Add SYSTIMER based ESP32-C3 monotonic (#972)

* add esp32c3 monotonic

* fix tests

ci/expected/esp32c3/monotonic.run

@@ -0,0 +1,34 @@
+QEMU 8.2.0 monitor - type 'help' for more information
+(qemu) q
+ESP-ROM:esp32c3-api1-20210207
+Build:Feb  7 2021
+rst:0x1 (POWERON),boot:0x8 (SPI_FAST_FLASH_BOOT)
+SPIWP:0xee
+mode:DIO, clock div:2
+load:0x3fcd5820,len:0x1714
+load:0x403cc710,len:0x968
+load:0x403ce710,len:0x2f9c
+entry 0x403cc710
+I (0) boot: ESP-IDF v5.1.2-342-gbcf1645e44 2nd stage bootloader
+I (0) boot: compile time Dec 12 2023 10:50:58
+I (0) boot: chip revision: v0.3
+I (0) boot.esp32c3: SPI Speed      : 40MHz
+I (0) boot.esp32c3: SPI Mode       : SLOW READ
+I (0) boot.esp32c3: SPI Flash Size : 4MB
+I (0) boot: Enabling RNG early entropy source...
+I (1) boot: Partition Table:
+I (1) boot: ## Label            Usage          Type ST Offset   Length
+I (1) boot:  0 nvs              WiFi data        01 02 00009000 00006000
+I (1) boot:  1 phy_init         RF data          01 01 0000f000 00001000
+I (1) boot:  2 factory          factory app      00 00 00010000 003f0000
+I (1) boot: End of partition table
+I (1) esp_image: REDACTED
+I (3) esp_image: REDACTED
+I (3) esp_image: REDACTED
+I (8) esp_image: REDACTED
+I (11) boot: Loaded app from partition at offset 0x10000
+I (11) boot: Disabling RNG early entropy source...
+init
+hello from bar
+hello from baz
+hello from foo

examples/esp32c3/.cargo/config.toml

@@ -1,6 +1,6 @@
 [target.riscv32imc-unknown-none-elf]
 # Real hardware
-#runner = "espflash flash --monitor"
+# runner = "espflash flash --monitor"
 
 # QEMU emulator
 runner = "./runner.sh"
@@ -14,6 +14,3 @@ rustflags = [
 ]
 
 target = "riscv32imc-unknown-none-elf"
-
-[unstable]
-build-std = ["core"]

examples/esp32c3/Cargo.toml

@@ -8,6 +8,7 @@ license = "MIT OR Apache-2.0"
 
 [dependencies]
 rtic = {path = "../../rtic/"}
+rtic-monotonics = {path = "../../rtic-monotonics/"}
 esp-hal = { version = "0.16.1", features = ["esp32c3", "direct-vectoring", "interrupt-preemption"] }
 esp-backtrace = { version = "0.11.0", features = [
     "esp32c3",
@@ -21,4 +22,4 @@ esp-println = { version = "0.9.0", features = ["esp32c3", "uart"] }
 
 [features]
 test-critical-section = []
-riscv-esp32c3-backend = ["rtic/riscv-esp32c3-backend"]
+riscv-esp32c3-backend = ["rtic/riscv-esp32c3-backend", "rtic-monotonics/esp32c3-systimer"]

examples/esp32c3/README.md

@@ -15,12 +15,24 @@ This crate uses the most convenient option in ``cargo-espflash`` and ``espflash`
 
