Some problem in real application

Some problem in real application

[Jacky Lam]

Dear all,

I am new to UBI and want to apply it in a real production application.
However, I have a technical problem and hope anyone can give me some advice.

I use NFTL before. While in production, we use some self-made IO
programmer to program the NAND flash. We first write the data and ecc
(in spare area), and then read then back. After verify it with ECC, we
can tell whether the data is written correctly or not.

However, in UBI, it doesn't use spare area and embedded the ECC
information in main area. Will it be difficult to extract the ECC
information from the read back data in order to do verification? I am
worry about our self-made IO programmer is too slow for handling UBI.
(Or any other clever way to do that?)

If my question is not clear or even wrong, please point me out. Thanks
very much for help.

BR,
Jacky


Disclaimer: This email and attachments are confidential. If you are not the intended recipient, you must not pursue, use, disseminate, distribute or copy this message, whether in whole or in part. If you have received this message in error, please notify us immediately by email or telephone us at (852) 2832 8228 and delete this message from your system. We do not represent that this email may not be interfered with, may not contain computer viruses or other defects and may not be successfully replicated on other system. 

Re: Some problem in real application

[Artem Bityutskiy]

Hi,

Theoretically, I cannot respond you because of the silly disclamer
you added to the end of your e-mail. However,

On Mon, 2009-01-12 at 16:57 +0800, Jacky Lam wrote:
> I use NFTL before. While in production, we use some self-made IO
> programmer to program the NAND flash. We first write the data and ecc
> (in spare area), and then read then back. After verify it with ECC, we
> can tell whether the data is written correctly or not.

Fine. Just do the same with UBI images.

> However, in UBI, it doesn't use spare area and embedded the ECC
> information in main area.

UBI itself does not use OOB. But the NAND driver or NAND controller
may use it to store ECC codes.

>  Will it be difficult to extract the ECC
> information from the read back data in order to do verification?

The ECC verification is done in the driver level. UBI is above the
driver - it asks the driver to read and write NAND pages. And the
driver verifies/calculates ECC codes.

I'm going to update UBI documentation soon and write a little bit more
about what the UBI-aware flasher should do. I'll send you a link later.

-- 
Best regards,
Artem Bityutskiy (Битюцкий Артём)

Re: Some problem in real application

[Artem Bityutskiy]

On Tue, 2009-01-13 at 10:53 +0200, Artem Bityutskiy wrote:
> I'm going to update UBI documentation soon and write a little bit more
> about what the UBI-aware flasher should do. I'll send you a link later.

Done. Here are details about how to flash UBI images properly:

http://www.linux-mtd.infradead.org/doc/ubi.html#L_format_det

-- 
Best regards,
Artem Bityutskiy (Битюцкий Артём)

Re: Some problem in real application

[Artem Bityutskiy]

On Wed, 2009-01-14 at 09:22 +0800, Jacky Lam wrote:  
>     That means  I can still use nanddump utility to extract the nand
> raw image and put it back to a blank new flash?

I think so. But read the link I sent you.

-- 
Best regards,
Artem Bityutskiy (Битюцкий Артём)