software node: implement reference properties

It is possible to store references to software nodes in the same fashion as
other static properties, so that users do not need to define separate
structures:

static const struct software_node gpio_bank_b_node = {
	.name = "B",
};

static const struct property_entry simone_key_enter_props[] = {
	PROPERTY_ENTRY_U32("linux,code", KEY_ENTER),
	PROPERTY_ENTRY_STRING("label", "enter"),
	PROPERTY_ENTRY_REF("gpios", &gpio_bank_b_node, 123, GPIO_ACTIVE_LOW),
	{ }
};

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 41 insertions, 8 deletions

diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
index 3d422918a53d..604d7327bba7 100644
--- a/drivers/base/swnode.c
+++ b/drivers/base/swnode.c
@@ -246,6 +246,13 @@ static int property_entry_copy_data(struct property_entry *dst,
 	if (!src->is_inline && !src->length)
 		return -ENODATA;
 
+	/*
+	 * Reference properties are never stored inline as
+	 * they are too big.
+	 */
+	if (src->type == DEV_PROP_REF && src->is_inline)
+		return -EINVAL;
+
 	if (src->length <= sizeof(dst->value)) {
 		dst_ptr = &dst->value;
 		dst->is_inline = true;
@@ -473,23 +480,49 @@ software_node_get_reference_args(const struct fwnode_handle *fwnode,
 {
 	struct swnode *swnode = to_swnode(fwnode);
 	const struct software_node_reference *ref;
+	const struct software_node_ref_args *ref_array;
+	const struct software_node_ref_args *ref_args;
 	const struct property_entry *prop;
 	struct fwnode_handle *refnode;
 	u32 nargs_prop_val;
 	int error;
 	int i;
 
-	if (!swnode || !swnode->node->references)
+	if (!swnode)
 		return -ENOENT;
 
-	for (ref = swnode->node->references; ref->name; ref++)
-		if (!strcmp(ref->name, propname))
-			break;
+	prop = property_entry_get(swnode->node->properties, propname);
+	if (prop) {
+		if (prop->type != DEV_PROP_REF)
+			return -EINVAL;
 
-	if (!ref->name || index > (ref->nrefs - 1))
-		return -ENOENT;
+		/*
+		 * We expect that references are never stored inline, even
+		 * single ones, as they are too big.
+		 */
+		if (prop->is_inline)
+			return -EINVAL;
+
+		if (index * sizeof(*ref_args) >= prop->length)
+			return -ENOENT;
+
+		ref_array = prop->pointer;
+		ref_args = &ref_array[index];
+	} else {
+		if (!swnode->node->references)
+			return -ENOENT;
+
+		for (ref = swnode->node->references; ref->name; ref++)
+			if (!strcmp(ref->name, propname))
+				break;
+
+		if (!ref->name || index > (ref->nrefs - 1))
+			return -ENOENT;
+
+		ref_args = &ref->refs[index];
+	}
 
-	refnode = software_node_fwnode(ref->refs[index].node);
+	refnode = software_node_fwnode(ref_args->node);
 	if (!refnode)
 		return -ENOENT;
 
@@ -510,7 +543,7 @@ software_node_get_reference_args(const struct fwnode_handle *fwnode,
 	args->nargs = nargs;
 
 	for (i = 0; i < nargs; i++)
-		args->args[i] = ref->refs[index].args[i];
+		args->args[i] = ref_args->args[i];
 
 	return 0;
 }