1 /* ir-mce_kbd-decoder.c - A decoder for the RC6-ish keyboard/mouse IR protocol
2  * used by the Microsoft Remote Keyboard for Windows Media Center Edition,
3  * referred to by Microsoft's Windows Media Center remote specification docs
4  * as "an internal protocol called MCIR-2".
5  *
6  * Copyright (C) 2011 by Jarod Wilson <jarod@redhat.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation version 2 of the License.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  */
17 #include <linux/module.h>
18 
19 #include "rc-core-priv.h"
20 
21 /*
22  * This decoder currently supports:
23  * - MCIR-2 29-bit IR signals used for mouse movement and buttons
24  * - MCIR-2 32-bit IR signals used for standard keyboard keys
25  *
26  * The media keys on the keyboard send RC-6 signals that are indistinguishable
27  * from the keys of the same name on the stock MCE remote, and will be handled
28  * by the standard RC-6 decoder, and be made available to the system via the
29  * input device for the remote, rather than the keyboard/mouse one.
30  */
31 
32 #define MCIR2_UNIT		333333	/* ns */
33 #define MCIR2_HEADER_NBITS	5
34 #define MCIR2_MOUSE_NBITS	29
35 #define MCIR2_KEYBOARD_NBITS	32
36 #define MCIR2_PREFIX_PULSE	(8 * MCIR2_UNIT)
37 #define MCIR2_PREFIX_SPACE	(1 * MCIR2_UNIT)
38 #define MCIR2_MAX_LEN		(3 * MCIR2_UNIT)
39 #define MCIR2_BIT_START		(1 * MCIR2_UNIT)
40 #define MCIR2_BIT_END		(1 * MCIR2_UNIT)
41 #define MCIR2_BIT_0		(1 * MCIR2_UNIT)
42 #define MCIR2_BIT_SET		(2 * MCIR2_UNIT)
43 #define MCIR2_MODE_MASK		0xf	/* for the header bits */
44 #define MCIR2_KEYBOARD_HEADER	0x4
45 #define MCIR2_MOUSE_HEADER	0x1
46 #define MCIR2_MASK_KEYS_START	0xe0
47 
48 enum mce_kbd_mode {
49 	MCIR2_MODE_KEYBOARD,
50 	MCIR2_MODE_MOUSE,
51 	MCIR2_MODE_UNKNOWN,
52 };
53 
54 enum mce_kbd_state {
55 	STATE_INACTIVE,
56 	STATE_HEADER_BIT_START,
57 	STATE_HEADER_BIT_END,
58 	STATE_BODY_BIT_START,
59 	STATE_BODY_BIT_END,
60 	STATE_FINISHED,
61 };
62 
63 static unsigned char kbd_keycodes[256] = {
64 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_A,
65 	KEY_B,		KEY_C,		KEY_D,		KEY_E,		KEY_F,
66 	KEY_G,		KEY_H,		KEY_I,		KEY_J,		KEY_K,
67 	KEY_L,		KEY_M,		KEY_N,		KEY_O,		KEY_P,
68 	KEY_Q,		KEY_R,		KEY_S,		KEY_T,		KEY_U,
69 	KEY_V,		KEY_W,		KEY_X,		KEY_Y,		KEY_Z,
70 	KEY_1,		KEY_2,		KEY_3,		KEY_4,		KEY_5,
71 	KEY_6,		KEY_7,		KEY_8,		KEY_9,		KEY_0,
72 	KEY_ENTER,	KEY_ESC,	KEY_BACKSPACE,	KEY_TAB,	KEY_SPACE,
73 	KEY_MINUS,	KEY_EQUAL,	KEY_LEFTBRACE,	KEY_RIGHTBRACE,	KEY_BACKSLASH,
74 	KEY_BACKSLASH,	KEY_SEMICOLON,	KEY_APOSTROPHE,	KEY_GRAVE,	KEY_COMMA,
75 	KEY_DOT,	KEY_SLASH,	KEY_CAPSLOCK,	KEY_F1,		KEY_F2,
76 	KEY_F3,		KEY_F4,		KEY_F5,		KEY_F6,		KEY_F7,
77 	KEY_F8,		KEY_F9,		KEY_F10,	KEY_F11,	KEY_F12,
78 	KEY_SYSRQ,	KEY_SCROLLLOCK,	KEY_PAUSE,	KEY_INSERT,	KEY_HOME,
79 	KEY_PAGEUP,	KEY_DELETE,	KEY_END,	KEY_PAGEDOWN,	KEY_RIGHT,
80 	KEY_LEFT,	KEY_DOWN,	KEY_UP,		KEY_NUMLOCK,	KEY_KPSLASH,
81 	KEY_KPASTERISK,	KEY_KPMINUS,	KEY_KPPLUS,	KEY_KPENTER,	KEY_KP1,
