ipa: vimc: Send and retrieve FrameBuffers from IPA

Plumb through VIMC mojo interface to enable buffers passing.
VIMC does not have parameters or statistics buffers but we can
mimick the typical case of passing IPA buffers from pipeline
handler to IPA using mock buffers. The mock IPA buffers are
FrameBuffers which are dmabuf backed (in other words, mmap()able
through MappedFramebuffer inside the IPA).

This commits shows:
- Passing the parameter buffer from the pipeline handler to
  the IPA through functions defined in mojom interface.
- Passing request controls ControlList to the IPA.

Any tests using VIMC will now loop in the IPA paths. Any tests running
in isolated mode will help us to test IPA IPC code paths especially
around (de)serialization of data passing from pipeline handlers to the
IPA. Future IPA interface tests can simply extend the vimc mojom
interface to achieve/test a specific use case as required.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/libcamera/ipa/vimc.mojom

@@ -29,8 +29,17 @@ interface IPAVimcInterface {
 
 	mapBuffers(array<libcamera.IPABuffer> buffers);
 	unmapBuffers(array<uint32> ids);
+
+	/*
+	 * The vimc driver doesn't use parameters buffers. To maximize coverage
+	 * of unit tests that rely on the VIMC pipeline handler, we still define
+	 * interface functions that mimick how other pipeline handlers typically
+	 * handle parameters at runtime.
+	 */
+	[async] fillParams(uint32 frame, uint32 bufferId);
+	[async] processControls(uint32 frame, libcamera.ControlList controls);
 };
 
 interface IPAVimcEventInterface {
-	dummyEvent(uint32 val);
+	paramsFilled(uint32 bufferId);
 };

src/ipa/vimc/vimc.cpp

@@ -43,6 +43,9 @@ public:
 	void mapBuffers(const std::vector<IPABuffer> &buffers) override;
 	void unmapBuffers(const std::vector<unsigned int> &ids) override;
 
+	void fillParams(uint32_t frame, uint32_t bufferId) override;
+	void processControls(uint32_t frame, const ControlList &controls) override;
+
 private:
 	void initTrace();
 	void trace(enum ipa::vimc::IPAOperationCode operation);
@@ -126,6 +129,22 @@ void IPAVimc::unmapBuffers(const std::vector<unsigned int> &ids)
 	}
 }
 
+void IPAVimc::fillParams([[maybe_unused]] uint32_t frame, uint32_t bufferId)
+{
+	auto it = buffers_.find(bufferId);
+	if (it == buffers_.end()) {
+		LOG(IPAVimc, Error) << "Could not find parameter buffer";
+		return;
+	}
+
+	paramsFilled.emit(bufferId);
+}
+
+void IPAVimc::processControls([[maybe_unused]] uint32_t frame,
+			      [[maybe_unused]] const ControlList &controls)
+{
+}
+
 void IPAVimc::initTrace()
 {
 	struct stat fifoStat;

src/libcamera/pipeline/vimc/vimc.cpp

@@ -52,6 +52,7 @@ public:
 	int init();
 	int allocateMockIPABuffers();
 	void bufferReady(FrameBuffer *buffer);
+	void paramsFilled(unsigned int id);
 
 	MediaDevice *media_;
 	std::unique_ptr<CameraSensor> sensor_;
@@ -431,6 +432,8 @@ int PipelineHandlerVimc::queueRequestDevice(Camera *camera, Request *request)
 	if (ret < 0)
 		return ret;
 
+	data->ipa_->processControls(request->sequence(), request->controls());
+
 	return 0;
 }
 
@@ -464,6 +467,8 @@ bool PipelineHandlerVimc::match(DeviceEnumerator *enumerator)
 		return false;
 	}
 
+	data->ipa_->paramsFilled.connect(data.get(), &VimcCameraData::paramsFilled);
+
 	std::string conf = data->ipa_->configurationFile("vimc.conf");
 	data->ipa_->init(IPASettings{ conf, data->sensor_->model() });
 
@@ -568,6 +573,8 @@ void VimcCameraData::bufferReady(FrameBuffer *buffer)
 
 	pipe_->completeBuffer(request, buffer);
 	pipe_->completeRequest(request);
+
+	ipa_->fillParams(request->sequence(), mockIPABufs_[0]->cookie());
 }
 
 int VimcCameraData::allocateMockIPABuffers()
@@ -585,6 +592,10 @@ int VimcCameraData::allocateMockIPABuffers()
 	return video_->exportBuffers(kBufCount, &mockIPABufs_);
 }
 
+void VimcCameraData::paramsFilled([[maybe_unused]] unsigned int id)
+{
+}
+
 REGISTER_PIPELINE_HANDLER(PipelineHandlerVimc)
 
 } /* namespace libcamera */