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5.2.3.5 DMA Setup - Device to Host or Host to Device (Bidirectional)
The DMA Setup - Device to Host or Host to Device FIS has the following layout:
3
3
2
2
2
2
2
1
0
9
8
7
6
5
Reserved (0)
0
1
2
3
4
5
6
Figure 5.7 DMA Setup - Device to Host or Host to Device FIS layout
The DMA Setup - Device to Host or Host to Device FIS communicates the start of
a first-party DMA access to the host system. This FIS is used to request the host
system or device to set up the DMA controller before the start of a DMA data
transfer.
A - Auto Active bit. If this bit is cleared ("0" is set for the bit), it indicates that a
DMA Active FIS transfer is required before a Data FIS transfer.
D - Direction bit. If this bit is set ("1" is set for the bit), it indicates that the data
transfer direction is from the device to the host system.
C141-E254
2
2
2
2
2
1
1
1
1
4
3
2
1
0
9
8
7
6
Reserved (0)
0
Reserved (0)
DMA Buffer Offset
DMA Transfer Count
Reserved (0)
1
1
1
1
1
1
9 8 7 6 5 4 3 2 1 0
5
4
3
2
1
0
A I D Reserved (0)
0
5.2 Logical Interface
FIS Type (41h)
TAG
5-19
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