Messages in this thread | | | From | Arnd Bergmann <> | Date | Tue, 14 Sep 2021 11:29:41 +0200 | Subject | Re: [RFC PATCH V4 6/6] riscv: soc: Add Allwinner SoC kconfig option |
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On Tue, Sep 14, 2021 at 4:36 AM Guo Ren <guoren@kernel.org> wrote: > On Tue, Sep 14, 2021 at 2:49 AM Randy Dunlap <rdunlap@infradead.org> wrote: > > On 9/13/21 2:20 AM, Guo Ren wrote: > > > On Mon, Sep 13, 2021 at 4:45 PM Maxime Ripard <maxime@cerno.tech> wrote: > > >> On Sat, Sep 11, 2021 at 05:21:39PM +0800, guoren@kernel.org wrote: > > >>> From: Liu Shaohua <liush@allwinnertech.com> > > >>> > > >>> 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. > > >>> > > >>> > > >>> +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?
I think that would be best, as well as the STMMAC_ETH and DWMAC_GENERIC options.
If all RISC-V chips are required to have a 8250 compatible uart, selecting it from CONFIG_RISCV would work as well, but for consistency I'd give users the option to leave it out, just like any other driver that is not required to have a useful system.
> @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.
I would try to keep the Kconfig.soc as short as possible. As a general rule, only use 'select' to enable symbols that are otherwise not user visible, such as the specific errata if you want to hide them. For individual SoCs, I prefer not having separate Kconfig options, but instead have those per driver. We have some SoC families that have part specific options elsewhere, e.g. drivers/soc/renesas/Kconfig, but I'd only add those if you can't avoid it. Having it in drivers/soc/ may be better for sunxi than spreading them over arch/{arm,arm64,riscv}.
Some subsystem maintainers want drivers to be selected by the SoC option, this is why you need the 'select SIFIVE_PLIC', but usually the drivers are selectable with a 'depends on ARCH_SUNXI || COMPILE_TEST' and enabled in the defconfig.
If you want to get fancy, you can use something like:
config RESET_SUNXI bool "Allwinner SoCs Reset Driver" if COMPILE_TEST && !ARCH_SUNXI default ARCH_SUNXI
This will make an option that - always enabled when the platform is built-in - user selectable when compile-testing for any other platform - always disabled otherwise
Arnd
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