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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/kmsan-checks.h>
16#include <linux/serio.h>
17#include <linux/i8042.h>
18#include <linux/libps2.h>
19
20#define DRIVER_DESC "PS/2 driver library"
21
22#define PS2_CMD_SETSCALE11 0x00e6
23#define PS2_CMD_SETRES 0x10e8
24#define PS2_CMD_EX_SETLEDS 0x20eb
25#define PS2_CMD_SETLEDS 0x10ed
26#define PS2_CMD_GETID 0x02f2
27#define PS2_CMD_SETREP 0x10f3 /* Set repeat rate/set report rate */
28#define PS2_CMD_RESET_BAT 0x02ff
29
30#define PS2_RET_BAT 0xaa
31#define PS2_RET_ID 0x00
32#define PS2_RET_ACK 0xfa
33#define PS2_RET_NAK 0xfe
34#define PS2_RET_ERR 0xfc
35
36#define PS2_FLAG_ACK BIT(0) /* Waiting for ACK/NAK */
37#define PS2_FLAG_CMD BIT(1) /* Waiting for a command to finish */
38#define PS2_FLAG_CMD1 BIT(2) /* Waiting for the first byte of command response */
39#define PS2_FLAG_WAITID BIT(3) /* Command executing is GET ID */
40#define PS2_FLAG_NAK BIT(4) /* Last transmission was NAKed */
41#define PS2_FLAG_PASS_NOACK BIT(5) /* Pass non-ACK byte to receive handler */
42
43static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte,
44 unsigned int timeout, unsigned int max_attempts)
45 __releases(&ps2dev->serio->lock) __acquires(&ps2dev->serio->lock)
46{
47 int attempt = 0;
48 int error;
49
50 lockdep_assert_held(&ps2dev->serio->lock);
51
52 do {
53 ps2dev->nak = 1;
54 ps2dev->flags |= PS2_FLAG_ACK;
55
56 serio_continue_rx(ps2dev->serio);
57
58 error = serio_write(ps2dev->serio, byte);
59 if (error)
60 dev_dbg(&ps2dev->serio->dev,
61 "failed to write %#02x: %d\n", byte, error);
62 else
63 wait_event_timeout(ps2dev->wait,
64 !(ps2dev->flags & PS2_FLAG_ACK),
65 msecs_to_jiffies(timeout));
66
67 serio_pause_rx(ps2dev->serio);
68 } while (ps2dev->nak == PS2_RET_NAK && ++attempt < max_attempts);
69
70 ps2dev->flags &= ~PS2_FLAG_ACK;
71
72 if (!error) {
73 switch (ps2dev->nak) {
74 case 0:
75 break;
76 case PS2_RET_NAK:
77 error = -EAGAIN;
78 break;
79 case PS2_RET_ERR:
80 error = -EPROTO;
81 break;
82 default:
83 error = -EIO;
84 break;
85 }
86 }
87
88 if (error || attempt > 1)
89 dev_dbg(&ps2dev->serio->dev,
90 "%02x - %d (%x), attempt %d\n",
91 byte, error, ps2dev->nak, attempt);
92
93 return error;
94}
95
96/**
97 * ps2_sendbyte - sends a byte to the device and wait for acknowledgement
98 * @ps2dev: a PS/2 device to send the data to
99 * @byte: data to be sent to the device
100 * @timeout: timeout for sending the data and receiving an acknowledge
101 *
102 * The function doesn't handle retransmission, the caller is expected to handle
103 * it when needed.
104 *
105 * ps2_sendbyte() can only be called from a process context.
106 */
107int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
108{
109 int retval;
110
111 serio_pause_rx(ps2dev->serio);
112
113 retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1);
114 dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);
115
116 serio_continue_rx(ps2dev->serio);
117
118 return retval;
119}
120EXPORT_SYMBOL(ps2_sendbyte);
121
122/**
123 * ps2_begin_command - mark beginning of execution of a complex command
124 * @ps2dev: a PS/2 device executing the command
125 *
126 * Serializes a complex/compound command. Once command is finished
127 * ps2_end_command() should be called.