82 	KEY_KP2,	KEY_KP3,	KEY_KP4,	KEY_KP5,	KEY_KP6,
83 	KEY_KP7,	KEY_KP8,	KEY_KP9,	KEY_KP0,	KEY_KPDOT,
84 	KEY_102ND,	KEY_COMPOSE,	KEY_POWER,	KEY_KPEQUAL,	KEY_F13,
85 	KEY_F14,	KEY_F15,	KEY_F16,	KEY_F17,	KEY_F18,
86 	KEY_F19,	KEY_F20,	KEY_F21,	KEY_F22,	KEY_F23,
87 	KEY_F24,	KEY_OPEN,	KEY_HELP,	KEY_PROPS,	KEY_FRONT,
88 	KEY_STOP,	KEY_AGAIN,	KEY_UNDO,	KEY_CUT,	KEY_COPY,
89 	KEY_PASTE,	KEY_FIND,	KEY_MUTE,	KEY_VOLUMEUP,	KEY_VOLUMEDOWN,
90 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_KPCOMMA,	KEY_RESERVED,
91 	KEY_RO,		KEY_KATAKANAHIRAGANA, KEY_YEN,	KEY_HENKAN,	KEY_MUHENKAN,
92 	KEY_KPJPCOMMA,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_HANGUEL,
93 	KEY_HANJA,	KEY_KATAKANA,	KEY_HIRAGANA,	KEY_ZENKAKUHANKAKU, 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_RESERVED,
101 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,
102 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,
103 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,
104 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,
105 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,
106 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,
107 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,
108 	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,	KEY_LEFTCTRL,
109 	KEY_LEFTSHIFT,	KEY_LEFTALT,	KEY_LEFTMETA,	KEY_RIGHTCTRL,	KEY_RIGHTSHIFT,
110 	KEY_RIGHTALT,	KEY_RIGHTMETA,	KEY_PLAYPAUSE,	KEY_STOPCD,	KEY_PREVIOUSSONG,
111 	KEY_NEXTSONG,	KEY_EJECTCD,	KEY_VOLUMEUP,	KEY_VOLUMEDOWN,	KEY_MUTE,
112 	KEY_WWW,	KEY_BACK,	KEY_FORWARD,	KEY_STOP,	KEY_FIND,
113 	KEY_SCROLLUP,	KEY_SCROLLDOWN,	KEY_EDIT,	KEY_SLEEP,	KEY_COFFEE,
114 	KEY_REFRESH,	KEY_CALC,	KEY_RESERVED,	KEY_RESERVED,	KEY_RESERVED,
115 	KEY_RESERVED
116 };
117 
118 static void mce_kbd_rx_timeout(struct timer_list *t)
119 {
120 	struct ir_raw_event_ctrl *raw = from_timer(raw, t, mce_kbd.rx_timeout);
121 	unsigned char maskcode;
122 	unsigned long flags;
123 	int i;
124 
125 	dev_dbg(&raw->dev->dev, "timer callback clearing all keys\n");
126 
127 	spin_lock_irqsave(&raw->mce_kbd.keylock, flags);
128 
129 	if (time_is_before_eq_jiffies(raw->mce_kbd.rx_timeout.expires)) {
130 		for (i = 0; i < 7; i++) {
131 			maskcode = kbd_keycodes[MCIR2_MASK_KEYS_START + i];
132 			input_report_key(raw->dev->input_dev, maskcode, 0);
133 		}
134 
135 		for (i = 0; i < MCIR2_MASK_KEYS_START; i++)
136 			input_report_key(raw->dev->input_dev, kbd_keycodes[i],
137 					 0);
138 
139 		input_sync(raw->dev->input_dev);
140 	}
141 	spin_unlock_irqrestore(&raw->mce_kbd.keylock, flags);
142 }
143 
144 static enum mce_kbd_mode mce_kbd_mode(struct mce_kbd_dec *data)
145 {
146 	switch (data->header & MCIR2_MODE_MASK) {
147 	case MCIR2_KEYBOARD_HEADER:
148 		return MCIR2_MODE_KEYBOARD;
149 	case MCIR2_MOUSE_HEADER:
150 		return MCIR2_MODE_MOUSE;
151 	default:
152 		return MCIR2_MODE_UNKNOWN;
153 	}
154 }
155 
156 static void ir_mce_kbd_process_keyboard_data(struct rc_dev *dev, u32 scancode)
