Messages in this thread | | | Subject | Re: [PATCH v10 0/7] Add Fieldbus subsystem + support HMS Profinet card | From | "Enrico Weigelt, metux IT consult" <> | Date | Tue, 16 Apr 2019 23:18:10 +0200 |
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On 16.04.19 20:56, Sven Van Asbroeck wrote:
>> By the way: any special reason for doing this via device instead of >> socket (like we have w/ can) ? >> > > A fieldbus_dev device communicates with its controller through a section > of shared memory (process memory). It just felt more logical to model > this as a device which acts like a file. When you read/write the file, > you read/write the process memory underneath.
Yeah, that sounds logical. By the way: could we also mmap() that device?
Okay that's just a purely academical idea here, but I'm curious whether that would make a notable difference in performance.
Yet another question: does each fieldbus_dev instance talk to exactly one plc process memory, or can there be many ?
Having separate device nodes per plc process memory seems a good idea for finer access control (via chown+friends).
--mtx
-- Enrico Weigelt, metux IT consult Free software and Linux embedded engineering info@metux.net -- +49-151-27565287
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