linux/drivers/media/rc/ir-mce_kbd-decoder.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/* ir-mce_kbd-decoder.c - A decoder for the RC6-ish keyboard/mouse IR protocol
   3 * used by the Microsoft Remote Keyboard for Windows Media Center Edition,
   4 * referred to by Microsoft's Windows Media Center remote specification docs
   5 * as "an internal protocol called MCIR-2".
   6 *
   7 * Copyright (C) 2011 by Jarod Wilson <jarod@redhat.com>
   8 */
   9#include <linux/module.h>
  10
  11#include "rc-core-priv.h"
  12
  13/*
  14 * This decoder currently supports:
  15 * - MCIR-2 29-bit IR signals used for mouse movement and buttons
  16 * - MCIR-2 32-bit IR signals used for standard keyboard keys
  17 *
  18 * The media keys on the keyboard send RC-6 signals that are indistinguishable
  19 * from the keys of the same name on the stock MCE remote, and will be handled
  20 * by the standard RC-6 decoder, and be made available to the system via the
  21 * input device for the remote, rather than the keyboard/mouse one.
  22 */
  23
  24#define MCIR2_UNIT              333     /* us */
  25#define MCIR2_HEADER_NBITS      5
  26#define MCIR2_MOUSE_NBITS       29
  27#define MCIR2_KEYBOARD_NBITS    32
  28#define MCIR2_PREFIX_PULSE      (8 * MCIR2_UNIT)
  29#define MCIR2_PREFIX_SPACE      (1 * MCIR2_UNIT)
  30#define MCIR2_MAX_LEN           (3 * MCIR2_UNIT)
  31#define MCIR2_BIT_START         (1 * MCIR2_UNIT)
  32#define MCIR2_BIT_END           (1 * MCIR2_UNIT)
  33#define MCIR2_BIT_0             (1 * MCIR2_UNIT)
  34#define MCIR2_BIT_SET           (2 * MCIR2_UNIT)
  35#define MCIR2_MODE_MASK         0xf     /* for the header bits */
  36#define MCIR2_KEYBOARD_HEADER   0x4
  37#define MCIR2_MOUSE_HEADER      0x1
  38#define MCIR2_MASK_KEYS_START   0xe0
  39
  40enum mce_kbd_mode {
  41        MCIR2_MODE_KEYBOARD,
  42        MCIR2_MODE_MOUSE,
  43        MCIR2_MODE_UNKNOWN,
  44};
  45
  46enum mce_kbd_state {
  47        STATE_INACTIVE,
  48        STATE_HEADER_BIT_START,
  49        STATE_HEADER_BIT_END,
  50        STATE_BODY_BIT_START,
  51        STATE_BODY_BIT_END,
  52        STATE_FINISHED,
  53};
  54
  55static unsigned char kbd_keycodes[256] = {
  56        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_A,
  57        KEY_B,          KEY_C,          KEY_D,          KEY_E,          KEY_F,
  58        KEY_G,          KEY_H,          KEY_I,          KEY_J,          KEY_K,
  59        KEY_L,          KEY_M,          KEY_N,          KEY_O,          KEY_P,
  60        KEY_Q,          KEY_R,          KEY_S,          KEY_T,          KEY_U,
  61        KEY_V,          KEY_W,          KEY_X,          KEY_Y,          KEY_Z,
  62        KEY_1,          KEY_2,          KEY_3,          KEY_4,          KEY_5,
  63        KEY_6,          KEY_7,          KEY_8,          KEY_9,          KEY_0,
  64        KEY_ENTER,      KEY_ESC,        KEY_BACKSPACE,  KEY_TAB,        KEY_SPACE,
  65        KEY_MINUS,      KEY_EQUAL,      KEY_LEFTBRACE,  KEY_RIGHTBRACE, KEY_BACKSLASH,
  66        KEY_BACKSLASH,  KEY_SEMICOLON,  KEY_APOSTROPHE, KEY_GRAVE,      KEY_COMMA,
  67        KEY_DOT,        KEY_SLASH,      KEY_CAPSLOCK,   KEY_F1,         KEY_F2,
  68        KEY_F3,         KEY_F4,         KEY_F5,         KEY_F6,         KEY_F7,
  69        KEY_F8,         KEY_F9,         KEY_F10,        KEY_F11,        KEY_F12,
  70        KEY_SYSRQ,      KEY_SCROLLLOCK, KEY_PAUSE,      KEY_INSERT,     KEY_HOME,
  71        KEY_PAGEUP,     KEY_DELETE,     KEY_END,        KEY_PAGEDOWN,   KEY_RIGHT,
  72        KEY_LEFT,       KEY_DOWN,       KEY_UP,         KEY_NUMLOCK,    KEY_KPSLASH,
  73        KEY_KPASTERISK, KEY_KPMINUS,    KEY_KPPLUS,     KEY_KPENTER,    KEY_KP1,
  74        KEY_KP2,        KEY_KP3,        KEY_KP4,        KEY_KP5,        KEY_KP6,
  75        KEY_KP7,        KEY_KP8,        KEY_KP9,        KEY_KP0,        KEY_KPDOT,
