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

[Michal Simek <michal.simek@amd.com>]

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:

   examples:
     - |
       #include <dt-bindings/gpio/gpio.h>
       remoteproc@0 {
         compatible = "xlnx,zynqmp-bram-rproc", "amd,bram-rproc";
         reg = <0x0 0x40000>;
         clocks = <&pl_clk>;
         firmware-name = "firmware.elf";
         reset-gpios = <&gpio0 0 GPIO_ACTIVE_LOW>;
       };

Thanks,
Michal