On Wed, Jul 21, 2021 at 8:04 AM Maxime Ripard <maxime@xxxxxxxxxx> wrote: > > The Reserved Memory mechanism is supported by Linux thanks to its device > tree binding. > > Now that we have the DT validation in place, let's convert the device > tree bindings for that driver over to a YAML schema. Thanks for this! > > Cc: Mailing List <devicetree-spec@xxxxxxxxxxxxxxx> > Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx> > --- > .../reserved-memory/reserved-memory.txt | 141 --------------- > .../reserved-memory/reserved-memory.yaml | 167 ++++++++++++++++++ > 2 files changed, 167 insertions(+), 141 deletions(-) > delete mode 100644 Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt > create mode 100644 Documentation/devicetree/bindings/reserved-memory/reserved-memory.yaml > diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.yaml b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.yaml > new file mode 100644 > index 000000000000..b61527f11953 > --- /dev/null > +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.yaml > @@ -0,0 +1,167 @@ > +# SPDX-License-Identifier: GPL-2.0 I think this is okay to dual license. Grant (Linaro) is the original author and there's only a few lines from other authors. > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/reserved-memory/reserved-memory.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: /reserved-memory Node > + > +maintainers: > + - Devicetree Specification Mailing List <devicetree-spec@xxxxxxxxxxxxxxx> > + > +description: > > + Reserved memory is specified as a node under the /reserved-memory node. The > + operating system shall exclude reserved memory from normal usage one can > + create child nodes describing particular reserved (excluded from normal use) > + memory regions. Such memory regions are usually designed for the special > + usage by various device drivers. > + > +properties: > + $nodename: > + const: reserved-memory > + > + "#address-cells": true > + "#size-cells": true > + ranges: true > + > +patternProperties: > + "^(?!(ranges))[a-z,-]*(@[0-9]+)?$": Note that you could drop this and put under 'additionalProperties'. You would lose some node name checking, but there's really little standard on these nodes. > + type: object > + > + description: > > + Each child of the reserved-memory node specifies one or more regions of > + reserved memory. Each child node may either use a 'reg' property to > + specify a specific range of reserved memory, or a 'size' property with > + optional constraints to request a dynamically allocated block of memory. > + > + Following the generic-names recommended practice, node names should > + reflect the purpose of the node (ie. "framebuffer" or "dma-pool"). Unit > + address (@<address>) should be appended to the name if the node is a > + static allocation. > + > + properties: > + reg: true > + > + size: > + $ref: /schemas/types.yaml#/definitions/uint32-array > + description: > > + Length based on parent's \#size-cells. Size in bytes of memory to > + reserve. > + > + alignment: > + $ref: /schemas/types.yaml#/definitions/uint32-array > + description: > > + Length based on parent's \#size-cells. Address boundary for > + alignment of allocation. > + > + alloc-ranges: > + $ref: /schemas/types.yaml#/definitions/uint32-array > + description: > > + Address and Length pairs. Specifies regions of memory that are > + acceptable to allocate from. > + > + compatible: > + oneOf: > + - const: shared-dma-pool > + description: > > + This indicates a region of memory meant to be used as a shared > + pool of DMA buffers for a set of devices. It can be used by an > + operating system to instantiate the necessary pool management > + subsystem if necessary. > + > + # Vendor-specific compatibles in the form <vendor>,[<device>-]<usage> > + - const: mediatek,trustzone-bootinfo I think these should be separate schema files. At least, we're going to need to support separate files because I don't think we want ones adding custom properties here. This would fail unless we add every compatible here. We could also be a bit more exact as to which properties below apply (e.g. linux,.*-default is only valid for shared-dma-pool). > + > + no-map: > + type: boolean > + description: > > + Indicates the operating system must not create a virtual mapping of > + the region as part of its standard mapping of system memory, nor > + permit speculative access to it under any circumstances other than > + under the control of the device driver using the region. > + > + reusable: > + type: boolean > + description: > > + The operating system can use the memory in this region with the > + limitation that the device driver(s) owning the region need to be > + able to reclaim it back. Typically that means that the operating > + system can use that region to store volatile or cached data that > + can be otherwise regenerated or migrated elsewhere. > + > + linux,cma-default: > + type: boolean > + description: > > + If this property is present, then Linux will use the region for the > + default pool of the contiguous memory allocator. > + > + linux,dma-default: > + type: boolean > + description: > > + If this property is present, then Linux will use the region for the > + default pool of the consistent DMA allocator. > + > + allOf: > + - if: > + required: > + - no-map > + > + then: > + not: > + required: > + - reusable > + > + - if: > + required: > + - reusable > + > + then: > + not: > + required: > + - no-map > + > + oneOf: > + - required: > + - reg > + > + - required: > + - size > + > + additionalProperties: true > + > +additionalProperties: true This should be false, right? > + > +examples: > + - | > + / { > + #address-cells = <1>; > + #size-cells = <1>; > + model = "MediaTek MT2701 evaluation board"; > + compatible = "mediatek,mt2701-evb", "mediatek,mt2701"; > + > + reserved-memory { > + #address-cells = <1>; > + #size-cells = <1>; > + ranges; > + > + /* global autoconfigured region for contiguous allocations */ > + linux,cma { > + compatible = "shared-dma-pool"; > + reusable; > + size = <0x4000000>; > + alignment = <0x2000>; > + linux,cma-default; > + }; > + > + display_reserved: framebuffer@78000000 { > + reg = <0x78000000 0x800000>; > + }; > + > + trustzone-bootinfo@80002000 { > + compatible = "mediatek,trustzone-bootinfo"; > + reg = <0x80002000 0x1000>; > + }; > + }; > + }; > + > +... > -- > 2.31.1 >
