scsi: ufs: ufs-exynos: Add UFS host support for Exynos SoCs

This patch introduces Exynos UFS host controller driver which mainly
handles vendor-specific operations including link startup, power mode
change and hibernation/unhibernation.

[robot: drivers/scsi/ufs/ufs-exynos.c:931:8-10:
 WARNING: possible condition with no effect (if == else)
]

Link: https://lore.kernel.org/r/20200528011658.71590-10-alim.akhtar@samsung.com
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Tested-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Reviewed-by: Kiwoong Kim <kwmad.kim@samsung.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Seungwon Jeon <essuuj@gmail.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/Kconfig

@@ -160,3 +160,15 @@ config SCSI_UFS_BSG
 
 	  Select this if you need a bsg device node for your UFS controller.
 	  If unsure, say N.
+
+config SCSI_UFS_EXYNOS
+	bool "EXYNOS specific hooks to UFS controller platform driver"
+	depends on SCSI_UFSHCD_PLATFORM && (ARCH_EXYNOS || COMPILE_TEST)
+	select PHY_SAMSUNG_UFS
+	help
+	  This selects the EXYNOS specific additions to UFSHCD platform driver.
+	  UFS host on EXYNOS includes HCI and UNIPRO layer, and associates with
+	  UFS-PHY driver.
+
+	  Select this if you have UFS host controller on EXYNOS chipset.
+	  If unsure, say N.

drivers/scsi/ufs/Makefile

@@ -4,6 +4,7 @@ obj-$(CONFIG_SCSI_UFS_DWC_TC_PCI) += tc-dwc-g210-pci.o ufshcd-dwc.o tc-dwc-g210.
 obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o ufshcd-dwc.o tc-dwc-g210.o
 obj-$(CONFIG_SCSI_UFS_CDNS_PLATFORM) += cdns-pltfrm.o
 obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
+obj-$(CONFIG_SCSI_UFS_EXYNOS) += ufs-exynos.o
 obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
 ufshcd-core-y				+= ufshcd.o ufs-sysfs.o
 ufshcd-core-$(CONFIG_SCSI_UFS_BSG)	+= ufs_bsg.o