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Linux/drivers/net/usb/gl620a.c

  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 
 69 struct gl_packet {
 70         __le32          packet_length;
 71         char            packet_data [1];
 72 };
 73 
 74 struct gl_header {
 75         __le32                  packet_count;
 76         struct gl_packet        packets;
 77 };
 78 
 79 static 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 
148 static struct sk_buff *
149 genelink_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 
191 static 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 
200 static 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 
214 static 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 };
225 MODULE_DEVICE_TABLE(usb, products);
226 
227 static 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 
237 module_usb_driver(gl620a_driver);
238 
239 MODULE_AUTHOR("Jiun-Jie Huang");
240 MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
241 MODULE_LICENSE("GPL");
242 
243 

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