Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-only
2 : /*
3 : * PS/2 driver library
4 : *
5 : * Copyright (c) 1999-2002 Vojtech Pavlik
6 : * Copyright (c) 2004 Dmitry Torokhov
7 : */
8 :
9 :
10 : #include <linux/delay.h>
11 : #include <linux/module.h>
12 : #include <linux/sched.h>
13 : #include <linux/interrupt.h>
14 : #include <linux/input.h>
15 : #include <linux/serio.h>
16 : #include <linux/i8042.h>
17 : #include <linux/libps2.h>
18 :
19 : #define DRIVER_DESC "PS/2 driver library"
20 :
21 : MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
22 : MODULE_DESCRIPTION("PS/2 driver library");
23 : MODULE_LICENSE("GPL");
24 :
25 0 : static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte,
26 : unsigned int timeout, unsigned int max_attempts)
27 : __releases(&ps2dev->serio->lock) __acquires(&ps2dev->serio->lock)
28 : {
29 0 : int attempt = 0;
30 : int error;
31 :
32 : lockdep_assert_held(&ps2dev->serio->lock);
33 :
34 : do {
35 0 : ps2dev->nak = 1;
36 0 : ps2dev->flags |= PS2_FLAG_ACK;
37 :
38 0 : serio_continue_rx(ps2dev->serio);
39 :
40 0 : error = serio_write(ps2dev->serio, byte);
41 0 : if (error)
42 : dev_dbg(&ps2dev->serio->dev,
43 : "failed to write %#02x: %d\n", byte, error);
44 : else
45 0 : wait_event_timeout(ps2dev->wait,
46 : !(ps2dev->flags & PS2_FLAG_ACK),
47 : msecs_to_jiffies(timeout));
48 :
49 0 : serio_pause_rx(ps2dev->serio);
50 0 : } while (ps2dev->nak == PS2_RET_NAK && ++attempt < max_attempts);
51 :
52 0 : ps2dev->flags &= ~PS2_FLAG_ACK;
53 :
54 0 : if (!error) {
55 0 : switch (ps2dev->nak) {
56 : case 0:
57 : break;
58 : case PS2_RET_NAK:
59 0 : error = -EAGAIN;
60 0 : break;
61 : case PS2_RET_ERR:
62 0 : error = -EPROTO;
63 0 : break;
64 : default:
65 0 : error = -EIO;
66 0 : break;
67 : }
68 : }
69 :
70 : if (error || attempt > 1)
71 : dev_dbg(&ps2dev->serio->dev,
72 : "%02x - %d (%x), attempt %d\n",
73 : byte, error, ps2dev->nak, attempt);
74 :
75 0 : return error;
76 : }
77 :
78 : /*
79 : * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
80 : * It doesn't handle retransmission, the caller is expected to handle
81 : * it when needed.
82 : *
83 : * ps2_sendbyte() can only be called from a process context.
84 : */
85 :
86 0 : int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
87 : {
88 : int retval;
89 :
90 0 : serio_pause_rx(ps2dev->serio);
91 :
92 0 : retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1);
93 : dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);
94 :
95 0 : serio_continue_rx(ps2dev->serio);
96 :
97 0 : return retval;
98 : }
99 : EXPORT_SYMBOL(ps2_sendbyte);
100 :
101 0 : void ps2_begin_command(struct ps2dev *ps2dev)
102 : {
103 0 : struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
104 :
105 0 : mutex_lock(m);
106 0 : }
107 : EXPORT_SYMBOL(ps2_begin_command);
108 :
109 0 : void ps2_end_command(struct ps2dev *ps2dev)
110 : {
111 0 : struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
112 :
113 0 : mutex_unlock(m);
114 0 : }
115 : EXPORT_SYMBOL(ps2_end_command);
116 :
117 : /*
118 : * ps2_drain() waits for device to transmit requested number of bytes
119 : * and discards them.
