plusb.c

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/*
 * PL-2301/2302 USB host-to-host link cables
 * Copyright (C) 2000-2005 by David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

// #define  DEBUG           // error path messages, extra info
// #define  VERBOSE         // more; success messages

#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/workqueue.h>
#include <linux/mii.h>
#include <linux/usb.h>
#include <linux/usb/usbnet.h>


/*
 * Prolific PL-2301/PL-2302 driver ... http://www.prolific.com.tw/ 
 *
 * The protocol and handshaking used here should be bug-compatible
 * with the Linux 2.2 "plusb" driver, by Deti Fliegl.
 *
 * HEADS UP:  this handshaking isn't all that robust.  This driver
 * gets confused easily if you unplug one end of the cable then
 * try to connect it again; you'll need to restart both ends. The
 * "naplink" software (used by some PlayStation/2 deveopers) does
 * the handshaking much better!   Also, sometimes this hardware
 * seems to get wedged under load.  Prolific docs are weak, and
 * don't identify differences between PL2301 and PL2302, much less
 * anything to explain the different PL2302 versions observed.
 *
 * NOTE:  pl2501 has several modes, including pl2301 and pl2302
 * compatibility.   Some docs suggest the difference between 2301
 * and 2302 is only to make MS-Windows use a different driver...
 *
 * pl25a1 glue based on patch from Tony Gibbs.  Prolific "docs" on
 * this chip are as usual incomplete about what control messages
 * are supported.
 */

/*
 * Bits 0-4 can be used for software handshaking; they're set from
 * one end, cleared from the other, "read" with the interrupt byte.
 */
#define PL_S_EN     (1<<7)      /* (feature only) suspend enable */
/* reserved bit -- rx ready (6) ? */
#define PL_TX_READY (1<<5)      /* (interrupt only) transmit ready */
#define PL_RESET_OUT    (1<<4)      /* reset output pipe */
#define PL_RESET_IN (1<<3)      /* reset input pipe */
#define PL_TX_C     (1<<2)      /* transmission complete */
#define PL_TX_REQ   (1<<1)      /* transmission received */
#define PL_PEER_E   (1<<0)      /* peer exists */

static inline int
pl_vendor_req(struct usbnet *dev, u8 req, u8 val, u8 index)
{
    return usb_control_msg(dev->udev,
        usb_rcvctrlpipe(dev->udev, 0),
        req,
        USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
        val, index,
        NULL, 0,
        USB_CTRL_GET_TIMEOUT);
}

static inline int
pl_clear_QuickLink_features(struct usbnet *dev, int val)
{
    return pl_vendor_req(dev, 1, (u8) val, 0);
}

static inline int
pl_set_QuickLink_features(struct usbnet *dev, int val)
{
    return pl_vendor_req(dev, 3, (u8) val, 0);
}

static int pl_reset(struct usbnet *dev)
{
    int status;

    /* some units seem to need this reset, others reject it utterly.
     * FIXME be more like "naplink" or windows drivers.
     */
    status = pl_set_QuickLink_features(dev,
        PL_S_EN|PL_RESET_OUT|PL_RESET_IN|PL_PEER_E);
    if (status != 0 && netif_msg_probe(dev))
        netif_dbg(dev, link, dev->net, "pl_reset --> %d\n", status);
    return 0;
}

static const struct driver_info prolific_info = {
    .description =  "Prolific PL-2301/PL-2302/PL-25A1",
    .flags =    FLAG_POINTTOPOINT | FLAG_NO_SETINT,
        /* some PL-2302 versions seem to fail usb_set_interface() */
    .reset =    pl_reset,
};


/*-------------------------------------------------------------------------*/

/*
 * Proilific's name won't normally be on the cables, and
 * may not be on the device.
 */

static const struct usb_device_id   products [] = {

/* full speed cables */
{
    USB_DEVICE(0x067b, 0x0000), // PL-2301
    .driver_info =  (unsigned long) &prolific_info,
}, {
    USB_DEVICE(0x067b, 0x0001), // PL-2302
    .driver_info =  (unsigned long) &prolific_info,
},

/* high speed cables */
{
    USB_DEVICE(0x067b, 0x25a1),     /* PL-25A1, no eeprom */
    .driver_info =  (unsigned long) &prolific_info,
}, {
    USB_DEVICE(0x050d, 0x258a),     /* Belkin F5U258/F5U279 (PL-25A1) */
    .driver_info =  (unsigned long) &prolific_info,
},

    { },        // END
};
MODULE_DEVICE_TABLE(usb, products);

static struct usb_driver plusb_driver = {
    .name =     "plusb",
    .id_table = products,
    .probe =    usbnet_probe,
    .disconnect =   usbnet_disconnect,
    .suspend =  usbnet_suspend,
    .resume =   usbnet_resume,
    .disable_hub_initiated_lpm = 1,
};

module_usb_driver(plusb_driver);

MODULE_AUTHOR("David Brownell");
MODULE_DESCRIPTION("Prolific PL-2301/2302/25A1 USB Host to Host Link Driver");
MODULE_LICENSE("GPL");