[U-Boot] [PATCH v3 17/19] da850: Add README.da850

[Tom Rini]

This file documents when to build for da850evm and when to build for
da850_am18xxevm.  It also documents how to write the u-boot.ais file to
persistent storage (such as SPI), in some cases as well as how to write
a recovery image.

Signed-off-by: Tom Rini <trini at ti.com>
---
Changes in v2:
- Add

Changes in v3:
- Fix thinko, Nand -> SPI (spotted by Prabhakar Lad)
- Rename to README.da850, add more direct recovery method (Christian Riesch)

 board/davinci/da8xxevm/README.da850 |   62 +++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 board/davinci/da8xxevm/README.da850

diff --git a/board/davinci/da8xxevm/README.da850 b/board/davinci/da8xxevm/README.da850
new file mode 100644
index 0000000..55291f3
--- /dev/null
+++ b/board/davinci/da8xxevm/README.da850
@@ -0,0 +1,62 @@
+Summary
+=======
+The README is for the boot procedure used for various DA850 (or compatible
+parts such as the AM1808) based boards.
+
+The board is booted in three stages. The initial bootloader which executes
+upon reset is the ROM Boot Loader (RBL) which sits in the internal ROM. The
+RBL initializes the memory and then depending on the exact board will
+initialize another controller (such as SPI or NAND) to continue the boot
+process.
+
+AIS is an image format defined by TI for the images that are to be
+loaded to memory by the RBL. The image is divided into a series of
+sections and the image's entry point is specified. Each section comes
+with meta data like the target address the section is to be copied to
+and the size of the section, which is used by the RBL to load the
+image. At the end of the image the RBL jumps to the image entry
+point.
+
+The secondary stage bootloader (SPL) which is loaded by the RBL then loads
+the u-boot from a predefined location in persistent storage to DDR and
+jumps to the u-boot entry point.
+
+
+Compilation
+===========
+The exact build target you need will depend on the board you have.  For
+Logic PD boards, or other boards which store the ethernet MAC address at
+the end of SPI flash, run 'make da850evm'.  For boards which store the
+ethernet MAC address in the i2c EEPROM located at 0x50, run
+'make da850_am18xxevm'.  Once this build completes you will have a
+u-boot.ais file that needs to be written to the correct persistent
+storage.
+
+
+Flashing the images to SPI
+==========================
+The AIS image can be written to SPI flash using the following commands.
+Assuming that the network is configured and enabled and the u-boot.ais file
+is tftp'able.
+
+U-Boot > sf probe 0
+U-Boot > sf erase 0 +320000
+U-Boot > tftp u-boot.ais
+U-Boot > sf write c0700000 0 $filesize
+
+
+Recovery
+========
+
+In the case of a "bricked" board, you need to use the TI tools found
+here[1] to write the u-boot.ais file.  An example of recovering to the SPI
+flash would be:
+
+$ mono sfh_OMAP-L138.exe -targetType AM1808 -p /dev/ttyUSB0 \
+	-flash_noubl /path/to/u-boot.ais
+
+
+Links
+=====
+[1]
+ http://processors.wiki.ti.com/index.php/Serial_Boot_and_Flash_Loading_Utility_for_OMAP-L137
-- 
1.7.9.5