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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 5AB92C3A59E for ; Mon, 26 Aug 2019 07:09:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 243182087E for ; Mon, 26 Aug 2019 07:09:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 243182087E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B1FD06B0531; Mon, 26 Aug 2019 03:09:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AD1BE6B0533; Mon, 26 Aug 2019 03:09:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9E7086B0534; Mon, 26 Aug 2019 03:09:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0091.hostedemail.com [216.40.44.91]) by kanga.kvack.org (Postfix) with ESMTP id 7FF036B0531 for ; Mon, 26 Aug 2019 03:09:44 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 189E4180AD7C1 for ; Mon, 26 Aug 2019 07:09:44 +0000 (UTC) X-FDA: 75863703888.10.cable47_37d6718e29a03 X-HE-Tag: cable47_37d6718e29a03 X-Filterd-Recvd-Size: 2186 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Mon, 26 Aug 2019 07:09:43 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id B04E568B02; Mon, 26 Aug 2019 09:09:39 +0200 (CEST) Date: Mon, 26 Aug 2019 09:09:39 +0200 From: Christoph Hellwig To: Nicolas Saenz Julienne Cc: catalin.marinas@arm.com, hch@lst.de, wahrenst@gmx.net, marc.zyngier@arm.com, robh+dt@kernel.org, Robin Murphy , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-arch@vger.kernel.org, iommu@lists.linux-foundation.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, Arnd Bergmann , phill@raspberryi.org, f.fainelli@gmail.com, will@kernel.org, linux-kernel@vger.kernel.org, eric@anholt.net, mbrugger@suse.com, linux-rpi-kernel@lists.infradead.org, akpm@linux-foundation.org, frowand.list@gmail.com, m.szyprowski@samsung.com Subject: Re: [PATCH v2 01/11] asm-generic: add dma_zone_size Message-ID: <20190826070939.GD11331@lst.de> References: <20190820145821.27214-1-nsaenzjulienne@suse.de> <20190820145821.27214-2-nsaenzjulienne@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190820145821.27214-2-nsaenzjulienne@suse.de> User-Agent: Mutt/1.5.17 (2007-11-01) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Aug 20, 2019 at 04:58:09PM +0200, Nicolas Saenz Julienne wrote: > Some architectures have platform specific DMA addressing limitations. > This will allow for hardware description code to provide the constraints > in a generic manner, so as for arch code to properly setup it's memory > zones and DMA mask. I know this just spreads the arm code, but I still kinda hate it. MAX_DMA_ADDRESS is such an oddly defined concepts. We have the mm code that uses it to start allocating after the dma zones, but I think that would better be done using a function returning 1 << max(zone_dma_bits, 32) or so. Then we have about a handful of drivers using it that all seem rather bogus, and one of which I think are usable on arm64.