[PATCH] coresight: Add a KUnit test for coresight_find_default_sink()

[James Clark]

Add a test to confirm that default sink selection skips over an ETF
and returns an ETR even if it's further away.

This also makes it easier to add new unit tests in the future.

Signed-off-by: James Clark <james.clark at linaro.org>
---
 drivers/hwtracing/coresight/Kconfig           |  9 ++
 drivers/hwtracing/coresight/Makefile          |  1 +
 drivers/hwtracing/coresight/coresight-core.c  |  1 +
 .../coresight/coresight-kunit-tests.c         | 90 +++++++++++++++++++
 4 files changed, 101 insertions(+)
 create mode 100644 drivers/hwtracing/coresight/coresight-kunit-tests.c

diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index 06f0a7594169..056d04bc540a 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -247,4 +247,13 @@ config CORESIGHT_DUMMY
 
 	  To compile this driver as a module, choose M here: the module will be
 	  called coresight-dummy.
+
+config CORESIGHT_KUNIT_TESTS
+	  tristate "Enable Coresight unit tests"
+	  depends on KUNIT
+	  default KUNIT_ALL_TESTS
+	  help
+	    Enable Coresight unit tests. Only useful for development and not
+	    intended for production.
+
 endif
diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
index 4ba478211b31..c170a41b3056 100644
--- a/drivers/hwtracing/coresight/Makefile
+++ b/drivers/hwtracing/coresight/Makefile
@@ -51,3 +51,4 @@ coresight-cti-y := coresight-cti-core.o	coresight-cti-platform.o \
 		   coresight-cti-sysfs.o
 obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o
 obj-$(CONFIG_CORESIGHT_DUMMY) += coresight-dummy.o
+obj-$(CONFIG_CORESIGHT_KUNIT_TESTS) += coresight-kunit-tests.o
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index ea38ecf26fcb..ce63b68d5503 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -869,6 +869,7 @@ coresight_find_default_sink(struct coresight_device *csdev)
 	}
 	return csdev->def_sink;
 }
+EXPORT_SYMBOL_GPL(coresight_find_default_sink);
 
 static int coresight_remove_sink_ref(struct device *dev, void *data)
 {
diff --git a/drivers/hwtracing/coresight/coresight-kunit-tests.c b/drivers/hwtracing/coresight/coresight-kunit-tests.c
new file mode 100644
index 000000000000..d022bacc8357
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-kunit-tests.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <kunit/test.h>
+#include <kunit/device.h>
+#include <linux/coresight.h>
+
+#include "coresight-priv.h"
+
+static struct coresight_device *coresight_test_device(struct device *dev)
+{
+	struct coresight_device *csdev = devm_kcalloc(dev, 1,
+						     sizeof(struct coresight_device),
+						     GFP_KERNEL);
+	csdev->pdata = devm_kcalloc(dev, 1,
+				   sizeof(struct coresight_platform_data),
+				   GFP_KERNEL);
+	return csdev;
+}
+
+static void coresight_free_test_device(struct device *dev,
+				       struct coresight_device *csdev)
+{
+	devm_kfree(dev, csdev->pdata->out_conns);
+	devm_kfree(dev, csdev->pdata);
+	devm_kfree(dev, csdev);
+}
+
+static int coresight_test_cpuid(struct coresight_device *csdev)
+{
+	return 0;
+}
+
+static void test_default_sink(struct kunit *test)
+{
+	/*
+	 * ETM -> ETF -> ETR -> CATU
+	 *                ^
+	 *                | default
+	 */
+	struct device *dev = kunit_device_register(test, "coresight_kunit");
+	struct coresight_device *etm = coresight_test_device(dev),
+				*etf = coresight_test_device(dev),
+				*etr = coresight_test_device(dev),
+				*catu = coresight_test_device(dev);
+	struct coresight_connection conn = {};
+	struct coresight_ops_source src_ops = {.cpu_id = coresight_test_cpuid };
+	struct coresight_ops etm_cs_ops = { .source_ops	= &src_ops };
+
+	etm->type = CORESIGHT_DEV_TYPE_SOURCE;
+	etm->ops = &etm_cs_ops;
+	etf->type = CORESIGHT_DEV_TYPE_LINKSINK;
+	etf->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
+	etr->type = CORESIGHT_DEV_TYPE_SINK;
+	etr->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_SYSMEM;
+	catu->type = CORESIGHT_DEV_TYPE_HELPER;
+
+	conn.src_dev = etm;
+	conn.dest_dev = etf;
+	coresight_add_out_conn(dev, etm->pdata, &conn);
+
+	conn.src_dev = etf;
+	conn.dest_dev = etr;
+	coresight_add_out_conn(dev, etf->pdata, &conn);
+
+	conn.src_dev = etr;
+	conn.dest_dev = catu;
+	coresight_add_out_conn(dev, etr->pdata, &conn);
+
+	KUNIT_ASSERT_PTR_EQ(test, coresight_find_default_sink(etm), etr);
+
+	coresight_free_test_device(dev, etm);
+	coresight_free_test_device(dev, etf);
+	coresight_free_test_device(dev, etr);
+	coresight_free_test_device(dev, catu);
+}
+
+static struct kunit_case coresight_testcases[] = {
+	KUNIT_CASE(test_default_sink),
+	{}
+};
+
+static struct kunit_suite coresight_test_suite = {
+	.name = "coresight_test_suite",
+	.test_cases = coresight_testcases,
+};
+
+kunit_test_suites(&coresight_test_suite);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("James Clark <james.clark at linaro.org>");
+MODULE_DESCRIPTION("Arm CoreSight KUnit tests");
-- 
2.34.1