powerpc/dma: stop overriding dma_get_required_mask

The ppc_md and pci_controller_ops methods are unused now and can be
removed.  The dma_nommu implementation is generic to the generic one
except for using max_pfn instead of calling into the memblock API,
and all other dma_map_ops instances implement a method of their own.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/device.h

@@ -59,6 +59,4 @@ struct pdev_archdata {
 	u64 dma_mask;
 };
 
-#define ARCH_HAS_DMA_GET_REQUIRED_MASK
-
 #endif /* _ASM_POWERPC_DEVICE_H */

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

@@ -112,7 +112,5 @@ static inline void set_dma_offset(struct device *dev, dma_addr_t off)
 
 #define HAVE_ARCH_DMA_SET_MASK 1
 
-extern u64 __dma_get_required_mask(struct device *dev);
-
 #endif /* __KERNEL__ */
 #endif	/* _ASM_DMA_MAPPING_H */

arch/powerpc/include/asm/machdep.h

@@ -47,9 +47,7 @@ struct machdep_calls {
 #endif
 #endif /* CONFIG_PPC64 */
 
-	/* Platform set_dma_mask and dma_get_required_mask overrides */
 	int		(*dma_set_mask)(struct device *dev, u64 dma_mask);
-	u64		(*dma_get_required_mask)(struct device *dev);
 
 	int		(*probe)(void);
 	void		(*setup_arch)(void); /* Optional, may be NULL */

arch/powerpc/include/asm/pci-bridge.h

@@ -46,7 +46,6 @@ struct pci_controller_ops {
 #endif
 
 	int             (*dma_set_mask)(struct pci_dev *pdev, u64 dma_mask);
-	u64		(*dma_get_required_mask)(struct pci_dev *pdev);
 
 	void		(*shutdown)(struct pci_controller *hose);
 };

arch/powerpc/kernel/dma.c

@@ -318,35 +318,6 @@ int dma_set_mask(struct device *dev, u64 dma_mask)
 }
 EXPORT_SYMBOL(dma_set_mask);
 
-u64 __dma_get_required_mask(struct device *dev)
-{
-	const struct dma_map_ops *dma_ops = get_dma_ops(dev);
-
-	if (unlikely(dma_ops == NULL))
-		return 0;
-
-	if (dma_ops->get_required_mask)
-		return dma_ops->get_required_mask(dev);
-
-	return DMA_BIT_MASK(8 * sizeof(dma_addr_t));
-}
-
-u64 dma_get_required_mask(struct device *dev)
-{
-	if (ppc_md.dma_get_required_mask)
-		return ppc_md.dma_get_required_mask(dev);
-
-	if (dev_is_pci(dev)) {
-		struct pci_dev *pdev = to_pci_dev(dev);
-		struct pci_controller *phb = pci_bus_to_host(pdev->bus);
-		if (phb->controller_ops.dma_get_required_mask)
-			return phb->controller_ops.dma_get_required_mask(pdev);
-	}
-
-	return __dma_get_required_mask(dev);
-}
-EXPORT_SYMBOL_GPL(dma_get_required_mask);
-
 static int __init dma_init(void)
 {
 #ifdef CONFIG_IBMVIO

kernel/dma/mapping.c

@@ -207,7 +207,6 @@ int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 }
 EXPORT_SYMBOL(dma_mmap_attrs);
 
-#ifndef ARCH_HAS_DMA_GET_REQUIRED_MASK
 static u64 dma_default_get_required_mask(struct device *dev)
 {
 	u32 low_totalram = ((max_pfn - 1) << PAGE_SHIFT);
@@ -238,7 +237,6 @@ u64 dma_get_required_mask(struct device *dev)
 	return dma_default_get_required_mask(dev);
 }
 EXPORT_SYMBOL_GPL(dma_get_required_mask);
-#endif
 
 #ifndef arch_dma_alloc_attrs
 #define arch_dma_alloc_attrs(dev)	(true)