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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 E89B6C32751 for ; Wed, 31 Jul 2019 15:17:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8EB8208E3 for ; Wed, 31 Jul 2019 15:17:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564586245; bh=QLtbVtyJYSI7n5fVnkziSsOezk9bUyYirENwCfguXxI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=nbnaBwjAXlVfPFCW519O18xygKJ7vZJHWocjwDXcbDg7nJKDqldVcm24rj7YK0Sr7 /w/YJD9GSWijhPC/N5mxlFa8yFm61sCN0L//eHsbIBnFd2NEzNgKUmZEOxC6MkLnTT T+h71tpHBDYd35F2I0VRsbPBdVYzcBYnd6+CDWMA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727370AbfGaPRZ (ORCPT ); Wed, 31 Jul 2019 11:17:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:59896 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726859AbfGaPRZ (ORCPT ); Wed, 31 Jul 2019 11:17:25 -0400 Received: from localhost (unknown [171.76.116.36]) (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 043D5206A2; Wed, 31 Jul 2019 15:17:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564586244; bh=QLtbVtyJYSI7n5fVnkziSsOezk9bUyYirENwCfguXxI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lbzuLgqb5ns6zxuRild0zWDqNUDFQPIZGJ7Fb4av46TQnhuG4/wrb4hZprvP0cT8C KU54V3L8FjH2uk6USMAu/AM6/lP3w++MBb24XnXqobPpgHMhRa9xX9wl//+hHhJmL9 UwPz49l5flgfdOFWG4taG3u0nQVUH5cC37Tngm5M= Date: Wed, 31 Jul 2019 20:46:10 +0530 From: Vinod Koul To: Jon Hunter Cc: Sameer Pujar , Peter Ujfalusi , dan.j.williams@intel.com, tiwai@suse.com, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, sharadg@nvidia.com, rlokhande@nvidia.com, dramesh@nvidia.com, mkumard@nvidia.com Subject: Re: [PATCH] [RFC] dmaengine: add fifo_size member Message-ID: <20190731151610.GT12733@vkoul-mobl.Dlink> References: <09929edf-ddec-b70e-965e-cbc9ba4ffe6a@nvidia.com> <20190618043308.GJ2962@vkoul-mobl> <23474b74-3c26-3083-be21-4de7731a0e95@nvidia.com> <20190624062609.GV2962@vkoul-mobl> <75be49ac-8461-0798-b673-431ec527d74f@nvidia.com> <20190719050459.GM12733@vkoul-mobl.Dlink> <3e7f795d-56fb-6a71-b844-2fc2b85e099e@nvidia.com> <20190729061010.GC12733@vkoul-mobl.Dlink> <98954eb3-21f1-6008-f8e1-f9f9b82f87fb@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <98954eb3-21f1-6008-f8e1-f9f9b82f87fb@nvidia.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 31-07-19, 10:48, Jon Hunter wrote: > > On 29/07/2019 07:10, Vinod Koul wrote: > > On 23-07-19, 11:24, Sameer Pujar wrote: > >> > >> On 7/19/2019 10:34 AM, Vinod Koul wrote: > >>> On 05-07-19, 11:45, Sameer Pujar wrote: > >>>> Hi Vinod, > >>>> > >>>> What are your final thoughts regarding this? > >>> Hi sameer, > >>> > >>> Sorry for the delay in replying > >>> > >>> On this, I am inclined to think that dma driver should not be involved. > >>> The ADMAIF needs this configuration and we should take the path of > >>> dma_router for this piece and add features like this to it > >> > >> Hi Vinod, > >> > >> The configuration is needed by both ADMA and ADMAIF. The size is > >> configurable > >> on ADMAIF side. ADMA needs to know this info and program accordingly. > > > > Well I would say client decides the settings for both DMA, DMAIF and > > sets the peripheral accordingly as well, so client communicates the two > > sets of info to two set of drivers > > That maybe, but I still don't see how the information is passed from the > client in the first place. The current problem is that there is no means > to pass both a max-burst size and fifo-size to the DMA driver from the > client. So one thing not clear to me is why ADMA needs fifo-size, I thought it was to program ADMAIF and if we have client programme the max-burst size to ADMA and fifo-size to ADMAIF we wont need that. Can you please confirm if my assumption is valid? > IMO there needs to be a way to pass vendor specific DMA configuration > (if this information is not common) otherwise we just end up in a > scenario like there is for the xilinx DMA driver > (include/linux/dma/xilinx_dma.h) that has a custom API for passing this > information. > > Cheers > Jon > > -- > nvpublic -- ~Vinod