From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <552FBC0E.20004@gmail.com> Date: Thu, 16 Apr 2015 15:41:34 +0200 From: Sebastian Hesselbarth To: Ezequiel Garcia , Antoine Tenart , dwmw2@infradead.org, computersforpeace@gmail.com Subject: Re: [PATCH v4 04/10] mtd: pxa3xx_nand: rework flash detection and timing setup References: <1429118648-19416-1-git-send-email-antoine.tenart@free-electrons.com> <1429118648-19416-5-git-send-email-antoine.tenart@free-electrons.com> <552EB7F0.2090106@gmail.com> <552FB4DF.1030403@free-electrons.com> In-Reply-To: <552FB4DF.1030403@free-electrons.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: zmxu@marvell.com, boris.brezillon@free-electrons.com, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, jszhang@marvell.com, Robert Jarzmik , linux-arm-kernel@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 04/16/2015 03:10 PM, Ezequiel Garcia wrote: > On 04/15/2015 04:11 PM, Sebastian Hesselbarth wrote: >> On 15.04.2015 19:24, Antoine Tenart wrote: >>> Rework the pxa3xx_nand driver to allow using functions exported by the >>> nand framework to detect the flash and to configure the timings. >>> >>> Because this driver supports some non-ONFI devices, we also keep the >>> custom timing setup of this driver so these devices won't break. >>> >>> Signed-off-by: Antoine Tenart >>> --- >> [...] >> How about we get rid of the driver specific timings completely >> and pick up the best onfi timing match instead? The nand_ids table >> allows for a default_onfi_timing parameter even if onfi itself is >> not supported. >> >> For generic flash, i.e. no specific entry in the nand_ids table, >> we either choose onfi mode 0 (most conservative) or an even slower >> one. >> > > I think Robert mentioned [1] that using "ONFI default timings" on > non-ONFI devices didn't work for him. > > [1] https://lkml.org/lkml/2015/3/8/124 Ok, I see. But there is still the option to pass board specific timings with driver's platform_data. We could use (a) pdata timings if passed (b) onfi timings if available (c) equivalent onfi timings if set (d) conservative equivalent onfi timings otherwise All we need is a function to convert sdr_timings to sane driver timings. And we really need to split this patch into tiny pieces otherwise it is not reviewable - or at least I need a full overview about the driver first. Also, as soon as Robert moves pxa3xx boards fully to DT, we'll loose the pdata timings option above. *sigh* Thoughts? Sebastian