I have a Virtex4 VF60 device with 256MB DDR2.
I have told the Linux kernel that the device has only 128MB and its
working fine. There is an HDL module that is populating the next 16MB
with sensor data (0x08000000 - 0x09000000) I mapped the area into my
driver via `ioremap()` and also via `mmap / remap_pfn_range()` It
works fine.
I know that PPC cache regions work in 128MB blocks. I assume that the
kernel bootup is turning on cache in the first 128, because it thinks
that its the full RAM range, and not cached in the next 128MB.
I know that if I declare the area cached, and invalidate the region
before I read it, the reads should be much faster than if it's not
cached.
How can I control if the area is cached? and then invalidate it when
new data arrives?
Is there a PPC/Linux API call to declare the region cached and
invalidate regions before read?
Rob.
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