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, 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
  34
  35 /*
  36  * GeneSys GL620USB-A (www.genesyslogic.com.tw)
  37  *
  38  * ... should partially interop with the Win32 driver for this hardware.
  39  * The GeneSys docs imply there's some NDIS issue motivating this framing.
  40  *
  41  * Some info from GeneSys:
  42  *  - GL620USB-A is full duplex; GL620USB is only half duplex for bulk.
  43  *    (Some cables, like the BAFO-100c, use the half duplex version.)
  44  *  - For the full duplex model, the low bit of the version code says
  45  *    which side is which ("left/right").
  46  *  - For the half duplex type, a control/interrupt handshake settles
  47  *    the transfer direction.  (That's disabled here, partially coded.)
  48  *    A control URB would block until other side writes an interrupt.
  49  *
  50  * Original code from Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
  51  * and merged into "usbnet" by Stanislav Brabec <utx@penguin.cz>.
  52  */
  53
  54 // control msg write command
  55 #define GENELINK_CONNECT_WRITE                  0xF0
  56 // interrupt pipe index
  57 #define GENELINK_INTERRUPT_PIPE                 0x03
  58 // interrupt read buffer size
  59 #define INTERRUPT_BUFSIZE                       0x08
  60 // interrupt pipe interval value
  61 #define GENELINK_INTERRUPT_INTERVAL             0x10
  62 // max transmit packet number per transmit
  63 #define GL_MAX_TRANSMIT_PACKETS                 32
  64 // max packet length
  65 #define GL_MAX_PACKET_LEN                       1514
  66 // max receive buffer size
  67 #define GL_RCV_BUF_SIZE         \
  68         (((GL_MAX_PACKET_LEN + 4) * GL_MAX_TRANSMIT_PACKETS) + 4)
  69
  70 struct gl_packet {
  71         __le32          packet_length;
  72         char            packet_data [1];
  73 };
  74
  75 struct gl_header {
  76         __le32                  packet_count;
  77         struct gl_packet        packets;
  78 };
  79
  80 static int genelink_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
  81 {
  82         struct gl_header        *header;
  83         struct gl_packet        *packet;
  84         struct sk_buff          *gl_skb;
  85         u32                     size;
  86         u32                     count;
  87
  88         header = (struct gl_header *) skb->data;
  89
  90         // get the packet count of the received skb
  91         count = le32_to_cpu(header->packet_count);
  92         if (count > GL_MAX_TRANSMIT_PACKETS) {
  93                 dbg("genelink: invalid received packet count %u", count);
  94                 return 0;
  95         }
  96
  97         // set the current packet pointer to the first packet
  98         packet = &header->packets;
  99
 100         // decrement the length for the packet count size 4 bytes
 101         skb_pull(skb, 4);
 102
 103         while (count > 1) {
 104                 // get the packet length
 105                 size = le32_to_cpu(packet->packet_length);
 106
 107                 // this may be a broken packet
 108                 if (size > GL_MAX_PACKET_LEN) {
 109                         dbg("genelink: invalid rx length %d", size);
 110                         return 0;
 111                 }
 112
 113                 // allocate the skb for the individual packet
 114                 gl_skb = alloc_skb(size, GFP_ATOMIC);
 115                 if (gl_skb) {
 116
 117                         // copy the packet data to the new skb
 118                         memcpy(skb_put(gl_skb, size),
 119                                         packet->packet_data, size);
 120                         usbnet_skb_return(dev, gl_skb);
 121                 }
 122
 123                 // advance to the next packet
 124                 packet = (struct gl_packet *)&packet->packet_data[size];
 125                 count--;
 126
 127                 // shift the data pointer to the next gl_packet
 128                 skb_pull(skb, size + 4);
 129         }
 130
 131         // skip the packet length field 4 bytes
 132         skb_pull(skb, 4);
 133
 134         if (skb->len > GL_MAX_PACKET_LEN) {
 135                 dbg("genelink: invalid rx length %d", skb->len);
 136                 return 0;
 137         }
 138         return 1;
 139 }
 140
 141 static struct sk_buff *
 142 genelink_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 143 {
 144         int     padlen;
 145         int     length = skb->len;
 146         int     headroom = skb_headroom(skb);
 147         int     tailroom = skb_tailroom(skb);
 148         __le32  *packet_count;
 149         __le32  *packet_len;
 150
 151         // FIXME:  magic numbers, bleech
 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
 184 static 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
 193 static 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
 207 static 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 };
 218 MODULE_DEVICE_TABLE(usb, products);
 219
 220 static 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
 229 static int __init usbnet_init(void)
 230 {
 231         return usb_register(&gl620a_driver);
 232 }
 233 module_init(usbnet_init);
 234
 235 static void __exit usbnet_exit(void)
 236 {
 237         usb_deregister(&gl620a_driver);
 238 }
 239 module_exit(usbnet_exit);
 240
 241 MODULE_AUTHOR("Jiun-Jie Huang");
 242 MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
 243 MODULE_LICENSE("GPL");
 244