[openfirmware] [commit] r3426 - cpu/arm/mmp2
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Wed Nov 14 08:47:43 CET 2012
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
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