search for: arm_get_dma_map_op

From: Thierry Reding <treding at nvidia.com> Depending on the kernel configuration, early ARM architecture setup code may have attached the GPU to a DMA/IOMMU mapping that transparently uses the IOMMU to back the DMA API. Tegra requires special handling for IOMMU backed buffers (a special bit in the GPU's MMU page tables indicates the memory path to take: via the SMMU or directly to the

...t; index af27f1c22d93..87a0037574e4 100644 > --- a/arch/arm/mm/dma-mapping.c > +++ b/arch/arm/mm/dma-mapping.c > @@ -1151,6 +1151,11 @@ int arm_dma_supported(struct device *dev, u64 mask) > return __dma_supported(dev, mask, false); > } > > +static const struct dma_map_ops *arm_get_dma_map_ops(bool coherent) > +{ > + return coherent ? &arm_coherent_dma_ops : &arm_dma_ops; > +} > + > #ifdef CONFIG_ARM_DMA_USE_IOMMU > > static int __dma_info_to_prot(enum dma_data_direction dir, unsigned long attrs) > @@ -2296,7 +2301,7 @@ void arm_iommu_detach_device(st...

...+#ifdef CONFIG_ARM_DMA_USE_IOMMU > + struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev); > + const struct dma_map_ops *dma_ops; > + > + if (!mapping) > + return; > + > + arm_iommu_release_mapping(mapping); > + arm_iommu_detach_device(dev); > + > + dma_ops = arm_get_dma_map_ops(dev->archdata.dma_coherent); > + set_dma_ops(dev, dma_ops); Why not simply: set_dma_ops(dev, arm_get_dma_map_ops(dev->archdata.dma_coherent));

From: Thierry Reding <treding at nvidia.com> An unfortunate interaction between the 32-bit ARM DMA/IOMMU mapping code and Tegra SMMU driver changes to support IOMMU groups introduced a boot- time regression on Tegra124. This was caught very late because none of the standard configurations that are tested on Tegra enable the ARM DMA/ IOMMU mapping code since it is not needed. The reason for

...lease_mapping(mapping); } +void arch_iommu_detach_device(struct device *dev) +{ + struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev); + const struct dma_map_ops *dma_ops; + + if (!mapping) + return; + + arm_iommu_release_mapping(mapping); + arm_iommu_detach_device(dev); + + dma_ops = arm_get_dma_map_ops(dev->archdata.dma_coherent); + set_dma_ops(dev, dma_ops); +} + #else static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size, @@ -2378,6 +2393,10 @@ static void arm_teardown_iommu_dma_ops(struct device *dev) { } #define arm_get_iommu_dma_map_ops arm_get_dma_map_ops...

...mapping.c b/arch/arm/mm/dma-mapping.c index af27f1c22d93..87a0037574e4 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1151,6 +1151,11 @@ int arm_dma_supported(struct device *dev, u64 mask) return __dma_supported(dev, mask, false); } +static const struct dma_map_ops *arm_get_dma_map_ops(bool coherent) +{ + return coherent ? &arm_coherent_dma_ops : &arm_dma_ops; +} + #ifdef CONFIG_ARM_DMA_USE_IOMMU static int __dma_info_to_prot(enum dma_data_direction dir, unsigned long attrs) @@ -2296,7 +2301,7 @@ void arm_iommu_detach_device(struct device *dev) iommu_detach_device(...

...) arm_iommu_release_mapping(mapping); } -#else - -static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size, - const struct iommu_ops *iommu) -{ - return false; -} - -static void arm_teardown_iommu_dma_ops(struct device *dev) { } - -#define arm_get_iommu_dma_map_ops arm_get_dma_map_ops - -#endif /* CONFIG_ARM_DMA_USE_IOMMU */ - static const struct dma_map_ops *arm_get_dma_map_ops(bool coherent) { return coherent ? &arm_coherent_dma_ops : &arm_dma_ops; @@ -2426,7 +2410,6 @@ void arch_teardown_dma_ops(struct device *dev) void arch_iommu_detach_device(struct device *...

...t dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev); > > + const struct dma_map_ops *dma_ops; > > + > > + if (!mapping) > > + return; > > + > > + arm_iommu_release_mapping(mapping); > > + arm_iommu_detach_device(dev); > > + > > + dma_ops = arm_get_dma_map_ops(dev->archdata.dma_coherent); > > + set_dma_ops(dev, dma_ops); > > Why not simply: > > set_dma_ops(dev, arm_get_dma_map_ops(dev->archdata.dma_coherent)); I had that initially, but it looked cluttered to me, so I split it up. I don't care much either way, so I can rev...

From: Thierry Reding <treding at nvidia.com> Depending on the kernel configuration, early ARM architecture setup code may have attached the GPU to a DMA/IOMMU mapping that transparently uses the IOMMU to back the DMA API. Tegra requires special handling for IOMMU backed buffers (a special bit in the GPU's MMU page tables indicates the memory path to take: via the SMMU or directly to the

...ommu_release_mapping(mapping); Potentially freeing the mapping before you try to operate on it is never the best idea. Plus arm_iommu_detach_device() already releases a reference appropriately anyway, so it's a double-free. > + arm_iommu_detach_device(dev); > + > + set_dma_ops(dev, arm_get_dma_map_ops(dev->archdata.dma_coherent)); > +#endif > +} > +EXPORT_SYMBOL(arm_dma_iommu_detach_device); I really don't see why we need an extra function that essentially just duplicates arm_iommu_detach_device(). The only real difference here is that here you reset the DMA ops more appropri...

...d arch_iommu_detach_device(struct device *dev) +{ +#ifdef CONFIG_ARM_DMA_USE_IOMMU + struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev); + const struct dma_map_ops *dma_ops; + + if (!mapping) + return; + + arm_iommu_release_mapping(mapping); + arm_iommu_detach_device(dev); + + dma_ops = arm_get_dma_map_ops(dev->archdata.dma_coherent); + set_dma_ops(dev, dma_ops); +#endif +} -- 2.17.0

...mmu_dma_ops(dev); } + +void arm_dma_iommu_detach_device(struct device *dev) +{ +#ifdef CONFIG_ARM_DMA_USE_IOMMU + struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev); + + if (!mapping) + return; + + arm_iommu_release_mapping(mapping); + arm_iommu_detach_device(dev); + + set_dma_ops(dev, arm_get_dma_map_ops(dev->archdata.dma_coherent)); +#endif +} +EXPORT_SYMBOL(arm_dma_iommu_detach_device); -- 2.17.0

From: Thierry Reding <treding at nvidia.com> An unfortunate interaction between the 32-bit ARM DMA/IOMMU mapping code and Tegra SMMU driver changes to support IOMMU groups introduced a boot- time regression on Tegra124. This was caught very late because none of the standard configurations that are tested on Tegra enable the ARM DMA/ IOMMU mapping code since it is not needed. The reason for

...e, the arm_iommu_release_mapping() is supposed to drop the final reference which was obtained by arm_iommu_create_mapping(). The mapping shouldn't go away irrespective of the order in which these will be called. > > + arm_iommu_detach_device(dev); > > + > > + set_dma_ops(dev, arm_get_dma_map_ops(dev->archdata.dma_coherent)); > > +#endif > > +} > > +EXPORT_SYMBOL(arm_dma_iommu_detach_device); > > I really don't see why we need an extra function that essentially just > duplicates arm_iommu_detach_device(). The only real difference here is that > here yo...