[RFC] POWERPC: Merge 32 and 64-bit dma code

[Mark Nelson]

On Fri, 23 May 2008 06:06:50 pm Mark Nelson wrote:
> On Thu, 1 May 2008 09:36:43 am Becky Bruce wrote:
> > 
> > I essentially adopt the 64-bit dma code, with some changes to support
> > 32-bit systems, including HIGHMEM.  dma functions on 32-bit are now
> > invoked via accessor functions which call the correct op for a device based
> > on archdata dma_ops.  Currently, this defaults to dma_direct_ops, but this
> > structure will make it easier to do iommu/swiotlb on 32-bit going
> > forward.
> > 
> > In addition, the dma_map/unmap_page functions are added to dma_ops on
> > HIGHMEM-enabled configs because we can't just fall back on map/unmap_single
> > when HIGHMEM is enabled.  Adding these to dma_ops makes it cleaner to
> > substitute different functionality once we have iommu/swiotlb support.
> > 
> > This code conflicts with the dma_attrs code that Mark Nelson just pushed.
> > At this point, I'm just looking for some review, and suggestions on how 
> > this code might be improved.  I'll uprev it to work with Mark's code once
> > that goes in.
> 
> The last patch of my series may be in question so it could end up that this
> patch makes it in first. It shouldn't be too hard to respin my patches after
> your merge so no worries there though.
> 
> > 
> > There will be other patches that precede this one - I plan to duplicate 
> > dma_mapping.h into include/asm-ppc to avoid breakage there.  There will 
> > also be a patch to rename dma_64.c to dma.c, and a series of patches to 
> > modify drivers that pass NULL dev pointers.
> > 
> > Dma experts, please review this when you can - I was a dma newbie 
> > until very recently, and the odds that I'm missing some subtlety 
> > in this merge are fairly high.
> > 
> 
> I'm far from a DMA expert but this all looks sane to me - I can't really
> comment on the 32bit side of things but I don't think it's going to break
> anything on 64bit (it compiles fine on cell and pseries).
> 
> I'll try and test boot it on Monday.

Not quite Monday, but it boots fine on the QS22 and QS21 Cell blades
and on a Power6 box.

Mark.

> 
> We should get BenH to look at it but he's travelling at the moment...
> 
> Mark.
> 
> > Cheers,
> > Becky
> > 
> >  ---
> >  arch/powerpc/kernel/Makefile      |    4 +-
> >  arch/powerpc/kernel/dma_64.c      |   80 ++++++++++++++++++-
> >  arch/powerpc/kernel/pci-common.c  |   53 +++++++++++++
> >  arch/powerpc/kernel/pci_32.c      |    7 ++
> >  arch/powerpc/kernel/pci_64.c      |   49 ------------
> >  include/asm-powerpc/dma-mapping.h |  156 +++++++++----------------------------
> >  include/asm-powerpc/machdep.h     |    5 +-
> >  include/asm-powerpc/pci.h         |   14 ++--
> >  8 files changed, 186 insertions(+), 182 deletions(-)
> <snip>