128 */
129void ps2_begin_command(struct ps2dev *ps2dev)
130{
131 struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
132
133 mutex_lock(m);
134}
135EXPORT_SYMBOL(ps2_begin_command);
136
137/**
138 * ps2_end_command - mark end of execution of a complex command
139 * @ps2dev: a PS/2 device executing the command
140 */
141void ps2_end_command(struct ps2dev *ps2dev)
142{
143 struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
144
145 mutex_unlock(m);
146}
147EXPORT_SYMBOL(ps2_end_command);
148
149/**
150 * ps2_drain - waits for device to transmit requested number of bytes
151 * and discards them
152 * @ps2dev: the PS/2 device that should be drained
153 * @maxbytes: maximum number of bytes to be drained
154 * @timeout: time to drain the device
155 */
156void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout)
157{
158 if (maxbytes > sizeof(ps2dev->cmdbuf)) {
159 WARN_ON(1);
160 maxbytes = sizeof(ps2dev->cmdbuf);
161 }
162
163 ps2_begin_command(ps2dev);
164
165 serio_pause_rx(ps2dev->serio);
166 ps2dev->flags = PS2_FLAG_CMD;
167 ps2dev->cmdcnt = maxbytes;
168 serio_continue_rx(ps2dev->serio);
169
170 wait_event_timeout(ps2dev->wait,
171 !(ps2dev->flags & PS2_FLAG_CMD),
172 msecs_to_jiffies(timeout));
173
174 ps2_end_command(ps2dev);
175}
176EXPORT_SYMBOL(ps2_drain);
177
178/**
179 * ps2_is_keyboard_id - checks received ID byte against the list of
180 * known keyboard IDs
181 * @id_byte: data byte that should be checked
182 */
183bool ps2_is_keyboard_id(u8 id_byte)
184{
185 static const u8 keyboard_ids[] = {
186 0xab, /* Regular keyboards */
187 0xac, /* NCD Sun keyboard */
188 0x2b, /* Trust keyboard, translated */
189 0x5d, /* Trust keyboard */
190 0x60, /* NMB SGI keyboard, translated */
191 0x47, /* NMB SGI keyboard */
192 };
193
194 return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
195}
196EXPORT_SYMBOL(ps2_is_keyboard_id);
197
198/*
199 * ps2_adjust_timeout() is called after receiving 1st byte of command
200 * response and tries to reduce remaining timeout to speed up command
201 * completion.
202 */
203static int ps2_adjust_timeout(struct ps2dev *ps2dev,
204 unsigned int command, unsigned int timeout)
205{
206 switch (command) {
207 case PS2_CMD_RESET_BAT:
208 /*
209 * Device has sent the first response byte after
210 * reset command, reset is thus done, so we can
211 * shorten the timeout.
212 * The next byte will come soon (keyboard) or not
213 * at all (mouse).
214 */
215 if (timeout > msecs_to_jiffies(100))
216 timeout = msecs_to_jiffies(100);
217 break;
218
219 case PS2_CMD_GETID:
220 /*
221 * Microsoft Natural Elite keyboard responds to
222 * the GET ID command as it were a mouse, with
223 * a single byte. Fail the command so atkbd will
224 * use alternative probe to detect it.
225 */
226 if (ps2dev->cmdbuf[1] == 0xaa) {
227 serio_pause_rx(ps2dev->serio);
228 ps2dev->flags = 0;
229 serio_continue_rx(ps2dev->serio);
230 timeout = 0;
231 }
232
233 /*
234 * If device behind the port is not a keyboard there
235 * won't be 2nd byte of ID response.
236 */
237 if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
238 serio_pause_rx(ps2dev->serio);
239 ps2dev->flags = ps2dev->cmdcnt = 0;
240 serio_continue_rx(ps2dev->serio);
241 timeout = 0;
242 }
243 break;
244
245 default:
246 break;
247 }
248
249 return timeout;
250}
251
252/**
253 * __ps2_command - send a command to PS/2 device
254 * @ps2dev: the PS/2 device that should execute the command
255 * @param: a buffer containing parameters to be sent along with the command,
256 * or place where the results of the command execution will be deposited,
257 * or both
258 * @command: command word that encodes the command itself, as well as number of
259 * additional parameter bytes that should be sent to the device and expected
260 * length of the command response
261 *
262 * Not serialized. Callers should use ps2_begin_command() and ps2_end_command()
263 * to ensure proper serialization for complex commands.
264 */
265int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
266{
267 unsigned int timeout;
268 unsigned int send = (command >> 12) & 0xf;
269 unsigned int receive = (command >> 8) & 0xf;
270 int rc;
271 int i;
272 u8 send_param[16];
273
274 if (receive > sizeof(ps2dev->cmdbuf)) {
275 WARN_ON(1);
276 return -EINVAL;
277 }
278
279 if (send && !param) {
280 WARN_ON(1);
281 return -EINVAL;
282 }
283
284 memcpy(send_param, param, send);
285
286 serio_pause_rx(ps2dev->serio);
287
288 ps2dev->cmdcnt = receive;
289
290 switch (command) {
291 case PS2_CMD_GETID:
292 /*
293 * Some mice do not ACK the "get ID" command, prepare to
294 * handle this.
295 */
296 ps2dev->flags = PS2_FLAG_WAITID;
297 break;
298
299 case PS2_CMD_SETLEDS:
300 case PS2_CMD_EX_SETLEDS:
301 case PS2_CMD_SETREP:
302 ps2dev->flags = PS2_FLAG_PASS_NOACK;
303 break;
304
305 default:
306 ps2dev->flags = 0;
307 break;
308 }
309
310 if (receive) {
311 /* Indicate that we expect response to the command. */
312 ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
313 if (param)
314 for (i = 0; i < receive; i++)
315 ps2dev->cmdbuf[(receive - 1) - i] = param[i];
316 }
317
318 /*
319 * Some devices (Synaptics) perform the reset before
320 * ACKing the reset command, and so it can take a long
321 * time before the ACK arrives.
