refactor: unsafe only in adapter + libkos; forbid(unsafe_code) everywhere else; libkos Window (volatile, bounds-checked MMIO/DMA/shared mem), entry!, thread::spawn; MapRegion returns pages; kernel const-built (with_cores/install_platform); newtype addrs

crates/drivers/input/uart/src/lib.rs

@@ -1,33 +1,33 @@
 #![no_std]
+#![forbid(unsafe_code)]
 
+use libkos::Window;
 use port_input_device::{InputDevice, InputEvent, Key};
+use types::address::VirtualAddress;
 
-const UART_VA: usize = 0x20000;
+const UART_VA: VirtualAddress = VirtualAddress::from_raw(0x20000);
 const UART_IER_OFFSET: usize = 1;
 const UART_LSR_OFFSET: usize = 5;
 /// IER bit: interrupt when a received byte is waiting (cleared by reading
 /// it, so `acknowledge` has nothing to do).
 const IER_RX_READY: u8 = 1;
 
-pub struct UartInputDevice;
+/// The UART's registers, one byte each.
+pub struct UartInputDevice {
+    regs: Window,
+}
 
 impl UartInputDevice {
     /// Maps the 16550 UART whose region `mmio` names and enables its
     /// receive interrupt.
     pub fn new(mmio: types::bounded::CapSlot) -> Option<Self> {
-        libkos::device::map_mmio(mmio, UART_VA).ok()?;
-        // SAFETY: UART_VA now maps the UART's registers.
-        unsafe { core::ptr::write_volatile((UART_VA + UART_IER_OFFSET) as *mut u8, IER_RX_READY) };
-        Some(Self)
+        let regs = libkos::device::map_mmio(mmio, UART_VA).ok()?;
+        regs.write(UART_IER_OFFSET, IER_RX_READY);
+        Some(Self { regs })
     }
 
     fn read_byte(&self) -> Option<u8> {
-        let lsr = unsafe { core::ptr::read_volatile((UART_VA + UART_LSR_OFFSET) as *const u8) };
-        if lsr & 1 != 0 {
-            Some(unsafe { core::ptr::read_volatile(UART_VA as *const u8) })
-        } else {
-            None
-        }
+        self.has_event().then(|| self.regs.read(0))
     }
 
     fn byte_to_key(byte: u8) -> Key {
@@ -50,7 +50,6 @@ impl InputDevice for UartInputDevice {
     }
 
     fn has_event(&self) -> bool {
-        let lsr = unsafe { core::ptr::read_volatile((UART_VA + UART_LSR_OFFSET) as *const u8) };
-        lsr & 1 != 0
+        self.regs.read::<u8>(UART_LSR_OFFSET) & 1 != 0
     }
 }