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Subject: Re: FAT vs jFFS2 for NAND.
From: Thomas Gleixner <tglx@linutronix.de>
To: Claudio Lanconelli <lanconelli.claudio@eptar.com>
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Date: Wed, 21 Jun 2006 20:19:00 +0200
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Claudio,

On Wed, 2006-06-21 at 16:15 +0200, Claudio Lanconelli wrote:
> Are you sure about block 0 marked bad for protection? I read in
> smartmedia specification by Toshiba that SSFDC header called CIS/IDI is
> located on the first good block. Here the sentence:
> 
> "The CIS/IDI Field is placed in physical block 0.
> If physical block 0 is found to be a defective block, the area is placed 
> in the
> first normal block that is found after physical block 0.
> Irrespective of the page size, only one block is assigned."
> [...]
> "The indication of a defective block and logical block arrangement in 
> the data
> area will be set in the redundancy area.
> In the case of the 512+16 bytes/page models, the 6th byte (byte address 
> 517th)
> in all pages in the redundant section contains two or more “0” bits to 
> indicate
> a defective block."

ok

> My code follow these instructions on the SSFDC header location, is it 
> correct?
> Anyone who knows it for sure?

No, this was just from the top of my head.

> Another question about the ECC placement. I think the MTD default ECC 
> bytes placement
> in the redundant area is not suitable for SSFDC. I found the 
> CONFIG_MTD_NAND_ECC_SMC
> in mtd configuration, but it's not used anywhere in the code. How can 
> the ssfdc_ro layer tell
> to use smartmedia ECC bytes placement?

Well, if you use the device with SmartMedia FAT you probably want to
enable this switch and use the default configuration. I removed that
client supplied ECC scheme setting, as it turned out to be a complete
nightmare.

	tglx