From patchwork Tue Oct 2 14:27:28 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomasz Stanislawski X-Patchwork-Id: 1537551 Return-Path: X-Original-To: patchwork-dri-devel@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by patchwork1.kernel.org (Postfix) with ESMTP id 9ADE740135 for ; Tue, 2 Oct 2012 14:44:38 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 75609A0ABF for ; Tue, 2 Oct 2012 07:44:38 -0700 (PDT) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mailout2.samsung.com (mailout2.samsung.com [203.254.224.25]) by gabe.freedesktop.org (Postfix) with ESMTP id D1F369F39E for ; Tue, 2 Oct 2012 07:29:54 -0700 (PDT) Received: from epcpsbgm2.samsung.com (epcpsbgm2 [203.254.230.27]) by mailout2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0MB9000Y3S9UFW50@mailout2.samsung.com> for dri-devel@lists.freedesktop.org; Tue, 02 Oct 2012 23:29:54 +0900 (KST) X-AuditID: cbfee61b-b7f2b6d000000f14-65-506afa62366e Received: from epmmp2 ( [203.254.227.17]) by epcpsbgm2.samsung.com (EPCPMTA) with SMTP id E9.A1.03860.26AFA605; Tue, 02 Oct 2012 23:29:54 +0900 (KST) Received: from mcdsrvbld02.digital.local ([106.116.37.23]) by mmp2.samsung.com (Oracle Communications Messaging Server 7u4-24.01 (7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0MB9005A7S65K790@mmp2.samsung.com> for dri-devel@lists.freedesktop.org; Tue, 02 Oct 2012 23:29:54 +0900 (KST) From: Tomasz Stanislawski To: linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: [PATCHv9 17/25] Documentation: media: description of DMABUF exporting in V4L2 Date: Tue, 02 Oct 2012 16:27:28 +0200 Message-id: <1349188056-4886-18-git-send-email-t.stanislaws@samsung.com> X-Mailer: git-send-email 1.7.10 In-reply-to: <1349188056-4886-1-git-send-email-t.stanislaws@samsung.com> References: <1349188056-4886-1-git-send-email-t.stanislaws@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrCJMWRmVeSWpSXmKPExsVy+t9jQd2kX1kBBrd381lc+fqezYHR4373 caYAxigum5TUnMyy1CJ9uwSujI83fjIWzPWp2Nt7lbWBcYZdFyMnh4SAicS2yT3sELaYxIV7 69m6GLk4hASmM0qcmNMP5axjktjx8wwrSBUbUMexJZ8ZQWwRAQeJ03dnMYMUMQucZJZ4cv0V WEJYIEKie+cuMJtFQFVixfNlLCA2r4CHROOFbqh18hJP7/exgdicQPGfTy6A1QgJuEvsWd7E NoGRdwEjwypG0dSC5ILipPRcI73ixNzi0rx0veT83E2MYL8/k97BuKrB4hCjAAejEg/vrpOZ AUKsiWXFlbmHGCU4mJVEeK3vZwUI8aYkVlalFuXHF5XmpBYfYpTmYFES5232SAkQEkhPLEnN Tk0tSC2CyTJxcEo1MJYEXMnWiKkSPK3cy+ZZ99f2h8rx45sOKa19YSy7PFPtu4BZh9CRs9tS v4n1WV+VdLCPus6wdMWfSZqR39SC7MSUJq4RNdnQeSXH1uOJyod3lf1G4o8UXvkIm0+3y7n8 mHOZ0JxLqqLm/4qufw5XEJwyY2n+tAve65TPzfhVqGV97/N0Hb6ao0osxRmJhlrMRcWJAKn+ ypr3AQAA Cc: t.stanislaws@samsung.com, s.nawrocki@samsung.com, pawel@osciak.com, linux-doc@vger.kernel.org, mchehab@redhat.com, daniel.vetter@ffwll.ch, subashrp@gmail.com, linaro-mm-sig@lists.linaro.org, kyungmin.park@samsung.com, laurent.pinchart@ideasonboard.com, zhangfei.gao@gmail.com, airlied@redhat.com, remi@remlab.net, m.szyprowski@samsung.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dri-devel-bounces+patchwork-dri-devel=patchwork.kernel.org@lists.freedesktop.org Errors-To: dri-devel-bounces+patchwork-dri-devel=patchwork.kernel.org@lists.freedesktop.org This patch adds description and usage examples for exporting DMABUF file descriptor in V4L2. Signed-off-by: Tomasz Stanislawski Signed-off-by: Kyungmin Park CC: linux-doc@vger.kernel.org --- Documentation/DocBook/media/v4l/compat.xml | 3 + Documentation/DocBook/media/v4l/io.xml | 3 + Documentation/DocBook/media/v4l/v4l2.xml | 1 + Documentation/DocBook/media/v4l/vidioc-expbuf.xml | 212 +++++++++++++++++++++ 4 files changed, 219 insertions(+) create mode 100644 Documentation/DocBook/media/v4l/vidioc-expbuf.xml diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml index a46f95b..f0512aa 100644 --- a/Documentation/DocBook/media/v4l/compat.xml +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -2625,6 +2625,9 @@ ioctls. Importing DMABUF file descriptors as a new IO method described in . + + Exporting DMABUF files using &VIDIOC-EXPBUF; ioctl. + diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index 5b58657..476f448 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -488,6 +488,9 @@ DMA buffer from userspace using a file descriptor previously exported for a different or the same device (known as the importer role), or both. This section describes the DMABUF importer role API in V4L2. + Refer to DMABUF exporting for +details about exporting a V4L2 buffers as DMABUF file descriptors. + Input and output devices