sh: Add dma-mapping support for dma_alloc/free_coherent() overrides.

This moves the current dma_alloc/free_coherent() calls to a generic
variant and plugs them in for the nommu default. Other variants can
override the defaults in the dma mapping ops directly.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/dma-mapping.h

@@ -9,6 +9,9 @@ static inline struct dma_map_ops *get_dma_ops(struct device *dev)
 	return dma_ops;
 }
 
+#include <asm-generic/dma-coherent.h>
+#include <asm-generic/dma-mapping-common.h>
+
 static inline int dma_supported(struct device *dev, u64 mask)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
@@ -33,12 +36,6 @@ static inline int dma_set_mask(struct device *dev, u64 mask)
 	return 0;
 }
 
-void *dma_alloc_coherent(struct device *dev, size_t size,
-			 dma_addr_t *dma_handle, gfp_t flag);
-
-void dma_free_coherent(struct device *dev, size_t size,
-		       void *vaddr, dma_addr_t dma_handle);
-
 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 		    enum dma_data_direction dir);
 
@@ -65,7 +62,42 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return dma_addr == 0;
 }
 
-#include <asm-generic/dma-coherent.h>
-#include <asm-generic/dma-mapping-common.h>
+static inline void *dma_alloc_coherent(struct device *dev, size_t size,
+				       dma_addr_t *dma_handle, gfp_t gfp)
+{
+	struct dma_map_ops *ops = get_dma_ops(dev);
+	void *memory;
+
+	if (dma_alloc_from_coherent(dev, size, dma_handle, &memory))
+		return memory;
+	if (!ops->alloc_coherent)
+		return NULL;
+
+	memory = ops->alloc_coherent(dev, size, dma_handle, gfp);
+	debug_dma_alloc_coherent(dev, size, *dma_handle, memory);
+
+	return memory;
+}
+
+static inline void dma_free_coherent(struct device *dev, size_t size,
+				     void *vaddr, dma_addr_t dma_handle)
+{
+	struct dma_map_ops *ops = get_dma_ops(dev);
+
+	WARN_ON(irqs_disabled());	/* for portability */
+
+	if (dma_release_from_coherent(dev, get_order(size), vaddr))
+		return;
+
+	debug_dma_free_coherent(dev, size, vaddr, dma_handle);
+	if (ops->free_coherent)
+		ops->free_coherent(dev, size, vaddr, dma_handle);
+}
+
+/* arch/sh/mm/consistent.c */
+extern void *dma_generic_alloc_coherent(struct device *dev, size_t size,
+					dma_addr_t *dma_addr, gfp_t flag);
+extern void dma_generic_free_coherent(struct device *dev, size_t size,
+				      void *vaddr, dma_addr_t dma_handle);
 
 #endif /* __ASM_SH_DMA_MAPPING_H */

arch/sh/kernel/dma-nommu.c

@@ -61,6 +61,8 @@ static void nommu_sync_sg(struct device *dev, struct scatterlist *sg,
 }
 
 struct dma_map_ops nommu_dma_ops = {
+	.alloc_coherent		= dma_generic_alloc_coherent,
+	.free_coherent		= dma_generic_free_coherent,
 	.map_page		= nommu_map_page,
 	.map_sg			= nommu_map_sg,
 	.sync_single_for_device	= nommu_sync_single,

arch/sh/mm/consistent.c

@@ -33,15 +33,12 @@ static int __init dma_init(void)
 }
 fs_initcall(dma_init);
 
-void *dma_alloc_coherent(struct device *dev, size_t size,
+void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 				 dma_addr_t *dma_handle, gfp_t gfp)
 {
 	void *ret, *ret_nocache;
 	int order = get_order(size);
 
-	if (dma_alloc_from_coherent(dev, size, dma_handle, &ret))
-		return ret;
-
 	ret = (void *)__get_free_pages(gfp, order);
 	if (!ret)
 		return NULL;
@@ -63,30 +60,21 @@ void *dma_alloc_coherent(struct device *dev, size_t size,
 
 	*dma_handle = virt_to_phys(ret);
 
-	debug_dma_alloc_coherent(dev, size, *dma_handle, ret_nocache);
-
 	return ret_nocache;
 }
-EXPORT_SYMBOL(dma_alloc_coherent);
 
-void dma_free_coherent(struct device *dev, size_t size,
+void dma_generic_free_coherent(struct device *dev, size_t size,
 			       void *vaddr, dma_addr_t dma_handle)
 {
 	int order = get_order(size);
 	unsigned long pfn = dma_handle >> PAGE_SHIFT;
 	int k;
 
-	WARN_ON(irqs_disabled());	/* for portability */
-
-	if (dma_release_from_coherent(dev, order, vaddr))
-		return;
-
-	debug_dma_free_coherent(dev, size, vaddr, dma_handle);
 	for (k = 0; k < (1 << order); k++)
 		__free_pages(pfn_to_page(pfn + k), 0);
+
 	iounmap(vaddr);
 }
-EXPORT_SYMBOL(dma_free_coherent);
 
 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 		    enum dma_data_direction direction)