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[PATCH v4 1/6] driver core: Introduce device_{add,remove}_of_node()

Herve Codina posted 6 patches 1 year, 2 months ago
There is a newer version of this series
[PATCH v4 1/6] driver core: Introduce device_{add,remove}_of_node()
Posted by Herve Codina 1 year, 2 months ago 
An of_node can be set to a device using device_set_node().
This function cannot prevent any of_node and/or fwnode overwrites.

When adding an of_node on an already present device, the following
operations need to be done:
- Attach the of_node if no of_node were already attached
- Attach the of_node as a fwnode if no fwnode were already attached

This is the purpose of device_add_of_node().
device_remove_of_node() reverts the operations done by
device_add_of_node().

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
---
 drivers/base/core.c    | 52 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/device.h |  2 ++
 2 files changed, 54 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 8b056306f04e..3953c5ab7316 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -5216,6 +5216,58 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
 }
 EXPORT_SYMBOL_GPL(set_secondary_fwnode);
 
+/**
+ * device_remove_of_node - Remove an of_node from a device
+ * @dev: device whose device-tree node is being removed
+ */
+void device_remove_of_node(struct device *dev)
+{
+	dev = get_device(dev);
+	if (!dev)
+		return;
+
+	if (!dev->of_node)
+		goto end;
+
+	if (dev->fwnode == of_fwnode_handle(dev->of_node))
+		dev->fwnode = NULL;
+
+	of_node_put(dev->of_node);
+	dev->of_node = NULL;
+
+end:
+	put_device(dev);
+}
+EXPORT_SYMBOL_GPL(device_remove_of_node);
+
+/**
+ * device_add_of_node - Add an of_node to an existing device
+ * @dev: device whose device-tree node is being added
+ * @of_node: of_node to add
+ */
+void device_add_of_node(struct device *dev, struct device_node *of_node)
+{
+	if (!of_node)
+		return;
+
+	dev = get_device(dev);
+	if (!dev)
+		return;
+
+	if (WARN(dev->of_node, "%s: Cannot replace node %pOF with %pOF\n",
+		 dev_name(dev), dev->of_node, of_node))
+		goto end;
+
+	dev->of_node = of_node_get(of_node);
+
+	if (!dev->fwnode)
+		dev->fwnode = of_fwnode_handle(of_node);
+
+end:
+	put_device(dev);
+}
+EXPORT_SYMBOL_GPL(device_add_of_node);
+
 /**
  * device_set_of_node_from_dev - reuse device-tree node of another device
  * @dev: device whose device-tree node is being set
diff --git a/include/linux/device.h b/include/linux/device.h
index 667cb6db9019..ef4c0f3c41cd 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1149,6 +1149,8 @@ int device_online(struct device *dev);
 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
 void device_set_node(struct device *dev, struct fwnode_handle *fwnode);
+void device_add_of_node(struct device *dev, struct device_node *of_node);
+void device_remove_of_node(struct device *dev);
 void device_set_of_node_from_dev(struct device *dev, const struct device *dev2);
 
 static inline struct device_node *dev_of_node(struct device *dev)
-- 
2.47.0
Re: [PATCH v4 1/6] driver core: Introduce device_{add,remove}_of_node()
Posted by Bjorn Helgaas 1 year, 2 months ago 
[cc->to Greg, Rafael]

On Mon, Dec 02, 2024 at 02:15:13PM +0100, Herve Codina wrote:
> An of_node can be set to a device using device_set_node().
> This function cannot prevent any of_node and/or fwnode overwrites.
> 
> When adding an of_node on an already present device, the following
> operations need to be done:
> - Attach the of_node if no of_node were already attached
> - Attach the of_node as a fwnode if no fwnode were already attached
> 
> This is the purpose of device_add_of_node().
> device_remove_of_node() reverts the operations done by
> device_add_of_node().
> 
> Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> ---
>  drivers/base/core.c    | 52 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/device.h |  2 ++

I suppose this series would go via the PCI tree since the bulk of the
changes are there.  If so, I would look for an ack from the driver
core folks (Greg, Rafael).