120 : */
121 :
122 0 : void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout)
123 : {
124 0 : if (maxbytes > sizeof(ps2dev->cmdbuf)) {
125 0 : WARN_ON(1);
126 0 : maxbytes = sizeof(ps2dev->cmdbuf);
127 : }
128 :
129 0 : ps2_begin_command(ps2dev);
130 :
131 0 : serio_pause_rx(ps2dev->serio);
132 0 : ps2dev->flags = PS2_FLAG_CMD;
133 0 : ps2dev->cmdcnt = maxbytes;
134 0 : serio_continue_rx(ps2dev->serio);
135 :
136 0 : wait_event_timeout(ps2dev->wait,
137 : !(ps2dev->flags & PS2_FLAG_CMD),
138 : msecs_to_jiffies(timeout));
139 :
140 0 : ps2_end_command(ps2dev);
141 0 : }
142 : EXPORT_SYMBOL(ps2_drain);
143 :
144 : /*
145 : * ps2_is_keyboard_id() checks received ID byte against the list of
146 : * known keyboard IDs.
147 : */
148 :
149 0 : bool ps2_is_keyboard_id(u8 id_byte)
150 : {
151 : static const u8 keyboard_ids[] = {
152 : 0xab, /* Regular keyboards */
153 : 0xac, /* NCD Sun keyboard */
154 : 0x2b, /* Trust keyboard, translated */
155 : 0x5d, /* Trust keyboard */
156 : 0x60, /* NMB SGI keyboard, translated */
157 : 0x47, /* NMB SGI keyboard */
158 : };
159 :
160 0 : return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
161 : }
162 : EXPORT_SYMBOL(ps2_is_keyboard_id);
163 :
164 : /*
165 : * ps2_adjust_timeout() is called after receiving 1st byte of command
166 : * response and tries to reduce remaining timeout to speed up command
167 : * completion.
168 : */
169 :
170 0 : static int ps2_adjust_timeout(struct ps2dev *ps2dev,
171 : unsigned int command, unsigned int timeout)
172 : {
173 0 : switch (command) {
174 : case PS2_CMD_RESET_BAT:
175 : /*
176 : * Device has sent the first response byte after
177 : * reset command, reset is thus done, so we can
178 : * shorten the timeout.
179 : * The next byte will come soon (keyboard) or not
180 : * at all (mouse).
181 : */
182 0 : if (timeout > msecs_to_jiffies(100))
183 0 : timeout = msecs_to_jiffies(100);
184 : break;
185 :
186 : case PS2_CMD_GETID:
187 : /*
188 : * Microsoft Natural Elite keyboard responds to
189 : * the GET ID command as it were a mouse, with
190 : * a single byte. Fail the command so atkbd will
191 : * use alternative probe to detect it.
192 : */
193 0 : if (ps2dev->cmdbuf[1] == 0xaa) {
194 0 : serio_pause_rx(ps2dev->serio);
195 0 : ps2dev->flags = 0;
196 0 : serio_continue_rx(ps2dev->serio);
197 0 : timeout = 0;
198 : }
199 :
200 : /*
201 : * If device behind the port is not a keyboard there
202 : * won't be 2nd byte of ID response.
203 : */
204 0 : if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
205 0 : serio_pause_rx(ps2dev->serio);
206 0 : ps2dev->flags = ps2dev->cmdcnt = 0;
207 0 : serio_continue_rx(ps2dev->serio);
208 0 : timeout = 0;
209 : }
210 : break;
211 :
212 : default:
213 : break;
214 : }
215 :
216 0 : return timeout;
217 : }
218 :
219 : /*
220 : * ps2_command() sends a command and its parameters to the mouse,
221 : * then waits for the response and puts it in the param array.
222 : *
223 : * ps2_command() can only be called from a process context
224 : */
225 :
226 0 : int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
227 : {
228 : unsigned int timeout;
229 0 : unsigned int send = (command >> 12) & 0xf;
230 0 : unsigned int receive = (command >> 8) & 0xf;
231 : int rc;
232 : int i;
233 : u8 send_param[16];
234 :
235 0 : if (receive > sizeof(ps2dev->cmdbuf)) {
236 0 : WARN_ON(1);
237 0 : return -EINVAL;
238 : }
239 :
240 0 : if (send && !param) {
241 0 : WARN_ON(1);
242 0 : return -EINVAL;
243 : }
244 :
245 0 : memcpy(send_param, param, send);
246 :
247 0 : serio_pause_rx(ps2dev->serio);
248 :
249 0 : ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
250 0 : ps2dev->cmdcnt = receive;
251 0 : if (receive && param)
252 0 : for (i = 0; i < receive; i++)
253 0 : ps2dev->cmdbuf[(receive - 1) - i] = param[i];
254 :
255 : /* Signal that we are sending the command byte */
256 0 : ps2dev->flags |= PS2_FLAG_ACK_CMD;
257 :
258 : /*
259 : * Some devices (Synaptics) peform the reset before
260 : * ACKing the reset command, and so it can take a long
261 : * time before the ACK arrives.
