mb/google/brya: Add GPIO stubs

Add stubbed out GPIO configuration and perform GPIO initialization
during bootblock and ramstage.

BUG=b:174266035
TEST=Build Test

Signed-off-by: Eric Lai <ericr_lai@compal.corp-partner.google.com>
Change-Id: Ia658ab4b466242cf8658abb239f19a9c0a03849a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48065
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/mainboard/google/brya/Kconfig

@@ -26,4 +26,8 @@ config MAINBOARD_PART_NUMBER
 	string
 	default "brya" if BOARD_GOOGLE_BRYA0
 
+config VARIANT_DIR
+	string
+	default "brya0" if BOARD_GOOGLE_BRYA0
+
 endif # BOARD_GOOGLE_BASEBOARD_BRYA

src/mainboard/google/brya/Makefile.inc

@@ -4,5 +4,10 @@ romstage-y += romstage.c
 
 ramstage-y += mainboard.c
 
+VARIANT_DIR:=$(call strip_quotes,$(CONFIG_VARIANT_DIR))
+
 subdirs-y += variants/baseboard
+subdirs-y += variants/$(VARIANT_DIR)
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/baseboard/include
+CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/$(VARIANT_DIR)/include

src/mainboard/google/brya/bootblock.c

@@ -1,8 +1,12 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
+#include <baseboard/variants.h>
 #include <bootblock_common.h>
 
 void bootblock_mainboard_init(void)
 {
-	/* TODO: Perform mainboard initialization */
+	const struct pad_config *pads;
+	size_t num;
+	pads = variant_early_gpio_table(&num);
+	gpio_configure_pads(pads, num);
 }

src/mainboard/google/brya/mainboard.c

@@ -1,10 +1,14 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
+#include <baseboard/variants.h>
 #include <device/device.h>
 
 static void mainboard_init(void *chip_info)
 {
-	/* TODO: Perform mainboard initialization */
+	const struct pad_config *pads;
+	size_t num;
+	pads = variant_gpio_table(&num);
+	gpio_configure_pads(pads, num);
 }
 
 static void mainboard_enable(struct device *dev)

src/mainboard/google/brya/variants/baseboard/Makefile.inc

@@ -0,0 +1,3 @@
+bootblock-y += gpio.c
+
+ramstage-y += gpio.c

src/mainboard/google/brya/variants/baseboard/gpio.c

@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <baseboard/gpio.h>
+#include <baseboard/variants.h>
+#include <commonlib/helpers.h>
+
+/* Pad configuration in ramstage */
+static const struct pad_config gpio_table[] = {
+	/* ToDo: Fill gpio configuration */
+};
+
+/* Early pad configuration in bootblock */
+static const struct pad_config early_gpio_table[] = {
+	/* ToDo: Fill early gpio configuration */
+};
+
+const struct pad_config *__weak variant_gpio_table(size_t *num)
+{
+	*num = ARRAY_SIZE(gpio_table);
+	return gpio_table;
+}
+
+const struct pad_config *__weak variant_early_gpio_table(size_t *num)
+{
+	*num = ARRAY_SIZE(early_gpio_table);
+	return early_gpio_table;
+}

src/mainboard/google/brya/variants/baseboard/include/baseboard/variants.h

@@ -6,4 +6,11 @@
 #include <soc/gpio.h>
 #include <stdint.h>
 
+/* The next set of functions return the gpio table and fill in the number of entries for
+ * each table.
+ */
+
+const struct pad_config *variant_gpio_table(size_t *num);
+const struct pad_config *variant_early_gpio_table(size_t *num);
+
 #endif /*__BASEBOARD_VARIANTS_H__ */

src/mainboard/google/brya/variants/brya0/include/variant/gpio.h

@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __MAINBOARD_GPIO_H__
+#define __MAINBOARD_GPIO_H__
+
+#include <baseboard/gpio.h>
+
+#endif /* __MAINBOARD_GPIO_H__ */