[U-Boot-Users] NAND and JFFS2

[U-Boot-Users] NAND and JFFS2

[Matt Gessner]

Hi, all,

I'm using 1.2.0 on an AT91RM9200, along with linux 2.6.20-2 w/ patches
from Maxim.

I'm looking for info on how compatible the JFFS2 stuff is between u-boot
and linux.

When I mount a partition (I have JFFS2 debugging turned on in the
kernel), I get two kinds of error messages:

	"jffs2_check_nand_cleanmarker(): Cleanmarker node not detected
in block at X"
	"OOB at X was ...."  (lots of data, not all FF)
	"CLEANMARKER node found at X has totlen 0xc != normal 0x0"

OR

	"jffs2_check_nand_cleanmarker(): Cleanmarker node not detected
in block at X"
	"OOB at X was ...."  (lots of FF)

I'm wondering if anyone can point me to what I'm doing wrong.

I have 3 partitions: boot, backup and config, which I made using
mtdparts.  When I work with my nand device, I use 'nand erase clean',
which I thought would write the nand clean markers.  The jffs2 is
expecting nand clean markers at every 4K (0x1000) bytes.

I'm wondering if my mkfs.jffs2 command is wrong, or if my use of nand
erase is wrong, or if I need to specify something in either the kernel
or the u-boot config is wrong.

Any pointers are appreciated.

Thanks for everyone's hard work making u-boot a great tool.

Regards,

Matt G.

[U-Boot-Users] NAND and JFFS2

[Ulf Samuelsson]

Matt Gessner skrev:
> Hi, all,
> 
> I'm using 1.2.0 on an AT91RM9200, along with linux 2.6.20-2 w/ patches
> from Maxim.
> 
> I'm looking for info on how compatible the JFFS2 stuff is between u-boot
> and linux.
> 
> When I mount a partition (I have JFFS2 debugging turned on in the
> kernel), I get two kinds of error messages:
> 
> 	"jffs2_check_nand_cleanmarker(): Cleanmarker node not detected
> in block at X"
> 	"OOB at X was ...."  (lots of data, not all FF)
> 	"CLEANMARKER node found at X has totlen 0xc != normal 0x0"
> 
> OR
> 
> 	"jffs2_check_nand_cleanmarker(): Cleanmarker node not detected
> in block at X"
> 	"OOB at X was ...."  (lots of FF)
> 
> I'm wondering if anyone can point me to what I'm doing wrong.
> 
> I have 3 partitions: boot, backup and config, which I made using
> mtdparts.  When I work with my nand device, I use 'nand erase clean',
> which I thought would write the nand clean markers.  The jffs2 is
> expecting nand clean markers at every 4K (0x1000) bytes.
> 
> I'm wondering if my mkfs.jffs2 command is wrong, or if my use of nand
> erase is wrong, or if I need to specify something in either the kernel
> or the u-boot config is wrong.
> 

Extract from www.at91.com forum post:
"When using NAND make sure to pass the -n option to mkfs.jffs2 when creating the image.
Otherwise you will get errors about the cleanmarkers when you mount the filesystem"

> Any pointers are appreciated.
> 
> Thanks for everyone's hard work making u-boot a great tool.
> 
> Regards,
> 
> Matt G.
> 
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-- 
Best Regards,
Ulf Samuelsson
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[U-Boot-Users] NAND and JFFS2

[Matt Gessner]

Thanks for this, I've tried it, and got the same exact results.

> 
> Extract from www.at91.com forum post:
> "When using NAND make sure to pass the -n option to mkfs.jffs2 when
> creating the image.
> Otherwise you will get errors about the cleanmarkers when you mount
the
> filesystem"
> 
 
> 
> --
> Best Regards,
> Ulf Samuelsson

I'll keep looking, but if anyone else has any ideas, I'd love to hear
them.

Regards,

Matt Gessner

[U-Boot-Users] NAND and JFFS2

[Detlev Zundel]

Hi Matt,

> I'm using 1.2.0 on an AT91RM9200, along with linux 2.6.20-2 w/ patches
> from Maxim.
>
> I'm looking for info on how compatible the JFFS2 stuff is between u-boot
> and linux.

If that weren't the case what use would it be? ;)

> When I mount a partition (I have JFFS2 debugging turned on in the
> kernel), I get two kinds of error messages:
>
>
> OR
>
>
> I'm wondering if anyone can point me to what I'm doing wrong.

I am definitely not the guru on this, but I have a few suggestions.

First off, the JFFS2 (not NAND) cleanmarkers really were implemented
to circumvent strange problems with NOR flash not being erased
completely, so JFFS2 writes them _after_ erasing a sector.  In the
NAND implementation the designers use the out of band area of NAND to
store the cleanmarkers (don't ask me if they are technically needed
anymore).  So one potential problem is if you include cleanmarkers
without specifying "-n" to mkfs.jffs2 as this really produces output
for NOR flash - because the mkfs.jffs2 output does not include the OOB
area as such.

Some more theory.  You can always check the contents of your NAND
directly from U-Boot with "nand dump 0" for the first page for
example.

As you observed correctly, if you do a "nand erase clean", you will
write JFFS2 cleanmarkers in the OOB area of the NAND.  You can check
this with the "nand dump" command.  The cleanmarkers start with "19
85" (big endian).  Cf. jffs2_unknown_node in jffs2.h the next two
bytes are a node type and then we have a __u32 "totlen" field.

So now lets look at your output:

> 	"jffs2_check_nand_cleanmarker(): Cleanmarker node not detected
> in block at X"
> 	"OOB at X was ...."  (lots of FF)

Ok, probably you did a "nand erase" without clean and then this is to
be expected - but should only be a warning as JFFS2 will fix the
situation on the fly IIRC.

But this is interesting:

> 	"jffs2_check_nand_cleanmarker(): Cleanmarker node not detected
> in block at X"
> 	"OOB at X was ...."  (lots of data, not all FF)
> 	"CLEANMARKER node found at X has totlen 0xc != normal 0x0"

The "not all FF" probably is the cleanmarker from U-Boot which is
always 8 Bytes in U-Boot for NAND flash if I read current sources
correctly.

So the interesting part is to find out why the kernel sees 0xc bytes
here and expects 0.  If you find that out you should see mnore clearly
:)

Best wishes
  Detlev

-- 
Once the  implementation is  up and running,  it is still a trick to keep it
running.  In a normal,  closed implementation,  this is not a problem;  in a
system with metaobject protocols [..] there is the potential for spectacular
failure modes if certain situations are not properly anticipated.
                                       -- The Art of the Metaobject Protocol
--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
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