Intel IXP400 manual Document Number 252539, Revision 209

Intel® IXP400 Software

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

Here is an example:

// get a buffer

IX_OSAL_MBUF *rxBuffer;

rxBuffer = IX_OSAL_MBUF_POOL_GET(poolId);

//IxHssAcc component needs to know the capacity of the IXP_BUF IX_OSAL_MBUF_MLEN(rxBuffer) = IX_HSSACC_CODELET_PKT_BUFSIZE;

//give the Rx buffer to the HssAcc component status = ixHssAccPktPortRxFreeReplenish (hssPortId, hdlcPortId, rxBuffer);

Usually, an Rx thread is created to handle the HSS packetized service, namely, to handle all the callback functions registered with ixHssAccPktPortConnect(). The thread will be waiting for a semaphore. When any one of the call back functions is executed by the HSS component, it will put the information from IxHssAcc into a structure, and send a semaphore to the thread. Then the callback function returns so that IxHssAcc can continues its own tasks. The Rx thread, after receiving the semaphore, will wake up, take the parameters from the structure passed by the callback function, and perform Rx data processing and error handling.

When data is received, rxCallback() is called. It passes the received data in the form of a IXP_BUF to the client. The IXP_BUF passed back to the client could contain a chain of IXP_BUF, depending on the packet size received. IX_OSAL_MBUF_NEXT_BUFFER_IN_PKT_PTR() can be used to get access to each of the IXP_BUF in the chained buffer, and IX_OSAL_MBUF_MDATA() can be used to get access to each data value. The IXP_BUF is returned to the buffer pool by using IX_OSAL_MBUF_POOL_PUT_CHAIN().

Here is an example:

IX_OSAL_MBUF *buffer,

IX_OSAL_MBUF *rxBuffer;

//go through each buffer in the chained buffer for (rxBuffer = buffer;

(rxBuffer != NULL) && (pktStatus == IX_HSSACC_PKT_OK); rxBuffer = IX_OSAL_MBUF_NEXT_BUFFER_IN_PKT_PTR(rxBuffer))

for (wordIndex =0;wordIndex<(IX_OSAL_MBUF_MLEN(rxBuffer) / 4); wordIndex++)

{ // get the values in the buffer IXP_BUF

value = ((UINT32 *)IX_OSAL_MBUF_MDATA(rxBuffer))[wordIndex];

}

//free the chained buffer

IX_OSAL_MBUF_POOL_PUT_CHAIN(buffer);

rxCallback() also passes the packet status and the number of errors that NPE receives. The packet status is used to determine if the packet received is good or bad, and the client can call function ixHssAccLastErrorRetrievalInitiate() to initiate the retrieval of the last HSS error.

When the Rx buffer queue is running low, rxFreeLowCallback() is called. Then, the client can call IX_OSAL_MBUF_POOL_GET() and ixHssAccPktPortRxFreeReplenish() to fill up the Rx queue again.

Programmer’s Guide	IXP400 Software Version 2.0	April 2005
	Document Number: 252539, Revision: 007	209