summaryrefslogtreecommitdiffstats
path: root/drivers/input/serio/libps2.c
blob: e5b1b60757bb8d7a965aa92a87ffbae2e0264042 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
/*
 * PS/2 driver library
 *
 * Copyright (c) 1999-2002 Vojtech Pavlik
 * Copyright (c) 2004 Dmitry Torokhov
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/delay.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/init.h>
#include <linux/libps2.h>

#define DRIVER_DESC	"PS/2 driver library"

MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
MODULE_DESCRIPTION("PS/2 driver library");
MODULE_LICENSE("GPL");

/* Work structure to schedule execution of a command */
struct ps2work {
	struct work_struct work;
	struct ps2dev *ps2dev;
	int command;
	unsigned char param[0];
};


/*
 * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
 * It doesn't handle retransmission, though it could - because if there
 * is a need for retransmissions device has to be replaced anyway.
 *
 * ps2_sendbyte() can only be called from a process context.
 */

int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
{
	serio_pause_rx(ps2dev->serio);
	ps2dev->nak = 1;
	ps2dev->flags |= PS2_FLAG_ACK;
	serio_continue_rx(ps2dev->serio);

	if (serio_write(ps2dev->serio, byte) == 0)
		wait_event_timeout(ps2dev->wait,
				   !(ps2dev->flags & PS2_FLAG_ACK),
				   msecs_to_jiffies(timeout));

	serio_pause_rx(ps2dev->serio);
	ps2dev->flags &= ~PS2_FLAG_ACK;
	serio_continue_rx(ps2dev->serio);

	return -ps2dev->nak;
}
EXPORT_SYMBOL(ps2_sendbyte);

/*
 * ps2_drain() waits for device to transmit requested number of bytes
 * and discards them.
 */

void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
{
	if (maxbytes > sizeof(ps2dev->cmdbuf)) {
		WARN_ON(1);
		maxbytes = sizeof(ps2dev->cmdbuf);
	}

	mutex_lock(&ps2dev->cmd_mutex);

	serio_pause_rx(ps2dev->serio);
	ps2dev->flags = PS2_FLAG_CMD;
	ps2dev->cmdcnt = maxbytes;
	serio_continue_rx(ps2dev->serio);

	wait_event_timeout(ps2dev->wait,
			   !(ps2dev->flags & PS2_FLAG_CMD),
			   msecs_to_jiffies(timeout));
	mutex_unlock(&ps2dev->cmd_mutex);
}
EXPORT_SYMBOL(ps2_drain);

/*
 * ps2_is_keyboard_id() checks received ID byte against the list of
 * known keyboard IDs.
 */

int ps2_is_keyboard_id(char id_byte)
{
	const static char keyboard_ids[] = {
		0xab,	/* Regular keyboards		*/
		0xac,	/* NCD Sun keyboard		*/
		0x2b,	/* Trust keyboard, translated	*/
		0x5d,	/* Trust keyboard		*/
		0x60,	/* NMB SGI keyboard, translated */
		0x47,	/* NMB SGI keyboard		*/
	};

	return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
}
EXPORT_SYMBOL(ps2_is_keyboard_id);

/*
 * ps2_adjust_timeout() is called after receiving 1st byte of command
 * response and tries to reduce remaining timeout to speed up command
 * completion.
 */

static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
{
	switch (command) {
		case PS2_CMD_RESET_BAT:
			/*
			 * Device has sent the first response byte after
			 * reset command, reset is thus done, so we can
			 * shorten the timeout.
			 * The next byte will come soon (keyboard) or not
			 * at all (mouse).
			 */
			if (timeout > msecs_to_jiffies(100))
				timeout = msecs_to_jiffies(100);
			break;

		case PS2_CMD_GETID:
			/*
			 * Microsoft Natural Elite keyboard responds to
			 * the GET ID command as it were a mouse, with
			 * a single byte. Fail the command so atkbd will
			 * use alternative probe to detect it.
			 */
			if (ps2dev->cmdbuf[1] == 0xaa) {
				serio_pause_rx(ps2dev->serio);
				ps2dev->flags = 0;
				serio_continue_rx(ps2dev->serio);
				timeout = 0;
			}

			/*
			 * If device behind the port is not a keyboard there
			 * won't be 2nd byte of ID response.
			 */
			if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
				serio_pause_rx(ps2dev->serio);
				ps2dev->flags = ps2dev->cmdcnt = 0;
				serio_continue_rx(ps2dev->serio);
				timeout = 0;
			}
			break;

		default:
			break;
	}

	return timeout;
}

/*
 * ps2_command() sends a command and its parameters to the mouse,
 * then waits for the response and puts it in the param array.
 *
 * ps2_command() can only be called from a process context
 */

int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
{
	int timeout;
	int send = (command >> 12) & 0xf;
	int receive = (command >> 8) & 0xf;
	int rc = -1;
	int i;

	if (receive > sizeof(ps2dev->cmdbuf)) {
		WARN_ON(1);
		return -1;
	}

	if (send && !param) {
		WARN_ON(1);
		return -1;
	}

	mutex_lock(&ps2dev->cmd_mutex);

	serio_pause_rx(ps2dev->serio);
	ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
	ps2dev->cmdcnt = receive;
	if (receive && param)
		for (i = 0; i < receive; i++)
			ps2dev->cmdbuf[(receive - 1) - i] = param[i];
	serio_continue_rx(ps2dev->serio);

