diff --git a/arch/csky/kernel/setup.c b/arch/csky/kernel/setup.c
index 819a9a7bf786..0481f4e34538 100644
--- a/arch/csky/kernel/setup.c
+++ b/arch/csky/kernel/setup.c
@@ -26,7 +26,9 @@ struct screen_info screen_info = {
 
 static void __init csky_memblock_init(void)
 {
-	unsigned long zone_size[MAX_NR_ZONES];
+	unsigned long lowmem_size = PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);
+	unsigned long sseg_size = PFN_DOWN(SSEG_SIZE - PHYS_OFFSET_OFFSET);
+	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
 	signed long size;
 
 	memblock_reserve(__pa(_stext), _end - _stext);
@@ -36,28 +38,22 @@ static void __init csky_memblock_init(void)
 
 	memblock_dump_all();
 
-	memset(zone_size, 0, sizeof(zone_size));
-
 	min_low_pfn = PFN_UP(memblock_start_of_DRAM());
 	max_low_pfn = max_pfn = PFN_DOWN(memblock_end_of_DRAM());
 
 	size = max_pfn - min_low_pfn;
 
-	if (size <= PFN_DOWN(SSEG_SIZE - PHYS_OFFSET_OFFSET))
-		zone_size[ZONE_NORMAL] = size;
-	else if (size < PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET)) {
-		zone_size[ZONE_NORMAL] =
-				PFN_DOWN(SSEG_SIZE - PHYS_OFFSET_OFFSET);
-		max_low_pfn = min_low_pfn + zone_size[ZONE_NORMAL];
-	} else {
-		zone_size[ZONE_NORMAL] =
-				PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);
-		max_low_pfn = min_low_pfn + zone_size[ZONE_NORMAL];
+	if (size >= lowmem_size) {
+		max_low_pfn = min_low_pfn + lowmem_size;
 		write_mmu_msa1(read_mmu_msa0() + SSEG_SIZE);
+	} else if (size > sseg_size) {
+		max_low_pfn = min_low_pfn + sseg_size;
 	}
 
+	max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
+
 #ifdef CONFIG_HIGHMEM
-	zone_size[ZONE_HIGHMEM] = max_pfn - max_low_pfn;
+	max_zone_pfn[ZONE_HIGHMEM] = max_pfn;
 
 	highstart_pfn = max_low_pfn;
 	highend_pfn   = max_pfn;
@@ -66,7 +62,7 @@ static void __init csky_memblock_init(void)
 
 	dma_contiguous_reserve(0);
 
-	free_area_init_node(0, zone_size, min_low_pfn, NULL);
+	free_area_init(max_zone_pfn);
 }
 
 void __init setup_arch(char **cmdline_p)