Injection of packets into DPAA fabric possible?

[christiankeller]

We have a T2081 device which has a custom FPGA HW attached via PCIe. The device delivers UDP frames which have to be output on one of the Ethernet devices. Currently we do this in a kernel / userspace software component which does use a lot of CPU time.

We wonder whether it is possible to 'inject' the packets directly from PCIe into the FMAN stack via a DMA setup or something similar.

Is there a way to efficiently move the data into the network hardware without going through the whole network stack in software?

[bpe]

FMAN utilizes it's own DMA to fetch network data into internal
storages for handling. There is no way replace that internal FMAN
DMA with any external DMA. The best an external DMA can do is,
move packets into the local (to your T2081) DDR memory, from where
FMAN DMA will take them for processing.    

DPAA exchanges packets with the outside world via QMAN SW portals.
The concept is described in T2080DPAARM, Section 3.3.8. The interface
organization is too sophisticated to control it by a DMA engine, but
if your PCI card has a processor on it, you can use that processor
to control a QMAN Software portal. Anyway, through a QMAN portal
you only inform FMAN of the availability of a new frame. The actual
handling is done by FMAN and FMAN DMA. If the task is just to send a packet out,
you can put (enqueue) a frame onto a queue associated with an egress hardware
port. If you wish FMAN to parse the frame, you should enqueue to an
O/H port. See T2080DPAARM, Section 5.3.1 for more details.

Have a great day,
Platon

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------