--- zzzz-none-000/linux-3.10.107/arch/arm64/mm/dma-mapping.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/arm64/mm/dma-mapping.c	2021-02-04 17:41:59.000000000 +0000
@@ -17,56 +17,507 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/dma-mapping-fast.h>
 #include <linux/gfp.h>
+#include <linux/acpi.h>
 #include <linux/export.h>
 #include <linux/slab.h>
+#include <linux/genalloc.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma-contiguous.h>
 #include <linux/vmalloc.h>
 #include <linux/swiotlb.h>
 
 #include <asm/cacheflush.h>
 
-struct dma_map_ops *dma_ops;
-EXPORT_SYMBOL(dma_ops);
+static pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot,
+				 bool coherent)
+{
+	if (!coherent || dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs))
+		return pgprot_writecombine(prot);
+	return prot;
+}
+
+static struct gen_pool *atomic_pool;
+
+#define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_256K
+static size_t atomic_pool_size = DEFAULT_DMA_COHERENT_POOL_SIZE;
+
+static int __init early_coherent_pool(char *p)
+{
+	atomic_pool_size = memparse(p, &p);
+	return 0;
+}
+early_param("coherent_pool", early_coherent_pool);
+
+static void *__alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags)
+{
+	unsigned long val;
+	void *ptr = NULL;
+
+	if (!atomic_pool) {
+		WARN(1, "coherent pool not initialised!\n");
+		return NULL;
+	}
+
+	val = gen_pool_alloc(atomic_pool, size);
+	if (val) {
+		phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val);
+
+		*ret_page = phys_to_page(phys);
+		ptr = (void *)val;
+		memset(ptr, 0, size);
+	}
+
+	return ptr;
+}
+
+static bool __in_atomic_pool(void *start, size_t size)
+{
+	return addr_in_gen_pool(atomic_pool, (unsigned long)start, size);
+}
 
-static void *arm64_swiotlb_alloc_coherent(struct device *dev, size_t size,
-					  dma_addr_t *dma_handle, gfp_t flags,
-					  struct dma_attrs *attrs)
+static int __free_from_pool(void *start, size_t size)
 {
-	if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
+	if (!__in_atomic_pool(start, size))
+		return 0;
+
+	gen_pool_free(atomic_pool, (unsigned long)start, size);
+
+	return 1;
+}
+
+static void *__dma_alloc_coherent(struct device *dev, size_t size,
+				  dma_addr_t *dma_handle, gfp_t flags,
+				  struct dma_attrs *attrs)
+{
+	if (dev == NULL) {
+		WARN_ONCE(1, "Use an actual device structure for DMA allocation\n");
+		return NULL;
+	}
+
+	if (IS_ENABLED(CONFIG_ZONE_DMA) &&
 	    dev->coherent_dma_mask <= DMA_BIT_MASK(32))
-		flags |= GFP_DMA32;
-	return swiotlb_alloc_coherent(dev, size, dma_handle, flags);
+		flags |= GFP_DMA;
+	if (dev_get_cma_area(dev) && gfpflags_allow_blocking(flags)) {
+		struct page *page;
+		void *addr;
+
+		page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
+							get_order(size));
+		if (!page)
+			return NULL;
+
+		*dma_handle = phys_to_dma(dev, page_to_phys(page));
+		addr = page_address(page);
+		memset(addr, 0, size);
+		return addr;
+	} else {
+		return swiotlb_alloc_coherent(dev, size, dma_handle, flags);
+	}
+}
+
+static void __dma_free_coherent(struct device *dev, size_t size,
+				void *vaddr, dma_addr_t dma_handle,
+				struct dma_attrs *attrs)
+{
+	bool freed;
+	phys_addr_t paddr = dma_to_phys(dev, dma_handle);
+
+	if (dev == NULL) {
+		WARN_ONCE(1, "Use an actual device structure for DMA allocation\n");
+		return;
+	}
+
+	freed = dma_release_from_contiguous(dev,
+					phys_to_page(paddr),
+					size >> PAGE_SHIFT);
+	if (!freed)
+		swiotlb_free_coherent(dev, size, vaddr, dma_handle);
+}
+
+static void *__dma_alloc(struct device *dev, size_t size,
+			 dma_addr_t *dma_handle, gfp_t flags,
+			 struct dma_attrs *attrs)
+{
+	struct page *page;
+	void *ptr, *coherent_ptr;
+	bool coherent = is_device_dma_coherent(dev);
+	pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, false);
+
+	size = PAGE_ALIGN(size);
+
+	if (!coherent && !gfpflags_allow_blocking(flags)) {
+		struct page *page = NULL;
+		void *addr = __alloc_from_pool(size, &page, flags);
+
+		if (addr)
