Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1832 insertions, 0 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
new file mode 100644
index 000000000..d7909091c
--- /dev/null
+++ b/arch/arm/mm/dma-mapping.c
@@ -0,0 +1,1832 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/arch/arm/mm/dma-mapping.c
+ *
+ *  Copyright (C) 2000-2004 Russell King
+ *
+ *  DMA uncached mapping support.
+ */
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/genalloc.h>
+#include <linux/gfp.h>
+#include <linux/errno.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/dma-direct.h>
+#include <linux/dma-map-ops.h>
+#include <linux/highmem.h>
+#include <linux/memblock.h>
+#include <linux/slab.h>
+#include <linux/iommu.h>
+#include <linux/io.h>
+#include <linux/vmalloc.h>
+#include <linux/sizes.h>
+#include <linux/cma.h>
+
+#include <asm/memory.h>
+#include <asm/highmem.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/mach/arch.h>
+#include <asm/dma-iommu.h>
+#include <asm/mach/map.h>
+#include <asm/system_info.h>
+#include <asm/xen/xen-ops.h>
+
+#include "dma.h"
+#include "mm.h"
+
+struct arm_dma_alloc_args {
+	struct device *dev;
+	size_t size;
+	gfp_t gfp;
+	pgprot_t prot;
+	const void *caller;
+	bool want_vaddr;
+	int coherent_flag;
+};
+
+struct arm_dma_free_args {
+	struct device *dev;
+	size_t size;
+	void *cpu_addr;
+	struct page *page;
+	bool want_vaddr;
+};
+
+#define NORMAL	    0
+#define COHERENT    1
+
+struct arm_dma_allocator {
+	void *(*alloc)(struct arm_dma_alloc_args *args,
+		       struct page **ret_page);
+	void (*free)(struct arm_dma_free_args *args);
+};
+
+struct arm_dma_buffer {
+	struct list_head list;
+	void *virt;
+	struct arm_dma_allocator *allocator;
+};
+
+static LIST_HEAD(arm_dma_bufs);
+static DEFINE_SPINLOCK(arm_dma_bufs_lock);
+
+static struct arm_dma_buffer *arm_dma_buffer_find(void *virt)
+{
+	struct arm_dma_buffer *buf, *found = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&arm_dma_bufs_lock, flags);
+	list_for_each_entry(buf, &arm_dma_bufs, list) {
+		if (buf->virt == virt) {
+			list_del(&buf->list);
+			found = buf;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&arm_dma_bufs_lock, flags);
+	return found;
+}
+
+/*
+ * The DMA API is built upon the notion of "buffer ownership".  A buffer
+ * is either exclusively owned by the CPU (and therefore may be accessed
+ * by it) or exclusively owned by the DMA device.  These helper functions
+ * represent the transitions between these two ownership states.
+ *
+ * Note, however, that on later ARMs, this notion does not work due to
+ * speculative prefetches.  We model our approach on the assumption that
+ * the CPU does do speculative prefetches, which means we clean caches
+ * before transfers and delay cache invalidation until transfer completion.
+ *
+ */
+
+static void __dma_clear_buffer(struct page *page, size_t size, int coherent_flag)
+{
+	/*
+	 * Ensure that the allocated pages are zeroed, and that any data
+	 * lurking in the kernel direct-mapped region is invalidated.
+	 */
+	if (PageHighMem(page)) {
+		phys_addr_t base = __pfn_to_phys(page_to_pfn(page));
+		phys_addr_t end = base + size;
+		while (size > 0) {
+			void *ptr = kmap_atomic(page);
+			memset(ptr, 0, PAGE_SIZE);
+			if (coherent_flag != COHERENT)
+				dmac_flush_range(ptr, ptr + PAGE_SIZE);
+			kunmap_atomic(ptr);
+			page++;
+			size -= PAGE_SIZE;
+		}
+		if (coherent_flag != COHERENT)
+			outer_flush_range(base, end);
+	} else {
+		void *ptr = page_address(page);
+		memset(ptr, 0, size);
+		if (coherent_flag != COHERENT) {
+			dmac_flush_range(ptr, ptr + size);
+			outer_flush_range(__pa(ptr), __pa(ptr) + size);
+		}
+	}
+}
+
+/*
+ * Allocate a DMA buffer for 'dev' of size 'size' using the
+ * specified gfp mask.  Note that 'size' must be page aligned.
+ */
+static struct page *__dma_alloc_buffer(struct device *dev, size_t size,
+				       gfp_t gfp, int coherent_flag)
+{
+	unsigned long order = get_order(size);
+	struct page *page, *p, *e;
+
+	page = alloc_pages(gfp, order);
+	if (!page)
+		return NULL;
+
+	/*
+	 * Now split the huge page and free the excess pages
+	 */
+	split_page(page, order);
+	for (p = page + (size >> PAGE_SHIFT), e = page + (1 << order); p < e; p++)
+		__free_page(p);
+
+	__dma_clear_buffer(page, size, coherent_flag);
+
+	return page;
+}
+
+/*
+ * Free a DMA buffer.  'size' must be page aligned.
+ */
+static void __dma_free_buffer(struct page *page, size_t size)
+{
+	struct page *e = page + (size >> PAGE_SHIFT);
+
+	while (page < e) {
+		__free_page(page);
+		page++;
+	}
+}
+
+static void *__alloc_from_contiguous(struct device *dev, size_t size,
+				     pgprot_t prot, struct page **ret_page,
+				     const void *caller, bool want_vaddr,
+				     int coherent_flag, gfp_t gfp);
+
+static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
+				 pgprot_t prot, struct page **ret_page,
+				 const void *caller, bool want_vaddr);
+
+#define DEFAULT_DMA_COHERENT_POOL_SIZE	SZ_256K
+static struct gen_pool *atomic_pool __ro_after_init;
+
+static size_t atomic_pool_size __initdata = 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);
+
+/*
+ * Initialise the coherent pool for atomic allocations.
+ */
+static int __init atomic_pool_init(void)
+{
+	pgprot_t prot = pgprot_dmacoherent(PAGE_KERNEL);
+	gfp_t gfp = GFP_KERNEL | GFP_DMA;
+	struct page *page;
+	void *ptr;
+
+	atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
+	if (!atomic_pool)
+		goto out;
+	/*
+	 * The atomic pool is only used for non-coherent allocations
+	 * so we must pass NORMAL for coherent_flag.
+	 */
+	if (dev_get_cma_area(NULL))
+		ptr = __alloc_from_contiguous(NULL, atomic_pool_size, prot,
+				      &page, atomic_pool_init, true, NORMAL,
+				      GFP_KERNEL);
+	else
+		ptr = __alloc_remap_buffer(NULL, atomic_pool_size, gfp, prot,
+					   &page, atomic_pool_init, true);
+	if (ptr) {
+		int ret;
+
+		ret = gen_pool_add_virt(atomic_pool, (unsigned long)ptr,
+					page_to_phys(page),
+					atomic_pool_size, -1);
+		if (ret)
+			goto destroy_genpool;
+
+		gen_pool_set_algo(atomic_pool,
+				gen_pool_first_fit_order_align,
+				NULL);
+		pr_info("DMA: preallocated %zu KiB pool for atomic coherent allocations\n",
+		       atomic_pool_size / 1024);
+		return 0;
+	}
+
+destroy_genpool:
+	gen_pool_destroy(atomic_pool);
+	atomic_pool = NULL;
+out:
+	pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
+	       atomic_pool_size / 1024);
+	return -ENOMEM;
+}
+/*
+ * CMA is activated by core_initcall, so we must be called after it.
