6 files changed, 560 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 069437317..31fe26476 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,6 +5,7 @@ members = [
     "embassy-traits",
     "embassy-nrf",
     "embassy-stm32f4",
+    "embassy-stm32l0",
     "embassy-nrf-examples",
     "embassy-stm32f4-examples",
     "embassy-macros",
diff --git a/embassy-stm32l0/Cargo.toml b/embassy-stm32l0/Cargo.toml
new file mode 100644
index 000000000..ad668b8d3
--- /dev/null
+++ b/embassy-stm32l0/Cargo.toml
@@ -0,0 +1,26 @@
+[package]
+name = "embassy-stm32l0"
+version = "0.1.0"
+authors = ["Michael Beaumont <[email protected]>"]
+edition = "2018"
+
+[features]
+defmt-trace = [ ]
+defmt-debug = [ ]
+defmt-info = [ ]
+defmt-warn = [ ]
+defmt-error = [ ]
+
+stm32l0x1 = ["stm32l0xx-hal/stm32l0x1"]
+stm32l0x2 = ["stm32l0xx-hal/stm32l0x2"]
+stm32l0x3 = ["stm32l0xx-hal/stm32l0x3"]
+
+[dependencies]
+embassy = { version = "0.1.0", path = "../embassy" }
+defmt = { version = "0.2.0", optional = true }
+log = { version = "0.4.11", optional = true }
+cortex-m-rt = "0.6.13"
+cortex-m = "0.7.1"
+embedded-hal = { version = "0.2.4" }
+embedded-dma = { version = "0.1.2" }
+stm32l0xx-hal = { version = "0.6.2", features = ["rt"], git = "https://github.com/stm32-rs/stm32l0xx-hal.git"}
diff --git a/embassy-stm32l0/src/exti.rs b/embassy-stm32l0/src/exti.rs
new file mode 100644
index 000000000..84c38ccc7
--- /dev/null
+++ b/embassy-stm32l0/src/exti.rs
@@ -0,0 +1,220 @@
+use core::future::Future;
+use core::mem;
+use core::pin::Pin;
+
+use embassy::interrupt::Interrupt;
+use embassy::traits::gpio::{WaitForFallingEdge, WaitForRisingEdge};
+use embassy::util::InterruptFuture;
+
+use crate::hal::{
+    exti::{Exti, ExtiLine, GpioLine, TriggerEdge},
+    gpio,
+    syscfg::SYSCFG,
+};
+use crate::interrupt;
+use crate::pac::EXTI;
+
+pub struct ExtiManager {
+    syscfg: SYSCFG,
+}
+
+impl<'a> ExtiManager {
+    pub fn new(_exti: Exti, syscfg: SYSCFG) -> Self {
+        Self { syscfg }
+    }
+
+    pub fn new_pin<T, I>(&'static mut self, pin: T, interrupt: I) -> ExtiPin<T, I>
+    where
+        T: PinWithInterrupt<Interrupt = I>,
+        I: Interrupt,
+    {
+        ExtiPin {
+            pin,
+            interrupt,
+            mgr: self,
+        }
+    }
+}
+
+pub struct ExtiPin<T, I> {
+    pin: T,
+    interrupt: I,
+    mgr: &'static mut ExtiManager,
+}
+
+impl<T: PinWithInterrupt<Interrupt = I> + 'static, I: Interrupt + 'static> WaitForRisingEdge
+    for ExtiPin<T, I>
+{
+    type Future<'a> = impl Future<Output = ()> + 'a;
+
+    fn wait_for_rising_edge<'a>(self: Pin<&'a mut Self>) -> Self::Future<'a> {
+        let s = unsafe { self.get_unchecked_mut() };
+
+        let line = s.pin.line();
+        Exti::unpend(line);
+
+        async move {
+            let exti: EXTI = unsafe { mem::transmute(()) };
+            let mut exti = Exti::new(exti);
+            let fut = InterruptFuture::new(&mut s.interrupt);
+
+            exti.listen_gpio(&mut s.mgr.syscfg, s.pin.port(), line, TriggerEdge::Rising);
