xref: /linux/net/caif/caif_usb.c (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e)
1 /*
2  * CAIF USB handler
3  * Copyright (C) ST-Ericsson AB 2011
4  * Author:	Sjur Brendeland/sjur.brandeland@stericsson.com
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 <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 to 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 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 		pr_warn("Out of memory\n");
91 		return NULL;
92 	}
93 	caif_assert(offsetof(struct cfusbl, layer) == 0);
94 
95 	memset(this, 0, sizeof(struct cflayer));
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 	memcpy(&this->tx_eth_hdr[ETH_ALEN], braddr, ETH_ALEN);
109 	memcpy(&this->tx_eth_hdr[ETH_ALEN], ethaddr, ETH_ALEN);
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 
119 static struct packet_type caif_usb_type __read_mostly = {
120 	.type = cpu_to_be16(ETH_P_802_EX1),
121 };
122 
123 static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
124 			      void *arg)
125 {
126 	struct net_device *dev = arg;
127 	struct caif_dev_common common;
128 	struct cflayer *layer, *link_support;
129 	struct usbnet	*usbnet = netdev_priv(dev);
130 	struct usb_device	*usbdev = usbnet->udev;
131 	struct ethtool_drvinfo drvinfo;
132 
133 	/*
134 	 * Quirks: High-jack ethtool to find if we have a NCM device,
135 	 * and find it's VID/PID.
136 	 */
137 	if (dev->ethtool_ops == NULL || dev->ethtool_ops->get_drvinfo == NULL)
138 		return 0;
139 
140 	dev->ethtool_ops->get_drvinfo(dev, &drvinfo);
141 	if (strncmp(drvinfo.driver, "cdc_ncm", 7) != 0)
142 		return 0;
143 
144 	pr_debug("USB CDC NCM device VID:0x%4x PID:0x%4x\n",
145 		le16_to_cpu(usbdev->descriptor.idVendor),
146 		le16_to_cpu(usbdev->descriptor.idProduct));
147 
148 	/* Check for VID/PID that supports CAIF */
149 	if (!(le16_to_cpu(usbdev->descriptor.idVendor) == STE_USB_VID &&
150 		le16_to_cpu(usbdev->descriptor.idProduct) == STE_USB_PID_CAIF))
151 		return 0;
152 
153 	if (what == NETDEV_UNREGISTER)
154 		module_put(THIS_MODULE);
155 
156 	if (what != NETDEV_REGISTER)
157 		return 0;
158 
159 	__module_get(THIS_MODULE);
160 
161 	memset(&common, 0, sizeof(common));
162 	common.use_frag = false;
163 	common.use_fcs = false;
164 	common.use_stx = false;
165 	common.link_select = CAIF_LINK_HIGH_BANDW;
166 	common.flowctrl = NULL;
167 
168 	link_support = cfusbl_create(dev->ifindex, dev->dev_addr,
169 					dev->broadcast);
170 
171 	if (!link_support)
172 		return -ENOMEM;
173 
174 	if (dev->num_tx_queues > 1)
175 		pr_warn("USB device uses more than one tx queue\n");
176 
177 	caif_enroll_dev(dev, &common, link_support, CFUSB_MAX_HEADLEN,
178 			&layer, &caif_usb_type.func);
179 	if (!pack_added)
180 		dev_add_pack(&caif_usb_type);
181 	pack_added = true;
182 
183 	strncpy(layer->name, dev->name,
184 			sizeof(layer->name) - 1);
185 	layer->name[sizeof(layer->name) - 1] = 0;
186 
187 	return 0;
188 }
189 
190 static struct notifier_block caif_device_notifier = {
191 	.notifier_call = cfusbl_device_notify,
192 	.priority = 0,
193 };
194 
195 static int __init cfusbl_init(void)
196 {
197 	return register_netdevice_notifier(&caif_device_notifier);
198 }
199 
200 static void __exit cfusbl_exit(void)
201 {
202 	unregister_netdevice_notifier(&caif_device_notifier);
203 	dev_remove_pack(&caif_usb_type);
204 }
205 
206 module_init(cfusbl_init);
207 module_exit(cfusbl_exit);
208