[PATCH 2/2] PCI: of: Attach created of_node to existing device

[PATCH 2/2] PCI: of: Attach created of_node to existing device

[Herve Codina]

The commit 407d1a51921e ("PCI: Create device tree node for bridge")
creates of_node for PCI devices.
During the insertion handling of these new DT nodes done by of_platform,
new devices (struct device) are created.
For each PCI devices a struct device is already present (created and
handled by the PCI core).
Having a second struct device to represent the exact same PCI device is
not correct.

On the of_node creation, tell the of_platform that there is no need to
create a device for this node (OF_POPULATED flag), link this newly
created of_node to the already present device and tell fwnode that the
device attached to this of_node is ready (fwnode_dev_initialized()).

With this fix, the of_node are available in the sysfs device tree:
/sys/devices/platform/soc/d0070000.pcie/
+ of_node -> .../devicetree/base/soc/pcie@d0070000
+ pci0000:00
  + 0000:00:00.0
    + of_node -> .../devicetree/base/soc/pcie@d0070000/pci@0,0
    + 0000:01:00.0
      + of_node -> .../devicetree/base/soc/pcie@d0070000/pci@0,0/dev@0,0

On the of_node removal, revert the operations.

Fixes: 407d1a51921e ("PCI: Create device tree node for bridge")
Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
---
 drivers/pci/of.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 51e3dd0ea5ab..5afd2731e876 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -615,7 +615,8 @@ void of_pci_remove_node(struct pci_dev *pdev)
 	np = pci_device_to_OF_node(pdev);
 	if (!np || !of_node_check_flag(np, OF_DYNAMIC))
 		return;
-	pdev->dev.of_node = NULL;
+
+	device_remove_of_node(&pdev->dev);
 
 	of_changeset_revert(np->data);
 	of_changeset_destroy(np->data);
@@ -668,12 +669,22 @@ void of_pci_make_dev_node(struct pci_dev *pdev)
 	if (ret)
 		goto out_free_node;
 
+	/*
+	 * This of_node will be added to an existing device.
+	 * Avoid any device creation and use the existing device
+	 */
+	of_node_set_flag(np, OF_POPULATED);
+	np->fwnode.dev = &pdev->dev;
+	fwnode_dev_initialized(&np->fwnode, true);
+
 	ret = of_changeset_apply(cset);
 	if (ret)
 		goto out_free_node;
 
 	np->data = cset;
-	pdev->dev.of_node = np;
+
+	/* Add the of_node to the existing device */
+	device_add_of_node(&pdev->dev, np);
 	kfree(name);
 
 	return;
-- 
2.42.0

Re: [PATCH 2/2] PCI: of: Attach created of_node to existing device

[Greg Kroah-Hartman]

On Thu, Nov 30, 2023 at 04:24:04PM +0100, Herve Codina wrote:
> The commit 407d1a51921e ("PCI: Create device tree node for bridge")
> creates of_node for PCI devices.
> During the insertion handling of these new DT nodes done by of_platform,
> new devices (struct device) are created.
> For each PCI devices a struct device is already present (created and
> handled by the PCI core).
> Having a second struct device to represent the exact same PCI device is
> not correct.
> 
> On the of_node creation, tell the of_platform that there is no need to
> create a device for this node (OF_POPULATED flag), link this newly
> created of_node to the already present device and tell fwnode that the
> device attached to this of_node is ready (fwnode_dev_initialized()).
> 
> With this fix, the of_node are available in the sysfs device tree:
> /sys/devices/platform/soc/d0070000.pcie/
> + of_node -> .../devicetree/base/soc/pcie@d0070000
> + pci0000:00
>   + 0000:00:00.0
>     + of_node -> .../devicetree/base/soc/pcie@d0070000/pci@0,0
>     + 0000:01:00.0
>       + of_node -> .../devicetree/base/soc/pcie@d0070000/pci@0,0/dev@0,0
> 
> On the of_node removal, revert the operations.
> 
> Fixes: 407d1a51921e ("PCI: Create device tree node for bridge")
> Cc: stable@vger.kernel.org

How can this be cc: stable when the api it relies on is not?

confused,

greg k-h

Re: [PATCH 2/2] PCI: of: Attach created of_node to existing device

[Herve Codina]

Hi Greg,

On Thu, 30 Nov 2023 16:18:58 +0000
Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> On Thu, Nov 30, 2023 at 04:24:04PM +0100, Herve Codina wrote:
> > The commit 407d1a51921e ("PCI: Create device tree node for bridge")
> > creates of_node for PCI devices.
> > During the insertion handling of these new DT nodes done by of_platform,
> > new devices (struct device) are created.
> > For each PCI devices a struct device is already present (created and
> > handled by the PCI core).
> > Having a second struct device to represent the exact same PCI device is
> > not correct.
> > 
> > On the of_node creation, tell the of_platform that there is no need to
> > create a device for this node (OF_POPULATED flag), link this newly
> > created of_node to the already present device and tell fwnode that the
> > device attached to this of_node is ready (fwnode_dev_initialized()).
> > 
> > With this fix, the of_node are available in the sysfs device tree:
> > /sys/devices/platform/soc/d0070000.pcie/
> > + of_node -> .../devicetree/base/soc/pcie@d0070000
> > + pci0000:00
> >   + 0000:00:00.0
> >     + of_node -> .../devicetree/base/soc/pcie@d0070000/pci@0,0
> >     + 0000:01:00.0
> >       + of_node -> .../devicetree/base/soc/pcie@d0070000/pci@0,0/dev@0,0
> > 
> > On the of_node removal, revert the operations.
> > 
> > Fixes: 407d1a51921e ("PCI: Create device tree node for bridge")
> > Cc: stable@vger.kernel.org  
> 
> How can this be cc: stable when the api it relies on is not?
> 
> confused,

My bad, I will add cc: stable in the other patch needed.

Sorry about that.
Hervé

-- 
Hervé Codina, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com