GNU Linux-libre 4.14.266-gnu1
[releases.git] / drivers / input / serio / libps2.c
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
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
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
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
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
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
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
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
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
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
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
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
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);