262 : */
263 0 : timeout = command == PS2_CMD_RESET_BAT ? 1000 : 200;
264 :
265 0 : rc = ps2_do_sendbyte(ps2dev, command & 0xff, timeout, 2);
266 0 : if (rc)
267 : goto out_reset_flags;
268 :
269 : /* Now we are sending command parameters, if any */
270 0 : ps2dev->flags &= ~PS2_FLAG_ACK_CMD;
271 :
272 0 : for (i = 0; i < send; i++) {
273 0 : rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2);
274 0 : if (rc)
275 : goto out_reset_flags;
276 : }
277 :
278 0 : serio_continue_rx(ps2dev->serio);
279 :
280 : /*
281 : * The reset command takes a long time to execute.
282 : */
283 0 : timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
284 :
285 0 : timeout = wait_event_timeout(ps2dev->wait,
286 : !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
287 :
288 0 : if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
289 :
290 0 : timeout = ps2_adjust_timeout(ps2dev, command, timeout);
291 0 : wait_event_timeout(ps2dev->wait,
292 : !(ps2dev->flags & PS2_FLAG_CMD), timeout);
293 : }
294 :
295 0 : serio_pause_rx(ps2dev->serio);
296 :
297 0 : if (param)
298 0 : for (i = 0; i < receive; i++)
299 0 : param[i] = ps2dev->cmdbuf[(receive - 1) - i];
300 :
301 0 : if (ps2dev->cmdcnt &&
302 0 : (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1)) {
303 : rc = -EPROTO;
304 : goto out_reset_flags;
305 : }
306 :
307 0 : rc = 0;
308 :
309 : out_reset_flags:
310 0 : ps2dev->flags = 0;
311 0 : serio_continue_rx(ps2dev->serio);
312 :
313 : dev_dbg(&ps2dev->serio->dev,
314 : "%02x [%*ph] - %x/%08lx [%*ph]\n",
315 : command & 0xff, send, send_param,
316 : ps2dev->nak, ps2dev->flags,
317 : receive, param ?: send_param);
318 :
319 : /*
320 : * ps_command() handles resends itself, so do not leak -EAGAIN
321 : * to the callers.
322 : */
323 0 : return rc != -EAGAIN ? rc : -EPROTO;
324 : }
325 : EXPORT_SYMBOL(__ps2_command);
326 :
327 0 : int ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
328 : {
329 : int rc;
330 :
331 0 : ps2_begin_command(ps2dev);
332 0 : rc = __ps2_command(ps2dev, param, command);
333 0 : ps2_end_command(ps2dev);
334 :
335 0 : return rc;
336 : }
337 : EXPORT_SYMBOL(ps2_command);
338 :
339 : /*
340 : * ps2_sliced_command() sends an extended PS/2 command to the mouse
341 : * using sliced syntax, understood by advanced devices, such as Logitech
342 : * or Synaptics touchpads. The command is encoded as:
343 : * 0xE6 0xE8 rr 0xE8 ss 0xE8 tt 0xE8 uu where (rr*64)+(ss*16)+(tt*4)+uu
344 : * is the command.
345 : */
346 :
347 0 : int ps2_sliced_command(struct ps2dev *ps2dev, u8 command)
348 : {
349 : int i;
350 : int retval;
351 :
352 0 : ps2_begin_command(ps2dev);
353 :
354 0 : retval = __ps2_command(ps2dev, NULL, PS2_CMD_SETSCALE11);
355 0 : if (retval)
356 : goto out;
357 :
358 0 : for (i = 6; i >= 0; i -= 2) {
359 0 : u8 d = (command >> i) & 3;
360 0 : retval = __ps2_command(ps2dev, &d, PS2_CMD_SETRES);
361 0 : if (retval)
362 : break;
363 : }
364 :
365 : out:
366 : dev_dbg(&ps2dev->serio->dev, "%02x - %d\n", command, retval);
367 0 : ps2_end_command(ps2dev);
368 0 : return retval;
369 : }
370 : EXPORT_SYMBOL(ps2_sliced_command);
371 :
372 : /*
373 : * ps2_init() initializes ps2dev structure
374 : */
375 :
376 0 : void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
377 : {
378 0 : mutex_init(&ps2dev->cmd_mutex);
379 : lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
380 0 : init_waitqueue_head(&ps2dev->wait);
381 0 : ps2dev->serio = serio;
382 0 : }
383 : EXPORT_SYMBOL(ps2_init);
384 :
385 : /*
386 : * ps2_handle_ack() is supposed to be used in interrupt handler
387 : * to properly process ACK/NAK of a command from a PS/2 device.
