DMA Setup FIS – Device to Host or Host to Device (Bidirectional) - FIS Type (41h)

DMA Setup – Device to Host or Host to Device (Bidirectional) FIS:

		31		30	29	28	27	26	25	24		23	22	21	20	19	18	17	16	15	14		13		12		11	10	9	8	7	6	5	4	3	2	1	0
	0		Reserved								Reserved									A		I		D		R	PM Port				FIS Type (41h)
	1		DMA Buffer Identifier Low
	2		DMA Buffer Identifier High
	3		Reserved
	4		DMA Buffer Offset
	5		DMA Transfer Count
	6		Reserved

FIS Type - Set to a value of 41h. Defines the rest of the FIS fields. Defines the total length of the FIS as seven Dwords.

D Direction - Specifies whether subsequent data transferred after this FIS is from transmitter to receiver or from receiver to transmitter If set to one the direction is transmitter to receiver.If cleared to zero, the direction is receiver to transmitter.

A Auto-Activate - If set to one, in response to a DMA Setup FIS with data transfer direction of Host-to-Device, causes the host to initiate transfer of the first Data FIS to the device after the DMA context for the transfer has been established. The device shall not transmit a DMA Activate FIS to trigger the transmission of the first Data FIS from the host. If cleared to zero, a DMA Activate FIS is required to trigger the transmission of the first Data FIS from the host when the data transfer direction is Host-to-Device.

DMA Buffer Identifier Low/High - This field is used to identify a DMA buffer region in host memory. The contents are not described in this specification and are host dependent. The buffer identifier is supplied by the host to the device and the device echoes it back to the host. This allows the implementation to pass a physical address or or, in more complex implementations, the buffer identifier could be a scatter gather list or other information that may identify a DMA channel”.

DMA Buffer Offset - This is the byte offset into the buffer. Bits [1:0] shall be zero.

DMA Transfer Count - This is the number of bytes to be read or written. Bit zero shall be zero.

I Interrupt - If the Interrupt bit is set to one an interrupt pending shall be generated when the DMA transfer count is exhausted. Devices shall not modify the behavior of this bit based on the state of the nIEN bit received in Register Host to Device FISes.

PM Port –When an endpoint device is attached via a Port Multiplier, specifies the device port address that the FIS should be delivered to or is received from. This field is set by the host for Host to Device transmission and this field is set by the Port Multiplier for Device to Host transmission. Endpoint devices shall set this field to 0h for Device to Host transmissions.

R – Reserved – shall be cleared to zero.