libcamera: pipeline: Add IMX8 ISI pipeline

Add a pipeline handler for the ISI capture interface found on
several versions of the i.MX8 SoC generation.

The pipeline handler supports capturing multiple streams from the same
camera in YUV, RGB or RAW formats. The number of streams is limited by
the number of ISI pipelines, and is currently hardcoded to 2 as the code
has been tested on the i.MX8MP only. Further development will make this
dynamic to support other SoCs.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

3 files changed, 956 insertions, 1 deletions

diff --git a/meson_options.txt b/meson_options.txt
index f1d67808..1ba6778c 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -37,7 +37,7 @@ option('lc-compliance',
 
 option('pipelines',
         type : 'array',
-        choices : ['ipu3', 'raspberrypi', 'rkisp1', 'simple', 'uvcvideo', 'vimc'],
+        choices : ['imx8-isi', 'ipu3', 'raspberrypi', 'rkisp1', 'simple', 'uvcvideo', 'vimc'],
         description : 'Select which pipeline handlers to include')
 
 option('qcam',
diff --git a/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp b/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
new file mode 100644
index 00000000..14d699b7
--- /dev/null
+++ b/src/libcamera/pipeline/imx8-isi/imx8-isi.cpp
@@ -0,0 +1,950 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2022 - Jacopo Mondi <jacopo@jmondi.org>
+ *
+ * imx8-isi.cpp - Pipeline handler for ISI interface found on NXP i.MX8 SoC
+ */
+
+#include <algorithm>
+#include <map>
+#include <memory>
+#include <set>
+#include <string>
+#include <vector>
+
+#include <libcamera/base/log.h>
+#include <libcamera/base/utils.h>
+
+#include <libcamera/camera_manager.h>
+#include <libcamera/formats.h>
+#include <libcamera/geometry.h>
+#include <libcamera/stream.h>
+
+#include "libcamera/internal/bayer_format.h"
+#include "libcamera/internal/camera.h"
+#include "libcamera/internal/camera_sensor.h"
+#include "libcamera/internal/device_enumerator.h"
+#include "libcamera/internal/media_device.h"
+#include "libcamera/internal/pipeline_handler.h"
+#include "libcamera/internal/v4l2_subdevice.h"
+#include "libcamera/internal/v4l2_videodevice.h"
+
+#include "linux/media-bus-format.h"
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(ISI)
+
+class PipelineHandlerISI;
+
+class ISICameraData : public Camera::Private
+{
+public:
+	ISICameraData(PipelineHandler *ph)
+		: Camera::Private(ph)
+	{
+		/*
+		 * \todo Assume 2 channels only for now, as that's the number of
+		 * available channels on i.MX8MP.
+		 */
+		streams_.resize(2);
+	}
+
+	PipelineHandlerISI *pipe();
+
+	int init();
+
+	unsigned int pipeIndex(const Stream *stream)
+	{
+		return stream - &*streams_.begin();
+	}
+
+	std::unique_ptr<CameraSensor> sensor_;
+	std::unique_ptr<V4L2Subdevice> csis_;
+
+	std::vector<Stream> streams_;
+
+	std::vector<Stream *> enabledStreams_;
+
+	unsigned int xbarSink_;
+};
+
+class ISICameraConfiguration : public CameraConfiguration
+{
+public:
+	/*
+	 * formatsMap_ records the association between an output pixel format
+	 * and the combination of V4L2 pixel format and media bus codes that have
+	 * to be applied to the pipeline.
