[mirror_ubuntu-hirsute-kernel.git] / drivers / input / serio / libps2.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * PS/2 driver library
 *
 * Copyright (c) 1999-2002 Vojtech Pavlik
 * Copyright (c) 2004 Dmitry Torokhov
 */


#include <linux/delay.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/i8042.h>
#include <linux/libps2.h>

#define DRIVER_DESC	"PS/2 driver library"

MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
MODULE_DESCRIPTION("PS/2 driver library");
MODULE_LICENSE("GPL");

static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte,
			   unsigned int timeout, unsigned int max_attempts)
	__releases(&ps2dev->serio->lock) __acquires(&ps2dev->serio->lock)
{
	int attempt = 0;
	int error;

	lockdep_assert_held(&ps2dev->serio->lock);

	do {
		ps2dev->nak = 1;
		ps2dev->flags |= PS2_FLAG_ACK;

		serio_continue_rx(ps2dev->serio);

		error = serio_write(ps2dev->serio, byte);
		if (error)
			dev_dbg(&ps2dev->serio->dev,
				"failed to write %#02x: %d\n", byte, error);
		else
			wait_event_timeout(ps2dev->wait,
					   !(ps2dev->flags & PS2_FLAG_ACK),
					   msecs_to_jiffies(timeout));

		serio_pause_rx(ps2dev->serio);
	} while (ps2dev->nak == PS2_RET_NAK && ++attempt < max_attempts);

	ps2dev->flags &= ~PS2_FLAG_ACK;

	if (!error) {
		switch (ps2dev->nak) {
		case 0:
			break;
		case PS2_RET_NAK:
			error = -EAGAIN;
			break;
		case PS2_RET_ERR:
			error = -EPROTO;
			break;
		default:
			error = -EIO;
			break;
		}
	}

	if (error || attempt > 1)
		dev_dbg(&ps2dev->serio->dev,
			"%02x - %d (%x), attempt %d\n",
			byte, error, ps2dev->nak, attempt);

	return error;
}

/*
 * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
 * It doesn't handle retransmission, the caller is expected to handle
 * it when needed.
 *
 * ps2_sendbyte() can only be called from a process context.
 */

int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
{
	int retval;

	serio_pause_rx(ps2dev->serio);

	retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1);
	dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);

	serio_continue_rx(ps2dev->serio);

	return retval;
}
EXPORT_SYMBOL(ps2_sendbyte);

void ps2_begin_command(struct ps2dev *ps2dev)
{
	struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;

	mutex_lock(m);
}
EXPORT_SYMBOL(ps2_begin_command);

void ps2_end_command(struct ps2dev *ps2dev)
{
	struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;

	mutex_unlock(m);
}
EXPORT_SYMBOL(ps2_end_command);

/*
 * ps2_drain() waits for device to transmit requested number of bytes
 * and discards them.
 */

void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout)
{
	if (maxbytes > sizeof(ps2dev->cmdbuf)) {
		WARN_ON(1);
		maxbytes = sizeof(ps2dev->cmdbuf);
	}

	ps2_begin_command(ps2dev);

	serio_pause_rx(ps2dev->serio);
	ps2dev->flags = PS2_FLAG_CMD;
	ps2dev->cmdcnt = maxbytes;
	serio_continue_rx(ps2dev->serio);

	wait_event_timeout(ps2dev->wait,
			   !(ps2dev->flags & PS2_FLAG_CMD),
			   msecs_to_jiffies(timeout));

	ps2_end_command(ps2dev);
}
EXPORT_SYMBOL(ps2_drain);

/*
 * ps2_is_keyboard_id() checks received ID byte against the list of
 * known keyboard IDs.
 */

bool ps2_is_keyboard_id(u8 id_byte)
{
	static const u8 keyboard_ids[] = {
		0xab,	/* Regular keyboards		*/
		0xac,	/* NCD Sun keyboard		*/
		0x2b,	/* Trust keyboard, translated	*/
		0x5d,	/* Trust keyboard		*/
		0x60,	/* NMB SGI keyboard, translated */
		0x47,	/* NMB SGI keyboard		*/
	};

	return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
}
EXPORT_SYMBOL(ps2_is_keyboard_id);

