TcpStream.recv(): wrap callback in RefCell to allow FnMut

2020-07-23 18:58:25 +02:00
33 changed files with 501 additions and 1584 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -98,13 +98,13 @@ dependencies = [
 "libboard_zynq 0.0.0",
 "libcortex_a9 0.0.0",
 "libregister 0.0.0",
- "linked_list_allocator 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "linked_list_allocator 0.8.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "r0 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
 name = "linked_list_allocator"
-version = "0.8.4"
+version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"

 [[package]]
@ -170,7 +170,7 @@ dependencies = [
 "checksum cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 "checksum compiler_builtins 0.1.27 (registry+https://github.com/rust-lang/crates.io-index)" = "38f18416546abfbf8d801c555a0e99524453e7214f9cc9107ad49de3d5948ccc"
 "checksum embedded-hal 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ee4908a155094da7723c2d60d617b820061e3b4efcc3d9e293d206a5a76c170b"
-"checksum linked_list_allocator 0.8.4 (registry+https://github.com/rust-lang/crates.io-index)" = "e70e46c13c0e8374c26cec5752e3347ca1087d9711de8f45aa513a7700efd73d"
+"checksum linked_list_allocator 0.8.3 (registry+https://github.com/rust-lang/crates.io-index)" = "d6b60501dd4c850950bb43f970d544f6ce04e0ca021da2db2538fbe9d923f19e"
 "checksum log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)" = "14b6052be84e6b71ab17edffc2eeabf5c2c3ae1fdb464aae35ac50c67a44e1f7"
 "checksum managed 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "fdcec5e97041c7f0f1c5b7d93f12e57293c831c646f4cc7a5db59460c7ea8de6"
 "checksum nb 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b1411551beb3c11dedfb0a90a0fa256b47d28b9ec2cdff34c25a2fa59e45dbdc"
--- a/README.md
+++ b/README.md
@ -1,7 +1,7 @@
 # Build

 ```shell
-nix-shell --command "cargo xbuild --release -p experiments"
+nix-shell --command "cargo xbuild --release"
 ```

 Currently the ELF output is placed at `target/armv7-none-eabihf/release/experiments`
@ -41,7 +41,7 @@ Proceed using gdb with `load`, `c`
 ### Running on the ZC706

 ```shell
-nix-shell --command "cargo xbuild --release -p experiments"
+nix-shell --command "cargo xbuild --release"
 cd openocd
 openocd -f zc706.cfg
 ```
@ -64,19 +64,16 @@ openocd -f zc706.cfg -c "pld load 0 blinker_migen.bit; exit"

 Clone this repo onto your development/build machine and the raspberry pi that controls the Xilinx 7000 board

-On the dev machine, the below script builds zc706 and secure copies it to the target pi (in your pi $HOME directory):
+On the dev machine, the below script builds zc706 and secure copies it to the target pi (in your pi $HOME directory)
 ```shell
-cd ~/zynq-rs
-./build.sh $your_user_or_ssh_id
+cd ~/zc706
+./build.sh $your_user/ssh_id
 ```

 On the pi, we need an information rich environment that includes a relatively reliable `gdb` experience (that includes `ctrl-p` and `ctrl-n` command history that persists across `cgdb` executions), run:
 ```shell
 ssh pi4
-cd zynq-rs
-# For ZC706, run:
-./tmux.sh 0
-# For Cora Z7, run:
+cd zc706
 ./tmux.sh
 ```

--- a/build.sh
+++ b/build.sh
@ -1 +1 @@
-nix-shell --command "cargo xbuild --release -p experiments" && scp -C target/armv7-none-eabihf/release/experiments $1@rpi-4.m-labs.hk:/home/$1/zc706/zc706.elf
+nix-shell --command "cargo xbuild --release" && scp -P 2204 -C target/armv7-none-eabihf/release/zc706-experiments $1@nixbld.m-labs.hk:/home/$1/zc706/zc706.elf
--- a/default.nix
+++ b/default.nix
@ -49,7 +49,7 @@ let
    name = "${crate}";
    src = ./.;
    crateSubdir = crate;
-    cargoSha256 = "1c1qpg9by8bg93yhgllb5xs155g27qmh99pbrb681wazm8k7nwim";
+    cargoSha256 = "0xlynsr94dyv0g41qwk5490w3wnzd5g70msaih6mcbgr3v4s2q34";
    cargoFeatures = features;
    doCheck = false;
    dontFixup = true;
--- a/experiments/Cargo.toml
+++ b/experiments/Cargo.toml
@ -16,5 +16,5 @@ embedded-hal = "0.2"
 libregister = { path = "../libregister" }
 libcortex_a9 = { path = "../libcortex_a9" }
 libboard_zynq = { path = "../libboard_zynq" }
-libsupport_zynq = { path = "../libsupport_zynq", default-features = false, features = ["panic_handler"]}
+libsupport_zynq = { path = "../libsupport_zynq" }
 libasync = { path = "../libasync" }
--- a/experiments/link.x
+++ b/experiments/link.x
@ -44,10 +44,6 @@ SECTIONS
        __stack0_end = .;
        . = ORIGIN(OCM3) + LENGTH(OCM3) - 8;
        __stack0_start = .;
-
-        /* unused heap0 to prevent the linker from complaining*/
-        __heap0_start = .;
-        __heap0_end = .;
    } > OCM3

    /DISCARD/ :
--- a/experiments/src/main.rs
+++ b/experiments/src/main.rs
@ -1,7 +1,5 @@
 #![no_std]
 #![no_main]
-#![feature(const_in_array_repeat_expressions)]
-#![feature(naked_functions)]

 extern crate alloc;

@ -15,9 +13,8 @@ use libboard_zynq::{
    self as zynq,
    clocks::source::{ArmPll, ClockSource, IoPll},
    clocks::Clocks,
-    print, println, stdio,
-    mpcore,
-    gic,
+    print, println,
+    sdio::sd_card::SdCard,
    smoltcp::{
        iface::{EthernetInterfaceBuilder, NeighborCache, Routes},
        time::Instant,
@ -25,70 +22,24 @@ use libboard_zynq::{
    },
    time::Milliseconds,
 };
+#[cfg(feature = "target_zc706")]
+use libboard_zynq::ps7_init;
 use libcortex_a9::{
    mutex::Mutex,
-    sync_channel::{Sender, Receiver},
-    sync_channel,
-    regs::{MPIDR, SP},
-    spin_lock_yield, notify_spin_lock,
-    asm
+    sync_channel::{self, sync_channel},
 };
-use libregister::{RegisterR, RegisterW};
+use libregister::RegisterR;
 use libsupport_zynq::{
    boot, ram,
 };
 use log::{info, warn};
-use core::sync::atomic::{AtomicBool, Ordering};

 const HWADDR: [u8; 6] = [0, 0x23, 0xde, 0xea, 0xbe, 0xef];

-static mut CORE1_REQ: (Sender<usize>, Receiver<usize>) = sync_channel!(usize, 10);
-static mut CORE1_RES: (Sender<usize>, Receiver<usize>) = sync_channel!(usize, 10);
-
-extern "C" {
-    static mut __stack1_start: u32;
-}
-
-static CORE1_RESTART: AtomicBool = AtomicBool::new(false);
-
-#[link_section = ".text.boot"]
-#[no_mangle]
-#[naked]
-pub unsafe extern "C" fn IRQ() {
-    if MPIDR.read().cpu_id() == 1{
-        let mpcore = mpcore::RegisterBlock::new();
-        let mut gic = gic::InterruptController::new(mpcore);
-        let id = gic.get_interrupt_id();
-        if id.0 == 0 {
-            gic.end_interrupt(id);
-            asm::exit_irq();
-            SP.write(&mut __stack1_start as *mut _ as u32);
-            asm::enable_irq();
-            CORE1_RESTART.store(false, Ordering::Relaxed);
-            notify_spin_lock();
-            main_core1();
-        }
-    }
-    stdio::drop_uart();
-    println!("IRQ");
-    loop {}
-}
-
-pub fn restart_core1() {
-    let mut interrupt_controller = gic::InterruptController::new(mpcore::RegisterBlock::new());
-    CORE1_RESTART.store(true, Ordering::Relaxed);
-    interrupt_controller.send_sgi(gic::InterruptId(0), gic::CPUCore::Core1.into());
-    while CORE1_RESTART.load(Ordering::Relaxed) {
-        spin_lock_yield();
-    }
-}
-
 #[no_mangle]
 pub fn main_core0() {
    // zynq::clocks::CpuClocks::enable_io(1_250_000_000);
    println!("\nzc706 main");
-    let mut interrupt_controller = gic::InterruptController::new(mpcore::RegisterBlock::new());
-    interrupt_controller.enable_interrupts();
    // ps7_init::apply();
    libboard_zynq::stdio::drop_uart();

@ -131,6 +82,25 @@ pub fn main_core0() {
        clocks.cpu_1x()
    );

+    let sd = libboard_zynq::sdio::SDIO::sdio0(true);
+    // only test SD card if it is inserted
+    if sd.is_card_inserted() {
+        let result = SdCard::from_sdio(sd);
+        match &result {
+            Ok(_) => info!("OK!"),
+            Err(a) => info!("{}", a),
+        };
+        const SIZE: usize = 512 * 2 + 1;
+        let mut sd_card = result.unwrap();
+        if false {
+            let buffer: [u8; SIZE] = [5; SIZE];
+            sd_card.write_block(0x0, 2, &buffer).unwrap();
+        }
+        let mut buffer: [u8; SIZE] = [0; SIZE];
+        sd_card.read_block(0 /*0x1*/, 2, &mut buffer[1..]).unwrap();
+        info!("buffer = {:?}", &buffer[..]);
+    }
+
    let mut flash = zynq::flash::Flash::new(200_000_000).linear_addressing_mode();
    let flash_ram: &[u8] = unsafe { core::slice::from_raw_parts(flash.ptr(), flash.size()) };
    for i in 0..=1 {
@ -188,54 +158,20 @@ pub fn main_core0() {
        flash = flash_io.stop();
    }

-    boot::Core1::start(false);
+    let core1 = boot::Core1::start(false);

-    let core1_req = unsafe { &mut CORE1_REQ.0 };
-    let core1_res = unsafe { &mut CORE1_RES.1 };
+    let (mut core1_req, rx) = sync_channel(10);
+    *CORE1_REQ.lock() = Some(rx);
+    let (tx, mut core1_res) = sync_channel(10);
+    *CORE1_RES.lock() = Some(tx);
    task::block_on(async {
        for i in 0..10 {
-            restart_core1();
            core1_req.async_send(i).await;
            let j = core1_res.async_recv().await;
            println!("{} -> {}", i, j);
        }
    });
-    unsafe {
-        core1_req.drop_elements();
-    }
-    
-    // Test I2C
-    #[cfg(feature = "target_zc706")]
-    {
-        let mut i2c = zynq::i2c::I2C::i2c();
-        i2c.init();
-        println!("I2C bit-banging enabled");
-        let mut eeprom = zynq::i2c::eeprom::EEPROM::new(&mut i2c, 16);
-        // Write to 0x00 and 0x08
-        let eeprom_buffer: [u8; 22] = [
-            0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 
-            0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 
-            0xef, 0xcd, 0xab, 0x89, 0x67, 0x45, 0x23, 0x01,
-        ];
-        eeprom.write(0x00, &eeprom_buffer[0..6]);
-        eeprom.write(0x08, &eeprom_buffer[6..22]);
-        println!("Data written to EEPROM");
-        let mut eeprom_buffer = [0u8; 24];
-        // Read from 0x00
-        eeprom.read(0x00, &mut eeprom_buffer);
-        print!("Data read from EEPROM @ 0x00: (hex) ");
-        for i in 0..6 {
-            print!("{:02x} ", eeprom_buffer[i]);
-        }
-        println!("");
-        // Read from 0x08
-        eeprom.read(0x08, &mut eeprom_buffer);
-        print!("Data read from EEPROM @ 0x08: (hex) ");
-        for i in 0..16 {
-            print!("{:02x} ", eeprom_buffer[i]);
-        }
-        println!("");
-    }
+    core1.disable();

    let eth = zynq::eth::Eth::default(HWADDR.clone());
    println!("Eth on");
@ -260,6 +196,9 @@ pub fn main_core0() {
        .neighbor_cache(neighbor_cache)
        .finalize();

+    #[cfg(feature = "target_zc706")]
+    ps7_init::report_differences();
+
    Sockets::init(32);

    const TCP_PORT: u16 = 19;
@ -326,18 +265,27 @@ pub fn main_core0() {
    })
 }

+static CORE1_REQ: Mutex<Option<sync_channel::Receiver<usize>>> = Mutex::new(None);
+static CORE1_RES: Mutex<Option<sync_channel::Sender<usize>>> = Mutex::new(None);
 static DONE: Mutex<bool> = Mutex::new(false);

