xref: /openbmc/linux/drivers/input/serio/libps2.c (revision 7dd65feb) 
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/slab.h>
18 #include <linux/interrupt.h>
19 #include <linux/input.h>
20 #include <linux/serio.h>
21 #include <linux/i8042.h>
22 #include <linux/init.h>
23 #include <linux/libps2.h>
24 
25 #define DRIVER_DESC	"PS/2 driver library"
26 
27 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
28 MODULE_DESCRIPTION("PS/2 driver library");
29 MODULE_LICENSE("GPL");
30 
31 /*
32  * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
33  * It doesn't handle retransmission, though it could - because if there
34  * is a need for retransmissions device has to be replaced anyway.
35  *
36  * ps2_sendbyte() can only be called from a process context.
37  */
38 
39 int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
40 {
41 	serio_pause_rx(ps2dev->serio);
42 	ps2dev->nak = 1;
43 	ps2dev->flags |= PS2_FLAG_ACK;
44 	serio_continue_rx(ps2dev->serio);
45 
46 	if (serio_write(ps2dev->serio, byte) == 0)
47 		wait_event_timeout(ps2dev->wait,
48 				   !(ps2dev->flags & PS2_FLAG_ACK),
49 				   msecs_to_jiffies(timeout));
50 
51 	serio_pause_rx(ps2dev->serio);
52 	ps2dev->flags &= ~PS2_FLAG_ACK;
53 	serio_continue_rx(ps2dev->serio);
54 
55 	return -ps2dev->nak;
56 }
57 EXPORT_SYMBOL(ps2_sendbyte);
58 
59 void ps2_begin_command(struct ps2dev *ps2dev)
60 {
61 	mutex_lock(&ps2dev->cmd_mutex);
62 
63 	if (i8042_check_port_owner(ps2dev->serio))
64 		i8042_lock_chip();
65 }
66 EXPORT_SYMBOL(ps2_begin_command);
67 
68 void ps2_end_command(struct ps2dev *ps2dev)
69 {
70 	if (i8042_check_port_owner(ps2dev->serio))
71 		i8042_unlock_chip();
72 
73 	mutex_unlock(&ps2dev->cmd_mutex);
74 }
75 EXPORT_SYMBOL(ps2_end_command);
76 
77 /*
78  * ps2_drain() waits for device to transmit requested number of bytes
79  * and discards them.
80  */
81 
82 void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
83 {
84 	if (maxbytes > sizeof(ps2dev->cmdbuf)) {
85 		WARN_ON(1);
86 		maxbytes = sizeof(ps2dev->cmdbuf);
87 	}
88 
89 	ps2_begin_command(ps2dev);
90 
91 	serio_pause_rx(ps2dev->serio);
92 	ps2dev->flags = PS2_FLAG_CMD;
93 	ps2dev->cmdcnt = maxbytes;
94 	serio_continue_rx(ps2dev->serio);
95 
96 	wait_event_timeout(ps2dev->wait,
97 			   !(ps2dev->flags & PS2_FLAG_CMD),
98 			   msecs_to_jiffies(timeout));
99 
100 	ps2_end_command(ps2dev);
101 }
102 EXPORT_SYMBOL(ps2_drain);
103 
104 /*
105  * ps2_is_keyboard_id() checks received ID byte against the list of
106  * known keyboard IDs.
107  */
108 
109 int ps2_is_keyboard_id(char id_byte)
110 {
111 	static const char keyboard_ids[] = {
112 		0xab,	/* Regular keyboards		*/
113 		0xac,	/* NCD Sun keyboard		*/
114 		0x2b,	/* Trust keyboard, translated	*/
115 		0x5d,	/* Trust keyboard		*/
116 		0x60,	/* NMB SGI keyboard, translated */
117 		0x47,	/* NMB SGI keyboard		*/
118 	};
119 
120 	return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
121 }
122 EXPORT_SYMBOL(ps2_is_keyboard_id);
123 
124 /*
125  * ps2_adjust_timeout() is called after receiving 1st byte of command
126  * response and tries to reduce remaining timeout to speed up command
127  * completion.
