[patch 1/1] powerpc: enable ARCH_DMA_ADDR_T_64BIT with ARCH_PHYS_ADDR_T_64BIT

[FUJITA Tomonori]

On Sat, 02 Oct 2010 13:20:54 +1000
Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:

> On Fri, 2010-10-01 at 21:31 -0400, Josh Boyer wrote:
> > > +config ARCH_DMA_ADDR_T_64BIT
> > > +       def_bool ARCH_PHYS_ADDR_T_64BIT
> > > +
> > 
> > I seemed to have missed what this is about entirely.  Is there some
> > place I can look that describes what that is supposed to do?  The PPC

This patchset unifies dma_addr_t typedef.

> > 4xx boards set PHYS_ADDR_T_64BIT because the MMU uses 36 bit
> > addressing, but the CPU is only 32 bits.  I want to make sure this DMA
> > thing isn't going to cause problems. 

this patchset changes nothing. Please see below.


> Yes, we need to test a bit. Our dma_addr_t has remained 32-bit so far
> because despite the fact that we've had routinely to deal with >32-bit
> physical addresses for MMIO, physical memory support has been
> constrained afaik to 32-bit.

Really?

The current dma_addr_t is:

#if defined(__powerpc64__) || defined(CONFIG_PHYS_64BIT)
typedef u64 dma_addr_t;
#else
typedef u32 dma_addr_t;
#endif
typedef u64 dma64_addr_t;


I think that this patch doesn't change anything. Or I miss something?

@@ -22,6 +22,9 @@ config WORD_SIZE
 config ARCH_PHYS_ADDR_T_64BIT
        def_bool PPC64 || PHYS_64BIT

+config ARCH_DMA_ADDR_T_64BIT
+       def_bool ARCH_PHYS_ADDR_T_64BIT
+
 config MMU
        bool
        default y