[U-Boot] Uboot send pull request

[Bin Meng]

Hi Rick,

On Wed, Nov 21, 2018 at 2:00 PM Rick Chen <rickchen36 at gmail.com> wrote:
>
> > >
> > > Do any of your above patches get v2 posted? At least I did not see any follow-up
> > > response [1] regarding to "riscv: ax25-ae350: Pass dtb address to u-boot with a1
> > > register"
>
> First of all you told me about that
> board_fdt_blob_setup() should be completely removed.
> Instead the simple fix should be add CONFIG_OF_PRIOR_STAGE
> to ax25-ae350_defconfig.
>
> Then I explain you about that is for booting from flash.
> And you said
> In this case, we need support OF_CONTROL like other arch, eg:
> CONFIG_OF_EMBED and CONFIG_OF_SEPARATE.
>
> In README, I don't find the limitation about when booting from flash,
> it can not use  CONFIG_OF_BOARD.
>

Correct. However, when ax25-ae350's U-Boot boots from ROM, where does
prior_stage_fdt_address get assigned to the ROM address? Besides, this
variable is declared in fdtdec.h as follows:

#if CONFIG_IS_ENABLED(OF_PRIOR_STAGE)
extern phys_addr_t prior_stage_fdt_address;
#endif

It means only OF_PRIOR_STAGE will use this variable. But in your patch
this was borrowed to support OF_BOARD, which is confusing I think. If
U-Boot boots from reset vector, the canonical way to support DT is via
CONFIG_OF_EMBED or CONFIG_OF_SEPARATE.

> That is why ax25-ae350 use
> CONFIG_OF_BOARD to support boot from RAM and ROM.
> It is a flexible approach to meet Andes' HW mechanism.
>
> I think it is a configuration in ax25-ae350_defconfig.
> It will not affect qemu-riscv32(64)_defconfig.
>

I understand it does not affect qemu riscv board. The thing is that I
wasn't clear why you did that way for ax25-ae350.

> That is why I do not prepare v2 to modify it as
> CONFIG_OF_EMBED or CONFIG_OF_SEPARATE
> as your willingness.
>

Regards,
Bin