google/oak: Support cr50 over I2C on rowan

This patch enables TPM2 using cr50 over I2C for the Rowan board, and
adds an mt8173 specific TPM IRQ polling function. The function relies on
the appropriate EINT input configured to trigger the ready status on
the rising edge.

The cr50 TPM is on I2C address 0x50.

The cr50 interrupt GPIO is also made available for use by depthcharge
via the coreboot tables.

BRANCH=none
BUG=b:36786804
TEST=Boot rowan w/ serial enabled, verify coreboot and depthcharge are
 configured to use IRQ flow control when talking to the Cr50 TPM.

Change-Id: If6cdd0e39e4ac86538f27f322c55c329179ee084
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-on: https://review.coreboot.org/19364
Tested-by: build bot (Jenkins)
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/src/mainboard/google/oak/tpm_tis.c b/src/mainboard/google/oak/tpm_tis.c
new file mode 100644
index 0000000000..018f02db10
--- /dev/null
+++ b/src/mainboard/google/oak/tpm_tis.c
@@ -0,0 +1,24 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2017 Google Inc.
+ *
+ * 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 <gpio.h>
+#include <tpm.h>
+
+#include "gpio.h"
+
+int tis_plat_irq_status(void)
+{
+	return gpio_eint_poll(CR50_IRQ);
+}