PCI: dwc: ep: Clear MSI iATU mapping in dw_pcie_ep_cleanup()

The MSI iATU mapping is currently only cleared when the endpoint is
stopped via configfs or when the host updates the MSI address/size.
This avoids redundant iATU reconfiguration every time the endpoint
raises an MSI interrupt.

However, a fundamental reset triggered by PERST# assert/deassert
resets all iATU inbound/outbound registers without going through the
configfs stop path. If the host also retains the same MSI address/size
after PERST# deassert, the driver never clears the stale MSI iATU
mapping. It then continues using this stale mapping to raise the MSI
interrupts, which can cause IOMMU faults and MSI failures on the host.

Fix this by clearing the MSI iATU mapping inside dw_pcie_ep_cleanup(),
which is already called as part of the PERST# assert/deassert sequence.
This unmaps the MSI iATU region and sets the msi_iatu_mapped flag to
false, ensuring that dw_pcie_ep_raise_msi_irq() performs a fresh iATU
mapping on its next invocation, regardless of whether the host changed
the MSI address/size.

Fixes: 8719c64e76bf ("PCI: dwc: ep: Cache MSI outbound iATU mapping")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Link: https://patch.msgid.link/20260729-pci-port-reset-v9-1-53570b92064d@oss.qualcomm.com

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 7d2794945704..31402ae218c7 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -1153,6 +1153,11 @@ void dw_pcie_ep_cleanup(struct dw_pcie_ep *ep)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
+	if (ep->msi_iatu_mapped) {
+		dw_pcie_ep_unmap_addr(ep->epc, 0, 0, ep->msi_mem_phys);
+		ep->msi_iatu_mapped = false;
+	}
+
 	dwc_pcie_debugfs_deinit(pci);
 	dw_pcie_edma_remove(pci);
 }