Subject: Re: Proposed extension to bus.h interface
To: Jason Thorpe <>
From: Chris G Demetriou <>
List: tech-kern
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.