#include "serial.h"

/*
 * SERIAL_LINE_COMMAND_PORT configuration
 * Bit:     | 7 | 6 | 5 4 3 | 2 | 1 0 |
 * Content: | d | b | prty  | s | dl  |
 * d = enable/disable DLAB
 * b = enable/disable break control
 * prty = # of parity bits to use
 * s = # no of stop bits [0 is 1] and [1 is 1.5 or 2]
 * dl = length of data
 *
 */

void serial_set_baud_rate(const u16 com_port, const u16 divisor) {
	// Activate line - ready to send higher 8 bits of data
	// send the higher 8 bits first
	// send the lower 8 bits next

	serialport_write_byte(SERIAL_LINE_COMMAND_PORT(com_port), 
			SERIAL_LINE_ENABLE);

	serialport_write_byte(SERIAL_DATA_PORT(com_port), 
			(divisor>>8) & 0x00ff);

	serialport_write_byte(SERIAL_DATA_PORT(com_port), 
			divisor & 0x00ff);
}

// Payload described above
void serial_configure_line(const u16 line, const u8 payload) {
	serialport_write_byte(SERIAL_LINE_COMMAND_PORT(line), payload);
}


u8 serial_fifo_empty(const u16 com_port) {
	// we get back 0x20 if it is empty
	return serial_read_byte(SERIAL_LINE_STATUS_PORT(com_port)) & 
		SERIAL_FIFO_EMPTY_CODE;
}

u64 serial_write(const char* buffer, const u64 size) {
	/*
	 * Writes a given buffer to the com1 serial port for debugging in bochs
	 */
	serialport_write_byte(SERIAL_DATA_PORT_INT_EN(SERIAL_COM1_BASE), 
			0x00);

	serialport_write_byte(SERIAL_LINE_COMMAND_PORT(SERIAL_COM1_BASE), 
			SERIAL_LINE_ENABLE);

	// quarter speed hopefully the fifo quue wont fill this way
	serialport_write_byte(SERIAL_COM1_BASE, 
			0x01);

	serialport_write_byte(SERIAL_DATA_PORT_INT_EN(SERIAL_COM1_BASE),
			0x00);

	serialport_write_byte(SERIAL_LINE_COMMAND_PORT(SERIAL_COM1_BASE), 
			SERIAL_DEFAULT_LINE_CFG);

	serialport_write_byte(SERIAL_FIFO_COMMAND_PORT(SERIAL_COM1_BASE),
			SERIAL_DEFAULT_BUFFER_CFG);

	serialport_write_byte(SERIAL_MODEM_COMMAND_PORT(SERIAL_COM1_BASE),
			0x0B);

	u64 idx;
	for(idx =0; idx < size; idx++) {
		serialport_write_byte(SERIAL_COM1_BASE, buffer[idx]);
	}
	return idx;
}


void serial_pic_ack(u32 interrupt) {
	// ignore things that are too small and too big
	if(interrupt < PIC1_START_INT || interrupt > PIC2_END_INT) {
		return;
	}
	// Send acknoldgement to the pic that we have handled the interrupt
	// without this it literally just wait for the ack
	if(interrupt < PIC2_START_INT) {
		serialport_write_byte(PIC1_PORT, PIC_ACK);
	}
	else {
		serialport_write_byte(PIC2_PORT, PIC_ACK);
	}
}