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{ "id": 13238, "url": "https://patchwork.libcamera.org/api/1.1/patches/13238/?format=api", "web_url": "https://patchwork.libcamera.org/patch/13238/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/1.1/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20210805222436.6263-8-laurent.pinchart@ideasonboard.com>", "date": "2021-08-05T22:24:33", "name": "[libcamera-devel,07/10] libcamera: pipeline: simple: Add pipeline pad reservation mechanism", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": false, "hash": "35fd4de416288f012e8d4745bb7fcd234212e626", "submitter": { "id": 2, "url": "https://patchwork.libcamera.org/api/1.1/people/2/?format=api", "name": "Laurent Pinchart", "email": "laurent.pinchart@ideasonboard.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/13238/mbox/", "series": [ { "id": 2314, "url": "https://patchwork.libcamera.org/api/1.1/series/2314/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=2314", "date": "2021-08-05T22:24:26", "name": "Concurrent camera support in simple pipeline handler", "version": 1, "mbox": "https://patchwork.libcamera.org/series/2314/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/13238/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/13238/checks/", "tags": {}, "headers": { "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>", "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 1C1EFC323C\n\tfor <parsemail@patchwork.libcamera.org>;\n\tThu, 5 Aug 2021 22:25:04 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 073D0688CA;\n\tFri, 6 Aug 2021 00:25:02 +0200 (CEST)", "from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 127186884E\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tFri, 6 Aug 2021 00:24:58 +0200 (CEST)", "from pendragon.lan (62-78-145-57.bb.dnainternet.fi [62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id AF7DE4FB\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tFri, 6 Aug 2021 00:24:57 +0200 (CEST)" ], "Authentication-Results": "lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"kwEcaz9A\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1628202297;\n\tbh=yLlL0DLW9bNfQFknGVf71ywNPPHIqC9SNrVsLNOSPlE=;\n\th=From:To:Subject:Date:In-Reply-To:References:From;\n\tb=kwEcaz9AjdHgHb2J3Ajr3UhbyNK29Hj/VgIzkzniKeDnmNRVd9vSfya4DYJVbBYEY\n\tdRkat+FoMs4tLr2kZb9s0vcGwUzVdFSk88olw5UbRvhpbmDCO1jcPaq/zWeGhqnMvA\n\tQx861dVKFq0rnzu71x2uXYAt+efbSRSZHCNjvt0k=", "From": "Laurent Pinchart <laurent.pinchart@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Date": "Fri, 6 Aug 2021 01:24:33 +0300", "Message-Id": "<20210805222436.6263-8-laurent.pinchart@ideasonboard.com>", "X-Mailer": "git-send-email 2.31.1", "In-Reply-To": "<20210805222436.6263-1-laurent.pinchart@ideasonboard.com>", "References": "<20210805222436.6263-1-laurent.pinchart@ideasonboard.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "Subject": "[libcamera-devel] [PATCH 07/10] libcamera: pipeline: simple: Add\n\tpipeline pad reservation mechanism", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "content": "The cameras created by the same pipeline handler instance may share\nhardware resources, prohibiting usage of multiple cameras concurrently.\nImplement a heuristic to reserve resources and handle mutual exclusiong\nin a generic way.\n\nSigned-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>\n---\n src/libcamera/pipeline/simple/simple.cpp | 95 +++++++++++++++++++++++-\n 1 file changed, 93 insertions(+), 2 deletions(-)", "diff": "diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp\nindex 17ef3f43ad41..b32369cae701 100644\n--- a/src/libcamera/pipeline/simple/simple.cpp\n+++ b/src/libcamera/pipeline/simple/simple.cpp\n@@ -121,6 +121,28 @@ LOG_DEFINE_CATEGORY(SimplePipeline)\n * the pixel formats and sizes that the converter can produce for the output of\n * the capture video node, and stores the information in the outputFormats and\n * outputSizes of the SimpleCameraData::Configuration structure.\n+ *\n+ * Concurrent Access to Cameras\n+ * ----------------------------\n+ *\n+ * The cameras created by the same pipeline handler instance may share hardware\n+ * resources. For instances, a platform may have multiple CSI-2 receivers but a\n+ * single DMA engine, prohibiting usage of multiple cameras concurrently. This\n+ * depends heavily on the hardware architecture, which the simple pipeline\n+ * handler has no a priori knowledge of. The pipeline handler thus implements a\n+ * heuristic to handle sharing of hardware resources in a generic fashion.\n+ *\n+ * Two cameras are considered to be mutually exclusive if their share common\n+ * pads along the pipeline from the camera sensor to the video node. An entity\n+ * can thus be used concurrently by multiple cameras, as long as pads are\n+ * distinct.\n+ *\n+ * A resource reservation mechanism is implemented by the SimplePipelineHandler\n+ * acquirePipeline() and releasePipeline() functions to manage exclusive access\n+ * to pads. A camera reserves all the pads present in its pipeline when it is\n+ * started, and the start() function returns an error if any of the required\n+ * pads is already in use. When the camera is stopped, the pads it has reserved\n+ * are released.\n */\n \n class SimplePipelineHandler;\n@@ -266,6 +288,7 @@ private:\n \tstruct EntityData {\n \t\tstd::unique_ptr<V4L2VideoDevice> video;\n \t\tstd::unique_ptr<V4L2Subdevice> subdev;\n+\t\tstd::map<const MediaPad *, SimpleCameraData *> owners;\n \t};\n \n \tSimpleCameraData *cameraData(const Camera *camera)\n@@ -276,6 +299,9 @@ private:\n \n \tstd::vector<MediaEntity *> locateSensors();\n \n+\tconst MediaPad *acquirePipeline(SimpleCameraData *data);\n+\tvoid releasePipeline(SimpleCameraData *data);\n+\n \tvoid bufferReady(FrameBuffer *buffer);\n \tvoid converterInputDone(FrameBuffer *buffer);\n \tvoid converterOutputDone(FrameBuffer *buffer);\n@@ -841,6 +867,14 @@ int SimplePipelineHandler::start(Camera *camera, [[maybe_unused]] const ControlL\n \tV4L2VideoDevice *video = data->video_;\n \tint ret;\n \n+\tconst MediaPad *pad = acquirePipeline(data);\n+\tif (pad) {\n+\t\tLOG(SimplePipeline, Info)\n+\t\t\t<< \"Failed to acquire pipeline, entity \"\n+\t\t\t<< pad->entity()->name() << \" in use\";\n+\t\treturn -EBUSY;\n+\t}\n+\n \tif (data->useConverter_) {\n \t\t/*\n \t\t * When using the converter allocate a fixed number of internal\n@@ -853,8 +887,10 @@ int SimplePipelineHandler::start(Camera *camera, [[maybe_unused]] const ControlL\n \t\tStream *stream = &data->streams_[0];\n \t\tret = video->importBuffers(stream->configuration().bufferCount);\n \t}\n-\tif (ret < 0)\n+\tif (ret < 0) {\n+\t\treleasePipeline(data);\n \t\treturn ret;\n+\t}\n \n \tret = video->streamOn();\n \tif (ret < 0) {\n@@ -892,6 +928,8 @@ void SimplePipelineHandler::stop(Camera *camera)\n \n \tdata->converterBuffers_.clear();\n \tactiveCamera_ = nullptr;\n+\n+\treleasePipeline(data);\n }\n \n int SimplePipelineHandler::queueRequestDevice(Camera *camera, Request *request)\n@@ -1101,7 +1139,7 @@ bool SimplePipelineHandler::match(DeviceEnumerator *enumerator)\n \t\t\tbreak;\n \t\t}\n \n-\t\tentities_[entity] = { std::move(video), std::move(subdev) };\n+\t\tentities_[entity] = { std::move(video), std::move(subdev), {} };\n \t}\n \n \t/* Initialize each pipeline and register a corresponding camera. */\n@@ -1144,6 +1182,59 @@ V4L2Subdevice *SimplePipelineHandler::subdev(const MediaEntity *entity)\n \treturn iter->second.subdev.get();\n }\n \n+/**\n+ * \\brief Acquire all resources needed by the camera pipeline\n+ * \\return nullptr on success, a pointer to the contended pad on error\n+ */\n+const MediaPad *SimplePipelineHandler::acquirePipeline(SimpleCameraData *data)\n+{\n+\tfor (const SimpleCameraData::Entity &entity : data->entities_) {\n+\t\tconst EntityData &edata = entities_[entity.entity];\n+\n+\t\tif (entity.sink) {\n+\t\t\tauto iter = edata.owners.find(entity.sink);\n+\t\t\tif (iter != edata.owners.end() && iter->second != data)\n+\t\t\t\treturn entity.sink;\n+\t\t}\n+\n+\t\tif (entity.source) {\n+\t\t\tauto iter = edata.owners.find(entity.source);\n+\t\t\tif (iter != edata.owners.end() && iter->second != data)\n+\t\t\t\treturn entity.source;\n+\t\t}\n+\t}\n+\n+\tfor (const SimpleCameraData::Entity &entity : data->entities_) {\n+\t\tEntityData &edata = entities_[entity.entity];\n+\n+\t\tif (entity.sink)\n+\t\t\tedata.owners[entity.sink] = data;\n+\t\tif (entity.source)\n+\t\t\tedata.owners[entity.source] = data;\n+\t}\n+\n+\treturn nullptr;\n+}\n+\n+void SimplePipelineHandler::releasePipeline(SimpleCameraData *data)\n+{\n+\tfor (const SimpleCameraData::Entity &entity : data->entities_) {\n+\t\tEntityData &edata = entities_[entity.entity];\n+\n+\t\tif (entity.sink) {\n+\t\t\tauto iter = edata.owners.find(entity.sink);\n+\t\t\tASSERT(iter->second == data);\n+\t\t\tedata.owners.erase(iter);\n+\t\t}\n+\n+\t\tif (entity.source) {\n+\t\t\tauto iter = edata.owners.find(entity.source);\n+\t\t\tASSERT(iter->second == data);\n+\t\t\tedata.owners.erase(iter);\n+\t\t}\n+\t}\n+}\n+\n /* -----------------------------------------------------------------------------\n * Buffer Handling\n */\n", "prefixes": [ "libcamera-devel", "07/10" ] }