Some applications require applying the same overlay to a different
target according to some external condition (for instance depending
on the slot a card has been inserted, the overlay target is different).
The indirect target use requires using the new
of_overlay_create_indirect() API which uses a text selector.
The format requires the use of a target-indirect node as follows:
fragment@0 {
target-indirect {
foo { target = <&foo_target>; };
bar { target = <&bar_target>; };
};
};
Calling of_overlay_create_indirect() with a "foo" argument selects
the foo_target and so on.
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
---
drivers/of/overlay.c | 126 +++++++++++++++++++++++++++++++++++++++++----------
include/linux/of.h | 8 ++++
2 files changed, 110 insertions(+), 24 deletions(-)
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index fdfc487..364b619 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -75,6 +75,7 @@ struct of_overlay {
const struct attribute_group **attr_groups;
struct of_changeset cset;
struct kobject kobj;
+ char *indirect_id;
};
/* master enable switch; once set to 0 can't be re-enabled */
@@ -220,14 +221,8 @@ static int of_overlay_apply(struct of_overlay *ov)
return 0;
}
-/*
- * Find the target node using a number of different strategies
- * in order of preference
- *
- * "target" property containing the phandle of the target
- * "target-path" property containing the path of the target
- */
-static struct device_node *find_target_node(struct device_node *info_node)
+static struct device_node *find_target_node_direct(struct of_overlay *ov,
+ struct device_node *info_node)
{
const char *path;
u32 val;
@@ -238,17 +233,66 @@ static struct device_node *find_target_node(struct device_node *info_node)
if (ret == 0)
return of_find_node_by_phandle(val);
- /* now try to locate by path */
+ /* failed, try to locate by path */
ret = of_property_read_string(info_node, "target-path", &path);
if (ret == 0)
return of_find_node_by_path(path);
- pr_err("%s: Failed to find target for node %p (%s)\n", __func__,
- info_node, info_node->name);
-
return NULL;
}
+/*
+ * Find the target node using a number of different strategies
+ * in order of preference. Respects the indirect id if available.
+ *
+ * "target" property containing the phandle of the target
+ * "target-path" property containing the path of the target
+ */
+static struct device_node *find_target_node(struct of_overlay *ov,
+ struct device_node *info_node)
+{
+ struct device_node *target;
+ struct device_node *target_indirect;
+ struct device_node *indirect;
+
+ /* try direct target */
+ target = find_target_node_direct(ov, info_node);
+ if (target)
+ return target;
+
+ /* try indirect if there */
+ if (!ov->indirect_id)
+ return NULL;
+
+ target_indirect = of_get_child_by_name(info_node, "target-indirect");
+ if (!target_indirect) {
+ pr_err("%s: Failed to find target-indirect node at %s\n",
+ __func__,
+ of_node_full_name(info_node));
+ return NULL;
+ }
+
+ indirect = of_get_child_by_name(target_indirect, ov->indirect_id);
+ of_node_put(target_indirect);
+ if (!indirect) {
+ pr_err("%s: Failed to find indirect child node \"%s\" at %s\n",
+ __func__, ov->indirect_id,
+ of_node_full_name(info_node));
+ return NULL;
+ }
+
+ target = find_target_node_direct(ov, indirect);
+
+ if (!target) {
+ pr_err("%s: Failed to find target for \"%s\" at %s\n",
+ __func__, ov->indirect_id,
+ of_node_full_name(indirect));
+ }
+ of_node_put(indirect);
+
+ return target;
+}
+
/**
* of_fill_overlay_info() - Fill an overlay info structure
* @ov Overlay to fill
@@ -270,7 +314,7 @@ static int of_fill_overlay_info(struct of_overlay *ov,
if (ovinfo->overlay == NULL)
goto err_fail;
- ovinfo->target = find_target_node(info_node);
+ ovinfo->target = find_target_node(ov, info_node);
if (ovinfo->target == NULL)
goto err_fail;
@@ -418,6 +462,7 @@ void of_overlay_release(struct kobject *kobj)
{
struct of_overlay *ov = kobj_to_overlay(kobj);
+ kfree(ov->indirect_id);
kfree(ov);
}
@@ -473,17 +518,8 @@ static struct kobj_type of_overlay_ktype = {
static struct kset *ov_kset;
-/**
- * of_overlay_create() - Create and apply an overlay
- * @tree: Device node containing all the overlays
- *
- * Creates and applies an overlay while also keeping track
- * of the overlay in a list. This list can be used to prevent
- * illegal overlay removals.
- *
- * Returns the id of the created overlay, or a negative error number
- */
-int of_overlay_create(struct device_node *tree)
+static int __of_overlay_create(struct device_node *tree,
+ const char *indirect_id)
{
struct of_overlay *ov;
int err, id;
@@ -498,6 +534,14 @@ int of_overlay_create(struct device_node *tree)
return -ENOMEM;
ov->id = -1;
+ if (indirect_id) {
+ ov->indirect_id = kstrdup(indirect_id, GFP_KERNEL);
+ if (!ov->indirect_id) {
+ err = -ENOMEM;
+ goto err_no_mem;
+ }
+ }
+
INIT_LIST_HEAD(&ov->node);
of_changeset_init(&ov->cset);
@@ -572,13 +616,47 @@ err_free_idr:
idr_remove(&ov_idr, ov->id);
err_destroy_trans:
of_changeset_destroy(&ov->cset);
+err_no_mem:
+ kfree(ov->indirect_id);
kfree(ov);
mutex_unlock(&of_mutex);
return err;
}
+
+/**
+ * of_overlay_create() - Create and apply an overlay
+ * @tree: Device node containing all the overlays
+ *
+ * Creates and applies an overlay while also keeping track
+ * of the overlay in a list. This list can be used to prevent
+ * illegal overlay removals.
+ *
+ * Returns the id of the created overlay, or a negative error number
+ */
+int of_overlay_create(struct device_node *tree)
+{
+ return __of_overlay_create(tree, NULL);
+}
EXPORT_SYMBOL_GPL(of_overlay_create);
+/**
+ * of_overlay_create_indirect() - Create and apply an overlay
+ * @tree: Device node containing all the overlays
+ * @id: Indirect property phandle
+ *
+ * Creates and applies an overlay while also keeping track
+ * of the overlay in a list. This list can be used to prevent
+ * illegal overlay removals.
+ *
+ * Returns the id of the created overlay, or a negative error number
+ */
+int of_overlay_create_indirect(struct device_node *tree, const char *id)
+{
+ return __of_overlay_create(tree, id);
+}
+EXPORT_SYMBOL_GPL(of_overlay_create_indirect);
+
/* check whether the given node, lies under the given tree */
static int overlay_subtree_check(struct device_node *tree,
struct device_node *dn)
diff --git a/include/linux/of.h b/include/linux/of.h
index f015911..4c220fb 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1226,6 +1226,8 @@ int of_overlay_create(struct device_node *tree);
int of_overlay_destroy(int id);
int of_overlay_destroy_all(void);
+int of_overlay_create_indirect(struct device_node *tree, const char *id);
+
#else
static inline int of_overlay_create(struct device_node *tree)
@@ -1243,6 +1245,12 @@ static inline int of_overlay_destroy_all(void)
return -ENOTSUPP;
}
+static inline int of_overlay_create_indirect(struct device_node *tree,
+ const char *id)
+{
+ return -ENOTSUPP;
+}
+
#endif
#endif /* _LINUX_OF_H */
--
1.7.12
--
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