+ */
+postcore_initcall(atomic_pool_init);
+
+#ifdef CONFIG_CMA_AREAS
+struct dma_contig_early_reserve {
+	phys_addr_t base;
+	unsigned long size;
+};
+
+static struct dma_contig_early_reserve dma_mmu_remap[MAX_CMA_AREAS] __initdata;
+
+static int dma_mmu_remap_num __initdata;
+
+void __init dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
+{
+	dma_mmu_remap[dma_mmu_remap_num].base = base;
+	dma_mmu_remap[dma_mmu_remap_num].size = size;
+	dma_mmu_remap_num++;
+}
+
+void __init dma_contiguous_remap(void)
+{
+	int i;
+	for (i = 0; i < dma_mmu_remap_num; i++) {
+		phys_addr_t start = dma_mmu_remap[i].base;
+		phys_addr_t end = start + dma_mmu_remap[i].size;
+		struct map_desc map;
+		unsigned long addr;
+
+		if (end > arm_lowmem_limit)
+			end = arm_lowmem_limit;
+		if (start >= end)
+			continue;
+
+		map.pfn = __phys_to_pfn(start);
+		map.virtual = __phys_to_virt(start);
+		map.length = end - start;
+		map.type = MT_MEMORY_DMA_READY;
+
+		/*
+		 * Clear previous low-memory mapping to ensure that the
+		 * TLB does not see any conflicting entries, then flush
+		 * the TLB of the old entries before creating new mappings.
+		 *
+		 * This ensures that any speculatively loaded TLB entries
+		 * (even though they may be rare) can not cause any problems,
+		 * and ensures that this code is architecturally compliant.
+		 */
+		for (addr = __phys_to_virt(start); addr < __phys_to_virt(end);
+		     addr += PMD_SIZE)
+			pmd_clear(pmd_off_k(addr));
+
+		flush_tlb_kernel_range(__phys_to_virt(start),
+				       __phys_to_virt(end));
+
+		iotable_init(&map, 1);
+	}
+}
+#endif
+
+static int __dma_update_pte(pte_t *pte, unsigned long addr, void *data)
+{
+	struct page *page = virt_to_page((void *)addr);
+	pgprot_t prot = *(pgprot_t *)data;
+
+	set_pte_ext(pte, mk_pte(page, prot), 0);
+	return 0;
+}
+
+static void __dma_remap(struct page *page, size_t size, pgprot_t prot)
+{
+	unsigned long start = (unsigned long) page_address(page);
+	unsigned end = start + size;
+
+	apply_to_page_range(&init_mm, start, size, __dma_update_pte, &prot);
+	flush_tlb_kernel_range(start, end);
+}
+
+static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
+				 pgprot_t prot, struct page **ret_page,
+				 const void *caller, bool want_vaddr)
+{
+	struct page *page;
+	void *ptr = NULL;
+	/*
+	 * __alloc_remap_buffer is only called when the device is
+	 * non-coherent
+	 */
+	page = __dma_alloc_buffer(dev, size, gfp, NORMAL);
+	if (!page)
+		return NULL;
+	if (!want_vaddr)
+		goto out;
+
+	ptr = dma_common_contiguous_remap(page, size, prot, caller);
+	if (!ptr) {
+		__dma_free_buffer(page, size);
+		return NULL;
+	}
+
+ out:
+	*ret_page = page;
+	return ptr;
+}
+
+static void *__alloc_from_pool(size_t size, struct page **ret_page)
+{
+	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;
+	}
+
+	return ptr;
+}
+
+static bool __in_atomic_pool(void *start, size_t size)
+{
+	return gen_pool_has_addr(atomic_pool, (unsigned long)start, size);
+}
+
+static int __free_from_pool(void *start, size_t size)
+{
+	if (!__in_atomic_pool(start, size))
+		return 0;
+
+	gen_pool_free(atomic_pool, (unsigned long)start, size);
+
+	return 1;
+}
+
+static void *__alloc_from_contiguous(struct device *dev, size_t size,
+				     pgprot_t prot, struct page **ret_page,
+				     const void *caller, bool want_vaddr,
+				     int coherent_flag, gfp_t gfp)
+{
+	unsigned long order = get_order(size);
+	size_t count = size >> PAGE_SHIFT;
+	struct page *page;
+	void *ptr = NULL;
+
+	page = dma_alloc_from_contiguous(dev, count, order, gfp & __GFP_NOWARN);
+	if (!page)
+		return NULL;
+
+	__dma_clear_buffer(page, size, coherent_flag);
+
+	if (!want_vaddr)
+		goto out;
+
+	if (PageHighMem(page)) {
+		ptr = dma_common_contiguous_remap(page, size, prot, caller);
+		if (!ptr) {
+			dma_release_from_contiguous(dev, page, count);
+			return NULL;
+		}
+	} else {
+		__dma_remap(page, size, prot);
+		ptr = page_address(page);
+	}
+
+ out:
+	*ret_page = page;
+	return ptr;
+}
+
+static void __free_from_contiguous(struct device *dev, struct page *page,
+				   void *cpu_addr, size_t size, bool want_vaddr)
+{
+	if (want_vaddr) {
+		if (PageHighMem(page))
+			dma_common_free_remap(cpu_addr, size);
+		else
+			__dma_remap(page, size, PAGE_KERNEL);
+	}
+	dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
+}
+
+static inline pgprot_t __get_dma_pgprot(unsigned long attrs, pgprot_t prot)
+{
+	prot = (attrs & DMA_ATTR_WRITE_COMBINE) ?
+			pgprot_writecombine(prot) :
+			pgprot_dmacoherent(prot);
+	return prot;
+}
+
+static void *__alloc_simple_buffer(struct device *dev, size_t size, gfp_t gfp,
+				   struct page **ret_page)
+{
+	struct page *page;
+	/* __alloc_simple_buffer is only called when the device is coherent */
+	page = __dma_alloc_buffer(dev, size, gfp, COHERENT);
+	if (!page)
+		return NULL;
+
+	*ret_page = page;
+	return page_address(page);
+}
+
+static void *simple_allocator_alloc(struct arm_dma_alloc_args *args,
+				    struct page **ret_page)
+{
+	return __alloc_simple_buffer(args->dev, args->size, args->gfp,
+				     ret_page);
+}
+
+static void simple_allocator_free(struct arm_dma_free_args *args)
+{
+	__dma_free_buffer(args->page, args->size);
+}
+
+static struct arm_dma_allocator simple_allocator = {
+	.alloc = simple_allocator_alloc,
+	.free = simple_allocator_free,
+};
+
+static void *cma_allocator_alloc(struct arm_dma_alloc_args *args,
+				 struct page **ret_page)
+{
+	return __alloc_from_contiguous(args->dev, args->size, args->prot,
+				       ret_page, args->caller,
+				       args->want_vaddr, args->coherent_flag,
+				       args->gfp);
+}
+
+static void cma_allocator_free(struct arm_dma_free_args *args)
+{
+	__free_from_contiguous(args->dev, args->page, args->cpu_addr,
+			       args->size, args->want_vaddr);
+}
+
+static struct arm_dma_allocator cma_allocator = {
+	.alloc = cma_allocator_alloc,
+	.free = cma_allocator_free,
+};
+
+static void *pool_allocator_alloc(struct arm_dma_alloc_args *args,
+				  struct page **ret_page)
+{
+	return __alloc_from_pool(args->size, ret_page);
+}
+
+static void pool_allocator_free(struct arm_dma_free_args *args)
+{
+	__free_from_pool(args->cpu_addr, args->size);
+}
+
+static struct arm_dma_allocator pool_allocator = {
+	.alloc = pool_allocator_alloc,
+	.free = pool_allocator_free,
+};
+
+static void *remap_allocator_alloc(struct arm_dma_alloc_args *args,
+				   struct page **ret_page)
+{
+	return __alloc_remap_buffer(args->dev, args->size, args->gfp,
+				    args->prot, ret_page, args->caller,
+				    args->want_vaddr);
+}
+
+static void remap_allocator_free(struct arm_dma_free_args *args)
+{
+	if (args->want_vaddr)
+		dma_common_free_remap(args->cpu_addr, args->size);
+
+	__dma_free_buffer(args->page, args->size);
+}
+
+static struct arm_dma_allocator remap_allocator = {
+	.alloc = remap_allocator_alloc,
+	.free = remap_allocator_free,
+};
+
+static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
+			 gfp_t gfp, pgprot_t prot, bool is_coherent,
+			 unsigned long attrs, const void *caller)
+{
+	u64 mask = min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
+	struct page *page = NULL;
+	void *addr;
+	bool allowblock, cma;
+	struct arm_dma_buffer *buf;
+	struct arm_dma_alloc_args args = {
+		.dev = dev,
+		.size = PAGE_ALIGN(size),
+		.gfp = gfp,
+		.prot = prot,
+		.caller = caller,
+		.want_vaddr = ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0),
+		.coherent_flag = is_coherent ? COHERENT : NORMAL,
+	};
+
+#ifdef CONFIG_DMA_API_DEBUG
+	u64 limit = (mask + 1) & ~mask;
+	if (limit && size >= limit) {
+		dev_warn(dev, "coherent allocation too big (requested %#x mask %#llx)\n",
+			size, mask);
+		return NULL;
+	}
+#endif
+
+	buf = kzalloc(sizeof(*buf),
+		      gfp & ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM));
+	if (!buf)
+		return NULL;
+
+	if (mask < 0xffffffffULL)
+		gfp |= GFP_DMA;
+
+	/*
+	 * Following is a work-around (a.k.a. hack) to prevent pages
+	 * with __GFP_COMP being passed to split_page() which cannot
+	 * handle them.  The real problem is that this flag probably
+	 * should be 0 on ARM as it is not supported on this
+	 * platform; see CONFIG_HUGETLBFS.
+	 */
+	gfp &= ~(__GFP_COMP);
+	args.gfp = gfp;
+
+	*handle = DMA_MAPPING_ERROR;
+	allowblock = gfpflags_allow_blocking(gfp);
+	cma = allowblock ? dev_get_cma_area(dev) : NULL;
+
+	if (cma)
+		buf->allocator = &cma_allocator;
+	else if (is_coherent)
+		buf->allocator = &simple_allocator;
+	else if (allowblock)
+		buf->allocator = &remap_allocator;
+	else
+		buf->allocator = &pool_allocator;
+
+	addr = buf->allocator->alloc(&args, &page);
+
+	if (page) {
+		unsigned long flags;
+
+		*handle = phys_to_dma(dev, page_to_phys(page));
+		buf->virt = args.want_vaddr ? addr : page;
+
+		spin_lock_irqsave(&arm_dma_bufs_lock, flags);
+		list_add(&buf->list, &arm_dma_bufs);
+		spin_unlock_irqrestore(&arm_dma_bufs_lock, flags);
+	} else {
+		kfree(buf);
+	}
+
+	return args.want_vaddr ? addr : page;
+}
+
+/*
+ * Free a buffer as defined by the above mapping.
+ */
+static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
+			   dma_addr_t handle, unsigned long attrs,
+			   bool is_coherent)
+{
+	struct page *page = phys_to_page(dma_to_phys(dev, handle));
+	struct arm_dma_buffer *buf;
+	struct arm_dma_free_args args = {
+		.dev = dev,
+		.size = PAGE_ALIGN(size),
+		.cpu_addr = cpu_addr,
+		.page = page,
+		.want_vaddr = ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0),
+	};
+
+	buf = arm_dma_buffer_find(cpu_addr);
+	if (WARN(!buf, "Freeing invalid buffer %p\n", cpu_addr))
+		return;
+
+	buf->allocator->free(&args);
+	kfree(buf);
+}
+
+static void dma_cache_maint_page(struct page *page, unsigned long offset,
+	size_t size, enum dma_data_direction dir,
+	void (*op)(const void *, size_t, int))
+{
+	unsigned long pfn;
+	size_t left = size;
+
+	pfn = page_to_pfn(page) + offset / PAGE_SIZE;
+	offset %= PAGE_SIZE;
+
+	/*
+	 * A single sg entry may refer to multiple physically contiguous
+	 * pages.  But we still need to process highmem pages individually.
+	 * If highmem is not configured then the bulk of this loop gets
+	 * optimized out.
+	 */
+	do {
+		size_t len = left;
+		void *vaddr;
+
+		page = pfn_to_page(pfn);
+
+		if (PageHighMem(page)) {
+			if (len + offset > PAGE_SIZE)
+				len = PAGE_SIZE - offset;
+
+			if (cache_is_vipt_nonaliasing()) {
+				vaddr = kmap_atomic(page);
+				op(vaddr + offset, len, dir);
+				kunmap_atomic(vaddr);
+			} else {
+				vaddr = kmap_high_get(page);
+				if (vaddr) {
+					op(vaddr + offset, len, dir);
+					kunmap_high(page);
+				}
+			}
+		} else {
+			vaddr = page_address(page) + offset;
+			op(vaddr, len, dir);
+		}
+		offset = 0;
+		pfn++;
+		left -= len;
+	} while (left);
+}
+
+/*
+ * Make an area consistent for devices.
+ * Note: Drivers should NOT use this function directly.
+ * Use the driver DMA support - see dma-mapping.h (dma_sync_*)
+ */
+static void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
+	size_t size, enum dma_data_direction dir)
+{
+	phys_addr_t paddr;
+
+	dma_cache_maint_page(page, off, size, dir, dmac_map_area);
+
+	paddr = page_to_phys(page) + off;
+	if (dir == DMA_FROM_DEVICE) {
+		outer_inv_range(paddr, paddr + size);
+	} else {
+		outer_clean_range(paddr, paddr + size);
+	}
+	/* FIXME: non-speculating: flush on bidirectional mappings? */
+}
+
+static void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
+	size_t size, enum dma_data_direction dir)
+{
+	phys_addr_t paddr = page_to_phys(page) + off;
+
+	/* FIXME: non-speculating: not required */
+	/* in any case, don't bother invalidating if DMA to device */
+	if (dir != DMA_TO_DEVICE) {
+		outer_inv_range(paddr, paddr + size);
+
+		dma_cache_maint_page(page, off, size, dir, dmac_unmap_area);
+	}
+
+	/*
+	 * Mark the D-cache clean for these pages to avoid extra flushing.
+	 */
+	if (dir != DMA_TO_DEVICE && size >= PAGE_SIZE) {
+		unsigned long pfn;
+		size_t left = size;
+
+		pfn = page_to_pfn(page) + off / PAGE_SIZE;
+		off %= PAGE_SIZE;
+		if (off) {
+			pfn++;
+			left -= PAGE_SIZE - off;
+		}
+		while (left >= PAGE_SIZE) {
+			page = pfn_to_page(pfn++);
+			set_bit(PG_dcache_clean, &page->flags);
+			left -= PAGE_SIZE;
+		}
+	}
+}
+
+#ifdef CONFIG_ARM_DMA_USE_IOMMU
+
+static int __dma_info_to_prot(enum dma_data_direction dir, unsigned long attrs)
+{
+	int prot = 0;
+
+	if (attrs & DMA_ATTR_PRIVILEGED)
+		prot |= IOMMU_PRIV;
+
+	switch (dir) {
+	case DMA_BIDIRECTIONAL:
+		return prot | IOMMU_READ | IOMMU_WRITE;
+	case DMA_TO_DEVICE:
+		return prot | IOMMU_READ;
+	case DMA_FROM_DEVICE:
+		return prot | IOMMU_WRITE;
+	default:
+		return prot;
+	}
+}
+
+/* IOMMU */
+
+static int extend_iommu_mapping(struct dma_iommu_mapping *mapping);
+
+static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
+				      size_t size)
+{
+	unsigned int order = get_order(size);
+	unsigned int align = 0;
+	unsigned int count, start;
+	size_t mapping_size = mapping->bits << PAGE_SHIFT;
+	unsigned long flags;
+	dma_addr_t iova;
+	int i;
+
+	if (order > CONFIG_ARM_DMA_IOMMU_ALIGNMENT)
+		order = CONFIG_ARM_DMA_IOMMU_ALIGNMENT;
+
+	count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	align = (1 << order) - 1;
+
+	spin_lock_irqsave(&mapping->lock, flags);
+	for (i = 0; i < mapping->nr_bitmaps; i++) {
+		start = bitmap_find_next_zero_area(mapping->bitmaps[i],
+				mapping->bits, 0, count, align);
+
+		if (start > mapping->bits)
+			continue;
+
+		bitmap_set(mapping->bitmaps[i], start, count);
+		break;
+	}
+
+	/*
+	 * No unused range found. Try to extend the existing mapping
+	 * and perform a second attempt to reserve an IO virtual
+	 * address range of size bytes.
+	 */
+	if (i == mapping->nr_bitmaps) {
+		if (extend_iommu_mapping(mapping)) {
+			spin_unlock_irqrestore(&mapping->lock, flags);
+			return DMA_MAPPING_ERROR;
+		}
+
+		start = bitmap_find_next_zero_area(mapping->bitmaps[i],
+				mapping->bits, 0, count, align);
+
+		if (start > mapping->bits) {
+			spin_unlock_irqrestore(&mapping->lock, flags);
+			return DMA_MAPPING_ERROR;
+		}
+
+		bitmap_set(mapping->bitmaps[i], start, count);
+	}
+	spin_unlock_irqrestore(&mapping->lock, flags);
+
+	iova = mapping->base + (mapping_size * i);
+	iova += start << PAGE_SHIFT;
+
+	return iova;
+}
+
+static inline void __free_iova(struct dma_iommu_mapping *mapping,
+			       dma_addr_t addr, size_t size)
+{
+	unsigned int start, count;
+	size_t mapping_size = mapping->bits << PAGE_SHIFT;
+	unsigned long flags;
+	dma_addr_t bitmap_base;
+	u32 bitmap_index;
+
+	if (!size)
+		return;
+
+	bitmap_index = (u32) (addr - mapping->base) / (u32) mapping_size;
+	BUG_ON(addr < mapping->base || bitmap_index > mapping->extensions);
+
+	bitmap_base = mapping->base + mapping_size * bitmap_index;
+
+	start = (addr - bitmap_base) >>	PAGE_SHIFT;
+
+	if (addr + size > bitmap_base + mapping_size) {
+		/*
+		 * The address range to be freed reaches into the iova
+		 * range of the next bitmap. This should not happen as
+		 * we don't allow this in __alloc_iova (at the
+		 * moment).
