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#include "uart_16550.h"
#include <sys/io.h>
int
uart_init(enum UART port)
{
outb(0x00, port + 1); // Disable all interrupts
outb(0x80, port + 3); // Enable DLAB (set baud rate divisor)
outb(0x03, port + 0); // Set divisor to 3 (lo byte) 38400 baud
outb(0x00, port + 1); // (hi byte)
outb(0x03, port + 3); // 8 bits, no parity, one stop bit
outb(0xc7, port + 2); // Enable FIFO, clear them, with 14-byte threshold
outb(0x0b, port + 4); // IRQs enabled, RTS/DSR set
outb(0x1e, port + 4); // Set in loopback mode, test the serial chip
outb(0xae, port + 0); // Test serial chip (send byte 0xAE and check if serial
// returns same byte)
// Check if serial is faulty (i.e: not same byte as sent)
if (inb(port + 0) != 0xae) {
return 1;
}
// If serial is not faulty set it in normal operation mode
// (not-loopback with IRQs enabled and OUT#1 and OUT#2 bits enabled)
outb(0x0f, port + 4);
return 0;
}
int
uart_thre(enum UART port)
{
return inb(port + LineStatus) & THRE;
}
void
uart_write(enum UART port, char a)
{
while (uart_thre(port) == 0)
;
outb(a, port);
if (a == '\n') {
while (uart_thre(port) == 0)
;
outb('\r', port);
}
}
int
uart_puts(enum UART port, const char *string, int length)
{
int written = 0;
if (length == -1)
while (*string != '\0') {
uart_write(port, *string);
++string;
++written;
}
else
for (int i = 0; i < length; ++i) {
uart_write(port, string[i]);
++written;
}
return written;
}
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