libcamera: raspberrypi: Set camera flips correctly from user transform

The Raspberry Pi pipeline handler allows all transforms except those
involving a transpose. The user transform is combined with any
inherent rotation of the camera, and the camera's H and V flip bits
are set accordingly.

Note that the validate() method has to work out what the final Bayer
order of any raw streams will be, before configure() actually applies
the transform to the sensor. We make a note of the "native"
(untransformed) Bayer order when the system starts, so that we can
deduce transformed Bayer orders more easily.

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 143 insertions, 12 deletions

diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 36e38894..60f25864 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -23,6 +23,7 @@
 
 #include <linux/videodev2.h>
 
+#include "libcamera/internal/bayer_format.h"
 #include "libcamera/internal/camera_sensor.h"
 #include "libcamera/internal/device_enumerator.h"
 #include "libcamera/internal/ipa_manager.h"
@@ -133,6 +134,7 @@ class RPiCameraData : public CameraData
 public:
 	RPiCameraData(PipelineHandler *pipe)
 		: CameraData(pipe), sensor_(nullptr), state_(State::Stopped),
+		  supportsFlips_(false), flipsAlterBayerOrder_(false),
 		  dropFrameCount_(0), ispOutputCount_(0)
 	{
 	}
@@ -140,7 +142,7 @@ public:
 	void frameStarted(uint32_t sequence);
 
 	int loadIPA();
-	int configureIPA();
+	int configureIPA(const CameraConfiguration *config);
 
 	void queueFrameAction(unsigned int frame, const IPAOperationData &action);
 
@@ -182,6 +184,15 @@ public:
 	std::queue<FrameBuffer *> embeddedQueue_;
 	std::deque<Request *> requestQueue_;
 
+	/*
+	 * Manage horizontal and vertical flips supported (or not) by the
+	 * sensor. Also store the "native" Bayer order (that is, with no
+	 * transforms applied).
+	 */
+	bool supportsFlips_;
+	bool flipsAlterBayerOrder_;
+	BayerFormat::Order nativeBayerOrder_;
+
 	unsigned int dropFrameCount_;
 
 private:
@@ -201,6 +212,9 @@ public:
 
 	Status validate() override;
 
+	/* Cache the combinedTransform_ that will be applied to the sensor */
+	Transform combinedTransform_;
+
 private:
 	const RPiCameraData *data_;
 };
@@ -250,11 +264,61 @@ CameraConfiguration::Status RPiCameraConfiguration::validate()
 	if (config_.empty())
 		return Invalid;
 
-	if (transform != Transform::Identity) {
-		transform = Transform::Identity;
+	/*
+	 * What if the platform has a non-90 degree rotation? We can't even
+	 * "adjust" the configuration and carry on. Alternatively, raising an
+	 * error means the platform can never run. Let's just print a warning
+	 * and continue regardless; the rotation is effectively set to zero.
+	 */
+	int32_t rotation = data_->sensor_->properties().get(properties::Rotation);
+	bool success;
+	Transform rotationTransform = transformFromRotation(rotation, &success);
+	if (!success)
+		LOG(RPI, Warning) << "Invalid rotation of " << rotation
+				  << " degrees - ignoring";
+	Transform combined = transform * rotationTransform;
+
+	/*
+	 * We combine the platform and user transform, but must "adjust away"
+	 * any combined result that includes a transform, as we can't do those.
+	 * In this case, flipping only the transpose bit is helpful to
+	 * applications - they either get the transform they requested, or have
+	 * to do a simple transpose themselves (they don't have to worry about
+	 * the other possible cases).
+	 */
+	if (!!(combined & Transform::Transpose)) {
+		/*
+		 * Flipping the transpose bit in "transform" flips it in the
+		 * combined result too (as it's the last thing that happens),
+		 * which is of course clearing it.
+		 */
+		transform ^= Transform::Transpose;
+		combined &= ~Transform::Transpose;
+		status = Adjusted;
+	}
+
+	/*
+	 * We also check if the sensor doesn't do h/vflips at all, in which
+	 * case we clear them, and the application will have to do everything.
+	 */
+	if (!data_->supportsFlips_ && !!combined) {
+		/*
+		 * If the sensor can do no transforms, then combined must be
+		 * changed to the identity. The only user transform that gives
+		 * rise to this the inverse of the rotation. (Recall that
+		 * combined = transform * rotationTransform.)
+		 */
+		transform = -rotationTransform;
+		combined = Transform::Identity;
 		status = Adjusted;
 	}
 
+	/*
+	 * Store the final combined transform that configure() will need to
+	 * apply to the sensor to save us working it out again.
+	 */
+	combinedTransform_ = combined;
+
 	unsigned int rawCount = 0, outCount = 0, count = 0, maxIndex = 0;
 	std::pair<int, Size> outSize[2];
 	Size maxSize;
@@ -270,7 +334,23 @@ CameraConfiguration::Status RPiCameraConfiguration::validate()
 			if (ret)
 				return Invalid;
 