 #[no_mangle]
 pub fn main_core1() {
    println!("Hello from core1!");
-    let mut interrupt_controller = gic::InterruptController::new(mpcore::RegisterBlock::new());
-    interrupt_controller.enable_interrupts();
-    let req = unsafe { &mut CORE1_REQ.1 };
-    let res = unsafe { &mut CORE1_RES.0 };
+
+    let mut req = None;
+    while req.is_none() {
+        req = CORE1_REQ.lock().take();
+    }
+    let req = req.unwrap();
+    let mut res = None;
+    while res.is_none() {
+        res = CORE1_RES.lock().take();
+    }
+    let mut res = res.unwrap();

    for i in req {
-        res.send(i * i);
+        res.send(*i * *i);
    }

    println!("core1 done!");
--- a/libasync/src/smoltcp/tcp_stream.rs
+++ b/libasync/src/smoltcp/tcp_stream.rs
@ -3,7 +3,9 @@
 //! TODO: implement futures AsyncRead/AsyncWrite/Stream/Sink interfaces

 use core::{
+    cell::RefCell,
    future::Future,
+    ops::DerefMut,
    pin::Pin,
    task::{Context, Poll},
 };
@ -108,17 +110,18 @@ impl TcpStream {
    /// number of bytes it consumed, and a user-defined return value of type R.
    pub async fn recv<F, R>(&self, f: F) -> Result<R>
    where
-        F: Fn(&[u8]) -> (usize, R),
+        F: FnMut(&[u8]) -> (usize, R),
    {
-        struct Recv<'a, F: FnOnce(&[u8]) -> (usize, R), R> {
+        struct Recv<'a, F: FnMut(&[u8]) -> (usize, R), R> {
            stream: &'a TcpStream,
-            f: F,
+            f: RefCell<F>,
        }

-        impl<'a, F: Fn(&[u8]) -> (usize, R), R> Future for Recv<'a, F, R> {
+        impl<'a, F: FnMut(&[u8]) -> (usize, R), R> Future for Recv<'a, F, R> {
            type Output = Result<R>;

            fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+                let mut f = self.f.borrow_mut();
                let result = self.stream.with_socket(|mut socket| {
                    if socket_is_handhshaking(&socket) {
                        return Ok(Poll::Pending);
@ -126,7 +129,7 @@ impl TcpStream {

                    socket.recv(|buf| {
                        if buf.len() > 0 {
-                            let (amount, result) = (self.f)(buf);
+                            let (amount, result) = (f.deref_mut())(buf);
                            assert!(amount > 0);
                            (amount, Poll::Ready(Ok(result)))
                        } else {
@ -150,7 +153,7 @@ impl TcpStream {

        Recv {
            stream: self,
-            f,
+            f: RefCell::new(f),
        }.await
    }

--- a/libboard_zynq/src/ddr/mod.rs
+++ b/libboard_zynq/src/ddr/mod.rs
@ -56,35 +56,14 @@ impl DdrRam {
        clocks
    }

-    fn calculate_dci_divisors(clocks: &Clocks) -> (u8, u8) {
-        let target = (DCI_FREQ - 1 + clocks.ddr) / DCI_FREQ;
-
-        let mut best = None;
-        let mut best_error = 0;
-        for divisor0 in 1..63 {
-            for divisor1 in 1..63 {
-                let current = (divisor0 as u32) * (divisor1 as u32);
-                let error = if current > target {
-                    current - target
-                } else {
-                    target - current
-                };
-                if best.is_none() || best_error > error {
-                    best = Some((divisor0, divisor1));
-                    best_error = error;
-                }
-            }
-        }
-        best.unwrap()
-    }
-
    /// Zynq-7000 AP SoC Technical Reference Manual:
    /// 10.6.2 DDR IOB Impedance Calibration
    fn calibrate_iob_impedance(clocks: &Clocks) {
-        let (divisor0, divisor1) = Self::calculate_dci_divisors(clocks);
-        debug!("DDR DCI clock: {} Hz (divisors={}*{})",
-               clocks.ddr / u32::from(divisor0) / u32::from(divisor1),
-               divisor0, divisor1);
+        let divisor0 = ((DCI_FREQ - 1 + clocks.ddr) / DCI_FREQ)
+            .max(1).min(63) as u8;
+        let divisor1 = ((DCI_FREQ - 1 + clocks.ddr) / DCI_FREQ / u32::from(divisor0))
+            .max(1).min(63) as u8;
+        debug!("DDR DCI clock: {} Hz", clocks.ddr / u32::from(divisor0) / u32::from(divisor1));

        slcr::RegisterBlock::unlocked(|slcr| {
            // Step 1.
--- a/libboard_zynq/src/eth/mod.rs
+++ b/libboard_zynq/src/eth/mod.rs
@ -1,8 +1,5 @@
-use core::{
-    marker::PhantomData,
-    ops::{Deref, DerefMut},
-};
-use log::{debug, info, warn, error};
+use core::ops::{Deref, DerefMut};
+use log::{error, info, warn};
 use libregister::*;
 use super::slcr;
 use super::clocks::Clocks;
@ -45,109 +42,14 @@ impl DerefMut for Buffer {
    }
 }

-/// Gigabit Ethernet Peripheral
-pub trait Gem {
-    fn setup_clock(tx_clock: u32);
-    fn regs() -> &'static mut regs::RegisterBlock;
-}
-
-/// first Gigabit Ethernet peripheral
-pub struct Gem0;
-
-impl Gem for Gem0 {
-    fn setup_clock(tx_clock: u32) {
-        let (divisor0, divisor1) = calculate_tx_divisors(tx_clock);
-
-        slcr::RegisterBlock::unlocked(|slcr| {
-            slcr.gem0_clk_ctrl.write(
-                // 0x0050_0801: 8, 5: 100 Mb/s
-                // ...: 8, 1: 1000 Mb/s
-                slcr::GemClkCtrl::zeroed()
-                    .clkact(true)
-                    .srcsel(slcr::PllSource::IoPll)
-                    .divisor(divisor0 as u8)
-                    .divisor1(divisor1 as u8)
-            );
-            // Enable gem0 recv clock
-            slcr.gem0_rclk_ctrl.write(
-                // 0x0000_0801
-                slcr::RclkCtrl::zeroed()
-                    .clkact(true)
-            );
-        });
-    }
-
-    fn regs() -> &'static mut regs::RegisterBlock {
-        regs::RegisterBlock::gem0()
-    }
-}
-
-/// second Gigabit Ethernet peripheal
-pub struct Gem1;
-
-impl Gem for Gem1 {
-    fn setup_clock(tx_clock: u32) {
-        let (divisor0, divisor1) = calculate_tx_divisors(tx_clock);
-
-        slcr::RegisterBlock::unlocked(|slcr| {
-            slcr.gem1_clk_ctrl.write(
-                slcr::GemClkCtrl::zeroed()
-                    .clkact(true)
-                    .srcsel(slcr::PllSource::IoPll)
-                    .divisor(divisor0 as u8)
-                    .divisor1(divisor1 as u8)
-            );
-            // Enable gem1 recv clock
-            slcr.gem1_rclk_ctrl.write(
-                // 0x0000_0801
-                slcr::RclkCtrl::zeroed()
-                    .clkact(true)
-            );
-        });
-    }
-
-    fn regs() -> &'static mut regs::RegisterBlock {
-        regs::RegisterBlock::gem1()
-    }
-}
-
-fn calculate_tx_divisors(tx_clock: u32) -> (u8, u8) {
-    let io_pll = Clocks::get().io;
-    let target = (tx_clock - 1 + io_pll) / tx_clock;
-
-    let mut best = None;
-    let mut best_error = 0;
-    for divisor0 in 1..63 {
-        for divisor1 in 1..63 {
-            let current = (divisor0 as u32) * (divisor1 as u32);
-            let error = if current > target {
-                current - target
-            } else {
-                target - current
-            };
-            if best.is_none() || best_error > error {
-                best = Some((divisor0, divisor1));
-                best_error = error;
-            }
-        }
-    }
-    let result = best.unwrap();
-    debug!("Eth TX clock for {}: {} / {} / {} = {}",
-           tx_clock, io_pll,
-           result.0, result.1,
-           io_pll / result.0 as u32 / result.1 as u32
-    );
-    result
-}
-
-pub struct Eth<GEM: Gem, RX, TX> {
+pub struct Eth<'r, RX, TX> {
    rx: RX,
    tx: TX,
-    inner: EthInner<GEM>,
+    inner: EthInner<'r>,
    phy: Phy,
 }

-impl Eth<Gem0, (), ()> {
+impl<'r> Eth<'r, (), ()> {
    pub fn default(macaddr: [u8; 6]) -> Self {
        slcr::RegisterBlock::unlocked(|slcr| {
            // Manual example: 0x0000_1280
@ -280,23 +182,22 @@ impl Eth<Gem0, (), ()> {
    }

    pub fn gem0(macaddr: [u8; 6]) -> Self {
-        Self::new(macaddr)
-    }
+        Self::setup_gem0_clock(TX_1000);
+
+        let regs = regs::RegisterBlock::gem0();
+        Self::from_regs(regs, macaddr)
    }

-
-impl Eth<Gem1, (), ()> {
    pub fn gem1(macaddr: [u8; 6]) -> Self {
-        Self::new(macaddr)
-    }
+        Self::setup_gem1_clock(TX_1000);
+
+        let regs = regs::RegisterBlock::gem1();
+        Self::from_regs(regs, macaddr)
    }

-impl<GEM: Gem> Eth<GEM, (), ()> {
-    fn new(macaddr: [u8; 6]) -> Self {
-        GEM::setup_clock(TX_1000);
-
+    fn from_regs(regs: &'r mut regs::RegisterBlock, macaddr: [u8; 6]) -> Self {
        let mut inner = EthInner {
-            gem: PhantomData,
+            regs,
            link: None,
        };
        inner.init();
@ -315,8 +216,54 @@ impl<GEM: Gem> Eth<GEM, (), ()> {
    }
 }

-impl<GEM: Gem, RX, TX> Eth<GEM, RX, TX> {
-    pub fn start_rx(self, rx_size: usize) -> Eth<GEM, rx::DescList, TX> {
+impl<'r, RX, TX> Eth<'r, RX, TX> {
+    pub fn setup_gem0_clock(tx_clock: u32) {
+        let io_pll = Clocks::get().io;
+        let d0 = ((tx_clock - 1 + io_pll) / tx_clock).max(1).min(63);
+        let d1 = (io_pll / tx_clock / d0).max(1).min(63);
+
+        slcr::RegisterBlock::unlocked(|slcr| {
+            slcr.gem0_clk_ctrl.write(
+                // 0x0050_0801: 8, 5: 100 Mb/s
+                // ...: 8, 1: 1000 Mb/s
+                slcr::GemClkCtrl::zeroed()
+                    .clkact(true)
+                    .srcsel(slcr::PllSource::IoPll)
+                    .divisor(d0 as u8)
+                    .divisor1(d1 as u8)
+            );
+            // Enable gem0 recv clock
+            slcr.gem0_rclk_ctrl.write(
+                // 0x0000_0801
+                slcr::RclkCtrl::zeroed()
+                    .clkact(true)
+            );
+        });
+    }
+
+    pub fn setup_gem1_clock(tx_clock: u32) {
+        let io_pll = Clocks::get().io;
+        let d0 = ((tx_clock - 1 + io_pll) / tx_clock).max(1).min(63);
+        let d1 = (io_pll / tx_clock / d0).max(1).min(63);
+
+        slcr::RegisterBlock::unlocked(|slcr| {
+            slcr.gem1_clk_ctrl.write(
+                slcr::GemClkCtrl::zeroed()
+                    .clkact(true)
+                    .srcsel(slcr::PllSource::IoPll)
+                    .divisor(d0 as u8)
+                    .divisor1(d1 as u8)
+            );
+            // Enable gem1 recv clock
+            slcr.gem1_rclk_ctrl.write(
+                // 0x0000_0801
+                slcr::RclkCtrl::zeroed()
+                    .clkact(true)
+            );
+        });
+    }
+
+    pub fn start_rx(self, rx_size: usize) -> Eth<'r, rx::DescList, TX> {
        let new_self = Eth {
            rx: rx::DescList::new(rx_size),
            tx: self.tx,
@ -325,17 +272,17 @@ impl<GEM: Gem, RX, TX> Eth<GEM, RX, TX> {
        };
        let list_addr = new_self.rx.list_addr();
        assert!(list_addr & 0b11 == 0);
-        GEM::regs().rx_qbar.write(
+        new_self.inner.regs.rx_qbar.write(
            regs::RxQbar::zeroed()
                .rx_q_baseaddr(list_addr >> 2)
        );
-        GEM::regs().net_ctrl.modify(|_, w|
+        new_self.inner.regs.net_ctrl.modify(|_, w|
            w.rx_en(true)
        );
        new_self
    }

-    pub fn start_tx(self, tx_size: usize) -> Eth<GEM, RX, tx::DescList> {
+    pub fn start_tx(self, tx_size: usize) -> Eth<'r, RX, tx::DescList> {
        let new_self = Eth {
            rx: self.rx,
            tx: tx::DescList::new(tx_size),
@ -344,23 +291,23 @@ impl<GEM: Gem, RX, TX> Eth<GEM, RX, TX> {
        };
        let list_addr = &new_self.tx.list_addr();
        assert!(list_addr & 0b11 == 0);
-        GEM::regs().tx_qbar.write(
+        new_self.inner.regs.tx_qbar.write(
            regs::TxQbar::zeroed()
                .tx_q_baseaddr(list_addr >> 2)
        );
-        GEM::regs().net_ctrl.modify(|_, w|
+        new_self.inner.regs.net_ctrl.modify(|_, w|
            w.tx_en(true)
        );
        new_self
    }
 }

