1/*
2 * GeneSys GL620USB-A based links
3 * Copyright (C) 2001 by Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
4 * Copyright (C) 2001 by Stanislav Brabec <utx@penguin.cz>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19
20// #define	DEBUG			// error path messages, extra info
21// #define	VERBOSE			// more; success messages
22
23#include <linux/module.h>
24#include <linux/netdevice.h>
25#include <linux/etherdevice.h>
26#include <linux/ethtool.h>
27#include <linux/workqueue.h>
28#include <linux/mii.h>
29#include <linux/usb.h>
30#include <linux/usb/usbnet.h>
31#include <linux/gfp.h>
32
33
34/*
35 * GeneSys GL620USB-A (www.genesyslogic.com.tw)
36 *
37 * ... should partially interop with the Win32 driver for this hardware.
38 * The GeneSys docs imply there's some NDIS issue motivating this framing.
39 *
40 * Some info from GeneSys:
41 *  - GL620USB-A is full duplex; GL620USB is only half duplex for bulk.
42 *    (Some cables, like the BAFO-100c, use the half duplex version.)
43 *  - For the full duplex model, the low bit of the version code says
44 *    which side is which ("left/right").
45 *  - For the half duplex type, a control/interrupt handshake settles
46 *    the transfer direction.  (That's disabled here, partially coded.)
47 *    A control URB would block until other side writes an interrupt.
48 *
49 * Original code from Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
50 * and merged into "usbnet" by Stanislav Brabec <utx@penguin.cz>.
51 */
52
53// control msg write command
54#define GENELINK_CONNECT_WRITE			0xF0
55// interrupt pipe index
56#define GENELINK_INTERRUPT_PIPE			0x03
57// interrupt read buffer size
58#define INTERRUPT_BUFSIZE			0x08
59// interrupt pipe interval value
60#define GENELINK_INTERRUPT_INTERVAL		0x10
61// max transmit packet number per transmit
62#define GL_MAX_TRANSMIT_PACKETS			32
63// max packet length
64#define GL_MAX_PACKET_LEN			1514
65// max receive buffer size
66#define GL_RCV_BUF_SIZE		\
67	(((GL_MAX_PACKET_LEN + 4) * GL_MAX_TRANSMIT_PACKETS) + 4)
68
69struct gl_packet {
70	__le32		packet_length;
71	char		packet_data [1];
72};
73
74struct gl_header {
75	__le32			packet_count;
76	struct gl_packet	packets;
77};
78
79static int genelink_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
80{
81	struct gl_header	*header;
82	struct gl_packet	*packet;
83	struct sk_buff		*gl_skb;
84	u32			size;
85	u32			count;
86
87	/* This check is no longer done by usbnet */
88	if (skb->len < dev->net->hard_header_len)
89		return 0;
90
91	header = (struct gl_header *) skb->data;
92
93	// get the packet count of the received skb
94	count = le32_to_cpu(header->packet_count);
95	if (count > GL_MAX_TRANSMIT_PACKETS) {
96		netdev_dbg(dev->net,
97			   "genelink: invalid received packet count %u\n",
98			   count);
99		return 0;
100	}
101
102	// set the current packet pointer to the first packet
103	packet = &header->packets;
104
105	// decrement the length for the packet count size 4 bytes
106	skb_pull(skb, 4);
107
108	while (count > 1) {
109		// get the packet length
110		size = le32_to_cpu(packet->packet_length);
111
112		// this may be a broken packet
113		if (size > GL_MAX_PACKET_LEN) {
114			netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
115				   size);
116			return 0;
117		}
118
119		// allocate the skb for the individual packet