>  2 files changed, 54 insertions(+)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 8b056306f04e..3953c5ab7316 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -5216,6 +5216,58 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
>  }
>  EXPORT_SYMBOL_GPL(set_secondary_fwnode);
>  
> +/**
> + * device_remove_of_node - Remove an of_node from a device
> + * @dev: device whose device-tree node is being removed
> + */
> +void device_remove_of_node(struct device *dev)
> +{
> +	dev = get_device(dev);
> +	if (!dev)
> +		return;
> +
> +	if (!dev->of_node)
> +		goto end;
> +
> +	if (dev->fwnode == of_fwnode_handle(dev->of_node))
> +		dev->fwnode = NULL;
> +
> +	of_node_put(dev->of_node);
> +	dev->of_node = NULL;
> +
> +end:
> +	put_device(dev);
> +}
> +EXPORT_SYMBOL_GPL(device_remove_of_node);
> +
> +/**
> + * device_add_of_node - Add an of_node to an existing device
> + * @dev: device whose device-tree node is being added
> + * @of_node: of_node to add
> + */
> +void device_add_of_node(struct device *dev, struct device_node *of_node)
> +{
> +	if (!of_node)
> +		return;
> +
> +	dev = get_device(dev);
> +	if (!dev)
> +		return;
> +
> +	if (WARN(dev->of_node, "%s: Cannot replace node %pOF with %pOF\n",
> +		 dev_name(dev), dev->of_node, of_node))
> +		goto end;
> +
> +	dev->of_node = of_node_get(of_node);
> +
> +	if (!dev->fwnode)
> +		dev->fwnode = of_fwnode_handle(of_node);
> +
> +end:
> +	put_device(dev);
> +}
> +EXPORT_SYMBOL_GPL(device_add_of_node);
> +
>  /**
>   * device_set_of_node_from_dev - reuse device-tree node of another device
>   * @dev: device whose device-tree node is being set
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 667cb6db9019..ef4c0f3c41cd 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -1149,6 +1149,8 @@ int device_online(struct device *dev);
>  void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
>  void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
>  void device_set_node(struct device *dev, struct fwnode_handle *fwnode);
> +void device_add_of_node(struct device *dev, struct device_node *of_node);
> +void device_remove_of_node(struct device *dev);
>  void device_set_of_node_from_dev(struct device *dev, const struct device *dev2);
>  
>  static inline struct device_node *dev_of_node(struct device *dev)
> -- 
> 2.47.0
>
Re: [PATCH v4 1/6] driver core: Introduce device_{add,remove}_of_node()
Posted by Greg Kroah-Hartman 1 year, 2 months ago 
On Wed, Dec 04, 2024 at 03:38:25PM -0600, Bjorn Helgaas wrote:
> [cc->to Greg, Rafael]
> 
> On Mon, Dec 02, 2024 at 02:15:13PM +0100, Herve Codina wrote:
> > An of_node can be set to a device using device_set_node().
> > This function cannot prevent any of_node and/or fwnode overwrites.
> > 
> > When adding an of_node on an already present device, the following
> > operations need to be done:
> > - Attach the of_node if no of_node were already attached
> > - Attach the of_node as a fwnode if no fwnode were already attached
> > 
> > This is the purpose of device_add_of_node().
> > device_remove_of_node() reverts the operations done by
> > device_add_of_node().
> > 
> > Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> > ---
> >  drivers/base/core.c    | 52 ++++++++++++++++++++++++++++++++++++++++++
> >  include/linux/device.h |  2 ++
> 
> I suppose this series would go via the PCI tree since the bulk of the
> changes are there.  If so, I would look for an ack from the driver
> core folks (Greg, Rafael).
> 
> >  2 files changed, 54 insertions(+)
> > 
> > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > index 8b056306f04e..3953c5ab7316 100644
> > --- a/drivers/base/core.c
> > +++ b/drivers/base/core.c
> > @@ -5216,6 +5216,58 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
> >  }
> >  EXPORT_SYMBOL_GPL(set_secondary_fwnode);
> >  
> > +/**
> > + * device_remove_of_node - Remove an of_node from a device
> > + * @dev: device whose device-tree node is being removed
> > + */
> > +void device_remove_of_node(struct device *dev)
> > +{
> > +	dev = get_device(dev);
> > +	if (!dev)
> > +		return;
> > +
> > +	if (!dev->of_node)
> > +		goto end;
> > +
> > +	if (dev->fwnode == of_fwnode_handle(dev->of_node))
> > +		dev->fwnode = NULL;
> > +
> > +	of_node_put(dev->of_node);
> > +	dev->of_node = NULL;
> > +
> > +end:
> > +	put_device(dev);
> > +}
> > +EXPORT_SYMBOL_GPL(device_remove_of_node);
> > +
> > +/**
> > + * device_add_of_node - Add an of_node to an existing device
> > + * @dev: device whose device-tree node is being added
> > + * @of_node: of_node to add
> > + */
> > +void device_add_of_node(struct device *dev, struct device_node *of_node)
> > +{
> > +	if (!of_node)
> > +		return;
> > +
> > +	dev = get_device(dev);
> > +	if (!dev)
> > +		return;
> > +
> > +	if (WARN(dev->of_node, "%s: Cannot replace node %pOF with %pOF\n",
> > +		 dev_name(dev), dev->of_node, of_node))
> > +		goto end;

