powerpc/eeh: Dump PE location code

As Ben suggested, it's meaningful to dump PE's location code
for site engineers when hitting EEH errors. The patch introduces
function eeh_pe_loc_get() to retireve the location code from
dev-tree so that we can output it when hitting EEH errors.

If primary PE bus is root bus, the PHB's dev-node would be tried
prior to root port's dev-node. Otherwise, the upstream bridge's
dev-node of the primary PE bus will be check for the location code
directly.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/eeh.h

@@ -254,6 +254,7 @@ void *eeh_pe_traverse(struct eeh_pe *root,
 void *eeh_pe_dev_traverse(struct eeh_pe *root,
 		eeh_traverse_func fn, void *flag);
 void eeh_pe_restore_bars(struct eeh_pe *pe);
+const char *eeh_pe_loc_get(struct eeh_pe *pe);
 struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe);
 
 void *eeh_dev_init(struct device_node *dn, void *data);

arch/powerpc/kernel/eeh.c

@@ -330,8 +330,8 @@ static int eeh_phb_check_failure(struct eeh_pe *pe)
 	eeh_pe_state_mark(phb_pe, EEH_PE_ISOLATED);
 	eeh_serialize_unlock(flags);
 
-	pr_err("EEH: PHB#%x failure detected\n",
-		phb_pe->phb->global_number);
+	pr_err("EEH: PHB#%x failure detected, location: %s\n",
+		phb_pe->phb->global_number, eeh_pe_loc_get(phb_pe));
 	dump_stack();
 	eeh_send_failure_event(phb_pe);
 
@@ -362,7 +362,7 @@ int eeh_dev_check_failure(struct eeh_dev *edev)
 	unsigned long flags;
 	struct device_node *dn;
 	struct pci_dev *dev;
-	struct eeh_pe *pe, *parent_pe;
+	struct eeh_pe *pe, *parent_pe, *phb_pe;
 	int rc = 0;
 	const char *location;
 
@@ -481,8 +481,11 @@ int eeh_dev_check_failure(struct eeh_dev *edev)
 	 * a stack trace will help the device-driver authors figure
 	 * out what happened.  So print that out.
 	 */
-	pr_err("EEH: Frozen PE#%x detected on PHB#%x\n",
-		pe->addr, pe->phb->global_number);
+	phb_pe = eeh_phb_pe_get(pe->phb);
+	pr_err("EEH: Frozen PHB#%x-PE#%x detected\n",
+	       pe->phb->global_number, pe->addr);
+	pr_err("EEH: PE location: %s, PHB location: %s\n",
+	       eeh_pe_loc_get(pe), eeh_pe_loc_get(phb_pe));
 	dump_stack();
 
 	eeh_send_failure_event(pe);

arch/powerpc/kernel/eeh_pe.c

@@ -791,6 +791,66 @@ void eeh_pe_restore_bars(struct eeh_pe *pe)
 	eeh_pe_dev_traverse(pe, eeh_restore_one_device_bars, NULL);
 }
 
+/**
+ * eeh_pe_loc_get - Retrieve location code binding to the given PE
+ * @pe: EEH PE
+ *
+ * Retrieve the location code of the given PE. If the primary PE bus
+ * is root bus, we will grab location code from PHB device tree node
+ * or root port. Otherwise, the upstream bridge's device tree node
+ * of the primary PE bus will be checked for the location code.
+ */
+const char *eeh_pe_loc_get(struct eeh_pe *pe)
+{
+	struct pci_controller *hose;
+	struct pci_bus *bus = eeh_pe_bus_get(pe);
+	struct pci_dev *pdev;
+	struct device_node *dn;
+	const char *loc;
+
+	if (!bus)
+		return "N/A";
+
+	/* PHB PE or root PE ? */
+	if (pci_is_root_bus(bus)) {
+		hose = pci_bus_to_host(bus);
+		loc = of_get_property(hose->dn,
+				"ibm,loc-code", NULL);
+		if (loc)
+			return loc;
+		loc = of_get_property(hose->dn,
+				"ibm,io-base-loc-code", NULL);
+		if (loc)
+			return loc;
+
+		pdev = pci_get_slot(bus, 0x0);
+	} else {
+		pdev = bus->self;
+	}
+
+	if (!pdev) {
+		loc = "N/A";
+		goto out;
+	}
+
+	dn = pci_device_to_OF_node(pdev);
+	if (!dn) {
+		loc = "N/A";
+		goto out;
+	}
+
+	loc = of_get_property(dn, "ibm,loc-code", NULL);
+	if (!loc)
+		loc = of_get_property(dn, "ibm,slot-location-code", NULL);
+	if (!loc)
+		loc = "N/A";
+
+out:
+	if (pci_is_root_bus(bus) && pdev)
+		pci_dev_put(pdev);
+	return loc;
+}
+
 /**
  * eeh_pe_bus_get - Retrieve PCI bus according to the given PE
  * @pe: EEH PE

arch/powerpc/platforms/powernv/eeh-ioda.c

@@ -774,19 +774,24 @@ static int ioda_eeh_next_error(struct eeh_pe **pe)
 		case OPAL_EEH_PHB_ERROR:
 			if (be16_to_cpu(severity) == OPAL_EEH_SEV_PHB_DEAD) {
 				*pe = phb_pe;
-				pr_err("EEH: dead PHB#%x detected\n",
-					hose->global_number);
+				pr_err("EEH: dead PHB#%x detected, "
+				       "location: %s\n",
+				       hose->global_number,
+				       eeh_pe_loc_get(phb_pe));
 				ret = EEH_NEXT_ERR_DEAD_PHB;
 			} else if (be16_to_cpu(severity) ==
 						OPAL_EEH_SEV_PHB_FENCED) {
 				*pe = phb_pe;
-				pr_err("EEH: fenced PHB#%x detected\n",
-					hose->global_number);
+				pr_err("EEH: Fenced PHB#%x detected, "
+				       "location: %s\n",
+				       hose->global_number,
+				       eeh_pe_loc_get(phb_pe));
 				ret = EEH_NEXT_ERR_FENCED_PHB;
 			} else if (be16_to_cpu(severity) == OPAL_EEH_SEV_INF) {
 				pr_info("EEH: PHB#%x informative error "
-					"detected\n",
-					hose->global_number);
+					"detected, location: %s\n",
+					hose->global_number,
+					eeh_pe_loc_get(phb_pe));
 				ioda_eeh_phb_diag(hose);
 				ret = EEH_NEXT_ERR_NONE;
 			}
@@ -802,6 +807,8 @@ static int ioda_eeh_next_error(struct eeh_pe **pe)
 				/* Try best to clear it */
 				pr_info("EEH: Clear non-existing PHB#%x-PE#%llx\n",
 					hose->global_number, frozen_pe_no);
+				pr_info("EEH: PHB location: %s\n",
+					eeh_pe_loc_get(phb_pe));
 				opal_pci_eeh_freeze_clear(phb->opal_id, frozen_pe_no,
 					OPAL_EEH_ACTION_CLEAR_FREEZE_ALL);
 				ret = EEH_NEXT_ERR_NONE;
@@ -810,6 +817,8 @@ static int ioda_eeh_next_error(struct eeh_pe **pe)
 			} else {
 				pr_err("EEH: Frozen PE#%x on PHB#%x detected\n",
 					(*pe)->addr, (*pe)->phb->global_number);
+				pr_err("EEH: PE location: %s, PHB location: %s\n",
+					eeh_pe_loc_get(*pe), eeh_pe_loc_get(phb_pe));
 				ret = EEH_NEXT_ERR_FROZEN_PE;
 			}