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/moduleparam.h>
17#include <linux/slab.h>
18#include <linux/interrupt.h>
19#include <linux/input.h>
20#include <linux/serio.h>
21#include <linux/init.h>
22#include <linux/libps2.h>
23
24#define DRIVER_DESC	"PS/2 driver library"
25
26MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
27MODULE_DESCRIPTION("PS/2 driver library");
28MODULE_LICENSE("GPL");
29
30/* Work structure to schedule execution of a command */
31struct ps2work {
32	struct work_struct work;
33	struct ps2dev *ps2dev;
34	int command;
35	unsigned char param[0];
36};
37
38
39/*
40 * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
41 * It doesn't handle retransmission, though it could - because if there
42 * is a need for retransmissions device has to be replaced anyway.
43 *
44 * ps2_sendbyte() can only be called from a process context.
45 */
46
47int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
48{
49	serio_pause_rx(ps2dev->serio);
50	ps2dev->nak = 1;
51	ps2dev->flags |= PS2_FLAG_ACK;
52	serio_continue_rx(ps2dev->serio);
53
54	if (serio_write(ps2dev->serio, byte) == 0)
55		wait_event_timeout(ps2dev->wait,
56				   !(ps2dev->flags & PS2_FLAG_ACK),
57				   msecs_to_jiffies(timeout));
58
59	serio_pause_rx(ps2dev->serio);
60	ps2dev->flags &= ~PS2_FLAG_ACK;
61	serio_continue_rx(ps2dev->serio);
62
63	return -ps2dev->nak;
64}
65EXPORT_SYMBOL(ps2_sendbyte);
66
67/*
68 * ps2_drain() waits for device to transmit requested number of bytes
69 * and discards them.
70 */
71
72void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
73{
74	if (maxbytes > sizeof(ps2dev->cmdbuf)) {
75		WARN_ON(1);
76		maxbytes = sizeof(ps2dev->cmdbuf);
77	}
78
79	mutex_lock(&ps2dev->cmd_mutex);
80
81	serio_pause_rx(ps2dev->serio);
82	ps2dev->flags = PS2_FLAG_CMD;
83	ps2dev->cmdcnt = maxbytes;
84	serio_continue_rx(ps2dev->serio);
85
86	wait_event_timeout(ps2dev->wait,
87			   !(ps2dev->flags & PS2_FLAG_CMD),
88			   msecs_to_jiffies(timeout));
89	mutex_unlock(&ps2dev->cmd_mutex);
90}
91EXPORT_SYMBOL(ps2_drain);
92
93/*
94 * ps2_is_keyboard_id() checks received ID byte against the list of
95 * known keyboard IDs.
96 */
97
98int ps2_is_keyboard_id(char id_byte)
99{
100	static const char keyboard_ids[] = {
101		0xab,	/* Regular keyboards		*/
102		0xac,	/* NCD Sun keyboard		*/
103		0x2b,	/* Trust keyboard, translated	*/
104		0x5d,	/* Trust keyboard		*/
105		0x60,	/* NMB SGI keyboard, translated */
106		0x47,	/* NMB SGI keyboard		*/
107	};
108
109	return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
110}
111EXPORT_SYMBOL(ps2_is_keyboard_id);
112
113/*
114 * ps2_adjust_timeout() is called after receiving 1st byte of command
115 * response and tries to reduce remaining timeout to speed up command
116 * completion.
117 */
118
119static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
120{
121	switch (command) {
122		case PS2_CMD_RESET_BAT:
123			/*
124			 * Device has sent the first response byte after
125			 * reset command, reset is thus done, so we can
126			 * shorten the timeout.
127			 * The next byte will come soon (keyboard) or not
128			 * at all (mouse).
129			 */
130			if (timeout > msecs_to_jiffies(100))
131				timeout = msecs_to_jiffies(100);
132			break;
133
134		case PS2_CMD_GETID:
135			/*
136			 * Microsoft Natural Elite keyboard responds to
137			 * the GET ID command as it were a mouse, with
138			 * a single byte. Fail the command so atkbd will
139			 * use alternative probe to detect it.
140			 */
141			if (ps2dev->cmdbuf[1] == 0xaa) {
142				serio_pause_rx(ps2dev->serio);
143				ps2dev->flags = 0;
144				serio_continue_rx(ps2dev->serio);
145				timeout = 0;
146			}
147
148			/*
149			 * If device behind the port is not a keyboard there
150			 * won't be 2nd byte of ID response.
151			 */
152			if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
153				serio_pause_rx(ps2dev->serio);
154				ps2dev->flags = ps2dev->cmdcnt = 0;
155				serio_continue_rx(ps2dev->serio);
156				timeout = 0;
157			}
158			break;
159
160		default:
161			break;
162	}
163
164	return timeout;
165}
166
167/*
168 * ps2_command() sends a command and its parameters to the mouse,
169 * then waits for the response and puts it in the param array.
170 *
171 * ps2_command() can only be called from a process context
172 */
173
174int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
175{
176	int timeout;
177	int send = (command >> 12) & 0xf;
178	int receive = (command >> 8) & 0xf;
179	int rc = -1;
180	int i;
181
182	if (receive > sizeof(ps2dev->cmdbuf)) {
183		WARN_ON(1);
184		return -1;
185	}
186
187	if (send && !param) {
188		WARN_ON(1);
189		return -1;
190	}
191
192	mutex_lock(&ps2dev->cmd_mutex);
193
194	serio_pause_rx(ps2dev->serio);
195	ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
196	ps2dev->cmdcnt = receive;
197	if (receive && param)
198		for (i = 0; i < receive; i++)
199			ps2dev->cmdbuf[(receive - 1) - i] = param[i];
200	serio_continue_rx(ps2dev->serio);
201
202	/*
203	 * Some devices (Synaptics) peform the reset before
204	 * ACKing the reset command, and so it can take a long
205	 * time before the ACK arrrives.
