iommu/samsung: Introduce Exynos sysmmu-v8 driver

Introduce new driver for modern Exynos ARMv8 SoCs, e.g. Exynos850. Also
it's used for Google's GS101 SoC.

This is squashed commit, contains next patches of different authors. See
`iommu-exynos850-dev' branch for details: [1].

Original authors (Samsung):

 - Cho KyongHo <pullip.cho@samsung.com>
 - Hyesoo Yu <hyesoo.yu@samsung.com>
 - Janghyuck Kim <janghyuck.kim@samsung.com>
 - Jinkyu Yang <jinkyu1.yang@samsung.com>

Some improvements were made by Google engineers:

 - Alex <acnwigwe@google.com>
 - Carlos Llamas <cmllamas@google.com>
 - Daniel Mentz <danielmentz@google.com>
 - Erick Reyes <erickreyes@google.com>
 - J. Avila <elavila@google.com>
 - Jonglin Lee <jonglin@google.com>
 - Mark Salyzyn <salyzyn@google.com>
 - Thierry Strudel <tstrudel@google.com>
 - Will McVicker <willmcvicker@google.com>

[1] https://github.com/joe-skb7/linux/tree/iommu-exynos850-dev

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>

drivers/iommu/Kconfig

@@ -452,6 +452,19 @@ config QCOM_IOMMU
 	help
 	  Support for IOMMU on certain Qualcomm SoCs.
 
+config SAMSUNG_IOMMU
+	tristate "Samsung IOMMU Support"
+	select ARM_DMA_USE_IOMMU
+	select IOMMU_DMA
+	select SAMSUNG_IOMMU_GROUP
+	help
+	  Support for IOMMU on Samsung Exynos SoCs.
+
+config SAMSUNG_IOMMU_GROUP
+	tristate "Samsung IOMMU Group Support"
+	help
+	  Support for IOMMU group on Samsung Exynos SoCs.
+
 config HYPERV_IOMMU
 	bool "Hyper-V x2APIC IRQ Handling"
 	depends on HYPERV && X86

drivers/iommu/Makefile

@@ -27,6 +27,9 @@ obj-$(CONFIG_FSL_PAMU) += fsl_pamu.o fsl_pamu_domain.o
 obj-$(CONFIG_S390_IOMMU) += s390-iommu.o
 obj-$(CONFIG_HYPERV_IOMMU) += hyperv-iommu.o
 obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o
+obj-$(CONFIG_SAMSUNG_IOMMU) += samsung_iommu.o
+samsung_iommu-objs += samsung-iommu.o samsung-iommu-fault.o
+obj-$(CONFIG_SAMSUNG_IOMMU_GROUP) += samsung-iommu-group.o
 obj-$(CONFIG_IOMMU_SVA_LIB) += iommu-sva-lib.o io-pgfault.o
 obj-$(CONFIG_SPRD_IOMMU) += sprd-iommu.o
 obj-$(CONFIG_APPLE_DART) += apple-dart.o