[PATCH for-4.4] mtd: nand: assign reasonable default name for NAND drivers

[PATCH for-4.4] mtd: nand: assign reasonable default name for NAND drivers

[Brian Norris]

Commits such as commit 853f1c58c4b2 ("mtd: nand: omap2: show parent
device structure in sysfs") attempt to rely on the core MTD code to set
the MTD name based on the parent device. However, nand_base tries to set
a different default name according to the flash name (e.g., extracted
from the ONFI parameter page), which means NAND drivers will never make
use of the MTD defaults. This is not the intention of commit
853f1c58c4b2.

This results in problems when trying to use the cmdline partition
parser, since the MTD name is different than expected. Let's fix this by
providing a default NAND name, where possible.

Note that this is not really a great default name in the long run, since
this means that if there are multiple MTDs attached to the same
controller device, they will have the same name. But that is an existing
issue and requires future work on a better controller vs. flash chip
abstraction to fix properly.

Reported-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Frans Klaver <fransklaver@gmail.com>
---
This patch is needed in additon to commit 472b444eef93 ("mtd: fix cmdlinepart
parser, early naming for auto-filled MTD") to fix Heiko's reported problem. At
this point, I'm not sure if this should be targeted toward late 4.4 or for 4.5.
It's a 4.4 regresssion, but a very small one. And I'm not sure if this will
have wide enough impact that it should be given a longer time to be reviewed
and tested. We can always send it to -stable later, if it's really needed.

 drivers/mtd/nand/nand_base.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index ece544efccc3..9f169566fba4 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -3826,6 +3826,9 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
 	if (!type)
 		type = nand_flash_ids;
 
+	if (!mtd->name && mtd->dev.parent)
+		mtd->name = dev_name(mtd->dev.parent);
+
 	for (; type->name != NULL; type++) {
 		if (is_full_id_nand(type)) {
 			if (find_full_id_nand(mtd, chip, type, id_data, &busw))
-- 
2.6.0.rc2.230.g3dd15c0

Re: [PATCH for-4.4] mtd: nand: assign reasonable default name for NAND drivers

[Boris Brezillon]

Hi Brian,

On Mon,  4 Jan 2016 11:11:03 -0800
Brian Norris <computersforpeace@gmail.com> wrote:

> Commits such as commit 853f1c58c4b2 ("mtd: nand: omap2: show parent
> device structure in sysfs") attempt to rely on the core MTD code to set
> the MTD name based on the parent device. However, nand_base tries to set
> a different default name according to the flash name (e.g., extracted
> from the ONFI parameter page), which means NAND drivers will never make
> use of the MTD defaults. This is not the intention of commit
> 853f1c58c4b2.
> 
> This results in problems when trying to use the cmdline partition
> parser, since the MTD name is different than expected. Let's fix this by
> providing a default NAND name, where possible.
> 
> Note that this is not really a great default name in the long run, since
> this means that if there are multiple MTDs attached to the same
> controller device, they will have the same name. But that is an existing
> issue and requires future work on a better controller vs. flash chip
> abstraction to fix properly.

Yep, and IMHO, the chip numbering currently in use in most NAND
controller drivers is not the best solution either. We should somehow
find a way to describe the mtd id using something like:

mtd-id: <nand-controller-id>@<cs-line>
nand-controller-id: <nand-controller-ip-name>-<ip-address>

Anyway, let's discuss that after the nand-chip <-> nand-controller
separation rework.

> 
> Reported-by: Heiko Schocher <hs@denx.de>
> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> Cc: Heiko Schocher <hs@denx.de>
> Cc: Frans Klaver <fransklaver@gmail.com>
> ---
> This patch is needed in additon to commit 472b444eef93 ("mtd: fix cmdlinepart
> parser, early naming for auto-filled MTD") to fix Heiko's reported problem. At
> this point, I'm not sure if this should be targeted toward late 4.4 or for 4.5.
> It's a 4.4 regresssion, but a very small one. And I'm not sure if this will
> have wide enough impact that it should be given a longer time to be reviewed
> and tested. We can always send it to -stable later, if it's really needed.
> 
>  drivers/mtd/nand/nand_base.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index ece544efccc3..9f169566fba4 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -3826,6 +3826,9 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
>  	if (!type)
>  		type = nand_flash_ids;
>  
> +	if (!mtd->name && mtd->dev.parent)
> +		mtd->name = dev_name(mtd->dev.parent);
> +

Just nitpicking, but I think this would be better placed in
nand_set_defaults() or in nand_scan_ident() before nand_get_flash_type()
call.

