From ad877e5ca439b5ce9f54c1673b2bcc9607db828f Mon Sep 17 00:00:00 2001
From: littleblack111 <littleblack11111@gmail.com>
Date: Sun, 6 Sep 2026 19:14:52 +0800
Subject: refactor: earlyprintk and uart_16550

---
 kernel/src/init/earlyprintk.rs            | 24 ++++++++++----
 kernel/src/io/output/serial/uart_16550.rs | 55 +++++++------------------------
 2 files changed, 30 insertions(+), 49 deletions(-)

(limited to 'kernel')

diff --git a/kernel/src/init/earlyprintk.rs b/kernel/src/init/earlyprintk.rs
index 01c50fa..a217a92 100644
--- a/kernel/src/init/earlyprintk.rs
+++ b/kernel/src/init/earlyprintk.rs
@@ -1,17 +1,26 @@
 use spin::{lazylock::LazyLock, mutex::Mutex};
 
-use crate::io::output::serial::uart_16550::{SerialPortBitMask, Uart16550};
+use crate::io::output::serial::uart_16550::Uart16550;
 
 // TODO: use linkme instead
-pub static EARLY_PRINTK_SERIAL: LazyLock<Mutex<Uart16550>> = LazyLock::new(|| {
-    Mutex::new(unsafe { Uart16550::init(SerialPortBitMask::COM1, [const { None }; 4]).unwrap() })
-});
+pub static EARLY_PRINTK_SERIAL: LazyLock<Option<Mutex<Uart16550>>> =
+    LazyLock::new(|| match unsafe { Uart16550::init([const { None }; 4]) } {
+        Ok(o) => Some(Mutex::new(o)),
+        Err(_) => None,
+    });
 
 #[macro_export]
+// TODO: configurable via option or arguments
+// or use a system similar to the drivers(`linkme`)
 macro_rules! printk {
 	($($arg:tt)*) => ({
 		use ::core::fmt::Write;
-		write!($crate::init::earlyprintk::EARLY_PRINTK_SERIAL.lock().coms[0].as_mut().unwrap(), $($arg)*)
+		match &*$crate::init::earlyprintk::EARLY_PRINTK_SERIAL {
+			// TODO: elim the unwrap
+			Some(m) => write!(m.lock().coms[0].as_mut().unwrap(), $($arg)*),
+			// TODO: if needed find a way to return an error here, but for now just ignore it
+			None => Ok(()),
+		}
 	});
 }
 
@@ -19,6 +28,9 @@ macro_rules! printk {
 macro_rules! printkln {
 	($($arg:tt)*) => ({
 		use ::core::fmt::Write;
-		writeln!($crate::init::earlyprintk::EARLY_PRINTK_SERIAL.lock().coms[0].as_mut().unwrap(), $($arg)*)
+		match &*$crate::init::earlyprintk::EARLY_PRINTK_SERIAL {
+			Some(m) => writeln!(m.lock().coms[0].as_mut().unwrap(), $($arg)*),
+			None => Ok(()),
+		}
 	});
 }
diff --git a/kernel/src/io/output/serial/uart_16550.rs b/kernel/src/io/output/serial/uart_16550.rs
index 65ba4e9..3ecce1b 100644
--- a/kernel/src/io/output/serial/uart_16550.rs
+++ b/kernel/src/io/output/serial/uart_16550.rs
@@ -1,4 +1,3 @@
-use bitflags::bitflags;
 use uart_16550::{
     Config, Uart16550Tty, Uart16550TtyError,
     backend::{PioBackend, PortIoAddress},
@@ -13,15 +12,6 @@ pub enum SerialPortAddress {
     Com4 = 0x2E8,
 }
 
-bitflags! {
-    pub struct SerialPortBitMask: u8 {
-        const COM1 = 1 << 0;
-        const COM2 = 1 << 1;
-        const COM3 = 1 << 2;
-        const COM4 = 1 << 3;
-    }
-}
-
 impl From<SerialPortAddress> for u16 {
     fn from(value: SerialPortAddress) -> Self {
         value as u16
@@ -32,6 +22,14 @@ pub struct Uart16550 {
     pub coms: [Option<Uart16550Tty<PioBackend>>; 4],
 }
 
+#[inline(always)]
+fn init_port(
+    cfg: &mut Option<Config>,
+    addr: SerialPortAddress,
+) -> Result<Option<Uart16550Tty<PioBackend>>, Uart16550TtyError<PortIoAddress>> {
+    cfg.take().map(|c| unsafe { Uart16550Tty::new_port(addr.into(), c) }).transpose()
+}
+
 impl Uart16550 {
     /// # Safety
     ///
@@ -42,44 +40,15 @@ impl Uart16550 {
     ///
     /// [`NUM_REGISTERS`]: crate::spec::NUM_REGISTERS
     pub unsafe fn init(
-        coms_enabled: SerialPortBitMask,
         mut config: [Option<Config>; 4],
     ) -> Result<Self, Uart16550TtyError<PortIoAddress>> {
         unsafe {
             Ok(Self {
                 coms: [
-                    if coms_enabled.contains(SerialPortBitMask::COM1) {
-                        Some(Uart16550Tty::new_port(
-                            SerialPortAddress::COM1.into(),
-                            config[0].take().unwrap_or_default(),
-                        )?)
-                    } else {
-                        None
-                    },
-                    if coms_enabled.contains(SerialPortBitMask::COM2) {
-                        Some(Uart16550Tty::new_port(
-                            SerialPortAddress::Com2.into(),
-                            config[1].take().unwrap_or_default(),
-                        )?)
-                    } else {
-                        None
-                    },
-                    if coms_enabled.contains(SerialPortBitMask::COM3) {
-                        Some(Uart16550Tty::new_port(
-                            SerialPortAddress::Com3.into(),
-                            config[2].take().unwrap_or_default(),
-                        )?)
-                    } else {
-                        None
-                    },
-                    if coms_enabled.contains(SerialPortBitMask::COM4) {
-                        Some(Uart16550Tty::new_port(
-                            SerialPortAddress::Com4.into(),
-                            config[3].take().unwrap_or_default(),
-                        )?)
-                    } else {
-                        None
-                    },
+                    init_port(&mut config[0], SerialPortAddress::COM1)?,
+                    init_port(&mut config[1], SerialPortAddress::Com2)?,
+                    init_port(&mut config[2], SerialPortAddress::Com3)?,
+                    init_port(&mut config[3], SerialPortAddress::Com4)?,
                 ],
             })
         }
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