+			*dma_handle = phys_to_dma(dev, page_to_phys(page));
+
+		return addr;
+	}
+
+	ptr = __dma_alloc_coherent(dev, size, dma_handle, flags, attrs);
+	if (!ptr)
+		goto no_mem;
+
+	/* no need for non-cacheable mapping if coherent */
+	if (coherent)
+		return ptr;
+
+	/* remove any dirty cache lines on the kernel alias */
+	__dma_flush_range(ptr, ptr + size);
+
+	/* create a coherent mapping */
+	page = virt_to_page(ptr);
+	coherent_ptr = dma_common_contiguous_remap(page, size, VM_USERMAP,
+						   prot, NULL);
+	if (!coherent_ptr)
+		goto no_map;
+
+	return coherent_ptr;
+
+no_map:
+	__dma_free_coherent(dev, size, ptr, *dma_handle, attrs);
+no_mem:
+	*dma_handle = DMA_ERROR_CODE;
+	return NULL;
+}
+
+static void __dma_free(struct device *dev, size_t size,
+		       void *vaddr, dma_addr_t dma_handle,
+		       struct dma_attrs *attrs)
+{
+	void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle));
+
+	size = PAGE_ALIGN(size);
+
+	if (!is_device_dma_coherent(dev)) {
+		if (__free_from_pool(vaddr, size))
+			return;
+		vunmap(vaddr);
+	}
+	__dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
+}
+
+static dma_addr_t __swiotlb_map_page(struct device *dev, struct page *page,
+				     unsigned long offset, size_t size,
+				     enum dma_data_direction dir,
+				     struct dma_attrs *attrs)
+{
+	dma_addr_t dev_addr;
+
+	dev_addr = swiotlb_map_page(dev, page, offset, size, dir, attrs);
+	if (!is_device_dma_coherent(dev))
+		__dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
+
+	return dev_addr;
+}
+
+
+static void __swiotlb_unmap_page(struct device *dev, dma_addr_t dev_addr,
+				 size_t size, enum dma_data_direction dir,
+				 struct dma_attrs *attrs)
+{
+	if (!is_device_dma_coherent(dev))
+		__dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
+	swiotlb_unmap_page(dev, dev_addr, size, dir, attrs);
+}
+
+static int __swiotlb_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
+				  int nelems, enum dma_data_direction dir,
+				  struct dma_attrs *attrs)
+{
+	struct scatterlist *sg;
+	int i, ret;
+
+	ret = swiotlb_map_sg_attrs(dev, sgl, nelems, dir, attrs);
+	if (!is_device_dma_coherent(dev))
+		for_each_sg(sgl, sg, ret, i)
+			__dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
+				       sg->length, dir);
+
+	return ret;
+}
+
+static void __swiotlb_unmap_sg_attrs(struct device *dev,
+				     struct scatterlist *sgl, int nelems,
+				     enum dma_data_direction dir,
+				     struct dma_attrs *attrs)
+{
+	struct scatterlist *sg;
+	int i;
+
+	if (!is_device_dma_coherent(dev))
+		for_each_sg(sgl, sg, nelems, i)
+			__dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
+					 sg->length, dir);
+	swiotlb_unmap_sg_attrs(dev, sgl, nelems, dir, attrs);
+}
+
+static void __swiotlb_sync_single_for_cpu(struct device *dev,
+					  dma_addr_t dev_addr, size_t size,
+					  enum dma_data_direction dir)
+{
+	if (!is_device_dma_coherent(dev))
+		__dma_unmap_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
+	swiotlb_sync_single_for_cpu(dev, dev_addr, size, dir);
 }
 
-static void arm64_swiotlb_free_coherent(struct device *dev, size_t size,
-					void *vaddr, dma_addr_t dma_handle,
-					struct dma_attrs *attrs)
-{
-	swiotlb_free_coherent(dev, size, vaddr, dma_handle);
-}
-
-static struct dma_map_ops arm64_swiotlb_dma_ops = {
-	.alloc = arm64_swiotlb_alloc_coherent,
-	.free = arm64_swiotlb_free_coherent,
-	.map_page = swiotlb_map_page,
-	.unmap_page = swiotlb_unmap_page,
-	.map_sg = swiotlb_map_sg_attrs,
-	.unmap_sg = swiotlb_unmap_sg_attrs,
-	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
-	.sync_single_for_device = swiotlb_sync_single_for_device,
-	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
-	.sync_sg_for_device = swiotlb_sync_sg_for_device,
+static void __swiotlb_sync_single_for_device(struct device *dev,
+					     dma_addr_t dev_addr, size_t size,
+					     enum dma_data_direction dir)
+{
+	swiotlb_sync_single_for_device(dev, dev_addr, size, dir);
+	if (!is_device_dma_coherent(dev))
