[FE training-materials-updates] Flash filesystem: instruct not to use the Device Tree

[Michael Opdenacker]

Repository : git://git.free-electrons.com/training-materials.git

On branch  : master
Link       : http://git.free-electrons.com/training-materials/commit/?id=a91aa9726f669e2a8b79db9ed58351274c28fbba

>---------------------------------------------------------------

commit a91aa9726f669e2a8b79db9ed58351274c28fbba
Author: Michael Opdenacker <michael.opdenacker at free-electrons.com>
Date:   Mon Nov 25 06:28:17 2013 +0100

    Flash filesystem: instruct not to use the Device Tree
    
    - Only the IGEP kernel without Device Tree
      properly works with JFFS2 images flashed from U-boot
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at free-electrons.com>


>---------------------------------------------------------------

a91aa9726f669e2a8b79db9ed58351274c28fbba
 .../sysdev-flash-filesystems.tex                   |   15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex b/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
index 34ea6de..5431f88 100644
--- a/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
+++ b/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
@@ -33,7 +33,20 @@ partitions specified in the kernel command line
 (\code{CONFIG_MTD_CMDLINE_PARTS}).
 
 Also enable support for the flash chips on the board
-(\code{CONFIG_MTD_NAND_OMAP2}).
+(\code{CONFIG_MTD_NAND_OMAP2}). You also need to enable support for
+hardware BCH error correction (\code{CONFIG_NAND_OMAP_BCH}) and select
+the \code{8 bits / 512 bytes (recommended)} mode
+(\code{MTD_NAND_OMAP_BCH8}).
+
+{\bf In this lab, you will also have to compile and boot a kernel without
+using the Device Tree. At least in Linux 3.11 and 3.12, there is an
+issue between the ECC mode declared in the IGEP Device Tree and the ECC
+configuration in U-boot 2013.10. The consequence is that JFFS2 images
+flashed from U-boot will cause ECC errors in Linux.}
+
+Therefore, compile your kernel with \code{CONFIG_MACH_IGEP0020} and
+boot your kernel without loading the Device Tree (\code{bootm
+800000000}).
 
 Last but not least, disable \code{CONFIG_PROVE_LOCKING}. This option is
 currently causing problems with the JFFS2 filesystem. This option is