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=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 8317DC433E7 for ; Fri, 16 Oct 2020 07:07:48 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1B0BB20720 for ; Fri, 16 Oct 2020 07:07:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="j2L2cUxy"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="waMS4eMW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B0BB20720 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=yZq+2se3HoAjcMQvlJgC3M528Fx8t0sDIRQY/AWQXrM=; b=j2L2cUxyEctK1QUuYRmuSJvHF zH6v9+IG+Q18b/4PREz2T+mSicQgrcYb3WoNHavVEuCS3cB4zsqqinzGj1j7B+j7gsDGFOTfVM8ML zftMSlS4uIReEE0U4NRLKYUqDhy1U/ARsfkEBDgzQl1udIJWxmgPFWG7uVLq0MgjsgYpa1kUck0hb hANczXK2gksUPv3hajXI886BE8VSB8GzFf9ahd64qtnO+hNftUC3clBZHBk7DaFDIaLfb5CkSkUAG 61XZZpl9P7zk+fxMTUD0xPFUMq1uKB3mSSlTE1jSfrx3sIRa7+LDTZ8CMntu396VoNkPXBJX5zsRa aquIRE2pQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kTJoq-0003FL-Cv; Fri, 16 Oct 2020 07:06:28 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kTJon-0003Ed-Ig for linux-arm-kernel@lists.infradead.org; Fri, 16 Oct 2020 07:06:26 +0000 Received: from localhost (unknown [122.182.237.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 59CC320720; Fri, 16 Oct 2020 07:06:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602831983; bh=bg+YekF+PjfIIMGx3SUCBgRM+vVNcEeNxcknchyB36I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=waMS4eMW7q+rFjqGaN2EZQEXLMHgOLzBfrw7R6RdwAlfEB9/n6PIpsBs6jZaf5kzm 2Nij6X6vzV1QsD0xXWb0KQY8b/r7YvHbR4q1jZiaay/qJJAL94oXDVdZ1eMKIaUhp1 pAYHtsjCh5KuL4SWxHy9T6cy9pClC/O1CtIKggNM= Date: Fri, 16 Oct 2020 12:36:18 +0530 From: Vinod Koul To: Eugen.Hristev@microchip.com Subject: Re: [PATCH 6/7] dt-bindings: dmaengine: at_xdmac: add optional microchip,m2m property Message-ID: <20201016070618.GW2968@vkoul-mobl> References: <20200914140956.221432-1-eugen.hristev@microchip.com> <20200914140956.221432-7-eugen.hristev@microchip.com> <20200922233327.GA3474555@bogus> <6f305564-e91c-794b-0025-de805f1d1a58@microchip.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <6f305564-e91c-794b-0025-de805f1d1a58@microchip.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201016_030625_679390_00D4DF43 X-CRM114-Status: GOOD ( 22.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: robh@kernel.org, devicetree@vger.kernel.org, Tudor.Ambarus@microchip.com, linux-kernel@vger.kernel.org, Ludovic.Desroches@microchip.com, dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Eugen, On 16-10-20, 06:45, Eugen.Hristev@microchip.com wrote: > On 23.09.2020 02:33, Rob Herring wrote: > > > On Mon, Sep 14, 2020 at 05:09:55PM +0300, Eugen Hristev wrote: > >> Add optional microchip,m2m property that specifies if a controller is > >> dedicated to memory to memory operations only. > >> > >> Signed-off-by: Eugen Hristev > >> --- > >> Documentation/devicetree/bindings/dma/atmel-xdma.txt | 6 ++++++ > >> 1 file changed, 6 insertions(+) > >> > >> diff --git a/Documentation/devicetree/bindings/dma/atmel-xdma.txt b/Documentation/devicetree/bindings/dma/atmel-xdma.txt > >> index 510b7f25ba24..642da6b95a29 100644 > >> --- a/Documentation/devicetree/bindings/dma/atmel-xdma.txt > >> +++ b/Documentation/devicetree/bindings/dma/atmel-xdma.txt > >> @@ -15,6 +15,12 @@ the dmas property of client devices. > >> interface identifier, > >> - bit 30-24: PERID, peripheral identifier. > >> > >> +Optional properties: > >> +- microchip,m2m: this controller is connected on AXI only to memory and it's > >> + dedicated to memory to memory DMA operations. If this option is > >> + missing, it's assumed that the DMA controller is connected to > >> + peripherals, thus it's a per2mem and mem2per. > > > > Wouldn't 'dma-requests = <0>' cover this case? > > > > Rob > > > > Hi Rob, > > I do not think so. With requests = 0, it means that actually the DMA > controller is unusable ? > Since you suggest requests = 0, it means that it cannot take requests at > all ? > I do not find another example in current DT with this property set to zero. Not really, dma-requests implies "request signals supported" which are used for peripheral cases. m2m does not need request signals, so it is very reasonable to conclude that dma-requests = <0> would imply no peripheral support and only m2m support. Thanks -- ~Vinod _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel