Subject: Re: [PATCH v5 3/4] remoteproc: imx_dsp_rproc: Add remoteproc driver for DSP on i.MX

From: Mathieu Poirier <[email-masked]>
Date: Fri, 8 Oct 2021 09:42:47 -0600

On Fri, Oct 08, 2021 at 09:53:18AM +0800, Shengjiu Wang wrote:
> Hi Mathieu
> 
> On Thu, Oct 7, 2021 at 12:25 AM Mathieu Poirier
> <[email-masked]> wrote:
> >
> > Hi Shengjiu,
> >
> > This pachset doesn't apply to rproc-next, which is now located here[1].  The
> > change is in linux-next but not in mainline yet.
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux.git/log/?h=rproc-next
> 
> Ok, I will double check it and fix it.
> 
> >
> > On Sun, Sep 26, 2021 at 11:07:09AM +0800, Shengjiu Wang wrote:
> > > Provide a basic driver to control DSP processor found on NXP i.MX8QM,
> > > i.MX8QXP, i.MX8MP and i.MX8ULP.
> > >
> > > Currently it is able to resolve addresses between DSP and main CPU,
> > > start and stop the processor, suspend and resume.
> > >
> > > The communication between DSP and main CPU is based on mailbox, there
> > > are three mailbox channels (tx, rx, rxdb).
> > >
> > > This driver was tested on NXP i.MX8QM, i.MX8QXP, i.MX8MP and i.MX8ULP.
> > >
> > > Signed-off-by: Shengjiu Wang <[email-masked]>
> > > ---
> > >  drivers/remoteproc/Kconfig         |   11 +
> > >  drivers/remoteproc/Makefile        |    1 +
> > >  drivers/remoteproc/imx_dsp_rproc.c | 1206 ++++++++++++++++++++++++++++
> > >  3 files changed, 1218 insertions(+)
> > >  create mode 100644 drivers/remoteproc/imx_dsp_rproc.c
> > >
> >
> > [...]
> >
> > > +
> > > +/**
> > > + * imx_dsp_attach_pm_domains() - attach the power domains
> > > + * @priv: private data pointer
> > > + *
> > > + * On i.MX8QM and i.MX8QXP there is multiple power domains
> > > + * required, so need to link them.
> > > + */
> > > +static int imx_dsp_attach_pm_domains(struct imx_dsp_rproc *priv)
> > > +{
> > > +     struct device *dev = priv->rproc->dev.parent;
> > > +     int ret, i;
> > > +
> > > +     priv->num_domains = of_count_phandle_with_args(dev->of_node,
> > > +                                                    "power-domains",
> > > +                                                    "#power-domain-cells");
> > > +
> > > +     /* If only one domain, then no need to link the device */
> > > +     if (priv->num_domains <= 1)
> > > +             return 0;
> > > +
> > > +     priv->pd_dev = devm_kmalloc_array(dev, priv->num_domains,
> > > +                                       sizeof(*priv->pd_dev),
> > > +                                       GFP_KERNEL);
> > > +     if (!priv->pd_dev)
> > > +             return -ENOMEM;
> > > +
> > > +     priv->pd_dev_link = devm_kmalloc_array(dev, priv->num_domains,
> > > +                                            sizeof(*priv->pd_dev_link),
> > > +                                            GFP_KERNEL);
> > > +     if (!priv->pd_dev_link)
> > > +             return -ENOMEM;
> > > +
> > > +     for (i = 0; i < priv->num_domains; i++) {
> > > +             priv->pd_dev[i] = dev_pm_domain_attach_by_id(dev, i);
> > > +             if (IS_ERR(priv->pd_dev[i])) {
> > > +                     ret = PTR_ERR(priv->pd_dev[i]);
> > > +                     goto detach_pm;
> > > +             }
> >
> > I have pointed a problem with the error handling in the above during the
> > previous review and it was not addressed.
> 
> I have considered your comments.  Actually when
> dev_pm_domain_attach_by_id() return NULL, the device_link_add()
> will break, I have added comments below, so above error handling
> for dev_pm_domain_attach_by_id() is enough.

I would have used IS_ERR_OR_NULL() so that potential code inserted between the
two function doesn't automatically assume priv->pd_dev[i] is valid.  But what
you have here will work.

Reviewed-by: Mathieu Poirier <[email-masked]>
 
> Best regards
> Wang Shengjiu
> >
> > > +
> > > +             /*
> > > +              * device_link_add will check priv->pd_dev[i], if it is
> > > +              * NULL, then will break.
> > > +              */
> > > +             priv->pd_dev_link[i] = device_link_add(dev,
> > > +                                                    priv->pd_dev[i],
> > > +                                                    DL_FLAG_STATELESS |
> > > +                                                    DL_FLAG_PM_RUNTIME);
> > > +             if (!priv->pd_dev_link[i]) {
> > > +                     dev_pm_domain_detach(priv->pd_dev[i], false);
> > > +                     ret = -EINVAL;
> > > +                     goto detach_pm;
> > > +             }
> > > +     }
> > > +
> > > +     return 0;
> > > +
> > > +detach_pm:
> > > +     while (--i >= 0) {
> > > +             device_link_del(priv->pd_dev_link[i]);
> > > +             dev_pm_domain_detach(priv->pd_dev[i], false);
> > > +     }
> > > +
> > > +     return ret;
> > > +}
> > > +

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