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
25MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
26MODULE_DESCRIPTION("PS/2 driver library");
27MODULE_LICENSE("GPL");
28
29static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte,
30 unsigned int timeout, unsigned int max_attempts)
31 __releases(&ps2dev->serio->lock) __acquires(&ps2dev->serio->lock)
32{
33 int attempt = 0;
34 int error;
35
36 lockdep_assert_held(&ps2dev->serio->lock);
37
38 do {
39 ps2dev->nak = 1;
40 ps2dev->flags |= PS2_FLAG_ACK;
41
42 serio_continue_rx(ps2dev->serio);
43
44 error = serio_write(ps2dev->serio, byte);
45 if (error)
46 dev_dbg(&ps2dev->serio->dev,
47 "failed to write %#02x: %d\n", byte, error);
48 else
49 wait_event_timeout(ps2dev->wait,
50 !(ps2dev->flags & PS2_FLAG_ACK),
51 msecs_to_jiffies(timeout));
52
53 serio_pause_rx(ps2dev->serio);
54 } while (ps2dev->nak == PS2_RET_NAK && ++attempt < max_attempts);
55
56 ps2dev->flags &= ~PS2_FLAG_ACK;
57
58 if (!error) {
59 switch (ps2dev->nak) {
60 case 0:
61 break;
62 case PS2_RET_NAK:
63 error = -EAGAIN;
64 break;
65 case PS2_RET_ERR:
66 error = -EPROTO;
67 break;
68 default:
69 error = -EIO;
70 break;
71 }
72 }
73
74 if (error || attempt > 1)
75 dev_dbg(&ps2dev->serio->dev,
76 "%02x - %d (%x), attempt %d\n",
77 byte, error, ps2dev->nak, attempt);
78
79 return error;
80}
81
82/*
83 * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
84 * It doesn't handle retransmission, the caller is expected to handle
85 * it when needed.
86 *
87 * ps2_sendbyte() can only be called from a process context.
88 */
89
90int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
91{
92 int retval;
93
94 serio_pause_rx(ps2dev->serio);
95
96 retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1);
97 dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);
98
99 serio_continue_rx(ps2dev->serio);
100
101 return retval;
102}
103EXPORT_SYMBOL(ps2_sendbyte);
104
105void ps2_begin_command(struct ps2dev *ps2dev)
106{
107 struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
108
109 mutex_lock(m);
110}
111EXPORT_SYMBOL(ps2_begin_command);
112
113void ps2_end_command(struct ps2dev *ps2dev)
114{
115 struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
116
117 mutex_unlock(m);
118}
119EXPORT_SYMBOL(ps2_end_command);
120
121/*
122 * ps2_drain() waits for device to transmit requested number of bytes
123 * and discards them.
124 */
125
126void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout)
127{
128 if (maxbytes > sizeof(ps2dev->cmdbuf)) {
129 WARN_ON(1);
130 maxbytes = sizeof(ps2dev->cmdbuf);
131 }
132
133 ps2_begin_command(ps2dev);
134
135 serio_pause_rx(ps2dev->serio);
136 ps2dev->flags = PS2_FLAG_CMD;
137 ps2dev->cmdcnt = maxbytes;
138 serio_continue_rx(ps2dev->serio);
139
140 wait_event_timeout(ps2dev->wait,
141 !(ps2dev->flags & PS2_FLAG_CMD),
142 msecs_to_jiffies(timeout));
143
144 ps2_end_command(ps2dev);
145}
146EXPORT_SYMBOL(ps2_drain);
147
148/*
149 * ps2_is_keyboard_id() checks received ID byte against the list of
150 * known keyboard IDs.
151 */
152
153bool ps2_is_keyboard_id(u8 id_byte)
154{
155 static const u8 keyboard_ids[] = {
156 0xab, /* Regular keyboards */
157 0xac, /* NCD Sun keyboard */
158 0x2b, /* Trust keyboard, translated */
159 0x5d, /* Trust keyboard */
160 0x60, /* NMB SGI keyboard, translated */
161 0x47, /* NMB SGI keyboard */
162 };
163
164 return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
165}
166EXPORT_SYMBOL(ps2_is_keyboard_id);
167
168/*
169 * ps2_adjust_timeout() is called after receiving 1st byte of command
170 * response and tries to reduce remaining timeout to speed up command
171 * completion.
172 */
173
174static int ps2_adjust_timeout(struct ps2dev *ps2dev,
175 unsigned int command, unsigned int timeout)
176{
177 switch (command) {
178 case PS2_CMD_RESET_BAT:
179 /*
180 * Device has sent the first response byte after
181 * reset command, reset is thus done, so we can
182 * shorten the timeout.
183 * The next byte will come soon (keyboard) or not
184 * at all (mouse).
