linux-kernel - Re: [PATCH V2 2/2] remoteproc: support attach recovery after rproc crash

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Date:   Wed, 9 Mar 2022 11:39:19 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc:     bjorn.andersson@...aro.org, arnaud.pouliquen@...s.st.com,
        linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        peng.fan@....com
Subject: Re: [PATCH V2 2/2] remoteproc: support attach recovery after rproc crash

On Mon, 7 Mar 2022 at 23:08, Peng Fan (OSS) <peng.fan@....nxp.com> wrote:
>
> From: Peng Fan <peng.fan@....com>
>
> Current logic only support main processor to stop/start the remote
> processor after rproc crash. However to SoC, such as i.MX8QM/QXP, the
> remote processor could do attach recovery after crash and trigger watchdog
> reboot. It does not need main processor to load image, or stop/start M4
> core.
>
> Introduce two functions: rproc_attach_recovery, rproc_firmware_recovery
> for the two cases. Firmware recovery is as before, let main processor to
> help recovery, while attach recovery is recover itself withou help.
> To attach recovery, we only do detach and attach.
>
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>
> V2:
>  use rproc_has_feature in patch 1/2
>
>  drivers/remoteproc/remoteproc_core.c | 67 ++++++++++++++++++++--------
>  1 file changed, 48 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 69f51acf235e..366fad475898 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1887,6 +1887,50 @@ static int __rproc_detach(struct rproc *rproc)
>         return 0;
>  }
>
> +static int rproc_attach_recovery(struct rproc *rproc)
> +{
> +       int ret;
> +
> +       mutex_unlock(&rproc->lock);
> +       ret = rproc_detach(rproc);
> +       mutex_lock(&rproc->lock);
> +       if (ret)
> +               return ret;
> +
> +       if (atomic_inc_return(&rproc->power) > 1)
> +               return 0;
> +
> +       return rproc_attach(rproc);
> +}
> +
> +static int rproc_firmware_recovery(struct rproc *rproc)
> +{
> +       const struct firmware *firmware_p;
> +       struct device *dev = &rproc->dev;
> +       int ret;
> +
> +       ret = rproc_stop(rproc, true);
> +       if (ret)
> +               return ret;
> +
> +       /* generate coredump */
> +       rproc->ops->coredump(rproc);
> +
> +       /* load firmware */
> +       ret = request_firmware(&firmware_p, rproc->firmware, dev);
> +       if (ret < 0) {
> +               dev_err(dev, "request_firmware failed: %d\n", ret);
> +               return ret;
> +       }
> +
> +       /* boot the remote processor up again */
> +       ret = rproc_start(rproc, firmware_p);
> +
> +       release_firmware(firmware_p);
> +
> +       return ret;
> +}
> +
>  /**
>   * rproc_trigger_recovery() - recover a remoteproc
>   * @rproc: the remote processor
> @@ -1901,7 +1945,6 @@ static int __rproc_detach(struct rproc *rproc)
>   */
>  int rproc_trigger_recovery(struct rproc *rproc)
>  {
> -       const struct firmware *firmware_p;
>         struct device *dev = &rproc->dev;
>         int ret;
>
> @@ -1915,24 +1958,10 @@ int rproc_trigger_recovery(struct rproc *rproc)
>
>         dev_err(dev, "recovering %s\n", rproc->name);
>
> -       ret = rproc_stop(rproc, true);
> -       if (ret)
> -               goto unlock_mutex;
> -
> -       /* generate coredump */
> -       rproc->ops->coredump(rproc);
> -
> -       /* load firmware */
> -       ret = request_firmware(&firmware_p, rproc->firmware, dev);
> -       if (ret < 0) {
> -               dev_err(dev, "request_firmware failed: %d\n", ret);
> -               goto unlock_mutex;
> -       }
> -
> -       /* boot the remote processor up again */
> -       ret = rproc_start(rproc, firmware_p);
> -
> -       release_firmware(firmware_p);
> +       if (rproc_has_feature(rproc, RPROC_FEAT_ATTACH_RECOVERY))
> +               ret = rproc_attach_recovery(rproc);
> +       else
> +               ret = rproc_firmware_recovery(rproc);

Should I assume this set, which is labeled V2, replaces this other
patch [1] that is also labeled V2, sent out on January 26th?  If so,
why are they both labeled with the same tag and why isn't there a
cover letter to clearly state your intent?  More importantly, why am I
having this conversation with an experienced kernel developer that
should know better?

Any reason I should not move this work to the very bottom of my patch
queue or better yet, simply drop it?

[1]. https://lore.kernel.org/lkml/20220207173456.GA3355405@p14s/t/

>
>  unlock_mutex:
>         mutex_unlock(&rproc->lock);
> --
> 2.30.0
>