/*
 * HID driver for Nintendo Wii / Wii U peripherals
 * Copyright (c) 2011-2013 David Herrmann <dh.herrmann@gmail.com>
 */

/*
 * 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.
 */

#include <linux/completion.h>
#include <linux/device.h>
#include <linux/hid.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include "hid-ids.h"
#include "hid-wiimote.h"

/* output queue handling */

static int wiimote_hid_send(struct hid_device *hdev, __u8 *buffer,
                            size_t count)
{
        __u8 *buf;
        int ret;

        if (!hdev->ll_driver->output_report)
                return -ENODEV;

        buf = kmemdup(buffer, count, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        ret = hid_hw_output_report(hdev, buf, count);

        kfree(buf);
        return ret;
}

static void wiimote_queue_worker(struct work_struct *work)
{
        struct wiimote_queue *queue = container_of(work, struct wiimote_queue,
                                                   worker);
        struct wiimote_data *wdata = container_of(queue, struct wiimote_data,
                                                  queue);
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&wdata->queue.lock, flags);

        while (wdata->queue.head != wdata->queue.tail) {
                spin_unlock_irqrestore(&wdata->queue.lock, flags);
                ret = wiimote_hid_send(wdata->hdev,
                                 wdata->queue.outq[wdata->queue.tail].data,
                                 wdata->queue.outq[wdata->queue.tail].size);
                if (ret < 0) {
                        spin_lock_irqsave(&wdata->state.lock, flags);
                        wiimote_cmd_abort(wdata);
                        spin_unlock_irqrestore(&wdata->state.lock, flags);
                }
                spin_lock_irqsave(&wdata->queue.lock, flags);

                wdata->queue.tail = (wdata->queue.tail + 1) % WIIMOTE_BUFSIZE;
        }

        spin_unlock_irqrestore(&wdata->queue.lock, flags);
}

static void wiimote_queue(struct wiimote_data *wdata, const __u8 *buffer,
                                                                size_t count)
{
        unsigned long flags;
        __u8 newhead;

        if (count > HID_MAX_BUFFER_SIZE) {
                hid_warn(wdata->hdev, "Sending too large output report\n");

                spin_lock_irqsave(&wdata->queue.lock, flags);
                goto out_error;
        }

        /*
         * Copy new request into our output queue and check whether the
         * queue is full. If it is full, discard this request.
         * If it is empty we need to start a new worker that will
         * send out the buffer to the hid device.
         * If the queue is not empty, then there must be a worker
         * that is currently sending out our buffer and this worker
         * will reschedule itself until the queue is empty.
         */

        spin_lock_irqsave(&wdata->queue.lock, flags);

        memcpy(wdata->queue.outq[wdata->queue.head].data, buffer, count);
        wdata->queue.outq[wdata->queue.head].size = count;
        newhead = (wdata->queue.head + 1) % WIIMOTE_BUFSIZE;

        if (wdata->queue.head == wdata->queue.tail) {
                wdata->queue.head = newhead;
                schedule_work(&wdata->queue.worker);
        } else if (newhead != wdata->queue.tail) {
                wdata->queue.head = newhead;
        } else {
                hid_warn(wdata->hdev, "Output queue is full");
                goto out_error;
        }

        goto out_unlock;

out_error:
        wiimote_cmd_abort(wdata);
out_unlock:
        spin_unlock_irqrestore(&wdata->queue.lock, flags);
}

/*
 * This sets the rumble bit on the given output report if rumble is
 * currently enabled.
 * \cmd1 must point to the second byte in the output report => &cmd[1]
 * This must be called on nearly every output report before passing it
 * into the output queue!
 */
static inline void wiiproto_keep_rumble(struct wiimote_data *wdata, __u8 *cmd1)
{
        if (wdata->state.flags & WIIPROTO_FLAG_RUMBLE)
                *cmd1 |= 0x01;
}

void wiiproto_req_rumble(struct wiimote_data *wdata, __u8 rumble)
{
        __u8 cmd[2];

        rumble = !!rumble;
        if (rumble == !!(wdata->state.flags & WIIPROTO_FLAG_RUMBLE))
                return;

        if (rumble)
                wdata->state.flags |= WIIPROTO_FLAG_RUMBLE;
        else
                wdata->state.flags &= ~WIIPROTO_FLAG_RUMBLE;

        cmd[0] = WIIPROTO_REQ_RUMBLE;
        cmd[1] = 0;

        wiiproto_keep_rumble(wdata, &cmd[1]);
        wiimote_queue(wdata, cmd, sizeof(cmd));
}

void wiiproto_req_leds(struct wiimote_data *wdata, int leds)
{
        __u8 cmd[2];

        leds &= WIIPROTO_FLAGS_LEDS;
        if ((wdata->state.flags & WIIPROTO_FLAGS_LEDS) == leds)
                return;
        wdata->state.flags = (wdata->state.flags & ~WIIPROTO_FLAGS_LEDS) | leds;

        cmd[0] = WIIPROTO_REQ_LED;
        cmd[1] = 0;

        if (leds & WIIPROTO_FLAG_LED1)
                cmd[1] |= 0x10;
        if (leds & WIIPROTO_FLAG_LED2)
                cmd[1] |= 0x20;
        if (leds & WIIPROTO_FLAG_LED3)
                cmd[1] |= 0x40;
        if (leds & WIIPROTO_FLAG_LED4)
                cmd[1] |= 0x80;

        wiiproto_keep_rumble(wdata, &cmd[1]);
        wiimote_queue(wdata, cmd, sizeof(cmd));
}

/*
 * Check what peripherals of the wiimote are currently
 * active and select a proper DRM that supports all of
 * the requested data inputs.
 *
 * Not all combinations are actually supported. The following
 * combinations work only with limitations:
 *  - IR cam in extended or full mode disables any data transmission
 *    of extension controllers. There is no DRM mode that supports
 *    extension bytes plus extended/full IR.
 *  - IR cam with accelerometer and extension *_EXT8 is not supported.
 *    However, all extensions that need *_EXT8 are devices that don't
 *    support IR cameras. Hence, this shouldn't happen under normal
 *    operation.
 *  - *_EXT16 is only supported in combination with buttons and
 *    accelerometer. No IR or similar can be active simultaneously. As
 *    above, all modules that require it are mutually exclusive with
 *    IR/etc. so this doesn't matter.
 */
static __u8 select_drm(struct wiimote_data *wdata)
{
        __u8 ir = wdata->state.flags & WIIPROTO_FLAGS_IR;
        bool ext;

        ext = (wdata->state.flags & WIIPROTO_FLAG_EXT_USED) ||
              (wdata->state.flags & WIIPROTO_FLAG_MP_USED);

        /* some 3rd-party balance-boards are hard-coded to KEE, *sigh* */
        if (wdata->state.devtype == WIIMOTE_DEV_BALANCE_BOARD) {
                if (ext)
                        return WIIPROTO_REQ_DRM_KEE;
                else
                        return WIIPROTO_REQ_DRM_K;
        }

        if (ir == WIIPROTO_FLAG_IR_BASIC) {
                if (wdata->state.flags & WIIPROTO_FLAG_ACCEL) {
                        /* GEN10 and ealier devices bind IR formats to DRMs.
                         * Hence, we cannot use DRM_KAI here as it might be
                         * bound to IR_EXT. Use DRM_KAIE unconditionally so we
                         * work with all devices and our parsers can use the
                         * fixed formats, too. */
                        return WIIPROTO_REQ_DRM_KAIE;
                } else {
                        return WIIPROTO_REQ_DRM_KIE;
                }
        } else if (ir == WIIPROTO_FLAG_IR_EXT) {
                return WIIPROTO_REQ_DRM_KAI;
        } else if (ir == WIIPROTO_FLAG_IR_FULL) {
                return WIIPROTO_REQ_DRM_SKAI1;
        } else {
                if (wdata->state.flags & WIIPROTO_FLAG_ACCEL) {
                        if (ext)
                                return WIIPROTO_REQ_DRM_KAE;
                        else
                                return WIIPROTO_REQ_DRM_KA;
                } else {
                        if (ext)
                                return WIIPROTO_REQ_DRM_KEE;
                        else
                                return WIIPROTO_REQ_DRM_K;
                }
        }
}

void wiiproto_req_drm(struct wiimote_data *wdata, __u8 drm)
{
        __u8 cmd[3];

