[openfirmware] [commit] r3157 - cpu/arm/olpc

[repository service]

Author: rsmith
Date: Mon Aug 13 21:42:03 2012
New Revision: 3157
URL: http://tracker.coreboot.org/trac/openfirmware/changeset/3157

Log:
OLPC CL4 - Fix EC flash fail after cold boot

After a cold boot the first attempt to flash the EC would fail with a
"EC byte in confused" then all attempts after that would fail with a
"Bad SPI FLASH ID 0" until you did a warm boot then they would
succeed.

The EDI interface requires a EDI transaction with a clock between 1
and 8 Mhz for it to enable.  Empirically we see that the data you get
back from this 1st transaction are zeros and so the 1st read will
abort because zero is not a valid response an EDI transaction.  The
previous did a catch and retry when it ran the select-flash operation
but with the introduction of the io3790 a chip ID check has to be run
first.
The ID command does not be sufficient to enable the EDI interface
(also found empirically) it appears to have to be a read.

So now when we do the dummy read we ignore it if it fails rather than
abort out.

This also fixed the "Bat SPI FLASH ID 0" problem so it would seem that
if edi-open takes an abort that things are not properly cleaned up or
correctly re-initialized on the next attempt.  I didn't debug the problem any
further.

Modified:
   cpu/arm/olpc/edi.fth

Modified: cpu/arm/olpc/edi.fth
==============================================================================
--- cpu/arm/olpc/edi.fth	Mon Aug 13 09:10:50 2012	(r3156)
+++ cpu/arm/olpc/edi.fth	Mon Aug 13 21:42:03 2012	(r3157)
@@ -72,7 +72,9 @@
             unloop exit
          then             ( d )
          spi-cs-off       ( d )
-         h# ff =  abort" EDI byte in inactive"
+	 \ The setup in the CL4 has can also report zeros when inactive.
+         2dup h# ff = 00 = or abort" EDI byte in inactive"
+	 ." Unknown EDI byte in response: " .h cr
          true abort" EDI byte in confused"
       then                ( d )
       drop
@@ -336,8 +338,8 @@
    \ slow-edi-clock   \ Target speed between 1 and 2 MHz
    spi-start
 
-   \ dummy read, to activate EDI
-   h# ff22 edi-b@ drop
+   \ dummy read, to activate EDI and can fail so ignore the fail
+   h# ff22 ['] edi-b@ catch if noop else drop then
    
    set-chip-id