/*
 * ps2_adjust_timeout() is called after receiving 1st byte of command
 * response and tries to reduce remaining timeout to speed up command
 * completion.
 */

static int ps2_adjust_timeout(struct ps2dev *ps2dev,
			      unsigned int command, unsigned int timeout)
{
	switch (command) {
	case PS2_CMD_RESET_BAT:
		/*
		 * Device has sent the first response byte after
		 * reset command, reset is thus done, so we can
		 * shorten the timeout.
		 * The next byte will come soon (keyboard) or not
		 * at all (mouse).
		 */
		if (timeout > msecs_to_jiffies(100))
			timeout = msecs_to_jiffies(100);
		break;

	case PS2_CMD_GETID:
		/*
		 * Microsoft Natural Elite keyboard responds to
		 * the GET ID command as it were a mouse, with
		 * a single byte. Fail the command so atkbd will
		 * use alternative probe to detect it.
		 */
		if (ps2dev->cmdbuf[1] == 0xaa) {
			serio_pause_rx(ps2dev->serio);
			ps2dev->flags = 0;
			serio_continue_rx(ps2dev->serio);
			timeout = 0;
		}

		/*
		 * If device behind the port is not a keyboard there
		 * won't be 2nd byte of ID response.
		 */
		if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
			serio_pause_rx(ps2dev->serio);
			ps2dev->flags = ps2dev->cmdcnt = 0;
			serio_continue_rx(ps2dev->serio);
			timeout = 0;
		}
		break;

	default:
		break;
	}

	return timeout;
}

/*
 * ps2_command() sends a command and its parameters to the mouse,
 * then waits for the response and puts it in the param array.
 *
 * ps2_command() can only be called from a process context
 */

int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
{
	unsigned int timeout;
	unsigned int send = (command >> 12) & 0xf;
	unsigned int receive = (command >> 8) & 0xf;
	int rc;
	int i;
	u8 send_param[16];

	if (receive > sizeof(ps2dev->cmdbuf)) {
		WARN_ON(1);
		return -EINVAL;
	}

	if (send && !param) {
		WARN_ON(1);
		return -EINVAL;
	}

	memcpy(send_param, param, send);

	serio_pause_rx(ps2dev->serio);

	ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
	ps2dev->cmdcnt = receive;
	if (receive && param)
		for (i = 0; i < receive; i++)
			ps2dev->cmdbuf[(receive - 1) - i] = param[i];

	/* Signal that we are sending the command byte */
	ps2dev->flags |= PS2_FLAG_ACK_CMD;

	/*
	 * Some devices (Synaptics) peform the reset before
	 * ACKing the reset command, and so it can take a long
	 * time before the ACK arrives.
	 */
	timeout = command == PS2_CMD_RESET_BAT ? 1000 : 200;

	rc = ps2_do_sendbyte(ps2dev, command & 0xff, timeout, 2);
	if (rc)
		goto out_reset_flags;

	/* Now we are sending command parameters, if any */
	ps2dev->flags &= ~PS2_FLAG_ACK_CMD;

	for (i = 0; i < send; i++) {
		rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2);
		if (rc)
			goto out_reset_flags;
	}

	serio_continue_rx(ps2dev->serio);

	/*
	 * The reset command takes a long time to execute.
	 */
	timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);

	timeout = wait_event_timeout(ps2dev->wait,
				     !(ps2dev->flags & PS2_FLAG_CMD1), timeout);

	if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {

		timeout = ps2_adjust_timeout(ps2dev, command, timeout);
		wait_event_timeout(ps2dev->wait,
				   !(ps2dev->flags & PS2_FLAG_CMD), timeout);
	}

	serio_pause_rx(ps2dev->serio);

	if (param)
		for (i = 0; i < receive; i++)
			param[i] = ps2dev->cmdbuf[(receive - 1) - i];

	if (ps2dev->cmdcnt &&
	    (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1)) {
		rc = -EPROTO;
		goto out_reset_flags;
	}

	rc = 0;

 out_reset_flags:
	ps2dev->flags = 0;
	serio_continue_rx(ps2dev->serio);

	dev_dbg(&ps2dev->serio->dev,
		"%02x [%*ph] - %x/%08lx [%*ph]\n",
		command & 0xff, send, send_param,
		ps2dev->nak, ps2dev->flags,
		receive, param ?: send_param);

