linux-kernel - Re: [PATCH 04/10] remoteproc: imx

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Date:   Thu, 20 Aug 2020 13:27:08 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Peng Fan <peng.fan@....com>
Cc:     "bjorn.andersson@...aro.org" <bjorn.andersson@...aro.org>,
        "o.rempel@...gutronix.de" <o.rempel@...gutronix.de>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "linux-remoteproc@...r.kernel.org" <linux-remoteproc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.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-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH 04/10] remoteproc: imx_rproc: make syscon optional

On Thu, Aug 20, 2020 at 02:04:10AM +0000, Peng Fan wrote:
> > Subject: Re: [PATCH 04/10] remoteproc: imx_rproc: make syscon optional
> > 
> > On Wed, Aug 19, 2020 at 12:51:27AM +0000, Peng Fan wrote:
> > > > Subject: Re: [PATCH 04/10] remoteproc: imx_rproc: make syscon
> > > > optional
> > > >
> > > > Hi Peng,
> > > >
> > > > On Fri, Jul 24, 2020 at 04:08:07PM +0800, Peng Fan wrote:
> > > > > Make syscon optional, since i.MX8QM/QXP/7ULP not have SRC to
> > > > > control
> > > > M4.
> > > > > But currently i.MX8QM/QXP/7ULP not added, so still check regmap
> > > > > when start/stop to avoid unhappy things.
> > > >
> > > > On the i.MX8QM/QXP/7ULP processors, the remote processors are not
> > > > handled by the remoteproc cores, as implemented in this patch.  In
> > > > such a scenario how does the remoteproc core know the remote
> > > > processor has crashed and how does it recover from such a condition?
> > >
> > > For 7ULP dual boot case, A7 is under control of M4, so if m4 crash, I
> > > suppose
> > > A7 would not work properly.
> > 
> > In that case I assume the whole system gets rebooted, which puts the A7 in a
> > state where it can "attach" with the M4 again.
> 
> Yes. Whole system get rebooted.
> 
> > 
> > >
> > > For 8QM/QXP partition case, M4 is in a standalone partition, if M4
> > > crash or reboot, the system controller unit will restart M4 and notify
> > > Acore that M4 restart.
> > 
> > And how does that notification work exactly?  Does rproc_report_crash() get
> > called somewhere in that process in order for the remoteproc core to attach
> > to the M4 again?
> 
> Yes. We registered a interrupt notification handler with system controller unit.
> When M4 rebooted, the system controller will raise interrupt to A53 core.
> Then the notification callback will be invoked, the callback will call
> rproc_report_crash. I not included this part code in the patchset, since
> this patchset is to add initial support for 8M case.

All this information is really appreciated.

> 
> Thanks,
> Peng.
> 
> > 
> > Many thanks for the help,
> > Mathieu
> > 
> > >
> > > Thanks,
> > > Peng.
> > >
> > > >
> > > > Thanks,
> > > > Mathieu
> > > >
> > > > >
> > > > > Reviewed-by: Richard Zhu <hongxing.zhu@....com>
> > > > > Signed-off-by: Peng Fan <peng.fan@....com>
> > > > > ---
> > > > >  drivers/remoteproc/imx_rproc.c | 11 +++++++++--
> > > > >  1 file changed, 9 insertions(+), 2 deletions(-)
> > > > >
> > > > > diff --git a/drivers/remoteproc/imx_rproc.c
> > > > > b/drivers/remoteproc/imx_rproc.c index 82594a800a1b..4fad5c0b1c05
> > > > > 100644
> > > > > --- a/drivers/remoteproc/imx_rproc.c
> > > > > +++ b/drivers/remoteproc/imx_rproc.c
> > > > > @@ -162,6 +162,9 @@ static int imx_rproc_start(struct rproc *rproc)
> > > > >  	struct device *dev = priv->dev;
> > > > >  	int ret;
> > > > >
> > > > > +	if (!priv->regmap)
> > > > > +		return -EOPNOTSUPP;
> > > > > +
> > > > >  	ret = regmap_update_bits(priv->regmap, dcfg->src_reg,
> > > > >  				 dcfg->src_mask, dcfg->src_start);
> > > > >  	if (ret)
> > > > > @@ -177,6 +180,9 @@ static int imx_rproc_stop(struct rproc *rproc)
> > > > >  	struct device *dev = priv->dev;
> > > > >  	int ret;
> > > > >
> > > > > +	if (!priv->regmap)
> > > > > +		return -EOPNOTSUPP;
> > > > > +
> > > > >  	ret = regmap_update_bits(priv->regmap, dcfg->src_reg,
> > > > >  				 dcfg->src_mask, dcfg->src_stop);
> > > > >  	if (ret)
> > > > > @@ -325,9 +331,10 @@ static int imx_rproc_probe(struct
> > > > > platform_device
> > > > *pdev)
> > > > >  	regmap = syscon_regmap_lookup_by_phandle(np, "syscon");
> > > > >  	if (IS_ERR(regmap)) {
> > > > >  		dev_err(dev, "failed to find syscon\n");
> > > > > -		return PTR_ERR(regmap);
> > > > > +		regmap = NULL;
> > > > > +	} else {
> > > > > +		regmap_attach_dev(dev, regmap, &config);
> > > > >  	}
> > > > > -	regmap_attach_dev(dev, regmap, &config);
> > > > >
> > > > >  	/* set some other name then imx */
> > > > >  	rproc = rproc_alloc(dev, "imx-rproc", &imx_rproc_ops,
> > > > > --
> > > > > 2.16.4
> > > > >