128  */
129 
130 static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
131 {
132 	switch (command) {
133 		case PS2_CMD_RESET_BAT:
134 			/*
135 			 * Device has sent the first response byte after
136 			 * reset command, reset is thus done, so we can
137 			 * shorten the timeout.
138 			 * The next byte will come soon (keyboard) or not
139 			 * at all (mouse).
140 			 */
141 			if (timeout > msecs_to_jiffies(100))
142 				timeout = msecs_to_jiffies(100);
143 			break;
144 
145 		case PS2_CMD_GETID:
146 			/*
147 			 * Microsoft Natural Elite keyboard responds to
148 			 * the GET ID command as it were a mouse, with
149 			 * a single byte. Fail the command so atkbd will
150 			 * use alternative probe to detect it.
151 			 */
152 			if (ps2dev->cmdbuf[1] == 0xaa) {
153 				serio_pause_rx(ps2dev->serio);
154 				ps2dev->flags = 0;
155 				serio_continue_rx(ps2dev->serio);
156 				timeout = 0;
157 			}
158 
159 			/*
160 			 * If device behind the port is not a keyboard there
161 			 * won't be 2nd byte of ID response.
162 			 */
163 			if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
164 				serio_pause_rx(ps2dev->serio);
165 				ps2dev->flags = ps2dev->cmdcnt = 0;
166 				serio_continue_rx(ps2dev->serio);
167 				timeout = 0;
168 			}
169 			break;
170 
171 		default:
172 			break;
173 	}
174 
175 	return timeout;
176 }
177 
178 /*
179  * ps2_command() sends a command and its parameters to the mouse,
180  * then waits for the response and puts it in the param array.
181  *
182  * ps2_command() can only be called from a process context
183  */
184 
185 int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
186 {
187 	int timeout;
188 	int send = (command >> 12) & 0xf;
189 	int receive = (command >> 8) & 0xf;
190 	int rc = -1;
191 	int i;
192 
193 	if (receive > sizeof(ps2dev->cmdbuf)) {
194 		WARN_ON(1);
195 		return -1;
196 	}
197 
198 	if (send && !param) {
199 		WARN_ON(1);
200 		return -1;
201 	}
202 
203 	serio_pause_rx(ps2dev->serio);
204 	ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
205 	ps2dev->cmdcnt = receive;
206 	if (receive && param)
207 		for (i = 0; i < receive; i++)
208 			ps2dev->cmdbuf[(receive - 1) - i] = param[i];
209 	serio_continue_rx(ps2dev->serio);
210 
211 	/*
212 	 * Some devices (Synaptics) peform the reset before
213 	 * ACKing the reset command, and so it can take a long
214 	 * time before the ACK arrrives.
215 	 */
216 	if (ps2_sendbyte(ps2dev, command & 0xff,
217 			 command == PS2_CMD_RESET_BAT ? 1000 : 200))
218 		goto out;
219 
220 	for (i = 0; i < send; i++)
221 		if (ps2_sendbyte(ps2dev, param[i], 200))
222 			goto out;
223 
224 	/*
225 	 * The reset command takes a long time to execute.
