Add ns16550a

os/src/drivers/chardev/mod.rs

@@ -0,0 +1,17 @@
+mod ns16550a;
+
+pub use ns16550a::NS16550a;
+
+use crate::board::CharDeviceImpl;
+use alloc::sync::Arc;
+use lazy_static::*;
+
+pub trait CharDevice {
+    fn read(&self) -> u8;
+    fn write(&self, ch: u8);
+    fn handle_irq(&self);
+}
+
+lazy_static! {
+    pub static ref UART: Arc<CharDeviceImpl> = Arc::new(CharDeviceImpl::new());
+}