kernel: mtd: backport extended dynamic partitions support

This gets rid of "nvmem-cells" limitation. Dynamic partitions can be
defined for any (sub)partitions layout.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit 4eda414b09)

target/linux/generic/backport-5.4/417-v6.2-0001-mtd-core-simplify-a-bit-code-find-partition-matching.patch

@@ -0,0 +1,65 @@
+From 63db0cb35e1cb3b3c134906d1062f65513fdda2d Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Tue, 4 Oct 2022 10:37:09 +0200
+Subject: [PATCH] mtd: core: simplify (a bit) code find partition-matching
+ dynamic OF node
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+1. Don't hardcode "partition-" string twice
+2. Use simpler logic & use ->name to avoid of_property_read_string()
+3. Use mtd_get_of_node() helper
+
+Cc: Christian Marangi <ansuelsmth@gmail.com>
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
+Link: https://lore.kernel.org/linux-mtd/20221004083710.27704-1-zajec5@gmail.com
+---
+ drivers/mtd/mtdcore.c | 16 +++++++---------
+ 1 file changed, 7 insertions(+), 9 deletions(-)
+
+--- a/drivers/mtd/mtdcore.c
++++ b/drivers/mtd/mtdcore.c
+@@ -594,18 +594,16 @@ static void mtd_check_of_node(struct 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))
++	if (mtd_get_of_node(mtd))
+ 		return;
+ 
+ 	/* Check if a partitions node exist */
+ 	if (!mtd_is_partition(mtd))
+ 		return;
+-	parent = mtd_get_master(mtd);
+-	parent_dn = of_node_get(dev_of_node(&parent->dev));
++	parent_dn = of_node_get(mtd_get_of_node(mtd_get_master(mtd)));
+ 	if (!parent_dn)
+ 		return;
+ 
+@@ -618,15 +616,15 @@ static void mtd_check_of_node(struct mtd
+ 
+ 	/* 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-"))
++		if (!of_node_name_prefix(mtd_dn, prefix))
+ 			continue;
+ 
+ 		/* Label have priority. Check that first */
+-		if (of_property_read_string(mtd_dn, "label", &pname)) {
+-			of_property_read_string(mtd_dn, "name", &pname);
++		if (!of_property_read_string(mtd_dn, "label", &pname)) {
++			offset = 0;
++		} else {
++			pname = mtd_dn->name;
+ 			offset = prefix_len;
+ 		}
+ 

target/linux/generic/backport-5.4/417-v6.2-0002-mtd-core-try-to-find-OF-node-for-every-MTD-partition.patch

@@ -0,0 +1,84 @@
+From ddb8cefb7af288950447ca6eeeafb09977dab56f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Tue, 4 Oct 2022 10:37:10 +0200
+Subject: [PATCH] mtd: core: try to find OF node for every MTD partition
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+So far this feature was limited to the top-level "nvmem-cells" node.
+There are multiple parsers creating partitions and subpartitions
+dynamically. Extend that code to handle them too.
+
+This allows finding partition-* node for every MTD (sub)partition.
+
+Random example:
+
+partitions {
+	compatible = "brcm,bcm947xx-cfe-partitions";
+
+	partition-firmware {
+		compatible = "brcm,trx";
+
+		partition-loader {
+		};
+	};
+};
+
+Cc: Christian Marangi <ansuelsmth@gmail.com>
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
+Link: https://lore.kernel.org/linux-mtd/20221004083710.27704-2-zajec5@gmail.com
+---
+ drivers/mtd/mtdcore.c | 18 ++++++------------
+ 1 file changed, 6 insertions(+), 12 deletions(-)
+
+--- a/drivers/mtd/mtdcore.c
++++ b/drivers/mtd/mtdcore.c
+@@ -594,20 +594,22 @@ static void mtd_check_of_node(struct mtd
+ 	struct device_node *partitions, *parent_dn, *mtd_dn = NULL;
+ 	const char *pname, *prefix = "partition-";
+ 	int plen, mtd_name_len, offset, prefix_len;
+-	bool found = false;
+ 
+ 	/* Check if MTD already has a device node */
+ 	if (mtd_get_of_node(mtd))
+ 		return;
+ 
+-	/* Check if a partitions node exist */
+ 	if (!mtd_is_partition(mtd))
+ 		return;
++
+ 	parent_dn = of_node_get(mtd_get_of_node(mtd_get_master(mtd)));
+ 	if (!parent_dn)
+ 		return;
+ 
+-	partitions = of_get_child_by_name(parent_dn, "partitions");
++	if (mtd_is_partition(mtd_get_master(mtd)))
++		partitions = of_node_get(parent_dn);
++	else
++		partitions = of_get_child_by_name(parent_dn, "partitions");
+ 	if (!partitions)
+ 		goto exit_parent;
+ 
+@@ -631,19 +633,11 @@ static void mtd_check_of_node(struct mtd
+ 		plen = strlen(pname) - offset;
+ 		if (plen == mtd_name_len &&
+ 		    !strncmp(mtd->name, pname + offset, plen)) {
+-			found = true;
++			mtd_set_of_node(mtd, mtd_dn);
+ 			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);

target/linux/generic/pending-5.4/480-mtd-set-rootfs-to-be-root-dev.patch

@@ -20,7 +20,7 @@ Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
  #include <linux/nvmem-provider.h>
  
  #include <linux/mtd/mtd.h>
-@@ -762,6 +763,15 @@ int add_mtd_device(struct mtd_info *mtd)
+@@ -754,6 +755,15 @@ int add_mtd_device(struct mtd_info *mtd)
  	   of this try_ nonsense, and no bitching about it
  	   either. :) */
  	__module_get(THIS_MODULE);

target/linux/generic/pending-5.4/495-mtd-core-add-get_mtd_device_by_node.patch

@@ -17,7 +17,7 @@ Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
 
 --- a/drivers/mtd/mtdcore.c
 +++ b/drivers/mtd/mtdcore.c
-@@ -1144,6 +1144,44 @@ out_unlock:
+@@ -1136,6 +1136,44 @@ out_unlock:
  }
  EXPORT_SYMBOL_GPL(get_mtd_device_nm);
  

target/linux/pistachio/patches-5.4/401-mtd-nor-support-mtd-name-from-device-tree.patch

@@ -34,7 +34,7 @@ Signed-off-by: Abhimanyu Vishwakarma <Abhimanyu.Vishwakarma@imgtec.com>
  	mtd->type = MTD_NORFLASH;
 --- a/drivers/mtd/mtdcore.c
 +++ b/drivers/mtd/mtdcore.c
-@@ -842,6 +842,17 @@ out_error:
+@@ -834,6 +834,17 @@ out_error:
   */
  static void mtd_set_dev_defaults(struct mtd_info *mtd)
  {