[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v9 01/18] arm: make SWIOTLB available
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 <stefano.stabellini@xxxxxxxxxxxxx> > > > > > Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > > > > > CC: will.deacon@xxxxxxx > > > > > CC: linux@xxxxxxxxxxxxxxxx > > > > > > > > > > > > > > > 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 <asm-generic/dma-coherent.h> > > > > > #include <asm/memory.h> > > > > > +#include <asm/cacheflush.h> > > 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. > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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