os/stuff/drivers/i386/serial.c
2019-05-25 10:05:36 -05:00

160 lines
3.3 KiB
C

#include "../../cpu/i386/ports.h"
#include "../../cpu/i386/isr.h"
#include "../serial.h"
#include <stdio.h>
#include <string.h>
#include <devbuf.h>
#include "../vga.h"
#include "../../fs/devfs.h"
#include <klog.h>
#include <stdint.h>
#define SERIAL_LINE_ENABLE_DLAB 0x80
static devbuf* bufs[4];
static int data_port(int com) {
switch (com) {
case 0: return 0x3f8;
case 1: return 0x2f8;
case 2: return 0x3e8;
case 3: return 0x2e8;
}
return 0;
}
static int int_port(int com) {
switch (com) {
case 0: return 0x3f9;
case 1: return 0x2f9;
case 2: return 0x3e9;
case 3: return 0x2e9;
}
return 0;
}
static int fifo_port(int com) {
switch (com) {
case 0: return 0x3fa;
case 1: return 0x2fa;
case 2: return 0x3ea;
case 3: return 0x2ea;
}
return 0;
}
static int line_cmd_port(int com) {
switch (com) {
case 0: return 0x3fb;
case 1: return 0x2fb;
case 2: return 0x3eb;
case 3: return 0x2eb;
}
return 0;
}
static int modem_port(int com) {
switch (com) {
case 0: return 0x3fc;
case 1: return 0x2fc;
case 2: return 0x3ec;
case 3: return 0x2ec;
}
return 0;
}
static int line_stat_port(int com) {
switch (com) {
case 0: return 0x3fd;
case 1: return 0x2fd;
case 2: return 0x3ed;
case 3: return 0x2ed;
}
return 0;
}
static int scratch_port(int com) {
switch (com) {
case 0: return 0x3ff;
case 1: return 0x2ff;
case 2: return 0x3ef;
case 3: return 0x2ef;
}
return 0;
}
static void configure_baud_rate(uint32_t divisor,int com) {
port_byte_out(line_cmd_port(com),SERIAL_LINE_ENABLE_DLAB);
port_byte_out(data_port(com),(divisor>>8)&0xFF);
port_byte_out(data_port(com),divisor&0xFF);
}
static int is_transmit_fifo_empty(int com) {
return port_byte_in(line_stat_port(com))&0x20;
}
static void configure(uint32_t com, uint32_t rate) {
configure_baud_rate(115200/rate,com);
port_byte_out(line_cmd_port(com),0x03);
port_byte_out(fifo_port(com),0xC7);
port_byte_out(modem_port(com),0x03);
port_byte_out(int_port(com),0x01);
}
static int drv(char* filename,int c,long pos,char wr) {
int com;
switch (filename[4]) {
case '0':
com=0;
break;
case '1':
com=1;
break;
case '2':
com=2;
break;
case '3':
com=3;
break;
}
if (wr) {
while (!is_transmit_fifo_empty(com)) continue;
port_byte_out(data_port(com),c);
return 0;
} else {
return devbuf_get(bufs[com]);
}
}
void serial_int_handler_1(registers_t regs) {
char data=port_byte_in(data_port(0));
if (data=='\r') {
data='\n';
}
devbuf_add(data,bufs[0]);
}
void serial_int_handler_2(registers_t regs) {
devbuf_add(port_byte_in(data_port(1)),bufs[1]);
}
void serial_init() {
klog("INFO","Scanning for serial ports");
for (int i=0;i<2;i++) {
port_byte_out(scratch_port(i),0xaa);
if (port_byte_in(scratch_port(i))==0xaa) {
klog("INFO","Found COM%d",i+1);
bufs[i]=devbuf_init();
switch (i) {
case 0:
isr_register_handler(IRQ4,serial_int_handler_1);
configure(0,9600);
devfs_add(drv,"ttyS0");
break;
case 1:
isr_register_handler(IRQ3,serial_int_handler_2);
configure(1,9600);
devfs_add(drv,"ttyS1");
}
}
}
}