Hi Köry, On Fri, 6 Oct 2023 at 07:26, Köry Maincent <[email protected]> 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?
I looked at this briefly for bootstd and left it alone, partly for this reason. The operations I know about are: - scan for extension boards to produce a list: needs to happen at start of 'bootflow scan' I think) - applying relevant overlays: needs to happen in the read_bootflow() method perhaps - listing available extensions I think a uclass makes sense, along with separating out the 'extension' command from the actual functionality. > > > 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. I believe this relates to boot/ > > Regards, Regards, Simon
