[PATCH v6 0/3] PCI: qcom: Implement shutdown() to avoid SMMU/NoC errors on reboot

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

During system shutdown/reboot, power/clocks to the PCIe controller get
removed regardless of link state. If the link is still up when that
happens, it can trigger SMMU or NoC errors.

This series adds a shutdown() callback to the Qualcomm PCIe host driver
that forces the link into L2/D3cold before shutdown proceeds, reusing
the existing suspend_noirq() path.

Patch 1 fixes pci_host_common_d3cold_possible()'s underlying bus walk,
which aborts as soon as it finds a device outside D3hot and can
therefore miss a later PME-capable device -- something that becomes
common once patch 3 starts forcing D3cold entry during shutdown while
endpoints may still be in D0.

Patch 2 adds a force parameter to  dw_pcie_suspend_noirq() so that callers can
set to make dw_pcie_suspend_noirq() force L2 entry during shutdown/
reboot, skipping the D3cold capability check that can otherwise leave
the link up if any endpoint hasn't suspended yet.

Patch 3 adds qcom_pcie_shutdown() and wires it up as .shutdown.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
---
Changes in v6:
- remove return 0 in d3cold_possible() (konrad)
- use force as a paramter instead of the element (Mani)
- couple of nits (Konrad)
- call pm_runtime calls for firmware managed one also as we are enabling
  pm_runtime_enable and get for that also.
- Link to v5: https://patch.msgid.link/20260905-shutdown-v5-0-f0c6bafa1d4f@oss.qualcomm.com

Changes in v5:
- use a flag/parameter Instead of poking the system states (Mani)
- Fix pme_wakeup issue by walking through entire bus (Sashiko)
- Fix Irq free issue by using dwc free msi API (Sashiko)
- Link to v4: https://patch.msgid.link/20260826-shutdown-v4-0-eb5fe9d454ae@oss.qualcomm.com

Changes in v4:
- removed goto d3cold, (Konrad & Sashiko for PME error)
- Disabling MSI IRQ's (Sashiko)
- Link to v3: https://patch.msgid.link/20260824-shutdown-v3-0-81c14bb7a1af@oss.qualcomm.com

Changes in v3:
- Added null point check and use pm_runtime_put_sync (Sashiko).
- Link to v2: https://patch.msgid.link/20260822-shutdown-v2-0-520a68f1b4a5@oss.qualcomm.com

Changes in v2:
1) don't remove the endpoint pci dev's only keep link in D3cold.
Link to v1: https://lore.kernel.org/all/20250401-shutdown-v1-1-f699859403ae@oss.qualcomm.com/

---
Krishna Chaitanya Chundru (2):
      PCI: host-common: Fix early bus-walk exit in d3cold_possible()
      PCI: dwc: Force L2 link entry on shutdown/reboot without D3cold check

Manivannan Sadhasivam (1):
      PCI: qcom: Implement shutdown() callback

 drivers/pci/controller/dwc/pci-imx6.c             |  2 +-
 drivers/pci/controller/dwc/pci-layerscape.c       |  2 +-
 drivers/pci/controller/dwc/pcie-designware-host.c |  7 +++--
 drivers/pci/controller/dwc/pcie-designware.h      |  4 +--
 drivers/pci/controller/dwc/pcie-eswin.c           |  2 +-
 drivers/pci/controller/dwc/pcie-nxp-s32g.c        |  2 +-
 drivers/pci/controller/dwc/pcie-qcom.c            | 37 ++++++++++++++++++++++-
 drivers/pci/controller/dwc/pcie-stm32.c           |  2 +-
 drivers/pci/controller/dwc/pcie-ultrarisc.c       |  2 +-
 drivers/pci/controller/pci-host-common.c          | 13 +++-----
 10 files changed, 52 insertions(+), 21 deletions(-)
---
base-commit: 12f8e3e3eef4a662b622cf12f00981f64c276307
change-id: 20260822-shutdown-fe8139dff2b7

Best regards,
--  
Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>