Intel IXP400 manual Sending an NPE Message with Response, Client, Customer / Demo Code, IxNpeMh

Intel® IXP400 Software

Access-Layer Components: NPE Message Handler (IxNpeMh) API

Figure 71. Message from Intel XScale® Core Software Client to an NPE

	Client
	1. Send Message
Customer / Demo Code
0x00 callback		callback n+k
0x01 callback		...
...		callback n+1
0xff callback	IxNpeMh	callback n
	2. Send Message
Access Driver
NPEs
NPE A	NPE B	NPE C
		B2395-01

15.5.2Sending an NPE Message with Response

In this case, the client’s message requires a response from the NPE. The scenario (as shown in Figure 72) is:

1.The client sends a message to the IxNpeMh component, specifying the destination NPE and a response callback.

2.The IxNpeMh component checks that the NPE can accept a message. If the component cannot accept a message, the send fails.

3.The IxNpeMh component adds the response callback to the end of the solicited callback list and sends the message to the NPE.

4.After some time, the NPEs “outFIFO not empty” interrupt invokes the IxNpeMh component’s ISR.

5.Within the ISR, the IxNpeMh component receives a message from the specific NPE.

6.The IxNpeMh component checks if this message ID has an unsolicited callback registered for it.

If the messages has an unsolicited callback registered, the message is unsolicited. (See “Receiving Unsolicited Messages from an NPE to Client Software” on page 229.)

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