diff --git a/kernel/src/arch/aarch64/boot/mod.rs b/kernel/src/arch/aarch64/boot/mod.rs
index db46a27..1c3a8b4 100644
--- a/kernel/src/arch/aarch64/boot/mod.rs
+++ b/kernel/src/arch/aarch64/boot/mod.rs
@@ -1,10 +1,10 @@
 //! aarch64 common boot logic
 
-use crate::arch::aarch64::asm::{CPACR_EL1};
-use cortex_a::registers::{VBAR_EL1, SCTLR_EL1};
-use tock_registers::interfaces::{Writeable, ReadWriteable};
-
+use crate::arch::{aarch64::asm::CPACR_EL1, machine};
+use crate::dev::{Device, serial::SerialDevice, timer::TimestampSource};
 use cortex_a::asm::barrier::{self, dsb, isb};
+use cortex_a::registers::{SCTLR_EL1, VBAR_EL1};
+use tock_registers::interfaces::{ReadWriteable, Writeable};
 
 #[no_mangle]
 fn __aa64_bsp_main() {
@@ -21,44 +21,25 @@ fn __aa64_bsp_main() {
         dsb(barrier::SY);
         isb(barrier::SY);
 
-        SCTLR_EL1.modify(SCTLR_EL1::I::SET +
-                         SCTLR_EL1::SA::SET +
-                         SCTLR_EL1::C::SET +
-                         SCTLR_EL1::A::SET);
+        SCTLR_EL1
+            .modify(SCTLR_EL1::I::SET + SCTLR_EL1::SA::SET + SCTLR_EL1::C::SET + SCTLR_EL1::A::SET);
 
         dsb(barrier::SY);
         isb(barrier::SY);
     }
 
-    debugln!("Test");
+    machine::init_board().unwrap();
 
-    let mut el: u64;
-    let mut sctlr_el1: u64;
     unsafe {
-        asm!("mrs {}, currentel", out(reg) el);
-        asm!("mrs {}, sctlr_el1", out(reg) sctlr_el1);
+        machine::local_timer().lock().enable().unwrap();
     }
-    el >>= 2;
-    el &= 0x3;
 
-    debugln!("Current EL = {}", el);
-    debugln!("SCTLR_EL1 = {:#x}", sctlr_el1);
-
-    //use crate::arch::machine;
-    //use crate::dev::{serial::SerialDevice, timer::TimestampSource, Device};
-
-    //unsafe {
-        //machine::console().lock().enable().unwrap();
-        //machine::local_timer().lock().enable().unwrap();
-    //}
-
-    //let base = machine::local_timer().lock().timestamp().unwrap();
+    let base = machine::local_timer().lock().timestamp().unwrap();
 
     loop {
-        cortex_a::asm::wfe();
-        //let count = machine::local_timer().lock().timestamp().unwrap();
-        //let ch = machine::console().lock().recv(true).unwrap();
-        //debugln!("[{:?}] {:#04x} = '{}'!", count - base, ch, ch as char);
+        let count = machine::local_timer().lock().timestamp().unwrap();
+        let ch = machine::console().lock().recv(true).unwrap();
+        debugln!("[{:?}] {:#04x} = '{}'!", count - base, ch, ch as char);
     }
 }
 
diff --git a/kernel/src/arch/aarch64/boot/uboot.S b/kernel/src/arch/aarch64/boot/uboot.S
index 8ba2611..d8971c6 100644
--- a/kernel/src/arch/aarch64/boot/uboot.S
+++ b/kernel/src/arch/aarch64/boot/uboot.S
@@ -1,16 +1,25 @@
 // vi:ft=a64asm.asm:
 
-.set UART0_BASE,    0x05000000
+.set SCTLR_EL2_RES1,        0x30C50830
 
-.set SPSR_EL2_EL1h, 0x5
-.set HCR_EL2_RW,    1 << 31
-.set HCR_EL2_HCD,   1 << 29
+.set SPSR_EL2_EL1h,         0x5
+.set SPSR_EL2_MASK_DAIF,    0xF << 6
+.set HCR_EL2_RW,            1 << 31
+.set HCR_EL2_HCD,           1 << 29
+
+.set CNTHCTL_EL2_EL1PCEN,   1 << 1
+.set CNTHCTL_EL2_EL1PCTEN,  1 << 0
 
