From patchwork Thu Dec 20 14:10:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Brezillon X-Patchwork-Id: 1016781 X-Patchwork-Delegate: miquel.raynal@bootlin.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.infradead.org (client-ip=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Mktp4H87"; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 43LDFd28YDz9s8r for ; Fri, 21 Dec 2018 01:11:17 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=NKvohAGicSZWM7hRuxJEYLeASv0NWx7JGFQf6k3js3E=; b=Mkt p4H87SaXKZa22lrcNN8gA/8ABW7nlFTbvbXzqHGFNRpesv5mTYzWghyXreKj6DzVe9/k6BDIYx/8w ytGTiMKcO++7k2LhHmHK2PLKAxc7V/O+siLOmwl5YYS03DT8l76ZPLh2CtHXx9QsyrmWruvqTeUJk 5NZ4O1EonvMbZqpZIDIdk5Dwxun9PBvi5wLv+NbTOTJmjtkd5tPdPQMxdYQL3VYUkAPx+hO8QiXe5 t3M2UswB9TIrZ09gxrpbJKXDNO5ImDw//unX1kozW5OcgmmpU9BmRCwf40o0KKktOZpf+FRawEGl0 aCfsaFEUL+alqcQt9m0sjetnY+MCS/w==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gZz2f-0000DQ-Fd; Thu, 20 Dec 2018 14:11:13 +0000 Received: from mail.bootlin.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gZz2c-0000Cj-72 for linux-mtd@lists.infradead.org; Thu, 20 Dec 2018 14:11:11 +0000 Received: by mail.bootlin.com (Postfix, from userid 110) id 914B32077B; Thu, 20 Dec 2018 15:10:58 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on mail.bootlin.com X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,SHORTCIRCUIT shortcircuit=ham autolearn=disabled version=3.4.2 Received: from localhost.localdomain (aaubervilliers-681-1-38-38.w90-88.abo.wanadoo.fr [90.88.157.38]) by mail.bootlin.com (Postfix) with ESMTPSA id 4F5BE20717; Thu, 20 Dec 2018 15:10:48 +0100 (CET) From: Boris Brezillon To: Boris Brezillon , Richard Weinberger , Miquel Raynal , linux-mtd@lists.infradead.org Subject: [PATCH] mtd: rawnand: sunxi: Handle the tREA > tRC / 2 case Date: Thu, 20 Dec 2018 15:10:47 +0100 Message-Id: <20181220141047.31733-1-boris.brezillon@bootlin.com> X-Mailer: git-send-email 2.17.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181220_061110_390852_B78E877C X-CRM114-Status: GOOD ( 14.12 ) X-Spam-Score: -0.0 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [62.4.15.54 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marek Vasut , Brian Norris , David Woodhouse MIME-Version: 1.0 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org In non-EDO, tREA should be less than tRP to guarantee that the controller does not sample the IO lines too early. Unfortunately, the sunxi NAND controller does not allow us to have different values for tRP and tREH (tRP = tREH = tRW / 2). We have 2 options to overcome this limitation: 1/ Extend tRC to fulfil the tREA <= tRC / 2 constraint 2/ Use EDO mode (only works if timings->tRLOH > 0) Signed-off-by: Boris Brezillon --- drivers/mtd/nand/raw/sunxi_nand.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/nand/raw/sunxi_nand.c b/drivers/mtd/nand/raw/sunxi_nand.c index 4fd1f8da6906..4282bc477761 100644 --- a/drivers/mtd/nand/raw/sunxi_nand.c +++ b/drivers/mtd/nand/raw/sunxi_nand.c @@ -1442,6 +1442,20 @@ static int sunxi_nfc_setup_data_interface(struct nand_chip *nand, int csline, if (timings->tRHW_min > (min_clk_period * 20)) min_clk_period = DIV_ROUND_UP(timings->tRHW_min, 20); + /* + * In non-EDO, tREA should be less than tRP to guarantee that the + * controller does not sample the IO lines too early. Unfortunately, + * the sunxi NAND controller does not allow us to have different + * values for tRP and tREH (tRP = tREH = tRW / 2). + * + * We have 2 options to overcome this limitation: + * + * 1/ Extend tRC to fulfil the tREA <= tRC / 2 constraint + * 2/ Use EDO mode (only works if timings->tRLOH > 0) + */ + if (timings->tREA_max > min_clk_period && !timings->tRLOH_min) + min_clk_period = timings->tREA_max; + tWB = sunxi_nand_lookup_timing(tWB_lut, timings->tWB_max, min_clk_period); if (tWB < 0) { @@ -1497,14 +1511,16 @@ static int sunxi_nfc_setup_data_interface(struct nand_chip *nand, int csline, return -EINVAL; } + sunxi_nand->timing_ctl = 0; + /* * ONFI specification 3.1, paragraph 4.15.2 dictates that EDO data * output cycle timings shall be used if the host drives tRC less than - * 30 ns. + * 30 ns. We should also use EDO mode if tREA is bigger than tRP. */ min_clk_period = NSEC_PER_SEC / real_clk_rate; - sunxi_nand->timing_ctl = ((min_clk_period * 2) < 30) ? - NFC_TIMING_CTL_EDO : 0; + if (min_clk_period * 2 < 30 || min_clk_period * 1000 < timings->tREA_max) + sunxi_nand->timing_ctl = NFC_TIMING_CTL_EDO; return 0; }