Re: [PATCH v1 1/5] Documentation: fpga: dfl: Add documentation for DFHv1

matthew.gerlach
2022-09-11T16:06:37Z

On Sun, 11 Sep 2022, Xu Yilun wrote:

> 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

I was hoping that the actual macro definitions would be sufficient, but I
will look into making a table.

Matthew Gerlach

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