/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2020 Vladimir Kondratyev <wulf@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _HIDMAP_H_
#define _HIDMAP_H_

#include <sys/param.h>

#include <dev/hid/hid.h>

#define HIDMAP_MAX_MAPS 4

struct hid_device_id;
struct hidmap_hid_item;
struct hidmap_item;
struct hidmap;

enum hidmap_cb_state {
        HIDMAP_CB_IS_PROBING,
        HIDMAP_CB_IS_ATTACHING,
        HIDMAP_CB_IS_RUNNING,
        HIDMAP_CB_IS_DETACHING,
};

#define HIDMAP_KEY_NULL 0xFF    /* Special event code to discard input */

/* Third parameter of hidmap callback has different type depending on state */
union hidmap_cb_ctx {
        struct hid_item *hi;    /* Probe- and attach-stage callbacks */
        int32_t         data;   /* Run-stage callbacks */
        uint8_t         rid;    /* Run-stage finalizing callbacks */
};

#define HIDMAP_CB_ARGS                                                  \
        struct hidmap *hm, struct hidmap_hid_item *hi, union hidmap_cb_ctx ctx
typedef int hidmap_cb_t(HIDMAP_CB_ARGS);

/* These helpers can be used at any stage of any callbacks */
#define HIDMAP_CB_GET_STATE(...)                                        \
        ((hm == NULL) ? HIDMAP_CB_IS_PROBING : hm->cb_state)
#define HIDMAP_CB_GET_DEV(...)                                          \
        (hm == NULL ? NULL : hm->dev)
#define HIDMAP_CB_GET_SOFTC(...)                                        \
        (hm == NULL ? NULL : device_get_softc(hm->dev))
#define HIDMAP_CB_GET_EVDEV(...)                                        \
        (hm == NULL ? NULL : hm->evdev)
#define HIDMAP_CB_UDATA         (hi->udata)
#define HIDMAP_CB_UDATA64       (hi->udata64)
/* Special helpers for run-stage of finalizing callbacks */
#define HIDMAP_CB_GET_RID(...)  (ctx.rid)
#define HIDMAP_CB_GET_DATA(loc)                                         \
        hid_get_data(hm->intr_buf, hm->intr_len, (loc))
#define HIDMAP_CB_GET_UDATA(loc)                                        \
        hid_get_udata(hm->intr_buf, hm->intr_len, (loc))

enum hidmap_relabs {
        HIDMAP_RELABS_ANY = 0,
        HIDMAP_RELATIVE,
        HIDMAP_ABSOLUTE,
};

struct hidmap_item {
        union {
                struct {
                        uint16_t        type;   /* Evdev event type */
                        uint16_t        code;   /* Evdev event code */
                        uint16_t        fuzz;   /* Evdev event fuzz */
                        uint16_t        flat;   /* Evdev event flat */
                };
                hidmap_cb_t             *cb;    /* Reporting callback */
        };
        int32_t                 usage;          /* HID usage (base) */
        uint16_t                nusages;        /* number of usages */
        bool                    required:1;     /* Required by driver */
        enum hidmap_relabs      relabs:2;
        bool                    has_cb:1;
        bool                    final_cb:1;
        bool                    invert_value:1;
        bool                    forbidden:1;    /* Forbidden by driver */
        u_int                   reserved:9;
};

#define HIDMAP_ANY(_page, _usage, _type, _code)                         \
        .usage = HID_USAGE2((_page), (_usage)),                         \
        .nusages = 1,                                                   \
        .type = (_type),                                                \
        .code = (_code)
#define HIDMAP_ANY_RANGE(_page, _usage_from, _usage_to, _type, _code)   \
        .usage = HID_USAGE2((_page), (_usage_from)),                    \
        .nusages = (_usage_to) - (_usage_from) + 1,                     \
        .type = (_type),                                                \
        .code = (_code)
#define HIDMAP_ANY_CB(_page, _usage, _callback)                         \
        .usage = HID_USAGE2((_page), (_usage)),                         \
        .nusages = 1,                                                   \
        .cb = (_callback),                                              \
        .has_cb = true
#define HIDMAP_ANY_CB_RANGE(_page, _usage_from, _usage_to, _callback)   \
        .usage = HID_USAGE2((_page), (_usage_from)),                    \
        .nusages = (_usage_to) - (_usage_from) + 1,                     \
        .cb = (_callback),                                              \
        .has_cb = true
#define HIDMAP_KEY(_page, _usage, _code)                                \
        HIDMAP_ANY((_page), (_usage), EV_KEY, (_code)),                 \
                .relabs = HIDMAP_RELABS_ANY
#define HIDMAP_KEY_RANGE(_page, _ufrom, _uto, _code)                    \
        HIDMAP_ANY_RANGE((_page), (_ufrom), (_uto), EV_KEY, (_code)),   \
                .relabs = HIDMAP_RELABS_ANY
#define HIDMAP_REL(_page, _usage, _code)                                \
        HIDMAP_ANY((_page), (_usage), EV_REL, (_code)),                 \
                .relabs = HIDMAP_RELATIVE
#define HIDMAP_ABS(_page, _usage, _code)                                \
        HIDMAP_ANY((_page), (_usage), EV_ABS, (_code)),                 \
                .relabs = HIDMAP_ABSOLUTE
#define HIDMAP_SW(_page, _usage, _code)                                 \
        HIDMAP_ANY((_page), (_usage), EV_SW, (_code)),                  \
                .relabs = HIDMAP_RELABS_ANY
#define HIDMAP_REL_CB(_page, _usage, _callback)                         \
        HIDMAP_ANY_CB((_page), (_usage), (_callback)),                  \
                .relabs = HIDMAP_RELATIVE
#define HIDMAP_ABS_CB(_page, _usage, _callback)                         \
        HIDMAP_ANY_CB((_page), (_usage), (_callback)),                  \
                .relabs = HIDMAP_ABSOLUTE
/*
 * Special callback function which is not tied to particular HID input usage
 * but called at the end evdev properties setting or interrupt handler
 * just before evdev_register() or evdev_sync() calls.
 */
#define HIDMAP_FINAL_CB(_callback)                                      \
        HIDMAP_ANY_CB(0, 0, (_callback)), .final_cb = true

enum hidmap_type {
        HIDMAP_TYPE_FINALCB = 0,/* No HID item associated. Runs unconditionally
                                 * at the end of other items processing */
        HIDMAP_TYPE_CALLBACK,   /* HID item is reported with user callback */
        HIDMAP_TYPE_VARIABLE,   /* HID item is variable (single usage) */
        HIDMAP_TYPE_VAR_NULLST, /* HID item is null state variable */
        HIDMAP_TYPE_ARR_LIST,   /* HID item is array with list of usages */
        HIDMAP_TYPE_ARR_RANGE,  /* Array with range (min;max) of usages */
};

struct hidmap_hid_item {
        union {
                hidmap_cb_t     *cb;            /* Callback */
                struct {                        /* Variable */
                        uint16_t        evtype; /* Evdev event type */
                        uint16_t        code;   /* Evdev event code */
                };
                uint16_t        *codes;         /* Array list map type */
                int32_t         umin;           /* Array range map type */
        };
        union {
                void            *udata;         /* Callback private context */
                uint64_t        udata64;
                int32_t         last_val;       /* Last reported value (var) */
                uint16_t        last_key;       /* Last reported key (array) */
        };
        struct hid_location     loc;            /* HID item location */
        int32_t                 lmin;           /* HID item logical minimum */
        int32_t                 lmax;           /* HID item logical maximum */
        enum hidmap_type        type:8;
        uint8_t                 id;             /* Report ID */
        bool                    invert_value;
};

struct hidmap {
        device_t                dev;

        struct evdev_dev        *evdev;
        struct evdev_methods    evdev_methods;

        /* Scatter-gather list of maps */
        int                     nmaps;
        uint32_t                nmap_items[HIDMAP_MAX_MAPS];
        const struct hidmap_item        *map[HIDMAP_MAX_MAPS];

        /* List of preparsed HID items */
        uint32_t                nhid_items;
        struct hidmap_hid_item  *hid_items;

        /* Key event merging buffers */
        uint8_t                 *key_press;
        uint8_t                 *key_rel;
        uint16_t                key_min;
        uint16_t                key_max;

        int                     *debug_var;
        int                     debug_level;
        enum hidmap_cb_state    cb_state;
        void *                  intr_buf;
        hid_size_t              intr_len;
};

typedef uint8_t *               hidmap_caps_t;
#define HIDMAP_CAPS_SZ(nitems)  howmany((nitems), 8)
#define HIDMAP_CAPS(name, map)  uint8_t (name)[HIDMAP_CAPS_SZ(nitems(map))]
static inline bool
hidmap_test_cap(hidmap_caps_t caps, int cap)
{
        return (isset(caps, cap) != 0);
}

/*
 * It is safe to call any of following procedures in device_probe context
 * that makes possible to write probe-only drivers with attach/detach handlers
 * inherited from hidmap. See hcons and hsctrl drivers for example.
 */
static inline void
hidmap_set_dev(struct hidmap *hm, device_t dev)
{
        hm->dev = dev;
}

/* Hack to avoid #ifdef-ing of hidmap_set_debug_var in hidmap based drivers */
#ifdef HID_DEBUG
#define hidmap_set_debug_var(h, d)      _hidmap_set_debug_var((h), (d))
#else
#define hidmap_set_debug_var(...)
#endif
void    _hidmap_set_debug_var(struct hidmap *hm, int *debug_var);
#define HIDMAP_ADD_MAP(hm, map, caps)                                   \
        hidmap_add_map((hm), (map), nitems(map), (caps))
uint32_t hidmap_add_map(struct hidmap *hm, const struct hidmap_item *map,
            int nitems_map, hidmap_caps_t caps);

/* Versions of evdev_* functions capable to merge key events with same codes */
void    hidmap_support_key(struct hidmap *hm, uint16_t key);
void    hidmap_push_key(struct hidmap *hm, uint16_t key, int32_t value);

void    hidmap_intr(void *context, void *buf, hid_size_t len);
#define HIDMAP_PROBE(hm, dev, id, map, suffix)                          \
        hidmap_probe((hm), (dev), (id), nitems(id), (map), nitems(map), \
            (suffix), NULL)
int     hidmap_probe(struct hidmap* hm, device_t dev,
            const struct hid_device_id *id, int nitems_id,
            const struct hidmap_item *map, int nitems_map,
            const char *suffix, hidmap_caps_t caps);
int     hidmap_attach(struct hidmap *hm);
int     hidmap_detach(struct hidmap *hm);

#endif  /* _HIDMAP_H_ */