+		__dma_map_area(phys_to_virt(dma_to_phys(dev, dev_addr)), size, dir);
+}
+
+static void __swiotlb_sync_sg_for_cpu(struct device *dev,
+				      struct scatterlist *sgl, int nelems,
+				      enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	if (!is_device_dma_coherent(dev))
+		for_each_sg(sgl, sg, nelems, i)
+			__dma_unmap_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
+					 sg->length, dir);
+	swiotlb_sync_sg_for_cpu(dev, sgl, nelems, dir);
+}
+
+static void __swiotlb_sync_sg_for_device(struct device *dev,
+					 struct scatterlist *sgl, int nelems,
+					 enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	swiotlb_sync_sg_for_device(dev, sgl, nelems, dir);
+	if (!is_device_dma_coherent(dev))
+		for_each_sg(sgl, sg, nelems, i)
+			__dma_map_area(phys_to_virt(dma_to_phys(dev, sg->dma_address)),
+				       sg->length, dir);
+}
+
+static int __swiotlb_mmap(struct device *dev,
+			  struct vm_area_struct *vma,
+			  void *cpu_addr, dma_addr_t dma_addr, size_t size,
+			  struct dma_attrs *attrs)
+{
+	int ret = -ENXIO;
+	unsigned long nr_vma_pages = (vma->vm_end - vma->vm_start) >>
+					PAGE_SHIFT;
+	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned long pfn = dma_to_phys(dev, dma_addr) >> PAGE_SHIFT;
+	unsigned long off = vma->vm_pgoff;
+
+	vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot,
+					     is_device_dma_coherent(dev));
+
+	if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
+		return ret;
+
+	if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {
+		ret = remap_pfn_range(vma, vma->vm_start,
+				      pfn + off,
+				      vma->vm_end - vma->vm_start,
+				      vma->vm_page_prot);
+	}
+
+	return ret;
+}
+
+static int __swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt,
+				 void *cpu_addr, dma_addr_t handle, size_t size,
+				 struct dma_attrs *attrs)
+{
+	int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+
+	if (!ret)
+		sg_set_page(sgt->sgl, phys_to_page(dma_to_phys(dev, handle)),
+			    PAGE_ALIGN(size), 0);
+
+	return ret;
+}
+
+static struct dma_map_ops swiotlb_dma_ops = {
+	.alloc = __dma_alloc,
+	.free = __dma_free,
+	.mmap = __swiotlb_mmap,
+	.get_sgtable = __swiotlb_get_sgtable,
+	.map_page = __swiotlb_map_page,
+	.unmap_page = __swiotlb_unmap_page,
+	.map_sg = __swiotlb_map_sg_attrs,
+	.unmap_sg = __swiotlb_unmap_sg_attrs,
+	.sync_single_for_cpu = __swiotlb_sync_single_for_cpu,
+	.sync_single_for_device = __swiotlb_sync_single_for_device,
+	.sync_sg_for_cpu = __swiotlb_sync_sg_for_cpu,
+	.sync_sg_for_device = __swiotlb_sync_sg_for_device,
 	.dma_supported = swiotlb_dma_supported,
 	.mapping_error = swiotlb_dma_mapping_error,
 };
 
-void __init arm64_swiotlb_init(void)
+static int __init atomic_pool_init(void)
+{
+	pgprot_t prot = __pgprot(PROT_NORMAL_NC);
+	unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT;
+	struct page *page;
+	void *addr;
+	unsigned int pool_size_order = get_order(atomic_pool_size);
+
+	if (dev_get_cma_area(NULL))
+		page = dma_alloc_from_contiguous(NULL, nr_pages,
+							pool_size_order);
+	else
+		page = alloc_pages(GFP_DMA, pool_size_order);
+
+	if (page) {
+		int ret;
+		void *page_addr = page_address(page);
+
+		memset(page_addr, 0, atomic_pool_size);
+		__dma_flush_range(page_addr, page_addr + atomic_pool_size);
+
+		atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
+		if (!atomic_pool)
+			goto free_page;
+
+		addr = dma_common_contiguous_remap(page, atomic_pool_size,
+					VM_USERMAP, prot, atomic_pool_init);
+
+		if (!addr)
+			goto destroy_genpool;
+
+		ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr,
+					page_to_phys(page),
+					atomic_pool_size, -1);
+		if (ret)
+			goto remove_mapping;
+
+		gen_pool_set_algo(atomic_pool,
+				  gen_pool_first_fit_order_align,
+				  (void *)PAGE_SHIFT);
+
+		pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n",
+			atomic_pool_size / 1024);
+		return 0;
+	}
+	goto out;
+
+remove_mapping:
+	dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP);
