[PATCH v2 6/7] mtd: ubi: populate ubi volume fwnode

From: Daniel Golle
Date: Sat Aug 05 2023 - 12:26:45 EST


Look for the 'volumes' subnode of an MTD partition attached to a UBI
device and attach matching child nodes to UBI volumes.
This allows UBI volumes to be referenced in device tree, e.g. for use
as NVMEM providers.

Signed-off-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
---
drivers/mtd/ubi/vmt.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)

diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index eed4b57c61bda..3b997256cfba7 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -124,6 +124,35 @@ static void vol_release(struct device *dev)
kfree(vol);
}

+static struct fwnode_handle *find_volume_fwnode(struct ubi_volume *vol)
+{
+ struct fwnode_handle *fw_vols, *fw_vol;
+ const char *volname;
+ u32 reg;
+
+ fw_vols = device_get_named_child_node(vol->dev.parent->parent, "volumes");
+ if (!fw_vols)
+ return NULL;
+
+ fwnode_for_each_child_node(fw_vols, fw_vol) {
+ if (!fwnode_property_read_string(fw_vol, "volname", &volname) &&
+ strncmp(volname, vol->name, vol->name_len))
+ continue;
+
+ /*
+ * volume id (reg) in device tree greater than UBI_MAX_VOLUMES
+ * can be used to match by volname only
+ */
+ if (!fwnode_property_read_u32(fw_vol, "reg", &reg) &&
+ reg < UBI_MAX_VOLUMES && vol->vol_id != reg)
+ continue;
+
+ return fw_vol;
+ }
+
+ return NULL;
+}
+
/**
* ubi_create_volume - create volume.
* @ubi: UBI device description object
@@ -223,6 +252,7 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
vol->name_len = req->name_len;
memcpy(vol->name, req->name, vol->name_len);
vol->ubi = ubi;
+ device_set_node(&vol->dev, find_volume_fwnode(vol));

/*
* Finish all pending erases because there may be some LEBs belonging
@@ -597,6 +627,7 @@ int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol)
vol->dev.class = &ubi_class;
vol->dev.groups = volume_dev_groups;
dev_set_name(&vol->dev, "%s_%d", ubi->ubi_name, vol->vol_id);
+ device_set_node(&vol->dev, find_volume_fwnode(vol));
err = device_register(&vol->dev);
if (err) {
cdev_del(&vol->cdev);
--
2.41.0