// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * SEGA Dreamcast keyboard driver
 * Based on drivers/usb/usbkbd.c
 * Copyright (c) YAEGASHI Takeshi, 2001
 * Porting to 2.6 Copyright (c) Adrian McMenamin, 2007 - 2009
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/maple.h>

/* Very simple mutex to ensure proper cleanup */
static DEFINE_MUTEX(maple_keyb_mutex);

#define NR_SCANCODES 256

MODULE_AUTHOR("Adrian McMenamin <adrian@mcmen.demon.co.uk");
MODULE_DESCRIPTION("SEGA Dreamcast keyboard driver");
MODULE_LICENSE("GPL");

struct dc_kbd {
        struct input_dev *dev;
        unsigned short keycode[NR_SCANCODES];
        unsigned char new[8];
        unsigned char old[8];
};

static const unsigned short dc_kbd_keycode[NR_SCANCODES] = {
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_A, KEY_B,
        KEY_C, KEY_D, KEY_E, KEY_F, KEY_G, KEY_H, KEY_I, KEY_J, KEY_K, KEY_L,
        KEY_M, KEY_N, KEY_O, KEY_P, KEY_Q, KEY_R, KEY_S, KEY_T, KEY_U, KEY_V,
        KEY_W, KEY_X, KEY_Y, KEY_Z, KEY_1, KEY_2, KEY_3, KEY_4, KEY_5, KEY_6,
        KEY_7, KEY_8, KEY_9, KEY_0, KEY_ENTER, KEY_ESC, KEY_BACKSPACE,
        KEY_TAB, KEY_SPACE, KEY_MINUS, KEY_EQUAL, KEY_LEFTBRACE,
        KEY_RIGHTBRACE, KEY_BACKSLASH, KEY_BACKSLASH, KEY_SEMICOLON,
        KEY_APOSTROPHE, KEY_GRAVE, KEY_COMMA, KEY_DOT, KEY_SLASH,
        KEY_CAPSLOCK, KEY_F1, KEY_F2, KEY_F3, KEY_F4, KEY_F5, KEY_F6,
        KEY_F7, KEY_F8, KEY_F9, KEY_F10, KEY_F11, KEY_F12, KEY_SYSRQ,
        KEY_SCROLLLOCK, KEY_PAUSE, KEY_INSERT, KEY_HOME, KEY_PAGEUP,
        KEY_DELETE, KEY_END, KEY_PAGEDOWN, KEY_RIGHT, KEY_LEFT, KEY_DOWN,
        KEY_UP, KEY_NUMLOCK, KEY_KPSLASH, KEY_KPASTERISK, KEY_KPMINUS,
        KEY_KPPLUS, KEY_KPENTER, KEY_KP1, KEY_KP2, KEY_KP3, KEY_KP4, KEY_KP5,
        KEY_KP6, KEY_KP7, KEY_KP8, KEY_KP9, KEY_KP0, KEY_KPDOT, KEY_102ND,
        KEY_COMPOSE, KEY_POWER, KEY_KPEQUAL, KEY_F13, KEY_F14, KEY_F15,
        KEY_F16, KEY_F17, KEY_F18, KEY_F19, KEY_F20, KEY_F21, KEY_F22,
        KEY_F23, KEY_F24, KEY_OPEN, KEY_HELP, KEY_PROPS, KEY_FRONT, KEY_STOP,
        KEY_AGAIN, KEY_UNDO, KEY_CUT, KEY_COPY, KEY_PASTE, KEY_FIND, KEY_MUTE,
        KEY_VOLUMEUP, KEY_VOLUMEDOWN, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_KPCOMMA, KEY_RESERVED, KEY_RO, KEY_KATAKANAHIRAGANA , KEY_YEN,
        KEY_HENKAN, KEY_MUHENKAN, KEY_KPJPCOMMA, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_HANGEUL, KEY_HANJA, KEY_KATAKANA, KEY_HIRAGANA,
        KEY_ZENKAKUHANKAKU, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED,
        KEY_RESERVED, KEY_RESERVED, KEY_LEFTCTRL, KEY_LEFTSHIFT, KEY_LEFTALT,
        KEY_LEFTMETA, KEY_RIGHTCTRL, KEY_RIGHTSHIFT, KEY_RIGHTALT,
        KEY_RIGHTMETA, KEY_PLAYPAUSE, KEY_STOPCD, KEY_PREVIOUSSONG,
        KEY_NEXTSONG, KEY_EJECTCD, KEY_VOLUMEUP, KEY_VOLUMEDOWN, KEY_MUTE,
        KEY_WWW, KEY_BACK, KEY_FORWARD, KEY_STOP, KEY_FIND, KEY_SCROLLUP,
        KEY_SCROLLDOWN, KEY_EDIT, KEY_SLEEP, KEY_SCREENLOCK, KEY_REFRESH,
        KEY_CALC, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED, KEY_RESERVED
};

