On 20 March 2012 17:14, Paul Brook <p...@codesourcery.com> wrote: >> >> Yes, I think I'd agree there. So should we just have an init function >> >> that provides the implementation-specific cp15 registers based on the >> >> value provided in the QOM property for the main ID register? >> > >> > Something like that, yes. I'm not convinced the main ID register is the >> > right property to use, but for actual implementation specific bits >> > (rather than bits where an implementation picks one of a few common >> > options) I guess we don't have any alternative but enumerating the >> > implementations we support. >> >> Mmm, the disgusting thing the TI925T has where it can programmatically >> change the value of its main ID register does somewhat argue against using >> it for this. > > I was thinking more for when we have multiple revisions of a chip that are > (for these purposes) the same. Currently we only have this for pxa, but in > principle we probably want it for others.
I had in mind that we'd do it based on the main ID with the revision/variant fields masked out, which makes all the PXA chips the same. On the other hand that also makes 1136 and 1136_R2 the same, which is a pain because they're really pretty different. > As I mentioned on IRC, this isn't particularly interesting for Linux, which > will happily run on pretty much anything. However there are other systems > that care[1] whether the core reports itself as e.g. arm1136-r0p1 v.s. > arm1136-r0p2. Yeah, I've encountered this before too. -- PMM