+            fut.await;
+
+            Exti::unpend(line);
+        }
+    }
+}
+
+impl<T: PinWithInterrupt<Interrupt = I> + 'static, I: Interrupt + 'static> WaitForFallingEdge
+    for ExtiPin<T, I>
+{
+    type Future<'a> = impl Future<Output = ()> + 'a;
+
+    fn wait_for_falling_edge<'a>(self: Pin<&'a mut Self>) -> Self::Future<'a> {
+        let s = unsafe { self.get_unchecked_mut() };
+
+        let line = s.pin.line();
+        Exti::unpend(line);
+
+        async move {
+            let exti: EXTI = unsafe { mem::transmute(()) };
+            let mut exti = Exti::new(exti);
+            let fut = InterruptFuture::new(&mut s.interrupt);
+
+            exti.listen_gpio(&mut s.mgr.syscfg, s.pin.port(), line, TriggerEdge::Falling);
+            fut.await;
+
+            Exti::unpend(line);
+        }
+    }
+}
+
+mod private {
+    pub trait Sealed {}
+}
+
+pub trait PinWithInterrupt: private::Sealed {
+    type Interrupt;
+    fn port(&self) -> gpio::Port;
+    fn line(&self) -> GpioLine;
+}
+
+macro_rules! exti {
+    ($($PER:ident => ($set:ident, $pin:ident),)+) => {
+        $(
+            impl<T> private::Sealed for gpio::$set::$pin<T> {}
+            impl<T> PinWithInterrupt for gpio::$set::$pin<T> {
+                type Interrupt = interrupt::$PER;
+                fn port(&self) -> gpio::Port {
+                    self.port()
+                }
+                fn line(&self) -> GpioLine {
+                    GpioLine::from_raw_line(self.pin_number()).unwrap()
+                }
+            }
+        )+
+    }
+}
+
+exti! {
+    EXTI0_1 => (gpioa, PA0),
+    EXTI0_1 => (gpioa, PA1),
+    EXTI2_3 => (gpioa, PA2),
+    EXTI2_3 => (gpioa, PA3),
+    EXTI4_15 => (gpioa, PA4),
+    EXTI4_15 => (gpioa, PA5),
+    EXTI4_15 => (gpioa, PA6),
+    EXTI4_15 => (gpioa, PA7),
+    EXTI4_15 => (gpioa, PA8),
+    EXTI4_15 => (gpioa, PA9),
+    EXTI4_15 => (gpioa, PA10),
+    EXTI4_15 => (gpioa, PA11),
+    EXTI4_15 => (gpioa, PA12),
+    EXTI4_15 => (gpioa, PA13),
+    EXTI4_15 => (gpioa, PA14),
+    EXTI4_15 => (gpioa, PA15),
+}
+
+exti! {
+    EXTI0_1 => (gpiob, PB0),
+    EXTI0_1 => (gpiob, PB1),
+    EXTI2_3 => (gpiob, PB2),
+    EXTI2_3 => (gpiob, PB3),
+    EXTI4_15 => (gpiob, PB4),
+    EXTI4_15 => (gpiob, PB5),
+    EXTI4_15 => (gpiob, PB6),
+    EXTI4_15 => (gpiob, PB7),
+    EXTI4_15 => (gpiob, PB8),
+    EXTI4_15 => (gpiob, PB9),
+    EXTI4_15 => (gpiob, PB10),
+    EXTI4_15 => (gpiob, PB11),
+    EXTI4_15 => (gpiob, PB12),
+    EXTI4_15 => (gpiob, PB13),
+    EXTI4_15 => (gpiob, PB14),
+    EXTI4_15 => (gpiob, PB15),
+}
+
+exti! {
+    EXTI0_1 => (gpioc, PC0),
+    EXTI0_1 => (gpioc, PC1),
+    EXTI2_3 => (gpioc, PC2),
+    EXTI2_3 => (gpioc, PC3),
+    EXTI4_15 => (gpioc, PC4),
+    EXTI4_15 => (gpioc, PC5),
+    EXTI4_15 => (gpioc, PC6),
+    EXTI4_15 => (gpioc, PC7),
+    EXTI4_15 => (gpioc, PC8),
+    EXTI4_15 => (gpioc, PC9),
+    EXTI4_15 => (gpioc, PC10),
+    EXTI4_15 => (gpioc, PC11),
+    EXTI4_15 => (gpioc, PC12),