+	 */
+	struct PipeFormat {
+		unsigned int isiCode;
+		unsigned int sensorCode;
+	};
+
+	using FormatMap = std::map<PixelFormat, PipeFormat>;
+
+	ISICameraConfiguration(ISICameraData *data)
+		: data_(data)
+	{
+	}
+
+	Status validate() override;
+
+	static const FormatMap formatsMap_;
+
+	V4L2SubdeviceFormat sensorFormat_;
+
+private:
+	CameraConfiguration::Status
+	validateRaw(std::set<Stream *> &availableStreams, const Size &maxResolution);
+	CameraConfiguration::Status
+	validateYuv(std::set<Stream *> &availableStreams, const Size &maxResolution);
+
+	const ISICameraData *data_;
+};
+
+class PipelineHandlerISI : public PipelineHandler
+{
+public:
+	PipelineHandlerISI(CameraManager *manager);
+
+	bool match(DeviceEnumerator *enumerator) override;
+
+	std::unique_ptr<CameraConfiguration>
+	generateConfiguration(Camera *camera, const StreamRoles &roles) override;
+	int configure(Camera *camera, CameraConfiguration *config) override;
+
+	int exportFrameBuffers(Camera *camera, Stream *stream,
+			       std::vector<std::unique_ptr<FrameBuffer>> *buffers) override;
+
+	int start(Camera *camera, const ControlList *controls) override;
+
+protected:
+	void stopDevice(Camera *camera) override;
+
+	int queueRequestDevice(Camera *camera, Request *request) override;
+
+private:
+	static constexpr Size kPreviewSize = { 1920, 1080 };
+	static constexpr Size kMinISISize = { 1, 1 };
+
+	struct Pipe {
+		std::unique_ptr<V4L2Subdevice> isi;
+		std::unique_ptr<V4L2VideoDevice> capture;
+	};
+
+	ISICameraData *cameraData(Camera *camera)
+	{
+		return static_cast<ISICameraData *>(camera->_d());
+	}
+
+	Pipe *pipeFromStream(Camera *camera, const Stream *stream);
+
+	void bufferReady(FrameBuffer *buffer);
+
+	MediaDevice *isiDev_;
+
+	std::unique_ptr<V4L2Subdevice> crossbar_;
+	std::vector<Pipe> pipes_;
+};
+
+/* -----------------------------------------------------------------------------
+ * Camera Data
+ */
+
+PipelineHandlerISI *ISICameraData::pipe()
+{
+	return static_cast<PipelineHandlerISI *>(Camera::Private::pipe());
+}
+
+/* Open and initialize pipe components. */
+int ISICameraData::init()
+{
+	int ret = sensor_->init();
+	if (ret)
+		return ret;
+
+	ret = csis_->open();
+	if (ret)
+		return ret;
+
+	properties_ = sensor_->properties();
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Camera Configuration
+ */
+
+/**
+ * \todo Do not associate the sensor format to non-RAW pixelformats, as
+ * the ISI can do colorspace conversion.
+ */
+const ISICameraConfiguration::FormatMap ISICameraConfiguration::formatsMap_ = {
+	{
+		formats::YUYV,
+		{ MEDIA_BUS_FMT_YUV8_1X24,
+		  MEDIA_BUS_FMT_UYVY8_1X16 },
+	},
+	{
+		formats::RGB565,
+		{ MEDIA_BUS_FMT_RGB888_1X24,
+		  MEDIA_BUS_FMT_RGB565_1X16 },
+	},
+	{
+		formats::SBGGR8,
+		{ MEDIA_BUS_FMT_SBGGR8_1X8,
+		  MEDIA_BUS_FMT_SBGGR8_1X8 },
+	},
+	{
+		formats::SGBRG8,
+		{ MEDIA_BUS_FMT_SGBRG8_1X8,
+		  MEDIA_BUS_FMT_SGBRG8_1X8 },
+	},
+	{
+		formats::SGRBG8,
+		{ MEDIA_BUS_FMT_SGRBG8_1X8,
+		  MEDIA_BUS_FMT_SGRBG8_1X8 },
+	},
+	{
+		formats::SRGGB8,
+		{ MEDIA_BUS_FMT_SRGGB8_1X8,
+		  MEDIA_BUS_FMT_SRGGB8_1X8 },
+	},
+	{
+		formats::SBGGR10,
+		{ MEDIA_BUS_FMT_SBGGR10_1X10,
+		  MEDIA_BUS_FMT_SBGGR10_1X10 },
+	},
+	{
+		formats::SGBRG10,
+		{ MEDIA_BUS_FMT_SGBRG10_1X10,
+		  MEDIA_BUS_FMT_SGBRG10_1X10 },
+	},
+	{
+		formats::SGRBG10,
+		{ MEDIA_BUS_FMT_SGRBG10_1X10,
+		  MEDIA_BUS_FMT_SGRBG10_1X10 },
+	},
+	{
+		formats::SRGGB10,
+		{ MEDIA_BUS_FMT_SRGGB10_1X10,
+		  MEDIA_BUS_FMT_SRGGB10_1X10 },
+	},
+	{
+		formats::SBGGR12,
+		{ MEDIA_BUS_FMT_SBGGR12_1X12,
+		  MEDIA_BUS_FMT_SBGGR12_1X12 },
+	},
+	{
+		formats::SGBRG12,
+		{ MEDIA_BUS_FMT_SGBRG12_1X12,
+		  MEDIA_BUS_FMT_SGBRG12_1X12 },
+	},
+	{
+		formats::SGRBG12,
+		{ MEDIA_BUS_FMT_SGRBG12_1X12,
+		  MEDIA_BUS_FMT_SGRBG12_1X12 },
+	},
+	{
+		formats::SRGGB12,
+		{ MEDIA_BUS_FMT_SRGGB12_1X12,
+		  MEDIA_BUS_FMT_SRGGB12_1X12 },
+	},
+};
+
+/*
+ * Adjust stream configuration when the first requested stream is RAW: all the
+ * streams will have the same RAW pixelformat and size.
