Merge branch 'for-3.15' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping

Pull DMA-mapping updates from Marek Szyprowski:
 "This contains extension for more efficient handling of io address
  space for dma-mapping subsystem for ARM architecture"

* 'for-3.15' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  arm: dma-mapping: remove order parameter from arm_iommu_create_mapping()
  arm: dma-mapping: Add support to extend DMA IOMMU mappings

2 files changed, 121 insertions, 35 deletions

diff --git a/arch/arm/include/asm/dma-iommu.h b/arch/arm/include/asm/dma-iommu.h
index a8c56acc8c9..eec0a12c5c1 100644
--- a/arch/arm/include/asm/dma-iommu.h
+++ b/arch/arm/include/asm/dma-iommu.h
@@ -13,9 +13,12 @@ struct dma_iommu_mapping {
 	/* iommu specific data */
 	struct iommu_domain	*domain;
 
-	void			*bitmap;
-	size_t			bits;
-	unsigned int		order;
+	unsigned long		**bitmaps;	/* array of bitmaps */
+	unsigned int		nr_bitmaps;	/* nr of elements in array */
+	unsigned int		extensions;
+	size_t			bitmap_size;	/* size of a single bitmap */
+	size_t			bits;		/* per bitmap */
+	unsigned int		size;		/* per bitmap */
 	dma_addr_t		base;
 
 	spinlock_t		lock;
@@ -23,8 +26,7 @@ struct dma_iommu_mapping {
 };
 
 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);
 
 void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);
 
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 11b3914660d..4fe42ce720d 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1069,6 +1069,8 @@ 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)
 {
@@ -1076,41 +1078,87 @@ static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
 	unsigned int align = 0;
 	unsigned int count, start;
 	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) +
-		 (1 << mapping->order) - 1) >> mapping->order;
-
-	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;
 	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);
 }
 
@@ -1875,8 +1923,7 @@ struct dma_map_ops iommu_coherent_ops = {
  * 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
@@ -1886,38 +1933,54 @@ 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->size = bitmap_size << PAGE_SHIFT;
 	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:
@@ -1927,14 +1990,35 @@ 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)