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 93470C433EF for ; Fri, 25 Mar 2022 20:12:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231197AbiCYUN5 (ORCPT ); Fri, 25 Mar 2022 16:13:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231261AbiCYUN4 (ORCPT ); Fri, 25 Mar 2022 16:13:56 -0400 Received: from mail-yw1-x1129.google.com (mail-yw1-x1129.google.com [IPv6:2607:f8b0:4864:20::1129]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 458DF46640 for ; Fri, 25 Mar 2022 13:12:21 -0700 (PDT) Received: by mail-yw1-x1129.google.com with SMTP id 00721157ae682-2e612af95e3so94230507b3.9 for ; Fri, 25 Mar 2022 13:12:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=YT2o1xxdFf9OVHBJJGoL9aS2UVDgV96wgaPQnf59u3A=; b=iUDT/G3LEcGf/5tagjP8eFjsGsyOBph1oCwiAU9SRpn47LJA8MWoC2ZnwxrjbSPjMm NMgbwZLb++g0JJFq9rSNRDfuiuAAY8Rb8mEl15bFUi/1axDz0mqVDBjWIOF7rWkJktPB GVLthy7ZRekp5ux4Y2DFI5hfRTVn6an7IoJvpEJSJ/9e6g+VV6/TIh6v+e0YKsPg/ANl u9+Q/qattDvEkHp5i6SesaOU1SOYG0BE3BKYCSAklaOO+5ljSccec5A3gP/LLOHHRLHW 2IrIx4x8ygD2EPSpIa9BNu8dVIUcFM2jbwLpeByGektKecBFHNoOwvOwoDpGWDgslNFr atGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=YT2o1xxdFf9OVHBJJGoL9aS2UVDgV96wgaPQnf59u3A=; b=AR0S7Cf36uC5j6nnmJXSjDWF63MDcGAcPTdcBc88mAJJNTpyLQ10DQ8oZiyhuNB8Kn yehzYTPR+hVXtxsWRJAVYwQ/qTsErvRF1NTxFKenoXfiY+j4Il01d6EbOmTFIJVsHOWo XfRGThEH1tn84gST/aci6psvf5OqtpcusbQeB5phxHoLQjAWsUPar/IwvMhpEsMxnNdg 81TcGI93SSJpN8qvgdIelVMbyKmyK2ftkXf+g/d7Hfy9be6o96TPlYxiUUr9bp4DVZi0 BlADWkPgZUKYvCUsinl8u22m/0uvskch650lf8jsdmj4iXs/a3mzsKO6svez20dwxY7h r1aQ== X-Gm-Message-State: AOAM531tHU7Sr6Q8vjHWZiwKS9NWPVBvaBTl1HzNcGTSI6706QJuNzRN tMBP8eWJVMOgNqKJdmMMwFb8OH23rY7etMb7a+YXvw== X-Google-Smtp-Source: ABdhPJxUBffdaPMdxHWCaYq0Qr6rteF2S4TUamYdP1nuniOmrgv1lq5txO6UeJxGVYZr0OiLkvNRfbesOoqWq1bIo24= X-Received: by 2002:a81:164a:0:b0:2e6:8e4b:7487 with SMTP id 71-20020a81164a000000b002e68e4b7487mr12654258yww.437.1648239140546; Fri, 25 Mar 2022 13:12:20 -0700 (PDT) MIME-Version: 1.0 References: <20220304135134.47827-1-yann.gautier@foss.st.com> <20220304135134.47827-2-yann.gautier@foss.st.com> <0bc53018-fce4-4104-fa47-6e60d2367d69@foss.st.com> In-Reply-To: <0bc53018-fce4-4104-fa47-6e60d2367d69@foss.st.com> From: Linus Walleij Date: Fri, 25 Mar 2022 21:12:09 +0100 Message-ID: Subject: Re: [PATCH 1/3] dt-bindings: mmc: mmci: add a property to disable DMA LLI To: Yann Gautier Cc: Rob Herring , Ulf Hansson , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, Alexandre Torgue , Christophe Kerello , Ludovic Barre , Maxime Coquelin , Philipp Zabel , Russell King , Marek Vasut , kernel@dh-electronics.com, Manivannan Sadhasivam , Grzegorz Szymaszek Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, Mar 15, 2022 at 9:26 AM Yann Gautier wrote: > 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? Would it not be better if the bounce buffer is something available for all MMCI variants and not restricted to the STM32 DMA add-on? What I'm thinking is that this is a problem with the MMCI hardware rather than with the DMA hardware, so the problem kind of gets fixed in the wrong place if the bounce buffer is in the DMA add-on code. Maybe this is how you fixed it in later patches, I'll take a look. Yours, Linus Walleij