[PATCH] mtd: Add partition device node to mtd partition devices

[PATCH] mtd: Add partition device node to mtd partition devices

[Uwe Kleine-König]

From: Sascha Hauer <s.hauer@pengutronix.de>

The user visible change here is that mtd partitions get an of_node link
in sysfs.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/mtd/mtdpart.c          | 1 +
 drivers/mtd/ofpart.c           | 1 +
 include/linux/mtd/partitions.h | 1 +
 3 files changed, 3 insertions(+)

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index fccdd49bb964..d0b919ab85c0 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -424,6 +424,7 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
 	slave->mtd.dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) ?
 				&master->dev :
 				master->dev.parent;
+	slave->mtd.dev.of_node = part->of_node;
 
 	slave->mtd._read = part_read;
 	slave->mtd._write = part_write;
diff --git a/drivers/mtd/ofpart.c b/drivers/mtd/ofpart.c
index ede407d6e106..464470122493 100644
--- a/drivers/mtd/ofpart.c
+++ b/drivers/mtd/ofpart.c
@@ -108,6 +108,7 @@ static int parse_ofpart_partitions(struct mtd_info *master,
 
 		parts[i].offset = of_read_number(reg, a_cells);
 		parts[i].size = of_read_number(reg + a_cells, s_cells);
+		parts[i].of_node = pp;
 
 		partname = of_get_property(pp, "label", &len);
 		if (!partname)
diff --git a/include/linux/mtd/partitions.h b/include/linux/mtd/partitions.h
index 70736e1e6c8f..06df1e06b6e0 100644
--- a/include/linux/mtd/partitions.h
+++ b/include/linux/mtd/partitions.h
@@ -41,6 +41,7 @@ struct mtd_partition {
 	uint64_t size;			/* partition size */
 	uint64_t offset;		/* offset within the master MTD space */
 	uint32_t mask_flags;		/* master MTD flags to mask out for this partition */
+	struct device_node *of_node;
 };
 
 #define MTDPART_OFS_RETAIN	(-3)
-- 
2.11.0

Re: [PATCH] mtd: Add partition device node to mtd partition devices

[Boris Brezillon]

+Moritz

On Thu,  9 Feb 2017 11:50:24 +0100
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:

> From: Sascha Hauer <s.hauer@pengutronix.de>
> 
> The user visible change here is that mtd partitions get an of_node link
> in sysfs.

The same patch has already been posted last year [1].
Brian, can we take one of these?

[1]https://patchwork.ozlabs.org/patch/625978/

> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  drivers/mtd/mtdpart.c          | 1 +
>  drivers/mtd/ofpart.c           | 1 +
>  include/linux/mtd/partitions.h | 1 +
>  3 files changed, 3 insertions(+)
> 
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index fccdd49bb964..d0b919ab85c0 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -424,6 +424,7 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
>  	slave->mtd.dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) ?
>  				&master->dev :
>  				master->dev.parent;
> +	slave->mtd.dev.of_node = part->of_node;
>  
>  	slave->mtd._read = part_read;
>  	slave->mtd._write = part_write;
> diff --git a/drivers/mtd/ofpart.c b/drivers/mtd/ofpart.c
> index ede407d6e106..464470122493 100644
> --- a/drivers/mtd/ofpart.c
> +++ b/drivers/mtd/ofpart.c
> @@ -108,6 +108,7 @@ static int parse_ofpart_partitions(struct mtd_info *master,
>  
>  		parts[i].offset = of_read_number(reg, a_cells);
>  		parts[i].size = of_read_number(reg + a_cells, s_cells);
> +		parts[i].of_node = pp;
>  
>  		partname = of_get_property(pp, "label", &len);
>  		if (!partname)
> diff --git a/include/linux/mtd/partitions.h b/include/linux/mtd/partitions.h
> index 70736e1e6c8f..06df1e06b6e0 100644
> --- a/include/linux/mtd/partitions.h
> +++ b/include/linux/mtd/partitions.h
> @@ -41,6 +41,7 @@ struct mtd_partition {
>  	uint64_t size;			/* partition size */
>  	uint64_t offset;		/* offset within the master MTD space */
>  	uint32_t mask_flags;		/* master MTD flags to mask out for this partition */
> +	struct device_node *of_node;
>  };
>  
>  #define MTDPART_OFS_RETAIN	(-3)

