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From:   Loic Poulain <loic.poulain@linaro.org>
Date:   Thu, 4 Mar 2021 09:43:52 +0100
Message-ID: <CAMZdPi8s8Sp1eaqjTbxUtqiNgDXFa5a+GJnp-LmrDc-8ORCOtw@mail.gmail.com>
Subject: Re: [PATCH v6 3/4] bus: mhi: core: Process execution environment
 changes serially
To:     Bhaumik Bhatt <bbhatt@codeaurora.org>
Cc:     Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Hemant Kumar <hemantk@codeaurora.org>,
        Jeffrey Hugo <jhugo@codeaurora.org>,
        open list <linux-kernel@vger.kernel.org>,
        =?UTF-8?B?Q2FybCBZaW4o5q635byg5oiQKQ==?= <carl.yin@quectel.com>,
        Naveen Kumar <naveen.kumar@quectel.com>
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On Thu, 25 Feb 2021 at 00:23, Bhaumik Bhatt <bbhatt@codeaurora.org> wrote:
>
> In current design, whenever the BHI interrupt is fired, the
> execution environment is updated. This can cause race conditions
> and impede ongoing power up/down processing. For example, if a
> power down is in progress, MHI host updates to a local "disabled"
> execution environment. If a BHI interrupt fires later, that value
> gets replaced with one from the BHI EE register. This impacts the
> controller as it does not expect multiple RDDM execution
> environment change status callbacks as an example. Another issue
> would be that the device can enter mission mode and the execution
> environment is updated, while device creation for SBL channels is
> still going on due to slower PM state worker thread run, leading
> to multiple attempts at opening the same channel.
>
> Ensure that EE changes are handled only from appropriate places
> and occur one after another and handle only PBL modes or RDDM EE
> changes as critical events directly from the interrupt handler.
> Simplify handling by waiting for SYS ERROR before handling RDDM.
> This also makes sure that we use the correct execution environment
> to notify the controller driver when the device resets to one of
> the PBL execution environments.
>
> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>

Looking good now

Reviewed-by: Loic Poulain <loic.poulain@linaro.org>