[U-Boot] RFC - how to support multipl DRAM chips in a single SPL build?

[Wolfgang Denk]

Dear Peter Barada,

In message <4F57A37C.8070501 at logicpd.com> you wrote:
> I'm trying to build a single SPL/u-boot that supports multiple Logic
> OMAP 35x/37x boards, with multiple configurations of DRAM/NAND/NOR. 

On ARM this is still not not exactly a rampant feature (and some
[mostly ARM] SoCs try to be clever and makeit extra hard for you),
but for a large number of boards this has been a standard feature
right since the beginning of U-Boot (and PPCBoot) twelf years ago.

> This is to make our support/production much simpler, and allow one
> SPL/u-boot "just work" on all or various boards.  To do so I need to
> figure out:
> 
> 1) Probe for different DDR/NAND chips
...
> 2) Probe for multiple configurations of NOR/NAND
...

This is what get_ram_size() is good for.

> Any suggestions on an approach are much appreciated!

The normal approach is: set a configuration, run get_ram_size(), and
store the detected size. Repeat for all configurations. The
configuration that results in the biggest detected RAM size is the
correct one.

Best regards,

Wolfgang Denk

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