 .macro ADR_REL reg, sym
     adrp \reg, \sym
     add \reg, \reg, #:lo12:\sym
 .endm
 
+.macro MOV_L reg, value
+    mov \reg, #((\value) & 0xFFFF)
+    movk \reg, #((\value) >> 16), lsl #16
+.endm
+
 .section .text._entry
 .global _entry
 _entry:
@@ -19,16 +28,27 @@ _entry:
     lsr x0, x0, #2
     cmp x0, #2
     bne 1f
+
     // Exit EL2
-    // TODO cnthtctl_el2 setup
+    mrs x0, cnthctl_el2
+    orr x0, x0, #(CNTHCTL_EL2_EL1PCTEN | CNTHCTL_EL2_EL1PCEN)
+    msr cnthctl_el2, x0
+    msr cntvoff_el2, xzr
+
+    MOV_L x0, SCTLR_EL2_RES1
+    msr sctlr_el2, x0
+
+    mov x0, #HCR_EL2_RW
+    msr hcr_el2, x0
+
+    mov x0, #SPSR_EL2_EL1h
+    orr x0, x0, #SPSR_EL2_MASK_DAIF
+    msr spsr_el2, x0
 
     ADR_REL x0, 1f
     msr elr_el2, x0
-    mov x0, #SPSR_EL2_EL1h
-    msr spsr_el2, x0
-    mov x0, #(HCR_EL2_RW | HCR_EL2_HCD)
-    msr hcr_el2, x0
 
+    isb
     eret
 1:
     dsb sy
@@ -37,7 +57,9 @@ _entry:
     ADR_REL x0, bsp_stack_top
     mov sp, x0
 
-    b __aa64_bsp_main
+    mov lr, xzr
+    bl __aa64_bsp_main
+    b .
 
