Applying DTB Overlays from ATF on RZ/G2

[Adam Ford]

On Wed, Jan 4, 2023 at 5:55 PM Marek Vasut <marex at denx.de> wrote:
>
> On 1/5/23 00:48, Heinrich Schuchardt wrote:
> > Am 5. Januar 2023 00:19:36 MEZ schrieb Adam Ford <aford173 at gmail.com>:
> >> On Wed, Jan 4, 2023 at 5:15 PM Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> >>>
> >>> 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?
> >>
> >> Opps, that was a copy-paste error.  Even with that, I still get the
> >> failure to overlay:
> >>
> >
> > Did you load a .dtbo file to apply? You cannot apply a devicetree.
> >
> > Is the fdt that you want to apply the overlay to built with symbols (dtc parameter -@)?
>
> Note that the fragment passed to U-Boot by upstream ATF is already
> automatically merged into the U-Boot control DT (see
> board/renesas/rcar-common/common.c ) . U-Boot should pass that on to
> Linux automatically.

I ran some tests, and it appears the function fdtdec_board_setup is
never getting called.  That looks like the code that grabs the blob
from ATF.  I intentionally removed the memory nodes from the kernel
device tree expecting the memory nodes to get added from ATF, but when
I booted it, it promptly hung.  That implied to me that the memory
nodes didn't get added from ATF.

I added some debug code and noticed that ft_board_setup did not get
executed, so I created a call to fdtdec_board_setup from
ft_board_setup and my board booted just fine.  I am curious to know if
other rcar/rzg2 boards are seeing something similar?  Is calling
fdtdec_board_setup from ft_board_setup appropriate?

adam