text: /**************************************************************************
   *
   * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   * All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sub license, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice (including the
   * next paragraph) shall be included in all copies or substantial portions
   * of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
   * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
   * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
   * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
   * USE OR OTHER DEALINGS IN THE SOFTWARE.
   *
   **************************************************************************/
  /*
   * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
   * 	    Jerome Glisse
   */
  #include <linux/module.h>
  #include <linux/device.h>
  #include <linux/sched.h>
  #include <drm/ttm/ttm_module.h>
  #include <drm/drm_sysfs.h>
  
  static DECLARE_WAIT_QUEUE_HEAD(exit_q);
  static atomic_t device_released;
  
  static struct device_type ttm_drm_class_type = {
  	.name = "ttm",
  	/**
  	 * Add pm ops here.
  	 */
  };
  
  static void ttm_drm_class_device_release(struct device *dev)
  {
  	atomic_set(&device_released, 1);
  	wake_up_all(&exit_q);
  }
  
  static struct device ttm_drm_class_device = {
  	.type = &ttm_drm_class_type,
  	.release = &ttm_drm_class_device_release
  };
  
  struct kobject *ttm_get_kobj(void)
  {
  	struct kobject *kobj = &ttm_drm_class_device.kobj;
  	BUG_ON(kobj == NULL);
  	return kobj;
  }
  
  static int __init ttm_init(void)
  {
  	int ret;
  
  	ret = dev_set_name(&ttm_drm_class_device, "ttm");
  	if (unlikely(ret != 0))
  		return ret;
  
  	atomic_set(&device_released, 0);
  	ret = drm_class_device_register(&ttm_drm_class_device);
  	if (unlikely(ret != 0))
  		goto out_no_dev_reg;
  
  	return 0;
  out_no_dev_reg:
  	atomic_set(&device_released, 1);
  	wake_up_all(&exit_q);
  	return ret;
  }
  
  static void __exit ttm_exit(void)
  {
  	drm_class_device_unregister(&ttm_drm_class_device);
  
  	/**
  	 * Refuse to unload until the TTM device is released.
  	 * Not sure this is 100% needed.
  	 */
  
  	wait_event(exit_q, atomic_read(&device_released) == 1);
  }
  
  module_init(ttm_init);
  module_exit(ttm_exit);
  
  MODULE_AUTHOR("Thomas Hellstrom, Jerome Glisse");
  MODULE_DESCRIPTION("TTM memory manager subsystem (for DRM device)");
  MODULE_LICENSE("GPL and additional rights");
  