xref: /openbmc/linux/drivers/input/serio/libps2.c (revision e8f6f3b4) 
1 /*
2  * PS/2 driver library
3  *
4  * Copyright (c) 1999-2002 Vojtech Pavlik
5  * Copyright (c) 2004 Dmitry Torokhov
6  */
7 
8 /*
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU General Public License version 2 as published by
11  * the Free Software Foundation.
12  */
13 
14 #include <linux/delay.h>
15 #include <linux/module.h>
16 #include <linux/sched.h>
17 #include <linux/interrupt.h>
18 #include <linux/input.h>
19 #include <linux/serio.h>
20 #include <linux/i8042.h>
21 #include <linux/libps2.h>
22 
23 #define DRIVER_DESC	"PS/2 driver library"
24 
25 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
26 MODULE_DESCRIPTION("PS/2 driver library");
27 MODULE_LICENSE("GPL");
28 
29 /*
30  * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
31  * It doesn't handle retransmission, though it could - because if there
32  * is a need for retransmissions device has to be replaced anyway.
33  *
34  * ps2_sendbyte() can only be called from a process context.
35  */
36 
37 int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
38 {
39 	serio_pause_rx(ps2dev->serio);
40 	ps2dev->nak = 1;
41 	ps2dev->flags |= PS2_FLAG_ACK;
42 	serio_continue_rx(ps2dev->serio);
43 
44 	if (serio_write(ps2dev->serio, byte) == 0)
45 		wait_event_timeout(ps2dev->wait,
46 				   !(ps2dev->flags & PS2_FLAG_ACK),
47 				   msecs_to_jiffies(timeout));
48 
49 	serio_pause_rx(ps2dev->serio);
50 	ps2dev->flags &= ~PS2_FLAG_ACK;
51 	serio_continue_rx(ps2dev->serio);
52 
53 	return -ps2dev->nak;
54 }
55 EXPORT_SYMBOL(ps2_sendbyte);
56 
57 void ps2_begin_command(struct ps2dev *ps2dev)
58 {
59 	mutex_lock(&ps2dev->cmd_mutex);
60 
61 	if (i8042_check_port_owner(ps2dev->serio))
62 		i8042_lock_chip();
63 }
64 EXPORT_SYMBOL(ps2_begin_command);
65 
66 void ps2_end_command(struct ps2dev *ps2dev)
67 {
68 	if (i8042_check_port_owner(ps2dev->serio))
69 		i8042_unlock_chip();
70 
71 	mutex_unlock(&ps2dev->cmd_mutex);
72 }
73 EXPORT_SYMBOL(ps2_end_command);
74 
75 /*
76  * ps2_drain() waits for device to transmit requested number of bytes
77  * and discards them.
78  */
79 
80 void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
81 {
82 	if (maxbytes > sizeof(ps2dev->cmdbuf)) {
83 		WARN_ON(1);
84 		maxbytes = sizeof(ps2dev->cmdbuf);
85 	}
86 
87 	ps2_begin_command(ps2dev);
88 
89 	serio_pause_rx(ps2dev->serio);
90 	ps2dev->flags = PS2_FLAG_CMD;
91 	ps2dev->cmdcnt = maxbytes;
92 	serio_continue_rx(ps2dev->serio);
93 
94 	wait_event_timeout(ps2dev->wait,
95 			   !(ps2dev->flags & PS2_FLAG_CMD),
96 			   msecs_to_jiffies(timeout));
97 
98 	ps2_end_command(ps2dev);
99 }
100 EXPORT_SYMBOL(ps2_drain);
101 
102 /*
103  * ps2_is_keyboard_id() checks received ID byte against the list of
104  * known keyboard IDs.
