EDAC/versal: Add a Xilinx Versal memory controller driver

Add a EDAC driver for the RAS capabilities on the Xilinx integrated DDR
Memory Controllers (DDRMCs) which support both DDR4 and LPDDR4/4X memory
interfaces. It has four programmable Network-on-Chip (NoC) interface
ports and is designed to handle multiple streams of traffic. The driver
reports correctable and uncorrectable errors, and also creates debugfs
entries for testing through error injection.

  [ bp:
   - Add a pointer to the documentation about the register unlock code.
   - Squash in a fix for a Smatch static checker issue as reported by
     Dan Carpenter:
     https://lore.kernel.org/r/a4db6f93-8e5f-4d55-a7b8-b5a987d48a58@moroto.mountain
  ]

Co-developed-by: Sai Krishna Potthuri <sai.krishna.potthuri@amd.com>
Signed-off-by: Sai Krishna Potthuri <sai.krishna.potthuri@amd.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231005101242.14621-3-shubhrajyoti.datta@amd.com

MAINTAINERS

@@ -23719,6 +23719,13 @@ F:	Documentation/devicetree/bindings/media/xilinx/
 F:	drivers/media/platform/xilinx/
 F:	include/uapi/linux/xilinx-v4l2-controls.h
 
+XILINX VERSAL EDAC DRIVER
+M:	Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
+M:	Sai Krishna Potthuri <sai.krishna.potthuri@amd.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/memory-controllers/xlnx,versal-ddrmc-edac.yaml
+F:	drivers/edac/versal_edac.c
+
 XILINX WATCHDOG DRIVER
 M:	Srinivas Neeli <srinivas.neeli@amd.com>
 R:	Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>

drivers/edac/Kconfig

@@ -561,4 +561,16 @@ config EDAC_NPCM
 	  error detection (in-line ECC in which a section 1/8th of the memory
 	  device used to store data is used for ECC storage).
 
+config EDAC_VERSAL
+	tristate "Xilinx Versal DDR Memory Controller"
+	depends on ARCH_ZYNQMP || COMPILE_TEST
+	help
+	  Support for error detection and correction on the Xilinx Versal DDR
+	  memory controller.
+
+	  Report both single bit errors (CE) and double bit errors (UE).
+	  Support injecting both correctable and uncorrectable errors
+	  for debugging purposes.
+
+
 endif # EDAC

drivers/edac/Makefile

@@ -86,3 +86,4 @@ obj-$(CONFIG_EDAC_BLUEFIELD)		+= bluefield_edac.o
 obj-$(CONFIG_EDAC_DMC520)		+= dmc520_edac.o
 obj-$(CONFIG_EDAC_NPCM)			+= npcm_edac.o
 obj-$(CONFIG_EDAC_ZYNQMP)		+= zynqmp_edac.o
+obj-$(CONFIG_EDAC_VERSAL)		+= versal_edac.o