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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 C2962C433E8 for ; Tue, 14 Jul 2020 16:18:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC88E2251F for ; Tue, 14 Jul 2020 16:18:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727984AbgGNQSS (ORCPT ); Tue, 14 Jul 2020 12:18:18 -0400 Received: from mga05.intel.com ([192.55.52.43]:55862 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725876AbgGNQSS (ORCPT ); Tue, 14 Jul 2020 12:18:18 -0400 IronPort-SDR: qUaFIV6Ek4VO4F7jEEhBqUESBD1o+iItkVztJPDxdKUcyu5RrtBvgiISvltaqHUefzZQY5wys9 zLs2xqSzJbsg== X-IronPort-AV: E=McAfee;i="6000,8403,9681"; a="233813989" X-IronPort-AV: E=Sophos;i="5.75,350,1589266800"; d="scan'208";a="233813989" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2020 09:18:18 -0700 IronPort-SDR: HN+vpBCYu9KmC3INIgKGNBMsFh/JR6Q0OcGv5RbozxfE74tRKkf9WfaIPnZmBleoc/bK7AUnqY E86DQqdVbCDQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,350,1589266800"; d="scan'208";a="307928997" Received: from djiang5-mobl1.amr.corp.intel.com (HELO [10.209.140.223]) ([10.209.140.223]) by fmsmga004.fm.intel.com with ESMTP; 14 Jul 2020 09:18:17 -0700 Subject: Re: [PATCH v7 05/11] dmaengine: Introduce DMA-device device_caps callback To: Vinod Koul Cc: Serge Semin , Andy Shevchenko , Viresh Kumar , Dan Williams , Alexey Malahov , Thomas Bogendoerfer , Arnd Bergmann , Rob Herring , linux-mips@vger.kernel.org, devicetree@vger.kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200709224550.15539-1-Sergey.Semin@baikalelectronics.ru> <20200709224550.15539-6-Sergey.Semin@baikalelectronics.ru> <20200710084503.GE3703480@smile.fi.intel.com> <20200710093834.su3nsjesnhntpd6d@mobilestation> <07d4a977-1de6-b611-3d4f-7c7d6cd7fe5f@intel.com> <20200714160830.GL34333@vkoul-mobl> From: Dave Jiang Message-ID: Date: Tue, 14 Jul 2020 09:18:16 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200714160830.GL34333@vkoul-mobl> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 7/14/2020 9:08 AM, Vinod Koul wrote: > On 13-07-20, 13:55, Dave Jiang wrote: >> >> >> On 7/10/2020 2:38 AM, Serge Semin wrote: >>> On Fri, Jul 10, 2020 at 11:45:03AM +0300, Andy Shevchenko wrote: >>>> On Fri, Jul 10, 2020 at 01:45:44AM +0300, Serge Semin wrote: >>>>> There are DMA devices (like ours version of Synopsys DW DMAC) which have >>>>> DMA capabilities non-uniformly redistributed between the device channels. >>>>> In order to provide a way of exposing the channel-specific parameters to >>>>> the DMA engine consumers, we introduce a new DMA-device callback. In case >>>>> if provided it gets called from the dma_get_slave_caps() method and is >>>>> able to override the generic DMA-device capabilities. >>>> >>> >>>> In light of recent developments consider not to add 'slave' and a such words to the kernel. >>> >>> As long as the 'slave' word is used in the name of the dma_slave_caps >>> structure and in the rest of the DMA-engine subsystem, it will be ambiguous >>> to use some else terminology. If renaming needs to be done, then it should be >>> done synchronously for the whole subsystem. >> >> What about just calling it dma_device_caps? Consider this is a useful >> function not only slave DMA will utilize this. I can see this being useful >> for some of my future code with idxd driver. > > Some of the caps may make sense to generic dmaengine but few of them do > not :) While at it, am planning to make it dmaengine_periph_caps to > denote that these are dmaengine peripheral capabilities. > If the function only passes in periph_caps, how do we allow the non periph DMA utilize this function?