1 files changed, 157 insertions, 35 deletions

diff --git a/drivers/base/component.c b/drivers/base/component.c
index c4778995cd72..f748430bb654 100644
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -18,6 +18,15 @@
 #include <linux/mutex.h>
 #include <linux/slab.h>
 
+struct component_match {
+        size_t alloc;
+        size_t num;
+        struct {
+                void *data;
+                int (*fn)(struct device *, void *);
+        } compare[0];
+};
+
 struct master {
         struct list_head node;
         struct list_head components;
@@ -25,6 +34,7 @@ struct master {
 
         const struct component_master_ops *ops;
         struct device *dev;
+        struct component_match *match;
 };
 
 struct component {
@@ -69,6 +79,11 @@ static void component_detach_master(struct master *master, struct component *c)
         c->master = NULL;
 }
 
+/*
+ * Add a component to a master, finding the component via the compare
+ * function and compare data.  This is safe to call for duplicate matches
+ * and will not result in the same component being added multiple times.
+ */
 int component_master_add_child(struct master *master,
         int (*compare)(struct device *, void *), void *compare_data)
 {
@@ -76,11 +91,12 @@ int component_master_add_child(struct master *master,
         int ret = -ENXIO;
 
         list_for_each_entry(c, &component_list, node) {
-                if (c->master)
+                if (c->master && c->master != master)
                         continue;
 
                 if (compare(c->dev, compare_data)) {
-                        component_attach_master(master, c);
+                        if (!c->master)
+                                component_attach_master(master, c);
                         ret = 0;
                         break;
                 }
@@ -90,6 +106,34 @@ int component_master_add_child(struct master *master,
 }
 EXPORT_SYMBOL_GPL(component_master_add_child);
 
+static int find_components(struct master *master)
+{
+        struct component_match *match = master->match;
+        size_t i;
+        int ret = 0;
+
+        if (!match) {
+                /*
+                 * Search the list of components, looking for components that
+                 * belong to this master, and attach them to the master.
+                 */
+                return master->ops->add_components(master->dev, master);
+        }
+
+        /*
+         * Scan the array of match functions and attach
+         * any components which are found to this master.
+         */
+        for (i = 0; i < match->num; i++) {
+                ret = component_master_add_child(master,
+                                                 match->compare[i].fn,
+                                                 match->compare[i].data);
+                if (ret)
+                        break;
+        }
+        return ret;
+}
+
 /* Detach all attached components from this master */
 static void master_remove_components(struct master *master)
 {
@@ -113,44 +157,44 @@ static void master_remove_components(struct master *master)
 static int try_to_bring_up_master(struct master *master,
         struct component *component)
 {
-        int ret = 0;
+        int ret;
 
-        if (!master->bound) {
-                /*
-                 * Search the list of components, looking for components that
-                 * belong to this master, and attach them to the master.
-                 */
-                if (master->ops->add_components(master->dev, master)) {
-                        /* Failed to find all components */
-                        master_remove_components(master);
-                        ret = 0;
-                        goto out;
-                }
+        if (master->bound)
+                return 0;
 
-                if (component && component->master != master) {
-                        master_remove_components(master);
-                        ret = 0;
-                        goto out;
-                }
+        /*
+         * Search the list of components, looking for components that
+         * belong to this master, and attach them to the master.
+         */
+        if (find_components(master)) {
+                /* Failed to find all components */
+                ret = 0;
+                goto out;
+        }
 
-                if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) {
-                        ret = -ENOMEM;
-                        goto out;
-                }
+        if (component && component->master != master) {
+                ret = 0;
+                goto out;
+        }
 
-                /* Found all components */
-                ret = master->ops->bind(master->dev);
-                if (ret < 0) {
-                        devres_release_group(master->dev, NULL);
-                        dev_info(master->dev, "master bind failed: %d\n", ret);
-                        master_remove_components(master);
-                        goto out;
-                }
+        if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) {
+                ret = -ENOMEM;
+                goto out;
+        }
 
-                master->bound = true;
-                ret = 1;
+        /* Found all components */
+        ret = master->ops->bind(master->dev);
+        if (ret < 0) {
+                devres_release_group(master->dev, NULL);
+                dev_info(master->dev, "master bind failed: %d\n", ret);
+                goto out;
         }
+
+        master->bound = true;
+        return 1;
+
 out:
+        master_remove_components(master);
 
         return ret;
 }
@@ -180,18 +224,89 @@ static void take_down_master(struct master *master)
         master_remove_components(master);
 }
 
-int component_master_add(struct device *dev,
-        const struct component_master_ops *ops)
+static size_t component_match_size(size_t num)
+{
+        return offsetof(struct component_match, compare[num]);
+}
+
+static struct component_match *component_match_realloc(struct device *dev,
+        struct component_match *match, size_t num)
+{
+        struct component_match *new;
+
+        if (match && match->alloc == num)
+                return match;
+
+        new = devm_kmalloc(dev, component_match_size(num), GFP_KERNEL);
+        if (!new)
+                return ERR_PTR(-ENOMEM);
+
+        if (match) {
+                memcpy(new, match, component_match_size(min(match->num, num)));
+                devm_kfree(dev, match);
+        } else {
+                new->num = 0;
+        }
+
+        new->alloc = num;
+
+        return new;
+}
+
+/*
+ * Add a component to be matched.
+ *
+ * The match array is first created or extended if necessary.
+ */
+void component_match_add(struct device *dev, struct component_match **matchptr,
+        int (*compare)(struct device *, void *), void *compare_data)
+{
+        struct component_match *match = *matchptr;
+
+        if (IS_ERR(match))
+                return;
+
+        if (!match || match->num == match->alloc) {
+                size_t new_size = match ? match->alloc + 16 : 15;
+
+                match = component_match_realloc(dev, match, new_size);
+
+                *matchptr = match;
+
+                if (IS_ERR(match))
+                        return;
+        }
+
+        match->compare[match->num].fn = compare;
+        match->compare[match->num].data = compare_data;
+        match->num++;
+}
+EXPORT_SYMBOL(component_match_add);
+
+int component_master_add_with_match(struct device *dev,
+        const struct component_master_ops *ops,
+        struct component_match *match)
 {
         struct master *master;
         int ret;
 
+        if (ops->add_components && match)
+                return -EINVAL;
+
+        if (match) {
+                /* Reallocate the match array for its true size */
+                match = component_match_realloc(dev, match, match->num);
+                if (IS_ERR(match))
+                        return PTR_ERR(match);
+        }
+
         master = kzalloc(sizeof(*master), GFP_KERNEL);
         if (!master)
                 return -ENOMEM;
 
         master->dev = dev;
         master->ops = ops;
+        master->match = match;
         INIT_LIST_HEAD(&master->components);
 
         /* Add to the list of available masters. */
@@ -209,6 +324,13 @@ int component_master_add(struct device *dev,
 
         return ret < 0 ? ret : 0;
 }
+EXPORT_SYMBOL_GPL(component_master_add_with_match);
+
+int component_master_add(struct device *dev,
+        const struct component_master_ops *ops)
+{
+        return component_master_add_with_match(dev, ops, NULL);
+}
 EXPORT_SYMBOL_GPL(component_master_add);
 
 void component_master_del(struct device *dev,