185 */
186 if (timeout > msecs_to_jiffies(100))
187 timeout = msecs_to_jiffies(100);
188 break;
189
190 case PS2_CMD_GETID:
191 /*
192 * Microsoft Natural Elite keyboard responds to
193 * the GET ID command as it were a mouse, with
194 * a single byte. Fail the command so atkbd will
195 * use alternative probe to detect it.
196 */
197 if (ps2dev->cmdbuf[1] == 0xaa) {
198 serio_pause_rx(ps2dev->serio);
199 ps2dev->flags = 0;
200 serio_continue_rx(ps2dev->serio);
201 timeout = 0;
202 }
203
204 /*
205 * If device behind the port is not a keyboard there
206 * won't be 2nd byte of ID response.
207 */
208 if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
209 serio_pause_rx(ps2dev->serio);
210 ps2dev->flags = ps2dev->cmdcnt = 0;
211 serio_continue_rx(ps2dev->serio);
212 timeout = 0;
213 }
214 break;
215
216 default:
217 break;
218 }
219
220 return timeout;
221}
222
223/*
224 * ps2_command() sends a command and its parameters to the mouse,
225 * then waits for the response and puts it in the param array.
226 *
227 * ps2_command() can only be called from a process context
228 */
229
230int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
231{
232 unsigned int timeout;
233 unsigned int send = (command >> 12) & 0xf;
234 unsigned int receive = (command >> 8) & 0xf;
235 int rc;
236 int i;
237 u8 send_param[16];
238
239 if (receive > sizeof(ps2dev->cmdbuf)) {
240 WARN_ON(1);
241 return -EINVAL;
242 }
243
244 if (send && !param) {
245 WARN_ON(1);
246 return -EINVAL;
247 }
248
249 memcpy(send_param, param, send);
250
251 serio_pause_rx(ps2dev->serio);
252
253 ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
254 ps2dev->cmdcnt = receive;
255 if (receive && param)
256 for (i = 0; i < receive; i++)
257 ps2dev->cmdbuf[(receive - 1) - i] = param[i];
258
259 /* Signal that we are sending the command byte */
260 ps2dev->flags |= PS2_FLAG_ACK_CMD;
261
262 /*
263 * Some devices (Synaptics) peform the reset before
264 * ACKing the reset command, and so it can take a long
265 * time before the ACK arrives.
266 */
267 timeout = command == PS2_CMD_RESET_BAT ? 1000 : 200;
268
269 rc = ps2_do_sendbyte(ps2dev, command & 0xff, timeout, 2);
270 if (rc)
271 goto out_reset_flags;
272
273 /* Now we are sending command parameters, if any */
274 ps2dev->flags &= ~PS2_FLAG_ACK_CMD;
275
276 for (i = 0; i < send; i++) {
277 rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2);
278 if (rc)
279 goto out_reset_flags;
280 }
281
282 serio_continue_rx(ps2dev->serio);
283
284 /*
285 * The reset command takes a long time to execute.
286 */
287 timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
288
289 timeout = wait_event_timeout(ps2dev->wait,
290 !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
291
292 if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
293
294 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
295 wait_event_timeout(ps2dev->wait,
296 !(ps2dev->flags & PS2_FLAG_CMD), timeout);
297 }
298
299 serio_pause_rx(ps2dev->serio);
300
301 if (param)
302 for (i = 0; i < receive; i++)
303 param[i] = ps2dev->cmdbuf[(receive - 1) - i];
304
305 if (ps2dev->cmdcnt &&
306 (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1)) {
307 rc = -EPROTO;
308 goto out_reset_flags;
309 }
310
311 rc = 0;
312
313 out_reset_flags:
314 ps2dev->flags = 0;
315 serio_continue_rx(ps2dev->serio);
316
317 dev_dbg(&ps2dev->serio->dev,
318 "%02x [%*ph] - %x/%08lx [%*ph]\n",
319 command & 0xff, send, send_param,
320 ps2dev->nak, ps2dev->flags,
321 receive, param ?: send_param);
322
323 /*
324 * ps_command() handles resends itself, so do not leak -EAGAIN
325 * to the callers.
326 */
327 return rc != -EAGAIN ? rc : -EPROTO;
328}
329EXPORT_SYMBOL(__ps2_command);
330
331int ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
332{
333 int rc;
334
335 ps2_begin_command(ps2dev);
336 rc = __ps2_command(ps2dev, param, command);
337 ps2_end_command(ps2dev);
338
339 return rc;
340}
341EXPORT_SYMBOL(ps2_command);
342
343/*
344 * ps2_sliced_command() sends an extended PS/2 command to the mouse
345 * using sliced syntax, understood by advanced devices, such as Logitech
346 * or Synaptics touchpads. The command is encoded as:
347 * 0xE6 0xE8 rr 0xE8 ss 0xE8 tt 0xE8 uu where (rr*64)+(ss*16)+(tt*4)+uu
348 * is the command.
