[U-Boot] [PATCH] NAND: Add nand read.raw and write.raw commands

[Simon Schwarz <simonschwarzcor@googlemail.com>]

On 08/26/2011 04:49 PM, Marek Vasut wrote:
> On Friday, August 26, 2011 09:57:17 AM Simon Schwarz wrote:
>> Dear Marek,
>>
>> On 08/26/2011 12:04 AM, Marek Vasut wrote:
>>> These commands should work around various "hardware" ECC and BCH methods.
>>> This is important for example in case where the user needs to write
>>> precisely what's in a buffer to a NAND page, with no interference of
>>> hardware ECC engine or such.
>>
>> I think I don't get it :)
>>
>> Where is the problem with writing this stuff to NAND now? If the ECC
>> interferes there was a problem with the NAND Flash therefore the data is
>> corrupted.
>
> It's not an issue with data corruption. For example in my case, if
> nand_write_skip_bad() is called, HW ECC writes the ECC information in various
> places in the page. But if done this way, exactly what's in the buffer is written
> to the page.

But isn't then the HW ECC misconfigured? AFAIK ECC information should be 
written only to the OOB never into the normal page.

I'am really not sure if I understand the patch - it seems to me that you 
are writing/reading the oob while this collides with the description 
that you want to write data. Could you explain further what exactly the 
patch is supposed to do?

Regards
Simon