[Buildroot] [PATCH] Add support for Digilent Zybo (Xilinx Zynq-7000)

[Sebastien Van Cauwenberghe <svancau@gmail.com>]

Hi Thomas, list,

>>> Also, why do you use an initramfs for the rootfs rather than the more
>>> traditional ext4 partition next to the FAT partition? This would be the
>>> preferred method for the defconfig in Buildroot.
>>>  
>> I will go to ext4 but (as a beginner), I'll first investigate what is wrong with ext4
>> not booting (maybe mmc/ext4 compiled as a module).
>>
Inadequate bootargs were used, now it works without changing defconfig.

>>>> +There is a patch attached that redefines the U-Boot's environment
>>>> +to work with Buildroot out-of-the-box.  
>>>
>>> Why do you patch the U-Boot built-in environment instead of providing
>>> an uEnv.txt file?
>>>
>> I saw loading uEnv.txt was a board specific stuff and should be subject to patch anyways
>> so I added the environment in there so I can use the board without sd card but with 
>> the flash memory.
> 
> So the default environment is not already loading a uEnv.txt file or
> executing some default script from the MMC ?
> 
> If that's the case, then indeed, you need to patch the default
> environment.
> 
I'll give a try to use uEnv.txt as it's also in the common Zynq configurations.
I just hope it's not loaded too late, otherwise, patch it will be :).

>>>
>>> Can you try to use zImage instead, which is now the standard format on
>>> ARM?
>>>  
>> Apparently the uImage is all I can use easily with the Zynq, maybe with another
>> defconfig in U-boot for this board, I'll be able to use zImages ?
> 
> Hum, you really don't have the "bootz" command in U-Boot? For a modern
> U-Boot, this seems weird.
It's in U-boot but not enabled in the defconfig for this board, so I don't know which
is better, change the defconfig U-boot or just live with the uImage instead of zImage.
Or maybe FIT image ? I just don't know what to use...

Thanks for your time
S?bastien