tests: timer: Create timer test

Create a test to exercise the zephyr::timer timers.  This uses both
SimpleTimer and CallbackTimer intensely for 5 seconds and prints out the
results.

Signed-off-by: David Brown <[email protected]>

tests/timer/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(timer_rust)
+
+rust_cargo_application()

tests/timer/Cargo.toml

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+# Copyright (c) 2024 Linaro LTD
+# SPDX-License-Identifier: Apache-2.0
+
+[package]
+# This must be rustapp for now.
+name = "rustapp"
+version = "3.7.0"
+edition = "2021"
+description = "Tests of timeers"
+license = "Apache-2.0 or MIT"
+
+[lib]
+crate-type = ["staticlib"]
+
+[dependencies]
+rand = { version = "0.8", default-features = false }
+rand_pcg = { version = "0.3.1", default-features = false }
+zephyr = "3.7.0"

tests/timer/prj.conf

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+# Copyright (c) 2024 Linaro LTD
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_RUST=y
+CONFIG_MAIN_STACK_SIZE=2048
+
+# Timers need alloc
+CONFIG_RUST_ALLOC=y

tests/timer/src/lib.rs

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+// Copyright (c) 2024 Linaro LTD
+// SPDX-License-Identifier: Apache-2.0
+
+#![no_std]
+
+extern crate alloc;
+
+use core::{pin::Pin, sync::atomic::Ordering};
+
+use alloc::{boxed::Box, vec::Vec};
+use rand::Rng;
+use rand_pcg::Pcg32;
+use zephyr::{
+    printkln, sync::{atomic::AtomicUsize, Arc}, time::{Duration, NoWait, Tick}, timer::{Callback, CallbackTimer, SimpleTimer, StoppedTimer}
+};
+
+// Test the timers interface.  There are a couple of things this tries to test:
+// 1. Do timers dynamically allocated and dropped work.
+// 2. Can simple timers count properly.
+// 3. Can we wait on a Simple timer.
+// 4. Do callbacks work with messages and semaphores.
+
+#[no_mangle]
+extern "C" fn rust_main() {
+    printkln!("Tick frequency: {}", zephyr::time::SYS_FREQUENCY);
+    timer_test();
+    printkln!("All tests passed");
+}
+
+fn timer_test() {
+    let mut rng = Pcg32::new(1, 1);
+
+    // Track a global "stop" time when the entire test should be shut down.
+    // let mut total_test = StoppedTimer::new().start_simple(Duration::secs_at_least(5), NoWait);
+    let mut total_test = StoppedTimer::new().start_simple(Duration::secs_at_least(5), NoWait);
+
+    // This simple timer lets us pause periodically to allow other timers to build up.
+    let mut period = StoppedTimer::new().start_simple(
+        Duration::millis_at_least(100),
+        Duration::millis_at_least(100),
+    );
+
+    let mut simples: Vec<_> = (0..10).map(|_| TestSimple::new(&mut rng)).collect();
+    let atomics: Vec<_> = (0..10).map(|_| TestAtomic::new(&mut rng)).collect();
+
+    let mut count = 0;
+    loop {
+        // Wait for the period timer.
+        let num = period.read_count_wait();
+
+        if num > 1 {
+            // Getting this is actually a good indicator that we've overwhelmed ourselves with
+            // timers, and are stress testing things.
+            printkln!("Note: Missed period ticks");
+        }
+
+        count += 1;
+
+        if count % 10 == 0 {
+            printkln!("Ticks {}", count);
+        }
+
+        if total_test.read_count() > 0 {
+            break;
+        }
+
+        simples.iter_mut().for_each(|m| m.update());
+    }
+
+    // Collect all of the times they fired.
+    let simple_count: usize = simples.iter().map(|s| s.count).sum();
+    printkln!("Simple fired {} times", simple_count);
+    let atomic_count: usize = atomics.iter().map(|s| s.count()).sum();
+    printkln!("Atomics fired {} times", atomic_count);
+
+    printkln!("Period ticks: {}", count);
+
+    // Now that everything is done and cleaned up, allow a little time to pass to make sure there
+    // are no stray timers.  We can re-use the total test timer.
+    let mut total_test = total_test.stop().start_simple(Duration::millis_at_least(1), NoWait);
+    total_test.read_count_wait();
+}
+
+/// Test a SimpleTimer.
+///
+/// This allocates a simple timer, and starts it with a small somewhat random period.  It will track
+/// the total number of times that it fires when checked.
+struct TestSimple {
+    timer: SimpleTimer,
+    _delay: Tick,
+    count: usize,
+}
+
+impl TestSimple {
+    fn new(rng: &mut impl Rng) -> TestSimple {
+        let delay = rng.gen_range(2..16);
+        TestSimple {
+            timer: StoppedTimer::new()
+                .start_simple(Duration::from_ticks(delay), Duration::from_ticks(delay)),
+            _delay: delay,
+            count: 0,
+        }
+    }
+
+    /// Update from the total count from the timer itself.
+    fn update(&mut self) {
+        self.count += self.timer.read_count() as usize;
+    }
+}
+
+/// Test a callback using an atomic counter.
+///
+/// This allocates a Callback timer, and uses the callback to increment an atomic value.
+struct TestAtomic {
+    _timer: Pin<Box<CallbackTimer<Arc<AtomicUsize>>>>,
+    counter: Arc<AtomicUsize>,
+}
+
+impl TestAtomic {
+    fn new(rng: &mut impl Rng) -> TestAtomic {
+        let delay = rng.gen_range(2..16);
+        let counter = Arc::new(AtomicUsize::new(0));
+        TestAtomic {
+            _timer: StoppedTimer::new().start_callback(
+                Callback {
+                    call: Self::expiry,
+                    data: counter.clone(),
+                },
+                Duration::from_ticks(delay),
+                Duration::from_ticks(delay),
+            ),
+            counter: counter.clone(),
+        }
+    }
+
+    // Read the atomic count.
+    fn count(&self) -> usize {
+        self.counter.load(Ordering::Acquire)
+    }
+
+    /// Expire the function
+    fn expiry(data: &Arc<AtomicUsize>) {
+        data.fetch_add(1, Ordering::Relaxed);
+    }
+}

tests/timer/testcase.yaml

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+common:
+  filter: CONFIG_RUST_SUPPORTED
+  platform_allow:
+    - qemu_cortex_m0
+    - qemu_cortex_m3
+    - qemu_riscv32
+    - qemu_riscv32/qemu_virt_riscv32/smp
+    - qemu_riscv64
+    - qemu_riscv64/qemu_virt_riscv64/smp
+    - nrf52840dk/nrf52840
+tests:
+  test.rust.timer:
+    harness: console
+    harness_config:
+      type: one_line
+      regex:
+        - "All tests passed"