mb/dell: Convert E6400 into a variant

In preparation for adding additional GM45/ICH9 based Dell Latitude
laptops, rework the E6400 port to use a variant scheme so that code can
be shared.

Change-Id: I8094fce56eaaadb20aef173644cd3b2c0b008e95
Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84565
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>

src/mainboard/dell/e6400/Makefile.mk

@@ -1,10 +0,0 @@
-## SPDX-License-Identifier: GPL-2.0-only
-
-bootblock-y += bootblock.c
-
-romstage-y += gpio.c
-
-ramstage-y += cstates.c
-ramstage-y += blc.c
-
-ramstage-$(CONFIG_MAINBOARD_USE_LIBGFXINIT) += gma-mainboard.ads

src/mainboard/dell/gm45_latitude/Kconfig

@@ -1,9 +1,7 @@
 ## SPDX-License-Identifier: GPL-2.0-only
 
-if BOARD_DELL_E6400
-
-config BOARD_SPECIFIC_OPTIONS
-	def_bool y
+config BOARD_DELL_GM45_LATITUDE_COMMON
+	def_bool n
 	select SYSTEM_TYPE_LAPTOP
 	select CPU_INTEL_SOCKET_P
 	select NORTHBRIDGE_INTEL_GM45
@@ -19,16 +17,27 @@ config BOARD_SPECIFIC_OPTIONS
 	select INTEL_GMA_HAVE_VBT
 	select EC_DELL_MEC5035
 
+config BOARD_DELL_E6400
+	select BOARD_DELL_GM45_LATITUDE_COMMON
+
+if BOARD_DELL_GM45_LATITUDE_COMMON
+
 config MAINBOARD_DIR
-	default "dell/e6400"
+	default "dell/gm45_latitude"
 
 config MAINBOARD_PART_NUMBER
 	default "Latitude E6400" if BOARD_DELL_E6400
 
+config OVERRIDE_DEVICETREE
+	default "variants/\$(CONFIG_VARIANT_DIR)/overridetree.cb"
+
+config VARIANT_DIR
+	default "e6400" if BOARD_DELL_E6400
+
 config USBDEBUG_HCD_INDEX
 	default 1
 
 config CBFS_SIZE
 	default 0x1A0000
 
-endif # BOARD_DELL_E6400
+endif # BOARD_DELL_GM45_LATITUDE_COMMON

src/mainboard/dell/gm45_latitude/Makefile.mk

@@ -0,0 +1,11 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
+bootblock-y += bootblock.c
+
+romstage-y += variants/$(VARIANT_DIR)/gpio.c
+
+ramstage-y += cstates.c
+ramstage-y += blc.c
+ramstage-y += variants/$(VARIANT_DIR)/hda_verb.c
+
+ramstage-$(CONFIG_MAINBOARD_USE_LIBGFXINIT) += variants/$(VARIANT_DIR)/gma-mainboard.ads

src/mainboard/dell/gm45_latitude/devicetree.cb

@@ -15,7 +15,6 @@ chip northbridge/intel/gm45
 	register "pci_mmio_size" = "2048"
 
 	device domain 0 on
-		subsystemid 0x1028 0x0233 inherit
 		ops gm45_pci_domain_ops
 
 		device pci 00.0 on end # host bridge

src/mainboard/dell/gm45_latitude/variants/e6400/overridetree.cb

@@ -0,0 +1,7 @@
+## SPDX-License-Identifier: GPL-2.0-or-later
+
+chip northbridge/intel/gm45
+	device domain 0 on
+		subsystemid 0x1028 0x0233 inherit
+	end
+end