	/*
	 * ps_command() handles resends itself, so do not leak -EAGAIN
	 * to the callers.
	 */
	return rc != -EAGAIN ? rc : -EPROTO;
}
EXPORT_SYMBOL(__ps2_command);

int ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
{
	int rc;

	ps2_begin_command(ps2dev);
	rc = __ps2_command(ps2dev, param, command);
	ps2_end_command(ps2dev);

	return rc;
}
EXPORT_SYMBOL(ps2_command);

/*
 * ps2_sliced_command() sends an extended PS/2 command to the mouse
 * using sliced syntax, understood by advanced devices, such as Logitech
 * or Synaptics touchpads. The command is encoded as:
 * 0xE6 0xE8 rr 0xE8 ss 0xE8 tt 0xE8 uu where (rr*64)+(ss*16)+(tt*4)+uu
 * is the command.
 */

int ps2_sliced_command(struct ps2dev *ps2dev, u8 command)
{
	int i;
	int retval;

	ps2_begin_command(ps2dev);

	retval = __ps2_command(ps2dev, NULL, PS2_CMD_SETSCALE11);
	if (retval)
		goto out;

	for (i = 6; i >= 0; i -= 2) {
		u8 d = (command >> i) & 3;
		retval = __ps2_command(ps2dev, &d, PS2_CMD_SETRES);
		if (retval)
			break;
	}

out:
	dev_dbg(&ps2dev->serio->dev, "%02x - %d\n", command, retval);
	ps2_end_command(ps2dev);
	return retval;
}
EXPORT_SYMBOL(ps2_sliced_command);

/*
 * ps2_init() initializes ps2dev structure
 */

void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
{
	mutex_init(&ps2dev->cmd_mutex);
	lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
	init_waitqueue_head(&ps2dev->wait);
	ps2dev->serio = serio;
}
EXPORT_SYMBOL(ps2_init);

/*
 * ps2_handle_ack() is supposed to be used in interrupt handler
 * to properly process ACK/NAK of a command from a PS/2 device.
 */

bool ps2_handle_ack(struct ps2dev *ps2dev, u8 data)
{
	switch (data) {
	case PS2_RET_ACK:
		ps2dev->nak = 0;
		break;

	case PS2_RET_NAK:
		ps2dev->flags |= PS2_FLAG_NAK;
		ps2dev->nak = PS2_RET_NAK;
		break;

	case PS2_RET_ERR:
		if (ps2dev->flags & PS2_FLAG_NAK) {
			ps2dev->flags &= ~PS2_FLAG_NAK;
			ps2dev->nak = PS2_RET_ERR;
			break;
		}
		/* Fall through */

	/*
	 * Workaround for mice which don't ACK the Get ID command.
	 * These are valid mouse IDs that we recognize.
	 */
	case 0x00:
	case 0x03:
	case 0x04:
		if (ps2dev->flags & PS2_FLAG_WAITID) {
			ps2dev->nak = 0;
			break;
		}
		/* Fall through */
	default:
		/*
		 * Do not signal errors if we get unexpected reply while
		 * waiting for an ACK to the initial (first) command byte:
		 * the device might not be quiesced yet and continue
		 * delivering data.
		 * Note that we reset PS2_FLAG_WAITID flag, so the workaround
		 * for mice not acknowledging the Get ID command only triggers
		 * on the 1st byte; if device spews data we really want to see
		 * a real ACK from it.
		 */
		dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data);
		ps2dev->flags &= ~PS2_FLAG_WAITID;
		return ps2dev->flags & PS2_FLAG_ACK_CMD;
	}

	if (!ps2dev->nak) {
		ps2dev->flags &= ~PS2_FLAG_NAK;
		if (ps2dev->cmdcnt)
			ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
	}

	ps2dev->flags &= ~PS2_FLAG_ACK;
	wake_up(&ps2dev->wait);

	if (data != PS2_RET_ACK)
		ps2_handle_response(ps2dev, data);

	return true;
}
EXPORT_SYMBOL(ps2_handle_ack);