226 	 */
227 	timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
228 
229 	timeout = wait_event_timeout(ps2dev->wait,
230 				     !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
231 
232 	if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
233 
234 		timeout = ps2_adjust_timeout(ps2dev, command, timeout);
235 		wait_event_timeout(ps2dev->wait,
236 				   !(ps2dev->flags & PS2_FLAG_CMD), timeout);
237 	}
238 
239 	if (param)
240 		for (i = 0; i < receive; i++)
241 			param[i] = ps2dev->cmdbuf[(receive - 1) - i];
242 
243 	if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
244 		goto out;
245 
246 	rc = 0;
247 
248  out:
249 	serio_pause_rx(ps2dev->serio);
250 	ps2dev->flags = 0;
251 	serio_continue_rx(ps2dev->serio);
252 
253 	return rc;
254 }
255 EXPORT_SYMBOL(__ps2_command);
256 
257 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
258 {
259 	int rc;
260 
261 	ps2_begin_command(ps2dev);
262 	rc = __ps2_command(ps2dev, param, command);
263 	ps2_end_command(ps2dev);
264 
265 	return rc;
266 }
267 EXPORT_SYMBOL(ps2_command);
268 
269 /*
270  * ps2_init() initializes ps2dev structure
271  */
272 
273 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
274 {
275 	mutex_init(&ps2dev->cmd_mutex);
276 	lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
277 	init_waitqueue_head(&ps2dev->wait);
278 	ps2dev->serio = serio;
279 }
280 EXPORT_SYMBOL(ps2_init);
281 
282 /*
283  * ps2_handle_ack() is supposed to be used in interrupt handler
284  * to properly process ACK/NAK of a command from a PS/2 device.
285  */
286 
287 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
288 {
289 	switch (data) {
290 		case PS2_RET_ACK:
291 			ps2dev->nak = 0;
292 			break;
293 
294 		case PS2_RET_NAK:
295 			ps2dev->flags |= PS2_FLAG_NAK;
296 			ps2dev->nak = PS2_RET_NAK;
297 			break;
298 
299 		case PS2_RET_ERR:
300 			if (ps2dev->flags & PS2_FLAG_NAK) {
301 				ps2dev->flags &= ~PS2_FLAG_NAK;
302 				ps2dev->nak = PS2_RET_ERR;
303 				break;
304 			}
305 
306 		/*
307 		 * Workaround for mice which don't ACK the Get ID command.
308 		 * These are valid mouse IDs that we recognize.
309 		 */
310 		case 0x00:
311 		case 0x03:
312 		case 0x04:
313 			if (ps2dev->flags & PS2_FLAG_WAITID) {
314 				ps2dev->nak = 0;
315 				break;
316 			}
317 			/* Fall through */
318 		default:
319 			return 0;
320 	}
321 
322 
323 	if (!ps2dev->nak) {
324 		ps2dev->flags &= ~PS2_FLAG_NAK;
325 		if (ps2dev->cmdcnt)
326 			ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
327 	}
328 
329 	ps2dev->flags &= ~PS2_FLAG_ACK;
330 	wake_up(&ps2dev->wait);
331 
332 	if (data != PS2_RET_ACK)
333 		ps2_handle_response(ps2dev, data);
334 
335 	return 1;
336 }
337 EXPORT_SYMBOL(ps2_handle_ack);
338 
339 /*
340  * ps2_handle_response() is supposed to be used in interrupt handler
341  * to properly store device's response to a command and notify process
342  * waiting for completion of the command.
343  */
344 
345 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
346 {
347 	if (ps2dev->cmdcnt)
348 		ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
349 
350 	if (ps2dev->flags & PS2_FLAG_CMD1) {
351 		ps2dev->flags &= ~PS2_FLAG_CMD1;
352 		if (ps2dev->cmdcnt)
353 			wake_up(&ps2dev->wait);
354 	}
355 
356 	if (!ps2dev->cmdcnt) {
357 		ps2dev->flags &= ~PS2_FLAG_CMD;
358 		wake_up(&ps2dev->wait);
359 	}
360 
361 	return 1;
362 }
363 EXPORT_SYMBOL(ps2_handle_response);
364 
365 void ps2_cmd_aborted(struct ps2dev *ps2dev)
366 {
367 	if (ps2dev->flags & PS2_FLAG_ACK)
368 		ps2dev->nak = 1;
369 
370 	if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
371 		wake_up(&ps2dev->wait);
372 
373 	/* reset all flags except last nack */
374 	ps2dev->flags &= PS2_FLAG_NAK;
375 }
376 EXPORT_SYMBOL(ps2_cmd_aborted);
377