ESP32-C6 LP CORE delay and basic gpio (#715)

* ESP32-C6 LP CORE delay and basic gpio

* CHANGELOG.md, build LP examples in release mode

.github/workflows/ci.yml

@@ -244,7 +244,7 @@ jobs:
       # Perform a full build initially to verify that the examples not only
       # build, but also link successfully.
       - name: build esp32c6-lp-hal (no features)
-        run: cd esp32c6-lp-hal/ && cargo +nightly build --examples
+        run: cd esp32c6-lp-hal/ && cargo +nightly build --release --examples
       # Ensure documentation can be built
       - name: rustdoc
         run: cd esp32c6-lp-hal/ && cargo doc

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Add the `esp32c6-lp-hal` package (#714)
+- Add GPIO (output) and delay functionality to `esp32c6-lp-hal` (#715)
 
 ### Changed
 

esp32c6-lp-hal/.cargo/config.toml

@@ -1,7 +1,7 @@
 [target.riscv32imac-unknown-none-elf]
 runner = "espflash flash --monitor"
 rustflags = [
-  "-C", "link-arg=-Tlinkall.x",
+  "-C", "link-arg=-Tlink.x",
 ]
 
 [build]

esp32c6-lp-hal/Cargo.toml

@@ -25,6 +25,11 @@ critical-section = { version = "1.1.2", features = ["restore-state-u8"] }
 embedded-hal     = { version = "0.2.7", features = ["unproven"] }
 esp32c6-lp       = { git = "https://github.com/esp-rs/esp-pacs", rev = "a9cad5e", features = ["critical-section"] }
 riscv            = "0.10.1"
+riscv-rt-macros  = "0.2.0"
+paste            = "1.0.14"
+
+[dev-dependencies]
+panic-halt       = "0.2.0"
 
 [features]
 default = []

esp32c6-lp-hal/examples/blinky.rs

@@ -0,0 +1,34 @@
+//! Counts a 32 bit value at 0x5000_2000 and blinks GPIO 1.
+//! Make sure the LP RAM is cleared before loading the code.
+
+#![no_std]
+#![no_main]
+
+use esp32c6_lp_hal::{gpio::Io, prelude::*};
+use panic_halt as _;
+
+#[entry]
+fn main() -> ! {
+    let mut i: u32 = 0;
+
+    let peripherals = esp32c6_lp::Peripherals::take().unwrap();
+
+    let io = Io::new(peripherals.LP_IO);
+    let mut gpio1 = io.gpio1.into_output();
+
+    let ptr = 0x5000_2000 as *mut u32;
+    let mut delay = delay::Delay::new();
+
+    loop {
+        i = i.wrapping_add(1u32);
+        unsafe {
+            ptr.write_volatile(i);
+        }
+
+        gpio1.set_high().unwrap();
+        delay.delay_ms(500);
+
+        gpio1.set_low().unwrap();
+        delay.delay_ms(500);
+    }
+}

esp32c6-lp-hal/src/delay.rs

@@ -0,0 +1,41 @@
+//! Simple blocking delay functionality
+//!
+//! This uses the delay functionality provided by the `riscv` crate under the
+//! hood.
+
+use embedded_hal::blocking::delay::{DelayMs, DelayUs};
+
+use crate::CPU_CLOCK;
+
+pub struct Delay {
+    rv_delay: riscv::delay::McycleDelay,
+}
+
+impl Delay {
+    pub fn new() -> Self {
+        Self {
+            rv_delay: riscv::delay::McycleDelay::new(CPU_CLOCK),
+        }
+    }
+}
+
+impl DelayUs<u64> for Delay {
+    #[inline(always)]
+    fn delay_us(&mut self, us: u64) {
+        self.rv_delay.delay_us(us);
+    }
+}
+
+impl DelayUs<u32> for Delay {
+    #[inline(always)]
+    fn delay_us(&mut self, us: u32) {
+        self.rv_delay.delay_us(us);
+    }
+}
+
+impl DelayMs<u32> for Delay {
+    #[inline(always)]
+    fn delay_ms(&mut self, ms: u32) {
+        self.rv_delay.delay_ms(ms);
+    }
+}

