soc/intel/cannonlake: Add cannonlake ACPI GPIO op

Follow instrcution from https://doc.coreboot.org/acpi/gpio.html to
implement GPIO toggling method, covered for both CNP_LP and CNP_H pch.

BUG=N/A
TEST=Build and boot up fine on sarien platform, add an dummy STSX in
DSDT table, read back from iotools to confirm the GPIO tx state get
updated.

Signed-off-by: Lijian Zhao <lijian.zhao@intel.com>
Change-Id: I006a6a8fc580c73ac0938968397a628a4ffe504f
Reviewed-on: https://review.coreboot.org/c/30461
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 38 insertions, 1 deletions

diff --git a/src/soc/intel/cannonlake/acpi.c b/src/soc/intel/cannonlake/acpi.c
index 84dfdad286..4dab3342f7 100644
--- a/src/soc/intel/cannonlake/acpi.c
+++ b/src/soc/intel/cannonlake/acpi.c
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2009 coresystems GmbH
  * Copyright (C) 2014 Google Inc.
- * Copyright (C) 2017 Intel Corporation.
+ * Copyright (C) 2017-2018 Intel Corporation.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -248,3 +248,40 @@ int soc_madt_sci_irq_polarity(int sci)
 {
 	return MP_IRQ_POLARITY_HIGH;
 }
+
+static int acpigen_soc_gpio_op(const char *op, unsigned int gpio_num)
+{
+	/* 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)
+{
+	/* 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.PCI0.GRXS", gpio_num);
+}
+
+int acpigen_soc_get_tx_gpio(unsigned int gpio_num)
+{
+	return acpigen_soc_get_gpio_state("\\_SB.PCI0.GTXS", gpio_num);
+}
+
+int acpigen_soc_set_tx_gpio(unsigned int gpio_num)
+{
+	return acpigen_soc_gpio_op("\\_SB.PCI0.STXS", gpio_num);
+}
+
+int acpigen_soc_clear_tx_gpio(unsigned int gpio_num)
+{
+	return acpigen_soc_gpio_op("\\_SB.PCI0.CTXS", gpio_num);
+}