Please do not reboot machines that have panic-on-warn for something that
you can properly handle and recover from (like this.)  Just print out a
message and continue on, or better yet, return an error if this didn't
work properly.

thanks,

greg k-h
Re: [PATCH v4 1/6] driver core: Introduce device_{add,remove}_of_node()
Posted by Herve Codina 1 year, 2 months ago 
Hi Greg,

On Thu, 5 Dec 2024 08:00:44 +0100
Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> On Wed, Dec 04, 2024 at 03:38:25PM -0600, Bjorn Helgaas wrote:
> > [cc->to Greg, Rafael]
> > 
> > On Mon, Dec 02, 2024 at 02:15:13PM +0100, Herve Codina wrote:  
> > > An of_node can be set to a device using device_set_node().
> > > This function cannot prevent any of_node and/or fwnode overwrites.
> > > 
> > > When adding an of_node on an already present device, the following
> > > operations need to be done:
> > > - Attach the of_node if no of_node were already attached
> > > - Attach the of_node as a fwnode if no fwnode were already attached
> > > 
> > > This is the purpose of device_add_of_node().
> > > device_remove_of_node() reverts the operations done by
> > > device_add_of_node().
> > > 
> > > Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> > > ---
> > >  drivers/base/core.c    | 52 ++++++++++++++++++++++++++++++++++++++++++
> > >  include/linux/device.h |  2 ++  
> > 
> > I suppose this series would go via the PCI tree since the bulk of the
> > changes are there.  If so, I would look for an ack from the driver
> > core folks (Greg, Rafael).
> >   
> > >  2 files changed, 54 insertions(+)
> > > 
> > > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > > index 8b056306f04e..3953c5ab7316 100644
> > > --- a/drivers/base/core.c
> > > +++ b/drivers/base/core.c
> > > @@ -5216,6 +5216,58 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
> > >  }
> > >  EXPORT_SYMBOL_GPL(set_secondary_fwnode);
> > >  
> > > +/**
> > > + * device_remove_of_node - Remove an of_node from a device
> > > + * @dev: device whose device-tree node is being removed
> > > + */
> > > +void device_remove_of_node(struct device *dev)
> > > +{
> > > +	dev = get_device(dev);
> > > +	if (!dev)
> > > +		return;
> > > +
> > > +	if (!dev->of_node)
> > > +		goto end;
> > > +
> > > +	if (dev->fwnode == of_fwnode_handle(dev->of_node))
> > > +		dev->fwnode = NULL;
> > > +
> > > +	of_node_put(dev->of_node);
> > > +	dev->of_node = NULL;
> > > +
> > > +end:
> > > +	put_device(dev);
> > > +}
> > > +EXPORT_SYMBOL_GPL(device_remove_of_node);
> > > +
> > > +/**
> > > + * device_add_of_node - Add an of_node to an existing device
> > > + * @dev: device whose device-tree node is being added
> > > + * @of_node: of_node to add
> > > + */
> > > +void device_add_of_node(struct device *dev, struct device_node *of_node)
> > > +{
> > > +	if (!of_node)
> > > +		return;
> > > +
> > > +	dev = get_device(dev);
> > > +	if (!dev)
> > > +		return;
> > > +
> > > +	if (WARN(dev->of_node, "%s: Cannot replace node %pOF with %pOF\n",
> > > +		 dev_name(dev), dev->of_node, of_node))
> > > +		goto end;  
> 
> Please do not reboot machines that have panic-on-warn for something that
> you can properly handle and recover from (like this.)  Just print out a
> message and continue on, or better yet, return an error if this didn't
> work properly.
> 

I will change to dev_warn() in the next iteration.

Thanks for pointing this.
Best regards,
Hervé

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