Re: [PATCH v3 3/4] PCI: of: introduce of_pci_verify_node()

[Herve Codina <herve.codina@bootlin.com>]

Hi Alex,

On Mon, 31 Aug 2026 20:13:36 -0500
Alex Elder <elder@riscstar.com> wrote:

> Commit 407d1a51921e9 ("PCI: Create device tree node for bridge") linked
> the PCI enumeration process together with devicetree, creating a devicetree
> node for discovered PCI bridges.  Its successor commit ae9813db1dc5a ("PCI:
> Add quirks to generate device tree node for Xilinx Alveo U50") shows how
> to use a PCI final fixup quirk to also create a devicetree node for a
> non-bridge PCI device.  These changes allowed devicetree overlays to
> describe components downstream of a PCI device, by providing a place to
> attach the overlay.
> 
> Note that the dynamic devicetree node is only created if the device didn't
> already have an assigned node.
> 
> Later, commit aa7b4bbcb3a1d ("arm64: dts: qcom: qcs6490-rb3gen2: Add
> TC9563 PCIe switch node") *pre-defined* devicetree nodes to represent the
> PCI device nodes that would (also) be discovered via the PCI enumeration
> process.  The devicetree node in this case is created with the content
> from the DTS file.  So when a (host) bridge is done being initialized
> during PCI enumeration, no node is dynamically created (the commits
> mentioned above do not apply).
> 
> Ideally, any pre-defined PCI devicetree node would contain exactly the
> same information as whatever the dynamic creation process would produce
> (though it could include more).
> 
> However that is not the case for the pre-defined Qualcomm RB3gen2 nodes.
> And in particular, the endpoint (function) nodes include this property:
> 
>     device_type = "pci";
> 
> This is simply wrong; that property is meant only for bridge nodes.
> 
> Rob Herring requested that a runtime check to be added to spot this
> specific error, only for non-bridge PCI devices.  Herve Codina further
> suggested we ensure that bridge PCI devices *do* define the device_type
> property, with value "pci".
> 
> Signed-off-by: Alex Elder <elder@riscstar.com>
> ---
> v3: - Switch a function header to use kernel-doc format
>     - Add a warning if a PCI bridge node has no device_type property
> 
>  drivers/pci/bus.c |  1 +
>  drivers/pci/of.c  | 31 +++++++++++++++++++++++++++++++
>  drivers/pci/pci.h |  3 +++
>  3 files changed, 35 insertions(+)
> 

LGTM.

Reviewed-by: Herve Codina <herve.codina@bootlin.com>

Best regards,
Hervé