staging/mei: AMT Watchdog

code that open connection and invoke
heartbeats to the AMT Watchdog client/feature, if exists

Connect to WD Client, if exists Send Start WD Command.
Every 2 secs send heartbeats.
On System shutdown/suspends, send Stop WD command.

This is intermediate stage before moving this code to standalone watchdog
driver.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Itzhak Tzeel-Krupp <itzhak.tzeel-krupp@intel.com>
Signed-off-by: Oren Weil <oren.jer.weil@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/mei/wd.c

+/*
+ *
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ * Copyright (c) 2003-2011, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/pci.h>
+#include <linux/sched.h>
+
+#include "mei_dev.h"
+#include "hw.h"
+#include "interface.h"
+#include "mei.h"
+
+/*
+ * MEI Watchdog Module Parameters
+ */
+static u16 watchdog_timeout = AMT_WD_VALUE;
+module_param(watchdog_timeout, ushort, 0);
+MODULE_PARM_DESC(watchdog_timeout,
+		"Intel(R) AMT Watchdog timeout value in seconds. (default="
+					__MODULE_STRING(AMT_WD_VALUE)
+					", disable=0)");
+
+static const u8 mei_start_wd_params[] = { 0x02, 0x12, 0x13, 0x10 };
+static const u8 mei_stop_wd_params[] = { 0x02, 0x02, 0x14, 0x10 };
+
+const u8 mei_wd_state_independence_msg[3][4] = {
+	{0x05, 0x02, 0x51, 0x10},
+	{0x05, 0x02, 0x52, 0x10},
+	{0x07, 0x02, 0x01, 0x10}
+};
+
+/* UUIDs for AMT F/W clients */
+const uuid_le mei_wd_guid = UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, 0x89,
+						0x9D, 0xA9, 0x15, 0x14, 0xCB,
+						0x32, 0xAB);
+
+
+void mei_wd_start_setup(struct mei_device *dev)
+{
+	dev_dbg(&dev->pdev->dev, "dev->wd_timeout=%d.\n", dev->wd_timeout);
+	memcpy(dev->wd_data, mei_start_wd_params, MEI_WD_PARAMS_SIZE);
+	memcpy(dev->wd_data + MEI_WD_PARAMS_SIZE,
+		&dev->wd_timeout, sizeof(u16));
+}
+
+/**
+ * host_init_wd - mei initialization wd.
+ *
+ * @dev: the device structure
+ */
+void mei_wd_host_init(struct mei_device *dev)
+{
+	mei_init_file_private(&dev->wd_cl, dev);
+
+	/* look for WD client and connect to it */
+	dev->wd_cl.state = MEI_FILE_DISCONNECTED;
+	dev->wd_timeout = watchdog_timeout;
+
+	if (dev->wd_timeout > 0) {
+		mei_wd_start_setup(dev);
+		/* find ME WD client */
+		mei_find_me_client_update_filext(dev, &dev->wd_cl,
+					&mei_wd_guid, MEI_WD_HOST_CLIENT_ID);
+
+		dev_dbg(&dev->pdev->dev, "check wd_cl\n");
+		if (MEI_FILE_CONNECTING == dev->wd_cl.state) {
+			if (!mei_connect(dev, &dev->wd_cl)) {
+				dev_dbg(&dev->pdev->dev, "Failed to connect to WD client\n");
+				dev->wd_cl.state = MEI_FILE_DISCONNECTED;
+				dev->wd_cl.host_client_id = 0;
+				host_init_iamthif(dev) ;
+			} else {
+				dev->wd_cl.timer_count = CONNECT_TIMEOUT;
+			}
+		} else {
+			dev_dbg(&dev->pdev->dev, "Failed to find WD client\n");
+			host_init_iamthif(dev) ;
+		}
+	} else {
+		dev->wd_bypass = true;
+		dev_dbg(&dev->pdev->dev, "WD requested to be disabled\n");
+		host_init_iamthif(dev) ;
+	}
+}
+
+/**
+ * mei_wd_send - sends watch dog message to fw.
+ *
+ * @dev: the device structure
+ *
+ * returns 0 if success,
+ *	-EIO when message send fails
+ *	-EINVAL when invalid message is to be sent
+ */
+int mei_wd_send(struct mei_device *dev)
+{
+	struct mei_msg_hdr *mei_hdr;
+
+	mei_hdr = (struct mei_msg_hdr *) &dev->wr_msg_buf[0];
+	mei_hdr->host_addr = dev->wd_cl.host_client_id;
+	mei_hdr->me_addr = dev->wd_cl.me_client_id;
+	mei_hdr->msg_complete = 1;
+	mei_hdr->reserved = 0;
+
+	if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_PARAMS_SIZE))
+		mei_hdr->length = MEI_START_WD_DATA_SIZE;
+	else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_PARAMS_SIZE))
+		mei_hdr->length = MEI_WD_PARAMS_SIZE;
+	else
+		return -EINVAL;
+
+	if (mei_write_message(dev, mei_hdr, dev->wd_data, mei_hdr->length))
+		return 0;
+	return -EIO;
+}
+
+int mei_wd_stop(struct mei_device *dev, bool preserve)
+{
+	int ret;
+	u16 wd_timeout = dev->wd_timeout;
+
+	cancel_delayed_work(&dev->wd_work);
+	if (dev->wd_cl.state != MEI_FILE_CONNECTED || !dev->wd_timeout)
+		return 0;
+
+	dev->wd_timeout = 0;
+	dev->wd_due_counter = 0;
+	memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_PARAMS_SIZE);
+	dev->stop = 1;
+
+	ret = mei_flow_ctrl_creds(dev, &dev->wd_cl);
+	if (ret < 0)
+		goto out;
+
+	if (ret && dev->mei_host_buffer_is_empty) {
+		ret = 0;
+		dev->mei_host_buffer_is_empty = 0;
+
+		if (!mei_wd_send(dev)) {
+			ret = mei_flow_ctrl_reduce(dev, &dev->wd_cl);
+			if (ret)
+				goto out;
+		} else {
+			dev_dbg(&dev->pdev->dev, "send stop WD failed\n");
+		}
+
+		dev->wd_pending = 0;
+	} else {
+		dev->wd_pending = 1;
+	}
+	dev->wd_stopped = 0;
+	mutex_unlock(&dev->device_lock);
+
+	ret = wait_event_interruptible_timeout(dev->wait_stop_wd,
+					dev->wd_stopped, 10 * HZ);
+	mutex_lock(&dev->device_lock);
+	if (!dev->wd_stopped)
+		dev_dbg(&dev->pdev->dev, "stop wd failed to complete.\n");
+	else
+		dev_dbg(&dev->pdev->dev, "stop wd complete.\n");
+
+	if (preserve)
+		dev->wd_timeout = wd_timeout;
+
+out:
+	return ret;
+}
+