Hi,
Thanks a lot to all of you for the help . 
The following is a more clearer version of the problem I am facing :

1.I am porting drivers from X86 (running Linux 2.4-20) to 
  PPC platform running (Montevista Linux-2.4.20).
2.In  wrapper function for DMA allocation, I am using 
  consistent_alloc() to allocate the memory. This function gives me
  both the virtual-address as well as the dma-address.
  I pass both these values to the upper-level drivers.
3. However , once the upper-level drivers are done with the memory
   they call the wrapper function for free dma and pass only the dma
   address and not the virtual-address. However consistent_free() 
   accepts only virtual-address. 
   Hence I need a way to convert the dma address to the
   virtual-address.  

Regards
sachin


On Wed, 19 Jan 2005 07:56:03 -0700, Matt Porter
[off-list ref] wrote:

On Wed, Jan 19, 2005 at 03:10:48PM +0100, Christoph Hellwig wrote:

quoted

On Wed, Jan 19, 2005 at 05:23:17PM +0530, Sachin P wrote:

quoted

Hi ,
I am facing some problems porting my drivers to the PPC platform . Am
currently using consistent_alloc() and consistent_free() to
allocate/free (non-cached) DMA ble memory.
Is there any function/patch/macro, equivalent to
phy_to_virt()/virt_to_phy() for memory returned by consistent_alloc()?

Don't ever use concistant_alloc directly.  Always use
dma_alloc_coherent() which will give you both virtual and bus address.

He's obviously not talking about 2.6 since he's mentioning
consistent_alloc().  I removed those PPC-specific APIs when I
updated our DMA API implementation in 2.6.

-Matt