+    EXTI4_15 => (gpioc, PC13),
+    EXTI4_15 => (gpioc, PC14),
+    EXTI4_15 => (gpioc, PC15),
+}
+
+exti! {
+    EXTI0_1 => (gpiod, PD0),
+    EXTI0_1 => (gpiod, PD1),
+    EXTI2_3 => (gpiod, PD2),
+    EXTI2_3 => (gpiod, PD3),
+    EXTI4_15 => (gpiod, PD4),
+    EXTI4_15 => (gpiod, PD5),
+    EXTI4_15 => (gpiod, PD6),
+    EXTI4_15 => (gpiod, PD7),
+    EXTI4_15 => (gpiod, PD8),
+    EXTI4_15 => (gpiod, PD9),
+    EXTI4_15 => (gpiod, PD10),
+    EXTI4_15 => (gpiod, PD11),
+    EXTI4_15 => (gpiod, PD12),
+    EXTI4_15 => (gpiod, PD13),
+    EXTI4_15 => (gpiod, PD14),
+    EXTI4_15 => (gpiod, PD15),
+}
+
+exti! {
+    EXTI0_1 => (gpioe, PE0),
+    EXTI0_1 => (gpioe, PE1),
+    EXTI2_3 => (gpioe, PE2),
+    EXTI2_3 => (gpioe, PE3),
+    EXTI4_15 => (gpioe, PE4),
+    EXTI4_15 => (gpioe, PE5),
+    EXTI4_15 => (gpioe, PE6),
+    EXTI4_15 => (gpioe, PE7),
+    EXTI4_15 => (gpioe, PE8),
+    EXTI4_15 => (gpioe, PE9),
+    EXTI4_15 => (gpioe, PE10),
+    EXTI4_15 => (gpioe, PE11),
+    EXTI4_15 => (gpioe, PE12),
+    EXTI4_15 => (gpioe, PE13),
+    EXTI4_15 => (gpioe, PE14),
+    EXTI4_15 => (gpioe, PE15),
+}
+
+exti! {
+    EXTI0_1 => (gpioh, PH0),
+    EXTI0_1 => (gpioh, PH1),
+    EXTI4_15 => (gpioh, PH9),
+    EXTI4_15 => (gpioh, PH10),
+}
diff --git a/embassy-stm32l0/src/fmt.rs b/embassy-stm32l0/src/fmt.rs
new file mode 100644
index 000000000..1be1057a7
--- /dev/null
+++ b/embassy-stm32l0/src/fmt.rs
@@ -0,0 +1,119 @@
+#![macro_use]
+#![allow(clippy::module_inception)]
+
+#[cfg(all(feature = "defmt", feature = "log"))]
+compile_error!("You may not enable both `defmt` and `log` features.");
+
+pub use fmt::*;
+
+#[cfg(feature = "defmt")]
+mod fmt {
+    pub use defmt::{
+        assert, assert_eq, assert_ne, debug, debug_assert, debug_assert_eq, debug_assert_ne, error,
+        info, panic, todo, trace, unreachable, unwrap, warn,
+    };
+}
+
+#[cfg(feature = "log")]
+mod fmt {
+    pub use core::{
+        assert, assert_eq, assert_ne, debug_assert, debug_assert_eq, debug_assert_ne, panic, todo,
+        unreachable,
+    };
+    pub use log::{debug, error, info, trace, warn};
+}
+
+#[cfg(not(any(feature = "defmt", feature = "log")))]
+mod fmt {
+    #![macro_use]
+
+    pub use core::{
+        assert, assert_eq, assert_ne, debug_assert, debug_assert_eq, debug_assert_ne, panic, todo,
+        unreachable,
+    };
+
+    #[macro_export]
+    macro_rules! trace {
+        ($($msg:expr),+ $(,)?) => {
+            ()
+        };
+    }
+
+    #[macro_export]
+    macro_rules! debug {
+        ($($msg:expr),+ $(,)?) => {
+            ()
+        };
+    }
+
+    #[macro_export]
+    macro_rules! info {
+        ($($msg:expr),+ $(,)?) => {
+            ()
+        };
+    }
+
+    #[macro_export]
+    macro_rules! warn {
+        ($($msg:expr),+ $(,)?) => {
+            ()
+        };
+    }
+
+    #[macro_export]
+    macro_rules! error {
+        ($($msg:expr),+ $(,)?) => {
+            ()
+        };
+    }
+}
+
+#[cfg(not(feature = "defmt"))]
+#[macro_export]
+macro_rules! unwrap {