+		 */
+		BUG();
+	} else
+		count = size >> PAGE_SHIFT;
+
+	spin_lock_irqsave(&mapping->lock, flags);
+	bitmap_clear(mapping->bitmaps[bitmap_index], start, count);
+	spin_unlock_irqrestore(&mapping->lock, flags);
+}
+
+/* We'll try 2M, 1M, 64K, and finally 4K; array must end with 0! */
+static const int iommu_order_array[] = { 9, 8, 4, 0 };
+
+static struct page **__iommu_alloc_buffer(struct device *dev, size_t size,
+					  gfp_t gfp, unsigned long attrs,
+					  int coherent_flag)
+{
+	struct page **pages;
+	int count = size >> PAGE_SHIFT;
+	int array_size = count * sizeof(struct page *);
+	int i = 0;
+	int order_idx = 0;
+
+	if (array_size <= PAGE_SIZE)
+		pages = kzalloc(array_size, GFP_KERNEL);
+	else
+		pages = vzalloc(array_size);
+	if (!pages)
+		return NULL;
+
+	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS)
+	{
+		unsigned long order = get_order(size);
+		struct page *page;
+
+		page = dma_alloc_from_contiguous(dev, count, order,
+						 gfp & __GFP_NOWARN);
+		if (!page)
+			goto error;
+
+		__dma_clear_buffer(page, size, coherent_flag);
+
+		for (i = 0; i < count; i++)
+			pages[i] = page + i;
+
+		return pages;
+	}
+
+	/* Go straight to 4K chunks if caller says it's OK. */
+	if (attrs & DMA_ATTR_ALLOC_SINGLE_PAGES)
+		order_idx = ARRAY_SIZE(iommu_order_array) - 1;
+
+	/*
+	 * IOMMU can map any pages, so himem can also be used here
+	 */
+	gfp |= __GFP_NOWARN | __GFP_HIGHMEM;
+
+	while (count) {
+		int j, order;
+
+		order = iommu_order_array[order_idx];
+
+		/* Drop down when we get small */
+		if (__fls(count) < order) {
+			order_idx++;
+			continue;
+		}
+
+		if (order) {
+			/* See if it's easy to allocate a high-order chunk */
+			pages[i] = alloc_pages(gfp | __GFP_NORETRY, order);
+
+			/* Go down a notch at first sign of pressure */
+			if (!pages[i]) {
+				order_idx++;
+				continue;
+			}
+		} else {
+			pages[i] = alloc_pages(gfp, 0);
+			if (!pages[i])
+				goto error;
+		}
+
+		if (order) {
+			split_page(pages[i], order);
+			j = 1 << order;
+			while (--j)
+				pages[i + j] = pages[i] + j;
+		}
+
+		__dma_clear_buffer(pages[i], PAGE_SIZE << order, coherent_flag);
+		i += 1 << order;
+		count -= 1 << order;
+	}
+
+	return pages;
+error:
+	while (i--)
+		if (pages[i])
+			__free_pages(pages[i], 0);
+	kvfree(pages);
+	return NULL;
+}
+
+static int __iommu_free_buffer(struct device *dev, struct page **pages,
+			       size_t size, unsigned long attrs)
+{
+	int count = size >> PAGE_SHIFT;
+	int i;
+
+	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
+		dma_release_from_contiguous(dev, pages[0], count);
+	} else {
+		for (i = 0; i < count; i++)
+			if (pages[i])
+				__free_pages(pages[i], 0);
+	}
+
+	kvfree(pages);
+	return 0;
+}
+
+/*
+ * Create a mapping in device IO address space for specified pages
+ */
+static dma_addr_t
+__iommu_create_mapping(struct device *dev, struct page **pages, size_t size,
+		       unsigned long attrs)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	dma_addr_t dma_addr, iova;
+	int i;
+
+	dma_addr = __alloc_iova(mapping, size);
+	if (dma_addr == DMA_MAPPING_ERROR)
+		return dma_addr;
+
+	iova = dma_addr;
+	for (i = 0; i < count; ) {
+		int ret;
+
+		unsigned int next_pfn = page_to_pfn(pages[i]) + 1;
+		phys_addr_t phys = page_to_phys(pages[i]);
+		unsigned int len, j;
+
+		for (j = i + 1; j < count; j++, next_pfn++)
+			if (page_to_pfn(pages[j]) != next_pfn)
+				break;
+
+		len = (j - i) << PAGE_SHIFT;
+		ret = iommu_map(mapping->domain, iova, phys, len,
+				__dma_info_to_prot(DMA_BIDIRECTIONAL, attrs));
+		if (ret < 0)
+			goto fail;
+		iova += len;
+		i = j;
+	}
+	return dma_addr;
+fail:
+	iommu_unmap(mapping->domain, dma_addr, iova-dma_addr);
+	__free_iova(mapping, dma_addr, size);
+	return DMA_MAPPING_ERROR;
+}
+
+static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t size)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+
+	/*
+	 * add optional in-page offset from iova to size and align
+	 * result to page size
+	 */
+	size = PAGE_ALIGN((iova & ~PAGE_MASK) + size);
+	iova &= PAGE_MASK;
+
+	iommu_unmap(mapping->domain, iova, size);
+	__free_iova(mapping, iova, size);
+	return 0;
+}
+
+static struct page **__atomic_get_pages(void *addr)
+{
+	struct page *page;
+	phys_addr_t phys;
+
+	phys = gen_pool_virt_to_phys(atomic_pool, (unsigned long)addr);
+	page = phys_to_page(phys);
+
+	return (struct page **)page;
+}
+
+static struct page **__iommu_get_pages(void *cpu_addr, unsigned long attrs)
+{
+	if (__in_atomic_pool(cpu_addr, PAGE_SIZE))
+		return __atomic_get_pages(cpu_addr);
+
+	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
+		return cpu_addr;
+
+	return dma_common_find_pages(cpu_addr);
+}
+
+static void *__iommu_alloc_simple(struct device *dev, size_t size, gfp_t gfp,
+				  dma_addr_t *handle, int coherent_flag,
+				  unsigned long attrs)
+{
+	struct page *page;
+	void *addr;
+
+	if (coherent_flag  == COHERENT)
+		addr = __alloc_simple_buffer(dev, size, gfp, &page);
+	else
+		addr = __alloc_from_pool(size, &page);
+	if (!addr)
+		return NULL;
+
+	*handle = __iommu_create_mapping(dev, &page, size, attrs);
+	if (*handle == DMA_MAPPING_ERROR)
+		goto err_mapping;
+
+	return addr;
+
+err_mapping:
+	__free_from_pool(addr, size);
+	return NULL;
+}
+
+static void __iommu_free_atomic(struct device *dev, void *cpu_addr,
+			dma_addr_t handle, size_t size, int coherent_flag)
+{
+	__iommu_remove_mapping(dev, handle, size);
+	if (coherent_flag == COHERENT)
+		__dma_free_buffer(virt_to_page(cpu_addr), size);
+	else
+		__free_from_pool(cpu_addr, size);
+}
+
+static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
+	    dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
+{
+	pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
+	struct page **pages;
+	void *addr = NULL;
+	int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+
+	*handle = DMA_MAPPING_ERROR;
+	size = PAGE_ALIGN(size);
+
+	if (coherent_flag  == COHERENT || !gfpflags_allow_blocking(gfp))
+		return __iommu_alloc_simple(dev, size, gfp, handle,
+					    coherent_flag, attrs);
+
+	/*
+	 * Following is a work-around (a.k.a. hack) to prevent pages
+	 * with __GFP_COMP being passed to split_page() which cannot
+	 * handle them.  The real problem is that this flag probably
+	 * should be 0 on ARM as it is not supported on this
+	 * platform; see CONFIG_HUGETLBFS.
+	 */
+	gfp &= ~(__GFP_COMP);
+
+	pages = __iommu_alloc_buffer(dev, size, gfp, attrs, coherent_flag);
+	if (!pages)
+		return NULL;
+
+	*handle = __iommu_create_mapping(dev, pages, size, attrs);
+	if (*handle == DMA_MAPPING_ERROR)
+		goto err_buffer;
+
+	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
+		return pages;
+
+	addr = dma_common_pages_remap(pages, size, prot,
+				   __builtin_return_address(0));
+	if (!addr)
+		goto err_mapping;
+
+	return addr;
+
+err_mapping:
+	__iommu_remove_mapping(dev, *handle, size);
+err_buffer:
+	__iommu_free_buffer(dev, pages, size, attrs);
+	return NULL;
+}
+
+static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
+		    void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		    unsigned long attrs)
+{
+	struct page **pages = __iommu_get_pages(cpu_addr, attrs);
+	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	int err;
+
+	if (!pages)
+		return -ENXIO;
+
+	if (vma->vm_pgoff >= nr_pages)
+		return -ENXIO;
+
+	if (!dev->dma_coherent)
+		vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
+
+	err = vm_map_pages(vma, pages, nr_pages);
+	if (err)
+		pr_err("Remapping memory failed: %d\n", err);
+
+	return err;
+}
+
+/*
+ * free a page as defined by the above mapping.
