libasync, libboard_zynq: add block_async glue, make GlobalTimer sharable

Cargo.lock

@@ -38,6 +38,7 @@ dependencies = [
 name = "experiments"
 version = "0.0.0"
 dependencies = [
+ "embedded-hal 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "libasync 0.0.0",
  "libboard_zynq 0.0.0",
  "libcortex_a9 0.0.0",
@@ -50,8 +51,10 @@ dependencies = [
 name = "libasync"
 version = "0.0.0"
 dependencies = [
+ "embedded-hal 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "libboard_zynq 0.0.0",
  "libcortex_a9 0.0.0",
+ "nb 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "pin-utils 0.1.0-alpha.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "smoltcp 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -66,6 +69,7 @@ dependencies = [
  "libregister 0.0.0",
  "nb 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "smoltcp 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "volatile-register 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 

experiments/Cargo.toml

@@ -12,6 +12,7 @@ default = ["target_zc706"]
 
 [dependencies]
 log = "0.4"
+embedded-hal = "0.2"
 libregister = { path = "../libregister" }
 libcortex_a9 = { path = "../libcortex_a9" }
 libboard_zynq = { path = "../libboard_zynq" }

experiments/src/main.rs

@@ -6,6 +6,8 @@ extern crate alloc;
 use core::{mem::transmute, task::Poll};
 use alloc::{borrow::ToOwned, collections::BTreeMap, format};
 use log::info;
+use embedded_hal::timer::CountDown;
+use libregister::RegisterR;
 use libcortex_a9::{mutex::Mutex, sync_channel::{self, sync_channel}};
 use libboard_zynq::{
     print, println,
@@ -18,12 +20,13 @@ use libboard_zynq::{
         socket::SocketSet,
         socket::{TcpSocket, TcpSocketBuffer},
     },
+    time::Milliseconds,
 };
 use libsupport_zynq::{
     ram, alloc::{vec, vec::Vec},
     boot,
 };
-use libasync::{smoltcp::{Sockets, TcpStream}, task};
+use libasync::{delay, smoltcp::{Sockets, TcpStream}, task};
 
 mod ps7_init;
 
@@ -39,10 +42,7 @@ pub fn main_core0() {
     libsupport_zynq::logger::init().unwrap();
     log::set_max_level(log::LevelFilter::Trace);
 
-    {
-        use libregister::RegisterR;
     info!("Boot mode: {:?}", zynq::slcr::RegisterBlock::new().boot_mode.read().boot_mode_pins());
-    }
 
     #[cfg(feature = "target_zc706")]
     const CPU_FREQ: u32 = 800_000_000;
@@ -72,6 +72,8 @@ pub fn main_core0() {
     }
     let mut flash = flash.stop();
 
+    let timer = libboard_zynq::timer::GlobalTimer::new();
+
     let mut ddr = zynq::ddr::DdrRam::new();
     #[cfg(not(feature = "target_zc706"))]
     ddr.memtest();
@@ -262,10 +264,16 @@ pub fn main_core0() {
         }
     });
 
-    let mut time = 0u32;
+    let mut countdown = timer.countdown();
+    task::spawn(async move {
+        loop {
+            delay(&mut countdown, Milliseconds(1000)).await;
+            println!("time: {} ms", timer.get_time().0);
+        }
+    });
+
     Sockets::run(&mut iface, || {
-        time += 1;
-        Instant::from_millis(time)
+        Instant::from_millis(timer.get_time().0 as i64)
     })
 }
 

libasync/Cargo.toml

@@ -8,6 +8,8 @@ edition = "2018"
 [dependencies]
 #futures = { version = "0.3", default-features = false }
 pin-utils = "0.1.0-alpha.4"
+embedded-hal = "0.2"
+nb = "0.1"
 libcortex_a9 = { path = "../libcortex_a9" }
 
 [dependencies.smoltcp]

libasync/src/lib.rs

@@ -4,5 +4,33 @@ extern crate alloc;
 
 pub mod task;
 pub mod executor;
+mod delay;
+pub use delay::delay;
 
 pub mod smoltcp;
+
+/// Reexport for macro use
+pub use nb;
+
+/// The `nb` crate's `block!` macro adapted for async fns
+///
+/// Call `.await` on the result!
+#[macro_export]
+macro_rules! block_async {
+    ($e:expr) => {
+        async {
+            loop {
+                #[allow(unreachable_patterns)]
+                match $e {
+                    Err($crate::nb::Error::Other(e)) => {
+                        #[allow(unreachable_code)]
+                        break Err(e)
+                    },
+                    Err($crate::nb::Error::WouldBlock) =>
+                        $crate::task::r#yield().await,
+                    Ok(x) => break Ok(x),
+                }
+            }
+        }
+    }
+}

libboard_zynq/Cargo.toml

@@ -14,6 +14,7 @@ volatile-register = "0.2"
 bit_field = "0.10"
 embedded-hal = "0.2"
 nb = "0.1"
+void = { version = "1", default-features = false }
 libregister = { path = "../libregister" }
 libcortex_a9 = { path = "../libcortex_a9" }
 