  76        KEY_102ND,      KEY_COMPOSE,    KEY_POWER,      KEY_KPEQUAL,    KEY_F13,
  77        KEY_F14,        KEY_F15,        KEY_F16,        KEY_F17,        KEY_F18,
  78        KEY_F19,        KEY_F20,        KEY_F21,        KEY_F22,        KEY_F23,
  79        KEY_F24,        KEY_OPEN,       KEY_HELP,       KEY_PROPS,      KEY_FRONT,
  80        KEY_STOP,       KEY_AGAIN,      KEY_UNDO,       KEY_CUT,        KEY_COPY,
  81        KEY_PASTE,      KEY_FIND,       KEY_MUTE,       KEY_VOLUMEUP,   KEY_VOLUMEDOWN,
  82        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_KPCOMMA,    KEY_RESERVED,
  83        KEY_RO,         KEY_KATAKANAHIRAGANA, KEY_YEN,  KEY_HENKAN,     KEY_MUHENKAN,
  84        KEY_KPJPCOMMA,  KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_HANGUEL,
  85        KEY_HANJA,      KEY_KATAKANA,   KEY_HIRAGANA,   KEY_ZENKAKUHANKAKU, KEY_RESERVED,
  86        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  87        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  88        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  89        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  90        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  91        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  92        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  93        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  94        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  95        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  96        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  97        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  98        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  99        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
 100        KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_LEFTCTRL,
 101        KEY_LEFTSHIFT,  KEY_LEFTALT,    KEY_LEFTMETA,   KEY_RIGHTCTRL,  KEY_RIGHTSHIFT,
 102        KEY_RIGHTALT,   KEY_RIGHTMETA,  KEY_PLAYPAUSE,  KEY_STOPCD,     KEY_PREVIOUSSONG,
 103        KEY_NEXTSONG,   KEY_EJECTCD,    KEY_VOLUMEUP,   KEY_VOLUMEDOWN, KEY_MUTE,
 104        KEY_WWW,        KEY_BACK,       KEY_FORWARD,    KEY_STOP,       KEY_FIND,
 105        KEY_SCROLLUP,   KEY_SCROLLDOWN, KEY_EDIT,       KEY_SLEEP,      KEY_COFFEE,
 106        KEY_REFRESH,    KEY_CALC,       KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
 107        KEY_RESERVED
 108};
 109
 110static void mce_kbd_rx_timeout(struct timer_list *t)
 111{
 112        struct ir_raw_event_ctrl *raw = from_timer(raw, t, mce_kbd.rx_timeout);
 113        unsigned char maskcode;
 114        unsigned long flags;
 115        int i;
 116
 117        dev_dbg(&raw->dev->dev, "timer callback clearing all keys\n");
 118
 119        spin_lock_irqsave(&raw->mce_kbd.keylock, flags);
 120
 121        if (time_is_before_eq_jiffies(raw->mce_kbd.rx_timeout.expires)) {
 122                for (i = 0; i < 7; i++) {
 123                        maskcode = kbd_keycodes[MCIR2_MASK_KEYS_START + i];
 124                        input_report_key(raw->dev->input_dev, maskcode, 0);
 125                }
 126
 127                for (i = 0; i < MCIR2_MASK_KEYS_START; i++)
 128                        input_report_key(raw->dev->input_dev, kbd_keycodes[i],
 129                                         0);
 130
 131                input_sync(raw->dev->input_dev);
 132        }
 133        spin_unlock_irqrestore(&raw->mce_kbd.keylock, flags);
 134}
 135
 136static enum mce_kbd_mode mce_kbd_mode(struct mce_kbd_dec *data)
 137{
 138        switch (data->header & MCIR2_MODE_MASK) {
 139        case MCIR2_KEYBOARD_HEADER:
 140                return MCIR2_MODE_KEYBOARD;
 141        case MCIR2_MOUSE_HEADER:
 142                return MCIR2_MODE_MOUSE;
 143        default:
 144                return MCIR2_MODE_UNKNOWN;
 145        }
 146}
 147
 148static void ir_mce_kbd_process_keyboard_data(struct rc_dev *dev, u32 scancode)
 149{
 150        u8 keydata1  = (scancode >> 8) & 0xff;
 151        u8 keydata2  = (scancode >> 16) & 0xff;
 152        u8 shiftmask = scancode & 0xff;
 153        unsigned char maskcode;
 154        int i, keystate;
 155
 156        dev_dbg(&dev->dev, "keyboard: keydata2 = 0x%02x, keydata1 = 0x%02x, shiftmask = 0x%02x\n",
 157                keydata2, keydata1, shiftmask);
 158
 159        for (i = 0; i < 7; i++) {
 160                maskcode = kbd_keycodes[MCIR2_MASK_KEYS_START + i];
 161                if (shiftmask & (1 << i))
 162                        keystate = 1;
 163                else
 164                        keystate = 0;
 165                input_report_key(dev->input_dev, maskcode, keystate);
 166        }
 167
 168        if (keydata1)
 169                input_report_key(dev->input_dev, kbd_keycodes[keydata1], 1);
 170        if (keydata2)
 171                input_report_key(dev->input_dev, kbd_keycodes[keydata2], 1);
 172
 173        if (!keydata1 && !keydata2) {
 174                for (i = 0; i < MCIR2_MASK_KEYS_START; i++)
 175                        input_report_key(dev->input_dev, kbd_keycodes[i], 0);
 176        }
 177}
 178
 179static void ir_mce_kbd_process_mouse_data(struct rc_dev *dev, u32 scancode)
 180{
 181        /* raw mouse coordinates */
 182        u8 xdata = (scancode >> 7) & 0x7f;
 183        u8 ydata = (scancode >> 14) & 0x7f;
 184        int x, y;
 185        /* mouse buttons */
 186        bool right = scancode & 0x40;
 187        bool left  = scancode & 0x20;
 188
 189        if (xdata & 0x40)
 190                x = -((~xdata & 0x7f) + 1);
 191        else
 192                x = xdata;
 193
 194        if (ydata & 0x40)
 195                y = -((~ydata & 0x7f) + 1);
 196        else
 197                y = ydata;
 198
 199        dev_dbg(&dev->dev, "mouse: x = %d, y = %d, btns = %s%s\n",
 200                x, y, left ? "L" : "", right ? "R" : "");
 201
 202        input_report_rel(dev->input_dev, REL_X, x);
 203        input_report_rel(dev->input_dev, REL_Y, y);
 204
 205        input_report_key(dev->input_dev, BTN_LEFT, left);
 206        input_report_key(dev->input_dev, BTN_RIGHT, right);
 207}
 208
 209/**
 210 * ir_mce_kbd_decode() - Decode one mce_kbd pulse or space
 211 * @dev:        the struct rc_dev descriptor of the device
 212 * @ev:         the struct ir_raw_event descriptor of the pulse/space
 213 *
 214 * This function returns -EINVAL if the pulse violates the state machine
 215 */
 216static int ir_mce_kbd_decode(struct rc_dev *dev, struct ir_raw_event ev)
 217{
 218        struct mce_kbd_dec *data = &dev->raw->mce_kbd;
 219        u32 scancode;
 220        unsigned long delay;
 221        struct lirc_scancode lsc = {};
 222
 223        if (!is_timing_event(ev)) {
 224                if (ev.reset)
 225                        data->state = STATE_INACTIVE;
 226                return 0;
 227        }
 228
 229        if (!geq_margin(ev.duration, MCIR2_UNIT, MCIR2_UNIT / 2))
 230                goto out;
 231
 232again:
 233        dev_dbg(&dev->dev, "started at state %i (%uus %s)\n",
 234                data->state, ev.duration, TO_STR(ev.pulse));
 235
 236        if (!geq_margin(ev.duration, MCIR2_UNIT, MCIR2_UNIT / 2))
 237                return 0;
 238
 239        switch (data->state) {
 240
 241        case STATE_INACTIVE:
 242                if (!ev.pulse)
 243                        break;
 244
 245                /* Note: larger margin on first pulse since each MCIR2_UNIT
 246                   is quite short and some hardware takes some time to
 247                   adjust to the signal */
 248                if (!eq_margin(ev.duration, MCIR2_PREFIX_PULSE, MCIR2_UNIT))
 249                        break;
 250
 251                data->state = STATE_HEADER_BIT_START;