-			PixelFormat sensorPixFormat = sensorFormat.fourcc.toPixelFormat();
+			/*
+			 * Some sensors change their Bayer order when they are
+			 * h-flipped or v-flipped, according to the transform.
+			 * If this one does, we must advertise the transformed
+			 * Bayer order in the raw stream. Note how we must
+			 * fetch the "native" (i.e. untransformed) Bayer order,
+			 * because the sensor may currently be flipped!
+			 */
+			V4L2PixelFormat fourcc = sensorFormat.fourcc;
+			if (data_->flipsAlterBayerOrder_) {
+				BayerFormat bayer(fourcc);
+				bayer.order = data_->nativeBayerOrder_;
+				bayer = bayer.transform(combined);
+				fourcc = bayer.toV4L2PixelFormat();
+			}
+
+			PixelFormat sensorPixFormat = fourcc.toPixelFormat();
 			if (cfg.size != sensorFormat.size ||
 			    cfg.pixelFormat != sensorPixFormat) {
 				cfg.size = sensorFormat.size;
@@ -613,7 +693,7 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 	crop.y = (sensorFormat.size.height - crop.height) >> 1;
 	data->isp_[Isp::Input].dev()->setSelection(V4L2_SEL_TGT_CROP, &crop);
 
-	ret = data->configureIPA();
+	ret = data->configureIPA(config);
 	if (ret)
 		LOG(RPI, Error) << "Failed to configure the IPA: " << ret;
 
@@ -847,6 +927,47 @@ bool PipelineHandlerRPi::match(DeviceEnumerator *enumerator)
 	data->properties_ = data->sensor_->properties();
 
 	/*
+	 * We cache three things about the sensor in relation to transforms
+	 * (meaning horizontal and vertical flips).
+	 *
+	 * Firstly, does it support them?
+	 * Secondly, if you use them does it affect the Bayer ordering?
+	 * Thirdly, what is the "native" Bayer order, when no transforms are
+	 * applied?
+	 *
+	 * As part of answering the final question, we reset the camera to
+	 * no transform at all.
+	 */
+
+	V4L2VideoDevice *dev = data->unicam_[Unicam::Image].dev();
+	const struct v4l2_query_ext_ctrl *hflipCtrl = dev->controlInfo(V4L2_CID_HFLIP);
+	if (hflipCtrl) {
+		/* We assume it will support vflips too... */
+		data->supportsFlips_ = true;
+		data->flipsAlterBayerOrder_ = hflipCtrl->flags & V4L2_CTRL_FLAG_MODIFY_LAYOUT;
+
+		ControlList ctrls(dev->controls());
+		ctrls.set(V4L2_CID_HFLIP, 0);
+		ctrls.set(V4L2_CID_VFLIP, 0);
+		dev->setControls(&ctrls);
+	}
+
+	/* Look for a valid Bayer format. */
+	BayerFormat bayerFormat;
+	for (const auto &iter : dev->formats()) {
+		V4L2PixelFormat v4l2Format = iter.first;
+		bayerFormat = BayerFormat(v4l2Format);
+		if (bayerFormat.isValid())
+			break;
+	}
+
+	if (!bayerFormat.isValid()) {
+		LOG(RPI, Error) << "No Bayer format found";
+		return false;
+	}
+	data->nativeBayerOrder_ = bayerFormat.order;
+
+	/*
 	 * List the available streams an application may request. At present, we
 	 * do not advertise Unicam Embedded and ISP Statistics streams, as there
 	 * is no mechanism for the application to request non-image buffer formats.
@@ -985,8 +1106,12 @@ int RPiCameraData::loadIPA()
 	return ipa_->init(settings);
 }
 
-int RPiCameraData::configureIPA()
+int RPiCameraData::configureIPA(const CameraConfiguration *config)
 {
+	/* We know config must be an RPiCameraConfiguration. */
+	const RPiCameraConfiguration *rpiConfig =
+		static_cast<const RPiCameraConfiguration *>(config);
+
 	std::map<unsigned int, IPAStream> streamConfig;
 	std::map<unsigned int, const ControlInfoMap &> entityControls;
 	IPAOperationData ipaConfig = {};
@@ -1045,12 +1170,18 @@ int RPiCameraData::configureIPA()
 			sensorMetadata_ = result.data[resultIdx++];
 		}
 
-		/* Configure the H/V flip controls based on the sensor rotation. */
-		ControlList ctrls(unicam_[Unicam::Image].dev()->controls());
-		int32_t rotation = sensor_->properties().get(properties::Rotation);
-		ctrls.set(V4L2_CID_HFLIP, static_cast<int32_t>(!!rotation));
-		ctrls.set(V4L2_CID_VFLIP, static_cast<int32_t>(!!rotation));
-		unicam_[Unicam::Image].dev()->setControls(&ctrls);
+		/*
+		 * Configure the H/V flip controls based on the combination of
+		 * the sensor and user transform.
+		 */
+		if (supportsFlips_) {
+			ControlList ctrls(unicam_[Unicam::Image].dev()->controls());
+			ctrls.set(V4L2_CID_HFLIP,
+				  static_cast<int32_t>(!!(rpiConfig->combinedTransform_ & Transform::HFlip)));
+			ctrls.set(V4L2_CID_VFLIP,
+				  static_cast<int32_t>(!!(rpiConfig->combinedTransform_ & Transform::VFlip)));
+			unicam_[Unicam::Image].dev()->setControls(&ctrls);
+		}
 	}
 
 	if (result.operation & RPI_IPA_CONFIG_SENSOR) {