/*
 *
 * Intel Management Engine Interface (Intel MEI) Linux driver
 * Copyright (c) 2003-2012, 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/pci.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>

#include <linux/mei.h>

#include "mei_dev.h"
#include "client.h"

const char *mei_dev_state_str(int state)
{
#define MEI_DEV_STATE(state) case MEI_DEV_##state: return #state
	switch (state) {
	MEI_DEV_STATE(INITIALIZING);
	MEI_DEV_STATE(INIT_CLIENTS);
	MEI_DEV_STATE(ENABLED);
	MEI_DEV_STATE(RESETING);
	MEI_DEV_STATE(DISABLED);
	MEI_DEV_STATE(RECOVERING_FROM_RESET);
	MEI_DEV_STATE(POWER_DOWN);
	MEI_DEV_STATE(POWER_UP);
	default:
		return "unkown";
	}
#undef MEI_DEV_STATE
}

void mei_device_init(struct mei_device *dev)
{
	/* setup our list array */
	INIT_LIST_HEAD(&dev->file_list);
	mutex_init(&dev->device_lock);
	init_waitqueue_head(&dev->wait_recvd_msg);
	init_waitqueue_head(&dev->wait_stop_wd);
	dev->dev_state = MEI_DEV_INITIALIZING;

	mei_io_list_init(&dev->read_list);
	mei_io_list_init(&dev->write_list);
	mei_io_list_init(&dev->write_waiting_list);
	mei_io_list_init(&dev->ctrl_wr_list);
	mei_io_list_init(&dev->ctrl_rd_list);
}

/**
 * mei_hw_init - initializes host and fw to start work.
 *
 * @dev: the device structure
 *
 * returns 0 on success, <0 on failure.
 */
int mei_hw_init(struct mei_device *dev)
{
	int ret = 0;

	mutex_lock(&dev->device_lock);

	/* acknowledge interrupt and stop interupts */
	mei_clear_interrupts(dev);

	mei_hw_config(dev);

	dev->recvd_msg = false;
	dev_dbg(&dev->pdev->dev, "reset in start the mei device.\n");

	mei_reset(dev, 1);

	/* wait for ME to turn on ME_RDY */
	if (!dev->recvd_msg) {
		mutex_unlock(&dev->device_lock);
		ret = wait_event_interruptible_timeout(dev->wait_recvd_msg,
			dev->recvd_msg,
			mei_secs_to_jiffies(MEI_INTEROP_TIMEOUT));
		mutex_lock(&dev->device_lock);
	}

	if (ret <= 0 && !dev->recvd_msg) {
		dev->dev_state = MEI_DEV_DISABLED;
		dev_dbg(&dev->pdev->dev,
			"wait_event_interruptible_timeout failed"
			"on wait for ME to turn on ME_RDY.\n");
		goto err;
	}


	if (!mei_host_is_ready(dev)) {
		dev_err(&dev->pdev->dev, "host is not ready.\n");
		goto err;
	}

	if (!mei_hw_is_ready(dev)) {
		dev_err(&dev->pdev->dev, "ME is not ready.\n");
		goto err;
	}

	if (dev->version.major_version != HBM_MAJOR_VERSION ||
	    dev->version.minor_version != HBM_MINOR_VERSION) {
		dev_dbg(&dev->pdev->dev, "MEI start failed.\n");
		goto err;
	}

	dev->recvd_msg = false;
	dev_dbg(&dev->pdev->dev, "link layer has been established.\n");

	mutex_unlock(&dev->device_lock);
	return 0;
err:
	dev_err(&dev->pdev->dev, "link layer initialization failed.\n");
	dev->dev_state = MEI_DEV_DISABLED;
	mutex_unlock(&dev->device_lock);
	return -ENODEV;
}

/**
 * mei_reset - resets host and fw.
 *
 * @dev: the device structure
 * @interrupts_enabled: if interrupt should be enabled after reset.
 */
void mei_reset(struct mei_device *dev, int interrupts_enabled)
{
	bool unexpected;

	if (dev->dev_state == MEI_DEV_RECOVERING_FROM_RESET)
		return;

	unexpected = (dev->dev_state != MEI_DEV_INITIALIZING &&
			dev->dev_state != MEI_DEV_DISABLED &&
			dev->dev_state != MEI_DEV_POWER_DOWN &&
			dev->dev_state != MEI_DEV_POWER_UP);

	mei_hw_reset(dev, interrupts_enabled);


	if (dev->dev_state != MEI_DEV_INITIALIZING) {
		if (dev->dev_state != MEI_DEV_DISABLED &&
		    dev->dev_state != MEI_DEV_POWER_DOWN)
			dev->dev_state = MEI_DEV_RESETING;

		mei_cl_all_disconnect(dev);

		/* remove entry if already in list */
		dev_dbg(&dev->pdev->dev, "remove iamthif and wd from the file list.\n");
		mei_cl_unlink(&dev->wd_cl);
		if (dev->open_handle_count > 0)
			dev->open_handle_count--;
		mei_cl_unlink(&dev->iamthif_cl);
		if (dev->open_handle_count > 0)
			dev->open_handle_count--;

		mei_amthif_reset_params(dev);
		memset(&dev->wr_ext_msg, 0, sizeof(dev->wr_ext_msg));
	}

	dev->me_clients_num = 0;
	dev->rd_msg_hdr = 0;
	dev->wd_pending = false;

	if (unexpected)
		dev_warn(&dev->pdev->dev, "unexpected reset: dev_state = %s\n",
			 mei_dev_state_str(dev->dev_state));

	/* wake up all readings so they can be interrupted */
	mei_cl_all_read_wakeup(dev);

	/* remove all waiting requests */
	mei_cl_all_write_clear(dev);
}

void mei_stop(struct mei_device *dev)
{
	dev_dbg(&dev->pdev->dev, "stopping the device.\n");

	mutex_lock(&dev->device_lock);

	cancel_delayed_work(&dev->timer_work);

	mei_wd_stop(dev);

	dev->dev_state = MEI_DEV_POWER_DOWN;
	mei_reset(dev, 0);

	mutex_unlock(&dev->device_lock);

	flush_scheduled_work();
}