Hyperlink hang on C6678

Juergen,

Is the issue re-producible in C6678 EVM with MCSDK example? If yes, please post the procedure to re-produce. Thank you.

Hi Ganapathi,

I'm sorry, but I do not understand your answer. Which reset bit needs to be toggled?

We tried Control Register reset bit but that had no effect.

Kind regards,

one and zero

Hi,

sorry your answer is not clarifying the issue. Is Control Register reset bit clearing the nfempty1 bit or not? Our observation is that it's not. Is this supposed to work? According to documentation I would say yes. From the Users Guide: "When this bit is set, all internal state machines are reset"
Please confirm if the Control Register reset bit is actually clearing the nfempty1 bit.
If not please document it accordingly.
As of now the only way to clear it seems to be a HW reset.

Kind regards,
one and zero

one and zero,

From my experience, when the Serdes Tx parameters configured are too bad, sometimes I will come into the above situation, e,g., Status register: 0x04402097 where nfempty1 bit is set.

In the following steps I tried to recover this by doing Hyperlink reset via Control Register bit 0 from both-end. My observation is that this nfempty1 bit can't be cleared.

I believe in document, reset to 0 means HW reset, not SW reset.

Regards, Eric

Hi

I provided some suggestions offline on possible PSC initiated localized reset for the module.

We got additional clarity from the IP owner on the working of the software reset - which I am pasting here

The reset bit is not intended to be a fix for link failures; it is intended to be used for changing modes. That is when entering loopback, the reset bit will inform the remote of a shutdown and properly bring down both ends of the link.

The serial_stop bit is intended to stop local activity from being sent to the remote. It should be set prior to setting the reset or loopback bits to ensure local transactions have completed.

The rpend bit indicate that there are transaction in flight, and when set bringing down the link or resetting the module this should be cleared, otherwise it will cause the internal system interconnect bus to never get the response. Remote Pending Request, indicates that a remote operation is currently pending or in flight. The user should monitor this bit after setting serial_stop and before changing iloop or reset register bits.

The only state machines in Hyperlink are in the serial MAC and PCS layers. The reset only resets the serial logic. It does not flush outstanding transactions nor does it reset registers. The only way to reset the internal interconnect bus interface is to reset the module. But resetting the module will indeed flush any pending request, and cause the remote to see a link failure.

Since the Hyperlink binds the busses in the two devices together, in the catastrophic case of a link failure both devices should be reset.

The link failing is the root issue, diagnosing this and resolving it is key.