drivers/input/serio/libps2.c - kernel/bruno - Git at Google

 /*
  * PS/2 driver library
  *
  * Copyright (c) 1999-2002 Vojtech Pavlik
  * Copyright (c) 2004 Dmitry Torokhov
  */

 /*
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  */

 #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");

 /*
  * ps2_sendbyte() sends a byte to the device and waits for acknowledge.
  * It doesn't handle retransmission, though it could - because if there
  * is a need for retransmissions device has to be replaced anyway.
  *
  * ps2_sendbyte() can only be called from a process context.
  */

 int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
 {
 	serio_pause_rx(ps2dev->serio);
 	ps2dev->nak = 1;
 	ps2dev->flags |= PS2_FLAG_ACK;
 	serio_continue_rx(ps2dev->serio);

 	if (serio_write(ps2dev->serio, byte) == 0)
 		wait_event_timeout(ps2dev->wait,
 				   !(ps2dev->flags & PS2_FLAG_ACK),
 				   msecs_to_jiffies(timeout));

 	serio_pause_rx(ps2dev->serio);
 	ps2dev->flags &= ~PS2_FLAG_ACK;
 	serio_continue_rx(ps2dev->serio);

 	return -ps2dev->nak;
 }
 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, int maxbytes, 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.
  */

 int ps2_is_keyboard_id(char id_byte)
 {
 	static const char 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, int command, 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, unsigned char *param, int command)
 {
 	int timeout;
 	int send = (command >> 12) & 0xf;
 	int receive = (command >> 8) & 0xf;
 	int rc = -1;
 	int i;

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

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

 	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];
 	serio_continue_rx(ps2dev->serio);

 	/*
 	 * Some devices (Synaptics) peform the reset before
 	 * ACKing the reset command, and so it can take a long
 	 * time before the ACK arrives.
 	 */
 	if (ps2_sendbyte(ps2dev, command & 0xff,
 			 command == PS2_CMD_RESET_BAT ? 1000 : 200)) {
 		serio_pause_rx(ps2dev->serio);
 		goto out_reset_flags;
 	}

 	for (i = 0; i < send; i++) {
 		if (ps2_sendbyte(ps2dev, param[i], 200)) {
 			serio_pause_rx(ps2dev->serio);
 			goto out_reset_flags;
 		}
 	}

 	/*
 	 * 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))
 		goto out_reset_flags;

 	rc = 0;

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

 	return rc;
 }
 EXPORT_SYMBOL(__ps2_command);

 int ps2_command(struct ps2dev *ps2dev, unsigned char *param, 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_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.
  */

 int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char 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;
 			}

 		/*
 		 * 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:
 			return 0;
 	}


 	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 1;
 }
 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.
  */

 int ps2_handle_response(struct ps2dev *ps2dev, unsigned char 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 1;
 }
 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);
	/*
	* PS/2 driver library
	*
	* Copyright (c) 1999-2002 Vojtech Pavlik
	* Copyright (c) 2004 Dmitry Torokhov
	*/

	/*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published by
	* the Free Software Foundation.
	*/

	#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");

	/*
	* ps2_sendbyte() sends a byte to the device and waits for acknowledge.
	* It doesn't handle retransmission, though it could - because if there
	* is a need for retransmissions device has to be replaced anyway.
	*
	* ps2_sendbyte() can only be called from a process context.
	*/

	int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
	{
	serio_pause_rx(ps2dev->serio);
	ps2dev->nak = 1;
	ps2dev->flags \|= PS2_FLAG_ACK;
	serio_continue_rx(ps2dev->serio);

	if (serio_write(ps2dev->serio, byte) == 0)
	wait_event_timeout(ps2dev->wait,
	!(ps2dev->flags & PS2_FLAG_ACK),
	msecs_to_jiffies(timeout));

	serio_pause_rx(ps2dev->serio);
	ps2dev->flags &= ~PS2_FLAG_ACK;
	serio_continue_rx(ps2dev->serio);

	return -ps2dev->nak;
	}
	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, int maxbytes, 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.
	*/

	int ps2_is_keyboard_id(char id_byte)
	{
	static const char 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, int command, 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, unsigned char param, int command)
	{
	int timeout;
	int send = (command >> 12) & 0xf;
	int receive = (command >> 8) & 0xf;
	int rc = -1;
	int i;

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

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

	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];
	serio_continue_rx(ps2dev->serio);

	/*
	* Some devices (Synaptics) peform the reset before
	* ACKing the reset command, and so it can take a long
	* time before the ACK arrives.
	*/
	if (ps2_sendbyte(ps2dev, command & 0xff,
	command == PS2_CMD_RESET_BAT ? 1000 : 200)) {
	serio_pause_rx(ps2dev->serio);
	goto out_reset_flags;
	}

	for (i = 0; i < send; i++) {
	if (ps2_sendbyte(ps2dev, param[i], 200)) {
	serio_pause_rx(ps2dev->serio);
	goto out_reset_flags;
	}
	}

	/*
	* 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))
	goto out_reset_flags;

	rc = 0;

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

	return rc;
	}
	EXPORT_SYMBOL(__ps2_command);

	int ps2_command(struct ps2dev ps2dev, unsigned char param, 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_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.
	*/

	int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char 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;
	}

	/*
	* 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:
	return 0;
	}


	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 1;
	}
	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.
	*/

	int ps2_handle_response(struct ps2dev *ps2dev, unsigned char 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 1;
	}
	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);