From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [RFC PATCH 3/9] of: mtd: add NAND timings retrieval support Date: Tue, 21 Jan 2014 15:57:40 -0700 Message-ID: <20140121225740.GP18269@obsidianresearch.com> References: <1389190924-26226-1-git-send-email-b.brezillon@overkiz.com> <1389190924-26226-4-git-send-email-b.brezillon@overkiz.com> <20140108183418.GA12358@obsidianresearch.com> <52CDA032.3010804@overkiz.com> <20140108191339.GB12358@obsidianresearch.com> <52CE5F82.6070802@overkiz.com> <20140109173505.GB8899@obsidianresearch.com> <52D6A48D.4080302@overkiz.com> <52D6BF45.80407@overkiz.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <52D6BF45.80407-ZNYIgs0QAGpBDgjK7y7TUQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: boris brezillon Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Russell King , linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dev-3kdeTeqwOZ9EV1b7eY7vFQ@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Rob Landley , Grant Likely , Maxime Ripard , David Woodhouse , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Wed, Jan 15, 2014 at 06:03:01PM +0100, boris brezillon wrote: > >>Pick a mode value that fits all the parameters of the connected > >>non-ONFI flash. > >> > >>This would be instead of defining each parameter > >>individually.. Provide some helpers to convert from a onfi mode num= ber > >>to all the onfi defined timing parameters so that drivers can > >>configure the HW.. > > > >Are you suggesting we should provide a function that converts these > >modes into a nand_timings struct, or just use the timing modes and > >let the NAND controller drivers configure its IP accordingly ? Either seems reasonable to me, but passing the ONFI mode directly from the NAND core to the driver seems a little safer.. The NAND core can provide a helper function to xlate the mode number to the timing struct to help drivers that need broken out timing. > >I found the ONFI timing tables in this document: > > > >www.*onfi*.org/~/media/*ONFI*/specs/*onfi*_3_1_spec.pdf=E2=80=8E (ch= apter 4.16). > > > >I suppose my nand_timings struct should use the names described > >page 110-111 (at least if we decide to use nand_timings and not > >nand_timing_modes), right ? Yah, I think follow the standard. The standard has timing diagrams that show what all these parameters actually are. > After taking a closer look at this document, the only parameter > available in my nand_timings struct that is not defined in the > standard is tR_max (data transfer from cell to register). Maybe it can be derived from the other parameters? The ONFI values seemed pretty comprehensive to me. I think the mvebu driver was similar, not all of the ONFI values were used and some translation was needed. Jason -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html