-impl<GEM: Gem, TX> Eth<GEM, rx::DescList, TX> {
+impl<'r, TX> Eth<'r, rx::DescList, TX> {
    pub fn recv_next<'s: 'p, 'p>(&'s mut self) -> Result<Option<rx::PktRef<'p>>, rx::Error> {
-        let status = GEM::regs().rx_status.read();
+        let status = self.inner.regs.rx_status.read();
        if status.hresp_not_ok() {
            // Clear
-            GEM::regs().rx_status.write(
+            self.inner.regs.rx_status.write(
                regs::RxStatus::zeroed()
                    .hresp_not_ok(true)
            );
@ -368,7 +315,7 @@ impl<GEM: Gem, TX> Eth<GEM, rx::DescList, TX> {
        }
        if status.rx_overrun() {
            // Clear
-            GEM::regs().rx_status.write(
+            self.inner.regs.rx_status.write(
                regs::RxStatus::zeroed()
                    .rx_overrun(true)
            );
@ -376,7 +323,7 @@ impl<GEM: Gem, TX> Eth<GEM, rx::DescList, TX> {
        }
        if status.buffer_not_avail() {
            // Clear
-            GEM::regs().rx_status.write(
+            self.inner.regs.rx_status.write(
                regs::RxStatus::zeroed()
                    .buffer_not_avail(true)
            );
@ -388,7 +335,7 @@ impl<GEM: Gem, TX> Eth<GEM, rx::DescList, TX> {
            match result {
                Ok(None) => {
                    // No packet, clear status bit
-                    GEM::regs().rx_status.write(
+                    self.inner.regs.rx_status.write(
                        regs::RxStatus::zeroed()
                            .frame_recd(true)
                    );
@ -403,13 +350,13 @@ impl<GEM: Gem, TX> Eth<GEM, rx::DescList, TX> {
    }
 }

-impl<GEM: Gem, RX> Eth<GEM, RX, tx::DescList> {
+impl<'r, RX> Eth<'r, RX, tx::DescList> {
    pub fn send<'s: 'p, 'p>(&'s mut self, length: usize) -> Option<tx::PktRef<'p>> {
-        self.tx.send(GEM::regs(), length)
+        self.tx.send(self.inner.regs, length)
    }
 }

-impl<'a, GEM: Gem> smoltcp::phy::Device<'a> for &mut Eth<GEM, rx::DescList, tx::DescList> {
+impl<'r, 'a> smoltcp::phy::Device<'a> for &mut Eth<'r, rx::DescList, tx::DescList> {
    type RxToken = rx::PktRef<'a>;
    type TxToken = tx::Token<'a>;

@ -433,7 +380,7 @@ impl<'a, GEM: Gem> smoltcp::phy::Device<'a> for &mut Eth<GEM, rx::DescList, tx::
        match self.rx.recv_next() {
            Ok(Some(pktref)) => {
                let tx_token = tx::Token {
-                    regs: GEM::regs(),
+                    regs: self.inner.regs,
                    desc_list: &mut self.tx,
                };
                Some((pktref, tx_token))
@ -451,32 +398,33 @@ impl<'a, GEM: Gem> smoltcp::phy::Device<'a> for &mut Eth<GEM, rx::DescList, tx::

    fn transmit(&'a mut self) -> Option<Self::TxToken> {
        Some(tx::Token {
-            regs: GEM::regs(),
+            regs: self.inner.regs,
            desc_list: &mut self.tx,
        })
    }
+
 }


-struct EthInner<GEM: Gem> {
-    gem: PhantomData<GEM>,
+struct EthInner<'r> {
+    regs: &'r mut regs::RegisterBlock,
    link: Option<phy::Link>,
 }

-impl<GEM: Gem> EthInner<GEM> {
+impl<'r> EthInner<'r> {
    fn init(&mut self) {
        // Clear the Network Control register.
-        GEM::regs().net_ctrl.write(regs::NetCtrl::zeroed());
-        GEM::regs().net_ctrl.write(regs::NetCtrl::zeroed().clear_stat_regs(true));
+        self.regs.net_ctrl.write(regs::NetCtrl::zeroed());
+        self.regs.net_ctrl.write(regs::NetCtrl::zeroed().clear_stat_regs(true));
        // Clear the Status registers.
-        GEM::regs().rx_status.write(
+        self.regs.rx_status.write(
            regs::RxStatus::zeroed()
                .buffer_not_avail(true)
                .frame_recd(true)
                .rx_overrun(true)
                .hresp_not_ok(true)
        );
-        GEM::regs().tx_status.write(
+        self.regs.tx_status.write(
            regs::TxStatus::zeroed()
                .used_bit_read(true)
                .collision(true)
@ -490,7 +438,7 @@ impl<GEM: Gem> EthInner<GEM> {
                .hresp_not_ok(true)
        );
        // Disable all interrupts.
-        GEM::regs().intr_dis.write(
+        self.regs.intr_dis.write(
            regs::IntrDis::zeroed()
                .mgmt_done(true)
                .rx_complete(true)
@ -520,10 +468,10 @@ impl<GEM: Gem> EthInner<GEM> {
                .tsu_sec_incr(true)
        );
        // Clear the buffer queues.
-        GEM::regs().rx_qbar.write(
+        self.regs.rx_qbar.write(
            regs::RxQbar::zeroed()
        );
-        GEM::regs().tx_qbar.write(
+        self.regs.tx_qbar.write(
            regs::TxQbar::zeroed()
        );
    }
@ -532,7 +480,7 @@ impl<GEM: Gem> EthInner<GEM> {
        let clocks = Clocks::get();
        let mdc_clk_div = (clocks.cpu_1x() / MAX_MDC) + 1;

-        GEM::regs().net_cfg.write(
+        self.regs.net_cfg.write(
            regs::NetCfg::zeroed()
                .full_duplex(true)
                .gige_en(true)
@ -557,17 +505,17 @@ impl<GEM: Gem> EthInner<GEM> {
            (u32::from(macaddr[3]) << 16) |
            (u32::from(macaddr[4]) << 8) |
            u32::from(macaddr[5]);
-        GEM::regs().spec_addr1_top.write(
+        self.regs.spec_addr1_top.write(
            regs::SpecAddrTop::zeroed()
                .addr_msbs(macaddr_msbs)
        );
-        GEM::regs().spec_addr1_bot.write(
+        self.regs.spec_addr1_bot.write(
            regs::SpecAddrBot::zeroed()
                .addr_lsbs(macaddr_lsbs)
        );


-        GEM::regs().dma_cfg.write(
+        self.regs.dma_cfg.write(
            regs::DmaCfg::zeroed()
                // 1536 bytes
                .ahb_mem_rx_buf_size((MTU >> 6) as u8)
@ -583,7 +531,7 @@ impl<GEM: Gem> EthInner<GEM> {
                .ahb_fixed_burst_len(0x10)
        );

-        GEM::regs().net_ctrl.write(
+        self.regs.net_ctrl.write(
            regs::NetCtrl::zeroed()
                .mgmt_port_en(true)
        );
@ -591,7 +539,7 @@ impl<GEM: Gem> EthInner<GEM> {


    fn wait_phy_idle(&self) {
-        while !GEM::regs().net_status.read().phy_mgmt_idle() {}
+        while !self.regs.net_status.read().phy_mgmt_idle() {}
    }


@ -610,15 +558,17 @@ impl<GEM: Gem> EthInner<GEM> {
                Some(link) => {
                    info!("eth: got {:?}", link);

-                    use phy::{LinkDuplex::Full, LinkSpeed::*};
+                    use phy::LinkSpeed::*;
                    let txclock = match link.speed {
                        S10 => TX_10,
                        S100 => TX_100,
                        S1000 => TX_1000,
                    };
-                    GEM::setup_clock(txclock);
-                    GEM::regs().net_cfg.modify(|_, w| w
-                        .full_duplex(link.duplex == Full)
+                    Eth::<(), ()>::setup_gem0_clock(txclock);
+                    /* .full_duplex(false) doesn't work even if
+                       half duplex has been negotiated. */
+                    self.regs.net_cfg.modify(|_, w| w
+                        .full_duplex(true)
                        .gige_en(link.speed == S1000)
                        .speed(link.speed != S10)
                    );
@ -637,10 +587,10 @@ impl<GEM: Gem> EthInner<GEM> {
    }
 }

-impl<GEM: Gem> PhyAccess for EthInner<GEM> {
+impl<'r> PhyAccess for EthInner<'r> {
    fn read_phy(&mut self, addr: u8, reg: u8) -> u16 {
        self.wait_phy_idle();
-        GEM::regs().phy_maint.write(
+        self.regs.phy_maint.write(
            regs::PhyMaint::zeroed()
                .clause_22(true)
                .operation(regs::PhyOperation::Read)
@ -649,12 +599,12 @@ impl<GEM: Gem> PhyAccess for EthInner<GEM> {
                .must_10(0b10)
        );
        self.wait_phy_idle();
-        GEM::regs().phy_maint.read().data()
+        self.regs.phy_maint.read().data()
    }

    fn write_phy(&mut self, addr: u8, reg: u8, data: u16) {
        self.wait_phy_idle();
-        GEM::regs().phy_maint.write(
+        self.regs.phy_maint.write(
            regs::PhyMaint::zeroed()
                .clause_22(true)
                .operation(regs::PhyOperation::Write)
--- a/libboard_zynq/src/eth/phy/extended_status.rs
+++ b/libboard_zynq/src/eth/phy/extended_status.rs
@ -0,0 +1,59 @@
+use bit_field::BitField;
+use super::{PhyRegister, Link, LinkDuplex, LinkSpeed};
+
+#[derive(Clone, Copy, Debug)]
+/// 1000Base-T Extended Status Register
+pub struct ExtendedStatus(pub u16);
+
+impl ExtendedStatus {
+    pub fn cap_1000base_t_half(&self) -> bool {
+        self.0.get_bit(12)
+    }
+    pub fn cap_1000base_t_full(&self) -> bool {
+        self.0.get_bit(13)
+    }
+    pub fn cap_1000base_x_half(&self) -> bool {
+        self.0.get_bit(14)
+    }
+    pub fn cap_1000base_x_full(&self) -> bool {
+        self.0.get_bit(12)
+    }
+
+    pub fn get_link(&self) -> Option<Link> {
+        if self.cap_1000base_t_half() {
+            Some(Link {
+                speed: LinkSpeed::S1000,
+                duplex: LinkDuplex::Half,
+            })
+        } else if self.cap_1000base_t_full() {
+            Some(Link {
+                speed: LinkSpeed::S1000,
+                duplex: LinkDuplex::Full,
+            })
+        } else if self.cap_1000base_x_half() {
+            Some(Link {
+                speed: LinkSpeed::S1000,
+                duplex: LinkDuplex::Half,
+            })
+        } else if self.cap_1000base_x_full() {
+            Some(Link {
+                speed: LinkSpeed::S1000,
+                duplex: LinkDuplex::Full,
+            })
+        } else {
+            None
+        }
+    }
+}
+
+impl PhyRegister for ExtendedStatus {
+    fn addr() -> u8 {
+        0xF
+    }
+}
+
+impl From<u16> for ExtendedStatus {
+    fn from(value: u16) -> Self {
+        ExtendedStatus(value)
+    }
+}
--- a/libboard_zynq/src/eth/phy/mod.rs
+++ b/libboard_zynq/src/eth/phy/mod.rs
@ -2,10 +2,10 @@ pub mod id;
 use id::{identify_phy, PhyIdentifier};
 mod status;
 pub use status::Status;
+mod extended_status;
+pub use extended_status::ExtendedStatus;
 mod control;
 pub use control::Control;
-mod pssr;
-pub use pssr::PSSR;

 #[derive(Clone, Debug, PartialEq)]
 pub struct Link {
@ -39,36 +39,43 @@ pub struct Phy {

 #[derive(Clone, Copy)]
 pub enum PhyDevice {
-    Marvell88E1116R,
+    Marvel88E1116R,
    Rtl8211E,
 }