+ */
+CameraConfiguration::Status
+ISICameraConfiguration::validateRaw(std::set<Stream *> &availableStreams,
+				    const Size &maxResolution)
+{
+	CameraConfiguration::Status status = Valid;
+
+	/*
+	 * Make sure the requested RAW format is supported by the
+	 * pipeline, otherwise adjust it.
+	 */
+	std::vector<unsigned int> mbusCodes = data_->sensor_->mbusCodes();
+	StreamConfiguration &rawConfig = config_[0];
+
+	bool supported = false;
+	auto it = formatsMap_.find(rawConfig.pixelFormat);
+	if (it != formatsMap_.end()) {
+		unsigned int mbusCode = it->second.sensorCode;
+
+		if (std::count(mbusCodes.begin(), mbusCodes.end(), mbusCode))
+			supported = true;
+	}
+
+	if (!supported) {
+		/*
+		 * Adjust to the first mbus code supported by both the
+		 * sensor and the pipeline.
+		 */
+		const FormatMap::value_type *pipeConfig = nullptr;
+		for (unsigned int code : mbusCodes) {
+			const BayerFormat &bayerFormat = BayerFormat::fromMbusCode(code);
+			if (!bayerFormat.isValid())
+				continue;
+
+			auto fmt = std::find_if(ISICameraConfiguration::formatsMap_.begin(),
+						ISICameraConfiguration::formatsMap_.end(),
+						[code](const auto &isiFormat) {
+							const auto &pipe = isiFormat.second;
+							return pipe.sensorCode == code;
+						});
+
+			if (fmt == ISICameraConfiguration::formatsMap_.end())
+				continue;
+
+			pipeConfig = &(*fmt);
+			break;
+		}
+
+		if (!pipeConfig) {
+			LOG(ISI, Error) << "Cannot adjust RAW format "
+					<< rawConfig.pixelFormat;
+			return Invalid;
+		}
+
+		rawConfig.pixelFormat = pipeConfig->first;
+		LOG(ISI, Debug) << "RAW pixelformat adjusted to "
+				<< pipeConfig->first;
+		status = Adjusted;
+	}
+
+	/* Cap the RAW stream size to the maximum resolution. */
+	const Size configSize = rawConfig.size;
+	rawConfig.size.boundTo(maxResolution);
+	if (rawConfig.size != configSize) {
+		LOG(ISI, Debug) << "RAW size adjusted to "
+				<< rawConfig.size;
+		status = Adjusted;
+	}
+
+	/* Adjust all other streams to RAW. */
+	for (const auto &[i, cfg] : utils::enumerate(config_)) {
+
+		LOG(ISI, Debug) << "Stream " << i << ": " << cfg.toString();
+		const PixelFormat pixFmt = cfg.pixelFormat;
+		const Size size = cfg.size;
+
+		cfg.pixelFormat = rawConfig.pixelFormat;
+		cfg.size = rawConfig.size;
+
+		if (cfg.pixelFormat != pixFmt || cfg.size != size) {
+			LOG(ISI, Debug) << "Stream " << i << " adjusted to "
+					<< cfg.toString();
+			status = Adjusted;
+		}
+
+		const PixelFormatInfo &info = PixelFormatInfo::info(cfg.pixelFormat);
+		cfg.stride = info.stride(cfg.size.width, 0);
+		cfg.frameSize = info.frameSize(cfg.size, info.bitsPerPixel);
+
+		/* Assign streams in the order they are presented. */
+		auto stream = availableStreams.extract(availableStreams.begin());
+		cfg.setStream(stream.value());
+	}
+
+	return status;
+}
+
+/*
+ * Adjust stream configuration when the first requested stream is not RAW: all
+ * the streams will be either YUV or RGB processed formats.
