Hi Mark,
On Wed, Sep 29, 2021 at 02:59:10PM +0200, Mark Kettenis wrote:
[...]
I was wondering if we need to check CONFIG_OF_BOARD here? I'm not sure whether we should distinguish the value of a1 register which is
Yes, it seems to me that we could use a config to separate the case between the prior stage and the _end.
Untangling OF_SEPARATE and OF_BOARD is part of a bigger revamp I wanted to do on the handover of a device tree from previous bootloaders, since we do have similar 'problems' in Arm and TF-A. But in principle OF_SEPARATE shouldn't have per board code to overwrite it. OF_BOARD should be used for that. OF_SEPARATE should merely mean "The dtb is concatenated to my U-Boot binary.
Right now RISC-V uses OF_SEPARATE reads the DTB on SPL and then goes back to using the a1 register for U-Boot proper. We could instead read the U-Boot concatenated DTB always in that case. OF_BOARD would then be used in case OpenSBI is compiled with a *different* DTB and you'd want to use that. Any idea if OpenSBI performs fixups before handing over the dtb in a1?
It does. One of the things it does is add a reserved memory entry for itself.
Ah lovely :(, then untangling that is not an option atm :(. We still have to keep board_fdt_blob_setup() a __weak symbol for those boards, even if OF_SEPARATE is selected.
Unfortunately I don't have a board to test apart from QEMU. Let me respin this, with a potential fix I have in mind and we can discuss further.
Just note that, there is a patch on the fly, it modifies the same snippet of code, you might need to update your code based on top of it. https://lists.denx.de/pipermail/u-boot/2021-September/460378.html
I'll reply to that and see if the _end is indeed a problem.
Thanks /Ilias
Thanks /Ilias