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