+destroy_genpool:
+	gen_pool_destroy(atomic_pool);
+	atomic_pool = NULL;
+free_page:
+	if (!dma_release_from_contiguous(NULL, page, nr_pages))
+		__free_pages(page, pool_size_order);
+out:
+	pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
+		atomic_pool_size / 1024);
+	return -ENOMEM;
+}
+
+/********************************************
+ * The following APIs are for dummy DMA ops *
+ ********************************************/
+
+static void *__dummy_alloc(struct device *dev, size_t size,
+			   dma_addr_t *dma_handle, gfp_t flags,
+			   struct dma_attrs *attrs)
+{
+	return NULL;
+}
+
+static void __dummy_free(struct device *dev, size_t size,
+			 void *vaddr, dma_addr_t dma_handle,
+			 struct dma_attrs *attrs)
+{
+}
+
+static int __dummy_mmap(struct device *dev,
+			struct vm_area_struct *vma,
+			void *cpu_addr, dma_addr_t dma_addr, size_t size,
+			struct dma_attrs *attrs)
+{
+	return -ENXIO;
+}
+
+static dma_addr_t __dummy_map_page(struct device *dev, struct page *page,
+				   unsigned long offset, size_t size,
+				   enum dma_data_direction dir,
+				   struct dma_attrs *attrs)
+{
+	return DMA_ERROR_CODE;
+}
+
+static void __dummy_unmap_page(struct device *dev, dma_addr_t dev_addr,
+			       size_t size, enum dma_data_direction dir,
+			       struct dma_attrs *attrs)
 {
-	dma_ops = &arm64_swiotlb_dma_ops;
-	swiotlb_init(1);
 }
 
+static int __dummy_map_sg(struct device *dev, struct scatterlist *sgl,
+			  int nelems, enum dma_data_direction dir,
+			  struct dma_attrs *attrs)
+{
+	return 0;
+}
+
+static void __dummy_unmap_sg(struct device *dev,
+			     struct scatterlist *sgl, int nelems,
+			     enum dma_data_direction dir,
+			     struct dma_attrs *attrs)
+{
+}
+
+static void __dummy_sync_single(struct device *dev,
+				dma_addr_t dev_addr, size_t size,
+				enum dma_data_direction dir)
+{
+}
+
+static void __dummy_sync_sg(struct device *dev,
+			    struct scatterlist *sgl, int nelems,
+			    enum dma_data_direction dir)
+{
+}
+
+static int __dummy_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
+{
+	return 1;
+}
+
+static int __dummy_dma_supported(struct device *hwdev, u64 mask)
+{
+	return 0;
+}
+
+struct dma_map_ops dummy_dma_ops = {
+	.alloc                  = __dummy_alloc,
+	.free                   = __dummy_free,
+	.mmap                   = __dummy_mmap,
+	.map_page               = __dummy_map_page,
+	.unmap_page             = __dummy_unmap_page,
+	.map_sg                 = __dummy_map_sg,
+	.unmap_sg               = __dummy_unmap_sg,
+	.sync_single_for_cpu    = __dummy_sync_single,
+	.sync_single_for_device = __dummy_sync_single,
+	.sync_sg_for_cpu        = __dummy_sync_sg,
+	.sync_sg_for_device     = __dummy_sync_sg,
+	.mapping_error          = __dummy_mapping_error,
+	.dma_supported          = __dummy_dma_supported,
+};
+EXPORT_SYMBOL(dummy_dma_ops);
+
+static int __init arm64_dma_init(void)
+{
+	return atomic_pool_init();
+}
+arch_initcall(arm64_dma_init);
+
 #define PREALLOC_DMA_DEBUG_ENTRIES	4096
 
 static int __init dma_debug_do_init(void)
@@ -75,3 +526,518 @@
 	return 0;
 }
 fs_initcall(dma_debug_do_init);
+
+
+#ifdef CONFIG_IOMMU_DMA
+#include <linux/dma-iommu.h>
+#include <linux/platform_device.h>
+#include <linux/amba/bus.h>
+
+/* Thankfully, all cache ops are by VA so we can ignore phys here */
+static void flush_page(struct device *dev, const void *virt, phys_addr_t phys)
+{
+	__dma_flush_range(virt, virt + PAGE_SIZE);
+}
+
+static void *__iommu_alloc_attrs(struct device *dev, size_t size,
+				 dma_addr_t *handle, gfp_t gfp,
+				 struct dma_attrs *attrs)
+{
+	bool coherent = is_device_dma_coherent(dev);
+	int ioprot = dma_direction_to_prot(DMA_BIDIRECTIONAL, coherent);
+	size_t iosize = size;
+	void *addr;
+
+	if (WARN(!dev, "cannot create IOMMU mapping for unknown device\n"))
+		return NULL;
+
+	size = PAGE_ALIGN(size);
+
+	/*
+	 * Some drivers rely on this, and we probably don't want the
+	 * possibility of stale kernel data being read by devices anyway.
