zephyr: test: add test case for user-space ll scheduling

Add a test case to run tasks with low-latency (LL) scheduler in
user-space. The test does not yet use any audio pipeline functionality,
but uses similar interfaces towards the SOF scheduler interface.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

zephyr/test/CMakeLists.txt

@@ -19,3 +19,7 @@ endif()
 if (CONFIG_SOF_BOOT_TEST_STANDALONE AND CONFIG_USERSPACE)
   zephyr_library_sources(userspace/test_mailbox.c)
 endif()
+
+if (CONFIG_SOF_BOOT_TEST_STANDALONE AND CONFIG_SOF_USERSPACE_LL)
+  zephyr_library_sources(userspace/test_ll_task.c)
+endif()

zephyr/test/userspace/README.md

@@ -12,12 +12,18 @@ Available tests:
    - Test Zephyr DAI interface, together with SOF DMA
      wrapper from a user thread. Mimics the call flows done in
      sof/src/audio/dai-zephyr.c. Use cavstool.py as host runner.
+- test_ll_task.c
+   - Test Low-Latency (LL) scheduler in user-space mode. Creates
+     a user-space LL scheduler, and uses it to create and run tasks.
+   - Tests functionality used by SOF audio pipeline framework to
+     create tasks for audio pipeline logic.
 - test_mailbox.c
    - Test use of sof/mailbox.h interface from a Zephyr user thread.
 
 Building for Intel Panther Lake:
 ./scripts/xtensa-build-zephyr.py --cmake-args=-DCONFIG_SOF_BOOT_TEST_STANDALONE=y \
         --cmake-args=-DCONFIG_SOF_USERSPACE_INTERFACE_DMA=y \
+        --cmake-args=-DCONFIG_SOF_USERSPACE_LL=y \
         -o app/overlays/ptl/userspace_overlay.conf -o app/winconsole_overlay.conf ptl
 
 Running test:

zephyr/test/userspace/test_ll_task.c

@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Copyright(c) 2026 Intel Corporation.
+ */
+
+/*
+ * Test case for creation of low-latency threads in user-space.
+ */
+
+#include <sof/boot_test.h>
+#include <sof/lib/mailbox.h>
+#include <sof/lib/uuid.h>
+#include <sof/schedule/schedule.h>
+#include <sof/schedule/ll_schedule.h>
+#include <sof/schedule/ll_schedule_domain.h>
+#include <rtos/task.h>
+#include <rtos/userspace_helper.h>
+#include <ipc4/fw_reg.h>
+
+#include <zephyr/kernel.h>
+#include <zephyr/ztest.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/app_memory/app_memdomain.h>
+
+#include <stddef.h> /* offsetof() */
+
+LOG_MODULE_DECLARE(sof_boot_test, LOG_LEVEL_DBG);
+
+/* f11818eb-e92e-4082-82a3-dc54c604ebf3 */
+SOF_DEFINE_UUID("test_task", test_task_uuid, 0xf11818eb, 0xe92e, 0x4082,
+		0x82,  0xa3, 0xdc, 0x54, 0xc6, 0x04, 0xeb, 0xf3);
+
+K_APPMEM_PARTITION_DEFINE(userspace_ll_part);
+
+/* Global variable for test runs counter, accessible from user-space */
+K_APP_BMEM(userspace_ll_part) static int test_runs;
+
+static enum task_state task_callback(void *arg)
+{
+	LOG_INF("entry");
+
+	if (++test_runs > 3)
+		return SOF_TASK_STATE_COMPLETED;
+
+	return SOF_TASK_STATE_RESCHEDULE;
+}
+
+static void ll_task_test(void)
+{
+	struct task *task;
+	int priority = 0;
+	int core = 0;
+	int ret;
+
+	/* Initialize global test runs counter */
+	test_runs = 0;
+
+	task = zephyr_ll_task_alloc();
+	zassert_not_null(task, "task allocation failed");
+
+	/* allow user space to report status via 'test_runs' */
+	k_mem_domain_add_partition(zephyr_ll_mem_domain(), &userspace_ll_part);
+
+	/* work in progress, see pipeline-schedule.c */
+	ret = schedule_task_init_ll(task, SOF_UUID(test_task_uuid), SOF_SCHEDULE_LL_TIMER,
+				    priority, task_callback,
+				    (void *)&test_runs, core, 0);
+	zassert_equal(ret, 0);
+
+	LOG_INF("task init done");
+
+	/* Schedule the task to run immediately with 1ms period */
+	ret = schedule_task(task, 0, 1000);  /* 0 = start now, 1000us = 1ms period */
+	zassert_equal(ret, 0);
+
+	LOG_INF("task scheduled and running");
+
+	/* Let the task run for a bit */
+	k_sleep(K_MSEC(10));
+
+	/* Cancel the task to stop any scheduled execution */
+	ret = schedule_task_cancel(task);
+	zassert_equal(ret, 0);
+
+	/* Free task resources */
+	ret = schedule_task_free(task);
+	zassert_equal(ret, 0);
+
+	LOG_INF("test complete");
+}
+
+ZTEST(userspace_ll, ll_task_test)
+{
+	ll_task_test();
+}
+
+ZTEST_SUITE(userspace_ll, NULL, NULL, NULL, NULL, NULL);
+
+/**
+ * SOF main has booted up and IPC handling is stopped.
+ * Run test suites with ztest_run_all.
+ */
+static int run_tests(void)
+{
+	ztest_run_test_suite(userspace_ll, false, 1, 1, NULL);
+	return 0;
+}
+
+SYS_INIT(run_tests, APPLICATION, 99);