From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Norris Subject: Re: [PATCH v2] mtd: atmel_nand: make PMECC lookup table and offset property optional Date: Fri, 19 Sep 2014 09:34:31 -0700 Message-ID: <20140919163431.GE1193@ld-irv-0074> References: <1408345720-5402-1-git-send-email-josh.wu@atmel.com> <20140918003258.GD1193@ld-irv-0074> <541A92E3.60906@atmel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <541A92E3.60906-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Josh Wu Cc: linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, pawel.moll-5wv7dgnIgG8@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org, galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On Thu, Sep 18, 2014 at 04:08:03PM +0800, Josh Wu wrote: > On 9/18/2014 8:32 AM, Brian Norris wrote: > >On Mon, Aug 18, 2014 at 03:08:40PM +0800, Josh Wu wrote: > >>+static int pmecc_build_galois_table(int mm, > >>+ int16_t *index_of, int16_t *alpha_to) > >>+{ ... > >>+} > >Is this algorithm documented? How did you come up with this? > > It is not documented in datasheet. It is based BCH algorithm. But do > you know if the soft BCH use a same table like this? I haven't delved into the algorithms here too much. Other BCH/ECC codes do similar steps, but either (1) there's usually a few comments about their origin or else (2) they're transparently handled by hardware ECC engines and software doesn't need to care about the details much. Brian -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html