Re: [PATCH] mtd: Add partition device node to mtd partition devices

[Uwe Kleine-König]

On Thu, Feb 09, 2017 at 04:34:58PM +0100, Boris Brezillon wrote:
> +Moritz
> 
> On Thu,  9 Feb 2017 11:50:24 +0100
> Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:
> 
> > From: Sascha Hauer <s.hauer@pengutronix.de>
> > 
> > The user visible change here is that mtd partitions get an of_node link
> > in sysfs.
> 
> The same patch has already been posted last year [1].
> Brian, can we take one of these?
> 
> [1]https://patchwork.ozlabs.org/patch/625978/

Moritz' patch is more lame, it even updates the documentation (ok, one
point for Moriz :-) Other than that the only difference is "node" vs.
"of_node" (half a point for Sascha) and the position of the assignment
in mtdpart.c has a different position (another half point for Sascha).

If that would be liked to be seen I can volunteer to create a patch
picking the best from both sources.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

Re: [PATCH] mtd: Add partition device node to mtd partition devices

[Boris Brezillon]

On Thu, 9 Feb 2017 20:39:40 +0100
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:

> On Thu, Feb 09, 2017 at 04:34:58PM +0100, Boris Brezillon wrote:
> > +Moritz
> > 
> > On Thu,  9 Feb 2017 11:50:24 +0100
> > Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:
> >   
> > > From: Sascha Hauer <s.hauer@pengutronix.de>
> > > 
> > > The user visible change here is that mtd partitions get an of_node link
> > > in sysfs.  
> > 
> > The same patch has already been posted last year [1].
> > Brian, can we take one of these?
> > 
> > [1]https://patchwork.ozlabs.org/patch/625978/  
> 
> Moritz' patch is more lame, it even updates the documentation (ok, one
> point for Moriz :-) Other than that the only difference is "node" vs.
> "of_node" (half a point for Sascha) and the position of the assignment
> in mtdpart.c has a different position (another half point for Sascha).
> 
> If that would be liked to be seen I can volunteer to create a patch
> picking the best from both sources.

Sure, you can also add my ack (which I already put on Moritz patch).
BTW, is the of_node link in sysfs the only motivation for this change?
I know Moritz had bigger plans (nvmem blocks on top of MTD devices), and
I also considered advanced stuff (like per-partition ECC config) which
required having a valid ->of_node on slave MTD devices.

Thanks,

Boris

Re: [PATCH] mtd: Add partition device node to mtd partition devices

[Uwe Kleine-König]

Hello Boris,

On Thu, Feb 09, 2017 at 08:59:22PM +0100, Boris Brezillon wrote:
> On Thu, 9 Feb 2017 20:39:40 +0100
> Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:
> 
> > On Thu, Feb 09, 2017 at 04:34:58PM +0100, Boris Brezillon wrote:
> > > +Moritz
> > > 
> > > On Thu,  9 Feb 2017 11:50:24 +0100
> > > Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:
> > >   
> > > > From: Sascha Hauer <s.hauer@pengutronix.de>
> > > > 
> > > > The user visible change here is that mtd partitions get an of_node link
> > > > in sysfs.  
> > > 
> > > The same patch has already been posted last year [1].
> > > Brian, can we take one of these?
> > > 
> > > [1]https://patchwork.ozlabs.org/patch/625978/  
> > 
> > Moritz' patch is more lame, it even updates the documentation (ok, one
> > point for Moriz :-) Other than that the only difference is "node" vs.
> > "of_node" (half a point for Sascha) and the position of the assignment
> > in mtdpart.c has a different position (another half point for Sascha).
> > 
> > If that would be liked to be seen I can volunteer to create a patch
> > picking the best from both sources.
> 
> Sure, you can also add my ack (which I already put on Moritz patch).
> BTW, is the of_node link in sysfs the only motivation for this change?
> I know Moritz had bigger plans (nvmem blocks on top of MTD devices), and
> I also considered advanced stuff (like per-partition ECC config) which
> required having a valid ->of_node on slave MTD devices.

