GDMA

This device is not officially documented, but there are enough clues available to detect its presence.

Based on the name, it seems to be a DMA engine. Quite possibly it's broken and was disabled for that reason.

device	MMIO	IRQ	reset	description
GDMA	0xb0004000	?	3	DMA engine

Registers

When the register window is filled with an 0xff pattern, it looks like this:

b0004000: 030bbbfd ffffffff ffffffff 00ffffff 00000000 00000000 00000000 00000000
b0004020: 030bbbfd ffffffff ffffffff 00ffffff 00000000 00000000 00000000 00000000
b0004040: 030bbbfd ffffffff ffffffff 00ffffff 00000000 00000000 00000000 00000000
b0004060: 030bbbfd ffffffff ffffffff 00ffffff 00000000 00000000 00000000 00000000

Further experimentation shows that there are two instances (at +0x00 and +0x20), which repeat until 0xb0004fff.

offset	type	description
0	u32	command register (?)
4	u32	source or destination (?)
8	u32	source or destination (?)
12	u32	transfer length (?)

Command register

Bits that stick:  0x030bbbfd = 00000011'00001011'10111011'11111101