Hi,

On Thu, Jan 30, 2025 at 01:08:57PM +0000, Florent Tomasin wrote:

Introduce a CMA Heap dt-binding allowing custom CMA heap registrations.

• Note to the reviewers:

The patch was used for the development of the protected mode feature in Panthor CSF kernel driver and is not initially thought to land in the Linux kernel. It is mostly relevant if someone wants to reproduce the environment of testing. Please, raise interest if you think the patch has value in the Linux kernel.

Signed-off-by: Florent Tomasin florent.tomasin@arm.com

.../devicetree/bindings/dma/linux,cma.yml | 43 +++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 Documentation/devicetree/bindings/dma/linux,cma.yml

diff --git a/Documentation/devicetree/bindings/dma/linux,cma.yml b/Documentation/devicetree/bindings/dma/linux,cma.yml new file mode 100644 index 000000000000..c532e016bbe5 --- /dev/null +++ b/Documentation/devicetree/bindings/dma/linux,cma.yml @@ -0,0 +1,43 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/dma/linux-cma.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#

+title: Custom Linux CMA heap

+description:

• The custom Linux CMA heap device tree node allows registering
• of multiple CMA heaps.
• The CMA heap name will match the node name of the "memory-region".

+properties:

• compatible:
• enum:

•  - linux,cma
  

• memory-region:
• maxItems: 1
• description: |

•  Phandle to the reserved memory node associated with the CMA Heap.
  

•  The reserved memory node must follow this binding convention:
  

•   - Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
  

+examples:

• • |
• reserved-memory {

•  #address-cells = <2>;
  

•  #size-cells = <2>;
  

•  custom_cma_heap: custom-cma-heap {
  

•    compatible = "shared-dma-pool";
  

•    reg = <0x0 0x90600000 0x0 0x1000000>;
  

•    reusable;
  

•  };
  

• };
• device_cma_heap: device-cma-heap {

•  compatible = "linux,cma";
  

•  memory-region = <&custom_cma_heap>;
  

• };

Isn't it redundant with the linux,cma-default shared-dma-pool property already?

Maxime