Freescale Semiconductor MPC8313E PowerQUICC II Pro Family Reference Manual page 886

Enhanced Three-Speed Ethernet Controllers
Access Index
RQFAR
15.6.4.2.1 Filing Rules
Unless the filer is disabled, every received frame from the Ethernet MAC initiates a search of the receive
queue filer table, starting at entry 0. The table search is terminated as soon as an entry is found whose
contents match a property of the frame. Accordingly, software must guarantee that at least one entry results
in a match—even if only to set a default receive queue index.
Since eTSEC searches the table at a rate of two entries every system clock cycle, all 256 entries can be
searched in the time taken to receive a 64-byte Ethernet frame.
Each entry of the receive queue filer table specifies a simple match rule for determining how to process
the received frame. The elements of a filing rule, expressed in the RQCTRL and RQPROP fields, are
summarized as follows:
• The PID field in RQCTRL identifies what property is being matched against RQPROP. The eTSEC
supports 16 properties, some of which are different portions of the same header field. Reserved or
unused bits in RQPROP are read as zero. See
Property Register (RQFPR)," on page 15-57
values.
• The Q field in RQCTRL identifies which one of 64 virtual receive queues the frame should be filed
to (sent through DMA) in the event of a filing rule match that accepts the frame. The physical
RxBD ring this queue maps to is controlled by the RCTRL[FSQEN] bit. If RCTRL[FSQEN] = 0,
the three least significant bits of the Q field indicate which physical RxBD ring hosts the queue. If
RCTRL[FSQEN] = 1, RxBD ring 0 hosts all receive queues, but the RxFCB[RQ] field allows
software to distinguish queues by ID. In all cases if Q maps to a RxBD ring that is not currently
enabled, the frame is discarded with an IEVENT[FIQ] error.
• The REJ field in RQCTRL controls whether the frame is to be rejected (REJ = 1) or filed (REJ =
0) upon a filing rule match. Rejected frames occupy Rx FIFO space, but do not consume memory
bus cycles.
• The CMP field in RQCTRL determines how property PID is compared against RQPROP. Equality,
inequality, greater-or-equal, and less-than compares are available.
MPC8313E PowerQUICC™ II Pro Integrated Processor Family Reference Manual, Rev. 2
15-168
Entry 0
Entry 1
Entry 2
entry 255
Control/interpretation
(Access through RQFCR)
Figure 15-138. Structure of the Receive Queue Filer Table
32 Bits 32 Bits
RQCTRL RQPROP
RQCTRL RQPROP
RQCTRL RQPROP
RQCTRL RQPROP
Section 15.5.3.3.8, "Receive Queue Filer Table
for a list of all properties and their associated PID
Filer
Table
Search
Sequence
Property Constant
(Access through RQF
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