[PATCH v3 4/5] arm64: introduce pfn_valid_region()

[Jia He <hejianet@gmail.com>]

This is the preparation for further optimizing in early_pfn_valid
on arm64.

Signed-off-by: Jia He <jia.he@hxt-semitech.com>
---
 arch/arm64/include/asm/page.h |  3 ++-
 arch/arm64/mm/init.c          | 25 ++++++++++++++++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 60d02c8..da2cba3 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -38,7 +38,8 @@ extern void clear_page(void *to);
 typedef struct page *pgtable_t;
 
 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
-extern int pfn_valid(unsigned long);
+extern int pfn_valid(unsigned long pfn);
+extern int pfn_valid_region(unsigned long pfn, int *last_idx);
 #endif
 
 #include <asm/memory.h>
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 00e7b90..06433d5 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -290,7 +290,30 @@ int pfn_valid(unsigned long pfn)
 	return memblock_is_map_memory(pfn << PAGE_SHIFT);
 }
 EXPORT_SYMBOL(pfn_valid);
-#endif
+
+int pfn_valid_region(unsigned long pfn, int *last_idx)
+{
+	unsigned long start_pfn, end_pfn;
+	struct memblock_type *type = &memblock.memory;
+
+	if (*last_idx != -1) {
+		start_pfn = PFN_DOWN(type->regions[*last_idx].base);
+		end_pfn= PFN_DOWN(type->regions[*last_idx].base +
+					type->regions[*last_idx].size);
+
+		if (pfn >= start_pfn && pfn < end_pfn)
+			return !memblock_is_nomap(
+				&memblock.memory.regions[*last_idx]);
+	}
+
+	*last_idx = memblock_search_pfn_regions(pfn);
+	if (*last_idx == -1)
+		return false;
+
+	return !memblock_is_nomap(&memblock.memory.regions[*last_idx]);
+}
+EXPORT_SYMBOL(pfn_valid_region);
+#endif /*CONFIG_HAVE_ARCH_PFN_VALID*/
 
 #ifndef CONFIG_SPARSEMEM
 static void __init arm64_memory_present(void)
-- 
2.7.4