ARM: dma-mapping: Factor out noMMU dma buffer allocation code

This entirely separates the DMA coherent buffer remapping code from
the allocation code, and gets rid of the duplicate copy in the !MMU
section.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NGreg Ungerer <gerg@uclinux.org>

arch/arm/mm/dma-mapping.c

@@ -183,27 +183,13 @@ static int __init consistent_init(void)
 core_initcall(consistent_init);
 
 static void *
-__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
-	    pgprot_t prot)
+__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot)
 {
-	struct page *page;
 	struct arm_vmregion *c;
 
-	size = PAGE_ALIGN(size);
-
-	page = __dma_alloc_buffer(dev, size, gfp);
-	if (!page)
-		goto no_page;
-
-	if (arch_is_coherent()) {
-		*handle = page_to_dma(dev, page);
-		return page_address(page);
-	}
-
 	if (!consistent_pte[0]) {
 		printk(KERN_ERR "%s: not initialised\n", __func__);
 		dump_stack();
-		__dma_free_buffer(page, size);
 		return NULL;
 	}
 
@@ -220,11 +206,6 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 		pte = consistent_pte[idx] + off;
 		c->vm_pages = page;
 
-		/*
-		 * Set the "dma handle"
-		 */
-		*handle = page_to_dma(dev, page);
-
 		do {
 			BUG_ON(!pte_none(*pte));
 
@@ -244,11 +225,6 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 
 		return (void *)c->vm_start;
 	}
-
-	if (page)
-		__dma_free_buffer(page, size);
- no_page:
-	*handle = ~0;
 	return NULL;
 }
 
@@ -315,11 +291,17 @@ static void __dma_free_remap(void *cpu_addr, size_t size)
 
 #else	/* !CONFIG_MMU */
 
+#define __dma_alloc_remap(page, size, gfp, prot)	page_address(page)
+#define __dma_free_remap(addr, size)			do { } while (0)
+
+#endif	/* CONFIG_MMU */
+
 static void *
 __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 	    pgprot_t prot)
 {
 	struct page *page;
+	void *addr;
 
 	*handle = ~0;
 	size = PAGE_ALIGN(size);
@@ -328,13 +310,16 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 	if (!page)
 		return NULL;
 
-	*handle = page_to_dma(dev, page);
-	return page_address(page);
-}
+	if (!arch_is_coherent())
+		addr = __dma_alloc_remap(page, size, gfp, prot);
+	else
+		addr = page_address(page);
 
-#define __dma_free_remap(addr, size)	do { } while (0)
+	if (addr)
+		*handle = page_to_dma(dev, page);
 
-#endif	/* CONFIG_MMU */
+	return addr;
+}
 
 /*
  * Allocate DMA-coherent memory space and return both the kernel remapped