When we scan an empty slot the PHB gets an Unsupported Request from the
downstream bridge when there's no device present at that BDFN. Some older
PHBs (p7-IOC) don't allow further config space accesses while the PE is
frozen, so clear it here without bothering with the diagnostic log.
Signed-off-by: Oliver O'Halloran <ooh...@gmail.com>
---
arch/powerpc/platforms/powernv/pci.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/arch/powerpc/platforms/powernv/pci.c
b/arch/powerpc/platforms/powernv/pci.c
index 36eea4bb514c..5b1f4677cdce 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -642,6 +642,19 @@ static void pnv_pci_config_check_eeh(struct pnv_phb *phb,
u16 bdfn)
if (fstate == OPAL_EEH_STOPPED_MMIO_FREEZE ||
fstate == OPAL_EEH_STOPPED_DMA_FREEZE ||
fstate == OPAL_EEH_STOPPED_MMIO_DMA_FREEZE) {
+
+ /*
+ * Scanning an empty slot will result in a freeze on the
reserved PE.
+ *
+ * Some old and bad PHBs block config space access to frozen
PEs in
+ * addition to MMIOs, so unfreeze it here.
+ */
+ if (pe_no == phb->ioda.reserved_pe_idx) {
+ phb->unfreeze_pe(phb, phb->ioda.reserved_pe_idx,
+ OPAL_EEH_ACTION_CLEAR_FREEZE_ALL);
+ return;
+ }
+
/*
* If PHB supports compound PE, freeze it for
* consistency.
--
2.21.0
