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Date:   Sun, 11 Sep 2022 17:57:15 +0800
From:   Xu Yilun <yilun.xu@intel.com>
To:     matthew.gerlach@linux.intel.com
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        basheer.ahmed.muddebihal@intel.com, trix@redhat.com,
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Subject: Re: [PATCH v1 1/5] Documentation: fpga: dfl: Add documentation for
 DFHv1
Message-ID: <Yx2w+yl9SFFx0Qtx@yilunxu-OptiPlex-7050>
References: <20220906190426.3139760-1-matthew.gerlach@linux.intel.com>
 <20220906190426.3139760-2-matthew.gerlach@linux.intel.com>
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On 2022-09-06 at 12:04:22 -0700, matthew.gerlach@linux.intel.com wrote:
> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> 
> Add documentation describing the extentions provided by Version
> 1 of the Device Feature Header (DFHv1).
> 
> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> ---
>  Documentation/fpga/dfl.rst | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst
> index 15b670926084..31699b89781e 100644
> --- a/Documentation/fpga/dfl.rst
> +++ b/Documentation/fpga/dfl.rst
> @@ -561,6 +561,30 @@ new DFL feature via UIO direct access, its feature id should be added to the
>  driver's id_table.
>  
>  
> +Extending the Device Feature Header - DFHv1
> +===========================================
> +The current 8 bytes of the Device Feature Header, hereafter referred to as
> +to DFHv0, provide very little opportunity for the hardware to describe itself
> +to software. Version 1 of the Device Feature Header (DFHv1) is being introduced
> +to provide increased flexibility and extensibility to hardware designs using
> +Device Feature Lists.  The list below describes some of the goals behind the
> +changes in DFHv1:
> +
> +* Provide a standardized mechanism for features to describe
> +  parameters/capabilities to software.
> +* Standardize the use of a GUID for all DFHv1 types.
> +* Decouple the location of the DFH from the register space of the feature itself.
> +
> +Modeled after PCI Capabilities, DFHv1 Parameters provide a mechanism to associate
> +a list of parameter values to a particular feature.
> +
> +With DFHv0, not all features types contained a GUID.  DFHv1 makes the GUILD standard
> +across all types.
> +
> +With DFHv0, the register map of a given feature is located immediately following
> +the DFHv0 in the memory space.  With DFHv1, the location of the feature register
> +map can be specified as an offset to the DFHv1 or as an absolute address.

Could you make a table or diagram to describe the data structure layout of DFHv1
extention.

Thanks,
Yilun

> +
>  Open discussion
>  ===============
>  FME driver exports one ioctl (DFL_FPGA_FME_PORT_PR) for partial reconfiguration
> -- 
> 2.25.1
>