From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55B0CC433DF for ; Mon, 24 Aug 2020 12:49:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 33CD320706 for ; Mon, 24 Aug 2020 12:49:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726952AbgHXMtx (ORCPT ); Mon, 24 Aug 2020 08:49:53 -0400 Received: from goliath.siemens.de ([192.35.17.28]:53242 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725904AbgHXMts (ORCPT ); Mon, 24 Aug 2020 08:49:48 -0400 Received: from mail2.sbs.de (mail2.sbs.de [192.129.41.66]) by goliath.siemens.de (8.15.2/8.15.2) with ESMTPS id 07OCnNt2009655 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 24 Aug 2020 14:49:24 +0200 Received: from [167.87.131.75] ([167.87.131.75]) by mail2.sbs.de (8.15.2/8.15.2) with ESMTP id 07OCnIUn004790; Mon, 24 Aug 2020 14:49:20 +0200 Subject: Re: [RESEND PATCH v3 5/8] mtd: spi-nor: cadence-quadspi: Handle probe deferral while requesting DMA channel To: Vignesh Raghavendra , Tudor Ambarus , Mark Brown , "Jin, Le (RC-CN DF FA R&D)" Cc: Boris Brezillon , Ramuthevar Vadivel Murugan , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, simon.k.r.goldschmidt@gmail.com, dinguyen@kernel.org, marex@denx.de References: <20200601070444.16923-1-vigneshr@ti.com> <20200601070444.16923-6-vigneshr@ti.com> <6c8d9bff-3a67-0e6c-d4d1-36b7ed5007b9@web.de> <8cebd31a-2366-4584-b1d1-faa30c18ed6a@ti.com> From: Jan Kiszka Message-ID: Date: Mon, 24 Aug 2020 14:49:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <8cebd31a-2366-4584-b1d1-faa30c18ed6a@ti.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24.08.20 13:45, Vignesh Raghavendra wrote: > > > On 8/22/20 11:35 PM, Jan Kiszka wrote: >> On 01.06.20 09:04, Vignesh Raghavendra wrote: >>> dma_request_chan_by_mask() can throw EPROBE_DEFER if DMA provider >>> is not yet probed. Currently driver just falls back to using PIO mode >>> (which is less efficient) in this case. Instead return probe deferral >>> error as is so that driver will be re probed once DMA provider is >>> available. >>> >>> Signed-off-by: Vignesh Raghavendra >>> Reviewed-by: Tudor Ambarus >>> --- > [...] >>> >>> static const struct spi_nor_controller_ops cqspi_controller_ops = { >>> @@ -1269,8 +1274,11 @@ static int cqspi_setup_flash(struct cqspi_st *cqspi, struct device_node *np) >>> dev_dbg(nor->dev, "using direct mode for %s\n", >>> mtd->name); >>> >>> - if (!cqspi->rx_chan) >>> - cqspi_request_mmap_dma(cqspi); >>> + if (!cqspi->rx_chan) { >>> + ret = cqspi_request_mmap_dma(cqspi); >>> + if (ret == -EPROBE_DEFER) >>> + goto err; >>> + } >>> } >>> } >>> >>> >> >> This seem to break reading the SPI flash on our IOT2050 [1] (didn't test >> the eval board yet). >> >> Without that commit, read happens via PIO, and that works. With the >> commit, the pattern >> >> with open("out.bin", "wb") as out: >> pos = 0 >> while pos < 2: >> with open("/dev/mtd0", "rb") as mtd: >> mtd.seek(pos * 0x10000) >> out.write(mtd.read(0x10000)) >> pos += 1 >> >> gives the wrong result for the second block while > > Interesting... Could you please explain wrong result? Is the data move > around or completely garbage? It looks like some stripes contain data from other parts of the flash or kernel RAM. It's not just garbage, there are readable strings included. > > Does this fail even on AM654 EVM? Could you share full script for me to > test locally? The scripts are complete (python). Just binary-diff the outputs. I'll try on the EVM later. > > What is the flash on the board? Le, could you answer that more precisely than I could? Thanks, Jan > >> >> with open("out2.bin", "wb") as out: >> with open("/dev/mtd0", "rb") as mtd: >> out.write(mtd.read(0x20000)) >> >> (or "mtd_debug read") is fine. >> >> What could be the reason? Our DTBs and k3-am654-base-board.dtb had some >> deviations /wrt the ospi node, but aligning ours to the base board made >> no difference. >> >> Jan >> >> [1] https://github.com/siemens/linux/commits/jan/iot2050 >> -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux