by Rob Herring (Arm)

[permalink] [raw]

Subject: Re: [PATCH v2 2/8] dt-bindings: sram: Convert SRAM bindings to json-schema

On Wed, Sep 18, 2019 at 07:31:35PM +0200, Krzysztof Kozlowski wrote:
> Convert generic mmio-sram bindings to DT schema format using
> json-schema.

I've been slow getting to this because I started on the same thing...

>
> Signed-off-by: Krzysztof Kozlowski <[email protected]>
>
> ---
>
> Changes since v1:
> 1. Indent example with four spaces (more readable).
> ---
> .../devicetree/bindings/sram/sram.txt | 80 ----------
> .../devicetree/bindings/sram/sram.yaml | 138 ++++++++++++++++++
> 2 files changed, 138 insertions(+), 80 deletions(-)
> delete mode 100644 Documentation/devicetree/bindings/sram/sram.txt
> create mode 100644 Documentation/devicetree/bindings/sram/sram.yaml

> diff --git a/Documentation/devicetree/bindings/sram/sram.yaml b/Documentation/devicetree/bindings/sram/sram.yaml
> new file mode 100644
> index 000000000000..8d9d6ce494b2
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sram/sram.yaml
> @@ -0,0 +1,138 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/sram/sram.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Generic on-chip SRAM
> +
> +maintainers:
> + - FIXME <[email protected]>

You can put me.

> +
> +description: |+
> + Simple IO memory regions to be managed by the genalloc API.
> +
> + Each child of the sram node specifies a region of reserved memory. Each
> + child node should use a 'reg' property to specify a specific range of
> + reserved memory.
> +
> + Following the generic-names recommended practice, node names should
> + reflect the purpose of the node. Unit address (@<address>) should be
> + appended to the name.
> +
> +properties:
> + $nodename:
> + pattern: "^sram(@.*)?"
> +
> + compatible:
> + items:
> + - enum:
> + - mmio-sram
> + - atmel,sama5d2-securam

I was trying to go down the path of putting all the compatibles for
various SRAM bindings here, but I ran into some issues. I need to
revisit as I've forgotten the exact issue.

This would need to be a 'contains' if this is going to work for others.

> +
> + reg:
> + maxItems: 1
> +
> + "#address-cells":
> + description: Should use the same values as the root node.
> +
> + "#size-cells":
> + description: Should use the same values as the root node.

I defined both of these to be 1 as 4GB of SRAM should be enough for a
while. We can debate 1 or 2 cells vs. 1, but there's no reason it has to
be the same as the root (unless we're failing to do address
translation).

> +
> + ranges:
> + description:
> + Should translate from local addresses within the sram to bus addresses.
> +
> + no-memory-wc:
> + description:
> + The flag indicating, that SRAM memory region has not to be remapped
> + as write combining. WC is used by default.
> + type: boolean
> +
> + # TODO: additionalProperties: false
> +
> +patternProperties:
> + "^([a-z]*-)?sram@[a-f0-9]$":
> + type: object
> + description:
> + Each child of the sram node specifies a region of reserved memory.
> + properties:
> + reg:
> + description:
> + IO mem address range, relative to the SRAM range.

maxItems: 1

> +
> + compatible:
> + $ref: /schemas/types.yaml#/definitions/string
> + description:
> + Should contain a vendor specific string in the form
> + <vendor>,[<device>-]<usage>
> +
> + pool:
> + description:
> + Indicates that the particular reserved SRAM area is addressable
> + and in use by another device or devices.
> + type: boolean
> +
> + export:
> + description:
> + Indicates that the reserved SRAM area may be accessed outside
> + of the kernel, e.g. by bootloader or userspace.
> + type: boolean
> +
> + protect-exec:
> + description: |
> + Same as 'pool' above but with the additional constraint that code
> + will be run from the region and that the memory is maintained as
> + read-only, executable during code execution. NOTE: This region must
> + be page aligned on start and end in order to properly allow
> + manipulation of the page attributes.
> + type: boolean
> +
> + label:
> + $ref: /schemas/types.yaml#/definitions/string

Already has a type definition.

> + description:
> + The name for the reserved partition, if omitted, the label is taken
> + from the node name excluding the unit address.
> +
> + clocks:
> + description:
> + A list of phandle and clock specifier pair that controls the
> + single SRAM clock.
> +
> + # TODO: additionalProperties: false
> +
> + required:
> + - reg
> +
> +required:
> + - compatible
> + - reg
> + - "#address-cells"
> + - "#size-cells"
> + - ranges
> +
> +examples:
> + - |
> + sram: sram@5c000000 {
> + compatible = "mmio-sram";
> + reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */
> +
> + #address-cells = <1>;
> + #size-cells = <1>;
> + ranges = <0 0x5c000000 0x40000>;
> +
> + smp-sram@100 {
> + compatible = "socvendor,smp-sram";
> + reg = <0x100 0x50>;
> + };
> +
> + device-sram@1000 {
> + reg = <0x1000 0x1000>;
> + pool;
> + };
> +
> + exported@20000 {
> + reg = <0x20000 0x20000>;
> + export;
> + };
> + };
> --
> 2.17.1
>