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 1fDmqH-0005y9-22 for linux-mtd@lists.infradead.org; Wed, 02 May 2018 08:10:27 +0000 Date: Wed, 2 May 2018 10:10:11 +0200 From: Miquel Raynal To: "Wan, Jane (Nokia - US/Sunnyvale)" Cc: Boris Brezillon , "dwmw2@infradead.org" , "computersforpeace@gmail.com" , "Bos, Ties (Nokia - US/Sunnyvale)" , "linux-mtd@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "richard@nod.at" , "marek.vasut@gmail.com" , "yamada.masahiro@socionext.com" , "prabhakar.kushwaha@nxp.com" , "shawnguo@kernel.org" , "jagdish.gediya@nxp.com" , "shreeya.patel23498@gmail.com" Subject: Re: [PATCH 1/2] Fix FSL NAND driver to read all ONFI parameter pages Message-ID: <20180502101011.797e4ec4@xps13> In-Reply-To: References: <1524788396-32380-1-git-send-email-Jane.Wan@nokia.com> <1524788396-32380-2-git-send-email-Jane.Wan@nokia.com> <20180428134218.3ae857eb@xps13> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Jane, On Tue, 1 May 2018 05:01:23 +0000, "Wan, Jane (Nokia - US/Sunnyvale)" wrote: > Hi Miqu=C3=A8l and Boris, >=20 > Thank you for your response and feedback. I've modified the fix based on= your comments. =20 > Please see the updated patch file at the end of this message (also in att= achment). > My answers to your comments/questions are inline in the previous message. Usually we answer inline in each e-mail, then we post a new version with a version counter incremented (use the '-v2- of 'git format-patch' to add the '[PATCH v2 x/y]' prefix automatically). Reposting is important as maintainers use 'patchwork' to follow the evolution of each patch. So in your case, nothing shows that you posted a v2. >=20 > Here is the answer to Boris question in another email thread: >=20 > > What if some NANDs have 4 or more copies of the param page? =20 > [Jane] The ONFI spec defines that the parameter page and its two redunda= nt copies are mandatory. =20 > The additional redundant pages are optional. Currently, the FSL NAND dri= ver only reads the first=20 > parameter page. This patch is to fix the driver to meet the mandatory re= quirement in the spec.=20 > We got a batch of particularly bad NAND chips recently and we needed thes= e changes to make them=20 > work reliably over temperature. The patch was verified using these bad c= hips. I think Boris' remark was much more general than just this use case. The whole logic of tailoring ->cmdfunc() in each driver by guessing the data length, while there is absolutely no indication of it in this hook is broken. The core is moving to a new interface called ->exec_op(), and we would welcome a migration of this driver to this hook, that would be much much more easy to maintain for everyone. Thanks, Miqu=C3=A8l >=20 > Best regards, > Jane >=20 > Updated patch: > From 701de4146aa6355c951e97a77476e12d2da56d42 Mon Sep 17 00:00:00 2001 > From: Jane Wan > Date: Mon, 30 Apr 2018 13:30:46 -0700 > Subject: [PATCH 1/2] mtd: rawnand: fsl_ifc: fix FSL NAND driver to read a= ll > ONFI parameter pages >=20 > Per ONFI specification (Rev. 4.0), if the CRC of the first parameter page > read is not valid, the host should read redundant parameter page copies. > Fix FSL NAND driver to read the two redundant copies which are mandatory > in the specification. >=20 > Signed-off-by: Jane Wan > --- > drivers/mtd/nand/raw/fsl_ifc_nand.c | 17 ++++++++++------- > 1 file changed, 10 insertions(+), 7 deletions(-) >=20 > diff --git a/drivers/mtd/nand/raw/fsl_ifc_nand.c b/drivers/mtd/nand/raw/f= sl_ifc_nand.c > index 61aae02..98aac1f 100644 > --- a/drivers/mtd/nand/raw/fsl_ifc_nand.c > +++ b/drivers/mtd/nand/raw/fsl_ifc_nand.c > @@ -342,9 +342,16 @@ static void fsl_ifc_cmdfunc(struct mtd_info *mtd, un= signed int command, > =20 > case NAND_CMD_READID: > case NAND_CMD_PARAM: { > + /* > + * For READID, read 8 bytes that are currently used. > + * For PARAM, read all 3 copies of 256-bytes pages. > + */ > + int len =3D 8; > int timing =3D IFC_FIR_OP_RB; > - if (command =3D=3D NAND_CMD_PARAM) > + if (command =3D=3D NAND_CMD_PARAM) { > timing =3D IFC_FIR_OP_RBCD; > + len =3D 256 * 3; > + } > =20 > ifc_out32((IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) | > (IFC_FIR_OP_UA << IFC_NAND_FIR0_OP1_SHIFT) | > @@ -354,12 +361,8 @@ static void fsl_ifc_cmdfunc(struct mtd_info *mtd, un= signed int command, > &ifc->ifc_nand.nand_fcr0); > ifc_out32(column, &ifc->ifc_nand.row3); > =20 > - /* > - * although currently it's 8 bytes for READID, we always read > - * the maximum 256 bytes(for PARAM) > - */ > - ifc_out32(256, &ifc->ifc_nand.nand_fbcr); > - ifc_nand_ctrl->read_bytes =3D 256; > + ifc_out32(len, &ifc->ifc_nand.nand_fbcr); > + ifc_nand_ctrl->read_bytes =3D len; > =20 > set_addr(mtd, 0, 0, 0); > fsl_ifc_run_command(mtd); --=20 Miquel Raynal, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com