UFS: Add UFS support

UFS support is compiled into gem5 kernels by default.  However, it
is still disabled in the dts file by default.  Uncommenting it in
the dts *should* make it work with an appropriately-configured
system.

Signed-off-by: Christopher Daniel Emmons <chris.emmons@arm.com>

arch/arm/boot/dts/vexpress-v2m-rs1-gem5.dtsi

diff --git a/arch/arm/boot/dts/vexpress-v2m-rs1-gem5.dtsi b/arch/arm/boot/dts/vexpress-v2m-rs1-gem5.dtsi
index b3c5abe..b234b20 100644
--- a/arch/arm/boot/dts/vexpress-v2m-rs1-gem5.dtsi
+++ b/arch/arm/boot/dts/vexpress-v2m-rs1-gem5.dtsi
@@ -259,6 +259,13 @@
 				reg-shift = <2>;
 			};
 
+/*** Uncomment to boot with UFS
+			ufshcd-pltfm@1b0000 {
+				compatible = "ufshcd-pltfm";
+				reg = <0x1b0000 0x100 0x1b0100 0x1000>;
+				interrupts = <10>;
+			};
+*/
 			clcd@1f0000 {
 				status = "disabled";
 				compatible = "arm,pl111", "arm,primecell";

arch/arm/configs/vexpress_gem5_defconfig

diff --git a/arch/arm/configs/vexpress_gem5_defconfig b/arch/arm/configs/vexpress_gem5_defconfig
index f992256c..554d332 100644
--- a/arch/arm/configs/vexpress_gem5_defconfig
+++ b/arch/arm/configs/vexpress_gem5_defconfig
@@ -80,7 +80,9 @@
 # CONFIG_SCSI_PROC_FS is not set
 CONFIG_BLK_DEV_SD=y
 CONFIG_CHR_DEV_SG=y
-# CONFIG_SCSI_LOWLEVEL is not set
+CONFIG_SCSI_LOWLEVEL
+CONFIG_SCSI_UFSHCD=y
+CONFIG_SCSI_UFSHCD_PLATFORM=y
 CONFIG_HAVE_PATA_PLATFORM=y
 CONFIG_ATA=y
 CONFIG_SATA_PMP=y