/*
 * ps2_handle_response() is supposed to be used in interrupt handler
 * to properly store device's response to a command and notify process
 * waiting for completion of the command.
 */

bool ps2_handle_response(struct ps2dev *ps2dev, u8 data)
{
	if (ps2dev->cmdcnt)
		ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;

	if (ps2dev->flags & PS2_FLAG_CMD1) {
		ps2dev->flags &= ~PS2_FLAG_CMD1;
		if (ps2dev->cmdcnt)
			wake_up(&ps2dev->wait);
	}

	if (!ps2dev->cmdcnt) {
		ps2dev->flags &= ~PS2_FLAG_CMD;
		wake_up(&ps2dev->wait);
	}

	return true;
}
EXPORT_SYMBOL(ps2_handle_response);

void ps2_cmd_aborted(struct ps2dev *ps2dev)
{
	if (ps2dev->flags & PS2_FLAG_ACK)
		ps2dev->nak = 1;

	if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
		wake_up(&ps2dev->wait);

	/* reset all flags except last nack */
	ps2dev->flags &= PS2_FLAG_NAK;
}
EXPORT_SYMBOL(ps2_cmd_aborted);
Commit	Line	Data
	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/serio.h>
	16	#include <linux/i8042.h>
	17	#include <linux/libps2.h>
	18
	19	#define DRIVER_DESC "PS/2 driver library"
	20
	21	MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
	22	MODULE_DESCRIPTION("PS/2 driver library");
	23	MODULE_LICENSE("GPL");
	24
	25	static int ps2_do_sendbyte(struct ps2dev *ps2dev, u8 byte,
	26	unsigned int timeout, unsigned int max_attempts)
	27	__releases(&ps2dev->serio->lock) __acquires(&ps2dev->serio->lock)
	28	{
	29	int attempt = 0;
	30	int error;
	31
	32	lockdep_assert_held(&ps2dev->serio->lock);
	33
	34	do {
	35	ps2dev->nak = 1;
	36	ps2dev->flags \|= PS2_FLAG_ACK;
	37
	38	serio_continue_rx(ps2dev->serio);
	39
	40	error = serio_write(ps2dev->serio, byte);
	41	if (error)
	42	dev_dbg(&ps2dev->serio->dev,
	43	"failed to write %#02x: %d\n", byte, error);
	44	else
	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	} while (ps2dev->nak == PS2_RET_NAK && ++attempt < max_attempts);
	51
	52	ps2dev->flags &= ~PS2_FLAG_ACK;
	53
	54	if (!error) {
	55	switch (ps2dev->nak) {
	56	case 0:
	57	break;
	58	case PS2_RET_NAK:
	59	error = -EAGAIN;
	60	break;
	61	case PS2_RET_ERR:
	62	error = -EPROTO;
	63	break;
	64	default:
	65	error = -EIO;
	66	break;
	67	}
	68	}
	69
	70	if (error \|\| attempt > 1)
	71	dev_dbg(&ps2dev->serio->dev,
	72	"%02x - %d (%x), attempt %d\n",
	73	byte, error, ps2dev->nak, attempt);
	74
	75	return error;
	76	}
	77
	78	/*
	79	* ps2_sendbyte() sends a byte to the device and waits for acknowledge.
	80	* It doesn't handle retransmission, the caller is expected to handle
	81	* it when needed.
	82	*
	83	* ps2_sendbyte() can only be called from a process context.
	84	*/
	85
	86	int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
	87	{
	88	int retval;
	89
	90	serio_pause_rx(ps2dev->serio);
	91
	92	retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1);
	93	dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);
	94
	95	serio_continue_rx(ps2dev->serio);
	96
	97	return retval;
	98	}
	99	EXPORT_SYMBOL(ps2_sendbyte);
	100
	101	void ps2_begin_command(struct ps2dev *ps2dev)
	102	{
	103	struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
	104
	105	mutex_lock(m);
	106	}
	107	EXPORT_SYMBOL(ps2_begin_command);
	108
	109	void ps2_end_command(struct ps2dev *ps2dev)
	110	{
	111	struct mutex *m = ps2dev->serio->ps2_cmd_mutex ?: &ps2dev->cmd_mutex;
	112
	113	mutex_unlock(m);
	114	}
	115	EXPORT_SYMBOL(ps2_end_command);
	116
	117	/*
