[{"id":27665,"web_url":"https://patchwork.libcamera.org/comment/27665/","msgid":"<169222123253.695434.10047930417440014774@ping.linuxembedded.co.uk>","date":"2023-08-16T21:27:12","subject":"Re: [libcamera-devel] [RFC PATCH 4/5] libcamera: pipeline:\n\tuvcvideo: Allocate metadata buffers","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Quoting Gabby George (2023-08-14 12:28:48)\n> Perform the allocation and mapping of metadata buffers into\n> libcamera's virtual address space. UVC metadata buffers cannot be\n> exported as DMA buffer file descriptors, so use the MappedFrameBuffer\n> class to map them into memory directly. This will give the UVC\n> pipeline access to buffer data to extract timestamp information.\n> \n> Metadata buffers are internal to the UVC pipeline, so buffer memory\n> should not be exposed to the user.\n\nSounds reasonable.\n\n\n> \n> Signed-off-by: Gabby George \n> ---\n> src/libcamera/pipeline/uvcvideo/uvcvideo.cpp | 97 +++++++++++++++++++-\n> 1 file changed, 95 insertions(+), 2 deletions(-)\n> \n> diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp\n> index 4470d8a2..51f30187 100644\n> --- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp\n> +++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp\n> @@ -24,6 +24,7 @@\n> \n> #include \"libcamera/internal/camera.h\"\n> #include \"libcamera/internal/device_enumerator.h\"\n> +#include \"libcamera/internal/mapped_framebuffer.h\"\n> #include \"libcamera/internal/media_device.h\"\n> #include \"libcamera/internal/pipeline_handler.h\"\n> #include \"libcamera/internal/sysfs.h\"\n> @@ -51,11 +52,17 @@ public:\n> std::unique_ptr video_;\n> std::unique_ptr metadata_;\n> Stream stream_;\n> + std::vector> metadataBuffers_;\n> + std::map mappedMetadataBuffers_;\n> + bool useMetadataStream_;\n\nI wonder if we'll need this bool. Just from reading these 6 lines, I\ncould probably assume we could replace anything that has \n\tif (useMoetadataStream_)\nwith\n\tif (metadata_)\n\n\n\n> +\n> std::map> formats_;\n> \n> private:\n> int initMetadata(MediaDevice *media);\n> \n> + const unsigned int minLengthHeaderBuf_ = 10;\n> +\n> bool generateId();\n> \n> std::string id_;\n> @@ -96,6 +103,10 @@ private:\n> const ControlValue &value);\n> int processControls(UVCCameraData *data, Request *request);\n> \n> + int createMetadataBuffers(Camera *camera, unsigned int count);\n> + int cleanupMetadataBuffers(Camera *camera);\n> + int cleanup(Camera *camera);\n> +\n> UVCCameraData *cameraData(Camera *camera)\n> {\n> return static_cast(camera->_d());\n> @@ -225,10 +236,66 @@ int PipelineHandlerUVC::configure(Camera *camera, CameraConfiguration *config)\n> return -EINVAL;\n> \n> cfg.setStream(&data->stream_);\n> + return 0;\n> +}\n> \n> +int PipelineHandlerUVC::cleanupMetadataBuffers(Camera *camera)\n> +{\n> + int ret = 0;\n> + UVCCameraData *data = cameraData(camera);\n> +\n> + ret = data->metadata_->releaseBuffers();\n> + data->metadataBuffers_.clear(); //call the destructor for the frame buffers\n\nI think we can remove the comment on that line.\n\n> + data->mappedMetadataBuffers_.clear();\n> + data->useMetadataStream_ = false;\n> +\n> + return ret;\n> +}\n> +\n> +int PipelineHandlerUVC::cleanup(Camera *camera)\n> +{\n> + UVCCameraData *data = cameraData(camera);\n> + cleanupMetadataBuffers(camera);\n> + data->video_->releaseBuffers();\n> return 0;\n> }\n> \n> +/*\n\nOpen a block comment with\n \t/**\n\nif it's a documentation comment for doxygen.\n\n\n> + * UVC Metadata stream does not support exporting buffers via EXPBUF,\n> + * so it is necessary to create and store mmap-ed addresses.