105  */
106 
107 int ps2_is_keyboard_id(char id_byte)
108 {
109 	static const char keyboard_ids[] = {
110 		0xab,	/* Regular keyboards		*/
111 		0xac,	/* NCD Sun keyboard		*/
112 		0x2b,	/* Trust keyboard, translated	*/
113 		0x5d,	/* Trust keyboard		*/
114 		0x60,	/* NMB SGI keyboard, translated */
115 		0x47,	/* NMB SGI keyboard		*/
116 	};
117 
118 	return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
119 }
120 EXPORT_SYMBOL(ps2_is_keyboard_id);
121 
122 /*
123  * ps2_adjust_timeout() is called after receiving 1st byte of command
124  * response and tries to reduce remaining timeout to speed up command
125  * completion.
126  */
127 
128 static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
129 {
130 	switch (command) {
131 		case PS2_CMD_RESET_BAT:
132 			/*
133 			 * Device has sent the first response byte after
134 			 * reset command, reset is thus done, so we can
135 			 * shorten the timeout.
136 			 * The next byte will come soon (keyboard) or not
137 			 * at all (mouse).
138 			 */
139 			if (timeout > msecs_to_jiffies(100))
140 				timeout = msecs_to_jiffies(100);
141 			break;
142 
143 		case PS2_CMD_GETID:
144 			/*
145 			 * Microsoft Natural Elite keyboard responds to
146 			 * the GET ID command as it were a mouse, with
147 			 * a single byte. Fail the command so atkbd will
148 			 * use alternative probe to detect it.
149 			 */
150 			if (ps2dev->cmdbuf[1] == 0xaa) {
151 				serio_pause_rx(ps2dev->serio);
152 				ps2dev->flags = 0;
153 				serio_continue_rx(ps2dev->serio);
154 				timeout = 0;
155 			}
156 
157 			/*
158 			 * If device behind the port is not a keyboard there
159 			 * won't be 2nd byte of ID response.
160 			 */
161 			if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
162 				serio_pause_rx(ps2dev->serio);
163 				ps2dev->flags = ps2dev->cmdcnt = 0;
164 				serio_continue_rx(ps2dev->serio);
165 				timeout = 0;
166 			}
167 			break;
168 
169 		default:
170 			break;
171 	}
172 
173 	return timeout;
174 }
175 
176 /*
177  * ps2_command() sends a command and its parameters to the mouse,
178  * then waits for the response and puts it in the param array.
179  *
180  * ps2_command() can only be called from a process context
181  */
182 
183 int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
184 {
185 	int timeout;
186 	int send = (command >> 12) & 0xf;
187 	int receive = (command >> 8) & 0xf;
188 	int rc = -1;
189 	int i;
190 
191 	if (receive > sizeof(ps2dev->cmdbuf)) {
192 		WARN_ON(1);
193 		return -1;
194 	}
195 
196 	if (send && !param) {
197 		WARN_ON(1);
198 		return -1;
199 	}
200 
201 	serio_pause_rx(ps2dev->serio);
202 	ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
203 	ps2dev->cmdcnt = receive;
204 	if (receive && param)
205 		for (i = 0; i < receive; i++)
206 			ps2dev->cmdbuf[(receive - 1) - i] = param[i];
207 	serio_continue_rx(ps2dev->serio);
208 
209 	/*
210 	 * Some devices (Synaptics) peform the reset before
211 	 * ACKing the reset command, and so it can take a long
212 	 * time before the ACK arrives.
213 	 */
214 	if (ps2_sendbyte(ps2dev, command & 0xff,
215 			 command == PS2_CMD_RESET_BAT ? 1000 : 200))
216 		goto out;
217 
218 	for (i = 0; i < send; i++)
219 		if (ps2_sendbyte(ps2dev, param[i], 200))
220 			goto out;
221 
222 	/*
223 	 * The reset command takes a long time to execute.
