tree f9dd88a6a64d74f93512fb65a30a761c7a5be645
parent a05e576f7fd883be1a405e7acac136eef1d601e0
author Alexandru Elisei <alexandru.elisei@arm.com> 1589470702 +0100
committer Will Deacon <will@kernel.org> 1589906281 +0100

pci: Limit configuration transaction size to 32 bits

>From PCI Local Bus Specification Revision 3.0. section 3.8 "64-Bit Bus
Extension":

"The bandwidth requirements for I/O and configuration transactions cannot
justify the added complexity, and, therefore, only memory transactions
support 64-bit data transfers".

Further down, the spec also describes the possible responses of a target
which has been requested to do a 64-bit transaction. Limit the transaction
to the lower 32 bits, to match the second accepted behaviour.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/1589470709-4104-6-git-send-email-alexandru.elisei@arm.com
Signed-off-by: Will Deacon <will@kernel.org>