diff --git a/src/mainboard/google/guybrush/mainboard.c b/src/mainboard/google/guybrush/mainboard.c
index 90ecdda..72ad7a8 100644
--- a/src/mainboard/google/guybrush/mainboard.c
+++ b/src/mainboard/google/guybrush/mainboard.c
@@ -1,10 +1,89 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
+#include <amdblocks/amd_pci_util.h>
 #include <baseboard/variants.h>
 #include <device/device.h>
+#include <soc/acpi.h>
 #include <variant/ec.h>
 #include <vendorcode/google/chromeos/chromeos.h>
 
+/*
+ * These arrays set up the FCH PCI_INTR registers 0xC00/0xC01.
+ * This table is responsible for physically routing the PIC and
+ * IOAPIC IRQs to the different PCI devices on the system.  It
+ * is read and written via registers 0xC00/0xC01 as an
+ * Index/Data pair.  These values are chipset and mainboard
+ * dependent and should be updated accordingly.
+ */
+static uint8_t fch_pic_routing[0x80];
+static uint8_t fch_apic_routing[0x80];
+
+_Static_assert(sizeof(fch_pic_routing) == sizeof(fch_apic_routing),
+	"PIC and APIC FCH interrupt tables must be the same size");
+
+/*
+ * This controls the device -> IRQ routing.
+ *
+ * Hardcoded IRQs:
+ *  0: timer < soc/amd/common/acpi/lpc.asl
+ *  1: i8042 - Keyboard
+ *  2: cascade
+ *  8: rtc0 <- soc/amd/common/acpi/lpc.asl
+ *  9: acpi <- soc/amd/common/acpi/lpc.asl
+ */
+static const struct fch_irq_routing {
+	uint8_t intr_index;
+	uint8_t pic_irq_num;
+	uint8_t apic_irq_num;
+} guybrush_fch[] = {
+	{ PIRQ_A,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_B,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_C,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_D,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_E,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_F,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_G,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_H,	PIRQ_NC,	PIRQ_NC },
+
+	{ PIRQ_SCI,	ACPI_SCI_IRQ,	ACPI_SCI_IRQ },
+	{ PIRQ_SD,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_SDIO,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_SATA,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_EMMC,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_GPIO,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_I2C2,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_I2C3,	PIRQ_NC,	PIRQ_NC },
+	{ PIRQ_UART0,	 4,		 4 },
+	{ PIRQ_UART1,	 3,		 3 },
+
+	/* The MISC registers are not interrupt numbers */
+	{ PIRQ_MISC,	0xfa,		0x00 },
+	{ PIRQ_MISC0,	0x91,		0x00 },
+	{ PIRQ_HPET_L,	0x00,		0x00 },
+	{ PIRQ_HPET_H,	0x00,		0x00 },
+};
+
+static void init_tables(void)
+{
+	const struct fch_irq_routing *entry;
+	int i;
+
+	memset(fch_pic_routing, PIRQ_NC, sizeof(fch_pic_routing));
+	memset(fch_apic_routing, PIRQ_NC, sizeof(fch_apic_routing));
+
+	for (i = 0; i < ARRAY_SIZE(guybrush_fch); i++) {
+		entry = guybrush_fch + i;
+		fch_pic_routing[entry->intr_index] = entry->pic_irq_num;
+		fch_apic_routing[entry->intr_index] = entry->apic_irq_num;
+	}
+}
+
+static void pirq_setup(void)
+{
+	intr_data_ptr = fch_apic_routing;
+	picr_data_ptr = fch_pic_routing;
+}
+
 static void mainboard_configure_gpios(void)
 {
 	size_t base_num_gpios, override_num_gpios;
@@ -28,6 +107,10 @@
 	printk(BIOS_INFO, "Mainboard " CONFIG_MAINBOARD_PART_NUMBER " Enable.\n");
 
 	dev->ops->acpi_inject_dsdt = chromeos_dsdt_generator;
+
+	init_tables();
+	/* Initialize the PIRQ data structures for consumption */
+	pirq_setup();
 }
 
 struct chip_operations mainboard_ops = {