1 files changed, 341 insertions, 96 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 076c26d4386..1f88db06b13 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -9,6 +9,7 @@
  *
  *  DMA uncached mapping support.
  */
+#include <linux/bootmem.h>
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/gfp.h>
@@ -157,9 +158,47 @@ struct dma_map_ops arm_coherent_dma_ops = {
 };
 EXPORT_SYMBOL(arm_coherent_dma_ops);
 
+static int __dma_supported(struct device *dev, u64 mask, bool warn)
+{
+	unsigned long max_dma_pfn;
+
+	/*
+	 * If the mask allows for more memory than we can address,
+	 * and we actually have that much memory, then we must
+	 * indicate that DMA to this device is not supported.
+	 */
+	if (sizeof(mask) != sizeof(dma_addr_t) &&
+	    mask > (dma_addr_t)~0 &&
+	    dma_to_pfn(dev, ~0) < max_pfn) {
+		if (warn) {
+			dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n",
+				 mask);
+			dev_warn(dev, "Driver did not use or check the return value from dma_set_coherent_mask()?\n");
+		}
+		return 0;
+	}
+
+	max_dma_pfn = min(max_pfn, arm_dma_pfn_limit);
+
+	/*
+	 * Translate the device's DMA mask to a PFN limit.  This
+	 * PFN number includes the page which we can DMA to.
+	 */
+	if (dma_to_pfn(dev, mask) < max_dma_pfn) {
+		if (warn)
+			dev_warn(dev, "Coherent DMA mask %#llx (pfn %#lx-%#lx) covers a smaller range of system memory than the DMA zone pfn 0x0-%#lx\n",
+				 mask,
+				 dma_to_pfn(dev, 0), dma_to_pfn(dev, mask) + 1,
+				 max_dma_pfn + 1);
+		return 0;
+	}
+
+	return 1;
+}
+
 static u64 get_coherent_dma_mask(struct device *dev)
 {
-	u64 mask = (u64)arm_dma_limit;
+	u64 mask = (u64)DMA_BIT_MASK(32);
 
 	if (dev) {
 		mask = dev->coherent_dma_mask;
@@ -173,12 +212,8 @@ static u64 get_coherent_dma_mask(struct device *dev)
 			return 0;
 		}
 
-		if ((~mask) & (u64)arm_dma_limit) {
-			dev_warn(dev, "coherent DMA mask %#llx is smaller "
-				 "than system GFP_DMA mask %#llx\n",
-				 mask, (u64)arm_dma_limit);
+		if (!__dma_supported(dev, mask, true))
 			return 0;
-		}
 	}
 
 	return mask;
@@ -186,13 +221,24 @@ static u64 get_coherent_dma_mask(struct device *dev)
 
 static void __dma_clear_buffer(struct page *page, size_t size)
 {
-	void *ptr;
 	/*
 	 * Ensure that the allocated pages are zeroed, and that any data
 	 * lurking in the kernel direct-mapped region is invalidated.
 	 */
-	ptr = page_address(page);
-	if (ptr) {
+	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);
+			dmac_flush_range(ptr, ptr + PAGE_SIZE);
+			kunmap_atomic(ptr);
+			page++;
+			size -= PAGE_SIZE;
+		}
+		outer_flush_range(base, end);
+	} else {
+		void *ptr = page_address(page);
 		memset(ptr, 0, size);
 		dmac_flush_range(ptr, ptr + size);
 		outer_flush_range(__pa(ptr), __pa(ptr) + size);
@@ -238,12 +284,10 @@ static void __dma_free_buffer(struct page *page, size_t size)
 }
 
 #ifdef CONFIG_MMU
-#ifdef CONFIG_HUGETLB_PAGE
-#error ARM Coherent DMA allocator does not (yet) support huge TLB
-#endif
 
 static void *__alloc_from_contiguous(struct device *dev, size_t size,
-				     pgprot_t prot, struct page **ret_page);
+				     pgprot_t prot, struct page **ret_page,
+				     const void *caller);
 
 static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
 				 pgprot_t prot, struct page **ret_page,
@@ -329,7 +373,8 @@ void __init init_dma_coherent_pool_size(unsigned long size)
 static int __init atomic_pool_init(void)
 {
 	struct dma_pool *pool = &atomic_pool;
-	pgprot_t prot = pgprot_dmacoherent(pgprot_kernel);
+	pgprot_t prot = pgprot_dmacoherent(PAGE_KERNEL);
+	gfp_t gfp = GFP_KERNEL | GFP_DMA;
 	unsigned long nr_pages = pool->size >> PAGE_SHIFT;
 	unsigned long *bitmap;
 	struct page *page;
@@ -345,11 +390,12 @@ static int __init atomic_pool_init(void)
 	if (!pages)
 		goto no_pages;
 
-	if (IS_ENABLED(CONFIG_CMA))
-		ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page);
+	if (dev_get_cma_area(NULL))
+		ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page,
+					      atomic_pool_init);
 	else
-		ptr = __alloc_remap_buffer(NULL, pool->size, GFP_KERNEL, prot,
-					   &page, NULL);
+		ptr = __alloc_remap_buffer(NULL, pool->size, gfp, prot, &page,
+					   atomic_pool_init);
 	if (ptr) {
 		int i;
 
@@ -415,12 +461,21 @@ void __init dma_contiguous_remap(void)
 		map.type = MT_MEMORY_DMA_READY;
 
 		/*
-		 * Clear previous low-memory mapping
+		 * 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);
 	}
 }
@@ -441,7 +496,6 @@ static void __dma_remap(struct page *page, size_t size, pgprot_t prot)
 	unsigned end = start + size;
 
 	apply_to_page_range(&init_mm, start, size, __dma_update_pte, &prot);
-	dsb();
 	flush_tlb_kernel_range(start, end);
 }
 
@@ -542,27 +596,41 @@ static int __free_from_pool(void *start, size_t size)
 }
 
 static void *__alloc_from_contiguous(struct device *dev, size_t size,
-				     pgprot_t prot, struct page **ret_page)
+				     pgprot_t prot, struct page **ret_page,
+				     const void *caller)
 {
 	unsigned long order = get_order(size);
 	size_t count = size >> PAGE_SHIFT;
 	struct page *page;
+	void *ptr;
 
 	page = dma_alloc_from_contiguous(dev, count, order);
 	if (!page)
 		return NULL;
 
 	__dma_clear_buffer(page, size);
-	__dma_remap(page, size, prot);
 
+	if (PageHighMem(page)) {
+		ptr = __dma_alloc_remap(page, size, GFP_KERNEL, prot, caller);
+		if (!ptr) {
+			dma_release_from_contiguous(dev, page, count);
+			return NULL;
+		}
+	} else {
+		__dma_remap(page, size, prot);
+		ptr = page_address(page);
+	}
 	*ret_page = page;
-	return page_address(page);
+	return ptr;
 }
 
 static void __free_from_contiguous(struct device *dev, struct page *page,
-				   size_t size)
+				   void *cpu_addr, size_t size)
 {
-	__dma_remap(page, size, pgprot_kernel);
+	if (PageHighMem(page))
+		__dma_free_remap(cpu_addr, size);
+	else
+		__dma_remap(page, size, PAGE_KERNEL);
 	dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
 }
 
@@ -583,9 +651,9 @@ static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot)
 #define __get_dma_pgprot(attrs, prot)	__pgprot(0)
 #define __alloc_remap_buffer(dev, size, gfp, prot, ret, c)	NULL
 #define __alloc_from_pool(size, ret_page)			NULL
-#define __alloc_from_contiguous(dev, size, prot, ret)		NULL
+#define __alloc_from_contiguous(dev, size, prot, ret, c)	NULL
 #define __free_from_pool(cpu_addr, size)			0
-#define __free_from_contiguous(dev, page, size)			do { } while (0)
+#define __free_from_contiguous(dev, page, cpu_addr, size)	do { } while (0)
 #define __dma_free_remap(cpu_addr, size)			do { } while (0)
 
