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authorRafal Jaworowski <raj@pollux.denx.de>2006-03-16 17:46:46 +0100
committerRafal Jaworowski <raj@pollux.denx.de>2006-03-16 17:46:46 +0100
commitdc9e499c620a590e0f906e807e24c85807af3338 (patch)
tree035fb097d198f6208bfd90a628b6faf2fb9f22d3 /doc
parentd326f4a242971928ef5a6efb411a604b0478ef1c (diff)
Support for DDR with 32-data path. Addotional notes on injecting
multiple-bit errors.
Diffstat (limited to 'doc')
-rw-r--r--doc/README.mpc8349emds.ddrecc21
1 files changed, 21 insertions, 0 deletions
diff --git a/doc/README.mpc8349emds.ddrecc b/doc/README.mpc8349emds.ddrecc
index d8edada5654..401c0b687da 100644
--- a/doc/README.mpc8349emds.ddrecc
+++ b/doc/README.mpc8349emds.ddrecc
@@ -1,3 +1,24 @@
+Overview
+========
+
+The overall usage pattern for ECC diagnostic commands is the following:
+
+ * (injecting errors is initially disabled)
+
+ * define inject mask (which tells the DDR controller what type of errors
+ we'll be injecting: single/multiple bit etc.)
+
+ * enable injecting errors - from now on the controller injects errors as
+ indicated in the inject mask
+
+IMPORTANT NOTICE: enabling injecting multiple-bit errors is potentially
+dangerous as such errors are NOT corrected by the controller. Therefore caution
+should be taken when enabling the injection of multiple-bit errors: it is only
+safe when used on a carefully selected memory area and used under control of
+the 'ecc test' command (see example 'Injecting Multiple-Bit Errors' below). In
+particular, when you simply set the multiple-bit errors in inject mask and
+enable injection, U-Boot is very likely to hang quickly as the errors will be
+injected when it accesses its code, data etc.
Use cases for DDR 'ecc' command: