The architect field defines what the ARCHID field means (the ARCHID values are specific to each architect), it's not the same as the implementer field. You need to check both if you want to know what component driver to use. The correct mask for that is 0xfff0ffff.
This is a fair point - thought at present the peripheral ID matching takes in the JDEC ID code of the component designer - in the ETM case ARM (though without a JDEC continuation code check). Given this field too is specified as "designer not implementer", it seems logically unlikely that designer != architect.
It might be exactly like that. On the system I'm using right now:
DEVARCH=0x47714a13 meaning architect=ARM architecture=ETM PIDR= <somebody else>
This is not a Cortex core designed by ARM, it's someone else's ARM compatible core and they designed their own ARM-compatible ETM. It conforms to the ETM architecture defined by ARM, so they set DEVARCH to indicate that (architect=ARM), but in the implementer/ designer code in PIDR they put their own JEDEC code.
If you've got DEVARCH, that should be all you need to select the right driver and then the driver should be able to get everything it needs from the feature ID regs. It should only need to look at implementer code / product code as a last resort for errata workarounds or similar (e.g. if the feature ID regs are known to be incorrect).
If you haven't got DEVARCH, you have to look at implementer code / product code. So for example if we see a componet with no DEVARCH but with designer=ARM product=0x961, that's "ARM product 0x961" i.e. a TMC, and we can write the driver according to the programming interface described in the manual for that product.
Al
If we did feel the need to alter the match value / mask values - this happens in the CS driver code, not in this patch - so will need to be addressed there.
Thanks
Mike
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