[PATCH] iommu/mediatek: Use totalram_pages to setup enable_4GB

[Miles Chen <miles.chen@mediatek.com>]

To build this driver as a kernel module, we cannot use
the unexported symbol "max_pfn" to setup enable_4GB.

Use totalram_pages() instead to setup enable_4GB.

Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yong Wu <yong.wu@mediatek.com>
Cc: Chao Hao <chao.hao@mediatek.com>
---
 drivers/iommu/mtk_iommu.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 5f4d6df59cf6..c2798a6e0e38 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -3,7 +3,6 @@
  * Copyright (c) 2015-2016 MediaTek Inc.
  * Author: Yong Wu <yong.wu@mediatek.com>
  */
-#include <linux/memblock.h>
 #include <linux/bug.h>
 #include <linux/clk.h>
 #include <linux/component.h>
@@ -626,8 +625,8 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
 
-	/* Whether the current dram is over 4GB */
-	data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT));
+	/* Whether the current dram is over 4GB, note: DRAM start at 1GB  */
+	data->enable_4GB = !!(totalram_pages() > ((SZ_2G + SZ_1G) >> PAGE_SHIFT));
 	if (!data->plat_data->has_4gb_mode)
 		data->enable_4GB = false;
 
-- 
2.18.0