From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from top.free-electrons.com ([176.31.233.9] helo=mail.free-electrons.com) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VYyQk-0006Lt-Fp for linux-mtd@lists.infradead.org; Wed, 23 Oct 2013 13:24:59 +0000 Date: Wed, 23 Oct 2013 10:24:58 -0300 From: Ezequiel Garcia To: "Gupta, Pekon" Subject: Re: [PATCH v10 04/10] mtd: nand: omap: fix device scan: NAND_CMD_READID, NAND_CMD_RESET, CMD_CMD_PARAM use only x8 bus Message-ID: <20131023132457.GD2458@localhost> References: <1382172254-12448-1-git-send-email-pekon@ti.com> <1382172254-12448-5-git-send-email-pekon@ti.com> <20131022201624.GL23337@ld-irv-0074.broadcom.com> <20980858CB6D3A4BAE95CA194937D5E73EA29DB8@DBDE04.ent.ti.com> <5267690C.9080005@gmail.com> <20131023125516.GA2458@localhost> <20980858CB6D3A4BAE95CA194937D5E73EA2A0CB@DBDE04.ent.ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20980858CB6D3A4BAE95CA194937D5E73EA2A0CB@DBDE04.ent.ti.com> Cc: "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "linux-omap@vger.kernel.org" , "arnd@arndb.de" , "Pawel.Moll@arm.com" , "ijc+devicetree@hellion.org.uk" , "tony@atomide.com" , "avinashphilipk@gmail.com" , "dedekind1@gmail.com" , "jp.francois@cynove.com" , "Balbi, Felipe" , "olof@lixom.net" , "robherring2@gmail.com" , "bcousson@baylibre.com" , "swarren@wwwdotorg.org" , "linux-mtd@lists.infradead.org" , "ivan.djelic@parrot.com" , Brian Norris , "dwmw2@infradead.org" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Gupta, On Wed, Oct 23, 2013 at 01:15:20PM +0000, Gupta, Pekon wrote: > Hi, > > > From: Ezequiel Garcia [mailto:ezequiel.garcia@free-electrons.com] > [...] > > FWIW, I have a Beaglebone with a 16-bit bus NAND attached to it. > > > > Coincidentally, yesterday I was doing some tests as I'm ramping up the > > NAND and I found that weird double nand_scan_ident() call. > > The whole thing looks buggy to me, so I'm happy to help, review, test > > and patches to take care of this. > > > Yes, thanks .. that would be of great help.. > And may be your experience of Atmel drivers would help me here.. > It's not Atmel, but Marvell :-) > *Correct, should not be double calls to nand_scan_ident()..* > But there is a constrain in nand_base.c, that it does not allow ONFI > page reading in x16 mode.. So how to overcome that.. > > I see the similar implementation in your ATMEL driver, it does not use > NAND_BUSWIDTH_AUTO so how do you perform ONFI read > for x16 devices ? > drivers/mtd/nand/atmel_nand.c @@atmel_nand_probe() > /* here you move to x16 mode based on your DT or platform data */ > if (host->board.bus_width_16) /* 16-bit bus width */ > nand_chip->options |= NAND_BUSWIDTH_16; > /* And then you call nand_scan_ident */ > /* first scan to find the device and get the page size */ > if (nand_scan_ident(mtd, 1, NULL)) { > res = -ENXIO; > goto err_scan_ident; > } > > Wouldn't this fail, _unless_ your device is listed in nand_flash_id[] ? > because it would not be able to read ONFI params.. > Refer below commit.. > commit 0ce82b7f7b7373b16ecf7b5725e21e2975204500 > Author: Matthieu CASTET > AuthorDate: 2013-01-16 > > Not my driver, but I'm taking a look at it now. Not sure if I'll get into something here. > > > > I'm using some TI SDK with some ancient v3.2.x (with no git history!), > > but from this discussion it seems the issue is still present in > > mainline. > > > Aah sorry, then you might have some problem here in rebasing the > patches. But still if you can, thanks much .. > I'm currently trying mainline (just for this issue not for my product). I just need some time to prepare the bootargs and write a DT node for the NAND cape. Again, not sure if I'll make some progress, but I'll give it a shot :-) -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com