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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 4C911C2D0E1 for ; Fri, 11 Sep 2020 06:25:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 193E822204 for ; Fri, 11 Sep 2020 06:25:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725562AbgIKGZR (ORCPT ); Fri, 11 Sep 2020 02:25:17 -0400 Received: from verein.lst.de ([213.95.11.211]:35640 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725535AbgIKGZQ (ORCPT ); Fri, 11 Sep 2020 02:25:16 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 9D35867373; Fri, 11 Sep 2020 08:25:12 +0200 (CEST) Date: Fri, 11 Sep 2020 08:25:12 +0200 From: Christoph Hellwig To: Robin Murphy Cc: Christoph Hellwig , iommu@lists.linux-foundation.org, Russell King , Santosh Shilimkar , devicetree@vger.kernel.org, Florian Fainelli , linux-sh@vger.kernel.org, Frank Rowand , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, Rob Herring , Jim Quinlan , linux-pci@vger.kernel.org, Nathan Chancellor , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/3] ARM/dma-mapping: move various helpers from dma-mapping.h to dma-direct.h Message-ID: <20200911062512.GC21597@lst.de> References: <20200910054038.324517-1-hch@lst.de> <20200910054038.324517-2-hch@lst.de> <42497691-ec93-1e93-d3e5-e841eaf8247a@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <42497691-ec93-1e93-d3e5-e841eaf8247a@arm.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, Sep 10, 2020 at 07:02:23PM +0100, Robin Murphy wrote: > On 2020-09-10 06:40, Christoph Hellwig wrote: >> Move the helpers to translate to and from direct mapping DMA addresses >> to dma-direct.h. This not only is the most logical place, but the new >> placement also avoids dependency loops with pending commits. > > For the straightforward move as it should be, > > Reviewed-by: Robin Murphy > > However I do wonder how much of this could be cleaned up further... >> + >> +#ifdef __arch_page_to_dma >> +#error Please update to __arch_pfn_to_dma >> +#endif > > This must be long, long dead by now. Yeah. I had a patch to remove this which lead me into the rabbit hole your described later. A few patches in I decided to give up and just do the trivial move. But it probably makes sense to pick up at least the two trivial dead code removal patches.. >> +static inline unsigned long dma_to_pfn(struct device *dev, dma_addr_t addr) >> +{ >> + unsigned long pfn = __bus_to_pfn(addr); >> + >> + if (dev) >> + pfn += dev->dma_pfn_offset; >> + >> + return pfn; >> +} > > These are only overridden for OMAP1510, and it looks like it wouldn't take > much for the platform code or ohci-omap driver to set up a generic DMA > offset for the relevant device. I sent a ping to the omap maintainers earlier this week to ask for that :) >> +static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) >> +{ >> + if (dev) >> + return pfn_to_dma(dev, virt_to_pfn(addr)); >> + >> + return (dma_addr_t)__virt_to_bus((unsigned long)(addr)); >> +} > > And this is only used for some debug prints in dmabounce. > > Similarly the __bus_to_*()/__*_to_bus() calls themselves only appear > significant to mach-footbridge any more, and could probably also be evolved > into regular DMA offsets now that all API calls must have a non-NULL > device. I think I might come back and take a closer look at all this at > some point in future... :) Yes, pretty much all of this should eventually go away. I just don't want to bock the ranges work on all kinds of random arm cleanups..