xref: /openbmc/linux/drivers/net/usb/gl620a.c (revision 12eb4683)
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 
71 struct gl_packet {
72 	__le32		packet_length;
73 	char		packet_data [1];
74 };
75 
76 struct gl_header {
77 	__le32			packet_count;
78 	struct gl_packet	packets;
79 };
80 
81 static 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 		netdev_dbg(dev->net,
95 			   "genelink: invalid received packet count %u\n",
96 			   count);
97 		return 0;
98 	}
99 
100 	// set the current packet pointer to the first packet
101 	packet = &header->packets;
102 
103 	// decrement the length for the packet count size 4 bytes
104 	skb_pull(skb, 4);
105 
106 	while (count > 1) {
107 		// get the packet length
108 		size = le32_to_cpu(packet->packet_length);
109 
110 		// this may be a broken packet
111 		if (size > GL_MAX_PACKET_LEN) {
112 			netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
113 				   size);
114 			return 0;
115 		}
116 
117 		// allocate the skb for the individual packet
118 		gl_skb = alloc_skb(size, GFP_ATOMIC);
119 		if (gl_skb) {
120 
121 			// copy the packet data to the new skb
122 			memcpy(skb_put(gl_skb, size),
123 					packet->packet_data, size);
124 			usbnet_skb_return(dev, gl_skb);
125 		}
126 
127 		// advance to the next packet
128 		packet = (struct gl_packet *)&packet->packet_data[size];
129 		count--;
130 
131 		// shift the data pointer to the next gl_packet
132 		skb_pull(skb, size + 4);
133 	}
134 
135 	// skip the packet length field 4 bytes
136 	skb_pull(skb, 4);
137 
138 	if (skb->len > GL_MAX_PACKET_LEN) {
139 		netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
140 			   skb->len);
141 		return 0;
142 	}
143 	return 1;
144 }
145 
146 static struct sk_buff *
147 genelink_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
148 {
149 	int 	padlen;
150 	int	length = skb->len;
151 	int	headroom = skb_headroom(skb);
152 	int	tailroom = skb_tailroom(skb);
153 	__le32	*packet_count;
154 	__le32	*packet_len;
155 
156 	// FIXME:  magic numbers, bleech
157 	padlen = ((skb->len + (4 + 4*1)) % 64) ? 0 : 1;
158 
159 	if ((!skb_cloned(skb))
160 			&& ((headroom + tailroom) >= (padlen + (4 + 4*1)))) {
161 		if ((headroom < (4 + 4*1)) || (tailroom < padlen)) {
162 			skb->data = memmove(skb->head + (4 + 4*1),
163 					     skb->data, skb->len);
164 			skb_set_tail_pointer(skb, skb->len);
165 		}
166 	} else {
167 		struct sk_buff	*skb2;
168 		skb2 = skb_copy_expand(skb, (4 + 4*1) , padlen, flags);
169 		dev_kfree_skb_any(skb);
170 		skb = skb2;
171 		if (!skb)
172 			return NULL;
173 	}
174 
175 	// attach the packet count to the header
176 	packet_count = (__le32 *) skb_push(skb, (4 + 4*1));
177 	packet_len = packet_count + 1;
178 
179 	*packet_count = cpu_to_le32(1);
180 	*packet_len = cpu_to_le32(length);
181 
182 	// add padding byte
183 	if ((skb->len % dev->maxpacket) == 0)
184 		skb_put(skb, 1);
185 
186 	return skb;
187 }
188 
189 static int genelink_bind(struct usbnet *dev, struct usb_interface *intf)
190 {
191 	dev->hard_mtu = GL_RCV_BUF_SIZE;
192 	dev->net->hard_header_len += 4;
193 	dev->in = usb_rcvbulkpipe(dev->udev, dev->driver_info->in);
194 	dev->out = usb_sndbulkpipe(dev->udev, dev->driver_info->out);
195 	return 0;
196 }
197 
198 static const struct driver_info	genelink_info = {
199 	.description =	"Genesys GeneLink",
200 	.flags =	FLAG_POINTTOPOINT | FLAG_FRAMING_GL | FLAG_NO_SETINT,
201 	.bind =		genelink_bind,
202 	.rx_fixup =	genelink_rx_fixup,
203 	.tx_fixup =	genelink_tx_fixup,
204 
205 	.in = 1, .out = 2,
206 
207 #ifdef	GENELINK_ACK
208 	.check_connect =genelink_check_connect,
209 #endif
210 };
211 
212 static const struct usb_device_id	products [] = {
213 
214 {
215 	USB_DEVICE(0x05e3, 0x0502),	// GL620USB-A
216 	.driver_info =	(unsigned long) &genelink_info,
217 },
218 	/* NOT: USB_DEVICE(0x05e3, 0x0501),	// GL620USB
219 	 * that's half duplex, not currently supported
220 	 */
221 	{ },		// END
222 };
223 MODULE_DEVICE_TABLE(usb, products);
224 
225 static struct usb_driver gl620a_driver = {
226 	.name =		"gl620a",
227 	.id_table =	products,
228 	.probe =	usbnet_probe,
229 	.disconnect =	usbnet_disconnect,
230 	.suspend =	usbnet_suspend,
231 	.resume =	usbnet_resume,
232 	.disable_hub_initiated_lpm = 1,
233 };
234 
235 module_usb_driver(gl620a_driver);
236 
237 MODULE_AUTHOR("Jiun-Jie Huang");
238 MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
239 MODULE_LICENSE("GPL");
240 
241