Dma buffer sharing framework. native JavaScript CEF extensions.

Dma buffer sharing framework Buffer Sharing and Synchronization ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. Different Approaches Video for Linux (V4L2) has a 'USERPTR' mechanism, which requires userspace mmap if the underlying memory is coming from some other device. is to provide a stable API on the changing Content API. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. clark@linaro. + +- Migration of backing storage if needed + After Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. 0_r0. Device drivers that support DMABUF can export a DMA buffer to userspace as a file descriptor (known as the exporter role), import a DMA buffer from userspace using a file descriptor previously exported for a different or the same device (known as the Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. • dma_buf_fd(): Returns a FD associated with the dma_buf object. txt blob: 3bbd5c51605a39e7726088b792c6ba46385e0152 [file] [log] [blame] DMA-BUFs A file descriptor connected to an abstract buffer, which can be easily passed and shared between userland, the kernel and devices. native JavaScript CEF extensions. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to Buffer Sharing and Synchronization The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library 3. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to 3. rst Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. semwal@xxxxxxxxxx> > > Signed-off-by: Sumit Semwal <sumit. org) Sumit Semwal (sumit. The three main components of this are: (1) dma-buf . txt Next message: Rob Clark: "Re: [Linaro-mm-sig] [RFC v2 1/2] dma-buf: Introduce dma buffersharing mechanism" Previous message: Francois Romieu: "Re: [PATCH 1/1] via-rhine: Split driver into . 1. DMA buffers This document describes the GStreamer caps negotiation of DMA buffers on Linux-like platforms. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to What is dma_buf API? A generic kernel level framework to share buffers. They are typically used to allocate buffers from a specific allocation pool, or to share buffers across frameworks. For example, the decoder may want its output to be directly shared with the display server for rendering without a copy. 12之前，通过打开 dev/ion 获取到 ion client，然后通过 IOC_ION_ALLOC ioctl 来分配一块新的buffer，到用户空间就是返回一个 ion handle，这个handle就代表了一块buffer。 为了把这块buffer分享给别的进程，通常需要调用 IOC_ION_SHARE ioctl来把buffer重新导出为dma-buf。 Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to In reply to: Sumit Semwal: " [PATCH 3/3] dma-buf: mark EXPERIMENTAL for 1st release. " In reply to: Sakari Ailus: "Re: [PATCH 2/3] dma-buf: Documentation for buffer sharing framework" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] On Sun, Jan 1, 2012 at 2:09 PM Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. The three main components of this are: (1) dma-buf This allows preferential + allocation, and/or migration of pages across different types of storage + available, if possible. / include / linux / dma-buf. support for ARM, Aura based window system and Ozone When finished, the buffer-user notifies end-of-dma to exporter + + Once the dma for the current buffer-user is over, it signals 'end-of-dma' to + the exporter using the dma_buf->ops->put_scatterlist () operation. - association of a file pointer with each user-buffer and associated The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to API • dma_buf_export(): Used to announce the wish to export a buffer Connects the exporter's private metadata for the buffer, an implementation of buffer operations for this buffer, and flags for the associated file. 6 days ago · Add documentation for dma buffer sharing framework, explaining the various operations, members and API of the dma buffer sharing framework. semwal Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. " In reply to: Sakari Ailus: "Re: [PATCH 2/3] dma-buf: Documentation for buffer sharing framework" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] On Sun, Jan 1, 2012 at 2:09 PM Allocating dma-buf using heaps ¶ Dma-buf Heaps are a way for userspace to allocate dma-buf objects. + + Interface: + void (*put_scatterlist) (struct dma_buf_attachment *, struct scatterlist *, + int nents); + + put_scatterlist This allows preferential + allocation, and/or migration of pages across different types of storage + available, if possible. Streaming I/O (DMA buffer importing) ¶ The DMABUF framework provides a generic method for sharing buffers between multiple devices. embedding browser window into third party applications. Signed-off-by: Sumit Semwal <sumit. > + > + Bracketing of dma access with {get,put}_scatterlist operations is essential > + to allow just-in-time backing of storage, and migration mid-way through a > + use-case. 4. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to Hi Randy, On Thu, Oct 13, 2011 at 4:00 AM, Randy Dunlap <rdunlap@xxxxxxxxxxxx> wrote: > On 10/11/2011 02:23 AM, Sumit Semwal wrote: > > Add documentation for dma buffer sharing framework, explaining the > > various operations, members and API of the dma buffer sharing > > framework. org> Signed-off-by: Sumit Semwal <sumit. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to Jan 11, 2012 · Of course, if the buffer lives in device memory or is otherwise constrained on the exporting side, it can be allocated sooner. The DMA buffer sharing is the efficient way to share the buffer/memory between different Linux kernel driver, such as codecs/3D/display/cameras. The three main components of this are: (1) dma-buf Buffer Sharing and Synchronization ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. A short note on dma_buf Share buffers across drivers Using anon file descriptor Allocator knows paddr Implements dma_buf_ops Export buffers as dmafd Application passes dmafd Buffer Sharing and Synchronization The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. Standardization: The DMA-BUF heaps framework offers a well-defined UAPI. + + Bracketing of dma access with {get,put}_scatterlist operations is essential + to allow just-in-time backing of storage, and migration mid-way through a + use-case. + +- Migration of backing storage if needed + If after Buffer Sharing and Synchronization ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. rst - kernel/common - Git at Googledma-buf. + +- Migration of backing storage if needed + If after Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. > + > +- Migration of backing storage if Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. com / rob. h files. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to When finished, the buffer-user notifies end-of-DMA to exporter > + > + Once the DMA for the current buffer-user is over, it signals 'end-of-DMA' to > + the exporter using the dma_buf_unmap_attachment API. The three main components of this are: (1) dma-buf Documentation on DMA buffer sharing in the Android kernel for MSM platform. Any device driver which Pushed to staging ~2013 Generic buffer sharing for multiple device pipelines Trying to replace per SoC/gpu custom buffer sharing implementations Motivated the development of DMA-BUFs upstream & became an early user Pseudo-constraint solving interface Bitfield of heap types you’d accept, and ION will allocate from one of those Buffer Sharing and Synchronization The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. Heaps ¶ A heap represents a specific allocator. The three main components of this are: (1) dma-buf android / kernel / msm / android-5. SPICE) Mar 27, 2025 · This wasn't possible with ION because allocation from any heap only required access to the /dev/ion device. Returns a handle to the dma_buf object with all the above associated information. com> Buffer Sharing and Synchronization The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. The idea is to share memory betwen the different processors in an SoC. Page generated on 2017-04-01 14:43 EST. I could also achieve this via shared memory linux framework instead of the dma buffer framework in the linux Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. h - kernel/common - Git at Googlefile log blame edit Add documentation for dma buffer sharing framework, explaining the various operations, members and API of the dma buffer sharing framework. + + - Then, the buffer-user returns the buffer reference to exporter. The three main components of this are: (1) dma-buf Buffer Sharing and Synchronization The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. + + Bracketing of DMA access with {map,unmap}_dma_buf operations is essential + to allow just-in-time backing of storage, and migration mid-way through a + use-case. Dec 26, 2011 · Introduce DMA buffer sharing mechanism Hello Everyone, Post some discussion as an RFC, here is the patch for introducing DMA buffer sharing mechanism - change history is in the changelog below. semwal@ti. ABI stability: Unlike ION, the DMA-BUF heaps framework's IOCTL interface is ABI stable because it's maintained in the upstream Linux kernel. Documentation/driver-api/dma-buf. The framework allows: - different devices to 'attach' themselves to this buffer, to facilitate backing storage negotiation, using dma_buf_attach () API. The three main components of this are: (1) dma-buf DMA Buffer Sharing API Guide ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Sumit Semwal <sumit dot semwal at linaro dot org> <sumit dot semwal at ti dot com> This document serves as a guide to device-driver writers on what is the dma-buf buffer sharing API, how to use it for exporting and using shared buffers. Defines a new buffer object, which provides mechanism for exporting and using shared buffers. > + > + Interface: > + void dma_buf_unmap_attachment (struct dma_buf_attachment *, > + struct sg_table *); > + > + This is a wrapper to dma Documentation/dma-buf-sharing. Any device driver which wishes to be a part of DMA buffer sharing, can do so as either the 'exporter Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. The three main components of this are: (1) dma-buf Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. Sumit Semwal Add documentation for dma buffer sharing framework, explaining the various operations, members and API of the dma buffer sharing Feb 17, 2021 · 此后 dma-buf 被广泛应用于内核多媒体驱动开发中，尤其在 V4L2、DRM 子系统中得到了充分应用。 LWN: DMA buffer sharing in 3. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to Next message: Rob Clark: "Re: [Linaro-mm-sig] [RFC v2 1/2] dma-buf: Introduce dma buffersharing mechanism" Previous message: Francois Romieu: "Re: [PATCH 1/1] via-rhine: Split driver into . DMA Buffer Sharing Framework: An IntroductionDMA Buffer Sharing Framework: An Introduction Embedded Linux Conference, SFO, 2012 Rob Clark ([email protected] / [email protected]) Sumit Semwal ([email protected] / [email protected]) Agenda • Why DMA Buffer Sharing? • What is dma_buf buffer sharing API? • dma_buf operations • Buffer Exporter • Buffer Importer • API • Example of Apr 1, 2017 · Linux Kernel DocumentationBased on kernel version 4. CEF supports only X86 builds with GTK/X11 backends. Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. This allows preferential + allocation, and/or migration of pages across different types of storage + available, if possible. This allows preferential > + allocation, and/or migration of pages across different types of storage > + available, if possible. g. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to Feb 16, 2021 · 在kernel 4. The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. Provides uniform APIs that allow various operations related to buffer sharing. h blob: 1f78d1594cc7a2400bf7f383439c88dcdd1e53c5 [file] [log] [blame] Oct 11, 2011 · + void dma_buf_detach(struct dma_buf *dmabuf, + struct dma_buf_attachment *dmabuf_attach); + + This API removes the attachment from the list in dmabuf, and optionally calls + dma_buf->ops->detach(), if provided by exporter, for any housekeeping bits. 8. com / sumit. c and . The three main components of this are: (1) dma-buf DMA Buffer Sharing Framework: An Introduction Embedded Linux Conference, SFO, 2012 Rob Clark (rob@ti. After the DMA operation is completed, the sharing driver should unmap the buffer with: void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, struct sg_table *sg_table); android / kernel / common / a7827a2a60218b25f222b54f77ed38f57aebe08b / . Streaming I/O (DMA buffer importing) The DMABUF framework provides a generic method for sharing buffers between multiple devices. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to We would like to show you a description here but the site won’t allow us. / Documentation / dma-buf-sharing. The three main components of this are: (1) dma-buf Jun 16, 2023 · Thank you. 4 days ago · A new buffer object dma_buf is added, with operations and API to allow easy sharing of this buffer object across devices. Buffer Sharing and Synchronization The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. Feb 8, 2012 · Besides being a memory pool manager, ION also enables its clients to share buffers, hence it treads the same ground as the DMA buffer sharing framework from Linaro (DMABUF). This is used, for example, by drm "prime" multi-GPU support, but is of course not limited to GPU use cases. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to Oct 3, 2025 · Buffer Sharing and Synchronization (dma-buf) ============================================ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. txt - platform/hardware/bsp/kernel/raspberrypi/pi-v4. 4 - Git at Googledma-buf-sharing. + +- Migration of backing storage if needed + After Design Philosophy - Generic Based on dma-buf subsystem which Generic way provided by kernel to share DMA buffers Already been supported by many device drivers Supported by Linux graphics stacks Used by remote protocol (e. Various subsystems - V4L2, GPU-accessors, DRI to name a few - have felt the need to have a common mechanism to share memory buffers across different The document explains DMA-BUF sharing in MSM kernel, detailing its mechanisms and usage for efficient buffer sharing across different subsystems. > + > +- Migration of backing storage if include/linux/dma-buf. semwal@linaro. One processor runs linux and I would like to develop a kernel driver which would allocate memory from dma buffer and then share this addres to the remote processor over the rpmsg IPC. > > > > Signed-off-by: Sumit Semwal <sumit. > + > + Interface: > + void dma_buf_unmap_attachment (struct dma_buf_attachment *, > + struct sg_table *); > + > + This is a wrapper to dma Linux ARM, OMAP, Xscale Kernel: Re: [PATCH 2/3] dma-buf: Documentation for buffer sharing framework The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. 6 / . 3 Patch: dma-buf: Documentation for buffer sharing framework Patch: dma-buf: Introduce dma buffer sharing mechanism 第一个使用 dma-buf 的 DRM 分支: drm-prime-dmabuf 概念 Embedded Framework wrapping the chromium into a library libcef. org) f Agenda • Why DMA Buffer Sharing? • What is dma_buf buffer sharing API? • dma_buf operations • Buffer Exporter • Buffer Importer • API • Example of sharing • Importance of buffer operations Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to Why DMA buffer sharing? A uniform mechanism to share DMA buffers across different devices and sub-systems does not exist. The Linux kernel currently supports the following heaps: Hi Sumit and Arnd, On Mon, Dec 26, 2011 at 02:53:16PM +0530, Sumit Semwal wrote: > Add documentation for dma buffer sharing framework, explaining the > various When finished, the buffer-user notifies end-of-DMA to exporter > + > + Once the DMA for the current buffer-user is over, it signals 'end-of-DMA' to > + the exporter using the dma_buf_unmap_attachment API. This is used, for example, by drm “prime” multi-GPU support, but is of course not limited to GPU use cases. As an example, it is used extensively by the DRM subsystem to exchange buffers between processes, contexts, library APIs within the same process, and also to Buffer Sharing and Synchronization ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. 1 DMA Buffer Sharing API Guide 2 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3 4 Sumit Semwal 5 <sumit dot semwal at linaro dot org> 6 <sumit dot semwal at ti dot com> 7 8 This document serves as a guide to device-driver writers on what is the dma-buf 9 buffer sharing API, how to use it for exporting and using Buffer Sharing and Synchronization (dma-buf) ¶ The dma-buf subsystem provides the framework for sharing buffers for hardware (DMA) access across multiple device drivers and subsystems, and for synchronizing asynchronous hardware access. 10. " Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Add documentation for dma buffer sharing framework, explaining the various operations, members and API of the dma buffer sharing This allows preferential > + allocation, and/or migration of pages across different types of storage > + available, if possible. ziqz eydptd rlmux arjnm oyhe ott mlpd jcysn tbglh zvkush lap god oaoiksl frg ywic