s390: Implement dma_{alloc,free}_attrs()

The S390 architecture advertises support for HAVE_DMA_ATTRS when PCI is
enabled. Patches to unify some of the DMA API would like to rely on the
dma_alloc_attrs() and dma_free_attrs() functions to be provided when an
architecture supports DMA attributes.

Rename dma_alloc_coherent() and dma_free_coherent() to dma_alloc_attrs()
and dma_free_attrs() since they are functionally equivalent and alias
the former to the latter for compatibility.

For consistency with other architectures, also reuse the existing symbol
HAVE_DMA_ATTRS defined in arch/Kconfig instead of providing a duplicate.
Select it when PCI is enabled.

While at it, drop a redundant 'default n' from the PCI Kconfig symbol.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-By: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

arch/s390/Kconfig

@@ -498,8 +498,8 @@ config QDIO
 
 menuconfig PCI
 	bool "PCI support"
-	default n
 	depends on 64BIT
+	select HAVE_DMA_ATTRS
 	select PCI_MSI
 	help
 	  Enable PCI support.
@@ -546,9 +546,6 @@ config HAS_DMA
 config NEED_SG_DMA_LENGTH
 	def_bool PCI
 
-config HAVE_DMA_ATTRS
-	def_bool PCI
-
 config NEED_DMA_MAP_STATE
 	def_bool PCI
 

arch/s390/include/asm/dma-mapping.h

@@ -56,24 +56,35 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 	return dma_addr == DMA_ERROR_CODE;
 }
 
-static inline void *dma_alloc_coherent(struct device *dev, size_t size,
-				       dma_addr_t *dma_handle, gfp_t flag)
+#define dma_alloc_coherent(d, s, h, f) dma_alloc_attrs(d, s, h, f, NULL)
+
+static inline void *dma_alloc_attrs(struct device *dev, size_t size,
+				    dma_addr_t *dma_handle, gfp_t flags,
+				    struct dma_attrs *attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
-	void *ret;
+	void *cpu_addr;
+
+	BUG_ON(!ops);
 
-	ret = ops->alloc(dev, size, dma_handle, flag, NULL);
-	debug_dma_alloc_coherent(dev, size, *dma_handle, ret);
-	return ret;
+	cpu_addr = ops->alloc(dev, size, dma_handle, flags, attrs);
+	debug_dma_alloc_coherent(dev, size, *dma_handle, cpu_addr);
+
+	return cpu_addr;
 }
 
-static inline void dma_free_coherent(struct device *dev, size_t size,
-				     void *cpu_addr, dma_addr_t dma_handle)
+#define dma_free_coherent(d, s, c, h) dma_free_attrs(d, s, c, h, NULL)
+
+static inline void dma_free_attrs(struct device *dev, size_t size,
+				  void *cpu_addr, dma_addr_t dma_handle,
+				  struct dma_attrs *attrs)
 {
-	struct dma_map_ops *dma_ops = get_dma_ops(dev);
+	struct dma_map_ops *ops = get_dma_ops(dev);
+
+	BUG_ON(!ops);
 
 	debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);
-	dma_ops->free(dev, size, cpu_addr, dma_handle, NULL);
+	ops->free(dev, size, cpu_addr, dma_handle, attrs);
 }
 
 #endif /* _ASM_S390_DMA_MAPPING_H */