[U-Boot] [PATCH v5 20/25] da850: Add README.da850

[Tom Rini <trini@ti.com>]

On 08/28/2012 12:27 AM, Christian Riesch wrote:
> Hi Tom,
> one more comment, please see below.
> 
> On Tue, Aug 28, 2012 at 1:18 AM, Tom Rini <trini@ti.com> wrote:
>> 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@ti.com>
>> ---
>> Changes in v2:
>> - Add README.da850_am18xxevm
>>
>> Changes in v3:
>> - Fix thinko, Nand -> SPI (spotted by Prabhakar Lad)
>> - Rename to README.da850, add more direct recovery method (Christian Riesch)
>>
>> Changes in v4:
>> - Further re-word README.da850 based on feedback from Christian Riesch
>>
>>  board/davinci/da8xxevm/README.da850 |   68 +++++++++++++++++++++++++++++++++++
>>  1 file changed, 68 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..621a95d
>> --- /dev/null
>> +++ b/board/davinci/da8xxevm/README.da850
>> @@ -0,0 +1,68 @@
>> +Summary
>> +=======
>> +The README is for the boot procedure used for various DA850 (or compatible
>> +parts such as the AM1808) based boards.
>> +
>> +In the context of U-Boot, the board is booted in three stages. The initial
>> +bootloader which executes upon reset is the ROM Boot Loader (RBL) and sits
>> +in the internal ROM. The RBL initializes the internal memory and then
>> +depending on the exact board and pin configurations will initialize another
>> +controller (such as SPI or NAND) to continue the boot process by loading
>> +the secondary program loader (SPL).  The SPL will initialize the system
>> +further (some clocks, SDRAM) and then load the full u-boot from a
>> +predefined location in persistent storage to DDR and jumps to the u-boot
>> +entry point.
>> +
>> +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 AIS format allows for
>> +other things such as programming the clocks and SDRAM if the header is
>> +programmed for it.  We do not take advantage of this and instead use SPL as
>> +it allows for additional flexibility (run-time detect of board revision,
>> +loading the next image from a different media, etc).
>> +
>> +
>> +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 $filesize
>> +
>> +
>> +Recovery
>> +========
>> +
>> +In the case of a "bricked" board, you need to use the TI tools found
>> +here[1] to write the u-boot.ais file.  An example of recovering to the SPI
>> +flash of an AM1808 would be:
>> +
>> +$ mono sfh_OMAP-L138.exe -targetType AM1808 -p /dev/ttyUSB0 \
>> +       -flash_noubl /path/to/u-boot.ais
>> +
>> +For other target types and flash locations:
>> +
>> +$ mono sfh_OMAP-L138.exe -h
>> +
>> +Links
>> +=====
>> +[1]
>> + http://processors.wiki.ti.com/index.php/Serial_Boot_and_Flash_Loading_Utility_for_OMAP-L137
> 
> I'm not sure if the flash loader for the L137 would work for the L138
> and the AM1808 as well, please use this URL instead:
> http://processors.wiki.ti.com/index.php/Serial_Boot_and_Flash_Loading_Utility_for_OMAP-L138
> 
> Sorry, I didn't notice that in earlier versions...

Whoops, fixed, ack added, thanks!

-- 
Tom