drivers/generic/bayhub: Add driver for BayHub BH720

Add a driver which puts the device into power-saving mode.

BUG=b:73726008
BRANCH=none
TEST=boot and see this message:
BayHub BH720: Power-saving enabled 110103
From linux:
$ iotools pci_read32 2 0 0 0x90
0x00110103

Change-Id: Idbfb114f3782c9386ce9b487c3abdb0afbc4a0d9
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://review.coreboot.org/25966
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/src/drivers/generic/bayhub/chip.h b/src/drivers/generic/bayhub/chip.h
new file mode 100644
index 0000000000..7df78270b8
--- /dev/null
+++ b/src/drivers/generic/bayhub/chip.h
@@ -0,0 +1,24 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 Google LLC.
+ *
+ * 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
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <arch/acpi_device.h>
+
+/*
+ * Bayhub BG720 PCI to eMMC bridge
+ */
+struct drivers_generic_bayhub_config {
+	/* 1 to enable power-saving mode, 0 to disable */
+	int power_saving;
+};