Re: io resources and cached mappings (was: [git pull] drm patchesfor 2.6.27-rc1)

From: Arjan van de Ven
Date: Sun Oct 19 2008 - 14:01:21 EST

On Sun, 19 Oct 2008 19:53:20 +0200
Ingo Molnar <mingo@xxxxxxx> wrote:

> struct resource {
> resource_size_t start;
> resource_size_t end;
> const char *name;
> unsigned long flags;
> struct resource *parent, *sibling, *child;
> + void *mapping;
> };
> The APIs would be:
> int io_resource_init_mapping(struct resource *res);
> void io_resource_free_mapping(struct resource *res);
> void * io_resource_map(struct resource *res, pfn_t pfn, unsigned
> long offset); void io_resource_unmap(struct resource *res, void
> *kaddr);
> Note how simple and consistent it all gets: IO resources already know
> their physical location and their size limits. Being able to cache an
> ioremap in a mapping [and being able to use atomic kmaps on 32-bit]
> is a relatively simple and natural extension to the concept.

and making a simple wrapper around this that turns "struct pci_dev,
barnr" into a resource would make sense too, but yes.

We need one more

io_resource_force_cachability(struct resource, cachetype)

or maybe only

io_resource_force_writecombine(struct resource)

Arjan van de Ven Intel Open Source Technology Centre
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