From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752908AbeD3KAt (ORCPT ); Mon, 30 Apr 2018 06:00:49 -0400 Received: from mail.bootlin.com ([62.4.15.54]:45358 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751308AbeD3KAs (ORCPT ); Mon, 30 Apr 2018 06:00:48 -0400 Date: Mon, 30 Apr 2018 12:00:46 +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 1/2] Fix FSL NAND driver to read all ONFI parameter pages Message-ID: <20180430120046.3c87db2a@bbrezillon> In-Reply-To: <1524788396-32380-2-git-send-email-Jane.Wan@nokia.com> References: <1524788396-32380-1-git-send-email-Jane.Wan@nokia.com> <1524788396-32380-2-git-send-email-Jane.Wan@nokia.com> 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 Hi Jane, On Thu, 26 Apr 2018 17:19:55 -0700 Jane Wan wrote: > Signed-off-by: Jane Wan > --- > drivers/mtd/nand/fsl_ifc_nand.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c > index ca36b35..a3cf6ca 100644 > --- a/drivers/mtd/nand/fsl_ifc_nand.c > +++ b/drivers/mtd/nand/fsl_ifc_nand.c > @@ -413,6 +413,7 @@ static void fsl_ifc_cmdfunc(struct mtd_info *mtd, unsigned int command, > struct fsl_ifc_mtd *priv = chip->priv; > struct fsl_ifc_ctrl *ctrl = priv->ctrl; > struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs; > + int len; > > /* clear the read buffer */ > ifc_nand_ctrl->read_bytes = 0; > @@ -462,11 +463,12 @@ static void fsl_ifc_cmdfunc(struct mtd_info *mtd, unsigned int command, > ifc_out32(column, &ifc->ifc_nand.row3); > > /* > - * although currently it's 8 bytes for READID, we always read > - * the maximum 256 bytes(for PARAM) > + * For READID, read 8 bytes that are currently used. > + * For PARAM, read all 3 copies of 256-bytes pages. > */ > - ifc_out32(256, &ifc->ifc_nand.nand_fbcr); > - ifc_nand_ctrl->read_bytes = 256; > + len = (command == NAND_CMD_PARAM) ? (3 * 256) : 8; > + ifc_out32(len, &ifc->ifc_nand.nand_fbcr); > + ifc_nand_ctrl->read_bytes = len; This driver really calls for a clean rework to transition to ->exec_op(). Guessing the amount of data to be read from ->cmdfunc() is broken and your patch series just shows how broken this is. What next? What if some NANDs have 4 or more copies of the param page? I'm still undecided whether I want to apply this patch. I guess having some guarantees that someone will actually work on implementing ->exec_op() in a near future would help me take this decision. Regards, Boris