1 files changed, 257 insertions, 0 deletions
diff --git a/src/ec/google/wilco/mailbox.c b/src/ec/google/wilco/mailbox.c
new file mode 100644
index 0000000000..1c38a5b880
--- /dev/null
+++ b/src/ec/google/wilco/mailbox.c
@@ -0,0 +1,257 @@
+/*
+ * 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/io.h>
+#include <console/console.h>
+#include <delay.h>
+#include <ec/google/common/mec.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <timer.h>
+#include <types.h>
+
+#include "ec.h"
+
+/* Mailbox ID */
+#define EC_MAILBOX_ID			0x00f0
+
+/* Version of mailbox interface */
+#define EC_MAILBOX_VERSION		0
+
+/* Command to start mailbox transaction */
+#define EC_MAILBOX_START_COMMAND	0xda
+
+/* Version of EC protocol */
+#define EC_MAILBOX_PROTO_VERSION	3
+
+/* Max number of bytes in protocol data payload */
+#define EC_MAILBOX_DATA_SIZE		32
+
+/* Number of header bytes to be counted as data bytes */
+#define EC_MAILBOX_DATA_EXTRA		2
+
+/* Maximum timeout */
+#define EC_MAILBOX_TIMEOUT_MS		MSECS_PER_SEC
+
+/* EC response flags */
+#define EC_CMDR_DATA		BIT(0)	/* Data ready for host to read */
+#define EC_CMDR_PENDING		BIT(1)	/* Write pending to EC */
+#define EC_CMDR_BUSY		BIT(2)	/* EC is busy processing a command */
+#define EC_CMDR_CMD		BIT(3)	/* Last host write was a command */
+
+/* Request to EC */
+struct wilco_ec_request {
+	uint8_t struct_version;		/* version (=3) */
+	uint8_t checksum;		/* sum of all bytes must be 0 */
+	uint16_t mailbox_id;		/* mailbox identifier */
+	uint8_t mailbox_version;	/* mailbox version (=0) */
+	uint8_t reserved1;		/* unused (=0) */
+	uint16_t data_size;		/* length (data + 2 bytes of header) */
+	uint8_t command;		/* mailbox command */
+	uint8_t reserved2;		/* unused (=0) */
+} __packed;
+
+/* Response from EC */
+struct wilco_ec_response {
+	uint8_t struct_version;		/* version (=3) */
+	uint8_t checksum;		/* sum of all bytes must be 0 */
+	uint16_t result;		/* result code */
+	uint16_t data_size;		/* length of data buffer (always 32) */
+	uint8_t reserved[3];		/* unused (=0) */
+	uint8_t data[EC_MAILBOX_DATA_SIZE];
+} __packed;
+
+struct wilco_ec_message {
+	uint8_t command;		/* mailbox command code */
+	uint8_t result;			/* request result */
+	size_t request_size;		/* bytes to send to the EC */
+	size_t response_size;		/* bytes expected from the EC */
+	enum wilco_ec_msg_type type;	/* message type */
+	/*
+	 * This data buffer will contain the request data when passed to
+	 * wilco_ec_message() and will contain the response data on return.
+	 */
+	uint8_t data[EC_MAILBOX_DATA_SIZE];
+};
+
+static bool wilco_ec_response_timed_out(void)
+{
+	uint8_t mask = EC_CMDR_PENDING | EC_CMDR_BUSY;
+	struct stopwatch sw;
+
+	stopwatch_init_msecs_expire(&sw, EC_MAILBOX_TIMEOUT_MS);
+
+	while (inb(CONFIG_EC_BASE_HOST_COMMAND) & mask) {
+		if (stopwatch_expired(&sw)) {
+			printk(BIOS_ERR, "%s: Command timeout\n", __func__);
+			return true; /* Timed out */
+		}
+		mdelay(1);
+	}
+
+	return false; /* Did not time out */
+}
+
+static uint8_t wilco_ec_checksum(void *data, size_t size)
+{
+	uint8_t *data_bytes = (uint8_t *)data;
+	uint8_t checksum = 0;
+	size_t i;
+
+	for (i = 0; i < size; i++)
+		checksum += data_bytes[i];
+
+	return checksum;
+}
+
+static void wilco_ec_prepare(struct wilco_ec_message *msg,
+			     struct wilco_ec_request *rq)
+{
+	memset(rq, 0, sizeof(*rq));
+
+	/* Fill in request packet */
+	rq->struct_version = EC_MAILBOX_PROTO_VERSION;
+	rq->mailbox_id = EC_MAILBOX_ID;
+	rq->mailbox_version = EC_MAILBOX_VERSION;