 252                data->count = 0;
 253                data->header = 0;
 254                return 0;
 255
 256        case STATE_HEADER_BIT_START:
 257                if (geq_margin(ev.duration, MCIR2_MAX_LEN, MCIR2_UNIT / 2))
 258                        break;
 259
 260                data->header <<= 1;
 261                if (ev.pulse)
 262                        data->header |= 1;
 263                data->count++;
 264                data->state = STATE_HEADER_BIT_END;
 265                return 0;
 266
 267        case STATE_HEADER_BIT_END:
 268                decrease_duration(&ev, MCIR2_BIT_END);
 269
 270                if (data->count != MCIR2_HEADER_NBITS) {
 271                        data->state = STATE_HEADER_BIT_START;
 272                        goto again;
 273                }
 274
 275                switch (mce_kbd_mode(data)) {
 276                case MCIR2_MODE_KEYBOARD:
 277                        data->wanted_bits = MCIR2_KEYBOARD_NBITS;
 278                        break;
 279                case MCIR2_MODE_MOUSE:
 280                        data->wanted_bits = MCIR2_MOUSE_NBITS;
 281                        break;
 282                default:
 283                        dev_dbg(&dev->dev, "not keyboard or mouse data\n");
 284                        goto out;
 285                }
 286
 287                data->count = 0;
 288                data->body = 0;
 289                data->state = STATE_BODY_BIT_START;
 290                goto again;
 291
 292        case STATE_BODY_BIT_START:
 293                if (geq_margin(ev.duration, MCIR2_MAX_LEN, MCIR2_UNIT / 2))
 294                        break;
 295
 296                data->body <<= 1;
 297                if (ev.pulse)
 298                        data->body |= 1;
 299                data->count++;
 300                data->state = STATE_BODY_BIT_END;
 301                return 0;
 302
 303        case STATE_BODY_BIT_END:
 304                if (data->count == data->wanted_bits)
 305                        data->state = STATE_FINISHED;
 306                else
 307                        data->state = STATE_BODY_BIT_START;
 308
 309                decrease_duration(&ev, MCIR2_BIT_END);
 310                goto again;
 311
 312        case STATE_FINISHED:
 313                if (ev.pulse)
 314                        break;
 315
 316                switch (data->wanted_bits) {
 317                case MCIR2_KEYBOARD_NBITS:
 318                        scancode = data->body & 0xffffff;
 319                        dev_dbg(&dev->dev, "keyboard data 0x%08x\n",
 320                                data->body);
 321                        spin_lock(&data->keylock);
 322                        if (scancode) {
 323                                delay = usecs_to_jiffies(dev->timeout) +
 324                                        msecs_to_jiffies(100);
 325                                mod_timer(&data->rx_timeout, jiffies + delay);
 326                        } else {
 327                                del_timer(&data->rx_timeout);
 328                        }
 329                        /* Pass data to keyboard buffer parser */
 330                        ir_mce_kbd_process_keyboard_data(dev, scancode);
 331                        spin_unlock(&data->keylock);
 332                        lsc.rc_proto = RC_PROTO_MCIR2_KBD;
 333                        break;
 334                case MCIR2_MOUSE_NBITS:
 335                        scancode = data->body & 0x1fffff;
 336                        dev_dbg(&dev->dev, "mouse data 0x%06x\n", scancode);
 337                        /* Pass data to mouse buffer parser */
 338                        ir_mce_kbd_process_mouse_data(dev, scancode);
 339                        lsc.rc_proto = RC_PROTO_MCIR2_MSE;
 340                        break;
 341                default:
