Three changes to improve performance in the PDC driver: - disable and reenable interrupts while the interrupt handler is running - update rxin and txin descriptor indexes more efficiently - group receive descriptor context into a structure and keep context in a single array rather than five to improve locality of reference Signed-off-by: Rob Rice <rob.rice@broadcom.com> Reviewed-by: Andy Gospodarek <gospo@broadcom.com> Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>