157 {
158 	u8 keydata1  = (scancode >> 8) & 0xff;
159 	u8 keydata2  = (scancode >> 16) & 0xff;
160 	u8 shiftmask = scancode & 0xff;
161 	unsigned char maskcode;
162 	int i, keystate;
163 
164 	dev_dbg(&dev->dev, "keyboard: keydata2 = 0x%02x, keydata1 = 0x%02x, shiftmask = 0x%02x\n",
165 		keydata2, keydata1, shiftmask);
166 
167 	for (i = 0; i < 7; i++) {
168 		maskcode = kbd_keycodes[MCIR2_MASK_KEYS_START + i];
169 		if (shiftmask & (1 << i))
170 			keystate = 1;
171 		else
172 			keystate = 0;
173 		input_report_key(dev->input_dev, maskcode, keystate);
174 	}
175 
176 	if (keydata1)
177 		input_report_key(dev->input_dev, kbd_keycodes[keydata1], 1);
178 	if (keydata2)
179 		input_report_key(dev->input_dev, kbd_keycodes[keydata2], 1);
180 
181 	if (!keydata1 && !keydata2) {
182 		for (i = 0; i < MCIR2_MASK_KEYS_START; i++)
183 			input_report_key(dev->input_dev, kbd_keycodes[i], 0);
184 	}
185 }
186 
187 static void ir_mce_kbd_process_mouse_data(struct rc_dev *dev, u32 scancode)
188 {
189 	/* raw mouse coordinates */
190 	u8 xdata = (scancode >> 7) & 0x7f;
191 	u8 ydata = (scancode >> 14) & 0x7f;
192 	int x, y;
193 	/* mouse buttons */
194 	bool right = scancode & 0x40;
195 	bool left  = scancode & 0x20;
196 
197 	if (xdata & 0x40)
198 		x = -((~xdata & 0x7f) + 1);
199 	else
200 		x = xdata;
201 
202 	if (ydata & 0x40)
203 		y = -((~ydata & 0x7f) + 1);
204 	else
205 		y = ydata;
206 
207 	dev_dbg(&dev->dev, "mouse: x = %d, y = %d, btns = %s%s\n",
208 		x, y, left ? "L" : "", right ? "R" : "");
209 
210 	input_report_rel(dev->input_dev, REL_X, x);
211 	input_report_rel(dev->input_dev, REL_Y, y);
212 
213 	input_report_key(dev->input_dev, BTN_LEFT, left);
214 	input_report_key(dev->input_dev, BTN_RIGHT, right);
215 }
216 
217 /**
218  * ir_mce_kbd_decode() - Decode one mce_kbd pulse or space
219  * @dev:	the struct rc_dev descriptor of the device
220  * @ev:		the struct ir_raw_event descriptor of the pulse/space
221  *
222  * This function returns -EINVAL if the pulse violates the state machine
223  */
224 static int ir_mce_kbd_decode(struct rc_dev *dev, struct ir_raw_event ev)
225 {
226 	struct mce_kbd_dec *data = &dev->raw->mce_kbd;
227 	u32 scancode;
228 	unsigned long delay;
229 	struct lirc_scancode lsc = {};
230 
231 	if (!is_timing_event(ev)) {
232 		if (ev.reset)
233 			data->state = STATE_INACTIVE;
234 		return 0;
235 	}
236 
237 	if (!geq_margin(ev.duration, MCIR2_UNIT, MCIR2_UNIT / 2))
238 		goto out;
239 
240 again:
241 	dev_dbg(&dev->dev, "started at state %i (%uus %s)\n",
242 		data->state, TO_US(ev.duration), TO_STR(ev.pulse));
243 
244 	if (!geq_margin(ev.duration, MCIR2_UNIT, MCIR2_UNIT / 2))
245 		return 0;
246 
247 	switch (data->state) {
248 
249 	case STATE_INACTIVE:
250 		if (!ev.pulse)
251 			break;
252 
253 		/* Note: larger margin on first pulse since each MCIR2_UNIT
254 		   is quite short and some hardware takes some time to
255 		   adjust to the signal */
