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authorWolfgang Denk <wd@nyx.denx.de>2006-03-06 11:25:22 +0100
committerWolfgang Denk <wd@nyx.denx.de>2006-03-06 11:25:22 +0100
commit4e3ccd26925e5ada78dd89779838f052dffe3e67 (patch)
tree2df070a78b8f9e69b03b0e0b8bfd01d0d639865e /doc/README.nand
parentf1ee982506d8e58262ff0e5d1fb208e703640e34 (diff)
parentaddb2e1650fdf872334478393f482dfdce965a61 (diff)
Merge the new NAND code (testing-NAND brach); see doc/README.nand
Rewrite of NAND code based on what is in 2.6.12 Linux kernel Patch by Ladislav Michl, 29 Jun 2005 [Merge with /home/tur/nand/u-boot]
Diffstat (limited to 'doc/README.nand')
-rw-r--r--doc/README.nand35
1 files changed, 35 insertions, 0 deletions
diff --git a/doc/README.nand b/doc/README.nand
index 0f2bdc5cc4..cd7608cf7f 100644
--- a/doc/README.nand
+++ b/doc/README.nand
@@ -1,5 +1,9 @@
NAND FLASH commands and notes
+
+See NOTE below!!!
+
+
# (C) Copyright 2003
# Dave Ellis, SIXNET, dge@sixnetio.com
#
@@ -173,3 +177,34 @@ More Definitions:
#define NAND_ChipID_UNKNOWN 0x00
#define NAND_MAX_FLOORS 1
#define NAND_MAX_CHIPS 1
+
+
+
+NOTE:
+=====
+
+We now use a complete rewrite of the NAND code based on what is in
+2.6.12 Linux kernel.
+
+The old NAND handling code has been re-factored and is now confined
+to only board-specific files and - unfortunately - to the DoC code
+(see below). A new configuration variable has been introduced:
+CFG_NAND_LEGACY, which has to be defined in the board config file if
+that board uses legacy code. If CFG_NAND_LEGACY is defined, the board
+specific config.mk file should also have "BOARDLIBS =
+drivers/nand_legacy/libnand_legacy.a". For boards using the new NAND
+approach (PPChameleon and netstar at the moment) no variable is
+necessary, but the config.mk should have "BOARDLIBS =
+drivers/nand/libnand.a".
+
+The necessary changes have been made to all affected boards, and no
+build breakage has been introduced, except for NETTA and NETTA_ISDN
+targets from MAKEALL. This is due to the fact that these two boards
+use JFFS, which has been adopted to use the new NAND, and at the same
+time use NAND in legacy mode. The breakage will disappear when the
+board-specific code is changed to the new NAND.
+
+As mentioned above, the legacy code is still used by the DoC subsystem.
+The consequence of this is that the legacy NAND can't be removed from
+the tree until the DoC is ported to use the new NAND support (or boards
+with DoC will break).