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

Hi Alex,

On Mon, 31 Aug 2026 20:13:36 -0500
Alex Elder [off-list ref] 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 <redacted>
---
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