[U-Boot] [PATCH 06/11] MX6: add struct for sharing data between SPL and uboot

[Tim Harvey <tharvey@gateworks.com>]

On Mon, Apr 14, 2014 at 5:35 AM, Stefano Babic <sbabic@denx.de> wrote:
> Hi Tim,
>
> I see checking your patch that the MXS uses the same concept. And as far
> as I can see, boot_mode_idx is used only to print the boot devioce

Stefano,

yes, that is where I got the concept from.

>
> However, we have not generally a concept to pass data between SPL and
> u-boot. My question is even if it is really needed. The size of DRAM is
> retrived at run time by u-boot running get_ram_size(), that is a better
> solution.

I've been told this before, but I've found that get_ram_size() will
hang on an i.MX6 if you pass it a maxsize larger than the memory in
your system. Perhaps you can verify you see the same behavior?

>
> SPL is thought to generally load an image (of course, in most cases it
> is u-boot). In Falcon mode, the kernel is started without running
> u-boot, making this structure useless. Do we really need such a way (but
> then, it must be generalized as SPL API), or can we get rid of it ?

As we have an EEPROM on the board that tells us the physical ram size,
I use that to avoid the lockup. Eventually I would like to read and
validate the entire EEPROM once in SPL and pass this to u-boot.img to
avoid reading and validating it again. I think this is a good example
of why sharing data between SPL and u-boot.img could be useful.

Regards,

Tim