+	rq->data_size = msg->request_size + EC_MAILBOX_DATA_EXTRA;
+	rq->command = msg->command;
+
+	/* Checksum header and data */
+	rq->checksum = wilco_ec_checksum(rq, sizeof(*rq));
+	rq->checksum += wilco_ec_checksum(msg->data, msg->request_size);
+	rq->checksum = -rq->checksum;
+}
+
+static int wilco_ec_transfer(struct wilco_ec_message *msg)
+{
+	struct wilco_ec_request rq;
+	struct wilco_ec_response rs;
+	uint8_t checksum;
+	size_t skip_size;
+
+	/* Prepare request packet */
+	wilco_ec_prepare(msg, &rq);
+
+	/* Write request header */
+	mec_io_bytes(MEC_IO_WRITE, CONFIG_EC_BASE_PACKET, 0, &rq, sizeof(rq));
+
+	/* Write request data */
+	mec_io_bytes(MEC_IO_WRITE, CONFIG_EC_BASE_PACKET, sizeof(rq),
+		     msg->data, msg->request_size);
+
+	/* Start the command */
+	outb(EC_MAILBOX_START_COMMAND, CONFIG_EC_BASE_HOST_COMMAND);
+
+	/* Wait for it to complete */
+	if (wilco_ec_response_timed_out()) {
+		printk(BIOS_ERR, "%s: response timed out\n", __func__);
+		return -1;
+	}
+
+	/* Some commands will put the EC into a state where it cannot respond */
+	if (msg->type == WILCO_EC_MSG_NO_RESPONSE) {
+		printk(BIOS_DEBUG, "%s: EC does not respond to this command\n",
+		       __func__);
+		return 0;
+	}
+
+	/* Check result */
+	msg->result = inb(CONFIG_EC_BASE_HOST_DATA);
+	if (msg->result != 0) {
+		printk(BIOS_ERR, "%s: bad response: 0x%02x\n",
+		       __func__, msg->result);
+		return -1;
+	}
+
+	/* Read back response */
+	checksum = mec_io_bytes(MEC_IO_READ, CONFIG_EC_BASE_PACKET, 0,
+				&rs, sizeof(rs));
+	if (checksum) {
+		printk(BIOS_ERR, "%s: bad checksum %02x\n", __func__, checksum);
+		return -1;
+	}
+	msg->result = rs.result;
+
+	/* EC always returns EC_MAILBOX_DATA_SIZE bytes */
+	if (rs.data_size > EC_MAILBOX_DATA_SIZE) {
+		printk(BIOS_ERR, "%s: packet too long (%d bytes, expected %d)",
+		       __func__, rs.data_size, EC_MAILBOX_DATA_SIZE);
+		return -1;
+	}
+
+	/* Skip response data bytes as requested */
+	skip_size = (msg->type == WILCO_EC_MSG_DEFAULT) ? 1 : 0;
+
+	if (msg->response_size > rs.data_size - skip_size) {
+		printk(BIOS_ERR, "%s: data too short (%lu bytes, expected %zu)",
+		       __func__, rs.data_size - skip_size, msg->response_size);
+		return -1;
+	}
+
+	memcpy(msg->data, rs.data + skip_size, msg->response_size);
+
+	/* Return actual amount of data received */
+	return msg->response_size;
+}
+
+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)
+{
+	struct wilco_ec_message msg = {
+		.command = command,
+		.request_size = request_size,
+		.response_size = response_size,
+		.type = type,
+	};
+	int ret;
+
+	if (request_size > EC_MAILBOX_DATA_SIZE) {
+		printk(BIOS_ERR, "%s: provided request data too large: %zu\n",
+		       __func__, request_size);
+		return -1;
+	}
+	if (response_size > EC_MAILBOX_DATA_SIZE) {
+		printk(BIOS_ERR, "%s: expected response data too large: %zu\n",
+		       __func__, response_size);
+		return -1;
+	}
+	if (request_size && !request_data) {
+		printk(BIOS_ERR, "%s: request data missing\n", __func__);
+		return -1;
+	}
+	if (response_size && !response_data) {
+		printk(BIOS_ERR, "%s: request data missing\n", __func__);
+		return -1;
+	}
+
+	/* Copy request data if present */
+	if (request_size)
+		memcpy(msg.data, request_data, request_size);
+
+	/* Do the EC transfer */
+	ret = wilco_ec_transfer(&msg);
+
+	/* Copy response data if present */
+	if (ret > 0 && response_size)
+		memcpy(response_data, msg.data, response_size);
+
+	/* Return error if message result is non-zero */
+	if (ret >= 0 && msg.result)
+		ret = -1;
+
+	return ret;
+}