Re: [PATCH v3 13/17] ARM: Xen: Document UEFI support on Xen ARM virtual platforms

[Stefano Stabellini]

On Sat, 23 Jan 2016, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> 
> Add a "uefi" node under /hypervisor node in FDT, then Linux kernel could
> scan this to get the UEFI information.
> 
> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> ---
> CC: Rob Herring <robh@xxxxxxxxxx>
> ---
>  Documentation/devicetree/bindings/arm/xen.txt | 34 +++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/arm/xen.txt b/Documentation/devicetree/bindings/arm/xen.txt
> index 0f7b9c2..aa69405 100644
> --- a/Documentation/devicetree/bindings/arm/xen.txt
> +++ b/Documentation/devicetree/bindings/arm/xen.txt
> @@ -15,6 +15,26 @@ the following properties:
>  - interrupts: the interrupt used by Xen to inject event notifications.
>    A GIC node is also required.
>  
> +To support UEFI on Xen ARM virtual platforms, Xen populates the FDT "uefi" node
> +under /hypervisor with following parameters:
> +
> +________________________________________________________________________________
> +Name                      | Size   | Description
> +================================================================================
> +xen,uefi-system-table     | 64-bit | Guest physical address of the UEFI System
> +			  |	   | Table.
> +--------------------------------------------------------------------------------
> +xen,uefi-mmap-start       | 64-bit | Guest physical address of the UEFI memory
> +			  |	   | map.
> +--------------------------------------------------------------------------------
> +xen,uefi-mmap-size        | 32-bit | Size in bytes of the UEFI memory map
> +                          |        | pointed to in previous entry.
> +--------------------------------------------------------------------------------
> +xen,uefi-mmap-desc-size   | 32-bit | Size in bytes of each entry in the UEFI
> +                          |        | memory map.
> +--------------------------------------------------------------------------------
> +xen,uefi-mmap-desc-ver    | 32-bit | Version of the mmap descriptor format.
> +--------------------------------------------------------------------------------
>  
>  Example (assuming #address-cells = <2> and #size-cells = <2>):
>  
> @@ -22,4 +42,18 @@ hypervisor {
>  	compatible = "xen,xen-4.3", "xen,xen";
>  	reg = <0 0xb0000000 0 0x20000>;
>  	interrupts = <1 15 0xf08>;
> +	uefi {
> +		xen,uefi-system-table = <0xXXXXXXXX>;
> +		xen,uefi-mmap-start = <0xXXXXXXXX>;
> +		xen,uefi-mmap-size = <0xXXXXXXXX>;
> +		xen,uefi-mmap-desc-size = <0xXXXXXXXX>;
> +		xen,uefi-mmap-desc-ver = <0xXXXXXXXX>;
> +        };
>  };
> +
> +The format and meaning of these "xen,uefi-*" parameters are similar to those in
> +Documentation/arm/uefi.txt which are used by normal UEFI. But to distinguish
> +from normal UEFI, for Xen ARM virtual platforms it needs to introduce a Xen
> +specific UEFI which requires Xen hypervisor to provide hypercalls for Dom0 to
> +make use of the runtime services. Therefore, it defines these parameters under
> +/hypervisor node.

Please replace the paragraph with the following which mentions
include/xen/interface/platform.h and improves the wording:

"The format and meaning of the "xen,uefi-*" parameters are similar to
those in Documentation/arm/uefi.txt, which are provided by the regular
UEFI stub. However they differ because they are provided by the Xen
hypervisor, together with a set of UEFI runtime services implemented via
hypercalls, see include/xen/interface/platform.h."