build: Bump uart_16550 from 0.4.0 to 0.6.0

Bumps [uart_16550](https://github.com/rust-osdev/uart_16550) from 0.4.0 to 0.6.0.
- [Release notes](https://github.com/rust-osdev/uart_16550/releases)
- [Changelog](https://github.com/rust-osdev/uart_16550/blob/v0.6.0/CHANGELOG.md)
- [Commits](rust-osdev/uart_16550@v0.4.0...v0.6.0)

---
updated-dependencies:
- dependency-name: uart_16550
  dependency-version: 0.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Cargo.lock

@@ -39,7 +39,7 @@ fdt = "0.1.5"
 chrono = { version = "0.4", default-features = false }
 
 [target.'cfg(target_arch = "x86_64")'.dependencies]
-uart_16550 = "0.4.0"
+uart_16550 = "0.6.0"
 x86_64 = { version = "0.15.4", default-features = false, features = [
     "instructions",
 ] }

Cargo.toml

@@ -180,7 +180,7 @@ fn boot_from_device(
 #[cfg(target_arch = "x86_64")]
 #[no_mangle]
 pub extern "C" fn rust64_start(#[cfg(not(feature = "coreboot"))] pvh_info: &pvh::StartInfo) -> ! {
-    serial::PORT.borrow_mut().init();
+    serial::init();
     logger::init();
 
     arch::x86_64::sse::enable_sse();
@@ -202,7 +202,7 @@ pub extern "C" fn rust64_start(x0: *const u8) -> ! {
     arch::aarch64::paging::setup();
 
     // Use atomic operation before MMU enabled may cause exception, see https://www.ipshop.xyz/5909.html
-    serial::PORT.borrow_mut().init();
+    serial::init();
     logger::init();
 
     let info = fdt::StartInfo::new(
@@ -225,7 +225,7 @@ pub extern "C" fn rust64_start(x0: *const u8) -> ! {
 pub extern "C" fn rust64_start(a0: u64, a1: *const u8) -> ! {
     use crate::bootinfo::{EntryType, Info, MemoryEntry};
 
-    serial::PORT.borrow_mut().init();
+    serial::init();
     logger::init();
 
     info!("Starting on RV64 0x{:x} 0x{:x}", a0, a1 as u64,);

src/main.rs

@@ -12,14 +12,14 @@ use atomic_refcell::AtomicRefCell;
 use crate::{arch::aarch64::layout::map, uart_pl011::Pl011 as UartPl011};
 
 #[cfg(target_arch = "x86_64")]
-use uart_16550::SerialPort as Uart16550;
+use uart_16550::{backend::PioBackend, Config, Uart16550Tty};
 
 #[cfg(target_arch = "riscv64")]
 use crate::uart_mmio::UartMmio;
 
 // We use COM1 as it is the standard first serial port.
 #[cfg(target_arch = "x86_64")]
-pub static PORT: AtomicRefCell<Uart16550> = AtomicRefCell::new(unsafe { Uart16550::new(0x3f8) });
+pub static PORT: AtomicRefCell<Option<Uart16550Tty<PioBackend>>> = AtomicRefCell::new(None);
 
 #[cfg(target_arch = "aarch64")]
 pub static PORT: AtomicRefCell<UartPl011> =
@@ -31,10 +31,41 @@ const SERIAL_PORT_ADDRESS: u64 = 0x1000_0000;
 #[cfg(target_arch = "riscv64")]
 pub static PORT: AtomicRefCell<UartMmio> = AtomicRefCell::new(UartMmio::new(SERIAL_PORT_ADDRESS));
 
+#[cfg(target_arch = "x86_64")]
+pub fn init() {
+    let mut port = PORT.borrow_mut();
+
+    if port.is_none() {
+        *port = Some(unsafe {
+            Uart16550Tty::new_port(0x3f8, Config::default())
+                .expect("Failed to initialize UART16550")
+        });
+    }
+}
+
+#[cfg(not(target_arch = "x86_64"))]
+pub fn init() {
+    PORT.borrow_mut().init();
+}
+
 pub struct Serial;
 impl fmt::Write for Serial {
     fn write_str(&mut self, s: &str) -> fmt::Result {
-        PORT.borrow_mut().write_str(s)
+        #[cfg(target_arch = "x86_64")]
+        {
+            let mut port = PORT.borrow_mut();
+
+            if let Some(port) = port.as_mut() {
+                return fmt::Write::write_str(port, s);
+            }
+
+            Ok(())
+        }
+
+        #[cfg(not(target_arch = "x86_64"))]
+        {
+            PORT.borrow_mut().write_str(s)
+        }
     }
 }