sh: Revamp PCI DMA coherence Kconfig bits.

Leaving this configurable caused more trouble than it was ever worth, so
just make it explicit. Boards that are verified one way or the other can
fix up their selects accordingly. We presently default to non-coherent
for most platforms.

Signed-off-by: Paul Mundt <[e-mail]>

arch/sh/Kconfig

···
 config IO_TRAPPED
 	bool
 
+config DMA_COHERENT
+	bool
+
+config DMA_NONCOHERENT
+	def_bool !DMA_COHERENT
+
 source "init/Kconfig"
 
 source "kernel/Kconfig.freezer"
···
 
 config CPU_SHX3
 	bool
+	select DMA_COHERENT
 
 config ARCH_SHMOBILE
 	bool

arch/sh/drivers/pci/Kconfig

···
 	  Find out whether you have a PCI motherboard. PCI is the name of a
 	  bus system, i.e. the way the CPU talks to the other stuff inside
 	  your box. If you have PCI, say Y, otherwise N.
-
-config SH_PCIDMA_NONCOHERENT
-	bool "Cache and PCI noncoherent"
-	depends on PCI
-	default y
-	help
-	  Enable this option if your platform does not have a CPU cache which
-	  remains coherent with PCI DMA. It is safest to say 'Y', although you
-	  will see better performance if you can say 'N', because the PCI DMA
-	  code will not have to flush the CPU's caches. If you have a PCI host
-	  bridge integrated with your SH CPU, refer carefully to the chip specs
-	  to see if you can say 'N' here. Otherwise, leave it as 'Y'.

arch/sh/include/asm/pci.h

···
 /* pci_unmap_{single,page} being a nop depends upon the
  * configuration.
  */
-#ifdef CONFIG_SH_PCIDMA_NONCOHERENT
-#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME)	\
-	dma_addr_t ADDR_NAME;
-#define DECLARE_PCI_UNMAP_LEN(LEN_NAME)		\
-	__u32 LEN_NAME;
-#define pci_unmap_addr(PTR, ADDR_NAME)			\
-	((PTR)->ADDR_NAME)
-#define pci_unmap_addr_set(PTR, ADDR_NAME, VAL)		\
-	(((PTR)->ADDR_NAME) = (VAL))
-#define pci_unmap_len(PTR, LEN_NAME)			\
-	((PTR)->LEN_NAME)
-#define pci_unmap_len_set(PTR, LEN_NAME, VAL)		\
-	(((PTR)->LEN_NAME) = (VAL))
+#ifdef CONFIG_DMA_NONCOHERENT
+#define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME)	dma_addr_t ADDR_NAME;
+#define DECLARE_PCI_UNMAP_LEN(LEN_NAME)		__u32 LEN_NAME;
+#define pci_unmap_addr(PTR, ADDR_NAME)		((PTR)->ADDR_NAME)
+#define pci_unmap_addr_set(PTR, ADDR_NAME, VAL)	(((PTR)->ADDR_NAME) = (VAL))
+#define pci_unmap_len(PTR, LEN_NAME)		((PTR)->LEN_NAME)
+#define pci_unmap_len_set(PTR, LEN_NAME, VAL)	(((PTR)->LEN_NAME) = (VAL))
 #else
 #define DECLARE_PCI_UNMAP_ADDR(ADDR_NAME)
 #define DECLARE_PCI_UNMAP_LEN(LEN_NAME)

arch/sh/kernel/dma-nommu.c

···
 	return nents;
 }
 
+#ifdef CONFIG_DMA_NONCOHERENT
 static void nommu_sync_single(struct device *dev, dma_addr_t addr,
 			      size_t size, enum dma_data_direction dir)
 {
···
 	for_each_sg(sg, s, nelems, i)
 		dma_cache_sync(dev, sg_virt(s), s->length, dir);
 }
+#endif
 
 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,
+#ifdef CONFIG_DMA_NONCOHERENT
 	.sync_single_for_device	= nommu_sync_single,
 	.sync_sg_for_device	= nommu_sync_sg,
+#endif
 	.is_phys		= 1,
 };