/*
   *
   * 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/export.h>
  #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 "hbm.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(RESETTING);
  	MEI_DEV_STATE(DISABLED);
  	MEI_DEV_STATE(POWER_DOWN);
  	MEI_DEV_STATE(POWER_UP);
  	default:
  		return "unknown";
  	}
  #undef MEI_DEV_STATE
  }
  
  
  /**
   * mei_cancel_work. Cancel mei background jobs
   *
   * @dev: the device structure
   *
   * returns 0 on success or < 0 if the reset hasn't succeeded
   */
  void mei_cancel_work(struct mei_device *dev)
  {
  	cancel_work_sync(&dev->init_work);
  	cancel_work_sync(&dev->reset_work);
  
  	cancel_delayed_work(&dev->timer_work);
  }
  EXPORT_SYMBOL_GPL(mei_cancel_work);
  
  /**
   * mei_reset - resets host and fw.
   *
   * @dev: the device structure
   */
  int mei_reset(struct mei_device *dev)
  {
  	enum mei_dev_state state = dev->dev_state;
  	bool interrupts_enabled;
  	int ret;
  
  	if (state != MEI_DEV_INITIALIZING &&
  	    state != MEI_DEV_DISABLED &&
  	    state != MEI_DEV_POWER_DOWN &&
  	    state != MEI_DEV_POWER_UP)
  		dev_warn(&dev->pdev->dev, "unexpected reset: dev_state = %s
  ",
  			 mei_dev_state_str(state));
  
  	/* we're already in reset, cancel the init timer
  	 * if the reset was called due the hbm protocol error
  	 * we need to call it before hw start
  	 * so the hbm watchdog won't kick in
  	 */
  	mei_hbm_idle(dev);
  
  	/* enter reset flow */
  	interrupts_enabled = state != MEI_DEV_POWER_DOWN;
  	dev->dev_state = MEI_DEV_RESETTING;
  
  	dev->reset_count++;
  	if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
  		dev_err(&dev->pdev->dev, "reset: reached maximal consecutive resets: disabling the device
  ");
  		dev->dev_state = MEI_DEV_DISABLED;
  		return -ENODEV;
  	}
  
  	ret = mei_hw_reset(dev, interrupts_enabled);
  	/* fall through and remove the sw state even if hw reset has failed */
  
  	/* no need to clean up software state in case of power up */
  	if (state != MEI_DEV_INITIALIZING &&
  	    state != MEI_DEV_POWER_UP) {
  
  		/* remove all waiting requests */
  		mei_cl_all_write_clear(dev);
  
  		mei_cl_all_disconnect(dev);
  
  		/* wake up all readers and writers so they can be interrupted */
  		mei_cl_all_wakeup(dev);
  
  		/* remove entry if already in list */
  		dev_dbg(&dev->pdev->dev, "remove iamthif and wd from the file list.
  ");
  		mei_cl_unlink(&dev->wd_cl);
  		mei_cl_unlink(&dev->iamthif_cl);
  		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 (ret) {
  		dev_err(&dev->pdev->dev, "hw_reset failed ret = %d
  ", ret);
  		dev->dev_state = MEI_DEV_DISABLED;
  		return ret;
  	}
  
  	if (state == MEI_DEV_POWER_DOWN) {
  		dev_dbg(&dev->pdev->dev, "powering down: end of reset
  ");
  		dev->dev_state = MEI_DEV_DISABLED;
  		return 0;
  	}
  
  	ret = mei_hw_start(dev);
  	if (ret) {
  		dev_err(&dev->pdev->dev, "hw_start failed ret = %d
  ", ret);
  		dev->dev_state = MEI_DEV_DISABLED;
  		return ret;
  	}
  
  	dev_dbg(&dev->pdev->dev, "link is established start sending messages.
  ");
  
  	dev->dev_state = MEI_DEV_INIT_CLIENTS;
  	ret = mei_hbm_start_req(dev);
  	if (ret) {
  		dev_err(&dev->pdev->dev, "hbm_start failed ret = %d
  ", ret);
  		dev->dev_state = MEI_DEV_DISABLED;
  		return ret;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(mei_reset);
  
  /**
   * mei_start - initializes host and fw to start work.
   *
   * @dev: the device structure
   *
   * returns 0 on success, <0 on failure.
   */
  int mei_start(struct mei_device *dev)
  {
  	mutex_lock(&dev->device_lock);
  
