of: call __of_parse_phandle_with_args from of_parse_phandle

The simplest case of __of_parse_phandle_with_args() now implements the
semantics of of_parse_phandle(). Rewrite of_parse_phandle() to call
__of_parse_phandle_with_args() rather than open-coding the simple case.

Optimize __of_parse_phandle_with_args() so that it doesn't call
of_find_node_by_phandle() except when it's strictly needed. This avoids
introducing too much overhead when replacing of_parse_phandle().

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>

1 files changed, 20 insertions, 11 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 1f80acf4c16a..7c75d7551eb9 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1111,13 +1111,20 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
                 if (phandle) {
                         /*
                          * Find the provider node and parse the #*-cells
-                         * property to determine the argument length
+                         * property to determine the argument length.
+                         *
+                         * This is not needed if the cell count is hard-coded
+                         * (i.e. cells_name not set, but cell_count is set),
+                         * except when we're going to return the found node
+                         * below.
                          */
-                        node = of_find_node_by_phandle(phandle);
-                        if (!node) {
-                                pr_err("%s: could not find phandle\n",
-                                         np->full_name);
-                                goto err;
+                        if (cells_name || cur_index == index) {
+                                node = of_find_node_by_phandle(phandle);
+                                if (!node) {
+                                        pr_err("%s: could not find phandle\n",
+                                                np->full_name);
+                                        goto err;
+                                }
                         }
 
                         if (cells_name) {
@@ -1202,14 +1209,16 @@ static int __of_parse_phandle_with_args(const struct device_node *np,
 struct device_node *of_parse_phandle(const struct device_node *np,
                                      const char *phandle_name, int index)
 {
-        const __be32 *phandle;
-        int size;
+        struct of_phandle_args args;
+
+        if (index < 0)
+                return NULL;
 
-        phandle = of_get_property(np, phandle_name, &size);
-        if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
+        if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
+                                         index, &args))
                 return NULL;
 
-        return of_find_node_by_phandle(be32_to_cpup(phandle + index));
+        return args.np;
 }
 EXPORT_SYMBOL(of_parse_phandle);