xref: /freebsd/sys/contrib/device-tree/Bindings/iommu/apple,sart.yaml (revision fac71e4e09885bb2afa3d984a0c239a52e1a7418)

# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
%YAML 1.2
---
$id: http://devicetree.org/schemas/iommu/apple,sart.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Apple SART DMA address filter

maintainers:
  - Sven Peter <sven@svenpeter.dev>

description:
  Apple SART is a simple address filter for DMA transactions. Regions of
  physical memory must be added to the SART's allow list before any
  DMA can target these. Unlike a proper IOMMU no remapping can be done and
  special support in the consumer driver is required since not all DMA
  transactions of a single device are subject to SART filtering.

  SART1 has first been used since at least the A11 (iPhone 8 and iPhone X)
  and allows 36 bit of physical address space and filter entries with sizes
  up to 24 bit.

  SART2, first seen in A14 and M1, allows 36 bit of physical address space
  and filter entry size up to 36 bit.

  SART3, first seen in M1 Pro/Max, extends both the address space and filter
  entry size to 42 bit.

properties:
  compatible:
    oneOf:
      - items:
          - const: apple,t8112-sart
          - const: apple,t6000-sart
      - enum:
          - apple,t6000-sart
          - apple,t8103-sart

  reg:
    maxItems: 1

  power-domains:
    maxItems: 1

required:
  - compatible
  - reg

additionalProperties: false

examples:
  - |
    iommu@7bc50000 {
      compatible = "apple,t8103-sart";
      reg = <0x7bc50000 0x4000>;
    };