ARM: kill off arch_is_coherent

With ixp2xxx removed, there are no platforms that define arch_is_coherent,
so the last occurrences of arch_is_coherent can be removed. Any new
platform with coherent i/o should use coherent dma mapping functions.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>

arch/arm/include/asm/barrier.h

@@ -44,10 +44,9 @@
 #define rmb()		dsb()
 #define wmb()		mb()
 #else
-#include <asm/memory.h>
-#define mb()	do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
-#define rmb()	do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
-#define wmb()	do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
+#define mb()		barrier()
+#define rmb()		barrier()
+#define wmb()		barrier()
 #endif
 
 #ifndef CONFIG_SMP

arch/arm/include/asm/memory.h

@@ -275,14 +275,6 @@ static inline __deprecated void *bus_to_virt(unsigned long x)
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 #define virt_addr_valid(kaddr)	((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory)
 
-/*
- * Optional coherency support.  Currently used only by selected
- * Intel XSC3-based systems.
- */
-#ifndef arch_is_coherent
-#define arch_is_coherent()		0
-#endif
-
 #endif
 
 #include <asm-generic/memory_model.h>

arch/arm/mm/mmu.c

@@ -421,17 +421,6 @@ static void __init build_mem_type_table(void)
 	cp = &cache_policies[cachepolicy];
 	vecs_pgprot = kern_pgprot = user_pgprot = cp->pte;
 
-	/*
-	 * Enable CPU-specific coherency if supported.
-	 * (Only available on XSC3 at the moment.)
-	 */
-	if (arch_is_coherent() && cpu_is_xsc3()) {
-		mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
-		mem_types[MT_MEMORY].prot_pte |= L_PTE_SHARED;
-		mem_types[MT_MEMORY_DMA_READY].prot_pte |= L_PTE_SHARED;
-		mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
-		mem_types[MT_MEMORY_NONCACHED].prot_pte |= L_PTE_SHARED;
-	}
 	/*
 	 * ARMv6 and above have extended page tables.
 	 */