i8042.c

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#include <core/system.h>
#include <core/string.h>
#include <core/kargs.h>
#include <core/module.h>
#include <cpu/io.h>
#include <dev/irq.h>
#include <dev/platform.h>
#include <dev/i8042.h>
#include <aquila/errno.h>
 
static struct ioaddr i8042_ioaddr;
static int i8042_found;
 
/* the handler of each port's bytes */
static void (*port_handler[2])(int);
 
#define DATA_PORT        0x00
#define STATUS_PORT      0x04
#define COMMAND_PORT     0x04
 
#define STATUS_OBUF_FULL 0x01
#define STATUS_IBUF_FULL 0x02
#define STATUS_SYSTEM    0x04
#define STATUS_COMMAND   0x08
#define STATUS_TOUT      0x40
#define STATUS_PARITY    0x80

static uint8_t read_status(void)
{
    return io_in8(&i8042_ioaddr, STATUS_PORT);
}

static int has_byte(void)
{
    return read_status() & STATUS_OBUF_FULL;
}

static void i8042_irq(void *arg)
{
    void (**handler)(int) = arg;
 
    if (!has_byte())
        return;
 
    int byte = io_in8(&i8042_ioaddr, DATA_PORT);
 
    if (*handler)
        (*handler)(byte);
}

void i8042_handler_register(int port, void (*fun)(int))
{
    if (port == 1 || port == 2)
        port_handler[port - 1] = fun;
}

static int write_wait(void)
{
    for (int i = 0; i < 100000; ++i)
        if (!(read_status() & STATUS_IBUF_FULL))
            return 0;
 
    return -ETIMEDOUT;
}

int i8042_aux_write(uint8_t byte)
{
    if (!i8042_found)
        return -ENODEV;
 
    int err = write_wait();
 
    if (err)
        return err;
 
    io_out8(&i8042_ioaddr, COMMAND_PORT, 0xD4);
 
    if ((err = write_wait()))
        return err;
 
    io_out8(&i8042_ioaddr, DATA_PORT, byte);
    return 0;
}

void i8042_reboot(void)
{
    if (i8042_found)
        io_out8(&i8042_ioaddr, COMMAND_PORT, 0xFE);
}

static int read_wait(void)
{
    for (int i = 0; i < 100000; ++i)
        if (has_byte())
            return io_in8(&i8042_ioaddr, DATA_PORT);
 
    return -ETIMEDOUT;
}
 
#define CMD_READ_CONFIG   0x20
#define CMD_WRITE_CONFIG  0x60
#define CMD_AUX_ENABLE    0xA8
#define CONFIG_AUX_IRQ    0x02

static int aux_enable(void)
{
    int err, config;
 
    if ((err = write_wait()))
        return err;
 
    io_out8(&i8042_ioaddr, COMMAND_PORT, CMD_AUX_ENABLE);
 
    if ((err = write_wait()))
        return err;
 
    io_out8(&i8042_ioaddr, COMMAND_PORT, CMD_READ_CONFIG);
 
    if ((config = read_wait()) < 0)
        return config;
 
    if ((err = write_wait()))
        return err;
 
    io_out8(&i8042_ioaddr, COMMAND_PORT, CMD_WRITE_CONFIG);
 
    if ((err = write_wait()))
        return err;
 
    io_out8(&i8042_ioaddr, DATA_PORT, config | CONFIG_AUX_IRQ);
    return 0;
}

static int i8042_init(void)
{
    const struct platform_device *pd = platform_device_get("i8042", 0);
 
    if (!pd)
        return -ENODEV;
 
    int err = platform_device_io(pd, &i8042_ioaddr);
 
    if (err)
        return err;
 
    /* the controller should say it passed its self-test; with the
     * i8042.nocheck argument, that isn't checked */
    if (kargs_get("i8042.nocheck", NULL)) {
        if (!(read_status() & STATUS_SYSTEM)) {
            printk("i8042: controller not found\n");
            return -ENODEV;
        }
    } else {
        printk("i8042: skipping check\n");
    }
 
    i8042_found = 1;
    printk("i8042: controller at %p (%s)\n", (void *) pd->io.addr, ioaddr_type_str(&i8042_ioaddr));
 
    /* the mouse's port, if the platform gives it an interrupt */
    if (pd->nirq > 1 && aux_enable())
        printk("i8042: the second port didn't come on\n");
 
    /* drop any bytes waiting from before */
    for (int i = 0; i < 10; ++i)
        io_in8(&i8042_ioaddr, DATA_PORT);
 
    for (int i = 0; i < pd->nirq && i < 2; ++i)
        irq_install(pd->irq[i], i8042_irq, &port_handler[i]);
 
    return 0;
}
 
MODULE_INIT(i8042, i8042_init, NULL)