1/*
2 * CAIF USB handler
3 * Copyright (C) ST-Ericsson AB 2011
4 * Author:	Sjur Brendeland
5 * License terms: GNU General Public License (GPL) version 2
6 *
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
10
11#include <linux/module.h>
12#include <linux/netdevice.h>
13#include <linux/slab.h>
14#include <linux/mii.h>
15#include <linux/usb.h>
16#include <linux/usb/usbnet.h>
17#include <linux/etherdevice.h>
18#include <net/netns/generic.h>
19#include <net/caif/caif_dev.h>
20#include <net/caif/caif_layer.h>
21#include <net/caif/cfpkt.h>
22#include <net/caif/cfcnfg.h>
23
24MODULE_LICENSE("GPL");
25
26#define CFUSB_PAD_DESCR_SZ 1	/* Alignment descriptor length */
27#define CFUSB_ALIGNMENT 4	/* Number of bytes to align. */
28#define CFUSB_MAX_HEADLEN (CFUSB_PAD_DESCR_SZ + CFUSB_ALIGNMENT-1)
29#define STE_USB_VID 0x04cc	/* USB Product ID for ST-Ericsson */
30#define STE_USB_PID_CAIF 0x230f	/* Product id for CAIF Modems */
31
32struct cfusbl {
33	struct cflayer layer;
34	u8 tx_eth_hdr[ETH_HLEN];
35};
36
37static bool pack_added;
38
39static int cfusbl_receive(struct cflayer *layr, struct cfpkt *pkt)
40{
41	u8 hpad;
42
43	/* Remove padding. */
44	cfpkt_extr_head(pkt, &hpad, 1);
45	cfpkt_extr_head(pkt, NULL, hpad);
46	return layr->up->receive(layr->up, pkt);
47}
48
49static int cfusbl_transmit(struct cflayer *layr, struct cfpkt *pkt)
50{
51	struct caif_payload_info *info;
52	u8 hpad;
53	u8 zeros[CFUSB_ALIGNMENT];
54	struct sk_buff *skb;
55	struct cfusbl *usbl = container_of(layr, struct cfusbl, layer);
56
57	skb = cfpkt_tonative(pkt);
58
59	skb_reset_network_header(skb);
60	skb->protocol = htons(ETH_P_IP);
61
62	info = cfpkt_info(pkt);
63	hpad = (info->hdr_len + CFUSB_PAD_DESCR_SZ) & (CFUSB_ALIGNMENT - 1);
64
65	if (skb_headroom(skb) < ETH_HLEN + CFUSB_PAD_DESCR_SZ + hpad) {
66		pr_warn("Headroom to small\n");
67		kfree_skb(skb);
68		return -EIO;
69	}
70	memset(zeros, 0, hpad);
71
72	cfpkt_add_head(pkt, zeros, hpad);
73	cfpkt_add_head(pkt, &hpad, 1);
74	cfpkt_add_head(pkt, usbl->tx_eth_hdr, sizeof(usbl->tx_eth_hdr));
75	return layr->dn->transmit(layr->dn, pkt);
76}
77
78static void cfusbl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
79			   int phyid)
80{
81	if (layr->up && layr->up->ctrlcmd)
82		layr->up->ctrlcmd(layr->up, ctrl, layr->id);
83}
84
85static struct cflayer *cfusbl_create(int phyid, u8 ethaddr[ETH_ALEN],
86				      u8 braddr[ETH_ALEN])
87{
88	struct cfusbl *this = kmalloc(sizeof(struct cfusbl), GFP_ATOMIC);
89
90	if (!this)
91		return NULL;
92
93	caif_assert(offsetof(struct cfusbl, layer) == 0);
94
95	memset(&this->layer, 0, sizeof(this->layer));
96	this->layer.receive = cfusbl_receive;
97	this->layer.transmit = cfusbl_transmit;
98	this->layer.ctrlcmd = cfusbl_ctrlcmd;
99	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "usb%d", phyid);
100	this->layer.id = phyid;
101
102	/*
103	 * Construct TX ethernet header:
104	 *	0-5	destination address
