Hardware/SATA controller

The Wii U has a mostly standard AHCI 1.2 SATA controller onboard. It identifies as having two ports (0 and 1) capable of 3Gbps. In retail systems, the disc drive is connected to port 0; while port 1 is disconnected.

SATA controller
Access
Espresso	None
Starbuck	Full
Registers
Base	0x0d160000
Length	0x808
Access size	32 bits
Byte order	Big Endian
Latte	6 (LT), 28 (ALL)

In terms of hardware registers; the controller lines up with the specification starting at address 0x0D160400; that is; the first Generic Host Control register (Host Capabilities) resides at 0x0D160400. On a retail console, this register reads out 0x7720FF81. The controller is not entirely standard, however - only 6 ports worth of MMIO space has been allocated, after which a custom set of interrupt control registers exist.

Interrupts

The Wii U's SATA controller uses custom interrupt routing "in front" of the standard AHCI mechanism. The IOSU masks and acknowledges IRQs in both the custom registers and the standard ones - it appears an IRQ must be enabled in both the AHCI registers and the custom IRQ controller for it to be delivered to the Latte IRQ Controller (LT #6).

IRQ	Description
0	Unknown (disc inserted?)
1	Unknown
3	AHCI Port 0 IRQ
5	AHCI Port 1 IRQ

The SATA controller also owns Latte IRQ ALL #28. It's unknown what this is used for, but an IOSU debug string suggests it can deliver spurious "DBGINT"s in some situations.

Registers

• The generic host control registers start at 0x0D160400.
• The port registers start at 0x0D160500.
• The port registers *finish* at 0x0D160800, while the AHCI spec requires them to end at 0x0D161100.

SATA_HCCFG_INT_REG (0x0d160800)
	310
Access	R/W

This register contains the IRQ flag bits. These are set by the hardware. To clear a flag, write 1 to it.

SATA_HCCFG_INTMSK_REG (0x0d160804)
	310
Access	R/W

This register contains the IRQ mask bits. If a bit is set, then the corresponding flag bit will cause Latte IRQ LT #7 to be asserted.

ATAPI commands

Besides commands defined in the ATAPI specification, the Wii U also seems to have some custom commands.

0xF5 - ATAPI_CF_INQUIRY_CMD

Offset	Size	Description
0x00	0x02	Unknown
0x02	0x01	Vendor
0x03	0x01	Device
0x04	0x1C	Unknown
0x20	-	End

See Also

AHCI 1.2 spec