From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?Andreas_Bie=DFmann?= Date: Wed, 21 Nov 2012 21:51:53 +0100 Subject: [U-Boot] [PATCH v2 6/8] omap_gpmc: BCH8 support (ELM based) In-Reply-To: <20121121170442.GB6794@oliver-linux> References: <1352243195-64326-1-git-send-email-ilya.yanok@cogentembedded.com> <1352243195-64326-7-git-send-email-ilya.yanok@cogentembedded.com> <50A4ED43.5060505@gmail.com> <20121121170442.GB6794@oliver-linux> Message-ID: <50AD3EE9.7080204@googlemail.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 21.11.12 18:04, Tom Rini wrote: > On Thu, Nov 15, 2012 at 02:25:23PM +0100, Andreas Bie?mann wrote: >> Dear Ilya Yanok, >> >> On 07.11.2012 00:06, Ilya Yanok wrote: >>> From: Mansoor Ahamed >>> >>> This patch adds support for BCH8 error correction code to omap_gpmc >>> driver. We use GPMC to generate codes/syndromes but we need ELM to find >>> error locations from given syndrome. >>> >> >> first of all, I wonder why this is so different than the kernel >> implementation for BCH. I mean the API (and content) of this and commit >> 8d602cf50d3bba864bc1438f486b626df69c87b3 mainline linux seems to differ. >> The main question coming to mind is: Is the resulting OOB layout >> compatible then? > > I think this has been mostly addressed now, but for clarity: > - We do NOT want to have > 1 layout used per NAND chip unless we must > (historically we did because we had ROM that couldn't use >1bit ECC). > - We DO want to utilize the HW as this is the only easy way to get a > match with the BCH constants the ROM uses. > - There are corresponding kernel patches already posted and working > their way along. I'm fine with all these three points. My question came up when I looked into this deeply the very first time cause BCH4/8 support was missing for OMAP35xx/AM37xx devices. I do have now working support for these (hw assisted BCH but sw correction) like the kernel does. It needs some final polishing however I will send it these days as RFC, would be great to get some feedback. Best regards Andreas Bie?mann