Hi,
On Fri, May 01, 2020 at 07:39:46AM +0000, John Stultz wrote:
This patch adds a linux,cma-heap property for CMA reserved memory regions, which will be used to allow the region to be exposed via the DMA-BUF Heaps interface
Cc: Rob Herring robh+dt@kernel.org Cc: Sumit Semwal sumit.semwal@linaro.org Cc: "Andrew F. Davis" afd@ti.com Cc: Benjamin Gaignard benjamin.gaignard@linaro.org Cc: Liam Mark lmark@codeaurora.org Cc: Pratik Patel pratikp@codeaurora.org Cc: Laura Abbott labbott@redhat.com Cc: Brian Starkey Brian.Starkey@arm.com Cc: Chenbo Feng fengc@google.com Cc: Alistair Strachan astrachan@google.com Cc: Sandeep Patil sspatil@google.com Cc: Hridya Valsaraju hridya@google.com Cc: Christoph Hellwig hch@lst.de Cc: Marek Szyprowski m.szyprowski@samsung.com Cc: Robin Murphy robin.murphy@arm.com Cc: Andrew Morton akpm@linux-foundation.org Cc: devicetree@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linux-mm@kvack.org Signed-off-by: John Stultz john.stultz@linaro.org
.../devicetree/bindings/reserved-memory/reserved-memory.txt | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt index bac4afa3b197..e97b6a4c3bc0 100644 --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt @@ -68,6 +68,9 @@ Linux implementation note:
- If a "linux,cma-default" property is present, then Linux will use the region for the default pool of the contiguous memory allocator.
+- If a "linux,cma-heap" property is present, then Linux will expose the
- the CMA region via the DMA-BUF Heaps interface.
Would it be useful or even possible to give some indication of what the heap will end up being called? I'm afraid I don't remember what if any conclusions came out of previous discussions on UAPI for heap enumeration.
I suppose CMA names haven't been relevant to userspace before, but they perhaps would be with this change.
Alternatively, leaving it effectively undefined doesn't tie us down, and something like links in sysfs can be added as a richer API in the future.
Cheers, -Brian
- If a "linux,dma-default" property is present, then Linux will use the region for the default pool of the consistent DMA allocator.
-- 2.17.1