322 */
323 timeout = command == PS2_CMD_RESET_BAT ? 1000 : 200;
324
325 rc = ps2_do_sendbyte(ps2dev, command & 0xff, timeout, 2);
326 if (rc)
327 goto out_reset_flags;
328
329 /* Send command parameters, if any. */
330 for (i = 0; i < send; i++) {
331 rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2);
332 if (rc)
333 goto out_reset_flags;
334 }
335
336 serio_continue_rx(ps2dev->serio);
337
338 /*
339 * The reset command takes a long time to execute.
340 */
341 timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
342
343 timeout = wait_event_timeout(ps2dev->wait,
344 !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
345
346 if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
347
348 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
349 wait_event_timeout(ps2dev->wait,
350 !(ps2dev->flags & PS2_FLAG_CMD), timeout);
351 }
352
353 serio_pause_rx(ps2dev->serio);
354
355 if (param) {
356 for (i = 0; i < receive; i++)
357 param[i] = ps2dev->cmdbuf[(receive - 1) - i];
358 kmsan_unpoison_memory(param, receive);
359 }
360
361 if (ps2dev->cmdcnt &&
362 (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1)) {
363 rc = -EPROTO;
364 goto out_reset_flags;
365 }
366
367 rc = 0;
368
369 out_reset_flags:
370 ps2dev->flags = 0;
371 serio_continue_rx(ps2dev->serio);
372
373 dev_dbg(&ps2dev->serio->dev,
374 "%02x [%*ph] - %x/%08lx [%*ph]\n",
375 command & 0xff, send, send_param,
376 ps2dev->nak, ps2dev->flags,
377 receive, param ?: send_param);
378
379 /*
380 * ps_command() handles resends itself, so do not leak -EAGAIN
381 * to the callers.
382 */
383 return rc != -EAGAIN ? rc : -EPROTO;
384}
385EXPORT_SYMBOL(__ps2_command);
386
387/**
388 * ps2_command - send a command to PS/2 device
389 * @ps2dev: the PS/2 device that should execute the command
390 * @param: a buffer containing parameters to be sent along with the command,
391 * or place where the results of the command execution will be deposited,
392 * or both
393 * @command: command word that encodes the command itself, as well as number of
394 * additional parameter bytes that should be sent to the device and expected
395 * length of the command response
396 *
397 * Note: ps2_command() serializes the command execution so that only one
398 * command can be executed at a time for either individual port or the entire
399 * 8042 controller.
400 */
401int ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
402{
403 int rc;
404
405 ps2_begin_command(ps2dev);
406 rc = __ps2_command(ps2dev, param, command);
407 ps2_end_command(ps2dev);
408
409 return rc;
410}
411EXPORT_SYMBOL(ps2_command);
412
413/**
414 * ps2_sliced_command - sends an extended PS/2 command to a mouse
415 * @ps2dev: the PS/2 device that should execute the command
416 * @command: command byte
417 *
418 * The command is sent using "sliced" syntax understood by advanced devices,
419 * such as Logitech or Synaptics touchpads. The command is encoded as:
420 * 0xE6 0xE8 rr 0xE8 ss 0xE8 tt 0xE8 uu where (rr*64)+(ss*16)+(tt*4)+uu
421 * is the command.
422 */
423int ps2_sliced_command(struct ps2dev *ps2dev, u8 command)
424{
425 int i;
426 int retval;
427
428 ps2_begin_command(ps2dev);
429
430 retval = __ps2_command(ps2dev, NULL, PS2_CMD_SETSCALE11);
431 if (retval)
432 goto out;
433
434 for (i = 6; i >= 0; i -= 2) {
435 u8 d = (command >> i) & 3;
436 retval = __ps2_command(ps2dev, &d, PS2_CMD_SETRES);
437 if (retval)
438 break;
439 }
440
441out:
442 dev_dbg(&ps2dev->serio->dev, "%02x - %d\n", command, retval);
443 ps2_end_command(ps2dev);
444 return retval;
445}
446EXPORT_SYMBOL(ps2_sliced_command);
447
448/**
449 * ps2_init - initializes ps2dev structure
450 * @ps2dev: structure to be initialized
451 * @serio: serio port associated with the PS/2 device
452 * @pre_receive_handler: validation handler to check basic communication state
453 * @receive_handler: main protocol handler
454 *
455 * Prepares ps2dev structure for use in drivers for PS/2 devices.
456 */
457void ps2_init(struct ps2dev *ps2dev, struct serio *serio,
458 ps2_pre_receive_handler_t pre_receive_handler,
459 ps2_receive_handler_t receive_handler)
460{
461 ps2dev->pre_receive_handler = pre_receive_handler;
462 ps2dev->receive_handler = receive_handler;
463
464 mutex_init(&ps2dev->cmd_mutex);
465 lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
466 init_waitqueue_head(&ps2dev->wait);
467 ps2dev->serio = serio;
468 serio_set_drvdata(serio, ps2dev);
469}
470EXPORT_SYMBOL(ps2_init);
471
472/*
473 * ps2_handle_response() stores device's response to a command and notifies
474 * the process waiting for completion of the command. Note that there is a
475 * distinction between waiting for the first byte of the response, and
476 * waiting for subsequent bytes. It is done so that callers could shorten
477 * timeouts once first byte of response is received.
