[meta-xilinx] Zynq NAND Flash support in U-Boot SPL

[Richard Cagley]

On Tue, Feb 21, 2017 at 1:05 PM, Oleg K Dzhimiev <oleg at elphel.com> wrote:
> Hi,
>
>> Within my krogoth/yocto build I get several files and it is confusing
>> which to use.
>> I have a boot.bin (fsbl/bit/u-boot.elf) I generate/program in SDK and
>> that works fine.
>>
>> If I'd like to program NAND from within u-boot via say booting from an
>> SD card, do you have a recommendation for which files to use? I've
>> patched u-boot with my ps7 files and have CONFIG_SPL=y. Should I use
>> SPL or is there a way to program my existing boot.bin directly?
>
>
> 1. If you are able to load the full u-boot then it doesn't matter what was
> used - fsbl or spl.
> To be able to write to NAND, you might need to include into the full u-boot
> image:
> * a driver that supports the flash chip.
> * flash commands support  - example: elphel393.h. For the commands, see
> UBootCmdGroupNand.
>
spl is still a complete mystery to me. I wish I could figure out which
files to use.

> With our 10393 board I tried NAND reading/writing a while ago but since then
> we program flash from OS (booted from SD or NAND) only.
> To be able to do this - make sure the required applications are included in
> the rootfs - our current rootfs recipe. Commands examples.
>
> 2. If your goal is to put the bootloaders to NAND flash and eventually boot
> from it:
> fsbl:
> * Haven't used it for a while - don't know whether it can load the full
> u-boot from flash.
> spl:
> * Make sure it comes with a driver to read from flash - we had to make our
> own.
>
thanks. yeah, I just use fsbl/u-boot to boot from NAND and then use
the ubi commands to manage everything else from within u-boot. thanks
for sharing your bb file. Mine looks very similar but it was still
good to validate against someone else's.