ec/google/wilco: Add Wilco EC mailbox interface

The Google "Wilco" Embedded Controller is a new embedded controller that
will be used in some future devices.  The mailbox interface is simliar
to the existing Chromium EC protocol version 3, but not close enough
that it was convenient to re-use the full Chrome EC driver.

This commit adds the basic mailbox interface for ramstage which will be
used by future commits to send varous mailbox commands during the boot
process.  The IO base addresses for the mailbox interface are defined in
Kconfig so they can be changed by the mainboard if needed.

Change-Id: I8520dadfa982c9d14357cf2aa644e255cef425c2
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/29113
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/src/ec/google/wilco/ec.h b/src/ec/google/wilco/ec.h
new file mode 100644
index 0000000000..0ce6166322
--- /dev/null
+++ b/src/ec/google/wilco/ec.h
@@ -0,0 +1,47 @@
+/*
+ * 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.
+ */
+
+#ifndef EC_GOOGLE_WILCO_EC_H
+#define EC_GOOGLE_WILCO_EC_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* Different supported message types */
+enum wilco_ec_msg_type {
+	WILCO_EC_MSG_RAW,		/* Raw message, do not skip any data */
+	WILCO_EC_MSG_DEFAULT,		/* Skip 1 byte of response data */
+	WILCO_EC_MSG_NO_RESPONSE,	/* EC does not respond to command */
+};
+
+/**
+ * wilco_ec_mailbox
+ *
+ * Send a command request to the EC mailbox and receive the response.
+ *
+ * @type:          Mailbox message type, see enum above
+ * @command:       Command to execute
+ * @request_data:  Request data buffer
+ * @request_size:  Number of bytes in request data buffer (max 32)
+ * @response_data: Response data buffer
+ * @response_size: Number of bytes in response data buffer (max 32)
+ *
+ * @return number of bytes received, negative error code on failure
+ */
+int wilco_ec_mailbox(enum wilco_ec_msg_type type, uint8_t command,
+		     const void *request_data, size_t request_size,
+		     void *response_data, size_t response_size);
+
+#endif /* EC_GOOGLE_WILCO_EC_H */