478 */
479static void ps2_handle_response(struct ps2dev *ps2dev, u8 data)
480{
481 if (ps2dev->cmdcnt)
482 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
483
484 if (ps2dev->flags & PS2_FLAG_CMD1) {
485 ps2dev->flags &= ~PS2_FLAG_CMD1;
486 if (ps2dev->cmdcnt)
487 wake_up(&ps2dev->wait);
488 }
489
490 if (!ps2dev->cmdcnt) {
491 ps2dev->flags &= ~PS2_FLAG_CMD;
492 wake_up(&ps2dev->wait);
493 }
494}
495
496/*
497 * ps2_handle_ack() processes ACK/NAK of a command from a PS/2 device,
498 * possibly applying workarounds for mice not acknowledging the "get ID"
499 * command.
500 */
501static void ps2_handle_ack(struct ps2dev *ps2dev, u8 data)
502{
503 switch (data) {
504 case PS2_RET_ACK:
505 ps2dev->nak = 0;
506 break;
507
508 case PS2_RET_NAK:
509 ps2dev->flags |= PS2_FLAG_NAK;
510 ps2dev->nak = PS2_RET_NAK;
511 break;
512
513 case PS2_RET_ERR:
514 if (ps2dev->flags & PS2_FLAG_NAK) {
515 ps2dev->flags &= ~PS2_FLAG_NAK;
516 ps2dev->nak = PS2_RET_ERR;
517 break;
518 }
519 fallthrough;
520
521 /*
522 * Workaround for mice which don't ACK the Get ID command.
523 * These are valid mouse IDs that we recognize.
524 */
525 case 0x00:
526 case 0x03:
527 case 0x04:
528 if (ps2dev->flags & PS2_FLAG_WAITID) {
529 ps2dev->nak = 0;
530 break;
531 }
532 fallthrough;
533 default:
534 /*
535 * Do not signal errors if we get unexpected reply while
536 * waiting for an ACK to the initial (first) command byte:
537 * the device might not be quiesced yet and continue
538 * delivering data. For certain commands (such as set leds and
539 * set repeat rate) that can be used during normal device
540 * operation, we even pass this data byte to the normal receive
541 * handler.
542 * Note that we reset PS2_FLAG_WAITID flag, so the workaround
543 * for mice not acknowledging the Get ID command only triggers
544 * on the 1st byte; if device spews data we really want to see
545 * a real ACK from it.
546 */
547 dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data);
548 if (ps2dev->flags & PS2_FLAG_PASS_NOACK)
549 ps2dev->receive_handler(ps2dev, data);
550 ps2dev->flags &= ~(PS2_FLAG_WAITID | PS2_FLAG_PASS_NOACK);
551 return;
552 }
553
554 if (!ps2dev->nak)
555 ps2dev->flags &= ~PS2_FLAG_NAK;
556
557 ps2dev->flags &= ~PS2_FLAG_ACK;
558
559 if (!ps2dev->nak && data != PS2_RET_ACK)
560 ps2_handle_response(ps2dev, data);
561 else
562 wake_up(&ps2dev->wait);
563}
564
565/*
566 * Clears state of PS/2 device after communication error by resetting majority
567 * of flags and waking up waiters, if any.
568 */
569static void ps2_cleanup(struct ps2dev *ps2dev)
570{
571 unsigned long old_flags = ps2dev->flags;
572
573 /* reset all flags except last nak */
574 ps2dev->flags &= PS2_FLAG_NAK;
575
576 if (old_flags & PS2_FLAG_ACK)
577 ps2dev->nak = 1;
578
579 if (old_flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
580 wake_up(&ps2dev->wait);
581}
582
583/**
584 * ps2_interrupt - common interrupt handler for PS/2 devices
585 * @serio: serio port for the device
586 * @data: a data byte received from the device
587 * @flags: flags such as %SERIO_PARITY or %SERIO_TIMEOUT indicating state of
588 * the data transfer
589 *
590 * ps2_interrupt() invokes pre-receive handler, optionally handles command
591 * acknowledgement and response from the device, and finally passes the data
592 * to the main protocol handler for future processing.
