Re: Discussion about iopa()

On Feb 9, 2007, at 4:06 PM, Benjamin Herrenschmidt wrote:

On Fri, 2007-02-09 at 12:13 -0500, Dan Malek wrote:

quoted

On Feb 8, 2007, at 4:26 PM, Benjamin Herrenschmidt wrote:

quoted

I'm really not fan of it.

That's because I think it's a terribly useful function
and the first step toward some orthogonal VM APIs. :-)

No, I think it's very inefficient to walk the page tables, even  
worse if
you have PTEs in HIGHMEM. I think it's better to keep track the  
physical
address from alloc time, something similar than dma_alloc_coherent but
for use with that MURAM thingy.

My feeling is to leave the code alone until we have the dma mapping  
api setup to handle MURAM.  If we can't do alloc/map/free with the  
same mechanism I dont see the value in just doing 'map'.  It just  
makes the code more confusing w/o any big gain.

Truthfully the normal system memory size should be cleaned up to use  
the dma mapping API instead of straight allocations and mapping like  
its using now.

- k