Merge branch 'linus' into core/rcu
[linux-2.6] / 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/slab.h>
17 #include <linux/interrupt.h>
18 #include <linux/input.h>
19 #include <linux/serio.h>
20 #include <linux/init.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 /*
58  * ps2_drain() waits for device to transmit requested number of bytes
59  * and discards them.
60  */
61
62 void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
63 {
64         if (maxbytes > sizeof(ps2dev->cmdbuf)) {
65                 WARN_ON(1);
66                 maxbytes = sizeof(ps2dev->cmdbuf);
67         }
68
69         mutex_lock(&ps2dev->cmd_mutex);
70
71         serio_pause_rx(ps2dev->serio);
72         ps2dev->flags = PS2_FLAG_CMD;
73         ps2dev->cmdcnt = maxbytes;
74         serio_continue_rx(ps2dev->serio);
75
76         wait_event_timeout(ps2dev->wait,
77                            !(ps2dev->flags & PS2_FLAG_CMD),
78                            msecs_to_jiffies(timeout));
79         mutex_unlock(&ps2dev->cmd_mutex);
80 }
81 EXPORT_SYMBOL(ps2_drain);
82
83 /*
84  * ps2_is_keyboard_id() checks received ID byte against the list of
85  * known keyboard IDs.
86  */
87
88 int ps2_is_keyboard_id(char id_byte)
89 {
90         static const char keyboard_ids[] = {
91                 0xab,   /* Regular keyboards            */
92                 0xac,   /* NCD Sun keyboard             */
93                 0x2b,   /* Trust keyboard, translated   */
94                 0x5d,   /* Trust keyboard               */
95                 0x60,   /* NMB SGI keyboard, translated */
96                 0x47,   /* NMB SGI keyboard             */
97         };
98
99         return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
100 }
101 EXPORT_SYMBOL(ps2_is_keyboard_id);
102
103 /*
104  * ps2_adjust_timeout() is called after receiving 1st byte of command
105  * response and tries to reduce remaining timeout to speed up command
106  * completion.
107  */
108
109 static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
110 {
111         switch (command) {
112                 case PS2_CMD_RESET_BAT:
113                         /*
114                          * Device has sent the first response byte after
115                          * reset command, reset is thus done, so we can
116                          * shorten the timeout.
117                          * The next byte will come soon (keyboard) or not
118                          * at all (mouse).
119                          */
120                         if (timeout > msecs_to_jiffies(100))
121                                 timeout = msecs_to_jiffies(100);
122                         break;
123
124                 case PS2_CMD_GETID:
125                         /*
126                          * Microsoft Natural Elite keyboard responds to
127                          * the GET ID command as it were a mouse, with
128                          * a single byte. Fail the command so atkbd will
129                          * use alternative probe to detect it.
130                          */
131                         if (ps2dev->cmdbuf[1] == 0xaa) {
132                                 serio_pause_rx(ps2dev->serio);
133                                 ps2dev->flags = 0;
134                                 serio_continue_rx(ps2dev->serio);
135                                 timeout = 0;
136                         }
137
138                         /*
139                          * If device behind the port is not a keyboard there
140                          * won't be 2nd byte of ID response.
141                          */
142                         if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
143                                 serio_pause_rx(ps2dev->serio);
144                                 ps2dev->flags = ps2dev->cmdcnt = 0;
145                                 serio_continue_rx(ps2dev->serio);
146                                 timeout = 0;
147                         }
148                         break;
149
150                 default:
151                         break;
152         }
153
154         return timeout;
155 }
156
157 /*
158  * ps2_command() sends a command and its parameters to the mouse,
159  * then waits for the response and puts it in the param array.
160  *
161  * ps2_command() can only be called from a process context
162  */
163
164 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
165 {
166         int timeout;
167         int send = (command >> 12) & 0xf;
168         int receive = (command >> 8) & 0xf;
169         int rc = -1;
170         int i;
171
172         if (receive > sizeof(ps2dev->cmdbuf)) {
173                 WARN_ON(1);
174                 return -1;
175         }
176
177         if (send && !param) {
178                 WARN_ON(1);
179                 return -1;
180         }
181
182         mutex_lock(&ps2dev->cmd_mutex);
183
184         serio_pause_rx(ps2dev->serio);
185         ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
186         ps2dev->cmdcnt = receive;
187         if (receive && param)
188                 for (i = 0; i < receive; i++)
189                         ps2dev->cmdbuf[(receive - 1) - i] = param[i];
190         serio_continue_rx(ps2dev->serio);
191
192         /*
193          * Some devices (Synaptics) peform the reset before
194          * ACKing the reset command, and so it can take a long
195          * time before the ACK arrrives.
