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    SubjectRe: [PATCH v2 25/35] nds32: Build infrastructure
    2017-11-29 17:25 GMT+08:00 Arnd Bergmann <arnd@arndb.de>:
    > On Wed, Nov 29, 2017 at 10:10 AM, Geert Uytterhoeven
    > <geert@linux-m68k.org> wrote:
    >> Hi Arnd,
    >>
    >> On Wed, Nov 29, 2017 at 9:58 AM, Arnd Bergmann <arnd@arndb.de> wrote:
    >>> On Wed, Nov 29, 2017 at 9:39 AM, Greentime Hu <green.hu@gmail.com> wrote:
    >>>> 2017-11-27 22:21 GMT+08:00 Arnd Bergmann <arnd@arndb.de>:
    >>>>> On Mon, Nov 27, 2017 at 1:28 PM, Greentime Hu <green.hu@gmail.com> wrote:
    >>>>>> diff --git a/arch/nds32/Kconfig.cpu b/arch/nds32/Kconfig.cpu
    >>>>>> +config CPU_CACHE_NONALIASING
    >>>>>> + bool "Non-aliasing cache"
    >>>>>> + help
    >>>>>> + If this CPU is using VIPT data cache and its cache way size is larger
    >>>>>> + than page size, say N. If it is using PIPT data cache, say Y.
    >>>>>> +
    >>>>>> + If unsure, say Y.
    >>>>>
    >>>>> Can you determine this from the CPU type?
    >>>>
    >>>> There is no cpu register to determine it. It also depeneds on page
    >>>> size and way size however page size is configurable by software.
    >>>> These codes are determined at compile time will be benefit to code
    >>>> size and performance.
    >>>> IMHO, I think it would be better to be determined here.
    >>>
    >>> I meant determining it at compile time from other Kconfig symbols,
    >>> if that's possible. Do the CPU cores each have a fixed way-size?
    >>> If they do, it could be done like
    >>>
    >>> menu "CPU selection"
    >>>
    >>> config CPU_N15
    >>> bool "AndesCore N15"
    >>> select CPU_CACHE_NONALIASING
    >>>
    >>> config CPU_N13
    >>> bool "AndesCore N15"
    >>> select CPU_CACHE_NONALIASING if PAGE_SIZE_16K
    >>>
    >>> ...
    >>>
    >>> endmenu
    >>>
    >>> and then you can use the same CPU_... symbols to make other decisions
    >>> as well, e.g. CPU specific compiler optimizations.
    >>
    >> Do you want to support multiple CPU types in a single kernel image
    >> (I see no "choice" statement above)?
    >> If yes, you may have a mix of aliasing and non-aliasing caches, so
    >> you may want to invert the logic, and select CPU_CACHE_ALIASING
    >> instead.
    >
    > Right, my mistake.
    >

    Thanks to Arnd and Geert!

    How about this?

    choice
    prompt "CPU type"
    default CPU_N13
    config CPU_N15
    bool "AndesCore N15"
    select CPU_CACHE_NONALIASING
    config CPU_N13
    bool "AndesCore N13"
    select CPU_CACHE_NONALIASING if ANDES_PAGE_SIZE_8KB
    config CPU_N10
    bool "AndesCore N10"
    select CPU_CACHE_NONALIASING if ANDES_PAGE_SIZE_8KB
    config CPU_D15
    bool "AndesCore D15"
    select CPU_CACHE_NONALIASING
    select HWZOL
    config CPU_D10
    bool "AndesCore D10"
    select CPU_CACHE_NONALIASING if ANDES_PAGE_SIZE_8KB
    endchoice

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