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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 BCCB8C433E2 for ; Mon, 29 Jun 2020 21:36:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9AB8520759 for ; Mon, 29 Jun 2020 21:36:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593466567; bh=LXvcRe88NweP1KRH4lrxCsBpxttGet8FB2YNmIkHxnc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=KhDgmzBQE9cVe4SN81qLHv+hE408WQ2LKcI68eh36RopcQLBsgmpYHUgSvIDunnow a3uQ/EFFFO0rq1RT5Fr2e5+nOJ+nzoquWngjYxAjwfxjjZFy+q9Shfk9Xsf9NNW1SD 8qwRSP1Z/UOPrR7a6IyiUOP5aPzUNFyuyNVkjjdQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728491AbgF2Vf7 (ORCPT ); Mon, 29 Jun 2020 17:35:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:60646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728486AbgF2Skp (ORCPT ); Mon, 29 Jun 2020 14:40:45 -0400 Received: from localhost (unknown [122.182.251.219]) (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 7D02523D50; Mon, 29 Jun 2020 13:21:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593436905; bh=LXvcRe88NweP1KRH4lrxCsBpxttGet8FB2YNmIkHxnc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lk8z7Qeu0qofDn4k3ukyl8Sgf9/l0vRWVNNaxxiLCWKdrrkSPK6sw9oFTo8sGJd1R 8PFulkOmFfu4BtOELvFb+dYXpcL58MVebjO7CQKYydYCX0IlDe0Gf+7yT9rjRPWn6R CZCP4xfFBBzpmAeGfiSw66I6ySQrWvLzT2eJBH/s= Date: Mon, 29 Jun 2020 18:51:41 +0530 From: Vinod Koul To: =?iso-8859-1?Q?Andr=E9?= Przywara Cc: Amit Singh Tomar , afaerber@suse.de, manivannan.sadhasivam@linaro.org, dan.j.williams@intel.com, cristian.ciocaltea@gmail.com, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-actions@lists.infradead.org Subject: Re: [PATCH v4 02/10] dmaengine: Actions: Add support for S700 DMA engine Message-ID: <20200629132141.GM2599@vkoul-mobl> References: <1591697830-16311-1-git-send-email-amittomer25@gmail.com> <1591697830-16311-3-git-send-email-amittomer25@gmail.com> <20200624061529.GF2324254@vkoul-mobl> <75d154d0-2962-99e6-a7c7-bf0928ec8b2a@arm.com> <20200629095446.GH2599@vkoul-mobl> <36274785-f400-4d69-deed-b7d545718d40@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <36274785-f400-4d69-deed-b7d545718d40@arm.com> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 29-06-20, 12:19, André Przywara wrote: > On 29/06/2020 10:54, Vinod Koul wrote: > >> What newer SoCs? I don't think we should try to guess the future here. > > > > In a patch for adding new SoC, quite ironical I would say! > > S700 is not a new SoC, it's just this driver didn't support it yet. What > I meant is that I don't even know about the existence of upcoming SoCs > (Google seems clueless), not to speak of documentation to assess which > DMA controller they use. > > >> We can always introduce further abstractions later, once we actually > >> *know* what we are looking at. > > > > Rather if we know we are adding abstractions, why not add in a way that > > makes it scale better rather than rework again > > I appreciate the effort, but this really tapping around in the dark, > since we don't know which direction any new DMA controller is taking. I > might not even be similar. > > >> Besides, I don't understand what you are after. The max frame length is > >> 1MB in both cases, it's just a matter of where to put FCNT_VAL, either > >> in FLEN or in CTRLB. And having an extra flag for that in driver data > >> sounds a bit over the top at the moment. > > > > Maybe, maybe not. I would rather make it support N SoC when adding > > support for second one rather than keep adding everytime a new SoC is > > added... > > Well, what do you suggest, specifically? At the moment we have two > *slightly* different DMA controllers, so we differentiate between the > two based on the model. Do you want to introduce an extra flag like > FRAME_CNT_IN_CTRLB? That seems to be a bit over the top here, since we > don't know if a future DMA controller is still compatible, or introduces > completely new differences. Fair enough, okay let us go with compatible for now -- ~Vinod