kmain.c

#include "io.h"

/* The I/O ports */
#define FB_COMMAND_PORT         0x3D4
#define FB_DATA_PORT            0x3D5

/* The I/O port commands */
#define FB_HIGH_BYTE_COMMAND    14
#define FB_LOW_BYTE_COMMAND     15

#define SERIAL_COM1_BASE                0x3F8      /* COM1 base port */

#define SERIAL_DATA_PORT(base)          (base) /* Port du COM */
#define SERIAL_FIFO_COMMAND_PORT(base)  (base + 2) /* Port de commande du FIFO */
#define SERIAL_LINE_COMMAND_PORT(base)  (base + 3)  /* Port de commande de la ligne */
#define SERIAL_MODEM_COMMAND_PORT(base) (base + 4)  /* Port de commande du modem */
#define SERIAL_LINE_STATUS_PORT(base)   (base + 5)  /* Port d'état de la ligne */


/* The C function */
int sum_of_three(int arg1, int arg2, int arg3)
{
    return arg1 + arg2 + arg3;
}



/** fb_write_cell:
 *  Writes a character with the given foreground and background to position i
 *  in the framebuffer.
 *
 *  @param i  The location in the framebuffer
 *  @param c  The character
 *  @param fg The foreground color
 *  @param bg The background color
 */
void fb_write_cell(unsigned int i, char c, unsigned char fg, unsigned char bg)
{
    char *fb = (char *) 0x000B8000;

    fb[i] = c;
    fb[i + 1] = ((fg & 0x0F) << 4) | (bg & 0x0F);
}




/** fb_move_cursor:
 *  Moves the cursor of the framebuffer to the given position
 *
 *  @param pos The new position of the cursor
 */
void fb_move_cursor(unsigned short pos)
{
    outb(FB_COMMAND_PORT, FB_HIGH_BYTE_COMMAND);
    outb(FB_DATA_PORT,    ((pos >> 8) & 0x00FF));
    outb(FB_COMMAND_PORT, FB_LOW_BYTE_COMMAND);
    outb(FB_DATA_PORT,    pos & 0x00FF);
}


int write(char *buf, unsigned int len) {
    for(unsigned int i = 0; i < len; i++) {
        unsigned char fg = 0;
        unsigned char bg = 2;
        fb_write_cell(i*2, buf[i], fg, bg);
        fb_move_cursor(i+1);
    }
    return 0;
}


/* The I/O ports */

/* All the I/O ports are calculated relative to the data port. This is because
    * all serial ports (COM1, COM2, COM3, COM4) have their ports in the same
    * order, but they start at different values.
    */



/* The I/O port commands */

/* SERIAL_LINE_ENABLE_DLAB:
    * Tells the serial port to expect first the highest 8 bits on the data port,
    * then the lowest 8 bits will follow
    */
#define SERIAL_LINE_ENABLE_DLAB         0x80

/** serial_configure_baud_rate:
 *  Sets the speed of the data being sent. The default speed of a serial
 *  port is 115200 bits/s. The argument is a divisor of that number, hence
 *  the resulting speed becomes (115200 / divisor) bits/s.
 *
 *  @param com      The COM port to configure
 *  @param divisor  The divisor
 */
void serial_configure_baud_rate(unsigned short com, unsigned short divisor)
{
    outb(SERIAL_LINE_COMMAND_PORT(com),
            SERIAL_LINE_ENABLE_DLAB);
    outb(SERIAL_DATA_PORT(com),
            (divisor >> 8) & 0x00FF);
    outb(SERIAL_DATA_PORT(com),
            divisor & 0x00FF);
}


/** serial_configure_line:
 *  Configures the line of the given serial port. The port is set to have a
 *  data length of 8 bits, no parity bits, one stop bit and break control
 *  disabled.
 *
 *  @param com  The serial port to configure
 */
void serial_configure_line(unsigned short com)
{
    /* Bit:     | 7 | 6 | 5 4 3 | 2 | 1 0 |
        * Content: | d | b | prty  | s | dl  |
        * Value:   | 0 | 0 | 0 0 0 | 0 | 1 1 | = 0x03
        */
    outb(SERIAL_LINE_COMMAND_PORT(com), 0x03);
}

void serial_configure_fifi(unsigned short com) {
    outb(SERIAL_FIFO_COMMAND_PORT(com), 0xC7);
}

void serial_configure_modem(unsigned short com) {
    outb(SERIAL_MODEM_COMMAND_PORT(com), 0x03);
}

/** serial_is_transmit_fifo_empty:
 *  Checks whether the transmit FIFO queue is empty or not for the given COM
 *  port.
 *
 *  @param  com The COM port
 *  @return 0 if the transmit FIFO queue is not empty
 *          1 if the transmit FIFO queue is empty
 */
int serial_is_transmit_fifo_empty(unsigned int com)
{
    /* 0x20 = 0010 0000 */
    return inb(SERIAL_LINE_STATUS_PORT(com)) & 0x20;
}

void serial_write(char *buf, unsigned int len, unsigned short com) {
    for(unsigned int i = 0; i < len; i++) {
        while (serial_is_transmit_fifo_empty(SERIAL_DATA_PORT(com)) == 0); // On attend que fifo soit vide
        outb(SERIAL_DATA_PORT(com), buf[i]);
    }
}

// char serial_read(unsigned short com) { // Pas l'impression que ça marche
//     while ((inb(SERIAL_LINE_STATUS_PORT(com)) & 1) == 0);
//     return inb(SERIAL_DATA_PORT(com));
// }

void serial_init(unsigned short com) {
    serial_configure_baud_rate(com, 2);
    serial_configure_line(com);
    serial_configure_fifi(com);
    serial_configure_modem(com);
}