mb/google/brya: add BASEBOARD_DIR to support different baseboard

In order to support different baseboard configuration, we
add the BASEBOARD_DIR to switch the directory. The expected
structure looks like:

mb
..|_ google
.........|_ brya
.............. |_ variants
.....................|_ baseboard
..............................|_ brya
....................................|_ gpio.c
....................................|_ memory.c
....................................|_ devicetree
..............................|_ brask
....................................|_ gpio.c
....................................|_ memory.c
....................................|_ devicetree
......................|_ brya_variant1
......................|_ brya_variant2
......................|_ ...
......................|_ brask_variant1
......................|_ brask_variant2
......................|_ ...
...............|_ <all mb common code>

BUG=b:191472401
BRANCH=None
TEST=build pass

Change-Id: Ic99e42dbbd27fa3e1f6cb3a1b5daee1c8c7b1083
Signed-off-by: Zhuohao Lee <zhuohao@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56308
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com>

src/mainboard/google/brya/Kconfig

@@ -35,6 +35,10 @@ config BOARD_GOOGLE_BASEBOARD_BRYA
 
 if BOARD_GOOGLE_BASEBOARD_BRYA
 
+config BASEBOARD_DIR
+	string
+	default "brya" if BOARD_GOOGLE_BASEBOARD_BRYA
+
 config CHROMEOS
 	select CHROMEOS_DRAM_PART_NUMBER_IN_CBI
 	select EC_GOOGLE_CHROMEEC_SWITCHES
@@ -42,7 +46,7 @@ config CHROMEOS
 	select VBOOT_LID_SWITCH
 
 config DEVICETREE
-	default "variants/baseboard/devicetree.cb"
+	default "variants/baseboard/\$(CONFIG_BASEBOARD_DIR)/devicetree.cb"
 
 config DRIVER_TPM_I2C_BUS
 	hex
@@ -64,7 +68,7 @@ config MAINBOARD_DIR
 
 config MAINBOARD_FAMILY
 	string
-	default "Google_Brya"
+	default "Google_Brya" if BOARD_GOOGLE_BASEBOARD_BRYA
 
 config MAINBOARD_PART_NUMBER
 	default "Brya" if BOARD_GOOGLE_BRYA0

src/mainboard/google/brya/Makefile.inc

@@ -10,11 +10,12 @@ ramstage-y += mainboard.c
 ramstage-y += ec.c
 
 VARIANT_DIR:=$(call strip_quotes,$(CONFIG_VARIANT_DIR))
+BASEBOARD_DIR:=$(call strip_quotes,$(CONFIG_BASEBOARD_DIR))
 
-subdirs-y += variants/baseboard
+subdirs-y += variants/baseboard/$(BASEBOARD_DIR)
 subdirs-y += variants/$(VARIANT_DIR)
 subdirs-y += variants/$(VARIANT_DIR)/memory
 subdirs-y += spd
 
-CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/baseboard/include
+CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/baseboard/$(BASEBOARD_DIR)/include
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/$(VARIANT_DIR)/include