Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932402AbdIHPg1 (ORCPT ); Fri, 8 Sep 2017 11:36:27 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34590 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932217AbdIHPgW (ORCPT ); Fri, 8 Sep 2017 11:36:22 -0400 X-Google-Smtp-Source: AOwi7QCmB90PGajvrxgyno2VImub4kajbKyF2GWBVPatSuwFadgLbD+aw60VWHb+Sa34/c73B1k9+g== From: Romain Izard To: Nicolas Ferre , Boris Brezillon , Michael Turquette , Stephen Boyd , Ludovic Desroches , Jonathan Cameron , Wenyou Yang , Josh Wu , David Woodhouse , Brian Norris , Marek Vasut , Cyrille Pitchen , Thierry Reding , Richard Genoud , Greg Kroah-Hartman , Alan Stern Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, linux-mtd@lists.infradead.org, linux-pwm@vger.kernel.org, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Romain Izard Subject: [PATCH v1 04/10] mtd: nand: atmel: Avoid ECC errors when leaving backup mode Date: Fri, 8 Sep 2017 17:35:58 +0200 Message-Id: <20170908153604.28383-5-romain.izard.pro@gmail.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170908153604.28383-1-romain.izard.pro@gmail.com> References: <20170908153604.28383-1-romain.izard.pro@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2423 Lines: 62 During backup mode, the contents of all registers will be cleared as the SoC will be completely powered down. For a product that boots on NAND Flash memory, the bootloader will obviously use the related controller to read the Flash and correct any detected error in the memory, before handling back control to the kernel's resuming entry point. In normal devices, it is up to the driver's suspend/resume code to restore the registers in a valid state. But the PMECC is not a regular device in the driver model when used with the legacy device tree binding for the Atmel NAND controller, and suspend/resume code is not called. As in my case the bootloader leaves the PMECC controller in a programmed state, and the controller is only reset at boot or after a NAND access, the first NAND Flash access with the Atmel controller will report uncorrectable ECC errors. To avoid this, systematically reset the PMECC controller before using it. Signed-off-by: Romain Izard --- drivers/mtd/nand/atmel/pmecc.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/drivers/mtd/nand/atmel/pmecc.c b/drivers/mtd/nand/atmel/pmecc.c index 8c210a5776bc..8d1208f38025 100644 --- a/drivers/mtd/nand/atmel/pmecc.c +++ b/drivers/mtd/nand/atmel/pmecc.c @@ -777,6 +777,9 @@ int atmel_pmecc_enable(struct atmel_pmecc_user *user, int op) mutex_lock(&user->pmecc->lock); + writel(PMECC_CTRL_RST, pmecc->regs.base + ATMEL_PMECC_CTRL); + writel(PMECC_CTRL_DISABLE, pmecc->regs.base + ATMEL_PMECC_CTRL); + cfg = user->cache.cfg; if (op == NAND_ECC_WRITE) cfg |= PMECC_CFG_WRITE_OP; @@ -797,10 +800,6 @@ EXPORT_SYMBOL_GPL(atmel_pmecc_enable); void atmel_pmecc_disable(struct atmel_pmecc_user *user) { - struct atmel_pmecc *pmecc = user->pmecc; - - writel(PMECC_CTRL_RST, pmecc->regs.base + ATMEL_PMECC_CTRL); - writel(PMECC_CTRL_DISABLE, pmecc->regs.base + ATMEL_PMECC_CTRL); mutex_unlock(&user->pmecc->lock); } EXPORT_SYMBOL_GPL(atmel_pmecc_disable); @@ -856,10 +855,6 @@ static struct atmel_pmecc *atmel_pmecc_create(struct platform_device *pdev, /* Disable all interrupts before registering the PMECC handler. */ writel(0xffffffff, pmecc->regs.base + ATMEL_PMECC_IDR); - /* Reset the ECC engine */ - writel(PMECC_CTRL_RST, pmecc->regs.base + ATMEL_PMECC_CTRL); - writel(PMECC_CTRL_DISABLE, pmecc->regs.base + ATMEL_PMECC_CTRL); - return pmecc; } -- 2.11.0