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>

4 files changed, 84 insertions, 11 deletions

diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index b76f58c124ca..fab7743c2640 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/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);
diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index c25064b7d667..86e25702aaca 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/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);
diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
index 995c2a284630..fbd01eba4473 100644
--- a/arch/powerpc/kernel/eeh_pe.c
+++ b/arch/powerpc/kernel/eeh_pe.c
@@ -792,6 +792,66 @@ void eeh_pe_restore_bars(struct eeh_pe *pe)
 }
 
 /**
+ * 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
  *
diff --git a/arch/powerpc/platforms/powernv/eeh-ioda.c b/arch/powerpc/platforms/powernv/eeh-ioda.c
index 9c002099f875..8ad0c5b891f4 100644
--- a/arch/powerpc/platforms/powernv/eeh-ioda.c
+++ b/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;
                         }