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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 264A2C433E0 for ; Fri, 29 May 2020 10:41:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 075FE208E4 for ; Fri, 29 May 2020 10:41:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725961AbgE2KlX (ORCPT ); Fri, 29 May 2020 06:41:23 -0400 Received: from mail.baikalelectronics.com ([87.245.175.226]:47250 "EHLO mail.baikalelectronics.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725601AbgE2KlX (ORCPT ); Fri, 29 May 2020 06:41:23 -0400 Received: from localhost (unknown [127.0.0.1]) by mail.baikalelectronics.ru (Postfix) with ESMTP id 7217780307C7; Fri, 29 May 2020 10:41:20 +0000 (UTC) X-Virus-Scanned: amavisd-new at baikalelectronics.ru Received: from mail.baikalelectronics.ru ([127.0.0.1]) by localhost (mail.baikalelectronics.ru [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id W6eRTeMemRWI; Fri, 29 May 2020 13:41:19 +0300 (MSK) Date: Fri, 29 May 2020 13:41:19 +0300 From: Serge Semin To: Andy Shevchenko CC: Serge Semin , Vinod Koul , Viresh Kumar , Dan Williams , Alexey Malahov , Thomas Bogendoerfer , Arnd Bergmann , Rob Herring , , , , Subject: Re: [PATCH v4 09/11] dmaengine: dw: Initialize min_burst capability Message-ID: <20200529104119.qrqoptp5iz5hs56r@mobilestation> References: <20200528222401.26941-1-Sergey.Semin@baikalelectronics.ru> <20200528222401.26941-10-Sergey.Semin@baikalelectronics.ru> <20200529102515.GD1634618@smile.fi.intel.com> <20200529102902.GG1634618@smile.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20200529102902.GG1634618@smile.fi.intel.com> X-ClientProxiedBy: MAIL.baikal.int (192.168.51.25) To mail (192.168.51.25) Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On Fri, May 29, 2020 at 01:29:02PM +0300, Andy Shevchenko wrote: > On Fri, May 29, 2020 at 01:25:15PM +0300, Andy Shevchenko wrote: > > On Fri, May 29, 2020 at 01:23:59AM +0300, Serge Semin wrote: > > > According to the DW APB DMAC data book the minimum burst transaction > > > length is 1 and it's true for any version of the controller since > > > isn't parametrised in the coreAssembler so can't be changed at the > > > IP-core synthesis stage. Let's initialise the min_burst member of the > > > DMA controller descriptor so the DMA clients could use it to properly > > > optimize the DMA requests. > > ... > > > > /* DMA capabilities */ > > > > > + dw->dma.min_burst = 1; > > > > Perhaps then relaxed maximum, like > > > > dw->dma.max_burst = 256; > > > > (channels will update this) > > > > ? > > And forgot to mention that perhaps we need a definitions for both. By "definitions for both" do you mean a macro with corresponding parameter definition like it's done for the max burst length in the next patch? Something like this: --- include/linux/platform_data/dma-dw.h +++ include/linux/platform_data/dma-dw.h +#define DW_DMA_MIN_BURST 1 +#define DW_DMA_MAX_BURST 256 ? -Sergey > > > > dw->dma.src_addr_widths = DW_DMA_BUSWIDTHS; > > > dw->dma.dst_addr_widths = DW_DMA_BUSWIDTHS; > > -- > With Best Regards, > Andy Shevchenko > >