On Dec 11, 2008, at 10:07 PM, Trent Piepho wrote:
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?
Nope. You have no way to tell when to switch a window as you have no
idea when a device might DMA data.
- k
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