ZynqMP boot: no messages from SPL other than "Debug uart enabled"

[Major A]

Hi Michal,

> First of all I sent v2 because of dt changes to see 1.1 revision and I
> have also tested it on real HW.

Just tried your patch v2 against mainline master branch, it still 
doesn't work on my board.  I also checked your mainline-v20200312 
branch, it's exactly the same: no output from any UART other than "Debug 
uart enabled" on UART0 if I enable it in menuconfig as "early UART".

>> For some reason, that's no enough: I have to manually set
>> CONFIG_DEVICE_TREE because xilinx_zynqmp_virt_defconfig sets it wrong.
>> In any case, behaviour is exactly the same as before.
> 
> With latest my queue it should be enough.
> https://github.com/michalsimek/u-boot/tree/mainline-v20200312

It's the same.  CONFIG_DEFAULT_DEVICE_TREE becomes "zynqmp-zcu100-revC" 
whatever I do, there is no trace of the value specified in the 
DEVICE_TREE environment variable.

> But I think that latest mainline should setup default in ITS properly.
> You can check it by looking at u-boot.its when build is done and find
> default configuration option which should point to 1.1 dt.

 From the build using your mainline-v20200312 branch:

   default = "config_1";

where config_1 is

   description = "avnet-ultra96-rev1";

> Here are jtag steps I have run.

I haven't set up JTAG yet.

Cheers,

   András