libboard_zynq/src/lib.rs

@@ -15,3 +15,5 @@ pub mod ddr;
 pub mod mpcore;
 pub mod flash;
 pub mod dmac;
+pub mod time;
+pub mod timer;

libboard_zynq/src/mpcore.rs

@@ -18,6 +18,34 @@ pub struct RegisterBlock {
     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,
+    pub global_timer_control: GlobalTimerControl,
+    pub global_timer_interrupt_status: RW<u32>,
+    pub comparator_value0: ValueRegister,
+    pub comparator_value1: ValueRegister,
+    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);
@@ -59,3 +87,13 @@ impl ScuInvalidate {
         );
     }
 }
+
+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, u16, 8, 15);
+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);

libboard_zynq/src/time.rs

@@ -0,0 +1,10 @@
+#[derive(Debug, Clone, PartialEq, PartialOrd)]
+pub struct Milliseconds(pub u64);
+
+impl core::ops::Add for Milliseconds {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        Milliseconds(self.0 + rhs.0)
+    }
+}

libboard_zynq/src/timer/global.rs

@@ -0,0 +1,99 @@
+use void::Void;
+use libregister::{RegisterR, RegisterW};
+use crate::{
+    clocks::Clocks,
+    mpcore,
+    time::Milliseconds,
+};
+
+/// "uptime"
+#[derive(Clone, Copy)]
+pub struct GlobalTimer {
+    regs: &'static mpcore::RegisterBlock,
+}
+
+impl GlobalTimer {
+    pub fn new() -> GlobalTimer {
+        let mut regs = mpcore::RegisterBlock::new();
+        Self::reset(&mut regs);
+        GlobalTimer { regs }
+    }
+
+    fn reset(regs: &mut mpcore::RegisterBlock) {
+        // Disable
+        regs.global_timer_control.write(
+            mpcore::GlobalTimerControl::zeroed()
+        );
+
+        // Reset counters
+        regs.global_timer_counter0.write(
+            mpcore::ValueRegister::zeroed()
+        );
+        regs.global_timer_counter1.write(
+            mpcore::ValueRegister::zeroed()
+        );
+
+        // Start
+        regs.global_timer_control.write(
+            mpcore::GlobalTimerControl::zeroed()
+                // maximum prescaler is still enough for millisecond
+                // precision while overflowing after centuries.
+                .prescaler(255)
+                .auto_increment_mode(true)
+                .timer_enable(true)
+        );
+    }
+
+    /// read the raw counter value
+    pub fn get_counter(&self) -> u64 {
+        loop {
+            let c1_pre = self.regs.global_timer_counter1.read().value();
+            let c0 = self.regs.global_timer_counter0.read().value();
+            let c1_post = self.regs.global_timer_counter1.read().value();
+
+            if c1_pre == c1_post {
+                return ((c1_pre as u64) << 32) | (c0 as u64);
+            }
+            // retry if c0 has wrapped while reading.
+        }
+    }
+
+    /// read and convert to time
+    pub fn get_time(&self) -> Milliseconds {
+        let prescaler = self.regs.global_timer_control.read().prescaler() as u64;
+        let clocks = Clocks::get();
+
+        Milliseconds(self.get_counter() * (prescaler + 1) / (clocks.cpu_3x2x() as u64 / 1000))
+    }
+
+    /// return a handle that has implements
+    /// `embedded_hal::timer::CountDown`
+    pub fn countdown(&self) -> CountDown {
+        CountDown {
+            timer: self.clone(),
+            timeout: Milliseconds(0),
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct CountDown {
+    timer: GlobalTimer,
+    timeout: Milliseconds,
+}
+
+impl embedded_hal::timer::CountDown for CountDown {
+    type Time = Milliseconds;
+
+    fn start<T: Into<Self::Time>>(&mut self, count: T) {
+        self.timeout = self.timer.get_time() + count.into();
+    }
+
+    fn wait(&mut self) -> nb::Result<(), Void> {
+        if self.timer.get_time() < self.timeout {
+            Err(nb::Error::WouldBlock)
+        } else {
+            Ok(())
+        }
+    }
+}

libboard_zynq/src/timer/mod.rs

@@ -0,0 +1,2 @@
+pub mod global;
+pub use global::GlobalTimer;

libboard_zynq/src/uart/mod.rs

@@ -1,4 +1,5 @@
 use core::fmt;
+use void::Void;
 
 use libregister::*;
 use super::slcr;
@@ -209,9 +210,9 @@ impl fmt::Write for Uart {
 
 /// embedded_hal async API
 impl embedded_hal::serial::Write<u8> for Uart {
-    type Error = ();
+    type Error = Void;
 
-    fn write(&mut self, b: u8) -> nb::Result<(), ()> {
+    fn write(&mut self, b: u8) -> nb::Result<(), Void> {
         if self.tx_fifo_full() {
             Err(nb::Error::WouldBlock)
         } else {
@@ -220,7 +221,7 @@ impl embedded_hal::serial::Write<u8> for Uart {
         }
     }
 
-    fn flush(&mut self) -> nb::Result<(), ()> {
+    fn flush(&mut self) -> nb::Result<(), Void> {
         if self.tx_fifo_empty() {
             Ok(())
         } else {