Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37FDCC433EF for ; Mon, 13 Dec 2021 10:04:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237929AbhLMKEL (ORCPT ); Mon, 13 Dec 2021 05:04:11 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:45162 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239853AbhLMJ64 (ORCPT ); Mon, 13 Dec 2021 04:58:56 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 22BA2B80E83; Mon, 13 Dec 2021 09:58:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38045C34601; Mon, 13 Dec 2021 09:58:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1639389529; bh=CaGJg9L+b7+ixx5BF0mYsdNS66KsGLOlP7xuy9QgWP0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hicCgY1erzweNzfYfH4MPolSxN8pQLZ4KdGVKtdNuW6yBO70nY4ikZsqJ/TkVAuHq ukVYk/E0jaH6RvHlByI/y4eIB6Fsfbey+eD81lhm2mh04BzXazBSH4waBT5rQ9M8qX OGoTtCa1Hpm77l+Hb3IcHhBqWUc4YptGYY/usjAw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Herve Codina , Miquel Raynal Subject: [PATCH 5.15 121/171] mtd: rawnand: fsmc: Fix timing computation Date: Mon, 13 Dec 2021 10:30:36 +0100 Message-Id: <20211213092949.124725791@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211213092945.091487407@linuxfoundation.org> References: <20211213092945.091487407@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Herve Codina commit 9472335eaa1452b51dc8e8edaa1a342997cb80c7 upstream. Under certain circumstances, the timing settings calculated by the FSMC NAND controller driver were inaccurate. These settings led to incorrect data reads or fallback to timing mode 0 depending on the NAND chip used. The timing computation did not take into account the following constraint given in SPEAr3xx reference manual: twait >= tCEA - (tset * TCLK) + TOUTDEL + TINDEL Enhance the timings calculation by taking into account this additional constraint. This change has no impact on slow timing modes such as mode 0. Indeed, on mode 0, computed values are the same with and without the patch. NANDs which previously stayed in mode 0 because of fallback to mode 0 can now work at higher speeds and NANDs which were not working at all because of the corrupted data work at high speeds without troubles. Overall improvement on a Micron/MT29F1G08 (flash_speed tool): mode0 mode3 eraseblock write speed 3220 KiB/s 4511 KiB/s eraseblock read speed 4491 KiB/s 7529 KiB/s Fixes: d9fb079571833 ("mtd: nand: fsmc: add support for SDR timings") Signed-off-by: Herve Codina Signed-off-by: Miquel Raynal Link: https://lore.kernel.org/linux-mtd/20211119150316.43080-5-herve.codina@bootlin.com Signed-off-by: Greg Kroah-Hartman --- drivers/mtd/nand/raw/fsmc_nand.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) --- a/drivers/mtd/nand/raw/fsmc_nand.c +++ b/drivers/mtd/nand/raw/fsmc_nand.c @@ -94,6 +94,14 @@ #define FSMC_BUSY_WAIT_TIMEOUT (1 * HZ) +/* + * According to SPEAr300 Reference Manual (RM0082) + * TOUDEL = 7ns (Output delay from the flip-flops to the board) + * TINDEL = 5ns (Input delay from the board to the flipflop) + */ +#define TOUTDEL 7000 +#define TINDEL 5000 + struct fsmc_nand_timings { u8 tclr; u8 tar; @@ -278,7 +286,7 @@ static int fsmc_calc_timings(struct fsmc { unsigned long hclk = clk_get_rate(host->clk); unsigned long hclkn = NSEC_PER_SEC / hclk; - u32 thiz, thold, twait, tset; + u32 thiz, thold, twait, tset, twait_min; if (sdrt->tRC_min < 30000) return -EOPNOTSUPP; @@ -310,13 +318,6 @@ static int fsmc_calc_timings(struct fsmc else if (tims->thold > FSMC_THOLD_MASK) tims->thold = FSMC_THOLD_MASK; - twait = max(sdrt->tRP_min, sdrt->tWP_min); - tims->twait = DIV_ROUND_UP(twait / 1000, hclkn) - 1; - if (tims->twait == 0) - tims->twait = 1; - else if (tims->twait > FSMC_TWAIT_MASK) - tims->twait = FSMC_TWAIT_MASK; - tset = max(sdrt->tCS_min - sdrt->tWP_min, sdrt->tCEA_max - sdrt->tREA_max); tims->tset = DIV_ROUND_UP(tset / 1000, hclkn) - 1; @@ -325,6 +326,21 @@ static int fsmc_calc_timings(struct fsmc else if (tims->tset > FSMC_TSET_MASK) tims->tset = FSMC_TSET_MASK; + /* + * According to SPEAr300 Reference Manual (RM0082) which gives more + * information related to FSMSC timings than the SPEAr600 one (RM0305), + * twait >= tCEA - (tset * TCLK) + TOUTDEL + TINDEL + */ + twait_min = sdrt->tCEA_max - ((tims->tset + 1) * hclkn * 1000) + + TOUTDEL + TINDEL; + twait = max3(sdrt->tRP_min, sdrt->tWP_min, twait_min); + + tims->twait = DIV_ROUND_UP(twait / 1000, hclkn) - 1; + if (tims->twait == 0) + tims->twait = 1; + else if (tims->twait > FSMC_TWAIT_MASK) + tims->twait = FSMC_TWAIT_MASK; + return 0; }