Re: [PATCH v4] coresight: Add a KUnit test for coresight_find_default_sink()
From: James Clark
Date: Mon Mar 17 2025 - 07:03:38 EST
On 14/03/2025 12:35 pm, Anshuman Khandual wrote:
On 3/12/25 16:01, James Clark wrote:
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.
The test overall looks good but there are some comments below.
Reviewed-by: Leo Yan <leo.yan@xxxxxxx>
Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
---
Changes in v4:
- Rename etm to src now that it's not CORESIGHT_DEV_SUBTYPE_SOURCE_PROC
- Remove the now empty src_ops too
- Fix a rebase mistake in the Makefile that removed CTCU
- Link to v3: https://lore.kernel.org/r/20250312-james-cs-kunit-test-v3-1-dcfb69730161@xxxxxxxxxx
Changes in v3:
- Use CORESIGHT_DEV_SUBTYPE_SOURCE_BUS type instead of the default
(CORESIGHT_DEV_SUBTYPE_SOURCE_PROC) so that the test still works even
when TRBE sinks are registered. This also removes the need for the
fake CPU ID callback.
- Link to v2: https://lore.kernel.org/r/20250305-james-cs-kunit-test-v2-1-83ba682b976c@xxxxxxxxxx
Changes in v2:
- Let devm free everything rather than doing individual kfrees:
"Like with managed drivers, KUnit-managed fake devices are
automatically cleaned up when the test finishes, but can be manually
cleaned up early with kunit_device_unregister()."
- Link to v1: https://lore.kernel.org/r/20250225164639.522741-1-james.clark@xxxxxxxxxx
---
drivers/hwtracing/coresight/Kconfig | 9 +++
drivers/hwtracing/coresight/Makefile | 1 +
drivers/hwtracing/coresight/coresight-core.c | 1 +
.../hwtracing/coresight/coresight-kunit-tests.c | 74 ++++++++++++++++++++++
4 files changed, 85 insertions(+)
diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index ecd7086a5b83..f064e3d172b3 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -259,4 +259,13 @@ 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.
The description sounds adequate given that more unit tests might be added later.
+
endif
diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
index 8e62c3150aeb..4e6ea5b05b01 100644
--- a/drivers/hwtracing/coresight/Makefile
+++ b/drivers/hwtracing/coresight/Makefile
@@ -53,3 +53,4 @@ obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o
obj-$(CONFIG_CORESIGHT_DUMMY) += coresight-dummy.o
obj-$(CONFIG_CORESIGHT_CTCU) += coresight-ctcu.o
coresight-ctcu-y := coresight-ctcu-core.o
+obj-$(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 fb43ef6a3b1f..47af75ba7a00 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -959,6 +959,7 @@ coresight_find_default_sink(struct coresight_device *csdev)
}
return csdev->def_sink;
}
+EXPORT_SYMBOL_GPL(coresight_find_default_sink);
This symbol needs exporting given that the kunit test here can also be built
as a module.
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..c8f361767c45
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-kunit-tests.c
@@ -0,0 +1,74 @@
+// 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);
Guess both these memory allocations gets freed up here automatically
via kunit_device's device framework when the test suit exits ?
Yes, see the change log in the cover letter.
+ return csdev;
+}
+
+static void test_default_sink(struct kunit *test)
+{
+ /*
+ * Source -> ETF -> ETR -> CATU
+ * ^
+ * | default
+ */
Should some more random path combinations involving ETR and ETF along with
other coresight devices also be tested where ETR gets selected as default ?
Probably, but I only added what was required to test Steve's original
bug report. We can add more tests for coresight_find_default_sink() if
when it gets changed or refactored in the future. At the moment without
any changes in sight there wouldn't be any benefit.
+ struct device *dev = kunit_device_register(test, "coresight_kunit");
+ struct coresight_device *src = coresight_test_device(dev),
+ *etf = coresight_test_device(dev),
+ *etr = coresight_test_device(dev),
+ *catu = coresight_test_device(dev);
+ struct coresight_connection conn = {};
+
+ src->type = CORESIGHT_DEV_TYPE_SOURCE;
+ /*
+ * Don't use CORESIGHT_DEV_SUBTYPE_SOURCE_PROC, that would always return
+ * a TRBE sink if one is registered.
Probably this should be tested as well i.e when TRBE sink is also available
and it gets picked up as a default.
This is quite simple logic so it's probably even less of a valuable
test. I only added a test for the other sinks because the recursive
search for them is not easy code to follow by eye.