PCI: rpaphp: Document is_php_dn()

[~andy/linux] / drivers / pci / hotplug / rpaphp_core.c

diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c
index e9c157d30e824bd739eb9d61eac5fdbd742e9f6c..aa8d9a60d0a6355ce81fd864be53cd99dbdf3670 100644 (file)
--- a/drivers/pci/hotplug/rpaphp_core.c
+++ b/drivers/pci/hotplug/rpaphp_core.c
@@ -262,6 +262,14 @@ static int is_php_type(char *drc_type)
        return 1;
 }
 
+/**
+ * is_php_dn() - return 1 if this is a hotpluggable pci slot, else 0
+ *
+ * This routine will return true only if the device node is
+ * a hotpluggable slot. This routine will return false
+ * for built-in pci slots (even when the built-in slots are
+ * dlparable.)
+ */
 static int is_php_dn(struct device_node *dn, const int **indexes,
                const int **names, const int **types, const int **power_domains)
 {
@@ -269,24 +277,31 @@ static int is_php_dn(struct device_node *dn, const int **indexes,
        int rc;
 
        rc = get_children_props(dn, indexes, names, &drc_types, power_domains);
-       if (rc >= 0) {
-               if (is_php_type((char *) &drc_types[1])) {
-                       *types = drc_types;
-                       return 1;
-               }
-       }
+       if (rc < 0)
+               return 0;
 
-       return 0;
+       if (!is_php_type((char *) &drc_types[1]))
+               return 0;
+
+       *types = drc_types;
+       return 1;
 }
 
 /**
- * rpaphp_add_slot -- add hotplug or dlpar slot
+ * rpaphp_add_slot -- declare a hotplug slot to the hotplug subsystem.
+ * @dn device node of slot
  *
- *     rpaphp not only registers PCI hotplug slots(HOTPLUG), 
- *     but also logical DR slots(EMBEDDED).
- *     HOTPLUG slot: An adapter can be physically added/removed. 
- *     EMBEDDED slot: An adapter can be logically removed/added
- *               from/to a partition with the slot.
+ * This subroutine will register a hotplugable slot with the
+ * PCI hotplug infrastructure. This routine is typicaly called
+ * during boot time, if the hotplug slots are present at boot time,
+ * or is called later, by the dlpar add code, if the slot is
+ * being dynamically added during runtime.
+ *
+ * If the device node points at an embedded (built-in) slot, this
+ * routine will just return without doing anything, since embedded
+ * slots cannot be hotplugged.
+ *
+ * To remove a slot, it suffices to call rpaphp_deregister_slot()
  */
 int rpaphp_add_slot(struct device_node *dn)
 {
@@ -299,6 +314,7 @@ int rpaphp_add_slot(struct device_node *dn)
        if (!dn->name || strcmp(dn->name, "pci"))
                return 0;
 
+       /* If this is not a hotplug slot, return without doing anything. */
        if (!is_php_dn(dn, &indexes, &names, &types, &power_domains))
                return 0;
 
@@ -318,7 +334,10 @@ int rpaphp_add_slot(struct device_node *dn)
                dbg("Found drc-index:0x%x drc-name:%s drc-type:%s\n",
                                indexes[i + 1], name, type);
 
-               retval = rpaphp_register_pci_slot(slot);
+               retval = rpaphp_enable_slot(slot);
+               if (!retval)
+                       retval = rpaphp_register_slot(slot);
+
                if (retval)
                        dealloc_slot_struct(slot);