1 files changed, 74 insertions, 76 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 10b51106c854..89e888a78899 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -342,27 +342,72 @@ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
 }
 EXPORT_SYMBOL(of_get_cpu_node);
 
-/** Checks if the given "compat" string matches one of the strings in
- * the device's "compatible" property
+/**
+ * __of_device_is_compatible() - Check if the node matches given constraints
+ * @device: pointer to node
+ * @compat: required compatible string, NULL or "" for any match
+ * @type: required device_type value, NULL or "" for any match
+ * @name: required node name, NULL or "" for any match
+ *
+ * Checks if the given @compat, @type and @name strings match the
+ * properties of the given @device. A constraints can be skipped by
+ * passing NULL or an empty string as the constraint.
+ *
+ * Returns 0 for no match, and a positive integer on match. The return
+ * value is a relative score with larger values indicating better
+ * matches. The score is weighted for the most specific compatible value
+ * to get the highest score. Matching type is next, followed by matching
+ * name. Practically speaking, this results in the following priority
+ * order for matches:
+ *
+ * 1. specific compatible && type && name
+ * 2. specific compatible && type
+ * 3. specific compatible && name
+ * 4. specific compatible
+ * 5. general compatible && type && name
+ * 6. general compatible && type
+ * 7. general compatible && name
+ * 8. general compatible
+ * 9. type && name
+ * 10. type
+ * 11. name
  */
 static int __of_device_is_compatible(const struct device_node *device,
-                                     const char *compat)
+                                     const char *compat, const char *type, const char *name)
 {
-        const char* cp;
-        int cplen, l;
+        struct property *prop;
+        const char *cp;
+        int index = 0, score = 0;
+
+        /* Compatible match has highest priority */
+        if (compat && compat[0]) {
+                prop = __of_find_property(device, "compatible", NULL);
+                for (cp = of_prop_next_string(prop, NULL); cp;
+                     cp = of_prop_next_string(prop, cp), index++) {
+                        if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
+                                score = INT_MAX/2 - (index << 2);
+                                break;
+                        }
+                }
+                if (!score)
+                        return 0;
+        }
 
-        cp = __of_get_property(device, "compatible", &cplen);
-        if (cp == NULL)
-                return 0;
-        while (cplen > 0) {
-                if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
-                        return 1;
-                l = strlen(cp) + 1;
-                cp += l;
-                cplen -= l;
+        /* Matching type is better than matching name */
+        if (type && type[0]) {
+                if (!device->type || of_node_cmp(type, device->type))
+                        return 0;
+                score += 2;
         }
 
-        return 0;
+        /* Matching name is a bit better than not */
+        if (name && name[0]) {
+                if (!device->name || of_node_cmp(name, device->name))
+                        return 0;
+                score++;
+        }
+
+        return score;
 }
 
 /** Checks if the given "compat" string matches one of the strings in
@@ -375,7 +420,7 @@ int of_device_is_compatible(const struct device_node *device,
         int res;
 
         raw_spin_lock_irqsave(&devtree_lock, flags);
-        res = __of_device_is_compatible(device, compat);
+        res = __of_device_is_compatible(device, compat, NULL, NULL);
         raw_spin_unlock_irqrestore(&devtree_lock, flags);
         return res;
 }
@@ -681,10 +726,7 @@ struct device_node *of_find_compatible_node(struct device_node *from,
         raw_spin_lock_irqsave(&devtree_lock, flags);
         np = from ? from->allnext : of_allnodes;
         for (; np; np = np->allnext) {
-                if (type
-                    && !(np->type && (of_node_cmp(np->type, type) == 0)))
-                        continue;
-                if (__of_device_is_compatible(np, compatible) &&
+                if (__of_device_is_compatible(np, compatible, type, NULL) &&
                     of_node_get(np))
                         break;
         }
@@ -730,65 +772,26 @@ out:
 }
 EXPORT_SYMBOL(of_find_node_with_property);
 
-static const struct of_device_id *
-of_match_compatible(const struct of_device_id *matches,
-                        const struct device_node *node)
-{
-        const char *cp;
-        int cplen, l;
-        const struct of_device_id *m;
-
-        cp = __of_get_property(node, "compatible", &cplen);
-        while (cp && (cplen > 0)) {
-                m = matches;
-                while (m->name[0] || m->type[0] || m->compatible[0]) {
-                        /* Only match for the entries without type and name */
-                        if (m->name[0] || m->type[0] ||
-                                of_compat_cmp(m->compatible, cp,
-                                         strlen(m->compatible)))
-                                m++;
-                        else
-                                return m;
-                }
-
-                /* Get node's next compatible string */
-                l = strlen(cp) + 1;
-                cp += l;
-                cplen -= l;
-        }
-
-        return NULL;
-}
-
 static
 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
                                            const struct device_node *node)
 {
-        const struct of_device_id *m;
+        const struct of_device_id *best_match = NULL;
+        int score, best_score = 0;
 
         if (!matches)
                 return NULL;
 
-        m = of_match_compatible(matches, node);
-        if (m)
-                return m;
-
-        while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
-                int match = 1;
-                if (matches->name[0])
-                        match &= node->name
-                                && !strcmp(matches->name, node->name);
-                if (matches->type[0])
-                        match &= node->type
-                                && !strcmp(matches->type, node->type);
-                if (matches->compatible[0])
-                        match &= __of_device_is_compatible(node,
-                                                           matches->compatible);
-                if (match)
-                        return matches;
-                matches++;
+        for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
+                score = __of_device_is_compatible(node, matches->compatible,
+                                                  matches->type, matches->name);
+                if (score > best_score) {
+                        best_match = matches;
+                        best_score = score;
+                }
         }
-        return NULL;
+
+        return best_match;
 }
 
 /**
@@ -796,12 +799,7 @@ const struct of_device_id *__of_match_node(const struct of_device_id *matches,
  *      @matches:       array of of device match structures to search in
  *      @node:          the of device structure to match against
  *
- *      Low level utility function used by device matching. We have two ways
- *      of matching:
- *      - Try to find the best compatible match by comparing each compatible
- *        string of device node with all the given matches respectively.
- *      - If the above method failed, then try to match the compatible by using
- *        __of_device_is_compatible() besides the match in type and name.
+ *      Low level utility function used by device matching.
  */
 const struct of_device_id *of_match_node(const struct of_device_id *matches,
                                          const struct device_node *node)