 342                        dev_dbg(&dev->dev, "not keyboard or mouse data\n");
 343                        goto out;
 344                }
 345
 346                lsc.scancode = scancode;
 347                lirc_scancode_event(dev, &lsc);
 348                data->state = STATE_INACTIVE;
 349                input_event(dev->input_dev, EV_MSC, MSC_SCAN, scancode);
 350                input_sync(dev->input_dev);
 351                return 0;
 352        }
 353
 354out:
 355        dev_dbg(&dev->dev, "failed at state %i (%uus %s)\n",
 356                data->state, ev.duration, TO_STR(ev.pulse));
 357        data->state = STATE_INACTIVE;
 358        return -EINVAL;
 359}
 360
 361static int ir_mce_kbd_register(struct rc_dev *dev)
 362{
 363        struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
 364
 365        timer_setup(&mce_kbd->rx_timeout, mce_kbd_rx_timeout, 0);
 366        spin_lock_init(&mce_kbd->keylock);
 367
 368        return 0;
 369}
 370
 371static int ir_mce_kbd_unregister(struct rc_dev *dev)
 372{
 373        struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
 374
 375        del_timer_sync(&mce_kbd->rx_timeout);
 376
 377        return 0;
 378}
 379
 380static const struct ir_raw_timings_manchester ir_mce_kbd_timings = {
 381        .leader_pulse   = MCIR2_PREFIX_PULSE,
 382        .invert         = 1,
 383        .clock          = MCIR2_UNIT,
 384        .trailer_space  = MCIR2_UNIT * 10,
 385};
 386
 387/**
 388 * ir_mce_kbd_encode() - Encode a scancode as a stream of raw events
 389 *
 390 * @protocol:   protocol to encode
 391 * @scancode:   scancode to encode
 392 * @events:     array of raw ir events to write into
 393 * @max:        maximum size of @events
 394 *
 395 * Returns:     The number of events written.
 396 *              -ENOBUFS if there isn't enough space in the array to fit the
 397 *              encoding. In this case all @max events will have been written.
 398 */
 399static int ir_mce_kbd_encode(enum rc_proto protocol, u32 scancode,
 400                             struct ir_raw_event *events, unsigned int max)
 401{
 402        struct ir_raw_event *e = events;
 403        int len, ret;
 404        u64 raw;
 405
 406        if (protocol == RC_PROTO_MCIR2_KBD) {
 407                raw = scancode |
 408                      ((u64)MCIR2_KEYBOARD_HEADER << MCIR2_KEYBOARD_NBITS);
 409                len = MCIR2_KEYBOARD_NBITS + MCIR2_HEADER_NBITS;
 410        } else {
 411                raw = scancode |
 412                      ((u64)MCIR2_MOUSE_HEADER << MCIR2_MOUSE_NBITS);
 413                len = MCIR2_MOUSE_NBITS + MCIR2_HEADER_NBITS;
 414        }
 415
 416        ret = ir_raw_gen_manchester(&e, max, &ir_mce_kbd_timings, len, raw);
 417        if (ret < 0)
 418                return ret;
 419
 420        return e - events;
 421}
 422
 423static struct ir_raw_handler mce_kbd_handler = {
 424        .protocols      = RC_PROTO_BIT_MCIR2_KBD | RC_PROTO_BIT_MCIR2_MSE,
 425        .decode         = ir_mce_kbd_decode,
 426        .encode         = ir_mce_kbd_encode,
 427        .raw_register   = ir_mce_kbd_register,
 428        .raw_unregister = ir_mce_kbd_unregister,
 429        .carrier        = 36000,
 430        .min_timeout    = MCIR2_MAX_LEN + MCIR2_UNIT / 2,
 431};
 432
 433static int __init ir_mce_kbd_decode_init(void)
 434{
 435        ir_raw_handler_register(&mce_kbd_handler);
 436
 437        printk(KERN_INFO "IR MCE Keyboard/mouse protocol handler initialized\n");
 438        return 0;
 439}
 440
 441static void __exit ir_mce_kbd_decode_exit(void)
 442{
 443        ir_raw_handler_unregister(&mce_kbd_handler);
 444}
 445
 446module_init(ir_mce_kbd_decode_init);
 447module_exit(ir_mce_kbd_decode_exit);
 448
 449MODULE_LICENSE("GPL");
 450MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
 451MODULE_DESCRIPTION("MCE Keyboard/mouse IR protocol decoder");
 452