P4080 PCIe Adapter SDK User Guide Production Release
P4080 PCIe Adapter SDK User Guide Production Release
P4080 PCIe Adapter SDK User Guide Production Release
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Freescale Semiconductor<br />
Rx Path<br />
qman_poll() API invokes the FQ specific callbacks registered by Ethernet Hardware Function<br />
Library during FQ init. In each callback invocation, the Rx Flow Table is looked up to determine<br />
the corresponding Host Rx ring ID.<br />
For every Ethernet Rx packet, the pkt_drv_enqueue_host_ring() API is invoked to transfer the Rx<br />
packet to host memory. In this API, it is verified if the Rx ring has some free FDs. If there are free<br />
FDs, the DMA of Rx data is initiated from <strong>P4080</strong> to Host memory by obtaining the Host address<br />
from Rx shadow ring’s FD. The necessary fields inFD of the Host Rx Descriptor ring are modified<br />
and the Host producer index is updated.<br />
The dma_channel_poll() API, invoked by the application thread checks for DMA completions. If it<br />
finds Rx DMA completions, an MSI interrupt is sent to the Host to notify of an Rx packet.<br />
© Freescale Semiconductor, Inc., 2011. All rights reserved.<br />
Freescale Confidential Proprietary Page 20
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