Hi, On 13/07/2023 21:44, Nishanth Menon wrote: > On 15:29-20230711, Roger Quadros wrote: >> Hi Simon, >> >> On 10/07/2023 22:45, Simon Glass wrote: >>> Hi Roger, >>> >>> On Mon, 10 Jul 2023 at 08:51, Roger Quadros <rog...@kernel.org> wrote: >>>> >>>> Support the Expansion cards via Extension framework. >>>> This should make 'expansion' command work to scan >>>> for expansion cards and apply DT overlays. >>>> >>>> Card detection code is moved to a library so >>>> other boards can benefit from it. >>>> >>>> Signed-off-by: Roger Quadros <rog...@kernel.org> >>>> --- >>>> board/ti/am65x/evm.c | 264 ++++++++--------------------- >>>> board/ti/common/Kconfig | 8 + >>>> board/ti/common/Makefile | 1 + >>>> board/ti/common/ti_card_detect.c | 155 +++++++++++++++++ >>>> board/ti/common/ti_card_detect.h | 43 +++++ >>>> configs/am65x_evm_a53_defconfig | 2 + >>>> configs/am65x_hs_evm_a53_defconfig | 2 + >>>> 7 files changed, 280 insertions(+), 195 deletions(-) >>>> create mode 100644 board/ti/common/ti_card_detect.c >>>> create mode 100644 board/ti/common/ti_card_detect.h >>> >>> 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 */ " 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? Once that is in place how should extension apply work? Current implementation relies on a extension_overlay_cmd environment to be specified. e.g. for EFI boot case, the overlay files should be obtained in the same way we get the base device tree i.e. bootmeth_common_read_file()? -- cheers, -roger
