path: root/device/serial.c

#include "device/serial.h"
#include "device/uart.h"
#include "jove.h"

serial_dev_t COM1;

serial_dev_t 
serial_new(uint16_t com)
{
    serial_dev_t dev = { .com = com };
    serial_set_int(&dev, false);
    serial_set_baud(&dev, 3);
    serial_set_lcr(&dev, 1 | 2);
    serial_set_fcr(&dev, 1 | 2 | 4 | 0xC0);
    serial_set_fcr(&dev, 1 | 2 | 8);
    serial_set_mcr(&dev, 1 | 2 | 4 | 8);
    return dev;
}

void
serial_set_int(serial_dev_t *dev, bool enable)
{
    poutb(SERIAL_UART_COM_IER(dev->com), enable);
}

void
serial_set_baud(serial_dev_t *dev, uint16_t baud)
{
    /* Enable DLAB. */
    poutb(SERIAL_UART_COM_LCR(dev->com), SERIAL_UART_COM_LCR(dev->com) | 0x80);
    /* Write low & high bits. */
    poutb(SERIAL_UART_COM_DLAB_DLL(dev->com), baud & 0xFF);
    poutb(SERIAL_UART_COM_DLAB_DLH(dev->com), (baud >> 8) & 0xFF);
    /* Disable DLAB. */
    poutb(SERIAL_UART_COM_LCR(dev->com), SERIAL_UART_COM_LCR(dev->com) & 0x7F);
}

void
serial_set_fcr(serial_dev_t *dev, uint16_t flg)
{
    poutb(SERIAL_UART_COM_FCR(dev->com), flg);
}

void
serial_set_lcr(serial_dev_t *dev, uint16_t flg)
{
    poutb(SERIAL_UART_COM_LCR(dev->com), flg);
}

void
serial_set_mcr(serial_dev_t *dev, uint16_t flg)
{
    poutb(SERIAL_UART_COM_MCR(dev->com), flg);
}

uint8_t
serial_line_status(serial_dev_t *dev)
{
    return pinb(SERIAL_UART_COM_LSR(dev->com));
}

void
serial_write(serial_dev_t *dev, const char *s, size_t len)
{
    for(; len > 0; len--) {
        char c = *(s++);
        while((serial_line_status(dev) & 0x20) == 0) {}
        if(c == '\n') poutb(dev->com, '\r');
        poutb(dev->com, c);
    }
}

void
serial_setup(void)
{
    COM1 = serial_new(SERIAL_UART_COM1);
}