From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Schwarz Date: Fri, 26 Aug 2011 18:35:30 +0200 Subject: [U-Boot] [PATCH] NAND: Add nand read.raw and write.raw commands In-Reply-To: <201108261649.14880.marek.vasut@gmail.com> References: <1314309890-6613-1-git-send-email-marek.vasut@gmail.com> <4E5751DD.3090203@gmail.com> <201108261649.14880.marek.vasut@gmail.com> Message-ID: <4E57CB52.5000302@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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