 #endif	/* CONFIG_MMU */
@@ -640,12 +708,12 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 
 	if (is_coherent || nommu())
 		addr = __alloc_simple_buffer(dev, size, gfp, &page);
-	else if (gfp & GFP_ATOMIC)
+	else if (!(gfp & __GFP_WAIT))
 		addr = __alloc_from_pool(size, &page);
-	else if (!IS_ENABLED(CONFIG_CMA))
+	else if (!dev_get_cma_area(dev))
 		addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller);
 	else
-		addr = __alloc_from_contiguous(dev, size, prot, &page);
+		addr = __alloc_from_contiguous(dev, size, prot, &page, caller);
 
 	if (addr)
 		*handle = pfn_to_dma(dev, page_to_pfn(page));
@@ -660,7 +728,7 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 		    gfp_t gfp, struct dma_attrs *attrs)
 {
-	pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
+	pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
 	void *memory;
 
 	if (dma_alloc_from_coherent(dev, size, handle, &memory))
@@ -673,7 +741,7 @@ void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 static void *arm_coherent_dma_alloc(struct device *dev, size_t size,
 	dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs)
 {
-	pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
+	pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
 	void *memory;
 
 	if (dma_alloc_from_coherent(dev, size, handle, &memory))
@@ -731,7 +799,7 @@ static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
 		__dma_free_buffer(page, size);
 	} else if (__free_from_pool(cpu_addr, size)) {
 		return;
-	} else if (!IS_ENABLED(CONFIG_CMA)) {
+	} else if (!dev_get_cma_area(dev)) {
 		__dma_free_remap(cpu_addr, size);
 		__dma_free_buffer(page, size);
 	} else {
@@ -739,7 +807,7 @@ static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
 		 * Non-atomic allocations cannot be freed with IRQs disabled
 		 */
 		WARN_ON(irqs_disabled());
-		__free_from_contiguous(dev, page, size);
+		__free_from_contiguous(dev, page, cpu_addr, size);
 	}
 }
 
@@ -795,16 +863,17 @@ static void dma_cache_maint_page(struct page *page, unsigned long offset,
 		if (PageHighMem(page)) {
 			if (len + offset > PAGE_SIZE)
 				len = PAGE_SIZE - offset;
-			vaddr = kmap_high_get(page);
-			if (vaddr) {
-				vaddr += offset;
-				op(vaddr, len, dir);
-				kunmap_high(page);
-			} else if (cache_is_vipt()) {
-				/* unmapped pages might still be cached */
+
+			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;
@@ -825,7 +894,7 @@ static void dma_cache_maint_page(struct page *page, unsigned long offset,
 static void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
 	size_t size, enum dma_data_direction dir)
 {
-	unsigned long paddr;
+	phys_addr_t paddr;
 
 	dma_cache_maint_page(page, off, size, dir, dmac_map_area);
 
@@ -841,20 +910,35 @@ static void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
 static void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
 	size_t size, enum dma_data_direction dir)
 {
-	unsigned long paddr = page_to_phys(page) + off;
+	phys_addr_t paddr = page_to_phys(page) + off;
 
 	/* FIXME: non-speculating: not required */
-	/* don't bother invalidating if DMA to device */
-	if (dir != DMA_TO_DEVICE)
+	/* 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);
+		dma_cache_maint_page(page, off, size, dir, dmac_unmap_area);
+	}
 
 	/*
-	 * Mark the D-cache clean for this page to avoid extra flushing.
+	 * Mark the D-cache clean for these pages to avoid extra flushing.
 	 */
-	if (dir != DMA_TO_DEVICE && off == 0 && size >= PAGE_SIZE)
-		set_bit(PG_dcache_clean, &page->flags);
+	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;
+		}
+	}
 }
 
 /**
@@ -965,9 +1049,7 @@ void arm_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
  */
 int dma_supported(struct device *dev, u64 mask)
 {
-	if (mask < (u64)arm_dma_limit)
-		return 0;
-	return 1;
+	return __dma_supported(dev, mask, false);
 }
 EXPORT_SYMBOL(dma_supported);
 
@@ -994,45 +1076,98 @@ fs_initcall(dma_debug_do_init);
 
