Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758455Ab3J2R0E (ORCPT ); Tue, 29 Oct 2013 13:26:04 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:21446 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757888Ab3J2R0C (ORCPT ); Tue, 29 Oct 2013 13:26:02 -0400 X-IronPort-AV: E=Sophos;i="4.93,594,1378857600"; d="scan'208";a="65923201" Date: Tue, 29 Oct 2013 17:24:50 +0000 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Russell King - ARM Linux CC: Konrad Rzeszutek Wilk , Stefano Stabellini , , , , , Subject: Re: [PATCH v9 01/18] arm: make SWIOTLB available In-Reply-To: <20131029142626.GQ16735@n2100.arm.linux.org.uk> Message-ID: References: <1382698313-13161-1-git-send-email-stefano.stabellini@eu.citrix.com> <20131029142023.GE20487@phenom.dumpdata.com> <20131029142626.GQ16735@n2100.arm.linux.org.uk> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5141 Lines: 147 On Tue, 29 Oct 2013, Russell King - ARM Linux wrote: > On Tue, Oct 29, 2013 at 10:20:23AM -0400, Konrad Rzeszutek Wilk wrote: > > On Tue, Oct 29, 2013 at 04:41:40AM +0000, Stefano Stabellini wrote: > > > ping? > > > > You know you are pinging yourself, right ? :-) > > And the patch was only Cc'd. I'm starting to read stuff which isn't > flagged as having me in the To: line with less priority in recent times. good to know > > > On Fri, 25 Oct 2013, Stefano Stabellini wrote: > > > > Russell, > > > > this is the only patch that needs an ack at the moment. > > > > As you commented on it before and I have already addressed your comments > > > > few versions ago, unless you have any complaints I am going to add it to > > > > linux-next and I am thinking of merging it during the next merge window. > > > > > > > > On Fri, 25 Oct 2013, Stefano Stabellini wrote: > > > > > IOMMU_HELPER is needed because SWIOTLB calls iommu_is_span_boundary, > > > > > provided by lib/iommu_helper.c. > > > > > > > > > > Signed-off-by: Stefano Stabellini > > > > > Reviewed-by: Konrad Rzeszutek Wilk > > > > > CC: will.deacon@arm.com > > > > > CC: linux@arm.linux.org.uk > > > > > > > > > > > > > > > Changes in v8: > > > > > - use __phys_to_pfn and __pfn_to_phys. > > > > > > > > > > Changes in v7: > > > > > - dma_mark_clean: empty implementation; > > > > > - in dma_capable use coherent_dma_mask if dma_mask hasn't been > > > > > allocated. > > > > > > > > > > Changes in v6: > > > > > - check for dev->dma_mask being NULL in dma_capable. > > > > > > > > > > Changes in v5: > > > > > - implement dma_mark_clean using dmac_flush_range. > > > > > > > > > > Changes in v3: > > > > > - dma_capable: do not treat dma_mask as a limit; > > > > > - remove SWIOTLB dependency on NEED_SG_DMA_LENGTH. > > > > > --- > > > > > arch/arm/Kconfig | 6 +++++ > > > > > arch/arm/include/asm/dma-mapping.h | 37 ++++++++++++++++++++++++++++++++++++ > > > > > 2 files changed, 43 insertions(+), 0 deletions(-) > > > > > > > > > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > > > > > index 1ad6fb6..b08374f 100644 > > > > > --- a/arch/arm/Kconfig > > > > > +++ b/arch/arm/Kconfig > > > > > @@ -1872,6 +1872,12 @@ config CC_STACKPROTECTOR > > > > > neutralized via a kernel panic. > > > > > This feature requires gcc version 4.2 or above. > > > > > > > > > > +config SWIOTLB > > > > > + def_bool y > > > > > + > > > > > +config IOMMU_HELPER > > > > > + def_bool SWIOTLB > > > > > + > > > > > config XEN_DOM0 > > > > > def_bool y > > > > > depends on XEN > > > > > diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h > > > > > index 5b579b9..01b5a3d 100644 > > > > > --- a/arch/arm/include/asm/dma-mapping.h > > > > > +++ b/arch/arm/include/asm/dma-mapping.h > > > > > @@ -10,6 +10,7 @@ > > > > > > > > > > #include > > > > > #include > > > > > +#include > > Why does this need to be here? Your'e not adding anything which > needs it. Legacy of a previous iteration of the patch. I'll remove it. > > > > > +static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr) > > > > > +{ > > > > > + unsigned int offset = paddr & ~PAGE_MASK; > > > > > + return pfn_to_dma(dev, __phys_to_pfn(paddr)) + offset; > > > > > +} > > > > > + > > > > > +static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr) > > > > > +{ > > > > > + unsigned int offset = dev_addr & ~PAGE_MASK; > > > > > + return __pfn_to_phys(dma_to_pfn(dev, dev_addr)) + offset; > > > > > +} > > These look fine. > > > > > > +static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size) > > > > > +{ > > > > > + u64 limit, mask; > > > > > + > > > > > + if (dev->dma_mask) > > > > > + mask = *dev->dma_mask; > > > > > + else > > > > > + mask = dev->coherent_dma_mask; > > This looks like a hack. Either we want to use the streaming mask or > the coherent mask as appropriate for the caller. That should be a choice > the caller makes, not the implementation of this behind the callers back. How should I choose? Admittedly this is a workaround because some drivers (including Calxeda xgmac) don't set the dma_mask when they should: http://marc.info/?l=linux-arm-kernel&m=138082570519601&w=2 I am happy to reduce this to: if (dev->dma_mask) mask = *dev->dma_mask; even though it means that xgmac & co won't be dma_capable. > > > > > + > > > > > + if (mask == 0) > > > > > + return 0; > > > > > + > > > > > + limit = (mask + 1) & ~mask; > > > > > + if (limit && size > limit) > > > > > + return 0; > > > > > + > > > > > + if ((addr | (addr + size - 1)) & ~mask) > > > > > + return 0; > > > > > + > > > > > + return 1; > > > > > +} > > The remainder looks fine to me. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/