of: Add cpu node iterator for_each_of_cpu_node()

Iterating thru cpu nodes is a common pattern. Create a common iterator
which can find child nodes either by node name or device_type == cpu.
Using the former will allow for eventually dropping device_type
properties which are deprecated for FDT.

Cc: Frank Rowand <frowand.list@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>

diff --git a/drivers/of/base.c b/drivers/of/base.c
index a055cd1..4807db0 100644 (file)
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -742,6 +742,45 @@ struct device_node *of_get_next_available_child(const struct device_node *node,
 EXPORT_SYMBOL(of_get_next_available_child);
 
 /**
+ *     of_get_next_cpu_node - Iterate on cpu nodes
+ *     @prev:  previous child of the /cpus node, or NULL to get first
+ *
+ *     Returns a cpu node pointer with refcount incremented, use of_node_put()
+ *     on it when done. Returns NULL when prev is the last child. Decrements
+ *     the refcount of prev.
+ */
+struct device_node *of_get_next_cpu_node(struct device_node *prev)
+{
+       struct device_node *next = NULL;
+       unsigned long flags;
+       struct device_node *node;
+
+       if (!prev)
+               node = of_find_node_by_path("/cpus");
+
+       raw_spin_lock_irqsave(&devtree_lock, flags);
+       if (prev)
+               next = prev->sibling;
+       else if (node) {
+               next = node->child;
+               of_node_put(node);
+       }
+       for (; next; next = next->sibling) {
+               if (!(of_node_name_eq(next, "cpu") ||
+                     (next->type && !of_node_cmp(next->type, "cpu"))))
+                       continue;
+               if (!__of_device_is_available(next))
+                       continue;
+               if (of_node_get(next))
+                       break;
+       }
+       of_node_put(prev);
+       raw_spin_unlock_irqrestore(&devtree_lock, flags);
+       return next;
+}
+EXPORT_SYMBOL(of_get_next_cpu_node);
+
+/**
  * of_get_compatible_child - Find compatible child node
  * @parent:    parent node
  * @compatible:        compatible string

diff --git a/include/linux/of.h b/include/linux/of.h
index 99b0ebf..1aca0db 100644 (file)
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -353,6 +353,8 @@ extern const void *of_get_property(const struct device_node *node,
                                const char *name,
                                int *lenp);
 extern struct device_node *of_get_cpu_node(int cpu, unsigned int *thread);
+extern struct device_node *of_get_next_cpu_node(struct device_node *prev);
+
 #define for_each_property_of_node(dn, pp) \
        for (pp = dn->properties; pp != NULL; pp = pp->next)
 
@@ -754,6 +756,11 @@ static inline struct device_node *of_get_cpu_node(int cpu,
        return NULL;
 }
 
+static inline struct device_node *of_get_next_cpu_node(struct device_node *prev)
+{
+       return NULL;
+}
+
 static inline int of_n_addr_cells(struct device_node *np)
 {
        return 0;
@@ -1217,6 +1224,10 @@ static inline int of_property_read_s32(const struct device_node *np,
        for (child = of_get_next_available_child(parent, NULL); child != NULL; \
             child = of_get_next_available_child(parent, child))
 
+#define for_each_of_cpu_node(cpu) \
+       for (cpu = of_get_next_cpu_node(NULL); cpu != NULL; \
+            cpu = of_get_next_cpu_node(cpu))
+
 #define for_each_node_with_property(dn, prop_name) \
        for (dn = of_find_node_with_property(NULL, prop_name); dn; \
             dn = of_find_node_with_property(dn, prop_name))