[U-Boot] [PATCH v2 23/23] sunxi: A64: add 32-bit SPL support

[Simon Glass]

Hi Andre,

On 4 December 2016 at 18:52, Andre Przywara <andre.przywara at arm.com> wrote:
> When compiling the SPL for the Allwinner A64 in AArch64 mode, we can't
> use the more compact Thumb2 encoding, which only exists for AArch32
> code. This makes the SPL rather big, up to a point where any code
> additions or even a different compiler may easily exceed the 32KB limit
> that the Allwinner BROM imposes.
> Introduce a separate, mostly generic sun50i-a64 configuration, which
> defines the CPU_V7 symbol and thus will create a 32-bit binary using
> the memory-saving Thumb2 encoding.
> This should only be used for the SPL, the U-Boot proper should still be
> using the existing 64-bit configuration. The SPL code can switch to
> AArch64 if needed, so a 32-bit SPL can be combined with a 64-bit U-Boot
> proper to eventually launch arm64 kernels.

So if I understand correctly, you want SPL to be 32-bit and U-Boot
proper to be 64-bit? And you are adding a new board config for that?

Instead, can you do something similar to tegra, which uses ARMv4t for
SPL and ARMv7 for U-Boot proper?

>
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
>  board/sunxi/Kconfig            | 14 ++++++++++++--
>  configs/pine64_plus_defconfig  |  2 +-
>  configs/sun50i_spl32_defconfig | 10 ++++++++++
>  include/configs/sunxi-common.h |  2 +-
>  4 files changed, 24 insertions(+), 4 deletions(-)
>  create mode 100644 configs/sun50i_spl32_defconfig

Regards,
Simon