-const OUI_MARVELL: u32 = 0x005043;
+const OUI_MARVEL: u32 = 0x005043;
 const OUI_REALTEK: u32 = 0x000732;

 impl Phy {
    /// Probe all addresses on MDIO for a known PHY
    pub fn find<PA: PhyAccess>(pa: &mut PA) -> Option<Phy> {
-        (1..32).filter_map(|addr| {
-            match identify_phy(pa, addr) {
+        for addr in 1..32 {
+            let device = match identify_phy(pa, addr) {
                Some(PhyIdentifier {
-                    oui: OUI_MARVELL,
+                    oui: OUI_MARVEL,
                    model: 36,
                    ..
-                }) => Some(PhyDevice::Marvell88E1116R),
+                }) => Some(PhyDevice::Marvel88E1116R),
                Some(PhyIdentifier {
                    oui: OUI_REALTEK,
                    model: 0b010001,
                    rev: 0b0101,
                }) => Some(PhyDevice::Rtl8211E),
                _ => None,
-            }.map(|device| Phy { addr, device })
-        }).next()
+            };
+            match device {
+                Some(device) =>
+                    return Some(Phy { addr, device }),
+                None => {}
+            }
+        }
+
+        None
    }

    pub fn name(&self) -> &'static str {
        match self.device {
-            PhyDevice::Marvell88E1116R => &"Marvell 88E1116R",
+            PhyDevice::Marvel88E1116R => &"Marvel 88E1116R",
            PhyDevice::Rtl8211E => &"RTL8211E",
        }
    }
@ -113,8 +120,12 @@ impl Phy {
        if !status.link_status() {
            None
        } else if status.cap_1000base_t_extended_status() {
-            let phy_status: PSSR = self.read_reg(pa);
-            phy_status.get_link()
+            let ext_status: ExtendedStatus = self.read_reg(pa);
+            if let Some(link) = ext_status.get_link() {
+                Some(link)
+            } else {
+                status.get_link()
+            }
        } else {
            status.get_link()
        }
--- a/libboard_zynq/src/eth/phy/pssr.rs
+++ b/libboard_zynq/src/eth/phy/pssr.rs
@ -1,52 +0,0 @@
-use bit_field::BitField;
-use super::{PhyRegister, Link, LinkDuplex, LinkSpeed};
-
-#[derive(Clone, Copy, Debug)]
-/// PHY-Specific Status Register
-pub struct PSSR(pub u16);
-
-impl PSSR {
-    pub fn link(&self) -> bool {
-        self.0.get_bit(10)
-    }
-
-    pub fn duplex(&self) -> LinkDuplex {
-        if self.0.get_bit(13) {
-            LinkDuplex::Full
-        } else {
-            LinkDuplex::Half
-        }
-    }
-
-    pub fn speed(&self) -> Option<LinkSpeed> {
-        match self.0.get_bits(14..=15) {
-            0b00 => Some(LinkSpeed::S10),
-            0b01 => Some(LinkSpeed::S100),
-            0b10 => Some(LinkSpeed::S1000),
-            _ => None,
-        }
-    }
-
-    pub fn get_link(&self) -> Option<Link> {
-        if self.link() {
-            Some(Link {
-                speed: self.speed()?,
-                duplex: self.duplex(),
-            })
-        } else {
-            None
-        }
-    }
-}
-
-impl PhyRegister for PSSR {
-    fn addr() -> u8 {
-        0x11
-    }
-}
-
-impl From<u16> for PSSR {
-    fn from(value: u16) -> Self {
-        PSSR(value)
-    }
-}
--- a/libboard_zynq/src/gic.rs
+++ b/libboard_zynq/src/gic.rs
@ -1,150 +0,0 @@
-//! ARM Generic Interrupt Controller
-
-use bit_field::BitField;
-use libregister::{RegisterW, RegisterRW, RegisterR};
-use super::mpcore;
-
-#[derive(Debug, Clone, Copy)]
-pub struct InterruptId(pub u8);
-
-#[derive(Debug, Clone, Copy)]
-#[repr(u8)]
-pub enum CPUCore {
-    Core0 = 0b01,
-    Core1 = 0b10
-}
-
-#[derive(Debug, Clone, Copy)]
-pub struct TargetCPU(u8);
-
-impl TargetCPU {
-    pub const fn none() -> TargetCPU {
-        TargetCPU(0)
-    }
-
-    pub const fn and(self, other: TargetCPU) -> TargetCPU {
-        TargetCPU(self.0 | other.0)
-    }
-}
-
-impl From<CPUCore> for TargetCPU {
-    fn from(core: CPUCore) -> Self {
-        TargetCPU(core as u8)
-    }
-}
-
-pub enum TargetList {
-    CPUList(TargetCPU),
-    Others,
-    This
-}
-
-impl From<CPUCore> for TargetList {
-    fn from(core: CPUCore) -> Self {
-        TargetList::CPUList(TargetCPU(core as u8))
-    }
-}
-
-impl From<TargetCPU> for TargetList {
-    fn from(cpu: TargetCPU) -> Self {
-        TargetList::CPUList(cpu)
-    }
-}
-
-#[derive(Debug, Clone, Copy)]
-pub enum InterruptSensitivity {
-    Level,
-    Edge,
-}
-
-pub struct InterruptController {
-    mpcore: &'static mut mpcore::RegisterBlock,
-}
-
-impl InterruptController {
-    pub fn new(mpcore: &'static mut mpcore::RegisterBlock) -> Self {
-        InterruptController { mpcore }
-    }
-
-    pub fn disable_interrupts(&mut self) {
-        self.mpcore.iccicr.modify(|_, w| w.enable_ns(false)
-                                          .enable_s(false));
-        // FIXME: Should we disable the distributor globally when we disable interrupt (for a single
-        // core)?
-        // self.mpcore.icddcr.modify(|_, w| w.enable_secure(false)
-        //                                   .enable_non_secure(false));
-    }
-
-    /// enable interrupt signaling
-    pub fn enable_interrupts(&mut self) {
-        self.mpcore.iccicr.modify(|_, w| w.enable_ns(true)
-                                          .enable_s(true));
-        self.mpcore.icddcr.modify(|_, w| w.enable_secure(true));
-
-        // Enable all interrupts except those of the lowest priority.
-        self.mpcore.iccpmr.write(mpcore::ICCPMR::zeroed().priority(0xFF));
-    }
-
-    /// send software generated interrupt
-    pub fn send_sgi(&mut self, id: InterruptId, targets: TargetList) {
-        assert!(id.0 < 16);
-        self.mpcore.icdsgir.modify(|_, w| match targets {
-            TargetList::CPUList(list) => w.target_list_filter(0).cpu_target_list(list.0),
-            TargetList::Others => w.target_list_filter(0b01),
-            TargetList::This => w.target_list_filter(0b10)
-        }.sgiintid(id.0).satt(false));
-    }
-
-    /// enable the interrupt *for this core*.
-    /// Not needed for SGI.
-    pub fn enable(&mut self, id: InterruptId, target_cpu: CPUCore, sensitivity: InterruptSensitivity, priority: u8) {
-        // only 5 bits of the priority is useful
-        assert!(priority < 32);
-
-        self.disable_interrupts();
-
-        // enable
-        let m = (id.0 >> 5) as usize;
-        let n = (id.0 & 0x1F) as usize;
-        assert!(m < 3);
-        unsafe {
-            self.mpcore.icdiser[m].modify(|mut icdiser| *icdiser.set_bit(n, true));
-        }
-
-        // target cpu
-        let m = (id.0 >> 2) as usize;
-        let n = (8 * (id.0 & 3)) as usize;
-        unsafe {
-            self.mpcore.icdiptr[m].modify(|mut icdiptr| *icdiptr.set_bits(n..=n+1, target_cpu as u32 + 1));
-        }
-
-        // sensitivity
-        let m = (id.0 >> 4) as usize;
-        let n = (2 * (id.0 & 0xF)) as usize;
-        unsafe {
-            self.mpcore.icdicfr[m].modify(|mut icdicfr| *icdicfr.set_bits(n..=n+1, match sensitivity {
-                InterruptSensitivity::Level => 0b00,
-                InterruptSensitivity::Edge  => 0b10,
-            }));
-        }
-
-        // priority
-        let offset = (id.0 % 4) * 8;
-        let priority: u32 = (priority as u32) << (offset + 3);
-        let mask: u32 = 0xFFFFFFFF ^ (0xFF << offset);
-        unsafe {
-            self.mpcore.icdipr[id.0 as usize / 4].modify(|v| (v & mask) | priority);
-        }
-
-        self.enable_interrupts();
-    }
-
-    pub fn end_interrupt(&mut self, id: InterruptId) {
-        self.mpcore.icceoir.modify(|_, w| w.eoiintid(id.0 as u32));
-    }
-
-    pub fn get_interrupt_id(&self) -> InterruptId {
-        InterruptId(self.mpcore.icciar.read().ackintid() as u8)
-    }
-
-}
--- a/libboard_zynq/src/i2c/eeprom.rs
+++ b/libboard_zynq/src/i2c/eeprom.rs
@ -1,107 +0,0 @@
-use super::I2C;
-use crate::time::Milliseconds;
-use embedded_hal::timer::CountDown;
-
-pub struct EEPROM<'a> {
-    i2c: &'a mut I2C,
-    port: u8,
-    address: u8,
-    page_size: u8,
-    count_down: crate::timer::global::CountDown<Milliseconds>
-}
-
-impl<'a> EEPROM<'a> {
-    #[cfg(feature = "target_zc706")]
-    pub fn new(i2c: &'a mut I2C, page_size: u8) -> Self {
-        EEPROM {
-            i2c: i2c,
-            port: 2,
-            address: 0b1010100,
-            page_size: page_size,
-            count_down: unsafe { crate::timer::GlobalTimer::get() }.countdown()
-        }
-    }
-
-    #[cfg(feature = "target_zc706")]
-    fn select(&mut self) -> Result<(), &'static str> {
-        let mask: u16 = 1 << self.port;
-        self.i2c.pca9548_select(0b1110100, mask as u8)?;
-        Ok(())
-    }
-
-    /// Random read
-    pub fn read<'r>(&mut self, addr: u8, buf: &'r mut [u8]) -> Result<(), &'static str> {
-        self.select()?;
-
-        self.i2c.start()?;
-        self.i2c.write(self.address << 1)?;
-        self.i2c.write(addr)?;
-
-        self.i2c.restart()?;
-        self.i2c.write((self.address << 1) | 1)?;
-        let buf_len = buf.len();
-        for (i, byte) in buf.iter_mut().enumerate() {
-            *byte = self.i2c.read(i < buf_len - 1)?;
-        }
-
-        self.i2c.stop()?;
-
-        Ok(())
-    }
-
-    /// Smart multi-page writing
-    /// Using the "Page Write" function of an EEPROM, the memory region for each transaction
-    /// (i.e. from byte `addr` to byte `addr+buf.len()`) should fit under each page 
-    /// (i.e. `addr+buf.len()` < `addr/self.page_size+1`); otherwise, a roll-oever occurs, 
-    /// where bytes beyond the page end. This smart function takes care of the scenario to avoid
-    /// any roll-over when writing ambiguous memory regions.
-    pub fn write(&mut self, addr: u8, buf: &[u8]) -> Result<(), &'static str> {
-        self.select()?;
-
-        let buf_len = buf.len();
-        let mut pb: u8 = addr % self.page_size;
-        for (i, byte) in buf.iter().enumerate() {
-            if (i == 0) || (pb == 0) {
-                self.i2c.start()?;
-                self.i2c.write(self.address << 1)?;
-                self.i2c.write(addr + (i as u8))?;
-            }
-            self.i2c.write(*byte)?;
-            pb += 1;
-
-            if (i == buf_len-1) || (pb == self.page_size) {
-                self.i2c.stop()?;
-                self.poll(1_000)?;
-                pb = 0;
-            }
-        }
-
-        Ok(())
-    }
-
-    /// Poll
-    pub fn poll(&mut self, timeout_ms: u64) -> Result<(), &'static str> {
-        self.select()?;
-
-        self.count_down.start(Milliseconds(timeout_ms));
-        loop {
-            self.i2c.start()?;
-            let ack = self.i2c.write(self.address << 1)?;
-            self.i2c.stop()?;
-            if ack {
-                break
-            };
-            if !self.count_down.waiting() {
-                return Err("I2C polling timeout")
-            }
-        }
-
-        Ok(())
-    }
-
-    pub fn read_eui48<'r>(&mut self) -> Result<[u8; 6], &'static str> {
-        let mut buffer = [0u8; 6];
-        self.read(0xFA, &mut buffer)?;
-        Ok(buffer)
-    }
-}
--- a/libboard_zynq/src/i2c/mod.rs
+++ b/libboard_zynq/src/i2c/mod.rs
@ -1,235 +0,0 @@
-//! I2C Bit-banging Controller
-
-mod regs;
-pub mod eeprom;
-use super::clocks::Clocks;
-use super::slcr;
-use super::time::Microseconds;
-use embedded_hal::timer::CountDown;
-use libregister::{RegisterR, RegisterRW, RegisterW};
-
-const INVALID_BUS: &'static str = "Invalid I2C bus";
-
-pub struct I2C {
-    regs: regs::RegisterWrapper,
-    count_down: super::timer::global::CountDown<Microseconds>
-}
-
-impl I2C {
-    #[cfg(feature = "target_zc706")]
-    pub fn i2c() -> Self {
-        // Route I2C 0 SCL / SDA Signals to MIO Pins 50 / 51
-        slcr::RegisterBlock::unlocked(|slcr| {
-            // SCL
-            slcr.mio_pin_50.write(
-                slcr::MioPin50::zeroed()
-                    .l3_sel(0b000)  // as GPIO 50
-                    .io_type(slcr::IoBufferType::Lvcmos18)
-                    .pullup(true)
-                    .disable_rcvr(true)
-            );
-            // SDA
-            slcr.mio_pin_51.write(
-                slcr::MioPin51::zeroed()
-                    .l3_sel(0b000)  // as GPIO 51
-                    .io_type(slcr::IoBufferType::Lvcmos18)
-                    .pullup(true)
-                    .disable_rcvr(true)
-            );
-            // Reset
-            slcr.gpio_rst_ctrl.reset_gpio();
-        });
-
-        Self::ctor_common(0xFFFF - 0x000C)
-    }
-
-    fn ctor_common(gpio_output_mask: u16) -> Self {
-        // Setup register block
-        let clocks = Clocks::get();
-        let self_ = Self {
-            regs: regs::RegisterWrapper::new(),
-            count_down: unsafe { super::timer::GlobalTimer::get() }.countdown()
-        };
-
-        // Setup GPIO output mask
-        self_.regs.gpio_output_mask.modify(|_, w| {
-            w.mask(gpio_output_mask)
-        });
-        // Setup GPIO driver direction
-        self_.regs.gpio_direction.modify(|_, w| {
-            w.scl(true).sda(true)
-        });
-
-        self_
-    }
-
-    /// Delay for I2C operations, simple wrapper for nb.
-    fn delay_us(&mut self, us: u64) {
-        self.count_down.start(Microseconds(us));
-        nb::block!(self.count_down.wait()).unwrap();
-    }
-
-    fn half_period(&mut self) { self.delay_us(100) }
-
-    fn sda_i(&mut self) -> bool {
-        self.regs.gpio_input.read().sda()
-    }
-
-    fn scl_i(&mut self) -> bool {
-        self.regs.gpio_input.read().scl()
-    }
-
-    fn sda_oe(&mut self, oe: bool) {
-        self.regs.gpio_output_enable.modify(|_, w| {
-             w.sda(oe)
-        })
-    }
-
-    fn sda_o(&mut self, o: bool) {
-        self.regs.gpio_output_mask.modify(|_, w| {
-             w.sda_o(o)
-        })
-    }
-
-    fn scl_oe(&mut self, oe: bool) {
-        self.regs.gpio_output_enable.modify(|_, w| {
-             w.scl(oe)
-        })
-    }
-
-    fn scl_o(&mut self, o: bool) {
-        self.regs.gpio_output_mask.modify(|_, w| {
-             w.scl_o(o)
-        })
-    }
-
-    pub fn init(&mut self) -> Result<(), &'static str> {
-        self.scl_oe(false);
-        self.sda_oe(false);
-        self.scl_o(false);
-        self.sda_o(false);
-
-        // Check the I2C bus is ready
-        self.half_period();
-        self.half_period();
-        if !self.sda_i() {
-            // Try toggling SCL a few times
-            for _bit in 0..8 {
-                self.scl_oe(true);
-                self.half_period();
-                self.scl_oe(false);
-                self.half_period();
-            }
-        }
-
-        if !self.sda_i() {
-            return Err("SDA is stuck low and doesn't get unstuck");
-        }
-        if !self.scl_i() {
-            return Err("SCL is stuck low and doesn't get unstuck");
-        }
-        // postcondition: SCL and SDA high
-        Ok(())
-    }
-
-    pub fn start(&mut self) -> Result<(), &'static str> {
-        // precondition: SCL and SDA high
-        if !self.scl_i() {
-            return Err("SCL is stuck low and doesn't get unstuck");
-        }
-        if !self.sda_i() {
-            return Err("SDA arbitration lost");
-        }
-        self.sda_oe(true);
-        self.half_period();
-        self.scl_oe(true);
-        // postcondition: SCL and SDA low
-        Ok(())
-    }
-
-    pub fn restart(&mut self) -> Result<(), &'static str> {
-        // precondition SCL and SDA low
-        self.sda_oe(false);
-        self.half_period();
-        self.scl_oe(false);
-        self.half_period();
-        self.start()?;
-        // postcondition: SCL and SDA low
-        Ok(())
-    }
-
-    pub fn stop(&mut self) -> Result<(), &'static str> {
-        // precondition: SCL and SDA low
-        self.half_period();
-        self.scl_oe(false);
-        self.half_period();
-        self.sda_oe(false);
-        self.half_period();
-        if !self.sda_i() {
-            return Err("SDA arbitration lost");
-        }
-        // postcondition: SCL and SDA high
-        Ok(())
-    }
-
-    pub fn write(&mut self, data: u8) -> Result<bool, &'static str> {
-        // precondition: SCL and SDA low
-        // MSB first
-        for bit in (0..8).rev() {
-            self.sda_oe(data & (1 << bit) == 0);
-            self.half_period();
-            self.scl_oe(false);
-            self.half_period();
-            self.scl_oe(true);
-        }
-        self.sda_oe(false);
-        self.half_period();
-        self.scl_oe(false);
-        self.half_period();
-        // Read ack/nack
-        let ack = !self.sda_i();
-        self.scl_oe(true);
-        self.sda_oe(true);
-        // postcondition: SCL and SDA low
-
-        Ok(ack)
-    }
-
-    pub fn read(&mut self, ack: bool) -> Result<u8, &'static str> {
-        // precondition: SCL and SDA low
-        self.sda_oe(false);
-
-        let mut data: u8 = 0;
-
-        // MSB first
-        for bit in (0..8).rev() {
-            self.half_period();
-            self.scl_oe(false);
-            self.half_period();
-            if self.sda_i() { data |= 1 << bit }
-            self.scl_oe(true);
-        }
-        // Send ack/nack
-        self.sda_oe(ack);
-        self.half_period();
-        self.scl_oe(false);
-        self.half_period();
-        self.scl_oe(true);
-        self.sda_oe(true);
-        // postcondition: SCL and SDA low
-
-        Ok(data)
-    }
-
-    pub fn pca9548_select(&mut self, address: u8, channels: u8) -> Result<(), &'static str> {
-        self.start()?;
-        if !self.write(address << 1)? {
-            return Err("PCA9548 failed to ack write address")
-        }
-        if !self.write(channels)? {
-            return Err("PCA9548 failed to ack control word")
-        }
-        self.stop()?;
-        Ok(())
-    }
-}
--- a/libboard_zynq/src/i2c/regs.rs
+++ b/libboard_zynq/src/i2c/regs.rs
@ -1,93 +0,0 @@
-use volatile_register::{RO, WO, RW};
-
-use libregister::{
-    register, register_at,
-    register_bit, register_bits
-};
-
-// With reference to:
-//
-// artiq:artiq/gateware/targets/kasli.py:
-// self.submodules.i2c = gpio.GPIOTristate([i2c.scl, i2c.sda])
-//
-// misoc:misoc/cores/gpio.py:
-// class GPIOTristate(Module, AutoCSR):
-//    def __init__(self, signals, reset_out=0, reset_oe=0):
-//        l = len(signals)
-//        self._in = CSRStatus(l)
-//        self._out = CSRStorage(l, reset=reset_out)
-//        self._oe = CSRStorage(l, reset=reset_oe)
-// 
-// Hence, using GPIOs as SCL and SDA GPIOs respectively.
-//
-// Current compatibility:
-// zc706: GPIO 50, 51 == SCL, SDA
-
-pub struct RegisterWrapper {
-    pub gpio_output_mask: &'static mut GPIOOutputMask,
-    pub gpio_input: &'static mut GPIOInput,
-    pub gpio_direction: &'static mut GPIODirection,
-    pub gpio_output_enable: &'static mut GPIOOutputEnable,
-}
-
-impl RegisterWrapper {
-    pub fn new() -> Self {
-        Self {
-            gpio_output_mask: GPIOOutputMask::new(),
-            gpio_input: GPIOInput::new(),
-            gpio_direction: GPIODirection::new(),
-            gpio_output_enable: GPIOOutputEnable::new()
-        }
-    }
-}
-
-// MASK_DATA_1_MSW:
-// Maskable output data for MIO[53:48]
-register!(gpio_output_mask, GPIOOutputMask, RW, u32);
-#[cfg(feature = "target_zc706")]
-register_at!(GPIOOutputMask, 0xE000A00C, new);
-// Output for SCL
-#[cfg(feature = "target_zc706")]
-register_bit!(gpio_output_mask, scl_o, 2);
-// Output for SDA
-#[cfg(feature = "target_zc706")]
-register_bit!(gpio_output_mask, sda_o, 3);
-// Mask for keeping bits except SCL and SDA unchanged
-#[cfg(feature = "target_zc706")]
-register_bits!(gpio_output_mask, mask, u16, 16, 31);
-
-// DATA_1_RO:
-// Input data for MIO[53:32]
-register!(gpio_input, GPIOInput, RO, u32);
-#[cfg(feature = "target_zc706")]
-register_at!(GPIOInput, 0xE000A064, new);
-// Input for SCL
-#[cfg(feature = "target_zc706")]
-register_bit!(gpio_input, scl, 18);
-// Input for SDA
-#[cfg(feature = "target_zc706")]
-register_bit!(gpio_input, sda, 19);
-
-// DIRM_1:
-// Direction mode for MIO[53:32]; 0/1 = in/out
-register!(gpio_direction, GPIODirection, RW, u32);
-#[cfg(feature = "target_zc706")]
-register_at!(GPIODirection, 0xE000A244, new);
-// Direction for SCL
-#[cfg(feature = "target_zc706")]
-register_bit!(gpio_direction, scl, 18);
-// Direction for SDA
-#[cfg(feature = "target_zc706")]
-register_bit!(gpio_direction, sda, 19);
-
-// OEN_1:
-// Output enable for MIO[53:32]
-register!(gpio_output_enable, GPIOOutputEnable, RW, u32);
-#[cfg(feature = "target_zc706")]
-register_at!(GPIOOutputEnable, 0xE000A248, new);
-// Output enable for SCL
-#[cfg(feature = "target_zc706")]
-register_bit!(gpio_output_enable, scl, 18);
-// Output enable for SDA
-#[cfg(feature = "target_zc706")]
-register_bit!(gpio_output_enable, sda, 19);
--- a/libboard_zynq/src/lib.rs
+++ b/libboard_zynq/src/lib.rs
@ -15,12 +15,9 @@ pub mod axi_hp;
 pub mod axi_gp;
 pub mod ddr;
 pub mod mpcore;
-pub mod gic;
 pub mod flash;
 pub mod time;
 pub mod timer;
 pub mod sdio;
-#[cfg(feature = "target_zc706")]
-pub mod i2c;
 pub mod logger;
 pub mod ps7_init;
--- a/libboard_zynq/src/mpcore.rs
+++ b/libboard_zynq/src/mpcore.rs
@ -8,141 +8,48 @@ use libregister::{

