From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [RFC PATCH 2/7] dma-mapping: replace set_arch_dma_coherent_ops with arch_setup_dma_ops Date: Mon, 01 Sep 2014 16:27:30 +0200 Message-ID: <3185781.KdfsMO5OZS@wuerfel> References: <1409327670-3495-1-git-send-email-will.deacon@arm.com> <1409327670-3495-3-git-send-email-will.deacon@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1409327670-3495-3-git-send-email-will.deacon-5wv7dgnIgG8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Cc: jroedel-l3A5Bk7waGM@public.gmane.org, Will Deacon , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org, Varun.Sethi-KZfg59tc24xl57MIdRCFDg@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Friday 29 August 2014 16:54:25 Will Deacon wrote: > set_arch_dma_coherent_ops is called from of_dma_configure in order to > swizzle the architectural dma-mapping functions over to a cache-coherent > implementation. This is currently implemented only for ARM. > > In anticipation of re-using this mechanism for IOMMU-backed dma-mapping > ops too, this patch replaces the function with a broader > arch_setup_dma_ops callback which is also responsible for setting the > DMA mask and offset as well as selecting the correct mapping functions. > > A further advantage of this split is that it nicely isolates the > of-specific code from the dma-mapping code, allowing potential reuse by > other buses (e.g. PCI) in the future. > > Signed-off-by: Will Deacon Looks good, just one tiny comment > --- > arch/arm/include/asm/dma-mapping.h | 20 ++++++++++++++---- > drivers/of/platform.c | 42 ++++++++++---------------------------- > include/linux/dma-mapping.h | 8 +++----- > 3 files changed, 30 insertions(+), 40 deletions(-) > > diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h > index c45b61a4b4a5..936125ef3f3f 100644 > --- a/arch/arm/include/asm/dma-mapping.h > +++ b/arch/arm/include/asm/dma-mapping.h > @@ -121,12 +121,24 @@ static inline unsigned long dma_max_pfn(struct device *dev) > } > #define dma_max_pfn(dev) dma_max_pfn(dev) > > -static inline int set_arch_dma_coherent_ops(struct device *dev) > +static inline void arch_setup_dma_ops(struct device *dev, u64 mask, > + unsigned long offset, bool coherent) > { > - set_dma_ops(dev, &arm_coherent_dma_ops); > - return 0; > + dev->coherent_dma_mask = mask; > + > + /* > + * Set dma_mask to coherent_dma_mask by default if the architecture > + * code has not set it. > + */ > + if (!dev->dma_mask) > + dev->dma_mask = &dev->coherent_dma_mask; > + We are in architecture specific code here, and we know that this architecture has not set up the dev->dma_mask pointer, so we can remove the 'if (!dev->dma_mask)' Arnd