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From: Saravana Kannan <saravanak@google.com>
Date: Mon, 8 Apr 2024 22:13:01 -0700
Message-ID: <CAGETcx8j50dpovO-Mj0MjpYcw+n6T9ei6mo8tm7BVkcjfy_VVQ@mail.gmail.com>
Subject: Re: [RFC PATCH v1 2/2] of: dynamic: Fix probing of overlay devices
To: Herve Codina <herve.codina@bootlin.com>, Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Rob Herring <robh@kernel.org>, kernel-team@android.com, linux-kernel@vger.kernel.org, 
	imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, 
	linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, 
	linux-spi@vger.kernel.org, linux-acpi@vger.kernel.org
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On Mon, Apr 8, 2024 at 6:40=E2=80=AFPM Saravana Kannan <saravanak@google.co=
m> wrote:
>
> On Mon, Apr 8, 2024 at 4:13=E2=80=AFPM Saravana Kannan <saravanak@google.=
com> wrote:
> >
> > Get fw_devlink to work well with overlay devices.
> >
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > ---
> >  drivers/base/core.c    | 10 ++++++++++
> >  drivers/of/dynamic.c   |  8 ++++++++
> >  include/linux/fwnode.h |  2 ++
> >  3 files changed, 20 insertions(+)
> >
> > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > index 5f4e03336e68..d856f9c5d601 100644
> > --- a/drivers/base/core.c
> > +++ b/drivers/base/core.c
> > @@ -237,6 +237,16 @@ static void __fw_devlink_pickup_dangling_consumers=
(struct fwnode_handle *fwnode,
> >                 __fw_devlink_pickup_dangling_consumers(child, new_sup);
> >  }
> >
> > +
> > +void fw_devlink_pickup_dangling_consumers(struct fwnode_handle *child,
> > +                                                struct fwnode_handle *=
parent)
> > +{
> > +       mutex_lock(&fwnode_link_lock);
> > +       __fw_devlink_pickup_dangling_consumers(child, parent);
> > +       __fw_devlink_link_to_consumers(parent->dev);
> > +       mutex_unlock(&fwnode_link_lock);
> > +}
> > +
> >  static DEFINE_MUTEX(device_links_lock);
> >  DEFINE_STATIC_SRCU(device_links_srcu);
> >
> > diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
> > index 19a1a38554f2..0a936f46820e 100644
> > --- a/drivers/of/dynamic.c
> > +++ b/drivers/of/dynamic.c
> > @@ -237,6 +237,7 @@ static void __of_attach_node(struct device_node *np=
)
> >  int of_attach_node(struct device_node *np)
> >  {
> >         struct of_reconfig_data rd;
> > +       struct fwnode_handle *fwnode, *parent;
> >
> >         memset(&rd, 0, sizeof(rd));
> >         rd.dn =3D np;
> > @@ -246,6 +247,13 @@ int of_attach_node(struct device_node *np)
> >         mutex_unlock(&of_mutex);
> >
> >         of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
> > +       fwnode =3D of_fwnode_handle(np);
> > +       fwnode_for_each_parent_node(fwnode, parent)
> > +               if (parent->dev) {
> > +                       fw_devlink_pickup_dangling_consumers(fwnode, pa=
rent);
> > +                       fwnode_handle_put(parent);
> > +                       break;
> > +               }
>
> I'm clearly calling this in the wrong location. Please move this logic
> to __of_changeset_entry_notify() and for the case
> OF_RECONFIG_ATTACH_NODE. Haven't fully thought through the DETACH
> case, but it should work correctly for that case too. If not, I'll
> take care of that next.
>

I'll send out a RFC v2 with the code fixed up in a few minutes.

> -Saravana
>
> >
> >         return 0;
> >  }
> > diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
> > index 0d79070c5a70..4b3f697a90e8 100644
> > --- a/include/linux/fwnode.h
> > +++ b/include/linux/fwnode.h
> > @@ -220,6 +220,8 @@ int fwnode_link_add(struct fwnode_handle *con, stru=
ct fwnode_handle *sup,
> >                     u8 flags);
> >  void fwnode_links_purge(struct fwnode_handle *fwnode);
> >  void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode);
> > +void fw_devlink_pickup_dangling_consumers(struct fwnode_handle *child,
> > +                                         struct fwnode_handle *parent)=
;
> >  bool fw_devlink_is_strict(void);
> >
> >  #endif
> > --
> > 2.44.0.478.gd926399ef9-goog
> >