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=-3.8 required=3.0 tests=BAYES_00, 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 976DFC433E3 for ; Wed, 26 Aug 2020 13:05:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 796C820B1F for ; Wed, 26 Aug 2020 13:05:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730176AbgHZNFH (ORCPT ); Wed, 26 Aug 2020 09:05:07 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:52356 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730163AbgHZNEs (ORCPT ); Wed, 26 Aug 2020 09:04:48 -0400 Received: from andrew by vps0.lunn.ch with local (Exim 4.94) (envelope-from ) id 1kAv6X-00BwXk-DJ; Wed, 26 Aug 2020 15:04:41 +0200 Date: Wed, 26 Aug 2020 15:04:41 +0200 From: Andrew Lunn To: Vadym Kochan Cc: David Miller , kuba@kernel.org, jiri@mellanox.com, idosch@mellanox.com, oleksandr.mazur@plvision.eu, serhiy.boiko@plvision.eu, serhiy.pshyk@plvision.eu, volodymyr.mytnyk@plvision.eu, taras.chornyi@plvision.eu, andrii.savka@plvision.eu, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, andy.shevchenko@gmail.com, mickeyr@marvell.com Subject: Re: [net-next v5 1/6] net: marvell: prestera: Add driver for Prestera family ASIC devices Message-ID: <20200826130441.GR2403519@lunn.ch> References: <20200825122013.2844-1-vadym.kochan@plvision.eu> <20200825122013.2844-2-vadym.kochan@plvision.eu> <20200825.172003.1417643181819895272.davem@davemloft.net> <20200826081744.GA2729@plvision.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200826081744.GA2729@plvision.eu> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > There is a limitation on the DMA range. Current device can't handle > whole ZONE_DMA range, so there is a "backup" mechanism which copies the > entire packet if the mapping was failed or if the packet's mapped > address is out of this range, this is done on both rx and tx directions. If you use the DMA API correct, it should hide all this, and do the bounce buffers for you. But i'm no DMA expert... Andrew