fix: bcm2837 serial

Makefile

@@ -45,6 +45,7 @@ endif
 ifeq ($(MACH),rpi3)
 QEMU_OPTS+=-kernel $(O)/kernel.bin \
 		   -initrd $(O)/initrd.img \
+		   -dtb etc/bcm2837-rpi-3-b-plus.dtb \
 		   -M raspi3b \
 		   -serial mon:stdio \
 		   -display none \

kernel/src/arch/aarch64/mach_rpi3/mod.rs

@@ -4,6 +4,7 @@ use crate::dev::{
     serial::{pl011::Pl011, SerialDevice},
     Device,
 };
+use crate::fs::devfs::{self, CharDeviceType};
 use crate::mem::phys;
 use libsys::error::Errno;
 
@@ -37,6 +38,7 @@ pub fn init_board() -> Result<(), Errno> {
     unsafe {
         IRQCHIP.enable()?;
         UART.init_irqs()?;
+        devfs::add_char_device(&UART, CharDeviceType::TtySerial)?;
 
         EMMC.enable()?;
     }

kernel/src/util.rs

@@ -71,6 +71,6 @@ macro_rules! block {
     }};
 
     ($cond:expr, $timeout:expr) => {
-        crate::block!($cond, $timeout, return Err(error::Errno::TimedOut))
+        crate::block!($cond, $timeout, return Err(libsys::error::Errno::TimedOut))
     };
 }