Intel® IXP400 Software

Access-Layer Components: HSS-Access (IxHssAcc) API

Figure 67. HSS Packetized Receive Buffering

IXP_BUFs

 

4. Data (HDLC frame or RAW block)

HssPacketizedRx

for each packet-pipe written to

appropriate mbuf, specified by

queue

descriptor.

 

Steps 3 and 4 repeated to chain

 

mbufs as required.

5.Descriptor returned when entire frame/

 

block received.

 

 

 

If chaining, only first

 

 

 

descriptor returned.

NPE-A

2. HDLC frame processing

 

 

 

 

Hss Packetized Rx

performed on each

 

 

Operation

packet-pipe configured

 

 

 

for HDLC mode

HssPacketizedRxFree0 -

3. Free descriptor

 

 

HssPacketizedRxFree3

 

 

read from packet-

 

 

queues

 

 

pipe-specific,

 

 

 

 

 

 

"free" queue

1. Data received

 

 

 

 

 

 

from HSS port

 

 

 

Frame 0

 

 

 

 

Frame 1

 

 

...

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

F0-

F0-

F0-

 

...

F0-

F1-

F1-

F1-

 

...

F1-

TSa

TSb

TSc

 

TSz

TSa

TSb

TSc

 

TSz

 

 

 

 

 

 

 

 

 

 

 

 

 

 

HSS Port Serial Data Stream

(TSa, TSb, ... = timeslots configured as "HDLC")

B2382-03

For Tx, buffers are allocated from the IXP_BUF pool by calling IX_OSAL_MBUF_POOL_GET(). Data for transmitting can be put into the IXP_BUF by using IX_OSAL_MBUF_MDATA(). If the client data is too large to fit into one buffer, multiple buffers can be obtained from the pool and made into a chained IXP_BUFs by using IX_OSAL_MBUF_PKT_LEN() and IX_OSAL_MBUF_NEXT_BUFFER_IN_PKT_PTR(). The whole chained IXP_BUF can be passed to IxHssAcc for transmission by calling ixHssAccPktPortTx().

A Tx callback function is also registered when ixHssAccPktPortConnect() is called before the service is enabled. When a chained IXP_BUF is done with transmitting, the callback function is called and the buffers can be returned to the IXP_BUF pool. The packetized Transmit data flow is described in Figure 68.

Programmer’s Guide

IXP400 Software Version 2.0

April 2005

 

Document Number: 252539, Revision: 007

213

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Intel IXP400 manual HSS Packetized Receive Buffering