soc/amd/cezanne: Add GRXS and GTXS method

Add GRXS and GTXS support. Move the gpio method into common place.

Signed-off-by: Eric Lai <ericr_lai@compal.corp-partner.google.com>
Change-Id: I8ba377179d6976cf26ed0dc521d8e4eff051dc85
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52202
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/src/soc/amd/common/block/acpi/gpio.c b/src/soc/amd/common/block/acpi/gpio.c
new file mode 100644
index 0000000..15ee292
--- /dev/null
+++ b/src/soc/amd/common/block/acpi/gpio.c
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <acpi/acpigen.h>
+#include <console/console.h>
+#include <soc/gpio.h>
+
+static int acpigen_soc_gpio_op(const char *op, unsigned int gpio_num)
+{
+	if (gpio_num >= SOC_GPIO_TOTAL_PINS) {
+		printk(BIOS_WARNING, "Warning: Pin %d should be smaller than"
+					" %d\n", gpio_num, SOC_GPIO_TOTAL_PINS);
+		return -1;
+	}
+	/* op (gpio_num) */
+	acpigen_emit_namestring(op);
+	acpigen_write_integer(gpio_num);
+	return 0;
+}
+
+static int acpigen_soc_get_gpio_state(const char *op, unsigned int gpio_num)
+{
+	if (gpio_num >= SOC_GPIO_TOTAL_PINS) {
+		printk(BIOS_WARNING, "Warning: Pin %d should be smaller than"
+					" %d\n", gpio_num, SOC_GPIO_TOTAL_PINS);
+		return -1;
+	}
+	/* Store (op (gpio_num), Local0) */
+	acpigen_write_store();
+	acpigen_soc_gpio_op(op, gpio_num);
+	acpigen_emit_byte(LOCAL0_OP);
+	return 0;
+}
+
+int acpigen_soc_read_rx_gpio(unsigned int gpio_num)
+{
+	return acpigen_soc_get_gpio_state("\\_SB.GRXS", gpio_num);
+}
+
+int acpigen_soc_get_tx_gpio(unsigned int gpio_num)
+{
+	return acpigen_soc_get_gpio_state("\\_SB.GTXS", gpio_num);
+}
+
+int acpigen_soc_set_tx_gpio(unsigned int gpio_num)
+{
+	return acpigen_soc_gpio_op("\\_SB.STXS", gpio_num);
+}
+
+int acpigen_soc_clear_tx_gpio(unsigned int gpio_num)
+{
+	return acpigen_soc_gpio_op("\\_SB.CTXS", gpio_num);
+}