 #[repr(C)]
 pub struct RegisterBlock {
-    /// SCU Control Register
    pub scu_control: ScuControl,
-    /// SCU Configuration Register
-    pub scu_config: ScuConfig,
-    /// SCU CPU Power Status Register
-    pub scu_cpu_power_status: SCUCPUPowerStatusRegister,
-    /// SCU Invalidate All Registers in Secure State
+    pub scu_config: RO<u32>,
+    pub scu_cpu_power: RW<u32>,
    pub scu_invalidate: ScuInvalidate,
-    unused0: [u32; 12],
-    /// Filtering Start Address Register
-    pub filtering_start_address: FilteringStartAddressRegister,
-    /// Defined by FILTEREND input
-    pub filtering_end_address: FilteringEndAddressRegister,
-    unused1: [u32; 2],
-    /// SCU Access Control (SAC) Register
-    pub scu_access_control_sac: SCUAccessControlRegisterSAC,
-    /// SCU Non-secure Access Control Register SNSAC
-    pub scu_non_secure_access_control: SCUNonSecureAccessControlRegister,
-    unused2: [u32; 42],
-    /// CPU Interface Control Register
-    pub iccicr: ICCICR,
-    /// Interrupt Priority Mask Register
-    pub iccpmr: ICCPMR,
-    /// Binary Point Register
-    pub iccbpr: ICCBPR,
-    /// Interrupt Acknowledge Register
-    pub icciar: ICCIAR,
-    /// End Of Interrupt Register
-    pub icceoir: ICCEOIR,
-    /// Running Priority Register
-    pub iccrpr: ICCRPR,
-    /// Highest Pending Interrupt Register
-    pub icchpir: ICCHPIR,
-    /// Aliased Non-secure Binary Point Register
-    pub iccabpr: ICCABPR,
-    unused3: [u32; 55],
-    /// CPU Interface Implementer Identification Register
-    pub iccidr: ICCIDR,
-    /// Global Timer Counter Register 0
+    reserved0: [u32; 12],
+    pub filter_start: RW<u32>,
+    pub filter_end: RW<u32>,
+    reserved1: [u32; 2],
+    pub scu_access_control: RW<u32>,
+    pub scu_non_secure_access_control: RW<u32>,
+    reserved2: [u32; 42],
+    pub iccicr: RW<u32>,
+    pub iccpmw: RW<u32>,
+    pub iccbpr: RW<u32>,
+    pub icciar: RW<u32>,
+    pub icceoir: RW<u32>,
+    pub iccrpr: RW<u32>,
+    pub icchpir: RW<u32>,
+    pub iccabpr: RW<u32>,
+    reserved3: [u32; 55],
+    pub iccidr: RW<u32>,
    pub global_timer_counter0: ValueRegister,
    pub global_timer_counter1: ValueRegister,
-    /// Global Timer Control Register
    pub global_timer_control: GlobalTimerControl,
-    /// Global Timer Interrupt Status Register
-    pub global_timer_interrupt_status: GlobalTimerInterruptStatusRegister,
-    /// Comparator Value Register_0
+    pub global_timer_interrupt_status: RW<u32>,
    pub comparator_value0: ValueRegister,
    pub comparator_value1: ValueRegister,
-    /// Auto-increment Register
-    pub auto_increment: RW<u32>,
-    unused4: [u32; 249],
-    /// Private Timer Load Register
-    pub private_timer_load: RW<u32>,
-    /// Private Timer Counter Register
-    pub private_timer_counter: RW<u32>,
-    /// Private Timer Control Register
-    pub private_timer_control: PrivateTimerControlRegister,
-    /// Private Timer Interrupt Status Register
-    pub private_timer_interrupt_status: PrivateTimerInterruptStatusRegister,
-    unused5: [u32; 4],
-    /// Watchdog Load Register
-    pub watchdog_load: RW<u32>,
-    /// Watchdog Counter Register
-    pub watchdog_counter: RW<u32>,
-    /// Watchdog Control Register
-    pub watchdog_control: WatchdogControlRegister,
-    /// Watchdog Interrupt Status Register
-    pub watchdog_interrupt_status: WatchdogInterruptStatusRegister,
-    /// Watchdog Reset Status Register
-    pub watchdog_reset_status: WatchdogResetStatusRegister,
-    /// Watchdog Disable Register
-    pub watchdog_disable: RW<u32>,
-    unused6: [u32; 626],
-    /// Distributor Control Register
-    pub icddcr: ICDDCR,
-    /// Interrupt Controller Type Register
-    pub icdictr: ICDICTR,
-    /// Distributor Implementer Identification Register
-    pub icdiidr: ICDIIDR,
-    unused7: [u32; 29],
-    /// Interrupt Security Register
-    pub icdisr0: RW<u32>,
-    pub icdisr1: RW<u32>,
-    pub icdisr2: RW<u32>,
-    unused8: [u32; 29],
-    /// Interrupt Set-enable Registers
-    pub icdiser: [RW<u32>; 3],
-    unused9: [u32; 29],
-    /// Interrupt Clear-Enable Register 0
-    pub icdicer0: RW<u32>,
-    /// Interrupt Clear-Enable Register 1
-    pub icdicer1: RW<u32>,
-    /// Interrupt Clear-Enable Register 2
-    pub icdicer2: RW<u32>,
-    unused10: [u32; 29],
-    /// Interrupt Set-pending Register
-    pub icdispr0: RW<u32>,
-    pub icdispr1: RW<u32>,
-    pub icdispr2: RW<u32>,
-    unused11: [u32; 29],
-    /// Interrupt Clear-Pending Register
-    pub icdicpr0: RW<u32>,
-    pub icdicpr1: RW<u32>,
-    pub icdicpr2: RW<u32>,
-    unused12: [u32; 29],
-    /// Active Bit register
-    pub icdabr0: RW<u32>,
-    pub icdabr1: RW<u32>,
-    pub icdabr2: RW<u32>,
-    unused13: [u32; 61],
-    /// Interrupt Priority Register
-    pub icdipr: [RW<u32>; 24],
-    unused14: [u32; 232],
-    /// Interrupt Processor Targets Registers
-    pub icdiptr: [RW<u32>; 24],
-    unused15: [u32; 232],
-    /// Interrupt Configuration Registers
-    pub icdicfr: [RW<u32>; 6],
-    unused16: [u32; 58],
-    /// PPI Status Register
-    pub ppi_status: PpiStatus,
-    /// SPI Status Register 0
-    pub spi_status_0: RO<u32>,
-    /// SPI Status Register 1
-    pub spi_status_1: RO<u32>,
-    unused17: [u32; 125],
-    /// Software Generated Interrupt Register
-    pub icdsgir: ICDSGIR,
+    pub auto_increment: ValueRegister,
+    reserved4: [u32; 249],
+    pub private_timer_load: ValueRegister,
+    pub private_timer_counter: ValueRegister,
+    pub private_timer_control: RW<u32>,
+    pub private_timer_interrupt_status: RW<u32>,
+    reserved5: [u32; 4],
+    pub watchdog_load: ValueRegister,
+    pub watchdog_counter: ValueRegister,
+    pub watchdog_control: RW<u32>,
+    pub watchdog_interrupt_status: RW<u32>,
+    // there is plenty more (unimplemented)
 }
-
 register_at!(RegisterBlock, 0xF8F00000, new);

