[PATCH V2 2/2] mtd: core: set ROOT_DEV for partitions marked as rootfs in DT

Rafał Miłecki
2022-10-21T06:01:09Z

From: Rafał Miłecki <rafal@milecki.pl>

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>
---
V2: Use "linux,rootfs" as more accurate. Thanks Rob.
---
drivers/mtd/mtdcore.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 07249af4f890..034b06aff660 100644
--- 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>
@@ -735,6 +736,12 @@ 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)) {
+ pr_info("mtd: setting mtd%d (%s) as root device\n", mtd->index, mtd->name);
+ ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
+ }
+
/* 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
--
2.34.1