static void dc_scan_kbd(struct dc_kbd *kbd)
{
        struct input_dev *dev = kbd->dev;
        void *ptr;
        int code, keycode;
        int i;

        for (i = 0; i < 8; i++) {
                code = i + 224;
                keycode = kbd->keycode[code];
                input_event(dev, EV_MSC, MSC_SCAN, code);
                input_report_key(dev, keycode, (kbd->new[0] >> i) & 1);
        }

        for (i = 2; i < 8; i++) {
                ptr = memchr(kbd->new + 2, kbd->old[i], 6);
                code = kbd->old[i];
                if (code > 3 && ptr == NULL) {
                        keycode = kbd->keycode[code];
                        if (keycode) {
                                input_event(dev, EV_MSC, MSC_SCAN, code);
                                input_report_key(dev, keycode, 0);
                        } else
                                dev_dbg(&dev->dev,
                                        "Unknown key (scancode %#x) released.",
                                        code);
                }
                ptr = memchr(kbd->old + 2, kbd->new[i], 6);
                code = kbd->new[i];
                if (code > 3 && ptr) {
                        keycode = kbd->keycode[code];
                        if (keycode) {
                                input_event(dev, EV_MSC, MSC_SCAN, code);
                                input_report_key(dev, keycode, 1);
                        } else
                                dev_dbg(&dev->dev,
                                        "Unknown key (scancode %#x) pressed.",
                                        code);
                }
        }
        input_sync(dev);
        memcpy(kbd->old, kbd->new, 8);
}

static void dc_kbd_callback(struct mapleq *mq)
{
        struct maple_device *mapledev = mq->dev;
        struct dc_kbd *kbd = maple_get_drvdata(mapledev);
        unsigned long *buf = (unsigned long *)(mq->recvbuf->buf);

        /*
         * We should always get the lock because the only
         * time it may be locked is if the driver is in the cleanup phase.
         */
        scoped_guard(mutex_try, &maple_keyb_mutex) {
                if (buf[1] == mapledev->function) {
                        memcpy(kbd->new, buf + 2, 8);
                        dc_scan_kbd(kbd);
                }
        }
}

static int probe_maple_kbd(struct device *dev)
{
        struct maple_device *mdev;
        struct maple_driver *mdrv;
        int i, error;
        struct dc_kbd *kbd;
        struct input_dev *idev;

        mdev = to_maple_dev(dev);
        mdrv = to_maple_driver(dev->driver);

        kbd = kzalloc_obj(*kbd);
        if (!kbd) {
                error = -ENOMEM;
                goto fail;
        }

        idev = input_allocate_device();
        if (!idev) {
                error = -ENOMEM;
                goto fail_idev_alloc;
        }

        kbd->dev = idev;
        memcpy(kbd->keycode, dc_kbd_keycode, sizeof(kbd->keycode));

        idev->name = mdev->product_name;
        idev->evbit[0] = BIT(EV_KEY) | BIT(EV_REP);
        idev->keycode = kbd->keycode;
        idev->keycodesize = sizeof(unsigned short);
        idev->keycodemax = ARRAY_SIZE(kbd->keycode);
        idev->id.bustype = BUS_HOST;
        idev->dev.parent = &mdev->dev;

        for (i = 0; i < NR_SCANCODES; i++)
                __set_bit(dc_kbd_keycode[i], idev->keybit);
        __clear_bit(KEY_RESERVED, idev->keybit);

        input_set_capability(idev, EV_MSC, MSC_SCAN);

        error = input_register_device(idev);
        if (error)
                goto fail_register;

        /* Maple polling is locked to VBLANK - which may be just 50/s */
        maple_getcond_callback(mdev, dc_kbd_callback, HZ/50,
                MAPLE_FUNC_KEYBOARD);

        mdev->driver = mdrv;

        maple_set_drvdata(mdev, kbd);

        return error;

fail_register:
        maple_set_drvdata(mdev, NULL);
        input_free_device(idev);
fail_idev_alloc:
        kfree(kbd);
fail:
        return error;
}

static int remove_maple_kbd(struct device *dev)
{
        struct maple_device *mdev = to_maple_dev(dev);
        struct dc_kbd *kbd = maple_get_drvdata(mdev);

        guard(mutex)(&maple_keyb_mutex);

        input_unregister_device(kbd->dev);
        kfree(kbd);

        maple_set_drvdata(mdev, NULL);
        return 0;
}

static struct maple_driver dc_kbd_driver = {
        .function = MAPLE_FUNC_KEYBOARD,
        .drv = {
                .name = "Dreamcast_keyboard",
                .probe = probe_maple_kbd,
                .remove = remove_maple_kbd,
        },
};

static int __init dc_kbd_init(void)
{
        return maple_driver_register(&dc_kbd_driver);
}

static void __exit dc_kbd_exit(void)
{
        maple_driver_unregister(&dc_kbd_driver);
}

module_init(dc_kbd_init);
module_exit(dc_kbd_exit);