-register!(value_register, ValueRegister, RW, u32);
-register_bits!(value_register, value, u32, 0, 31);
-
 register!(scu_control, ScuControl, RW, u32);
 register_bit!(scu_control, ic_standby_enable, 6);
 register_bit!(scu_control, scu_standby_enable, 5);
@ -158,17 +65,6 @@ impl ScuControl {
    }
 }

-register!(scu_config, ScuConfig, RO, u32);
-register_bits!(scu_config, tag_ram_sizes, u8, 8, 15);
-register_bits!(scu_config, cpus_smp, u8, 4, 7);
-register_bits!(scu_config, cpu_number, u8, 0, 1);
-
-register!(scu_cpu_power_status, SCUCPUPowerStatusRegister, RW, u32);
-register_bits!(scu_cpu_power_status, cpu3_status, u8, 24, 25);
-register_bits!(scu_cpu_power_status, cpu2_status, u8, 16, 17);
-register_bits!(scu_cpu_power_status, cpu1_status, u8, 8, 9);
-register_bits!(scu_cpu_power_status, cpu0_status, u8, 0, 1);
-
 register!(scu_invalidate, ScuInvalidate, WO, u32);
 register_bits!(scu_invalidate, cpu0_ways, u8, 0, 3);
 register_bits!(scu_invalidate, cpu1_ways, u8, 4, 7);
@ -192,71 +88,8 @@ impl ScuInvalidate {
    }
 }

-register!(filtering_start_address, FilteringStartAddressRegister, RW, u32);
-register_bits!(filtering_start_address, filtering_start_address, u32, 20, 31);
-register_bits!(filtering_start_address, sbz, u32, 0, 19);
-
-register!(filtering_end_address, FilteringEndAddressRegister, RW, u32);
-register_bits!(filtering_end_address, filtering_end_address, u32, 20, 31);
-register_bits!(filtering_end_address, sbz, u32, 0, 19);
-
-register!(scu_access_control_sac, SCUAccessControlRegisterSAC, RW, u32);
-register_bit!(scu_access_control_sac, cp_u3, 3);
-register_bit!(scu_access_control_sac, cp_u2, 2);
-register_bit!(scu_access_control_sac, cp_u1, 1);
-register_bit!(scu_access_control_sac, cp_u0, 0);
-
-register!(scu_non_secure_access_control, SCUNonSecureAccessControlRegister, RO, u32);
-register_bits!(scu_non_secure_access_control, sbz, u32, 12, 31);
-register_bit!(scu_non_secure_access_control, cpu3_global_timer, 11);
-register_bit!(scu_non_secure_access_control, cpu2_global_timer, 10);
-register_bit!(scu_non_secure_access_control, cpu1_global_timer, 9);
-register_bit!(scu_non_secure_access_control, cpu0_global_timer, 8);
-register_bit!(scu_non_secure_access_control, private_timers_for_cpu3, 7);
-register_bit!(scu_non_secure_access_control, private_timers_for_cpu2, 6);
-register_bit!(scu_non_secure_access_control, private_timers_for_cpu1, 5);
-register_bit!(scu_non_secure_access_control, private_timers_for_cpu0, 4);
-register_bit!(scu_non_secure_access_control, component_access_for_cpu3, 3);
-register_bit!(scu_non_secure_access_control, component_access_for_cpu2, 2);
-register_bit!(scu_non_secure_access_control, component_access_for_cpu1, 1);
-register_bit!(scu_non_secure_access_control, component_access_for_cpu0, 0);
-
-register!(iccicr, ICCICR, RW, u32);
-register_bit!(iccicr, sbpr, 4);
-register_bit!(iccicr, fiq_en, 3);
-register_bit!(iccicr, ack_ctl, 2);
-register_bit!(iccicr, enable_ns, 1);
-register_bit!(iccicr, enable_s, 0);
-
-register!(iccpmr, ICCPMR, RW, u32);
-register_bits!(iccpmr, priority, u8, 0, 7);
-
-register!(iccbpr, ICCBPR, RW, u32);
-register_bits!(iccbpr, binary_point, u8, 0, 2);
-
-register!(icciar, ICCIAR, RW, u32);
-register_bits!(icciar, cpuid, u8, 10, 12);
-register_bits!(icciar, ackintid, u32, 0, 9);
-
-register!(icceoir, ICCEOIR, RW, u32);
-register_bits!(icceoir, cpuid, u8, 10, 12);
-register_bits!(icceoir, eoiintid, u32, 0, 9);
-
-register!(iccrpr, ICCRPR, RW, u32);
-register_bits!(iccrpr, priority, u8, 0, 7);
-
-register!(icchpir, ICCHPIR, RW, u32);
-register_bits!(icchpir, cpuid, u8, 10, 12);
-register_bits!(icchpir, pendintid, u32, 0, 9);
-
-register!(iccabpr, ICCABPR, RW, u32);
-register_bits!(iccabpr, binary_point, u8, 0, 2);
-
-register!(iccidr, ICCIDR, RO, u32);
-register_bits!(iccidr, part_number, u32, 20, 31);
-register_bits!(iccidr, architecture_version, u8, 16, 19);
-register_bits!(iccidr, revision_number, u8, 12, 15);
-register_bits!(iccidr, implementer, u32, 0, 11);
+register!(value_register, ValueRegister, RW, u32);
+register_bits!(value_register, value, u32, 0, 31);

 register!(global_timer_control, GlobalTimerControl, RW, u32);
 register_bits!(global_timer_control, prescaler, u8, 8, 15);
@ -264,58 +97,3 @@ register_bit!(global_timer_control, auto_increment_mode, 3);
 register_bit!(global_timer_control, irq_enable, 2);
 register_bit!(global_timer_control, comp_enablea, 1);
 register_bit!(global_timer_control, timer_enable, 0);
-
-register!(global_timer_interrupt_status, GlobalTimerInterruptStatusRegister, RW, u32);
-register_bit!(global_timer_interrupt_status, event_flag, 0);
-
-register!(private_timer_control, PrivateTimerControlRegister, RW, u32);
-register_bits!(private_timer_control, sbzp, u32, 16, 31);
-register_bits!(private_timer_control, prescaler, u8, 8, 15);
-register_bits!(private_timer_control, unk_sbzp, u8, 3, 7);
-register_bit!(private_timer_control, irq_enable, 2);
-register_bit!(private_timer_control, auto_reload, 1);
-register_bit!(private_timer_control, timer_enable, 0);
-
-register!(private_timer_interrupt_status, PrivateTimerInterruptStatusRegister, RW, u32);
-register_bits!(private_timer_interrupt_status, unk_sbzp, u32, 1, 31);
-
-register!(watchdog_control, WatchdogControlRegister, RW, u32);
-register_bits!(watchdog_control, prescaler, u8, 8, 15);
-register_bit!(watchdog_control, watchdog_mode, 3);
-register_bit!(watchdog_control, it_enable, 2);
-register_bit!(watchdog_control, auto_reload, 1);
-register_bit!(watchdog_control, watchdog_enable, 0);
-
-register!(watchdog_interrupt_status, WatchdogInterruptStatusRegister, RW, u32);
-register_bit!(watchdog_interrupt_status, event_flag, 0);
-
-register!(watchdog_reset_status, WatchdogResetStatusRegister, RW, u32);
-register_bit!(watchdog_reset_status, reset_flag, 0);
-
-register!(icddcr, ICDDCR, RW, u32);
-register_bit!(icddcr, enable_non_secure, 1);
-register_bit!(icddcr, enable_secure, 0);
-
-register!(icdictr, ICDICTR, RO, u32);
-register_bits!(icdictr, lspi, u8, 11, 15);
-register_bit!(icdictr, security_extn, 10);
-register_bits!(icdictr, sbz, u8, 8, 9);
-register_bits!(icdictr, cpu_number, u8, 5, 7);
-register_bits!(icdictr, it_lines_number, u8, 0, 4);
-
-register!(icdiidr, ICDIIDR, RO, u32);
-register_bits!(icdiidr, implementation_version, u8, 24, 31);
-register_bits!(icdiidr, revision_number, u32, 12, 23);
-register_bits!(icdiidr, implementer, u32, 0, 11);
-
-register!(ppi_status, PpiStatus, RO, u32);
-register_bits!(ppi_status, ppi_status, u8, 11, 15);
-register_bits!(ppi_status, sbz, u32, 0, 10);
-
-register!(icdsgir, ICDSGIR, RW, u32);
-register_bits!(icdsgir, target_list_filter, u8, 24, 25);
-register_bits!(icdsgir, cpu_target_list, u8, 16, 23);
-register_bit!(icdsgir, satt, 15);
-register_bits!(icdsgir, sbz, u32, 4, 14);
-register_bits!(icdsgir, sgiintid, u8, 0, 3);
-
--- a/libboard_zynq/src/slcr.rs
+++ b/libboard_zynq/src/slcr.rs
@ -132,7 +132,7 @@ pub struct RegisterBlock {
    pub can_rst_ctrl: RW<u32>,
    pub i2c_rst_ctrl: RW<u32>,
    pub uart_rst_ctrl: UartRstCtrl,
-    pub gpio_rst_ctrl: GpioRstCtrl,
+    pub gpio_rst_ctrl: RW<u32>,
    pub lqspi_rst_ctrl: LqspiRstCtrl,
    pub smc_rst_ctrl: RW<u32>,
    pub ocm_rst_ctrl: RW<u32>,
@ -531,20 +531,6 @@ impl UartRstCtrl {
    }
 }

