// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) 1999-2001 Vojtech Pavlik
 */

/*
 * Creative Labs Blaster GamePad Cobra driver for Linux
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/gameport.h>
#include <linux/input.h>
#include <linux/jiffies.h>

#define DRIVER_DESC     "Creative Labs Blaster GamePad Cobra driver"

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

#define COBRA_MAX_STROBE        45      /* 45 us max wait for first strobe */
#define COBRA_LENGTH            36

static int cobra_btn[] = { BTN_START, BTN_SELECT, BTN_TL, BTN_TR, BTN_X, BTN_Y, BTN_Z, BTN_A, BTN_B, BTN_C, BTN_TL2, BTN_TR2, 0 };

struct cobra {
        struct gameport *gameport;
        struct input_dev *dev[2];
        int reads;
        int bads;
        unsigned char exists;
        char phys[2][32];
};

static unsigned char cobra_read_packet(struct gameport *gameport, unsigned int *data)
{
        unsigned long flags;
        unsigned char u, v, w;
        __u64 buf[2];
        int r[2], t[2];
        int i, j, ret;

        int strobe = gameport_time(gameport, COBRA_MAX_STROBE);

        for (i = 0; i < 2; i++) {
                r[i] = buf[i] = 0;
                t[i] = COBRA_MAX_STROBE;
        }

        local_irq_save(flags);

        u = gameport_read(gameport);

        do {
                t[0]--; t[1]--;
                v = gameport_read(gameport);
                for (i = 0, w = u ^ v; i < 2 && w; i++, w >>= 2)
                        if (w & 0x30) {
                                if ((w & 0x30) < 0x30 && r[i] < COBRA_LENGTH && t[i] > 0) {
                                        buf[i] |= (__u64)((w >> 5) & 1) << r[i]++;
                                        t[i] = strobe;
                                        u = v;
                                } else t[i] = 0;
                        }
        } while (t[0] > 0 || t[1] > 0);

        local_irq_restore(flags);

        ret = 0;

        for (i = 0; i < 2; i++) {

                if (r[i] != COBRA_LENGTH) continue;

                for (j = 0; j < COBRA_LENGTH && (buf[i] & 0x04104107f) ^ 0x041041040; j++)
                        buf[i] = (buf[i] >> 1) | ((__u64)(buf[i] & 1) << (COBRA_LENGTH - 1));

                if (j < COBRA_LENGTH) ret |= (1 << i);

                data[i] = ((buf[i] >>  7) & 0x000001f) | ((buf[i] >>  8) & 0x00003e0)
                        | ((buf[i] >>  9) & 0x0007c00) | ((buf[i] >> 10) & 0x00f8000)
                        | ((buf[i] >> 11) & 0x1f00000);

        }

        return ret;
}

static void cobra_poll(struct gameport *gameport)
{
        struct cobra *cobra = gameport_get_drvdata(gameport);
        struct input_dev *dev;
        unsigned int data[2];
        int i, j, r;

        cobra->reads++;

        if ((r = cobra_read_packet(gameport, data)) != cobra->exists) {
                cobra->bads++;
                return;
        }

        for (i = 0; i < 2; i++)
                if (cobra->exists & r & (1 << i)) {

                        dev = cobra->dev[i];

                        input_report_abs(dev, ABS_X, ((data[i] >> 4) & 1) - ((data[i] >> 3) & 1));
                        input_report_abs(dev, ABS_Y, ((data[i] >> 2) & 1) - ((data[i] >> 1) & 1));

                        for (j = 0; cobra_btn[j]; j++)
                                input_report_key(dev, cobra_btn[j], data[i] & (0x20 << j));

                        input_sync(dev);

                }
}

static int cobra_open(struct input_dev *dev)
{
        struct cobra *cobra = input_get_drvdata(dev);

        gameport_start_polling(cobra->gameport);
        return 0;
}

static void cobra_close(struct input_dev *dev)
{
        struct cobra *cobra = input_get_drvdata(dev);

        gameport_stop_polling(cobra->gameport);
}

static int cobra_connect(struct gameport *gameport, struct gameport_driver *drv)
{
        struct cobra *cobra;
        struct input_dev *input_dev;
        unsigned int data[2];
        int i, j;
        int err;

        cobra = kzalloc_obj(*cobra);
        if (!cobra)
                return -ENOMEM;

        cobra->gameport = gameport;

        gameport_set_drvdata(gameport, cobra);

        err = gameport_open(gameport, drv, GAMEPORT_MODE_RAW);
        if (err)
                goto fail1;

        cobra->exists = cobra_read_packet(gameport, data);

        for (i = 0; i < 2; i++)
                if ((cobra->exists >> i) & data[i] & 1) {
                        printk(KERN_WARNING "cobra.c: Device %d on %s has the Ext bit set. ID is: %d"
                                " Contact vojtech@ucw.cz\n", i, gameport->phys, (data[i] >> 2) & 7);
                        cobra->exists &= ~(1 << i);
                }

        if (!cobra->exists) {
                err = -ENODEV;
                goto fail2;
        }

        gameport_set_poll_handler(gameport, cobra_poll);
        gameport_set_poll_interval(gameport, 20);

        for (i = 0; i < 2; i++) {
                if (~(cobra->exists >> i) & 1)
                        continue;

                cobra->dev[i] = input_dev = input_allocate_device();
                if (!input_dev) {
                        err = -ENOMEM;
                        goto fail3;
                }

                snprintf(cobra->phys[i], sizeof(cobra->phys[i]),
                         "%s/input%d", gameport->phys, i);

                input_dev->name = "Creative Labs Blaster GamePad Cobra";
                input_dev->phys = cobra->phys[i];
                input_dev->id.bustype = BUS_GAMEPORT;
                input_dev->id.vendor = GAMEPORT_ID_VENDOR_CREATIVE;
                input_dev->id.product = 0x0008;
                input_dev->id.version = 0x0100;
                input_dev->dev.parent = &gameport->dev;

                input_set_drvdata(input_dev, cobra);

                input_dev->open = cobra_open;
                input_dev->close = cobra_close;

                input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
                input_set_abs_params(input_dev, ABS_X, -1, 1, 0, 0);
                input_set_abs_params(input_dev, ABS_Y, -1, 1, 0, 0);
                for (j = 0; cobra_btn[j]; j++)
                        set_bit(cobra_btn[j], input_dev->keybit);

                err = input_register_device(cobra->dev[i]);
                if (err)
                        goto fail4;
        }

        return 0;

 fail4: input_free_device(cobra->dev[i]);
 fail3: while (--i >= 0)
                if (cobra->dev[i])
                        input_unregister_device(cobra->dev[i]);
 fail2: gameport_close(gameport);
 fail1: gameport_set_drvdata(gameport, NULL);
        kfree(cobra);
        return err;
}

static void cobra_disconnect(struct gameport *gameport)
{
        struct cobra *cobra = gameport_get_drvdata(gameport);
        int i;

        for (i = 0; i < 2; i++)
                if ((cobra->exists >> i) & 1)
                        input_unregister_device(cobra->dev[i]);
        gameport_close(gameport);
        gameport_set_drvdata(gameport, NULL);
        kfree(cobra);
}

static struct gameport_driver cobra_drv = {
        .driver         = {
                .name   = "cobra",
        },
        .description    = DRIVER_DESC,
        .connect        = cobra_connect,
        .disconnect     = cobra_disconnect,
};

module_gameport_driver(cobra_drv);