	118	* ps2_drain() waits for device to transmit requested number of bytes
	119	* and discards them.
	120	*/
	121
	122	void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout)
	123	{
	124	if (maxbytes > sizeof(ps2dev->cmdbuf)) {
	125	WARN_ON(1);
	126	maxbytes = sizeof(ps2dev->cmdbuf);
	127	}
	128
	129	ps2_begin_command(ps2dev);
	130
	131	serio_pause_rx(ps2dev->serio);
	132	ps2dev->flags = PS2_FLAG_CMD;
	133	ps2dev->cmdcnt = maxbytes;
	134	serio_continue_rx(ps2dev->serio);
	135
	136	wait_event_timeout(ps2dev->wait,
	137	!(ps2dev->flags & PS2_FLAG_CMD),
	138	msecs_to_jiffies(timeout));
	139
	140	ps2_end_command(ps2dev);
	141	}
	142	EXPORT_SYMBOL(ps2_drain);
	143
	144	/*
	145	* ps2_is_keyboard_id() checks received ID byte against the list of
	146	* known keyboard IDs.
	147	*/
	148
	149	bool ps2_is_keyboard_id(u8 id_byte)
	150	{
	151	static const u8 keyboard_ids[] = {
	152	0xab, /* Regular keyboards */
	153	0xac, /* NCD Sun keyboard */
	154	0x2b, /* Trust keyboard, translated */
	155	0x5d, /* Trust keyboard */
	156	0x60, /* NMB SGI keyboard, translated */
	157	0x47, /* NMB SGI keyboard */
	158	};
	159
	160	return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
	161	}
	162	EXPORT_SYMBOL(ps2_is_keyboard_id);
	163
	164	/*
	165	* ps2_adjust_timeout() is called after receiving 1st byte of command
	166	* response and tries to reduce remaining timeout to speed up command
	167	* completion.
	168	*/
	169
	170	static int ps2_adjust_timeout(struct ps2dev *ps2dev,
	171	unsigned int command, unsigned int timeout)
	172	{
	173	switch (command) {
	174	case PS2_CMD_RESET_BAT:
	175	/*
	176	* Device has sent the first response byte after
	177	* reset command, reset is thus done, so we can
	178	* shorten the timeout.
	179	* The next byte will come soon (keyboard) or not
	180	* at all (mouse).
	181	*/
	182	if (timeout > msecs_to_jiffies(100))
	183	timeout = msecs_to_jiffies(100);
	184	break;
	185
	186	case PS2_CMD_GETID:
	187	/*
	188	* Microsoft Natural Elite keyboard responds to
	189	* the GET ID command as it were a mouse, with
	190	* a single byte. Fail the command so atkbd will
	191	* use alternative probe to detect it.
	192	*/
	193	if (ps2dev->cmdbuf[1] == 0xaa) {
	194	serio_pause_rx(ps2dev->serio);
	195	ps2dev->flags = 0;
	196	serio_continue_rx(ps2dev->serio);
	197	timeout = 0;
	198	}
	199
	200	/*
	201	* If device behind the port is not a keyboard there
	202	* won't be 2nd byte of ID response.
	203	*/
	204	if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
	205	serio_pause_rx(ps2dev->serio);
	206	ps2dev->flags = ps2dev->cmdcnt = 0;
	207	serio_continue_rx(ps2dev->serio);
	208	timeout = 0;
	209	}
	210	break;
	211
	212	default:
	213	break;
	214	}
	215
	216	return timeout;
	217	}
	218
	219	/*
	220	* ps2_command() sends a command and its parameters to the mouse,
	221	* then waits for the response and puts it in the param array.
	222	*
	223	* ps2_command() can only be called from a process context
	224	*/
	225
	226	int __ps2_command(struct ps2dev ps2dev, u8 param, unsigned int command)
	227	{
	228	unsigned int timeout;
	229	unsigned int send = (command >> 12) & 0xf;
	230	unsigned int receive = (command >> 8) & 0xf;
	231	int rc;
	232	int i;
	233	u8 send_param[16];
	234
	235	if (receive > sizeof(ps2dev->cmdbuf)) {
	236	WARN_ON(1);
	237	return -EINVAL;
	238	}
	239
	240	if (send && !param) {
	241	WARN_ON(1);
	242	return -EINVAL;