 ## Running the crate
 
+Uncomment the 
+
+```runner = "espflash flash --monitor"```
+
+line in ``.cargo/config.toml``
+
+and comment out (or remove) 
+
+```runner = "./runner.sh"```
+
+Now, running
+
 ```cargo run --example sw_and_hw --features=riscv-esp32c3-backend (--release)```
 
-should do the trick.
+in the root of this crate should do the trick.
 
 # Expected behavior
-The program
+The example ``sw_and_hw``
 - Prints ``init``
 - Enters a high prio task
 - During the execution of the high prio task, the button should be non-functional
@@ -31,3 +43,9 @@ The program
 - Exits the low prio task
 - Prints ``idle``
 
+The example ``monotonic``
+- Prints ``init``
+- Spawns the ``foo``, ``bar``, ``baz`` tasks (because of hardware interrupt latency dispatch, the order here may vary).
+- Each task prints ``hello from $TASK`` on entry
+- The tasks wait for 1, 2, 3 seconds respectively
+- Once the wait period is over, each task exits printing ``bye from $TASK`` (now in the proper order).

examples/esp32c3/examples/monotonic.rs

@@ -0,0 +1,51 @@
+#![no_main]
+#![no_std]
+use esp_backtrace as _;
+#[rtic::app(device = esp32c3, dispatchers = [])]
+mod app {
+    use rtic_monotonics::esp32c3::prelude::*;
+    esp32c3_systimer_monotonic!(Mono);
+    use esp_hal as _;
+    use esp_println::println;
+
+    #[shared]
+    struct Shared {}
+
+    #[local]
+    struct Local {}
+
+    #[init]
+    fn init(cx: init::Context) -> (Shared, Local) {
+        println!("init");
+        let timer = cx.device.SYSTIMER;
+
+        Mono::start(timer);
+
+        foo::spawn().unwrap();
+        bar::spawn().unwrap();
+        baz::spawn().unwrap();
+
+        (Shared {}, Local {})
+    }
+
+    #[task]
+    async fn foo(_cx: foo::Context) {
+        println!("hello from foo");
+        Mono::delay(2_u64.secs()).await;
+        println!("bye from foo");
+    }
+
+    #[task]
+    async fn bar(_cx: bar::Context) {
+        println!("hello from bar");
+        Mono::delay(3_u64.secs()).await;
+        println!("bye from bar");
+    }
+
+    #[task]
+    async fn baz(_cx: baz::Context) {
+        println!("hello from baz");
+        Mono::delay(4_u64.secs()).await;
+        println!("bye from baz");
+    }
+}

examples/esp32c3/examples/sw_and_hw.rs

@@ -1,6 +1,5 @@
 #![no_main]
 #![no_std]
-
 #[rtic::app(device = esp32c3, dispatchers=[FROM_CPU_INTR0, FROM_CPU_INTR1])]
 mod app {
     use esp_backtrace as _;

examples/esp32c3/rust-toolchain.toml

@@ -1,4 +1,4 @@
 [toolchain]
-channel = "nightly-2023-11-14"
+channel = "stable"
 components = ["rust-src"]
 targets = ["riscv32imc-unknown-none-elf"]

rtic-monotonics/CHANGELOG.md

@@ -13,6 +13,9 @@ For each category, *Added*, *Changed*, *Fixed* add new entries at the top!
 
 ## v2.0.2 - 2024-07-05
 
+### Added
+- `SYSTIMER` based monotonic for the ESP32-C3
+
 ### Fixed
 
 - Fix `stm32` monotonic for timer peripherals with only two clock compare modules

rtic-monotonics/Cargo.toml

@@ -31,6 +31,7 @@ features = [
     "stm32_tim4",
     "stm32_tim5",
     "stm32_tim15",
+    "esp32c3-systimer",
 ]
 rustdoc-flags = ["--cfg", "docsrs"]
 
@@ -65,6 +66,11 @@ stm32-metapac = { version = "15.0.0", optional = true }
 # i.MX RT
 imxrt-ral = { version = "0.5.3", optional = true }
 
+
+esp32c3 = {version = "0.22.0", optional = true }
+riscv = {version = "0.11.1", optional = true }
+
+
 [build-dependencies]
 proc-macro2 = { version = "1.0.36", optional = true }
 quote = { version = "1.0.15", optional = true }
@@ -104,6 +110,9 @@ imxrt = ["dep:cortex-m", "dep:imxrt-ral"]
 imxrt_gpt1 = ["imxrt"]
 imxrt_gpt2 = ["imxrt"]
 
+# ESP32-C3 Timer
+esp32c3-systimer = ["dep:esp32c3", "dep:riscv"]
+
 # STM32 timers
 # Use as `features = ["stm32g081kb", "stm32_tim15"]`
 stm32_tim2 = []