From patchwork Fri Apr 29 20:21:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Dasu X-Patchwork-Id: 616962 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2001:1868:205::9]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3qxQBN2DTPz9t4b for ; Sat, 30 Apr 2016 06:23:24 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1awEvA-0007ZM-8d; Fri, 29 Apr 2016 20:21:52 +0000 Received: from mail-gw3-out.broadcom.com ([216.31.210.64]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1awEv7-0007SL-I7 for linux-mtd@lists.infradead.org; Fri, 29 Apr 2016 20:21:50 +0000 X-IronPort-AV: E=Sophos;i="5.24,553,1455004800"; d="scan'208";a="93872697" Received: from mail-irv-18.broadcom.com ([10.15.198.37]) by mail-gw3-out.broadcom.com with ESMTP; 29 Apr 2016 13:34:42 -0700 Received: from mail-irva-12.broadcom.com (mail-irva-12.broadcom.com [10.11.16.101]) by mail-irv-18.broadcom.com (Postfix) with ESMTP id 03E3682023; Fri, 29 Apr 2016 13:21:29 -0700 (PDT) Received: from kamal-linux-vm.and.broadcom.com (dhcp-mhtb-65-107.and.broadcom.com [10.28.65.107]) by mail-irva-12.broadcom.com (Postfix) with ESMTP id 177F6127622; Fri, 29 Apr 2016 13:21:27 -0700 (PDT) From: Kamal Dasu To: linux-mtd@lists.infradead.org, computersforpeace@gmail.com Subject: [PATCH 2/2] mtd: brcmnand: Detect sticky ucorr ecc error on dma reads Date: Fri, 29 Apr 2016 16:21:25 -0400 Message-Id: <1461961285-24159-2-git-send-email-kdasu.kdev@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1461961285-24159-1-git-send-email-kdasu.kdev@gmail.com> References: <1461961285-24159-1-git-send-email-kdasu.kdev@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160429_132149_668056_AB2220B9 X-CRM114-Status: GOOD ( 10.69 ) X-Spam-Score: -2.7 (--) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-2.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [216.31.210.64 listed in list.dnswl.org] 0.7 SPF_SOFTFAIL SPF: sender does not match SPF record (softfail) 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (kdasu.kdev[at]gmail.com) 0.0 DKIM_ADSP_CUSTOM_MED No valid author signature, adsp_override is CUSTOM_MED -0.0 RCVD_IN_MSPIKE_H4 RBL: Very Good reputation (+4) [216.31.210.64 listed in wl.mailspike.net] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.0 RCVD_IN_MSPIKE_WL Mailspike good senders 0.9 NML_ADSP_CUSTOM_MED ADSP custom_med hit, and not from a mailing list X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: f.fainelli@gmail.com, bcm-kernel-feedback-list@broadcom.com, Kamal Dasu MIME-Version: 1.0 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org This change provides a fix for controller bug where nand controller could have a possible sticky error after a PIO followed by a DMA read. The fix retries a read if we see a uncorr_ecc after read to detect such sticky errors. Signed-off-by: Kamal Dasu --- drivers/mtd/nand/brcmnand/brcmnand.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c index 29a9abd..13c7784 100644 --- a/drivers/mtd/nand/brcmnand/brcmnand.c +++ b/drivers/mtd/nand/brcmnand/brcmnand.c @@ -1555,9 +1555,11 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip, struct brcmnand_controller *ctrl = host->ctrl; u64 err_addr = 0; int err; + bool retry = true; dev_dbg(ctrl->dev, "read %llx -> %p\n", (unsigned long long)addr, buf); +try_dmaread: brcmnand_write_reg(ctrl, BRCMNAND_UNCORR_COUNT, 0); if (has_flash_dma(ctrl) && !oob && flash_dma_buf_ok(buf)) { @@ -1579,7 +1581,18 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip, if (mtd_is_eccerr(err)) { int ret; - + /* + * On controller version >=7.0 if we are doing a DMA read + * after a prior PIO read that reported uncorrectable error, + * the DMA engine captures this error following DMA read + * cleared only on subsequent DMA read, so just retry once + * to clear a possible false error reported for current DMA + * read + */ + if ((ctrl->nand_version >= 0x0700) && retry) { + retry = false; + goto try_dmaread; + } ret = brcmstb_nand_verify_erased_page(mtd, chip, buf, addr); if (ret < 0) { dev_dbg(ctrl->dev, "uncorrectable error at 0x%llx\n",