256 		if (!eq_margin(ev.duration, MCIR2_PREFIX_PULSE, MCIR2_UNIT))
257 			break;
258 
259 		data->state = STATE_HEADER_BIT_START;
260 		data->count = 0;
261 		data->header = 0;
262 		return 0;
263 
264 	case STATE_HEADER_BIT_START:
265 		if (geq_margin(ev.duration, MCIR2_MAX_LEN, MCIR2_UNIT / 2))
266 			break;
267 
268 		data->header <<= 1;
269 		if (ev.pulse)
270 			data->header |= 1;
271 		data->count++;
272 		data->state = STATE_HEADER_BIT_END;
273 		return 0;
274 
275 	case STATE_HEADER_BIT_END:
276 		decrease_duration(&ev, MCIR2_BIT_END);
277 
278 		if (data->count != MCIR2_HEADER_NBITS) {
279 			data->state = STATE_HEADER_BIT_START;
280 			goto again;
281 		}
282 
283 		switch (mce_kbd_mode(data)) {
284 		case MCIR2_MODE_KEYBOARD:
285 			data->wanted_bits = MCIR2_KEYBOARD_NBITS;
286 			break;
287 		case MCIR2_MODE_MOUSE:
288 			data->wanted_bits = MCIR2_MOUSE_NBITS;
289 			break;
290 		default:
291 			dev_dbg(&dev->dev, "not keyboard or mouse data\n");
292 			goto out;
293 		}
294 
295 		data->count = 0;
296 		data->body = 0;
297 		data->state = STATE_BODY_BIT_START;
298 		goto again;
299 
300 	case STATE_BODY_BIT_START:
301 		if (geq_margin(ev.duration, MCIR2_MAX_LEN, MCIR2_UNIT / 2))
302 			break;
303 
304 		data->body <<= 1;
305 		if (ev.pulse)
306 			data->body |= 1;
307 		data->count++;
308 		data->state = STATE_BODY_BIT_END;
309 		return 0;
310 
311 	case STATE_BODY_BIT_END:
312 		if (data->count == data->wanted_bits)
313 			data->state = STATE_FINISHED;
314 		else
315 			data->state = STATE_BODY_BIT_START;
316 
317 		decrease_duration(&ev, MCIR2_BIT_END);
318 		goto again;
319 
320 	case STATE_FINISHED:
321 		if (ev.pulse)
322 			break;
323 
324 		switch (data->wanted_bits) {
325 		case MCIR2_KEYBOARD_NBITS:
326 			scancode = data->body & 0xffffff;
327 			dev_dbg(&dev->dev, "keyboard data 0x%08x\n",
328 				data->body);
329 			spin_lock(&data->keylock);
330 			if (scancode) {
331 				delay = nsecs_to_jiffies(dev->timeout) +
332 					msecs_to_jiffies(100);
333 				mod_timer(&data->rx_timeout, jiffies + delay);
334 			} else {
335 				del_timer(&data->rx_timeout);
336 			}
337 			/* Pass data to keyboard buffer parser */
338 			ir_mce_kbd_process_keyboard_data(dev, scancode);
339 			spin_unlock(&data->keylock);
340 			lsc.rc_proto = RC_PROTO_MCIR2_KBD;
341 			break;
342 		case MCIR2_MOUSE_NBITS:
343 			scancode = data->body & 0x1fffff;
344 			dev_dbg(&dev->dev, "mouse data 0x%06x\n", scancode);
345 			/* Pass data to mouse buffer parser */
346 			ir_mce_kbd_process_mouse_data(dev, scancode);
347 			lsc.rc_proto = RC_PROTO_MCIR2_MSE;
348 			break;
349 		default:
350 			dev_dbg(&dev->dev, "not keyboard or mouse data\n");
351 			goto out;
352 		}
353 
354 		lsc.scancode = scancode;
355 		ir_lirc_scancode_event(dev, &lsc);
356 		data->state = STATE_INACTIVE;
357 		input_event(dev->input_dev, EV_MSC, MSC_SCAN, scancode);
358 		input_sync(dev->input_dev);
359 		return 0;
360 	}
361 
362 out:
363 	dev_dbg(&dev->dev, "failed at state %i (%uus %s)\n",