Anyway,

Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

>  	for (; type->name != NULL; type++) {
>  		if (is_full_id_nand(type)) {
>  			if (find_full_id_nand(mtd, chip, type, id_data, &busw))

Best Regards,

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Re: [PATCH for-4.4] mtd: nand: assign reasonable default name for NAND drivers

[Heiko Schocher]

Hello Brian,

Am 04.01.2016 um 20:11 schrieb Brian Norris:
> Commits such as commit 853f1c58c4b2 ("mtd: nand: omap2: show parent
> device structure in sysfs") attempt to rely on the core MTD code to set
> the MTD name based on the parent device. However, nand_base tries to set
> a different default name according to the flash name (e.g., extracted
> from the ONFI parameter page), which means NAND drivers will never make
> use of the MTD defaults. This is not the intention of commit
> 853f1c58c4b2.
>
> This results in problems when trying to use the cmdline partition
> parser, since the MTD name is different than expected. Let's fix this by
> providing a default NAND name, where possible.
>
> Note that this is not really a great default name in the long run, since
> this means that if there are multiple MTDs attached to the same
> controller device, they will have the same name. But that is an existing
> issue and requires future work on a better controller vs. flash chip
> abstraction to fix properly.
>
> Reported-by: Heiko Schocher <hs@denx.de>
> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> Cc: Heiko Schocher <hs@denx.de>
> Cc: Frans Klaver <fransklaver@gmail.com>
> ---
> This patch is needed in additon to commit 472b444eef93 ("mtd: fix cmdlinepart
> parser, early naming for auto-filled MTD") to fix Heiko's reported problem. At
> this point, I'm not sure if this should be targeted toward late 4.4 or for 4.5.
> It's a 4.4 regresssion, but a very small one. And I'm not sure if this will
> have wide enough impact that it should be given a longer time to be reviewed
> and tested. We can always send it to -stable later, if it's really needed.

Ok... but I wonder if nobody have the same problems as I ...

>   drivers/mtd/nand/nand_base.c | 3 +++
>   1 file changed, 3 insertions(+)

Thanks!

works for me, so:

Tested-by: Heiko Schocher <hs@denx.de>

bye,
Heiko
>
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index ece544efccc3..9f169566fba4 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -3826,6 +3826,9 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
>   	if (!type)
>   		type = nand_flash_ids;
>
> +	if (!mtd->name && mtd->dev.parent)
> +		mtd->name = dev_name(mtd->dev.parent);
> +
>   	for (; type->name != NULL; type++) {
>   		if (is_full_id_nand(type)) {
>   			if (find_full_id_nand(mtd, chip, type, id_data, &busw))
>

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

Re: [for-4.4] mtd: nand: assign reasonable default name for NAND drivers

[Sørensen, Stefan]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 863 bytes --]

Hi Brian,

On Mon, 2016-01-04 at 11:11 -0800, Brian Norris wrote:
> This patch is needed in additon to commit 472b444eef93 ("mtd: fix 
> cmdlinepart parser, early naming for auto-filled MTD") to fix Heiko's
> reported problem. At this point, I'm not sure if this should be
> targeted toward late 4.4 or for 4.5. It's a 4.4 regresssion, but a
> very small one. And I'm not sure if this will have wide enough
> impact that it should be given a longer time to be reviewed and
> tested. We can always send it to -stable later, if it's really
> needed.

I have boards that will not boot 4.4 without these two patches, so I
hope to see it go in to 4.4.1 (I guess it is too late for 4.4).