+ * Must not be called with IRQs disabled.
+ */
+static void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
+	dma_addr_t handle, unsigned long attrs)
+{
+	int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
+	struct page **pages;
+	size = PAGE_ALIGN(size);
+
+	if (coherent_flag == COHERENT || __in_atomic_pool(cpu_addr, size)) {
+		__iommu_free_atomic(dev, cpu_addr, handle, size, coherent_flag);
+		return;
+	}
+
+	pages = __iommu_get_pages(cpu_addr, attrs);
+	if (!pages) {
+		WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+		return;
+	}
+
+	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
+		dma_common_free_remap(cpu_addr, size);
+
+	__iommu_remove_mapping(dev, handle, size);
+	__iommu_free_buffer(dev, pages, size, attrs);
+}
+
+static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
+				 void *cpu_addr, dma_addr_t dma_addr,
+				 size_t size, unsigned long attrs)
+{
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	struct page **pages = __iommu_get_pages(cpu_addr, attrs);
+
+	if (!pages)
+		return -ENXIO;
+
+	return sg_alloc_table_from_pages(sgt, pages, count, 0, size,
+					 GFP_KERNEL);
+}
+
+/*
+ * Map a part of the scatter-gather list into contiguous io address space
+ */
+static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
+			  size_t size, dma_addr_t *handle,
+			  enum dma_data_direction dir, unsigned long attrs)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+	dma_addr_t iova, iova_base;
+	int ret = 0;
+	unsigned int count;
+	struct scatterlist *s;
+	int prot;
+
+	size = PAGE_ALIGN(size);
+	*handle = DMA_MAPPING_ERROR;
+
+	iova_base = iova = __alloc_iova(mapping, size);
+	if (iova == DMA_MAPPING_ERROR)
+		return -ENOMEM;
+
+	for (count = 0, s = sg; count < (size >> PAGE_SHIFT); s = sg_next(s)) {
+		phys_addr_t phys = page_to_phys(sg_page(s));
+		unsigned int len = PAGE_ALIGN(s->offset + s->length);
+
+		if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+			__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
+
+		prot = __dma_info_to_prot(dir, attrs);
+
+		ret = iommu_map(mapping->domain, iova, phys, len, prot);
+		if (ret < 0)
+			goto fail;
+		count += len >> PAGE_SHIFT;
+		iova += len;
+	}
+	*handle = iova_base;
+
+	return 0;
+fail:
+	iommu_unmap(mapping->domain, iova_base, count * PAGE_SIZE);
+	__free_iova(mapping, iova_base, size);
+	return ret;
+}
+
+/**
+ * arm_iommu_map_sg - map a set of SG buffers for streaming mode DMA
+ * @dev: valid struct device pointer
+ * @sg: list of buffers
+ * @nents: number of buffers to map
+ * @dir: DMA transfer direction
+ *
+ * Map a set of buffers described by scatterlist in streaming mode for DMA.
+ * The scatter gather list elements are merged together (if possible) and
+ * tagged with the appropriate dma address and length. They are obtained via
+ * sg_dma_{address,length}.
+ */
+static int arm_iommu_map_sg(struct device *dev, struct scatterlist *sg,
+		int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+	struct scatterlist *s = sg, *dma = sg, *start = sg;
+	int i, count = 0, ret;
+	unsigned int offset = s->offset;
+	unsigned int size = s->offset + s->length;
+	unsigned int max = dma_get_max_seg_size(dev);
+
+	for (i = 1; i < nents; i++) {
+		s = sg_next(s);
+
+		s->dma_length = 0;
+
+		if (s->offset || (size & ~PAGE_MASK) || size + s->length > max) {
+			ret = __map_sg_chunk(dev, start, size,
+					     &dma->dma_address, dir, attrs);
+			if (ret < 0)
+				goto bad_mapping;
+
+			dma->dma_address += offset;
+			dma->dma_length = size - offset;
+
+			size = offset = s->offset;
+			start = s;
+			dma = sg_next(dma);
+			count += 1;
+		}
+		size += s->length;
+	}
+	ret = __map_sg_chunk(dev, start, size, &dma->dma_address, dir, attrs);
+	if (ret < 0)
+		goto bad_mapping;
+
+	dma->dma_address += offset;
+	dma->dma_length = size - offset;
+
+	return count+1;
+
+bad_mapping:
+	for_each_sg(sg, s, count, i)
+		__iommu_remove_mapping(dev, sg_dma_address(s), sg_dma_len(s));
+	if (ret == -ENOMEM)
+		return ret;
+	return -EINVAL;
+}
+
+/**
+ * arm_iommu_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg
+ * @dev: valid struct device pointer
+ * @sg: list of buffers
+ * @nents: number of buffers to unmap (same as was passed to dma_map_sg)
+ * @dir: DMA transfer direction (same as was passed to dma_map_sg)
+ *
+ * Unmap a set of streaming mode DMA translations.  Again, CPU access
+ * rules concerning calls here are the same as for dma_unmap_single().
