How to support 3GB pci address?

[Trent Piepho]

On Thu, 11 Dec 2008, Kumar Gala wrote:
> On Dec 11, 2008, at 6:04 AM, maillist.kernel wrote:
>> In the system, the total PCI address needed is about 3GB, so I want to know 
>> how to support it in linux. mpc8548 has 36-bit real address, and can 
>> support 32GB PCIE address space, but in linux, there is only 1GB kernel 
>> space, how to map the 3GB pci address to kernel? Is the  36-bit real 
>> address only used to support large memory(>4GB) for muti-threads?
>
> The 36-bit support is current (in tree) in complete.  Work is in progress to 
> add swiotlb support to PPC which will generically enable what you want to 
> accomplish.

Don't the ATMU windows in the pcie controller serve as a IOMMU, making swiotlb
unnecessary and wasteful?