Doubt about the qmss example

Eric,

Replies:

1) See Table 5-1.  The queue manager has dedicated queues that drive each of the various pktDMA Tx channels. It is a hardcoded connection between queue number and Tx channel.

2) Yes, the PDSPs run firmware (not only Accumulation firmware). In the case of the QMSS pktDMA, the Rx side is directly connected to the Tx side because its streaming i/f (interface) is wired together to create a loopback condition. So sending a descriptor to an enabled Tx channel will cause it to pop out on the Rx side, depending on the contents of the Tx descriptor and the Rx Flow programming.

3) The pktDMA views the QM as logical queue managers, 4096 queues each. To access all 8192 queues you must configure the second logical queue manager (the first is mapped to queue 0 during reset). Logical queue managers allow the pktDMA to send to queue managers on other devices that are connected together.

4) Not sure what the question is, but I think it may have been answered in reply #1.

5) i/f is "interface". In this case, the "streaming interface" connects a pktDMA to its host peripheral, or as mentioned above, to itself in the QMSS pktDMA.

  -dave

Answers are below:

 1、It use the queue 800 as a Tx queue, and how the navigator know this queue is a Tx queue? Why any descriptor push into this queue will deal with as a DMA source information?

AVM: Please check Table 5-1 for the Queue map information.

       2、The PDSP1 run the accumulator firmware, it just monitor the Rx queue, how the Tx descriptor pass to the Rx queue?

AVM: For infrastructure mode the TX channel N is hardwired to RX channel N. So one you push a descriptor to the TX queue, it will be pushed to the RX queue connected to that channel.

       3、Why configure the logical queue managers? How the use it?

AVM: Please check section 6.2.6 for this. Basically it is SW to HW mapping. For all purposes, you can avoid configuring and assume only one instance of QM is available.

       4、The code just enable the Tx channel, Is there  no need to indicate a Tx queue associate with a Tx channel?

AVM: Each queue is mapped to a TX channel. So queue 800 is mapped to TX channel 0 and so on.

       5、stream i/f appear in the document,  what the i/f mean?

AVM: I/F mean interface. It actually ties up the tx channel to a particular RX flow. For example you can have multiple RX flow for RX channel 0 and the tx channel decides which flow to use.

Hope this helps.

Thanks,

Arun.