test: media_device: Add link handling test

Add a test unit that exercise link handling on the VIMC media graph.

Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

test/media_device/media_device_link_test.cpp

@@ -0,0 +1,246 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * media_device_link_test.cpp - Tests link handling on VIMC media device
+ */
+#include <iostream>
+#include <memory>
+
+#include "device_enumerator.h"
+#include "media_device.h"
+
+#include "test.h"
+
+using namespace libcamera;
+using namespace std;
+
+/*
+ * This link test requires a vimc device in order to exercise the
+ * MediaObject link handling API on a graph with a predetermined topology.
+ *
+ * vimc is a Media Controller kernel driver that creates virtual devices.
+ * From a userspace point of view they appear as normal media controller
+ * devices, but are not backed by any particular piece of hardware. They can
+ * thus be used for testing purpose without depending on a particular hardware
+ * platform.
+ *
+ * If no vimc device is found (most likely because the vimc driver is not
+ * loaded) the test is skipped.
+ */
+
+class MediaDeviceLinkTest : public Test
+{
+	int init()
+	{
+		enumerator = unique_ptr<DeviceEnumerator>(DeviceEnumerator::create());
+		if (!enumerator) {
+			cerr << "Failed to create device enumerator" << endl;
+			return TestFail;
+		}
+
+		if (enumerator->enumerate()) {
+			cerr << "Failed to enumerate media devices" << endl;
+			return TestFail;
+		}
+
+		DeviceMatch dm("vimc");
+		dev_ = enumerator->search(dm);
+		if (!dev_) {
+			cerr << "No VIMC media device found: skip test" << endl;
+			return TestSkip;
+		}
+
+		dev_->acquire();
+
+		if (dev_->open()) {
+			cerr << "Failed to open media device at "
+			     << dev_->devnode() << endl;
+			return TestFail;
+		}
+
+		return 0;
+	}
+
+	int run()
+	{
+		/*
+		 * First of all disable all links in the media graph to
+		 * ensure we start from a known state.
+		 */
+		if (dev_->disableLinks()) {
+			cerr << "Failed to disable all links in the media graph";
+			return TestFail;
+		}
+
+		/*
+		 * Test if link can be consistently retrieved through the
+		 * different methods the media device offers.
+		 */
+		string linkName("'Debayer A':[1] -> 'Scaler':[0]'");
+		MediaLink *link = dev_->link("Debayer A", 1, "Scaler", 0);
+		if (!link) {
+			cerr << "Unable to find link: " << linkName
+			     << " using lookup by name" << endl;
+			return TestFail;
+		}
+
+		MediaEntity *source = dev_->getEntityByName("Debayer A");
+		if (!source) {
+			cerr << "Unable to find entity: 'Debayer A'" << endl;
+			return TestFail;
+		}
+
+		MediaEntity *sink = dev_->getEntityByName("Scaler");
+		if (!sink) {
+			cerr << "Unable to find entity: 'Scaler'" << endl;
+			return TestFail;
+		}
+
+		MediaLink *link2 = dev_->link(source, 1, sink, 0);
+		if (!link2) {
+			cerr << "Unable to find link: " << linkName
+			     << " using lookup by entity" << endl;
+			return TestFail;
+		}
+
+		if (link != link2) {
+			cerr << "Link lookup by name and by entity don't match"
+			     << endl;
+			return TestFail;
+		}
+
+		link2 = dev_->link(source->getPadByIndex(1),
+				   sink->getPadByIndex(0));
+		if (!link2) {
+			cerr << "Unable to find link: " << linkName
+			     << " using lookup by pad" << endl;
+			return TestFail;
+		}
+
+		if (link != link2) {
+			cerr << "Link lookup by name and by pad don't match"
+			     << endl;
+			return TestFail;
+		}
+
+		/* After reset the link shall not be enabled. */
+		if (link->flags() & MEDIA_LNK_FL_ENABLED) {
+			cerr << "Link " << linkName
+			     << " should not be enabled after a device reset"
+			     << endl;
+			return TestFail;
+		}
+
+		/* Enable the link and test if enabling was successful. */
+		if (link->setEnabled(true)) {
+			cerr << "Failed to enable link: " << linkName
+			     << endl;
+			return TestFail;
+		}
+
+		if (!(link->flags() & MEDIA_LNK_FL_ENABLED)) {
+			cerr << "Link " << linkName
+			     << " was enabled but it is reported as disabled"
+			     << endl;
+			return TestFail;
+		}
+
+		/* Disable the link and test if disabling was successful. */
+		if (link->setEnabled(false)) {
+			cerr << "Failed to disable link: " << linkName
+			     << endl;
+			return TestFail;
+		}
+
+		if (link->flags() & MEDIA_LNK_FL_ENABLED) {
+			cerr << "Link " << linkName
+			     << " was disabled but it is reported as enabled"
+			     << endl;
+			return TestFail;
+		}
+
+		/* Try to get a non existing link. */
+		linkName = "'Sensor A':[1] -> 'Scaler':[0]";
+		link = dev_->link("Sensor A", 1, "Scaler", 0);
+		if (link) {
+			cerr << "Link lookup for " << linkName
+			     << " succeeded but link does not exist"
+			     << endl;
+			return TestFail;
+		}
+
+		/* Now get an immutable link and try to disable it. */
+		linkName = "'Sensor A':[0] -> 'Raw Capture 0':[0]";
+		link = dev_->link("Sensor A", 0, "Raw Capture 0", 0);
+		if (!link) {
+			cerr << "Unable to find link: " << linkName
+			     << " using lookup by name" << endl;
+			return TestFail;
+		}
+
+		if (!(link->flags() & MEDIA_LNK_FL_IMMUTABLE)) {
+			cerr << "Link " << linkName
+			     << " should be 'IMMUTABLE'" << endl;
+			return TestFail;
+		}
+
+		/* Disabling an immutable link shall fail. */
+		if (!link->setEnabled(false)) {
+			cerr << "Disabling immutable link " << linkName
+			     << " succeeded but should have failed" << endl;
+			return TestFail;
+		}
+
+		/*
+		 * Enable an disabled link, and verify it is disabled again
+		 * after disabling all links in the media graph.
+		 */
+		linkName = "'Debayer B':[1] -> 'Scaler':[0]'";
+		link = dev_->link("Debayer B", 1, "Scaler", 0);
+		if (!link) {
+			cerr << "Unable to find link: " << linkName
+			     << " using lookup by name" << endl;
+			return TestFail;
+		}
+
+		if (link->setEnabled(true)) {
+			cerr << "Failed to enable link: " << linkName
+			     << endl;
+			return TestFail;
+		}
+
+		if (!(link->flags() & MEDIA_LNK_FL_ENABLED)) {
+			cerr << "Link " << linkName
+			     << " was enabled but it is reported as disabled"
+			     << endl;
+			return TestFail;
+		}
+
+		if (dev_->disableLinks()) {
+			cerr << "Failed to disable all links in the media graph";
+			return TestFail;
+		}
+
+		if (link->flags() & MEDIA_LNK_FL_ENABLED) {
+			cerr << "All links in the media graph have been disabled"
+			     << " but link " << linkName
+			     << " is still reported as enabled"  << endl;
+			return TestFail;
+		}
+
+		return 0;
+	}
+
+	void cleanup()
+	{
+		dev_->close();
+		dev_->release();
+	}
+
+private:
+	unique_ptr<DeviceEnumerator> enumerator;
+	MediaDevice *dev_;
+};
+
+TEST_REGISTER(MediaDeviceLinkTest);

test/media_device/meson.build

@@ -1,5 +1,6 @@
 media_device_tests = [
     ['media_device_print_test',         'media_device_print_test.cpp'],
+    ['media_device_link_test',          'media_device_link_test.cpp'],
 ]
 
 foreach t : media_device_tests