Hi Palmer, On Mon, Nov 20, 2017 at 01:28:01PM -0800, Palmer Dabbelt wrote: > On Mon, 20 Nov 2017 12:28:56 PST (-0800), j.neuschaefer@xxxxxxx wrote: > > On Mon, Nov 20, 2017 at 11:50:00AM -0800, Palmer Dabbelt wrote: > > > +RISC-V Supervisor Binary Interface (SBI) > > > + > > > +The RISC-V privileged ISA specification mandates the presence of a supervisor > > > +binary interface that performs some operations which might otherwise require > > > +particularly complicated instructions. This interface includes > > > +inter-processor interrupts, TLB flushes, i-cache and TLB shootdowns, a > > > +console, and power management. > > > + > > > +Required properties: > > > +- compatible: must contain one of the following > > > + * "riscv,sbi" for the SBI defined by the privileged specification of the > > > + system. > > > > "of the system" seems to imply that different RISC-V systems (different > > RISC-V implementations) can have different privileged specifications. > > Actually, that was intentional -- I wrote it this way because different > RISC-V systems do have different privileged specifications. The RISC-V > specifications aren't frozen in time, they're just guaranteed to be > compatible in the future. If that's the case, then you can define a version of the document that is a baseline. e.g. * "riscv,sbi" for an SBI implementation compatible with that defined in $XYZ_DOCUMENT version $N If every new feature can be probed from that point onwards, then that's all you'll ever need. Otherwise, if there are backwards-incompatible changes or non-probeable features, you can add additional strings, and there's no ambiguity. See Documentation/devicetree/bindings/arm/psci.txt for an similar example on ARM systems. That's explicitly versioned, though we don't list each and every document number, and we probably should. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
