From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.bootlin.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ffOMq-00049w-54 for linux-mtd@lists.infradead.org; Tue, 17 Jul 2018 11:42:10 +0000 Date: Tue, 17 Jul 2018 13:41:56 +0200 From: Boris Brezillon To: Chris Packham Cc: Richard Weinberger , Miquel Raynal , "linux-mtd@lists.infradead.org" , Marek Vasut , "Brian Norris" , David Woodhouse , Bean Huo Subject: Re: [2/3] mtd: rawnand: micron: Disable ECC earlier in the read path Message-ID: <20180717134156.3d8e016c@bbrezillon> In-Reply-To: References: <20180703122009.29914-3-boris.brezillon@bootlin.com> <20180716181057.65d78303@bbrezillon> <20180716225538.542cb096@bbrezillon> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 16 Jul 2018 22:42:54 +0000 Chris Packham wrote: > On 17/07/18 08:55, Boris Brezillon wrote: > > On Mon, 16 Jul 2018 18:10:57 +0200 > > Boris Brezillon wrote: > > > >> On Mon, 16 Jul 2018 09:00:59 +0000 > >> Chris Packham wrote: > >> > >>> Hi Boris, > >>> > >>> On 04/07/18 00:20, Boris Brezillon wrote: > >>>> We are about to support extracting the real number of bitflips for > >>>> 4-bits ECC when WRITE_RECOMMEND is returned. This requires re-reading > >>>> the page in raw mode to compare it to the corrected version, and this > >>>> logic will be placed in micron_nand_on_die_ecc_status_4(). > >>>> > >>>> Moving the micron_nand_on_die_ecc_setup() will allow us to disable > >>>> ECC only once. > >>>> > >>>> As a result, we have to rework the exit path and add an error path > >>>> where the ECC is disabled. > >>>> > >>>> Signed-off-by: Boris Brezillon > >>> > >>> As I said on the other thread this appears to cause a problem for me on > >>> the MT29F1G08ABAFAWP-ITE setup I have. I notice we're not able to find > >>> the BBT, not sure if that is symptom or cause. > > > > It's most likely the symptom, not the cause. > > > >>>> > >>>> diff --git a/drivers/mtd/nand/raw/nand_micron.c b/drivers/mtd/nand/raw/nand_micron.c > >>>> index 63ac98a36ed7..b9cbaf125a98 100644 > >>>> --- a/drivers/mtd/nand/raw/nand_micron.c > >>>> +++ b/drivers/mtd/nand/raw/nand_micron.c > >>>> @@ -197,30 +197,37 @@ micron_nand_read_page_on_die_ecc(struct mtd_info *mtd, struct nand_chip *chip, > >>>> > >>>> ret = nand_read_page_op(chip, page, 0, NULL, 0); > >>>> if (ret) > >>>> - goto out; > >>>> + goto err_disable_ecc; > >>>> > >>>> ret = nand_status_op(chip, &status); > >>>> if (ret) > >>>> - goto out; > >>>> + goto err_disable_ecc; > >>>> > >>>> ret = nand_exit_status_op(chip); > >>>> if (ret) > >>>> - goto out; > >>>> + goto err_disable_ecc; > >>>> > >>>> - if (chip->ecc.strength == 4) > >>>> - max_bitflips = micron_nand_on_die_ecc_status_4(chip, status); > >>>> - else > >>>> - max_bitflips = micron_nand_on_die_ecc_status_8(chip, status); > >>>> + micron_nand_on_die_ecc_setup(chip, false); > >> > >> Hm, can you try to move the micron_nand_on_die_ecc_setup(chip, false) > >> call just before nand_exit_status_op()? > >> > > > > Just pushed a branch fixing that [1]. Can you test it? If it works, > > I'll ask Miquel to drop the initial set of patches and instead pick the > > fixed ones so that we don't break bisectibility. > > > > [1]https://github.com/bbrezillon/linux-0day/commits/nand/next > > > > Still appears to have the same problem. > > I'm guessing that since you can't actually disable ecc on this chip > calling micron_nand_on_die_ecc_setup(chip, false); before reading the > oob data interferes with it somehow (if I call it after there is no > problem). > > We could add code to qualify the attempt to disable ecc early based on > it being optional/mandatory or just stick with it being disabled late. Okay. I gave up on disabling ECC earlier and instead implemented what you suggested. Can you test https://github.com/bbrezillon/linux-0day/commits/nand/next again and let me know if it works for you? Thanks, Boris