Details:

The CPSW offers two mechanisms for communicating packet ingress timestamp information to the host.

The first mechanism is via the CPTS Event FIFO which records timestamps when triggered by certain events. One such event is the reception of an Ethernet packet with a specified EtherType field. Most commonly this is used to capture ingress timestamps for PTP packets. With this mechanism the host must read the timestamp (from the CPTS FIFO) separately from the packet payload which is delivered via DMA. This mode is supported and is not affected by this errata.

The second mechanism is to enable receive timestamps for all packets, not just PTP packets. With this mechanism the timestamp is delivered alongside the packet payload via DMA. This second mechanism is the subject of this errata.

When the CPTS host timestamp is enabled, every packet to the internal CPSW port FIFO requires a timestamp from the CPTS. When the packet preamble is corrupted due to EMI or any other corruption mechanism a timestamp request may not be sent to the CPTS. In this case the CPTS will not produce the timestamp which causes a lockup condition in the CPSW port FIFO. When the CPTS host timestamp is disabled by clearing the tstamp_en bit in the CPTS_CONTROL register the lockup condition is prevented from occurring.

Workaround(s):

Ethernet to host timestamps must be disabled.

CPTS Event FIFO timestamping can be used instead of CPTS host timestamps.