[PATCH v4 3/3] doc: sophgo: milkv_duo: document Milk-V Duo board

[Kongyang Liu]

Heinrich Schuchardt <xypron.glpk at gmx.de> 于2024年1月28日周日 17:16写道：
>
> On 1/28/24 08:05, Kongyang Liu wrote:
> > Add document for Milk-V Duo board which based on Sophgo's CV1800B SoC.
> >
> > Signed-off-by: Kongyang Liu <seashell11234455 at gmail.com>
> >
> > ---
> >
> > (no changes since v3)
> >
> > Changes in v3:
> > - Add brief description of the procedure to run u-boot-dtb.bin
> >
> >   doc/board/index.rst            |  1 +
> >   doc/board/sophgo/index.rst     |  8 +++++
> >   doc/board/sophgo/milkv_duo.rst | 64 ++++++++++++++++++++++++++++++++++
> >   3 files changed, 73 insertions(+)
> >   create mode 100644 doc/board/sophgo/index.rst
> >   create mode 100644 doc/board/sophgo/milkv_duo.rst
> >
> > diff --git a/doc/board/index.rst b/doc/board/index.rst
> > index c96e5fda28..d0f9f355d2 100644
> > --- a/doc/board/index.rst
> > +++ b/doc/board/index.rst
> > @@ -46,6 +46,7 @@ Board-specific doc
> >      sifive/index
> >      sipeed/index
> >      socionext/index
> > +   sophgo/index
> >      st/index
> >      starfive/index
> >      ste/index
> > diff --git a/doc/board/sophgo/index.rst b/doc/board/sophgo/index.rst
> > new file mode 100644
> > index 0000000000..e097afdac6
> > --- /dev/null
> > +++ b/doc/board/sophgo/index.rst
> > @@ -0,0 +1,8 @@
> > +.. SPDX-License-Identifier: GPL-2.0+
> > +
> > +Sophgo
> > +======
> > +.. toctree::
> > +   :maxdepth: 1
> > +
> > +   milkv_duo
> > diff --git a/doc/board/sophgo/milkv_duo.rst b/doc/board/sophgo/milkv_duo.rst
> > new file mode 100644
> > index 0000000000..cb2ed1ad98
> > --- /dev/null
> > +++ b/doc/board/sophgo/milkv_duo.rst
> > @@ -0,0 +1,64 @@
> > +.. SPDX-License-Identifier: GPL-2.0+
> > +
> > +Milk-V Duo
> > +==========
> > +
> > +CV1800B RISC-V SoC
> > +------------------
> > +The CV1800B is a high-performance, low-power 1+1 64-bit RISC-V SoC from Sophgo.
> > +
> > +Mainline support
> > +----------------
> > +The support for following drivers are already enabled:
> > +1. ns16550 UART Driver.
> > +
> > +Building
> > +~~~~~~~~
> > +1. Add the RISC-V toolchain to your PATH.
> > +2. Setup ARCH & cross compilation environment variable:
> > +
> > +.. code-block:: console
> > +
> > +   export CROSS_COMPILE=<riscv64 toolchain prefix>
> > +   cd <U-Boot-dir>
> > +   make milkv_duo_defconfig
> > +   make
> > +
> > +This will generate u-boot-dtb.bin
> > +
> > +Booting
> > +~~~~~~~
> > +Currently, we rely on vendor FSBL(First Stage Boot Loader) to initialize the
> > +clock and load the u-boot image, then bootup from it.
> > +
> > +Alternatively, to run u-boot-dtb.bin on top of FSBL, follow these steps:
> > +
> > +1. Use the vendor-provided tool to create a unified fip.bin file containing
> > +   FSBL, OpenSBI, and U-Boot.
>
> Hello Kongyang,
>
> thank you for providing a documentation for the board.
>
> Concerning the usage of fip.bin it would be helpful to add more detail:
>
> * From where can the vendor code be downloaded?
> * Which are the commands to execute?
>

We have leveraged the BuildSDK from the Milk-V Duo project
(https://github.com/milkv-duo/duo-buildroot-sdk) and made slight modifications
to ensure compatibility with the mainline OpenSBI and U-Boot. After the
repository reaches a stable state, we will publish it on GitHub.

Best regards
Kongyang Liu

> Best regards
>
> Heinrich
>
> > +
> > +2. Place the generated fip.bin file into the FAT partition of the SD card.
> > +
> > +3. Insert the SD card into the board and power it on.
> > +
> > +The board will automatically execute the FSBL from the fip.bin file.
> > +Subsequently, it will transition to OpenSBI, and finally, OpenSBI will invoke
> > +U-Boot.
> > +
> > +
> > +Sample boot log from Milk-V Duo board
> > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > +.. code-block:: none
> > +
> > +   U-Boot 2024.01-rc5-00010-g51965baa36 (Dec 28 2023 - 13:15:53 +0800)milkv_duo
> > +
> > +   DRAM:  63.3 MiB
> > +   Core:  10 devices, 8 uclasses, devicetree: separate
> > +   Loading Environment from nowhere... OK
> > +   In:    serial at 4140000
> > +   Out:   serial at 4140000
> > +   Err:   serial at 4140000
> > +   Net:   No ethernet found.
> > +   milkv_duo# cpu detail
> > +     0: cpu at 0      rv64imafdc
> > +      ID = 0, freq = 0 Hz: L1 cache, MMU
> > +   milkv_duo#
>