--- /dev/null
+From ad9b10d1eaada169bd764abcab58f08538877e26 Mon Sep 17 00:00:00 2001
+From: Christian Marangi <ansuelsmth@gmail.com>
+Date: Wed, 22 Jun 2022 03:06:28 +0200
+Subject: mtd: core: introduce of support for dynamic partitions
+
+We have many parser that register mtd partitions at runtime. One example
+is the cmdlinepart or the smem-part parser where the compatible is defined
+in the dts and the partitions gets detected and registered by the
+parser. This is problematic for the NVMEM subsystem that requires an OF
+node to detect NVMEM cells.
+
+To fix this problem, introduce an additional logic that will try to
+assign an OF node to the MTD if declared.
+
+On MTD addition, it will be checked if the MTD has an OF node and if
+not declared will check if a partition with the same label / node name is
+declared in DTS. If an exact match is found, the partition dynamically
+allocated by the parser will have a connected OF node.
+
+The NVMEM subsystem will detect the OF node and register any NVMEM cells
+declared statically in the DTS.
+
+Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
+Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
+Link: https://lore.kernel.org/linux-mtd/20220622010628.30414-4-ansuelsmth@gmail.com
+---
+ drivers/mtd/mtdcore.c | 61 +++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 61 insertions(+)
+
+--- a/drivers/mtd/mtdcore.c
++++ b/drivers/mtd/mtdcore.c
+@@ -589,6 +589,66 @@ static int mtd_nvmem_add(struct mtd_info
+ return 0;
+ }
+
++static void mtd_check_of_node(struct mtd_info *mtd)
++{
++ struct device_node *partitions, *parent_dn, *mtd_dn = NULL;
++ const char *pname, *prefix = "partition-";
++ int plen, mtd_name_len, offset, prefix_len;
++ struct mtd_info *parent;
++ bool found = false;
++
++ /* Check if MTD already has a device node */
++ if (dev_of_node(&mtd->dev))
++ return;
++
++ /* Check if a partitions node exist */
++ parent = mtd_get_master(mtd);
++ parent_dn = dev_of_node(&parent->dev);
++ if (!parent_dn)
++ return;
++
++ partitions = of_get_child_by_name(parent_dn, "partitions");
++ if (!partitions)
++ goto exit_parent;
++
++ prefix_len = strlen(prefix);
++ mtd_name_len = strlen(mtd->name);
++
++ /* Search if a partition is defined with the same name */
++ for_each_child_of_node(partitions, mtd_dn) {
++ offset = 0;
++
++ /* Skip partition with no/wrong prefix */
++ if (!of_node_name_prefix(mtd_dn, "partition-"))
++ continue;
++
++ /* Label have priority. Check that first */
++ if (of_property_read_string(mtd_dn, "label", &pname)) {
++ of_property_read_string(mtd_dn, "name", &pname);
++ offset = prefix_len;
++ }
++
++ plen = strlen(pname) - offset;
++ if (plen == mtd_name_len &&
++ !strncmp(mtd->name, pname + offset, plen)) {
++ found = true;
++ break;
++ }
++ }
++
++ if (!found)
++ goto exit_partitions;
++
++ /* Set of_node only for nvmem */
++ if (of_device_is_compatible(mtd_dn, "nvmem-cells"))
++ mtd_set_of_node(mtd, mtd_dn);
++
++exit_partitions:
++ of_node_put(partitions);
++exit_parent:
++ of_node_put(parent_dn);
++}
++
+ /**
+ * add_mtd_device - register an MTD device
+ * @mtd: pointer to new MTD device info structure
+@@ -672,6 +732,7 @@ int add_mtd_device(struct mtd_info *mtd)
+ mtd->dev.devt = MTD_DEVT(i);
+ dev_set_name(&mtd->dev, "mtd%d", i);
+ dev_set_drvdata(&mtd->dev, mtd);
++ mtd_check_of_node(mtd);
+ of_node_get(mtd_get_of_node(mtd));
+ error = device_register(&mtd->dev);
+ if (error)
projects / openwrt / staging / hauke.git / commitdiff