Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master

From	Benjamin Herrenschmidt <benh@kernel.crashing.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master
Date	2017-04-05 00:30 +0200
Message-ID	<tsF7A-2v6-11@gated-at.bofh.it> (permalink)
References	(1 earlier) <tqpTk-1P5-31@gated-at.bofh.it> <tqBhL-1EG-3@gated-at.bofh.it> <tqMPU-1Sb-17@gated-at.bofh.it> <tqPkK-3s9-13@gated-at.bofh.it> <tsAAW-7Yu-23@gated-at.bofh.it>
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On Tue, 2017-04-04 at 12:32 -0500, Christopher Bostic wrote:
> Agreed that there is room for improvement.   I intend to look further 
> into your suggestions from here and our private conversation on the 
> matter and make changes as appropriate.  I have an open issue to track 
> this.  As it exists in this patch reads/writes from master to slave 
> fundamentally work.  

My understanding is they "seem to work if you get lucky with the timing
and fall apart under load". Or did I hear wrong ?

>  Given the pervasiveness and time to fully evaluate 
> and test any protocol updates I intend address this in the near future 
> with a separate follow on patch.

Please try the simple change I proposed in my email. It's a 4 or 5
lines change max to your clock_toggle function and how it's called in
send and receive. It should be trivial to check if things still "seem
to work" to begin with.

Do you have some kind of test mechanism that hammers the FSI
continuously ? Such as doing a series of putmemproc/getmemproc &
checking the values ?

Then you can run that while hammering the LPC bus and generally putting
the BMC under load and you'll quickly see if it's reliable or not.

Cheers,
Ben.

Thread

[PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Christopher Bostic <cbostic@linux.vnet.ibm.com> - 2017-03-29 19:50 +0200
  Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Joel Stanley <joel@jms.id.au> - 2017-03-30 08:00 +0200
    Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Christopher Bostic <cbostic@linux.vnet.ibm.com> - 2017-03-30 20:20 +0200
      Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2017-03-30 23:00 +0200
        Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Christopher Bostic <cbostic@linux.vnet.ibm.com> - 2017-04-04 19:40 +0200
          Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2017-04-05 00:30 +0200
            Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Christopher Bostic <cbostic@linux.vnet.ibm.com> - 2017-04-05 03:30 +0200
            Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Christopher Bostic <cbostic@linux.vnet.ibm.com> - 2017-04-09 23:30 +0200
              Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Benjamin Herrenschmidt <benh@au1.ibm.com> - 2017-04-10 00:00 +0200
              Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Benjamin Herrenschmidt <benh@au1.ibm.com> - 2017-04-10 00:00 +0200
              Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2017-04-10 00:50 +0200
      Re: [PATCH v4 19/23] drivers/fsi: Add GPIO based FSI master Joel Stanley <joel@jms.id.au> - 2017-03-31 01:00 +0200

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