> This was my initial approach. It gets quite messy though. Since taggers > can be modules, there is no way of knowing if a supplied protocol name > is garbage ("asdf"), or just part of a module in an initrd that is not > loaded yet when you are probing the tree.
Hi Tobias I don't think that is an issue. We currently lookup the tagger in dsa_port_parse_cpu(). If it does not exist, we return -EPROBE_DEFER. Either it eventually gets loaded, or the driver core gives up. I don't see why the same cannot be done for a DT property. If dsa_find_tagger_by_name() does not find the tagger return -EPROBE_DEFER. Garbage will result in the switch never loading, and the DT writer will go find their typo. > Even when the tagger is available, there is no way to verify if the > driver is compatible with it. I would of though, calling the switch drivers change_tag_protocol() op will that for you. If it comes back with -EINVAL, or -EOPNOTSUPP, you know it is not compatible. So i guess i would keep all the code you are adding here to allow dynamic setting of the protocol. And add more code in dsa_switch_parse_of() to parse the optional tagging protocol name, error out -EPROBE_DEFER if it is not known yet, otherwise store it away in something like dst->tag_ops_name. And then probably in dsa_switch_setup(), if dst->tag_ops_name is not NULL, invoke the dynamic change code to perform the actual change. Andrew