+ */
+static void arm_iommu_unmap_sg(struct device *dev,
+			       struct scatterlist *sg, int nents,
+			       enum dma_data_direction dir,
+			       unsigned long attrs)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nents, i) {
+		if (sg_dma_len(s))
+			__iommu_remove_mapping(dev, sg_dma_address(s),
+					       sg_dma_len(s));
+		if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+			__dma_page_dev_to_cpu(sg_page(s), s->offset,
+					      s->length, dir);
+	}
+}
+
+/**
+ * arm_iommu_sync_sg_for_cpu
+ * @dev: valid struct device pointer
+ * @sg: list of buffers
+ * @nents: number of buffers to map (returned from dma_map_sg)
+ * @dir: DMA transfer direction (same as was passed to dma_map_sg)
+ */
+static void arm_iommu_sync_sg_for_cpu(struct device *dev,
+			struct scatterlist *sg,
+			int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *s;
+	int i;
+
+	if (dev->dma_coherent)
+		return;
+
+	for_each_sg(sg, s, nents, i)
+		__dma_page_dev_to_cpu(sg_page(s), s->offset, s->length, dir);
+
+}
+
+/**
+ * arm_iommu_sync_sg_for_device
+ * @dev: valid struct device pointer
+ * @sg: list of buffers
+ * @nents: number of buffers to map (returned from dma_map_sg)
+ * @dir: DMA transfer direction (same as was passed to dma_map_sg)
+ */
+static void arm_iommu_sync_sg_for_device(struct device *dev,
+			struct scatterlist *sg,
+			int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *s;
+	int i;
+
+	if (dev->dma_coherent)
+		return;
+
+	for_each_sg(sg, s, nents, i)
+		__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
+}
+
+/**
+ * arm_iommu_map_page
+ * @dev: valid struct device pointer
+ * @page: page that buffer resides in
+ * @offset: offset into page for start of buffer
+ * @size: size of buffer to map
+ * @dir: DMA transfer direction
+ *
+ * IOMMU aware version of arm_dma_map_page()
+ */
+static dma_addr_t arm_iommu_map_page(struct device *dev, struct page *page,
+	     unsigned long offset, size_t size, enum dma_data_direction dir,
+	     unsigned long attrs)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+	dma_addr_t dma_addr;
+	int ret, prot, len = PAGE_ALIGN(size + offset);
+
+	if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		__dma_page_cpu_to_dev(page, offset, size, dir);
+
+	dma_addr = __alloc_iova(mapping, len);
+	if (dma_addr == DMA_MAPPING_ERROR)
+		return dma_addr;
+
+	prot = __dma_info_to_prot(dir, attrs);
+
+	ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, prot);
+	if (ret < 0)
+		goto fail;
+
+	return dma_addr + offset;
+fail:
+	__free_iova(mapping, dma_addr, len);
+	return DMA_MAPPING_ERROR;
+}
+
+/**
+ * arm_iommu_unmap_page
+ * @dev: valid struct device pointer
+ * @handle: DMA address of buffer
+ * @size: size of buffer (same as passed to dma_map_page)
+ * @dir: DMA transfer direction (same as passed to dma_map_page)
+ *
+ * IOMMU aware version of arm_dma_unmap_page()
+ */
+static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+	dma_addr_t iova = handle & PAGE_MASK;
+	struct page *page;
+	int offset = handle & ~PAGE_MASK;
+	int len = PAGE_ALIGN(size + offset);
+
+	if (!iova)
+		return;
+
+	if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
+		page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
+		__dma_page_dev_to_cpu(page, offset, size, dir);
+	}
+
+	iommu_unmap(mapping->domain, iova, len);
+	__free_iova(mapping, iova, len);
+}
+
+/**
+ * arm_iommu_map_resource - map a device resource for DMA
+ * @dev: valid struct device pointer
+ * @phys_addr: physical address of resource
+ * @size: size of resource to map
+ * @dir: DMA transfer direction
+ */
+static dma_addr_t arm_iommu_map_resource(struct device *dev,
+		phys_addr_t phys_addr, size_t size,
+		enum dma_data_direction dir, unsigned long attrs)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+	dma_addr_t dma_addr;
+	int ret, prot;
+	phys_addr_t addr = phys_addr & PAGE_MASK;
+	unsigned int offset = phys_addr & ~PAGE_MASK;
+	size_t len = PAGE_ALIGN(size + offset);
+
+	dma_addr = __alloc_iova(mapping, len);
+	if (dma_addr == DMA_MAPPING_ERROR)
+		return dma_addr;
+
+	prot = __dma_info_to_prot(dir, attrs) | IOMMU_MMIO;
+
+	ret = iommu_map(mapping->domain, dma_addr, addr, len, prot);
+	if (ret < 0)
+		goto fail;
+
+	return dma_addr + offset;
+fail:
+	__free_iova(mapping, dma_addr, len);
+	return DMA_MAPPING_ERROR;
+}
+
+/**
+ * arm_iommu_unmap_resource - unmap a device DMA resource
+ * @dev: valid struct device pointer
+ * @dma_handle: DMA address to resource
+ * @size: size of resource to map
+ * @dir: DMA transfer direction
+ */
+static void arm_iommu_unmap_resource(struct device *dev, dma_addr_t dma_handle,
+		size_t size, enum dma_data_direction dir,
+		unsigned long attrs)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+	dma_addr_t iova = dma_handle & PAGE_MASK;
+	unsigned int offset = dma_handle & ~PAGE_MASK;
+	size_t len = PAGE_ALIGN(size + offset);
+
+	if (!iova)
+		return;
+
+	iommu_unmap(mapping->domain, iova, len);
+	__free_iova(mapping, iova, len);
+}
+
+static void arm_iommu_sync_single_for_cpu(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+	dma_addr_t iova = handle & PAGE_MASK;
+	struct page *page;
+	unsigned int offset = handle & ~PAGE_MASK;
+
+	if (dev->dma_coherent || !iova)
+		return;
+
+	page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
+	__dma_page_dev_to_cpu(page, offset, size, dir);
+}
+
+static void arm_iommu_sync_single_for_device(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+	dma_addr_t iova = handle & PAGE_MASK;
+	struct page *page;
+	unsigned int offset = handle & ~PAGE_MASK;
+
+	if (dev->dma_coherent || !iova)
+		return;
+
+	page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
+	__dma_page_cpu_to_dev(page, offset, size, dir);
+}
+
+static const struct dma_map_ops iommu_ops = {
+	.alloc		= arm_iommu_alloc_attrs,
+	.free		= arm_iommu_free_attrs,
+	.mmap		= arm_iommu_mmap_attrs,
+	.get_sgtable	= arm_iommu_get_sgtable,
+
+	.map_page		= arm_iommu_map_page,
+	.unmap_page		= arm_iommu_unmap_page,
+	.sync_single_for_cpu	= arm_iommu_sync_single_for_cpu,
+	.sync_single_for_device	= arm_iommu_sync_single_for_device,
+
+	.map_sg			= arm_iommu_map_sg,
+	.unmap_sg		= arm_iommu_unmap_sg,
+	.sync_sg_for_cpu	= arm_iommu_sync_sg_for_cpu,
+	.sync_sg_for_device	= arm_iommu_sync_sg_for_device,
+
+	.map_resource		= arm_iommu_map_resource,
+	.unmap_resource		= arm_iommu_unmap_resource,
+};
+
+/**
+ * arm_iommu_create_mapping
+ * @bus: pointer to the bus holding the client device (for IOMMU calls)
+ * @base: start address of the valid IO address space
+ * @size: maximum size of the valid IO address space
+ *
+ * Creates a mapping structure which holds information about used/unused
+ * IO address ranges, which is required to perform memory allocation and
+ * mapping with IOMMU aware functions.
+ *
+ * The client device need to be attached to the mapping with
+ * arm_iommu_attach_device function.
