sh: uncached mapping helpers.

This adds some helper routines for uncached mapping support. This
simplifies some of the cases where we need to check the uncached mapping
boundaries in addition to giving us a centralized location for building
more complex manipulation on top of.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/mm/init.c

@@ -26,21 +26,6 @@
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 pgd_t swapper_pg_dir[PTRS_PER_PGD];
 
-#ifdef CONFIG_UNCACHED_MAPPING
-/*
- * This is the offset of the uncached section from its cached alias.
- *
- * Legacy platforms handle trivial transitions between cached and
- * uncached segments by making use of the 1:1 mapping relationship in
- * 512MB lowmem, others via a special uncached mapping.
- *
- * Default value only valid in 29 bit mode, in 32bit mode this will be
- * updated by the early PMB initialization code.
- */
-unsigned long cached_to_uncached = 0x20000000;
-unsigned long uncached_size = SZ_512M;
-#endif
-
 #ifdef CONFIG_MMU
 static pte_t *__get_pte_phys(unsigned long addr)
 {
@@ -260,7 +245,7 @@ void __init mem_init(void)
 	memset(empty_zero_page, 0, PAGE_SIZE);
 	__flush_wback_region(empty_zero_page, PAGE_SIZE);
 
-	/* Initialize the vDSO */
+	uncached_init();
 	vsyscall_init();
 
 	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
@@ -303,9 +288,7 @@ void __init mem_init(void)
 		((unsigned long)high_memory - (unsigned long)memory_start) >> 20,
 
 #ifdef CONFIG_UNCACHED_MAPPING
-		(unsigned long)memory_start + cached_to_uncached,
-		(unsigned long)memory_start + cached_to_uncached + uncached_size,
-		uncached_size >> 20,
+		uncached_start, uncached_end, uncached_size >> 20,
 #endif
 
 		(unsigned long)&__init_begin, (unsigned long)&__init_end,