serial: enable or diable serial from grub

Author: edrflt

grub/grub.cfg

@@ -1,11 +1,21 @@
 timeout=2
 
-menuentry "elsOS (azerty)" {
+menuentry "elsOS with serial, azerty" {
+   multiboot2 /boot/elsos.bin serial
+   boot
+}
+
+menuentry "elsOS with serial, qwerty ansi" {
+   multiboot2 /boot/elsos.bin serial qwerty
+   boot
+}
+
+menuentry "elsOS, azerty" {
    multiboot2 /boot/elsos.bin
    boot
 }
 
-menuentry "elsOS (qwerty)" {
+menuentry "elsOS, qwerty ansi" {
    multiboot2 /boot/elsos.bin qwerty
    boot
 }

src/elsos.rs

@@ -21,22 +21,24 @@ static EXTRAVERSION: &str = env!("EXTRAVERSION");
 
 pub struct Settings
 {
+	has_serial: bool,
 	layout: u8
 }
 
 pub static mut SETTINGS: Settings = Settings
 {
+	has_serial: false,
 	layout: 0
 };
 
 #[no_mangle]
 pub extern "C" fn kernel_main(magic: u32, address: u32)
 {
 	init_vga();
-	init_serial();
 	vga::cursor::Cursor::init(0, 15);
 	if multiboot::check_magic(magic) && multiboot::parse(address)
 	{
+		init_serial();
 		logln!("\n");
 		logln!("        :::      ::::::::    __       __       __ _  ____  ____  ");
 		logln!("      :+:      :+:    :+:  .'  `'._.'`  '.    (  / )(  __)/ ___) ");

src/multiboot.rs

@@ -113,6 +113,14 @@ fn handle_qwerty()
 	}
 }
 
+fn handle_serial()
+{
+	unsafe
+	{
+		crate::SETTINGS.has_serial = true;
+	}
+}
+
 fn parse_args(args: &[u8])
 {
 	let mut previous_index: usize = 0;
@@ -129,6 +137,7 @@ fn parse_args(args: &[u8])
 			match arg
 			{
 				"qwerty" => handle_qwerty(),
+				"serial" => handle_serial(),
 				_ => {}
 			};
 

src/serial.rs

@@ -24,6 +24,13 @@ fn check_serial_chip(port: u32) -> bool
 
 pub fn init(port: u32) -> bool
 {
+	unsafe
+	{
+		if !crate::SETTINGS.has_serial
+		{
+			return false;
+		}
+	}
 	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) (115 200 / 3 => 38400 baud)
@@ -129,9 +136,16 @@ pub static mut W: Writer = Writer
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments)
 {
-	use core::fmt::Write;
 	unsafe
 	{
-		W.write_fmt(args).unwrap();
+		if !crate::SETTINGS.has_serial
+		{
+			return;
+		}
+		else
+		{
+			use core::fmt::Write;
+			W.write_fmt(args).unwrap();
+		}
 	}
 }