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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D745C433F5 for ; Tue, 15 Mar 2022 08:26:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231423AbiCOI2B (ORCPT ); Tue, 15 Mar 2022 04:28:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239420AbiCOI17 (ORCPT ); Tue, 15 Mar 2022 04:27:59 -0400 Received: from mx07-00178001.pphosted.com (mx08-00178001.pphosted.com [91.207.212.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 267454BFD7; Tue, 15 Mar 2022 01:26:45 -0700 (PDT) Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 22F4JVqv027247; Tue, 15 Mar 2022 09:26:03 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=selector1; bh=oDQ0bPSs1kEQPGA4aIXxaRySi/P2J26ASVpVIJPCOfw=; b=eCCUCU3ckkjg9JZogaLrJW4bezRHw/mjZBIHhc9DDxaL78yvZ/BafbdZQPDnl81zrBbw oD5Gnarfz/xDPmKyulwxiKLb/EbAgrir1PJgnqCHblXu6B7r2oIUym5/jte3hgVn0ZlC niCX3zel4DKTke6eYb2627c/hzZxLkv83G93CX5zcfSvIRDqklqNW817kvikFPt1d401 A8FBfs3AEfWbl/SO0C4Wc1cnYBa2tTz6iiS+VhI2ezSrgY9NxOnn7GY6y0wCOmikD/Fr 3SKmphfBhfhbn14vDgjV+W6Hy2LCFfF3DeHYksxjqaeecvvQu6c+4G918U/XsxG8+Z38 bw== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com (PPS) with ESMTPS id 3etj2ahghy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 15 Mar 2022 09:26:03 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 8560B10002A; Tue, 15 Mar 2022 09:26:02 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag2node2.st.com [10.75.127.5]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 7B789212FC5; Tue, 15 Mar 2022 09:26:02 +0100 (CET) Received: from [10.201.21.172] (10.75.127.46) by SFHDAG2NODE2.st.com (10.75.127.5) with Microsoft SMTP Server (TLS) id 15.0.1497.26; Tue, 15 Mar 2022 09:26:01 +0100 Message-ID: <0bc53018-fce4-4104-fa47-6e60d2367d69@foss.st.com> Date: Tue, 15 Mar 2022 09:26:01 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH 1/3] dt-bindings: mmc: mmci: add a property to disable DMA LLI Content-Language: en-US To: Linus Walleij CC: Rob Herring , Ulf Hansson , , , , , , Alexandre Torgue , Christophe Kerello , Ludovic Barre , Maxime Coquelin , Philipp Zabel , Russell King , Marek Vasut , , Manivannan Sadhasivam , Grzegorz Szymaszek References: <20220304135134.47827-1-yann.gautier@foss.st.com> <20220304135134.47827-2-yann.gautier@foss.st.com> From: Yann Gautier In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.46] X-ClientProxiedBy: SFHDAG2NODE2.st.com (10.75.127.5) To SFHDAG2NODE2.st.com (10.75.127.5) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-14_14,2022-03-14_02,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/14/22 23:43, Linus Walleij wrote: > "On Fri, Mar 4, 2022 at 2:52 PM Yann Gautier wrote: > >> On STMicroelectronics variant of PL18x, the DMA Linked Lists are supported >> starting from revision v2 of the peripheral. But it has limitations, >> as all the buffers should be aligned on block size (except the last one). >> But this cannot be guaranteed with SDIO. We should then have a property >> to disable the support of LLI. >> >> Signed-off-by: Yann Gautier > > Actually I think this is present also on the ux500 variants. See: > commit 2253ed4b36dc876d1598c4dab5587e537ec68c34 > "mmc: mmci: Support any block sizes for ux500v2 and qcom variant" > > Spot the variant data "dma_power_of_2". > > So whatever property you add > to the variant data (not in the device tree please) should > be added to the ux500 variants as well, it will *VERY* likely > have a problem with LLI elements not being a power of 2 > as it is the ancestor of later STMicro variants. > > It might actually be the reason for some annoying WiFi error > messages I have seen :/ > > Yours, > Linus Walleij Hi Linus, The STM32 variant uses an internal DMA, and the DMA functions are in its dedicated file. So I was planning to do the same as what is done in meson-gx-mmc.c: using a bounce buffer to copy from/to in case DMA constraints are not fulfilled. Not sure it can help for Ux500. Ulf, before I send my new series (although it is not ready yet), would you be OK with the bounce buffer idea? Best regards, Yann