120		gl_skb = alloc_skb(size, GFP_ATOMIC);
121		if (gl_skb) {
122
123			// copy the packet data to the new skb
124			memcpy(skb_put(gl_skb, size),
125					packet->packet_data, size);
126			usbnet_skb_return(dev, gl_skb);
127		}
128
129		// advance to the next packet
130		packet = (struct gl_packet *)&packet->packet_data[size];
131		count--;
132
133		// shift the data pointer to the next gl_packet
134		skb_pull(skb, size + 4);
135	}
136
137	// skip the packet length field 4 bytes
138	skb_pull(skb, 4);
139
140	if (skb->len > GL_MAX_PACKET_LEN) {
141		netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
142			   skb->len);
143		return 0;
144	}
145	return 1;
146}
147
148static struct sk_buff *
149genelink_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
150{
151	int 	padlen;
152	int	length = skb->len;
153	int	headroom = skb_headroom(skb);
154	int	tailroom = skb_tailroom(skb);
155	__le32	*packet_count;
156	__le32	*packet_len;
157
158	// FIXME:  magic numbers, bleech
159	padlen = ((skb->len + (4 + 4*1)) % 64) ? 0 : 1;
160
161	if ((!skb_cloned(skb))
162			&& ((headroom + tailroom) >= (padlen + (4 + 4*1)))) {
163		if ((headroom < (4 + 4*1)) || (tailroom < padlen)) {
164			skb->data = memmove(skb->head + (4 + 4*1),
165					     skb->data, skb->len);
166			skb_set_tail_pointer(skb, skb->len);
167		}
168	} else {
169		struct sk_buff	*skb2;
170		skb2 = skb_copy_expand(skb, (4 + 4*1) , padlen, flags);
171		dev_kfree_skb_any(skb);
172		skb = skb2;
173		if (!skb)
174			return NULL;
175	}
176
177	// attach the packet count to the header
178	packet_count = (__le32 *) skb_push(skb, (4 + 4*1));
179	packet_len = packet_count + 1;
180
181	*packet_count = cpu_to_le32(1);
182	*packet_len = cpu_to_le32(length);
183
184	// add padding byte
185	if ((skb->len % dev->maxpacket) == 0)
186		skb_put(skb, 1);
187
188	return skb;
189}
190
191static int genelink_bind(struct usbnet *dev, struct usb_interface *intf)
192{
193	dev->hard_mtu = GL_RCV_BUF_SIZE;
194	dev->net->hard_header_len += 4;
195	dev->in = usb_rcvbulkpipe(dev->udev, dev->driver_info->in);
196	dev->out = usb_sndbulkpipe(dev->udev, dev->driver_info->out);
197	return 0;
198}
199
200static const struct driver_info	genelink_info = {
201	.description =	"Genesys GeneLink",
202	.flags =	FLAG_POINTTOPOINT | FLAG_FRAMING_GL | FLAG_NO_SETINT,
203	.bind =		genelink_bind,
204	.rx_fixup =	genelink_rx_fixup,
205	.tx_fixup =	genelink_tx_fixup,
206
207	.in = 1, .out = 2,
208
209#ifdef	GENELINK_ACK
210	.check_connect =genelink_check_connect,
211#endif
212};
213
214static const struct usb_device_id	products [] = {
215
216{
217	USB_DEVICE(0x05e3, 0x0502),	// GL620USB-A
218	.driver_info =	(unsigned long) &genelink_info,
219},
220	/* NOT: USB_DEVICE(0x05e3, 0x0501),	// GL620USB
221	 * that's half duplex, not currently supported
222	 */
223	{ },		// END
224};
225MODULE_DEVICE_TABLE(usb, products);
226
227static struct usb_driver gl620a_driver = {
228	.name =		"gl620a",
229	.id_table =	products,
230	.probe =	usbnet_probe,
231	.disconnect =	usbnet_disconnect,
232	.suspend =	usbnet_suspend,
233	.resume =	usbnet_resume,
234	.disable_hub_initiated_lpm = 1,
235};
236
237module_usb_driver(gl620a_driver);
238
239MODULE_AUTHOR("Jiun-Jie Huang");
240MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
241MODULE_LICENSE("GPL");
242
243