593 */
594irqreturn_t ps2_interrupt(struct serio *serio, u8 data, unsigned int flags) {
595 struct ps2dev *ps2dev = serio_get_drvdata(serio);
596 enum ps2_disposition rc;
597
598 rc = ps2dev->pre_receive_handler(ps2dev, data, flags);
599 switch (rc) {
600 case PS2_ERROR:
601 ps2_cleanup(ps2dev);
602 break;
603
604 case PS2_IGNORE:
605 break;
606
607 case PS2_PROCESS:
608 if (ps2dev->flags & PS2_FLAG_ACK)
609 ps2_handle_ack(ps2dev, data);
610 else if (ps2dev->flags & PS2_FLAG_CMD)
611 ps2_handle_response(ps2dev, data);
612 else
613 ps2dev->receive_handler(ps2dev, data);
614 break;
615 }
616
617 return IRQ_HANDLED;
618}
619EXPORT_SYMBOL(ps2_interrupt);
620
621MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
622MODULE_DESCRIPTION("PS/2 driver library");
623MODULE_LICENSE("GPL");
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/kmsan-checks.h>
16#include <linux/serio.h>
17#include <linux/i8042.h>
18#include <linux/libps2.h>
19
20#define DRIVER_DESC "PS/2 driver library"
21
22#define PS2_CMD_SETSCALE11 0x00e6
23#define PS2_CMD_SETRES 0x10e8
24#define PS2_CMD_EX_SETLEDS 0x20eb
25#define PS2_CMD_SETLEDS 0x10ed
26#define PS2_CMD_GETID 0x02f2
27#define PS2_CMD_SETREP 0x10f3 /* Set repeat rate/set report rate */
28#define PS2_CMD_RESET_BAT 0x02ff
29
30#define PS2_RET_BAT 0xaa
31#define PS2_RET_ID 0x00
32#define PS2_RET_ACK 0xfa
33#define PS2_RET_NAK 0xfe
34#define PS2_RET_ERR 0xfc
35
36#define PS2_FLAG_ACK BIT(0) /* Waiting for ACK/NAK */
37#define PS2_FLAG_CMD BIT(1) /* Waiting for a command to finish */
38#define PS2_FLAG_CMD1 BIT(2) /* Waiting for the first byte of command response */
39#define PS2_FLAG_WAITID BIT(3) /* Command executing is GET ID */
40#define PS2_FLAG_NAK BIT(4) /* Last transmission was NAKed */
41#define PS2_FLAG_PASS_NOACK BIT(5) /* Pass non-ACK byte to receive handler */
42
43static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte,
44 unsigned int timeout, unsigned int max_attempts)
45 __releases(&ps2dev->serio->lock) __acquires(&ps2dev->serio->lock)
46{
47 int attempt = 0;
48 int error;
49
50 lockdep_assert_held(&ps2dev->serio->lock);
51
52 do {
53 ps2dev->nak = 1;
54 ps2dev->flags |= PS2_FLAG_ACK;
55
56 serio_continue_rx(ps2dev->serio);
57
58 error = serio_write(ps2dev->serio, byte);
59 if (error)
60 dev_dbg(&ps2dev->serio->dev,
61 "failed to write %#02x: %d\n", byte, error);
62 else
63 wait_event_timeout(ps2dev->wait,
64 !(ps2dev->flags & PS2_FLAG_ACK),
65 msecs_to_jiffies(timeout));
66
67 serio_pause_rx(ps2dev->serio);
68 } while (ps2dev->nak == PS2_RET_NAK && ++attempt < max_attempts);
69
70 ps2dev->flags &= ~PS2_FLAG_ACK;
71
72 if (!error) {
73 switch (ps2dev->nak) {
74 case 0:
75 break;
76 case PS2_RET_NAK:
77 error = -EAGAIN;
78 break;
79 case PS2_RET_ERR:
80 error = -EPROTO;
81 break;
82 default:
83 error = -EIO;
84 break;
85 }
86 }
87
88 if (error || attempt > 1)
89 dev_dbg(&ps2dev->serio->dev,
90 "%02x - %d (%x), attempt %d\n",
91 byte, error, ps2dev->nak, attempt);
92
93 return error;
94}
95
96/**
97 * ps2_sendbyte - sends a byte to the device and wait for acknowledgement
98 * @ps2dev: a PS/2 device to send the data to
99 * @byte: data to be sent to the device
100 * @timeout: timeout for sending the data and receiving an acknowledge
101 *
102 * The function doesn't handle retransmission, the caller is expected to handle
103 * it when needed.
104 *
105 * ps2_sendbyte() can only be called from a process context.
106 */
107int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
108{
109 int retval;
110
111 guard(serio_pause_rx)(ps2dev->serio);
112
113 retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1);
114 dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);
115
116 return retval;
117}
118EXPORT_SYMBOL(ps2_sendbyte);
119
120/**
121 * ps2_begin_command - mark beginning of execution of a complex command
122 * @ps2dev: a PS/2 device executing the command
123 *
124 * Serializes a complex/compound command. Once command is finished
125 * ps2_end_command() should be called.
