One too many mornings

Having ported YAMON to scapa a while back, I’ve been adding tests into it to make it a useful bootstrapper for our purposes. At present it performs a Power-On Self Test or POST specific to scapa, and will retrieve a new kernel image if
it’s own own is missing or corrupt. It also configures it’s network params using dhcp, something YAMON did not do, I ported this from u-boot.

POST consists of

1. Turn off LED
2. Start Yamon from flash
3. Perform RAM data bus and address bus tests.
4. Perform a checksum on the YAMON code to test the flash bus.
5. Check the RTC
6. Set up MAC/PHY and wait for link
7. Perform stress test on RAM (caches enabled)
8. Probe PCI bus for emma and setup emma RAM, also bring tuners out of reset
9. Perform EMMA RAM data bus and address bus tests.
10. Probe i2c buses.
11. Get Mac Addr from the iButton
12. Get network params from flash
13. Check the kernel image.
14. If required do DHCP
15. If required tftp the kernel image to flash (see note below)
16. Copy kernel to RAM.
17. Jump to kernel

If at any time the user types ‘exit’ over the serial line, test code will exit and present a YAMON prompt.