Date: Wed, 18 Aug 1999 17:00:56 +0100 (BST) From: Doug Rabson <dfr@nlsystems.com> To: Peter Wemm <peter@netplex.com.au> Cc: alpha@freebsd.org Subject: Re: rman_get_virtual() on alpha Message-ID: <Pine.BSF.4.10.9908181659030.72739-100000@salmon.nlsystems.com> In-Reply-To: <19990818144402.DC8091C99@overcee.netplex.com.au>
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On Wed, 18 Aug 1999, Peter Wemm wrote: > Doug Rabson wrote: > > On Wed, 18 Aug 1999, Peter Wemm wrote: > > > > > So, what's the situation these days with rman_get_virtual()? if_fxp explod > es > > > on the alpha because it allocates SYS_RES_MEMORY and wants the virtual > > > address of it, but the alpha still is returning physical addresses it seems > . > > > > > > It seems to me we might need some alternative to rman_get_virtual since it > > > doesn't have enough context and is just a hack. Perhaps allocating memory > > > and activating a mapping etc needs to be seperate bus methods? That way we > > > can allocate memory, and later activate it (pmap_mapdev on x86, BWX, or > > > DENSE on Alpha as requested) and free it's kvm mappings? > > > > The fxp driver should probable use SYS_RES_DENSE to get the right virtual > > pointer. It would certainly be a lot cleaner to separate the resource > > allocation from the virtual mapping. > > The question is though, allocating memory resources on the alpha - does it > depend on the mapping type (dense vs. bwx)? Or is that decision better > left to mapping time? And can we fit this in with bus_space etc? (NetBSD > has a bus_space_map() function to map bus space into kvm, maybe we need a > parallel to that such that we don't have to expose DENSE/BWX etc mappings > to drivers). Or maybe map it in both dense and bwx space and let bus_space > use whichever method is convenient? There is no actual overhead for 'mapping' the resources since we just point at the right part of the direct physical->virtual mapped segment. The main issue as I see it is that the existing mechanism is ugly. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 442 9037 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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