{"id":2353,"url":"https://patchwork.libcamera.org/api/patches/2353/?format=json","web_url":"https://patchwork.libcamera.org/patch/2353/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20191126233620.1695316-6-niklas.soderlund@ragnatech.se>","date":"2019-11-26T23:35:55","name":"[libcamera-devel,05/30] libcamera: buffer: Add Dmabuf to describe a dma buffer","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"196d3eb1fcff70f1047799132023209bb1e5b9b0","submitter":{"id":5,"url":"https://patchwork.libcamera.org/api/people/5/?format=json","name":"Niklas Söderlund","email":"niklas.soderlund@ragnatech.se"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/2353/mbox/","series":[{"id":579,"url":"https://patchwork.libcamera.org/api/series/579/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=579","date":"2019-11-26T23:35:50","name":"libcamera: Rework buffer API","version":1,"mbox":"https://patchwork.libcamera.org/series/579/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/2353/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/2353/checks/","tags":{},"headers":{"Return-Path":"","Received":["from bin-mail-out-05.binero.net (bin-mail-out-05.binero.net\n\t[195.74.38.228])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id D538761C59\n\tfor ;\n\tWed, 27 Nov 2019 00:39:28 +0100 (CET)","from bismarck.berto.se (p54ac5865.dip0.t-ipconnect.de\n\t[84.172.88.101]) by bin-vsp-out-02.atm.binero.net (Halon) with ESMTPA\n\tid fbea2f08-10a5-11ea-a0b9-005056917f90;\n\tWed, 27 Nov 2019 00:39:27 +0100 (CET)"],"X-Halon-ID":"fbea2f08-10a5-11ea-a0b9-005056917f90","Authorized-sender":"niklas@soderlund.pp.se","From":"=?utf-8?q?Niklas_S=C3=B6derlund?= ","To":"libcamera-devel@lists.libcamera.org","Date":"Wed, 27 Nov 2019 00:35:55 +0100","Message-Id":"<20191126233620.1695316-6-niklas.soderlund@ragnatech.se>","X-Mailer":"git-send-email 2.24.0","In-Reply-To":"<20191126233620.1695316-1-niklas.soderlund@ragnatech.se>","References":"<20191126233620.1695316-1-niklas.soderlund@ragnatech.se>","MIME-Version":"1.0","Content-Type":"text/plain; charset=UTF-8","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH 05/30] libcamera: buffer: Add Dmabuf to\n\tdescribe a dma buffer","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","X-List-Received-Date":"Tue, 26 Nov 2019 23:39:29 -0000"},"content":"A FrameBuffer object that holds a frame captured from a sensor consists\nof one or more plane(s). The memory of each plane can be accessed by\nusing a dma buffer. Add a class that describes a dmabuf to make it easy\nfor applications and IPAs to interact with memory.\n\nSigned-off-by: Niklas Söderlund \n---\n include/libcamera/buffer.h | 19 +++++++\n src/libcamera/buffer.cpp | 113 +++++++++++++++++++++++++++++++++++++\n 2 files changed, 132 insertions(+)","diff":"diff --git a/include/libcamera/buffer.h b/include/libcamera/buffer.h\nindex 33793b4ccf881eda..3c430afbfe8e9a05 100644\n--- a/include/libcamera/buffer.h\n+++ b/include/libcamera/buffer.h\n@@ -58,6 +58,25 @@ private:\n \tint fd_;\n };\n \n+class Dmabuf final\n+{\n+public:\n+\tDmabuf(int fd, unsigned int length);\n+\t~Dmabuf();\n+\n+\tint fd() const { return fd_.fd(); }\n+\tunsigned int length() const { return length_; }\n+\tvoid *mem();\n+\n+private:\n+\tint mmap();\n+\tint munmap();\n+\n+\tFileDescriptor fd_;\n+\tunsigned int length_;\n+\tvoid *mem_;\n+};\n+\n class Plane final\n {\n public:\ndiff --git a/src/libcamera/buffer.cpp b/src/libcamera/buffer.cpp\nindex 0676586ae3be2a61..5516055b2ea885c2 100644\n--- a/src/libcamera/buffer.cpp\n+++ b/src/libcamera/buffer.cpp\n@@ -177,6 +177,119 @@ FileDescriptor::~FileDescriptor()\n * an image may or may not be contiguous.