As to the "arm," prefix on all this - we need to double check that this is an actual arm variant - otherwise it will need to have the actual designer prefix instead. Haven't come across this variant before so need to check it is actually arm specified before claiming it as such.
So there are two ways funnels get into systems. One is from Arm's CoreSight 'toolkit' which provides all the components for the downstream trace network. In this toolkit, whether a funnel is programmable or not is a design-time option.
The other way is that some CPU clusters (not all) will have an internal non-programmable funnel to concentrate the output of all the ETMs in the cluster so the cluster only has to have one trace output bus rather than one for each core (or thread). In this case the funnel might be designed by whoever is designing the CPU and that might not be Arm. In fact, internally it might even be multiple levels of funnel.
So it's probably best to refer it in the most generic way possible. It's just a point in the trace topology at which ATB streams get merged.
Al IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.