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References: <20181005214507.26315-1-jae.hyun.yoo@linux.intel.com> <20181005214507.26315-6-jae.hyun.yoo@linux.intel.com>
In-Reply-To: <20181005214507.26315-6-jae.hyun.yoo@linux.intel.com>
From:   Brendan Higgins <brendanhiggins@google.com>
Date:   Tue, 9 Oct 2018 17:08:00 -0700
Message-ID: <CAFd5g45JkK4BnGR7yOA3eCazTZ86FyUaNdi81Ew6VBbKxS3EZA@mail.gmail.com>
Subject: Re: [PATCH i2c-next v7 5/5] i2c: aspeed: Add bus idle waiting logic
 for multi-master use cases
To:     Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Cc:     Wolfram Sang <wsa@the-dreams.de>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Joel Stanley <joel@jms.id.au>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Andrew Jeffery <andrew@aj.id.au>, linux-i2c@vger.kernel.org,
        OpenBMC Maillist <openbmc@lists.ozlabs.org>,
        devicetree <devicetree@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        linux-aspeed@lists.ozlabs.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        jarkko.nikula@linux.intel.com, james.feist@linux.intel.com,
        vernon.mauery@linux.intel.com
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On Fri, Oct 5, 2018 at 2:45 PM Jae Hyun Yoo
<jae.hyun.yoo@linux.intel.com> wrote:
>
> In multi-master environment, this driver's master cannot know
> exactly when peer master sends data to this driver's slave so a
> case can be happened that this master tries to send data through
> the master_xfer function but slave data from peer master is still
> being processed by this driver.
>
> To prevent any state corruption in the case, this patch adds
> checking code if any slave operation is ongoing and it waits up to
> the bus timeout duration before starting a master_xfer operation.
>
> Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>

Reviewed-by: Brendan Higgins <brendanhiggins@google.com>