PATCH 1/4][v4] doc:Add documentation for e500 external debugger support

This describes requirement of e500 and e500v2 processor to support external
debugger.

It also provide an insight of the configuration switch required and their
description.

Signed-off-by: Radu Lazarescu <radu.lazarescu@freescale.com>
Signed-off-by: Marius Grigoras <marius.grigoras@freescale.com>
Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
diff --git a/README b/README
index 67dc444..bb1b725 100644
--- a/README
+++ b/README
@@ -374,6 +374,15 @@
 		Defines the string to utilize when trying to match PCIe device
 		tree nodes for the given platform.
 
+		CONFIG_SYS_PPC_E500_DEBUG_TLB
+
+		Enables a temporary TLB entry to be used during boot to work
+		around limitations in e500v1 and e500v2 external debugger
+		support. This reduces the portions of the boot code where
+		breakpoints and single stepping do not work.  The value of this
+		symbol should be set to the TLB1 entry to be used for this
+		purpose.
+
 - Generic CPU options:
 		CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN