If I got everything right, the bootrom is passing BOOT_DEVICE_UART as boot device, but you haven't selected CONFIG_SPL_YMODEM_SUPPORT. Thus, it falls back to asking omap_sys_boot_device, which is not implemented.
I don't think, there is everything right. Have a closer look to the #ifdef.
#if (defined(BOOT_DEVICE_UART) && !defined(CONFIG_SPL_YMODEM_SUPPORT)) || \ (defined(BOOT_DEVICE_USB) && !defined(CONFIG_SPL_USB_SUPPORT)) || \ (defined(BOOT_DEVICE_USBETH) && !defined(CONFIG_SPL_USBETH_SUPPORT))
I have enabled CONFIG_SPL_YMODEM_SUPPORT, look at bur_am335x_common.h.
The real problem here is that you have not enabled support for loading the main U-Boot binary via UART, with CONFIG_SPL_YMODEM_SUPPORT.
UART booting is unrelated to CONFIG_SPL_USBETH_SUPPORT.
No, due to the fact that defined(BOOT_DEVICE_USBETH) is allways true (spl.h) and i don't have CONFIG_SPL_USBETH_SUPPORT enabled, the #ifdef above:
defined(BOOT_DEVICE_USBETH) && !defined(CONFIG_SPL_USBETH_SUPPORT)
becomes true and the followed switch/case does the rest.
Oh you're right, I hadn't thought this through.
I'll think about how to solve this in the cleanest way (I wouldn't want to duplicate the ifdef logic too much). Thanks for bringing this up.
further i think that this construct isn't complete yet, because it wants to handle all peripheral booting on AM335x or OMAP in general.
following peripherals are currently handled:
BOOT_DEVICE_UART BOOT_DEVICE_USB BOOT_DEVICE_USBETH
but there is also BOOT_DEVICE_CPGMAC
Summary i think this changeset isn't complete.
Can the bootrom indicate that it booted from BOOT_DEVICE_CPGMAC? I haven't seen that and don't really know what it corresponds to. But if you think it is concerned by this fallback mechanism, you could add support for it. I only made this for the omap devices I have (and I don't have any am33xx board) and I didn't want to blindly implement too much for am33xx.
Yes, thats possible von AM335x. I will have a close look if it is necessary to implement here some fallback. But probably not, because the most likely case is that "full" U-Boot supports Ethernet and the SPL doesn't and not otherwise :-)
Alright then, that's fine with me. It's okay if the fallback mechanism doesn't handle all use cases, too.