1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * GeneSys GL620USB-A based links
4 * Copyright (C) 2001 by Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
5 * Copyright (C) 2001 by Stanislav Brabec <utx@penguin.cz>
6 */
7
8 // #define DEBUG // error path messages, extra info
9 // #define VERBOSE // more; success messages
10
11 #include <linux/module.h>
12 #include <linux/netdevice.h>
13 #include <linux/etherdevice.h>
14 #include <linux/ethtool.h>
15 #include <linux/workqueue.h>
16 #include <linux/mii.h>
17 #include <linux/usb.h>
18 #include <linux/usb/usbnet.h>
19 #include <linux/gfp.h>
20
21
22 /*
23 * GeneSys GL620USB-A (www.genesyslogic.com.tw)
24 *
25 * ... should partially interop with the Win32 driver for this hardware.
26 * The GeneSys docs imply there's some NDIS issue motivating this framing.
27 *
28 * Some info from GeneSys:
29 * - GL620USB-A is full duplex; GL620USB is only half duplex for bulk.
30 * (Some cables, like the BAFO-100c, use the half duplex version.)
31 * - For the full duplex model, the low bit of the version code says
32 * which side is which ("left/right").
33 * - For the half duplex type, a control/interrupt handshake settles
34 * the transfer direction. (That's disabled here, partially coded.)
35 * A control URB would block until other side writes an interrupt.
36 *
37 * Original code from Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
38 * and merged into "usbnet" by Stanislav Brabec <utx@penguin.cz>.
39 */
40
41 // control msg write command
42 #define GENELINK_CONNECT_WRITE 0xF0
43 // interrupt pipe index
44 #define GENELINK_INTERRUPT_PIPE 0x03
45 // interrupt read buffer size
46 #define INTERRUPT_BUFSIZE 0x08
47 // interrupt pipe interval value
48 #define GENELINK_INTERRUPT_INTERVAL 0x10
49 // max transmit packet number per transmit
50 #define GL_MAX_TRANSMIT_PACKETS 32
51 // max packet length
52 #define GL_MAX_PACKET_LEN 1514
53 // max receive buffer size
54 #define GL_RCV_BUF_SIZE \
55 (((GL_MAX_PACKET_LEN + 4) * GL_MAX_TRANSMIT_PACKETS) + 4)
56
57 struct gl_packet {
58 __le32 packet_length;
59 char packet_data [1];
60 };
61
62 struct gl_header {
63 __le32 packet_count;
64 struct gl_packet packets;
65 };
66
genelink_rx_fixup(struct usbnet * dev,struct sk_buff * skb)67 static int genelink_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
68 {
69 struct gl_header *header;
70 struct gl_packet *packet;
71 struct sk_buff *gl_skb;
72 u32 size;
73 u32 count;
74
75 /* This check is no longer done by usbnet */
76 if (skb->len < dev->net->hard_header_len)
77 return 0;
78
79 header = (struct gl_header *) skb->data;
80
81 // get the packet count of the received skb
82 count = le32_to_cpu(header->packet_count);
83 if (count > GL_MAX_TRANSMIT_PACKETS) {
84 netdev_dbg(dev->net,
85 "genelink: invalid received packet count %u\n",
86 count);
87 return 0;
88 }
89
90 // set the current packet pointer to the first packet
91 packet = &header->packets;
92
93 // decrement the length for the packet count size 4 bytes
94 skb_pull(skb, 4);
95
96 while (count > 1) {
97 // get the packet length
98 size = le32_to_cpu(packet->packet_length);
99
100 // this may be a broken packet
101 if (size > GL_MAX_PACKET_LEN) {
102 netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
103 size);
104 return 0;
105 }
106
107 // allocate the skb for the individual packet
108 gl_skb = alloc_skb(size, GFP_ATOMIC);
109 if (gl_skb) {
110
111 // copy the packet data to the new skb
112 skb_put_data(gl_skb, packet->packet_data, size);
113 usbnet_skb_return(dev, gl_skb);
114 }
115
116 // advance to the next packet
117 packet = (struct gl_packet *)&packet->packet_data[size];
118 count--;
119
120 // shift the data pointer to the next gl_packet
121 skb_pull(skb, size + 4);
122 }
123
124 // skip the packet length field 4 bytes
125 skb_pull(skb, 4);
126
127 if (skb->len > GL_MAX_PACKET_LEN) {
128 netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
129 skb->len);
130 return 0;
131 }
132 return 1;
133 }
134
135 static struct sk_buff *
genelink_tx_fixup(struct usbnet * dev,struct sk_buff * skb,gfp_t flags)136 genelink_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
137 {
138 int padlen;
139 int length = skb->len;
140 int headroom = skb_headroom(skb);
141 int tailroom = skb_tailroom(skb);
142 __le32 *packet_count;
143 __le32 *packet_len;
144
145 // FIXME: magic numbers, bleech
146 padlen = ((skb->len + (4 + 4*1)) % 64) ? 0 : 1;
147
148 if ((!skb_cloned(skb))
149 && ((headroom + tailroom) >= (padlen + (4 + 4*1)))) {
150 if ((headroom < (4 + 4*1)) || (tailroom < padlen)) {
151 skb->data = memmove(skb->head + (4 + 4*1),
152 skb->data, skb->len);
153 skb_set_tail_pointer(skb, skb->len);
154 }
155 } else {
156 struct sk_buff *skb2;
157 skb2 = skb_copy_expand(skb, (4 + 4*1) , padlen, flags);
158 dev_kfree_skb_any(skb);
159 skb = skb2;
160 if (!skb)
161 return NULL;
162 }
163
164 // attach the packet count to the header
165 packet_count = skb_push(skb, (4 + 4 * 1));
166 packet_len = packet_count + 1;
167
168 *packet_count = cpu_to_le32(1);
169 *packet_len = cpu_to_le32(length);
170
171 // add padding byte
172 if ((skb->len % dev->maxpacket) == 0)
173 skb_put(skb, 1);
174
175 return skb;
176 }
177
genelink_bind(struct usbnet * dev,struct usb_interface * intf)178 static int genelink_bind(struct usbnet *dev, struct usb_interface *intf)
179 {
180 dev->hard_mtu = GL_RCV_BUF_SIZE;
181 dev->net->hard_header_len += 4;
182 dev->in = usb_rcvbulkpipe(dev->udev, dev->driver_info->in);
183 dev->out = usb_sndbulkpipe(dev->udev, dev->driver_info->out);
184 return 0;
185 }
186
187 static const struct driver_info genelink_info = {
188 .description = "Genesys GeneLink",
189 .flags = FLAG_POINTTOPOINT | FLAG_FRAMING_GL | FLAG_NO_SETINT,
190 .bind = genelink_bind,
191 .rx_fixup = genelink_rx_fixup,
192 .tx_fixup = genelink_tx_fixup,
193
194 .in = 1, .out = 2,
195
196 #ifdef GENELINK_ACK
197 .check_connect =genelink_check_connect,
198 #endif
199 };
200
201 static const struct usb_device_id products [] = {
202
203 {
204 USB_DEVICE(0x05e3, 0x0502), // GL620USB-A
205 .driver_info = (unsigned long) &genelink_info,
206 },
207 /* NOT: USB_DEVICE(0x05e3, 0x0501), // GL620USB
208 * that's half duplex, not currently supported
209 */
210 { }, // END
211 };
212 MODULE_DEVICE_TABLE(usb, products);
213
214 static struct usb_driver gl620a_driver = {
215 .name = "gl620a",
216 .id_table = products,
217 .probe = usbnet_probe,
218 .disconnect = usbnet_disconnect,
219 .suspend = usbnet_suspend,
220 .resume = usbnet_resume,
221 .disable_hub_initiated_lpm = 1,
222 };
223
224 module_usb_driver(gl620a_driver);
225
226 MODULE_AUTHOR("Jiun-Jie Huang");
227 MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
228 MODULE_LICENSE("GPL");
229
230