 .section .bss
 .p2align 12
diff --git a/kernel/src/arch/aarch64/mach_orangepi3/gpio.rs b/kernel/src/arch/aarch64/mach_orangepi3/gpio.rs
new file mode 100644
index 0000000..9edfdb1
--- /dev/null
+++ b/kernel/src/arch/aarch64/mach_orangepi3/gpio.rs
@@ -0,0 +1,111 @@
+use crate::arch::MemoryIo;
+use crate::dev::{
+    gpio::{GpioDevice, PinConfig, PinMode, PullMode},
+    Device,
+};
+use error::Errno;
+use tock_registers::interfaces::{Readable, Writeable};
+use tock_registers::register_structs;
+use tock_registers::registers::ReadWrite;
+
+pub const PH0_UART0_TX: u32 = 2;
+pub const PH1_UART0_RX: u32 = 2;
+
+register_structs! {
+    #[allow(non_snake_case)]
+    Regs {
+        (0x00 => CFG: [ReadWrite<u32>; 4]),
+        (0x10 => DAT: ReadWrite<u32>),
+        (0x14 => DRV: [ReadWrite<u32>; 2]),
+        (0x1C => PUL: [ReadWrite<u32>; 2]),
+        (0x24 => @END),
+    }
+}
+
+pub(super) struct Gpio {
+    regs: MemoryIo<Regs>,
+}
+
+impl Device for Gpio {
+    fn name() -> &'static str {
+        "Allwinner H6 GPIO Controller"
+    }
+
+    unsafe fn enable(&mut self) -> Result<(), Errno> {
+        Ok(())
+    }
+}
+
+impl GpioDevice for Gpio {
+    unsafe fn set_pin_config(&mut self, pin: u32, cfg: &PinConfig) -> Result<(), Errno> {
+        let pull = match cfg.pull {
+            PullMode::None => 0,
+            PullMode::Up => 1,
+            PullMode::Down => 2,
+        };
+
+        match cfg.mode {
+            PinMode::Disable => self.set_pin_cfg_inner(pin, 7),
+            PinMode::Input => {
+                self.set_pin_cfg_inner(pin, 0);
+                self.set_pin_pul_inner(pin, pull);
+            }
+            PinMode::Output => {
+                self.set_pin_cfg_inner(pin, 1); // TODO is it the same for all pins?
+                self.set_pin_pul_inner(pin, pull);
+            }
+            PinMode::InputInterrupt => {
+                todo!()
+            }
+            PinMode::Alt => {
+                assert!(cfg.func > 1 && cfg.func < 7);
+                self.set_pin_cfg_inner(pin, cfg.func);
+            }
+        }
+        Ok(())
+    }
+
+    unsafe fn get_pin_config(&mut self, _pin: u32) -> Result<PinConfig, Errno> {
+        todo!()
+    }
+
+    fn set_pin(&mut self, pin: u32) {
+        self.regs.DAT.set(self.regs.DAT.get() | (1 << pin));
+    }
+
+    fn clear_pin(&mut self, pin: u32) {
+        self.regs.DAT.set(self.regs.DAT.get() & !(1 << pin));
+    }
+
+    fn toggle_pin(&mut self, pin: u32) {
+        self.regs.DAT.set(self.regs.DAT.get() ^ (1 << pin));
+    }
+
+    fn read_pin(&mut self, pin: u32) -> Result<bool, Errno> {
+        Ok(self.regs.DAT.get() & (1 << pin) != 0)
+    }
+}
+
+impl Gpio {
+    #[inline]
+    fn set_pin_cfg_inner(&mut self, pin: u32, cfg: u32) {
+        let reg = pin >> 3;
+        let shift = (pin & 0x7) * 4;
+        let tmp = self.regs.CFG[reg as usize].get() & !(0xF << shift);
+        self.regs.CFG[reg as usize].set(tmp | ((cfg & 0x7) << shift));
+    }
+
+    #[inline]
+    fn set_pin_pul_inner(&mut self, pin: u32, pul: u32) {
+        let reg = pin >> 4;
+        let shift = (pin & 0xF) * 2;
+        let tmp = self.regs.PUL[reg as usize].get() & !(0x3 << shift);
+        self.regs.PUL[reg as usize].set(tmp | ((pul & 0x3) << shift));
+    }
+
+    pub const unsafe fn new(base: usize) -> Self {
+        Self {
+            regs: MemoryIo::new(base),
+        }
+    }
+}
diff --git a/kernel/src/arch/aarch64/mach_orangepi3/mod.rs b/kernel/src/arch/aarch64/mach_orangepi3/mod.rs
index 2ddb954..890523c 100644
--- a/kernel/src/arch/aarch64/mach_orangepi3/mod.rs
+++ b/kernel/src/arch/aarch64/mach_orangepi3/mod.rs
@@ -1,51 +1,35 @@
-//! QEMU virt machine
+//! Xunlong Orange Pi 3, with Allwinner H6 SoC
 
 use crate::arch::aarch64::timer::GenericTimer;
-use crate::dev::{Device, serial::SerialDevice};
-use crate::dev::timer::TimestampSource;
+use crate::dev::{
+    gpio::{GpioDevice, PinConfig},
+    serial::SerialDevice,
+    timer::TimestampSource,
+    Device,
+};
 use crate::sync::Spin;
 use error::Errno;
 
-fn delay(mut p: usize) {
-    while p != 0 {
-        cortex_a::asm::nop();
-        p -= 1;
-    }
-}
+mod gpio;
+mod uart;
 
-struct Uart {
-    base: usize
-}
+use gpio::Gpio;
+use uart::Uart;
 
-impl Device for Uart {
-    fn name() -> &'static str {
-        "Allwinner H6 UART"
-    }
+#[allow(missing_docs)]
+pub fn init_board() -> Result<(), Errno> {
+    unsafe {
+        let mut gpioh = GPIOH.lock();
+        gpioh.set_pin_config(0, &PinConfig::alt(gpio::PH0_UART0_TX))?;
+        gpioh.set_pin_config(1, &PinConfig::alt(gpio::PH1_UART0_RX))?;
 