+	 */
+	gfp |= __GFP_ZERO;
+
+	if (gfpflags_allow_blocking(gfp)) {
+		struct page **pages;
+		pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, coherent);
+
+		pages = iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
+					handle, flush_page);
+		if (!pages)
+			return NULL;
+
+		addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
+					      __builtin_return_address(0));
+		if (!addr)
+			iommu_dma_free(dev, pages, iosize, handle);
+	} else {
+		struct page *page;
+		/*
+		 * In atomic context we can't remap anything, so we'll only
+		 * get the virtually contiguous buffer we need by way of a
+		 * physically contiguous allocation.
+		 */
+		if (coherent) {
+			page = alloc_pages(gfp, get_order(size));
+			addr = page ? page_address(page) : NULL;
+		} else {
+			addr = __alloc_from_pool(size, &page, gfp);
+		}
+		if (!addr)
+			return NULL;
+
+		*handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
+		if (iommu_dma_mapping_error(dev, *handle)) {
+			if (coherent)
+				__free_pages(page, get_order(size));
+			else
+				__free_from_pool(addr, size);
+			addr = NULL;
+		}
+	}
+	return addr;
+}
+
+static void __iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
+			       dma_addr_t handle, struct dma_attrs *attrs)
+{
+	size_t iosize = size;
+
+	size = PAGE_ALIGN(size);
+	/*
+	 * @cpu_addr will be one of 3 things depending on how it was allocated:
+	 * - A remapped array of pages from iommu_dma_alloc(), for all
+	 *   non-atomic allocations.
+	 * - A non-cacheable alias from the atomic pool, for atomic
+	 *   allocations by non-coherent devices.
+	 * - A normal lowmem address, for atomic allocations by
+	 *   coherent devices.
+	 * Hence how dodgy the below logic looks...
+	 */
+	if (__in_atomic_pool(cpu_addr, size)) {
+		iommu_dma_unmap_page(dev, handle, iosize, 0, NULL);
+		__free_from_pool(cpu_addr, size);
+	} else if (is_vmalloc_addr(cpu_addr)){
+		struct vm_struct *area = find_vm_area(cpu_addr);
+
+		if (WARN_ON(!area || !area->pages))
+			return;
+		iommu_dma_free(dev, area->pages, iosize, &handle);
+		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
+	} else {
+		iommu_dma_unmap_page(dev, handle, iosize, 0, NULL);
+		__free_pages(virt_to_page(cpu_addr), get_order(size));
+	}
+}
+
+static int __iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
+			      void *cpu_addr, dma_addr_t dma_addr, size_t size,
+			      struct dma_attrs *attrs)
+{
+	struct vm_struct *area;
+	int ret;
+
+	vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot,
+					     is_device_dma_coherent(dev));
+
+	if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
+		return ret;
+
+	area = find_vm_area(cpu_addr);
+	if (WARN_ON(!area || !area->pages))
+		return -ENXIO;
+
+	return iommu_dma_mmap(area->pages, size, vma);
+}
+
+static int __iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
+			       void *cpu_addr, dma_addr_t dma_addr,
+			       size_t size, struct dma_attrs *attrs)
+{
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	struct vm_struct *area = find_vm_area(cpu_addr);
+
+	if (WARN_ON(!area || !area->pages))
+		return -ENXIO;
+
+	return sg_alloc_table_from_pages(sgt, area->pages, count, 0, size,
+					 GFP_KERNEL);
+}
+
+static void __iommu_sync_single_for_cpu(struct device *dev,
+					dma_addr_t dev_addr, size_t size,
+					enum dma_data_direction dir)
+{
+	phys_addr_t phys;
+
+	if (is_device_dma_coherent(dev))
+		return;
+
+	phys = iommu_iova_to_phys(iommu_get_domain_for_dev(dev), dev_addr);
+	__dma_unmap_area(phys_to_virt(phys), size, dir);
+}
+
+static void __iommu_sync_single_for_device(struct device *dev,
