forked from Minki/linux
a83f982313
There is an implicit assumption in the code that ranges will translate
to something that can fit in 2 32-bit cells, or a 64-bit value. For
certain kinds of things below PCI this isn't necessarily true.
Here is what the relevant OF device hierarchy looks like for one of
the serial controllers on an Ultra5:
Node 0xf005f1e0
ranges: 00000000.00000000.00000000.000001fe.01000000.00000000.01000000
01000000.00000000.00000000.000001fe.02000000.00000000.01000000
02000000.00000000.00000000.000001ff.00000000.00000001.00000000
03000000.00000000.00000000.000001ff.00000000.00000001.00000000
device_type: 'pci'
model: 'SUNW,sabre'
Node 0xf005f9d4
device_type: 'pci'
model: 'SUNW,simba'
Node 0xf0060d24
ranges: 00000010.00000000 82010810.00000000.f0000000 01000000
00000014.00000000 82010814.00000000.f1000000 00800000
name: 'ebus'
Node 0xf0062dac
reg: 00000014.003083f8.00000008 --> 0x1ff.f13083f8
device_type: 'serial'
name: 'su'
So the correct translation here is:
1) Match "su" register to second ranges entry of 'ebus', which translates
into a PCI triplet "82010814.00000000.f1000000" of size 00800000, which
gives us "82010814.00000000.f13083f8".
2) Pass-through "SUNW,simba" since it lacks ranges property
3) Match "82010814.00000000.f13083f8" to third ranges property of PCI
controller node 'SUNW,sabre', and we arrive at the final physical
MMIO address of "0x1fff13083f8".
Due to the 2-cell assumption, we couldn't translate to a PCI 3-cell
value, and we couldn't perform a pass-thru on it either.
It was easiest to just stop splitting the ranges application operation
between two methods, ->map and ->translate, and just let ->map do all
the work. That way it would work purely on 32-bit cell arrays instead
of having to "return" some value like a u64.
It's still not %100 correct because the out-of-range check is still
done using the 64 least significant bits of the range and address.
But it does work for all the cases I've thrown at it so far.
Signed-off-by: David S. Miller <davem@davemloft.net>
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