[PATCH v5 0/4] PCI: of: warn on bogus device_type property

[Alex Elder]

Add a check when adding a PCI device to ensure the device_type
property is (or is not) correctly defined when the device has
a non-null devicetree node pointer.

PCI has a well-defined bus and device discovery process.  The
PCI_DYNAMIC_OF_NODES Kconfig option allows PCI devices to *also*
have a devicetree node.  This enables certain things that are
not possible with PCI enumeration alone.

While working on a Qualcomm platform, I learned that some PCI
endpoint nodes were defined with device_type = "pci" properties.
Herve Codina pointed out that this was not correct.  Rob Herring
indicated that people seem to have trouble getting the PCI
devicetree nodes right, and asked whether we could warn if this
particular problem occurred.  During review, Herve Codina also
suggested that bridge nodes be checked to ensure they *do*
have the proper device_type property, and later, Sashiko suggested
that "pciex" (and "cardbus") also be accepted as valid bridge
device_type property values.

The first patch prevents a possible null pointer dereference that
Sashiko pointed out some time back.  This is the only patch that
has changed in this version.  (Last time I neglected to enable the
Kconfig option that ensured this go compiled, and it contained
two obvious compile errors.)

The second and third patches are simple cleanups.  The last adds
the new PCI devicetree node checks and warnings.

					-Alex

Between version 4 and version 5:
- Made a local variable (bufp) a pointer type in the first patch
- Eliminated an unused local variable (i) in the first patch

Version 4 is available here:
  https://lore.kernel.org/lkml/20260904134607.1856121-1-elder@xxxxxxxxxxxx/

Between version 3 and version 4:
- Insert a first patch that fixes a Sashiko-reported issue
- Drop the final "duplicate warning" patch from v3
- Include "pciex" as a valid PCI bridge device_type property value
- Add Herve's Reviewed-by tag on the last patch

Version 3 is available here:
  https://lore.kernel.org/lkml/20260901011338.1323243-1-elder@xxxxxxxxxxxx/

Between version 2 and version 3:
- Drop a patch that made a change only needed by a different series
- Switch a function header to use kernel-doc format
- Add a warning if a PCI bridge node has no device_type property
- Added a patch to remove a duplicate warning in the devicetree code

Version 2 is available here:
  https://lore.kernel.org/lkml/20260812172247.276554-1-elder@xxxxxxxxxxxx/

Between version 1 and version 2:
- Check the PCI devicetree node even when PCI_DYNAMIC_OF_NODES is
  not enabled

Version 1 is available here:
  https://lore.kernel.org/lkml/20260807194100.455599-1-elder@xxxxxxxxxxxx/

Alex Elder (4):
  PCI: of: avoid allocations in of_pci_prop_compatible()
  PCI: of: drop the reg_num argument to of_pci_set_address()
  PCI: of: don't zero flags in of_pci_get_addr_flags()
  PCI: of: introduce of_pci_verify_node()

 drivers/pci/bus.c         |  1 +
 drivers/pci/of.c          | 32 ++++++++++++++++++++++++++
 drivers/pci/of_property.c | 47 ++++++++++++++++++++++-----------------
 drivers/pci/pci.h         |  3 +++
 4 files changed, 63 insertions(+), 20 deletions(-)


base-commit: df2908090cda368b01ff43709f51890076c56157
-- 
2.53.0