206	 */
207	if (ps2_sendbyte(ps2dev, command & 0xff,
208			 command == PS2_CMD_RESET_BAT ? 1000 : 200))
209		goto out;
210
211	for (i = 0; i < send; i++)
212		if (ps2_sendbyte(ps2dev, param[i], 200))
213			goto out;
214
215	/*
216	 * The reset command takes a long time to execute.
217	 */
218	timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
219
220	timeout = wait_event_timeout(ps2dev->wait,
221				     !(ps2dev->flags & PS2_FLAG_CMD1), timeout);
222
223	if (ps2dev->cmdcnt && timeout > 0) {
224
225		timeout = ps2_adjust_timeout(ps2dev, command, timeout);
226		wait_event_timeout(ps2dev->wait,
227				   !(ps2dev->flags & PS2_FLAG_CMD), timeout);
228	}
229
230	if (param)
231		for (i = 0; i < receive; i++)
232			param[i] = ps2dev->cmdbuf[(receive - 1) - i];
233
234	if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
235		goto out;
236
237	rc = 0;
238
239 out:
240	serio_pause_rx(ps2dev->serio);
241	ps2dev->flags = 0;
242	serio_continue_rx(ps2dev->serio);
243
244	mutex_unlock(&ps2dev->cmd_mutex);
245	return rc;
246}
247EXPORT_SYMBOL(ps2_command);
248
249/*
250 * ps2_execute_scheduled_command() sends a command, previously scheduled by
251 * ps2_schedule_command(), to a PS/2 device (keyboard, mouse, etc.)
252 */
253
254static void ps2_execute_scheduled_command(struct work_struct *work)
255{
256	struct ps2work *ps2work = container_of(work, struct ps2work, work);
257
258	ps2_command(ps2work->ps2dev, ps2work->param, ps2work->command);
259	kfree(ps2work);
260}
261
262/*
263 * ps2_schedule_command() allows to schedule delayed execution of a PS/2
264 * command and can be used to issue a command from an interrupt or softirq
265 * context.
266 */
267
268int ps2_schedule_command(struct ps2dev *ps2dev, unsigned char *param, int command)
269{
270	struct ps2work *ps2work;
271	int send = (command >> 12) & 0xf;
272	int receive = (command >> 8) & 0xf;
273
274	if (!(ps2work = kmalloc(sizeof(struct ps2work) + max(send, receive), GFP_ATOMIC)))
275		return -1;
276
277	memset(ps2work, 0, sizeof(struct ps2work));
278	ps2work->ps2dev = ps2dev;
279	ps2work->command = command;
280	memcpy(ps2work->param, param, send);
281	INIT_WORK(&ps2work->work, ps2_execute_scheduled_command);
282
283	if (!schedule_work(&ps2work->work)) {
284		kfree(ps2work);
285		return -1;
286	}
287
288	return 0;
289}
290EXPORT_SYMBOL(ps2_schedule_command);
291
292/*
293 * ps2_init() initializes ps2dev structure
294 */
295
296void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
297{
298	mutex_init(&ps2dev->cmd_mutex);
299	lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
300	init_waitqueue_head(&ps2dev->wait);
301	ps2dev->serio = serio;
302}
303EXPORT_SYMBOL(ps2_init);
304
305/*
306 * ps2_handle_ack() is supposed to be used in interrupt handler
307 * to properly process ACK/NAK of a command from a PS/2 device.
308 */
309
310int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
311{
312	switch (data) {
313		case PS2_RET_ACK:
314			ps2dev->nak = 0;
315			break;
316
317		case PS2_RET_NAK:
318			ps2dev->nak = 1;
319			break;
320
321		case 0x00:
322		case 0x03:
323		case 0x04:
324			if (ps2dev->flags & PS2_FLAG_WAITID) {
325				ps2dev->nak = 0;
326				break;
327			}
328			/* Fall through */
329		default:
330			return 0;
331	}
332
333
334	if (!ps2dev->nak && ps2dev->cmdcnt)
335		ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
336
337	ps2dev->flags &= ~PS2_FLAG_ACK;
338	wake_up(&ps2dev->wait);
339
340	if (data != PS2_RET_ACK)
341		ps2_handle_response(ps2dev, data);
342
343	return 1;
344}
345EXPORT_SYMBOL(ps2_handle_ack);
346
347/*
348 * ps2_handle_response() is supposed to be used in interrupt handler
349 * to properly store device's response to a command and notify process
350 * waiting for completion of the command.
351 */
352
353int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
354{
355	if (ps2dev->cmdcnt)
356		ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
357
358	if (ps2dev->flags & PS2_FLAG_CMD1) {
359		ps2dev->flags &= ~PS2_FLAG_CMD1;
360		if (ps2dev->cmdcnt)
361			wake_up(&ps2dev->wait);
362	}
363
364	if (!ps2dev->cmdcnt) {
365		ps2dev->flags &= ~PS2_FLAG_CMD;
366		wake_up(&ps2dev->wait);
367	}
368
369	return 1;
370}
371EXPORT_SYMBOL(ps2_handle_response);
372
373void ps2_cmd_aborted(struct ps2dev *ps2dev)
374{
375	if (ps2dev->flags & PS2_FLAG_ACK)
376		ps2dev->nak = 1;
377
378	if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
379		wake_up(&ps2dev->wait);
380
381	ps2dev->flags = 0;
382}
383EXPORT_SYMBOL(ps2_cmd_aborted);
384