of/flattree: Add of_flat_dt_match() helper function

This patch adds of_flat_dt_match() which tests a node for
compatibility with a list of values and converts the relevant powerpc
platform code to use it.  This approach simplifies the board support
code a bit.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>

1 files changed, 35 insertions, 2 deletions

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 8a90ee42071a..c787c3d95c60 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -78,19 +78,23 @@ void *of_fdt_get_property(struct boot_param_header *blob,
  * @blob: A device tree blob
  * @node: node to test
  * @compat: compatible string to compare with compatible list.
+ *
+ * On match, returns a non-zero value with smaller values returned for more
+ * specific compatible values.
  */
 int of_fdt_is_compatible(struct boot_param_header *blob,
                       unsigned long node, const char *compat)
 {
         const char *cp;
-        unsigned long cplen, l;
+        unsigned long cplen, l, score = 0;
 
         cp = of_fdt_get_property(blob, node, "compatible", &cplen);
         if (cp == NULL)
                 return 0;
         while (cplen > 0) {
+                score++;
                 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
-                        return 1;
+                        return score;
                 l = strlen(cp) + 1;
                 cp += l;
                 cplen -= l;
@@ -99,6 +103,27 @@ int of_fdt_is_compatible(struct boot_param_header *blob,
         return 0;
 }
 
+/**
+ * of_fdt_match - Return true if node matches a list of compatible values
+ */
+int of_fdt_match(struct boot_param_header *blob, unsigned long node,
+                 const char **compat)
+{
+        unsigned int tmp, score = 0;
+
+        if (!compat)
+                return 0;
+
+        while (*compat) {
+                tmp = of_fdt_is_compatible(blob, node, *compat);
+                if (tmp && (score == 0 || (tmp < score)))
+                        score = tmp;
+                compat++;
+        }
+
+        return score;
+}
+
 static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,
                                        unsigned long align)
 {
@@ -511,6 +536,14 @@ int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
         return of_fdt_is_compatible(initial_boot_params, node, compat);
 }
 
+/**
+ * of_flat_dt_match - Return true if node matches a list of compatible values
+ */
+int __init of_flat_dt_match(unsigned long node, const char **compat)
+{
+        return of_fdt_match(initial_boot_params, node, compat);
+}
+
 #ifdef CONFIG_BLK_DEV_INITRD
 /**
  * early_init_dt_check_for_initrd - Decode initrd location from flat tree