[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>
>---------------------------------------------------------------
bd69508c51330827f497d87fdb60c6a99a914ffc
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
+\code{0x30000000}).}.
+
+You can verify that the download was successful by dumping the
+contents of the memory:
\begin{verbatim}
md 0x22000000
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