support the streaming I/O method when the V4L2_CAP_STREAMING flag in the capabilities field of &v4l2-capability; returned by diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index eee6908..d8c2597 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -543,6 +543,7 @@ and discussions on the V4L mailing list. &sub-enuminput; &sub-enumoutput; &sub-enumstd; + &sub-expbuf; &sub-g-audio; &sub-g-audioout; &sub-g-crop; diff --git a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml new file mode 100644 index 0000000..bf28e7d --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml @@ -0,0 +1,212 @@ + + + + ioctl VIDIOC_EXPBUF + &manvol; + + + + VIDIOC_EXPBUF + Export a buffer as a DMABUF file descriptor. + + + + + + int ioctl + int fd + int request + struct v4l2_exportbuffer *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_EXPBUF + + + + argp + + + + + + + + + Description + + + Experimental + This is an experimental + interface and may change in the future. + + +This ioctl is an extension to the memory +mapping I/O method therefore it is available only for +V4L2_MEMORY_MMAP buffers. It can be used to export a +buffer as a DMABUF file at any time after buffers have been allocated with the +&VIDIOC-REQBUFS; ioctl. + + To export a buffer, applicationis fill &v4l2-exportbuffer;. The + type field is set to the same buffer type as was +previously used with &v4l2-requestbuffers; type . +Applications must also set the index field. Valid +index numbers range from zero to the number of buffers allocated with +&VIDIOC-REQBUFS; (&v4l2-requestbuffers; count ) +minus one. For multi plane API, applications set the plane + field to the index of the plane to be exported. Valid planes +range from zero to the maximal number of valid planes for currently active +format. For single plane API, applications must set plane + to zero. Additional flags may be posted in the +flags field. Refer to a manual for open() for details. +Currently only O_CLOEXEC is supported. All other fields must be set to zero. +In a case of multi-planar API, every plane is exported separately using +multiple VIDIOC_EXPBUF calls. + + After calling VIDIOC_EXPBUF the fd + field will be set by a driver. This is a DMABUF file +descriptor. The application may pass it to other API. Refer to DMABUF importing for details about importing DMABUF +files into V4L2 nodes. A developer is encouraged to close a DMABUF file when it +is no longer used to avoid a resource leak. + + + +
+ Examples + + + Exporting a buffer. + +int buffer_export(int v4lfd, &v4l2-buf-type; bt, int index, int *dmafd) +{ + &v4l2-exportbuffer; expbuf; + + memset(&expbuf, 0, sizeof expbuf); + expbuf.type = bt; + expbuf.index = index; + if (ioctl(v4lfd, &VIDIOC-EXPBUF;, &expbuf) == -1) { + perror("VIDIOC_EXPBUF"); + return -1; + } + + *dmafd = expbuf.fd; + + return 0; +} + + + + + Exporting a buffer using multi plane API. + +int buffer_export_mp(int v4lfd, &v4l2-buf-type; bt, int index, + int dmafd[], int n_planes) +{ + int i; + + for (i = 0; i < n_planes; ++i) { + &v4l2-exportbuffer; expbuf; + + memset(&expbuf, 0, sizeof expbuf); + expbuf.type = bt; + expbuf.index = index; + expbuf.plane = i; + if (ioctl(v4lfd, &VIDIOC-EXPBUF;, &expbuf) == -1) { + perror("VIDIOC_EXPBUF"); + while (i) + close(dmafd[--i]); + return -1; + } + dmafd[i] = expbuf.fd; + } + + return 0; +} + + +
+ + + + + struct <structname>v4l2_exportbuffer</structname> + + &cs-str; + + + __s32 + fd + The DMABUF file descriptor associated with a buffer. Set by + a driver. + + + __u32 + flags + Flags for newly created file, currently only +O_CLOEXEC is supported, refer to the manual of open() for more +details. + + + __u32 + type + Type of the buffer, same as &v4l2-format; +type or &v4l2-requestbuffers; +type, set by the application. See + + + __u32 + index + Number of the buffer, set by the application. This field is +only used for memory mapping I/O and can range from +zero to the number of buffers allocated with the &VIDIOC-REQBUFS; ioctl +(&v4l2-requestbuffers; count) minus one. + + + __u32 + plane + Index of the plane to be exported when using multi plane +API. Otherwise this value must be set to zero. + + + __u32 + reserved[11] + Reserved field for future use. Must be set to zero. + + + +
+ + + + + &return-value; + + + EINVAL + + A queue is not in MMAP mode or DMABUF exporting is not +supported or flags or type + or index or plane + fields are invalid. + + + + + +