+    ($arg:expr) => {
+        match $crate::fmt::Try::into_result($arg) {
+            ::core::result::Result::Ok(t) => t,
+            ::core::result::Result::Err(e) => {
+                ::core::panic!("unwrap of `{}` failed: {:?}", ::core::stringify!($arg), e);
+            }
+        }
+    };
+    ($arg:expr, $($msg:expr),+ $(,)? ) => {
+        match $crate::fmt::Try::into_result($arg) {
+            ::core::result::Result::Ok(t) => t,
+            ::core::result::Result::Err(e) => {
+                ::core::panic!("unwrap of `{}` failed: {}: {:?}", ::core::stringify!($arg), ::core::format_args!($($msg,)*), e);
+            }
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub struct NoneError;
+
+pub trait Try {
+    type Ok;
+    type Error;
+    fn into_result(self) -> Result<Self::Ok, Self::Error>;
+}
+
+impl<T> Try for Option<T> {
+    type Ok = T;
+    type Error = NoneError;
+
+    #[inline]
+    fn into_result(self) -> Result<T, NoneError> {
+        self.ok_or(NoneError)
+    }
+}
+
+impl<T, E> Try for Result<T, E> {
+    type Ok = T;
+    type Error = E;
+
+    #[inline]
+    fn into_result(self) -> Self {
+        self
+    }
+}
diff --git a/embassy-stm32l0/src/interrupt.rs b/embassy-stm32l0/src/interrupt.rs
new file mode 100644
index 000000000..499f3f275
--- /dev/null
+++ b/embassy-stm32l0/src/interrupt.rs
@@ -0,0 +1,162 @@
+//! Interrupt management
+use crate::pac::NVIC_PRIO_BITS;
+
+// Re-exports
+pub use cortex_m::interrupt::{CriticalSection, Mutex};
+pub use embassy::interrupt::{declare, take, Interrupt};
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[repr(u8)]
+pub enum Priority {
+    Level0 = 0,
+    Level1 = 1,
+    Level2 = 2,
+    Level3 = 3,
+    Level4 = 4,
+    Level5 = 5,
+    Level6 = 6,
+    Level7 = 7,
+    Level8 = 8,
+    Level9 = 9,
+    Level10 = 10,
+    Level11 = 11,
+    Level12 = 12,
+    Level13 = 13,
+    Level14 = 14,
+    Level15 = 15,
+}
+
+impl From<u8> for Priority {
+    fn from(priority: u8) -> Self {
+        match priority >> (8 - NVIC_PRIO_BITS) {
+            0 => Self::Level0,
+            1 => Self::Level1,
+            2 => Self::Level2,
+            3 => Self::Level3,
+            4 => Self::Level4,
+            5 => Self::Level5,
+            6 => Self::Level6,
+            7 => Self::Level7,
+            8 => Self::Level8,
+            9 => Self::Level9,
+            10 => Self::Level10,
+            11 => Self::Level11,
+            12 => Self::Level12,
+            13 => Self::Level13,
+            14 => Self::Level14,
+            15 => Self::Level15,
+            _ => unreachable!(),
+        }
+    }
+}
+
+impl From<Priority> for u8 {
+    fn from(p: Priority) -> Self {
+        (p as u8) << (8 - NVIC_PRIO_BITS)
+    }
+}
+
+#[cfg(feature = "stm32l0x1")]
+mod irqs {
+    use super::*;
+    declare!(WWDG);
+    declare!(PVD);
+    declare!(RTC);
+    declare!(FLASH);
+    declare!(RCC);
+    declare!(EXTI0_1);
+    declare!(EXTI2_3);
+    declare!(EXTI4_15);
+    declare!(DMA1_CHANNEL1);
