Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752228AbdLFPIK (ORCPT ); Wed, 6 Dec 2017 10:08:10 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:60574 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752119AbdLFPIJ (ORCPT ); Wed, 6 Dec 2017 10:08:09 -0500 Date: Wed, 6 Dec 2017 16:08:05 +0100 From: Boris Brezillon To: KOBAYASHI Yoshitake Cc: richard@nod.at, dwmw2@infradead.org, computersforpeace@gmail.com, marek.vasut@gmail.com, cyrille.pitchen@wedev4u.fr, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID Message-ID: <20171206160805.2435094b@bbrezillon> In-Reply-To: <1512569098-30038-2-git-send-email-yoshitake.kobayashi@toshiba.co.jp> References: <1512569098-30038-1-git-send-email-yoshitake.kobayashi@toshiba.co.jp> <1512569098-30038-2-git-send-email-yoshitake.kobayashi@toshiba.co.jp> X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2116 Lines: 60 On Wed, 6 Dec 2017 23:04:57 +0900 KOBAYASHI Yoshitake wrote: > This patch enables support to read the ECC strength and size from the > NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is > based on the information of the 6th ID byte of the Toshiba Memory SLC > NAND. > > Signed-off-by: KOBAYASHI Yoshitake > --- > drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c > index 57df857..c2c141b 100644 > --- a/drivers/mtd/nand/nand_toshiba.c > +++ b/drivers/mtd/nand/nand_toshiba.c > @@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip) > (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ && > !(chip->id.data[4] & 0x80) /* !BENAND */) > mtd->oobsize = 32 * mtd->writesize >> 9; > + > + /* > + * Extract ECC requirements from 6th id byte. > + * For Toshiba SLC, ecc requrements are as follows: > + * - 43nm: 1 bit ECC for each 512Byte is required. > + * - 32nm: 4 bit ECC for each 512Byte is required. > + * - 24nm: 8 bit ECC for each 512Byte is required. > + */ > + if (chip->id.len >= 6 && nand_is_slc(chip)) { > + chip->ecc_step_ds = 512; > + switch (chip->id.data[5] & 0x7) { > + case 0x4: > + chip->ecc_strength_ds = 1; > + break; > + case 0x5: > + chip->ecc_strength_ds = 4; > + break; > + case 0x6: > + chip->ecc_strength_ds = 8; > + break; > + default: > + WARN(1, "Could not get ECC info"); > + chip->ecc_step_ds = 0; > + break; > + } > + } else if (chip->id.len < 6 && nand_is_slc(chip)) { > + WARN(1, "Could not get ECC info, 6th nand id byte does not exist."); I'm pretty sure you have old NAND chips that do not have 6bytes ids (see the table here [1]), and printing a huge backtrace in this case is probably not what you want. If you're okay with dropping this else block, I'll do the change when applying, no need to send a new version. > + } > } > > static int toshiba_nand_init(struct nand_chip *chip)