[PATCH v2 16/19] state: factor device path lookup into helper function

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

The #ifdef __BAREBOX__ is meant for easier synchronization with
dt-utils. We'll keep that intact, but move it out of the function to not
break reading flow. After sync, dt-utils would now need to implement

  of_cdev_find
  cdev_to_devpath

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
v1 -> v2:
  - no changes
---
 common/state/state.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/common/state/state.c b/common/state/state.c
index 11cc86ff73be..88e246198fb8 100644
--- a/common/state/state.c
+++ b/common/state/state.c
@@ -581,6 +581,20 @@ void state_release(struct state *state)
 	free(state);
 }
 
+#ifdef __BAREBOX__
+static char *cdev_to_devpath(struct cdev *cdev, off_t *offset, size_t *size)
+{
+	/*
+	 * We only accept partitions exactly mapping the barebox-state,
+	 * but dt-utils may need to set non-zero values here
+	 */
+	*offset = 0;
+	*size = 0;
+
+	return basprintf("/dev/%s", cdev->name);
+}
+#endif
+
 /*
  * state_new_from_node - create a new state instance from a device_node
  *
@@ -597,8 +611,9 @@ struct state *state_new_from_node(struct device_node *node, bool readonly)
 	const char *alias;
 	uint32_t stridesize;
 	struct device_node *partition_node;
-	off_t offset = 0;
-	size_t size = 0;
+	struct cdev *cdev;
+	off_t offset;
+	size_t size;
 
 	alias = of_alias_get(node);
 	if (!alias) {
@@ -617,11 +632,8 @@ struct state *state_new_from_node(struct device_node *node, bool readonly)
 		goto out_release_state;
 	}
 
-#ifdef __BAREBOX__
-	ret = of_find_path_by_node(partition_node, &state->backend_path, 0);
-#else
-	ret = of_get_devicepath(partition_node, &state->backend_path, &offset, &size);
-#endif
+	cdev = of_cdev_find(partition_node);
+	ret = PTR_ERR_OR_ZERO(cdev);
 	if (ret) {
 		if (ret != -EPROBE_DEFER)
 			dev_err(&state->dev, "state failed to parse path to backend: %s\n",
@@ -629,6 +641,10 @@ struct state *state_new_from_node(struct device_node *node, bool readonly)
 		goto out_release_state;
 	}
 
+	state->backend_path = cdev_to_devpath(cdev, &offset, &size);
+
+	pr_debug("%s: backend resolved to %s\n", node->full_name, state->backend_path);
+
 	state->backend_reproducible_name = of_get_reproducible_name(partition_node);
 
 	ret = of_property_read_string(node, "backend-type", &backend_type);
-- 
2.39.2