atl1: disable broken 64-bit DMA

atl1: disable broken 64-bit DMA

atl1: disable broken 64-bit DMA

[ Upstream commit: 5f08e46b621a769e52a9545a23ab1d5fb2aec1d4 ]

The L1 network chip can DMA to 64-bit addresses, but multiple descriptor
rings share a single register for the high 32 bits of their address, so
only a single, aligned, 4 GB physical address range can be used at a time.
As a result, we need to confine the driver to a 32-bit DMA mask, otherwise
we see occasional data corruption errors in systems containing 4 or more
gigabytes of RAM.

Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Jay Cliburn <jacliburn@bellsouth.net>
Acked-by: Chris Snook <csnook@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>