Hi Marek, On Wed, Nov 19, 2014 at 11:21:26AM +0000, Marek Szyprowski wrote: > On 2014-11-14 19:56, Will Deacon wrote: > > Hello everybody, > > > > Here is the fourth iteration of the RFC I've previously posted here: > > > > RFCv1: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/283023.html > > RFCv2: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/283752.html > > RFCv3: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/287031.html > > > > Changes since RFCv3 include: > > > > - Drastic simplification of the data structures, so that we no longer > > pass around lists of domains. Instead, dma-mapping is expected to > > allocate the domain (Joerg talked about adding a get_default_domain > > operation to iommu_ops). > > > > - iommu_ops is used to hold the per-instance IOMMU data > > > > - Configuration of DMA segments added to of_dma_configure > > > > All feedback welcome. > > I've rebased my Exynos SYSMMU patches on top of this patchset and it > works fine, > You can find them in the "[PATCH v3 00/19] Exynos SYSMMU (IOMMU) > integration with DT > and DMA-mapping subsystem" thread.
I just saw that and it looks great, thanks! FWIW, I'll take the first 3 patches you have into my series in some shape or another. > You can add to all your patches: > Acked-by: Marek Szyprowski <m.szyprow...@samsung.com> Cheers. > I'm also interested in adding get_default_domain() callback, but I > assume that this > can be done once the basic patchset get merged. Do you plan to work on > it, do you want > me to implement it? If Joerg isn't working on it already (I don't think he is), then please do have a go if you have time. You'll probably want to avoid adding devices with addressing restrictions (i.e. non-zero dma_pfn_offset, weird dma masks) to the default domain, otherwise you'll run into issues initialising the iova allocator. I had a go at getting ARM dma-mapping to use a hypothetical get_default_domain function, so I've included the diff I ended up with below, in case it's at all useful. Will --->8 diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index f3c0d953f6a2..5071553bf6b8 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -121,14 +121,9 @@ static inline unsigned long dma_max_pfn(struct device *dev) } #define dma_max_pfn(dev) dma_max_pfn(dev) -static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base, - u64 size, struct iommu_ops *iommu, - bool coherent) -{ - if (coherent) - set_dma_ops(dev, &arm_coherent_dma_ops); -} #define arch_setup_dma_ops arch_setup_dma_ops +extern void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, + struct iommu_ops *iommu, bool coherent); static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr) { diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index c245d903927f..da2c2667bbb1 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1849,7 +1849,8 @@ struct dma_map_ops iommu_coherent_ops = { * arm_iommu_attach_device function. */ struct dma_iommu_mapping * -arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size) +__arm_iommu_create_mapping(struct iommu_domain *domain, dma_addr_t base, + size_t size) { unsigned int bits = size >> PAGE_SHIFT; unsigned int bitmap_size = BITS_TO_LONGS(bits) * sizeof(long); @@ -1883,17 +1884,12 @@ arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size) mapping->extensions = extensions; mapping->base = base; mapping->bits = BITS_PER_BYTE * bitmap_size; + mapping->domain = domain; spin_lock_init(&mapping->lock); - mapping->domain = iommu_domain_alloc(bus); - if (!mapping->domain) - goto err4; - kref_init(&mapping->kref); return mapping; -err4: - kfree(mapping->bitmaps[0]); err3: kfree(mapping->bitmaps); err2: @@ -1901,6 +1897,23 @@ err2: err: return ERR_PTR(err); } + +struct dma_iommu_mapping * +arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size) +{ + struct dma_iommu_mapping *mapping; + struct iommu_domain *domain; + + domain = iommu_domain_alloc(bus); + if (!domain) + return ERR_PTR(-ENOMEM); + + mapping = __arm_iommu_create_mapping(domain, base, size); + if (IS_ERR(mapping)) + iommu_domain_free(domain); + + return mapping; +} EXPORT_SYMBOL_GPL(arm_iommu_create_mapping); static void release_iommu_mapping(struct kref *kref) @@ -1948,9 +1961,8 @@ EXPORT_SYMBOL_GPL(arm_iommu_release_mapping); * arm_iommu_create_mapping) * * Attaches specified io address space mapping to the provided