Re: [PATCH v2 1/2] dt-bindings: remoteproc: document AMD BRAM-based rproc

[Krzysztof Kozlowski <krzk@kernel.org>]

On 28/04/2026 15:09, Michal Simek wrote:
> 
> 
> On 4/28/26 11:14, Krzysztof Kozlowski wrote:
>> On 28/04/2026 11:04, Michal Simek wrote:
>>>
>>>
>>> On 4/28/26 10:47, Krzysztof Kozlowski wrote:
>>>> On 28/04/2026 10:33, Michal Simek wrote:
>>>>>
>>>>>
>>>>> On 4/28/26 08:50, Krzysztof Kozlowski wrote:
>>>>>> On Mon, Apr 27, 2026 at 09:27:02AM -0700, Ben Levinsky wrote:
>>>>>>> Describe an AMD BRAM-based soft-core processor subsystem instantiated in
>>>>>>> programmable logic and using dual-port BRAM for firmware storage and
>>>>>>> execution.
>>>>>>>
>>>>>>> The binding models a soft-core processor subsystem instantiated in AMD
>>>>>>> programmable logic and using dual-port BRAM for firmware storage and
>>>>>>> execution. The remoteproc device is represented as a child node whose
>>>>>>> reg property describes the firmware memory window in the processor-local
>>>>>>> address space. The parent bus node provides standard devicetree address
>>>>>>> translation through ranges so Linux can access the same BRAM through the
>>>>>>> system physical address space.
>>>>>>>
>>>>>>> A clock input feeds the soft-core processor subsystem, and an active-low
>>>>>>> reset GPIO holds the processor in reset until firmware loading
>>>>>>> completes. The firmware-name property is optional.
>>>>>>>
>>>>>>> Signed-off-by: Ben Levinsky <ben.levinsky@amd.com>
>>>>>>> ---
>>>>>>>     .../bindings/remoteproc/amd,bram-rproc.yaml   | 98 +++++++++++++++++++
>>>>>>>     1 file changed, 98 insertions(+)
>>>>>>>     create mode 100644 Documentation/devicetree/bindings/remoteproc/amd,bram-rproc.yaml
>>>>>>>
>>>>>>> diff --git a/Documentation/devicetree/bindings/remoteproc/amd,bram-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/amd,bram-rproc.yaml
>>>>>>> new file mode 100644
>>>>>>> index 000000000000..f16657dc0d9f
>>>>>>> --- /dev/null
>>>>>>> +++ b/Documentation/devicetree/bindings/remoteproc/amd,bram-rproc.yaml
>>>>>>> @@ -0,0 +1,98 @@
>>>>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>>>>> +%YAML 1.2
>>>>>>> +---
>>>>>>> +$id: http://devicetree.org/schemas/remoteproc/amd,bram-rproc.yaml#
>>>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>>>>> +
>>>>>>> +title: AMD BRAM-based Remote Processor
>>>>>>> +
>>>>>>> +maintainers:
>>>>>>> +  - Ben Levinsky <ben.levinsky@amd.com>
>>>>>>> +
>>>>>>> +description: |
>>>>>>> +  Soft-core processor subsystem instantiated in AMD programmable logic and
>>>>>>> +  using dual-port BRAM for firmware storage and execution.
>>>>>>
>>>>>> Isn't the soft-core or FPGA still part of some Xilinx SoC? Or is this
>>>>>> completely different thing from SoC and there is a design WITHOUT SoC
>>>>>> using this remote proc?
>>>>>
>>>>> In 99% case this is going to be used on Xilinx SOC with programmable logic next
>>>>> to ARM core.
>>>>> soft core means - means VHDL/Verilog code synthesized to programmable
>>>>> logic/fpga. It means exact location in chip varies based on build and constraints.
>>>>>
>>>>> hard core - physical HW location - like ARM cores in our chip.
>>>>>
>>>>> (ARM is providing RTL/code that even ARM cores in fpga emulated platforms are
>>>>> actually used as soft cores).
>>>>>
>>>>> Not sure if you want me to talk about that 1% use cases which are also possible
>>>>> but don't think anybody will design them.
>>>>
>>>> Then I would treat it exactly like every other block of a SoC - you need
>>>> a SoC specific compatible. If there is a fallback, SoC specific
>>>> compatible should be used in the fallback as well - that's all already
>>>> documented in writing-bindings.
>>>
>>> But which SOC? We have ZynqMP, Versal, Versal NET, Versal Gen 2. And all of
>>> these will use this configuration.
>>> Do you want to list all of them?
>>
>> "Then I would treat it exactly like every other block of a SoC"
> 
> No issue. Here is snippet.
> 
>    properties:
>      compatible:
>        items:
>          - enum:
>              - xlnx,zynqmp-bram-rproc
>              - xlnx,versal-bram-rproc
>              - xlnx,versal-net-bram-rproc
>              - amd,versal2-bram-rproc
>          - const: amd,bram-rproc
> 
>    The example should also be updated:

Yes, except what I wrote earlier and is mentioned in the writing
bindings doc - the specific compatible should be also the fallback.

Best regards,
Krzysztof