388 : */
389 :
390 0 : bool ps2_handle_ack(struct ps2dev *ps2dev, u8 data)
391 : {
392 0 : switch (data) {
393 : case PS2_RET_ACK:
394 0 : ps2dev->nak = 0;
395 0 : break;
396 :
397 : case PS2_RET_NAK:
398 0 : ps2dev->flags |= PS2_FLAG_NAK;
399 0 : ps2dev->nak = PS2_RET_NAK;
400 0 : break;
401 :
402 : case PS2_RET_ERR:
403 0 : if (ps2dev->flags & PS2_FLAG_NAK) {
404 0 : ps2dev->flags &= ~PS2_FLAG_NAK;
405 0 : ps2dev->nak = PS2_RET_ERR;
406 0 : break;
407 : }
408 : fallthrough;
409 :
410 : /*
411 : * Workaround for mice which don't ACK the Get ID command.
412 : * These are valid mouse IDs that we recognize.
413 : */
414 : case 0x00:
415 : case 0x03:
416 : case 0x04:
417 0 : if (ps2dev->flags & PS2_FLAG_WAITID) {
418 0 : ps2dev->nak = 0;
419 0 : break;
420 : }
421 : fallthrough;
422 : default:
423 : /*
424 : * Do not signal errors if we get unexpected reply while
425 : * waiting for an ACK to the initial (first) command byte:
426 : * the device might not be quiesced yet and continue
427 : * delivering data.
428 : * Note that we reset PS2_FLAG_WAITID flag, so the workaround
429 : * for mice not acknowledging the Get ID command only triggers
430 : * on the 1st byte; if device spews data we really want to see
431 : * a real ACK from it.
432 : */
433 : dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data);
434 0 : ps2dev->flags &= ~PS2_FLAG_WAITID;
435 0 : return ps2dev->flags & PS2_FLAG_ACK_CMD;
436 : }
437 :
438 0 : if (!ps2dev->nak) {
439 0 : ps2dev->flags &= ~PS2_FLAG_NAK;
440 0 : if (ps2dev->cmdcnt)
441 0 : ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
442 : }
443 :
444 0 : ps2dev->flags &= ~PS2_FLAG_ACK;
445 0 : wake_up(&ps2dev->wait);
446 :
447 0 : if (data != PS2_RET_ACK)
448 0 : ps2_handle_response(ps2dev, data);
449 :
450 : return true;
451 : }
452 : EXPORT_SYMBOL(ps2_handle_ack);
453 :
454 : /*
455 : * ps2_handle_response() is supposed to be used in interrupt handler
456 : * to properly store device's response to a command and notify process
457 : * waiting for completion of the command.
458 : */
459 :
460 0 : bool ps2_handle_response(struct ps2dev *ps2dev, u8 data)
461 : {
462 0 : if (ps2dev->cmdcnt)
463 0 : ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
464 :
465 0 : if (ps2dev->flags & PS2_FLAG_CMD1) {
466 0 : ps2dev->flags &= ~PS2_FLAG_CMD1;
467 0 : if (ps2dev->cmdcnt)
468 0 : wake_up(&ps2dev->wait);
469 : }
470 :
471 0 : if (!ps2dev->cmdcnt) {
472 0 : ps2dev->flags &= ~PS2_FLAG_CMD;
473 0 : wake_up(&ps2dev->wait);
474 : }
475 :
476 0 : return true;
477 : }
478 : EXPORT_SYMBOL(ps2_handle_response);
479 :
480 0 : void ps2_cmd_aborted(struct ps2dev *ps2dev)
481 : {
482 0 : if (ps2dev->flags & PS2_FLAG_ACK)
483 0 : ps2dev->nak = 1;
484 :
485 0 : if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
486 0 : wake_up(&ps2dev->wait);
487 :
488 : /* reset all flags except last nack */
489 0 : ps2dev->flags &= PS2_FLAG_NAK;
490 0 : }
491 : EXPORT_SYMBOL(ps2_cmd_aborted);
|