+					   dma_addr_t dev_addr, size_t size,
+					   enum dma_data_direction dir)
+{
+	phys_addr_t phys;
+
+	if (is_device_dma_coherent(dev))
+		return;
+
+	phys = iommu_iova_to_phys(iommu_get_domain_for_dev(dev), dev_addr);
+	__dma_map_area(phys_to_virt(phys), size, dir);
+}
+
+static dma_addr_t __iommu_map_page(struct device *dev, struct page *page,
+				   unsigned long offset, size_t size,
+				   enum dma_data_direction dir,
+				   struct dma_attrs *attrs)
+{
+	bool coherent = is_device_dma_coherent(dev);
+	int prot = dma_direction_to_prot(dir, coherent);
+	dma_addr_t dev_addr = iommu_dma_map_page(dev, page, offset, size, prot);
+
+	if (!iommu_dma_mapping_error(dev, dev_addr) &&
+	    !dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+		__iommu_sync_single_for_device(dev, dev_addr, size, dir);
+
+	return dev_addr;
+}
+
+static void __iommu_unmap_page(struct device *dev, dma_addr_t dev_addr,
+			       size_t size, enum dma_data_direction dir,
+			       struct dma_attrs *attrs)
+{
+	if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+		__iommu_sync_single_for_cpu(dev, dev_addr, size, dir);
+
+	iommu_dma_unmap_page(dev, dev_addr, size, dir, attrs);
+}
+
+static void __iommu_sync_sg_for_cpu(struct device *dev,
+				    struct scatterlist *sgl, int nelems,
+				    enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	if (is_device_dma_coherent(dev))
+		return;
+
+	for_each_sg(sgl, sg, nelems, i)
+		__dma_unmap_area(sg_virt(sg), sg->length, dir);
+}
+
+static void __iommu_sync_sg_for_device(struct device *dev,
+				       struct scatterlist *sgl, int nelems,
+				       enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	if (is_device_dma_coherent(dev))
+		return;
+
+	for_each_sg(sgl, sg, nelems, i)
+		__dma_map_area(sg_virt(sg), sg->length, dir);
+}
+
+static int __iommu_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
+				int nelems, enum dma_data_direction dir,
+				struct dma_attrs *attrs)
+{
+	bool coherent = is_device_dma_coherent(dev);
+
+	if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+		__iommu_sync_sg_for_device(dev, sgl, nelems, dir);
+
+	return iommu_dma_map_sg(dev, sgl, nelems,
+			dma_direction_to_prot(dir, coherent));
+}
+
+static void __iommu_unmap_sg_attrs(struct device *dev,
+				   struct scatterlist *sgl, int nelems,
+				   enum dma_data_direction dir,
+				   struct dma_attrs *attrs)
+{
+	if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+		__iommu_sync_sg_for_cpu(dev, sgl, nelems, dir);
+
+	iommu_dma_unmap_sg(dev, sgl, nelems, dir, attrs);
+}
+
+static struct dma_map_ops iommu_dma_ops = {
+	.alloc = __iommu_alloc_attrs,
+	.free = __iommu_free_attrs,
+	.mmap = __iommu_mmap_attrs,
+	.get_sgtable = __iommu_get_sgtable,
+	.map_page = __iommu_map_page,
+	.unmap_page = __iommu_unmap_page,
+	.map_sg = __iommu_map_sg_attrs,
+	.unmap_sg = __iommu_unmap_sg_attrs,
+	.sync_single_for_cpu = __iommu_sync_single_for_cpu,
+	.sync_single_for_device = __iommu_sync_single_for_device,
+	.sync_sg_for_cpu = __iommu_sync_sg_for_cpu,
+	.sync_sg_for_device = __iommu_sync_sg_for_device,
+	.dma_supported = iommu_dma_supported,
+	.mapping_error = iommu_dma_mapping_error,
+};
+
+/*
+ * TODO: Right now __iommu_setup_dma_ops() gets called too early to do
+ * everything it needs to - the device is only partially created and the
+ * IOMMU driver hasn't seen it yet, so it can't have a group. Thus we
+ * need this delayed attachment dance. Once IOMMU probe ordering is sorted
+ * to move the arch_setup_dma_ops() call later, all the notifier bits below
+ * become unnecessary, and will go away.