\n */\n \n+/**\n+ * \\class Dmabuf\n+ * \\brief A memory region to store a single plane of a frame\n+ *\n+ * Planar pixel formats use multiple memory regions to store planes\n+ * corresponding to the different colour components of a frame. The Dmabuf class\n+ * tracks the specific details of a memory region used to store a single plane\n+ * for a given frame and provides the means to access the memory, both for the\n+ * application and for DMA. A Buffer then contains one or multiple planes\n+ * depending on its pixel format.\n+ *\n+ * To support DMA access, planes are associated with dmabuf objects represented\n+ * by file handles. Each plane carries a dmabuf file handle and an offset within\n+ * the buffer. Those file handles may refer to the same dmabuf object, depending\n+ * on whether the devices accessing the memory regions composing the image\n+ * support non-contiguous DMA to planes ore require DMA-contiguous memory.\n+ *\n+ * To support CPU access, planes carry the CPU address of their backing memory.\n+ * Similarly to the dmabuf file handles, the CPU addresses for planes composing\n+ * an image may or may not be contiguous.\n+ */\n+\n+/**\n+ * \\brief Set the dmabuf file handle backing the buffer\n+ * \\param[in] fd The dmabuf file handle\n+ * \\param[in] length The size of the memory region\n+ *\n+ * The \\a fd dmabuf file handle is duplicated and stored.\n+ */\n+Dmabuf::Dmabuf(int fd, unsigned int length)\n+\t: fd_(fd), length_(length), mem_(nullptr)\n+{\n+}\n+\n+Dmabuf::~Dmabuf()\n+{\n+\tmunmap();\n+}\n+\n+/**\n+ * \\fn Dmabuf::fd()\n+ * \\brief Get the dmabuf file handle backing the buffer\n+ */\n+\n+/**\n+ * \\fn Dmabuf::length()\n+ * \\brief Retrieve the length of the memory region\n+ * \\return The length of the memory region\n+ */\n+\n+/**\n+ * \\fn Dmabuf::mem()\n+ * \\brief Retrieve the CPU accessible memory address of the Dmabuf\n+ * \\return The CPU accessible memory address on success or nullptr otherwise.\n+ */\n+void *Dmabuf::mem()\n+{\n+\tif (!mem_)\n+\t\tmmap();\n+\n+\treturn mem_;\n+}\n+\n+/**\n+ * \\brief Map the plane memory data to a CPU accessible address\n+ *\n+ * \\return 0 on success or a negative error code otherwise\n+ */\n+int Dmabuf::mmap()\n+{\n+\tvoid *map;\n+\n+\tif (mem_)\n+\t\treturn 0;\n+\n+\tmap = ::mmap(NULL, length_, PROT_READ | PROT_WRITE, MAP_SHARED, fd_.fd(), 0);\n+\tif (map == MAP_FAILED) {\n+\t\tint ret = -errno;\n+\t\tLOG(Buffer, Error)\n+\t\t\t<< \"Failed to mmap plane: \" << strerror(-ret);\n+\t\treturn ret;\n+\t}\n+\n+\tmem_ = map;\n+\n+\treturn 0;\n+}\n+\n+/**\n+ * \\brief Unmap any existing CPU accessible mapping\n+ *\n+ * Unmap the memory mapped by an earlier call to mmap().\n+ *\n+ * \\return 0 on success or a negative error code otherwise\n+ */\n+int Dmabuf::munmap()\n+{\n+\tint ret = 0;\n+\n+\tif (mem_)\n+\t\tret = ::munmap(mem_, length_);\n+\n+\tif (ret) {\n+\t\tret = -errno;\n+\t\tLOG(Buffer, Warning)\n+\t\t\t<< \"Failed to unmap plane: \" << strerror(-ret);\n+\t} else {\n+\t\tmem_ = 0;\n+\t}\n+\n+\treturn ret;\n+}\n+\n Plane::Plane()\n \t: fd_(-1), length_(0), mem_(0)\n {\n","prefixes":["libcamera-devel","05/30"]}