/*
 *  Copyright (c) 2000-2001 Vojtech Pavlik <vojtech@ucw.cz>
 *  Copyright (c) 2001, 2007 Johann Deneux <johann.deneux@gmail.com>
 *
 *  USB/RS232 I-Force joysticks and wheels.
 */

/*
 * 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
 *
 * Should you need to contact me, the author, you can do so either by
 * e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
 * Vojtech Pavlik, Simunkova 1594, Prague 8, 182 00 Czech Republic
 */

#include "iforce.h"

void iforce_serial_xmit(struct iforce *iforce)
{
        unsigned char cs;
        int i;
        unsigned long flags;

        if (test_and_set_bit(IFORCE_XMIT_RUNNING, iforce->xmit_flags)) {
                set_bit(IFORCE_XMIT_AGAIN, iforce->xmit_flags);
                return;
        }

        spin_lock_irqsave(&iforce->xmit_lock, flags);

again:
        if (iforce->xmit.head == iforce->xmit.tail) {
                clear_bit(IFORCE_XMIT_RUNNING, iforce->xmit_flags);
                spin_unlock_irqrestore(&iforce->xmit_lock, flags);
                return;
        }

        cs = 0x2b;

        serio_write(iforce->serio, 0x2b);

        serio_write(iforce->serio, iforce->xmit.buf[iforce->xmit.tail]);
        cs ^= iforce->xmit.buf[iforce->xmit.tail];
        XMIT_INC(iforce->xmit.tail, 1);

        for (i=iforce->xmit.buf[iforce->xmit.tail]; i >= 0; --i) {
                serio_write(iforce->serio, iforce->xmit.buf[iforce->xmit.tail]);
                cs ^= iforce->xmit.buf[iforce->xmit.tail];
                XMIT_INC(iforce->xmit.tail, 1);
        }

        serio_write(iforce->serio, cs);

        if (test_and_clear_bit(IFORCE_XMIT_AGAIN, iforce->xmit_flags))
                goto again;

        clear_bit(IFORCE_XMIT_RUNNING, iforce->xmit_flags);

        spin_unlock_irqrestore(&iforce->xmit_lock, flags);
}

static void iforce_serio_write_wakeup(struct serio *serio)
{
        struct iforce *iforce = serio_get_drvdata(serio);

        iforce_serial_xmit(iforce);
}

static irqreturn_t iforce_serio_irq(struct serio *serio,
                unsigned char data, unsigned int flags)
{
        struct iforce *iforce = serio_get_drvdata(serio);

        if (!iforce->pkt) {
                if (data == 0x2b)
                        iforce->pkt = 1;
                goto out;
        }

        if (!iforce->id) {
                if (data > 3 && data != 0xff)
                        iforce->pkt = 0;
                else
                        iforce->id = data;
                goto out;
        }

        if (!iforce->len) {
                if (data > IFORCE_MAX_LENGTH) {
                        iforce->pkt = 0;
                        iforce->id = 0;
                } else {
                        iforce->len = data;
                }
                goto out;
        }

        if (iforce->idx < iforce->len) {
                iforce->csum += iforce->data[iforce->idx++] = data;
                goto out;
        }

        if (iforce->idx == iforce->len) {
                iforce_process_packet(iforce, (iforce->id << 8) | iforce->idx, iforce->data);
                iforce->pkt = 0;
                iforce->id  = 0;
                iforce->len = 0;
                iforce->idx = 0;
                iforce->csum = 0;
        }
out:
        return IRQ_HANDLED;
}

static int iforce_serio_connect(struct serio *serio, struct serio_driver *drv)
{
        struct iforce *iforce;
        int err;

        iforce = kzalloc(sizeof(struct iforce), GFP_KERNEL);
        if (!iforce)
                return -ENOMEM;

        iforce->bus = IFORCE_232;
        iforce->serio = serio;

        serio_set_drvdata(serio, iforce);

        err = serio_open(serio, drv);
        if (err)
                goto fail1;

        err = iforce_init_device(iforce);
        if (err)
                goto fail2;

        return 0;

 fail2: serio_close(serio);
 fail1: serio_set_drvdata(serio, NULL);
        kfree(iforce);
        return err;
}

static void iforce_serio_disconnect(struct serio *serio)
{
        struct iforce *iforce = serio_get_drvdata(serio);

        input_unregister_device(iforce->dev);
        serio_close(serio);
        serio_set_drvdata(serio, NULL);
        kfree(iforce);
}

static struct serio_device_id iforce_serio_ids[] = {
        {
                .type   = SERIO_RS232,
                .proto  = SERIO_IFORCE,
                .id     = SERIO_ANY,
                .extra  = SERIO_ANY,
        },
        { 0 }
};

MODULE_DEVICE_TABLE(serio, iforce_serio_ids);

struct serio_driver iforce_serio_drv = {
        .driver         = {
                .name   = "iforce",
        },
        .description    = "RS232 I-Force joysticks and wheels driver",
        .id_table       = iforce_serio_ids,
        .write_wakeup   = iforce_serio_write_wakeup,
        .interrupt      = iforce_serio_irq,
        .connect        = iforce_serio_connect,
        .disconnect     = iforce_serio_disconnect,
};