The motivation for Sascha to create this patch and now me to mainline
it, is that we specify some non-volatile state space in dts (to store
for example hardware revision, serial number and mac addresses). See
http://barebox.org/doc/latest/devicetree/bindings/barebox/barebox,state.html
for some details.

For the userspace part we read the dtb, something like

	state {
		compatible = "barebox,state";
		backend = &mtdstatepartition;
		...
	}

, and with the symlink introduced by the patch under discussion it gets
much simpler to find the device file (in /dev) that contains our state
data.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

Re: [PATCH] mtd: Add partition device node to mtd partition devices

[Boris Brezillon]

On Thu, 9 Feb 2017 21:14:04 +0100
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:

> Hello Boris,
> 
> On Thu, Feb 09, 2017 at 08:59:22PM +0100, Boris Brezillon wrote:
> > On Thu, 9 Feb 2017 20:39:40 +0100
> > Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:
> >   
> > > On Thu, Feb 09, 2017 at 04:34:58PM +0100, Boris Brezillon wrote:  
> > > > +Moritz
> > > > 
> > > > On Thu,  9 Feb 2017 11:50:24 +0100
> > > > Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:
> > > >     
> > > > > From: Sascha Hauer <s.hauer@pengutronix.de>
> > > > > 
> > > > > The user visible change here is that mtd partitions get an of_node link
> > > > > in sysfs.    
> > > > 
> > > > The same patch has already been posted last year [1].
> > > > Brian, can we take one of these?
> > > > 
> > > > [1]https://patchwork.ozlabs.org/patch/625978/    
> > > 
> > > Moritz' patch is more lame, it even updates the documentation (ok, one
> > > point for Moriz :-) Other than that the only difference is "node" vs.
> > > "of_node" (half a point for Sascha) and the position of the assignment
> > > in mtdpart.c has a different position (another half point for Sascha).
> > > 
> > > If that would be liked to be seen I can volunteer to create a patch
> > > picking the best from both sources.  
> > 
> > Sure, you can also add my ack (which I already put on Moritz patch).
> > BTW, is the of_node link in sysfs the only motivation for this change?
> > I know Moritz had bigger plans (nvmem blocks on top of MTD devices), and
> > I also considered advanced stuff (like per-partition ECC config) which
> > required having a valid ->of_node on slave MTD devices.  
> 
> The motivation for Sascha to create this patch and now me to mainline
> it, is that we specify some non-volatile state space in dts (to store
> for example hardware revision, serial number and mac addresses). See
> http://barebox.org/doc/latest/devicetree/bindings/barebox/barebox,state.html
> for some details.
> 
> For the userspace part we read the dtb, something like
> 
> 	state {
> 		compatible = "barebox,state";
> 		backend = &mtdstatepartition;
> 		...
> 	}
> 
> , and with the symlink introduced by the patch under discussion it gets
> much simpler to find the device file (in /dev) that contains our state
> data.

Okay. Looks like an advanced nvmem [1] implementation. Anyway, having
the of_node populated for MTD partition devs sounds reasonable, no
matter the reason you need that for.

[1]http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/nvmem/nvmem.txt

Re: [PATCH] mtd: Add partition device node to mtd partition devices

[Brian Norris]

On Thu, Feb 09, 2017 at 11:50:24AM +0100, Uwe Kleine-König wrote:
> From: Sascha Hauer <s.hauer@pengutronix.de>
> 
> The user visible change here is that mtd partitions get an of_node link
> in sysfs.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Appled to l2-mtd.git