Nigel/BarinkOS
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Created a proper driver for the serial bus

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* The driver can write to any of the pre-defined serial COM ports
* The driver can read from any of the pre-defined serial COM ports (Untested)
This commit is contained in:
Nigel Barink 2023-10-28 21:51:04 +02:00
parent 2522492835
commit 9c5667c454
5 changed files with 87 additions and 89 deletions
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8
kernel/Makefile
View File

@ -34,7 +34,8 @@ OFILES = $(OBJ_DIR)/boot.o \
$(OBJ_DIR)/ataDevice.o \
$(OBJ_DIR)/rsdp.o \
$(OBJ_DIR)/acpi.o \
$(OBJ_DIR)/fat.o
$(OBJ_DIR)/fat.o \
$(OBJ_DIR)/serial.o
OBJ_LINK_LIST = $(CRTI_OBJ) $(CRTBEGIN_OBJ) $(OFILES) $(CRTEND_OBJ) $(CRTN_OBJ)
INTERNAL_OBJS = $(CRTI_OBJ) $(OFILES) $(CRTN_OBJ)
@ -121,6 +122,11 @@ $(OBJ_DIR)/processor.o:
$(OBJ_DIR)/fat.o:
$(CPP) -c storage/filesystems/FAT/FAT.cpp -o $(OBJ_DIR)/fat.o $(CFLAGS) -fno-exceptions -fno-rtti
$(OBJ_DIR)/serial.o:
$(CPP) -c drivers/serial/serial.cpp -o $(OBJ_DIR)/serial.o $(CFLAGS) -fno-exceptions -fno-rtti
# Assembly -> Object files
$(OBJ_DIR)/boot.o:
$(AS) boot/boot.s -o $(OBJ_DIR)/boot.o

53
kernel/drivers/serial/serial.cpp
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@ -1,19 +1,52 @@
#include "serial.h"
#include "../../io/io.h"
Serial Serial::init() {
// No clue what to setup yet!
// Initializes communication according to the spec given
Serial::Serial(SerialConfig config) {
port = config.port;
// Disable interrupts
outb(config.port + 1, 0x00);
return Serial();
// Enable DLAB
outb(config.port + 3, 0x80);
// set the baudrate
outb(config.port + 0, 0x03);
outb(config.port + 1, 0x00);
// configure for 8bits, no parity, one stop bit
outb(config.port + 3, 0x03);
// Enable FIFO, clear them, with 14-byte threshhold
outb(config.port + 2, 0xC7);
// Enable IRQ's, RTS/DSR set
outb(config.port + 4, 0x0B );
// Set in loopback mode, test the serial chip.
outb(config.port + 4, 0x1E);
// TEST
outb(config.port + 0 , 0xAE);
if(inb(config.port + 0) != 0xAE)
return ; // FAIL
outb(config.port + 4, 0x0F);
return ;
}
void Serial::print(){
// Do nothing!
void Serial::write(void* data, int len) {
while (is_transmit_empty() == 0); // Wait for transmit queue to be free
for (int i = 0; i < len ; i++){
outb(port, ((uint8_t*)data)[i]);
}
}
Serial::Serial(){
// Do nothing!
char Serial::read() {
return inb(port);
}
Serial::~Serial(){
// Do nothing!
}
int Serial::is_transmit_empty() {
return inb(port + 5) & 0x20;
}

34
kernel/drivers/serial/serial.h
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@ -1,19 +1,29 @@
#pragma once
// For now these are the standard
// serial ports we can talk to
enum SERIALPORT {
COM1 = 0x3F8,
COM2 = 0x2F8,
COM3 = 0x3E8,
COM4 = 0x2E8
};
class Serial {
struct SerialConfig {
SERIALPORT port;
char baud_rate_lo ;
char baud_rate_hi;
};
class Serial {
public:
static Serial init();
void print();
Serial (SerialConfig config );
private:
const int COM1 = 0x3F8;
const int COM2 = 0x2F8;
const int COM3 = 0x3E8;
const int COM4 = 0x2E8;
char read();
void write(void* data, int length);
Serial();
~Serial();
private:
SERIALPORT port;
int is_transmit_empty();
};

23
kernel/kernel.cpp
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@ -12,12 +12,11 @@
#include "i386/processor.h"
#include "terminal/kterm.h"
#include "interrupts/idt.h"
#include "serial.h"
#include "storage/vfs/vfs.h"
#include "storage/filesystems/FAT/FAT.h"
#include "acpi/acpi.h"
#include "memory/VirtualMemoryManager.h"
#include "drivers/serial/serial.h"
extern BootInfoBlock* BIB;
extern "C" void LoadGlobalDescriptorTable();
@ -40,20 +39,16 @@ void initBootDrive(){
extern "C" void kernel ()
{
init_serial();
kterm_init();
print_serial("kterm initialized...\n");
setup_tss();
initGDT();
initidt();
LoadGlobalDescriptorTable();
flush_tss();
printf("Memory setup complete!\n");
print_serial("Memory initialized....\n");
// Enable interrupts
asm volatile("STI");
initHeap();
print_serial("Heap initialized...\n");
//pit_initialise();
@ -64,11 +59,23 @@ extern "C" void kernel ()
initBootDrive();
VirtualFileSystem::initialize();
print_serial("Run test!");
// Test new serial driver
SerialConfig debug_com1_config{
COM1,
0x03,
0x00
};
Serial com1 = Serial(debug_com1_config);
com1.write((void*)"Hello world!\n", 14);
#define VFS_EXAMPLE
#ifdef VFS_EXAMPLE
auto fontFile = VirtualFileSystem::open("/FONT PSF", 0);
printf("Size of font file: %d bytes", fontFile->root->size); // COOL This Works like a charm
printf("Size of font file: %d bytes\n", fontFile->root->size); // COOL This Works like a charm
#endif
#ifdef USERMODE_RELEASE

58
kernel/serial.h
View File

@ -1,58 +0,0 @@
#pragma once
#include "terminal/kterm.h"
#include "io/io.h"
#define PORT 0x3f8
static int init_serial() {
#ifdef __VERBOSE__
printf("Init Serial\n");
#endif
outb(PORT + 1, 0x00); // Disable all interrupts
outb(PORT + 3, 0x80); // Enable DLAB (set baud rate divisor)
outb(PORT + 0, 0x03); // Set divisor to 3 (lo byte) 38400 baud
outb(PORT + 1, 0x00); // (hi byte)
outb(PORT + 3, 0x03); // 8 bits, no parity, one stop bit
outb(PORT + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold
outb(PORT + 4, 0x0B); // IRQs enabled, RTS/DSR set
outb(PORT + 4, 0x1E); // Set in loopback mode, test the serial chip
outb(PORT + 0, 0xAE); // 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(PORT + 4, 0x0F);
return 0;
}
inline int is_transmit_empty() {
return inb(PORT + 5) & 0x20;
}
inline void write_serial(char a) {
while (is_transmit_empty() == 0);
outb(PORT,a);
}
inline int serial_received() {
return inb(PORT + 5) & 1;
}
inline char read_serial() {
while (serial_received() == 0);
return inb(PORT);
}
inline void print_serial(const char* string ){
for(size_t i = 0; i < strlen(string); i ++){
write_serial(string[i]);
}
}