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
ps2_sendbyte(struct ps2dev * ps2dev,unsigned char byte,int timeout)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
ps2_begin_command(struct ps2dev * ps2dev)57 void ps2_begin_command(struct ps2dev *ps2dev)
58 {
59 struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
60
61 mutex_lock(m);
62 }
63 EXPORT_SYMBOL(ps2_begin_command);
64
ps2_end_command(struct ps2dev * ps2dev)65 void ps2_end_command(struct ps2dev *ps2dev)
66 {
67 struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
68
69 mutex_unlock(m);
70 }
71 EXPORT_SYMBOL(ps2_end_command);
72
73 /*
74 * ps2_drain() waits for device to transmit requested number of bytes
75 * and discards them.
76 */
77
ps2_drain(struct ps2dev * ps2dev,int maxbytes,int timeout)78 void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
79 {
80 if (maxbytes > sizeof(ps2dev->cmdbuf)) {
81 WARN_ON(1);
82 maxbytes = sizeof(ps2dev->cmdbuf);
83 }
84
85 ps2_begin_command(ps2dev);
86
87 serio_pause_rx(ps2dev->serio);
88 ps2dev->flags = PS2_FLAG_CMD;
89 ps2dev->cmdcnt = maxbytes;
90 serio_continue_rx(ps2dev->serio);
91
92 wait_event_timeout(ps2dev->wait,
93 !(ps2dev->flags & PS2_FLAG_CMD),
94 msecs_to_jiffies(timeout));
95
96 ps2_end_command(ps2dev);
97 }
98 EXPORT_SYMBOL(ps2_drain);
99
100 /*
101 * ps2_is_keyboard_id() checks received ID byte against the list of
102 * known keyboard IDs.
103 */
104
ps2_is_keyboard_id(char id_byte)105 int ps2_is_keyboard_id(char id_byte)
106 {
107 static const char keyboard_ids[] = {
108 0xab, /* Regular keyboards */
109 0xac, /* NCD Sun keyboard */
110 0x2b, /* Trust keyboard, translated */
111 0x5d, /* Trust keyboard */
112 0x60, /* NMB SGI keyboard, translated */
113 0x47, /* NMB SGI keyboard */
114 };
115
116 return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
117 }
118 EXPORT_SYMBOL(ps2_is_keyboard_id);
119
120 /*
121 * ps2_adjust_timeout() is called after receiving 1st byte of command
122 * response and tries to reduce remaining timeout to speed up command
123 * completion.
124 */
125
ps2_adjust_timeout(struct ps2dev * ps2dev,int command,int timeout)126 static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
127 {
128 switch (command) {
129 case PS2_CMD_RESET_BAT:
130 /*
131 * Device has sent the first response byte after
132 * reset command, reset is thus done, so we can
133 * shorten the timeout.
134 * The next byte will come soon (keyboard) or not
135 * at all (mouse).
136 */
137 if (timeout > msecs_to_jiffies(100))
138 timeout = msecs_to_jiffies(100);
139 break;
140
141 case PS2_CMD_GETID:
142 /*
143 * Microsoft Natural Elite keyboard responds to
144 * the GET ID command as it were a mouse, with
145 * a single byte. Fail the command so atkbd will
146 * use alternative probe to detect it.
147 */
148 if (ps2dev->cmdbuf[1] == 0xaa) {
149 serio_pause_rx(ps2dev->serio);
150 ps2dev->flags = 0;
151 serio_continue_rx(ps2dev->serio);
152 timeout = 0;
153 }
154
155 /*
156 * If device behind the port is not a keyboard there
157 * won't be 2nd byte of ID response.
158 */
159 if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
160 serio_pause_rx(ps2dev->serio);
161 ps2dev->flags = ps2dev->cmdcnt = 0;
162 serio_continue_rx(ps2dev->serio);
163 timeout = 0;
164 }
165 break;
166
167 default:
168 break;
169 }
170
171 return timeout;
172 }
173
174 /*
175 * ps2_command() sends a command and its parameters to the mouse,
176 * then waits for the response and puts it in the param array.
177 *
178 * ps2_command() can only be called from a process context
179 */
180
__ps2_command(struct ps2dev * ps2dev,unsigned char * param,int command)181 int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
182 {
183 int timeout;
184 int send = (command >> 12) & 0xf;
185 int receive = (command >> 8) & 0xf;
186 int rc = -1;
187 int i;
188
189 if (receive > sizeof(ps2dev->cmdbuf)) {
190 WARN_ON(1);
191 return -1;
192 }
193
194 if (send && !param) {
195 WARN_ON(1);
196 return -1;
197 }
198
199 serio_pause_rx(ps2dev->serio);
200 ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
201 ps2dev->cmdcnt = receive;
202 if (receive && param)
203 for (i = 0; i < receive; i++)
204 ps2dev->cmdbuf[(receive - 1) - i] = param[i];
205 serio_continue_rx(ps2dev->serio);
206
207 /*
208 * Some devices (Synaptics) peform the reset before
209 * ACKing the reset command, and so it can take a long
210 * time before the ACK arrives.
