This patch adds support for mediatek m4u (MultiMedia Memory Management
Unit).

Signed-off-by: Yong Wu <yong.wu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
Reviewed-by: Robin Murphy <redacted>

---
drivers/iommu/Kconfig     |  16 +
 drivers/iommu/Makefile    |   1 +
 drivers/iommu/mtk_iommu.c | 732 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 749 insertions(+)
 create mode 100644 drivers/iommu/mtk_iommu.c

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index a1e75cb..4922aa8 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig

@@ -318,4 +318,20 @@ config S390_IOMMU
 	help
 	  Support for the IOMMU API for s390 PCI devices.
 
+config MTK_IOMMU
+	bool "MTK IOMMU Support"
+	depends on ARM || ARM64
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	select IOMMU_API
+	select IOMMU_DMA
+	select IOMMU_IO_PGTABLE_ARMV7S
+	select MEMORY
+	select MTK_SMI
+	help
+	  Support for the M4U on certain Mediatek SOCs. M4U is MultiMedia
+	  Memory Management Unit. This option enables remapping of DMA memory
+	  accesses for the multimedia subsystem.
+
+	  If unsure, say N here.
+
 endif # IOMMU_SUPPORT

diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 42fc0c2..44ae2e0 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_INTEL_IOMMU) += intel-iommu.o
 obj-$(CONFIG_INTEL_IOMMU_SVM) += intel-svm.o
 obj-$(CONFIG_IPMMU_VMSA) += ipmmu-vmsa.o
 obj-$(CONFIG_IRQ_REMAP) += intel_irq_remapping.o irq_remapping.o
+obj-$(CONFIG_MTK_IOMMU) += mtk_iommu.o
 obj-$(CONFIG_OMAP_IOMMU) += omap-iommu.o
 obj-$(CONFIG_OMAP_IOMMU_DEBUG) += omap-iommu-debug.o
 obj-$(CONFIG_ROCKCHIP_IOMMU) += rockchip-iommu.o

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
new file mode 100644
index 0000000..60fe97b
--- /dev/null
+++ b/drivers/iommu/mtk_iommu.c

@@ -0,0 +1,732 @@
+/*
+ * Copyright (c) 2015-2016 MediaTek Inc.
+ * Author: Yong Wu <yong.wu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <linux/dma-iommu.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iommu.h>
+#include <linux/iopoll.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_iommu.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <soc/mediatek/smi.h>
+#include <dt-bindings/memory/mt8173-larb-port.h>
+