-    unsafe fn enable(&mut self) -> Result<(), Errno> {
-        todo!()
-    }
-}
-
-impl SerialDevice for Uart {
-    fn send(&mut self, byte: u8) -> Result<(), Errno> {
-        unsafe {
-            if byte == b'\n' {
-                core::ptr::write_volatile(self.base as *mut u32, 13u32);
-                delay(10000);
-            }
-            core::ptr::write_volatile(self.base as *mut u32, byte as u32);
-            delay(10000);
-        }
-        Ok(())
-    }
-
-    fn recv(&mut self, blocking: bool) -> Result<u8, Errno> {
-        todo!()
+        UART0.lock().enable()?;
     }
+    Ok(())
 }
 
 const UART0_BASE: usize = 0x05000000;
+const PIO_BASE: usize = 0x0300B000;
 
 /// Returns primary console for this machine
 #[inline]
@@ -53,10 +37,14 @@ pub fn console() -> &'static Spin<impl SerialDevice> {
     &UART0
 }
 
-///// Returns the timer used as CPU-local periodic IRQ source
-//#[inline]
-//pub fn local_timer() -> &'static Spin<impl TimestampSource> {
-//    &LOCAL_TIMER
-//}
+/// Returns the timer used as CPU-local periodic IRQ source
+#[inline]
+pub fn local_timer() -> &'static Spin<impl TimestampSource> {
+    &LOCAL_TIMER
+}
 
