ir-mce_kbd-decoder.c

  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 = timer_container_of(raw, t,
113							   mce_kbd.rx_timeout);
114	unsigned char maskcode;
115	unsigned long flags;
116	int i;
117
118	dev_dbg(&raw->dev->dev, "timer callback clearing all keys\n");
119
120	spin_lock_irqsave(&raw->mce_kbd.keylock, flags);
121
122	if (time_is_before_eq_jiffies(raw->mce_kbd.rx_timeout.expires)) {
123		for (i = 0; i < 7; i++) {
124			maskcode = kbd_keycodes[MCIR2_MASK_KEYS_START + i];
125			input_report_key(raw->dev->input_dev, maskcode, 0);
126		}
127
128		for (i = 0; i < MCIR2_MASK_KEYS_START; i++)
129			input_report_key(raw->dev->input_dev, kbd_keycodes[i],
130					 0);
131
132		input_sync(raw->dev->input_dev);
133	}
134	spin_unlock_irqrestore(&raw->mce_kbd.keylock, flags);
135}
136
137static enum mce_kbd_mode mce_kbd_mode(struct mce_kbd_dec *data)
138{
139	switch (data->header & MCIR2_MODE_MASK) {
140	case MCIR2_KEYBOARD_HEADER:
141		return MCIR2_MODE_KEYBOARD;
142	case MCIR2_MOUSE_HEADER:
143		return MCIR2_MODE_MOUSE;
144	default:
145		return MCIR2_MODE_UNKNOWN;
146	}
147}
148
149static void ir_mce_kbd_process_keyboard_data(struct rc_dev *dev, u32 scancode)
150{
151	u8 keydata1  = (scancode >> 8) & 0xff;
152	u8 keydata2  = (scancode >> 16) & 0xff;
153	u8 shiftmask = scancode & 0xff;
154	unsigned char maskcode;
155	int i, keystate;
156
157	dev_dbg(&dev->dev, "keyboard: keydata2 = 0x%02x, keydata1 = 0x%02x, shiftmask = 0x%02x\n",
158		keydata2, keydata1, shiftmask);
159
160	for (i = 0; i < 7; i++) {
161		maskcode = kbd_keycodes[MCIR2_MASK_KEYS_START + i];
162		if (shiftmask & (1 << i))
163			keystate = 1;
164		else
165			keystate = 0;
166		input_report_key(dev->input_dev, maskcode, keystate);
167	}
168
169	if (keydata1)
170		input_report_key(dev->input_dev, kbd_keycodes[keydata1], 1);
171	if (keydata2)
172		input_report_key(dev->input_dev, kbd_keycodes[keydata2], 1);
173
174	if (!keydata1 && !keydata2) {
175		for (i = 0; i < MCIR2_MASK_KEYS_START; i++)
176			input_report_key(dev->input_dev, kbd_keycodes[i], 0);
177	}
178}
179
180static void ir_mce_kbd_process_mouse_data(struct rc_dev *dev, u32 scancode)
181{
182	/* raw mouse coordinates */
183	u8 xdata = (scancode >> 7) & 0x7f;
184	u8 ydata = (scancode >> 14) & 0x7f;
185	int x, y;
186	/* mouse buttons */
187	bool right = scancode & 0x40;
188	bool left  = scancode & 0x20;
189
190	if (xdata & 0x40)
191		x = -((~xdata & 0x7f) + 1);
192	else
193		x = xdata;
194
195	if (ydata & 0x40)
196		y = -((~ydata & 0x7f) + 1);
197	else
198		y = ydata;
199
200	dev_dbg(&dev->dev, "mouse: x = %d, y = %d, btns = %s%s\n",
201		x, y, left ? "L" : "", right ? "R" : "");
202
203	input_report_rel(dev->input_dev, REL_X, x);
204	input_report_rel(dev->input_dev, REL_Y, y);
205
206	input_report_key(dev->input_dev, BTN_LEFT, left);
207	input_report_key(dev->input_dev, BTN_RIGHT, right);
208}
209
210/**
211 * ir_mce_kbd_decode() - Decode one mce_kbd pulse or space
212 * @dev:	the struct rc_dev descriptor of the device
213 * @ev:		the struct ir_raw_event descriptor of the pulse/space
214 *
215 * This function returns -EINVAL if the pulse violates the state machine
216 */
217static int ir_mce_kbd_decode(struct rc_dev *dev, struct ir_raw_event ev)
218{
219	struct mce_kbd_dec *data = &dev->raw->mce_kbd;
220	u32 scancode;
221	unsigned long delay;
222	struct lirc_scancode lsc = {};
223
224	if (!is_timing_event(ev)) {
225		if (ev.overflow)
226			data->state = STATE_INACTIVE;
227		return 0;
228	}
229
230	if (!geq_margin(ev.duration, MCIR2_UNIT, MCIR2_UNIT / 2))
231		goto out;
232
233again:
234	dev_dbg(&dev->dev, "started at state %i (%uus %s)\n",
235		data->state, ev.duration, TO_STR(ev.pulse));
236
237	if (!geq_margin(ev.duration, MCIR2_UNIT, MCIR2_UNIT / 2))
238		return 0;
239
240	switch (data->state) {
241
242	case STATE_INACTIVE:
243		if (!ev.pulse)
244			break;
245
246		/* Note: larger margin on first pulse since each MCIR2_UNIT
247		   is quite short and some hardware takes some time to
248		   adjust to the signal */
249		if (!eq_margin(ev.duration, MCIR2_PREFIX_PULSE, MCIR2_UNIT))
250			break;
251
252		data->state = STATE_HEADER_BIT_START;
253		data->count = 0;
254		data->header = 0;
255		return 0;
256
257	case STATE_HEADER_BIT_START:
258		if (geq_margin(ev.duration, MCIR2_MAX_LEN, MCIR2_UNIT / 2))
259			break;
260
261		data->header <<= 1;
262		if (ev.pulse)
263			data->header |= 1;
264		data->count++;
265		data->state = STATE_HEADER_BIT_END;
266		return 0;
267
268	case STATE_HEADER_BIT_END:
269		decrease_duration(&ev, MCIR2_BIT_END);
270
271		if (data->count != MCIR2_HEADER_NBITS) {
272			data->state = STATE_HEADER_BIT_START;
273			goto again;
274		}
275
276		switch (mce_kbd_mode(data)) {
277		case MCIR2_MODE_KEYBOARD:
278			data->wanted_bits = MCIR2_KEYBOARD_NBITS;
279			break;
280		case MCIR2_MODE_MOUSE:
281			data->wanted_bits = MCIR2_MOUSE_NBITS;
282			break;
283		default:
284			dev_dbg(&dev->dev, "not keyboard or mouse data\n");
285			goto out;
286		}
287
288		data->count = 0;
289		data->body = 0;
290		data->state = STATE_BODY_BIT_START;
291		goto again;
292
293	case STATE_BODY_BIT_START:
294		if (geq_margin(ev.duration, MCIR2_MAX_LEN, MCIR2_UNIT / 2))
295			break;
296
297		data->body <<= 1;
298		if (ev.pulse)
299			data->body |= 1;
300		data->count++;
301		data->state = STATE_BODY_BIT_END;
302		return 0;
303
304	case STATE_BODY_BIT_END:
305		if (data->count == data->wanted_bits)
306			data->state = STATE_FINISHED;
307		else
308			data->state = STATE_BODY_BIT_START;
309
310		decrease_duration(&ev, MCIR2_BIT_END);
311		goto again;
312
313	case STATE_FINISHED:
314		if (ev.pulse)
315			break;
316
317		switch (data->wanted_bits) {
318		case MCIR2_KEYBOARD_NBITS:
319			scancode = data->body & 0xffffff;
320			dev_dbg(&dev->dev, "keyboard data 0x%08x\n",
321				data->body);
322			spin_lock(&data->keylock);
323			if (scancode) {
324				delay = usecs_to_jiffies(dev->timeout) +
325					msecs_to_jiffies(100);
326				mod_timer(&data->rx_timeout, jiffies + delay);
327			} else {
328				timer_delete(&data->rx_timeout);
329			}
330			/* Pass data to keyboard buffer parser */
331			ir_mce_kbd_process_keyboard_data(dev, scancode);
332			spin_unlock(&data->keylock);
333			lsc.rc_proto = RC_PROTO_MCIR2_KBD;
334			break;
335		case MCIR2_MOUSE_NBITS:
336			scancode = data->body & 0x1fffff;
337			dev_dbg(&dev->dev, "mouse data 0x%06x\n", scancode);
338			/* Pass data to mouse buffer parser */
339			ir_mce_kbd_process_mouse_data(dev, scancode);
340			lsc.rc_proto = RC_PROTO_MCIR2_MSE;
341			break;
342		default:
343			dev_dbg(&dev->dev, "not keyboard or mouse data\n");
344			goto out;
345		}
346
347		lsc.scancode = scancode;
348		lirc_scancode_event(dev, &lsc);
349		data->state = STATE_INACTIVE;
350		input_event(dev->input_dev, EV_MSC, MSC_SCAN, scancode);
351		input_sync(dev->input_dev);
352		return 0;
353	}
354
355out:
356	dev_dbg(&dev->dev, "failed at state %i (%uus %s)\n",
357		data->state, ev.duration, TO_STR(ev.pulse));
358	data->state = STATE_INACTIVE;
359	return -EINVAL;
360}
361
362static int ir_mce_kbd_register(struct rc_dev *dev)
363{
364	struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
365
366	timer_setup(&mce_kbd->rx_timeout, mce_kbd_rx_timeout, 0);
367	spin_lock_init(&mce_kbd->keylock);
368
369	return 0;
370}
371
372static int ir_mce_kbd_unregister(struct rc_dev *dev)
373{
374	struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
375
376	timer_delete_sync(&mce_kbd->rx_timeout);
377
378	return 0;
379}
380
381static const struct ir_raw_timings_manchester ir_mce_kbd_timings = {
382	.leader_pulse	= MCIR2_PREFIX_PULSE,
383	.invert		= 1,
384	.clock		= MCIR2_UNIT,
385	.trailer_space	= MCIR2_UNIT * 10,
386};
387
388/**
389 * ir_mce_kbd_encode() - Encode a scancode as a stream of raw events
390 *
391 * @protocol:   protocol to encode
392 * @scancode:   scancode to encode
393 * @events:     array of raw ir events to write into
394 * @max:        maximum size of @events
395 *
396 * Returns:     The number of events written.
397 *              -ENOBUFS if there isn't enough space in the array to fit the
398 *              encoding. In this case all @max events will have been written.
399 */
400static int ir_mce_kbd_encode(enum rc_proto protocol, u32 scancode,
401			     struct ir_raw_event *events, unsigned int max)
402{
403	struct ir_raw_event *e = events;
404	int len, ret;
405	u64 raw;
406
407	if (protocol == RC_PROTO_MCIR2_KBD) {
408		raw = scancode |
409		      ((u64)MCIR2_KEYBOARD_HEADER << MCIR2_KEYBOARD_NBITS);
410		len = MCIR2_KEYBOARD_NBITS + MCIR2_HEADER_NBITS;
411	} else {
412		raw = scancode |
413		      ((u64)MCIR2_MOUSE_HEADER << MCIR2_MOUSE_NBITS);
414		len = MCIR2_MOUSE_NBITS + MCIR2_HEADER_NBITS;
415	}
416
417	ret = ir_raw_gen_manchester(&e, max, &ir_mce_kbd_timings, len, raw);
418	if (ret < 0)
419		return ret;
420
421	return e - events;
422}
423
424static struct ir_raw_handler mce_kbd_handler = {
425	.protocols	= RC_PROTO_BIT_MCIR2_KBD | RC_PROTO_BIT_MCIR2_MSE,
426	.decode		= ir_mce_kbd_decode,
427	.encode		= ir_mce_kbd_encode,
428	.raw_register	= ir_mce_kbd_register,
429	.raw_unregister	= ir_mce_kbd_unregister,
430	.carrier	= 36000,
431	.min_timeout	= MCIR2_MAX_LEN + MCIR2_UNIT / 2,
432};
433
434static int __init ir_mce_kbd_decode_init(void)
435{
436	ir_raw_handler_register(&mce_kbd_handler);
437
438	printk(KERN_INFO "IR MCE Keyboard/mouse protocol handler initialized\n");
439	return 0;
440}
441
442static void __exit ir_mce_kbd_decode_exit(void)
443{
444	ir_raw_handler_unregister(&mce_kbd_handler);
445}
446
447module_init(ir_mce_kbd_decode_init);
448module_exit(ir_mce_kbd_decode_exit);
449
450MODULE_LICENSE("GPL");
451MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
452MODULE_DESCRIPTION("MCE Keyboard/mouse IR protocol decoder");