source: mainline/kernel/genarch/src/drivers/i8042/i8042.c

/*
 * Copyright (c) 2009 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup kernel_genarch
 * @{
 */
/**
 * @file
 * @brief i8042 processor driver
 *
 * It takes care of the i8042 serial communication.
 *
 */

#include <assert.h>
#include <genarch/drivers/i8042/i8042.h>
#include <genarch/drivers/legacy/ia32/io.h>
#include <arch/asm.h>
#include <console/chardev.h>
#include <stdlib.h>
#include <time/delay.h>

#define i8042_SET_COMMAND  0x60
#define i8042_COMMAND      0x69
#define i8042_CPU_RESET    0xfe

#define i8042_BUFFER_FULL_MASK  0x01
#define i8042_WAIT_MASK         0x02

#define i8042_TIMEOUT  65536

static irq_ownership_t i8042_claim(irq_t *irq)
{
        i8042_instance_t *i8042_instance = irq->instance;
        i8042_t *dev = i8042_instance->i8042;

        if (pio_read_8(&dev->status) & i8042_BUFFER_FULL_MASK)
                return IRQ_ACCEPT;
        else
                return IRQ_DECLINE;
}

static void i8042_irq_handler(irq_t *irq)
{
        i8042_instance_t *instance = irq->instance;
        i8042_t *dev = instance->i8042;

        if (pio_read_8(&dev->status) & i8042_BUFFER_FULL_MASK) {
                uint8_t data = pio_read_8(&dev->data);
                indev_push_character(instance->kbrdin, data);
        }
}

/** Clear input buffer. */
static void i8042_clear_buffer(i8042_t *dev)
{
        for (uint32_t i = 0; i < i8042_TIMEOUT; i++) {
                if ((pio_read_8(&dev->status) & i8042_BUFFER_FULL_MASK) == 0)
                        break;

                (void) pio_read_8(&dev->data);
                delay(50);  /* 50 us think time */
        }
}

static void i8042_send_command(i8042_t *dev, uint8_t cmd)
{
        for (uint32_t i = 0; i < i8042_TIMEOUT; i++) {
                if ((pio_read_8(&dev->status) & i8042_WAIT_MASK) == 0)
                        break;

                delay(50);  /* 50 us think time */
        }

        pio_write_8(&dev->status, cmd);
        delay(10000);  /* 10 ms think time */
}

/** Initialize i8042. */
i8042_instance_t *i8042_init(i8042_t *dev, inr_t inr)
{
        i8042_instance_t *instance =
            malloc(sizeof(i8042_instance_t));
        if (instance) {
                instance->i8042 = dev;
                instance->kbrdin = NULL;

                irq_initialize(&instance->irq);
                instance->irq.inr = inr;
                instance->irq.claim = i8042_claim;
                instance->irq.handler = i8042_irq_handler;
                instance->irq.instance = instance;
        }

        return instance;
}

void i8042_wire(i8042_instance_t *instance, indev_t *kbrdin)
{
        assert(instance);
        assert(kbrdin);

        i8042_clear_buffer(instance->i8042);

        instance->kbrdin = kbrdin;
        irq_register(&instance->irq);
}

/* Reset CPU by pulsing pin 0 */
void i8042_cpu_reset(i8042_t *dev)
{
        interrupts_disable();
        i8042_clear_buffer(dev);
        i8042_send_command(dev, i8042_CPU_RESET);
}

/** @}
 */