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 && !(ps2dev->flags & PS2_FLAG_CMD1)) {
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->flags |= PS2_FLAG_NAK;
266 ps2dev->nak = PS2_RET_NAK;
267 break;
268
269 case PS2_RET_ERR:
270 if (ps2dev->flags & PS2_FLAG_NAK) {
271 ps2dev->flags &= ~PS2_FLAG_NAK;
272 ps2dev->nak = PS2_RET_ERR;
273 break;
274 }
275
276 /*
277 * Workaround for mice which don't ACK the Get ID command.
278 * These are valid mouse IDs that we recognize.
279 */
280 case 0x00:
281 case 0x03:
282 case 0x04:
283 if (ps2dev->flags & PS2_FLAG_WAITID) {
284 ps2dev->nak = 0;
285 break;
286 }
287 /* Fall through */
288 default:
289 return 0;
290 }
291
292
293 if (!ps2dev->nak) {
294 ps2dev->flags &= ~PS2_FLAG_NAK;
295 if (ps2dev->cmdcnt)
296 ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
297 }
298
299 ps2dev->flags &= ~PS2_FLAG_ACK;
300 wake_up(&ps2dev->wait);
301
302 if (data != PS2_RET_ACK)
303 ps2_handle_response(ps2dev, data);
304
305 return 1;
306 }
307 EXPORT_SYMBOL(ps2_handle_ack);
308
309 /*
310 * ps2_handle_response() is supposed to be used in interrupt handler
311 * to properly store device's response to a command and notify process
312 * waiting for completion of the command.
313 */
314
315 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
316 {
317 if (ps2dev->cmdcnt)
318 ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
319
320 if (ps2dev->flags & PS2_FLAG_CMD1) {
321 ps2dev->flags &= ~PS2_FLAG_CMD1;
322 if (ps2dev->cmdcnt)
323 wake_up(&ps2dev->wait);
324 }
325
326 if (!ps2dev->cmdcnt) {
327 ps2dev->flags &= ~PS2_FLAG_CMD;
328 wake_up(&ps2dev->wait);
329 }
330
331 return 1;
332 }
333 EXPORT_SYMBOL(ps2_handle_response);
334
335 void ps2_cmd_aborted(struct ps2dev *ps2dev)
336 {
337 if (ps2dev->flags & PS2_FLAG_ACK)
338 ps2dev->nak = 1;
339
340 if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
341 wake_up(&ps2dev->wait);
342
343 /* reset all flags except last nack */
344 ps2dev->flags &= PS2_FLAG_NAK;
345 }
346 EXPORT_SYMBOL(ps2_cmd_aborted);
347
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