7-43
Register Descriptions
Completion Queue Registers
Note:
All completion queues have a fixed size of 1KByte entries.
CompletionQueueHighAddr Register
Type: R/W
Internal Registers Subgroup: Ethernet Functional Registers
Byte Address: B4h - B7h
TxCompletionQueueCtrl
Type: R/W
Internal Registers Subgroup: Ethernet Functional Registers
Byte Address: B8 - BBh
Table 7-55. CompQueueHighAddress Register
Bit(s)
rw
Reset
Value
Description/Function
31:0
r/w
x
CompQueueHighAddr[31:0]:
Upper 32-bits of address of all the
completion queues.
Table 7-56. TxCompletionQueueCtrl Register
Bit(s)
rw
Reset
Value
Description/Function
31:8
r/w
x
TxCompletionBaseAddress[31:8]:
This field contains the starting
address of the queue in host memory. It is written by the host driver
during initialization and read by the AIC-6915. The amount of host
memory allocated for the completion queue is either 4-KBytes, 8-
KBytes, or 16-KBytes (programmable by bits 5:4,
R
X
C
OMPLETION
Q1T
YPE
). The start address must be aligned to a 256-
byte boundary. The total number of completion descriptor entries in
the queue is fixed at 1024.
7
r/w
0
TxCompletion64bitAddress:
This bit indicates if the transmit
Completion Queue is located in 64-bit address space, If so, the
AIC-6915 PCI Master must use 64-bit addressing mode to access the
queue.
6
r/w
0
TxCompletionProducerWe:
When this bit is set, the software driver
is able to write the transmit completion queue producer index.
Otherwise, writes to the index are disabled. When the bit is cleared
the queue is disabled and the AIC-6915 cannot add entries to the
queue.
5
r/w
0
TxCompletionSize:
When this bit is set, each transmit completion
descriptor size is 8-bytes, which makes the entire completion queue
8-KBytes. When cleared, each transmit completion descriptor size is
4-bytes, which makes the entire completion queue 4-KBytes.
