[U-Boot] [RFC PATCH 0/3] sunxi: extend SPL header to propagate DRAM size

[Icenowy Zheng]

于 2018年5月17日 GMT+08:00 下午4:16:58, Andre Przywara <andre.przywara at arm.com> 写到:
>This series tries to solve three issues we currently have on
>Allwinner boards:
>- The DRAM sizing routine can only cope with power-of-two sized DRAM.
>- The DRAM sizing routine steps through all DRAM, possibly hitting
>secure
>  memory.
>- The SPL header versioning is quite strict and tends to break every
>time
>  we need to update it.
>
>So I thought about introducing something along the lines of semantic
>versioning[1], where we can add backwards-compatible changes to the SPL
>header without breaking every tool. This is introduced in the first

How to define the "backwards-compatible"?

Should it have a standard? (e.g. tools have no change needed
and U-Boot will have fallback code)

>patch.
>The second patch does some refactoring, so that the third patch can use
>the newly gained freedom to store the DRAM size. The SPL knows the DRAM
>size very well, so we store this in the SPL header, so that U-Boot
>proper
>can pick it up from there. This saves the call to get_ram_size() with
>its deficiencies.
>More information in the respective commit messages.
>
>I understand that this versioning solution is not fully future-proof,
>but
>we have only one byte for the version, and I just wanted to start
>discussion on this.
>There is a corresponding patch for sunxi-tools as well I am posting
>shortly.
>
>[1] https://semver.org
>
>Cheers,
>Andre.
>
>Andre Przywara (3):
>  sunxi: Extend SPL header versioning
>  sunxi: board.c: refactor SPL header checks
>  sunxi: store DRAM size in SPL header
>
> arch/arm/include/asm/arch-sunxi/spl.h | 22 ++++++++----
>board/sunxi/board.c                   | 66
>++++++++++++++++++++++++++++-------
> 2 files changed, 70 insertions(+), 18 deletions(-)