@@ -3,5 +3,17 @@
Uthread API
===========
+.. kernel-doc:: include/uthread.h
+ :doc: Overview
+
.. kernel-doc:: include/uthread.h
:internal:
+
+Example
+-------
+
+Here is an example of how to use this API:
+
+.. literalinclude:: ../../test/lib/uthread.c
+ :language: c
+ :linenos:
@@ -31,6 +31,7 @@ obj-$(CONFIG_CRC8) += test_crc8.o
obj-$(CONFIG_UT_LIB_CRYPT) += test_crypt.o
obj-$(CONFIG_UT_TIME) += time.o
obj-$(CONFIG_$(XPL_)UT_UNICODE) += unicode.o
+obj-$(CONFIG_UTHREAD) += uthread.o
obj-$(CONFIG_LIB_UUID) += uuid.o
else
obj-$(CONFIG_SANDBOX) += kconfig_spl.o
new file mode 100644
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2025 Linaro Limited
+ *
+ * Unit test for uthread
+ */
+
+#include <stdbool.h>
+#include <test/lib.h>
+#include <test/ut.h>
+#include <uthread.h>
+
+static int count;
+
+/* A thread entry point */
+static void worker(void *arg)
+{
+ int loops = (int)(unsigned long)arg;
+ int i;
+
+ for (i = 0; i < loops; i++) {
+ count++;
+ uthread_schedule();
+ }
+}
+
+/*
+ * lib_uthread() - testing the uthread API
+ *
+ * This function creates two threads with the same entry point. The first one
+ * receives 5 as an argument, the second one receives 10. The number indicates
+ * the number of time the worker thread should loop on uthread_schedule()
+ * before returning. The workers increment a global counter each time they loop.
+ * As a result the main thread knows how many times it should call
+ * uthread_schedule() to let the two threads proceed, and it also knows which
+ * value the counter should have at any moment.
+ */
+static int lib_uthread(struct unit_test_state *uts)
+{
+ int i;
+ int id1, id2;
+
+ count = 0;
+ id1 = uthread_grp_new_id();
+ ut_assert(id1 != 0);
+ id2 = uthread_grp_new_id();
+ ut_assert(id2 != 0);
+ ut_assert(id1 != id2);
+ ut_assertok(uthread_create(NULL, worker, (void *)5, 0, id1));
+ ut_assertok(uthread_create(NULL ,worker, (void *)10, 0, 0));
+ /*
+ * The first call is expected to schedule the first worker, which will
+ * schedule the second one, which will schedule back to the main thread
+ * (here). Therefore count should be 2.
+ */
+ ut_assert(uthread_schedule());
+ ut_asserteq(2, count);
+ ut_assert(!uthread_grp_done(id1));
+ /* Four more calls should bring the count to 10 */
+ for (i = 0; i < 4; i++) {
+ ut_assert(!uthread_grp_done(id1));
+ ut_assert(uthread_schedule());
+ }
+ ut_asserteq(10, count);
+ /* This one allows the first worker to exit */
+ ut_assert(uthread_schedule());
+ /* At this point there should be no runnable thread in group 'id1' */
+ ut_assert(uthread_grp_done(id1));
+ /* Five more calls for the second worker to finish incrementing */
+ for (i = 0; i < 5; i++)
+ ut_assert(uthread_schedule());
+ ut_asserteq(15, count);
+ /* Plus one call to let the second worker return from its entry point */
+ ut_assert(uthread_schedule());
+ /* Now both tasks should be done, schedule should return false */
+ ut_assert(!uthread_schedule());
+
+ return 0;
+}
+LIB_TEST(lib_uthread, 0);