Date:   Wed, 15 Dec 2021 14:26:08 -0600
From:   Rob Herring <robh@kernel.org>
To:     David Brazdil <dbrazdil@google.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>, Will Deacon <will@kernel.org>,
        Andrew Scull <ascull@google.com>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/2] dt-bindings: firmware: Add Open Profile for DICE
Message-ID: <YbpPYG4rzPmJmwA6@robh.at.kernel.org>
References: <20211213195833.772892-1-dbrazdil@google.com>
 <20211213195833.772892-2-dbrazdil@google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20211213195833.772892-2-dbrazdil@google.com>
Precedence: bulk

On Mon, Dec 13, 2021 at 07:58:32PM +0000, David Brazdil wrote:
> Add DeviceTree bindings for Open Profile for DICE, an open protocol for
> measured boot. Firmware uses DICE to measure the hardware/software
> combination and generates Compound Device Identifier (CDI) certificates.
> These are stored in memory and the buffer is described in the DT as
> a reserved memory region referenced by a compatible device node.
> 
> Signed-off-by: David Brazdil <dbrazdil@google.com>
> ---
>  .../bindings/firmware/google,open-dice.yaml   | 51 +++++++++++++++++++
>  1 file changed, 51 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/firmware/google,open-dice.yaml
> 
> diff --git a/Documentation/devicetree/bindings/firmware/google,open-dice.yaml b/Documentation/devicetree/bindings/firmware/google,open-dice.yaml
> new file mode 100644
> index 000000000000..1aa69f381b8c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/firmware/google,open-dice.yaml
> @@ -0,0 +1,51 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/firmware/google,open-dice.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Open Profile for DICE Device Tree Bindings
> +
> +description: |
> +  This binding represents a reserved memory region containing data
> +  generated by the Open Profile for DICE protocol.
> +
> +  See https://pigweed.googlesource.com/open-dice/
> +
> +maintainers:
> +  - David Brazdil <dbrazdil@google.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - google,open-dice
> +
> +  memory-region:
> +    maxItems: 1
> +    description: |
> +      phandle to the reserved memory node to be associated with the device
> +      The reserved memory node should be defined as per the bindings,
> +      Documentation/devicetree/bindings/reserved-memory/reserved-memory.yaml
> +
> +required:
> +  - compatible
> +  - memory-region
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    reserved-memory {
> +        #address-cells = <2>;
> +        #size-cells = <1>;
> +
> +        dice_reserved: dice@12340000 {
> +            reg = <0x00 0x12340000 0x2000>;
> +            no-map;
> +        };
> +    };
> +
> +    dice {
> +        compatible = "google,open-dice";
> +        memory-region = <&dice_reserved>;

There's no need for this indirection. Just add the compatible to the 
dice@12340000 node. You can bind drivers to /reserved-memory nodes.

Rob