Date: Thu, 11 Sep 1997 20:02:36 +1000 From: Mike Smith <mike@smith.net.au> To: Luigi Rizzo <luigi@labinfo.iet.unipi.it> Cc: mike@smith.net.au (Mike Smith), freebsd-hackers@FreeBSD.ORG Subject: Re: PnP support Message-ID: <199709111002.UAA00256@word.smith.net.au> In-Reply-To: Your message of "Thu, 11 Sep 1997 11:13:45 %2B0200." <199709110913.LAA24117@labinfo.iet.unipi.it>
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> > [... strategy ...] > > The point I am making is that if you take this on, the parties > > responsible for these fields have already agreed on the course of > > action, and will be supporting you all the way. You won't have to > > worry about jurisdiction at all. > > ok. So a few more tech details. The resource management code should > then keep a private list of used resources, with functions like > haveseen_isa(), haveseen_pnp(), haveseen_pci() which check if any of > the requested resource is busy and return a success only if all are > free. Correspondingly there should be calls to make it possible to > register/unregister resource usage. Possibly we should also have > contigmalloc-like functions to return ranges of iospace etc within some > desired constraint (useful to allocate PnP address ranges etc.). This is why I exhorted you to look at the extent manager in NetBSD. It allows you to define "extents" which are just arbitrary ranges of "something". I would visualise this being used as follows : - the ISA startup code says "yup, this machine has an ISA bus", and creates an extent called "isa_io" and another called "isa_mem" - the ESCD or ISA startup code would create an extent called "isa_irq" and another called "isa_drq" indicating the resources available to the ISA bus. Traversal of these extents would then allow the PnP and vanilla-ISA probe/attach code to determine which regions were available for use and which had already been allocated. I don't think that making these extents "private" would be at all helpful. Having them public, and referenced by name, will make it easier to access them. > Due to recent events :) , but also to the start of classes and to > the need to keep developing the sound stuff, I don't have enough > time to also rewrite this resource allocation stuff which is a > necessary requirement to change the probe/attach sequence as > discussed in [strategy] above, so is there any volunteer ? I played a lot with the NetBSD extent allocator a while back. Jason didn't entirely like what I was doing (and TBH some of my ideas were pretty warped), but I would be happy to start over and just add the important bits (extent names & owners, public extents). I could probably have this ready in a few days. mike
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