On 06/10/2023 16:26, Köry Maincent wrote: > On Wed, 4 Oct 2023 15:39:23 +0300 > Roger Quadros <[email protected]> wrote: > > Hello, > Thanks for adding me in cc. Also it seems I forgot to add myself to > MAINTAINERS > for the extension_board.c file. > >>>>> Before this goes too far I think this should move to using a linker >>>>> list to declare the driver (or a driver-model driver if you prefer, >>>>> but that might be overkill). >> >> So I've been working on this on the side and got linker list way working >> with custom script booting but as soon as I move to standard boot flow >> it no longer works. This is because there is no code in place to >> apply the overlay and pass it to next stage e.g. EFI. >> >> I see the following note at >> https://elixir.bootlin.com/u-boot/latest/source/boot/bootmeth_efi.c#L304 >> >> " >> /* >> * TODO: Apply extension overlay >> * >> * Here we need to load and apply the extension overlay. This >> is >> * not implemented. See do_extension_apply(). The extension >> * stuff needs an implementation in boot/extension.c so it is >> * separate from the command code. Really the extension stuff >> * should use the device tree and a uclass / driver interface >> * rather than implementing its own list >> */ >> " > > I agreed that the extension implementation should move in boot/extension.c or > common for general use. I am wondering what the advantage of creating an > uclass > interface? > I am not an uclass expert but there is no per driver ops and usage. What do > you > dislike about using its own list?
There would be per platform ops for probing the extension cards in a platform specific way. I already have a linker list way of doing this but stumbled upon Simon's comments about using uclass for this. > >> Another note at >> https://elixir.bootlin.com/u-boot/latest/source/cmd/extension_board.c#L198 >> >> "/* extensions should have a uclass - for now we use UCLASS_SIMPLE_BUS uclass >> */" >> >> So are we better off implementing a class driver for extension stuff? > > I think the first point should be to move it in common or boot and makes it > generic for using the extension function everywhere. I will let Simon answer > about the uclass part. > > Regards, -- cheers, -roger
