linux-kernel - RE: [PATCH 3/9] remoteproc: add support to skip firmware load when recovery

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Message-ID: <AM0PR04MB44810B020E8C4F099D8F47A588EF0@AM0PR04MB4481.eurprd04.prod.outlook.com>
Date:   Sun, 23 Feb 2020 00:01:38 +0000
From:   Peng Fan <peng.fan@....com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
CC:     "ohad@...ery.com" <ohad@...ery.com>,
        "bjorn.andersson@...aro.org" <bjorn.andersson@...aro.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        dl-linux-imx <linux-imx@....com>,
        "linux-remoteproc@...r.kernel.org" <linux-remoteproc@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 3/9] remoteproc: add support to skip firmware load when
 recovery

Hi Mathieu,

> Subject: Re: [PATCH 3/9] remoteproc: add support to skip firmware load when
> recovery
> 
> Hi Peng,
> 
> On Wed, Feb 19, 2020 at 03:27:39PM +0800, peng.fan@....com wrote:
> > From: Peng Fan <peng.fan@....com>
> >
> > Remote processor such as M4 inside i.MX8QXP is not handled by Linux
> > when it is configured to run inside its own hardware partition by
> > system control unit(SCU). So even remote processor crash reset, it is
> > handled by SCU, not linux. To such case, firmware load should be
> > ignored, So introduce skip_fw_load_recovery and platform driver should
> > set it if needed.
> 
> For now I will not comment on the code - I just need clarifications on the
> scenario.
> 
> In the specific case you are trying to address here, I understand that when the
> M4 crashes, the SCU will recognize that and reload the MCU firmware. Does
> the SCU also start the MCU or is that left to the remoteproc subsystem?

SCU starts M4. Linux has no permission to start/stop M4 from hardware
perspective with hardware partition feature enabled.

Regards,
Peng.

> 
> Thanks,
> Mathieu
> 
> >
> > Signed-off-by: Peng Fan <peng.fan@....com>
> > ---
> >  drivers/remoteproc/remoteproc_core.c | 19 +++++++++++--------
> >  include/linux/remoteproc.h           |  1 +
> >  2 files changed, 12 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/remoteproc/remoteproc_core.c
> > b/drivers/remoteproc/remoteproc_core.c
> > index 876b5420a32b..ca310e3582bf 100644
> > --- a/drivers/remoteproc/remoteproc_core.c
> > +++ b/drivers/remoteproc/remoteproc_core.c
> > @@ -1678,20 +1678,23 @@ int rproc_trigger_recovery(struct rproc *rproc)
> >  	if (ret)
> >  		goto unlock_mutex;
> >
> > -	/* generate coredump */
> > -	rproc_coredump(rproc);
> > +	if (!rproc->skip_fw_load_recovery) {
> > +		/* generate coredump */
> > +		rproc_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;
> > +		/* 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->skip_fw_load_recovery)
> > +		release_firmware(firmware_p);
> >
> >  unlock_mutex:
> >  	mutex_unlock(&rproc->lock);
> > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > index 4fd5bedab4fa..fe6ee253b385 100644
> > --- a/include/linux/remoteproc.h
> > +++ b/include/linux/remoteproc.h
> > @@ -514,6 +514,7 @@ struct rproc {
> >  	bool has_iommu;
> >  	bool auto_boot;
> >  	bool skip_fw_load;
> > +	bool skip_fw_load_recovery;
> >  	struct list_head dump_segments;
> >  	int nb_vdev;
> >  };
> > --
> > 2.16.4
> >