Embassy for MSPM0

This adds an embassy hal for the Texas Instruments MSPM0 microcontroller series.

So far the GPIO and time drivers have been implemented. I have tested these drivers on the following parts:
- C1104
- L1306
- L2228
- G3507
- G3519

The PAC is generated at https://github.com/mspm0-rs

examples/mspm0c1104/.cargo/config.toml

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+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+# replace MSPM0C1104 with your chip as listed in `probe-rs chip list`
+runner = "probe-rs run --chip MSPM0C1104 --protocol=swd"
+
+[build]
+target = "thumbv6m-none-eabi"
+
+[env]
+DEFMT_LOG = "debug"
+# defmt's buffer needs to be shrunk since the MSPM0C1104 only has 1KB of ram.
+DEFMT_RTT_BUFFER_SIZE = "72"

examples/mspm0c1104/Cargo.toml

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+[package]
+edition = "2021"
+name = "embassy-mspm0-c1104-examples"
+version = "0.1.0"
+license = "MIT OR Apache-2.0"
+
+[dependencies]
+embassy-mspm0 = { version = "0.1.0", path = "../../embassy-mspm0", features = ["mspm0c110x", "rt", "time-driver-any"] }
+embassy-executor = { version = "0.7.0", path = "../../embassy-executor", features = ["task-arena-size-128", "arch-cortex-m", "executor-thread", "executor-interrupt"] }
+embassy-sync = { version = "0.6.2", path = "../../embassy-sync", features = ["defmt"] }
+embassy-time = { version = "0.4.0", path = "../../embassy-time", features = ["defmt"] }
+panic-halt = "0.2.0"
+cortex-m = { version = "0.7.6", features = ["inline-asm", "critical-section-single-core"] }
+cortex-m-rt = { version = "0.7.0"}
+defmt = "0.3"
+defmt-rtt = "0.4"
+panic-probe = { version = "0.3.2", features = ["print-defmt"] }
+panic-semihosting = "0.6.0"
+
+# The chip only has 1KB of ram, so we must optimize binaries regardless
+[profile.dev]
+debug = 2
+opt-level = "z"
+lto = true
+codegen-units = 1
+# strip = true
+
+[profile.release]
+debug = 2
+opt-level = "z"
+lto = true
+codegen-units = 1

examples/mspm0c1104/README.md

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+# Examples for MSPM0C110x family
+
+Run individual examples with
+```
+cargo run --bin <module-name>
+```
+for example
+```
+cargo run --bin blinky
+```
+
+## Checklist before running examples
+A large number of the examples are written for the [LP-MSPM0C1104](https://www.ti.com/tool/LP-MSPM0C1104) board.
+
+You might need to adjust `.cargo/config.toml`, `Cargo.toml` and possibly update pin numbers or peripherals to match the specific MCU or board you are using.
+
+* [ ] Update .cargo/config.toml with the correct probe-rs command to use your specific MCU. For example for C1104 it should be `probe-rs run --chip MSPM0C1104`. (use `probe-rs chip list` to find your chip)
+* [ ] Update Cargo.toml to have the correct `embassy-mspm0` feature. For example for C1104 it should be `mspm0c1104`. Look in the `Cargo.toml` file of the `embassy-mspm0` project to find the correct feature flag for your chip.
+* [ ] If your board has a special clock or power configuration, make sure that it is set up appropriately.
+* [ ] If your board has different pin mapping, update any pin numbers or peripherals in the given example code to match your schematic
+
+If you are unsure, please drop by the Embassy Matrix chat for support, and let us know:
+
+* Which example you are trying to run
+* Which chip and board you are using
+
+Embassy Chat: https://matrix.to/#/#embassy-rs:matrix.org

examples/mspm0c1104/build.rs

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+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    File::create(out.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out.display());
+
+    // By default, Cargo will re-run a build script whenever
+    // any file in the project changes. By specifying `memory.x`
+    // here, we ensure the build script is only re-run when
+    // `memory.x` is changed.
+    println!("cargo:rerun-if-changed=memory.x");
+
+    println!("cargo:rustc-link-arg-bins=--nmagic");
+    println!("cargo:rustc-link-arg-bins=-Tlink.x");
+    println!("cargo:rustc-link-arg-bins=-Tdefmt.x");
+}

examples/mspm0c1104/memory.x

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+MEMORY
+{
+  FLASH : ORIGIN = 0x00000000, LENGTH = 16K
+  RAM   : ORIGIN = 0x20000000, LENGTH = 1K
+}

examples/mspm0c1104/src/bin/blinky.rs

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+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_mspm0::{
+    gpio::{Level, Output},
+    Config,
+};
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_halt as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    info!("Hello world!");
+    let p = embassy_mspm0::init(Config::default());
+
+    let mut led1 = Output::new(p.PA22, Level::Low);
+    led1.set_inversion(true);
+
+    loop {
+        Timer::after_millis(400).await;
+
+        info!("Toggle");
+        led1.toggle();
+    }
+}

examples/mspm0c1104/src/bin/button.rs

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+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_mspm0::{
+    gpio::{Input, Level, Output, Pull},
+    Config,
+};
+use {defmt_rtt as _, panic_halt as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    info!("Hello world!");
+
+    let p = embassy_mspm0::init(Config::default());
+
+    let led1 = p.PA22;
+    let s2 = p.PA16;
+
+    let mut led1 = Output::new(led1, Level::Low);
+
+    let mut s2 = Input::new(s2, Pull::Up);
+
+    // led1 is active low
+    led1.set_high();
+
+    loop {
+        s2.wait_for_falling_edge().await;
+
+        info!("Switch 2 was pressed");
+
+        led1.toggle();
+    }
+}