+ */
+struct iommu_dma_notifier_data {
+	struct list_head list;
+	struct device *dev;
+	const struct iommu_ops *ops;
+	u64 dma_base;
+	u64 size;
+};
+static LIST_HEAD(iommu_dma_masters);
+static DEFINE_MUTEX(iommu_dma_notifier_lock);
+
+/* fast mapping is always true for now */
+static bool fast = true;
+
+/*
+ * Temporarily "borrow" a domain feature flag to to tell if we had to resort
+ * to creating our own domain here, in case we need to clean it up again.
+ */
+#define __IOMMU_DOMAIN_FAKE_DEFAULT		(1U << 31)
+
+static void release_iommu_mapping(struct kref *kref)
+{
+	struct dma_iommu_mapping *mapping =
+		container_of(kref, struct dma_iommu_mapping, kref);
+
+	kfree(mapping);
+}
+
+static bool do_iommu_attach(struct device *dev, const struct iommu_ops *ops,
+			   u64 dma_base, u64 size)
+{
+	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+	struct dma_iommu_mapping *mapping;
+	unsigned int bits = size >> PAGE_SHIFT;
+	unsigned int bitmap_size = BITS_TO_LONGS(bits) * sizeof(long);
+	int ret = 0;
+
+	/*
+	 * Best case: The device is either part of a group which was
+	 * already attached to a domain in a previous call, or it's
+	 * been put in a default DMA domain by the IOMMU core.
+	 */
+	if (!domain) {
+		/*
+		 * Urgh. The IOMMU core isn't going to do default domains
+		 * for non-PCI devices anyway, until it has some means of
+		 * abstracting the entirely implementation-specific
+		 * sideband data/SoC topology/unicorn dust that may or
+		 * may not differentiate upstream masters.
+		 * So until then, HORRIBLE HACKS!
+		 */
+		domain = ops->domain_alloc(IOMMU_DOMAIN_DMA);
+		if (!domain)
+			goto out_no_domain;
+
+		domain->ops = ops;
+		domain->type = IOMMU_DOMAIN_DMA | __IOMMU_DOMAIN_FAKE_DEFAULT;
+
+		if (iommu_attach_device(domain, dev))
+			goto out_put_domain;
+	}
+
+	if (fast && !domain->handler_token) {
+		/* Detach the one to arm-smmu and attach to fast-smmu */
+		iommu_detach_device(domain, dev);
+		mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
+		kref_init(&mapping->kref);
+		mapping->base = dma_base;
+		mapping->bits = BITS_PER_BYTE * bitmap_size;
+		mapping->domain = domain;
+
+		ret = fast_smmu_attach_device(dev, mapping);
+		if (ret)
+			goto out_put_domain;
+		if (iommu_dma_init_domain(domain, dma_base, size))
+			goto out_detach;
+
+		dev->archdata.dma_ops = &fast_smmu_dma_ops;
+	} else if (domain->handler_token) {
+
+		dev->archdata.dma_ops = &fast_smmu_dma_ops;
+		dev->archdata.mapping = domain->handler_token;
+		mapping = domain->handler_token;
+		kref_get(&mapping->kref);
+
+	} else {
+		if (iommu_dma_init_domain(domain, dma_base, size))
+			goto out_detach;
+
+		dev->archdata.dma_ops = &fast_smmu_dma_ops;
+	}
+
+	return ret;
+
+out_detach:
+	iommu_detach_device(domain, dev);
+out_put_domain:
+	if (domain->type & __IOMMU_DOMAIN_FAKE_DEFAULT)
+		iommu_domain_free(domain);
+out_no_domain:
+	pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
+		dev_name(dev));
+	return false;
+}
+
+static void queue_iommu_attach(struct device *dev, const struct iommu_ops *ops,
+			      u64 dma_base, u64 size)
+{
+	struct iommu_dma_notifier_data *iommudata;
+
+	iommudata = kzalloc(sizeof(*iommudata), GFP_KERNEL);
+	if (!iommudata)
+		return;
+
+	iommudata->dev = dev;
+	iommudata->ops = ops;
+	iommudata->dma_base = dma_base;
+	iommudata->size = size;
+
+	mutex_lock(&iommu_dma_notifier_lock);
+	list_add(&iommudata->list, &iommu_dma_masters);