+ */
+CameraConfiguration::Status
+ISICameraConfiguration::validateYuv(std::set<Stream *> &availableStreams,
+				    const Size &maxResolution)
+{
+	CameraConfiguration::Status status = Valid;
+
+	for (const auto &[i, cfg] : utils::enumerate(config_)) {
+
+		LOG(ISI, Debug) << "Stream " << i << ": " << cfg.toString();
+
+		/* If the stream is RAW or not supported default it to YUYV. */
+		const PixelFormatInfo &cfgInfo = PixelFormatInfo::info(cfg.pixelFormat);
+		if (cfgInfo.colourEncoding == PixelFormatInfo::ColourEncodingRAW ||
+		    !formatsMap_.count(cfg.pixelFormat)) {
+
+			LOG(ISI, Debug) << "Stream " << i << " format: "
+					<< cfg.pixelFormat << " adjusted to YUYV";
+
+			cfg.pixelFormat = formats::YUYV;
+			status = Adjusted;
+		}
+
+		/* Cap the streams size to the maximum accepted resolution. */
+		Size configSize = cfg.size;
+		cfg.size.boundTo(maxResolution);
+		if (cfg.size != configSize) {
+			LOG(ISI, Debug)
+				<< "Stream " << i << " adjusted to " << cfg.size;
+			status = Adjusted;
+		}
+
+		/* Re-fetch the pixel format info in case it has been adjusted. */
+		const PixelFormatInfo &info = PixelFormatInfo::info(cfg.pixelFormat);
+
+		/* \todo Multiplane ? */
+		cfg.stride = info.stride(cfg.size.width, 0);
+		cfg.frameSize = info.frameSize(cfg.size, info.bitsPerPixel);
+
+		/* Assign streams in the order they are presented. */
+		auto stream = availableStreams.extract(availableStreams.begin());
+		cfg.setStream(stream.value());
+	}
+
+	return status;
+}
+
+CameraConfiguration::Status ISICameraConfiguration::validate()
+{
+	Status status = Valid;
+
+	std::set<Stream *> availableStreams;
+	std::transform(data_->streams_.begin(), data_->streams_.end(),
+		       std::inserter(availableStreams, availableStreams.end()),
+		       [](const Stream &s) { return const_cast<Stream *>(&s); });
+
+	if (config_.empty())
+		return Invalid;
+
+	/* Cap the number of streams to the number of available ISI pipes. */
+	if (config_.size() > availableStreams.size()) {
+		config_.resize(availableStreams.size());
+		status = Adjusted;
+	}
+
+	/*
+	 * If more than a single stream is requested, the maximum allowed input
+	 * image width is 2048. Cap the maximum image size accordingly.
+	 *
+	 * \todo The (size > 1) check only applies to i.MX8MP which has 2 ISI
+	 * channels. SoCs with more channels than the i.MX8MP are capable of
+	 * supporting more streams with input width > 2048 by chaining
+	 * successive channels together. Define a policy for channels allocation
+	 * to fully support other SoCs.
+	 */
+	CameraSensor *sensor = data_->sensor_.get();
+	Size maxResolution = sensor->resolution();
+	if (config_.size() > 1)
+		maxResolution.width = std::min(2048U, maxResolution.width);
+
+	/* Validate streams according to the format of the first one. */
+	const PixelFormatInfo info = PixelFormatInfo::info(config_[0].pixelFormat);
+
+	Status validationStatus;
+	if (info.colourEncoding == PixelFormatInfo::ColourEncodingRAW)
+		validationStatus = validateRaw(availableStreams, maxResolution);
+	else
+		validationStatus = validateYuv(availableStreams, maxResolution);
+
+	if (validationStatus == Invalid)
+		return Invalid;
+
+	if (validationStatus == Adjusted)
+		status = Adjusted;
+
+	/*
+	 * Sensor format selection policy: the first stream selects the media
+	 * bus code to use, the largest stream selects the size.