\n> + * Metadata buffers are internal to libcamera. They are not, and\n> + * cannot be, exposed to the user.\n> + *\n> + * Returns the number of buffers allocated and mapped.\n> + *\n> + * \\return The number of buffers allocated, or a negative error code if\n> + * the number of buffers allocated was not equal to \"count\"\n> + * \\retval -EINVAL if \"count\" buffers were not successfully allocated.\n> + * \\retval -ENOMEM if mmap failed.\n\nHrm ... Have you checked if this is what MappedFrameBuffer.error() will\nreturn? Maybe this should refer to saying 'MappedFrameBuffer::error()'\nif the Frame could not be mapped successfully ...\n\n> + */\n> +int PipelineHandlerUVC::createMetadataBuffers(Camera *camera, unsigned int count)\n> +{\n> + UVCCameraData *data = cameraData(camera);\n> + int ret = data->metadata_->allocateBuffers(count, &data->metadataBuffers_);\n> + if (ret < 0)\n> + return -EINVAL;\n> +\n> + for (unsigned int i = 0; i < count; i++) {\n> + MappedFrameBuffer mappedBuffer(data->metadataBuffers_[i].get(),\n> + MappedFrameBuffer::MapFlag::Read, true);\n> + if (!mappedBuffer.isValid()) {\n> + LOG(UVC, Error)\n> + << \"Failed to mmap metadata buffer: \"\n> + << strerror(mappedBuffer.error());\n> + return mappedBuffer.error();\n> + }\n> +\n> + data->mappedMetadataBuffers_.emplace(i, std::move(mappedBuffer));\n> + data->metadataBuffers_[i]->setCookie(i);\n> + }\n> + return ret;\n> +}\n> +\n> int PipelineHandlerUVC::exportFrameBuffers(Camera *camera, Stream *stream,\n> std::vector> *buffers)\n> {\n> @@ -247,20 +314,46 @@ int PipelineHandlerUVC::start(Camera *camera, [[maybe_unused]] const ControlList\n> if (ret < 0)\n> return ret;\n> \n> + if (data->useMetadataStream_) {\n> + if (createMetadataBuffers(camera, count) < 0) {\n> + LOG(UVC, Error) << \"Unable to allocate buffers for UVC metadata stream.\";\n> + data->useMetadataStream_ = false;\n> + }\n> + }\n> +\n> ret = data->video_->streamOn();\n> if (ret < 0) {\n> - data->video_->releaseBuffers();\n> + cleanup(camera);\n> return ret;\n> }\n> \n> + if (data->useMetadataStream_) {\n> + ret = data->metadata_->streamOn();\n> + if (ret) {\n> + LOG(UVC, Error) << \"Failed to start metadata stream\";\n> + return ret;\n> + }\n> +\n> + for (std::unique_ptr &buf : data->metadataBuffers_) {\n> + ret = data->metadata_->queueBuffer(buf.get());\n> + if (ret < 0) {\n> + cleanupMetadataBuffers(camera);\n> + return ret;\n> + }\n> + }\n\nCan all of this be done before video_->streamOn() to avoid having two\nconditionals that check if we useMetadataStream_ ?\n\n\n> + }\n> return 0;\n> }\n> \n> void PipelineHandlerUVC::stopDevice(Camera *camera)\n> {\n> UVCCameraData *data = cameraData(camera);\n> +\n> data->video_->streamOff();\n> - data->video_->releaseBuffers();\n> +\n> + data->metadata_->streamOff();\n> +\n> + cleanup(camera);\n> }\n> \n> int PipelineHandlerUVC::processControl(ControlList *controls, unsigned int id,\n> -- \n> 2.34.1\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 53220BE08A\n\tfor ;\n\tWed, 16 Aug 2023 21:27:18 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id AD5DA628D8;\n\tWed, 16 Aug 2023 23:27:17 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 20D94628D3\n\tfor ;\n\tWed, 16 Aug 2023 23:27:16 +0200 (CEST)","from pendragon.ideasonboard.com\n\t(aztw-30-b2-v4wan-166917-cust845.vm26.cable.virginm.net\n\t[82.37.23.78])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 9CC6F2CF;\n\tWed, 16 Aug 2023 23:26:02 +0200 (CEST)"],"DKIM-Signature":["v=1; 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