Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752514AbbBROIv (ORCPT ); Wed, 18 Feb 2015 09:08:51 -0500 Received: from down.free-electrons.com ([37.187.137.238]:39523 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751527AbbBROIr (ORCPT ); Wed, 18 Feb 2015 09:08:47 -0500 Message-ID: <54E49C5E.3090300@free-electrons.com> Date: Wed, 18 Feb 2015 11:06:22 -0300 From: Ezequiel Garcia User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Maxime Ripard CC: Gregory Clement , Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , Brian Norris , linux-mtd@lists.infradead.org, Boris Brezillon , Thomas Petazzoni , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Tawfik Bayouk , Nadav Haklai , Lior Amsalem , Sudhakar Gundubogula , Seif Mazareeb , stable@vger.kernel.org Subject: Re: [PATCH v4 1/2] mtd: nand: pxa3xx: Fix PIO FIFO draining References: <1424255528-1717-1-git-send-email-maxime.ripard@free-electrons.com> <1424255528-1717-2-git-send-email-maxime.ripard@free-electrons.com> <54E49632.1000001@free-electrons.com> <20150218140143.GQ25269@lukather> In-Reply-To: <20150218140143.GQ25269@lukather> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3846 Lines: 87 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 02/18/2015 11:01 AM, Maxime Ripard wrote: > On Wed, Feb 18, 2015 at 10:40:02AM -0300, Ezequiel Garcia wrote: >> On 02/18/2015 07:32 AM, Maxime Ripard wrote: >>> The NDDB register holds the data that are needed by the read >>> and write commands. >>> >>> However, during a read PIO access, the datasheet specifies that >>> after each 32 bytes read in that register, when BCH is enabled, >>> we have to make sure that the RDDREQ bit is set in the NDSR >>> register. >>> >>> This fixes an issue that was seen on the Armada 385, and >>> presumably other mvebu SoCs, when a read on a newly erased page >>> would end up in the driver reporting a timeout from the NAND. >>> >>> Cc: # v3.14 Signed-off-by: Maxime >>> Ripard --- >>> drivers/mtd/nand/pxa3xx_nand.c | 48 >>> ++++++++++++++++++++++++++++++++++++------ 1 file changed, 42 >>> insertions(+), 6 deletions(-) >>> >>> diff --git a/drivers/mtd/nand/pxa3xx_nand.c >>> b/drivers/mtd/nand/pxa3xx_nand.c index >>> 96b0b1d27df1..bc677362bc73 100644 --- >>> a/drivers/mtd/nand/pxa3xx_nand.c +++ >>> b/drivers/mtd/nand/pxa3xx_nand.c @@ -480,6 +480,42 @@ static >>> void disable_int(struct pxa3xx_nand_info *info, uint32_t >>> int_mask) nand_writel(info, NDCR, ndcr | int_mask); } >>> >>> +static void drain_fifo(struct pxa3xx_nand_info *info, void >>> *data, int len) +{ + if (info->ecc_bch) { + int timeout; + + >>> /* + * According to the datasheet, when reading from NDDB + >>> * with BCH enabled, after each 32 bytes reads, we + * have to >>> make sure that the NDSR.RDDREQ bit is set. + * + * Drain >>> the FIFO 8 32 bits reads at a time, and skip + * the polling >>> on the last read. + */ + while (len > 8) { + >>> __raw_readsl(info->mmio_base + NDDB, data, 8); + + for >>> (timeout = 0; + !(nand_readl(info, NDSR) & >>> NDSR_RDDREQ); + timeout++) { + if (timeout >= 5) { + >>> dev_err(&info->pdev->dev, + "Timeout on RDDREQ while >>> draining the FIFO\n"); + return; + } + + mdelay(1); >> >> This is probably a stupid nit.. but here it goes is it any >> difference if udelay is used here? >> >> Does this makes anything better/worse? > > It doesn't make any difference. On the board I've been using, we > never hit the delay. > > So I really don't care about the number of retries and the sleep > behind them. I made these numbers up, feel free to come up with > others if it makes you more comfortable, but could we settle this? > OK, let's stop the bikeshedding. For both patches: Acked-by: Ezequiel Garcia - -- Ezequiel Garc?a, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJU5JxaAAoJEIOKbhOEIHKi9HYP/jxU75zI6QjNk1yGL7Y3qwEy M2UYrepXTwgRVRxAIN3nhGqERuBVOJCIVKlb3CUSiq9auNAO8rsRs6JTAossV781 LTUniAA0nIBFbTn/k2Wc6yGQizSy7iJRXu73MrLJrcSFO8JxFFqu04V1EYuZbh5s fuVpeLJEX8Gfy6gj85ybFs7+wkD/XnENKlnDzD6y/n4ewBC3yDPLNh436hZpEVDO ky8lYjGPHMQs0yEDcp1rfFejLAmxJ4SY6hVSKAxq3/Bn58S4y3Pgkm4cJtP8nHYe UN4q9UfOBIHWrQIVbBlViK//n3zyEtaPojDSKUiSvI2+Hmz9+eortlYEvpN1HCP3 Xqy1gzFto9FpP4Wp3KpyF609JNVUeQxAsUQZMXM6yaH2oz35szZhBq2xlIpsyo3C BDbjaYKFk3hVg+jAE0iitZW8BiZS+WZ/pzX4A8rwQBSTMcbrLTuRV611R4E/nEBL sfCwDWc1gxDDiM8pMJBGC97gwtHEibJqxES9y+T3LrhxtqPl1kUczHFDPgd3uoVw fT71PsZBtGUeOu3ysymNPc+mF9b9G9KRHYhSiOjnEIle9yvXh6kaGWv93ZM3RCUG JASv01+gqb+Bz5ZU3MMU+xjHxeoWBq7KfSWcshEHpD8QCuiZzNZ3yt0dZaYXao+M YsLlm5s62fDVILb2Q3+d =MA8V -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/