        if (wdata->state.flags & WIIPROTO_FLAG_DRM_LOCKED)
                drm = wdata->state.drm;
        else if (drm == WIIPROTO_REQ_NULL)
                drm = select_drm(wdata);

        cmd[0] = WIIPROTO_REQ_DRM;
        cmd[1] = 0;
        cmd[2] = drm;

        wdata->state.drm = drm;
        wiiproto_keep_rumble(wdata, &cmd[1]);
        wiimote_queue(wdata, cmd, sizeof(cmd));
}

void wiiproto_req_status(struct wiimote_data *wdata)
{
        __u8 cmd[2];

        cmd[0] = WIIPROTO_REQ_SREQ;
        cmd[1] = 0;

        wiiproto_keep_rumble(wdata, &cmd[1]);
        wiimote_queue(wdata, cmd, sizeof(cmd));
}

void wiiproto_req_accel(struct wiimote_data *wdata, __u8 accel)
{
        accel = !!accel;
        if (accel == !!(wdata->state.flags & WIIPROTO_FLAG_ACCEL))
                return;

        if (accel)
                wdata->state.flags |= WIIPROTO_FLAG_ACCEL;
        else
                wdata->state.flags &= ~WIIPROTO_FLAG_ACCEL;

        wiiproto_req_drm(wdata, WIIPROTO_REQ_NULL);
}

void wiiproto_req_ir1(struct wiimote_data *wdata, __u8 flags)
{
        __u8 cmd[2];

        cmd[0] = WIIPROTO_REQ_IR1;
        cmd[1] = flags;

        wiiproto_keep_rumble(wdata, &cmd[1]);
        wiimote_queue(wdata, cmd, sizeof(cmd));
}

void wiiproto_req_ir2(struct wiimote_data *wdata, __u8 flags)
{
        __u8 cmd[2];

        cmd[0] = WIIPROTO_REQ_IR2;
        cmd[1] = flags;

        wiiproto_keep_rumble(wdata, &cmd[1]);
        wiimote_queue(wdata, cmd, sizeof(cmd));
}

#define wiiproto_req_wreg(wdata, os, buf, sz) \
                        wiiproto_req_wmem((wdata), false, (os), (buf), (sz))

#define wiiproto_req_weeprom(wdata, os, buf, sz) \
                        wiiproto_req_wmem((wdata), true, (os), (buf), (sz))

static void wiiproto_req_wmem(struct wiimote_data *wdata, bool eeprom,
                                __u32 offset, const __u8 *buf, __u8 size)
{
        __u8 cmd[22];

        if (size > 16 || size == 0) {
                hid_warn(wdata->hdev, "Invalid length %d wmem request\n", size);
                return;
        }

        memset(cmd, 0, sizeof(cmd));
        cmd[0] = WIIPROTO_REQ_WMEM;
        cmd[2] = (offset >> 16) & 0xff;
        cmd[3] = (offset >> 8) & 0xff;
        cmd[4] = offset & 0xff;
        cmd[5] = size;
        memcpy(&cmd[6], buf, size);

        if (!eeprom)
                cmd[1] |= 0x04;

        wiiproto_keep_rumble(wdata, &cmd[1]);
        wiimote_queue(wdata, cmd, sizeof(cmd));
}

void wiiproto_req_rmem(struct wiimote_data *wdata, bool eeprom, __u32 offset,
                                                                __u16 size)
{
        __u8 cmd[7];

        if (size == 0) {
                hid_warn(wdata->hdev, "Invalid length %d rmem request\n", size);
                return;
        }

        cmd[0] = WIIPROTO_REQ_RMEM;
        cmd[1] = 0;
        cmd[2] = (offset >> 16) & 0xff;
        cmd[3] = (offset >> 8) & 0xff;
        cmd[4] = offset & 0xff;
        cmd[5] = (size >> 8) & 0xff;
        cmd[6] = size & 0xff;

        if (!eeprom)
                cmd[1] |= 0x04;

        wiiproto_keep_rumble(wdata, &cmd[1]);
        wiimote_queue(wdata, cmd, sizeof(cmd));
}

/* requries the cmd-mutex to be held */
int wiimote_cmd_write(struct wiimote_data *wdata, __u32 offset,
                                                const __u8 *wmem, __u8 size)
{
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&wdata->state.lock, flags);
        wiimote_cmd_set(wdata, WIIPROTO_REQ_WMEM, 0);
        wiiproto_req_wreg(wdata, offset, wmem, size);
        spin_unlock_irqrestore(&wdata->state.lock, flags);

        ret = wiimote_cmd_wait(wdata);
        if (!ret && wdata->state.cmd_err)
                ret = -EIO;

        return ret;
}

/* requries the cmd-mutex to be held */
ssize_t wiimote_cmd_read(struct wiimote_data *wdata, __u32 offset, __u8 *rmem,
                                                                __u8 size)
{
        unsigned long flags;
        ssize_t ret;

        spin_lock_irqsave(&wdata->state.lock, flags);
        wdata->state.cmd_read_size = size;
        wdata->state.cmd_read_buf = rmem;
        wiimote_cmd_set(wdata, WIIPROTO_REQ_RMEM, offset & 0xffff);
        wiiproto_req_rreg(wdata, offset, size);
        spin_unlock_irqrestore(&wdata->state.lock, flags);

        ret = wiimote_cmd_wait(wdata);

        spin_lock_irqsave(&wdata->state.lock, flags);
        wdata->state.cmd_read_buf = NULL;
        spin_unlock_irqrestore(&wdata->state.lock, flags);

        if (!ret) {
                if (wdata->state.cmd_read_size == 0)
                        ret = -EIO;
                else
                        ret = wdata->state.cmd_read_size;
        }

        return ret;
}

/* requires the cmd-mutex to be held */
static int wiimote_cmd_init_ext(struct wiimote_data *wdata)
{
        __u8 wmem;
        int ret;

        /* initialize extension */
        wmem = 0x55;
        ret = wiimote_cmd_write(wdata, 0xa400f0, &wmem, sizeof(wmem));
        if (ret)
                return ret;

        /* disable default encryption */
        wmem = 0x0;
        ret = wiimote_cmd_write(wdata, 0xa400fb, &wmem, sizeof(wmem));
        if (ret)
                return ret;

        return 0;
}

/* requires the cmd-mutex to be held */
static __u8 wiimote_cmd_read_ext(struct wiimote_data *wdata, __u8 *rmem)
{
        int ret;

        /* read extension ID */
        ret = wiimote_cmd_read(wdata, 0xa400fa, rmem, 6);
        if (ret != 6)
                return WIIMOTE_EXT_NONE;

        hid_dbg(wdata->hdev, "extension ID: %6phC\n", rmem);

        if (rmem[0] == 0xff && rmem[1] == 0xff && rmem[2] == 0xff &&
            rmem[3] == 0xff && rmem[4] == 0xff && rmem[5] == 0xff)
                return WIIMOTE_EXT_NONE;

        if (rmem[4] == 0x00 && rmem[5] == 0x00)
                return WIIMOTE_EXT_NUNCHUK;
        if (rmem[4] == 0x01 && rmem[5] == 0x01)
                return WIIMOTE_EXT_CLASSIC_CONTROLLER;
        if (rmem[4] == 0x04 && rmem[5] == 0x02)
                return WIIMOTE_EXT_BALANCE_BOARD;
        if (rmem[4] == 0x01 && rmem[5] == 0x20)
                return WIIMOTE_EXT_PRO_CONTROLLER;
        if (rmem[0] == 0x01 && rmem[1] == 0x00 &&
            rmem[4] == 0x01 && rmem[5] == 0x03)
                return WIIMOTE_EXT_DRUMS;
        if (rmem[0] == 0x00 && rmem[1] == 0x00 &&
            rmem[4] == 0x01 && rmem[5] == 0x03)
                return WIIMOTE_EXT_GUITAR;

        return WIIMOTE_EXT_UNKNOWN;
}

/* requires the cmd-mutex to be held */
static int wiimote_cmd_init_mp(struct wiimote_data *wdata)
{
        __u8 wmem;
        int ret;

        /* initialize MP */
        wmem = 0x55;
        ret = wiimote_cmd_write(wdata, 0xa600f0, &wmem, sizeof(wmem));
        if (ret)
                return ret;

        /* disable default encryption */
        wmem = 0x0;
        ret = wiimote_cmd_write(wdata, 0xa600fb, &wmem, sizeof(wmem));
        if (ret)
                return ret;

        return 0;
}

/* requires the cmd-mutex to be held */
static bool wiimote_cmd_map_mp(struct wiimote_data *wdata, __u8 exttype)
{
        __u8 wmem;

        /* map MP with correct pass-through mode */
        switch (exttype) {
        case WIIMOTE_EXT_CLASSIC_CONTROLLER:
        case WIIMOTE_EXT_DRUMS:
        case WIIMOTE_EXT_GUITAR:
                wmem = 0x07;
                break;
        case WIIMOTE_EXT_NUNCHUK:
                wmem = 0x05;
                break;
        default:
                wmem = 0x04;
                break;
        }

        return wiimote_cmd_write(wdata, 0xa600fe, &wmem, sizeof(wmem));
}

/* requires the cmd-mutex to be held */
static bool wiimote_cmd_read_mp(struct wiimote_data *wdata, __u8 *rmem)
{
        int ret;

        /* read motion plus ID */
        ret = wiimote_cmd_read(wdata, 0xa600fa, rmem, 6);
        if (ret != 6)
                return false;

        hid_dbg(wdata->hdev, "motion plus ID: %6phC\n", rmem);

        if (rmem[5] == 0x05)
                return true;

        hid_info(wdata->hdev, "unknown motion plus ID: %6phC\n", rmem);

        return false;
}

/* requires the cmd-mutex to be held */
static __u8 wiimote_cmd_read_mp_mapped(struct wiimote_data *wdata)
{
        int ret;
        __u8 rmem[6];

        /* read motion plus ID */
        ret = wiimote_cmd_read(wdata, 0xa400fa, rmem, 6);
        if (ret != 6)
                return WIIMOTE_MP_NONE;

        hid_dbg(wdata->hdev, "mapped motion plus ID: %6phC\n", rmem);

        if (rmem[0] == 0xff && rmem[1] == 0xff && rmem[2] == 0xff &&
            rmem[3] == 0xff && rmem[4] == 0xff && rmem[5] == 0xff)
                return WIIMOTE_MP_NONE;

        if (rmem[4] == 0x04 && rmem[5] == 0x05)
                return WIIMOTE_MP_SINGLE;
        else if (rmem[4] == 0x05 && rmem[5] == 0x05)
                return WIIMOTE_MP_PASSTHROUGH_NUNCHUK;
        else if (rmem[4] == 0x07 && rmem[5] == 0x05)
                return WIIMOTE_MP_PASSTHROUGH_CLASSIC;

        return WIIMOTE_MP_UNKNOWN;
}

/* device module handling */

static const __u8 * const wiimote_devtype_mods[WIIMOTE_DEV_NUM] = {
        [WIIMOTE_DEV_PENDING] = (const __u8[]){
                WIIMOD_NULL,
        },
        [WIIMOTE_DEV_UNKNOWN] = (const __u8[]){
                WIIMOD_NO_MP,
                WIIMOD_NULL,
        },
        [WIIMOTE_DEV_GENERIC] = (const __u8[]){
                WIIMOD_KEYS,
                WIIMOD_RUMBLE,
                WIIMOD_BATTERY,
                WIIMOD_LED1,
                WIIMOD_LED2,
                WIIMOD_LED3,
                WIIMOD_LED4,
                WIIMOD_ACCEL,
                WIIMOD_IR,
                WIIMOD_NULL,
        },
        [WIIMOTE_DEV_GEN10] = (const __u8[]){
                WIIMOD_KEYS,
                WIIMOD_RUMBLE,
                WIIMOD_BATTERY,
                WIIMOD_LED1,
                WIIMOD_LED2,
                WIIMOD_LED3,
                WIIMOD_LED4,
                WIIMOD_ACCEL,
                WIIMOD_IR,
                WIIMOD_NULL,
        },
        [WIIMOTE_DEV_GEN20] = (const __u8[]){
                WIIMOD_KEYS,
                WIIMOD_RUMBLE,
                WIIMOD_BATTERY,
                WIIMOD_LED1,
                WIIMOD_LED2,
                WIIMOD_LED3,
                WIIMOD_LED4,
                WIIMOD_ACCEL,
                WIIMOD_IR,
                WIIMOD_BUILTIN_MP,
                WIIMOD_NULL,
        },
        [WIIMOTE_DEV_BALANCE_BOARD] = (const __u8[]) {
                WIIMOD_BATTERY,
                WIIMOD_LED1,
                WIIMOD_NO_MP,
                WIIMOD_NULL,
        },
        [WIIMOTE_DEV_PRO_CONTROLLER] = (const __u8[]) {
                WIIMOD_BATTERY,
                WIIMOD_LED1,
                WIIMOD_LED2,
                WIIMOD_LED3,
                WIIMOD_LED4,
                WIIMOD_NO_MP,
                WIIMOD_NULL,
        },
};

static void wiimote_modules_load(struct wiimote_data *wdata,
                                 unsigned int devtype)
{
        bool need_input = false;
        const __u8 *mods, *iter;
        const struct wiimod_ops *ops;
        int ret;

        mods = wiimote_devtype_mods[devtype];

        for (iter = mods; *iter != WIIMOD_NULL; ++iter) {
                if (wiimod_table[*iter]->flags & WIIMOD_FLAG_INPUT) {
                        need_input = true;
                        break;
                }
        }

        if (need_input) {
                wdata->input = input_allocate_device();
                if (!wdata->input)
                        return;

                input_set_drvdata(wdata->input, wdata);
                wdata->input->dev.parent = &wdata->hdev->dev;
                wdata->input->id.bustype = wdata->hdev->bus;
                wdata->input->id.vendor = wdata->hdev->vendor;
                wdata->input->id.product = wdata->hdev->product;
                wdata->input->id.version = wdata->hdev->version;
                wdata->input->name = WIIMOTE_NAME;
        }

        for (iter = mods; *iter != WIIMOD_NULL; ++iter) {
                ops = wiimod_table[*iter];
                if (!ops->probe)
                        continue;

                ret = ops->probe(ops, wdata);
                if (ret)
                        goto error;
        }

        if (wdata->input) {
                ret = input_register_device(wdata->input);
                if (ret)
                        goto error;
        }

        spin_lock_irq(&wdata->state.lock);
        wdata->state.devtype = devtype;
        spin_unlock_irq(&wdata->state.lock);
        return;

error:
        for ( ; iter-- != mods; ) {
                ops = wiimod_table[*iter];
                if (ops->remove)
                        ops->remove(ops, wdata);
        }

        if (wdata->input) {
                input_free_device(wdata->input);
                wdata->input = NULL;
        }
}

static void wiimote_modules_unload(struct wiimote_data *wdata)
{
        const __u8 *mods, *iter;
        const struct wiimod_ops *ops;
        unsigned long flags;

        mods = wiimote_devtype_mods[wdata->state.devtype];

        spin_lock_irqsave(&wdata->state.lock, flags);
        wdata->state.devtype = WIIMOTE_DEV_UNKNOWN;
        spin_unlock_irqrestore(&wdata->state.lock, flags);

        /* find end of list */
        for (iter = mods; *iter != WIIMOD_NULL; ++iter)
                /* empty */ ;

        if (wdata->input) {
                input_get_device(wdata->input);
                input_unregister_device(wdata->input);
        }

        for ( ; iter-- != mods; ) {
                ops = wiimod_table[*iter];
                if (ops->remove)
                        ops->remove(ops, wdata);
        }

        if (wdata->input) {
                input_put_device(wdata->input);
                wdata->input = NULL;
        }
}

