From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752656AbcERKxN (ORCPT ); Wed, 18 May 2016 06:53:13 -0400 Received: from mout.kundenserver.de ([212.227.126.135]:59855 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751492AbcERKxK (ORCPT ); Wed, 18 May 2016 06:53:10 -0400 From: Arnd Bergmann To: linux-arm-kernel@lists.infradead.org Cc: Alexander Graf , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Sinan Kaya , Eric Anholt Subject: Re: [PATCH] arm64: Allow for different DMA and CPU bus offsets Date: Wed, 18 May 2016 12:52:28 +0200 Message-ID: <12218676.p29ELivsix@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1463563981-69722-1-git-send-email-agraf@suse.de> References: <1463563981-69722-1-git-send-email-agraf@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:+jxaRPU9S71L+VYrPaEMawn0FLxUkMrwXSN08QCw82aHHl08VJU pGYRtp5ILxFZ4WsbQvCDCcUvK2XduOxkbLPf3zlbzbtJLdQUWOTGxIKzsDSr29Wgdq21xi1 8hbuJ5YcQAi5eQbcldqSdfEDD5fToef9m9ozqC3Afx4bEbpoTKlEB8AnhQlNcEWGuU4UQkD tyNTxxbOvByXpNrKnrYYw== X-UI-Out-Filterresults: notjunk:1;V01:K0:79g4eFbcTjI=:zyAQ3CdGHv8XTf5O3oHF9E 0Z8PV/xpRjM8dIB2ZN2fWtZdSneT8CDoAK58MVv6yfbr7gr4AUmVzrIwerDrt3tJfUjbgXRU0 +dlvSfn4+Pjc7awWI7EbIFAAlGmxvMDp6eKJJn/jOssfgEa3+j2JI/0ips91+fQ1s84nGBhP8 zLlF27W1oe/iJSoAqe+5tIpwFYhhxUJx0vV3Tw/cuo60GRiH1hEOZtWHtynK+ccSeu3ovQM+i hLQ4hby1/3Pj9dM4IG0fz2yyOhMnswSFsWbF5yZMSC0Vn8oF3uBdfX5MH/zTQ14tPs0Vv2MMY 0yVt/CNHXMOwVB5rWffRNEBAM2Sa361/d+FoW+KuCHu1Uen/oWF80Vwxb1E5+K6je1eyfUsAE S840ebxCZfXe2wRfo9dYonhe/MFhdckqU6hSoMDdZjPCn2aEEqbZNUavX5rjuLGQIjqmoihRw gshNauREW+/4ZKoh7NZRu8PmKi9d55oMm9Cr6h0Q/r+m8SEejV/b6GJHnKO4nbpf9hAjRQJRL sQG3HlctujgEuXoyrHub/wMTy/49M859QFRN0lfJT0V8o5qHmFprfu2hzi41xdZER72oWwgKL 9AwfJoOTZtkIDXOHHzHq0QPIKo7QX3ylrVeOj+04EzJtatStWMuZjIBIdcj4Qus37XiMbrOa0 tk4H+W0TDZg7NkQopIG0cbMhQ486hN2gc/a1dZ8DWcVo9iuJ9a6v/qPl3BRY1hVBFSA/N8HEN 2mxv/f91dqNGN79h Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 18 May 2016 11:33:01 Alexander Graf wrote: > diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h > index ba437f0..67bf8e1 100644 > --- a/arch/arm64/include/asm/dma-mapping.h > +++ b/arch/arm64/include/asm/dma-mapping.h > @@ -66,12 +66,16 @@ static inline bool is_device_dma_coherent(struct device *dev) > > static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr) > { > - return (dma_addr_t)paddr; > + dma_addr_t dev_addr = (dma_addr_t)paddr; > + > + return dev_addr - (dma_addr_t)__pfn_to_phys(dev->dma_pfn_offset); > } > > static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr) > { > - return (phys_addr_t)dev_addr; > + phys_addr_t paddr = (phys_addr_t)dev_addr; > + > + return paddr + __pfn_to_phys(dev->dma_pfn_offset); > } > The patch looks ok overall, but I think it's better to use an open-coded shift instead of __pfn_to_phys/__pfn_to_phys here: those helpers convert between actual page frame numbers and addresses, which may not always be a 1:1 relationship, e.g. if someone wants to work around the crazy "Principles of ARM Memory Maps White Paper" layout. Arnd