dma-mapping: consolidate dma_{alloc,free}_noncoherent

Most architectures do not support non-coherent allocations and either
define dma_{alloc,free}_noncoherent to their coherent versions or stub
them out.

Openrisc uses dma_{alloc,free}_attrs to implement them, and only Mips
implements them directly.

This patch moves the Openrisc version to common code, and handles the
DMA_ATTR_NON_CONSISTENT case in the mips dma_map_ops instance.

Note that actual non-coherent allocations require a dma_cache_sync
implementation, so if non-coherent allocations didn't work on
an architecture before this patch they still won't work after it.

[jcmvbkbc@gmail.com: fix xtensa]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 15 insertions, 11 deletions

diff --git a/arch/mips/include/asm/dma-mapping.h b/arch/mips/include/asm/dma-mapping.h
index b197595134ba..709b2ba79cc3 100644
--- a/arch/mips/include/asm/dma-mapping.h
+++ b/arch/mips/include/asm/dma-mapping.h
@@ -64,10 +64,4 @@ dma_set_mask(struct device *dev, u64 mask)
 extern void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 	       enum dma_data_direction direction);
 
-void *dma_alloc_noncoherent(struct device *dev, size_t size,
-			   dma_addr_t *dma_handle, gfp_t flag);
-
-void dma_free_noncoherent(struct device *dev, size_t size,
-			 void *vaddr, dma_addr_t dma_handle);
-
 #endif /* _ASM_DMA_MAPPING_H */
diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index 6c0fd13fa8e8..a914dc1cb6d1 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -112,7 +112,7 @@ static gfp_t massage_gfp_flags(const struct device *dev, gfp_t gfp)
 	return gfp | dma_flag;
 }
 
-void *dma_alloc_noncoherent(struct device *dev, size_t size,
+static void *mips_dma_alloc_noncoherent(struct device *dev, size_t size,
 	dma_addr_t * dma_handle, gfp_t gfp)
 {
 	void *ret;
@@ -128,7 +128,6 @@ void *dma_alloc_noncoherent(struct device *dev, size_t size,
 
 	return ret;
 }
-EXPORT_SYMBOL(dma_alloc_noncoherent);
 
 static void *mips_dma_alloc_coherent(struct device *dev, size_t size,
 	dma_addr_t * dma_handle, gfp_t gfp, struct dma_attrs *attrs)
@@ -137,6 +136,13 @@ static void *mips_dma_alloc_coherent(struct device *dev, size_t size,
 	struct page *page = NULL;
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 
+	/*
+	 * XXX: seems like the coherent and non-coherent implementations could
+	 * be consolidated.
+	 */
+	if (dma_get_attr(DMA_ATTR_NON_CONSISTENT, attrs))
+		return mips_dma_alloc_noncoherent(dev, size, dma_handle, gfp);
+
 	gfp = massage_gfp_flags(dev, gfp);
 
 	if (IS_ENABLED(CONFIG_DMA_CMA) && !(gfp & GFP_ATOMIC))
@@ -161,13 +167,12 @@ static void *mips_dma_alloc_coherent(struct device *dev, size_t size,
 }
 
 
-void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
-	dma_addr_t dma_handle)
+static void mips_dma_free_noncoherent(struct device *dev, size_t size,
+		void *vaddr, dma_addr_t dma_handle)
 {
 	plat_unmap_dma_mem(dev, dma_handle, size, DMA_BIDIRECTIONAL);
 	free_pages((unsigned long) vaddr, get_order(size));
 }
-EXPORT_SYMBOL(dma_free_noncoherent);
 
 static void mips_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
 	dma_addr_t dma_handle, struct dma_attrs *attrs)
@@ -176,6 +181,11 @@ static void mips_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	struct page *page = NULL;
 
+	if (dma_get_attr(DMA_ATTR_NON_CONSISTENT, attrs)) {
+		mips_dma_free_noncoherent(dev, size, vaddr, dma_handle);
+		return;
+	}
+
 	plat_unmap_dma_mem(dev, dma_handle, size, DMA_BIDIRECTIONAL);
 
 	if (!plat_device_is_coherent(dev) && !hw_coherentio)