	/*
	 * Some devices (Synaptics) peform the reset before
	 * ACKing the reset command, and so it can take a long
	 * time before the ACK arrrives.
	 */
	if (ps2_sendbyte(ps2dev, command & 0xff,
			 command == PS2_CMD_RESET_BAT ? 1000 : 200))
		goto out;

	for (i = 0; i < send; i++)
		if (ps2_sendbyte(ps2dev, param[i], 200))
			goto out;

	/*
	 * The reset command takes a long time to execute.
	 */
	timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);

	timeout = wait_event_timeout(ps2dev->wait,
				     !(ps2dev->flags & PS2_FLAG_CMD1), timeout);

	if (ps2dev->cmdcnt && timeout > 0) {

		timeout = ps2_adjust_timeout(ps2dev, command, timeout);
		wait_event_timeout(ps2dev->wait,
				   !(ps2dev->flags & PS2_FLAG_CMD), timeout);
	}

	if (param)
		for (i = 0; i < receive; i++)
			param[i] = ps2dev->cmdbuf[(receive - 1) - i];

	if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
		goto out;

	rc = 0;

 out:
	serio_pause_rx(ps2dev->serio);
	ps2dev->flags = 0;
	serio_continue_rx(ps2dev->serio);

	mutex_unlock(&ps2dev->cmd_mutex);
	return rc;
}
EXPORT_SYMBOL(ps2_command);

/*
 * ps2_execute_scheduled_command() sends a command, previously scheduled by
 * ps2_schedule_command(), to a PS/2 device (keyboard, mouse, etc.)
 */

static void ps2_execute_scheduled_command(void *data)
{
	struct ps2work *ps2work = data;

	ps2_command(ps2work->ps2dev, ps2work->param, ps2work->command);
	kfree(ps2work);
}

/*
 * ps2_schedule_command() allows to schedule delayed execution of a PS/2
 * command and can be used to issue a command from an interrupt or softirq
 * context.
 */

int ps2_schedule_command(struct ps2dev *ps2dev, unsigned char *param, int command)
{
	struct ps2work *ps2work;
	int send = (command >> 12) & 0xf;
	int receive = (command >> 8) & 0xf;

	if (!(ps2work = kmalloc(sizeof(struct ps2work) + max(send, receive), GFP_ATOMIC)))
		return -1;

	memset(ps2work, 0, sizeof(struct ps2work));
	ps2work->ps2dev = ps2dev;
	ps2work->command = command;
	memcpy(ps2work->param, param, send);
	INIT_WORK(&ps2work->work, ps2_execute_scheduled_command, ps2work);

	if (!schedule_work(&ps2work->work)) {
		kfree(ps2work);
		return -1;
	}

	return 0;
}
EXPORT_SYMBOL(ps2_schedule_command);

/*
 * ps2_init() initializes ps2dev structure
 */

void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
{
	mutex_init(&ps2dev->cmd_mutex);
	lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
	init_waitqueue_head(&ps2dev->wait);
	ps2dev->serio = serio;
}
EXPORT_SYMBOL(ps2_init);

/*
 * ps2_handle_ack() is supposed to be used in interrupt handler
 * to properly process ACK/NAK of a command from a PS/2 device.
 */

int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
{
	switch (data) {
		case PS2_RET_ACK:
			ps2dev->nak = 0;
			break;

		case PS2_RET_NAK:
			ps2dev->nak = 1;
			break;

		/*
		 * Workaround for mice which don't ACK the Get ID command.
		 * These are valid mouse IDs that we recognize.
		 */
		case 0x00:
		case 0x03:
		case 0x04:
			if (ps2dev->flags & PS2_FLAG_WAITID) {
				ps2dev->nak = 0;
				break;
			}
			/* Fall through */
		default:
			return 0;
	}


	if (!ps2dev->nak && ps2dev->cmdcnt)
		ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;

	ps2dev->flags &= ~PS2_FLAG_ACK;
	wake_up(&ps2dev->wait);

	if (data != PS2_RET_ACK)
		ps2_handle_response(ps2dev, data);

	return 1;
}
EXPORT_SYMBOL(ps2_handle_ack);

/*
 * ps2_handle_response() is supposed to be used in interrupt handler
 * to properly store device's response to a command and notify process
 * waiting for completion of the command.
 */

int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
{
	if (ps2dev->cmdcnt)
		ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;

	if (ps2dev->flags & PS2_FLAG_CMD1) {
		ps2dev->flags &= ~PS2_FLAG_CMD1;
		if (ps2dev->cmdcnt)
			wake_up(&ps2dev->wait);
	}

	if (!ps2dev->cmdcnt) {
		ps2dev->flags &= ~PS2_FLAG_CMD;
		wake_up(&ps2dev->wait);
	}

	return 1;
}
EXPORT_SYMBOL(ps2_handle_response);

void ps2_cmd_aborted(struct ps2dev *ps2dev)
{
	if (ps2dev->flags & PS2_FLAG_ACK)
		ps2dev->nak = 1;

	if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
		wake_up(&ps2dev->wait);

	ps2dev->flags = 0;
}
EXPORT_SYMBOL(ps2_cmd_aborted);
OpenPOWER on IntegriCloud