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, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19 */
20
21// #define	DEBUG			// error path messages, extra info
22// #define	VERBOSE			// more; success messages
23
24#include <linux/module.h>
25#include <linux/init.h>
26#include <linux/netdevice.h>
27#include <linux/etherdevice.h>
28#include <linux/ethtool.h>
29#include <linux/workqueue.h>
30#include <linux/mii.h>
31#include <linux/usb.h>
32#include <linux/usb/usbnet.h>
33#include <linux/gfp.h>
34
35
36/*
37 * GeneSys GL620USB-A (www.genesyslogic.com.tw)
38 *
39 * ... should partially interop with the Win32 driver for this hardware.
40 * The GeneSys docs imply there's some NDIS issue motivating this framing.
41 *
42 * Some info from GeneSys:
43 *  - GL620USB-A is full duplex; GL620USB is only half duplex for bulk.
44 *    (Some cables, like the BAFO-100c, use the half duplex version.)
45 *  - For the full duplex model, the low bit of the version code says
46 *    which side is which ("left/right").
47 *  - For the half duplex type, a control/interrupt handshake settles
48 *    the transfer direction.  (That's disabled here, partially coded.)
49 *    A control URB would block until other side writes an interrupt.
50 *
51 * Original code from Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
52 * and merged into "usbnet" by Stanislav Brabec <utx@penguin.cz>.
53 */
54
55// control msg write command
56#define GENELINK_CONNECT_WRITE			0xF0
57// interrupt pipe index
58#define GENELINK_INTERRUPT_PIPE			0x03
59// interrupt read buffer size
60#define INTERRUPT_BUFSIZE			0x08
61// interrupt pipe interval value
62#define GENELINK_INTERRUPT_INTERVAL		0x10
63// max transmit packet number per transmit
64#define GL_MAX_TRANSMIT_PACKETS			32
65// max packet length
66#define GL_MAX_PACKET_LEN			1514
67// max receive buffer size
68#define GL_RCV_BUF_SIZE		\
69	(((GL_MAX_PACKET_LEN + 4) * GL_MAX_TRANSMIT_PACKETS) + 4)
70
71struct gl_packet {
72	__le32		packet_length;
73	char		packet_data [1];
74};
75
76struct gl_header {
77	__le32			packet_count;
78	struct gl_packet	packets;
79};
80
81static int genelink_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
82{
83	struct gl_header	*header;
84	struct gl_packet	*packet;
85	struct sk_buff		*gl_skb;
86	u32			size;
87	u32			count;
88
89	header = (struct gl_header *) skb->data;
90
91	// get the packet count of the received skb
92	count = le32_to_cpu(header->packet_count);
93	if (count > GL_MAX_TRANSMIT_PACKETS) {
94		dbg("genelink: invalid received packet count %u", count);
95		return 0;
96	}
97
98	// set the current packet pointer to the first packet
99	packet = &header->packets;
100
101	// decrement the length for the packet count size 4 bytes
102	skb_pull(skb, 4);
103
104	while (count > 1) {
105		// get the packet length
106		size = le32_to_cpu(packet->packet_length);
107
108		// this may be a broken packet
109		if (size > GL_MAX_PACKET_LEN) {
110			dbg("genelink: invalid rx length %d", size);
111			return 0;
112		}
113
114		// allocate the skb for the individual packet
115		gl_skb = alloc_skb(size, GFP_ATOMIC);
116		if (gl_skb) {
117
118			// copy the packet data to the new skb
119			memcpy(skb_put(gl_skb, size),
120					packet->packet_data, size);
121			usbnet_skb_return(dev, gl_skb);
122		}
123
124		// advance to the next packet
125		packet = (struct gl_packet *)&packet->packet_data[size];
126		count--;
127
128		// shift the data pointer to the next gl_packet
129		skb_pull(skb, size + 4);
130	}
131
132	// skip the packet length field 4 bytes
133	skb_pull(skb, 4);
134
135	if (skb->len > GL_MAX_PACKET_LEN) {
136		dbg("genelink: invalid rx length %d", skb->len);
137		return 0;
138	}
139	return 1;
140}
141
142static struct sk_buff *
143genelink_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
144{
145	int 	padlen;
146	int	length = skb->len;
147	int	headroom = skb_headroom(skb);
148	int	tailroom = skb_tailroom(skb);
149	__le32	*packet_count;
150	__le32	*packet_len;
151
152	padlen = ((skb->len + (4 + 4*1)) % 64) ? 0 : 1;
153
154	if ((!skb_cloned(skb))
155			&& ((headroom + tailroom) >= (padlen + (4 + 4*1)))) {
156		if ((headroom < (4 + 4*1)) || (tailroom < padlen)) {
157			skb->data = memmove(skb->head + (4 + 4*1),
158					     skb->data, skb->len);
159			skb_set_tail_pointer(skb, skb->len);
160		}
161	} else {
162		struct sk_buff	*skb2;
163		skb2 = skb_copy_expand(skb, (4 + 4*1) , padlen, flags);
164		dev_kfree_skb_any(skb);
165		skb = skb2;
166		if (!skb)
167			return NULL;
168	}
169
170	// attach the packet count to the header
171	packet_count = (__le32 *) skb_push(skb, (4 + 4*1));
172	packet_len = packet_count + 1;
173
174	*packet_count = cpu_to_le32(1);
175	*packet_len = cpu_to_le32(length);
176
177	// add padding byte
178	if ((skb->len % dev->maxpacket) == 0)
179		skb_put(skb, 1);
180
181	return skb;
182}
183
184static int genelink_bind(struct usbnet *dev, struct usb_interface *intf)
185{
186	dev->hard_mtu = GL_RCV_BUF_SIZE;
187	dev->net->hard_header_len += 4;
188	dev->in = usb_rcvbulkpipe(dev->udev, dev->driver_info->in);
189	dev->out = usb_sndbulkpipe(dev->udev, dev->driver_info->out);
190	return 0;
191}
192
193static const struct driver_info	genelink_info = {
194	.description =	"Genesys GeneLink",
195	.flags =	FLAG_FRAMING_GL | FLAG_NO_SETINT,
196	.bind =		genelink_bind,
197	.rx_fixup =	genelink_rx_fixup,
198	.tx_fixup =	genelink_tx_fixup,
199
200	.in = 1, .out = 2,
201
202#ifdef	GENELINK_ACK
203	.check_connect =genelink_check_connect,
204#endif
205};
206
207static const struct usb_device_id	products [] = {
208
209{
210	USB_DEVICE(0x05e3, 0x0502),	// GL620USB-A
211	.driver_info =	(unsigned long) &genelink_info,
212},
213	/* NOT: USB_DEVICE(0x05e3, 0x0501),	// GL620USB
214	 * that's half duplex, not currently supported
215	 */
216	{ },		// END
217};
218MODULE_DEVICE_TABLE(usb, products);
219
220static struct usb_driver gl620a_driver = {
221	.name =		"gl620a",
222	.id_table =	products,
223	.probe =	usbnet_probe,
224	.disconnect =	usbnet_disconnect,
225	.suspend =	usbnet_suspend,
226	.resume =	usbnet_resume,
227};
228
229static int __init usbnet_init(void)
230{
231 	return usb_register(&gl620a_driver);
232}
233module_init(usbnet_init);
234
235static void __exit usbnet_exit(void)
236{
237 	usb_deregister(&gl620a_driver);
238}
239module_exit(usbnet_exit);
240
241MODULE_AUTHOR("Jiun-Jie Huang");
242MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
243MODULE_LICENSE("GPL");
244