[commit] r3426 - cpu/arm/mmp2

[repository service]

Author: wmb
Date: Wed Nov 14 08:47:41 2012
New Revision: 3426
URL: http://tracker.coreboot.org/trac/openfirmware/changeset/3426

Log:
OLPC ARM MMP3 - turn off static branch prediction because it causes erratic results.

Modified:
   cpu/arm/mmp2/initmmu.fth

Modified: cpu/arm/mmp2/initmmu.fth
==============================================================================
--- cpu/arm/mmp2/initmmu.fth	Wed Nov 14 08:41:30 2012	(r3425)
+++ cpu/arm/mmp2/initmmu.fth	Wed Nov 14 08:47:41 2012	(r3426)
@@ -87,6 +87,16 @@

mcr  p15, 0, r0, cr7, cr5, 6        \ Flush branch target cache

+[ifdef] mmp3
+   \ This erratum is not listed in PJ4B-MP.ARMv7-ErrataRev-18.pdf
+   \ but we found this workaround in the qseven Linux kernel source.
+   \ It fixes a problem we were seeing with Python (trac #12164) so
+   \ I am including it in OFW just in case.
+   mcr  p15,1,r0,cr15,cr1,1            \ Workaround for PJ4B Errata 6409
+   bic  r0,r0,#0x04                    \ Disable static branch prediction
+   mrc  p15,1,r0,cr15,cr1,1
+[then]
+
    mrc p15,0,r0,cr1,cr0,0              \ Read control register
    orr r0,r0,#0x1000                   \ ICache on
    orr r0,r0,#0x0800                   \ Branch prediction on