* [PATCH 1/2] dt-bindings: mtd: partitions: support marking root device partition
@ 2022-10-19 11:48 Rafał Miłecki
2022-10-19 11:50 ` [PATCH 2/2] mtd: core: set ROOT_DEV for partitions marked as root devices in DT Rafał Miłecki
0 siblings, 1 reply; 4+ messages in thread
From: Rafał Miłecki @ 2022-10-19 11:48 UTC (permalink / raw)
To: Miquel Raynal, Richard Weinberger, Vignesh Raghavendra,
Rob Herring, Krzysztof Kozlowski
Cc: Mikhail Zhilkin, Christian Marangi, Wolfram Sang,
Chaitanya Kulkarni, Martin K . Petersen, Jens Axboe,
Andrew Morton, linux-mtd, devicetree, linux-kernel,
Rafał Miłecki
From: Rafał Miłecki <rafal@milecki.pl>
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,root-device" property to mark
correct flash partition.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
.../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..e627085df4fc 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,root-device;
};
};
diff --git a/Documentation/devicetree/bindings/mtd/partitions/partition.yaml b/Documentation/devicetree/bindings/mtd/partitions/partition.yaml
index f1a02d840b12..671906acf1bd 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,root-device:
+ description: Marks partition that is a root device with filesystem to mount
+ and boot user space from
+
if:
not:
required: [ reg ]
--
2.34.1
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^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 2/2] mtd: core: set ROOT_DEV for partitions marked as root devices in DT
2022-10-19 11:48 [PATCH 1/2] dt-bindings: mtd: partitions: support marking root device partition Rafał Miłecki
@ 2022-10-19 11:50 ` Rafał Miłecki
2022-10-19 11:53 ` Rafał Miłecki
0 siblings, 1 reply; 4+ messages in thread
From: Rafał Miłecki @ 2022-10-19 11:50 UTC (permalink / raw)
To: Miquel Raynal, Richard Weinberger, Vignesh Raghavendra,
Rob Herring, Krzysztof Kozlowski
Cc: Mikhail Zhilkin, Christian Marangi, Wolfram Sang,
Chaitanya Kulkarni, Martin K . Petersen, Jens Axboe,
Andrew Morton, linux-mtd, devicetree, linux-kernel,
Rafał Miłecki
From: Rafał Miłecki <rafal@milecki.pl>
This adds support for "linux,root-device" binding that is used to mark
root device MTD partition. 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>
---
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
______________________________________________________
Linux MTD discussion mailing list
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^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH 2/2] mtd: core: set ROOT_DEV for partitions marked as root devices in DT
2022-10-19 11:50 ` [PATCH 2/2] mtd: core: set ROOT_DEV for partitions marked as root devices in DT Rafał Miłecki
@ 2022-10-19 11:53 ` Rafał Miłecki
2022-10-21 1:50 ` Rob Herring
0 siblings, 1 reply; 4+ messages in thread
From: Rafał Miłecki @ 2022-10-19 11:53 UTC (permalink / raw)
To: Miquel Raynal, Richard Weinberger, Vignesh Raghavendra,
Rob Herring, Krzysztof Kozlowski
Cc: Mikhail Zhilkin, Christian Marangi, Wolfram Sang,
Chaitanya Kulkarni, Martin K . Petersen, Jens Axboe,
Andrew Morton, linux-mtd, devicetree, linux-kernel,
Rafał Miłecki
On 19.10.2022 13:50, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@milecki.pl>
>
> This adds support for "linux,root-device" binding that is used to mark
> root device MTD partition. 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>
> ---
> 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)) {
I forgot to re-do "format-patch" after "commit --amend".
s/linux,rootfs/linux,root-device/
I'll fix that in V2 after giving this patchset some time to review.
> + 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
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH 2/2] mtd: core: set ROOT_DEV for partitions marked as root devices in DT
2022-10-19 11:53 ` Rafał Miłecki
@ 2022-10-21 1:50 ` Rob Herring
0 siblings, 0 replies; 4+ messages in thread
From: Rob Herring @ 2022-10-21 1:50 UTC (permalink / raw)
To: Rafał Miłecki
Cc: Miquel Raynal, Richard Weinberger, Vignesh Raghavendra,
Krzysztof Kozlowski, Mikhail Zhilkin, Christian Marangi,
Wolfram Sang, Chaitanya Kulkarni, Martin K . Petersen,
Jens Axboe, Andrew Morton, linux-mtd, devicetree, linux-kernel,
Rafał Miłecki
On Wed, Oct 19, 2022 at 01:53:15PM +0200, Rafał Miłecki wrote:
> On 19.10.2022 13:50, Rafał Miłecki wrote:
> > From: Rafał Miłecki <rafal@milecki.pl>
> >
> > This adds support for "linux,root-device" binding that is used to mark
> > root device MTD partition. 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>
> > ---
> > 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)) {
>
> I forgot to re-do "format-patch" after "commit --amend".
> s/linux,rootfs/linux,root-device/
It's really the filesystem you are tagging, not a device, so I think
'linux,rootfs' is better.
Rob
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2022-10-19 11:48 [PATCH 1/2] dt-bindings: mtd: partitions: support marking root device partition Rafał Miłecki
2022-10-19 11:50 ` [PATCH 2/2] mtd: core: set ROOT_DEV for partitions marked as root devices in DT Rafał Miłecki
2022-10-19 11:53 ` Rafał Miłecki
2022-10-21 1:50 ` Rob Herring
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