tree 3e8387932c5cc10facffa248ecfb648564a9ae5e
parent d4fabcc8e8ecac21262b1a5b9684fe415b128bd2
author Neil Turton <nturton@solarflare.com> 1302518563 +0100
committer Ben Hutchings <bhutchings@solarflare.com> 1302648764 +0100

sfc: Use rmb() to ensure reads occur in order

Enabling write-combining may also enable read reordering.  The BIU is
only guaranteed to read from a 128-bit CSR or 64-bit SRAM word when
the host reads from its lowest address; otherwise the BIU may use the
latched value.  Therefore we need to reinstate the read memory
barriers after the first read operation for each CSR or SRAM word.

Signed-off-by; Ben Hutchings <bhutchings@solarflare.com>