 /* 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;
 
-	count = ((PAGE_ALIGN(size) >> PAGE_SHIFT) +
-		 (1 << mapping->order) - 1) >> mapping->order;
+	if (order > CONFIG_ARM_DMA_IOMMU_ALIGNMENT)
+		order = CONFIG_ARM_DMA_IOMMU_ALIGNMENT;
 
-	if (order > mapping->order)
-		align = (1 << (order - mapping->order)) - 1;
+	count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	align = (1 << order) - 1;
 
 	spin_lock_irqsave(&mapping->lock, flags);
-	start = bitmap_find_next_zero_area(mapping->bitmap, mapping->bits, 0,
-					   count, align);
-	if (start > mapping->bits) {
-		spin_unlock_irqrestore(&mapping->lock, flags);
-		return DMA_ERROR_CODE;
+	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;
 	}
 
-	bitmap_set(mapping->bitmap, start, count);
+	/*
+	 * 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_ERROR_CODE;
+		}
+
+		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_ERROR_CODE;
+		}
+
+		bitmap_set(mapping->bitmaps[i], start, count);
+	}
 	spin_unlock_irqrestore(&mapping->lock, flags);
 
-	return mapping->base + (start << (mapping->order + PAGE_SHIFT));
+	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 = (addr - mapping->base) >>
-			     (mapping->order + PAGE_SHIFT);
-	unsigned int count = ((size >> PAGE_SHIFT) +
-			      (1 << mapping->order) - 1) >> mapping->order;
+	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->bitmap, start, count);
+	bitmap_clear(mapping->bitmaps[bitmap_index], start, count);
 	spin_unlock_irqrestore(&mapping->lock, flags);
 }
 
@@ -1068,12 +1203,17 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size,
 		return pages;
 	}
 
+	/*
+	 * IOMMU can map any pages, so himem can also be used here
+	 */
+	gfp |= __GFP_NOWARN | __GFP_HIGHMEM;
+
 	while (count) {
 		int j, order = __fls(count);
 
-		pages[i] = alloc_pages(gfp | __GFP_NOWARN, order);
+		pages[i] = alloc_pages(gfp, order);
 		while (!pages[i] && order)
-			pages[i] = alloc_pages(gfp | __GFP_NOWARN, --order);
+			pages[i] = alloc_pages(gfp, --order);
 		if (!pages[i])
 			goto error;
 
@@ -1182,7 +1322,8 @@ __iommu_create_mapping(struct device *dev, struct page **pages, size_t size)
 				break;
 
 		len = (j - i) << PAGE_SHIFT;
-		ret = iommu_map(mapping->domain, iova, phys, len, 0);
+		ret = iommu_map(mapping->domain, iova, phys, len,
+				IOMMU_READ|IOMMU_WRITE);
 		if (ret < 0)
 			goto fail;
 		iova += len;
@@ -1257,26 +1398,35 @@ err_mapping:
 	return NULL;
 }
 
-static void __iommu_free_atomic(struct device *dev, struct page **pages,
+static void __iommu_free_atomic(struct device *dev, void *cpu_addr,
 				dma_addr_t handle, size_t size)
 {
 	__iommu_remove_mapping(dev, handle, size);
-	__free_from_pool(page_address(pages[0]), size);
+	__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, struct dma_attrs *attrs)
 {
-	pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
+	pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
 	struct page **pages;
 	void *addr = NULL;
 
 	*handle = DMA_ERROR_CODE;
 	size = PAGE_ALIGN(size);
 
-	if (gfp & GFP_ATOMIC)
+	if (!(gfp & __GFP_WAIT))
 		return __iommu_alloc_atomic(dev, size, handle);
 
+	/*
+	 * 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);
 	if (!pages)
 		return NULL;
@@ -1335,16 +1485,17 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
 			  dma_addr_t handle, struct dma_attrs *attrs)
 {
-	struct page **pages = __iommu_get_pages(cpu_addr, attrs);
+	struct page **pages;
 	size = PAGE_ALIGN(size);
 