device, - * this replaces the dma operations (dma_map_ops pointer) with the - * IOMMU aware version. More than one client might be attached to - * the same io address space mapping. + * More than one client might be attached to the same io address space + * mapping. */ int arm_iommu_attach_device(struct device *dev, struct dma_iommu_mapping *mapping) @@ -1963,7 +1975,6 @@ int arm_iommu_attach_device(struct device *dev, kref_get(&mapping->kref); dev->archdata.mapping = mapping; - set_dma_ops(dev, &iommu_ops); pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev)); return 0; @@ -1975,7 +1986,6 @@ EXPORT_SYMBOL_GPL(arm_iommu_attach_device); * @dev: valid struct device pointer * * Detaches the provided device from a previously attached map. - * This voids the dma operations (dma_map_ops pointer) */ void arm_iommu_detach_device(struct device *dev) { @@ -1990,10 +2000,141 @@ void arm_iommu_detach_device(struct device *dev) iommu_detach_device(mapping->domain, dev); kref_put(&mapping->kref, release_iommu_mapping); dev->archdata.mapping = NULL; - set_dma_ops(dev, NULL); pr_debug("Detached IOMMU controller from %s device.\n", dev_name(dev)); } EXPORT_SYMBOL_GPL(arm_iommu_detach_device); -#endif +static struct dma_map_ops *arm_get_iommu_dma_map_ops(bool coherent) +{ + return coherent ? &iommu_coherent_ops : &iommu_ops; +} + +struct dma_iommu_mapping_entry { + struct list_head list; + struct dma_iommu_mapping *mapping; + struct iommu_domain *domain; + u64 dma_base; + u64 size; + struct kref kref; +}; + +static DEFINE_SPINLOCK(dma_iommu_mapping_lock); +static LIST_HEAD(dma_iommu_mapping_table); + +static void __remove_iommu_mapping_entry(struct kref *kref) +{ + struct dma_iommu_mapping_entry *entry; + + entry = container_of(kref, struct dma_iommu_mapping_entry, kref); + list_del(&entry->list); +} + +static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size, + struct iommu_ops *iommu) +{ + struct iommu_domain *domain; + struct dma_iommu_mapping_entry *entry = NULL; + + if (!iommu->get_default_domain) + return false; + + domain = iommu->get_default_domain(dev); + if (!domain) + return false; + + spin_lock(&dma_iommu_mapping_lock); + + list_for_each_entry(entry, &dma_iommu_mapping_table, list) { + if (entry->domain == domain) + break; + } + + /* Load entry->mapping after entry -- not strictly necessary for ARM */ + smp_read_barrier_depends(); + + if (!entry) { + struct dma_iommu_mapping *mapping; + + entry = kzalloc(sizeof(*entry), GFP_ATOMIC); + if (!entry) + goto err_unlock; + + entry->domain = domain; + entry->dma_base = dma_base; + entry->size = size; + kref_init(&entry->kref); + list_add(&entry->list, &dma_iommu_mapping_table); + spin_unlock(&dma_iommu_mapping_lock); + + mapping = __arm_iommu_create_mapping(domain, dma_base, size); + if (!IS_ERR(mapping)) + return false; + + smp_wmb(); + entry->mapping = mapping; + } else if (entry->mapping) { + if (entry->dma_base > dma_base || entry->size > size) + goto err_unlock; + + kref_get(&entry->kref); + spin_unlock(&dma_iommu_mapping_lock); + } else { + /* Racing on the same IOMMU */ + goto err_unlock; + } + + if (arm_iommu_attach_device(dev, entry->mapping)) { + int entry_dead; + + pr_warn("Failed to attached device %s to IOMMU mapping\n", + dev_name(dev)); + spin_lock(&dma_iommu_mapping_lock); + entry_dead = kref_put(&entry->kref, + __remove_iommu_mapping_entry); + spin_unlock(&dma_iommu_mapping_lock); + + if (entry_dead) { + entry->mapping->domain = NULL; + arm_iommu_release_mapping(entry->mapping); + } + + return false; + } + + return true; + +err_unlock: + spin_unlock(&dma_iommu_mapping_lock); + return false; +} + +#else + +static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size, + struct iommu_ops *iommu) +{ + return false; +} + +#define arm_get_iommu_dma_map_ops arm_get_dma_map_ops + +#endif /* CONFIG_ARM_DMA_USE_IOMMU */ + +static struct dma_map_ops *arm_get_dma_map_ops(bool coherent) +{ + return coherent ? &arm_coherent_dma_ops : &arm_dma_ops; +} + +void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, + struct iommu_ops *iommu, bool coherent) +{ + struct dma_map_ops *dma_ops; + + if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu)) + dma_ops = arm_get_iommu_dma_map_ops(coherent); + else + dma_ops = arm_get_dma_map_ops(coherent); + + set_dma_ops(dev, dma_ops); +} _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu