Re: [RFC PATCH 1/3] dt-bindings: fpga: Add support for user-key encrypted bitstream loading

[Conor Dooley <conor@kernel.org>]

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On Wed, Nov 22, 2023 at 11:14:02AM +0530, Nava kishore Manne wrote:
> Adds ‘encrypted-key-name’ property to support user-key encrypted
> bitstream loading use case.
> 
> Signed-off-by: Nava kishore Manne <nava.kishore.manne@amd.com>
> ---
>  .../devicetree/bindings/fpga/fpga-region.txt  | 32 +++++++++++++++++++

Is there a reason that this has not yet been converted to yaml?

>  1 file changed, 32 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/fpga/fpga-region.txt b/Documentation/devicetree/bindings/fpga/fpga-region.txt
> index 528df8a0e6d8..309334558b3f 100644
> --- a/Documentation/devicetree/bindings/fpga/fpga-region.txt
> +++ b/Documentation/devicetree/bindings/fpga/fpga-region.txt
> @@ -177,6 +177,9 @@ Optional properties:
>  	it indicates that the FPGA has already been programmed with this image.
>  	If this property is in an overlay targeting an FPGA region, it is a
>  	request to program the FPGA with that image.
> +- encrypted-key-name : should contain the name of an encrypted key file located
> +	on the firmware search path. It will be used to decrypt the FPGA image
> +	file with user-key.

I might be misreading things, but your driver code seems to assume that
this is an aes key. Nothing here seems to document that this is supposed
to be a key of a particular type.

Cheers,
Conor.

>  - fpga-bridges : should contain a list of phandles to FPGA Bridges that must be
>  	controlled during FPGA programming along with the parent FPGA bridge.
>  	This property is optional if the FPGA Manager handles the bridges.
> @@ -459,6 +462,35 @@ programming is the FPGA based bridge of fpga_region1.
>  	};
>  };
>  
> +Device Tree Example: Configure/Reconfigure Encrypted Image With User Key
> +========================================================================
> +
> +Users can encrypt FPGA configuration Images with their own key. While decrypting
> +the configuration Image the user needs to provide the same key.
> +"encrypted-key-name" Specifies the name of the FPGA image encrypted key file on
> +the firmware search path. The search path is described in the firmware class
> +documentation.
> +
> +/dts-v1/;
> +/plugin/;
> +
> +&fpga_region0 {
> +	#address-cells = <1>;
> +	#size-cells = <1>;
> +
> +	firmware-name = "soc_image2.rbf";
> +	encrypted-key-name = "key.nky";
> +
> +	gpio@10040 {
> +		compatible = "altr,pio-1.0";
> +		reg = <0x10040 0x20>;
> +		clocks = <0x2>;
> +		altr,ngpio = <0x4>;
> +		#gpio-cells = <0x2>;
> +		gpio-controller;
> +	};
> +};
> +
>  Constraints
>  ===========
>  
> -- 
> 2.25.1
> 

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