/* device extension handling */

static void wiimote_ext_load(struct wiimote_data *wdata, unsigned int ext)
{
        unsigned long flags;
        const struct wiimod_ops *ops;
        int ret;

        ops = wiimod_ext_table[ext];

        if (ops->probe) {
                ret = ops->probe(ops, wdata);
                if (ret)
                        ext = WIIMOTE_EXT_UNKNOWN;
        }

        spin_lock_irqsave(&wdata->state.lock, flags);
        wdata->state.exttype = ext;
        spin_unlock_irqrestore(&wdata->state.lock, flags);
}

static void wiimote_ext_unload(struct wiimote_data *wdata)
{
        unsigned long flags;
        const struct wiimod_ops *ops;

        ops = wiimod_ext_table[wdata->state.exttype];

        spin_lock_irqsave(&wdata->state.lock, flags);
        wdata->state.exttype = WIIMOTE_EXT_UNKNOWN;
        wdata->state.flags &= ~WIIPROTO_FLAG_EXT_USED;
        spin_unlock_irqrestore(&wdata->state.lock, flags);

        if (ops->remove)
                ops->remove(ops, wdata);
}

static void wiimote_mp_load(struct wiimote_data *wdata)
{
        unsigned long flags;
        const struct wiimod_ops *ops;
        int ret;
        __u8 mode = 2;

        ops = &wiimod_mp;
        if (ops->probe) {
                ret = ops->probe(ops, wdata);
                if (ret)
                        mode = 1;
        }

        spin_lock_irqsave(&wdata->state.lock, flags);
        wdata->state.mp = mode;
        spin_unlock_irqrestore(&wdata->state.lock, flags);
}

static void wiimote_mp_unload(struct wiimote_data *wdata)
{
        unsigned long flags;
        const struct wiimod_ops *ops;

        if (wdata->state.mp < 2)
                return;

        ops = &wiimod_mp;

        spin_lock_irqsave(&wdata->state.lock, flags);
        wdata->state.mp = 0;
        wdata->state.flags &= ~WIIPROTO_FLAG_MP_USED;
        spin_unlock_irqrestore(&wdata->state.lock, flags);

        if (ops->remove)
                ops->remove(ops, wdata);
}

/* device (re-)initialization and detection */

static const char *wiimote_devtype_names[WIIMOTE_DEV_NUM] = {
        [WIIMOTE_DEV_PENDING] = "Pending",
        [WIIMOTE_DEV_UNKNOWN] = "Unknown",
        [WIIMOTE_DEV_GENERIC] = "Generic",
        [WIIMOTE_DEV_GEN10] = "Nintendo Wii Remote (Gen 1)",
        [WIIMOTE_DEV_GEN20] = "Nintendo Wii Remote Plus (Gen 2)",
        [WIIMOTE_DEV_BALANCE_BOARD] = "Nintendo Wii Balance Board",
        [WIIMOTE_DEV_PRO_CONTROLLER] = "Nintendo Wii U Pro Controller",
};

/* Try to guess the device type based on all collected information. We
 * first try to detect by static extension types, then VID/PID and the
 * device name. If we cannot detect the device, we use
 * WIIMOTE_DEV_GENERIC so all modules will get probed on the device. */
static void wiimote_init_set_type(struct wiimote_data *wdata,
                                  __u8 exttype)
{
        __u8 devtype = WIIMOTE_DEV_GENERIC;
        __u16 vendor, product;
        const char *name;

        vendor = wdata->hdev->vendor;
        product = wdata->hdev->product;
        name = wdata->hdev->name;

        if (exttype == WIIMOTE_EXT_BALANCE_BOARD) {
                devtype = WIIMOTE_DEV_BALANCE_BOARD;
                goto done;
        } else if (exttype == WIIMOTE_EXT_PRO_CONTROLLER) {
                devtype = WIIMOTE_DEV_PRO_CONTROLLER;
                goto done;
        }

        if (!strcmp(name, "Nintendo RVL-CNT-01")) {
                devtype = WIIMOTE_DEV_GEN10;
                goto done;
        } else if (!strcmp(name, "Nintendo RVL-CNT-01-TR")) {
                devtype = WIIMOTE_DEV_GEN20;
                goto done;
        } else if (!strcmp(name, "Nintendo RVL-WBC-01")) {
                devtype = WIIMOTE_DEV_BALANCE_BOARD;
                goto done;
        } else if (!strcmp(name, "Nintendo RVL-CNT-01-UC")) {
                devtype = WIIMOTE_DEV_PRO_CONTROLLER;
                goto done;
        }

        if (vendor == USB_VENDOR_ID_NINTENDO) {
                if (product == USB_DEVICE_ID_NINTENDO_WIIMOTE) {
                        devtype = WIIMOTE_DEV_GEN10;
                        goto done;
                } else if (product == USB_DEVICE_ID_NINTENDO_WIIMOTE2) {
                        devtype = WIIMOTE_DEV_GEN20;
                        goto done;
                }
        }

done:
        if (devtype == WIIMOTE_DEV_GENERIC)
                hid_info(wdata->hdev, "cannot detect device; NAME: %s VID: %04x PID: %04x EXT: %04x\n",
                        name, vendor, product, exttype);
        else
                hid_info(wdata->hdev, "detected device: %s\n",
                         wiimote_devtype_names[devtype]);

        wiimote_modules_load(wdata, devtype);
}

static void wiimote_init_detect(struct wiimote_data *wdata)
{
        __u8 exttype = WIIMOTE_EXT_NONE, extdata[6];
        bool ext;
        int ret;

        wiimote_cmd_acquire_noint(wdata);

        spin_lock_irq(&wdata->state.lock);
        wdata->state.devtype = WIIMOTE_DEV_UNKNOWN;
        wiimote_cmd_set(wdata, WIIPROTO_REQ_SREQ, 0);
        wiiproto_req_status(wdata);
        spin_unlock_irq(&wdata->state.lock);

        ret = wiimote_cmd_wait_noint(wdata);
        if (ret)
                goto out_release;

        spin_lock_irq(&wdata->state.lock);
        ext = wdata->state.flags & WIIPROTO_FLAG_EXT_PLUGGED;
        spin_unlock_irq(&wdata->state.lock);

        if (!ext)
                goto out_release;

        wiimote_cmd_init_ext(wdata);
        exttype = wiimote_cmd_read_ext(wdata, extdata);

out_release:
        wiimote_cmd_release(wdata);
        wiimote_init_set_type(wdata, exttype);

        /* schedule MP timer */
        spin_lock_irq(&wdata->state.lock);
        if (!(wdata->state.flags & WIIPROTO_FLAG_BUILTIN_MP) &&
            !(wdata->state.flags & WIIPROTO_FLAG_NO_MP))
                mod_timer(&wdata->timer, jiffies + HZ * 4);
        spin_unlock_irq(&wdata->state.lock);
}

/*
 * MP hotplug events are not generated by the wiimote. Therefore, we need
 * polling to detect it. We use a 4s interval for polling MP registers. This
 * seems reasonable considering applications can trigger it manually via
 * sysfs requests.
 */
static void wiimote_init_poll_mp(struct wiimote_data *wdata)
{
        bool mp;
        __u8 mpdata[6];

        wiimote_cmd_acquire_noint(wdata);
        wiimote_cmd_init_mp(wdata);
        mp = wiimote_cmd_read_mp(wdata, mpdata);
        wiimote_cmd_release(wdata);

        /* load/unload MP module if it changed */
        if (mp) {
                if (!wdata->state.mp) {
                        hid_info(wdata->hdev, "detected extension: Nintendo Wii Motion Plus\n");
                        wiimote_mp_load(wdata);
                }
        } else if (wdata->state.mp) {
                wiimote_mp_unload(wdata);
        }

        mod_timer(&wdata->timer, jiffies + HZ * 4);
}

/*
 * Check whether the wiimote is in the expected state. The extension registers
 * may change during hotplug and initialization so we might get hotplug events
 * that we caused by remapping some memory.
 * We use some heuristics here to check known states. If the wiimote is in the
 * expected state, we can ignore the hotplug event.
 *
 * Returns "true" if the device is in expected state, "false" if we should
 * redo hotplug handling and extension initialization.
 */
static bool wiimote_init_check(struct wiimote_data *wdata)
{
        __u32 flags;
        __u8 type, data[6];
        bool ret, poll_mp;

        spin_lock_irq(&wdata->state.lock);
        flags = wdata->state.flags;
        spin_unlock_irq(&wdata->state.lock);

        wiimote_cmd_acquire_noint(wdata);

        /* If MP is used and active, but the extension is not, we expect:
         *   read_mp_mapped() == WIIMOTE_MP_SINGLE
         *   state.flags == !EXT_ACTIVE && !MP_PLUGGED && MP_ACTIVE
         * We do not check EXT_PLUGGED because it might change during
         * initialization of MP without extensions.
         *  - If MP is unplugged/replugged, read_mp_mapped() fails
         *  - If EXT is plugged, MP_PLUGGED will get set */
        if (wdata->state.exttype == WIIMOTE_EXT_NONE &&
            wdata->state.mp > 0 && (flags & WIIPROTO_FLAG_MP_USED)) {
                type = wiimote_cmd_read_mp_mapped(wdata);
                ret = type == WIIMOTE_MP_SINGLE;

                spin_lock_irq(&wdata->state.lock);
                ret = ret && !(wdata->state.flags & WIIPROTO_FLAG_EXT_ACTIVE);
                ret = ret && !(wdata->state.flags & WIIPROTO_FLAG_MP_PLUGGED);
                ret = ret && (wdata->state.flags & WIIPROTO_FLAG_MP_ACTIVE);
                spin_unlock_irq(&wdata->state.lock);

                if (!ret)
                        hid_dbg(wdata->hdev, "state left: !EXT && MP\n");

                /* while MP is mapped, we get EXT_PLUGGED events */
                poll_mp = false;

                goto out_release;
        }

        /* If MP is unused, but the extension port is used, we expect:
         *   read_ext == state.exttype
         *   state.flags == !MP_ACTIVE && EXT_ACTIVE
         * - If MP is plugged/unplugged, our timer detects it
         * - If EXT is unplugged/replugged, EXT_ACTIVE will become unset */
        if (!(flags & WIIPROTO_FLAG_MP_USED) &&
            wdata->state.exttype != WIIMOTE_EXT_NONE) {
                type = wiimote_cmd_read_ext(wdata, data);
                ret = type == wdata->state.exttype;

                spin_lock_irq(&wdata->state.lock);
                ret = ret && !(wdata->state.flags & WIIPROTO_FLAG_MP_ACTIVE);
                ret = ret && (wdata->state.flags & WIIPROTO_FLAG_EXT_ACTIVE);
                spin_unlock_irq(&wdata->state.lock);

                if (!ret)
                        hid_dbg(wdata->hdev, "state left: EXT && !MP\n");

                /* poll MP for hotplug events */
                poll_mp = true;

                goto out_release;
        }

        /* If neither MP nor an extension are used, we expect:
         *   read_ext() == WIIMOTE_EXT_NONE
         *   state.flags == !MP_ACTIVE && !EXT_ACTIVE && !EXT_PLUGGED
         * No need to perform any action in this case as everything is
         * disabled already.
         * - If MP is plugged/unplugged, our timer detects it
         * - If EXT is plugged, EXT_PLUGGED will be set */
        if (!(flags & WIIPROTO_FLAG_MP_USED) &&
            wdata->state.exttype == WIIMOTE_EXT_NONE) {
                type = wiimote_cmd_read_ext(wdata, data);
                ret = type == wdata->state.exttype;

                spin_lock_irq(&wdata->state.lock);
                ret = ret && !(wdata->state.flags & WIIPROTO_FLAG_EXT_ACTIVE);
                ret = ret && !(wdata->state.flags & WIIPROTO_FLAG_MP_ACTIVE);
                ret = ret && !(wdata->state.flags & WIIPROTO_FLAG_EXT_PLUGGED);
                spin_unlock_irq(&wdata->state.lock);

                if (!ret)
                        hid_dbg(wdata->hdev, "state left: !EXT && !MP\n");

                /* poll MP for hotplug events */
                poll_mp = true;

                goto out_release;
        }

        /* The trickiest part is if both EXT and MP are active. We cannot read
         * the EXT ID, anymore, because MP is mapped over it. However, we use
         * a handy trick here:
         *   - EXT_ACTIVE is unset whenever !MP_PLUGGED is sent
         * MP_PLUGGED might be re-sent again before we are scheduled, but
         * EXT_ACTIVE will stay unset.
         * So it is enough to check for mp_mapped() and MP_ACTIVE and
         * EXT_ACTIVE. EXT_PLUGGED is a sanity check. */
        if (wdata->state.exttype != WIIMOTE_EXT_NONE &&
            wdata->state.mp > 0 && (flags & WIIPROTO_FLAG_MP_USED)) {
                type = wiimote_cmd_read_mp_mapped(wdata);
                ret = type != WIIMOTE_MP_NONE;
                ret = ret && type != WIIMOTE_MP_UNKNOWN;
                ret = ret && type != WIIMOTE_MP_SINGLE;

                spin_lock_irq(&wdata->state.lock);
                ret = ret && (wdata->state.flags & WIIPROTO_FLAG_EXT_PLUGGED);
                ret = ret && (wdata->state.flags & WIIPROTO_FLAG_EXT_ACTIVE);
                ret = ret && (wdata->state.flags & WIIPROTO_FLAG_MP_ACTIVE);
                spin_unlock_irq(&wdata->state.lock);

                if (!ret)
                        hid_dbg(wdata->hdev, "state left: EXT && MP\n");

                /* while MP is mapped, we get EXT_PLUGGED events */
                poll_mp = false;

                goto out_release;
        }

        /* unknown state */
        ret = false;

out_release:
        wiimote_cmd_release(wdata);

        /* only poll for MP if requested and if state didn't change */
        if (ret && poll_mp && !(flags & WIIPROTO_FLAG_BUILTIN_MP) &&
            !(flags & WIIPROTO_FLAG_NO_MP))
                wiimote_init_poll_mp(wdata);

        return ret;
}

static const char *wiimote_exttype_names[WIIMOTE_EXT_NUM] = {
        [WIIMOTE_EXT_NONE] = "None",
        [WIIMOTE_EXT_UNKNOWN] = "Unknown",
        [WIIMOTE_EXT_NUNCHUK] = "Nintendo Wii Nunchuk",
        [WIIMOTE_EXT_CLASSIC_CONTROLLER] = "Nintendo Wii Classic Controller",
        [WIIMOTE_EXT_BALANCE_BOARD] = "Nintendo Wii Balance Board",
        [WIIMOTE_EXT_PRO_CONTROLLER] = "Nintendo Wii U Pro Controller",
        [WIIMOTE_EXT_DRUMS] = "Nintendo Wii Drums",
        [WIIMOTE_EXT_GUITAR] = "Nintendo Wii Guitar",
};

/*
 * Handle hotplug events
 * If we receive an hotplug event and the device-check failed, we deinitialize
 * the extension ports, re-read all extension IDs and set the device into
 * the desired state. This involves mapping MP into the main extension
 * registers, setting up extension passthrough modes and initializing the
 * requested extensions.
 */
static void wiimote_init_hotplug(struct wiimote_data *wdata)
{
        __u8 exttype, extdata[6], mpdata[6];
        __u32 flags;
        bool mp;

        hid_dbg(wdata->hdev, "detect extensions..\n");

        wiimote_cmd_acquire_noint(wdata);

        spin_lock_irq(&wdata->state.lock);

        /* get state snapshot that we will then work on */
        flags = wdata->state.flags;

        /* disable event forwarding temporarily */
        wdata->state.flags &= ~WIIPROTO_FLAG_EXT_ACTIVE;
        wdata->state.flags &= ~WIIPROTO_FLAG_MP_ACTIVE;

        spin_unlock_irq(&wdata->state.lock);

        /* init extension and MP (deactivates current extension or MP) */
        wiimote_cmd_init_ext(wdata);
        if (flags & WIIPROTO_FLAG_NO_MP) {
                mp = false;
        } else {
                wiimote_cmd_init_mp(wdata);
                mp = wiimote_cmd_read_mp(wdata, mpdata);
        }
        exttype = wiimote_cmd_read_ext(wdata, extdata);

        wiimote_cmd_release(wdata);

        /* load/unload extension module if it changed */
        if (exttype != wdata->state.exttype) {
                /* unload previous extension */
                wiimote_ext_unload(wdata);

                if (exttype == WIIMOTE_EXT_UNKNOWN) {
                        hid_info(wdata->hdev, "cannot detect extension; %6phC\n",
                                 extdata);
                } else if (exttype == WIIMOTE_EXT_NONE) {
                        spin_lock_irq(&wdata->state.lock);
                        wdata->state.exttype = WIIMOTE_EXT_NONE;
                        spin_unlock_irq(&wdata->state.lock);
                } else {
                        hid_info(wdata->hdev, "detected extension: %s\n",
                                 wiimote_exttype_names[exttype]);
                        /* try loading new extension */
                        wiimote_ext_load(wdata, exttype);
                }
        }

        /* load/unload MP module if it changed */
        if (mp) {
                if (!wdata->state.mp) {
                        hid_info(wdata->hdev, "detected extension: Nintendo Wii Motion Plus\n");
                        wiimote_mp_load(wdata);
                }
        } else if (wdata->state.mp) {
                wiimote_mp_unload(wdata);
        }

        /* if MP is not used, do not map or activate it */
        if (!(flags & WIIPROTO_FLAG_MP_USED))
                mp = false;

        /* map MP into main extension registers if used */
        if (mp) {
                wiimote_cmd_acquire_noint(wdata);
                wiimote_cmd_map_mp(wdata, exttype);
                wiimote_cmd_release(wdata);

                /* delete MP hotplug timer */
                del_timer_sync(&wdata->timer);
        } else {
                /* reschedule MP hotplug timer */
                if (!(flags & WIIPROTO_FLAG_BUILTIN_MP) &&
                    !(flags & WIIPROTO_FLAG_NO_MP))
                        mod_timer(&wdata->timer, jiffies + HZ * 4);
        }

        spin_lock_irq(&wdata->state.lock);

        /* enable data forwarding again and set expected hotplug state */
        if (mp) {
                wdata->state.flags |= WIIPROTO_FLAG_MP_ACTIVE;
                if (wdata->state.exttype == WIIMOTE_EXT_NONE) {
                        wdata->state.flags &= ~WIIPROTO_FLAG_EXT_PLUGGED;
                        wdata->state.flags &= ~WIIPROTO_FLAG_MP_PLUGGED;
                } else {
                        wdata->state.flags &= ~WIIPROTO_FLAG_EXT_PLUGGED;
                        wdata->state.flags |= WIIPROTO_FLAG_MP_PLUGGED;
                        wdata->state.flags |= WIIPROTO_FLAG_EXT_ACTIVE;
                }
        } else if (wdata->state.exttype != WIIMOTE_EXT_NONE) {
                wdata->state.flags |= WIIPROTO_FLAG_EXT_ACTIVE;
        }

        /* request status report for hotplug state updates */
        wiiproto_req_status(wdata);

        spin_unlock_irq(&wdata->state.lock);

        hid_dbg(wdata->hdev, "detected extensions: MP: %d EXT: %d\n",
                wdata->state.mp, wdata->state.exttype);
}

static void wiimote_init_worker(struct work_struct *work)
{
        struct wiimote_data *wdata = container_of(work, struct wiimote_data,
                                                  init_worker);
        bool changed = false;

        if (wdata->state.devtype == WIIMOTE_DEV_PENDING) {
                wiimote_init_detect(wdata);
                changed = true;
        }

        if (changed || !wiimote_init_check(wdata))
                wiimote_init_hotplug(wdata);

        if (changed)
                kobject_uevent(&wdata->hdev->dev.kobj, KOBJ_CHANGE);
}

void __wiimote_schedule(struct wiimote_data *wdata)
{
        if (!(wdata->state.flags & WIIPROTO_FLAG_EXITING))
                schedule_work(&wdata->init_worker);
}

static void wiimote_schedule(struct wiimote_data *wdata)
{
        unsigned long flags;

        spin_lock_irqsave(&wdata->state.lock, flags);
        __wiimote_schedule(wdata);
        spin_unlock_irqrestore(&wdata->state.lock, flags);
}

static void wiimote_init_timeout(struct timer_list *t)
{
        struct wiimote_data *wdata = from_timer(wdata, t, timer);

        wiimote_schedule(wdata);
}

/* protocol handlers */

static void handler_keys(struct wiimote_data *wdata, const __u8 *payload)
{
        const __u8 *iter, *mods;
        const struct wiimod_ops *ops;

        ops = wiimod_ext_table[wdata->state.exttype];
        if (ops->in_keys) {
                ops->in_keys(wdata, payload);
                return;
        }

        mods = wiimote_devtype_mods[wdata->state.devtype];
        for (iter = mods; *iter != WIIMOD_NULL; ++iter) {
                ops = wiimod_table[*iter];
                if (ops->in_keys) {
                        ops->in_keys(wdata, payload);
                        break;
                }
        }
}

static void handler_accel(struct wiimote_data *wdata, const __u8 *payload)
{
        const __u8 *iter, *mods;
        const struct wiimod_ops *ops;

        ops = wiimod_ext_table[wdata->state.exttype];
        if (ops->in_accel) {
                ops->in_accel(wdata, payload);
                return;
        }

        mods = wiimote_devtype_mods[wdata->state.devtype];
        for (iter = mods; *iter != WIIMOD_NULL; ++iter) {
                ops = wiimod_table[*iter];
                if (ops->in_accel) {
                        ops->in_accel(wdata, payload);
                        break;
                }
        }
}

static bool valid_ext_handler(const struct wiimod_ops *ops, size_t len)
{
        if (!ops->in_ext)
                return false;
        if ((ops->flags & WIIMOD_FLAG_EXT8) && len < 8)
                return false;
        if ((ops->flags & WIIMOD_FLAG_EXT16) && len < 16)
                return false;

        return true;
}

static void handler_ext(struct wiimote_data *wdata, const __u8 *payload,
                        size_t len)
{
        static const __u8 invalid[21] = { 0xff, 0xff, 0xff, 0xff,
                                          0xff, 0xff, 0xff, 0xff,
                                          0xff, 0xff, 0xff, 0xff,
                                          0xff, 0xff, 0xff, 0xff,
                                          0xff, 0xff, 0xff, 0xff,
                                          0xff };
        const __u8 *iter, *mods;
        const struct wiimod_ops *ops;
        bool is_mp;

        if (len > 21)
                len = 21;
        if (len < 6 || !memcmp(payload, invalid, len))
                return;

        /* if MP is active, track MP slot hotplugging */
        if (wdata->state.flags & WIIPROTO_FLAG_MP_ACTIVE) {
                /* this bit is set for invalid events (eg. during hotplug) */
                if (payload[5] & 0x01)
                        return;

                if (payload[4] & 0x01) {
                        if (!(wdata->state.flags & WIIPROTO_FLAG_MP_PLUGGED)) {
                                hid_dbg(wdata->hdev, "MP hotplug: 1\n");
                                wdata->state.flags |= WIIPROTO_FLAG_MP_PLUGGED;
                                __wiimote_schedule(wdata);
                        }
                } else {
                        if (wdata->state.flags & WIIPROTO_FLAG_MP_PLUGGED) {
                                hid_dbg(wdata->hdev, "MP hotplug: 0\n");
                                wdata->state.flags &= ~WIIPROTO_FLAG_MP_PLUGGED;
                                wdata->state.flags &= ~WIIPROTO_FLAG_EXT_ACTIVE;
                                __wiimote_schedule(wdata);
                        }
                }

                /* detect MP data that is sent interleaved with EXT data */
                is_mp = payload[5] & 0x02;
        } else {
                is_mp = false;
        }

        /* ignore EXT events if no extension is active */
        if (!(wdata->state.flags & WIIPROTO_FLAG_EXT_ACTIVE) && !is_mp)
                return;

        /* try forwarding to extension handler, first */
        ops = wiimod_ext_table[wdata->state.exttype];
        if (is_mp && ops->in_mp) {
                ops->in_mp(wdata, payload);
                return;
        } else if (!is_mp && valid_ext_handler(ops, len)) {
                ops->in_ext(wdata, payload);
                return;
        }

        /* try forwarding to MP handler */
        ops = &wiimod_mp;
        if (is_mp && ops->in_mp) {
                ops->in_mp(wdata, payload);
                return;
        } else if (!is_mp && valid_ext_handler(ops, len)) {
                ops->in_ext(wdata, payload);
                return;
        }

        /* try forwarding to loaded modules */
        mods = wiimote_devtype_mods[wdata->state.devtype];
        for (iter = mods; *iter != WIIMOD_NULL; ++iter) {
                ops = wiimod_table[*iter];
                if (is_mp && ops->in_mp) {
                        ops->in_mp(wdata, payload);
                        return;
                } else if (!is_mp && valid_ext_handler(ops, len)) {
                        ops->in_ext(wdata, payload);
                        return;
                }
        }
}

#define ir_to_input0(wdata, ir, packed) handler_ir((wdata), (ir), (packed), 0)
#define ir_to_input1(wdata, ir, packed) handler_ir((wdata), (ir), (packed), 1)
#define ir_to_input2(wdata, ir, packed) handler_ir((wdata), (ir), (packed), 2)
#define ir_to_input3(wdata, ir, packed) handler_ir((wdata), (ir), (packed), 3)

static void handler_ir(struct wiimote_data *wdata, const __u8 *payload,
                       bool packed, unsigned int id)
{
        const __u8 *iter, *mods;
        const struct wiimod_ops *ops;

        ops = wiimod_ext_table[wdata->state.exttype];
        if (ops->in_ir) {
                ops->in_ir(wdata, payload, packed, id);
                return;
        }

        mods = wiimote_devtype_mods[wdata->state.devtype];
        for (iter = mods; *iter != WIIMOD_NULL; ++iter) {
                ops = wiimod_table[*iter];
                if (ops->in_ir) {
                        ops->in_ir(wdata, payload, packed, id);
                        break;
                }
        }
}

/* reduced status report with "BB BB" key data only */
static void handler_status_K(struct wiimote_data *wdata,
                             const __u8 *payload)
{
        handler_keys(wdata, payload);

        /* on status reports the drm is reset so we need to resend the drm */
        wiiproto_req_drm(wdata, WIIPROTO_REQ_NULL);
}

/* extended status report with "BB BB LF 00 00 VV" data */
static void handler_status(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_status_K(wdata, payload);

        /* update extension status */
        if (payload[2] & 0x02) {
                if (!(wdata->state.flags & WIIPROTO_FLAG_EXT_PLUGGED)) {
                        hid_dbg(wdata->hdev, "EXT hotplug: 1\n");
                        wdata->state.flags |= WIIPROTO_FLAG_EXT_PLUGGED;
                        __wiimote_schedule(wdata);
                }
        } else {
                if (wdata->state.flags & WIIPROTO_FLAG_EXT_PLUGGED) {
                        hid_dbg(wdata->hdev, "EXT hotplug: 0\n");
                        wdata->state.flags &= ~WIIPROTO_FLAG_EXT_PLUGGED;
                        wdata->state.flags &= ~WIIPROTO_FLAG_MP_PLUGGED;
                        wdata->state.flags &= ~WIIPROTO_FLAG_EXT_ACTIVE;
                        wdata->state.flags &= ~WIIPROTO_FLAG_MP_ACTIVE;
                        __wiimote_schedule(wdata);
                }
        }

        wdata->state.cmd_battery = payload[5];
        if (wiimote_cmd_pending(wdata, WIIPROTO_REQ_SREQ, 0))
                wiimote_cmd_complete(wdata);
}

/* reduced generic report with "BB BB" key data only */
static void handler_generic_K(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_keys(wdata, payload);
}

static void handler_data(struct wiimote_data *wdata, const __u8 *payload)
{
        __u16 offset = payload[3] << 8 | payload[4];
        __u8 size = (payload[2] >> 4) + 1;
        __u8 err = payload[2] & 0x0f;

        handler_keys(wdata, payload);

        if (wiimote_cmd_pending(wdata, WIIPROTO_REQ_RMEM, offset)) {
                if (err)
                        size = 0;
                else if (size > wdata->state.cmd_read_size)
                        size = wdata->state.cmd_read_size;

                wdata->state.cmd_read_size = size;
                if (wdata->state.cmd_read_buf)
                        memcpy(wdata->state.cmd_read_buf, &payload[5], size);
                wiimote_cmd_complete(wdata);
        }
}

static void handler_return(struct wiimote_data *wdata, const __u8 *payload)
{
        __u8 err = payload[3];
        __u8 cmd = payload[2];

        handler_keys(wdata, payload);

        if (wiimote_cmd_pending(wdata, cmd, 0)) {
                wdata->state.cmd_err = err;
                wiimote_cmd_complete(wdata);
        } else if (err) {
                hid_warn(wdata->hdev, "Remote error %hhu on req %hhu\n", err,
                                                                        cmd);
        }
}

static void handler_drm_KA(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_keys(wdata, payload);
        handler_accel(wdata, payload);
}

static void handler_drm_KE(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_keys(wdata, payload);
        handler_ext(wdata, &payload[2], 8);
}

static void handler_drm_KAI(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_keys(wdata, payload);
        handler_accel(wdata, payload);
        ir_to_input0(wdata, &payload[5], false);
        ir_to_input1(wdata, &payload[8], false);
        ir_to_input2(wdata, &payload[11], false);
        ir_to_input3(wdata, &payload[14], false);
}

static void handler_drm_KEE(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_keys(wdata, payload);
        handler_ext(wdata, &payload[2], 19);
}

static void handler_drm_KIE(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_keys(wdata, payload);
        ir_to_input0(wdata, &payload[2], false);
        ir_to_input1(wdata, &payload[4], true);
        ir_to_input2(wdata, &payload[7], false);
        ir_to_input3(wdata, &payload[9], true);
        handler_ext(wdata, &payload[12], 9);
}

static void handler_drm_KAE(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_keys(wdata, payload);
        handler_accel(wdata, payload);
        handler_ext(wdata, &payload[5], 16);
}

static void handler_drm_KAIE(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_keys(wdata, payload);
        handler_accel(wdata, payload);
        ir_to_input0(wdata, &payload[5], false);
        ir_to_input1(wdata, &payload[7], true);
        ir_to_input2(wdata, &payload[10], false);
        ir_to_input3(wdata, &payload[12], true);
        handler_ext(wdata, &payload[15], 6);
}

static void handler_drm_E(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_ext(wdata, payload, 21);
}

static void handler_drm_SKAI1(struct wiimote_data *wdata, const __u8 *payload)
{
        handler_keys(wdata, payload);

        wdata->state.accel_split[0] = payload[2];
        wdata->state.accel_split[1] = (payload[0] >> 1) & (0x10 | 0x20);
        wdata->state.accel_split[1] |= (payload[1] << 1) & (0x40 | 0x80);

        ir_to_input0(wdata, &payload[3], false);
        ir_to_input1(wdata, &payload[12], false);
}

static void handler_drm_SKAI2(struct wiimote_data *wdata, const __u8 *payload)
{
        __u8 buf[5];

        handler_keys(wdata, payload);

        wdata->state.accel_split[1] |= (payload[0] >> 5) & (0x01 | 0x02);
        wdata->state.accel_split[1] |= (payload[1] >> 3) & (0x04 | 0x08);

        buf[0] = 0;
        buf[1] = 0;
        buf[2] = wdata->state.accel_split[0];
        buf[3] = payload[2];
        buf[4] = wdata->state.accel_split[1];
        handler_accel(wdata, buf);

        ir_to_input2(wdata, &payload[3], false);
        ir_to_input3(wdata, &payload[12], false);
}

struct wiiproto_handler {
        __u8 id;
        size_t size;
        void (*func)(struct wiimote_data *wdata, const __u8 *payload);
};

static struct wiiproto_handler handlers[] = {
        { .id = WIIPROTO_REQ_STATUS, .size = 6, .func = handler_status },
        { .id = WIIPROTO_REQ_STATUS, .size = 2, .func = handler_status_K },
        { .id = WIIPROTO_REQ_DATA, .size = 21, .func = handler_data },
        { .id = WIIPROTO_REQ_DATA, .size = 2, .func = handler_generic_K },
        { .id = WIIPROTO_REQ_RETURN, .size = 4, .func = handler_return },
        { .id = WIIPROTO_REQ_RETURN, .size = 2, .func = handler_generic_K },
        { .id = WIIPROTO_REQ_DRM_K, .size = 2, .func = handler_keys },
        { .id = WIIPROTO_REQ_DRM_KA, .size = 5, .func = handler_drm_KA },
        { .id = WIIPROTO_REQ_DRM_KA, .size = 2, .func = handler_generic_K },
        { .id = WIIPROTO_REQ_DRM_KE, .size = 10, .func = handler_drm_KE },
        { .id = WIIPROTO_REQ_DRM_KE, .size = 2, .func = handler_generic_K },
        { .id = WIIPROTO_REQ_DRM_KAI, .size = 17, .func = handler_drm_KAI },
        { .id = WIIPROTO_REQ_DRM_KAI, .size = 2, .func = handler_generic_K },
        { .id = WIIPROTO_REQ_DRM_KEE, .size = 21, .func = handler_drm_KEE },
        { .id = WIIPROTO_REQ_DRM_KEE, .size = 2, .func = handler_generic_K },
        { .id = WIIPROTO_REQ_DRM_KAE, .size = 21, .func = handler_drm_KAE },
        { .id = WIIPROTO_REQ_DRM_KAE, .size = 2, .func = handler_generic_K },
        { .id = WIIPROTO_REQ_DRM_KIE, .size = 21, .func = handler_drm_KIE },
        { .id = WIIPROTO_REQ_DRM_KIE, .size = 2, .func = handler_generic_K },
        { .id = WIIPROTO_REQ_DRM_KAIE, .size = 21, .func = handler_drm_KAIE },
        { .id = WIIPROTO_REQ_DRM_KAIE, .size = 2, .func = handler_generic_K },
        { .id = WIIPROTO_REQ_DRM_E, .size = 21, .func = handler_drm_E },
        { .id = WIIPROTO_REQ_DRM_SKAI1, .size = 21, .func = handler_drm_SKAI1 },
        { .id = WIIPROTO_REQ_DRM_SKAI2, .size = 21, .func = handler_drm_SKAI2 },
        { .id = 0 }
};