+ */
+struct dma_iommu_mapping *
+arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, u64 size)
+{
+	unsigned int bits = size >> PAGE_SHIFT;
+	unsigned int bitmap_size = BITS_TO_LONGS(bits) * sizeof(long);
+	struct dma_iommu_mapping *mapping;
+	int extensions = 1;
+	int err = -ENOMEM;
+
+	/* currently only 32-bit DMA address space is supported */
+	if (size > DMA_BIT_MASK(32) + 1)
+		return ERR_PTR(-ERANGE);
+
+	if (!bitmap_size)
+		return ERR_PTR(-EINVAL);
+
+	if (bitmap_size > PAGE_SIZE) {
+		extensions = bitmap_size / PAGE_SIZE;
+		bitmap_size = PAGE_SIZE;
+	}
+
+	mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
+	if (!mapping)
+		goto err;
+
+	mapping->bitmap_size = bitmap_size;
+	mapping->bitmaps = kcalloc(extensions, sizeof(unsigned long *),
+				   GFP_KERNEL);
+	if (!mapping->bitmaps)
+		goto err2;
+
+	mapping->bitmaps[0] = kzalloc(bitmap_size, GFP_KERNEL);
+	if (!mapping->bitmaps[0])
+		goto err3;
+
+	mapping->nr_bitmaps = 1;
+	mapping->extensions = extensions;
+	mapping->base = base;
+	mapping->bits = BITS_PER_BYTE * bitmap_size;
+
+	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:
+	kfree(mapping);
+err:
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(arm_iommu_create_mapping);
+
+static void release_iommu_mapping(struct kref *kref)
+{
+	int i;
+	struct dma_iommu_mapping *mapping =
+		container_of(kref, struct dma_iommu_mapping, kref);
+
+	iommu_domain_free(mapping->domain);
+	for (i = 0; i < mapping->nr_bitmaps; i++)
+		kfree(mapping->bitmaps[i]);
+	kfree(mapping->bitmaps);
+	kfree(mapping);
+}
+
+static int extend_iommu_mapping(struct dma_iommu_mapping *mapping)
+{
+	int next_bitmap;
+
+	if (mapping->nr_bitmaps >= mapping->extensions)
+		return -EINVAL;
+
+	next_bitmap = mapping->nr_bitmaps;
+	mapping->bitmaps[next_bitmap] = kzalloc(mapping->bitmap_size,
+						GFP_ATOMIC);
+	if (!mapping->bitmaps[next_bitmap])
+		return -ENOMEM;
+
+	mapping->nr_bitmaps++;
+
+	return 0;
+}
+
+void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping)
+{
+	if (mapping)
+		kref_put(&mapping->kref, release_iommu_mapping);
+}
+EXPORT_SYMBOL_GPL(arm_iommu_release_mapping);
+
+static int __arm_iommu_attach_device(struct device *dev,
+				     struct dma_iommu_mapping *mapping)
+{
+	int err;
+
+	err = iommu_attach_device(mapping->domain, dev);
+	if (err)
+		return err;
+
+	kref_get(&mapping->kref);
+	to_dma_iommu_mapping(dev) = mapping;
+
+	pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev));
+	return 0;
+}
+
+/**
+ * arm_iommu_attach_device
+ * @dev: valid struct device pointer
+ * @mapping: io address space mapping structure (returned from
+ *	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.
+ */
+int arm_iommu_attach_device(struct device *dev,
+			    struct dma_iommu_mapping *mapping)
+{
+	int err;
+
+	err = __arm_iommu_attach_device(dev, mapping);
+	if (err)
+		return err;
+
+	set_dma_ops(dev, &iommu_ops);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(arm_iommu_attach_device);
+
+/**
+ * arm_iommu_detach_device
+ * @dev: valid struct device pointer
+ *
+ * Detaches the provided device from a previously attached map.
+ * This overwrites the dma_ops pointer with appropriate non-IOMMU ops.
+ */
+void arm_iommu_detach_device(struct device *dev)
+{
+	struct dma_iommu_mapping *mapping;
+
+	mapping = to_dma_iommu_mapping(dev);
+	if (!mapping) {
+		dev_warn(dev, "Not attached\n");
+		return;
+	}
+
+	iommu_detach_device(mapping->domain, dev);
+	kref_put(&mapping->kref, release_iommu_mapping);
+	to_dma_iommu_mapping(dev) = 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);
+
+static void arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
+				    const struct iommu_ops *iommu, bool coherent)
+{
+	struct dma_iommu_mapping *mapping;
+
+	mapping = arm_iommu_create_mapping(dev->bus, dma_base, size);
+	if (IS_ERR(mapping)) {
+		pr_warn("Failed to create %llu-byte IOMMU mapping for device %s\n",
+				size, dev_name(dev));
+		return;
+	}
+
+	if (__arm_iommu_attach_device(dev, mapping)) {
+		pr_warn("Failed to attached device %s to IOMMU_mapping\n",
+				dev_name(dev));
+		arm_iommu_release_mapping(mapping);
+		return;
+	}
+
+	set_dma_ops(dev, &iommu_ops);
+}
+
+static void arm_teardown_iommu_dma_ops(struct device *dev)
+{
+	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+
+	if (!mapping)
+		return;
+
+	arm_iommu_detach_device(dev);
+	arm_iommu_release_mapping(mapping);
+}
+
+#else
+
+static void arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
+				    const struct iommu_ops *iommu, bool coherent)
+{
+}
+
+static void arm_teardown_iommu_dma_ops(struct device *dev) { }
+
+#endif	/* CONFIG_ARM_DMA_USE_IOMMU */
+
+void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+			const struct iommu_ops *iommu, bool coherent)
+{
+	/*
+	 * Due to legacy code that sets the ->dma_coherent flag from a bus
+	 * notifier we can't just assign coherent to the ->dma_coherent flag
+	 * here, but instead have to make sure we only set but never clear it
+	 * for now.
+	 */
+	if (coherent)
+		dev->dma_coherent = true;
+
+	/*
+	 * Don't override the dma_ops if they have already been set. Ideally
+	 * this should be the only location where dma_ops are set, remove this
+	 * check when all other callers of set_dma_ops will have disappeared.
+	 */
+	if (dev->dma_ops)
+		return;
+
+	if (iommu)
+		arm_setup_iommu_dma_ops(dev, dma_base, size, iommu, coherent);
+
+	xen_setup_dma_ops(dev);
+	dev->archdata.dma_ops_setup = true;
+}
+
+void arch_teardown_dma_ops(struct device *dev)
+{
+	if (!dev->archdata.dma_ops_setup)
+		return;
+
+	arm_teardown_iommu_dma_ops(dev);
+	/* Let arch_setup_dma_ops() start again from scratch upon re-probe */
+	set_dma_ops(dev, NULL);
+}
+
+void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir)
+{
+	__dma_page_cpu_to_dev(phys_to_page(paddr), paddr & (PAGE_SIZE - 1),
+			      size, dir);
+}
+
+void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir)
+{
+	__dma_page_dev_to_cpu(phys_to_page(paddr), paddr & (PAGE_SIZE - 1),
+			      size, dir);
+}
+
+void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+		gfp_t gfp, unsigned long attrs)
+{
+	return __dma_alloc(dev, size, dma_handle, gfp,
+			   __get_dma_pgprot(attrs, PAGE_KERNEL), false,
+			   attrs, __builtin_return_address(0));
+}
+
+void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
+		dma_addr_t dma_handle, unsigned long attrs)
+{
+	__arm_dma_free(dev, size, cpu_addr, dma_handle, attrs, false);
+}