/*
* 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/moduleparam.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/init.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");
EXPORT_SYMBOL(ps2_init);
EXPORT_SYMBOL(ps2_sendbyte);
EXPORT_SYMBOL(ps2_drain);
EXPORT_SYMBOL(ps2_command);
EXPORT_SYMBOL(ps2_schedule_command);
EXPORT_SYMBOL(ps2_handle_ack);
EXPORT_SYMBOL(ps2_handle_response);
EXPORT_SYMBOL(ps2_cmd_aborted);
/* Work structure to schedule execution of a command */
struct ps2work {
struct work_struct work;
struct ps2dev *ps2dev;
int command;
unsigned char param[0];
};
/*
* 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;
}
/*
* 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);
}
mutex_lock(&ps2dev->cmd_mutex);
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));
mutex_unlock(&ps2dev->cmd_mutex);
}
/*
* ps2_is_keyboard_id() checks received ID byte against the list of
* known keyboard IDs.
*/
static inline int ps2_is_keyboard_id(char id_byte)
{
static 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;
}
/*
* 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:
/*
* 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;
}
mutex_lock_nested(&ps2dev->cmd_mutex, SINGLE_DEPTH_NESTING);
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 arrrives.
*/
if (ps2_sendbyte(ps2dev, command & 0xff,
command == PS2_CMD_RESET_BAT ? 1000 : 200))
goto out;
for (i = 0; i < send; i++)
if (ps2_sendbyte(ps2dev, param[i], 200))
goto out;
/*
* 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 && timeout > 0) {
timeout = ps2_adjust_timeout(ps2dev, command, timeout);
wait_event_timeout(ps2dev->wait,
!(ps2dev->flags & PS2_FLAG_CMD), timeout);
}
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;
rc = 0;
out:
serio_pause_rx(ps2dev->serio);
ps2dev->flags = 0;
serio_continue_rx(ps2dev->serio);
mutex_unlock(&ps2dev->cmd_mutex);
return rc;
}
/*
* ps2_execute_scheduled_command() sends a command, previously scheduled by
* ps2_schedule_command(), to a PS/2 device (keyboard, mouse, etc.)
*/
static void ps2_execute_scheduled_command(void *data)
{
struct ps2work *ps2work = data;
ps2_command(ps2work->ps2dev, ps2work->param, ps2work->command);
kfree(ps2work);
}
/*
* ps2_schedule_command() allows to schedule delayed execution of a PS/2
* command and can be used to issue a command from an interrupt or softirq
* context.
*/
int ps2_schedule_command(struct ps2dev *ps2dev, unsigned char *param, int command)
{
struct ps2work *ps2work;
int send = (command >> 12) & 0xf;
int receive = (command >> 8) & 0xf;
if (!(ps2work = kmalloc(sizeof(struct ps2work) + max(send, receive), GFP_ATOMIC)))
return -1;
memset(ps2work, 0, sizeof(struct ps2work));
ps2work->ps2dev = ps2dev;
ps2work->command = command;
memcpy(ps2work->param, param, send);
INIT_WORK(&ps2work->work, ps2_execute_scheduled_command, ps2work);
if (!schedule_work(&ps2work->work)) {
kfree(ps2work);
return -1;
}
return 0;
}
/*
* ps2_init() initializes ps2dev structure
*/
void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
{
mutex_init(&ps2dev->cmd_mutex);
init_waitqueue_head(&ps2dev->wait);
ps2dev->serio = serio;
}
/*
* 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->nak = 1;
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->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;
}
/*
* 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;
}
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);
ps2dev->flags = 0;
}