+	mutex_unlock(&iommu_dma_notifier_lock);
+}
+
+static int __iommu_attach_notifier(struct notifier_block *nb,
+				   unsigned long action, void *data)
+{
+	struct iommu_dma_notifier_data *master, *tmp;
+
+	if (action != BUS_NOTIFY_ADD_DEVICE)
+		return 0;
+
+	mutex_lock(&iommu_dma_notifier_lock);
+	list_for_each_entry_safe(master, tmp, &iommu_dma_masters, list) {
+		if (do_iommu_attach(master->dev, master->ops,
+				master->dma_base, master->size)) {
+			list_del(&master->list);
+			kfree(master);
+		}
+	}
+	mutex_unlock(&iommu_dma_notifier_lock);
+	return 0;
+}
+
+static int register_iommu_dma_ops_notifier(struct bus_type *bus)
+{
+	struct notifier_block *nb = kzalloc(sizeof(*nb), GFP_KERNEL);
+	int ret;
+
+	if (!nb)
+		return -ENOMEM;
+	/*
+	 * The device must be attached to a domain before the driver probe
+	 * routine gets a chance to start allocating DMA buffers. However,
+	 * the IOMMU driver also needs a chance to configure the iommu_group
+	 * via its add_device callback first, so we need to make the attach
+	 * happen between those two points. Since the IOMMU core uses a bus
+	 * notifier with default priority for add_device, do the same but
+	 * with a lower priority to ensure the appropriate ordering.
+	 */
+	nb->notifier_call = __iommu_attach_notifier;
+	nb->priority = -100;
+
+	ret = bus_register_notifier(bus, nb);
+	if (ret) {
+		pr_warn("Failed to register DMA domain notifier; IOMMU DMA ops unavailable on bus '%s'\n",
+			bus->name);
+		kfree(nb);
+	}
+	return ret;
+}
+
+static int __init __iommu_dma_init(void)
+{
+	int ret;
+
+	ret = iommu_dma_init();
+	if (!ret)
+		ret = register_iommu_dma_ops_notifier(&platform_bus_type);
+	if (!ret)
+		ret = register_iommu_dma_ops_notifier(&amba_bustype);
+
+	/* handle devices queued before this arch_initcall */
+	if (!ret)
+		__iommu_attach_notifier(NULL, BUS_NOTIFY_ADD_DEVICE, NULL);
+	return ret;
+}
+arch_initcall(__iommu_dma_init);
+
+static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+				  const struct iommu_ops *ops)
+{
+	struct iommu_group *group;
+
+	if (!ops)
+		return;
+	/*
+	 * TODO: As a concession to the future, we're ready to handle being
+	 * called both early and late (i.e. after bus_add_device). Once all
+	 * the platform bus code is reworked to call us late and the notifier
+	 * junk above goes away, move the body of do_iommu_attach here.
+	 */
+	group = iommu_group_get(dev);
+	if (group) {
+		do_iommu_attach(dev, ops, dma_base, size);
+		iommu_group_put(group);
+	} else {
+		queue_iommu_attach(dev, ops, dma_base, size);
+	}
+}
+
+void arch_teardown_dma_ops(struct device *dev)
+{
+	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+	struct dma_iommu_mapping *mapping;
+
+	if (domain) {
+		iommu_detach_device(domain, dev);
+		if (domain->type & __IOMMU_DOMAIN_FAKE_DEFAULT)
+			iommu_domain_free(domain);
+	}
+
+	dev->archdata.dma_ops = NULL;
+	mapping = dev->archdata.mapping;
+
+	if (mapping)
+		kref_put(&mapping->kref, release_iommu_mapping);
+}
+
+#else
+
+static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+				  const struct iommu_ops *iommu)
+{ }
+
+#endif  /* CONFIG_IOMMU_DMA */
+
+void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+			const struct iommu_ops *iommu, bool coherent)
+{
+	if (!dev->archdata.dma_ops)
+		dev->archdata.dma_ops = &swiotlb_dma_ops;
+
+	dev->archdata.dma_coherent = coherent;
+	__iommu_setup_dma_ops(dev, dma_base, size, iommu);
+}
+EXPORT_SYMBOL(arch_setup_dma_ops);