Intel IXP400 manual Receive Flow, Ethernet Receive Frame API Overview

Intel® IXP400 Software

Access-Layer Components: Ethernet Access (IxEthAcc) API

Figure 51. Ethernet Receive Frame API Overview

1.IxNpeDlNpeInitAndStart (ImageID)

2.IxEthAccPortInit (portId)

3.IxEthAccPortRxDoneCallbackRegister (portID, callbackfn, callbacktag)

4.IxEthAccPortRxFreeReplenish

(portID, ixp_buf *)

5.IxEthAccPortEnable (portId)

Rx

Data Client

8.free ixp_buf

7.(* IxEthAccPortRxCallback) (callbacktag, ixp_buf *, portID)

IxEthAcc

ixp_buf made available to Rx frame

Ethernet frame received

Receive

6.

B2365-02

9.5.3.1Receive Flow

1.Proper NPE images must be downloaded to the NPEs and initialized.

2.The receiving port must be initialized.

3.Register a callback function for the port. This function will be called each time a frame is received.

4.Preload free receive buffers for use by IxEthAcc.

5.After configuring the receiving port and pre-loading buffers, the receiving port is enabled, allowing traffic to be received.

6.An Ethernet frame is received on the wire and placed in the IxQMgr Rx queue.

7.The callback function is called for each frame, being passed a pointer to that

IX_OSAL_MBUF. The callback function can now process and/or de-multiplex the incoming frame(s).

8.The upper-level user or OS processes must recover the receive buffers once processing of the frame is completed, and replenish the RxFree queue using IxEthAccPortRxFreeReplenish() as needed.

Note: The process for multi-buffer receive callback is similar to what is described above, with the exception that the multi-buffer callback should not be invoked for every frame. A polling dispatch mechanism should be used.

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