Hi All,
Has anyone come across to the need to run the standalone application in SPL? Due to the onchip SRAM size limitation in our chip, we will need run the small foot print SPL to initialization DDR before we load the u-boot proper to the main DDR memory. We will have to run our DDR initialization in standalone application binary mode due to some restriction of library. I posted a separate thread here https://lists.denx.de/pipermail/u-boot/2019-August/379585.html. Understand SPL does not have a shell to load the application interactively but one can load the binary from flash and jump to its entry point when it is needed during the boot of SPL.
I looked through u-boot code and it is fairly straightforward to enable standalone application in SPL. All it takes are adding configure option in spl/Kconfig, makefile changes to include export.c and examples folder and jumptable init in the spl init time.
I do need to ifdef the do_reset as dummy for SPL in the _export.h due to the fact that do_reset function is not available in SPL without enabling a lot of supporting code. It looks to me add ifdef is the simplest way to go and does not break any other build.
#if !defined(CONFIG_SPL_STANDALONE)
EXPORT_FUNC(do_reset, int, do_reset, cmd_tbl_t *,
int , int , char * const [])
#else
EXPORT_FUNC(dummy, void, do_reset, void)
#endif
Any feedback and comments are appreciated! I can post a patch for review and contribute to u-boot if this sounds a good add-on for SPL.
Thanks,
William