Applying DTB Overlays from ATF on RZ/G2

[Heinrich Schuchardt]

On 1/4/23 22:35, Adam Ford wrote:
> ATF generates a couple memory nodes based on how it's compiled and
> generates a reserved-memory node, and I want to overlay it with the
> device tree so Linux knows about this reserved memory.
>
> When I boot U-Boot, I can read the reserved-memory node:
>
> => fdt addr 0xe631e588
> Working FDT set to e631e588
> => fdt print /reserved-memory
> reserved-memory {
> lossy-decompression at 54000000 {
> renesas,formats = <0x00000000>;
> no-map;
> reg = <0x00000000 0x54000000 0x00000000 0x03000000>;
> compatible = "renesas,lossy-decompression", "shared-dma-pool";
> };
> };
> =>
>
> I attempt to overlay it with the following:
>
> => run loadfdt
> 65932 bytes read in 6 ms (10.5 MiB/s)
> => fdt addr $load_addr

When actually setting the address you will see a message "Working FDT
set to %lx\n". So I assume $load_addr is empty.

Did you mean $loadaddr or $fileaddr?

> Working fdt: e631e588
> => fdt resize 8192
> => fdt apply 0xe631e588

Here you are apply the devicetree at e631e588 to itself which cannot work.

Best regards

Heinrich

>
> At this point, I would expect the reserved-memory node to be merged
> with the main FDT, but it appears to be missing.
>
> => fdt print /reserved-memory
> libfdt fdt_path_offset() returned FDT_ERR_BADMAGIC
> =>
>
> There are no errors, but there are no overlays either.
>
> Does someone have any suggestions as to what I am doing wrong?
> Without the reserved memory node, Linux can crash if it tries to use
> the memory in that restricted area, and that node might change
> depending on how ATF is compiled.
>
> Thanks for any help.
>
> adam