224 	 */
225 	timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
226 
227 	timeout = wait_event_timeout(ps2dev->wait,
228 				     !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
229 
230 	if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
231 
232 		timeout = ps2_adjust_timeout(ps2dev, command, timeout);
233 		wait_event_timeout(ps2dev->wait,
234 				   !(ps2dev->flags & PS2_FLAG_CMD), timeout);
235 	}
236 
237 	if (param)
238 		for (i = 0; i < receive; i++)
239 			param[i] = ps2dev->cmdbuf[(receive - 1) - i];
240 
241 	if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
242 		goto out;
243 
244 	rc = 0;
245 
246  out:
247 	serio_pause_rx(ps2dev->serio);
248 	ps2dev->flags = 0;
249 	serio_continue_rx(ps2dev->serio);
250 
251 	return rc;
252 }
253 EXPORT_SYMBOL(__ps2_command);
254 
255 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
256 {
257 	int rc;
258 
259 	ps2_begin_command(ps2dev);
260 	rc = __ps2_command(ps2dev, param, command);
261 	ps2_end_command(ps2dev);
262 
263 	return rc;
264 }
265 EXPORT_SYMBOL(ps2_command);
266 
267 /*
268  * ps2_init() initializes ps2dev structure
269  */
270 
271 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
272 {
273 	mutex_init(&ps2dev->cmd_mutex);
274 	lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
275 	init_waitqueue_head(&ps2dev->wait);
276 	ps2dev->serio = serio;
277 }
278 EXPORT_SYMBOL(ps2_init);
279 
280 /*
281  * ps2_handle_ack() is supposed to be used in interrupt handler
282  * to properly process ACK/NAK of a command from a PS/2 device.
283  */
284 
285 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
286 {
287 	switch (data) {
288 		case PS2_RET_ACK:
289 			ps2dev->nak = 0;
290 			break;
291 
292 		case PS2_RET_NAK:
293 			ps2dev->flags |= PS2_FLAG_NAK;
294 			ps2dev->nak = PS2_RET_NAK;
295 			break;
296 
297 		case PS2_RET_ERR:
298 			if (ps2dev->flags & PS2_FLAG_NAK) {
299 				ps2dev->flags &= ~PS2_FLAG_NAK;
300 				ps2dev->nak = PS2_RET_ERR;
301 				break;
302 			}
303 
304 		/*
305 		 * Workaround for mice which don't ACK the Get ID command.
306 		 * These are valid mouse IDs that we recognize.
307 		 */
308 		case 0x00:
309 		case 0x03:
310 		case 0x04:
311 			if (ps2dev->flags & PS2_FLAG_WAITID) {
312 				ps2dev->nak = 0;
313 				break;
314 			}
315 			/* Fall through */
316 		default:
317 			return 0;
318 	}
319 
320 
321 	if (!ps2dev->nak) {
322 		ps2dev->flags &= ~PS2_FLAG_NAK;
323 		if (ps2dev->cmdcnt)
324 			ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
325 	}
326 
327 	ps2dev->flags &= ~PS2_FLAG_ACK;
328 	wake_up(&ps2dev->wait);
329 
330 	if (data != PS2_RET_ACK)
331 		ps2_handle_response(ps2dev, data);
332 
333 	return 1;
334 }
335 EXPORT_SYMBOL(ps2_handle_ack);
336 
337 /*
338  * ps2_handle_response() is supposed to be used in interrupt handler
339  * to properly store device's response to a command and notify process
340  * waiting for completion of the command.
341  */
342 
343 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
344 {
345 	if (ps2dev->cmdcnt)
346 		ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
347 
348 	if (ps2dev->flags & PS2_FLAG_CMD1) {
349 		ps2dev->flags &= ~PS2_FLAG_CMD1;
350 		if (ps2dev->cmdcnt)
351 			wake_up(&ps2dev->wait);
352 	}
353 
354 	if (!ps2dev->cmdcnt) {
355 		ps2dev->flags &= ~PS2_FLAG_CMD;
356 		wake_up(&ps2dev->wait);
357 	}
358 
359 	return 1;
360 }
361 EXPORT_SYMBOL(ps2_handle_response);
362 
363 void ps2_cmd_aborted(struct ps2dev *ps2dev)
364 {
365 	if (ps2dev->flags & PS2_FLAG_ACK)
366 		ps2dev->nak = 1;
367 
368 	if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
369 		wake_up(&ps2dev->wait);
370 
371 	/* reset all flags except last nack */
372 	ps2dev->flags &= PS2_FLAG_NAK;
373 }
374 EXPORT_SYMBOL(ps2_cmd_aborted);
375