	243	}
	244
	245	memcpy(send_param, param, send);
	246
	247	serio_pause_rx(ps2dev->serio);
	248
	249	ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
	250	ps2dev->cmdcnt = receive;
	251	if (receive && param)
	252	for (i = 0; i < receive; i++)
	253	ps2dev->cmdbuf[(receive - 1) - i] = param[i];
	254
	255	/* Signal that we are sending the command byte */
	256	ps2dev->flags \|= PS2_FLAG_ACK_CMD;
	257
	258	/*
	259	* Some devices (Synaptics) peform the reset before
	260	* ACKing the reset command, and so it can take a long
	261	* time before the ACK arrives.
	262	*/
	263	timeout = command == PS2_CMD_RESET_BAT ? 1000 : 200;
	264
	265	rc = ps2_do_sendbyte(ps2dev, command & 0xff, timeout, 2);
	266	if (rc)
	267	goto out_reset_flags;
	268
	269	/* Now we are sending command parameters, if any */
	270	ps2dev->flags &= ~PS2_FLAG_ACK_CMD;
	271
	272	for (i = 0; i < send; i++) {
	273	rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2);
	274	if (rc)
	275	goto out_reset_flags;
	276	}
	277
	278	serio_continue_rx(ps2dev->serio);
	279
	280	/*
	281	* The reset command takes a long time to execute.
	282	*/
	283	timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
	284
	285	timeout = wait_event_timeout(ps2dev->wait,
	286	!(ps2dev->flags & PS2_FLAG_CMD1), timeout);
	287
	288	if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
	289
	290	timeout = ps2_adjust_timeout(ps2dev, command, timeout);
	291	wait_event_timeout(ps2dev->wait,
	292	!(ps2dev->flags & PS2_FLAG_CMD), timeout);
	293	}
	294
	295	serio_pause_rx(ps2dev->serio);
	296
	297	if (param)
	298	for (i = 0; i < receive; i++)
	299	param[i] = ps2dev->cmdbuf[(receive - 1) - i];
	300
	301	if (ps2dev->cmdcnt &&
	302	(command != PS2_CMD_RESET_BAT \|\| ps2dev->cmdcnt != 1)) {
	303	rc = -EPROTO;
	304	goto out_reset_flags;
	305	}
	306
	307	rc = 0;
	308
	309	out_reset_flags:
	310	ps2dev->flags = 0;
	311	serio_continue_rx(ps2dev->serio);
	312
	313	dev_dbg(&ps2dev->serio->dev,
	314	"%02x [%ph] - %x/%08lx [%ph]\n",
	315	command & 0xff, send, send_param,
	316	ps2dev->nak, ps2dev->flags,
	317	receive, param ?: send_param);
	318
	319	/*
	320	* ps_command() handles resends itself, so do not leak -EAGAIN
	321	* to the callers.
	322	*/
	323	return rc != -EAGAIN ? rc : -EPROTO;
	324	}
	325	EXPORT_SYMBOL(__ps2_command);
	326
	327	int ps2_command(struct ps2dev ps2dev, u8 param, unsigned int command)
	328	{
	329	int rc;
	330
	331	ps2_begin_command(ps2dev);
	332	rc = __ps2_command(ps2dev, param, command);
	333	ps2_end_command(ps2dev);
	334
	335	return rc;
	336	}
	337	EXPORT_SYMBOL(ps2_command);
	338
	339	/*
	340	* ps2_sliced_command() sends an extended PS/2 command to the mouse
	341	* using sliced syntax, understood by advanced devices, such as Logitech
	342	* or Synaptics touchpads. The command is encoded as:
	343	* 0xE6 0xE8 rr 0xE8 ss 0xE8 tt 0xE8 uu where (rr64)+(ss16)+(tt*4)+uu
	344	* is the command.
	345	*/
	346
	347	int ps2_sliced_command(struct ps2dev *ps2dev, u8 command)
	348	{
	349	int i;
	350	int retval;
	351
	352	ps2_begin_command(ps2dev);
	353
	354	retval = __ps2_command(ps2dev, NULL, PS2_CMD_SETSCALE11);
	355	if (retval)
	356	goto out;
	357
	358	for (i = 6; i >= 0; i -= 2) {
	359	u8 d = (command >> i) & 3;
	360	retval = __ps2_command(ps2dev, &d, PS2_CMD_SETRES);
	361	if (retval)
	362	break;
	363	}
	364
	365	out:
	366	dev_dbg(&ps2dev->serio->dev, "%02x - %d\n", command, retval);
