[PATCHES] ppc64 iommu rewrite & G5 support

[PATCHES] ppc64 iommu rewrite & G5 support

[Benjamin Herrenschmidt]

Hi !

In the following few emails are the bits of the long awaited ppc64
iommu rewrite and DART support for the PowerMac G5. The DART code
is still marked EXPERIMENTAL (though I haven't had any problem with
it here). 

I also implemented some basic virtual merging on top of the original
rewrite that is also marked EXPERIMENTAL and not enabled by default,
though it appears to work fine, because some drivers may still have
issues with it. It can still be enabled with a kernel command line
option despite beeing off in the .config (iommu=vmerge) or disabled
when the config .option is set (iommu=novmerge).

I will make it the default once we have moved the boundary limit
information down to struct device and fixed our pci_map_sg()
implementation to use that information, as it was discussed separately.

Many Kudos to Olof Johansson who did the bulk of the work, wiping out
the old ppc64 TCE mess to replace it with something that allowed people
like me to actually do further hacking on it while keeping the
noise/swearing level in the office acceptable (Rusty, in the cubicle
next to mine, will thank you Olof !) He is also responsible for getting
the crap out of Apple's DART implementation & HW bugs and producing a
working driver for it.

My contribution is limited to the vmerge stuff, further cleanups, some
fixes here or there, and proper IO hole accounting.

Have fun and backup your data !

Ben.