aarch64: add driver interfaces

kernel/src/arch/aarch64/board/raspi3/mod.rs

@@ -9,10 +9,16 @@ pub mod serial;
 pub const IO_REMAP_BASE: usize = bcm2837::IO_BASE;
 pub const IO_REMAP_END: usize = 0x40001000;
 
-pub fn init() {
+/// Some initializations must be done before other initializations.
+pub fn init_early() {
     assert_has_not_been_called!("board::init must be called only once");
 
     serial::SERIAL_PORT.lock().init();
 
     println!("Hello Raspberry Pi!");
 }
+
+/// Initialize raspi3 drivers
+pub fn init_driver() {
+    timer::init();
+}

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

@@ -0,0 +1,12 @@
+/// ARM64 drivers
+
+use once::*;
+
+use super::board;
+
+/// Initialize ARM64 common drivers
+pub fn init() {
+    assert_has_not_been_called!();
+
+    board::init_driver();
+}

kernel/src/arch/aarch64/mod.rs

@@ -6,29 +6,25 @@ pub mod memory;
 pub mod interrupt;
 pub mod consts;
 pub mod cpu;
+pub mod driver;
 
 #[cfg(feature = "board_raspi3")]
 #[path = "board/raspi3/mod.rs"]
 pub mod board;
 
-pub use self::board::timer;
-
 global_asm!(include_str!("boot/boot.S"));
 
 /// The entry point of kernel
 #[no_mangle] // don't mangle the name of this function
 pub extern "C" fn rust_main() -> ! {
-    // Enable mmu and paging
-    memory::init_mmu_early();
-
-    // Init board to enable serial port.
-    board::init();
+    memory::init_mmu_early(); // Enable mmu and paging
+    board::init_early();
     println!("{}", LOGO);
 
     crate::logging::init();
     interrupt::init();
     memory::init();
-    timer::init();
+    driver::init();
 
     crate::process::init();