+	 *
+	 * \todo The sensor format selection policy could be changed to
+	 * prefer operating the sensor at full resolution to prioritize
+	 * image quality in exchange of a usually slower frame rate.
+	 * Usage of the STILL_CAPTURE role could be consider for this.
+	 */
+	const PipeFormat &pipeFmt = formatsMap_.at(config_[0].pixelFormat);
+
+	Size maxSize;
+	for (const auto &cfg : config_) {
+		if (cfg.size > maxSize)
+			maxSize = cfg.size;
+	}
+
+	V4L2SubdeviceFormat sensorFormat{};
+	sensorFormat.mbus_code = pipeFmt.sensorCode;
+	sensorFormat.size = maxSize;
+
+	LOG(ISI, Debug) << "Computed sensor configuration: " << sensorFormat;
+
+	/*
+	 * We can't use CameraSensor::getFormat() as it might return a
+	 * format larger than our strict width limit, as that function
+	 * prioritizes formats with the same aspect ratio over formats with less
+	 * difference in size.
+	 *
+	 * Manually walk all the sensor supported sizes searching for
+	 * the smallest larger format without considering the aspect ratio
+	 * as the ISI can freely scale.
+	 */
+	auto sizes = sensor->sizes(sensorFormat.mbus_code);
+	Size bestSize;
+
+	for (const Size &s : sizes) {
+		/* Ignore smaller sizes. */
+		if (s.width < sensorFormat.size.width ||
+		    s.height < sensorFormat.size.height)
+			continue;
+
+		/* Make sure the width stays in the limits. */
+		if (s.width > maxResolution.width)
+			continue;
+
+		bestSize = s;
+		break;
+	}
+
+	/*
+	 * This should happen only if the sensor can only produce formats that
+	 * exceed the maximum allowed input width.
+	 */
+	if (bestSize.isNull()) {
+		LOG(ISI, Error) << "Unable to find a suitable sensor format";
+		return Invalid;
+	}
+
+	sensorFormat_.mbus_code = sensorFormat.mbus_code;
+	sensorFormat_.size = bestSize;
+
+	LOG(ISI, Debug) << "Selected sensor format: " << sensorFormat_;
+
+	return status;
+}
+
+/* -----------------------------------------------------------------------------
+ * Pipeline Handler
+ */
+
+PipelineHandlerISI::PipelineHandlerISI(CameraManager *manager)
+	: PipelineHandler(manager)
+{
+}
+
+std::unique_ptr<CameraConfiguration>
+PipelineHandlerISI::generateConfiguration(Camera *camera,
+					  const StreamRoles &roles)
+{
+	ISICameraData *data = cameraData(camera);
+	std::unique_ptr<ISICameraConfiguration> config =
+		std::make_unique<ISICameraConfiguration>(data);
+
+	if (roles.empty())
+		return config;
+
+	if (roles.size() > data->streams_.size()) {
+		LOG(ISI, Error) << "Only up to " << data->streams_.size()
+				<< " streams are supported";
+		return nullptr;
+	}
+
+	for (const auto &role : roles) {
+		/*
+		 * Prefer the following formats
+		 * - Still Capture: Full resolution YUYV
+		 * - ViewFinder/VideoRecording: 1080p YUYV
+		 * - RAW: sensor's native format and resolution
+		 */
+		PixelFormat pixelFormat;
+		Size size;
+
+		switch (role) {
+		case StillCapture:
+			/*
+			 * \todo Make sure the sensor can produce non-RAW formats
+			 * compatible with the ones supported by the pipeline.
+			 */
+			size = data->sensor_->resolution();
+			pixelFormat = formats::YUYV;
+			break;
+
+		case Viewfinder:
+		case VideoRecording:
+			/*
+			 * \todo Make sure the sensor can produce non-RAW formats
+			 * compatible with the ones supported by the pipeline.
+			 */
+			size = PipelineHandlerISI::kPreviewSize;
+			pixelFormat = formats::YUYV;
+			break;
+
+		case Raw: {
+			/*
+			 * Make sure the sensor can generate a RAW format and
+			 * prefer the ones with a larger bitdepth.
