387 lines
8.9 KiB
C
387 lines
8.9 KiB
C
/*
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* PS/2 driver library
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*
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* Copyright (c) 1999-2002 Vojtech Pavlik
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* Copyright (c) 2004 Dmitry Torokhov
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*/
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/*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/input.h>
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#include <linux/serio.h>
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#include <linux/init.h>
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#include <linux/libps2.h>
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#define DRIVER_DESC "PS/2 driver library"
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MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
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MODULE_DESCRIPTION("PS/2 driver library");
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MODULE_LICENSE("GPL");
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/* Work structure to schedule execution of a command */
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struct ps2work {
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struct work_struct work;
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struct ps2dev *ps2dev;
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int command;
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unsigned char param[0];
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};
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/*
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* ps2_sendbyte() sends a byte to the device and waits for acknowledge.
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* It doesn't handle retransmission, though it could - because if there
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* is a need for retransmissions device has to be replaced anyway.
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*
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* ps2_sendbyte() can only be called from a process context.
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*/
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int ps2_sendbyte(struct ps2dev *ps2dev, unsigned char byte, int timeout)
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{
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serio_pause_rx(ps2dev->serio);
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ps2dev->nak = 1;
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ps2dev->flags |= PS2_FLAG_ACK;
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serio_continue_rx(ps2dev->serio);
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if (serio_write(ps2dev->serio, byte) == 0)
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wait_event_timeout(ps2dev->wait,
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!(ps2dev->flags & PS2_FLAG_ACK),
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msecs_to_jiffies(timeout));
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serio_pause_rx(ps2dev->serio);
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ps2dev->flags &= ~PS2_FLAG_ACK;
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serio_continue_rx(ps2dev->serio);
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return -ps2dev->nak;
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}
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EXPORT_SYMBOL(ps2_sendbyte);
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/*
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* ps2_drain() waits for device to transmit requested number of bytes
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* and discards them.
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*/
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void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
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{
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if (maxbytes > sizeof(ps2dev->cmdbuf)) {
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WARN_ON(1);
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maxbytes = sizeof(ps2dev->cmdbuf);
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}
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mutex_lock(&ps2dev->cmd_mutex);
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serio_pause_rx(ps2dev->serio);
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ps2dev->flags = PS2_FLAG_CMD;
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ps2dev->cmdcnt = maxbytes;
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serio_continue_rx(ps2dev->serio);
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wait_event_timeout(ps2dev->wait,
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!(ps2dev->flags & PS2_FLAG_CMD),
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msecs_to_jiffies(timeout));
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mutex_unlock(&ps2dev->cmd_mutex);
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}
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EXPORT_SYMBOL(ps2_drain);
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/*
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* ps2_is_keyboard_id() checks received ID byte against the list of
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* known keyboard IDs.
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*/
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int ps2_is_keyboard_id(char id_byte)
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{
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static const char keyboard_ids[] = {
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0xab, /* Regular keyboards */
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0xac, /* NCD Sun keyboard */
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0x2b, /* Trust keyboard, translated */
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0x5d, /* Trust keyboard */
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0x60, /* NMB SGI keyboard, translated */
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0x47, /* NMB SGI keyboard */
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};
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return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
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}
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EXPORT_SYMBOL(ps2_is_keyboard_id);
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/*
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* ps2_adjust_timeout() is called after receiving 1st byte of command
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* response and tries to reduce remaining timeout to speed up command
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* completion.
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*/
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static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
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{
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switch (command) {
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case PS2_CMD_RESET_BAT:
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/*
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* Device has sent the first response byte after
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* reset command, reset is thus done, so we can
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* shorten the timeout.
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* The next byte will come soon (keyboard) or not
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* at all (mouse).
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*/
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if (timeout > msecs_to_jiffies(100))
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timeout = msecs_to_jiffies(100);
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break;
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case PS2_CMD_GETID:
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/*
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* Microsoft Natural Elite keyboard responds to
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* the GET ID command as it were a mouse, with
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* a single byte. Fail the command so atkbd will
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* use alternative probe to detect it.
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*/
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if (ps2dev->cmdbuf[1] == 0xaa) {
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serio_pause_rx(ps2dev->serio);
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ps2dev->flags = 0;
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serio_continue_rx(ps2dev->serio);
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timeout = 0;
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}
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/*
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* If device behind the port is not a keyboard there
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* won't be 2nd byte of ID response.
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*/
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if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
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serio_pause_rx(ps2dev->serio);
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ps2dev->flags = ps2dev->cmdcnt = 0;
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serio_continue_rx(ps2dev->serio);
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timeout = 0;
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}
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break;
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default:
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break;
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}
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return timeout;
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}
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/*
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* ps2_command() sends a command and its parameters to the mouse,
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* then waits for the response and puts it in the param array.
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*
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* ps2_command() can only be called from a process context
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*/
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int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
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{
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int timeout;
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int send = (command >> 12) & 0xf;
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int receive = (command >> 8) & 0xf;
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int rc = -1;
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int i;
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if (receive > sizeof(ps2dev->cmdbuf)) {
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WARN_ON(1);
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return -1;
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}
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if (send && !param) {
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WARN_ON(1);
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return -1;
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}
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mutex_lock(&ps2dev->cmd_mutex);
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serio_pause_rx(ps2dev->serio);
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ps2dev->flags = command == PS2_CMD_GETID ? PS2_FLAG_WAITID : 0;
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ps2dev->cmdcnt = receive;
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if (receive && param)
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for (i = 0; i < receive; i++)
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ps2dev->cmdbuf[(receive - 1) - i] = param[i];
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serio_continue_rx(ps2dev->serio);
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/*
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* Some devices (Synaptics) peform the reset before
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* ACKing the reset command, and so it can take a long
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* time before the ACK arrrives.