-register!(gpio_rst_ctrl, GpioRstCtrl, RW, u32);
-register_bit!(gpio_rst_ctrl, gpio_cpu1x_rst, 0);
-register_at!(GpioRstCtrl, 0xF800022C, new);
-impl GpioRstCtrl {
-    pub fn reset_gpio(&mut self) {
-        self.modify(|_, w|
-            w.gpio_cpu1x_rst(true)
-        );
-        self.modify(|_, w|
-            w.gpio_cpu1x_rst(false)
-        );
-    }
-}
-
 register!(lqspi_clk_ctrl, LqspiClkCtrl, RW, u32);
 register_bit!(lqspi_clk_ctrl, clkact, 0);
 register_bits_typed!(lqspi_clk_ctrl, src_sel, u8, PllSource, 4, 5);
--- a/libboard_zynq/src/timer/global.rs
+++ b/libboard_zynq/src/timer/global.rs
@ -138,15 +138,6 @@ where
    }
 }

-impl<U: PartialOrd> CountDown<U>
-where
-    GlobalTimer: TimeSource<U>,
-{
-    pub fn waiting(&self) -> bool {
-        self.timer.now() <= self.timeout
-    }
-}
-
 /// embedded-hal sync API
 impl embedded_hal::blocking::delay::DelayMs<u64> for GlobalTimer {
    fn delay_ms(&mut self, ms: u64) {
--- a/libcortex_a9/Cargo.toml
+++ b/libcortex_a9/Cargo.toml
@ -7,7 +7,6 @@ edition = "2018"
 [features]
 target_zc706 = []
 target_cora_z7_10 = []
-power_saving = []
 default = ["target_zc706"]

 [dependencies]
--- a/libcortex_a9/src/asm.rs
+++ b/libcortex_a9/src/asm.rs
@ -33,44 +33,3 @@ pub fn dsb() {
 pub fn isb() {
    unsafe { llvm_asm!("isb" :::: "volatile") }
 }
-
-/// Enable IRQ
-#[inline]
-pub unsafe fn enable_irq() {
-    llvm_asm!("cpsie i":::: "volatile");
-}
-
-/// Disable IRQ, return if IRQ was originally enabled.
-#[inline]
-pub unsafe fn enter_critical() -> bool {
-    let mut cpsr: u32;
-    llvm_asm!(
-        "mrs $0, cpsr
-         cpsid i"
-         : "=r"(cpsr) ::: "volatile");
-    (cpsr & (1 << 7)) == 0
-}
-
-#[inline]
-pub unsafe fn exit_critical(enable: bool) {
-    // https://stackoverflow.com/questions/40019929/temporarily-disable-interrupts-on-arm
-    let mask: u32 = if enable {
-        1 << 7
-    } else {
-        0
-    };
-    llvm_asm!(
-        "mrs r1, cpsr
-         bic r1, r1, $0
-         msr cpsr_c, r1"
-         :: "r"(mask) : "r1");
-}
-
-/// Exiting IRQ
-#[inline]
-pub unsafe fn exit_irq() {
-    llvm_asm!("
-        mrs r0, SPSR
-        msr CPSR, r0
-        " ::: "r0");
-}
--- a/libcortex_a9/src/lib.rs
+++ b/libcortex_a9/src/lib.rs
@ -1,7 +1,6 @@
 #![no_std]
 #![feature(llvm_asm, global_asm)]
 #![feature(never_type)]
-#![feature(const_fn)]

 extern crate alloc;

@ -11,26 +10,9 @@ pub mod cache;
 pub mod mmu;
 pub mod mutex;
 pub mod sync_channel;
-pub mod semaphore;
 mod uncached;
 mod fpu;
 pub use uncached::UncachedSlice;
 pub use fpu::enable_fpu;

 global_asm!(include_str!("exceptions.s"));
-
-#[inline]
-pub fn spin_lock_yield() {
-    #[cfg(feature = "power_saving")]
-    asm::wfe();
-}
-
-#[inline]
-pub fn notify_spin_lock() {
-    #[cfg(feature = "power_saving")]
-    {
-        asm::dsb();
-        asm::sev();
-    }
-}
-
--- a/libcortex_a9/src/mmu.rs
+++ b/libcortex_a9/src/mmu.rs
@ -338,7 +338,7 @@ impl L1Table {
        /* 0xfff00000 - 0xffffffff (256K OCM when mapped to high address space) */
        self.direct_mapped_section(0xfff, L1Section {
            global: true,
-            shareable: true,
+            shareable: false,
            access: AccessPermissions::FullAccess,
            tex: 0b100,
            domain: 0,
--- a/libcortex_a9/src/mutex.rs
+++ b/libcortex_a9/src/mutex.rs
@ -1,10 +1,20 @@
 use core::ops::{Deref, DerefMut};
 use core::sync::atomic::{AtomicU32, Ordering};
 use core::cell::UnsafeCell;
-use super::{
-    spin_lock_yield, notify_spin_lock,
-    asm::{dmb, enter_critical, exit_critical}
-};
+use super::asm::*;
+
+/// [Power-saving features](http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dht0008a/ch01s03s02.html)
+#[inline]
+fn wait_for_update() {
+    wfe();
+}
+
+/// [Power-saving features](http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dht0008a/ch01s03s02.html)
+#[inline]
+fn signal_update() {
+    dsb();
+    sev();
+}

 const LOCKED: u32 = 1;
 const UNLOCKED: u32 = 0;
@ -31,26 +41,19 @@ impl<T> Mutex<T> {

    /// Lock the Mutex, blocks when already locked
    pub fn lock(&self) -> MutexGuard<T> {
-        let mut irq = unsafe { enter_critical() };
        while self.locked.compare_and_swap(UNLOCKED, LOCKED, Ordering::Acquire) != UNLOCKED {
-            unsafe {
-                exit_critical(irq);
-                spin_lock_yield();
-                irq = enter_critical();
-            }
+            wait_for_update();
        }
        dmb();
-        MutexGuard { mutex: self, irq }
+        MutexGuard { mutex: self }
    }

    pub fn try_lock(&self) -> Option<MutexGuard<T>> {
-        let irq = unsafe { enter_critical() };
        if self.locked.compare_and_swap(UNLOCKED, LOCKED, Ordering::Acquire) != UNLOCKED {
-            unsafe { exit_critical(irq) };
            None
        } else {
            dmb();
-            Some(MutexGuard { mutex: self, irq })
+            Some(MutexGuard { mutex: self })
        }
    }

@ -58,7 +61,7 @@ impl<T> Mutex<T> {
        dmb();
        self.locked.store(UNLOCKED, Ordering::Release);

-        notify_spin_lock();
+        signal_update();
    }
 }

@ -66,7 +69,6 @@ impl<T> Mutex<T> {
 /// `Deref`/`DerefMutx`
 pub struct MutexGuard<'a, T> {
    mutex: &'a Mutex<T>,
-    irq: bool,
 }

 impl<'a, T> Deref for MutexGuard<'a, T> {
@ -86,6 +88,5 @@ impl<'a, T> DerefMut for MutexGuard<'a, T> {
 impl<'a, T> Drop for MutexGuard<'a, T> {
    fn drop(&mut self) {
        self.mutex.unlock();
-        unsafe { exit_critical(self.irq) };
    }
 }
--- a/libcortex_a9/src/semaphore.rs
+++ b/libcortex_a9/src/semaphore.rs
@ -1,71 +0,0 @@
-use super::{spin_lock_yield, notify_spin_lock};
-use core::{
-    task::{Context, Poll},
-    pin::Pin,
-    future::Future,
-    sync::atomic::{AtomicI32, Ordering}
-};
-
-pub struct Semaphore {
-    value: AtomicI32,
-    max: i32
-}
-
-impl Semaphore {
-    pub fn new(value: i32, max: i32) -> Self {
-        Semaphore { value: AtomicI32::new(value), max}
-    }
-
-    pub fn try_wait(&self) -> Option<()> {
-        loop {
-            let value = self.value.load(Ordering::Relaxed);
-            if value > 0 {
-                if self.value.compare_and_swap(value, value - 1, Ordering::SeqCst) == value {
-                    return Some(());
-                }
-            } else {
-                return None;
-            }
-        }
-    }
-
-    pub fn wait(&self) {
-        while self.try_wait().is_none() {
-            spin_lock_yield();
-        }
-    }
-
-    pub async fn async_wait(&self) {
-        struct Fut<'a>(&'a Semaphore);
-
-        impl Future for Fut<'_> {
-            type Output = ();
-            fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-                match self.0.try_wait() {
-                    Some(_) => Poll::Ready(()),
-                    None => {
-                        cx.waker().wake_by_ref();
-                        Poll::Pending
-                    }
-                }
-            }
-        }
-
-        Fut(&self).await
-    }
-
-    pub fn signal(&self) {
-        loop {
-            let value = self.value.load(Ordering::Relaxed);
-            if value < self.max {
-                if self.value.compare_and_swap(value, value + 1, Ordering::SeqCst) == value {
-                    notify_spin_lock();
-                    return;
-                }
-            } else {
-                return;
-            }
-        }
-    }
-}
-
--- a/libcortex_a9/src/sync_channel.rs
+++ b/libcortex_a9/src/sync_channel.rs
@ -1,73 +1,115 @@
 use core::{
-    pin::Pin,
    future::Future,
-    ptr::drop_in_place,
-    sync::atomic::{AtomicPtr, AtomicUsize, Ordering},
+    pin::Pin,
+    ptr::null_mut,
+    sync::atomic::{AtomicPtr, Ordering},
    task::{Context, Poll},
 };
-use alloc::boxed::Box;
-use super::{spin_lock_yield, notify_spin_lock};
+use alloc::{
+    boxed::Box,
+    sync::Arc,
+    vec::Vec,
+};
+use super::asm::*;

-pub struct Sender<'a, T> where T: Clone {
-    list: &'a [AtomicPtr<T>],
-    write: &'a AtomicUsize,
-    read: &'a AtomicUsize,
+
+type Channel<T> = Vec<AtomicPtr<T>>;
+
+/// Create a bounded channel
+///
+/// Returns `(tx, rx)` where one should be used one the local core,
+/// and the other is to be shared with another core.
+pub fn sync_channel<T>(bound: usize) -> (Sender<T>, Receiver<T>) {
+    // allow for bound=0
+    let len = bound + 1;
+    let mut channel = Vec::with_capacity(len);
+    for _ in 0..len {
+        channel.push(AtomicPtr::default());
    }

-pub struct Receiver<'a, T> where T: Clone {
-    list: &'a [AtomicPtr<T>],
-    write: &'a AtomicUsize,
-    read: &'a AtomicUsize,
+    let channel = Arc::new(channel);
+    let sender = Sender {
+        channel: channel.clone(),
+        pos: 0,
+    };
+    let receiver = Receiver {
+        channel: channel,
+        pos: 0,
+    };
+    (sender, receiver)
 }

-impl<'a, T> Sender<'a, T> where T: Clone {
-    pub const fn new(list: &'static [AtomicPtr<T>], write: &'static AtomicUsize, read: &'static AtomicUsize) -> Self {
-        Sender {list, write, read}
-    }
-
-    pub fn try_send<B: Into<Box<T>>>(&mut self, content: B) -> Result<(), B> {
-        let write = self.write.load(Ordering::Relaxed);
-        if (write + 1) % self.list.len() == self.read.load(Ordering::Acquire) {
-            Err(content)
-        } else {
-            let ptr = Box::into_raw(content.into());
-            let entry = &self.list[write];
-            let prev = entry.swap(ptr, Ordering::Relaxed);
-            // we allow other end get it first
-            self.write.store((write + 1) % self.list.len(), Ordering::Release);
-            notify_spin_lock();
-            if !prev.is_null() {
-                unsafe {
-                    drop_in_place(prev);
-                }
-            }
-            Ok(())
-        }
+/// Sending half of a channel
+pub struct Sender<T> {
+    channel: Arc<Channel<T>>,
+    pos: usize,
 }

+impl<T> Sender<T> {
+    /// Blocking send
    pub fn send<B: Into<Box<T>>>(&mut self, content: B) {
-        let mut content = content;
-        while let Err(back) = self.try_send(content) {
-            content = back;
-            spin_lock_yield();
+        let ptr = Box::into_raw(content.into());
+        let entry = &self.channel[self.pos];
+        // try to write the new pointer if the current pointer is
+        // NULL, retrying while it is not NULL
+        while entry.compare_and_swap(null_mut(), ptr, Ordering::Acquire) != null_mut() {
+            // power-saving
+            wfe();
+        }
+        dsb();
+        // wake power-saving receivers
+        sev();
+
+        // advance
+        self.pos += 1;
+        // wrap
+        if self.pos >= self.channel.len() {
+            self.pos = 0;
+        }
+    }
+
+    /// Non-blocking send, handing you back ownership of the content on **failure**
+    pub fn try_send<B: Into<Box<T>>>(&mut self, content: B) -> Option<Box<T>> {
+        let ptr = Box::into_raw(content.into());
+        let entry = &self.channel[self.pos];
+        // try to write the new pointer if the current pointer is
+        // NULL
+        if entry.compare_and_swap(null_mut(), ptr, Ordering::Acquire) == null_mut() {
+            dsb();
+            // wake power-saving receivers
+            sev();
+
+            // advance
+            self.pos += 1;
+            // wrap
+            if self.pos >= self.channel.len() {
+                self.pos = 0;
+            }
+
+            // success
+            None
+        } else {
+            let content = unsafe { Box::from_raw(ptr) };
+            // failure
+            Some(content)
        }
    }

    pub async fn async_send<B: Into<Box<T>>>(&mut self, content: B) {
-        struct Send<'a, 'b, T> where T: Clone, 'b: 'a {
-            sender: &'a mut Sender<'b, T>,
-            content: Result<(), Box<T>>,
+        struct Send<'a, T> {
+            sender: &'a mut Sender<T>,
+            content: Option<Box<T>>,
        }

