[ARM] dma: add validation of DMA params

Validate the direction argument like x86 does.  In addition,
validate the dma_unmap_* parameters against those passed to
dma_map_* when using the DMA bounce code.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 22aec95..f030f07 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -289,6 +289,7 @@
 
 	if (buf) {
 		BUG_ON(buf->size != size);
+		BUG_ON(buf->direction != dir);
 
 		dev_dbg(dev,
 			"%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
@@ -334,7 +335,7 @@
 	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
 		__func__, ptr, size, dir);
 
-	BUG_ON(dir == DMA_NONE);
+	BUG_ON(!valid_dma_direction(dir));
 
 	return map_single(dev, ptr, size, dir);
 }
@@ -346,7 +347,7 @@
 	dev_dbg(dev, "%s(page=%p,off=%#lx,size=%zx,dir=%x)\n",
 		__func__, page, offset, size, dir);
 
-	BUG_ON(dir == DMA_NONE);
+	BUG_ON(!valid_dma_direction(dir));
 
 	return map_single(dev, page_address(page) + offset, size, dir);
 }
@@ -365,8 +366,6 @@
 	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
 		__func__, (void *) dma_addr, size, dir);
 
-	BUG_ON(dir == DMA_NONE);
-
 	unmap_single(dev, dma_addr, size, dir);
 }
 EXPORT_SYMBOL(dma_unmap_single);
@@ -383,6 +382,8 @@
 	if (!buf)
 		return 1;
 
+	BUG_ON(buf->direction != dir);
+
 	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
 		__func__, buf->ptr, virt_to_dma(dev, buf->ptr),
 		buf->safe, buf->safe_dma_addr);
@@ -410,6 +411,8 @@
 	if (!buf)
 		return 1;
 
+	BUG_ON(buf->direction != dir);
+
 	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
 		__func__, buf->ptr, virt_to_dma(dev, buf->ptr),
 		buf->safe, buf->safe_dma_addr);