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*/
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if (ps2_sendbyte(ps2dev, command & 0xff,
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command == PS2_CMD_RESET_BAT ? 1000 : 200))
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goto out;
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for (i = 0; i < send; i++)
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if (ps2_sendbyte(ps2dev, param[i], 200))
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goto out;
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/*
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* The reset command takes a long time to execute.
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*/
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timeout = msecs_to_jiffies(command == PS2_CMD_RESET_BAT ? 4000 : 500);
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timeout = wait_event_timeout(ps2dev->wait,
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!(ps2dev->flags & PS2_FLAG_CMD1), timeout);
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if (ps2dev->cmdcnt && timeout > 0) {
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timeout = ps2_adjust_timeout(ps2dev, command, timeout);
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wait_event_timeout(ps2dev->wait,
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!(ps2dev->flags & PS2_FLAG_CMD), timeout);
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}
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if (param)
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for (i = 0; i < receive; i++)
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param[i] = ps2dev->cmdbuf[(receive - 1) - i];
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if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
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goto out;
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rc = 0;
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out:
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serio_pause_rx(ps2dev->serio);
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ps2dev->flags = 0;
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serio_continue_rx(ps2dev->serio);
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mutex_unlock(&ps2dev->cmd_mutex);
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return rc;
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}
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EXPORT_SYMBOL(ps2_command);
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/*
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* ps2_execute_scheduled_command() sends a command, previously scheduled by
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* ps2_schedule_command(), to a PS/2 device (keyboard, mouse, etc.)
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*/
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static void ps2_execute_scheduled_command(struct work_struct *work)
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{
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struct ps2work *ps2work = container_of(work, struct ps2work, work);
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ps2_command(ps2work->ps2dev, ps2work->param, ps2work->command);
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kfree(ps2work);
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}
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/*
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* ps2_schedule_command() allows to schedule delayed execution of a PS/2
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* command and can be used to issue a command from an interrupt or softirq
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* context.
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*/
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int ps2_schedule_command(struct ps2dev *ps2dev, unsigned char *param, int command)
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{
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struct ps2work *ps2work;
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int send = (command >> 12) & 0xf;
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int receive = (command >> 8) & 0xf;
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if (!(ps2work = kmalloc(sizeof(struct ps2work) + max(send, receive), GFP_ATOMIC)))
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return -1;
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memset(ps2work, 0, sizeof(struct ps2work));
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ps2work->ps2dev = ps2dev;
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ps2work->command = command;
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memcpy(ps2work->param, param, send);
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INIT_WORK(&ps2work->work, ps2_execute_scheduled_command);
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if (!schedule_work(&ps2work->work)) {
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kfree(ps2work);
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return -1;
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}
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return 0;
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}
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EXPORT_SYMBOL(ps2_schedule_command);
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/*
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* ps2_init() initializes ps2dev structure
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*/
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void ps2_init(struct ps2dev *ps2dev, struct serio *serio)
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{
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mutex_init(&ps2dev->cmd_mutex);
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lockdep_set_subclass(&ps2dev->cmd_mutex, serio->depth);
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init_waitqueue_head(&ps2dev->wait);
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ps2dev->serio = serio;
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}
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EXPORT_SYMBOL(ps2_init);
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/*
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* ps2_handle_ack() is supposed to be used in interrupt handler
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* to properly process ACK/NAK of a command from a PS/2 device.
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*/
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int ps2_handle_ack(struct ps2dev *ps2dev, unsigned char data)
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{
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switch (data) {
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case PS2_RET_ACK:
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ps2dev->nak = 0;
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break;
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case PS2_RET_NAK:
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ps2dev->nak = 1;
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break;
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/*
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* Workaround for mice which don't ACK the Get ID command.
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* These are valid mouse IDs that we recognize.
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*/
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case 0x00:
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case 0x03:
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case 0x04:
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if (ps2dev->flags & PS2_FLAG_WAITID) {
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ps2dev->nak = 0;
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break;
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}
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/* Fall through */
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default:
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return 0;
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}
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if (!ps2dev->nak && ps2dev->cmdcnt)
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ps2dev->flags |= PS2_FLAG_CMD | PS2_FLAG_CMD1;
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ps2dev->flags &= ~PS2_FLAG_ACK;
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wake_up(&ps2dev->wait);
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if (data != PS2_RET_ACK)
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ps2_handle_response(ps2dev, data);
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return 1;
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}
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EXPORT_SYMBOL(ps2_handle_ack);
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/*
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* ps2_handle_response() is supposed to be used in interrupt handler
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* to properly store device's response to a command and notify process
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* waiting for completion of the command.
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*/
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int ps2_handle_response(struct ps2dev *ps2dev, unsigned char data)
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{
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if (ps2dev->cmdcnt)
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ps2dev->cmdbuf[--ps2dev->cmdcnt] = data;
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if (ps2dev->flags & PS2_FLAG_CMD1) {
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ps2dev->flags &= ~PS2_FLAG_CMD1;
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if (ps2dev->cmdcnt)
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wake_up(&ps2dev->wait);
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}
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if (!ps2dev->cmdcnt) {
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ps2dev->flags &= ~PS2_FLAG_CMD;
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wake_up(&ps2dev->wait);
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}
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return 1;
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}
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EXPORT_SYMBOL(ps2_handle_response);
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void ps2_cmd_aborted(struct ps2dev *ps2dev)
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{
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if (ps2dev->flags & PS2_FLAG_ACK)
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ps2dev->nak = 1;
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if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
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wake_up(&ps2dev->wait);
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ps2dev->flags = 0;
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}
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EXPORT_SYMBOL(ps2_cmd_aborted);
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