126 */
127void ps2_begin_command(struct ps2dev *ps2dev)
128{
129 struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
130
131 mutex_lock(m);
132}
133EXPORT_SYMBOL(ps2_begin_command);
134
135/**
136 * ps2_end_command - mark end of execution of a complex command
137 * @ps2dev: a PS/2 device executing the command
138 */
139void ps2_end_command(struct ps2dev *ps2dev)
140{
141 struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
142
143 mutex_unlock(m);
144}
145EXPORT_SYMBOL(ps2_end_command);
146
147/**
148 * ps2_drain - waits for device to transmit requested number of bytes
149 * and discards them
150 * @ps2dev: the PS/2 device that should be drained
151 * @maxbytes: maximum number of bytes to be drained
152 * @timeout: time to drain the device
153 */
154void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout)
155{
156 if (maxbytes > sizeof(ps2dev->cmdbuf)) {
157 WARN_ON(1);
158 maxbytes = sizeof(ps2dev->cmdbuf);
159 }
160
161 ps2_begin_command(ps2dev);
162
163 scoped_guard(serio_pause_rx, ps2dev->serio) {
164 ps2dev->flags = PS2_FLAG_CMD;
165 ps2dev->cmdcnt = maxbytes;
166 }
167
168 wait_event_timeout(ps2dev->wait,
169 !(ps2dev->flags & PS2_FLAG_CMD),
170 msecs_to_jiffies(timeout));
171
172 ps2_end_command(ps2dev);
173}
174EXPORT_SYMBOL(ps2_drain);
175
176/**
177 * ps2_is_keyboard_id - checks received ID byte against the list of
178 * known keyboard IDs
179 * @id_byte: data byte that should be checked
180 */
181bool ps2_is_keyboard_id(u8 id_byte)
182{
183 static const u8 keyboard_ids[] = {
184 0xab, /* Regular keyboards */
185 0xac, /* NCD Sun keyboard */
186 0x2b, /* Trust keyboard, translated */
187 0x5d, /* Trust keyboard */
188 0x60, /* NMB SGI keyboard, translated */
189 0x47, /* NMB SGI keyboard */
190 };
191
192 return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
193}
194EXPORT_SYMBOL(ps2_is_keyboard_id);
195
196/*
197 * ps2_adjust_timeout() is called after receiving 1st byte of command
198 * response and tries to reduce remaining timeout to speed up command
199 * completion.
200 */
201static int ps2_adjust_timeout(struct ps2dev *ps2dev,
202 unsigned int command, unsigned int timeout)
203{
204 switch (command) {
205 case PS2_CMD_RESET_BAT:
206 /*
207 * Device has sent the first response byte after
208 * reset command, reset is thus done, so we can
209 * shorten the timeout.
210 * The next byte will come soon (keyboard) or not
211 * at all (mouse).
212 */
213 if (timeout > msecs_to_jiffies(100))
214 timeout = msecs_to_jiffies(100);
215 break;
216
217 case PS2_CMD_GETID:
218 /*
219 * Microsoft Natural Elite keyboard responds to
220 * the GET ID command as it were a mouse, with
221 * a single byte. Fail the command so atkbd will
222 * use alternative probe to detect it.
223 */
224 if (ps2dev->cmdbuf[1] == 0xaa) {
225 scoped_guard(serio_pause_rx, ps2dev->serio)
226 ps2dev->flags = 0;
227
228 timeout = 0;
229 }
230
231 /*
232 * If device behind the port is not a keyboard there
233 * won't be 2nd byte of ID response.
234 */
235 if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
236 scoped_guard(serio_pause_rx, ps2dev->serio)
237 ps2dev->flags = ps2dev->cmdcnt = 0;
238
239 timeout = 0;
240 }
241 break;
242
243 default:
244 break;
245 }
246
247 return timeout;
248}
249
250/**
251 * __ps2_command - send a command to PS/2 device
252 * @ps2dev: the PS/2 device that should execute the command
253 * @param: a buffer containing parameters to be sent along with the command,
254 * or place where the results of the command execution will be deposited,
255 * or both
256 * @command: command word that encodes the command itself, as well as number of
257 * additional parameter bytes that should be sent to the device and expected
258 * length of the command response
259 *
260 * Not serialized. Callers should use ps2_begin_command() and ps2_end_command()
261 * to ensure proper serialization for complex commands.
262 */
263int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
264{
265 unsigned int timeout;
266 unsigned int send = (command >> 12) & 0xf;
267 unsigned int receive = (command >> 8) & 0xf;
268 int rc;
269 int i;
270 u8 send_param[16];
271
272 if (receive > sizeof(ps2dev->cmdbuf)) {
273 WARN_ON(1);
274 return -EINVAL;
275 }
276
277 if (send && !param) {
278 WARN_ON(1);
279 return -EINVAL;
280 }
281
282 memcpy(send_param, param, send);
283
284 /*
285 * Not using guard notation because we need to break critical
286 * section below while waiting for the response.
287 */
288 serio_pause_rx(ps2dev->serio);
289
290 ps2dev->cmdcnt = receive;
291
292 switch (command) {
293 case PS2_CMD_GETID:
294 /*
295 * Some mice do not ACK the "get ID" command, prepare to
296 * handle this.
297 */
298 ps2dev->flags = PS2_FLAG_WAITID;
299 break;
300
301 case PS2_CMD_SETLEDS:
302 case PS2_CMD_EX_SETLEDS:
303 case PS2_CMD_SETREP:
304 ps2dev->flags = PS2_FLAG_PASS_NOACK;
305 break;
306
307 default:
308 ps2dev->flags = 0;
309 break;
310 }
311
312 if (receive) {
313 /* Indicate that we expect response to the command. */
314 ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
315 if (param)
316 for (i = 0; i < receive; i++)
317 ps2dev->cmdbuf[(receive - 1) - i] = param[i];
318 }
319
320 /*
321 * Some devices (Synaptics) perform the reset before
322 * ACKing the reset command, and so it can take a long
323 * time before the ACK arrives.
