[4/5] DMA: Add functions to preallocate DMA memory dor devices

Commit Message

Guennadi Liakhovetski Aug. 19, 2010, 2:40 p.m. UTC

None

Patch

diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
index 8efdfd4..9eb2856 100644
--- a/drivers/base/dma-coherent.c
+++ b/drivers/base/dma-coherent.c
@@ -170,3 +170,53 @@  int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
 	return 0;
 }
 EXPORT_SYMBOL(dma_release_from_coherent);
+
+int dma_preallocate_coherent_memory(struct device *dev, size_t size, gfp_t gfp,
+				    int flags)
+{
+	int pages = size >> PAGE_SHIFT;
+	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
+	dma_addr_t dma_handle;
+	void *buf;
+
+	if (!(flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) || !dev)
+		return -EINVAL;
+
+	if (!size)
+		return 0;
+
+	buf = dma_alloc_coherent(NULL, size, &dma_handle, gfp);
+	if (!buf)
+		return -ENOMEM;
+
+	dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem) + bitmap_size, gfp);
+	if (!dev->dma_mem)
+		goto ealloc;
+
+	dev->dma_mem->virt_base = buf;
+	dev->dma_mem->device_base = dma_handle;
+	dev->dma_mem->size = pages;
+	dev->dma_mem->flags = flags;
+
+	return 0;
+
+ealloc:
+	dma_free_coherent(dev, size, buf, dma_handle);
+
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(dma_preallocate_coherent_memory);
+
+void dma_release_preallocated_memory(struct device *dev)
+{
+	struct dma_coherent_mem *mem = dev->dma_mem;
+
+	if (!mem)
+		return;
+
+	dev->dma_mem = NULL;
+	dma_free_coherent(dev, mem->size << PAGE_SHIFT, mem->virt_base,
+			  mem->device_base);
+	kfree(mem);
+}
+EXPORT_SYMBOL(dma_release_preallocated_memory);
diff --git a/include/asm-generic/dma-coherent.h b/include/asm-generic/dma-coherent.h
index a92bc09..08a66a1 100644
--- a/include/asm-generic/dma-coherent.h
+++ b/include/asm-generic/dma-coherent.h
@@ -21,6 +21,8 @@  void dma_release_declared_memory(struct device *dev);
 
 void *dma_mark_declared_memory_occupied(struct device *dev,
 				  dma_addr_t device_addr, size_t size);
+int dma_preallocate_coherent_memory(struct device *dev, size_t size, gfp_t gfp, int flags);
+void dma_release_preallocated_memory(struct device *dev);
 #else
 #define dma_alloc_from_coherent(dev, size, handle, ret) (0)
 #define dma_release_from_coherent(dev, order, vaddr) (0)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 77ce97f..0912abf 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -177,6 +177,18 @@  dma_mark_declared_memory_occupied(struct device *dev,
 {
 	return ERR_PTR(-EBUSY);
 }
+
+static inline int
+dma_preallocate_coherent_memory(struct device *dev, size_t size, gfp_t gfp, int flags)
+{
+	return -EINVAL;
+}
+
+static inline void
+dma_release_preallocated_memory(struct device *dev)
+{
+}
+
 #endif
 
 /*