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/drivers/net/usb/gl620a.c

http://github.com/mirrors/linux
C | 229 lines | 141 code | 38 blank | 50 comment | 14 complexity | 0f950f2e712b58474c43b03c51a09214 MD5 | raw file
  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
 57struct gl_packet {
 58	__le32		packet_length;
 59	char		packet_data [1];
 60};
 61
 62struct gl_header {
 63	__le32			packet_count;
 64	struct gl_packet	packets;
 65};
 66
 67static 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
135static struct sk_buff *
136genelink_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
178static 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
187static 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
201static 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};
212MODULE_DEVICE_TABLE(usb, products);
213
214static 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
224module_usb_driver(gl620a_driver);
225
226MODULE_AUTHOR("Jiun-Jie Huang");
227MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
228MODULE_LICENSE("GPL");
229