kernel: backport support for "linux,rootfs" in DT

This DT property allows marking flash partition that Linux should use as
a root device. It's useful for devices that don't use U-Boot and cmdline
parser for partitioning. It may be used with "fixed-partitions" or some
dynamic partitioning based on flash content.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit d33e49857e3ad76586ebe55334996b15cd45ca1b)

7 files changed, 93 insertions, 49 deletions

diff --git a/target/linux/generic/backport-5.10/418-v6.2-mtd-core-set-ROOT_DEV-for-partitions-marked-as-rootf.patch b/target/linux/generic/backport-5.10/418-v6.2-mtd-core-set-ROOT_DEV-for-partitions-marked-as-rootf.patch
new file mode 100644
index 0000000000..ac5b438e6d
--- /dev/null
+++ b/target/linux/generic/backport-5.10/418-v6.2-mtd-core-set-ROOT_DEV-for-partitions-marked-as-rootf.patch
@@ -0,0 +1,47 @@
+From 26422ac78e9d8767bd4aabfbae616b15edbf6a1b Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Sat, 22 Oct 2022 23:13:18 +0200
+Subject: [PATCH] mtd: core: set ROOT_DEV for partitions marked as rootfs in DT
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This adds support for "linux,rootfs" binding that is used to mark flash
+partition containing rootfs. It's useful for devices using device tree
+that don't have bootloader passing root info in cmdline.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
+Link: https://lore.kernel.org/linux-mtd/20221022211318.32009-2-zajec5@gmail.com
+---
+ drivers/mtd/mtdcore.c | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+--- a/drivers/mtd/mtdcore.c
++++ b/drivers/mtd/mtdcore.c
+@@ -28,6 +28,7 @@
+ #include <linux/leds.h>
+ #include <linux/debugfs.h>
+ #include <linux/nvmem-provider.h>
++#include <linux/root_dev.h>
+ 
+ #include <linux/mtd/mtd.h>
+ #include <linux/mtd/partitions.h>
+@@ -743,6 +744,17 @@ int add_mtd_device(struct mtd_info *mtd)
+ 		not->add(mtd);
+ 
+ 	mutex_unlock(&mtd_table_mutex);
++
++	if (of_find_property(mtd_get_of_node(mtd), "linux,rootfs", NULL)) {
++		if (IS_BUILTIN(CONFIG_MTD)) {
++			pr_info("mtd: setting mtd%d (%s) as root device\n", mtd->index, mtd->name);
++			ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
++		} else {
++			pr_warn("mtd: can't set mtd%d (%s) as root device - mtd must be builtin\n",
++				mtd->index, mtd->name);
++		}
++	}
++
+ 	/* We _know_ we aren't being removed, because
+ 	   our caller is still holding us here. So none
+ 	   of this try_ nonsense, and no bitching about it
diff --git a/target/linux/generic/hack-5.10/402-mtd-blktrans-call-add-disks-after-mtd-device.patch b/target/linux/generic/hack-5.10/402-mtd-blktrans-call-add-disks-after-mtd-device.patch
index a650320cd0..dc342da831 100644
--- a/target/linux/generic/hack-5.10/402-mtd-blktrans-call-add-disks-after-mtd-device.patch
+++ b/target/linux/generic/hack-5.10/402-mtd-blktrans-call-add-disks-after-mtd-device.patch
@@ -69,7 +69,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  	unsigned long flags;
 --- a/drivers/mtd/mtdcore.c
 +++ b/drivers/mtd/mtdcore.c
-@@ -31,6 +31,7 @@
+@@ -32,6 +32,7 @@
  
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/partitions.h>
@@ -77,7 +77,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  
  #include "mtdcore.h"
  
