Subject: Re: Proposed extension to bus.h interface
To: Jason Thorpe <firstname.lastname@example.org>
From: Chris G Demetriou <Chris_G_Demetriou@ux2.sp.cs.cmu.edu>
Date: 08/15/1996 16:47:09
> I would like to propose the addition of the following 4 functions to the
> bus.h interface:
> int bus_mem_alloc(t, size, alignment, cacheable, bpap, mhp)
> bus_chipset_tag_t t;
> bus_mem_size_t size, alignment;
> int cacheable;
> bus_mem_addr_t *bpap;
> bus_mem_handle_t *mhp;
> Allocate bus physical address space of size `size' with alignment
> `alignment'. If no alignment is required, the caller will pass
> the placeholder BUS_MEM_NOALIGN for the `alignment' argument.
> [ ... ]
Why use BUS_MEM_NOALIGN? "1" is the logically correct value to use.
I could imagine that you might need a "don't return a region that
crosses the following boundary," i.e. the same thing that the
'boundary' argument to extent_alloc_subregion does.