Regards, 
 Stefanÿôèº{.nÇ+‰·Ÿ®‰­†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a­¢f£¢·hšïêÿ‘êçz_è®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨è­Ú&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥

Re: [for-4.4] mtd: nand: assign reasonable default name for NAND drivers

[Sørensen, Stefan]

Hi Brian,

On Mon, 2016-01-04 at 11:11 -0800, Brian Norris wrote:
> This patch is needed in additon to commit 472b444eef93 ("mtd: fix 
> cmdlinepart parser, early naming for auto-filled MTD") to fix Heiko's
> reported problem. At this point, I'm not sure if this should be
> targeted toward late 4.4 or for 4.5. It's a 4.4 regresssion, but a
> very small one. And I'm not sure if this will have wide enough
> impact that it should be given a longer time to be reviewed and
> tested. We can always send it to -stable later, if it's really
> needed.

I have boards that will not boot 4.4 without these two patches, so I
hope to see it go in to 4.4.1 (I guess it is too late for 4.4).

Regards, 
 Stefan

Re: [PATCH for-4.4] mtd: nand: assign reasonable default name for NAND drivers

[Brian Norris]

Hi Boris,

On Mon, Jan 04, 2016 at 09:31:02PM +0100, Boris Brezillon wrote:
> On Mon,  4 Jan 2016 11:11:03 -0800
> Brian Norris <computersforpeace@gmail.com> wrote:
> 
> > Commits such as commit 853f1c58c4b2 ("mtd: nand: omap2: show parent
> > device structure in sysfs") attempt to rely on the core MTD code to set
> > the MTD name based on the parent device. However, nand_base tries to set
> > a different default name according to the flash name (e.g., extracted
> > from the ONFI parameter page), which means NAND drivers will never make
> > use of the MTD defaults. This is not the intention of commit
> > 853f1c58c4b2.
> > 
> > This results in problems when trying to use the cmdline partition
> > parser, since the MTD name is different than expected. Let's fix this by
> > providing a default NAND name, where possible.
> > 
> > Note that this is not really a great default name in the long run, since
> > this means that if there are multiple MTDs attached to the same
> > controller device, they will have the same name. But that is an existing
> > issue and requires future work on a better controller vs. flash chip
> > abstraction to fix properly.
> 
> Yep, and IMHO, the chip numbering currently in use in most NAND
> controller drivers is not the best solution either. We should somehow
> find a way to describe the mtd id using something like:
> 
> mtd-id: <nand-controller-id>@<cs-line>
> nand-controller-id: <nand-controller-ip-name>-<ip-address>

Maybe dots ('.') instead of '@'? But otherwise, seems somewhat
reasonable. Maybe this could just be something like:

	dev_name(mtd->dev.parent) + "." + chip_select

> Anyway, let's discuss that after the nand-chip <-> nand-controller
> separation rework.

Sure.

> > Reported-by: Heiko Schocher <hs@denx.de>
> > Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> > Cc: Heiko Schocher <hs@denx.de>
> > Cc: Frans Klaver <fransklaver@gmail.com>
> > ---
> > This patch is needed in additon to commit 472b444eef93 ("mtd: fix cmdlinepart
> > parser, early naming for auto-filled MTD") to fix Heiko's reported problem. At
> > this point, I'm not sure if this should be targeted toward late 4.4 or for 4.5.
> > It's a 4.4 regresssion, but a very small one. And I'm not sure if this will
> > have wide enough impact that it should be given a longer time to be reviewed
> > and tested. We can always send it to -stable later, if it's really needed.
> > 
> >  drivers/mtd/nand/nand_base.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> > index ece544efccc3..9f169566fba4 100644
> > --- a/drivers/mtd/nand/nand_base.c
> > +++ b/drivers/mtd/nand/nand_base.c
> > @@ -3826,6 +3826,9 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
> >  	if (!type)
> >  		type = nand_flash_ids;
> >  
> > +	if (!mtd->name && mtd->dev.parent)
> > +		mtd->name = dev_name(mtd->dev.parent);
> > +
> 
> Just nitpicking, but I think this would be better placed in
> nand_set_defaults() or in nand_scan_ident() before nand_get_flash_type()
> call.

Hmm, nand_set_defaults() would probably be better. I'll resend this and
defer it to 4.5 (and 4.4.x).

> Anyway,
> 
> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Thanks,
Brian