324 */
325 timeout = command == PS2_CMD_RESET_BAT ? 1000 : 200;
326
327 rc = ps2_do_sendbyte(ps2dev, command & 0xff, timeout, 2);
328 if (rc)
329 goto out_reset_flags;
330
331 /* Send command parameters, if any. */
332 for (i = 0; i < send; i++) {
333 rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2);
334 if (rc)
335 goto out_reset_flags;
336 }
337
338 serio_continue_rx(ps2dev->serio);
339
340 /*
341 * The reset command takes a long time to execute.
342 */
343 timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
344
345 timeout = wait_event_timeout(ps2dev->wait,
346 !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
347
348 if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
349
350 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
351 wait_event_timeout(ps2dev->wait,
352 !(ps2dev->flags & PS2_FLAG_CMD), timeout);
353 }
354
355 serio_pause_rx(ps2dev->serio);
356
357 if (param) {
358 for (i = 0; i < receive; i++)
359 param[i] = ps2dev->cmdbuf[(receive - 1) - i];
360 kmsan_unpoison_memory(param, receive);
361 }
362
363 if (ps2dev->cmdcnt &&
364 (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1)) {
365 rc = -EPROTO;
366 goto out_reset_flags;
367 }
368
369 rc = 0;
370
371 out_reset_flags:
372 ps2dev->flags = 0;
373 serio_continue_rx(ps2dev->serio);
374
375 dev_dbg(&ps2dev->serio->dev,
376 "%02x [%*ph] - %x/%08lx [%*ph]\n",
377 command & 0xff, send, send_param,
378 ps2dev->nak, ps2dev->flags,
379 receive, param ?: send_param);
380
381 /*
382 * ps_command() handles resends itself, so do not leak -EAGAIN
383 * to the callers.
384 */
385 return rc != -EAGAIN ? rc : -EPROTO;
386}
387EXPORT_SYMBOL(__ps2_command);
388
389/**
390 * ps2_command - send a command to PS/2 device
391 * @ps2dev: the PS/2 device that should execute the command
392 * @param: a buffer containing parameters to be sent along with the command,
393 * or place where the results of the command execution will be deposited,
394 * or both
395 * @command: command word that encodes the command itself, as well as number of
396 * additional parameter bytes that should be sent to the device and expected
397 * length of the command response
398 *
399 * Note: ps2_command() serializes the command execution so that only one
400 * command can be executed at a time for either individual port or the entire
401 * 8042 controller.
402 */
403int ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
404{
405 int rc;
406
407 ps2_begin_command(ps2dev);
408 rc = __ps2_command(ps2dev, param, command);
409 ps2_end_command(ps2dev);
410
411 return rc;
412}
413EXPORT_SYMBOL(ps2_command);
414
415/**
416 * ps2_sliced_command - sends an extended PS/2 command to a mouse
417 * @ps2dev: the PS/2 device that should execute the command
418 * @command: command byte
419 *
420 * The command is sent using "sliced" syntax understood by advanced devices,
421 * such as Logitech or Synaptics touchpads. The command is encoded as:
422 * 0xE6 0xE8 rr 0xE8 ss 0xE8 tt 0xE8 uu where (rr*64)+(ss*16)+(tt*4)+uu
423 * is the command.
424 */
425int ps2_sliced_command(struct ps2dev *ps2dev, u8 command)
426{
427 int i;
428 int retval;
429
430 ps2_begin_command(ps2dev);
431
432 retval = __ps2_command(ps2dev, NULL, PS2_CMD_SETSCALE11);
433 if (retval)
434 goto out;
435
436 for (i = 6; i >= 0; i -= 2) {
437 u8 d = (command >> i) & 3;
438 retval = __ps2_command(ps2dev, &d, PS2_CMD_SETRES);
439 if (retval)
440 break;
441 }
442
443out:
444 dev_dbg(&ps2dev->serio->dev, "%02x - %d\n", command, retval);
445 ps2_end_command(ps2dev);
446 return retval;
447}
448EXPORT_SYMBOL(ps2_sliced_command);
449
450/**
451 * ps2_init - initializes ps2dev structure
452 * @ps2dev: structure to be initialized
453 * @serio: serio port associated with the PS/2 device
454 * @pre_receive_handler: validation handler to check basic communication state
455 * @receive_handler: main protocol handler
456 *
457 * Prepares ps2dev structure for use in drivers for PS/2 devices.
458 */
459void ps2_init(struct ps2dev *ps2dev, struct serio *serio,
460 ps2_pre_receive_handler_t pre_receive_handler,
461 ps2_receive_handler_t receive_handler)
462{
463 ps2dev->pre_receive_handler = pre_receive_handler;
464 ps2dev->receive_handler = receive_handler;
465
466 mutex_init(&ps2dev->cmd_mutex);
467 lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
468 init_waitqueue_head(&ps2dev->wait);
469 ps2dev->serio = serio;
470 serio_set_drvdata(serio, ps2dev);
471}
472EXPORT_SYMBOL(ps2_init);
473
474/*
475 * ps2_handle_response() stores device's response to a command and notifies
476 * the process waiting for completion of the command. Note that there is a
477 * distinction between waiting for the first byte of the response, and
478 * waiting for subsequent bytes. It is done so that callers could shorten
479 * timeouts once first byte of response is received.