-        impl<T> Future for Send<'_, '_, T> where T: Clone {
+        impl<T> Future for Send<'_, T> {
            type Output = ();

            fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-                match core::mem::replace(&mut self.content, Ok(())) {
-                    Err(content) => {
-                        if let Err(content) = self.sender.try_send(content) {
+                match self.content.take() {
+                    Some(content) => {
+                        if let Some(content) = self.sender.try_send(content) {
                            // failure
-                            self.content = Err(content);
+                            self.content = Some(content);
                            cx.waker().wake_by_ref();
                            Poll::Pending
                        } else {
@ -75,80 +117,93 @@ impl<'a, T> Sender<'a, T> where T: Clone {
                            Poll::Ready(())
                        }
                    }
-                    Ok(_) => panic!("Send future polled after success"),
+                    None => panic!("Send future polled after success"),
                }
            }
        }

        Send {
            sender: self,
-            content: Err(content.into()),
+            content: Some(content.into()),
        }.await
    }
-
-    /// free all items in the queue. It is the user's responsibility to
-    /// ensure no reader is trying to copy the data.
-    pub unsafe fn drop_elements(&mut self) {
-        for v in self.list.iter() {
-            let original = v.swap(core::ptr::null_mut(), Ordering::Relaxed);
-            if !original.is_null() {
-                drop_in_place(original);
-            }
-        }
 }

-    /// Reset the `sync_channel`, *forget* all items in the queue. Affects both the sender and
-    /// receiver.
-    pub unsafe fn reset(&mut self) {
-        self.write.store(0, Ordering::Relaxed);
-        self.read.store(0, Ordering::Relaxed);
-        for v in self.list.iter() {
-            v.store(core::ptr::null_mut(), Ordering::Relaxed);
-        }
-    }
+
+
+
+/// Receiving half of a channel
+pub struct Receiver<T> {
+    channel: Arc<Channel<T>>,
+    pos: usize,
 }

-impl<'a, T> Receiver<'a, T> where T: Clone {
-    pub const fn new(list: &'static [AtomicPtr<T>], write: &'static AtomicUsize, read: &'static AtomicUsize) -> Self {
-        Receiver {list, write, read}
-    }
+impl<T> Receiver<T> {
+    /// Blocking receive
+    pub fn recv(&mut self) -> Box<T> {
+        let entry = &self.channel[self.pos];

-    pub fn try_recv(&mut self) -> Result<T, ()> {
-        let read = self.read.load(Ordering::Relaxed);
-        if read == self.write.load(Ordering::Acquire) {
-            Err(())
-        } else {
-            let entry = &self.list[read];
-            let data = unsafe {
-                // we cannot deallocate the box
-                Box::leak(Box::from_raw(entry.load(Ordering::Relaxed)))
-            };
-            let result = data.clone();
-            self.read.store((read + 1) % self.list.len(), Ordering::Release);
-            notify_spin_lock();
-            Ok(result)
-        }
-    }
-
-    pub fn recv(&mut self) -> T {
        loop {
-            if let Ok(data) = self.try_recv() {
-                return data;
+            dmb();
+            let ptr = entry.swap(null_mut(), Ordering::Release);
+            if ptr != null_mut() {
+                dsb();
+                // wake power-saving senders
+                sev();
+
+                let content = unsafe { Box::from_raw(ptr) };
+
+                // advance
+                self.pos += 1;
+                // wrap
+                if self.pos >= self.channel.len() {
+                    self.pos = 0;
                }
-            spin_lock_yield();
+
+                return content;
+            }
+
+            // power-saving
+            wfe();
        }
    }

-    pub async fn async_recv(&mut self) -> T {
-        struct Recv<'a, 'b, T> where T: Clone, 'b: 'a {
-            receiver: &'a mut Receiver<'b, T>,
+    /// Non-blocking receive
+    pub fn try_recv(&mut self) -> Option<Box<T>> {
+        let entry = &self.channel[self.pos];
+
+        dmb();
+        let ptr = entry.swap(null_mut(), Ordering::Release);
+        if ptr != null_mut() {
+            dsb();
+            // wake power-saving senders
+            sev();
+
+            let content = unsafe { Box::from_raw(ptr) };
+
+            // advance
+            self.pos += 1;
+            // wrap
+            if self.pos >= self.channel.len() {
+                self.pos = 0;
            }

-        impl<T> Future for Recv<'_, '_, T> where T: Clone {
-            type Output = T;
+            Some(content)
+        } else {
+            None
+        }
+    }
+
+    pub async fn async_recv(&mut self) -> Box<T> {
+        struct Recv<'a, T> {
+            receiver: &'a mut Receiver<T>,
+        }
+
+        impl<T> Future for Recv<'_, T> {
+            type Output = Box<T>;

            fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-                if let Ok(content) = self.receiver.try_recv() {
+                if let Some(content) = self.receiver.try_recv() {
                    Poll::Ready(content)
                } else {
                    cx.waker().wake_by_ref();
@ -163,26 +218,10 @@ impl<'a, T> Receiver<'a, T> where T: Clone {
    }
 }

-impl<'a, T> Iterator for Receiver<'a, T> where T: Clone {
-    type Item = T;
+impl<T> Iterator for Receiver<T> {
+    type Item = Box<T>;

    fn next(&mut self) -> Option<Self::Item> {
        Some(self.recv())
    }
 }
-
-#[macro_export]
-/// Macro for initializing the sync_channel with static buffer and indexes.
-/// Note that this requires `#![feature(const_in_array_repeat_expressions)]`
-macro_rules! sync_channel {
-    ($t: ty, $cap: expr) => {
-        {
-            use core::sync::atomic::{AtomicUsize, AtomicPtr};
-            use $crate::sync_channel::{Sender, Receiver};
-            static LIST: [AtomicPtr<$t>; $cap + 1] = [AtomicPtr::new(core::ptr::null_mut()); $cap + 1];
-            static WRITE: AtomicUsize = AtomicUsize::new(0);
-            static READ: AtomicUsize = AtomicUsize::new(0);
-            (Sender::new(&LIST, &WRITE, &READ), Receiver::new(&LIST, &WRITE, &READ))
-        }
-    };
-}
--- a/libsupport_zynq/Cargo.toml
+++ b/libsupport_zynq/Cargo.toml
@ -9,10 +9,8 @@ edition = "2018"
 target_zc706 = ["libboard_zynq/target_zc706"]
 target_cora_z7_10 = ["libboard_zynq/target_cora_z7_10"]
 panic_handler = []
-dummy_irq_handler = []
-alloc_core = []

-default = ["panic_handler", "dummy_irq_handler"]
+default = ["panic_handler"]

 [dependencies]
 r0 = "1"
--- a/libsupport_zynq/src/abort.rs
+++ b/libsupport_zynq/src/abort.rs
@ -53,7 +53,6 @@ pub unsafe extern "C" fn ReservedException() {
 #[link_section = ".text.boot"]
 #[no_mangle]
 #[naked]
-#[cfg(feature = "dummy_irq_handler")]
 pub unsafe extern "C" fn IRQ() {
    stdio::drop_uart();
    println!("IRQ");
--- a/libsupport_zynq/src/boot.rs
+++ b/libsupport_zynq/src/boot.rs
@ -4,7 +4,7 @@ use libregister::{
    VolatileCell,
    RegisterR, RegisterW, RegisterRW,
 };
-use libcortex_a9::{asm, regs::*, cache, mmu, spin_lock_yield, notify_spin_lock};
+use libcortex_a9::{asm, regs::*, cache, mmu};
 use libboard_zynq::{slcr, mpcore};

 extern "C" {
@ -29,7 +29,7 @@ pub unsafe extern "C" fn Reset() -> ! {
        }
        1 => {
            while !CORE1_ENABLED.get() {
-                spin_lock_yield();
+                asm::wfe();
            }
            SP.write(&mut __stack1_start as *mut _ as u32);
            boot_core1();
@ -57,7 +57,6 @@ unsafe fn boot_core0() -> ! {
        asm::dmb();
        asm::dsb();

-        asm::enable_irq();
        main_core0();
        panic!("return from main");
    });
@ -78,7 +77,6 @@ unsafe fn boot_core1() -> ! {
        asm::dmb();
        asm::dsb();

-        asm::enable_irq();
        main_core1();
        panic!("return from main_core1");
    });
@ -144,7 +142,6 @@ impl Core1 {
            slcr.a9_cpu_rst_ctrl.modify(|_, w| w.a9_rst1(false));
            slcr.a9_cpu_rst_ctrl.modify(|_, w| w.a9_clkstop1(false));
        });
-        notify_spin_lock();

        Core1 {}
    }
@ -152,8 +149,6 @@ impl Core1 {
    pub fn disable(&self) {
        unsafe {
            CORE1_ENABLED.set(false);
-            cache::dccmvac(&CORE1_ENABLED  as *const _ as usize);
-            asm::dsb();
        }
        self.restart();
    }
--- a/libsupport_zynq/src/ram.rs
+++ b/libsupport_zynq/src/ram.rs
@ -1,97 +1,55 @@
-use alloc::alloc::Layout;
 use core::alloc::GlobalAlloc;
 use core::ptr::NonNull;
-use libcortex_a9::{
-    mutex::Mutex,
-    regs::MPIDR
-};
-use libregister::RegisterR;
+use alloc::alloc::Layout;
 use linked_list_allocator::Heap;
-#[cfg(not(feature = "alloc_core"))]
+use libcortex_a9::mutex::Mutex;
 use libboard_zynq::ddr::DdrRam;

 #[global_allocator]
-static ALLOCATOR: CortexA9Alloc = CortexA9Alloc(
-    Mutex::new(Heap::empty()),
-    Mutex::new(Heap::empty()),
-);
+static ALLOCATOR: CortexA9Alloc = CortexA9Alloc(Mutex::new(Heap::empty()));

-struct CortexA9Alloc(Mutex<Heap>, Mutex<Heap>);
+/// LockedHeap doesn't lock properly
+struct CortexA9Alloc(Mutex<Heap>);

 unsafe impl Sync for CortexA9Alloc {}

 unsafe impl GlobalAlloc for CortexA9Alloc {
    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        if cfg!(not(feature = "alloc_core")) || MPIDR.read().cpu_id() == 0 {
-            &self.0
-        } else {
-            &self.1
-        }
-        .lock()
+        self.0.lock()
            .allocate_first_fit(layout)
            .ok()
            .map_or(0 as *mut u8, |allocation| allocation.as_ptr())
    }

    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
-        if cfg!(not(feature = "alloc_core")) || MPIDR.read().cpu_id() == 0 {
-            &self.0
-        } else {
-            &self.1
-        }
-        .lock()
+        self.0.lock()
            .deallocate(NonNull::new_unchecked(ptr), layout)
    }
 }

-#[cfg(not(feature = "alloc_core"))]
 pub fn init_alloc_ddr(ddr: &mut DdrRam) {
    unsafe {
-        ALLOCATOR
-            .0
-            .lock()
+        ALLOCATOR.0.lock()
            .init(ddr.ptr::<u8>() as usize, ddr.size());
    }
 }

 extern "C" {
-    static __heap0_start: usize;
-    static __heap0_end: usize;
-    #[cfg(feature = "alloc_core")]
-    static __heap1_start: usize;
-    #[cfg(feature = "alloc_core")]
-    static __heap1_end: usize;
+    static __heap_start: usize;
+    static __heap_end: usize;
 }

-pub fn init_alloc_core0() {
+pub fn init_alloc_linker() {
    unsafe {
-        let start = &__heap0_start as *const usize as usize;
-        let end = &__heap0_end as *const usize as usize;
-        ALLOCATOR.0.lock().init(start, end - start);
+        let start = &__heap_start as *const usize as usize;
+        let end = &__heap_end as *const usize as usize;
+        ALLOCATOR.0.lock()
+            .init(start, end - start);
    }
 }

-#[cfg(feature = "alloc_core")]
-pub fn init_alloc_core1() {
-    unsafe {
-        let start = &__heap1_start as *const usize as usize;
-        let end = &__heap1_end as *const usize as usize;
-        ALLOCATOR.1.lock().init(start, end - start);
-    }
-}

 #[alloc_error_handler]
-fn alloc_error(layout: core::alloc::Layout) -> ! {
-    let id = MPIDR.read().cpu_id();
-    let used = if cfg!(not(feature = "alloc_core")) || id == 0 {
-        ALLOCATOR.0.lock().used()
-    } else {
-        ALLOCATOR.1.lock().used()
-    };
-    panic!(
-        "Core {} alloc_error, layout: {:?}, used memory: {}",
-        id,
-        layout,
-        used
-    );
+fn alloc_error(_: core::alloc::Layout) -> ! {
+    panic!("alloc_error")
 }
--- a/shell.nix
+++ b/shell.nix
@ -19,6 +19,6 @@ stdenv.mkDerivation {
  XARGO_RUST_SRC = "${rustcSrc}/src";

  shellHook = ''
-    echo "Run 'cargo xbuild --release -p experiments' to build."
+    echo "Run 'cargo xbuild --release' to build."
  '';
 }