static int wiimote_hid_event(struct hid_device *hdev, struct hid_report *report,
                                                        u8 *raw_data, int size)
{
        struct wiimote_data *wdata = hid_get_drvdata(hdev);
        struct wiiproto_handler *h;
        int i;
        unsigned long flags;

        if (size < 1)
                return -EINVAL;

        spin_lock_irqsave(&wdata->state.lock, flags);

        for (i = 0; handlers[i].id; ++i) {
                h = &handlers[i];
                if (h->id == raw_data[0] && h->size < size) {
                        h->func(wdata, &raw_data[1]);
                        break;
                }
        }

        if (!handlers[i].id)
                hid_warn(hdev, "Unhandled report %hhu size %d\n", raw_data[0],
                                                                        size);

        spin_unlock_irqrestore(&wdata->state.lock, flags);

        return 0;
}

static ssize_t wiimote_ext_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        struct wiimote_data *wdata = dev_to_wii(dev);
        __u8 type;
        unsigned long flags;

        spin_lock_irqsave(&wdata->state.lock, flags);
        type = wdata->state.exttype;
        spin_unlock_irqrestore(&wdata->state.lock, flags);

        switch (type) {
        case WIIMOTE_EXT_NONE:
                return sprintf(buf, "none\n");
        case WIIMOTE_EXT_NUNCHUK:
                return sprintf(buf, "nunchuk\n");
        case WIIMOTE_EXT_CLASSIC_CONTROLLER:
                return sprintf(buf, "classic\n");
        case WIIMOTE_EXT_BALANCE_BOARD:
                return sprintf(buf, "balanceboard\n");
        case WIIMOTE_EXT_PRO_CONTROLLER:
                return sprintf(buf, "procontroller\n");
        case WIIMOTE_EXT_DRUMS:
                return sprintf(buf, "drums\n");
        case WIIMOTE_EXT_GUITAR:
                return sprintf(buf, "guitar\n");
        case WIIMOTE_EXT_UNKNOWN:
                /* fallthrough */
        default:
                return sprintf(buf, "unknown\n");
        }
}

static ssize_t wiimote_ext_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
{
        struct wiimote_data *wdata = dev_to_wii(dev);

        if (!strcmp(buf, "scan")) {
                wiimote_schedule(wdata);
        } else {
                return -EINVAL;
        }

        return strnlen(buf, PAGE_SIZE);
}

static DEVICE_ATTR(extension, S_IRUGO | S_IWUSR | S_IWGRP, wiimote_ext_show,
                   wiimote_ext_store);

static ssize_t wiimote_dev_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        struct wiimote_data *wdata = dev_to_wii(dev);
        __u8 type;
        unsigned long flags;

        spin_lock_irqsave(&wdata->state.lock, flags);
        type = wdata->state.devtype;
        spin_unlock_irqrestore(&wdata->state.lock, flags);

        switch (type) {
        case WIIMOTE_DEV_GENERIC:
                return sprintf(buf, "generic\n");
        case WIIMOTE_DEV_GEN10:
                return sprintf(buf, "gen10\n");
        case WIIMOTE_DEV_GEN20:
                return sprintf(buf, "gen20\n");
        case WIIMOTE_DEV_BALANCE_BOARD:
                return sprintf(buf, "balanceboard\n");
        case WIIMOTE_DEV_PRO_CONTROLLER:
                return sprintf(buf, "procontroller\n");
        case WIIMOTE_DEV_PENDING:
                return sprintf(buf, "pending\n");
        case WIIMOTE_DEV_UNKNOWN:
                /* fallthrough */
        default:
                return sprintf(buf, "unknown\n");
        }
}

static DEVICE_ATTR(devtype, S_IRUGO, wiimote_dev_show, NULL);

static struct wiimote_data *wiimote_create(struct hid_device *hdev)
{
        struct wiimote_data *wdata;

        wdata = kzalloc(sizeof(*wdata), GFP_KERNEL);
        if (!wdata)
                return NULL;

        wdata->hdev = hdev;
        hid_set_drvdata(hdev, wdata);

        spin_lock_init(&wdata->queue.lock);
        INIT_WORK(&wdata->queue.worker, wiimote_queue_worker);

        spin_lock_init(&wdata->state.lock);
        init_completion(&wdata->state.ready);
        mutex_init(&wdata->state.sync);
        wdata->state.drm = WIIPROTO_REQ_DRM_K;
        wdata->state.cmd_battery = 0xff;

        INIT_WORK(&wdata->init_worker, wiimote_init_worker);
        timer_setup(&wdata->timer, wiimote_init_timeout, 0);

        return wdata;
}

static void wiimote_destroy(struct wiimote_data *wdata)
{
        unsigned long flags;

        wiidebug_deinit(wdata);

        /* prevent init_worker from being scheduled again */
        spin_lock_irqsave(&wdata->state.lock, flags);
        wdata->state.flags |= WIIPROTO_FLAG_EXITING;
        spin_unlock_irqrestore(&wdata->state.lock, flags);

        cancel_work_sync(&wdata->init_worker);
        del_timer_sync(&wdata->timer);

        device_remove_file(&wdata->hdev->dev, &dev_attr_devtype);
        device_remove_file(&wdata->hdev->dev, &dev_attr_extension);

        wiimote_mp_unload(wdata);
        wiimote_ext_unload(wdata);
        wiimote_modules_unload(wdata);
        cancel_work_sync(&wdata->queue.worker);
        hid_hw_close(wdata->hdev);
        hid_hw_stop(wdata->hdev);

        kfree(wdata);
}

static int wiimote_hid_probe(struct hid_device *hdev,
                                const struct hid_device_id *id)
{
        struct wiimote_data *wdata;
        int ret;

        hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;

        wdata = wiimote_create(hdev);
        if (!wdata) {
                hid_err(hdev, "Can't alloc device\n");
                return -ENOMEM;
        }

        ret = hid_parse(hdev);
        if (ret) {
                hid_err(hdev, "HID parse failed\n");
                goto err;
        }

        ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
        if (ret) {
                hid_err(hdev, "HW start failed\n");
                goto err;
        }

        ret = hid_hw_open(hdev);
        if (ret) {
                hid_err(hdev, "cannot start hardware I/O\n");
                goto err_stop;
        }

        ret = device_create_file(&hdev->dev, &dev_attr_extension);
        if (ret) {
                hid_err(hdev, "cannot create sysfs attribute\n");
                goto err_close;
        }

        ret = device_create_file(&hdev->dev, &dev_attr_devtype);
        if (ret) {
                hid_err(hdev, "cannot create sysfs attribute\n");
                goto err_ext;
        }

        ret = wiidebug_init(wdata);
        if (ret)
                goto err_free;

        hid_info(hdev, "New device registered\n");

        /* schedule device detection */
        wiimote_schedule(wdata);

        return 0;

err_free:
        wiimote_destroy(wdata);
        return ret;

err_ext:
        device_remove_file(&wdata->hdev->dev, &dev_attr_extension);
err_close:
        hid_hw_close(hdev);
err_stop:
        hid_hw_stop(hdev);
err:
        input_free_device(wdata->ir);
        input_free_device(wdata->accel);
        kfree(wdata);
        return ret;
}

static void wiimote_hid_remove(struct hid_device *hdev)
{
        struct wiimote_data *wdata = hid_get_drvdata(hdev);

        hid_info(hdev, "Device removed\n");
        wiimote_destroy(wdata);
}

static const struct hid_device_id wiimote_hid_devices[] = {
        { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_NINTENDO,
                                USB_DEVICE_ID_NINTENDO_WIIMOTE) },
        { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_NINTENDO,
                                USB_DEVICE_ID_NINTENDO_WIIMOTE2) },
        { }
};
MODULE_DEVICE_TABLE(hid, wiimote_hid_devices);

static struct hid_driver wiimote_hid_driver = {
        .name = "wiimote",
        .id_table = wiimote_hid_devices,
        .probe = wiimote_hid_probe,
        .remove = wiimote_hid_remove,
        .raw_event = wiimote_hid_event,
};
module_hid_driver(wiimote_hid_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
MODULE_DESCRIPTION("Driver for Nintendo Wii / Wii U peripherals");