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 #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                 dbg("genelink: invalid received packet count %u", count);
  95                 return 0;
  96         }
  97
  98         // set the current packet pointer to the first packet
  99         packet = &header->packets;
 100
 101         // decrement the length for the packet count size 4 bytes
 102         skb_pull(skb, 4);
 103
 104         while (count > 1) {
 105                 // get the packet length
 106                 size = le32_to_cpu(packet->packet_length);
 107
 108                 // this may be a broken packet
 109                 if (size > GL_MAX_PACKET_LEN) {
 110                         dbg("genelink: invalid rx length %d", size);
 111                         return 0;
 112                 }
 113
 114                 // allocate the skb for the individual packet
 115                 gl_skb = alloc_skb(size, GFP_ATOMIC);
 116                 if (gl_skb) {
 117
 118                         // copy the packet data to the new skb
 119                         memcpy(skb_put(gl_skb, size),
 120                                         packet->packet_data, size);
 121                         usbnet_skb_return(dev, gl_skb);
 122                 }
 123
 124                 // advance to the next packet
 125                 packet = (struct gl_packet *)&packet->packet_data[size];
 126                 count--;
 127
 128                 // shift the data pointer to the next gl_packet
 129                 skb_pull(skb, size + 4);
 130         }
 131
 132         // skip the packet length field 4 bytes
 133         skb_pull(skb, 4);
 134
 135         if (skb->len > GL_MAX_PACKET_LEN) {
 136                 dbg("genelink: invalid rx length %d", skb->len);
 137                 return 0;
 138         }
 139         return 1;
 140 }
 141
 142 static struct sk_buff *
 143 genelink_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 144 {
 145         int     padlen;
 146         int     length = skb->len;
 147         int     headroom = skb_headroom(skb);
 148         int     tailroom = skb_tailroom(skb);
 149         __le32  *packet_count;
 150         __le32  *packet_len;
 151
 152         // FIXME:  magic numbers, bleech
 153         padlen = ((skb->len + (4 + 4*1)) % 64) ? 0 : 1;
 154
 155         if ((!skb_cloned(skb))
 156                         && ((headroom + tailroom) >= (padlen + (4 + 4*1)))) {
 157                 if ((headroom < (4 + 4*1)) || (tailroom < padlen)) {
 158                         skb->data = memmove(skb->head + (4 + 4*1),
 159                                              skb->data, skb->len);
 160                         skb_set_tail_pointer(skb, skb->len);
 161                 }
 162         } else {
 163                 struct sk_buff  *skb2;
 164                 skb2 = skb_copy_expand(skb, (4 + 4*1) , padlen, flags);
 165                 dev_kfree_skb_any(skb);
 166                 skb = skb2;
 167                 if (!skb)
 168                         return NULL;
 169         }
 170
 171         // attach the packet count to the header
 172         packet_count = (__le32 *) skb_push(skb, (4 + 4*1));
 173         packet_len = packet_count + 1;
 174
 175         *packet_count = cpu_to_le32(1);
 176         *packet_len = cpu_to_le32(length);
 177
 178         // add padding byte
 179         if ((skb->len % dev->maxpacket) == 0)
 180                 skb_put(skb, 1);
 181
 182         return skb;
 183 }
 184
 185 static int genelink_bind(struct usbnet *dev, struct usb_interface *intf)
 186 {
 187         dev->hard_mtu = GL_RCV_BUF_SIZE;
 188         dev->net->hard_header_len += 4;
 189         dev->in = usb_rcvbulkpipe(dev->udev, dev->driver_info->in);
 190         dev->out = usb_sndbulkpipe(dev->udev, dev->driver_info->out);
 191         return 0;
 192 }
 193
 194 static const struct driver_info genelink_info = {
 195         .description =  "Genesys GeneLink",
 196         .flags =        FLAG_POINTTOPOINT | FLAG_FRAMING_GL | FLAG_NO_SETINT,
 197         .bind =         genelink_bind,
 198         .rx_fixup =     genelink_rx_fixup,
 199         .tx_fixup =     genelink_tx_fixup,
 200
 201         .in = 1, .out = 2,
 202
 203 #ifdef  GENELINK_ACK
 204         .check_connect =genelink_check_connect,
 205 #endif
 206 };
 207
 208 static const struct usb_device_id       products [] = {
 209
 210 {
 211         USB_DEVICE(0x05e3, 0x0502),     // GL620USB-A
 212         .driver_info =  (unsigned long) &genelink_info,
 213 },
 214         /* NOT: USB_DEVICE(0x05e3, 0x0501),     // GL620USB
 215          * that's half duplex, not currently supported
 216          */
 217         { },            // END
 218 };
 219 MODULE_DEVICE_TABLE(usb, products);
 220
 221 static struct usb_driver gl620a_driver = {
 222         .name =         "gl620a",
 223         .id_table =     products,
 224         .probe =        usbnet_probe,
 225         .disconnect =   usbnet_disconnect,
 226         .suspend =      usbnet_suspend,
 227         .resume =       usbnet_resume,
 228 };
 229
 230 static int __init usbnet_init(void)
 231 {
 232         return usb_register(&gl620a_driver);
 233 }
 234 module_init(usbnet_init);
 235
 236 static void __exit usbnet_exit(void)
 237 {
 238         usb_deregister(&gl620a_driver);
 239 }
 240 module_exit(usbnet_exit);
 241
 242 MODULE_AUTHOR("Jiun-Jie Huang");
 243 MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
 244 MODULE_LICENSE("GPL");
 245