Re: [RFC PATCH V4 6/6] riscv: soc: Add Allwinner SoC kconfig option

[Randy Dunlap]

On 9/13/21 7:34 PM, Guo Ren wrote:
> On Tue, Sep 14, 2021 at 2:49 AM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
> > On 9/13/21 2:20 AM, Guo Ren wrote:
> > > On Mon, Sep 13, 2021 at 4:45 PM Maxime Ripard <maxime@xxxxxxxxxx> wrote:
> > > > Hi,
> > > >
> > > > On Sat, Sep 11, 2021 at 05:21:39PM +0800, guoren@xxxxxxxxxx wrote:
> > > > > From: Liu Shaohua <liush@xxxxxxxxxxxxxxxxx>
> > > > >
> > > > > Add Allwinner kconfig option which selects SoC specific and common
> > > > > drivers that is required for this SoC.
> > > > >
> > > > > Allwinner D1 uses custom PTE attributes to solve non-coherency SOC
> > > > > interconnect issues for dma synchronization, so we set the default
> > > > > value when SOC_SUNXI selected.
> > > > >
> > > > > Signed-off-by: Liu Shaohua <liush@xxxxxxxxxxxxxxxxx>
> > > > > Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> > > > > Signed-off-by: Wei Fu <wefu@xxxxxxxxxx>
> > > > > Cc: Anup Patel <anup.patel@xxxxxxx>
> > > > > Cc: Atish Patra <atish.patra@xxxxxxx>
> > > > > Cc: Christoph Hellwig <hch@xxxxxx>
> > > > > Cc: Chen-Yu Tsai <wens@xxxxxxxx>
> > > > > Cc: Drew Fustini <drew@xxxxxxxxxxxxxxx>
> > > > > Cc: Maxime Ripard <maxime@xxxxxxxxxx>
> > > > > Cc: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>
> > > > > Cc: Wei Wu <lazyparser@xxxxxxxxx>
> > > > > ---
> > > > >    arch/riscv/Kconfig.socs      | 15 +++++++++++++++
> > > > >    arch/riscv/configs/defconfig |  1 +
> > > > >    2 files changed, 16 insertions(+)
> > > > >
> > > > > diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
> > > > > index 30676ebb16eb..8721c000ef23 100644
> > > > > --- a/arch/riscv/Kconfig.socs
> > > > > +++ b/arch/riscv/Kconfig.socs
> > > > > @@ -70,4 +70,19 @@ config SOC_CANAAN_K210_DTB_SOURCE
> > > > >
> > > > >    endif
> > > > >
> > > > > +config SOC_SUNXI
> > > > > +     bool "Allwinner SoCs"
> > > > > +     depends on MMU
> > > > > +     select DWMAC_GENERIC
> > > > > +     select ERRATA_THEAD
> > > > > +     select RISCV_DMA_NONCOHERENT
> > > > > +     select RISCV_ERRATA_ALTERNATIVE
> > > > > +     select SERIAL_8250
> > > > > +     select SERIAL_8250_CONSOLE
> > > > > +     select SERIAL_8250_DW
> > > > > +     select SIFIVE_PLIC
> > > > > +     select STMMAC_ETH
> > > > > +     help
> > > > > +       This enables support for Allwinner SoC platforms like the D1.
> > > > > +
> > > >
> > > > I'm not sure we should select the drivers there. We could very well
> > > > imagine a board without UART, or even more so without ethernet.
> > > We just want people could bring D1 up easier, 8250 is the basic component.
> > >
> > >
> > > > These options should be in the defconfig.
> >
> > Agreed, using a defconfig is the right way to do this.
> Put 8250 related configs into arch/riscv/configs/defconfig?
>
>   @Palmer Dabbelt @Arnd Bergmann, How do you think about that?
> (defconfig or Kconfig.soc)
> My purpose is when people make the Image from riscv/defconfig, then
> the Image could run on all platforms include D1.

Hi,

I certainly did not understand your purpose with the patch being
able to build a kernel that would run on multiple platforms.
Still, I would not expect to see one platform cause unnecessary
drivers to be built for platforms that don't need them.

Kconfig.socs in arch/riscv/ is a bit of an unusual Kconfig file
IMO -- I suppose what you want to do fits into its style.

AFAIK the suggestion to use a defconfig (at least my suggestion)
was expecting to have a defconfig for each platform, but that
would not give you a boot image that could run on all platforms.

Anyway, it's Palmer's choice.

thanks.
--
~Randy