Hi, On Tue, 7 Nov 2023 at 15:38, Tom Rini <tr...@konsulko.com> wrote: > > On Tue, Nov 07, 2023 at 10:27:50PM +0000, Conor Dooley wrote: > > On Tue, Nov 07, 2023 at 05:10:23PM -0500, Tom Rini wrote: > > > > > > > further clarify or not > > > the RISC-V ISA thing that's elsewhere in this thread (and part of the > > > kernel, not a U-Boot thing). > > > > TBH, this a bit fragmented across threads, and as someone that hasn't > > been following it it's a bit difficult to tell exactly what is being > > asked for. Would someone be able to ask it as a direct question? > > Sorry for being unclear, and thanks for asking. What I think the U-Boot > community would like to know is, what is the device-tree based way to > know if a RISC-V platform has the Zbb extensions and so the RNG opcodes, > similar (in concept at least?) to the ARMv8.5 RNG feature.
Some more details (sorry) from your friendly devicetree and driver model maintainer: - U-Boot models hardware (and other things) as devices in driver model [1] - U-Boot requires devices to be in the devicetree, with very limited exceptions [2] - Where multiple devices exist in a uclass, it is desirable to be able to number them [3] - Similarly it is useful to be able select a particular device, e.g. with a phandle [4] - U-Boot uses devicetree for configuration as it has no userspace Regards, Simon [1] https://u-boot.readthedocs.io/en/latest/develop/driver-model/index.html [2] https://u-boot.readthedocs.io/en/latest/develop/driver-model/design.html#platform-data [3] https://u-boot.readthedocs.io/en/latest/develop/driver-model/design.html#device-sequence-numbers [4] https://u-boot.readthedocs.io/en/latest/api/dm.html?highlight=phandle#c.of_find_node_by_phandle