Re: [PATCH v2 2/2] board: sophgo: Add support for Milk-V Duo S

[Yao Zi <me@ziyao.cc>]

On Sat, Nov 07, 2026 at 02:52:13PM -0300, João Paulo Gonçalves wrote:
> Hi Yao Zi,
> 
> > Personally speaking, I prefer to turn on EFI related stuff
> > (BOOTMETH_EFI_BOOTMGR and EFI_PARTITION). Here EFI is more practical
> > since Duo-S carries 512MiB RAM, and I do have a device booted through
> > EFI.
> >
> 
> I will add the EFI configs on v3.
> 
> > > diff --git a/doc/board/sophgo/index.rst b/doc/board/sophgo/index.rst
> > > index 19c9a19b1d4b..61aceafceea3 100644
> > > --- a/doc/board/sophgo/index.rst
> > > +++ b/doc/board/sophgo/index.rst
> > > @@ -7,4 +7,5 @@ Sophgo
> > >  
> > >     milkv_duo
> > >     milkv_duo_256m
> > > +   milkv_duo_s
> > >     licheerv_nano
> > > diff --git a/doc/board/sophgo/milkv_duo_s.rst b/doc/board/sophgo/milkv_duo_s.rst
> > > new file mode 100644
> > > index 000000000000..9f6bf04d1842
> > > --- /dev/null
> > > +++ b/doc/board/sophgo/milkv_duo_s.rst
> > 
> > ...
> > 
> > > +Boot flow
> > > +~~~~~~~~~
> > > +The board boots from a FIP image, fip.bin, which contains the following
> > > +binaries:
> > > +
> > > +- FSBL (First Stage Boot Loader): the vendor bootloader [1]. It serves the
> > > +  same purpose as U-Boot SPL, but U-Boot does not support SPL for this SoC
> > > +  yet, so the vendor FSBL is required.
> > > +- Coprocessor firmware: the vendor firmware (cvirtos.bin) or custom firmware
> > > +  for the C906L coprocessor. It is not needed to boot U-Boot, but it is
> > > +  required by fiptool.
> > 
> > Please confirm whether this is correct. I remembered the coprocessor
> > firmware is optional, too.
> >
> 
> The coprocessor firmware is optional and is not needed to
> boot U-Boot. However, the fiptool from [1] always packs an RTOS image.
> If --rtos is not given, it falls back to a cvirtos.bin that does not
> exist at that path, so it fails:
> 
> $ ./fiptool \
>     --fsbl data/fsbl/cv181x.bin \
>     --ddr_param data/ddr_param.bin \
>     --opensbi fw_dynamic.bin \
>     --uboot u-boot.bin \
>     --text-base $((0x80200020))
> Packing Param1...
> Param1:    0x0
> FSBL:      0x1000
> Packing Param2...
> Traceback (most recent call last):
>   ...
>   File "fiptool/fiptool", line 84, in pack_param2
>     with open(args.rtos, 'rb') as f:
> FileNotFoundError: [Errno 2] No such file or directory: '.../fiptool/cvirtos.bin'
> 
> Passing an empty file does not help either, because the tool always sets
> the coprocessor load address in the FIP header, so the FSBL would still
> try to load and start it.
> 
> The FSBL repository has its own fiptool [2] that can generate fip.bin
> without the coprocessor firmware. When no coprocessor image is packed,
> the FSBL prints "No C906L image." and continues booting. This is also
> how meta-riscv [3] and the vendor Buildroot SDK [4] generate fip.bin,
> so it seems to be the more correct approach.
> 
> If you prefer, I can document this flow instead. In that case the
> documentation also needs to describe how to build the FSBL from source,
> since that fiptool is part of the FSBL build.

Yes, please do so. This sounds clearer.

> [1] https://github.com/sophgo/fiptool
> [2] https://github.com/sophgo/fsbl/blob/sg200x-dev/plat/cv181x/fiptool.py
> [3] https://github.com/riscv/meta-riscv/blob/master/recipes-bsp/milkv-duo-fsbl/milkv-duo-fsbl.bb
> [4] https://github.com/milkv-duo/duo-buildroot-sdk-v2
> 
> > Regards,
> > Yao Zi
> 
> Best Regards,
> João Paulo Gonçalves

-- 
Thanks,
Yao Zi

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