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      1 /*	$NetBSD: ttm_module.c,v 1.3 2021/12/18 23:45:44 riastradh Exp $	*/
      2 
      3 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
      4 /**************************************************************************
      5  *
      6  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
      7  * All Rights Reserved.
      8  *
      9  * Permission is hereby granted, free of charge, to any person obtaining a
     10  * copy of this software and associated documentation files (the
     11  * "Software"), to deal in the Software without restriction, including
     12  * without limitation the rights to use, copy, modify, merge, publish,
     13  * distribute, sub license, and/or sell copies of the Software, and to
     14  * permit persons to whom the Software is furnished to do so, subject to
     15  * the following conditions:
     16  *
     17  * The above copyright notice and this permission notice (including the
     18  * next paragraph) shall be included in all copies or substantial portions
     19  * of the Software.
     20  *
     21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     23  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
     24  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
     25  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
     26  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
     27  * USE OR OTHER DEALINGS IN THE SOFTWARE.
     28  *
     29  **************************************************************************/
     30 /*
     31  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
     32  * 	    Jerome Glisse
     33  */
     34 #include <sys/cdefs.h>
     35 __KERNEL_RCSID(0, "$NetBSD: ttm_module.c,v 1.3 2021/12/18 23:45:44 riastradh Exp $");
     36 
     37 #include <linux/module.h>
     38 #include <linux/device.h>
     39 #include <linux/sched.h>
     40 #include <drm/ttm/ttm_module.h>
     41 #include <drm/drm_sysfs.h>
     42 
     43 static DECLARE_WAIT_QUEUE_HEAD(exit_q);
     44 static atomic_t device_released;
     45 
     46 static struct device_type ttm_drm_class_type = {
     47 	.name = "ttm",
     48 	/**
     49 	 * Add pm ops here.
     50 	 */
     51 };
     52 
     53 static void ttm_drm_class_device_release(struct device *dev)
     54 {
     55 	atomic_set(&device_released, 1);
     56 	wake_up_all(&exit_q);
     57 }
     58 
     59 static struct device ttm_drm_class_device = {
     60 	.type = &ttm_drm_class_type,
     61 	.release = &ttm_drm_class_device_release
     62 };
     63 
     64 struct kobject *ttm_get_kobj(void)
     65 {
     66 	struct kobject *kobj = &ttm_drm_class_device.kobj;
     67 	BUG_ON(kobj == NULL);
     68 	return kobj;
     69 }
     70 
     71 static int __init ttm_init(void)
     72 {
     73 	int ret;
     74 
     75 	ret = dev_set_name(&ttm_drm_class_device, "ttm");
     76 	if (unlikely(ret != 0))
     77 		return ret;
     78 
     79 	atomic_set(&device_released, 0);
     80 	ret = drm_class_device_register(&ttm_drm_class_device);
     81 	if (unlikely(ret != 0))
     82 		goto out_no_dev_reg;
     83 
     84 	return 0;
     85 out_no_dev_reg:
     86 	atomic_set(&device_released, 1);
     87 	wake_up_all(&exit_q);
     88 	return ret;
     89 }
     90 
     91 static void __exit ttm_exit(void)
     92 {
     93 	drm_class_device_unregister(&ttm_drm_class_device);
     94 
     95 	/**
     96 	 * Refuse to unload until the TTM device is released.
     97 	 * Not sure this is 100% needed.
     98 	 */
     99 
    100 	wait_event(exit_q, atomic_read(&device_released) == 1);
    101 }
    102 
    103 module_init(ttm_init);
    104 module_exit(ttm_exit);
    105 
    106 MODULE_AUTHOR("Thomas Hellstrom, Jerome Glisse");
    107 MODULE_DESCRIPTION("TTM memory manager subsystem (for DRM device)");
    108 MODULE_LICENSE("GPL and additional rights");
    109