+    declare!(DMA1_CHANNEL2_3);
+    declare!(DMA1_CHANNEL4_7);
+    declare!(ADC_COMP);
+    declare!(LPTIM1);
+    declare!(USART4_USART5);
+    declare!(TIM2);
+    declare!(TIM3);
+    declare!(TIM6);
+    declare!(TIM7);
+    declare!(TIM21);
+    declare!(I2C3);
+    declare!(TIM22);
+    declare!(I2C1);
+    declare!(I2C2);
+    declare!(SPI1);
+    declare!(SPI2);
+    declare!(USART1);
+    declare!(USART2);
+    declare!(AES_RNG_LPUART1);
+}
+
+#[cfg(feature = "stm32l0x2")]
+mod irqs {
+    use super::*;
+    declare!(WWDG);
+    declare!(PVD);
+    declare!(RTC);
+    declare!(RCC);
+    declare!(EXTI0_1);
+    declare!(EXTI2_3);
+    declare!(EXTI4_15);
+    declare!(TSC);
+    declare!(DMA1_CHANNEL1);
+    declare!(DMA1_CHANNEL2_3);
+    declare!(DMA1_CHANNEL4_7);
+    declare!(ADC_COMP);
+    declare!(LPTIM1);
+    declare!(USART4_USART5);
+    declare!(TIM2);
+    declare!(TIM3);
+    declare!(TIM6_DAC);
+    declare!(TIM7);
+    declare!(TIM21);
+    declare!(I2C3);
+    declare!(TIM22);
+    declare!(I2C1);
+    declare!(I2C2);
+    declare!(SPI1);
+    declare!(SPI2);
+    declare!(USART1);
+    declare!(USART2);
+    declare!(AES_RNG_LPUART1);
+    declare!(USB);
+}
+
+#[cfg(feature = "stm32l0x3")]
+mod irqs {
+    use super::*;
+    declare!(WWDG);
+    declare!(PVD);
+    declare!(RTC);
+    declare!(RCC);
+    declare!(EXTI0_1);
+    declare!(EXTI2_3);
+    declare!(EXTI4_15);
+    declare!(TSC);
+    declare!(DMA1_CHANNEL1);
+    declare!(DMA1_CHANNEL2_3);
+    declare!(DMA1_CHANNEL4_7);
+    declare!(ADC_COMP);
+    declare!(LPTIM1);
+    declare!(USART4_USART5);
+    declare!(TIM2);
+    declare!(TIM3);
+    declare!(TIM6_DAC);
+    declare!(TIM7);
+    declare!(TIM21);
+    declare!(I2C3);
+    declare!(TIM22);
+    declare!(I2C1);
+    declare!(I2C2);
+    declare!(SPI1);
+    declare!(SPI2);
+    declare!(USART1);
+    declare!(USART2);
+    declare!(AES_RNG_LPUART1);
+    declare!(LCD);
+    declare!(USB);
+}
+
+pub use irqs::*;
diff --git a/embassy-stm32l0/src/lib.rs b/embassy-stm32l0/src/lib.rs
new file mode 100644
index 000000000..c4fa15c54
--- /dev/null
+++ b/embassy-stm32l0/src/lib.rs
@@ -0,0 +1,32 @@
+#![no_std]
+#![feature(generic_associated_types)]
+#![feature(asm)]
+#![feature(type_alias_impl_trait)]
+#![allow(incomplete_features)]
+
+#[cfg(not(any(
+    feature = "stm32l0x1",
+    feature = "stm32l0x2",
+    feature = "stm32l0x3",
+)))]
+compile_error!(
+    "No chip feature activated. You must activate exactly one of the following features: "
+);
+
+#[cfg(any(
+    all(feature = "stm32l0x1", feature = "stm32l0x2"),
+    all(feature = "stm32l0x1", feature = "stm32l0x3"),
+    all(feature = "stm32l0x2", feature = "stm32l0x3"),
+))]
+compile_error!(
+    "Multile chip features activated. You must activate exactly one of the following features: "
+);
+
+pub use stm32l0xx_hal as hal;
+pub use stm32l0xx_hal::pac;
+
+// This mod MUST go first, so that the others see its macros.
+pub(crate) mod fmt;
+
+pub mod exti;
+pub mod interrupt;