-@@ -916,6 +917,8 @@ int mtd_device_parse_register(struct mtd
+@@ -928,6 +929,8 @@ int mtd_device_parse_register(struct mtd
  		register_reboot_notifier(&mtd->reboot_notifier);
  	}
  
diff --git a/target/linux/generic/hack-5.10/420-mtd-set-rootfs-to-be-root-dev.patch b/target/linux/generic/hack-5.10/420-mtd-set-rootfs-to-be-root-dev.patch
deleted file mode 100644
index a70d8af4c2..0000000000
--- a/target/linux/generic/hack-5.10/420-mtd-set-rootfs-to-be-root-dev.patch
+++ /dev/null
@@ -1,39 +0,0 @@
-From: Gabor Juhos <juhosg@openwrt.org>
-Subject: kernel/3.1[02]: move MTD root device setup code to mtdcore
-
-The current code only allows to automatically set
-root device on MTD partitions. Move the code to MTD
-core to allow to use it with all MTD devices.
-
-Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
----
- drivers/mtd/mtdcore.c | 10 ++++++++++
- 1 file changed, 10 insertions(+)
-
---- a/drivers/mtd/mtdcore.c
-+++ b/drivers/mtd/mtdcore.c
-@@ -27,6 +27,7 @@
- #include <linux/reboot.h>
- #include <linux/leds.h>
- #include <linux/debugfs.h>
-+#include <linux/root_dev.h>
- #include <linux/nvmem-provider.h>
- 
- #include <linux/mtd/mtd.h>
-@@ -759,6 +760,16 @@ int add_mtd_device(struct mtd_info *mtd)
- 	   of this try_ nonsense, and no bitching about it
- 	   either. :) */
- 	__module_get(THIS_MODULE);
-+
-+	if (!strcmp(mtd->name, "rootfs") &&
-+	    IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV) &&
-+	    ROOT_DEV == 0) {
-+		unsigned int index = mtd->index;
-+		pr_notice("mtd: device %d (%s) set to be root filesystem\n",
-+			  mtd->index, mtd->name);
-+		ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, index);
-+	}
-+
- 	return 0;
- 
- fail_nvmem_add:
diff --git a/target/linux/generic/hack-5.10/420-mtd-support-OpenWrt-s-MTD_ROOTFS_ROOT_DEV.patch b/target/linux/generic/hack-5.10/420-mtd-support-OpenWrt-s-MTD_ROOTFS_ROOT_DEV.patch
new file mode 100644
index 0000000000..89ac3cb9fe
--- /dev/null
+++ b/target/linux/generic/hack-5.10/420-mtd-support-OpenWrt-s-MTD_ROOTFS_ROOT_DEV.patch
@@ -0,0 +1,24 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Mon, 7 Nov 2022 23:48:24 +0100
+Subject: [PATCH] mtd: support OpenWrt's MTD_ROOTFS_ROOT_DEV
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+This allows setting ROOT_DEV to MTD partition named "rootfs".
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+
+--- a/drivers/mtd/mtdcore.c
++++ b/drivers/mtd/mtdcore.c
+@@ -756,7 +756,8 @@ int add_mtd_device(struct mtd_info *mtd)
+ 
+ 	mutex_unlock(&mtd_table_mutex);
+ 
+-	if (of_find_property(mtd_get_of_node(mtd), "linux,rootfs", NULL)) {
++	if (of_find_property(mtd_get_of_node(mtd), "linux,rootfs", NULL) ||
++	    (IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV) && !strcmp(mtd->name, "rootfs") && ROOT_DEV == 0)) {
+ 		if (IS_BUILTIN(CONFIG_MTD)) {
+ 			pr_info("mtd: setting mtd%d (%s) as root device\n", mtd->index, mtd->name);
+ 			ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
diff --git a/target/linux/generic/hack-5.10/421-mtd-fix-squashfs-root-on-targets-with-CONFIG_FIT_PAR.patch b/target/linux/generic/hack-5.10/421-mtd-fix-squashfs-root-on-targets-with-CONFIG_FIT_PAR.patch
index 2f7da2aaba..1cd0efd624 100644
--- a/target/linux/generic/hack-5.10/421-mtd-fix-squashfs-root-on-targets-with-CONFIG_FIT_PAR.patch
+++ b/target/linux/generic/hack-5.10/421-mtd-fix-squashfs-root-on-targets-with-CONFIG_FIT_PAR.patch
@@ -7,13 +7,25 @@ Fix assumption about the block device index
 
 --- a/drivers/mtd/mtdcore.c
 +++ b/drivers/mtd/mtdcore.c
-@@ -767,6 +767,9 @@ int add_mtd_device(struct mtd_info *mtd)
- 		unsigned int index = mtd->index;
- 		pr_notice("mtd: device %d (%s) set to be root filesystem\n",
- 			  mtd->index, mtd->name);
+@@ -758,12 +758,18 @@ int add_mtd_device(struct mtd_info *mtd)
+ 
+ 	if (of_find_property(mtd_get_of_node(mtd), "linux,rootfs", NULL) ||
+ 	    (IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV) && !strcmp(mtd->name, "rootfs") && ROOT_DEV == 0)) {
++		unsigned int index = mtd->index;
++
 +#ifdef CONFIG_FIT_PARTITION
 +		index <<= 2;
 +#endif
- 		ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, index);
++
+ 		if (IS_BUILTIN(CONFIG_MTD)) {
+-			pr_info("mtd: setting mtd%d (%s) as root device\n", mtd->index, mtd->name);
+-			ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
++			pr_info("mtd: setting mtd%d (%s) as root device\n", index, mtd->name);
++			ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, index);
+ 		} else {
+ 			pr_warn("mtd: can't set mtd%d (%s) as root device - mtd must be builtin\n",
+-				mtd->index, mtd->name);
++				index, mtd->name);
+ 		}
  	}
  
diff --git a/target/linux/generic/pending-5.10/402-mtd-spi-nor-write-support-for-minor-aligned-partitions.patch b/target/linux/generic/pending-5.10/402-mtd-spi-nor-write-support-for-minor-aligned-partitions.patch
index 53d5637e41..498876ef2f 100644
--- a/target/linux/generic/pending-5.10/402-mtd-spi-nor-write-support-for-minor-aligned-partitions.patch
+++ b/target/linux/generic/pending-5.10/402-mtd-spi-nor-write-support-for-minor-aligned-partitions.patch
@@ -80,7 +80,7 @@ Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
 
 --- a/drivers/mtd/mtdcore.c
 +++ b/drivers/mtd/mtdcore.c
-@@ -163,6 +163,15 @@ static ssize_t mtd_erasesize_show(struct
+@@ -164,6 +164,15 @@ static ssize_t mtd_erasesize_show(struct
  }
  static DEVICE_ATTR(erasesize, S_IRUGO, mtd_erasesize_show, NULL);
  
@@ -96,7 +96,7 @@ Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
  static ssize_t mtd_writesize_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
-@@ -312,6 +321,7 @@ static struct attribute *mtd_attrs[] = {
+@@ -313,6 +322,7 @@ static struct attribute *mtd_attrs[] = {
  	&dev_attr_flags.attr,
  	&dev_attr_size.attr,
  	&dev_attr_erasesize.attr,
diff --git a/target/linux/generic/pending-5.10/495-mtd-core-add-get_mtd_device_by_node.patch b/target/linux/generic/pending-5.10/495-mtd-core-add-get_mtd_device_by_node.patch
index 8b40caa1fe..ac770b1394 100644
--- a/target/linux/generic/pending-5.10/495-mtd-core-add-get_mtd_device_by_node.patch
+++ b/target/linux/generic/pending-5.10/495-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
-@@ -1139,6 +1139,44 @@ out_unlock:
+@@ -1151,6 +1151,44 @@ out_unlock:
  }
  EXPORT_SYMBOL_GPL(get_mtd_device_nm);