Merge branch 'master' of git://www.denx.de/git/u-boot-ppc4xx

1 files changed, 21 insertions, 0 deletions

diff --git a/README b/README
index 5cbe7c1..3f36668 100644
--- a/README
+++ b/README
@@ -1929,6 +1929,27 @@ Configuration Settings:
 		Scratch address used by the alternate memory test
 		You only need to set this if address zero isn't writeable
 
+- CFG_MEM_TOP_HIDE (PPC only):
+		If CFG_MEM_TOP_HIDE is defined in the board config header,
+		this specified memory area will get subtracted from the top
+		(end) of ram and won't get "touched" at all by U-Boot. By
+		fixing up gd->ram_size the Linux kernel should gets passed
+		the now "corrected" memory size and won't touch it either.
+		This should work for arch/ppc and arch/powerpc. Only Linux
+		board ports in arch/powerpc with bootwrapper support that
+		recalculate the memory size from the SDRAM controller setup
+		will have to get fixed in Linux additionally.
+
+		This option can be used as a workaround for the 440EPx/GRx
+		CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
+		be touched.
+
+		WARNING: Please make sure that this value is a multiple of
+		the Linux page size (normally 4k). If this is not the case,
+		then the end address of the Linux memory will be located at a
+		non page size aligned address and this could cause major
+		problems.
+
 - CFG_TFTP_LOADADDR:
 		Default load address for network file downloads