  	/* acknowledge interrupt and stop interrupts */
  	mei_clear_interrupts(dev);
  
  	mei_hw_config(dev);
  
  	dev_dbg(&dev->pdev->dev, "reset in start the mei device.
  ");
  
  	dev->dev_state = MEI_DEV_INITIALIZING;
  	dev->reset_count = 0;
  	mei_reset(dev);
  
  	if (dev->dev_state == MEI_DEV_DISABLED) {
  		dev_err(&dev->pdev->dev, "reset failed");
  		goto err;
  	}
  
  	if (mei_hbm_start_wait(dev)) {
  		dev_err(&dev->pdev->dev, "HBM haven't started");
  		goto err;
  	}
  
  	if (!mei_host_is_ready(dev)) {
  		dev_err(&dev->pdev->dev, "host is not ready.
  ");
  		goto err;
  	}
  
  	if (!mei_hw_is_ready(dev)) {
  		dev_err(&dev->pdev->dev, "ME is not ready.
  ");
  		goto err;
  	}
  
  	if (!mei_hbm_version_is_supported(dev)) {
  		dev_dbg(&dev->pdev->dev, "MEI start failed.
  ");
  		goto err;
  	}
  
  	dev_dbg(&dev->pdev->dev, "link layer has been established.
  ");
  
  	mutex_unlock(&dev->device_lock);
  	return 0;
  err:
  	dev_err(&dev->pdev->dev, "link layer initialization failed.
  ");
  	dev->dev_state = MEI_DEV_DISABLED;
  	mutex_unlock(&dev->device_lock);
  	return -ENODEV;
  }
  EXPORT_SYMBOL_GPL(mei_start);
  
  /**
   * mei_restart - restart device after suspend
   *
   * @dev: the device structure
   *
   * returns 0 on success or -ENODEV if the restart hasn't succeeded
   */
  int mei_restart(struct mei_device *dev)
  {
  	int err;
  
  	mutex_lock(&dev->device_lock);
  
  	mei_clear_interrupts(dev);
  
  	dev->dev_state = MEI_DEV_POWER_UP;
  	dev->reset_count = 0;
  
  	err = mei_reset(dev);
  
  	mutex_unlock(&dev->device_lock);
  
  	if (err || dev->dev_state == MEI_DEV_DISABLED)
  		return -ENODEV;
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(mei_restart);
  
  
  static void mei_reset_work(struct work_struct *work)
  {
  	struct mei_device *dev =
  		container_of(work, struct mei_device,  reset_work);
  
  	mutex_lock(&dev->device_lock);
  
  	mei_reset(dev);
  
  	mutex_unlock(&dev->device_lock);
  
  	if (dev->dev_state == MEI_DEV_DISABLED)
  		dev_err(&dev->pdev->dev, "reset failed");
  }
  
  void mei_stop(struct mei_device *dev)
  {
  	dev_dbg(&dev->pdev->dev, "stopping the device.
  ");
  
  	mei_cancel_work(dev);
  
  	mei_nfc_host_exit(dev);
  
  	mutex_lock(&dev->device_lock);
  
  	mei_wd_stop(dev);
  
  	dev->dev_state = MEI_DEV_POWER_DOWN;
  	mei_reset(dev);
  
  	mutex_unlock(&dev->device_lock);
  
  	mei_watchdog_unregister(dev);
  }
  EXPORT_SYMBOL_GPL(mei_stop);
  
  
  
  void mei_device_init(struct mei_device *dev)
  {
  	/* setup our list array */
  	INIT_LIST_HEAD(&dev->file_list);
  	INIT_LIST_HEAD(&dev->device_list);
  	mutex_init(&dev->device_lock);
  	init_waitqueue_head(&dev->wait_hw_ready);
  	init_waitqueue_head(&dev->wait_recvd_msg);
  	init_waitqueue_head(&dev->wait_stop_wd);
  	dev->dev_state = MEI_DEV_INITIALIZING;
  	dev->reset_count = 0;
  
  	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);
  
  	INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
  	INIT_WORK(&dev->init_work, mei_host_client_init);
  	INIT_WORK(&dev->reset_work, mei_reset_work);
  
  	INIT_LIST_HEAD(&dev->wd_cl.link);
  	INIT_LIST_HEAD(&dev->iamthif_cl.link);
  	mei_io_list_init(&dev->amthif_cmd_list);
  	mei_io_list_init(&dev->amthif_rd_complete_list);
  
  	bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
  	dev->open_handle_count = 0;
  
  	/*
  	 * Reserving the first client ID
  	 * 0: Reserved for MEI Bus Message communications
  	 */
  	bitmap_set(dev->host_clients_map, 0, 1);
  }
  EXPORT_SYMBOL_GPL(mei_device_init);