier);
0208     dev_remove_pack(&caif_usb_type);
0209 }
0210
0211 module_init(cfusbl_init);
0212 module_exit(cfusbl_exit);