+			 */
+			const ISICameraConfiguration::FormatMap::value_type *rawPipeFormat = nullptr;
+			unsigned int maxDepth = 0;
+
+			for (unsigned int code : data->sensor_->mbusCodes()) {
+				const BayerFormat &bayerFormat = BayerFormat::fromMbusCode(code);
+				if (!bayerFormat.isValid())
+					continue;
+
+				/* Make sure the format is supported by the pipeline handler. */
+				auto it = std::find_if(ISICameraConfiguration::formatsMap_.begin(),
+						       ISICameraConfiguration::formatsMap_.end(),
+						       [code](auto &isiFormat) {
+							        auto &pipe = isiFormat.second;
+							        return pipe.sensorCode == code;
+						       });
+				if (it == ISICameraConfiguration::formatsMap_.end())
+					continue;
+
+				if (bayerFormat.bitDepth > maxDepth) {
+					maxDepth = bayerFormat.bitDepth;
+					rawPipeFormat = &(*it);
+				}
+			}
+
+			if (!rawPipeFormat) {
+				LOG(ISI, Error)
+					<< "Cannot generate a configuration for RAW stream";
+				return nullptr;
+			}
+
+			size = data->sensor_->resolution();
+			pixelFormat = rawPipeFormat->first;
+
+			break;
+		}
+
+		default:
+			LOG(ISI, Error) << "Requested stream role not supported: " << role;
+			return nullptr;
+		}
+
+		/* \todo Add all supported formats. */
+		std::map<PixelFormat, std::vector<SizeRange>> streamFormats;
+		streamFormats[pixelFormat] = { { kMinISISize, size } };
+		StreamFormats formats(streamFormats);
+
+		StreamConfiguration cfg(formats);
+		cfg.pixelFormat = pixelFormat;
+		cfg.size = size;
+		cfg.bufferCount = 4;
+		config->addConfiguration(cfg);
+	}
+
+	config->validate();
+
+	return config;
+}
+
+int PipelineHandlerISI::configure(Camera *camera, CameraConfiguration *c)
+{
+	ISICameraConfiguration *camConfig = static_cast<ISICameraConfiguration *>(c);
+	ISICameraData *data = cameraData(camera);
+
+	/* All links are immutable except the sensor -> csis link. */
+	const MediaPad *sensorSrc = data->sensor_->entity()->getPadByIndex(0);
+	sensorSrc->links()[0]->setEnabled(true);
+
+	/*
+	 * Reset the crossbar switch routing and enable one route for each
+	 * requested stream configuration.
+	 *
+	 * \todo Handle concurrent usage of multiple cameras by adjusting the
+	 * routing table instead of resetting it.
+	 */
+	V4L2Subdevice::Routing routing = {};
+	unsigned int xbarFirstSource = crossbar_->entity()->pads().size() / 2 + 1;
+
+	for (const auto &[idx, config] : utils::enumerate(*c)) {
+		struct v4l2_subdev_route route = {
+			.sink_pad = data->xbarSink_,
+			.sink_stream = 0,
+			.source_pad = static_cast<uint32_t>(xbarFirstSource + idx),
+			.source_stream = 0,
+			.flags = V4L2_SUBDEV_ROUTE_FL_ACTIVE,
+			.reserved = {}
+		};
+
+		routing.push_back(route);
+	}
+
+	int ret = crossbar_->setRouting(&routing, V4L2Subdevice::ActiveFormat);
+	if (ret)
+		return ret;
+
+	/* Apply format to the sensor and CSIS receiver. */
+	V4L2SubdeviceFormat format = camConfig->sensorFormat_;
+	ret = data->sensor_->setFormat(&format);
+	if (ret)
+		return ret;
+
+	ret = data->csis_->setFormat(0, &format);
+	if (ret)
+		return ret;
+
+	ret = crossbar_->setFormat(data->xbarSink_, &format);
+	if (ret)
+		return ret;
+
+	/* Now configure the ISI and video node instances, one per stream. */
+	data->enabledStreams_.clear();
+	for (const auto &config : *c) {
+		Pipe *pipe = pipeFromStream(camera, config.stream());
+
+		/*
+		 * Set the format on the ISI sink pad: it must match what is
+		 * received by the CSIS.
