This package is a brand new UBL implementation for DM365.  The reason
for it is the need for SD boot, missing in the original package.

Unfortunately, the original package was too low quality to be worth
spending time on it. For example, it doesn't clear the BSS and so forth.
However, some source files come from there. I preserved attribution and
license (GNU GPL 2 like this whole package).

To compile set CROSS_COMPILE in your environment and then call make.
The binary (and all related files) is called bubl, "bubl.bin" is
ready to be programmed in SPI and "bubl" is an ELF file for debugging.

As should be known to the reader, this runs in TCM (tighly coupled memory),
which is ITCM ad address 0 and DTCM at address 0x10000 (64k).
Thus, memory placement should be like this:

instructions:
	0x0.0000: header for SPI
	0x0.0100: entry point (like original ubl, for easy transition)
	0x0.0200: real code start (after stack space). Up to 0x0.8000

data (overlapping):
	0x1.01fc: start of stack, going down (so we have 512b)
	0x1.8000: 32kB of buffer space.

Actually, there is not need to treat specially DTCM, so everything is
in the first 64kB.

What bubl does is initializing stuff (PLL and SDRAM, mainly) and setting
the stack pointer to RAM. Then it uses the sdcard (no HC support currently,
but the issue is detected) to load 256k of data and jump to it.

Such data is expected to be u-boot, starting from an offset of 4kB within
the flash. The initial offset allows a partition table to fit, so
part of the SD memory can be used for a real filesystem.

Data is loaded to address 0x81080000 which is where u-boot usually lives.
To copy u-boot to SD use something like this:

   dd bs=4k seek=1 if=u-boot.bin of=/dev/sdb

bubl is also able to load u-boot from a NAND device. It is assumed that there
are 4 copies of u-boot at 0x60000 offset one from other.