On 11/06/2015 12:55 PM, Lorenzo Pieralisi wrote:
Hi Jeremy,
As I said, this is certainly confusing. AFAICT, I read "secondary bus"
as secondary bus side of the PCI bridge, I agree there is a mismatch
in the ACPI specs between the WordIo specification and the actual
Resource descriptors, reading page 366, for an IO resource descriptor,
_TTP:
Bit [4] I/O to Memory Translation, _TTP
1 TypeTranslation: This resource, which is I/O on the secondary
side of the bridge, is memory on the primary side
of the bridge.
0 TypeStatic: This resource, which is I/O on the secondary side of the
bridge, is also I/O on the primary side of the bridge.
Then (19.6.33):
That reads the other way around :), which one is correct ?
Well, I just read it for the two hundredth time today, and I'm back to
my original position this morning before posting that BS above, that
"secondary" refers to the device directed side, and primary is the
processor directed side.
For sure its made confusing by the link to the table 6-213, which says
basically the opposite of what is said in table 6-214. The difference
being that 6-214 is for IO regions (and what we are discussing, and the
link in the 6.0 docs is wrong, probably because both tables were on the
same page in 5.x).
So your probably right, and the juno is incorrect. That said, I suspect
we aren't the only ones, as i tested the juno against the RHEL release
which has PCI/ACPI in it (running against all the ARM64 servers, AFAIK),
and it was doing the right thing given the juno tables. <sigh> Which
back when I was doing them, initially I created the resource with the
base address=0, len=7FFFFF and the translate = 5f800000, but it didn't
work.
Can someone give us a dwordio example from an IA64 machine?
But, after reading it over and over, I still don't see how the _TTP bit
changes the way the translation is done... The TranslationDensity, yes,
but that is set to dense for the two examples so far. Its really in my
mind a question of whether the translate is added or subtracted, which
comes down to which direction primary and secondary refer to.
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