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_DESCRIPTION("ST-Ericsson CAIF modem protocol USB support");
24 MODULE_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
32 struct cfusbl {
33 struct cflayer layer;
34 u8 tx_eth_hdr[ETH_HLEN];
35 };
36
37 static bool pack_added;
38
39 static 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
49 static 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 too 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
78 static 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
85 static struct cflayer *cfusbl_create(int phyid, const 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
119 static void cfusbl_release(struct cflayer *layer)
120 {
121 kfree(layer);
122 }
123
124 static struct packet_type caif_usb_type __read_mostly = {
125 .type = cpu_to_be16(ETH_P_802_EX1),
126 };
127
128 static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
129 void *ptr)
130 {
131 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
132 struct caif_dev_common common;
133 struct cflayer *layer, *link_support;
134 struct usbnet *usbnet;
135 struct usb_device *usbdev;
136 int res;
137
138 if (what == NETDEV_UNREGISTER && dev->reg_state >= NETREG_UNREGISTERED)
139 return 0;
140
141 /* Check whether we have a NCM device, and find its VID/PID. */
142 if (!(dev->dev.parent && dev->dev.parent->driver &&
143 strcmp(dev->dev.parent->driver->name, "cdc_ncm") == 0))
144 return 0;
145
146 usbnet = netdev_priv(dev);
147 usbdev = usbnet->udev;
148
149 pr_debug("USB CDC NCM device VID:0x%4x PID:0x%4x\n",
150 le16_to_cpu(usbdev->descriptor.idVendor),
151 le16_to_cpu(usbdev->descriptor.idProduct));
152
153 /* Check for VID/PID that supports CAIF */
154 if (!(le16_to_cpu(usbdev->descriptor.idVendor) == STE_USB_VID &&
155 le16_to_cpu(usbdev->descriptor.idProduct) == STE_USB_PID_CAIF))
156 return 0;
157
158 if (what == NETDEV_UNREGISTER)
159 module_put(THIS_MODULE);
160
161 if (what != NETDEV_REGISTER)
162 return 0;
163
164 __module_get(THIS_MODULE);
165
166 memset(&common, 0, sizeof(common));
167 common.use_frag = false;
168 common.use_fcs = false;
169 common.use_stx = false;
170 common.link_select = CAIF_LINK_HIGH_BANDW;
171 common.flowctrl = NULL;
172
173 link_support = cfusbl_create(dev->ifindex, dev->dev_addr,
174 dev->broadcast);
175
176 if (!link_support)
177 return -ENOMEM;
178
179 if (dev->num_tx_queues > 1)
180 pr_warn("USB device uses more than one tx queue\n");
181
182 res = caif_enroll_dev(dev, &common, link_support, CFUSB_MAX_HEADLEN,
183 &layer, &caif_usb_type.func);
184 if (res)
185 goto err;
186
187 if (!pack_added)
188 dev_add_pack(&caif_usb_type);
189 pack_added = true;
190
191 strscpy(layer->name, dev->name, sizeof(layer->name));
192
193 return 0;
194 err:
195 cfusbl_release(link_support);
196 return res;
197 }
198
199 static struct notifier_block caif_device_notifier = {
200 .notifier_call = cfusbl_device_notify,
201 .priority = 0,
202 };
203
204 static int __init cfusbl_init(void)
205 {
206 return register_netdevice_notifier(&caif_device_notifier);
207 }
208
209 static void __exit cfusbl_exit(void)
210 {
211 unregister_netdevice_notifier(&caif_device_notifier);
212 dev_remove_pack(&caif_usb_type);
213 }
214
215 module_init(cfusbl_init);
216 module_exit(cfusbl_exit);
217
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