linux-kernel - Re: [PATCH] remoteproc: qcom: Move glink

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Message-ID: <6259ebabc6183efb0045f9f990747d5e@codeaurora.org>
Date:   Tue, 23 Jul 2019 14:30:53 +0530
From:   Sibi Sankar <sibis@...eaurora.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Ohad Ben-Cohen <ohad@...ery.com>, linux-arm-msm@...r.kernel.org,
        linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Arun Kumar Neelakantam <aneela@...eaurora.org>,
        Chris Lew <clew@...eaurora.org>
Subject: Re: [PATCH] remoteproc: qcom: Move glink_ssr notification after stop

Reviewed-by: Sibi Sankar <sibis@...eaurora.org>
Tested-by: Sibi Sankar <sibis@...eaurora.org>

On 2019-07-16 10:33, Bjorn Andersson wrote:
> glink_ssr is used to signal a remote processor "A" about the stopping 
> of
> another remote processor "B", so that in the event that remote 
> processor
> B is ever booted again the fifos of the glink channel between A and B 
> is
> in a known state.
> 
> But if remote processor A receives this notification before B is
> actually stopped the newly reset fifo indices will be interpreted as
> there being "data" on the channel and either side of the channel will
> enter a fatal error handler.
> 
> Move the glink_ssr notification to the "unprepare" state of the
> rproc_subdev to avoid this issue.
> 
> This has the side effect of us not notifying the dying remote processor
> itself about its fate, which has been seen to block in certain resource
> constraint scenarios.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
>  drivers/remoteproc/qcom_common.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/remoteproc/qcom_common.c 
> b/drivers/remoteproc/qcom_common.c
> index 6a448429f223..60650bcc8c67 100644
> --- a/drivers/remoteproc/qcom_common.c
> +++ b/drivers/remoteproc/qcom_common.c
> @@ -200,7 +200,7 @@ void qcom_unregister_ssr_notifier(struct 
> notifier_block *nb)
>  }
>  EXPORT_SYMBOL_GPL(qcom_unregister_ssr_notifier);
> 
> -static void ssr_notify_stop(struct rproc_subdev *subdev, bool crashed)
> +static void ssr_notify_unprepare(struct rproc_subdev *subdev)
>  {
>  	struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev);
> 
> @@ -220,7 +220,7 @@ void qcom_add_ssr_subdev(struct rproc *rproc,
> struct qcom_rproc_ssr *ssr,
>  			 const char *ssr_name)
>  {
>  	ssr->name = ssr_name;
> -	ssr->subdev.stop = ssr_notify_stop;
> +	ssr->subdev.unprepare = ssr_notify_unprepare;
> 
>  	rproc_add_subdev(rproc, &ssr->subdev);
>  }

-- 
-- Sibi Sankar --
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.