On 26/06/2018 13:57:12+0200, Alexandre Belloni wrote:
> Allow not building any DTB in the generic kernel so it gets smaller. This
> is necessary for ocelot because it can be built as a legacy platform that
> needs a built-in DTB and it can also handle a separate DTB once it is
> updated with a more modern bootloader. In the latter case, it is preferable
> to not include any DTB in the kernel image so it is smaller.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
> ---
> Changes in v2:
> - rebased on v4.18-rc1
>
Note that while the first patch can probably be applied as-is (it only
affects Ocelot). this one still needs to be refined. It seems to be
causing build issues with some defconfig.
> arch/mips/Kconfig | 1 -
> arch/mips/Makefile | 2 +-
> arch/mips/generic/Kconfig | 1 +
> arch/mips/generic/vmlinux.its.S | 2 ++
> 4 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index 3f9deec70b92..2cc43f51fa6f 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -85,7 +85,6 @@ choice
> config MIPS_GENERIC
> bool "Generic board-agnostic MIPS kernel"
> select BOOT_RAW
> - select BUILTIN_DTB
> select CEVT_R4K
> select CLKSRC_MIPS_GIC
> select COMMON_CLK
> diff --git a/arch/mips/Makefile b/arch/mips/Makefile
> index e2122cca4ae2..5c5d491d736e 100644
> --- a/arch/mips/Makefile
> +++ b/arch/mips/Makefile
> @@ -401,7 +401,7 @@ endif
> CLEAN_FILES += vmlinux.32 vmlinux.64
>
> # device-trees
> -core-$(CONFIG_BUILTIN_DTB) += arch/mips/boot/dts/
> +core-y += arch/mips/boot/dts/
>
> %.dtb %.dtb.S %.dtb.o: | scripts
> $(Q)$(MAKE) $(build)=arch/mips/boot/dts arch/mips/boot/dts/$@
> diff --git a/arch/mips/generic/Kconfig b/arch/mips/generic/Kconfig
> index 08e33c6b2539..13692b84928e 100644
> --- a/arch/mips/generic/Kconfig
> +++ b/arch/mips/generic/Kconfig
> @@ -3,6 +3,7 @@ if MIPS_GENERIC
>
> config LEGACY_BOARDS
> bool
> + select BUILTIN_DTB
> help
> Select this from your board if the board must use a legacy, non-UHI,
> boot protocol. This will cause the kernel to scan through the list of
> diff --git a/arch/mips/generic/vmlinux.its.S b/arch/mips/generic/vmlinux.its.S
> index 1a08438fd893..9c954f2ae561 100644
> --- a/arch/mips/generic/vmlinux.its.S
> +++ b/arch/mips/generic/vmlinux.its.S
> @@ -21,6 +21,7 @@
> };
> };
>
> +#if IS_ENABLED(CONFIG_BUILTIN_DTB)
Thinking more about that, the conf@default configuration should probably
not be removed if the platform is not using DT at all. Are there still
MIPS platforms without DT support?
> configurations {
> default = "conf@default";
>
> @@ -29,4 +30,5 @@
> kernel = "kernel@0";
> };
> };
> +#endif
> };
> --
> 2.18.0
>
--
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
