From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751269AbeEBKbu (ORCPT ); Wed, 2 May 2018 06:31:50 -0400 Received: from mail.bootlin.com ([62.4.15.54]:45827 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750878AbeEBKbt (ORCPT ); Wed, 2 May 2018 06:31:49 -0400 Date: Wed, 2 May 2018 12:31:37 +0200 From: Boris Brezillon To: Jane Wan Cc: dwmw2@infradead.org, computersforpeace@gmail.com, ties.bos@nokia.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] Use bit-wise majority to recover the contents of ONFI parameter Message-ID: <20180502123137.60d151fd@bbrezillon> In-Reply-To: <20180502122545.6bd28c3b@bbrezillon> References: <1524788396-32380-1-git-send-email-Jane.Wan@nokia.com> <1524788396-32380-3-git-send-email-Jane.Wan@nokia.com> <20180502122545.6bd28c3b@bbrezillon> X-Mailer: Claws Mail 3.15.0-dirty (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 On Wed, 2 May 2018 12:25:45 +0200 Boris Brezillon wrote: > Hi Jane, > > On Thu, 26 Apr 2018 17:19:56 -0700 > Jane Wan wrote: > > > Signed-off-by: Jane Wan > > --- > > drivers/mtd/nand/nand_base.c | 35 +++++++++++++++++++++++++++++++---- > > 1 file changed, 31 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > > index c2e1232..161b523 100644 > > --- a/drivers/mtd/nand/nand_base.c > > +++ b/drivers/mtd/nand/nand_base.c > > @@ -3153,8 +3153,10 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip, > > int *busw) > > { > > struct nand_onfi_params *p = &chip->onfi_params; > > - int i, j; > > - int val; > > + int i, j, k, len, val; > > + uint8_t copy[3][256], v8; > > + > > + len = (sizeof(*p) > 256) ? 256 : sizeof(*p); > > > > /* Try ONFI for unknown chip or LP */ > > chip->cmdfunc(mtd, NAND_CMD_READID, 0x20, -1); > > @@ -3170,11 +3172,36 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip, > > le16_to_cpu(p->crc)) { > > break; > > } > > + pr_err("CRC of parameter page %d is not valid\n", i); > > + for (j = 0; j < len; j++) > > + copy[i][j] = ((uint8_t *)p)[j]; > > } > > > > if (i == 3) { > > - pr_err("Could not find valid ONFI parameter page; aborting\n"); > > - return 0; > > + pr_err("Could not find valid ONFI parameter page\n"); > > + pr_info("Recover ONFI parameters with bit-wise majority\n"); > > + for (j = 0; j < len; j++) { > > + if (copy[0][j] == copy[1][j] || > > + copy[0][j] == copy[2][j]) { > > + ((uint8_t *)p)[j] = copy[0][j]; > > + } else if (copy[1][j] == copy[2][j]) { > > + ((uint8_t *)p)[j] = copy[1][j]; > > + } else { > > + ((uint8_t *)p)[j] = 0; > > + for (k = 0; k < 8; k++) { > > + v8 = (copy[0][j] >> k) & 0x1; > > + v8 += (copy[1][j] >> k) & 0x1; > > + v8 += (copy[2][j] >> k) & 0x1; > > + if (v8 > 1) > > + ((uint8_t *)p)[j] |= (1 << k); > > + } > > + } > > + } > > I'd like this bit-wise majority algorithm to be generic and moved to > nand_base.c, because we might want to do the same in the core and make > it work for any number of repetitions of the PARAM page. Never mind, I thought you were implementing that in the FSL IFC driver, but you're actually modifying the core.