-static UART0: Spin<Uart> = Spin::new(Uart { base: UART0_BASE });
+static UART0: Spin<Uart> = Spin::new(unsafe { Uart::new(UART0_BASE) });
+static LOCAL_TIMER: Spin<GenericTimer> = Spin::new(GenericTimer {});
+#[allow(dead_code)]
+static GPIOD: Spin<Gpio> = Spin::new(unsafe { Gpio::new(PIO_BASE + 0x24 * 3) });
+static GPIOH: Spin<Gpio> = Spin::new(unsafe { Gpio::new(PIO_BASE + 0x24 * 7) });
diff --git a/kernel/src/arch/aarch64/mach_orangepi3/uart.rs b/kernel/src/arch/aarch64/mach_orangepi3/uart.rs
new file mode 100644
index 0000000..3421f47
--- /dev/null
+++ b/kernel/src/arch/aarch64/mach_orangepi3/uart.rs
@@ -0,0 +1,106 @@
+use crate::arch::MemoryIo;
+use crate::dev::{serial::SerialDevice, Device};
+use error::Errno;
+use tock_registers::registers::{Aliased, ReadOnly, ReadWrite};
+use tock_registers::interfaces::{Readable, Writeable};
+use tock_registers::{register_bitfields, register_structs};
+
+register_bitfields! [
+    u32,
+    IER [
+        PTIME OFFSET(7) NUMBITS(1) [],
+        RS485_INT_EN OFFSET(4) NUMBITS(1) [],
+        EDSSI OFFSET(3) NUMBITS(1) [],
+        ELSI OFFSET(2) NUMBITS(1) [],
+        ETBEI OFFSET(1) NUMBITS(1) [],
+        ERBFI OFFSET(0) NUMBITS(1) [],
+    ],
+    IIR [
+        FEFLAG OFFSET(6) NUMBITS(2) [
+            Enable = 3,
+            Disable = 0
+        ],
+        IID OFFSET(0) NUMBITS(4) [
+            ModemStatus = 0,
+            NoInterrupt = 1,
+            ThrEmpty = 2,
+            Rs485Interrupt = 3,
+            ReceivedDataAvailable = 4,
+            ReceiverLineStatus = 6,
+            BusyDetect = 7,
+            CharacterTimeout = 12
+        ]
+    ],
+    LSR [
+        FIFOERR OFFSET(7) NUMBITS(1) [],
+        TEMT OFFSET(6) NUMBITS(1) [],
+        THRE OFFSET(5) NUMBITS(1) [],
+        BI OFFSET(4) NUMBITS(1) [],
+        FE OFFSET(3) NUMBITS(1) [],
+        PE OFFSET(2) NUMBITS(1) [],
+        OE OFFSET(1) NUMBITS(1) [],
+        DR OFFSET(0) NUMBITS(1) []
+    ]
+];
+
+register_structs! {
+    #[allow(non_snake_case)]
+    Regs {
+        (0x0000 => DR_DLL: Aliased<u32>),
+        (0x0004 => IER_DLH: ReadWrite<u32, IER::Register>),
+        (0x0008 => IIR_FCR: Aliased<u32, IIR::Register, ()>),
+        (0x000C => LCR: ReadWrite<u32>),
+        (0x0010 => MCR: ReadWrite<u32>),
+        (0x0014 => LSR: ReadOnly<u32, LSR::Register>),
+        (0x0018 => MSR: ReadOnly<u32>),
+        (0x001C => SCH: ReadWrite<u32>),
+        (0x0020 => _res0),
+        (0x007C => USR: ReadOnly<u32>),
+        (0x0080 => TFL: ReadWrite<u32>),
+        (0x0084 => RFL: ReadWrite<u32>),
+        (0x0088 => HSK: ReadWrite<u32>),
+        (0x008C => _res1),
+        (0x00A4 => HALT: ReadWrite<u32>),
+        (0x00D0 => @END),
+    }
+}
+
+pub(super) struct Uart {
+    regs: MemoryIo<Regs>,
+}
+
+impl Device for Uart {
+    fn name() -> &'static str {
+        "Allwinner H6 UART"
+    }
+
+    unsafe fn enable(&mut self) -> Result<(), Errno> {
+        // TODO
+        Ok(())
+    }
+}
+
+impl SerialDevice for Uart {
+    fn send(&mut self, byte: u8) -> Result<(), Errno> {
+        while !self.regs.LSR.matches_all(LSR::THRE::SET) {
+            cortex_a::asm::nop();
+        }
+        self.regs.DR_DLL.set(byte as u32);
+        Ok(())
+    }
+
+    fn recv(&mut self, _blocking: bool) -> Result<u8, Errno> {
+        while !self.regs.LSR.matches_all(LSR::DR::SET) {
+            cortex_a::asm::nop();
+        }
+        Ok(self.regs.DR_DLL.get() as u8)
+    }
+}
+
+impl Uart {
+    pub const unsafe fn new(base: usize) -> Self {
+        Self {
+            regs: MemoryIo::new(base),
+        }
+    }
+}
diff --git a/kernel/src/arch/aarch64/mach_qemu/mod.rs b/kernel/src/arch/aarch64/mach_qemu/mod.rs
index b95de4a..5c4d38a 100644
--- a/kernel/src/arch/aarch64/mach_qemu/mod.rs
+++ b/kernel/src/arch/aarch64/mach_qemu/mod.rs
@@ -1,12 +1,21 @@
 //! QEMU virt machine
 
 use crate::arch::aarch64::timer::GenericTimer;
-use crate::dev::serial::{pl011::Pl011, SerialDevice};
+use crate::dev::{Device, serial::{pl011::Pl011, SerialDevice}};
 use crate::dev::timer::TimestampSource;
 use crate::sync::Spin;
+use error::Errno;
 
 const UART0_BASE: usize = 0x09000000;
 
