[PATCH] PCI: xgene: Fix IB window setup

[dann frazier]

On Mon, Nov 29, 2021 at 11:36:37AM -0600, Rob Herring wrote:
> Commit 6dce5aa59e0b ("PCI: xgene: Use inbound resources for setup")
> broke PCI support on XGene. The cause is the IB resources are now sorted
> in address order instead of being in DT dma-ranges order. The result is
> which inbound registers are used for each region are swapped. I don't
> know the details about this h/w, but it appears that IB region 0
> registers can't handle a size greater than 4GB. In any case, limiting
> the size for region 0 is enough to get back to the original assignment
> of dma-ranges to regions.

hey Rob!

I've been seeing a panic on HP Moonshoot m400 cartridges (X-Gene1) -
only during network installs - that I also bisected down to commit
6dce5aa59e0b ("PCI: xgene: Use inbound resources for setup"). I was
hoping that this patch that fixed the issue on Stéphane's X-Gene2
system would also fix my issue, but no luck. In fact, it seems to just
makes it fail differently. Reverting both patches is required to get a
v5.17-rc kernel to boot.

I've collected the following logs - let me know if anything else would
be useful.

1) v5.17-rc2+ (unmodified):
   http://dannf.org/bugs/m400-no-reverts.log
   Note that the mlx4 driver fails initialization.

2) v5.17-rc2+, w/o the commit that fixed Stéphane's system:
   http://dannf.org/bugs/m400-xgene2-fix-reverted.log
   Note the mlx4 MSI-X timeout, and later panic.

3) v5.17-rc2+, w/ both commits reverted (works)
   http://dannf.org/bugs/m400-both-reverted.log

   -dann