105	 *	5-11	source address
106	 *	12-13	protocol type
107	 */
108	ether_addr_copy(&this->tx_eth_hdr[ETH_ALEN], braddr);
109	ether_addr_copy(&this->tx_eth_hdr[ETH_ALEN], ethaddr);
110	this->tx_eth_hdr[12] = cpu_to_be16(ETH_P_802_EX1) & 0xff;
111	this->tx_eth_hdr[13] = (cpu_to_be16(ETH_P_802_EX1) >> 8) & 0xff;
112	pr_debug("caif ethernet TX-header dst:%pM src:%pM type:%02x%02x\n",
113			this->tx_eth_hdr, this->tx_eth_hdr + ETH_ALEN,
114			this->tx_eth_hdr[12], this->tx_eth_hdr[13]);
115
116	return (struct cflayer *) this;
117}
118
119static struct packet_type caif_usb_type __read_mostly = {
120	.type = cpu_to_be16(ETH_P_802_EX1),
121};
122
123static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
124				void *ptr)
125{
126	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
127	struct caif_dev_common common;
128	struct cflayer *layer, *link_support;
129	struct usbnet *usbnet;
130	struct usb_device *usbdev;
131
132	/* Check whether we have a NCM device, and find its VID/PID. */
133	if (!(dev->dev.parent && dev->dev.parent->driver &&
134	      strcmp(dev->dev.parent->driver->name, "cdc_ncm") == 0))
135		return 0;
136
137	usbnet = netdev_priv(dev);
138	usbdev = usbnet->udev;
139
140	pr_debug("USB CDC NCM device VID:0x%4x PID:0x%4x\n",
141		le16_to_cpu(usbdev->descriptor.idVendor),
142		le16_to_cpu(usbdev->descriptor.idProduct));
143
144	/* Check for VID/PID that supports CAIF */
145	if (!(le16_to_cpu(usbdev->descriptor.idVendor) == STE_USB_VID &&
146		le16_to_cpu(usbdev->descriptor.idProduct) == STE_USB_PID_CAIF))
147		return 0;
148
149	if (what == NETDEV_UNREGISTER)
150		module_put(THIS_MODULE);
151
152	if (what != NETDEV_REGISTER)
153		return 0;
154
155	__module_get(THIS_MODULE);
156
157	memset(&common, 0, sizeof(common));
158	common.use_frag = false;
159	common.use_fcs = false;
160	common.use_stx = false;
161	common.link_select = CAIF_LINK_HIGH_BANDW;
162	common.flowctrl = NULL;
163
164	link_support = cfusbl_create(dev->ifindex, dev->dev_addr,
165					dev->broadcast);
166
167	if (!link_support)
168		return -ENOMEM;
169
170	if (dev->num_tx_queues > 1)
171		pr_warn("USB device uses more than one tx queue\n");
172
173	caif_enroll_dev(dev, &common, link_support, CFUSB_MAX_HEADLEN,
174			&layer, &caif_usb_type.func);
175	if (!pack_added)
176		dev_add_pack(&caif_usb_type);
177	pack_added = true;
178
179	strncpy(layer->name, dev->name,
180			sizeof(layer->name) - 1);
181	layer->name[sizeof(layer->name) - 1] = 0;
182
183	return 0;
184}
185
186static struct notifier_block caif_device_notifier = {
187	.notifier_call = cfusbl_device_notify,
188	.priority = 0,
189};
190
191static int __init cfusbl_init(void)
192{
193	return register_netdevice_notifier(&caif_device_notifier);
194}
195
196static void __exit cfusbl_exit(void)
197{
198	unregister_netdevice_notifier(&caif_device_notifier);
199	dev_remove_pack(&caif_usb_type);
200}
201
202module_init(cfusbl_init);
203module_exit(cfusbl_exit);
204