+		 */
+		ret = pipe->isi->setFormat(0, &format);
+		if (ret)
+			return ret;
+
+		/*
+		 * Configure the ISI sink compose rectangle to downscale the
+		 * image.
+		 *
+		 * \todo Additional cropping could be applied on the ISI source
+		 * pad to further reduce the output image size.
+		 */
+		Rectangle isiScale(config.size);
+		ret = pipe->isi->setSelection(0, V4L2_SEL_TGT_COMPOSE, &isiScale);
+		if (ret)
+			return ret;
+
+		/*
+		 * Set the format on ISI source pad: only the media bus code
+		 * is relevant as it configures format conversion, while the
+		 * size is taken from the sink's COMPOSE (or source's CROP,
+		 * if any) rectangles.
+		 */
+		const ISICameraConfiguration::PipeFormat &pipeFormat =
+			ISICameraConfiguration::formatsMap_.at(config.pixelFormat);
+
+		V4L2SubdeviceFormat isiFormat{};
+		isiFormat.mbus_code = pipeFormat.isiCode;
+		isiFormat.size = config.size;
+
+		ret = pipe->isi->setFormat(1, &isiFormat);
+		if (ret)
+			return ret;
+
+		V4L2DeviceFormat captureFmt{};
+		captureFmt.fourcc = pipe->capture->toV4L2PixelFormat(config.pixelFormat);
+		captureFmt.size = config.size;
+
+		/* \todo Set stride and format. */
+		ret = pipe->capture->setFormat(&captureFmt);
+		if (ret)
+			return ret;
+
+		/* Store the list of enabled streams for later use. */
+		data->enabledStreams_.push_back(config.stream());
+	}
+
+	return 0;
+}
+
+int PipelineHandlerISI::exportFrameBuffers(Camera *camera, Stream *stream,
+					   std::vector<std::unique_ptr<FrameBuffer>> *buffers)
+{
+	unsigned int count = stream->configuration().bufferCount;
+	Pipe *pipe = pipeFromStream(camera, stream);
+
+	return pipe->capture->exportBuffers(count, buffers);
+}
+
+int PipelineHandlerISI::start(Camera *camera,
+			      [[maybe_unused]] const ControlList *controls)
+{
+	ISICameraData *data = cameraData(camera);
+
+	for (const auto &stream : data->enabledStreams_) {
+		Pipe *pipe = pipeFromStream(camera, stream);
+		const StreamConfiguration &config = stream->configuration();
+
+		int ret = pipe->capture->importBuffers(config.bufferCount);
+		if (ret)
+			return ret;
+
+		ret = pipe->capture->streamOn();
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+void PipelineHandlerISI::stopDevice(Camera *camera)
+{
+	ISICameraData *data = cameraData(camera);
+
+	for (const auto &stream : data->enabledStreams_) {
+		Pipe *pipe = pipeFromStream(camera, stream);
+
+		pipe->capture->streamOff();
+		pipe->capture->releaseBuffers();
+	}
+}
+
+int PipelineHandlerISI::queueRequestDevice(Camera *camera, Request *request)
+{
+	for (auto &[stream, buffer] : request->buffers()) {
+		Pipe *pipe = pipeFromStream(camera, stream);
+
+		int ret = pipe->capture->queueBuffer(buffer);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+bool PipelineHandlerISI::match(DeviceEnumerator *enumerator)
+{
+	DeviceMatch dm("mxc-isi");
+	dm.add("crossbar");
+	dm.add("mxc_isi.0");
+	dm.add("mxc_isi.0.capture");
+
+	isiDev_ = acquireMediaDevice(enumerator, dm);
+	if (!isiDev_)
+		return false;
+
+	/*
+	 * Acquire the subdevs and video nodes for the crossbar switch and the
+	 * processing pipelines.
