| 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-L138 |