+#[allow(missing_docs)]
+pub fn init_board() -> Result<(), Errno> {
+    unsafe {
+        UART0.lock().enable()?;
+    }
+    Ok(())
+}
+
 /// Returns primary console for this machine
 #[inline]
 pub fn console() -> &'static Spin<impl SerialDevice> {
diff --git a/kernel/src/arch/aarch64/vectors.S b/kernel/src/arch/aarch64/vectors.S
index 958a621..1b7e2d6 100644
--- a/kernel/src/arch/aarch64/vectors.S
+++ b/kernel/src/arch/aarch64/vectors.S
@@ -1,6 +1,6 @@
 .section .text
 .global aa64_el1_vectors
-.p2align 8
+.p2align 12
 aa64_el1_vectors:
 .el1_sp_el0_sync:
     b .
diff --git a/kernel/src/debug.rs b/kernel/src/debug.rs
index a7d969d..e521fbe 100644
--- a/kernel/src/debug.rs
+++ b/kernel/src/debug.rs
@@ -15,6 +15,9 @@ impl<T: SerialDevice> fmt::Write for SerialOutput<T> {
     fn write_str(&mut self, s: &str) -> fmt::Result {
         let mut lock = self.inner.lock();
         for &byte in s.as_bytes() {
+            if byte == b'\n' {
+                lock.send(b'\r').ok();
+            }
             // TODO check for errors
             lock.send(byte).ok();
         }
diff --git a/kernel/src/dev/gpio.rs b/kernel/src/dev/gpio.rs
new file mode 100644
index 0000000..0dd649e
--- /dev/null
+++ b/kernel/src/dev/gpio.rs
@@ -0,0 +1,76 @@
+//! GPIO and pin control interfaces
+
+use crate::dev::Device;
+use error::Errno;
+
+/// Pin function mode
+pub enum PinMode {
+    /// Do not use pin
+    Disable = 0,
+    /// Use pin as a GPIO input
+    Input,
+    /// Use pin as a GPIO output
+    Output,
+    /// Use pin as an external interrupt trigger source
+    InputInterrupt,
+    /// Use pin for peripheral functionality
+    Alt,
+}
+
+/// Input/output pin pull mode
+pub enum PullMode {
+    /// No pull
+    None,
+    /// Pull up
+    Up,
+    /// Pull down
+    Down,
+}
+
+/// Pin configuration for [GpioDevice::set_pin_config]
+pub struct PinConfig {
+    /// Pin function
+    pub mode: PinMode,
+    /// Pin pull mode, only used for Input/Output pins
+    pub pull: PullMode,
+    /// Alternate pin function, only used when mode == [PinMode::Alt]
+    pub func: u32,
+}
+
+// TODO separate traits for "single port controller" and "global gpio controller"
+/// Generic GPIO controller interface
+pub trait GpioDevice: Device {
+    /// Initializes configuration for given pin
+    unsafe fn set_pin_config(&mut self, pin: u32, cfg: &PinConfig) -> Result<(), Errno>;
+    /// Returns current configuration of given pin
+    unsafe fn get_pin_config(&mut self, pin: u32) -> Result<PinConfig, Errno>;
+
+    /// Sets `pin` to HIGH state
+    fn set_pin(&mut self, pin: u32);
+    /// Sets `pin` to LOW state
+    fn clear_pin(&mut self, pin: u32);
+    /// Toggles `pin`'s HIGH/LOW state
+    fn toggle_pin(&mut self, pin: u32);
+    /// Returns `true` if input `pin` is in HIGH state
+    fn read_pin(&mut self, pin: u32) -> Result<bool, Errno>;
+}
+
+impl PinConfig {
+    /// Alternative (peripheral) pin configuration
+    pub const fn alt(func: u32) -> Self {
+        Self {
+            mode: PinMode::Alt,
+            pull: PullMode::None,
+            func
+        }
+    }
+
+    /// Pull-down output
+    pub const fn out_pull_down() -> Self {
+        Self {
+            mode: PinMode::Output,
+            pull: PullMode::Down,
+            func: 0
+        }
+    }
+}
diff --git a/kernel/src/dev/mod.rs b/kernel/src/dev/mod.rs
index 5e17083..ba0d874 100644
--- a/kernel/src/dev/mod.rs
+++ b/kernel/src/dev/mod.rs
@@ -5,6 +5,7 @@ use error::Errno;
 // Device classes
 pub mod serial;
 pub mod timer;
+pub mod gpio;
 
 /// Generic device trait
 pub trait Device {