	367	ps2_end_command(ps2dev);
	368	return retval;
	369	}
	370	EXPORT_SYMBOL(ps2_sliced_command);
	371
	372	/*
	373	* ps2_init() initializes ps2dev structure
	374	*/
	375
	376	void ps2_init(struct ps2dev ps2dev, struct serio serio)
	377	{
	378	mutex_init(&ps2dev->cmd_mutex);
	379	lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
	380	init_waitqueue_head(&ps2dev->wait);
	381	ps2dev->serio = serio;
	382	}
	383	EXPORT_SYMBOL(ps2_init);
	384
	385	/*
	386	* ps2_handle_ack() is supposed to be used in interrupt handler
	387	* to properly process ACK/NAK of a command from a PS/2 device.
	388	*/
	389
	390	bool ps2_handle_ack(struct ps2dev *ps2dev, u8 data)
	391	{
	392	switch (data) {
	393	case PS2_RET_ACK:
	394	ps2dev->nak = 0;
	395	break;
	396
	397	case PS2_RET_NAK:
	398	ps2dev->flags \|= PS2_FLAG_NAK;
	399	ps2dev->nak = PS2_RET_NAK;
	400	break;
	401
	402	case PS2_RET_ERR:
	403	if (ps2dev->flags & PS2_FLAG_NAK) {
	404	ps2dev->flags &= ~PS2_FLAG_NAK;
	405	ps2dev->nak = PS2_RET_ERR;
	406	break;
	407	}
	408	/* Fall through */
	409
	410	/*
	411	* Workaround for mice which don't ACK the Get ID command.
	412	* These are valid mouse IDs that we recognize.
	413	*/
	414	case 0x00:
	415	case 0x03:
	416	case 0x04:
	417	if (ps2dev->flags & PS2_FLAG_WAITID) {
	418	ps2dev->nak = 0;
	419	break;
	420	}
	421	/* Fall through */
	422	default:
	423	/*
	424	* Do not signal errors if we get unexpected reply while
	425	* waiting for an ACK to the initial (first) command byte:
	426	* the device might not be quiesced yet and continue
	427	* delivering data.
	428	* Note that we reset PS2_FLAG_WAITID flag, so the workaround
	429	* for mice not acknowledging the Get ID command only triggers
	430	* on the 1st byte; if device spews data we really want to see
	431	* a real ACK from it.
	432	*/
	433	dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data);
	434	ps2dev->flags &= ~PS2_FLAG_WAITID;
	435	return ps2dev->flags & PS2_FLAG_ACK_CMD;
	436	}
	437
	438	if (!ps2dev->nak) {
	439	ps2dev->flags &= ~PS2_FLAG_NAK;
	440	if (ps2dev->cmdcnt)
	441	ps2dev->flags \|= PS2_FLAG_CMD \| PS2_FLAG_CMD1;
	442	}
	443
	444	ps2dev->flags &= ~PS2_FLAG_ACK;
	445	wake_up(&ps2dev->wait);
	446
	447	if (data != PS2_RET_ACK)
	448	ps2_handle_response(ps2dev, data);
	449
	450	return true;
	451	}
	452	EXPORT_SYMBOL(ps2_handle_ack);
	453
	454	/*
	455	* ps2_handle_response() is supposed to be used in interrupt handler
	456	* to properly store device's response to a command and notify process
	457	* waiting for completion of the command.
	458	*/
	459
	460	bool ps2_handle_response(struct ps2dev *ps2dev, u8 data)
	461	{
	462	if (ps2dev->cmdcnt)
	463	ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
	464
	465	if (ps2dev->flags & PS2_FLAG_CMD1) {
	466	ps2dev->flags &= ~PS2_FLAG_CMD1;
	467	if (ps2dev->cmdcnt)
	468	wake_up(&ps2dev->wait);
	469	}
	470
	471	if (!ps2dev->cmdcnt) {
	472	ps2dev->flags &= ~PS2_FLAG_CMD;
	473	wake_up(&ps2dev->wait);
	474	}
	475
	476	return true;
	477	}
	478	EXPORT_SYMBOL(ps2_handle_response);
	479
	480	void ps2_cmd_aborted(struct ps2dev *ps2dev)
	481	{
	482	if (ps2dev->flags & PS2_FLAG_ACK)
	483	ps2dev->nak = 1;
	484
	485	if (ps2dev->flags & (PS2_FLAG_ACK \| PS2_FLAG_CMD))
	486	wake_up(&ps2dev->wait);
	487
	488	/* reset all flags except last nack */
	489	ps2dev->flags &= PS2_FLAG_NAK;
	490	}
	491	EXPORT_SYMBOL(ps2_cmd_aborted);