480 */
481static void ps2_handle_response(struct ps2dev *ps2dev, u8 data)
482{
483 if (ps2dev->cmdcnt)
484 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
485
486 if (ps2dev->flags & PS2_FLAG_CMD1) {
487 ps2dev->flags &= ~PS2_FLAG_CMD1;
488 if (ps2dev->cmdcnt)
489 wake_up(&ps2dev->wait);
490 }
491
492 if (!ps2dev->cmdcnt) {
493 ps2dev->flags &= ~PS2_FLAG_CMD;
494 wake_up(&ps2dev->wait);
495 }
496}
497
498/*
499 * ps2_handle_ack() processes ACK/NAK of a command from a PS/2 device,
500 * possibly applying workarounds for mice not acknowledging the "get ID"
501 * command.
502 */
503static void ps2_handle_ack(struct ps2dev *ps2dev, u8 data)
504{
505 switch (data) {
506 case PS2_RET_ACK:
507 ps2dev->nak = 0;
508 break;
509
510 case PS2_RET_NAK:
511 ps2dev->flags |= PS2_FLAG_NAK;
512 ps2dev->nak = PS2_RET_NAK;
513 break;
514
515 case PS2_RET_ERR:
516 if (ps2dev->flags & PS2_FLAG_NAK) {
517 ps2dev->flags &= ~PS2_FLAG_NAK;
518 ps2dev->nak = PS2_RET_ERR;
519 break;
520 }
521 fallthrough;
522
523 /*
524 * Workaround for mice which don't ACK the Get ID command.
525 * These are valid mouse IDs that we recognize.
526 */
527 case 0x00:
528 case 0x03:
529 case 0x04:
530 if (ps2dev->flags & PS2_FLAG_WAITID) {
531 ps2dev->nak = 0;
532 break;
533 }
534 fallthrough;
535 default:
536 /*
537 * Do not signal errors if we get unexpected reply while
538 * waiting for an ACK to the initial (first) command byte:
539 * the device might not be quiesced yet and continue
540 * delivering data. For certain commands (such as set leds and
541 * set repeat rate) that can be used during normal device
542 * operation, we even pass this data byte to the normal receive
543 * handler.
544 * Note that we reset PS2_FLAG_WAITID flag, so the workaround
545 * for mice not acknowledging the Get ID command only triggers
546 * on the 1st byte; if device spews data we really want to see
547 * a real ACK from it.
548 */
549 dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data);
550 if (ps2dev->flags & PS2_FLAG_PASS_NOACK)
551 ps2dev->receive_handler(ps2dev, data);
552 ps2dev->flags &= ~(PS2_FLAG_WAITID | PS2_FLAG_PASS_NOACK);
553 return;
554 }
555
556 if (!ps2dev->nak)
557 ps2dev->flags &= ~PS2_FLAG_NAK;
558
559 ps2dev->flags &= ~PS2_FLAG_ACK;
560
561 if (!ps2dev->nak && data != PS2_RET_ACK)
562 ps2_handle_response(ps2dev, data);
563 else
564 wake_up(&ps2dev->wait);
565}
566
567/*
568 * Clears state of PS/2 device after communication error by resetting majority
569 * of flags and waking up waiters, if any.
570 */
571static void ps2_cleanup(struct ps2dev *ps2dev)
572{
573 unsigned long old_flags = ps2dev->flags;
574
575 /* reset all flags except last nak */
576 ps2dev->flags &= PS2_FLAG_NAK;
577
578 if (old_flags & PS2_FLAG_ACK)
579 ps2dev->nak = 1;
580
581 if (old_flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
582 wake_up(&ps2dev->wait);
583}
584
585/**
586 * ps2_interrupt - common interrupt handler for PS/2 devices
587 * @serio: serio port for the device
588 * @data: a data byte received from the device
589 * @flags: flags such as %SERIO_PARITY or %SERIO_TIMEOUT indicating state of
590 * the data transfer
591 *
592 * ps2_interrupt() invokes pre-receive handler, optionally handles command
593 * acknowledgement and response from the device, and finally passes the data
594 * to the main protocol handler for future processing.
595 */
596irqreturn_t ps2_interrupt(struct serio *serio, u8 data, unsigned int flags) {
597 struct ps2dev *ps2dev = serio_get_drvdata(serio);
598 enum ps2_disposition rc;
599
600 rc = ps2dev->pre_receive_handler(ps2dev, data, flags);
601 switch (rc) {
602 case PS2_ERROR:
603 ps2_cleanup(ps2dev);
604 break;
605
606 case PS2_IGNORE:
607 break;
608
609 case PS2_PROCESS:
610 if (ps2dev->flags & PS2_FLAG_ACK)
611 ps2_handle_ack(ps2dev, data);
612 else if (ps2dev->flags & PS2_FLAG_CMD)
613 ps2_handle_response(ps2dev, data);
614 else
615 ps2dev->receive_handler(ps2dev, data);
616 break;
617 }
618
619 return IRQ_HANDLED;
620}
621EXPORT_SYMBOL(ps2_interrupt);
622
623MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
624MODULE_DESCRIPTION("PS/2 driver library");
625MODULE_LICENSE("GPL");