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>

1 files changed, 60 insertions, 0 deletions

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
  *