349 */
350
351int ps2_sliced_command(struct ps2dev *ps2dev, u8 command)
352{
353 int i;
354 int retval;
355
356 ps2_begin_command(ps2dev);
357
358 retval = __ps2_command(ps2dev, NULL, PS2_CMD_SETSCALE11);
359 if (retval)
360 goto out;
361
362 for (i = 6; i >= 0; i -= 2) {
363 u8 d = (command >> i) & 3;
364 retval = __ps2_command(ps2dev, &d, PS2_CMD_SETRES);
365 if (retval)
366 break;
367 }
368
369out:
370 dev_dbg(&ps2dev->serio->dev, "%02x - %d\n", command, retval);
371 ps2_end_command(ps2dev);
372 return retval;
373}
374EXPORT_SYMBOL(ps2_sliced_command);
375
376/*
377 * ps2_init() initializes ps2dev structure
378 */
379
380void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
381{
382 mutex_init(&ps2dev->cmd_mutex);
383 lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
384 init_waitqueue_head(&ps2dev->wait);
385 ps2dev->serio = serio;
386}
387EXPORT_SYMBOL(ps2_init);
388
389/*
390 * ps2_handle_ack() is supposed to be used in interrupt handler
391 * to properly process ACK/NAK of a command from a PS/2 device.
392 */
393
394bool ps2_handle_ack(struct ps2dev *ps2dev, u8 data)
395{
396 switch (data) {
397 case PS2_RET_ACK:
398 ps2dev->nak = 0;
399 break;
400
401 case PS2_RET_NAK:
402 ps2dev->flags |= PS2_FLAG_NAK;
403 ps2dev->nak = PS2_RET_NAK;
404 break;
405
406 case PS2_RET_ERR:
407 if (ps2dev->flags & PS2_FLAG_NAK) {
408 ps2dev->flags &= ~PS2_FLAG_NAK;
409 ps2dev->nak = PS2_RET_ERR;
410 break;
411 }
412
413 /*
414 * Workaround for mice which don't ACK the Get ID command.
415 * These are valid mouse IDs that we recognize.
416 */
417 case 0x00:
418 case 0x03:
419 case 0x04:
420 if (ps2dev->flags & PS2_FLAG_WAITID) {
421 ps2dev->nak = 0;
422 break;
423 }
424 /* Fall through */
425 default:
426 /*
427 * Do not signal errors if we get unexpected reply while
428 * waiting for an ACK to the initial (first) command byte:
429 * the device might not be quiesced yet and continue
430 * delivering data.
431 * Note that we reset PS2_FLAG_WAITID flag, so the workaround
432 * for mice not acknowledging the Get ID command only triggers
433 * on the 1st byte; if device spews data we really want to see
434 * a real ACK from it.
435 */
436 dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data);
437 ps2dev->flags &= ~PS2_FLAG_WAITID;
438 return ps2dev->flags & PS2_FLAG_ACK_CMD;
439 }
440
441 if (!ps2dev->nak) {
442 ps2dev->flags &= ~PS2_FLAG_NAK;
443 if (ps2dev->cmdcnt)
444 ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
445 }
446
447 ps2dev->flags &= ~PS2_FLAG_ACK;
448 wake_up(&ps2dev->wait);
449
450 if (data != PS2_RET_ACK)
451 ps2_handle_response(ps2dev, data);
452
453 return true;
454}
455EXPORT_SYMBOL(ps2_handle_ack);
456
457/*
458 * ps2_handle_response() is supposed to be used in interrupt handler
459 * to properly store device's response to a command and notify process
460 * waiting for completion of the command.
461 */
462
463bool ps2_handle_response(struct ps2dev *ps2dev, u8 data)
464{
465 if (ps2dev->cmdcnt)
466 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
467
468 if (ps2dev->flags & PS2_FLAG_CMD1) {
469 ps2dev->flags &= ~PS2_FLAG_CMD1;
470 if (ps2dev->cmdcnt)
471 wake_up(&ps2dev->wait);
472 }
473
474 if (!ps2dev->cmdcnt) {
475 ps2dev->flags &= ~PS2_FLAG_CMD;
476 wake_up(&ps2dev->wait);
477 }
478
479 return true;
480}
481EXPORT_SYMBOL(ps2_handle_response);
482
483void ps2_cmd_aborted(struct ps2dev *ps2dev)
484{
485 if (ps2dev->flags & PS2_FLAG_ACK)
486 ps2dev->nak = 1;
487
488 if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
489 wake_up(&ps2dev->wait);
490
491 /* reset all flags except last nack */
492 ps2dev->flags &= PS2_FLAG_NAK;
493}
494EXPORT_SYMBOL(ps2_cmd_aborted);
495