On Tue, Aug 07, 2007 at 06:58:20PM +0200, Segher Boessenkool wrote: > >> Most characters are allowed in the unit-address... The following > >> is just fine: "[EMAIL PROTECTED]". ISA uses letters to > >> distinguish between its different address spaces, for example. > > > > Yeah, I should probably make dtc a bit more flexible about accepting > > that, too. At present, it only takes hex digits and ',', since those > > are the common character. > > Sounds good. And then the legacy ISA devices in existing > DTS files should be changed to say @i60 instead of @60, etc. > (@60 is correct since the default is legacy I/O space, but > it's good the be more verbose in those cases).
Ok, I'll look into that. No promises that it will be real soon, though. > >> David, can multiple devices sit on the same chip-select > >> on EBC, or on the same "minor" address? If not, you can > >> simplify your unit address representation. > > > > As far as I know, multiple devices could sit on the same chip select: > > provided there was enough address decoding logic in or around the > > devices, and that there existing bus timing parameters which would > > work with all the devices on a chip select (or "bank" in the > > terminology of the EBC bridge documentation). > > Ah, that's what multiple banks are for! Yes. > > Devices on different banks can certainly have the same address/offset > > within the bank - e.g. on Ebony most of the devices are at offset 0. > > The OPB address range for each bank is separately programmable in the > > EBC bridge DCRs. > > Okay, seems like the <bank,offset> representation is the simplest > possible, then. Good. <rubber stamp> Excellent. I should really do a proper write-up for b-o-f.txt, I guess. > > (Incidentally, this is why I created the binding in this way, rather > > than just using the firmware established addresses in OPB space, which > > are usually fixed for a particular board/platform. This way provides > > enough information that, if necessary, the kernel or another client > > can reprogram the EBC from scratch to access the various devices > > present. Well.. actually fully reprogramming would also need the the > > bus timing parameters, which I was thinking of adding information > > before, but I haven't gotten to it yet.) > > It gives a full "as simple as possible but no simpler" description > of the hardware, so it's just fine independent of whether you want > to reprogram the EBC or not. That was the idea. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev