[U-Boot] [PATCH] arm64: spin-table: add more information in Kconfig help

[Oded Gabbay]

On Thu, Jan 19, 2017 at 2:07 PM, Masahiro Yamada
<yamada.masahiro at socionext.com> wrote:
> This feature seems to be sometimes misunderstood.  The intention is
>
> [1] Bring the slaves into U-Boot proper image, not SPL (unless
>     you have a special reason).
>
> [2] The operation must be done in a board (SoC) specific manner
>     since how to wake the slaves from the Boot ROM is SoC specific.
>
> [3] The slaves must enter U-Boot proper after U-Boot relocates
>     itself because the "cpu-release-addr" property points to the
>     relocated memory area.
>
> [2] is already explained in the help.  We can make [1] even clearer
> by mentioning "U-Boot proper" instead of "U-Boot".  [3] is missing,
> so I am adding it to the list.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
> ---
>
>  arch/arm/cpu/armv8/Kconfig | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/cpu/armv8/Kconfig b/arch/arm/cpu/armv8/Kconfig
> index 22dce88..7388eca 100644
> --- a/arch/arm/cpu/armv8/Kconfig
> +++ b/arch/arm/cpu/armv8/Kconfig
> @@ -12,8 +12,11 @@ config ARMV8_SPIN_TABLE
>           To use this feature, you must do:
>             - Specify enable-method = "spin-table" in each CPU node in the
>               Device Tree you are using to boot the kernel
> -           - Let secondary CPUs in U-Boot (in a board specific manner)
> -             before the master CPU jumps to the kernel
> +           - Bring secondary CPUs into U-Boot proper (in a board specific
> +             manner) before the master CPU jumps to the kernel, but *after*
> +             relocation.  Otherwise, the master CPU will see a different copy
> +             of the spin code, then the secondary CPUs will spin in the
> +             unprotected memory area.
>
>           U-Boot automatically does:
>             - Set "cpu-release-addr" property of each CPU node
> --
> 2.7.4
>
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot

This patch is:
Reviewed-by: Oded Gabbay <oded.gabbay at gmail.com>