211 */
212 if (ps2_sendbyte(ps2dev, command & 0xff,
213 command == PS2_CMD_RESET_BAT ? 1000 : 200)) {
214 serio_pause_rx(ps2dev->serio);
215 goto out_reset_flags;
216 }
217
218 for (i = 0; i < send; i++) {
219 if (ps2_sendbyte(ps2dev, param[i], 200)) {
220 serio_pause_rx(ps2dev->serio);
221 goto out_reset_flags;
222 }
223 }
224
225 /*
226 * The reset command takes a long time to execute.
227 */
228 timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
229
230 timeout = wait_event_timeout(ps2dev->wait,
231 !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
232
233 if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
234
235 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
236 wait_event_timeout(ps2dev->wait,
237 !(ps2dev->flags & PS2_FLAG_CMD), timeout);
238 }
239
240 serio_pause_rx(ps2dev->serio);
241
242 if (param)
243 for (i = 0; i < receive; i++)
244 param[i] = ps2dev->cmdbuf[(receive - 1) - i];
245
246 if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
247 goto out_reset_flags;
248
249 rc = 0;
250
251 out_reset_flags:
252 ps2dev->flags = 0;
253 serio_continue_rx(ps2dev->serio);
254
255 return rc;
256 }
257 EXPORT_SYMBOL(__ps2_command);
258
ps2_command(struct ps2dev * ps2dev,unsigned char * param,int command)259 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
260 {
261 int rc;
262
263 ps2_begin_command(ps2dev);
264 rc = __ps2_command(ps2dev, param, command);
265 ps2_end_command(ps2dev);
266
267 return rc;
268 }
269 EXPORT_SYMBOL(ps2_command);
270
271 /*
272 * ps2_init() initializes ps2dev structure
273 */
274
ps2_init(struct ps2dev * ps2dev,struct serio * serio)275 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
276 {
277 mutex_init(&ps2dev->cmd_mutex);
278 lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
279 init_waitqueue_head(&ps2dev->wait);
280 ps2dev->serio = serio;
281 }
282 EXPORT_SYMBOL(ps2_init);
283
284 /*
285 * ps2_handle_ack() is supposed to be used in interrupt handler
286 * to properly process ACK/NAK of a command from a PS/2 device.
287 */
288
ps2_handle_ack(struct ps2dev * ps2dev,unsigned char data)289 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
290 {
291 switch (data) {
292 case PS2_RET_ACK:
293 ps2dev->nak = 0;
294 break;
295
296 case PS2_RET_NAK:
297 ps2dev->flags |= PS2_FLAG_NAK;
298 ps2dev->nak = PS2_RET_NAK;
299 break;
300
301 case PS2_RET_ERR:
302 if (ps2dev->flags & PS2_FLAG_NAK) {
303 ps2dev->flags &= ~PS2_FLAG_NAK;
304 ps2dev->nak = PS2_RET_ERR;
305 break;
306 }
307
308 /*
309 * Workaround for mice which don't ACK the Get ID command.
310 * These are valid mouse IDs that we recognize.
311 */
312 case 0x00:
313 case 0x03:
314 case 0x04:
315 if (ps2dev->flags & PS2_FLAG_WAITID) {
316 ps2dev->nak = 0;
317 break;
318 }
319 /* Fall through */
320 default:
321 return 0;
322 }
323
324
325 if (!ps2dev->nak) {
326 ps2dev->flags &= ~PS2_FLAG_NAK;
327 if (ps2dev->cmdcnt)
328 ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
329 }
330
331 ps2dev->flags &= ~PS2_FLAG_ACK;
332 wake_up(&ps2dev->wait);
333
334 if (data != PS2_RET_ACK)
335 ps2_handle_response(ps2dev, data);
336
337 return 1;
338 }
339 EXPORT_SYMBOL(ps2_handle_ack);
340
341 /*
342 * ps2_handle_response() is supposed to be used in interrupt handler
343 * to properly store device's response to a command and notify process
344 * waiting for completion of the command.
345 */
346
ps2_handle_response(struct ps2dev * ps2dev,unsigned char data)347 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
348 {
349 if (ps2dev->cmdcnt)
350 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
351
352 if (ps2dev->flags & PS2_FLAG_CMD1) {
353 ps2dev->flags &= ~PS2_FLAG_CMD1;
354 if (ps2dev->cmdcnt)
355 wake_up(&ps2dev->wait);
356 }
357
358 if (!ps2dev->cmdcnt) {
359 ps2dev->flags &= ~PS2_FLAG_CMD;
360 wake_up(&ps2dev->wait);
361 }
362
363 return 1;
364 }
365 EXPORT_SYMBOL(ps2_handle_response);
366
ps2_cmd_aborted(struct ps2dev * ps2dev)367 void ps2_cmd_aborted(struct ps2dev *ps2dev)
368 {
369 if (ps2dev->flags & PS2_FLAG_ACK)
370 ps2dev->nak = 1;
371
372 if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
373 wake_up(&ps2dev->wait);
374
375 /* reset all flags except last nack */
376 ps2dev->flags &= PS2_FLAG_NAK;
377 }
378 EXPORT_SYMBOL(ps2_cmd_aborted);
379