[U-Boot] SPL and DM on ZYNQ

[Hannes Schmelzer <hannes@schmelzer.or.at>]

> I've now branched from u-boot-dm.git/zynq-working2 and then merged 
> u-boot-spi/master into it.
>
> After a few merge conflicts i'am able to build u-boot and boot it from 
> SD with working DM support during SPL and QSPI support.
> The next step was/is burning this file into the QSPI flash and boot 
> from it.
>
> burning was now problem, but boot ends up with:
>
> U-Boot SPL 2015.10-rc4-00101-gb6dcb3f-dirty (Oct 08 2015 - 08:42:53)
> qspi boot
> boot device - 8
> uclass_find_device_by_seq: 0 0
>    - not found
> uclass_find_device_by_seq: 1 0
>    - not found
> Invalid bus 0 (err=-19)
> SPI probe failed.
> ### ERROR ### Please RESET the board ###
>
> maybe there is yet another switch, which needs to be turned on.
> Subject of suspicion is currently "support simple-bus driver in SPL". 
> But if i compile with this option,
> boot ends up with:
>
> U-Boot SPL 2015.10-rc4-00101-gb6dcb3f-dirty (Oct 08 2015 - 09:01:35)
> mmc boot
> boot device - 1
> mmc_init: 0, time 58
> spl: mmc boot mode: fs
> reading system.dtb
> Error: allocating memory
> spl_load_image_fat_os: error reading image system.dtb, err - -1
> reading u-boot-dtb.img
> Error: allocating memory
> spl_load_image_fat: error reading image u-boot-dtb.img, err - -1
> spl: mmc: no boot mode left to try
> ### ERROR ### Please RESET the board ###
This is because there is only very limited heap (0x1000) enabled in 
zynq-common.h and therefore the FAT buffers cannot be allocated -> solved.

Further i've found out that my board isn't booting from SPI because 
there  is nothing within "SPL-devicetree" about QSPI.

Can anyone explain me how the "normal" and the "SPL" devicetree is 
separated ?

best regards,
Hannes