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From:   Peng Fan <peng.fan@nxp.com>
To:     Mathieu Poirier <mathieu.poirier@linaro.org>
CC:     "bjorn.andersson@linaro.org" <bjorn.andersson@linaro.org>,
        "o.rempel@pengutronix.de" <o.rempel@pengutronix.de>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "linux-remoteproc@vger.kernel.org" <linux-remoteproc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "shawnguo@kernel.org" <shawnguo@kernel.org>,
        "s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
        "kernel@pengutronix.de" <kernel@pengutronix.de>,
        "festevam@gmail.com" <festevam@gmail.com>,
        dl-linux-imx <linux-imx@nxp.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Subject: RE: [PATCH 04/10] remoteproc: imx_rproc: make syscon optional
Thread-Topic: [PATCH 04/10] remoteproc: imx_rproc: make syscon optional
Thread-Index: AQHWYY4pPqmFoZ4ZzEWHmcUWZM64s6k+jjUAgAAzq9CAAT17AIAAaPAA
Date:   Thu, 20 Aug 2020 02:04:10 +0000
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> Subject: Re: [PATCH 04/10] remoteproc: imx_rproc: make syscon optional
>=20
> 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.
>=20
> In that case I assume the whole system gets rebooted, which puts the A7 i=
n a
> state where it can "attach" with the M4 again.

Yes. Whole system get rebooted.

>=20
> >
> > 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.
>=20
> And how does that notification work exactly?  Does rproc_report_crash() g=
et
> called somewhere in that process in order for the remoteproc core to atta=
ch
> 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.

Thanks,
Peng.

>=20
> Many thanks for the help,
> Mathieu
>=20
> >
> > Thanks,
> > Peng.
> >
> > >
> > > Thanks,
> > > Mathieu
> > >
> > > >
> > > > Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > > Signed-off-by: Peng Fan <peng.fan@nxp.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 =3D priv->dev;
> > > >  	int ret;
> > > >
> > > > +	if (!priv->regmap)
> > > > +		return -EOPNOTSUPP;
> > > > +
> > > >  	ret =3D 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 =3D priv->dev;
> > > >  	int ret;
> > > >
> > > > +	if (!priv->regmap)
> > > > +		return -EOPNOTSUPP;
> > > > +
> > > >  	ret =3D 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 =3D syscon_regmap_lookup_by_phandle(np, "syscon");
> > > >  	if (IS_ERR(regmap)) {
> > > >  		dev_err(dev, "failed to find syscon\n");
> > > > -		return PTR_ERR(regmap);
> > > > +		regmap =3D NULL;
> > > > +	} else {
> > > > +		regmap_attach_dev(dev, regmap, &config);
> > > >  	}
> > > > -	regmap_attach_dev(dev, regmap, &config);
> > > >
> > > >  	/* set some other name then imx */
> > > >  	rproc =3D rproc_alloc(dev, "imx-rproc", &imx_rproc_ops,
> > > > --
> > > > 2.16.4
> > > >