Changeset 2367

Timestamp:

Jul 14, 2011 2:54:21 PM (23 months ago)

Author:

wmb

Message:

OLPC XO-1.75 - avoid EC command timeouts in the EC-SPI protocol by draining the FIFO if the EC has timed out and sent extra packets, acking only when the FIFO is empty.

File:

• dev/olpc/kb3700/spicmd.fth (modified) (4 diffs)

dev/olpc/kb3700/spicmd.fth

@@ -262 +262 @@
    pulse-ack
 ;
+: ?do-ack  ( -- )
+   \ If there is more data in the FIFO, it means that the EC
+   \ timed out and "inferred" an ACK, so we don't ACK until
+   \ the FIFO is empty.
+   ssp-ready? 0=  if  prime-fifo pulse-ack  then
+;
 : (upstream)  ( -- )
    ssp-ssdr rl@  ssp-ssdr rl@              ( channel# data )
@@ -268 +274 @@
    then
    over case                               ( channel# data )
-      0 of  2drop prime-fifo pulse-ack  endof  ( channel# data )  \ Invalid
+      0 of  2drop ?do-ack  endof           ( channel# data )  \ Invalid
       1 of  2drop handoff-command   endof  ( channel# data )  \ Switched
       ( default )                          ( channel# data channel# )
-         enque  prime-fifo pulse-ack       ( channel# )
+         enque  ?do-ack                    ( channel# )
    endcase
 ;
@@ -332 +338 @@
 ;
 
+: drain  ( -- )
+   begin  ssp-ready?  while  poll  repeat
+;
 : data-command  ( databuf datalen datain? cmdadr cmdlen more? -- )
    to sticky?  to cmdlen   to cmdbuf
@@ -339 +348 @@
    set-cmd-timeout
    ['] do-state behavior ['] upstream =  if
+      drain
       set-cmd
    else