Dear Marcel,
In message 201009270011.32850.korgull@home.nl you wrote:
I do however have some questions about the u-boot startup behaviour.
Please read the manual; it should cover most of your questions.
What I want to create is the following :
- u-boot starts and checks if it can start my application (either CRC check
or whatever). This is the first thing u-boot should do. 2) if it can't boot it will listen on USB or ethernet for someone to upload a valid image or boot via NFS or whatever has been configured.
This is standard behaviour. See 7.4. Boot Arguments Unleashed etc., http://www.denx.de/wiki/view/DULG/LinuxBootArgs
- If it can boot, it will boot immediately (there may be a GPIO pin to
override this behaviour)
setenv bootdelay 0
- once within the application (linux or whatever) I must be able to set a flag
that lets u-boot wait for uploading a new image file when I soft-reset my device. This is needed for firmware upgrading of course. I still need to check if this flag is supported by the CPU or needs other support (eeprom perhaps).
see tools/env for tools to read and write the U-Boot environment settings from Linux. This can be used to change the boot command, boot delay etc.
- After uploading an image the soft-reset is cleared and the whole sequence
start over again, so it should boot the new image.
You can script all these things in U-Boot.
I know it's possible to do this but I wonder if it has been done before and if there any examples of it ?
There is all kinds of more or less complext stuff around. Read the manual. Read the default configurations set in other board config files. Read the code available in board/*/auto_update.c etc.
Best regards,
Wolfgang Denk