364 		data->state, TO_US(ev.duration), TO_STR(ev.pulse));
365 	data->state = STATE_INACTIVE;
366 	return -EINVAL;
367 }
368 
369 static int ir_mce_kbd_register(struct rc_dev *dev)
370 {
371 	struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
372 
373 	timer_setup(&mce_kbd->rx_timeout, mce_kbd_rx_timeout, 0);
374 	spin_lock_init(&mce_kbd->keylock);
375 
376 	return 0;
377 }
378 
379 static int ir_mce_kbd_unregister(struct rc_dev *dev)
380 {
381 	struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
382 
383 	del_timer_sync(&mce_kbd->rx_timeout);
384 
385 	return 0;
386 }
387 
388 static const struct ir_raw_timings_manchester ir_mce_kbd_timings = {
389 	.leader_pulse	= MCIR2_PREFIX_PULSE,
390 	.invert		= 1,
391 	.clock		= MCIR2_UNIT,
392 	.trailer_space	= MCIR2_UNIT * 10,
393 };
394 
395 /**
396  * ir_mce_kbd_encode() - Encode a scancode as a stream of raw events
397  *
398  * @protocol:   protocol to encode
399  * @scancode:   scancode to encode
400  * @events:     array of raw ir events to write into
401  * @max:        maximum size of @events
402  *
403  * Returns:     The number of events written.
404  *              -ENOBUFS if there isn't enough space in the array to fit the
405  *              encoding. In this case all @max events will have been written.
406  */
407 static int ir_mce_kbd_encode(enum rc_proto protocol, u32 scancode,
408 			     struct ir_raw_event *events, unsigned int max)
409 {
410 	struct ir_raw_event *e = events;
411 	int len, ret;
412 	u64 raw;
413 
414 	if (protocol == RC_PROTO_MCIR2_KBD) {
415 		raw = scancode |
416 		      ((u64)MCIR2_KEYBOARD_HEADER << MCIR2_KEYBOARD_NBITS);
417 		len = MCIR2_KEYBOARD_NBITS + MCIR2_HEADER_NBITS;
418 	} else {
419 		raw = scancode |
420 		      ((u64)MCIR2_MOUSE_HEADER << MCIR2_MOUSE_NBITS);
421 		len = MCIR2_MOUSE_NBITS + MCIR2_HEADER_NBITS;
422 	}
423 
424 	ret = ir_raw_gen_manchester(&e, max, &ir_mce_kbd_timings, len, raw);
425 	if (ret < 0)
426 		return ret;
427 
428 	return e - events;
429 }
430 
431 static struct ir_raw_handler mce_kbd_handler = {
432 	.protocols	= RC_PROTO_BIT_MCIR2_KBD | RC_PROTO_BIT_MCIR2_MSE,
433 	.decode		= ir_mce_kbd_decode,
434 	.encode		= ir_mce_kbd_encode,
435 	.raw_register	= ir_mce_kbd_register,
436 	.raw_unregister	= ir_mce_kbd_unregister,
437 	.carrier	= 36000,
438 	.min_timeout	= MCIR2_MAX_LEN + MCIR2_UNIT / 2,
439 };
440 
441 static int __init ir_mce_kbd_decode_init(void)
442 {
443 	ir_raw_handler_register(&mce_kbd_handler);
444 
445 	printk(KERN_INFO "IR MCE Keyboard/mouse protocol handler initialized\n");
446 	return 0;
447 }
448 
449 static void __exit ir_mce_kbd_decode_exit(void)
450 {
451 	ir_raw_handler_unregister(&mce_kbd_handler);
452 }
453 
454 module_init(ir_mce_kbd_decode_init);
455 module_exit(ir_mce_kbd_decode_exit);
456 
457 MODULE_LICENSE("GPL");
458 MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
459 MODULE_DESCRIPTION("MCE Keyboard/mouse IR protocol decoder");
460