powerpc/eeh: Enable EEH check for config access

The patch enables EEH check and let EEH core to process the EEH
errors for PowerNV platform while accessing config space. Originally,
the implementation already had mechanism to check EEH errors and
tried to recover from them. However, we never let EEH core to handle
the EEH errors.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/pci.c

@@ -33,6 +33,8 @@
 #include <asm/iommu.h>
 #include <asm/tce.h>
 #include <asm/firmware.h>
+#include <asm/eeh_event.h>
+#include <asm/eeh.h>
 
 #include "powernv.h"
 #include "pci.h"
@@ -260,6 +262,10 @@ static int pnv_pci_read_config(struct pci_bus *bus,
 {
 	struct pci_controller *hose = pci_bus_to_host(bus);
 	struct pnv_phb *phb = hose->private_data;
+#ifdef CONFIG_EEH
+	struct device_node *busdn, *dn;
+	struct eeh_pe *phb_pe = NULL;
+#endif
 	u32 bdfn = (((uint64_t)bus->number) << 8) | devfn;
 	s64 rc;
 
@@ -292,8 +298,34 @@ static int pnv_pci_read_config(struct pci_bus *bus,
 	cfg_dbg("pnv_pci_read_config bus: %x devfn: %x +%x/%x -> %08x\n",
 		bus->number, devfn, where, size, *val);
 
-	/* Check if the PHB got frozen due to an error (no response) */
+	/*
+	 * Check if the specified PE has been put into frozen
+	 * state. On the other hand, we needn't do that while
+	 * the PHB has been put into frozen state because of
+	 * PHB-fatal errors.
+	 */
+#ifdef CONFIG_EEH
+	phb_pe = eeh_phb_pe_get(hose);
+	if (phb_pe && (phb_pe->state & EEH_PE_ISOLATED))
+		return PCIBIOS_SUCCESSFUL;
+
+	if (phb->eeh_enabled) {
+		if (*val == EEH_IO_ERROR_VALUE(size)) {
+			busdn = pci_bus_to_OF_node(bus);
+			for (dn = busdn->child; dn; dn = dn->sibling) {
+				struct pci_dn *pdn = PCI_DN(dn);
+
+				if (pdn && pdn->devfn == devfn &&
+				    eeh_dev_check_failure(of_node_to_eeh_dev(dn)))
+					return PCIBIOS_DEVICE_NOT_FOUND;
+			}
+		}
+	} else {
+		pnv_pci_config_check_eeh(phb, bus, bdfn);
+	}
+#else
 	pnv_pci_config_check_eeh(phb, bus, bdfn);
+#endif
 
 	return PCIBIOS_SUCCESSFUL;
 }
@@ -324,8 +356,14 @@ static int pnv_pci_write_config(struct pci_bus *bus,
 	default:
 		return PCIBIOS_FUNC_NOT_SUPPORTED;
 	}
+
 	/* Check if the PHB got frozen due to an error (no response) */
+#ifdef CONFIG_EEH
+	if (!phb->eeh_enabled)
+		pnv_pci_config_check_eeh(phb, bus, bdfn);
+#else
 	pnv_pci_config_check_eeh(phb, bus, bdfn);
+#endif
 
 	return PCIBIOS_SUCCESSFUL;
 }