Intel IXP400 manual Transmit Disconnect, Tx Done Recycling Using a Polling Mechanism

Intel® IXP400 Software

Access-Layer Components: ATM Driver Access (IxAtmdAcc) API

Transmit Done — Based on Polling Mechanism

A polling mechanism can be used instead of the threshold service to trigger the recycling of the transmitted buffers, as shown in Figure 17.

Figure 17. Tx Done Recycling — Using a Polling Mechanism

Data Client	Tx Ctrl
	Client
5: ixAtmdAccBufferReturnCB(userId, mbuf)
6: mbufProcessed	3: mbufLevel
AtmdAcc
2: ixAtmdAccTxDoneLevelQuery()
4: iixAtmdAccTxDoneDispatch(numMbuf)
1: hwSend()
	B2287-01

1.Sometime earlier, the data client sent data to transmit. Cells are now sent over the UTOPIA interface and the IXP_BUFs are now available.

2, 3.A control client does not want to use the threshold services to process the transmitted buffers. Therefore, the ixAtmdAccTxDoneQueryLevel() function can optionally be called to get the current number of IXP_BUFs already transmitted.

4.The control client requests the ixAtmdAcc to do more processing and provides a number of buffers to process as a parameter of the ixAtmdAccTxDoneDispatch() function. This function gets the transmitted buffer and retrieves the connId associated with this buffer.

5.Based on connId, ixAtmdAccTxDoneDispatch identifies the data client to which this buffer belongs. The corresponding data client’s TxDoneCallback function — as registered during a TxVcConnect — is invoked with the IXP_BUF.

This TxDoneCallback function is likely to free or recycle the chained IXP_BUFs.

6.The client gets the number of buffer processed from the control client. This number may be different to the number requested when multiple instances of the ixAtmdAccTxDoneDispatch() function are used at the same time.

4.5.2.2Transmit Disconnect

Before a client disconnects from a VC, all resources must have been recycled, as shown in Figure 18. This is done by calling the ixAtmdAccTxVcDisconnect() function until all PDUs are transmitted by the hardware and all buffers are sent back to the client.

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