This is the first pull request for the new dma-mapping subsystem

In this new subsystem we'll try to properly maintain all the generic
 code related to dma-mapping, and will further consolidate arch code
 into common helpers.
 
 This pull request contains:
 
  - removal of the DMA_ERROR_CODE macro, replacing it with calls
    to ->mapping_error so that the dma_map_ops instances are
    more self contained and can be shared across architectures (me)
  - removal of the ->set_dma_mask method, which duplicates the
    ->dma_capable one in terms of functionality, but requires more
    duplicate code.
  - various updates for the coherent dma pool and related arm code
    (Vladimir)
  - various smaller cleanups (me)
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Merge tag 'dma-mapping-4.13' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping infrastructure from Christoph Hellwig:
 "This is the first pull request for the new dma-mapping subsystem

  In this new subsystem we'll try to properly maintain all the generic
  code related to dma-mapping, and will further consolidate arch code
  into common helpers.

  This pull request contains:

   - removal of the DMA_ERROR_CODE macro, replacing it with calls to
     ->mapping_error so that the dma_map_ops instances are more self
     contained and can be shared across architectures (me)

   - removal of the ->set_dma_mask method, which duplicates the
     ->dma_capable one in terms of functionality, but requires more
     duplicate code.

   - various updates for the coherent dma pool and related arm code
     (Vladimir)

   - various smaller cleanups (me)"

* tag 'dma-mapping-4.13' of git://git.infradead.org/users/hch/dma-mapping: (56 commits)
  ARM: dma-mapping: Remove traces of NOMMU code
  ARM: NOMMU: Set ARM_DMA_MEM_BUFFERABLE for M-class cpus
  ARM: NOMMU: Introduce dma operations for noMMU
  drivers: dma-mapping: allow dma_common_mmap() for NOMMU
  drivers: dma-coherent: Introduce default DMA pool
  drivers: dma-coherent: Account dma_pfn_offset when used with device tree
  dma: Take into account dma_pfn_offset
  dma-mapping: replace dmam_alloc_noncoherent with dmam_alloc_attrs
  dma-mapping: remove dmam_free_noncoherent
  crypto: qat - avoid an uninitialized variable warning
  au1100fb: remove a bogus dma_free_nonconsistent call
  MAINTAINERS: add entry for dma mapping helpers
  powerpc: merge __dma_set_mask into dma_set_mask
  dma-mapping: remove the set_dma_mask method
  powerpc/cell: use the dma_supported method for ops switching
  powerpc/cell: clean up fixed mapping dma_ops initialization
  tile: remove dma_supported and mapping_error methods
  xen-swiotlb: remove xen_swiotlb_set_dma_mask
  arm: implement ->dma_supported instead of ->set_dma_mask
  mips/loongson64: implement ->dma_supported instead of ->set_dma_mask
  ...

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

@@ -29,8 +29,6 @@
 #include <asm/io.h>
 
 struct device;
-extern int bad_dma_address;
-#define DMA_ERROR_CODE bad_dma_address
 
 extern const struct dma_map_ops *dma_ops;
 
@@ -39,9 +37,6 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
 	return dma_ops;
 }
 
-#define HAVE_ARCH_DMA_SUPPORTED 1
-extern int dma_supported(struct device *dev, u64 mask);
-extern int dma_is_consistent(struct device *dev, dma_addr_t dma_handle);
 extern void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 			   enum dma_data_direction direction);
 

arch/hexagon/kernel/dma.c

@@ -25,25 +25,16 @@
 #include <linux/module.h>
 #include <asm/page.h>
 
+#define HEXAGON_MAPPING_ERROR	0
+
 const struct dma_map_ops *dma_ops;
 EXPORT_SYMBOL(dma_ops);
 
-int bad_dma_address;  /*  globals are automatically initialized to zero  */
-
 static inline void *dma_addr_to_virt(dma_addr_t dma_addr)
 {
 	return phys_to_virt((unsigned long) dma_addr);
 }
 
-int dma_supported(struct device *dev, u64 mask)
-{
-	if (mask == DMA_BIT_MASK(32))
-		return 1;
-	else
-		return 0;
-}
-EXPORT_SYMBOL(dma_supported);
-
 static struct gen_pool *coherent_pool;
 
 
@@ -181,7 +172,7 @@ static dma_addr_t hexagon_map_page(struct device *dev, struct page *page,
 	WARN_ON(size == 0);
 
 	if (!check_addr("map_single", dev, bus, size))
-		return bad_dma_address;
+		return HEXAGON_MAPPING_ERROR;
 
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		dma_sync(dma_addr_to_virt(bus), size, dir);
@@ -203,6 +194,11 @@ static void hexagon_sync_single_for_device(struct device *dev,
 	dma_sync(dma_addr_to_virt(dma_handle), size, dir);
 }
 
+static int hexagon_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+	return dma_addr == HEXAGON_MAPPING_ERROR;
+}
+
 const struct dma_map_ops hexagon_dma_ops = {
 	.alloc		= hexagon_dma_alloc_coherent,
 	.free		= hexagon_free_coherent,
@@ -210,6 +206,7 @@ const struct dma_map_ops hexagon_dma_ops = {
 	.map_page	= hexagon_map_page,
 	.sync_single_for_cpu = hexagon_sync_single_for_cpu,
 	.sync_single_for_device = hexagon_sync_single_for_device,
+	.mapping_error	= hexagon_mapping_error,
 	.is_phys	= 1,
 };
 

arch/hexagon/kernel/hexagon_ksyms.c

@@ -40,7 +40,6 @@ EXPORT_SYMBOL(memset);
 /* Additional variables */
 EXPORT_SYMBOL(__phys_offset);
 EXPORT_SYMBOL(_dflt_cache_att);
-EXPORT_SYMBOL(bad_dma_address);
 
 #define DECLARE_EXPORT(name)     \
 	extern void name(void); EXPORT_SYMBOL(name)