tests: kernel: Add support for stopping workqueues

This patch adds tests for stopping workqueues and reusing the resources of
a stopped workqueue.

Signed-off-by: Måns Ansgariusson <[email protected]>

tests/kernel/workq/work_queue/src/start_stop.c

@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2024 Måns Ansgariusson <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/ztest.h>
+
+#define NUM_TEST_ROUNDS 5
+#define NUM_TEST_ITEMS  10
+/* Each work item takes 100ms by default. */
+#define WORK_ITEM_WAIT  (CONFIG_TEST_WORK_ITEM_WAIT_MS)
+/* In fact, each work item could take up to this value */
+#define WORK_ITEM_WAIT_ALIGNED                                                                     \
+	k_ticks_to_ms_floor64(k_ms_to_ticks_ceil32(WORK_ITEM_WAIT) + _TICK_ALIGN)
+#define SUBMIT_WAIT (CONFIG_TEST_SUBMIT_WAIT_MS)
+#define STACK_SIZE  (1024 + CONFIG_TEST_EXTRA_STACK_SIZE)
+#define CHECK_WAIT  ((NUM_TEST_ITEMS + 1) * WORK_ITEM_WAIT_ALIGNED)
+
+static struct k_work_q work_q;
+static K_THREAD_STACK_DEFINE(work_q_stack, STACK_SIZE);
+
+struct k_work works[NUM_TEST_ITEMS];
+
+static atomic_t num_work_executed;
+static void work_handler(struct k_work *work)
+{
+	ARG_UNUSED(work);
+
+	atomic_inc(&num_work_executed);
+}
+
+static struct k_work_queue_config cfg = {
+	.name = "test_work_q",
+	.no_yield = true,
+};
+
+static void workq_setup(void)
+{
+	zassert_equal(k_work_queue_stop(&work_q), -ENODEV,
+		      "Succeeded to stop work queue on non-initialized work queue");
+	k_work_queue_start(&work_q, work_q_stack, K_THREAD_STACK_SIZEOF(work_q_stack),
+			   K_PRIO_PREEMPT(4), &cfg);
+}
+
+static void workq_teardown(void)
+{
+	struct k_work work;
+
+	zassert_equal(k_work_queue_stop(&work_q), -EBUSY,
+		      "Succeeded to stop work queue while it is running & not plugged");
+	zassert_true(k_work_queue_drain(&work_q, true) >= 0, "Failed to drain & plug work queue");
+	zassert_ok(k_work_queue_stop(&work_q), "Failed to stop work queue");
+
+	k_work_init(&work, work_handler);
+	zassert_equal(k_work_submit_to_queue(&work_q, &work), -ENODEV,
+		      "Succeeded to submit work item to non-initialized work queue");
+}
+
+ZTEST(workqueue_reuse, test_submit_to_queue)
+{
+	size_t i, j;
+
+	for (i = 0; i < NUM_TEST_ROUNDS; i++) {
+		workq_setup();
+		for (j = 0; j < NUM_TEST_ITEMS; j++) {
+			k_work_init(&works[j], work_handler);
+			zassert_equal(k_work_submit_to_queue(&work_q, &works[j]), 1,
+				      "Failed to submit work item");
+		}
+		/* Wait for the work item to complete */
+		k_sleep(K_MSEC(CHECK_WAIT));
+
+		/* Check that the work item was executed */
+		zassert_equal(atomic_get(&num_work_executed), i * j + j,
+			      "all work items were not executed within the expected time");
+		workq_teardown();
+	}
+}
+
+ZTEST_SUITE(workqueue_reuse, NULL, NULL, NULL, NULL, NULL);