[U-Boot] [PATCH v2 16/18] da850_am18xxevm: Add README.da850_am18xxevm

[Prabhakar Lad]

Hi Tom,

Thanks for the patch.

On Monday 20 August 2012 10:15 PM, Tom Rini wrote:
> Add a board-specific README that documents how to write u-boot.ais to
> the SPI found on this board.
> 
> Changes-series: 2
> - Add
> 
> Signed-off-by: Tom Rini <trini at ti.com>
> ---
> 
>  board/davinci/da8xxevm/README.da850_am18xxevm |   53 +++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
>  create mode 100644 board/davinci/da8xxevm/README.da850_am18xxevm
> 
> diff --git a/board/davinci/da8xxevm/README.da850_am18xxevm b/board/davinci/da8xxevm/README.da850_am18xxevm
> new file mode 100644
> index 0000000..382b718
> --- /dev/null
> +++ b/board/davinci/da8xxevm/README.da850_am18xxevm
> @@ -0,0 +1,53 @@
> +Summary
> +=======
> +The README is for the boot procedure used for the LogicPD AM1808 EVM.
> +
> +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 initialises the memory and the SPI controller and reads the AIS image
> +starting at block 0.  This image can contain both the SPL and U-Boot
> +binaries.
> +
> +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 SPI to DDR and jumps to the u-boot
> +entry point.
> +
> +
> +Compilation
> +===========
> +To build a SPI-bootable image, run 'make da850_am18xxevm'.  This will build
> +the u-boot.ais file that needs to be written to SPI flash.
> +
> +
> +Flashing the images to Nand
> +===========================
> +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
> +
  Is this procedure to be done in Nand boot mode ?

Thx,
--Prabhakar

> +
> +Recovery
> +========
> +
> +In the case of a "bricked" board, you need to use the TI tools found
> +here[1] to write a UBL file and u-boot.bin.  Once the system is running
> +again from these tools a good u-boot.ais may be re-written to SPI flash.
> +
> +
> +Links
> +=====
> +[1]
> + http://processors.wiki.ti.com/index.php/Serial_Boot_and_Flash_Loading_Utility_for_OMAP-L137
>