The Egret system controller was the predecessor to the Cuda and the
differences are minor.
On Cuda, byte acknowledgement requires one transition of the TACK
signal; on Egret two are needed. On Cuda, TIP is active low; on Egret
it is active high. And Cuda raises certain interrupts that Egret omits.
Accomodating these differences complicates the Cuda driver slightly
but avoids a lot of duplication (see next patch).
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
d23eee88b5