-	if (!pages) {
-		WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+	if (__in_atomic_pool(cpu_addr, size)) {
+		__iommu_free_atomic(dev, cpu_addr, handle, size);
 		return;
 	}
 
-	if (__in_atomic_pool(cpu_addr, size)) {
-		__iommu_free_atomic(dev, pages, handle, size);
+	pages = __iommu_get_pages(cpu_addr, attrs);
+	if (!pages) {
+		WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
 		return;
 	}
 
@@ -1371,6 +1522,27 @@ static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
 					 GFP_KERNEL);
 }
 
+static int __dma_direction_to_prot(enum dma_data_direction dir)
+{
+	int prot;
+
+	switch (dir) {
+	case DMA_BIDIRECTIONAL:
+		prot = IOMMU_READ | IOMMU_WRITE;
+		break;
+	case DMA_TO_DEVICE:
+		prot = IOMMU_READ;
+		break;
+	case DMA_FROM_DEVICE:
+		prot = IOMMU_WRITE;
+		break;
+	default:
+		prot = 0;
+	}
+
+	return prot;
+}
+
 /*
  * Map a part of the scatter-gather list into contiguous io address space
  */
@@ -1384,6 +1556,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
 	int ret = 0;
 	unsigned int count;
 	struct scatterlist *s;
+	int prot;
 
 	size = PAGE_ALIGN(size);
 	*handle = DMA_ERROR_CODE;
@@ -1400,7 +1573,9 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
 			!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
 			__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
 
-		ret = iommu_map(mapping->domain, iova, phys, len, 0);
+		prot = __dma_direction_to_prot(dir);
+
+		ret = iommu_map(mapping->domain, iova, phys, len, prot);
 		if (ret < 0)
 			goto fail;
 		count += len >> PAGE_SHIFT;
@@ -1599,13 +1774,15 @@ static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *p
 {
 	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
 	dma_addr_t dma_addr;
-	int ret, len = PAGE_ALIGN(size + offset);
+	int ret, prot, len = PAGE_ALIGN(size + offset);
 
 	dma_addr = __alloc_iova(mapping, len);
 	if (dma_addr == DMA_ERROR_CODE)
 		return dma_addr;
 
-	ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, 0);
+	prot = __dma_direction_to_prot(dir);
+
+	ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, prot);
 	if (ret < 0)
 		goto fail;
 
@@ -1732,6 +1909,8 @@ struct dma_map_ops iommu_ops = {
 	.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,
+
+	.set_dma_mask		= arm_dma_set_mask,
 };
 
 struct dma_map_ops iommu_coherent_ops = {
@@ -1745,14 +1924,15 @@ struct dma_map_ops iommu_coherent_ops = {
 
 	.map_sg		= arm_coherent_iommu_map_sg,
 	.unmap_sg	= arm_coherent_iommu_unmap_sg,
+
+	.set_dma_mask	= arm_dma_set_mask,
 };
 
 /**
  * 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: size of the valid IO address space
- * @order: accuracy of the IO addresses allocations
+ * @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
@@ -1762,59 +1942,97 @@ 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,
-			 int order)
+arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size)
 {
-	unsigned int count = size >> (PAGE_SHIFT + order);
-	unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
+	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;
 
-	if (!count)
+	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 = kzalloc(bitmap_size, GFP_KERNEL);
-	if (!mapping->bitmap)
+	mapping->bitmap_size = bitmap_size;
+	mapping->bitmaps = kzalloc(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;
-	mapping->order = order;
+
 	spin_lock_init(&mapping->lock);
 
 	mapping->domain = iommu_domain_alloc(bus);
 	if (!mapping->domain)
-		goto err3;
+		goto err4;
 
 	kref_init(&mapping->kref);
 	return mapping;
+err4:
+	kfree(mapping->bitmaps[0]);
 err3:
-	kfree(mapping->bitmap);
+	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);
-	kfree(mapping->bitmap);
+	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);
 
 /**
  * arm_iommu_attach_device
@@ -1843,5 +2061,32 @@ int arm_iommu_attach_device(struct device *dev,
 	pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev));
 	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 voids the dma operations (dma_map_ops pointer)
+ */
+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);
+	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