+	 */
+	crossbar_ = V4L2Subdevice::fromEntityName(isiDev_, "crossbar");
+	if (!crossbar_)
+		return false;
+
+	int ret = crossbar_->open();
+	if (ret)
+		return false;
+
+	for (unsigned int i = 0; ; ++i) {
+		std::string entityName = "mxc_isi." + std::to_string(i);
+		std::unique_ptr<V4L2Subdevice> isi =
+			V4L2Subdevice::fromEntityName(isiDev_, entityName);
+		if (!isi)
+			break;
+
+		ret = isi->open();
+		if (ret)
+			return false;
+
+		entityName += ".capture";
+		std::unique_ptr<V4L2VideoDevice> capture =
+			V4L2VideoDevice::fromEntityName(isiDev_, entityName);
+		if (!capture)
+			return false;
+
+		capture->bufferReady.connect(this, &PipelineHandlerISI::bufferReady);
+
+		ret = capture->open();
+		if (ret)
+			return ret;
+
+		pipes_.push_back({ std::move(isi), std::move(capture) });
+	}
+
+	if (pipes_.empty()) {
+		LOG(ISI, Error) << "Unable to enumerate pipes";
+		return false;
+	}
+
+	/*
+	 * Loop over all the crossbar switch sink pads to find connected CSI-2
+	 * receivers and camera sensors.
+	 */
+	unsigned int numCameras = 0;
+	unsigned int numSinks = 0;
+	for (MediaPad *pad : crossbar_->entity()->pads()) {
+		unsigned int sink = numSinks;
+
+		if (!(pad->flags() & MEDIA_PAD_FL_SINK) || pad->links().empty())
+			continue;
+
+		/*
+		 * Count each crossbar sink pad to correctly configure
+		 * routing and format for this camera.
+		 */
+		numSinks++;
+
+		MediaEntity *csi = pad->links()[0]->source()->entity();
+		if (csi->pads().size() != 2) {
+			LOG(ISI, Debug) << "Skip unsupported CSI-2 receiver "
+					<< csi->name();
+			continue;
+		}
+
+		pad = csi->pads()[0];
+		if (!(pad->flags() & MEDIA_PAD_FL_SINK) || pad->links().empty())
+			continue;
+
+		MediaEntity *sensor = pad->links()[0]->source()->entity();
+		if (sensor->function() != MEDIA_ENT_F_CAM_SENSOR) {
+			LOG(ISI, Debug) << "Skip unsupported subdevice "
+					<< sensor->name();
+			continue;
+		}
+
+		/* Create the camera data. */
+		std::unique_ptr<ISICameraData> data =
+			std::make_unique<ISICameraData>(this);
+
+		data->sensor_ = std::make_unique<CameraSensor>(sensor);
+		data->csis_ = std::make_unique<V4L2Subdevice>(csi);
+		data->xbarSink_ = sink;
+
+		ret = data->init();
+		if (ret) {
+			LOG(ISI, Error) << "Failed to initialize camera data";
+			return false;
+		}
+
+		/* Register the camera. */
+		const std::string &id = data->sensor_->id();
+		std::set<Stream *> streams;
+		std::transform(data->streams_.begin(), data->streams_.end(),
+			       std::inserter(streams, streams.end()),
+			       [](Stream &s) { return &s; });
+
+		std::shared_ptr<Camera> camera =
+			Camera::create(std::move(data), id, streams);
+
+		registerCamera(std::move(camera));
+		numCameras++;
+	}
+
+	return numCameras > 0;
+}
+
+PipelineHandlerISI::Pipe *PipelineHandlerISI::pipeFromStream(Camera *camera,
+							     const Stream *stream)
+{
+	ISICameraData *data = cameraData(camera);
+	unsigned int pipeIndex = data->pipeIndex(stream);
+
+	ASSERT(pipeIndex < pipes_.size());
+
+	return &pipes_[pipeIndex];
+}
+
+void PipelineHandlerISI::bufferReady(FrameBuffer *buffer)
+{
+	Request *request = buffer->request();
+
+	completeBuffer(request, buffer);
+	if (request->hasPendingBuffers())
+		return;
+
+	completeRequest(request);
+}
+
+REGISTER_PIPELINE_HANDLER(PipelineHandlerISI)
+
+} /* namespace libcamera */
diff --git a/src/libcamera/pipeline/imx8-isi/meson.build b/src/libcamera/pipeline/imx8-isi/meson.build
new file mode 100644
index 00000000..ffd0ce54
--- /dev/null
+++ b/src/libcamera/pipeline/imx8-isi/meson.build
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: CC0-1.0
+
+libcamera_sources += files([
+    'imx8-isi.cpp'
+])