ram: Introduce K3 AM654 DDR Sub System driver

K3 based AM654 devices has DDR memory subsystem that comprises
Synopys DDR controller, Synopsis DDR phy and wrapper logic to
intergrate these blocks into the device. This DDR subsystem
provides an interface to external SDRAM devices. Adding support
for the initialization of the external SDRAM devices by
configuring the DDRSS registers and using the buitin PHY
routines.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Schuyler Patton <spatton@ti.com>
Signed-off-by: James Doublesin <doublesin@ti.com>
diff --git a/drivers/ram/Kconfig b/drivers/ram/Kconfig
index 54bb4b4..fbf7d7b 100644
--- a/drivers/ram/Kconfig
+++ b/drivers/ram/Kconfig
@@ -43,4 +43,15 @@
 	  the RAM through the use of SPD (Serial Presence Detect) is supported
 	  via device tree settings.
 
+config K3_AM654_DDRSS
+	bool "Enable AM654 DDRSS support"
+	depends on RAM && SOC_K3_AM6
+	help
+	  K3 based AM654 devices has DDR memory subsystem that comprises
+	  Synopys DDR controller, Synopsis DDR phy and wrapper logic to
+	  intergrate these blocks into the device. This DDR subsystem
+	  provides an interface to external SDRAM devices. Enabling this
+	  config add support for the initialization of the external
+	  SDRAM devices connected to DDR subsystem.
+
 source "drivers/ram/stm32mp1/Kconfig"