/***************************************************************************/
/*! \file dumm_accel_backend.c Dummy accelerated plugin module

Copyright 2006 Solarflare Communications Inc,
               9501 Jeronimo Road, Suite 250,
               Irvine, CA 92618, USA

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License version 2 as published by the Free
Software Foundation, incorporated herein by reference.

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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

*/
/***************************************************************************/

static struct netback_accel_hooks accel_hooks = {
        &netback_accel_probe,
        &netback_accel_remove
};

static const char *frontend_name = "dummynetaccel";

static int netback_accel_init(void)
{
        /* Initialise the rest of the module... */

        /* Tell the netback that we're here */
        netback_connect_accelerator(0, frontend_name, &accel_hooks);
}
module_init(netback_accel_init);


static void __exit netback_accel_exit(void)
{
        netback_disconnect_accelerator(0, frontend_name);

        /* ...and take down the rest of the module */
}
module_exit(netback_accel_exit);




int netback_accel_probe(struct xenbus_device *dev)
{
        struct backend_info *binfo;

        /* Setup per-device internal state */

        /* Store internal state for future access */
        binfo = (struct backend_info *) dev->dev.driver_data;
        binfo->netback_accel_priv = my_internal_state;

        /* Setup watch on accel-state, so we know when frontend
           acceleration plugin is loaded */
        setup_domu_accel_watch(dev, my_internal_state);
}


int netback_accel_remove(struct xenbus_device *dev)
{
        /* Cleanup as the device is going away */
}


void netback_accel_frontend_changed(struct xenbus_device *dev,
                                    XenbusState frontend_state)
{
        switch(frontend_state) {
        case XenbusStateConnected:
                /* Frontend has loaded and is ready to go */
                /* Initialise ourselves */
                setup_accel_backend();
                netback_accel_update_state(dev, XenbusStateConnected);
        }
}


void netback_accel_update_state(struct xenbus_device *dev, int state)
{
        struct xenbus_transaction tr;
        int err;

        if(xenbus_exists(XBT_NIL, dev->nodename, "")) {
        again:
                err = xenbus_transaction_start(&tr);
                if (err == 0)
                        err = xenbus_printf(tr, dev->nodename, "accelstate", "%d", 
                                            state);
                if (err != 0)
                        xenbus_transaction_end(tr, 1);
                else {
                        err = xenbus_transaction_end(tr, 0);
                        if(err == -EAGAIN)
                                goto again;
                }
        }
}