Apple SoCs such as the M1 come with a simple DMA address filter called SART. Unlike a real IOMMU no pagetables can be configured but instead DMA transactions can be allowed for up to 16 paddr regions. Signed-off-by: Sven Peter <sven@xxxxxxxxxxxxx> --- .../bindings/soc/apple/apple,sart.yaml | 52 +++++++++++++++++++ MAINTAINERS | 1 + 2 files changed, 53 insertions(+) create mode 100644 Documentation/devicetree/bindings/soc/apple/apple,sart.yaml diff --git a/Documentation/devicetree/bindings/soc/apple/apple,sart.yaml b/Documentation/devicetree/bindings/soc/apple/apple,sart.yaml new file mode 100644 index 000000000000..d8177b3a3fba --- /dev/null +++ b/Documentation/devicetree/bindings/soc/apple/apple,sart.yaml @@ -0,0 +1,52 @@ +# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/soc/apple/apple,sart.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Apple SART DMA address filter + +maintainers: + - Sven Peter <sven@xxxxxxxxxxxxx> + +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: + enum: + - apple,t6000-sart + - apple,t8103-sart + + reg: + maxItems: 1 + + power-domains: + maxItems: 1 + +required: + - compatible + - reg + +additionalProperties: false + +examples: + - | + sart@7bc50000 { + compatible = "apple,t8103-sart"; + reg = <0x7bc50000 0x4000>; + }; diff --git a/MAINTAINERS b/MAINTAINERS index cd0f68d4a34a..027c3b4ad61c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1774,6 +1774,7 @@ F: Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml F: Documentation/devicetree/bindings/pci/apple,pcie.yaml F: Documentation/devicetree/bindings/pinctrl/apple,pinctrl.yaml F: Documentation/devicetree/bindings/power/apple* +F: Documentation/devicetree/bindings/soc/apple/* F: Documentation/devicetree/bindings/watchdog/apple,wdt.yaml F: arch/arm64/boot/dts/apple/ F: drivers/i2c/busses/i2c-pasemi-core.c -- 2.25.1
