From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752989AbcD0OMH (ORCPT ); Wed, 27 Apr 2016 10:12:07 -0400 Received: from mout.kundenserver.de ([212.227.126.131]:55308 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752883AbcD0OMD (ORCPT ); Wed, 27 Apr 2016 10:12:03 -0400 From: Arnd Bergmann To: Catalin Marinas Cc: Felipe Balbi , Grygorii Strashko , Greg Kroah-Hartman , Yoshihiro Shimoda , linux-usb@vger.kernel.org, Sekhar Nori , linux-kernel@vger.kernel.org, David Fisher , "Thang Q. Nguyen" , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev Date: Wed, 27 Apr 2016 16:11:17 +0200 Message-ID: <9452408.uEOOA4q1YW@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <20160427135859.GC20646@e104818-lin.cambridge.arm.com> References: <1461612094-30939-1-git-send-email-grygorii.strashko@ti.com> <878tzzpq19.fsf@intel.com> <20160427135859.GC20646@e104818-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:/i/u57eZRWM24yIWdQFb93kV8wVNjfjXMYCTX9lMJOUVrY8VN2A 87irD9W9rrap6zzPlc17/xr7cZJOiL18Uk08I20H9dbPAwDxEBMVgiiljIyHC62v53hAPF+ g+syP/F32Mk7Fj5IjZxPJeSCf76LRqwNWo75JP8zzaIqlUHNIsg2uPjfqDJWD/qCTbdG7bC N6/IE2IS6mCct+3bnHqFw== X-UI-Out-Filterresults: notjunk:1;V01:K0:GOQRRFc0SX0=:hTJjZ5FgEkxOtispC1/z8M oqr+V/74MioFPvoO5wEVGXM+KcR/lsOYl/+9LpBFboLOzqPjFOV3OElwImTgEGHomr/YUpLi6 J9U1FPMnMcmdS0bYIkEw+mIGtNXvjBuvb7rl7xteMnOCRz5oy2ZZm34EnUD7SUSC34VqI5beB DO4OnPgSKQOYhN0pOEdN5ulavY9x3PZmMKJdHZl/Mpy+pRrE3FyVCLV1TPuc7fVQBhV/P5E8C BcGebvpMyDrpcND5V2UppHGxzk63fqy5aXxpMQ3RQgMC72H3Tg4ZQSsU6A6hl5uYo1jvb8etS IMdbA+LH0eLo3csVYX9Ov+hyxY5phHwbMdo/Agx29RySylihn87fluEufsdAzDkkmQsVa60Qu hrMS+9iapNwtk+YtlvDvcyAcBVC59jtXr1iSHg2csF7bZ3y9pqrx1DJGKwdzZKYxKo2RlgJS9 2haBK+desCt39S90N8uIjFVQXZVioaU/PltFfUo/ayxUvgpeZ661LSiOrRTEMAwhowLZpP0jB cSSLzYUJQmVGyEOyhL74Ph3xW1s3CqcDsA6Vd708bP3cmuja7jDZlS4a0F1UOGPkx/jwYUE2E V+tkvil5FZ0nyrlcsbRJSIWp+cPgB/5vb3Ic5rFCusN+8hs8z05JBaXJ3koaATNLhSCUriXTe cAcSRJXT3GtVub3g9mugHVbLb8LelpkuktVTYFUtGG6/jJPcedHvhdCMMlZi/Qcf3YWSwUy2u XFSdq8R2RtlNgYyw Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 27 April 2016 14:59:00 Catalin Marinas wrote: > > I would be in favour of a dma_inherit() function as well. We could hack > something up in the arch code (like below) but I would rather prefer an > explicit dma_inherit() call by drivers creating such devices. > > diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h > index ba437f090a74..ea6fb9b0e8fa 100644 > --- a/arch/arm64/include/asm/dma-mapping.h > +++ b/arch/arm64/include/asm/dma-mapping.h > @@ -29,8 +29,11 @@ extern struct dma_map_ops dummy_dma_ops; > > static inline struct dma_map_ops *__generic_dma_ops(struct device *dev) > { > - if (dev && dev->archdata.dma_ops) > - return dev->archdata.dma_ops; > + while (dev) { > + if (dev->archdata.dma_ops) > + return dev->archdata.dma_ops; > + dev = dev->parent; > + } I think this would be a very bad idea: we don't want to have random devices be able to perform DMA just because their parent devices have been set up that way. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Wed, 27 Apr 2016 16:11:17 +0200 Subject: [PATCH] usb: dwc3: host: inherit dma configuration from parent dev In-Reply-To: <20160427135859.GC20646@e104818-lin.cambridge.arm.com> References: <1461612094-30939-1-git-send-email-grygorii.strashko@ti.com> <878tzzpq19.fsf@intel.com> <20160427135859.GC20646@e104818-lin.cambridge.arm.com> Message-ID: <9452408.uEOOA4q1YW@wuerfel> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wednesday 27 April 2016 14:59:00 Catalin Marinas wrote: > > I would be in favour of a dma_inherit() function as well. We could hack > something up in the arch code (like below) but I would rather prefer an > explicit dma_inherit() call by drivers creating such devices. > > diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h > index ba437f090a74..ea6fb9b0e8fa 100644 > --- a/arch/arm64/include/asm/dma-mapping.h > +++ b/arch/arm64/include/asm/dma-mapping.h > @@ -29,8 +29,11 @@ extern struct dma_map_ops dummy_dma_ops; > > static inline struct dma_map_ops *__generic_dma_ops(struct device *dev) > { > - if (dev && dev->archdata.dma_ops) > - return dev->archdata.dma_ops; > + while (dev) { > + if (dev->archdata.dma_ops) > + return dev->archdata.dma_ops; > + dev = dev->parent; > + } I think this would be a very bad idea: we don't want to have random devices be able to perform DMA just because their parent devices have been set up that way. Arnd