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FUJITSU MHV2060BH User Manual

Page 95

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5.2 Logical Interface

C141-E224

5-19

The host uses the DMA Active - Device to Host FIS layout. This FIS instructs
the host to continue transferring DMA data from the host to the device.

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
1

3
0

2
9

2
8

2
7

2
6

2
5

2
4

2
3

2
2

2
1

2
0

1
9

1
8

1
7

1
6

1
5

1
4

1
3

1
2

1
1

1
0

9 8 7 6 5 4 3 2 1 0

Reserved (0)

Reserved (0)

A I D Reserved (0)

FIS Type (41h)

0

0 TAG

1

0

2

Reserved (0)

3

DMA Buffer Offset

4

DMA Transfer Count

5

Reserved (0)

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.

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