diff options
| -rw-r--r-- | Documentation/userspace-api/dma-buf-heaps.rst | 25 | ||||
| -rw-r--r-- | Documentation/userspace-api/index.rst | 1 | ||||
| -rw-r--r-- | MAINTAINERS | 1 |
3 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/userspace-api/dma-buf-heaps.rst b/Documentation/userspace-api/dma-buf-heaps.rst new file mode 100644 index 000000000000..535f49047ce6 --- /dev/null +++ b/Documentation/userspace-api/dma-buf-heaps.rst @@ -0,0 +1,25 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================== +Allocating dma-buf using heaps +============================== + +Dma-buf Heaps are a way for userspace to allocate dma-buf objects. They are +typically used to allocate buffers from a specific allocation pool, or to share +buffers across frameworks. + +Heaps +===== + +A heap represents a specific allocator. The Linux kernel currently supports the +following heaps: + + - The ``system`` heap allocates virtually contiguous, cacheable, buffers. + + - The ``cma`` heap allocates physically contiguous, cacheable, + buffers. Only present if a CMA region is present. Such a region is + usually created either through the kernel commandline through the + `cma` parameter, a memory region Device-Tree node with the + `linux,cma-default` property set, or through the `CMA_SIZE_MBYTES` or + `CMA_SIZE_PERCENTAGE` Kconfig options. Depending on the platform, it + might be called ``reserved``, ``linux,cma``, or ``default-pool``. diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst index b1395d94b3fd..9cbe4390c872 100644 --- a/Documentation/userspace-api/index.rst +++ b/Documentation/userspace-api/index.rst @@ -44,6 +44,7 @@ Devices and I/O :maxdepth: 1 accelerators/ocxl + dma-buf-heaps dma-buf-alloc-exchange gpio/index iommufd diff --git a/MAINTAINERS b/MAINTAINERS index d28115625fd3..edcd0d7ca3be 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6913,6 +6913,7 @@ L: dri-devel@lists.freedesktop.org L: linaro-mm-sig@lists.linaro.org (moderated for non-subscribers) S: Maintained T: git https://gitlab.freedesktop.org/drm/misc/kernel.git +F: Documentation/userspace-api/dma-buf-heaps.rst F: drivers/dma-buf/dma-heap.c F: drivers/dma-buf/heaps/* F: include/linux/dma-heap.h |