linux/drivers/net/usb/gl620a.c
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   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
  71struct gl_packet {
  72        __le32          packet_length;
  73        char            packet_data [1];
  74};
  75
  76struct gl_header {
  77        __le32                  packet_count;
  78        struct gl_packet        packets;
  79};
  80
  81static 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
 142static struct sk_buff *
 143genelink_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
 185static 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
 194static 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
 208static 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};
 219MODULE_DEVICE_TABLE(usb, products);
 220
 221static 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        .disable_hub_initiated_lpm = 1,
 229};
 230
 231module_usb_driver(gl620a_driver);
 232
 233MODULE_AUTHOR("Jiun-Jie Huang");
 234MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
 235MODULE_LICENSE("GPL");
 236
 237