HACK: dma-mapping: add non-zeroing coherent alloc function

Add a new function, dma_malloc_from_coherent(), which
takes a parameter that specifies if the allocated memory
should be zero-ed or not. Modify dma_alloc_from_coherent
to call dma_malloc_from_coherent with the flag set to
true in order to zero the memory. In this way
dma_alloc_from_coherent behaves the same as before.

Signed-off-by: Angela Stegmaier <angelabaker@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>

include/linux/dma-mapping.h

@@ -161,7 +161,8 @@ static inline int is_device_dma_capable(struct device *dev)
  * Don't use them in device drivers.
  */
 int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
-				       dma_addr_t *dma_handle, void **ret);
+				dma_addr_t *dma_handle, void **ret,
+				bool zero);
 int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr);
 
 int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma,
@@ -173,7 +174,7 @@ int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *cpu_addr,
 				  size_t size, int *ret);
 
 #else
-#define dma_alloc_from_dev_coherent(dev, size, handle, ret) (0)
+#define dma_alloc_from_dev_coherent(dev, size, handle, ret, zero) (0)
 #define dma_release_from_dev_coherent(dev, order, vaddr) (0)
 #define dma_mmap_from_dev_coherent(dev, vma, vaddr, order, ret) (0)
 
@@ -505,9 +506,9 @@ dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr,
 #define arch_dma_alloc_attrs(dev)	(true)
 #endif
 
-static inline void *dma_alloc_attrs(struct device *dev, size_t size,
-				       dma_addr_t *dma_handle, gfp_t flag,
-				       unsigned long attrs)
+static inline void *dma_malloc_attrs(struct device *dev, size_t size,
+				     dma_addr_t *dma_handle, gfp_t flag,
+				     unsigned long attrs, bool zero)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
 	void *cpu_addr;
@@ -515,7 +516,7 @@ static inline void *dma_alloc_attrs(struct device *dev, size_t size,
 	BUG_ON(!ops);
 	WARN_ON_ONCE(dev && !dev->coherent_dma_mask);
 
-	if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
+	if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr, zero))
 		return cpu_addr;
 
 	/* let the implementation decide on the zone to allocate from: */
@@ -531,6 +532,13 @@ static inline void *dma_alloc_attrs(struct device *dev, size_t size,
 	return cpu_addr;
 }
 
+static inline void *dma_alloc_attrs(struct device *dev, size_t size,
+				    dma_addr_t *dma_handle, gfp_t flag,
+				    unsigned long attrs)
+{
+	return dma_malloc_attrs(dev, size, dma_handle, flag, attrs, true);
+}
+
 static inline void dma_free_attrs(struct device *dev, size_t size,
 				     void *cpu_addr, dma_addr_t dma_handle,
 				     unsigned long attrs)
@@ -563,6 +571,12 @@ static inline void *dma_alloc_coherent(struct device *dev, size_t size,
 	return dma_alloc_attrs(dev, size, dma_handle, flag, 0);
 }
 
+static inline void *dma_malloc_coherent(struct device *dev, size_t size,
+					dma_addr_t *dma_handle, gfp_t flag)
+{
+	return dma_malloc_attrs(dev, size, dma_handle, flag, 0, false);
+}
+
 static inline void dma_free_coherent(struct device *dev, size_t size,
 		void *cpu_addr, dma_addr_t dma_handle)
 {

kernel/dma/coherent.c

@@ -161,7 +161,7 @@ void *dma_mark_declared_memory_occupied(struct device *dev,
 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
 
 static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,
-		ssize_t size, dma_addr_t *dma_handle)
+		ssize_t size, dma_addr_t *dma_handle, bool zero)
 {
 	int order = get_order(size);
 	unsigned long flags;
@@ -183,7 +183,8 @@ static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,
 	*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
 	ret = mem->virt_base + (pageno << PAGE_SHIFT);
 	spin_unlock_irqrestore(&mem->spinlock, flags);
-	memset(ret, 0, size);
+	if (zero)
+		memset(ret, 0, size);
 	return ret;
 err:
 	spin_unlock_irqrestore(&mem->spinlock, flags);
@@ -205,14 +206,14 @@ err:
  * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
  */
 int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
-		dma_addr_t *dma_handle, void **ret)
+		dma_addr_t *dma_handle, void **ret, bool zero)
 {
 	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);
 
 	if (!mem)
 		return 0;
 
-	*ret = __dma_alloc_from_coherent(mem, size, dma_handle);
+	*ret = __dma_alloc_from_coherent(mem, size, dma_handle, zero);
 	if (*ret)
 		return 1;
 
@@ -231,7 +232,7 @@ void *dma_alloc_from_global_coherent(ssize_t size, dma_addr_t *dma_handle)
 		return NULL;
 
 	return __dma_alloc_from_coherent(dma_coherent_default_memory, size,
-			dma_handle);
+			dma_handle, true);
 }
 
 static int __dma_release_from_coherent(struct dma_coherent_mem *mem,