esp32c6-lp-hal/src/gpio.rs

@@ -0,0 +1,80 @@
+//! LP-GPIO driver
+//!
+//! It's assumed that GPIOs are already configured correctly by the HP core.
+
+use core::{convert::Infallible, marker::PhantomData};
+
+use embedded_hal::digital::v2::OutputPin;
+
+pub struct Unknown {}
+
+pub struct Output;
+
+#[non_exhaustive]
+pub struct GpioPin<const PIN: u8, MODE> {
+    phantom: PhantomData<MODE>,
+}
+
+#[non_exhaustive]
+pub struct Io {
+    _peripheral: esp32c6_lp::LP_IO,
+
+    pub gpio0: GpioPin<0, Unknown>,
+    pub gpio1: GpioPin<1, Unknown>,
+    pub gpio2: GpioPin<2, Unknown>,
+    pub gpio3: GpioPin<3, Unknown>,
+    pub gpio4: GpioPin<4, Unknown>,
+    pub gpio5: GpioPin<5, Unknown>,
+    pub gpio6: GpioPin<6, Unknown>,
+    pub gpio7: GpioPin<7, Unknown>,
+}
+
+impl Io {
+    pub fn new(peripheral: esp32c6_lp::LP_IO) -> Self {
+        Self {
+            _peripheral: peripheral,
+            gpio0: GpioPin::new(),
+            gpio1: GpioPin::new(),
+            gpio2: GpioPin::new(),
+            gpio3: GpioPin::new(),
+            gpio4: GpioPin::new(),
+            gpio5: GpioPin::new(),
+            gpio6: GpioPin::new(),
+            gpio7: GpioPin::new(),
+        }
+    }
+}
+
+impl<const PIN: u8, MODE> GpioPin<PIN, MODE> {
+    fn new() -> Self {
+        GpioPin {
+            phantom: PhantomData::default(),
+        }
+    }
+
+    /// Assuming the GPIO is already configured by the HP core this makes the
+    /// GPIO into an output pin.
+    pub fn into_output(self) -> GpioPin<PIN, Output> {
+        GpioPin::new()
+    }
+}
+
+impl<const PIN: u8> OutputPin for GpioPin<PIN, Output> {
+    type Error = Infallible;
+
+    fn set_low(&mut self) -> Result<(), Self::Error> {
+        let lp_gpio = unsafe { &*esp32c6_lp::LP_IO::PTR };
+        lp_gpio
+            .out_w1tc
+            .write(|w| w.out_data_w1tc().variant(1 << PIN));
+        Ok(())
+    }
+
+    fn set_high(&mut self) -> Result<(), Self::Error> {
+        let lp_gpio = unsafe { &*esp32c6_lp::LP_IO::PTR };
+        lp_gpio
+            .out_w1ts
+            .write(|w| w.out_data_w1ts().variant(1 << PIN));
+        Ok(())
+    }
+}

esp32c6-lp-hal/src/lib.rs

@@ -2,6 +2,9 @@
 
 use core::arch::global_asm;
 
+pub mod delay;
+pub mod gpio;
+
 pub mod riscv {
     //! Low level access to RISC-V processors.
     //!
@@ -9,6 +12,9 @@ pub mod riscv {
 
     pub use riscv::*;
 }
+pub mod prelude;
+
+const CPU_CLOCK: u32 = 16_000_000;
 
 global_asm!(
     r#"

esp32c6-lp-hal/src/prelude.rs

@@ -0,0 +1,9 @@
+//! The prelude
+//!
+//! Re-exports all traits required for interacting with the various peripheral
+//! drivers implemented in this crate.
+
+pub use embedded_hal::{digital::v2::OutputPin, prelude::*};
+pub use riscv_rt_macros::entry;
+
+pub use crate::delay;