196          */
197         if (ps2_sendbyte(ps2dev, command & 0xff,
198                          command == PS2_CMD_RESET_BAT ? 1000 : 200))
199                 goto out;
200
201         for (i = 0; i < send; i++)
202                 if (ps2_sendbyte(ps2dev, param[i], 200))
203                         goto out;
204
205         /*
206          * The reset command takes a long time to execute.
207          */
208         timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
209
210         timeout = wait_event_timeout(ps2dev->wait,
211                                      !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
212
213         if (ps2dev->cmdcnt && timeout > 0) {
214
215                 timeout = ps2_adjust_timeout(ps2dev, command, timeout);
216                 wait_event_timeout(ps2dev->wait,
217                                    !(ps2dev->flags & PS2_FLAG_CMD), timeout);
218         }
219
220         if (param)
221                 for (i = 0; i < receive; i++)
222                         param[i] = ps2dev->cmdbuf[(receive - 1) - i];
223
224         if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
225                 goto out;
226
227         rc = 0;
228
229  out:
230         serio_pause_rx(ps2dev->serio);
231         ps2dev->flags = 0;
232         serio_continue_rx(ps2dev->serio);
233
234         mutex_unlock(&ps2dev->cmd_mutex);
235         return rc;
236 }
237 EXPORT_SYMBOL(ps2_command);
238
239 /*
240  * ps2_init() initializes ps2dev structure
241  */
242
243 void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
244 {
245         mutex_init(&ps2dev->cmd_mutex);
246         lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
247         init_waitqueue_head(&ps2dev->wait);
248         ps2dev->serio = serio;
249 }
250 EXPORT_SYMBOL(ps2_init);
251
252 /*
253  * ps2_handle_ack() is supposed to be used in interrupt handler
254  * to properly process ACK/NAK of a command from a PS/2 device.
255  */
256
257 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
258 {
259         switch (data) {
260                 case PS2_RET_ACK:
261                         ps2dev->nak = 0;
262                         break;
263
264                 case PS2_RET_NAK:
265                         ps2dev->nak = 1;
266                         break;
267
268                 /*
269                  * Workaround for mice which don't ACK the Get ID command.
270                  * These are valid mouse IDs that we recognize.
271                  */
272                 case 0x00:
273                 case 0x03:
274                 case 0x04:
275                         if (ps2dev->flags & PS2_FLAG_WAITID) {
276                                 ps2dev->nak = 0;
277                                 break;
278                         }
279                         /* Fall through */
280                 default:
281                         return 0;
282         }
283
284
285         if (!ps2dev->nak && ps2dev->cmdcnt)
286                 ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
287
288         ps2dev->flags &= ~PS2_FLAG_ACK;
289         wake_up(&ps2dev->wait);
290
291         if (data != PS2_RET_ACK)
292                 ps2_handle_response(ps2dev, data);
293
294         return 1;
295 }
296 EXPORT_SYMBOL(ps2_handle_ack);
297
298 /*
299  * ps2_handle_response() is supposed to be used in interrupt handler
300  * to properly store device's response to a command and notify process
301  * waiting for completion of the command.
302  */
303
304 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
305 {
306         if (ps2dev->cmdcnt)
307                 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
308
309         if (ps2dev->flags & PS2_FLAG_CMD1) {
310                 ps2dev->flags &= ~PS2_FLAG_CMD1;
311                 if (ps2dev->cmdcnt)
312                         wake_up(&ps2dev->wait);
313         }
314
315         if (!ps2dev->cmdcnt) {
316                 ps2dev->flags &= ~PS2_FLAG_CMD;
317                 wake_up(&ps2dev->wait);
318         }
319
320         return 1;
321 }
322 EXPORT_SYMBOL(ps2_handle_response);
323
324 void ps2_cmd_aborted(struct ps2dev *ps2dev)
325 {
326         if (ps2dev->flags & PS2_FLAG_ACK)
327                 ps2dev->nak = 1;
328
329         if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
330                 wake_up(&ps2dev->wait);
331
332         ps2dev->flags = 0;
333 }
334 EXPORT_SYMBOL(ps2_cmd_aborted);