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, data: &hpad, len: 1);
44 cfpkt_extr_head(pkt, NULL, len: 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, data: zeros, len: hpad);
72 cfpkt_add_head(pkt, data: &hpad, len: 1);
73 cfpkt_add_head(pkt, data: usbl->tx_eth_hdr, len: 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, const u8 ethaddr[ETH_ALEN],
85 u8 braddr[ETH_ALEN])
86{
87 struct cfusbl *this = kmalloc(size: 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(buf: this->layer.name, CAIF_LAYER_NAME_SZ, fmt: "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(dst: &this->tx_eth_hdr[ETH_ALEN], src: braddr);
108 ether_addr_copy(dst: &this->tx_eth_hdr[ETH_ALEN], src: 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 void cfusbl_release(struct cflayer *layer)
119{
120 kfree(objp: layer);
121}
122
123static struct packet_type caif_usb_type __read_mostly = {
124 .type = cpu_to_be16(ETH_P_802_EX1),
125};
126
127static 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(info: 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 if (what == NETDEV_UNREGISTER && dev->reg_state >= NETREG_UNREGISTERED)
138 return 0;
139
140 /* Check whether we have a NCM device, and find its VID/PID. */
141 if (!(dev->dev.parent && dev->dev.parent->driver &&
142 strcmp(dev->dev.parent->driver->name, "cdc_ncm") == 0))
143 return 0;
144
145 usbnet = netdev_priv(dev);
146 usbdev = usbnet->udev;
147
148 pr_debug("USB CDC NCM device VID:0x%4x PID:0x%4x\n",
149 le16_to_cpu(usbdev->descriptor.idVendor),
150 le16_to_cpu(usbdev->descriptor.idProduct));
151
152 /* Check for VID/PID that supports CAIF */
153 if (!(le16_to_cpu(usbdev->descriptor.idVendor) == STE_USB_VID &&
154 le16_to_cpu(usbdev->descriptor.idProduct) == STE_USB_PID_CAIF))
155 return 0;
156
157 if (what == NETDEV_UNREGISTER)
158 module_put(THIS_MODULE);
159
160 if (what != NETDEV_REGISTER)
161 return 0;
162
163 __module_get(THIS_MODULE);
164
165 memset(&common, 0, sizeof(common));
166 common.use_frag = false;
167 common.use_fcs = false;
168 common.use_stx = false;
169 common.link_select = CAIF_LINK_HIGH_BANDW;
170 common.flowctrl = NULL;
171
172 link_support = cfusbl_create(phyid: dev->ifindex, ethaddr: dev->dev_addr,
173 braddr: dev->broadcast);
174
175 if (!link_support)
176 return -ENOMEM;
177
178 if (dev->num_tx_queues > 1)
179 pr_warn("USB device uses more than one tx queue\n");
180
181 res = caif_enroll_dev(dev, caifdev: &common, link_support, CFUSB_MAX_HEADLEN,
182 layer: &layer, rcv_func: &caif_usb_type.func);
183 if (res)
184 goto err;
185
186 if (!pack_added)
187 dev_add_pack(pt: &caif_usb_type);
188 pack_added = true;
189
190 strscpy(p: layer->name, q: dev->name, size: sizeof(layer->name));
191
192 return 0;
193err:
194 cfusbl_release(layer: link_support);
195 return res;
196}
197
198static struct notifier_block caif_device_notifier = {
199 .notifier_call = cfusbl_device_notify,
200 .priority = 0,
201};
202
203static int __init cfusbl_init(void)
204{
205 return register_netdevice_notifier(nb: &caif_device_notifier);
206}
207
208static void __exit cfusbl_exit(void)
209{
210 unregister_netdevice_notifier(nb: &caif_device_notifier);
211 dev_remove_pack(pt: &caif_usb_type);
212}
213
214module_init(cfusbl_init);
215module_exit(cfusbl_exit);
216

source code of linux/net/caif/caif_usb.c