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=-4.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED autolearn=ham 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 712ACC32789 for ; Wed, 7 Nov 2018 02:56:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 212A52086A for ; Wed, 7 Nov 2018 02:56:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linaro.org header.i=@linaro.org header.b="DOt2+2N4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 212A52086A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389296AbeKGMYw (ORCPT ); Wed, 7 Nov 2018 07:24:52 -0500 Received: from mail-ed1-f66.google.com ([209.85.208.66]:44345 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388451AbeKGMYw (ORCPT ); Wed, 7 Nov 2018 07:24:52 -0500 Received: by mail-ed1-f66.google.com with SMTP id n19-v6so12210727edq.11 for ; Tue, 06 Nov 2018 18:56:28 -0800 (PST) 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=V2wcfhy5y0AiMf7u809T/U+/OgtsEImPqt6IotOeUW8=; b=DOt2+2N4aUMpcYKov6owcCWtNoxhexX+9sA/BMu35HGsVJ3zhjn555f2n2Z4IUWxW0 t61GhmaIA528S01Uk1uk5lgt4dh4KG2Fcm0zRxN1dhnDjjOUimuLjiBxp1QQ/3MPbXL/ CvjMnxJhBMtF/ncAJvu++GMwvwtFmv3hB9p8c= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=V2wcfhy5y0AiMf7u809T/U+/OgtsEImPqt6IotOeUW8=; b=ka3MP1KKLriX5LxRQ3nxDxmzzekt9sDSOvDcvxG9YP3Zhhc4JP2atZVgG+QufW2urL 2tjIQAUsBCZlxTfRFdPKrltopF8czYc93nGCbZdRn6lTMmbI66phb6bCrf40r6LHPysz 0H16V8EysRPb5GXSWbXWqmmyZgvAsmamuOTREjelXfLR7F1GP2Oh8vSNz90Bk5BmUnyu f4tx1MOtopaMVRjbSgYOqKbbAfCjDG9OcGev5T3duaj7kNODIsKnOwRWY24zyoIrKdCx 89QB55OVHM3Ear+/kCvPpoMcewH4shkucXD8jqlu+iXUUR5Iy9I0L9yUFXJEf8YzNfm0 eZdQ== X-Gm-Message-State: AGRZ1gJsQT8GdBsHPHrzVnRB4pRBfDW6gYev9oLJLgWzWlBmG9coX4mR EGXfdYXbTkrSokDtqx/SZRpgA5TQgD7guo/xuyIbZw== X-Google-Smtp-Source: AJdET5fMhhf8wTiWnIow32dHHiZ1Jx/8m7P+KK57eD095QDLcMKF92ps31Nd1J6jlg/2P4907phmqm3eBKqlerfuAK8= X-Received: by 2002:a17:906:f6cc:: with SMTP id jo12-v6mr350157ejb.66.1541559387543; Tue, 06 Nov 2018 18:56:27 -0800 (PST) MIME-Version: 1.0 References: <1541387810-24867-1-git-send-email-zhang.chunyan@linaro.org> <1541387810-24867-2-git-send-email-zhang.chunyan@linaro.org> In-Reply-To: From: Chunyan Zhang Date: Wed, 7 Nov 2018 10:56:16 +0800 Message-ID: Subject: Re: [PATCH RFC 1/3] mmc: sdhci: add support for using external DMA devices To: Arnd Bergmann Cc: Ulf Hansson , Adrian Hunter , linux-mmc@vger.kernel.org, Linux Kernel Mailing List , Mark Brown , Kishon Vijay Abraham I , Sekhar Nori , Lyra Zhang Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 6 Nov 2018 at 19:16, Arnd Bergmann wrote: > > On 11/5/18, Chunyan Zhang wrote: > > Some standard SD host controller can support both external dma > > controllers as well as ADMA in which the controller acts as > > DMA master. > > > > Currently the generic SDHCI code supports ADMA/SDMA integrated into > > the host controller but does not have any support for external DMA > > controllers implemented using dmaengine meaning that custom code is > > needed for any systems that use a generic DMA controller with SDHCI. > > > > Signed-off-by: Chunyan Zhang > > Looks good to me overall, but I think I found one small bug: > > > > + dma->rx_chan = dma_request_chan(mmc->parent, "rx"); > > + if (IS_ERR(dma->rx_chan)) { > > + ret = PTR_ERR(dma->rx_chan); > > + if (ret == -EPROBE_DEFER && dma->tx_chan) > > + dma_release_channel(dma->tx_chan); > > + > > + dma->rx_chan = NULL; > > + pr_warn("Failed to request RX DMA channel.\n"); > > + } > > The error handling looks wrong here: if you get EPROBE_DEFER, > you want to skip the warning message. If you get any other error code, Right, will address. > you want the warning message and also the dma_release_channel() > which should be unconditional here. Will address. Thanks for the review, Chunyan > > Arnd