Hi,

On Thu, 25 Jan 2001, Dan Malek wrote:

On the
embedded processors, all I/O is mapped through page tables, which
usually don't have 1:1 mapping.  The existing virt_to_phys and such
with just the arithmetic adjustment don't work on those.

And it doesn't really have to. virt_to_bus() might be a better place for
this. virt_to_phys() is at least on ia32 a quite speed sensitive function,
that only needs to work on normal low memory.

Some
systems have big holes in the physical space, including physical
addresses that map "under" the fixed kernel virtual addresses.

With holes do you mean several memory chunks? These should be handled with
memory zones.

I don't know what you mean by more "page oriented" as that is the
way it works now.  We just use BATs in some cases for efficiency, but
you don't have to.

I mean drivers get a pointer to a "struct page", what they can use to
get a virtual or physical address.

bye, Roman


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