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But in general, any ETR that can deal with multiple trace sources should support formatting, otherwise the trace will be corrupt if more than one trace source is enabled. Practically the only reason ever to have an ETR that doesn't support formatting is if the ETR is specific to a single trace source (e.g. one ETR per CPU).
Yes. We have one ETR per CPU.
I am very surprised (and thrilled) to see such topology emerging. Unfortunately it also means you will not be able to use the current coresight infrastructure (kernel and user space) without _serious_ refactoring. Your platform wouldn't happen to be in the public domain by any chance? Or perhaps Marvell would be interested in shipping a board to a selected group of people? That would help with both development and testing.
Thanks, Mathieu