[FE training-materials-updates] U-boot lab: add details about physical addresses

Michael Opdenacker michael.opdenacker at free-electrons.com
Tue Dec 9 15:56:12 CET 2014

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

On branch  : master
Link       : http://git.free-electrons.com/training-materials/commit/?id=bd69508c51330827f497d87fdb60c6a99a914ffc


commit bd69508c51330827f497d87fdb60c6a99a914ffc
Author: Michael Opdenacker <michael.opdenacker at free-electrons.com>
Date:   Tue Dec 9 15:55:33 2014 +0100

    U-boot lab: add details about physical addresses
    Signed-off-by: Michael Opdenacker <michael.opdenacker at free-electrons.com>


 labs/sysdev-u-boot/sysdev-u-boot.tex | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/labs/sysdev-u-boot/sysdev-u-boot.tex b/labs/sysdev-u-boot/sysdev-u-boot.tex
index 84561cb..b38bf46 100644
--- a/labs/sysdev-u-boot/sysdev-u-boot.tex
+++ b/labs/sysdev-u-boot/sysdev-u-boot.tex
@@ -377,9 +377,22 @@ sudo service tftpd-hpa restart
 The \code{tftp} command should have downloaded
 the \code{textfile.txt} file from your development
-workstation into the board's memory at location \code{0x22000000} (this
-location is part of the board DRAM). You can verify that the download
-was successful by dumping the contents of the memory:
+workstation into the board's memory at location \code{0x22000000}
+\footnote{This location is part of the board DRAM. If you want
+to check where this value comes from, you can check the Atmel SAMA5D3
+datasheet at \url{http://www.atmel.com/tools/ATSAMA5D3-XPLD.aspx}, 
+following the {\em Documents} link. It's a big document (more than 1,800
+pages). In this document, look for \code{Memory Mapping} and you
+will find the SoC memory map. You will see that the address range for
+the the memory controller ({\em DDRC S}) starts at \code{0x20000000}
+and ends at \code{0x3fffffff}. This shows that the \code{0x22000000} 
+address is within the address range for RAM. You can also try with other
+values in the same address range, knowing that our board only has 256 MB
+of RAM (that's \code{0x10000000}, so the physical RAM probably ends at
+You can verify that the download was successful by dumping the
+contents of the memory:
 md 0x22000000

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