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 1ffXZd-0005iQ-U7 for linux-mtd@lists.infradead.org; Tue, 17 Jul 2018 21:32:00 +0000 Date: Tue, 17 Jul 2018 23:31:43 +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: <20180717233143.030b9935@bbrezillon> In-Reply-To: <16b088c3887b4f1b84bd1002b0de75cb@svr-chch-ex1.atlnz.lc> References: <20180703122009.29914-3-boris.brezillon@bootlin.com> <20180716181057.65d78303@bbrezillon> <20180716225538.542cb096@bbrezillon> <20180717134156.3d8e016c@bbrezillon> <16b088c3887b4f1b84bd1002b0de75cb@svr-chch-ex1.atlnz.lc> 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 Tue, 17 Jul 2018 21:27:26 +0000 Chris Packham wrote: > Hi Boris, > > On 17/07/18 23:42, Boris Brezillon wrote: > > 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? > > Yes that works for me. Feel free to add > > Tested-by: Chris Packham > > to > > 88240e244026 mtd: rawnand: micron: Make ECC activation stateful > 6ae7f205cec0 mtd: rawnand: micron: Avoid enabling/disabling ECC when it > can't be disabled Okay, cool. Miquel, can you drop: 683ca8a70738 mtd: rawnand: micron: Get the actual number of bitflips d73e5d29aa29 mtd: rawnand: micron: Disable ECC earlier in the read path db2d37331813 mtd: rawnand: micron: Stop passing mtd to ecc_status() funcs 51f3b3970a8c mtd: rawnand: micron: detect forced on-die ECC 386fc2609d15 mtd: rawnand: micron: support 8/512 on-die ECC I'll send a new patch series soon. Thanks, Boris