From: Rafał Miłecki <[email protected]>
Linux needs to know what to use as root device. On embedded devices with
flash the only common way to specify that is cmdline & root= parameter.
That solution works with U-Boot which is Linux & cmdline aware but isn't
available with all market bootloaders. Also that method is fragile:
1. Requires specific probing order on multi-flash devices
2. Uses hardcoded partitions indexes
A lot of devices use different partitioning methods. It may be
"fixed-partitions" or some dynamic partitioning (e.g. based on parts
table). For such cases allow "linux,rootfs" property to mark correct
flash partition.
Signed-off-by: Rafał Miłecki <[email protected]>
---
V2: Use "linux,rootfs" as more accurate. Thanks Rob.
---
.../devicetree/bindings/mtd/partitions/fixed-partitions.yaml | 1 +
.../devicetree/bindings/mtd/partitions/partition.yaml | 4 ++++
2 files changed, 5 insertions(+)
diff --git a/Documentation/devicetree/bindings/mtd/partitions/fixed-partitions.yaml b/Documentation/devicetree/bindings/mtd/partitions/fixed-partitions.yaml
index ad3ccd250802..d66a6e3bcb56 100644
--- a/Documentation/devicetree/bindings/mtd/partitions/fixed-partitions.yaml
+++ b/Documentation/devicetree/bindings/mtd/partitions/fixed-partitions.yaml
@@ -84,6 +84,7 @@ examples:
partition@0 {
label = "filesystem";
reg = <0x00000000 0x1 0x00000000>;
+ linux,rootfs;
};
};
diff --git a/Documentation/devicetree/bindings/mtd/partitions/partition.yaml b/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
index f1a02d840b12..a25cd23a34c0 100644
--- a/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
+++ b/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
@@ -52,6 +52,10 @@ properties:
immune to paired-pages corruptions
type: boolean
+ linux,rootfs:
+ description: Marks partition that contains root filesystem to mount and boot
+ user space from
+
if:
not:
required: [ reg ]
--
2.34.1
From: Rafał Miłecki <[email protected]>
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 <[email protected]>
---
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
Hi Rafał,
I love your patch! Yet something to improve:
[auto build test ERROR on mtd/mtd/next]
[also build test ERROR on mtd/mtd/fixes robh/for-next linus/master v6.1-rc1 next-20221021]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Rafa-Mi-ecki/dt-bindings-mtd-partitions-support-marking-rootfs-partition/20221021-140227
base: https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next
patch link: https://lore.kernel.org/r/20221021060051.2508-2-zajec5%40gmail.com
patch subject: [PATCH V2 2/2] mtd: core: set ROOT_DEV for partitions marked as rootfs in DT
config: powerpc-allmodconfig
compiler: powerpc-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/354cb0f2c01431932e04ea678765941b3fac1c8a
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Rafa-Mi-ecki/dt-bindings-mtd-partitions-support-marking-rootfs-partition/20221021-140227
git checkout 354cb0f2c01431932e04ea678765941b3fac1c8a
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>, old ones prefixed by <<):
>> ERROR: modpost: "ROOT_DEV" [drivers/mtd/mtd.ko] undefined!
--
0-DAY CI Kernel Test Service
https://01.org/lkp
Hi Rafał,
I love your patch! Yet something to improve:
[auto build test ERROR on mtd/mtd/next]
[also build test ERROR on mtd/mtd/fixes robh/for-next linus/master v6.1-rc1 next-20221021]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Rafa-Mi-ecki/dt-bindings-mtd-partitions-support-marking-rootfs-partition/20221021-140227
base: https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next
patch link: https://lore.kernel.org/r/20221021060051.2508-2-zajec5%40gmail.com
patch subject: [PATCH V2 2/2] mtd: core: set ROOT_DEV for partitions marked as rootfs in DT
config: i386-randconfig-a015-20221017
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/354cb0f2c01431932e04ea678765941b3fac1c8a
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Rafa-Mi-ecki/dt-bindings-mtd-partitions-support-marking-rootfs-partition/20221021-140227
git checkout 354cb0f2c01431932e04ea678765941b3fac1c8a
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>, old ones prefixed by <<):
>> ERROR: modpost: "ROOT_DEV" [drivers/mtd/mtd.ko] undefined!
--
0-DAY CI Kernel Test Service
https://01.org/lkp