Re: [PATCH 3/9] dt-bindings: riscv: Add MIPS Boston board compatible

[Conor Dooley <conor@kernel.org>]

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On Wed, Oct 14, 2026 at 01:16:16PM +0000, Aleksa Paunovic wrote:
> Hi Conor,
> On 9/15/26 19:58, Conor Dooley wrote:
> > On Mon, Sep 14, 2026 at 03:55:51PM +0200, Aleksa Paunovic via B4 Relay wrote:
> >> From: Aleksa Paunovic <aleksa.paunovic@htecgroup.com>
> >>
> >> Document the MIPS Boston board compatible with a P8700 bitfile.
> >>
> >> Co-developed-by: Djordje Todorovic <djordje.todorovic@htecgroup.com>
> >> Signed-off-by: Djordje Todorovic <djordje.todorovic@htecgroup.com>
> >> Signed-off-by: Aleksa Paunovic <aleksa.paunovic@htecgroup.com>
> >> ---
> >>  Documentation/devicetree/bindings/riscv/gf.yaml | 27 +++++++++++++++++++++++++
> >>  1 file changed, 27 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/riscv/gf.yaml b/Documentation/devicetree/bindings/riscv/gf.yaml
> >> new file mode 100644
> >> index 0000000000000000000000000000000000000000..060910c9b04f482aee6f08f8f72232acbad118bb
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/riscv/gf.yaml
> >> @@ -0,0 +1,27 @@
> >> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >> +%YAML 1.2
> >> +---
> >> +$id: http://devicetree.org/schemas/riscv/gf.yaml#
> >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> +
> >> +title: GlobalFoundries MIPS SoC-based boards
> >> +
> >> +maintainers:
> >> +  - Djordje Todorovic <djordje.todorovic@htecgroup.com>
> >> +  - Aleksa Paunovic <aleksa.paunovic@htecgroup.com>
> >> +
> >> +description:
> >> +  GlobalFoundries MIPS SoC-based boards
> >> +
> >> +properties:
> >> +  $nodename:
> >> +    const: '/'
> >> +  compatible:
> >> +    oneOf:
> >> +      - description: Boston FPGA development board with a MIPS P8700 bitfile
> > I'm not convinced that this is specific enough at all.
> > I have absolutely no idea from this description if there's even a
> > specific FPGA involved here - this could mean a bitstream used on an Altera
> > platform or a Xilinx one, with totally different contents.
> I'll document this in v2. FWIW it's the identical board as [1], just with a 
> different bitstream. 
> > I'm only happy with FPGA bitstream content being supported if it is
> > versioned strictly and matches with some clear and obvious releases from
> > the vendor.
> I'll see if I can find one for v2. A version identifier would also work
> as a SoC-specific fallback, since it's the SoC that's bitstream content in our case.
> I'm not sure anything's public though. If not, I'd keep the board compatible 
> without a fallback (if possible). 

It's worth mentioning that this is the standard that we've discussed for
platforms on riscv, because of the nature of riscv and the ability of
anyone to create bitstreams for custom "SoCs" running on FPGAs.
It doesn't have to be public what a version actually means, but it must
be there.

Thanks,
Conor.

> >  I cannot even find this board by googling it, let alone find
> > clear information about what this could correspond to.
> >
> >> +        items:
> >> +          - const: gf,mips-p8700-boston
> > "items: - const" is the same as just having "const".
> Will fix in v2.
> >  SoC-specific
> > fallback is also missing, although in this case it'll be tricky to have
> > a meaningful one.
> 
> Links:
> [1] https://github.com/torvalds/linux/blob/master/arch/mips/boot/dts/img/boston.dts
> 
> Best regards,
> Aleksa

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